US2270743A - Pressure fluid motor - Google Patents

Description

Jan. 20, 19.42. s c 2,270,743

PRESSURE FLUID MOTOR I Filed July 16, 1940 2 Sheets-Sheet l 4/ /2 3 5 lhveniar: fiani cyt nekzir.

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Jan. 20, 1942. s c R 7 2,270,743

PRESSURE FLUID MOTOR Filed July 16, 1940 2 Sheets-Sheet 2 In ven for; 6 fi arzZjEc in/czair;

dit y Patented Jan. 20, 1942 UNITED PRESSURE FLUID MOTOR Frank E. Sinclair, Claremont, N. H., assignor to Sullivan Machinery Company, a corporation of Massachusetts Application July 16, 1940, Serial No. 345,793

19 Claims.

This invention relates to pressure fluid motors, and more particularly to improvements in a pressure fluid motor of the reciprocating piston, impact type especially designed for use in impact tools such as hammer rock drills.

An object of this invention is to provide an improved pressure fluid motor. Another object is to provide an improved pressure fluid motor having improved fluid distribution means. A further object is to provide an improved fluid distribution means embodying improved fluid distributing valve mechanism whereby the flow of pressure fluid to the motor is efiectively controlled. Another object is to provide an improved valve mechanism of the multi-valve type. A still further object is to provide an improved fluid distributing valve mechanism embodying a pair of cooperating, relatively movable, fluid distributing valves of an improved design. Yet another object is to provide an improved valve throwing means for effectively and positively throwing the distributing valves into their different operating positions. These and other objects of the invention will, however, hereinafter more fully appear in the course of the following description.

In the accompanying drawings there are shown for purposes of illustration two forms which the invention may assume in practice.

In these drawings:

Fig. 1 is a central longitudinal sectional view taken through a pressure fluid motor constructed in accordance with an illustrative embodiment of the invention.

Figs. 2 and 3 are views similar to Fig. 1, showing the moving motor parts in difierent operating positions.

Fig. 4 is an enlarged fragmentary view taken on the plane of Fig. 3, illustrating details of the valve mechanism.

Fig. 5 is a cross sectional view taken on line 5-5 of Fig. 1.

Fig. 6 is a detail sectional View showing the fluid supply passage means of the valve mechamsm.

Fig. 7 is a front elevational view of the front valve.

Fig. 8 is a front elevational view of the rear valve.

Fig. 9 is a sectional View similar to Fig. 1, taken through a pressure fluid motor constructed in accordance with another illustrative embodiment of the invention.

In both illustrative embodiments of the invention the improved pressure fluid motor is of the percussive type especially designed for use in hammer rock drills, although it will be evident that the improved pressure fluid motor may be used in impact tools of various other types.

In the illustrative embodiment of the invention shown in Figs. 1 to 8, inclusive, the improved pressure fluid motor is generally designated l and comprises a motor cylinder 2 having a bore 3 containing a reciprocatory hammer piston 4. The hammer piston has a piston head 5 slidingly fitting the bore 3 of the motor cylinder and a striking bar 6 adapted to deliver impact blows to the shank of a usual rock drill steel. The motor cylinder has a front head 1 closing the front end of the cylinder bore, and this head has a bore for slidingly receiving the piston striking bar, The motor cylinder has a rear head 8 closing the rear end of the cylinder bore, and this head is circular in shape to fit an enlarged bore 9 arranged in axial alinement with the cylinder bore. Also received in the bore 9 are a ratchet ring I0 and elements H, l2 and [3 which cooperate with the rear head 8 to provide a valve chest, and a member 14 also fits the bore 9 and engages the ratchet ring I 0 for holding the latter and the elements I I, I2 and I3 in assembled position against the rear cylinder head 8. A usual dowel pin I5 is seated in grooves in the wall of the bore 9 and engages alined grooves in the elements 8, I0, I I, I2 and I3 for holding the latter against rotative movement with respect to the cylinder. The member I4 and the front cylinder head are secured to the cylinder in any suitable manner.

As is usual in hammer rock drills, there is provided a conventional form of drill steel rotation means operated by the motor piston for intermittently rotating the drill steel as the latter is percussively actuated. This drill steel rotation means comprises a rotatable pawl carrier l6 carrying usual spring-pressed pawls engaging the teeth I! of the ratchet ring l0, and this pawl carrier is integral with a spirally grooved rifle bar l8 slidingly interlocked with the spiral vanes of a rifle nut I9 secured within the hammer piston. During the return piston movement the pawls of the pawl carrier engage the ratchet teeth to hold the rifle bar against rotation, and the rifle nut engaging the spiral grooves on the rifle bar effects rotation of the hammer piston, and the rotary piston movement is transmitted, through straight grooves 20 on the piston striking bar 6 which slidingly engage the straight lugs of a usual chuck nut (not shown), to the drill steel chuck, all in a manner well understood by those skilled in the art. The element I of the valve chest has an integral sleeve portion 2| which extends forwardly axially of the motor cylinder and is tightly fitted at its forward end within an axial bore 22 in the rear cylinder head 8. The rifle bar I8 extends forwardly through the bore of the sleeve portion 2| in the manner shown.

Now referring to the improved fluid distribution means and more particularly to the improved valve mechanism, it will be noted that formed in the valve chest provided by the elements 8, II, I2 and I3 is a valve chamber 23, and the element [3 has a bore 24 providing the outer wall of the valve chamber while the exterior surface of the sleeve portion 2| provides the inner valve chamber wall. The inwardly facing surfaces of the elements 8 and I2 provide the end walls of the valve chamber, and these elements have annular portions 25 and 26 projecting inwardly within the valve chamber, and these annular portions have annular grooves 21 and 28 respectively. Annular fluid supply spaces 29 and 39 communicate with the valve chamber through restricted annular clearance spaces 3| and 32 surrounding the annular portions 25 and 26 respectively. Arranged in the valve chamber 23 is a pair of identical valves 33 and 34, these valves being of the sleeve type having sleevelike body portions 35 slidingly guided on the exterior of the sleeve portion 2| and slidingly fitting the inner surfaces 36 of the annular portions 25 and 26. The sleevelike body portions of the valves have at their adjacent ends external annular flanges 31 slidingly fitting at their exterior peripheries the bore 24 of the element l3. The sleevelike bodies of the valves are movable into end abutting engagement, and the inner faces of the external valve flanges have near their peripheries annular flanges 38 also movable into end abutting engagement. The outer annular flanges 38 are preferably notched at 39 to permit free access of pressure fluid to the adjacent faces of the valves. Fluid distribution passages 49 connect the groove 21 with the rear end of the cylinder bore, while fluid distribution passages 4| connect the groove 28 with the front end of the cylinder bore. A series of longitudinal passages 42 in-the element I3 connect the fluid supply spaces 29 and 39. A radial passage 43 in the element I3 connects the space between the valves with a throwing passage 44 communicable through ports 45 and 46 with the cylinder bore at longitudinally spaced points. The annular spaces 41 and 48, within which the outer end portions of the sleevelike bodies of the valves are arranged, have passages 49 and 59 opening into them, the passages 49 and 59 respectively formed in the elements 8 and I2 and communicating with passages and 52 connected by ports 53 and 54 respectively with the cylinder bore at longitudinally spaced points. Pressure fluid may be supplied to the valve chest from any suitable source of supply under the control of a usual throttle valve, so that when the valve is in open position pressure fluid may flow to a chamber55 in the member I4 and pass through ports 56 to an annular recess 51, as shown most clearly in Fig. 6. This recess is connected by the spaces between the ratchet teeth of the ratchet ring with a recess 58 in turn connected by passages 59 and 69 in the elements II and I2 respectively with the annular fluid supply space 39. Pressure fluid flows from this fluid supply space 39 through the passages 42 to the annular fluid supply space 29. Restricted passages 6| which have a combined flow area greater than that of the passage 43, connect certain of the passages 42 with the space between the valves, thereby to provide a continuous leakage of pressure fluid to this space. A restricted leak passage 62 connects the fluid supply space 29 with the passage 49 communicating with the annular space 41 at the forward end of the front valve sleeve, while a similar leak passage 63 connects the supply recess 58 with the passage 59 communicating with the annular space 48 at the rear side of the Formed in the walls of sleeve of the rear valve. the cylinder bore is an annular exhaust groove 64 arranged substantially midway between the ports 45 and 46 of the throwing passage 44, and between the ports 53 and 54. A free exhaust passage 65 connects the groove directly to atmosphere.

The mode of operation of this embodiment of the invention will be clearly apparent from the description given. When the throttle valve is turned into its open position, pressure fluid may flow from the chamber 55 through passages 56, annular recess 51, the spaces between the ratchet teeth I! of the ratchet ring I9, annular recess 58 and passages 59 and 69 to the fluid supply space 39 and thence through passages 42 to the fluid supply space 29. When the fluid'distributing valves 33 and 34 are in the position shown in Fig. 1, pressure fluid leaking through the leak passage 63 builds up to a substantial pressure in the annular space 48 at the rear end of the rear valve sleeve, thereby positively holding the rear valve in open position, and the rear valve, due to its abutting engagement with the front valve, maintains the latter in its foremost closed position. With the distributing valves thus disposed, pressure fluid may flow from the rear supply space 39 through the restricted clearance space 32, through the valve chamber past the rear face of the rear valve 34 and through the distribution passages 4| to the front end of the cylinder bore. Concurrently, the communication of the front supply space 29 with the distribution passages 49 is cut off by the front valve 33, and the rear end of the cylinder bore and the annular groove 21 are connected to exhaust through the exhaust groove 64 and exhaust passage 65. Pressure fluid flowing to the front end of the cylinder bore acts on the front pressure area of the piston head of the hammer piston to move the latter rearwardly to effect its return stroke. As the motor piston moves rearwardly, the leading edge of the piston head first overruns the exhaust groove 64 and thereafter the following edge of the piston head uncovers the port 46, thereby admitting pressure fluid from the cylinder bore through port 46, throwing passage 44 and passage 43 to the space between the valves 33 and 34, the pressure fluid acting on the effective front pressure area of the rear valve 34 to throw the latter rearwardly from the position shown in Fig. 1 to its closed position shown in Fig. 2. When the distributing valves are in their closed positions shown in Fig. 2, supply of pressure fluid to the cylinder bore is momentarily completely out off, and as the motor piston continues to move rearwardly by expansion of the fluid and momentum, the leading edge of the piston head overruns the ports 45 and 53 and the following edge of the piston head uncovers the port 54, thereby causing the pressure in the annular space 48 at the rear end of the rear valve sleeve to be substantially reduced until it equals the pressure of the expanded fluid in the front end of the cylinder bore. Upon continued rearward piston movement, the following edge of the piston head uncovers the exhaust groove 64, connecting the forward end of the cylinder bore, the space between the valves and the annular space 48 at the rear end of the rear valve sleeve, to exhaust. When the piston head covers the port 53, pressure fluid flowing through the leak passage 62 builds up a pressure in the annular space 41 at the forward end of the front valve sleeve, and as the piston continues to move rearwardly a compression pressure is built up in the rear end of the cylinder bore, and this compression pressure acts through the passages 40 on the front pressure area of the external valve flange of the front valve 33 to throw the latter rearwardly from its position shown in Fig. 2 to its open position shown in Fig. 3, at least upon venting of pressure to exhaust through passages 43, 44, and 46, when the front end of the piston uncovers the exhaust groove 64. The fluid which has built up to a substantial pressure in the annular space 41 acts on the front pressure area of the front valve sleeve and supplements the pressure acting on the front face of the external valve flange in the throwing of the valve, and when the valve is thrown this pressure positively holds the front valve in its rearmost position. The front valve, due to its abutting engagement with the rear valve, maintains the latter in its rearmost closed position. When the valves are in the position shown in Fig. 3, pressure fluid may flow from the annular supply space 29 through the restricted clearance space 3|, through the valve chamber past the forward face of the front valve 33 and through the annular groove 21 and distribution passages 40 to the rear end of the cylinder bore, the pressure fluid acting on the rear pressure area of the piston head to move the motor piston forwardly to effect its working stroke. As the motor piston continues to move forwardly, the leading edge of the piston head covers the exhaust groove 64 and thereafter covers the port 54. When the port 54 is covered, pressure fluid flowing through the leak passage 63 and through the passage 50 to the annular space 48 at the rear side of the rear valve sleeve begins to build up a pressure fairly rapidly. Upon continued forward piston movement, the following edge of the piston head uncovers the port 45, admitting pressure fluid from the rear end of the cylinder bore through the throwing passage 44 and the passage 43 to the space between the valves to act on the rear pressure area of the external valve flange to throw the front valve forwardly from the position shown in Fig. 3 to the position shown in Fig. 2. When the port 53 is uncovered by the following edge of the piston head. the pressure in the annular space 41 at the forward side of the front valve sleeve is, it will be observed substantially reduced to a pressure canal to the reduced pressure in the rear end of the cylinder bore. As the piston continues to move forwardly, the leadin edge of the piston head covers the port 46 and thereafter the following edge of the piston head uncovers the exhaust groove 64, connecting the rear end of the cylinder bore, the space between the valves and the annular space 41 at the front side of the front valve sleeve, to exhaust. The piston continues to move forwardly by momentum, and as it moves forwardly a compression pressure is built up within the front end of the cylinder bore and this compression pressure acts through the distribution passages 4| on the rear pressure area of the external flange of the rear valve to throw the rear valve forwardly from its position shown in Fig. 2 to its open position shown in Fig. 1. The fluid leaking through the passage 63 builds up to a substantial pressure in the annular space 48 at the rear side of the rear valve sleeve and supplements the pressure fluid acting on the rear pressure area of the external valve sleeve in the throwing of the valve, and when the valve is thrown this supplemental pressure positively holds the valve in its thrown position. Pressure fluid is then again admitted to the front end of the cylinder bore and the operations above described are rapidly repeated during normal operation of the motor.

In the embodiment of the invention shown in Fig. 9, the structure of the pressure fluid motor is similar to that above described with the exception that the passages 5| and 52 are omitted and the passage 44 has its ports 45 and 46 communieating with the cylinder bore at different points with respect to the exhaust groove 64. In this construction, the annular spaces 41' and 48' at the remote ends of the sleeve-like bodies of the valves 33 and 34 are connected through passages 49' and 5|) with restricted leak passages 5| and 52 which in turn communicate with the fluid supply. The passage 44' communicates with the cylinder bore through ports 45' and 46' located in adjacency to the exhaust groove 64 respectively at the opposite sides of th latter. The pressure fluid leaking through the passages 5| and 52' acts on the remote ends of the sleeve-like bodies of the valves, and since the pressure areas on the ends of the valve bodies are equal these areas are substantially balanced. Due to the restricted clearance spaces 3| and 32, the pressure in the grooves 21, 28 at the side of the valve which is in a position to supply fluid to an end of the cylinder bore, is substantially reduced due to rapid flow, so that when pressure builds up in the space between the valves, the open valve is thrown I into its closed position to cut off such flow.

.The mode of operation of this form of the invention is as follows. When the parts are in the position shown in Fig. 9, pressure fluid may flow from the supply space 30, through the restricted clearance space 32, through the valve chamber past the rear face of the rear valve 34 and through the annular groove 28 and distribution passages .4! to the front end of the cylinder bore. Concurrently, the rear end of the cylinder bore and the groove 21 at the forward side of the front valve flange are connected to exhaust through the exhaust groove 64. Pressure fluid flowing to the front end of the cylinder bore acts on the front pressure area of the piston head to move the piston rearwardly to effect its return stroke. As the motor piston moves rearwardly, the leading edge of th piston head first overruns the exhaust groove 64, and thereafter the leading edge of the piston head overruns the port 45 to cut on communication of the passage 44 with the cylinder bore. The fluid flowing through the passages 3| to the space between the valves will then build up on the front face of the rear valve 34, and since this pressure is substantially greater than the opposing pressure due to the flow of fluid from the groove 28 to the front end of the cylinder bore) the rear valve will be thrown rearwardly and effect cut off for the front end of the cylinder. The valves are at that time both closed, thereby cutting off momentarily flow of fluid to both ends of the cylinder bore. As the piston continues to move rearwardly, the following edge of the piston head uncovers the port 46', enabling the pressure fluid in the space between the valves to be displaced when the forward valve is opened, as will later be described. Upon continued rearward piston movement, the fluid trapped in the rear end of the cylinder bore is compressed. This compression pressure acts on the front area of the front valve flange 31 to throw the front valve 33 rearwardly into its rearmost position in abutting engagement with the rear valve 34. The following edge of the piston head, as the piston moves rearwardly to complete its rearward stroke, uncovers the exhaust groove 64, thereby to connect the front end of the cylinder bore to exhaust. When the valves 33 and 34 are in their rearward positions, pressure fluid may flow from the supply space 29, through th restricted clearance space 3|, through the valve chamber past the forward face of the front valve and through groove 27 and passages 40 to the rear end of the cylinder bore. Pressure fluid acting on the rear pressure area of the piston head of the piston moves the latter forwardly to effect its working stroke. As the piston moves forwardly, the leading edge of the piston head first covers the port 45' and thereafter covers the exhaust groove 64 and the port 46. Thereupon, the fluid flowing through the passages 6| to the space between the valves will build up on the rear face of the front valve 33, and this pressure will overcome the reduced opposing pressure (which will be reduced due to the flow of fluid in the groove 21 to the rear end of the cylinder bore) to throw the front valve forwardly. At that time both valves are closed, thereby cutting off momentarily flow of fluid to both ends of the cylinder bore. Upon continued forward piston movement, the port 45' is uncovered by the following edge of the piston head, thereby somewhat reducing the pressure in the space between the valves in readiness for forward movement of the rear valve, but not enough to allow the forward valve to move rearwardly. As the piston continues to move forwardly, the fluid in the front end of the cylinder bore is compressed and this compression pressur acts on the rear pressure area of the rear valve flange 31 to throw the rear valve 34 forwardly into its initial position in abutting engagement with the front valve 33. The operations above described are rapidly repeated during normal operation of the motor.

As a result of this invention, it will be noted that an improved pressure fluid motor is provided A having improved fluid distribution means of an extremely efficient design. It will further be evident that by the provision of separate, relatively movable, fluid distributing valves, together with the improved throwing means for the valves, the motor is not only extremely efficient but is also more rapid and powerful in operation. Other uses and advantages of the improved pressure fluid motor will be clearly apparent to those skilled in the art.

While there are in this application specifically described two forms which the invention may assume in practice, it will be understood that these forms of the same are shown for purposes of illustration and that the invention may be modified and embodied in various other forms without departing from its spirit or the scope of the appended claims.

What I claim as new and desire to secure by Letters Patents is:

1. In a pressure fluid motor, a cylinder having a bore, a piston reciprocable in said bore, and fluid distribution means for supplying pressure fluid to the cylinder bore to effect reciprocation of said piston including means providing a valve chamber, relatively movable fluid distributing valves arranged in said valve chamber, a pressure fluid supply, said valves respectively controlling the flow of fluid from said supply to the opposite ends of the cylinder bore, said valves having pairs of opposed pressure areas, and means for shifting said valves into their different operating positions including means for subjecting simultaneously one of said pairs of opposed pressure areas to piston-controlled cylinder pressure and means for subjecting the other pair of said opposed pressure areas in alternation to piston-controlled reduced pressure.

2. In a pressure fluid motor, a cylinder having a bore, a piston reciprocable in said bore, and fluid distribution means for supplying pressure fluid to the cylinder bore to effect reciprocation of said piston including means providing a valve chamber, relatively movable fluid distributing valves arranged in said valve chamber, a pressure fluid supply, said valves respectively controlling the flow of fluid from said supply to the opposite ends of the cylinder bore, said valves having pairs of opposed pressure areas, and means for shifting said valves into their different operating positions including means for subjecting simultaneously one of said pairs of opposed pressure areas to piston-controlled cylinder pressure, means for subjecting the other pair of said opposed pressure areas in alternation to piston-controlled reduced pressure and passage means for providing a continuous restricted flow of pressure fluid to said last mentioned pair of opposed pressure areas.

3. In a pressure fluid motor, a cylinder having a bore, a piston reciprocable in said bore, and fluid distribution means for supplying pressure fluid to said cylinder bore to effect reciprocation of said piston including means providing a valve chamber, a pair of relatively reciprocable fluid distributing valves movable into abutting relation and respectively controlling the flow of pressure fluid to the opposite ends of the cylinder bore, said valves cooperating to provide a space therebetween, and means for shifting said valves into their different operating positions including means for supplying a restricted flow of pressure fluid to the space between the valves, means under piston control for effecting a reduction in the pressure in the space between the valves and means for continuously connecting opposed pressure areas on the valves to line pressure.

4. In a pressure fluid motor, a cylinder having a bore, a piston reciprocable in said bore, and fluid distribution means for supplying pressure fluid to said cylinder bore to effect reciprocation of said piston including means providing a valve chamber, a pair of relatively reciprocable fluid distributing valves movable into abutting relation and respectively controlling the flow of pressure fluid to the opposite ends of the cylinder bore, said valves cooperating to provide a space therebetween, and means for shifting said valves into their different operating positions including means for supplying a restricted flow of pressure fluid to the space between the valves, means under piston control for effecting a reduction in the pressure in the space between the valves, means for continuously connecting opposed pressure areas on the valves to line pressure and means for subjecting other opposed pressure areas on the valves to the pressures within the opposite ends of said cylinder.

5. In a pressure fluid motor, a cylinder having a bore, a piston reciprocable in said bore, and fluid distribution means for supplying pressure fluid to said cylinder bore to effect reciprocation of said piston including means providing a valve chamber, relatively reciprocable valves mounted in said valve chamber and movable intoabutting relation, said valves having sleevelike bodies and enlarged external flanges and cooperating to provide a space therebetween, passage means controlled by said valves respectively for supplying pressure fluid to the opposite ends of the cylinder bore, and means for shifting said valves into their diiferent operating positions including means for connecting opposed pressure areas at the remote ends of the sleevelike valve bodies continuously to line pressure, means for supplying pressure fluid to the space between the valves, means for supplying piston-controlled cylinder pressure to the space between the valves and means for subjecting other opposed pressure areas on the valves to the pressures within the opposite ends of said cylinder.

6. In a pressure fluid motor, a cylinder having a bore, a piston reciprocable in said bore, and

fluid distribution means for supplying pressure fluid to said cylinder bore to effect reciprocation of said piston including means providing a valve chamber, relatively reciprocable valves mounted in said valve chamber and movable into abutting relation, said valves having sleevelike bodies and enlarged external flanges and cooperating to provide a space therebetween, passage means controlled by said valves respectively for supplying pressure fluid to the opposite ends of the cylinder bore, and means for shifting said valves into their different operating positions including means for connecting opposed pressure areas at the remote ends of the sleevelike valve bodies continuously to line pressure, means for supplying line pressure to the space between the valves, means for supplying piston-controlled cylinder pressure to the space between the valves and means for subjecting other opposed pressure areas on the valves to the pressures within the opposite ends of said cylinder.

7. In a pressure fluid motor, a cylinder having a bore, a piston reciprocable in said bore, and fluid distribution means for supplying pressure fluid to said cylinder bore to eifect reciprocation of said piston including means providing a valve chamber, relatively reciprocable valves mounted in said valve chamber and movable into abutting relation, said valves having sleevelike bodies and enlarged external flanges and cooperating to provide a space therebetween, passage means controlled by said valves respectively for supplying pressure fluid to the opposite ends of the cylinder bore, and means for shifting said valves into their different operating positions including means for connecting the opposed pressure areas at the remote ends of the sleevelike valve bodies continuously to line pressure, restricted passage means for supplying pressure fluid at line pressure to the space between the valves, means for supplying piston-controlled cylinder pressure to the space between the valves, means for subjecting other opposed pressure areas on the valves to the pressures within the opposite ends of said cylinder and piston-controlled passage means for subjecting said opposed pressure areas at the remote ends of the valve bodies to reduced cylinder pressure.

8. In a pressure fluid motor, a cylinder having a bore, a piston reciprocable in said bore, and fluid distribution means for supplying pressure fluid to and exhausting fluid from said cylinder bore for effecting reciprocation of said piston including means providing a valve chamber, cooperating, relatively movable, fluid distributing valves reciprocably mounted in said valve chamber, said valves movable into abutting relation in certain positions thereof and cooperating to provide a space therebetween, means forming passages leading from said valve chamber to the opposite ends of the cylinder bore and respectively controlled by said valves for conducting pressure fluid to the cylinder bore, and means for shifting said valves into their different operating positions including means for supplying pressure fluid continuously to thespace between said valves and passage means communicating with the cylinder bore and controlled by said piston for effecting a reduction in the pressure in the space between said valves.

9. In a pressure fluid motor, a cylinder having a bore, a piston reciprocable in said bore, and fluid distribution means for supplying pressure fluid to and exhausting fluid from said cylinder bore for effecting reciprocation of said piston including means providing a valve chamber, cooperating, relatively movable, fluid distributing valves reciprocably mounted in said valve cham ber, said valves movable into abutting relation in certain positions thereof and cooperating to provide a spacetherebetween, means forming passages leading from said valve chamber to the opposite ends of the cylinder bore and respectively controlled by said valves for conducting pressure fluid to the cylinder bore, and means for shifting said valves into their difierent operating positions including means for supplying pressure fluid continuously to the space between said valves, passage means communicating with the cylinder bore and controlled by said piston for effecting a reduction in the pressure in the space between said valves and means for connecting opposed. pressure areas on said valves continuously to line pressure. I

10. In a pressure fluid motor, a cylinder having, a bore, a piston reciprocable in said bore, and fluid distribution means for supplying pressure fluid to and exhausting fluid from said cylinder bore for efiecting reciprocation of said piston including means providing a valve chamber, cooperating, relatively movable, fluid distributing valves reciprocably mounted in said valve chamber, said valves movable into abutting relation in certain positions thereof and cooperating to provide a space therebetween, means forming passages leading from said valve chamber to the opposite ends of the cylinder bore and respectively controlled by said valves for conducting pressure fluid to the cylinder bore, and means for shifting said valves into their different operating positions including means for supplying pressure fluid continuously to the space between said valves, passage means communicating with the cylinder bore and controlled by said piston for effecting a reduction in the pressure in the space between said valves, means for connecting opposed pressure areas on said valves continuously to line pressure and means for subjecting other pressure areas on said valves to the pressures within the opposite ends of said cylinder.

11. In a pressure fluid motor, a cylinder, a

piston therein, and fluid distribution means for the motor including passage means for supplying pressure fluid to the opposite ends of the cylinder at the opposite sides of said piston respectively, a fluidsupply, valve means including a pair of cooperating, relatively movable, fluid distributing valves movable into abutting engagement and respectively controlling the flow of fluid through said passage means to the opposite cylinder ends, and means for shifting said valves into their different operating positions, one of said valves being held closed by the other valve abuttingly acting thereon, and said valves in certain positions thereof momentarily completely cutting off communication of both of said passage means With said fluid supply, and said means for shifting said valves including means for connecting opposed pressure areas on said valves continuously to pressure fluid at line pressure for urging said valves toward their positions of abutment.

' 12. Ina pressure fluid motor, a cylinder, a piston therein, and fluid distribution means for the motor including passage means for supplying pressure fluid to the opposite ends of the cylinder at the opposite sides of said piston respectively, a fluid supply, valve means including a pair of cooperating, relatively movable, fluid distributing valves movable into abutting engagement and respectively controlling the flow of fluid through said passage means to the opposite cylinder ends said valves cooperating to provide a space therebetween, and means for shifting said valves into their different operating positions, one of said valves being held closed by the other valve abuttingly acting thereon, and said valves in certain positions thereof momentarily completely cutting off communication of both of said passage means with said fluid supply, and said means for shifting said valves including means for connecting opposed pressure areas on said valves continuously to pressure fluid at line pressure for urging said valves toward their positions of abutment and means for connecting the space between the valves continuously to pressure fluid in said supply.

13. In a pressure fluid motor, a cylinder, a piston therein, and fluid distribution means for the motor including passage means for supplying pressure fluid to the opposite ends of the cylinder at the opposite sides of said piston respectively, a fluid supply, valve means including a pair of cooperating, relatively movable, fluid distributing valves movable into abutting engagement and respectively controlling the flow of fluid through said passage means to the opposite cylinder ends, said valves cooperating to provide a space therebetween, and means for shifting said valves into their different operating positions, one of said valves being held closed by the other valve .abuttingly acting thereon, and said valves in certain positions thereof momentarily completely cutting 01f communication of both of said passage means with said fluid supply, and said means for shifting said valves including means for connecting opposed pressure areas on said valves continuously to pressure fluid at line pressure for urging said valves to- Ward their positions of abutment, means for connecting the space between the valves continuously to pressure fluid in said supply and means under piston control for connecting the space between the valves to a reduced pressure within .the cylinder.

14. In a pressure fluid motor, a cylinder, 2.

piston therein, and fluid distribution means for the motor including passage means for supplying pressure fluid to the opposite ends of the cylinder at the opposite sides of said piston respectively, a fluid supply, valve means including a pair of identical valves arranged in coaxial relation and having sleevelike bodies and external flanges at the adjacent ends of the valve bodies, said valves cooperating to provide a space between the flanges thereof, passage means controlled by said valves respectively for controlling the flow of pressure fluid to the opposite ends of the cylinder, and means for shifting said valves into their diflerent operating positions including restricted passage means for connecting the space between the valve flanges continuously to live pressure fluid.

15. In a pressure fluid motor, a cylinder, a piston therein, and fluid distribution means for the motor including passage means for supplying pressure fluid to the opposite ends of the cylinder at the opposite sides of said piston respectively, a fluid supply, valve means including a pair of identical valves arranged in coaxial relation and having sleevelike bodies and external flanges at the adjacent ends of the valve bodies, said valves cooperating to provide a space between the flanges thereof, passage means controlled by said valves respectively for controlling the flow of pressure fluid to the opposite ends of the cylinder, and means for shifting said valves into their different operating positions including restricted passage means for connecting the space between the valve flanges continuously to live pressure fluid and means controlled by the piston for subjecting the space between the valve flanges to a reduced cylinder pressure.

16. In a pressure fluid motor, a cylinder, a piston therein, and fluid distribution means for the motor including passage means for supplying pressure fluid to the opposite ends of the cylinder at the opposite sides of said piston respectively, a fluid supply, valve means including a pair of identical valves arranged in coaxial relation and having sleevelike bodies and external flanges at the adjacent ends of the valve bodies, said valves cooperating to provide a space between the flanges thereof, passage means controlled by said valves respectively for controlling the flow of pressure fluid to the opposite ends of the cylinder, and means for shifting said valves into their different operating positions including restricted passage means for connecting the space between the valve flanges continuously to live pressure fluid, means controlled by the piston for subjecting the space between the valve flanges to a reduced cylinder pressure and passage means for supplying a continuous restricted flow of pressure fluid to opposed pressure areas at the remote extremities of the sleevelike valve bodies.

1'7. In a pressure fluid motor, a cylinder, a piston therein, and fluid distribution means for the motor including passage means for supplying pressure fluid to the opposite ends of the cylinder at the opposite sides of said piston respectively, a fluid supply, valve means including a pair of identical valves arranged in coaxial relation and having sleevelike bodies and external flanges at the adjacent ends of the valve bodies, said valves cooperating to provide a space between the flanges thereof, passage means controlled by said valves respectively for controlling the flow of pressure fluid to the opposite ends of the cylinder, and means for shifting said valves into their different operating positions including restricted passage means for connecting the space between the valve flanges continuously to live pressure fluid, means controlled by the piston for subjecting the space between the valve flanges to a reduced cylinder pressure, passage means for supplying a continuous restricted flow of pressure fluid to opposed pressure areas at the remote ends of the sleevelike valve bodies and means for subjecting opposed pressure areas at the remote sides of the valve flanges to piston-controlled cylinder pressures.

18. In a pressure fluid motor, a cylinder, a piston therein, and fluid distribution means for the motor including passage means for supplying pressure fluid to the opposite ends of the cylinder at the opposite sides of said piston respectively, a fluid supply, valve means including a pair of identical valves arranged in coaxial relation and having sleevelike bodies and external flanges at the adjacent ends of the valve bodies, said valves cooperating to provide a space between the flanges thereof, passage means controlled by said valves respectively for controlling the flow of pressure fluid to the opposite ends of the cylinder, and means for shifting said valves into their different operating positions including restricted passage means for connecting the space between the valve flanges continuously to live pressure fluid, means controlled by the piston for subjecting the space between the valve flanges to a reduced cylinder pressure, passage means for supplying a continuous restricted flow of pressure fluid to opposed pressure areas at the remote ends of the sleevelike valve bodies, means for subjecting opposed pressure areas at the remote sides of the valve flanges to piston-controlled cylinder pressures, and means for subjecting the opposed pressure areas at the remote ends of the sleevelike valve bodies to pistoncontrolled reduced cylinder pressures.

19. In a pressure fluid motor, a cylinder having a bore, a piston reciprocable in said bore, and fluid distribution means for supplying pressure fluid to the cylinder bore to effect reciprocation of said piston including means providing a valve chamber, relatively movable fluid distributing valves arranged in said valve chamber, a pressure fluid supply, said valves respectively controlling the flow of fluid from said supply to the opposite ends of the cylinder bore, said valves having pairs of opposed pressure areas, and

means for shifting said valves into their different operating positions including means for subject ing simultaneously one of said pairs of opposed pressure areas to piston-controlled cylinder pressure and means for subjecting the other pair of said opposed pressure areas in alternation to piston-controlled reduced pressure, one pressure area of said last mentioned pair and said first mentioned pair of pressure areas being subjected to piston-controlled pressures substantially simultaneously.

FRANK E. SINCLAIR.

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