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Inventors
Hewitt, Charles W.
Application #
635779
Filed
Aug-11-2000
Published
Dec-31-2002
Current US Class
173/201
227/130
227/131
227/136
International Classes
B25C 001/04
Field of Search
227/119 227/136 227/131 227/130 227/123 227/137 227/120 173/201
Assignee
Stanley Fastenening Systems, L.P. (East Greenwich, RI)
Examiners
Smith; Scott A.
Attorney, Agent or Firm
Pillsbury Winthrop LLP
US Patent References
| 3936407 |
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Coated metal fasten... |
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| 4253598 |
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Fluid powered imp... |
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| 4433782 |
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Magazine assembl... |
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| 4671443 |
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Replaceable maga... |
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| 4741467 |
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Explosive powder c... |
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| 5452835 |
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Positioning mecha... |
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| 5579975 |
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Fastener driving to... |
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| 5810239 |
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Attachment for nail... |
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Referenced by:
View Backward References
Citation
Cite This Patent
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Abstract
A fastening device for driving a fastener into a workpiece by effecting multiple blows upon the fastener comprises a housing and a striker assembly movably mounted within the housing. The striker assembly includes a driver assembly adapted to strike the fastener to be driven into the workpiece. A nose assembly is movably mounted on the housing and has a fastener drive track along which the driver assembly and the fastener travel when the fastener is driven into the workpiece. The fastening device has a feed mechanism operatively connected to the nose assembly for mechanically advancing the fastener into the fastener drive track. The fastener drive track has a guide surface adjacent the aperture of the nose assembly to direct the fastener as it is driven into the workpiece. A releasable fastener assembly releasably secures the nose assembly to the housing of the fastening device. A control assembly controls the operation of the fastening device to conserve energy. A coil of collated roofing nails is adapted for use with the fastening device. Each of the nails of the coil of collated roofing nails is coated with a thermoplastic material that serves as a lubricant which facilitates driving of the nails.
Claims
What is claimed is:
1. A fastening device for driving a fastener within a coil of collated fasteners into a workpiece, comprising:
a housing;
a striker assembly movably mounted within said housing, said striker assembly including a driver assembly for providing a plurality of drive strokes for driving the fastener to be driven into the workpiece;
a nose assembly operatively connected to said housing, said nose assembly having a fastener drive channel along which said driver assembly and the fastener travel when the fastener is driven into the workpiece; and
a magazine assembly constructed and arranged to engage at least one fastener within said coil of fasteners in order to move a lead fastener within said coil of fasteners in a first direction toward said fastener drive channel, said lead fastener having a forward pointed tip thereof tending to be moved in a second direction opposite said first direction in response to a rearward head end thereof being impacted by said driver assembly due to the interconnection of the collation material between said lead fastener and a subsequent fastener;
said nose assembly including an angled guide surface constructed and arranged to engage the tip and head of said lead fastener as said fastener is driven, said guide surface being angled so as to direct said tip and said head of said lead fastener toward said first direction as said lead fastener is driven.
2. The fastening device according to claim 1, wherein said nose assembly further comprises a pivoted guide structure defining a pivoted guide surface disposed in opposing relation to said angled surface, said pivoted guide structure being biased towards a first position wherein said pivoted structure is disposed adjacent to said angled guide surface so that said pivoted guide surface and said angled guide surface form a fastener outlet which is dimensioned to be smaller than a head of said fastener, and wherein the head of a fastener engages said pivoted guide surface as the fastener is being driven so as to force the pivoted guide structure away from said angled guide surface against said spring bias to enable said outlet to be sufficiently sized to permit said fastener head to pass therethrough, said angled guide surface and said pivoted guide surface guidably engaging said head as said head passes thereby.
3. The fastening device according to 2, wherein said pivoted guide surface engages said fastener tip in the event said tip is deflected sufficiently by said angled guide surface.
4. The fastening device according to claim 1, wherein said angled surface forms a bottom surface of said fastener drive channel.
5. The fastening device according to claim 4, wherein said angled surface is located on a pivoting assembly, wherein said angled surface pivots away from said fastener drive channel at predetermined operating conditions of said fastening device.
6. The fastening device according to claim 5, wherein said angled surface pivots away from said fastener drive channel while the fastener is loaded into said fastener drive channel.
7. The fastening device according to claim 6, wherein said angled surface pivots away from said fastener drive channel while said magazine assembly loads the fastener into said fastener drive channel.
8. The fastening device according to claim 7, wherein said angled surface pivots away from said fastener drive channel in response to movement of at least one fastener within said magazine assembly.
9. The fastening device according to claim 1, wherein said fastener drive channel terminates at an aperture having a generally elliptical shape.
10. The fastening device according to claim 9, wherein said fastener drive channel has generally tapered interior surfaces adjacent said aperture.
11. The fastening device according to claim 1, wherein said fastener drive channel includes an axis, wherein the angled guide surface is positioned on a side of the axis that includes the magazine assembly.
12. The fastening device according to claim 1, wherein the angled guide surface is positioned within the fastener drive channel.
13. The fastening device according to claim 1, wherein the angled guide surface is adapted to engage the head of the lead fastener as the fastener is driven so as to direct the head of the lead fastener along with the tip of the lead fastener toward said first direction as said lead fastener is driven.
14. The fastener device according to claim 1, wherein the lead fastener includes a shank having a shank axis, the shank axis is positioned within the fastener drive channel prior to impact by the driver assembly such that a driver assembly axis of the driver assembly is positioned on one side of the shank axis and the angled guide surface is positioned on an opposite side of the shank axis.
15. The fastener device according to claim 14, wherein the shank axis moves as the fastener is driven by the driver assembly such that the shank axis moves from one side of the driver assembly axis to an opposite of the driver assembly axis.
16. A fastening device for driving a fastener within a group of collated fasteners into a workpiece, comprising:
a housing;
a striker assembly movably mounted within said housing, said striker assembly including a driver assembly for striking the fastener to be driven into the workpiece;
a nose assembly operatively connected to said housing, said nose assembly having a fastener drive channel along which said driver assembly and the fastener travel when the fastener is driven into the workpiece; and
a magazine assembly constructed and arranged to engage at least one fastener within said group of fasteners in order to move a lead fastener within said coil of fasteners in a first direction toward said fastener drive channel, said lead fastener having a forward pointed end thereof tending to be moved in a second direction opposite said first direction in response to a rearward head end thereof being impacted by said driver assembly due to the interconnection of the collation material between said lead fastener and a subsequent fastener;
said nose assembly including an angled guide surface that engages the tip of said lead fastener as it is being driven, said guide surface being angled so as to direct said tip of said lead fastener toward said first direction as said lead fastener is being driven,
wherein the angled guide surface engages a head of the lead fastener as it is being driven so as to direct the head of the lead fastener along with the tip of the lead fastener toward said first direction as said lead fastener is being driven.
17. A fastening device for driving a fastener within a group of collated fasteners into a workpiece, comprising:
a housing;
a striker assembly movably mounted within said housing, said striker assembly including a driver assembly for striking the fastener to be driven into the workpiece;
a nose assembly operatively connected to said housing, said nose assembly having a fastener drive channel along which said driver assembly and the fastener travel when the fastener is driven into the workpiece; and
a magazine assembly constructed and arranged to engage at least one fastener within said group of fasteners in order to move a lead fastener within said group of fasteners in a first direction toward said fastener drive channel, said lead fastener having a forward pointed end thereof tending to be moved in a second direction opposite said first direction in response to a rearward head end thereof being impacted by said driver assembly due to the interconnection of the collation material between said lead fastener and a subsequent fastener;
said nose assembly including an angled guide surface for engaging the tip of said lead fastener as it is being driven, said guide surface being angled so as to direct said tip and said head of said lead fastener toward said first direction as said lead fastener is being driven, wherein the lead fastener includes a shank having a shank axis, the shank axis is positioned within the fastener drive channel prior to impact by the driver assembly such that a driver assembly axis of the driver assembly is positioned on one side of the shank axis and the angled guide surface is positioned on an opposite side of the shank axis.
18. The fastener device according to claim 17, wherein the shank axis moves as the fastener is driven by the driver assembly such that the shank axis moves from one side of the driver assembly axis to an opposite of the driver assembly axis.
19. A multi-stroke fastening device for driving a fastener within a coil of collated fasteners into a workpiece, comprising:
a housing;
a striker assembly movably mounted within said housing, said striker assembly including a driver assembly for providing a plurality of drive strokes for driving the fastener into the workpiece;
a nose assembly operatively connected to said housing, said nose assembly having a fastener drive channel along which said driver assembly and the fastener travel when the fastener is driven into the workpiece; and
a magazine assembly constructed and arranged to engage at least one fastener within said coil of fasteners in order to move a lead fastener within said coil of fasteners in a first direction toward said fastener drive channel, said lead fastener having a forward pointed end thereof tending to be moved in a second direction opposite said first direction in response to a rearward head end thereof being impacted by said driver assembly due to the interconnection of the collation material between said lead fastener and a subsequent fastener;
said nose assembly including an angled guide surface for engaging the tip of said lead fastener as it is being driven, said guide surface being angled so as to direct said tip and said head of said lead fastener toward said first direction as said lead fastener is being driven, wherein the lead fastener includes a shank having a shank axis, the shank axis moving from one side of an axis of the driver assembly to an other side of the axis of the driver assembly as the lead fastener is being driven into the workpiece.
Description
FIELD OF THE INVENTION
The present invention relates to automatic fastening devices and, in particular, a fastening device that drives a fastener into a workpiece by effecting multiple blows upon the fastener. More specifically, the invention relates to a fastening device having a feed assembly operatively connected to a nose assembly for mechanically advancing the fastener into a fastener drive channel. Furthermore, the invention relates to a fastening device wherein a fastener drive channel has a guide surface adjacent the aperture of the nose assembly to direct the fastener as it is driven into the workpiece. The invention also relates to a fastening device having a releasable fastener assembly for releasably securing the nose assembly to the housing of the fastening device. The invention also relates to a fastening device having a control assembly for controlling the operation of the fastening device to conserve energy. Finally, the present invention relates to a coil of collated roofing nails wherein each of the nails is coated with a thermoplastic material that serves as a lubricant which facilitates driving of the nails. The coil of collated roofing nails is adapted for use with the fastening device.
BACKGROUND OF THE INVENTION
The most typical type of nailing or fastening device used to drive a fastener into a workpiece is that of the "single stroke" type. In these types of devices, a driver assembly is driven to fasten a fastener into a workpiece with a single blow or impact. A disadvantage of these devices is that they require very high levels of impact energy, especially when longer fastener lengths are used.
There have been some attempts to provide a "multi-stroke" fastening device, which employs a striker assembly, which is driven to provide a plurality of blows or impacts upon the fastener head for progressively fastening the fastener into a workpiece. Such devices have been proposed by U.S. Pat. Nos. 1,767,485; 2,796,608; 3,203,610; 4,183,453; 4,724,992; and 4,807,793. The disadvantage with these proposed devices is that the fastener striker assembly is driven through a plurality of driving strokes, the lengths of the strokes are progressively increased as the fastener is progressively driven into the workpiece. As a result, the timing for driving the striker assembly becomes more difficult to manage. In addition, because the stroke length of the striker assembly increases during the course of each fastening cycle, the "feel" of the tool is somewhat irregular. Therefore, there is a need for a multi-stroke fastening device having a uniform stroke length.
Prior art fastening devices that drive a fastener into a workpiece with a single blow need not be concerned with the fastener driver maintaining a coupled relation with respect to the fastener being driven. Multi-blow fastening devices, on the other hand are presented with a unique problem in that if a plurality of fastening impacts are to be imparted upon a single fastener to drive the fastener into the workpiece, the tool tends to bounce off the fastener head with each drive stroke. This may lead to an inefficient and rather clumsy operation of the tool.
Typical multiple blow fastening devices are pneumatically operated, therefore there has been little concern to conserve power. A battery operated fastening device is a lot more mobile and requires less equipment and assembly to operate than pneumatically operated devices. Therefore, there is a need for a fastening device that is battery operated and is constructed and arranged to conserve power during a fastening operation.
Power fastening devices for driving nails into a workpiece come in a variety of types. The fasteners used in such fastening devices vary according to the application. Most fasteners are made from a steel material. It is known in the art that the diameter of the fastener shank has a bearing on the strength of the connection provided. Basically, the greater the shank diameter, the greater the securing function provided.
For certain applications, such as in, pneumatically operated framing nailers, it has been known that the framing nails can be coated with a thermoplastic material that partially liquifies while the nails are being driven and then acts as an adhesive when the thermoplastic again solidifies after the nails are driven into the workpiece.
The adhesive nature of the thermoplastic is advantageous for certain applications because it increases the strength of the connection without requiring enlargement of the metal shank diameter. An ancillary benefit to providing the thermoplastic coating is that it reduces the energy required to drive the nail into the workpiece.
A disadvantage of providing a thermoplastic coating onto fastening nails is that it significantly increases the cost of manufacture in comparison with the same nails that are not so coated.
Roofing nails, which typically have a shank diameter of about 0.120".+-.0.0015" and a head diameter of about 0.350"-0.438", are typically used to fastener shingles onto a roof. Heretofore, roofing nails have not been coated because the shank and head dimensions are sufficiently large to provide a relatively strong connection, particularly in light of the typically relatively soft shingle material that often tears before the nails would be pulled out. The cost of coating roofing nails has been considered to far outweigh any benefit to be gained.
Through experimentation with the unique fastening device described herein, applicants have recognized that in the particular application of a battery operated roofing fastener assembly, conservation of energy (i.e., battery life) is critical. Therefore, although roofing nails provide a more than adequate securement of shingles without the need for coating the same, and although thermoplastic coating significantly adds to the cost of manufacture, applicants have determined that the amount of increase in battery life results from providing coated roofing nails warrants the added cost for this particular application.
In order to remove jams and repair fastening devices, it is necessary to remove the nose assembly of the fastener assembly. Typically, the nose assembly is fastened to the housing and requires tools to disassemble, thus increasing downtime. Therefore, there is a need for a fastening device which facilitates quick and easy removal of the nose assembly to remove jams, thus reducing downtime.
Because the fasteners of fastening devices are typically collated by a flexible collation material, the leading fastener tends to pivot about the collation material, as the fastener is driven into the workpiece, until the collation fractures. Substantial movement can disorient the fastener in the drive track. This may cause the fastener to be deformed and/or driven into the workpiece incorrectly. Therefore, there is a need to adjust the orientation of the fastener while the fastener is being driven into the workpiece.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a multi-stroke fastening device for driving fasteners into a workpiece. This multi-stroke fastening device provides a housing, a fastener drive track carried by the housing, a striker assembly guide track mounted within the housing, a striker assembly mounted in slidable relation within said guide track, a power drive assembly, and a feed mechanism. The striker assembly includes a driver member constructed and arranged to strike a fastener disposed in the fastener drive track. The striker assembly is constructed and arranged to be moved along the guide track through a plurality of alternating drive strokes and return strokes to effect a plurality of impacts of the driver member upon the fastener in order to drive the fastener into the workpiece. The striker assembly has a substantially constant drive stroke length relative to the guide track. The power drive assembly is constructed and arranged to drive the striker assembly to effect the plurality of impacts of the driver member upon the fastener, and the feed mechanism is constructed and arranged to feed successive fasteners into the drive track to be struck by the striker assembly.
It is also an object of the invention to provide a multi-stroke fastening device which includes a striker assembly having a drive stroke length which does not progressively increase as the fastener is progressively driven into the workpiece.
It is a further object of the present invention to provide a multi-stroke fastening device for driving fasteners into a workpiece, comprising a housing, a striker assembly guide track mounted within the housing, and a striker assembly mounted in slidable relation with respect to the guide track. The striker assembly includes a driver member constructed and arranged to strike a fastener to be driven into a workpiece. The striker assembly is moveable along the guide track through a plurality of alternating drive strokes and return strokes to effect a plurality of impacts of the driver member upon the fastener. Each drive stroke has substantially the same length. A power drive assembly is constructed and arranged to drive the striker assembly through the plurality of alternating drive strokes and return strokes to effect the plurality of impacts of the driver member upon the fastener. A nose assembly is carried by the housing and defines a fastener drive track along which the driver travels during the drive strokes and return strokes. Furthermore, a fastener head engaging structure is constructed and arranged to engage a portion of the head of the fastener to be driven at least during the return stroke. A resilient structure is operatively coupled to the fastener head engaging structure. The resilient structure is constructed and arranged to permit limited longitudinal movement of the fastener head engaging structure relative to the striker assembly guide track, and dampens impact of engagement between the fastener head engaging structure and the head of the fastener to be driven.
It is a further object of one embodiment of the present invention to provide a multi-stroke fastening device that employs a fastener impacting driver assembly that is coupled to the driving structure so that impacts of the driver assembly are very effectively damped to reduce vibrations and shock in the system. In accordance with this object, the present invention provides a multi-stroke fastening device for driving fasteners into a workpiece, comprising a housing. The nose assembly is carried by the housing and defines a drive track. A mechanical fastener feed mechanism includes a fastener feed pawl that moves successive fasteners into the drive track. A cylinder guide track is mounted within the housing, the cylinder guide track having a forward end and a rearward end. A driver assembly is disposed in slidably sealed relation with the cylinder guide track, the driver assembly being movable forwardly through the cylinder drive track during a fastener impacting drive stroke thereof and movable rearwardly through the cylinder guide track during a return stroke thereof. The driver assembly includes a driver member movable through the drive track during alternating drive strokes and return strokes to impart a plurality of impacts upon a fastener to be driven into the workpiece so as to drive the fastener into the workpiece. A piston is disposed in slidably sealed relation with the cylinder guide track, the piston being rearwardly spaced from the driver assembly, with an air space disposed between the piston and driver assembly. A motor is operatively connected with the piston and constructed and arranged to drive the piston forwardly and rearwardly through the cylinder guide track to effect the alternating drive strokes and return strokes. Movement of the piston forwardly through the cylinder guide track compresses air within the air space so as to force the driver assembly forwardly through the cylinder guide track to effect the fastener impacting drive stroke so that the driver member impacts the fastener to be driven.
It is a further object of the present invention to provide a fastening device that employs a manually operated feed assembly so that energy may be conserved. In accordance with this object, the present invention provides a fastening device for driving a fastener into a workpiece comprising a housing and a striker assembly movably mounted within the housing. The striker assembly includes a driver assembly adapted to strike the fastener to be driven into the workpiece. A nose assembly is operatively connected to the housing. The nose assembly has a fastener drive channel along which the driver assembly and the fastener travel when the fastener is driven into the workpiece. A mechanical feed assembly is operatively connected to the nose assembly for advancing a fastener into the fastener drive channel at a predetermined time. The feed assembly advances the fastener into the fastener drive channel in response to an application of a mechanical force on the nose assembly.
The present invention is directed to a fastening device for driving a fastener into a workpiece having a housing, and a striker assembly movably mounted within the housing. The fastening device also includes a magazine constructed and arranged to carry a coil of collated fasteners. In accordance with the present invention, the nose assembly includes a feed assembly constructed and arranged to advance a lead fastener within the coil of collated fasteners in response to manually generated movement of the nose assembly into the housing during a fastener driving operation. The nose assembly also includes a spring that biases the nose assembly outwardly from the housing. The spring is compressed in response to the manually generated movement of the nose assembly into the housing.
It is a further object of the present invention to provide a fastening device having an energy control assembly to control the operation of the device so that energy may be conserved. In accordance with this object, the present invention provides a fastening device for driving a fastener into a workpiece comprising a housing and a striker assembly movably mounted within the housing. The device includes an energy control assembly for controlling the operation of the fastening device. The energy control assembly controls the operation of the fastener device in order to conserve power and extend battery life.
The energy control assembly may include an actuator that terminates operation of the fastening device when actuated. The actuator is actuated in response to the nose assembly being moved a selected distance inwardly with respect to the housing. The energy control assembly further includes an adjuster assembly constructed and arranged to adjust the position of the actuator and hence adjust the selected distance which the nose assembly must move in order to actuate the actuator and thereby terminate operation of the fastening device.
It is a further object of the present invention to provide a fastening device having a nose releasing assembly to facilitate the removal of the nose assembly. In accordance with this object, the present invention provides a fastening device for driving at least one fastener into a workpiece comprising a housing and a striker assembly movably mounted within the housing. A nose assembly is releasably secured to the housing and has a fastener drive track along which the driver assembly and the at least one fastener travel when the at least one fastener is driven into the workpiece. The device includes a nose releasing assembly for releasably securing the nose assembly to the housing. The releasable fastener assembly permits easy removal of the nose assembly from the fastening device in the event of a fastener jam.
The present invention is also directed to fastening device for driving a fastener into a workpiece having a housing, a striker assembly movably mounted within the housing, a nose assembly releasably secured to the housing, and a manually operable nose releasing assembly constructed and arranged to releasably secure the nose assembly to the housing. The releasing assembly including a manually engageable release member being manually movable from a latched position to a released position.
It is a further object of the present invention to provide a fastening device that includes at least one guide surface for adjusting the orientation of the fastener while the fastener is being driven into the workplace. In accordance with this object, the present invention provides a fastening device for driving a fastener into a workpiece comprising a housing and a striker assembly movably mounted within the housing. A nose assembly is releasably secured to the housing and has a fastener drive channel along which the driver assembly and the fastener travel when the fastener is driven into the workpiece. The fastener drive channel terminates at an aperture in one end of the nose assembly through which the fastener passes as the fastener is driven into the workpiece. The fastener drive channel includes at least one guide surface adjacent the aperture to control the movement of the fastener within the guide channel.
The present invention is also directed to a multi-stroke fastening device for driving a fastener within a coil of collated fasteners into a workpiece. The fastening device comprising a housing, a striker assembly movably mounted within the housing, and nose assembly operatively connected to the housing. The nose assembly has a fastener drive channel along which the driver assembly and the fastener travel when the fastener is driven into the workpiece. The fastening device also includes a magazine assembly constructed and arranged to engage at least one fastener within the coil of fasteners in order to move a lead fastener within the coil of fasteners in a first direction toward the fastener drive channel. The lead fastener has a forward pointed end thereof tending to be moved in a second direction opposite the first direction in response to a rearward head end thereof being impacted by the driver assembly due to the interconnection of the collation material between the lead fastener and a subsequent fastener. In accordance with the present invention, the nose assembly includes an angled guide surface constructed and arranged to engage the tip of the lead fastener as it is being driven. The guide surface is angled so as to direct the tip of the lead fastener toward the first direction as the lead fastener is being driven.
In accordance with an embodiment of the present invention, the nose assembly further comprises a pivoted guide structure defining a pivoted guide surface disposed in opposing relation to the angled surface. The pivoted guide structure is biased towards a first position such that pivoted structure is disposed adjacent to the angled guide surface so that the pivoted guide surface and the angled guide surface form a fastener outlet which is dimensioned to be smaller than a head of the fastener. In operation, the head of a fastener engages the pivoted guide surface as the fastener is being driven so as to force the pivoted guide structure away from the angled guide surface against the spring bias to enable the outlet to be sufficiently sized to permit the fastener head to pass therethrough. The angled guide surface and the pivoted guide surface guidably engaging the head as the head passes thereby.
It is a further object of the present invention to provide coated nails to facilitate driving of the nails into the workpiece so that energy may be conserved. In accordance with this object, the present invention provides a coil of collated roofing nails comprising a plurality of collated roofing nails interconnected by a collation material. Each of the nails has a shank portion with a shank diameter of about 0.120".+-.0.0015" and a head portion with a head diameter of about 0.350" to 0.438". Each of the nails is coated with a thermoplastic material that serves as a lubricant which facilitates driving of the nails into a workpiece so as to reduce the energy required to drive the nails into the workpiece.
These and other objects, features, and advantages of this invention will become apparent from the following detailed description when taken in conjunction with the accompanying drawings, which are a part of this disclosure and which illustrate, by way of example, the principles of this invention.
BRIEF DESCRIPTION OF THE DRAWINGS
The present invention will be described in conjunction with the following drawings in which like reference numerals designate like elements and wherein:
FIG. 1 is a cross-sectional view of a multi-stroke fastening device in accordance with a first embodiment of the present invention illustrating the fastening device at the start of its drive stroke;
FIG. 2 is a cross-sectional view of the multi-stroke fastening device in accordance with the first embodiment of the present invention illustrating the fastening device mid-way through its drive stroke;
FIG. 2A is a cross-sectional view of the multi-stroke fastening device in accordance with the first embodiment of the present invention illustrating the fastening device during its return stroke;
FIG. 3 is a cross-sectional view of the multi-stroke fastening device in accordance with the first embodiment of the present invention illustrating the fastening device as it completes its drive stroke;
FIG. 4 is a cross-sectional view of the multi-stroke fastening device in accordance with the first embodiment of the present invention illustrating the fastening device in its reset position;
FIG. 5 is a cross-sectional view of the multi-stroke fastening device in accordance with a second embodiment of the present invention illustrating the fastening device at the start of its drive stroke;
FIG. 6 is a cross-sectional view of the multi-stroke fastening device in accordance with the second embodiment of the present invention illustrating the fastening device mid-way through its drive stroke;
FIG. 6A is a cross-sectional view of the multi-stroke fastening device in accordance with the second embodiment of the present invention illustrating the fastening device during its return stroke;
FIG. 7 is a cross-sectional view of the multi-stroke fastening device in accordance with the second embodiment of the present invention illustrating the fastening device as it completes its drive stroke;
FIG. 8 is a cross-sectional view of the multi-stroke fastening device in accordance with the second embodiment of the present invention illustrating the fastening device in its reset position;
FIG. 9A is a cross-sectional view of the multi-stroke fastening device in accordance with a third embodiment of the present invention;
FIG. 9B is an enlarged view of circled section B in FIG. 9A;
FIG. 10 is an enlarged view of the head of the fastener device illustrated in FIG. 9;
FIG. 11 is a sectional view taken through line 11--11 in FIG. 9A;
FIG. 12 is an enlarged cross-sectional view of the multi-stroke fastening device in accordance with the third embodiment of FIG. 9A illustrating the fastening device at rest;
FIG. 13 is a cross-sectional view of the multi-stroke fastening device in accordance with the third embodiment of FIG. 9A illustrating the fastening device at an initial stage of operation;
FIG. 14 is an enlarged partial sectional view of the multi-stroke fastening device in accordance with the third embodiment of FIG. 9A illustrating the fastening device at the end of a fastening operation;
FIG. 15 is a side view of a multi-stroke fastening device in accordance with a fourth embodiment of the present invention;
FIG. 16 is a cross-sectional side view of the multi-stroke fastening device of FIG. 15;
FIG. 17 is a cross-sectional top view of the multi-stroke fastening device of FIG. 15;
FIG. 18 is an end view of the multi-stroke fastening device of FIG. 15;
FIG. 19 is a partial schematic of one side of the mechanical feed mechanism, nose assembly, and drive assembly in accordance with the embodiment of FIG. 15;
FIG. 20 is a partial schematic of an opposite side of the mechanical feed mechanism, nose assembly, and drive assembly in accordance with the embodiment of FIG. 15;
FIG. 21 is a cross-sectional view of the multi-stroke fastening device of FIG. 15 in a reset position;
FIGS. 22-25 are cross-sectional views of the multi-stroke fastening device of FIG. 15 illustrating the operation of driving a fastener into the workpiece;
FIG. 26 is a schematic view of the multi-stroke fastening device of FIG. 15 having a portion of the housing removed;
FIG. 27 is a schematic view of the nose assembly and feed assembly of the multi-stroke fastening device of FIG. 15 removed from the housing of the multi-stroke fastening device and in an open position;
FIG. 28 is an overhead view of the nose releasing assembly in accordance with the embodiment of FIG. 15;
FIGS. 29-32 are schematic views illustrating the operation of the nose releasing assembly of FIG. 15 as the nose assembly is inserted into the housing of the multi-stroke fastening device;
FIGS. 33-40 are partial cross-sectional views illustrating the operation of the angled guide surface and pivoted guide surface of the nose assembly as the fastener is driven into the workpiece by the multi-stroke fastening device in accordance with the present invention;
FIGS. 41-46 are schematic views illustrating the operation of the energy control assembly of the multi-stroke fastening device of FIG. 15 as the nose assembly retracts into the housing as the fastener is driven into the workpiece;
FIG. 47 is a schematic view illustrating the construction of the locking mechanism and the angled guide surface in accordance with the present invention;
FIGS. 48-52 are schematic views illustrating the operation of the gripping arms and locking mechanism of the feed assembly of the multi-stroke fastening device of FIG. 15 as the fastener is driven into the workpiece and subsequent fastener is fed into the fastener drive channel; and
FIG. 53 is a schematic view of a coil of collated fasteners and fastener dispensing assembly in accordance with the present invention.
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a cross-sectional view of a multi-stroke fastening device 10 in accordance with the first embodiment of the present invention. FIG. 1 illustrates the device 10 at rest, with a first fastener 33 in the drive track 14.
The fastening device 10 has an outer clam-shell housing 12, preferably made from a rigid plastic material. A fastener drive track 14 is carried by the housing 12. In the particular embodiment shown, the drive track 14 is provided by a movable nose assembly 16, which has a lower longitudinal slot 17 for receiving fasteners to be positioned in the drive track 14. The nose assembly 16 is movable axially into the housing 12 in a direction along the fastener driving axis. More particularly, a nose receiving channel 18 is fixed within the housing 12 towards the forward end of the housing 12. The nose receiving channel 18 is preferably provided with a grooved track that receives projecting flanges integrally formed on opposite sides of the nose assembly 16 so that the channel 18 slidably receives the nose assembly 16, the nose assembly being biased outwardly of the nose receiving channel 18 by a coil spring 20. The coil spring 20 has a rearward end bearing against a mounting plate 22 fixed within the housing 12 and a forward end bearing against the rearward end of the nose assembly 16, thus biasing the nose assembly 16 forwardly towards a forward stop position thereof.
A striker assembly guide track 26 is fixed within the housing 12. In the embodiment shown in FIG. 1, the guide track is a cylindrical, metal tubular member, conventionally termed a "cylinder." It is contemplated, however, that for other arrangements in accordance with the principles of the present invention, the guide track can be any structure which slidingly guides a striker assembly for impact and return strokes. The guide track 26 has an annular resilient bumper 28, preferably made from an elastomeric material such as rubber, disposed towards the forward end of the guide track 26. It is contemplated that other elastomeric materials may be utilized to form the bumper 28.
A striker assembly 30 is mounted in slidable relation within the guide track 26. The striker assembly 30 includes a driver member 32 which is constructed and arranged to strike a fastener 33, which is the leading fastener within a group of collated fasteners 34. The collated fasteners 34 comprise a plurality of fasteners fixed to one another by a substantially rigid collation 36. As shown, the leading fastener 33 is disposed within the drive track 14.
The striker assembly 30 is movable axially along the guide track 26 through a plurality of alternating drive strokes and return strokes to effect a plurality of impacts of the driver member 32 upon the fastener 33 for driving the fastener 33 into a workpiece W. The driver member 32 extends through an opening within the mounting plate 22 and further extends through the center of coil spring 20 and is received at its forward end within an opening in the rearward end of the nose assembly 16 to be received in the drive track 14 for impacting upon the fasteners. The opening in mounting plate 22 and/or opening in the rearward end of nose assembly 16 maintains the driver member in axially aligned relation with the drive track 14 and hence, lead fastener 33.
The striker assembly 30 further comprises a plunger 40 to which the driver is connected. The plunger 40 has a substantially disc-shaped rearward end portion 42 having a peripheral annular groove for receiving a generally annular sealing member 44 disposed in slidable and sealed relation with an interior cylindrical surface 46 of the guide track 26.
As will be described in greater detail later, the striker assembly 30 has a substantially constant drive stroke length relative to its guide track 26. While the drive stroke may vary slightly, for example, as a result of slightly different resistances to the fastener being driven into a particular workpiece at progressive depths of the fastener, it should be appreciated that the drive stroke length does not progressively increase as the fastener 33 is progressively driven into the workpiece W, as is the case with prior art constructions.
A power drive assembly 50 is constructed and arranged to drive the striker assembly 30 to effect a plurality of impacts of the driver member 32 upon fastener 33. Preferably, the power drive assembly includes a piston 52, having a generally cylindrical outer configuration, and an outer periphery having a sealing member 54 disposed in slidable and sealed relation with the inner surface 46 of the guide track 26, in similar fashion to sealing member 44. The power drive assembly 50 further includes a crank member 56 rotatable about an axis 58. More specifically, the crank member 56 is mounted to a crank mounting assembly 60, which is fixed to the guide track 26. An axis pin 58 is attached to the mounting 60 and mounts the crank 56 for rotational movement. A crank arm 62 is pivotally connected at opposite ends thereof, including a first end 64 pivotally connected to the piston 52, and opposite end 66 pivotally connected with the crank 56. Thus, rotation of the crank 56 causes reciprocating motion of the piston 52 within the guide track 26.
The crank 56 includes a pulley 70 disposed on the periphery thereof and is constructed and arranged to receive a drive belt 72. The drive belt is driven by a motor 74, which rotatably drives the crank 56 via the belt 72. Rather than a pulley and belt arrangement, a gear train or other coupling arrangement could be employed.
The motor 74 is switched on and off by a control circuit 76, which includes a trigger switch, which is activated by a manually actuated trigger 78, and preferably also includes a nose switch, which is activated by a contact trip that is engaged when the nose assembly is retracted into the tool housing. The control circuit 76 is connected with a power supply assembly, preferably including a power source in the form of a battery 80, and most preferably, a rechargeable battery. The battery 80 has a battery contact 82, which can be removed from housing contacts 84 to enable the battery 80 to be recharged and/or replaced. It should be appreciated that other power sources may be used for powering the power drive assembly 50. For example, the device may be connected with line voltage, an air pressure supply where the device is pneumatically driven, combustion power, or other suitable power supplies.
A feed mechanism 90 is constructed and arranged to feed successive fasteners within the supply of collated fasteners 34 into the drive track 14 to enable the successive fasteners to be struck by the striker assembly 30. More particularly, the feed mechanism 90 is cooperable with a feed track 92, which is integrally cast with the nose assembly 16. The feed track 92 feeds the collated fasteners 34 into the drive track 14 through the longitudinal slot 17 in the nose assembly 16. The feed mechanism 90 includes a movable feed pawl 96. The feed pawl 96 is pivotable about its rearward end portion 98, which is provided with a torsion spring 100 constructed and arranged to biased feed pawl 96 in a clockwise direction (as viewed in FIG. 1) about the rearward end portion 98. The rearward end 98 of the feed pawl 96 rides along a ramped surface 102 as the nose assembly 16 moves relative to the housing 12. The feed pawl 96 further has a more forward portion thereof pivotably connected to the feed track 92 to establish somewhat of a connecting rod type motion for the feed pawl 96 as the nose assembly 16 is moved relative to the housing 12 and the rearward end portion 98 of the feed pawl 96 rides along the ramp surface 102. As a result of this connecting rod type motion, the forward end portion of the feed pawl 96 is able to feed individual fasteners into the drive track 14 as will be appreciated from the more detailed description of the operation of the device 10 to follow.
In FIG. 1, the device 10 is shown at rest prior to a fastening operation. The collated fasteners 34 are manually manipulated up through the feed track 92, so that the first two fasteners are moved beyond the feed pawl 96, which can be manually moved out of the feed track 92 for initial loading purposes. As shown, the first fastener 33 is positioned in the drive track 14. Preferably, with the tool at rest, the forward tip of the first fastener 33 projects slightly forwardly of the fully extended forward end of the nose assembly 16, as shown. This preferred arrangement enables the user to view the tip of the fastener 33 and position the tip at a very precise location. To view the leading fastener 33 even more clearly, it is possible to manually move the nose assembly 16 inwardly into the housing 12 against the bias of coil spring 20 to reveal a greater portion of the fastener 33 for positioning the tip at a precise location.
After the tip of fastener 33 is placed against the workpiece W, the operator depresses trigger 78, thereby closing the trigger switch in circuit 76 to provide power from the battery 80 to the motor 74. The motor 74 drives the belt 72, which in turn causes rotation of the crank 56. Rotation of the crank 56 causes reciprocal movement of the piston 52 through the connection of the piston 52 with the crank 56 via connecting arm 62. Reciprocal movement of the piston 52 within the guide track 26 causes corresponding reciprocal movement of the striker assembly 30.
More particularly, the power drive assembly 50 is resiliently coupled to the striker assembly 30 via a substantially sealed airspace 110 between the piston 52 and the rearward end portion 42 of plunger 40, as shown in FIG. 1. More specifically, driving piston 52 forwardly towards the plunger 40 tends to reduce the distance between the piston 52 and the plunger 40. Because airspace 110 between piston 52 and plunger 40 is substantially sealed, the airspace 110 will be pressurized during the forward stroke of the piston 52. This pressurization of airspace 110 biases the plunger 40 forwardly, away from the piston 52, so as to maintain the volume of the sealed airspace 110 within a predetermined range. Thus, it can be appreciated that the pressurization of airspace 110 drives the plunger 40, and hence the entire striker assembly 30 forwardly, so that the driver member 32 impacts upon the head of the fastener 33. This action can be seen in FIG. 2. It should be appreciated that the initial impact of the driver member 32 releases the fastener 33 from the collation 36.
While in FIG. 2, the fastener 33 is shown having approximately two-thirds of its length driven into the workpiece W, it should be appreciated that this would typically be accomplished only after a plurality of impacts or blows upon the fastener head 33. At the bottom or end of each impact drive stroke, the plunger 40 preferably impacts the resilient bumper 28 at the forward end of the guide track 26. It should be appreciated, however, that for certain individual strokes (e.g., towards the end of a fastening operation where extreme forces may be required to finish driving the last bit of the fastener into the workpiece) and/or certain applications (e.g., for particularly hard workpieces) the resistance of the fastener 33 being driven into the workpiece W may serve to stop the movement of the striker assembly 30 prior to the plunger 40 impacting on the bumper 28. It should be appreciated, however, that it is preferred for the plunger 40 to contact the bumper 28 for every stroke for a more consistent operation of the device. In the instance in which the plunger 40 does not contact the bumper 28, it would terminate its forward stroke movement just short of the bumper 28, with minimal spacing therebetween (e.g., less than 5 mm apart). Hence, it can be appreciated that the total impact drive stroke length is fairly constant for each impact stroke.
After each impact stroke, the striker assembly 30 is drawn rearwardly within the guide track 26 as a result of its being resiliently coupled to the power drive assembly 50. More particularly, as the piston 52 is withdrawn within the guide track 26 by the action of crank 56, a vacuum is created in the substantially sealed airspace 110 so as to draw the plunger 40 rearwardly with the piston 52. This can be appreciated from FIG. 2A, where the plunger 40 is shown being drawn rearwardly relative to an impacting position as shown in FIG. 2.
It should be appreciated that the resilient coupling provided by the airspace 110 substantially cushions the driving impact of the striker assembly 30 upon fastener 33. This reduces vibration of the tool and provides for a quieter operation. In addition, after the striker assembly is pulled back by the vacuum in space 110, and the piston 52 instantaneously reverses direction so as to commence forward movement, a pressure pulse or spike in generated in airspace 110, thus creating high levels of kinetic energy for driving the striker assembly forwardly. The airspace 110 in effect acts as an airspring.
It should also be appreciated that because the vibrations of the tool are reduced, the life of the tool 10 can be increased, and the user experiences less fatigue from use of the tool as a result.
The volume of the airspace 110 remains within a predetermined range during the continuous cycling of the device, such that the piston 52 and plunger 40 remain within a predetermined range of distance therebetween. It can be appreciated that towards the end of an impact stroke, the volume of airspace is somewhat reduced after the piston 52 bottoms out on the bumper 28. The volume of airspace is then somewhat increased when the piston is pulled away from the bumper 28 during the return stroke. Similarly, the volume is decreased towards the end of the return stroke as a result of the momentum in the rearward direction of striker assembly 30 and then the instantaneous reversal of direction of the piston into the forward direction. The volume of the airspace 110 is a function of the mass of striker assembly 30, speed of the striker assembly 30, stroke length of the striker assembly 30, among other things. Preferably, the airspace is connected with an overpressurization and underpressurization bleed valve (not shown). Thus, if at any time pressure within the airspace is above or below threshold levels, air will bleed into or out of the airspace to maintain the pressure therein within a predetermined range.
It is desirable to make the striker assembly 30 sufficiently lightweight so that it follows the travel of the piston 52 for each stroke and does not become out of phase with movement of the power drive assembly 50. It is also desirable for the striker assembly to impart as much of its energy as possible to the fastener to be driven, and experience as little rebound as possible. In such manner, a sufficiently large vacuum can be drawn in airspace 110, so that for each stroke the vacuum serves to pull the striker assembly 30 rearwardly, and in phase with the power drive assembly 50, as opposed to rebound of the striker assembly adding a variable that may cause the striker assembly to be forced out of phase with the power drive assembly.
The power drive assembly 50 and striker assembly 30 continue to cycle as described above until the fastener 33 is eventually driven completely into the workpiece W. It should be appreciated that a plurality of impacts is required to drive the fastener into a typical workpiece W, such as wood. For example, it is contemplated that between about five to fifty impact strokes might be used to drive a fastener into a workpiece, depending on the application. It is also contemplated that the power drive assembly 50 would be capable of driving the striker assembly at a rate of about forty to seventy cycles or impact strokes per second, depending upon the application.
As the fastener 33 is driven into the workpiece W, the nose assembly 16 is progressively retracted into the tool housing 12 against the bias of coil spring 20. This action is largely a result of the forward manual force applied by the operator. When the device 10 is used to fasten a horizontal surface, with the nose assembly 16 pointing downwardly (e.g., wood flooring), the weight of the device 10 also assists in movement of the nose assembly into the housing 12 against the force of coil spring 20.
When the fastener 33 is completely embedded in the workpiece W, the nose assembly 16 reaches a point at which it is fully retracted within the nose receiving channel 18. In a preferred embodiment, when the nose assembly reaches this point, the nose assembly 16 engages a contact trip (not shown) which trips a nose switch (that can be included as part of circuit 76) to shut off motor 74 and terminate cycling of the power drive assembly 50 and striker assembly 30. This feature is described in greater detail in connection with the description of the embodiment of FIG. 15. The device 10 can then be pulled away from the workpiece W. As the device 10 is pulled away from the workpiece W, the nose assembly 16 is permitted to extend outwardly from the nose receiving channel 18 and hence, outwardly from the housing 12 under the force of coil spring 20. As the nose assembly 16 is forced outwardly of the nose receiving channel 18, it releases the nose contact trip that shut down motor 74. In a preferred embodiment, circuit 76 will not enable the motor 74 to be energized again until after the nose switch or nose contact trip is released and after the trigger 78 is released and then subsequently depressed again. Alternately, a second contract trip may be provided, and this second contact trip would be activated once the nose assembly 16 reaches the forwardmost position thereof. Activation of the second contact trip would reactivate the motor 74. In this way, the trigger 78 can remain depressed by the operator, and movement of the nose assembly 16 between its fully extended and fully retracted positions would be the means by which to shut off and restart motor 74 between fastening operations. It is desirable for the motor to shut down between fastening operations in order to conserve the power source 80, especially where that source is in the form of a battery.
Shown in the FIGS. 2, 2A, and 3, as the rearward end 98 of the feed pawl 96 rides up the ramp surface 102 as the nose assembly 16 is retracted into the nose receiving channel 18, the pawl 96 becomes positioned behind the third fastener 114. When the rearward end 98 of the feed pawl 96 is permitted to ride back down the ramp surface 102 as the nose assembly 16 is forced outwardly of the nose receiving channel 18 after a fastening operation, the forward end of the feed pawl 96 is fully positioned behind the third fastener 114, and the spring bias of torsion spring 100 acting through pawl 96 on the third fastener 114, moves the entire collation of fasteners 34 upwardly so that the second fastener 116 is moved through the slot 17 in the nose assembly 16 and into the drive track 14. The fastener 116 is now in position to be driven in subsequent fastening operations, as illustrated in FIG. 4.
Opening 120 is disposed in the upper portion of the nose assembly 16 for receiving the used collation 36. Similarly, openings 123 and 125 are provided in the nose receiving channel 18 and the housing 12, respectively, to similarly accommodate the spent collation (not shown). Where the collation 36 is made from a paper material (as opposed to plastic or metal), it may not be necessary to provide for any exit thereof, as it will be substantially disintegrated.
FIGS. 5-8 illustrate a second embodiment of the multi-stroke fastener device in accordance with the principles of the present invention, generally indicated at 130. Operation of the second embodiment is quite similar to that of the first embodiment, and hence, corresponding components are illustrated with the same reference numerals as in the first embodiment. The differences between the first embodiment and this second embodiment will be described with particularity.
In accordance with the second embodiment of the present invention, the fastening device 130 employs an array of collated fasteners 134, but preferably utilizes a more flexible collation 136 to connect the fasteners to one another. The collation 136 and the heads of the fasteners are manipulated through a longitudinal slot in the top of clam shell housing 140. As shown, a first fastener 142 is disposed in the drive track 144. The fastener 142 is driven essentially in the same fashion as described with respect to fastener 33 in the embodiment of FIGS. 1-4. At the completion of a fastening operation (as illustrated in FIG. 7), movement of the nose assembly 146 into its retracted position within the nose receiving channel 148 causes the nose contact trip or switch to be tripped, thereby causing circuit 76 to terminate operation of the motor 74 and hence, the power drive assembly 50. When the device 130 is pulled away from the workpiece W (see FIG. 8), a feed mechanism 160 is actuated (either by release of the first contact trip or by use of a second contact trip activated by movement of the nose assembly 146 to its extended position). The feed mechanism 160 comprises a ratchet wheel 162. Preferably, the ratchet wheel 162 has a plurality of radially extending prongs 164, which are resiliently biased outwardly via internal springs to project outwardly from a main wheel portion 166 of the feed mechanism. The prongs 164 are constructed and arranged such that engagement thereof by a structure running circumferentially or tangentially to the periphery of wheel portion 166 in one direction will move the prongs 164 inwardly, while engagement thereof in an opposite direction will not, as will be appreciated more fully from the following further description. Although not shown, the ratchet wheel 162 is connected by a gear train to the nose assembly 146, as can be appreciated by those skilled in the art. When the nose assembly 146 is retracted during a fastener driving operation, the ratchet wheel 162 is rotated in a clockwise direction as viewed in FIGS. 5-8. During this clockwise rotation, the radially extending spring biased members 164 have convex cam surfaces that are permitted to ride over the head of the next fastener 170 and are forced inwardly against the internal spring bias thereof. In contrast, when the nose assembly 146 is extended from the nose receiving channel 148 after a fastener driving operation, the ratchet wheel 162 is rotated in a counter-clockwise direction (relative to the FIGS. shown). With this action, concave catching surfaces of the resiliently biased projections 164 engage the head of the next fastener 170 and drive the same into the drive track 144 for the next fastening operation.
In accordance with the second embodiment, the front end of the device 130 can be made somewhat smaller in comparison with that of the first embodiment.
FIG. 9A is a cross-sectional view of a third embodiment of a multi-blow fastening device, generally indicated at 200, in accordance with the principles of the present invention. FIG. 9B is an enlarged view of circled section B in FIG. 9A. The device 200 is the same in many respects as the device illustrated in FIG. 1. For example, the multi-blow fastening device 200 has a housing 212, a cylindrical striker assembly guide track 226, piston 252 within the cylindrical track 226, plunger 240 connected with a driver member 232, airspace 210, crank arm 262, crank 256, pulley 270, belt 272, motor 274, feed mechanism 290, an elastomeric bumper 228, and a battery 280, all as described above with respect to the first embodiment, and need not be repeated here. Driver member 232 together with plunger 240 constitute what may be termed a striker assembly or driver assembly 230, a forward position of which is shown in phantom lines and a rearward position of which is shown in partial cross section. The piston 252 is shown in its rearward position only. It will be appreciated by those skilled in the art that other specific details of the embodiments of FIGS. 1-8 (such as with respect to an exit for the spent collation) may also be applied to the embodiments of FIGS. 9-18 and not be repeated here. The device of 200 differs from the first embodiment most significantly towards the front end of the device 200 that interfaces with the fasteners to be driven.
Specifically, the device 200 includes a nose assembly 216 mounted in the housing 212. The nose assembly 216 preferably includes a channel-like nose member 261 which is spring biased forwardly by a coil spring member 220. The nose member 261 receives collated fasteners 234 through a lower slot 217 in the nose member 261. The nose member 261 of the nose assembly defines a drive track along which the forward end of driver 232 travels during the drive strokes and return strokes.
The nose member 261 is mounted for longitudinal, axial sliding movement within a nose receiving channel member 263. More specifically, as shown best in FIG. 11, which is a sectional view taken through the line 11--11 in FIG. 9A, the nose receiving channel member 263 is provided with a pair of nose guide members 266 extending laterally inwardly openings 299 through the housing 212, and threadedly received in threaded bores in the side wall of the channel member 263. The forward ends of guide members 266 are received in respective grooves or channels 268 formed in opposite sides of the nose member 261. The engagement of guide members 266 with channels 268 enable the nose member 261 to be slidably mounted within channel member 263. The length of channels 268 limits the longitudinal travel of the nose member 261.
As can be appreciated from FIG. 12, the nose receiving channel 263 is a generally cylindrical tubular structure, preferably having a portion of its circumference (preferably about 50.degree.) cut-away towards the forward bottom portions thereof to enable the nose receiving channel 263 to receive the lower feed track portion 206 of nose member 261 as it moves rearwardly into the tool against the force of spring 220 during a fastener driving operation. The nose receiving channel 263 may also be provided with one or more longitudinally extending interior tracks or ribs 273 that cooperate with corresponding tracks or ribs (not shown) on the external surface of the nose member 261 so that the nose member 261 can slide in controlled fashion relative to the channel 263.
As can be seen best in FIG. 10, the nose receiving channel member 263 is fixed to the housing 212 and also has its rearward end fixed to the forward end of the striker assembly guide track 226 by appropriate fasteners 271 extending through respective abutting annular flanges 202,204 of the guide track 226 and of the nose receiving channel 263, respectively. The preferred guide track 226, as with the previous embodiments, is a cylindrical tubular structure and has an air vent 227 towards the forward end thereof (see FIG. 10) that vents displaced air from in front of the plunger 240.
The connection between the nose receiving channel 263 with the striker assembly guide track 226 also serves to secure a mounting structure 265. Specifically, as best seen in FIG. 10, which is an enlarged sectional view of a portion of FIG. 9A, an annular recess 275 is formed in the rear end of nose receiving channel member 263 to receive an annular flange 277 of the mounting structure 265. The mounting structure 265 has a main cylindrical portion 279 extending axially in parallel relation to the nose receiving channel 263. The forward end of the mounting structure 265 has a radially inwardly projecting flange 281, which terminates in slidable abutting relation with the cylindrical outer surface of a fastener head engaging structure 267. More specifically, the fastener head engages structure 267 is generally tubular member having a rearward end telescopingly received in the mounting structure 265. The forward end portion of fastener head engaging structure 267 is received within an axial bore 208 in the nose member 261, as seen in FIG. 12.
Referring back to FIG. 10, a radially outwardly projecting flange 283 at the rear end of the fastener head engaging structure 267 has a forward surface thereof abutting against the flange 281 of the tubular mounting structure 265 so that the rear end of the fastener head engaging structure 267 is retained within the mounting structure 265.
The fastener head engaging structure 267 acts as a guide tube for the driver member 232 received therethrough. The fastener head engaging structure 267 also serves to engage the head of a fastener being driven and to maintain the fastener in spaced relation, at a predetermined spaced distance, from the guide track 226 throughout a drive stroke.
As shown in FIG. 9B, the cylindrical portion 279 of the mounting structure 265 has a diameter which is sufficiently large so as to be radially outwardly spaced from the driver 232. Disposed within this space is a resilient elastomeric tubular structure 269 generally cylindrical in shape. The forward annular edge of the resilient structure 269 engages the rearward surface of the annular flange 283 of fastener head engaging structure 267. The rearward annular edge of the resilient structure 269 engages the forwardly facing surface of the resilient bumper 228. Preferably, the resilient structure 269 is formed from a rubber-based material, as is the bumper 228.
It is contemplated that the resilient structure 269 may be integrally formed/molded with the bumper 228.
As best seen in FIG. 10, the resilient structure 269 is operatively coupled to the fastener head engaging structure 267 (by being engaged therewith) to permit limited longitudinal movement of the fastener head engaging structure 267 relative to the striker assembly guide track 226. The resilient structure 269 is constructed and arranged to dampen the engagement (and any slight impact) between the forward end of the fastener engaging structure 267 and the head of a fastener being driven (see FIGS. 13 and 14). Specifically, the resilient structure 269 is longitudinally compressed or stressed by the fastener head engaging structure 267 under the force and weight of the tool bearing upon the fastener being driven (see FIG. 14). When the driver member 232 impacts the head of the fastener with each stroke, the head of the fastener being driven may become slightly forwardly spaced from the forward, annular fastener engaging surface 209 of the fastener head engaging structure 267. When the driver member 232 is retracted, the force of gravity acting on the device 200 and/or the application of force by the user to the device 200 maintains the forward edge 209 of the fastener head engaging structure 267 in contact with the head of the fastener being driven. Any slight impacts between the forward edge 209 and the head of the fastener being driven are damped by the resilient structure 269.
FIG. 12 illustrates the device 200 at rest, prior to cycling of the driver member 232, and with a fastener 233 disposed in the drive track 214. The nose member 261 is in its fully extended position under the force of coil spring 220. FIG. 13 illustrates an initial stage of tool operation, i.e., the user has pulled the trigger and has forced the forward end of nose member 261 against a workpiece W to compress spring 220 a predetermined distance to activate a nose switch 292 connected with a control circuit that commences cycling of the plunger 240 and driver 232. The feed mechanism 290 has a roller 291 that rides along a track 294 as the nose element 261 is forced against a workpiece and moves into the housing 212 against the bias of coil spring 220. When the roller 291 reaches a contact portion 292 of a nose switch, which contact portion is disposed along the track 294, control circuitry within the tool causes motor 274 is energized to commence cycling of the tool. The nose switch contact portion 292 is illustrated schematically, and the electrical connection between the nose switch contact portion 292 and motor 274 is not shown, nor is the control circuit shown in detail, as those skilled in the art will appreciate that these types of elements and connections can be one of several different known constructions and still fall within the scope the present invention. When the nose switch contact trip 292 remains depressed, the tool continues to cycle. When the roller 291 rides past the mechanical contact portion 292 after the nose assembly is forced into the housing (which in the embodiment shown is in the form of an elongated button) the control circuit sends a signal to shut down the motor (or in a contemplated embodiment, first slows down the motor to a fraction of its duty cycle before completely shutting the motor down).
As the tool is subsequently pulled away from the workpiece, the nose assembly is permitted to project outwardly from the housing, and the roller rides down a different, adjacent return path, which is parallel to the surface 294 so that it does not depress contact portion 292 on its return as the nose is extended out from the housing after a fastening operation. This can be accomplished by a cross-over railroad track type intersection.
As an alternative to an elongated contact portion 292, the roller 291 may be provided with a cam follower that maintains engagement with a smaller contact portion 292 as the nose assembly is moved into the housing, but releases the contact portion once the nose assembly is moved fully into the housing. In any event, the contact portion remains depressed until the nose assembly is substantially fully received within the housing, at which point the contact portion is released to permit the circuit and motor to terminate the fastening cycle.
As the roller 291 rides up ramp 295 of the track 294 as the tool is pressed against a workpiece to commence a fastening operation, the feed mechanism 290 pivots about a pivot 296 to enable a feed pawl (also not shown) to engage the collated fasteners 234 and move a lead fastener 233 into the drive track 214. As shown in FIG. 13, the plunger 240 has commenced its initial retraction within the guide track 226, however, it should be appreciated that the present embodiment contemplates that initial movement of the plunger 240 need not commence at this stage. Rather, it is possible to design the tool such that it only commences cycling after the nose member 261 is sufficiently moved rearwardly within the tool a sufficient distance such that the forward point of fastener 233 engages workpiece W. FIG. 14 is an enlarged partial sectional view similar to FIG. 11, but illustrates the device 200 towards the end of a fastening operation.
The resiliency of the resilient structure 269, the length of driver member's 232 forward extension beyond the forward end of fastener head engaging structure 267 during the drive stroke, the downward force applied when using the tool, among other factors, may have a bearing on the separation between the head of the fastener being driven and the forward surface 209 of the fastener head engaging structure 267. In any case, it should be appreciated that the resiliency of the resilient structure 269 minimizes the distance of, or can practically eliminate the disengagement between the fastener head engaging structure 267 and the head of the fastener being driven during the drive and return strokes. That is, when the forward end of the driver member 232 extends forwardly of the fastener contacting forward edge of fastener head engaging structure 267, the resiliency of the resilient structure 269 enables the fastener contacting edge of the fastener head engaging structure 367 to remain closely coupled with or remain only slightly spaced from the head of the fastener with each stroke. The resilient structure 269 is compressed slightly during each return stroke under the weight (force) of the tool, and decompresses slightly at the end of each drive stroke to maintain the close engagement between the fastener head engaging structure 267 and the head of the fastener being driven.
By providing the resilient structure coupled with fastener head engaging structure, the operation of the tool becomes much smoother and vibrations are effectively damped, thus eliminating tool bounce off the fastener.
The fastener head engaging structure 267 maintains the head of the fastener being driven spaced a predetermined distance relative to the guide track 226, which distance varies essentially only as a function of the resilience of the resilient structure 269. Preferably, the resilient structure 269 is made from a urethane material, which is the same urethane material that forms bumper 228.
In the embodiment specifically described and shown, the fastener head engaging structure 267 is formed as a separate structure from the nose assembly 216. It is contemplated, however, that the fastener head engaging structure 267 may constitute part of the nose assembly 216 in alternate embodiments contemplated by this invention.
FIGS. 15-53 illustrate a fourth embodiment of a multi-stroke fastening device 300 in accordance with the present invention for driving a fastener 333 into a workpiece, generally shown at W.
The device 300 includes a housing 312, as shown in FIG. 15. A nose assembly 316 is movably mounted within a portion of the housing 312 at a forward portion thereof. The nose assembly 316 has a fastener drive track 314, or also referred to as a fastener drive channel, along which a driver assembly, generally shown at 330, and the fastener 333 travel when the fastener 333 is driven into the workpiece W, as shown in FIGS. 21-25.
A striker assembly 324 is movably mounted within the housing 312. The striker assembly 324 refers to the combination of the driver assembly 330 and a power drive assembly 350, as shown in FIGS. 16, 17 and 21-25. The striker assembly 324 is adapted to strike the fastener 333 to be driven into the workpiece W and comprises, among other things, a driver member 332 and a plunger 340. Like the embodiments described above, the striker assembly 324 contacts the fastener 333 multiple times during a fastening operation to drive the fastener 333 into the workpiece W. The power drive assembly 350 is constructed to drive the driver assembly 330 and comprises a piston 352, a crank member 356, a crank arm 362, and a gear train, generally shown at 370, as shown in FIGS. 16, 17, 19 and 20.
The striker assembly 324 has a guide track 326, preferably made from metal, which has a forward end and a rearward end. It, however, is contemplated that other materials such as for example a plastic having similar properties may be used. The guide track 326 has an annular resilient bumper 328, preferably made from an elastomeric material such |