EP1157191A1

EP1157191A1 - Variable stroke motor and valve

Info

Publication number: EP1157191A1
Application number: EP99909724A
Authority: EP
Inventors: Edward L. Simonds
Original assignee: Thermal Dynamics Inc
Current assignee: Thermal Dynamics Inc
Priority date: 1999-03-01
Filing date: 1999-03-01
Publication date: 2001-11-28
Also published as: CA2365827A1; BR9917187A; JP2002538362A; WO2000052305A8; WO2000052305A1; AU2886699A; MXPA01008832A; RU2217595C2; KR20020005609A; CN1344348A; CN1135293C

Abstract

A fluid valve shaft (16) is provided for a variable stroke motor (10). The valve shaft (16) has a housing (12) forming a cylinder (14), a first fluid input (18) into the cylinder (14), a first fluid output (20) out of the cylinder (14), a second fluid input (22) into the cylinder (14), and a second fluid output (24) out of the cylinder (14). Provided within the cylinder (14) is the valve shaft (16) provided with slots (26), (28), (90) and (92). As the valve shaft (16) rotates into a first position, fluid communication between the first fluid input (18) and the first fluid output (20) is shut off, while fluid communication between the second fluid input (22) and second fluid output (24) is opened. As the valve shaft (16) rotates to a second position, communication between the first fluid input (18) and first fluid output (20) is opened, while the communication between the second fluid input (22) and the second fluid output (24) is shut off. The device is preferably hooked up to a drive cylinder (48) in fluid communication with the first fluid output (20) and the second fluidinput (22). A piston (52) is provided within the drive cylinder (48). A fluid supply is operably coupled to the first fluid input (18) and means (42) are provided for rotating the valve shaft (16) at a constant speed. As pressure of the fluid increases, the stroke of the piston (52) increases, thereby generating a longer piston stroke, while the speed of the rotating valve shaft (16) remains constant.

Description

Title: VARIABLE STROKE MOTOR AND VALVE

Background of the Invention

Field of the Invention

The invention relates in general to a valve and associated piston actuated motor, and, more particularly, to a variable stroke motor and valve rotated at a constant speed.

Description of the Prior Art

In the prior art internal combustion piston-type devices, it is known to inject a liquid hydrocarbon into a piston assembly, draw the piston outward to create a vacuum strong enough to vaporize the hydrocarbon, and then compress the hydrocarbon before ignition thereof. Since the ignition of the hydrocarbon gas typically creates waste material and uses up most of the oxidizer within the piston assembly, work must be performed to remove the waste material and introduce fresh oxidizer into the piston assembly before more hydrocarbon may be combusted. One drawback associated with the internal combustion engine is the pollution generated by such an engine. Additionally, since fuels typically do not burn cleanly in an internal combustion engine waste deposits build up within the piston which can either decrease the efficiency of the engine or require regular maintenance of the engine. An additional drawback associated with internal combustion engines is the range of speeds at which typical internal combustion engines operate. Since internal combustion engines operate based upon a predetermined stroke length, the force of the combustion must be at least adequate to move the piston this predetermined stroke length. The force, however, must not be too large, otherwise components of the internal combustion engine may be damaged.

Although the "force" of the stroke may be manipulated, the length of the stroke in an internal combustion engine typically cannot be varied. Accordingly, vehicles powered by internal combustion engines typically require a clutch and gearing to step up or step down the rotational energy produced by the internal combustion engine.

The difficulties encountered in the prior art discussed hereinabove are substantially eliminated by the present invention. The present invention is designed to provide a variable stroke motor with a constant speed rotating valve to increase efficiency and decrease the drawbacks associated with prior art internal combustion engines.

Summary of the Invention

According to the invention, a fluid valve system comprising a valve housing forming a hollow cylinder; a first fluid input in fluid communication with said hollow cylinder; a first fluid output in fluid communication with said hollow cylinder; a second fluid input in fluid communication with said hollow cylinder; a second fluid output in fluid communication with said hollow cylinder; a shaft positioned within said hollow cylinder, said shaft being rotatable between a first position substantially sealing off fluid communication between said first fluid input and said first fluid output, and a second position substantially sealing off fluid communication between said second fluid input and said second fluid output; wherein said shaft is provided with a first slot and a second slot; wherein said first slot is oriented on said shaft in a manner which opens fluid communication between said first fluid input and said second fluid output when said shaft is in said second position; wherein said second slot is oriented on said shaft in a manner which opens fluid communication between said first fluid input and said first fluid output when said shaft is in said second position; and means coupled to said shaft for rotating said shaft between said first position and said second position. Brief Description of the Drawings

Fig. 1 is a side elevation in cross-section showing the valve assembly and piston assembly of the present invention; Fig. 2 is a perspective view of the valve assembly and piston assembly of

Fig. 1; and

Fig. 3 is an exploded view of the valve assembly and piston assembly of Fig. 2.

Fig. 4 is a top view in cross-section showing the valve and piston assembly of Fig. 1.

Detailed Description of the Preferred Embodiment

With reference to the drawings, a variable stroke motor is indicated generally as (10) in Fig. 1. As shown in Fig. 3, the variable stroke motor includes a valve housing (12). In the preferred embodiment, the valve housing (12) is constructed of aluminum and provided with a hollow cylinder (14) to accommodate a valve shaft (16). The valve housing (12) is constructed to form a first fluid input (18) in fluid communication with the hollow cylinder (14) and a first fluid output (20) which is also in fluid communication with the hollow cylinder (14). As shown in Fig. 1, the valve housing (12) is also formed with a second fluid input (22) and a second fluid output (24).

As shown in Fig. 3, the valve shaft (16) is provided with a first slot (26) and a second slot (28). The valve shaft (16) is also provided with a first ring seat (30), a second ring seat (32), and a third ring seat (34). Provided on the first ring seat (30), second ring seat (32), and third ring seat (34) are three Teflon rings (36), (38) and (40) which prevent the escape of fluid between the valve shaft (16) and hollow cylinder (14).

As shown in Fig. 2, secured to the valve housing (12) is a shaft rotator (42) which is operably secured to the key (44) extending from the valve shaft (16) shown in Fig. 3. The shaft rotator (42) may be a small electric motor or any similar rotation device known in the art.

As shown in Fig. 3, the first slot (26) and second slot (28) of the valve shaft (16) are disposed on opposite sides of the valve shaft (16). Accordingly, when the valve shaft (16) is positioned within the hollow cylinder (14) of the valve housing (12), as shown in Fig. 1, the second slot (28) opens fluid communication between the second fluid input (22) and the second fluid output (24). When the second slot (28) opens fluid communication between the second fluid input (22) and second fluid output (24), as shown in Fig. 1, the first slot (26) is completely covered by the valve housing (12) (Figs. 1 and 3). The portion of the valve shaft (16) on the opposite side of the first slot (26), therefore, seals off fluid communication between the first fluid input (18) and first fluid output (20).

Similarly, when the shaft rotator (42) rotates the valve shaft (16) one hundred and eighty degrees, the first slot (26) opens fluid communication between the first fluid input (18) and first fluid output (20), while the portion of the valve shaft (16) opposite the second slot (28) seals off fluid communication between the second fluid input (22) and second fluid output (28). In the preferred embodiment, the slots (26) and (28) and the inputs (18) and (22) and the outputs (20) and (24) are sized so that when the fluid communication between the first fluid input (18) and first fluid output (20) is open, fluid communication between the second fluid input (22) and second fluid output (24) is closed. Similarly, when fluid communication between the second fluid input

(22) and second fluid output (24) is open, fluid communication between the first fluid input (18) and first fluid output (20) is closed.

Secured to the valve housing (12) is a drive housing (46) which forms a drive cylinder (48) as shown in Fig. 1. In the preferred embodiment, the drive housing (46) is constructed of stainless steel seamless tubing. Preferably, the drive housing (46) is secured to a drive box (50) which, is preferably constructed of aluminum. Provided within the drive cylinder (48) is a piston (52). The piston (52) is preferably constructed with an aluminum cap (54) and an aluminum base (56). As the piston (52) is of a wobble-type, the piston (52) is provided with a plastic sealing ring (58) which allows the piston (52) to pivot two degrees from a position normal to the center axis of the drive cylinder (48), while maintaining a seal between the sealing ring (58) and the drive housing (46). A piston rod (60) preferably constructed of hardened steel is secured to the piston (52) with a securement screw (62) (Fig. 1). As shown in Fig. 3, the piston rod (60) is provided with an eyelet (62) which fits within a yoke (64) of a swing arm (66). Provided within the eyelet (62) is a needle roller bearing (68) or similar bearing known in the art to reduce friction. The needle roller bearing (68) is positioned within the eyelet (62), the eyelet (62) positioned within the yoke (64) and a dowel pin (70) constructed of heat treated steel is positioned through a first eyelet (72) of the yoke (64), the needle roller bearing (68), and a second eyelet (74) of the yoke (64). The dowel pin is preferably constructed of heat treated steel to withstand the large pressures associated with actuation of the piston rod (60). The swing arm (66) is preferably constructed of hardened steel and is provided with a large hole (76) to accommodate a pair of drive sprags (78). The drive sprags (78) are coupled to a drive shaft (80) in a manner which transfers rotational energy from the swing arm (66) to the drive shaft (80) on the drive stroke and which allows the drive shaft (80) to "freewheel" relative to the swing arm (66) on the recovery stroke so that the drive shaft (80) is not rotated in the opposite direction. As shown in Fig. 2, the drive shaft (80) extends through the drive box (50) to power a vehicle or any other drivable device.

Operably coupled in fluid communication with the first fluid input (18), is a fluid pressure generator (82) (Fig. 2). In the preferred embodiment, the pressure generator (82) is a steam generator, but the pressure generator (82) may, of course, be any similar device. The fluid pressure generator (82) is coupled to the first fluid input (18) via a transfer hose (84) (Figs. 2 and 3). In the preferred embodiment, the second fluid output (24) is also coupled to the fluid pressure generator (82) by a supplemental transfer hose (86).

As shown in Fig. 2, the variable stroke motor (10) is also provided with a supplemental valve and piston assembly (88). The supplemental valve and piston assembly (88) is substantially similar in design to the assembly described above. As shown in Fig. 3, however, the valve shaft (16) is provided with a third slot (90) and a fourth slot (92) positioned on the valve shaft (16) in reverse of the positions of the first slot (26) and second slot (28). This positioning of the slots (26), (28), (90) and (92) causes the piston (52), described above, to drive when the piston (94) of the supplemental valve and piston assembly (88) is recovering, and to recover when the piston (94) of the supplemental valve and piston assembly (88) is driving. This complimentary actuation of the pistons (52) and (94) causes the drive shaft (80) to be substantially continuously driven by one of the two pistons (52) and (94).

As shown in Fig. 4, two recovery springs (96) and (98) are provided to return the swing arm (66), described above, and the swing arm (100) of the supplemental valve and piston assembly (88) to a starting position. As each swing arm (66) and (100) alternately moves to a starting position, the swing arms (66) and (100) move their respective pistons (52) and (94) to a starting position as well. The recovery springs (96) and (98) are secured to the drive box (50) around the drive shaft (80). Each recovery spring (96) and (98) is provided with a recovery arm (102) and (104) and a securement finger (106) and (108). Once the recovery springs (96) and (98) are secured to the drive box (50), the fingers (106) and (108) are positioned within holes (110) and (112) provided in the swing arms (66) and (100). As shown in Fig. 4, the drive shaft (80), is coupled to the interior perimeters of a pair of drive sprags (114) which, in turn, are coupled on their exterior perimeters to the swing arm (100). The drive sprags (114) are oriented so that as the swing arm (100) is driven by the piston (94), the drive sprags (114) transfer the rotational motion of the swing arm (100) to the drive shaft (80). During the recovery stroke, the drive sprags (114) "freewheel" to allow the recovery spring (96) to return the swing arm (100) to its starting position without transferring a large amount of rotational energy to the drive shaft (80). An anti-backlash sprag (116) is secured to the drive shaft (80) between the swing arms (66) and (100) to further reduce the transfer of rotational energy between the swing arms (66) and (100) and the drive shaft (80). As shown in Fig. 4, the anti-backlash sprag (116) is secured to the drive box (50) within a drive shaft opening (118) provided in the drive box (50) between the swing arms (66) and (100).

The anti-backlash sprag (116) is secured to the drive box (50) by weldments or other similar securement means. The anti-backlash sprag (116) is similar in construction to the drive sprags (114), but is coupled to the drive shaft (80) in an opposite operational orientation relative to the drive sprags (114). Accordingly, when the swing arm (100) is in its drive stroke, the drive sprags (114) transfer rotational energy of the swing arm (100) to the drive shaft (80). During this drive stroke, the anti-backlash sprag (116) is in its "freewheel" orientation, allowing the drive shaft (80) to rotate freely. Once the swing arm (100) has finished its drive stroke, the recovery spring (96) returns the swing arm (100) to its starting position. As the recovery spring (96) rotates the swing arm (100), the drive sprags (114) are in their "freewheel" orientation which limits rotational energy transfer from the swing arm (100) to the drive shaft (80) and reduces the drag on the recovery spring (96).

The anti-backlash sprag (116) is provided to prevent any further rotation of the drive shaft (80) in the direction of the swing arm (100) recovery. If the friction between the drive sprags (114) and drive shaft (80) is great enough to transfer some amount of rotational energy from the drive sprags (114) to the drive shaft (80) during the recovery stroke of the swing arm (100), the anti- backlash sprag (116) prevents rotation of the drive shaft (80). Since the anti- backlash sprag (116) is welded to the drive box (50), the anti-backlash sprag (116) transfers any "backward" rotational energy of the drive shaft (80) to the drive box (50) to prevent rotation of the drive shaft (80) in the direction of the swing arm (100) recovery.

The anti-backlash sprag (116) continues to prevent backward rotation of the drive shaft (80) until one of the swing arms (66) or (100) begins rotating the drive shaft (80) on the drive stroke. In this way, the anti-backlash sprag (116), assures that the drive shaft (80) is rotated in only a single direction.

To operate the variable stroke motor (10) of the present invention, the shaft rotator (42) is actuated to rotate the valve shaft (16) within the hollow cylinder (14). The fluid pressure generator (82) is then actuated to supply a pressurized fluid, such as steam, to the first fluid input (18) and to the supplemental valve and piston assembly (88). The valve shaft (16) is thereby being rotated at a constant speed. When fluid is being applied at a low pressure to the first fluid input (18), only a small amount of fluid enters the drive cylinder (58) as the first slot (26) opens fluid communication between the first fluid input (18) and first fluid output (20). This introduction of fluid into the drive cylinder (48) forces the piston (52) away from the valve housing (12). As the swing arm (66) rotates, the eyelet (62) of the piston rod (60) pivots slightly as the swing arm (66) reciprocates. This pivoting of the piston rod (60) causes the entire piston (52) to tilt slightly relative to the drive cylinder (48). To reduce the amount of tilt, the piston (52) is arranged so that in both its starting position and its ending position the piston (52) is slightly tilted. This reduces the degree of tilt of the piston (52) when the piston is at the center of a full stroke. The swing arm (66) and piston rod (60) are preferably designed with lengths sufficient to place the piston (52) in a starting position wherein the piston (52) is tilted two degrees from normal, relative to the center axis of the drive cylinder (48).

To examine how the piston (52) tilts, it is desirable to examine a full stroke of the piston (52), that is, when fluid is being applied to the first fluid input (18) at full pressure. As the drive cylinder (48) begins to fill with fluid the piston (52) moves toward the swing arm (66) causing the piston (52) to move away from the valve housing (12), thereby pushing the swing arm (66) which begins to rotate. As the swing arm (66) rotates, the piston rod (60) pivots within the yoke (64) of the swing arm (66). The piston (52) continues to rotate until the piston (52) becomes normal to the center axis of the drive cylinder (48). This occurs when the piston (52) is one-quarter of the way through the full stroke of the piston (52).

As more fluid enters the drive cylinder (48), the piston (52) continues to pivot away from the drive shaft (80) until the piston (52) is halfway through its full stroke as shown in Fig. 1. At this point, the piston (52) is two degrees from normal relative to the axis of the drive cylinder (48), but in a direction opposite the two degree orientation of the starting point. As the drive cylinder (48) continues to fill with fluid, the swing arm (66) rotates further, until the piston (52) is three-quarters of the way through its full stroke. At this point the swing arm (66) has rotated sufficiently so that the piston (52) is again normal to the center axis of the drive cylinder (48). As the drive cylinder (48) continues to fill with fluid, the swing arm (66) continues to rotate, and the piston (52) moves toward a position two degrees from normal relative to the center axis of the drive cylinder (48). This two degree tilt is in the same direction as the two degree from normal orientation of the piston (52) at the starting point of the full stroke. At full fluid pressure, this full stroke occurs every time fluid communication is opened between the first fluid input (18) and the first fluid output (Fig.3).

Accordingly, instead of orienting the piston (52) normal to the center axis of the drive cylinder (48) in the starting position and pivoting the piston (52) through a large angle as the swing arm (66) rotates through its cycle, the piston (52) is oriented two degrees from normal to start. In this way the piston (52) starts at a position two degrees from normal, cycles through a normal position, a position two degrees from normal in the opposite direction, another normal position, and finally a position two degrees from normal in the same direction as the starting position. The total amount of deviation from the normal position is thereby kept to a minimum throughout the full stroke.

Although the variable stroke motor (10) is fully capable of cycling through the full stroke noted above, this full stroke is only realized under full fluid pressure. When only a small amount of pressure is being applied to the first fluid input (18), the piston (52) moves through a much shorter stroke cycle. As the pressure of the fluid supplied by the fluid pressure generator (82) increases, a larger amount of fluid passes from the first fluid input (18), through the first fluid output (20) and into the drive cylinder (48) with each rotation of the valve shaft (16). This larger amount of fluid entering the drive cylinder (48) moves the piston (52) more quickly, thereby generating a longer and longer stroke. The swing arm (66) translates this longer stroke into a greater rotation of the drive shaft (80). Since the shaft rotator (42) rotates the valve shaft (16) at a constant speed, each cycle takes the same amount of time, regardless of the pressure of the fluid being applied. Accordingly, a greater rotation of the drive shaft (80) in the same amount of time translates into a greater speed of the drive shaft (80). For each rotation of the valve shaft (16), the second slot (28) provided on the valve shaft (16) opens fluid communication between the second fluid input (22) and second fluid output (24) one time (Fig. 1). During this period of time, the force of the recovery spring (96) causes the swing arm (66) to push the piston rod (60) into the piston (52), thereby pushing fluid out of the drive cylinder (48) through the second fluid input (22) and second fluid out (24). The fluid is thereafter returned to the fluid pressure generator (82) through the supplemental transfer hose (86), so that the fluid can again be pressurized and recirculated through the motor (10) (Fig. 2). As the piston (52) is being driven, the supplemental valve and piston assembly (88) is working in a reciprocating manner, to drive the drive shaft (80) when the piston (52) is in its recovery stroke. As noted above, the anti-backlash sprag (116) prevents the swing arms (66) and (98) from transferring rotational energy to the drive shaft (80) during their recovery stroke.

Since the valve shaft (16) is rotated at a constant speed, varying the amount of fluid pressure entering the first fluid input (18) causes the piston (52) to stroke a longer distance, and thereby drive the drive shaft (80) a greater distance during the same interval. The fluid pressure generator (82) may be provided with a heating adjustment control (120), such as a propane valve, to vary the amount of heat delivered to the fluid pressure generator (82) and, thereby, the pressure of the fluid. Accordingly, the variable stroke motor (10) can directly convert a larger amount of heat energy into a faster rotation of the drive shaft (80).

The foregoing description and drawings merely explain and illustrate the invention, and the invention is not limited thereto, except insofar as the claims are so limited, as those skilled in the art who have the disclosure before them will be able to make modifications and variations therein without departing from the scope of the invention. For example, it is anticipated that any number of supplemental valve and piston assemblies may be coupled to the drive shaft (80), and that a wide variety of dimensions are available for the fluid inputs and fluid outputs of the valve housing and for the slots in the valve shaft.

Claims

WHAT IS CLAIMED IS:

1. A fluid valve system comprising:

(a) a valve housing forming: (i) a hollow cylinder; (ii) a first fluid input in fluid communication with said hollow cylinder; (iii) a first fluid output in fluid communication with said hollow cylinder; (iv) a second fluid input in fluid communication with said hollow cylinder;

(v) a second fluid output in fluid communication with said hollow cylinder;

(b) a shaft positioned within said hollow cylinder, said shaft being rotatable between a first position substantially sealing off fluid s communication between said first fluid input and said first fluid output, and a second position substantially sealing off fluid communication between said second fluid input and said second fluid output;

(c) wherein said shaft is provided with a first slot and a second slot; o (d) wherein said first slot is oriented on said shaft in a manner which opens fluid communication between said first fluid input and said second fluid output when said shaft is in said second position;

(e) wherein said second slot is oriented on said shaft in a manner which opens fluid communication between said first fluid input and 5 said first fluid output when said shaft is in said second position; and

(f) means coupled to said shaft for rotating said shaft between said first position and said second position.

0 2. The fluid valve system of claim 1, further comprising means for supplying fluid to said first fluid input.

3. The fluid valve system of claim 2, further comprising means for varying a pressure at which said fluid is supplied to said first fluid input.

4. The fluid valve system of claim 1, further comprising a drive housing which forms a drive cylinder in fluid communication with said first fluid output and said second fluid input.

5. The fluid valve system of claim 4, further comprising a piston located within said drive cylinder.

6. The fluid valve system of claim 5, further comprising means provided on said piston for maintaining a substantially fluid tight seal between said piston and said drive housing as said piston is rotated at least two degrees from a position normal to an axis running through said drive cylinder.

7. The fluid valve system of claim 6, wherein said piston comprises a piston cap secured to a piston rod, further comprising:

(a) a swing arm pivotally secured to said piston rod;

(b) a drive shaft; and (c) a sprag operably secured between said swing arm and said drive shaft.

8. The fluid valve system of claim 7, further comprising a backlash sprag operably secured to said drive shaft.

9. The fluid valve system of claim 8, further comprising means for biasing said piston to push fluid out of said drive cylinder.

10. The fluid valve system of claim 9, wherein said biasing means is a spring.

11. The fluid valve system of claim 1, further comprising: (a) a supplemental valve housing forming: (i) a supplemental hollow cylinder;

(ii) a first supplemental fluid input in fluid communication with said supplemental hollow cylinder; (iii) a first supplemental fluid output in fluid communication with said supplemental hollow cylinder;

(iv) a second supplemental fluid input in fluid communication with said supplemental hollow cylinder; (v) a second supplemental fluid output in fluid communication with said supplemental hollow cylinder; (b) wherein said shaft is positioned within said supplemental hollow cylinder; (c) wherein said first position of said shaft substantially seals off fluid communication between said second supplemental fluid input and said second supplemental fluid output; (d) wherein said second position of said shaft substantially seals off fluid communication between said first supplemental fluid input and said first supplemental fluid output;

(e) wherein said shaft is provided with a third slot and a fourth slot;

(f) wherein said third slot is oriented on said shaft in a manner which opens fluid communication between said first supplemental fluid input and said first supplemental fluid output when said shaft is in said first position; and

(g) wherein said fourth slot is oriented on said shaft in a manner which opens fluid communication between said second supplemental input and said second supplemental output when said shaft is in said second position.

12. The fluid valve system of claim 11, further comprising means for supplying fluid to said first fluid input and said first supplemental fluid input.

13. The fluid valve system of claim 12, further comprising means for varying a pressure at which said fluid is supplied to said first fluid input and said first supplemental fluid input.

14. The fluid valve system of claim 11, further comprising:

(a) a drive housing forming a drive cylinder in fluid communication with said first fluid output and said second fluid input; and

(b) a supplemental drive housing forming a supplemental drive cylinder in fluid communication with said first supplemental fluid output and said second supplemental fluid input.

15. The fluid valve system of claim 14, further comprising:

(a) a piston located within said drive cylinder; and

(b) a supplemental piston located within said supplemental drive cylinder.

16. The fluid valve system of claim 15, further comprising:

(a) means provided on said piston for maintaining a substantially fluid tight seal between said piston and said drive housing as said piston is rotated at least two degrees from a position normal to an axis of said drive cylinder; and (b) supplemental means provided on said supplemental piston for maintaining a substantially fluid tight seal between said supplemental piston and said supplemental drive housing as said supplemental piston is rotated at least two degrees from a position normal to an axis of said supplemental drive cylinder.

17. The fluid valve system of claim 16, wherein said piston comprises a piston cap secured to a piston rod, wherein said supplemental piston comprises a supplemental piston cap secured to a supplemental piston rod, further comprising: (a) a swing arm pivotally secured to said piston rod;

(b) a supplemental swing arm pivotally secured to said supplemental piston rod; (c) a drive shaft;

(d) a sprag secured between said swing arm and said drive shaft; and

(e) a supplemental sprag secured between said supplemental swing arm and said drive shaft.

18. The fluid valve system of claim 17, further comprising a backlash sprag secured to said drive shaft.

19. The fluid valve system of claim 18, further comprising: (a) means for biasing said piston to force fluid out of said drive housing; and (b) supplemental means for biasing said supplemental piston to force fluid out of said supplemental drive cylinder.

20. The fluid valve system of claim 19, wherein said biasing means is a spring and wherein said supplemental biasing means is a supplemental spring.

AMENDED CLAIMS

[received by the International Bureau on 2 December 2000 (02.12.00) ; original claims 1 -20 replaced by amended claims 1 -17 (5 pages ) ]

1. A fluid valve system comprising:

(a) a valve housing forming: (i) a hollow cylinder;

(ii) a first fluid input in fluid communication with said hollow cylinder; (iii) a first fluid output in fluid communication with said hollow cylinder; (iv) a second fluid input in fluid communication with said hollow cylinder; (v) a second fluid output in fluid communication with said hollow cylinder;

(b) a valve shaft positioned within said hollow cylinder, said valve shaft being rotatable between a first position substantially sealing off fluid communication between said first fluid input and said first fluid output, and a second position substantially sealing off fluid communication between said second fluid input and said second fluid output; (c) wherein said valve shaft is provided with a first slot and a second slot;

(d) wherein said first slot is oriented on said valve shaft in a manner which opens fluid communication between said first fluid input and said second fluid output when said valve shaft is in said second position;

(e) wherein said second slot is oriented on said valve shaft in a manner which opens fluid communication between said first fluid input and said first fluid output when said valve shaft is in said second position; and (f) means coupled to said valve shaft for rotating said valve shaft between said first position and said second position. (g) a drive housing which forms a drive cylinder in fluid communication with said first fluid output and said second fluid input;

(h) a piston cap located within said drive cylinder; (i) a piston rod secured to said piston cap;

(j) a swing arm pivotally secured to said piston rod;

(k) a drive shaft;

(1) a sprag operably secured between said swing arm and said drive shaft; and o (m) means for reciprocating said piston rod at a first stroke length and for reciprocating said piston rod at a second stroke length wherein said first stroke length is greater than said second stroke length.

5 2. The fluid valve system of claim 1, wherein said means for reciprocating said piston rod at said first and second lengths further comprises means for supplying fluid to said first fluid input.

3. The fluid valve system of claim 2, further comprising means for varying a o pressure at which said fluid is supplied to said first fluid input.

4. The fluid valve system of claim 1, further comprising means provided on said piston cap for maintaining a substantially fluid tight seal between said piston cap and said drive housing as said piston cap is rotated at least two 5 degrees from a position normal to an axis running through said drive cylinder.

5. The fluid valve system of claim 1, further comprising a backlash sprag operably secured to said drive shaft.

0 6. The fluid valve system of claim 5, further comprising means for biasing said piston to push fluid out of said drive cylinder.

7. The fluid valve system of claim 6, wherein said biasing means is a spring.

8. The fluid valve system of claim 1, further comprising:

(a) a supplemental valve housing forming: (i) a supplemental hollow cylinder;

(ii) a first supplemental fluid input in fluid communication with said supplemental hollow cylinder; (iii) a first supplemental fluid output in fluid communication with said supplemental hollow cylinder; 0 (iv) a second supplemental fluid input in fluid communication with said supplemental hollow cylinder; (v) a second supplemental fluid output in fluid communication with said supplemental hollow cylinder;

(b) wherein said valve shaft is positioned within said supplemental s hollow cylinder;

(c) wherein said first position of said valve shaft substantially seals off fluid communication between said second supplemental fluid input and said second supplemental fluid output;

(d) wherein said second position of said valve shaft substantially seals o off fluid communication between said first supplemental fluid input and said first supplemental fluid output;

(e) wherein said valve shaft is provided with a third slot and a fourth slot;

(f) wherein said third slot is oriented on said valve shaft in a manner 5 which opens fluid communication between said first supplemental fluid input and said first supplemental fluid output when said valve shaft is in said first position; and

(g) wherein said fourth slot is oriented on said valve shaft in a manner which opens fluid communication between said second 0 supplemental input and said second supplemental output when said valve shaft is in said second position.

9. The fluid valve system of claim 8, further comprising means for supplying fluid to said first fluid input and said first supplemental fluid input.

10. The fluid valve system of claim 9, further comprising means for varying a pressure at which said fluid is supplied to said first fluid input and said first supplemental fluid input.

11. The fluid valve system of claim 8, further comprising:

12. The fluid valve system of claim 11, further comprising:

(a) a piston located within said drive cylinder; and

(b) a supplemental piston located within said supplemental drive cylinder.

13. The fluid valve system of claim 12, further comprising:

14. The fluid valve system of claim 13, wherein said piston comprises a piston cap secured to a piston rod, wherein said supplemental piston comprises a supplemental piston cap secured to a supplemental piston rod, further comprising:

(a) a swing arm pivotally secured to said piston rod;

(b) a supplemental swing arm pivotally secured to said supplemental piston rod;

(c) a drive shaft;

(d) a sprag secured between said swing arm and said drive shaft; and

(e) a sprag secured between said supplemental swing arm and said drive shaft.

15. The fluid valve system of claim 14, further comprising a backlash sprag secured to said drive shaft.

16. The fluid valve system of claim 15, further comprising: (a) means for biasing said piston to force fluid out of said drive housing; and (b) supplemental means for biasing said supplemental piston to force fluid out of said supplemental drive cylinder.

17. The fluid valve system of claim 16, wherein said biasing means is a spring and wherein said supplemental biasing means is a supplemental spring.