Hydraulic actuator

The present invention provides a hydraulic actuator adapted for use in downhole well applications that enables control of several hydraulic devices from a single control line.

 

We claim:

1. A hydraulic distributor, comprising:

(a) an inlet connected to a hydraulic control line supplying hydraulic fluid pressure,

(b) at least one primary outlet and at least one secondary outlet, and

(c) a valve having a first position in which the hydraulic fluid pressure is restricted from the at least one primary outlet, and having a second position in which the hydraulic fluid pressure is restricted from the at least one secondary outlet, the valve maneuverable between its first position and its second position by the hydraulic fluid pressure.

2. The hydraulic distributor of claim 1, wherein the hydraulic fluid pressure controls one or more hydraulic devices.

3. The hydraulic distributor of claim 2, wherein the one or more hydraulic devices are selected from sleeve valves, ball valves, packers, formation isolation valves, gas lift valves, locks, sliding sleeves, and hydraulic distributors.

4. The hydraulic distributor of claim 2, wherein the hydraulic distributor is provided in a wall of the one or more hydraulic devices.

5. The hydraulic distributor of claim 2, wherein the hydraulic devices are part of a tool string.

6. The hydraulic distributor of claim 5, wherein the hydraulic distributor is provided in a wall of the tool string.

7. The hydraulic distributor of claim 1, wherein the valve is moved between its first and second positions by a mandrel.

8. The hydraulic distributor of claim 7, wherein the mandrel is manipulated by hydraulic pressure.

9. The hydraulic distributor of claim 7, wherein the mandrel is manipulated mechanically.

10. The hydraulic distributor of claim 7, further comprising an indexer assembly moveable through a plurality of positions to manipulate the mandrel.

11. The hydraulic distributor of claim 7, further comprising a lock assembly to fixedly engage the mandrel.

12. A hydraulic distributor, comprising:

(a) an inlet port adapted for receipt of hydraulic pressure,

(b) one or more first outlet ports and one or more second outlet ports,

(c) a valve, and

(d) a mandrel having a first position and a second position, the mandrel affixed to the valve such that, with the mandrel in its first position, the valve restricts the hydraulic pressure to the one or more first outlet ports and with the mandrel in its second position, the valve restricts the hydraulic pressure to the one or more second outlet ports, the mandrel moveable between its first position and its second position by the hydraulic pressure.

13. The hydraulic distributor of claim 12, wherein the hydraulic pressure controls one or more hydraulic devices.

14. The hydraulic distributor of claim 13, wherein the one or more hydraulic devices are selected from sleeve valves, ball valves, packers, formation isolation valves, gas lift valves, locks, sliding sleeves, and hydraulic distributors.

15. The hydraulic distributor of claim 13, wherein the hydraulic distributor is provided in a wall of the one or more hydraulic devices.

16. The hydraulic distributor of claim 13, wherein the hydraulic devices are part of a tool string.

17. The hydraulic distributor of claim 16, wherein the hydraulic distributor is provided in a wall of the tool string.

18. The hydraulic distributor of claim 12, wherein the mandrel is manipulated mechanically.

19. The hydraulic distributor of claim 12, further having a lock assembly hydraulically activated to fixedly engage the mandrel.

20. The hydraulic distributor of claim 12, further having an indexing assembly for manipulating the mandrel.

21. A hydraulic distributor, comprising:

(a) a housing defining an inlet and a plurality of outlets,

(b) a valve moveably positioned in the housing adapted to selectively close the plurality of outlets, and

(c) a pressure responsive indexer connected to the valve adapted to control the position of the valve.

22. The hydraulic distributor of claim 21, wherein the pressure responsive indexer has a mandrel affixed to the valve.

23. The hydraulic distributor of claim 22, wherein the pressure responsive indexer has a lock assembly to fixedly engage the mandrel.

24. The hydraulic distributor of claim 22, wherein the pressure responsive indexer has an indexer assembly to manipulate the mandrel.

25. The hydraulic distributor of claim 22, wherein the pressure responsive indexer is activated mechanically.

26. A hydraulic distributor, comprising:

(a) a housing defining an inlet connected to a hydraulic control line and at least one outlet, the inlet adapted for receipt of pressurized fluid from the hydraulic control line;

(b) a valve moveably positioned in the housing adapted to selectively close the at least one outlet to selectively control the flow of pressurized fluid from the inlet to the at least one outlet; and

(c) an indexer connected to the valve adapted to control the position of the valve in response to the pressurized fluid.

27. The hydraulic distributor of claim 26, wherein the at least one outlet is in communication with the one or more hydraulic devices.

28. The hydraulic distributor of claim 27, wherein the one or more hydraulic devices are selected from sleeve valves, ball valves, packers, formation isolation valves, gas lift valves, locks, sliding sleeves, and hydraulic distributors.

29. The hydraulic distributor of claim 27, wherein the hydraulic distributor is provided in a wall of the one or more hydraulic devices.

30. The hydraulic distributor of claim 27, wherein the hydraulic devices are part of a tool string.

31. The hydraulic distributor of claim 30, wherein the hydraulic distributor is provided in a wall of the tool string.

32. The hydraulic distributor of claim 26, wherein the valve is moveably positioned by a mandrel.

33. The hydraulic distributor of claim 32, wherein the mandrel is manipulated by hydraulic pressure.

34. The hydraulic distributor of claim 32, wherein the mandrel is manipulated mechanically.

35. The hydraulic distributor of claim 32, further comprising an indexer assembly moveable through a plurality of positions to manipulate the mandrel.

36. The hydraulic distributor of claim 32, further comprising a lock assembly to fixedly engage the mandrel.

37. A method of distributing a hydraulic fluid, comprising:

(a) providing a pressure responsive toggle valve having an inlet and a plurality of outlets;

(b) changing the pressure supplied to the inlet to shift the toggle valve to selectively close at least one of the plurality of outlets.

38. A method of providing hydraulic fluid pressure from a single source to a plurality of hydraulic devices, the method comprising:

(a) providing a hydraulic distributor having an inlet port and one or more first outlet ports and one or more second outlet ports,

(b) supplying hydraulic fluid pressure to the inlet port sufficient to activate the hydraulic distributor to prevent the flow of hydraulic fluid pressure to the one or more first outlet ports,

(c) varying the hydraulic fluid pressure supplied to the inlet port to activate the hydraulic distributor to prevent the flow of hydraulic fluid pressure to the one or more second outlet ports.

39. A system for distributing a hydraulic fluid, comprising:

(a) a hydraulic control line;

(b) a distributor having an inlet in fluid communication with the hydraulic control line;

(c) the distributor comprising at least two outlets and a valve moveable in the distributor to control the flow from the inlet to the at least two outlets;

(d) the valve shiftable in response to pressure supplied to the inlet.

40. The system of claim 39, wherein the valve is mechanically shiftable.

41. A system for distributing a hydraulic fluid, comprising:

(a) a hydraulic control line;

(b) a first distributor having at least one inlet, at least one first outlet, and at least one second outlet, the at least one inlet in communication with the hydraulic control line;

(c) a second distributor having at least one inlet, at least one first outlet, and at least one second outlet, the at least one inlet in communication with the at least one first outlet of the first distributor, the at least one first outlet in communication with a first hydraulic device, and the at least one second outlet in communication with a second hydraulic device; and

(d) a third distributor having at least one inlet, at least one first outlet, and at least one second outlet, the at least one inlet in communication with the at least one second outlet of the first distributor, the at least one first outlet in communication with a third hydraulic device, and the at least one second outlet in communication with a fourth hydraulic device.

42. A system for distributing a hydraulic fluid, comprising:

(a) a hydraulic control line;

(b) a first distributor having at least one inlet, at least one first outlet, and at least one second outlet, the at least one inlet in communication with the hydraulic control line, and the at least one first outlet in communication with a first hydraulic device; and

(c) a second distributor having at least one inlet, at least one first outlet, and at least one second outlet, the at least one inlet in communication with the at least one second outlet of the first distributor, the at least one first outlet in communication with a second hydraulic device, and the at least one second outlet in communication with a third hydraulic device.

43. A system for distributing a hydraulic fluid, comprising:

(a) a hydraulic control line;

(b) a first distributor having at least one inlet, at least one first outlet, and at least one second outlet, the at least one inlet in communication with the hydraulic control line;

(c) a second distributor having at least one inlet, at least one first outlet, and at least one second outlet, the at least one inlet in communication with the at least one first outlet of the first distributor, the at least one first outlet in communication with a hydraulic device, and the at least one second outlet in communication with the hydraulic device; and

(d) a third distributor having at least one inlet, at least one first outlet, and at least one second outlet, the at least one inlet in communication with the at least one second outlet of the first distributor, the at least one first outlet in communication with the hydraulic device, and the at least one second outlet in communication with the hydraulic device.

44. A system for distributing a hydraulic fluid, comprising:

(a) a hydraulic control line;

(b) a first distributor having at least one inlet, at least one first outlet, and at least one second outlet, the at least one inlet in communication with the hydraulic control line;

(c) a second distributor having at least one inlet, at least one first outlet, and at least one second outlet, the at least one inlet in communication with the at least one first outlet of the first distributor, the at least one first outlet in communication with a first hydraulic device, and the at least one second outlet in communication with the first hydraulic device; and

(d) a third distributor having at least one inlet, at least one first outlet, and at least one second outlet, the at least one inlet in communication with the at least one second outlet of the first distributor, the at least one first outlet in communication with a second hydraulic device, and the at least one second outlet in communication with a third hydraulic device.

FIELD OF THE INVENTION

The present invention relates to well completion equipment, and more specifically to mechanisms for actuating downhole well tools that require pressurized hydraulic fluid to operate.

BACKGROUND OF THE INVENTION

It is well known that many downhole devices require power to operate, or shift from position to position in accordance with the device's intended purpose. A surface controlled subsurface safety valve (SCSSV) requires hydraulic and/or electrical energy from a source located at the surface. Setting a packer that is sealably attached to a string of production tubing requires either a tubing plug together with application of pressure on the tubing, or a separate and retrievable "setting tool" to actuate and set the packer in the tubing. Sliding sleeves or sliding "side door" devices may also require hydraulic activation. It will become apparent to anyone of normal skill in the art that many downhole devices requiring power for actuation can be adapted to utilize this invention. Such devices may comprise: packers, such as those disclosed in U.S. Pat. Nos. 5,273,109, 5,311,938, 5,433,269, and 5,449,040; perforating equipment, such as disclosed in U.S. Pat. Nos. 5,449,039, 5,513,703, and 5,505,261; locking or unlocking devices, such as those disclosed in U.S. Pat. Nos. 5,353,877 and 5,492,173; valves, such as those disclosed in U.S. Pat. Nos. 5,394,951 and 5,503,229; gravel packs, such as those disclosed in U.S. Pat. Nos. 5,531,273 and 5,597,040; flow control devices or well remediation tools, such as those disclosed in U.S. Pat. Nos. 4,429,747, and 4,434,854; and plugs or expansion joints, of the type well known to those in the art.

Each of these well known devices has a method of actuation, or actuation mechanism that is integral and specific to the tool. Consequently, in the past, most of these well known devices have required an independent source of power. There is a need for a device that can provide one or more sources of pressurized hydraulic fluid into the downhole environment, enabling actuation of any number of downhole tools. The device should be adaptable for various downhole tasks in various downhole tools, and be simple to allow for redress in the field. It should also be adaptable for permanent installation in the completion, thereby allowing multiple functions to be performed on multiple tools located therein, all controlled by an operator at a control panel on the earth's surface.

BRIEF DESCRIPTION OF THE INVENTION

A full understanding of the present invention will be obtained from the detailed description of the preferred embodiment presented herein below, and the accompanying drawings, which are given by way of illustration only and are not intended to be limitative of the present invention, and wherein:

FIG. 1 is a cross-sectional view of an embodiment of the hydraulic distributor of the present invention.

FIG. 2 is a cross-sectional view of the seating element and seal nut of an embodiment of the hydraulic distributor.

FIG. 3 is a perspective view of an embodiment of the indexer sleeve of the present invention in its lowermost position.

FIG. 3A is a diagrammatic sketch of the receptacles of the indexer sleeve of the present invention.

FIG. 4 is a cross-sectional view of an embodiment of the hydraulic distributor of the present invention in its first position under no pressure.

FIG. 5 is a cross-sectional view of an embodiment of the hydraulic distributor of the present invention in its first position under an initial pressure.

FIG. 6 is a cross-sectional view of an embodiment of the hydraulic distributor of the present invention in its first position under an elevated pressure.

FIG. 7 is a cross-sectional view of an embodiment of the hydraulic distributor of the present invention in its first position with the elevated pressure bled off.

FIG. 8 is a cross-sectional view of an embodiment of the hydraulic distributor of the present invention in its first position with the initial pressure bled off.

FIG. 9 is a cross-sectional view of an embodiment of the hydraulic distributor of the present invention transitioning to its second position under no pressure.

FIG. 10 is a cross-sectional view of an embodiment of the hydraulic distributor of the present invention in its second position under an initial pressure.

FIG. 11 is a cross-sectional view of an embodiment of the hydraulic distributor of the present invention in its second position under an elevated pressure.

FIG. 12 is a cross-sectional view of an embodiment of the hydraulic distributor of the present invention in its second position with the elevated pressure bled off.

FIG. 13 is a cross-sectional view of an embodiment of the hydraulic distributor of the present invention transitioning to its first position with the initial pressure bled off.

FIG. 14 is a sectional view of an embodiment of the present invention in which hydraulic fluid pressure is distributed to upper and lower pistons.

FIG. 15 is a diagrammatic sketch of an embodiment of the present invention wherein the hydraulic distributor further comprises a ratchet assembly.

FIG. 15A is a perspective view an embodiment of the present invention wherein the ratchet assembly further comprises a mechanical override.

FIG. 15B is a perspective view of the proximal components of an embodiment of the mechanical override.

FIG. 15C is a perspective view of the distal components of an embodiment of the mechanical override.

FIGS. 15D and 15E show an embodiment of the present invention used to control a subsurface safety valve. FIG. 15D provides a perspective view wherein the ratchet assembly is shown in a cut-away cross sectional view, and FIG. 15E provides a cross-section taken along line 15E in FIG. 15D.

FIG. 15F is a perspective view of an embodiment of an internal brake.

FIG. 16 is a diagrammatic sketch of an embodiment of the present invention wherein the hydraulic distributor is used to control a sliding sleeve valve.

FIGS. 17A-17D are fragmentary elevational views, in quarter section, of an embodiment of the present invention wherein the hydraulic is used to control a safety valve.

FIGS. 18A and 18B are longitudinal sectional views, with portions in side elevation, of an embodiment of the present invention wherein the hydraulic distributor is used to control a subsea control valve apparatus.

FIGS. 19A and 19B are elevational views, of an embodiment of the present invention wherein the hydraulic distributor is used to control a variable orifice gas lift valve.

FIG. 20 is a diagrammatic sketch of an embodiment of the present invention wherein the hydraulic distributor is used to control a hydraulically actuated lock pin assembly.

FIG. 21 is a cross-sectional view of an embodiment of the present invention wherein the hydraulic distributor is used to control a resettable packer.

FIGS. 22A-22D are continuations of each other and are elevational views, in quarter section, of an embodiment of the present invention wherein the hydraulic distributor is used to control a safety valve.

FIGS. 23A-23B are sectional views of an embodiment of the present invention wherein the hydraulic distributor is used to control a formation isolation valve.

FIGS. 24A-24C are continuations of each other and form an elevational view in cross section of an embodiment of the present invention wherein the hydraulic distributor is used to advantage to control an emergency disconnect tool.

FIG. 25 is a diagrammatic sketch of a series of hydraulic distributors used to control a plurality of tools from a single control line. FIG. 25A is a diagrammatic sketch of a series of hydraulic distributors used to control a plurality of tools from a single control line.

FIG. 25B is a diagrammatic sketch of a series of hydraulic distributors used control a single tool from a single control line.

FIG. 25C is a diagrammatic sketch of a series of hydraulic distributors used control a plurality of tools from a single control line.

DETAILED DESCRIPTION OF THE INVENTION

In the following detailed description of the subject matter of the present invention, the invention is principally described as being used in oil well applications. Such applications are intended for illustration purposes only and are not intended to limit the scope of the present invention. The present invention can also be used to advantage in operations within gas wells, water wells, injection wells, control wells, and other applications requiring remote hydraulic control. All such applications are intended to fall within the purview of the present invention. However, for purposes of illustration, the present invention will be described as being used for oil well applications.

Additionally, in the following detailed description of the subject matter of the present invention, the invention is principally described as being used to supply hydraulic devices with hydraulic fluid pressure from a main control line. Such hydraulic devices include, but are not limited to, hydraulic tools, hydraulic actuators, and hydraulic distributors, for example. All such applications are intended to fall within the purview of the present invention.

In describing the present invention and its operation, it is important to note that directional terms such as "up", "down", "upper", "lower", are used to facilitate discussion of the example. However, the present invention can be used to advantage in any axially orientation. However, for purposes of illustration, certain directional terms relating to the orientation on the drawing page will be used. FIG. 1 is a cross-sectional view of an embodiment of the hydraulic distributor 1 of the present invention. The main body 10 of the hydraulic distributor 1 serves as its chassis and comprises a flow control housing 12 and an actuator housing 52 that are in coupled communication to channel the hydraulic fluid pressure from the main control line 18. It should be noted that although in this embodiment of the present invention the main body 10 is a unitary component having two housings 12, 52, in alternate embodiments within the scope of the present invention, the main body 10 can be comprised of other configurations such as, for example, separate, but affixed housings 12, 52.

Hydraulic fluid pressure from the main control line 18 is received by an inlet port 14 in the flow control housing 12. In this embodiment of the hydraulic distributor 1, the inlet port 14 has a series of inlet threads 16 for sealingly engaging the nozzle of the main control line. However, there are a multiplicity of ways in which the main control line can engage the inlet port 14 of the flow control housing 12 such as flanged connections, quick-connect fittings, welded connections, and the like. All such ways are intended to fall within the purview of the present invention. The flow entering the inlet port 14 is distributed to a plurality of outlet ports 20a, 20b. The outlet ports 20a, 20b provide the conduit for supplying hydraulic fluid pressure to hydraulic devices.

In an embodiment of the present invention, each outlet port 20a, 20b houses a seating element 22 that controls the flow therethrough the outlet ports 20a, 20b. Each seating element 22, in this embodiment, is maintained within the outlet ports 20a, 20b by a seal nut 32.

It should be noted that in alternate embodiments, the seating element 22 is maintained within the outlet ports 20a, 20b by means such as welds, solders, threaded connections, or the like. In still further alternate embodiments, the seating element 22 is integral with the outlet ports 20a, 20b.

As best described with reference to FIG. 2, each seating element 22 provides a seating surface 24 that is a mating surface for a spring-controlled actuation ball 38 (discussed below) to redirect fluid communication. When the actuation ball 38 is in mating contact with the seating surface 24, fluid is prevented from entering and traveling through the internal conduit 26 that extends therethrough the seating element 22. Conversely, when the actuation ball 38 is not in mating contact with the seating surface 24, fluid may flow through the internal conduit 26. In an alternate embodiment, the seating surface 24 is energized by a spring, for example, to further secure the mating engagement with the actuation balls 38.

At the distal end of the internal conduit 26 is a tool interface port 28 that provides the interface to supply fluid flow from the internal conduit 26 to the hydraulic devices. The tool interface port 28 is provided with internal threads 30 for engagement with the attached hydraulic devices. However, alternate connections for engagement may be utilized depending upon the type of hydraulic device. Such connections include, but are not limited to, flanged connections, quick-connect fittings, welded connections, and the like. All such ways are intended to remain within the purview of the present invention.

Referring back to FIG. 1, the flow control housing 12 is further defined by a control chamber 34. The control chamber 34 is an internal channel within the flow control housing 12 that extends from the inlet port 14 to the outlet ports 20a, 20b and extends from the inlet port 14 to the actuator housing 52. Housed within the control chamber 34 is a supply alternator 36. The supply alternator 36 controls the distribution of the hydraulic fluid pressure from the inlet port 14 to the appropriate outlet port 26a, 26b.

In the embodiment of FIG. 1, the supply alternator 36 is comprised of a ball housing 40 that houses a plurality of actuation balls 38, ball springs 44 and spring spacer 46. The ball housing 40 is oriented within the control chamber 34 such that it is axially aligned with the longitudinal axis of the seating elements 22. The ball housing 40 has a retaining shoulder 42 at each distal end of the ball housing 40. Intermediate within the ball housing 40 is the spring spacer 46 that acts as a base for the opposing ball springs 44 that bias the actuation balls 38 towards each retaining shoulder 42. The retaining shoulders 42 prevent further outward movement of the actuation balls 38.

A plurality of control screws 48 are affixed to and extend therefrom the ball housing 40 in a direction perpendicular to the axial orientation of the ball housing 40. To maintain the spacing and orientation of the control screws 48, a control screw spacer 50 is provided from which the control screws 48 extend therefrom. The control screws 48 extend from the ball housing 40 and are affixed to a shuttle sleeve 60 (discussed below) housed within the actuator housing 52. Although shown as screws, the "control screws 48" may be any member capable of connecting the ball housing 40 to the shuttle sleeve 60. For example, the "control screws 48" can be an arm, an integrally formed connector, or any other connection.

The actuator housing 52 has a locking end 76, an indexing end 112, and defines an internal bore 54. The internal bore 54 is defined by the interior walls 56 of the actuator housing 52 and extends therethrough the actuator housing 52. The internal bore 54 is further defined by a bore shoulder 58.

A shuttle sleeve 60 having a lock end 62 and an index end 70 resides within the internal bore 54 such that the shuttle sleeve 60 can travel axially therethrough. The lock end 62 of the shuttle sleeve 60 provides a shuttle sleeve spring 64 within a shuttle spring housing 66. The lock end 62 further provides a locking profile 68 that is defined by a series of recesses 69a, 69b. The index end 70 provides a base surface 72 that abuts the bore shoulder 58 to limit the travel of the shuttle sleeve 60 towards the indexing end 112 of the actuator housing 52.

The shuttle sleeve 60 further provides a control screw receptacle 74 for fixed engagement with the control screws 48 originating in the supply alternator. Because of the substantially rigid fixation, movement of the shuttle sleeve 60 controls the movement of the supply alternator 36.

A lock piston housing 78 is affixed to the locking end 76 of the actuator housing 52. The lock piston housing 78 has a lock piston chamber 80 defined by opposing interior walls 82 and a chamber base 84. In an alternate embodiment, a spacer (such as stack of washers) is located on the chamber base 84.

A lock piston 88 is located and maneuverable within the lock piston chamber 80. The lock piston 88 is comprised of a piston rod 90, a flange 92, and a control rod 94. The lock piston further comprises a piston shaft 90a that enables external manipulation of the lock piston 88 (as will be discussed below). A lock piston seal 110 maintains the fluid pressure within the lock piston chamber 80. It should be noted that the lock piston seal 110 shown in FIG. 1 is exemplary of one embodiment of the present inventionAny number of seal arrangements could be utilized to advantage in the present invention. To fall within the purview of the present invention it is only necessary that the seal arrangement act to prevent loss of fluid within the actuator housing 52.

The control rod 94 of the lock piston 88 extends from the flange 92 opposite the piston rod 90. The control rod 94 has a tapered detent 96 utilized to manipulate a plurality of locking balls 108 as will be discussed below. The distal end of the control rod 94 extends within the lock end 62 of the shuttle sleeve 60.

A lock spring 98 located within the lock piston chamber 80 is utilized to bias the lock piston rod 90 away from the chamber base 84. The lock spring 98 applies biasing force against the flange 92 of the lock piston rod 90. The stroke of the lock piston rod 90 away from the chamber base 84 is limited, and defined by, the location of a fixed cage 100. The fixed cage 100 having a limiting shoulder 102 is affixed to the interior walls 82 of the lock piston chamber 80. The limiting shoulder 102 resists movement of the piston rod 90 resulting from the bias of the lock spring 98 when the flange 92 abuts the limiting shoulder 102. Thus, the stroke of the lock piston rod 90 is controlled by the location of the fixed cage 100.

The fixed cage 100 further has a lock ball housing 104. The lock ball housing 104 extends within the lock end 62 of the shuttle sleeve 60 and receives of the control rod 94 of the lock piston 88 therethrough. The lock ball housing 104 defines a plurality of receptacles 106 for the receipt of the lock balls 108. The lock ball housing 104 provides the base for the shuttle sleeve spring 64 located within the shuttle sleeve spring housing 66.

As will be discussed further below, the relational positions of the control rod 94, the lock ball housing 104, and the lock balls 108 control whether the shuttle sleeve 60 is engaged by the fixed cage 100 thereby preventing axial movement by the shuttle sleeve 60. As shown in FIG. 1, the shuttle sleeve 60 is in an unlocked position in which the lock balls 108 are not engaging the recesses 69a, 69b of the shuttle sleeve 60, but are rather residing within the tapered detent 96 of the control rod 94. However, it should be understood that downward (with respect to the drawing page) axial movement of the control rod 94 will result in the lock balls 108 being forced out of the tapered detent 96 of the control rod 94 and into engagement with one of the recesses 69a, 69b of the shuttle sleeve 60, thereby preventing the shuttle sleeve 60 from further axial movement. Upon an upward movement by the control rod 94, the lock balls 108 release from engagement with the shuttle sleeve 60 and again reside in the tapered detent 96 of the control rod 94.

An indexer piston housing 114 is affixed to the indexing end 112 of the actuator housing 52. The index piston housing 114 has an indexer piston chamber 116 defined by opposing interior walls 118 and a chamber base 120. In an alternate embodiment, a spacer (such as a stack of washers) is located on the chamber base 120.

An indexer piston 122 is located and maneuverable within the indexer piston chamber 116. The indexer piston 122 is comprised of a piston rod 124, a flange 126, and a control rod 128. An indexer piston seal maintains the fluid pressure within the indexer piston chamber 116. As discussed above with reference to the lock piston seal 110, it should be noted that the indexer piston seal 152 shown in FIG. 1 is exemplary of one embodiment of the present invention. Any number of seal arrangements could be utilized to advantage in the present invention. To fall within the purview of the present invention it is only necessary that the seal arrangement act to prevent loss of fluid within the actuator housing.

The control rod 128 of the indexer piston 122 extends from the flange 126 opposite the piston rod 124. The control rod 128 is utilized to manipulate the shuttle sleeve 60, as will be discussed below. The control rod 128 extends within the indexing end 112 of the actuator housing 52.

An indexer spring 130 located within the indexer piston chamber 116 is utilized to bias the indexer piston rod 124 away from the chamber base 120. The indexer spring 130 applies biasing force against the flange 126 of the indexer piston rod 124. The stroke of the indexer piston rod 124 resulting from the spring bias is limited, and defined by, the location of an indexer sleeve 134 with relation to an indexer pin 132.

The indexer sleeve 134 is housed within thrust bearings 150 and is affixed to the indexer piston 122 such that axial movement of the indexer piston 122 results in axial movement of the indexer sleeve 134 and vice versa. The axial displacement of the indexer sleeve 134 is limited by the indexer pin 132 that is rigidly affixed to the interior wall 118 of the indexer piston chamber 116.

The axial displacement of the indexer sleeve 134 is best described with reference to FIGS. 3, which is a perspective view of an embodiment of the indexer sleeve 134 of the present invention in its uppermost position, and FIG. 3A which is a diagrammatic sketch displaying the relational positions of the receptacles of the indexer sleeve. As shown in FIG. 3, the indexer sleeve 134 is comprised of an upper thrust surface 136, a lower thrust surface 138, one or more upper stops 140, one or more lower receptacles 144, and one or more intermediate receptacles 146.

In FIG. 3, the indexer pin 132 is located in a lower receptacle 144. In this position, the indexer pin 132 prevents the indexer sleeve 134 from upward movement resulting from a force applied to the lower thrust surface 138. However, upon application of force to the upper thrust surface 136 the indexer sleeve 134 is able to move downward toward its lowermost position. As the indexer sleeve 134 moves downward, the indexer pin 132 is forced into engagement with the tapered surface 142 of an upper stop 140 which forces the indexer sleeve 134 to rotate. The downward travel and rotation of the indexer sleeve 134 continues until the upper stop 140 is engaged by the indexer pin 132. At this point, the indexer sleeve 134 has rotated such that the indexer pin 132 is in axial alignment with the tapered surface 148 of an intermediate receptacle 146.

With the indexer sleeve in its lowermost position in which the indexer pin 132 is engaged by an upper stop 140, a force applied to the lower thrust surface 138 results in the indexer sleeve 134 moving upward toward its uppermost position. As the indexer sleeve 134 moves upward, the tapered surface 148 of an intermediate receptacle 146 engages the indexer pin 132. With continued upward movement, the indexer pin 132 forces the indexer sleeve 134 to rotate as it moves upward. The upward travel and rotation of the indexer sleeve 134 continues until the intermediate receptacle 146 is engaged by the indexer pin 132. At this point, the indexer sleeve 134 is prevented from returning to its uppermost position and is maintained in its intermediate position by the interaction between the indexer pin 132 and the intermediate receptacle 146. Further, the indexer sleeve 134 has rotated such that the indexer pin 132 is in axial alignment with the tapered surface 142 of an upper stop 140.

Alternate applications of force to the upper thrust surface 136 and the lower thrust surface 138 will continue to cause the indexer sleeve 134 to rotate and oscillate between a lowermost, uppermost, and intermediate position.

It should be noted that the positions of travel of the indexer sleeve 134 of this embodiment of the present invention are only demonstrative for a particular application. By altering the receptacle and slot arrangements of the indexer sleeve 134, the indexer sleeve 134 can be oscillated between any number of intermediate positions, or no intermediate positions at all (a simple 2 position indexer sleeve 12). All such embodiments fall within the purview of the present invention.

It should further be noted that in an alternate embodiment, the indexer pin 132 could be located on the control rod 128 with the positional receptacles of the indexer sleeve 134 held stationary within the indexer piston housing 114. Again, such embodiments are intended to fall within the purview of the present invention.

FIGS. 4-9 illustrate the various stages of operation of the hydraulic distributor 1 as it is switched from its first position to its second. FIG. 4 illustrates a cross-sectional view of an embodiment of the hydraulic distributor 1 in its upper position under no pressure. The indexer sleeve 134 in FIG. 4 is in an uppermost position with the indexer pin 132 engaged by a lower receptacle 144. The bias of the indexer spring 130 resists downward movement of the indexer sleeve 134 with the upper movement limited by the interaction between the indexer pin 132 and the lower receptacle 144. Under these conditions, the control rod 128 of the indexer piston 122 contacts the base surface 72 of the shuttle sleeve 60 and forces the shuttle sleeve 60 into its upper position and prevents the shuttle sleeve 60 from downward movement.

Under no pressure, the coefficient of the lock spring 98 is not overcome and so the lock spring 98 continues to maintain the lock piston 88 in its lowermost position in which the flange 92 abuts the fixed cage 100. With the lock piston 88 in its lowermost position, the lock balls 108 remain within the tapered detent 96 of the control rod 94 and the shuttle sleeve 60 is not fixed to the fixed cage 100. However, the downward movement of the shuttle sleeve 60 is restricted by the control rod 128 of the indexer piston 122 as discussed above. Thus, the shuttle sleeve 60 is locked in its upper position.

With the shuttle sleeve 60 in its upper position, the control screws 48, which are affixed to the shuttle sleeve 60, are forced into an upper position within the control chamber 34. Consequently, the supply alternator 36 is forced into its upper position in which the upper actuation ball 38 matingly engages the seating surface 24 of the upper seating element 22. Such engagement is secured by the force supplied by the compression of the upper ball spring 44. The lower actuation ball 38 is maintained within the ball housing 40 by the lower retaining shoulder 42.

The application of an initial pressure to the hydraulic distributor 1 is illustrated in FIG. 5. Under initial pressure, the hydraulic distributor 1 remains in its first position. It should be understood that for purposes of illustration, the term "initial pressure" refers to a pressure sufficient to overcome the spring coefficient of the lock spring 98, but insufficient to overcome the spring coefficient of the indexer spring 130. The coefficients are solely dependent upon the type of application for which the hydraulic distributor 1 is utilized.

As shown in FIG. 5, the hydraulic distributor 1 remains in its first position in which the shuttle sleeve 60 remains in its uppermost position with the indexer pin 132 engaged by a lower receptacle 144. The control rod 128 of the indexer piston 122 maintains the shuttle sleeve 60 in its upper position and resists downward movement of the shuttle sleeve 60.

Under initial pressure conditions, the coefficient of the lock spring 98 is overcome such that the flange 92 applies a force to the lock spring 98 sufficient to compress the lock spring 98 and enable the piston rod 90 to move upward (indicated by the arrow) toward the chamber base 84 of the lock piston chamber 80. The piston rod 90 continues to compress the lock spring 98 until movement of the piston rod 90 is resisted by the chamber base 84. In the embodiment shown in FIG. 5, to protect the surface of the chamber base 84, and to adjust the load of the lock spring 98, a spacer 86 is provided.

As the piston rod 90, and thus control rod 94, moves upward, the lock balls 108 are forced out of the tapered detent 96 and into engagement with the first recess 69a of the locking profile 68 of the shuttle sleeve 60. The shuttle sleeve 60 is consequently fixedly engaged to the fixed cage 100 and prevented from downward movement regardless of the position of the control rod 128 of the indexer piston 122.

With the shuttle sleeve 60 remaining in its upper position, the supply alternator 36 is maintained in its upper position in which the upper actuation ball 38 matingly engages the seating surface 24 of the upper seating element 22. The initial pressure is restricted from flow into the upper internal conduit 26 of the upper seating element 22 but is free to flow through the lower internal conduit 26 of the lower seating element 22. Thus, the initial pressure can be used to supply hydraulic fluid pressure to a hydraulic device attached to the lower seating element 22.

It should be understood that the term "restricted" as used herein to describe the control of flow through the upper and lower internal conduits 26 refers to a condition wherein the flow is totally or substantially prevented from entering the conduits 26. As long as a portion of the flow is prevented from entering the conduits 26, the flow is considered to be restricted.

FIG. 6 displays a cross-sectional view of hydraulic distributor 1 as the initial pressure is increased to an elevated pressure. Under this elevated pressure, the hydraulic distributor 1 still remains in its first position. It should be understood that for purposes of illustration, the term "elevated pressure" refers to a pressure sufficient to overcome the spring coefficient of the lock spring 98, and sufficient to overcome the spring coefficient of the indexer spring 130. Again, these coefficients are solely dependent upon the type of application for which the hydraulic distributor 1 is utilized.

As indicated by the arrows in FIG. 6, the coefficient of the indexer spring 130 is overcome such that the flange 126 of the indexer piston 122 applies a force to the indexer spring 130 sufficient to compress the indexer spring 130 and enable the piston rod 124 to move downward toward the chamber base 120. The action of the piston rod 124 forces the indexer sleeve 134 downward toward its lowermost position. As the indexer sleeve 134 moves downward, the indexer pin 132 engages the tapered surface 142 of an upper stop 140 which forces the indexer sleeve 134 to rotate. The downward travel and rotation of the indexer sleeve 134 continues until the upper stop 140 is engaged by the indexer pin 132. At this point, the indexer sleeve 134 has rotated such that the indexer pin 132 is in axial alignment with the tapered surface 148 of an intermediate receptacle 146.

With the upper stop 140 engaged by the indexer pin 132, the indexer sleeve 134 is in its lowest position. Consequently, the control rod 128 is also in its lowest position in which the control rod 128 does not extend above the bore shoulder 58. Thus, the control rod 128 of the indexer piston 122 no longer resists downward movement of the shuttle sleeve 60. However, because the lock piston 88 remains in its upper position with the lock balls 108 of the fixed cage 100 engaged with the recess 69a of the shuttle sleeve 60, the shuttle sleeve 60 is maintained in its upper position.

Once again, with the shuttle sleeve 60 remaining in its upper position, the supply alternator 36 is maintained in its upper position in which the elevated pressure is restricted from flow into the internal conduit 26 of the upper seating element 22 but is free to flow through the internal conduit 26 of the lower seating element 22. Thus, the elevated pressure can be used to supply hydraulic fluid pressure to a hydraulic device attached to the lower seating element 22.

FIG. 7 illustrates the hydraulic distributor 1 with the elevated pressure bled off back to the initial pressure. With the elevated pressure bled off, the hydraulic distributor 1, still remains in its first position.

As indicated by the arrows in FIG. 7, the coefficient of the indexer spring 130 now overcomes the applied pressure such that the indexer spring 130 applies force to the flange 126 of the indexer piston 122 sufficient to force the indexer piston 122 upwards. As the indexer piston 122 moves upwards, the indexer sleeve 134 moves upward toward its uppermost position. As the indexer sleeve 134 moves upward, the tapered surface 148 of an intermediate receptacle engages the indexer pin 132. With continued upward movement, the indexer pin 132 forces the indexer sleeve 134 to rotate as it moves upward. The upward travel and rotation of the indexer sleeve 134 continues until the intermediate receptacle 146 is engaged by the indexer pin 132. At this point, the indexer sleeve 134 is prevented from returning to its uppermost position and is maintained in its intermediate position by the interaction between the indexer pin 132 and the intermediate receptacle 146. Further, the indexer sleeve 134 has rotated such that the indexer pin 132 is in axial alignment with the tapered surface 142 of an upper stop 140. With the indexer sleeve 134 in an intermediate position, the control rod 128 extends up to the bore shoulder 58.

Once again, the lock piston 88 remains in its upper position with the lock balls 108 of the fixed cage 100 engaged with the recess 69a of the shuttle sleeve 60, and the shuttle sleeve 60 is maintained in its upper position. Thus, the supply alternator 36 is maintained in its upper position in which the bled off pressure is restricted from flow into the internal conduit 26 of the upper seating element 22 but is free to flow through the internal conduit 26 of the lower seating element 22.

FIG. 8 illustrates the hydraulic distributor 1 with the pressure further bled off to a pressure lower than the initial pressure. The hydraulic distributor 1 continues to remain in its first position.

As indicated by the arrows in FIG. 8, the coefficient of the lock spring 98 is no longer overcome and lock spring 98 applies a downward force to the flange 92 such that the piston rod 90 moves downward until the flange 92 abuts and is resisted by the fixed cage 100. As the piston rod 90, and thus the control rod 94, moves downward, the lock balls 108 are once again received in the tapered detent 96 of the control rod 94 and are removed from engagement with the first recess 69a of the locking profile 68 of the shuttle sleeve 60. The shuttle sleeve 60 is no longer fixedly engaged to the fixed cage 100. However, the applied pressure maintains the shuttle sleeve 60 in its upward position.

FIG. 9 illustrates the subsequent bleeding off of the pressure applied to the hydraulic distributor 1 to a predetermined release pressure. Under the release pressure, the hydraulic distributor 1, as indicated by the arrows, moves to its second position.

As stated above with reference to FIG. 8, the shuttle sleeve 60 is no longer held in an upper position by engagement of the lock balls 108 of the fixed cage 100. Thus, once all of the pressure is bled to a predetermined release pressure, the shuttle sleeve 60 is forced to its lower position by action of the shuttle sleeve spring 64, that has a coefficient sufficiently low to be overcome by minimal pressures but able to overcome a no-pressure state. As indicated above, the downward movement of the shuttle sleeve 60 is no longer impeded by the control rod 128 of the indexer piston 122, as it is held in an intermediate position by the engagement of the indexer sleeve 134 by the indexer pin 132.

As the shuttle sleeve 60 moves into its lower position, the control screws 48, which are affixed to the shuttle sleeve 60, are forced into a lower position within the control chamber 34. Consequently, the supply alternator 36 is forced into its lower position in which the lower actuation ball 38 matingly engages the seating surface 24 of the lower seating element 22. Such engagement is secured by the force supplied by the compression of the lower ball spring 44. The upper ball 38 is maintained within the ball housing 40 by the upper retaining shoulder 42.

As has been discussed, the shuttle sleeve spring 64 has a sufficiently low coefficient that the switching of the shuttle sleeve 60 from its upper position to its lower position does not occur until nearly all of the pressure has been bled off. In essence, the action of the shuttle sleeve spring 64 acts to impart a time delay on the switching of the hydraulic distributor 1 from its first position to its second position. This time delay avoids problems associated with prematurely bleeding off the pressure as the supply alternator 36 is toggled from its upper position to its lower position. In addition to affecting the operation of the hydraulic distributor 1, premature bleeding off of the pressure affects the instantaneous delivery of power to the hydraulic devices.

FIGS. 10-13 illustrate the various stages of the hydraulic distributor 1 of the present invention as it moves from its second position to its first position. To begin, FIG. 10 provides a cross-sectional view of the hydraulic distributor 1 in its second position under an initial pressure. As discussed above, an intermediate receptacle 146 of the indexer sleeve 134 is engaged by the indexer pin 132. The indexer sleeve 134 is maintained in this position by the bias of the indexer spring 130. As discussed above, force applied to the lower thrust surface 138 is resisted by the interaction between the indexer pin 132 and the intermediate receptacle 146. In this position, the control rod 128 of the indexer piston 122 does not force the shuttle sleeve 60 away from the bore shoulder 58 and away from its lower position.

Under initial pressure, the hydraulic distributor 1 remains in its second position. Again it should be understood that for purposes of illustration, the term "initial pressure" refers to a pressure sufficient to overcome the spring coefficient of the lock spring 98, but insufficient to overcome the spring coefficient of the indexer spring 130.

Under these initial pressure conditions, the coefficient of the lock spring 98 is overcome such that the flange 92 applies a force to the lock spring 98 sufficient to compress the lock spring 98 and enable the piston rod 90 to move upward (indicated by the arrow) toward the chamber base 84 of the lock piston chamber 80. The piston rod 90 continues to compress the spring until its shoulder 87b abuts the chamber base 84 preventing further movement. In the embodiment shown in FIG. 10, to protect the surface of the chamber base 84, and to adjust the load of the lock spring 98, a spacer 121 is provided. As the piston rod 90, and thus control rod 94, moves upward, the lock balls 108 are forced out of the tapered detent 96 and into engagement with the second recess 69b of the locking profile 68 of the shuttle sleeve 60. The shuttle sleeve 60 is consequently fixedly engaged to the fixed cage 100 and prevented from upward movement.

With the shuttle sleeve 60 fixed in its lower position, the supply alternator 36 is maintained in its lower position in which the lower actuation ball 38 matingly engages the seating surface 24 of the lower seating element 22. The initial pressure is restricted from flow into the lower internal conduit 26 of the lower seating element 22 but is free to flow through the internal conduit 26 of the upper seating element 22. Thus, the initial pressure can be used to supply hydraulic fluid pressure to a hydraulic device attached to the upper seating element 22.

FIG. 11 displays a cross-sectional view of hydraulic distributor 1 as the initial pressure is increased to an elevated pressure. Under this elevated pressure, the hydraulic distributor 1 still remains in its second position. As above, it should be understood that for purposes of illustration, the term "elevated pressure" refers to a pressure sufficient to overcome the spring coefficient of the lock spring 98, and sufficient to overcome the spring coefficient of the indexer spring 130.

As indicated by the arrows in FIG. 11, the coefficient of the indexer spring 130 is overcome such that the flange 126 of the indexer piston 122 applies a force to the indexer spring 130 sufficient to compress the indexer spring 130 and enable the piston rod 124 to move downward toward the chamber base 120. The action of the piston rod 124 forces the indexer sleeve 134 downward toward its lowermost position. As the indexer sleeve 134 moves downward, the indexer pin 132 engages the tapered surface 142 of an upper stop 140 which forces the indexer sleeve 134 to rotate. The downward travel and rotation of the indexer sleeve 134 continues until an upper stop 140 is engaged by the indexer pin 132. At this point, the indexer sleeve 134 has rotated such that the indexer pin 132 is in axial alignment with the tapered surface 145 of a lower receptacle 144.

The shuttle sleeve 60 continues to be maintained in its lower position by the lock balls 108 engaging the second recess 69b of the shuttle sleeve. Thus, the supply alternator 36 is maintained in its lower position in which the elevated pressure is restricted from flow into the internal conduit 26 of the lower seating element 22 but is free to flow through the internal conduit 26 of the upper seating element 22. Thus, the elevated pressure can be used to supply hydraulic fluid pressure to a hydraulic device attached to the upper seating element 22.

FIG. 12 illustrates the hydraulic distributor 1 with the elevated pressure bled off back to the initial pressure. With the elevated pressure bled off, the hydraulic distributor 1, still remains in its second position. As indicated by the arrows in FIG. 12, the coefficient of the indexer spring 130 now overcomes the applied pressure such that the indexer spring 130 applies force to the flange 126 of the indexer piston 122 sufficient to force the indexer piston 122, and thus the indexer sleeve 134, to move upwards. As the indexer sleeve 134 moves upwards, the tapered surface 145 of a lower receptacle 144 engages the indexer pin 132. With continued upward movement, the indexer pin 132 forces the indexer sleeve 134 to rotate as it moves upward. The upward travel and rotation of the indexer sleeve 134 continues until the control rod 128 of the indexer piston 122 comes into contact with the base surface 72 of the shuttle sleeve 60. Because the shuttle sleeve 60 is locked in its lower position by the lock balls 108 of the fixed cage 100, additional upward movement of the indexer piston 122, and thus indexer sleeve 134, is prevented.

With the shuttle sleeve 60 remaining in its lower position, the supply alternator 36 is also maintained in its lower position in which the bled off pressure is restricted from flow into the internal conduit 26 of the lower seating element 22 but is free to flow through the internal conduit 26 of the upper seating element 22.

FIG. 13 illustrates the hydraulic distributor 1 with all of the pressure bled off such that the hydraulic distributor 1 returns to its first position. As indicated by the arrows in FIG. 13, the coefficient of the lock spring 98 is no longer overcome and the lock spring 98 applies a downward force to the flange 92 such that the piston rod 90 moves downward until the flange 92 abuts and is resisted by the fixed cage 100. As the piston rod 90, and thus the control rod 94, moves downward, the lock balls 108 are once again received in the tapered detent 96 of the control rod 94 and are removed from engagement with the second recess 69b of the locking profile 68 of the shuttle sleeve 60. The shuttle sleeve 60 is no longer fixedly engaged to the fixed cage 100. Now the upward movement of the indexer piston 122 is no longer resisted and the indexer sleeve 134 continues its upward movement until the indexer pin 132 is engaged by the most receptacle 144. At the same time, the control rod 128 forces the shuttle sleeve 60 into and maintains the shuttle sleeve 60 in its upper position.

As the shuttle sleeve 60 moves into its upper position, the control screws 48, which are affixed to the shuttle sleeve 60, are forced into an upper position within the control chamber 34. Consequently, the supply alternator 36 is forced into its upper position in which the upper actuation ball 38 matingly engages the seating surface 24 of the upper seating element 22. Such engagement is secured by the force supplied by the compression of the upper ball spring 44. The lower actuation ball 38 is now maintained within the ball housing 40 by the upper retaining shoulder 42.

FIG. 14 provides a sectional view of an embodiment of the present invention in which the outlet ports 20a, 20b of the hydraulic distributor 1 distribute hydraulic fluid pressure to upper and lower pistons 160a, 160b. (Again, it should be emphasized that the directional terms such as "up", "down", "upper", "lower", are used to facilitate discussion of the example and are not intended to limit the scope of the present invention.) The upper and lower pistons 160a, 160b can be used to advantage to control the actuation of various downhole well equipment and tools. In an alternate embodiment, the upper and lower pistons 160a, 160b are replaced by hydraulic control lines. It should be noted that in this embodiment, the inlet port 14 of the hydraulic distributor 1 is located in the actuator housing 52.

FIG. 15 is a diagrammatic sketch of an embodiment of the present invention wherein the hydraulic distributor 1 further comprises a ratchet assembly 210. The ratchet assembly 210 is comprised of an upper piston 226a, a lower piston 226b, and a driving rod 240. The action of the pistons 226a, 226b is used to incrementally advance or retrieve the driving rod 240 to activate or maneuver downhole tools, devices and equipment. It should be understood that the ratchet assembly 210 of the present invention can be used to manipulate and maneuver a plurality of pistons 226a, 226b and a plurality of driving rods 240.

The pistons 226a, 226b of the present invention are actuated by hydraulic fluid pressure supplied by the hydraulic distributor 1. Upper and lower piston springs 229a, 229b act to return the pistons 226a, 226b to their initial position once the pressure is bled off. Each of the pistons 226a, 226b has a control arm 228a, 228b and a pawl 230a, 230b having engagement teeth 232a, 232b attached thereto. In an embodiment of the present invention, the pawls 230a, 230b are attached to the control arms 228a, 228b by pins 236a, 236b, for example, such that the pawls 230a, 230b have some rotational flexibility, but are substantially rigid in the axial direction of the control arms 228a, 228b. Engagement springs 234a, 234b bias the pawls 230a, 230b such that the engagement teeth 232a, 232b are forced to rotate away from the control arms 228a, 228b.

It should be noted that the pawls 230a, 230b described with reference to the embodiment of the present invention illustrated in FIG. 15 are illustrative and not intended as limiting on the scope of the present invention. Any number of pawls, collet fingers, latching mechanisms, or the like, can be used to advantage to cooperate with the pistons 226a, 226b and driving rod 240 of the present invention.

A biasing surface 238a, 238b is located approximate each of the pistons 226a, 226b. Upon retraction of the pistons 226a 226b, the pawls 230a, 230b contact the biasing surface 238a, 238b which imparts a force upon the pawls 230a, 230b sufficient to overcome the bias of the engagement springs 234a, 234b and force the engagement teeth 232a, 232b to rotate toward the control arms 228a, 228b.

The driving rod 240 has a plurality of upper ratchet detents 242a and lower ratchet detents 242b with each ratchet detent 242a, 242b having a tapered release 243a, 243b. The ratchet detents 242a, 242b are oriented such that the upper detents 242a can be cooperatively engaged by the upper engagement teeth 232a on the upper pawl 230a, and likewise, such that the lower detents 242b can be cooperatively engaged by the lower engagement teeth 232b on the lower pawl 230b. The cooperative engagement enables the driving rod 240 to be incrementally advanced or retrieved. The spacing and number of ratchet detents 242a, 242b is dependent upon the application for which the present invention is being used.

In an embodiment of the present invention, the hydraulic distributor 1, and the ratchet assembly 210 are housed within an assembly frame 212 that is affixed to pipe tubing 244, for example. The assembly frame 212 has a hydraulic module 220 that houses the hydraulic distributor 1 and the upper and lower pistons 226a, 226b. The assembly frame 212 also has opposing spring modules 221 that, in combination with the hydraulic module 220, form a compression chamber 214 filled with a fluid such as oil. The control arms 228a, 228b of the pistons 226a, 226b extend therein the compression chamber 214, and the piston springs 239a, 239b are housed within the compression chamber 214. The driving rod 240 is maneuverable within the compression chamber 214 and the lower end of the driving rod 240 extends therethrough the compression chamber 214 such that the device coupling 246 located at the distal end of the driving rod 240 can be used to advantage to control downhole tools, devices, and equipment.

A compensating piston 218 is located within the assembly frame 212 that acts to maintain the fluid pressure within the compression chamber 214 equal to the external bore pressure. Maintaining equal internal and external pressure provides several advantages. One such advantage is to maintain the fluid seals 216 that act to keep the compression chamber 214 free from contaminants, such as sand, that tend to degrade the components of the ratchet assembly 210. An additional advantage of using the compensating piston 218 to maintain equal internal and external pressure is to prevent the piston effect of the rod 240. If, for example, the external bore pressure is higher than the internal pressure of the compression chamber 214, absent a high enough countering force supplied by the lower piston 226b, the driving rod 240 will be forced upwards which could act to prematurely activate or deactivate a downhole device or tool. Likewise, an internal pressure of the compression chamber 214 greater than the external bore pressure acts to force the driving rod 240 downwards. Thus, to maintain control over the maneuvering of the driving rod 240 it is necessary to maintain equal internal and external pressures.

In operation, hydraulic fluid pressure is supplied by the main control line 18 to the hydraulic distributor 1. In the sketch shown in FIG. 15, the hydraulic distributor 1 is in its second position in which hydraulic fluid flow travels through the second flow line 18b to actuate the lower piston 226b and force the pawl 238b downward. As discussed above, the engagement teeth 232b are biased away from the control arm 228b and engage a lower ratchet detent 242b of the driving rod 240. Thus, downward movement of the control arm 228b acts to force the driving rod 240 downward.

Under continued hydraulic pressure, the control arm 228b of the lower piston 226b continues to move downward until it reaches its maximum stroke. At this point, if it is desired to advance the driving rod 240 further, the pressure through the supply line 18b is bled off until the lower piston spring 233b forces the piston 226b back to its retracted position. As the piston 226b and control arm 228b are forced back toward its retracted position, the engagement teeth 232b are guided out of engagement with the lower ratchet detent 242b of the driving rod 240 by its tapered release 243b. Subsequent supply of hydraulic pressure through the supply line 18b acts to again force the lower piston 226b and pawl 238b downward. Because the engagement spring 234b keeps the engagement teeth 232b in contact with the profile of the driving rod 240, the engagement teeth 232b are forced into engagement with another ratchet detent 242b of the driving rod. The newly engaged ratchet detent 242b is displaced on the driving rod 240 above the first ratchet detent 242b at a distance approximating the stroke of the piston 226b. Under continued hydraulic pressure, the control arm 228b, and therefore driving rod 240, are forced downward until the piston 226b reaches its maximum stroke. Cycling the above sequence of events acts to maneuver the driving rod 240 through its full displacement.

While the driving rod 240 is being forced downward, there is no hydraulic fluid pressure supplied by the hydraulic distributor 1 to the upper piston 226a. As such, the upper piston spring 239a forces the upper piston 226a into its fully retracted position. As the control arm 238a is retracted by the piston 226a, the pawl 230a contacts the biasing surface 238a. Because the force supplied by the upper piston spring 239a is greater than the force supplied by the engagement spring 234b, the engagement teeth 232a are forced out of contact with the driving rod 240. Thus, the driving rod 240 can be maneuvered downward without any frictional resistance provided by the upper pawl 230a.

To reverse the process and move the driving rod 240 upwards, the hydraulic fluid pressure supplied by the main control line 18 is varied to exceed predetermined switching parameters of the hydraulic distributor 1 to switch the hydraulic distributor 1 to its second position. In its second position, the hydraulic distributor supplies hydraulic fluid pressure to the first supply line 18a. The upper piston 226a is now actuated and as it is forced upward, the engagement spring 234a forces the engagement teeth 232a of the pawl 230a into engagement with the ratchet detents 242a of the driving rod 240. As above, repeated supply and bleeding off of the hydraulic fluid pressure to the upper piston 226a acts to incrementally advance the driving rod 240 in an upward direction.

Because the driving rod 240 is advanced and retrieved by the actions of the pistons 226a, 22