US2546583A - Hydraulic apparatus - Google Patents

Description

March 27, 1951 E. H. BORN 2,546,583

HYDRAULIC APPARATUS Filed Feb. 10, 1945 2 Sheets-Sheet 1 FIG-1.

INVENTOR. Ellis H-Born A TTORNEY March 27, 1951 E. H. BORN 2,546,583

HYDRAULIC APPARATUS Filed Feb. 10. 1945 2 Sheets-Sheet 2 w V ..':.:.;g:g-. v I 67 Q 66 6 e3 e1 FIG-2 62 1" IG 3. FIG 4 W 4o 38 f ll|\\ 8 as 36 ge [364! l 1 7 l? I 5? 27 '5?)- f fi 5 I I W 54 V 4 as 40 as is 36 k' I l i I FIG 5 57 7 37 INVENTOR.

\ E1118 H- Born I BY E 45 zi wcjx KW T' ATTORNEY Patented Mar. 27, 1951 2,546,583 HYDRAULIC APPARATUS Ellis H. Born, Bexley, Ohio, assignor to The Denison Engineering Ohio, a corporation of Ohio I Application February 10, 1945, SerialNo. 577,290

17 Claims; (01.103-162) This invention relates to fluid pressure energy translating devices of the axial piston type which are capable of use either as pumps or motors.

When prior devices of this type were operated at high speeds and pressures a disagreeable noise occurred which to some degree was caused by the shock resulting from the sudden establishment of communication between piston chambers containing liquid at low pressure and ports containing liquid at high pressures and vice versa. The shocks resulting from such operations also caused undue wear and rapid deterioration of the device. One object of this invention is to provide a fluid pump or motor which will be capable of operation at high speeds and pressures without causing such shock and noise. An object of this invention also is to provide a liquid pump or motor having spaced valve and cam plates for cooperation with a cylinder barrel containing reciprocatory pistons disposed therebetween, the valve plate being formed with spaced ports and the cam plate having a piston controlling path with high and low points disposed in a definite relation to the ports in the valve plate, the device also having mechanism for causing relative movement between the cam and valve plates whereby the relation between the high and low points on the cam path-band the ports in the valve plate will be varied to minimize the shock caused by the sudden registration of the cylinder barrel chambers containing fluid at one pressure with the ports in the valve plate filled. with fluid at another pressure and the wear resulting therefrom.

Another object of the invention is to provide an axial piston pump or motor having a rotat- 7 able cylinder barrel with valve and cam plates at opposite ends thereof, one of such plates being supported for limited rotation in either direction froma normal position wherein a predetermined relation between ports in the valve plate and certain points on the cam plate exists so that when the cylinderv barrel starts to revalve ineither direction, relative movement between the valve and cam plates will take place with the resultv of varying such predetermined -relation and eliminating objections above noted.

A further object is to provide a pump or motor Company, Columbus,

piston pump or motor having a casing with inlet and outlet ports and a valve plate with arcuate openings communicating with such ports, the device having a cylinder barrel with chambers alternately connected with the inlet and outlet ports by the arcuate openings in the valve plate, the chambers receiving pistons which are reciprocated by a cam plate arranged at the end of the cylinder barrel to control the inflow and outflow of fluid to and from the chambers, the device also being provided with meansoperated by the fluid pressures in the inlet and outlet ports to move the valve plate and thereby vary the timing of the inflow and outflow with respect to the positions of the chambers and valve plate openings.

Another object is to provide an axial piston pump having a valve mounted for adjustment l relative to a cam member and plunger means for moving the valve plate, the latter having inlet and outlet ports the pressures of which are applied tothe plunger means so that the cam member will be adjusted in accordance with the pressures existing in such ports and when the direction of rotation of the motor or pump is reversed which, of course, will reverse the inlet and outlet ports in the valve plate, the latter will be adjusted accordingly.

A further object is to provide apump of the type mentioned in which the parts are so constructed that the time period in which the piston chambers are out of communication with the inlet. and outlet ports is materially lengthened and movement of the pistons iscaused or permitted during this time whereby the pressures in the piston chambers will be equalized with that in the ports with which the chambers are about to communicate. This arrangement serves to increase the efficiency of the device when employed as a pump, first by decreasing the resistance offered to the movement of the, pistons during the initial part of the stroke in which the piston chamber pressure is built up to the outlet port pressure and, second by utilizing the energy stored in the fluid to efiect rotation of the cylinder barrel during a portion of the time the piston chambers are moving from the outlet to the inlet port.

Further objectsand advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawings wherein a preferred form of embodiment of the invention is clearly shown.

In the drawings:

Fig. 1 is a vertical longitudinal view taken Figs. 6, 7, and 8 are elevational views of the" valve plate of a modified form of device showing the same in various stages of operation.

Referring more particularlytothe drawing, the

numeral designates the ainter motor to which the invention has been adapted. This 2,546,583 .1 III:

4 respect to the axis of rotation of the cylinder barrel. Due to the inclination of this surface, the pistons 31 will be reciprocated in the chambers 36 when relative rotary motion takes place between the cylinder barrel and cam. With the pump or motor in the position illustrated in Figs.

1 and 2 the points at which the pistons will be reversed in their reciprocations will be disposed in a vertical plane indicated by the dotted line 54,

- in Figs. 2 to 5 inclusive, passing through the axis of rotation of the cylinder barrel. By referrin to Fig. 2, it will be observed that the inlet and pump or motor has a casing 2| including a body- 22, a head 23 and an end cap 24 secured together to make a unit having. an internal chamber'25. This chamber receives a cylinder barrel 25 and valve and cam plates 21' and 28 respectively,

which are disposed at the, ends" of the cylinder barrel, the valve plate being arranged between the cylinder barrel 26 and the head 23. The

opposed ends of the head, and cylinder barrel have bearin surfaces 30 and'3l for sliding engagement with opposite sides of the valve plate The head 23 has acentral'opening 32' to receive a shaft 33 which is iournalled in bearings 34 mounted in the head. The inner end of the Y's'hait 33 has a splined connection 35 with the cylinder barrel 26 so that when the shaft is revolved, similar movement'will be imparted to the cylinder barrel. Cylinder barrel 26 is formed with a plurality of axially extending chambers 3B for the slidable. reception of, piston elements 31, the reciprocation of which, in the chambers 33, serves to govern the inflow and outflow of fluid of 'thepistons in the chambers 35, each is provided witha spherical head 43 to which is unif v ersall'y connected '9'. bearing shoe 44, the latter vfmembers being .in'sliding. engagement with the I surface l'S. of the cam member 28. The engagement between the shoes and the cain surface 45 is maintained by a. retainer plate H5v which surrounds the. shoes 44. andfengages shoulders 41 formed thereon, the plate beingurged toward 7 the cam by a plunger 48 movably positioned in w a sleeve 49 which is disposed-in asocket 5!] formed in the inner end of'the shaft 33.

Coil sprin 5] is' positioned between. a wall of the plunger 48 and afia'nge52. formed at 'the .inner end-of the sleeve 49... This spring tends to force the plunger out of the sleeve thus causing the former to exert a yieldableforce onthe plate 46. The outer end of the. sleeve 49' has an annular flange 53v formed thereon, which flange engages 'I'the outer end of the cylinder barrel 2'6 and tends 'to move the same toward the valve plate 21.

Spring 51 thus serves two functions, first, that fof'maint'aining the bearing, shoes 44 in engage n ent with the-cam surfaceiand second,,the maintenance of the cylinder barrel 26 in sliding engagement with the valveplateffl.

From an inspection of Fig.1. it will be observed its t e s r a e 5- fihe el e e wh n.

the bearin shoes 44' are engaged'is inclinedwit-h' Lil) outlet ports 39 and are symmetrically disposed about this plane when the valve plate 21 is'normally positioned. With the parts thus arranged, their relative positions will be as illustrated diagrammatically in the developed view in Fig. 3.. In this Fig. as well a Figs. 4 and 5, the bearing shoes have been omitted for convenience in illustrating and understanding the invention. I v From Fig. '3" it will be seen that when the'cylinder barrel 26' is so located that the longitudinal axis of a chamber as therein is disposed in the plane 54, the piston 31' in that chamber will engage the cam surface at a point where the direction of movement of thepi'stons' in the cylinder barrel is reversed, this may be eitherthe low or high point of the cam. In Figs. 3 to 5 inc., the low point of the cam has been illustrated. At this time the particular chamber 36 will be in communication with neither'the inlet nor'outletports. As the cylinderbarrel revolves in the direction ofthe arrow 56 in Fig. 3 the cam surface will'move the piston inwardly and apply force to the fluid in this chamber; When the open end of the chamber reaches the outlet port, the fluid will be expelled from the chamher into the port "by the inward movement of the piston. When the pump is in actual operation the pressure in chamber 36 may be much lower than that in the outlet port and if so a shock will resultwhen the communication is established between the port and the chamber.

' This shock will be transmitted to various parts of the pump or motor and'cause undue-wear as well as objectionable, noise; To avoid such shock I it has beenfound desirable to rotate or index 'sure, the valve plate has been made adjustable motion of the latter member is limited, however,

either the port plate or the carn plate to vary the relation therebetween In the present discloto secure this indexing.

In the form of the invention shown in- Figs. 6 to 8, inclusive, the valve plate 21A is so mounted that when the cylinder barrel revolves; the initial movement'thereofin either direction will cause similar movement of; the valve plate. The

by a stop pin 51 which projects from tre head23 into a slot 58 formediin the, valve plate 21A.

The slot 58 is ofsuch length and the pin lil'so positioned'that the valveplate will move. onlythe distance required to cause the ports therein to be. so positioned relative to the cam surfacethat benoted that this self-indexing type of port plate is only suitable for use in a'fiuid pump.

In some instances itmay be found desirablejto positively adjuster index the valve plate ojrto use an indexed valve. plate in a fluid motor. "To

accomplish thispos'iti've" adjustment "the valve plate is provided with a projection 60 which is disposed in the path of movement of a pair of oppositely directed plungers 6| and 62. These plungers are positioned for sliding movement-in sockets 63 and 64 formed in the pump body 22'. Coil springs 55 are disposed in the plungers, one end of each spring engaging the inner end wall of the plunger while the opposite ends of these springs engage adapter members 66 which are slidably positioned in the sockets 63. These adapter members are adjustable through the manipulation of screws 61 which are threadedl'y carried by plugs 68 inserted in the outer ends of the sockets 63. The adjustment of the screws 61 serves to vary the force of the springs-B which normally tend to move the valve plate to the normal position shown in Fig. 2. The casing is provided with passages II and 12 to establish communication between the inner portions of the sockets 63 and 64 and the inlet and outlet ports in either the valve plate 2! or the head 23. It will be seen that when the pressure is increased in either port 39 or 40 this pressure will be transmitted through-passages H or 12 to the socket connected therewith and will be applied to the inner surface of either plunger 6! or 62. The

force of this fluid pressure will cause the valve plate to revolve about the axis of rotation of the cylinder barrel and thus vary the relation between the ports. in the valve plate and the cam =28. It will be observed that when the device is and 12 to the respective plunger which pressure will cause the valve plate to be revolved in the proper direction to so dispose the port containing pressure relative to the cam surface that the fluid pressure in each chamber 35 will be increased until it is substantially equal to the pressure existing in the outlet port before com- :munication between the chambers and theport is "established.

As the piston chambers move away from the high pressure port, they will contain fluid at the pressure existing in such port. The cam surface will then cause the pistons to move outwardly thus reducing the pressure in the chambers until communication is established between these chambers and the low pressure port. Any noise incidental to the establishment of communication between the piston chambers and the low pressure port will thus be minimized due to the neur't'ralization of pressures in the piston chambers and the ports in the valve plate.

" vention.

When the device is operated as a fluid motor,

' fluid under pressure is supplied to one of the ports 39 and 4!). chambers then in communication with the port containing fluid under pressure and will apply This fluid will flow into the force to thepistons therein to move them to- 'ward the cam plate. As the pistons are forced toward the cam plate they will tend to slide 'along' the plate toward the low point of the cam 'and. cause the rotation of the ylinder barrel in pressure.

the usual manner. 'At'this' time fluid pressure will also be conducted to the socket 63 or 64 connected with the port containing the fluid under pressure and the piston therein will impart movement to the valve plate in the same manner described above. When the device is employed as a motor, however, the valve plate is indexed in a direction opposite to that in which the cylinder barrel revolves. The communication between the pressure port and piston chambers is thus interrupted on the power stroke before the pistons reach the low point on the cam. The continued outward movement of the pistons after this communication is interrupted causes a reduction in the pressure on the fluid to that in the low pressure port thereby eliminating any shock when communication is established.

One of the advantageous results of the present construction is an increase in efliciency over that secured in previous devices of this character. This increased eiflciency is due to a reduction of the power required to raise each piston chamber charge of fluid from inlet port to outlet port pressure, and the utilization of such pressure to effect a driving action of the cylinder barrel. In the present device, the width of the sealing surface of the valve plate between adjacent ends of the inlet and outlet ports is considerably greater than the length of the piston chamber ports. Communication between the chambers and one or the other of theIports is therefore interrupted for a longer period of time than generally occurs in devices of this character.' During one interruption of this communication the pressure in the piston chamber is raised from inlet port pressure to outlet port pressure. During the other interruption the pressure in the piston chamber is lowered from outlet port to inlet port pressure. This equalization of pressure occurs in both instances before communication is established between the piston chamber and the respective port. It will be seen that at no time during the building up of pressure in the piston chambers preparatory to connection with the outlet port are the pistons operating at a pressure as great as the outlet port pressure. This method of operation is in marked contrast with that of conventional devices of this character where the piston chambers are connected with the high pressure port while the fluid in the former is at low pressure. In such devices the full outlet port pressure is applied to the pistons during the elevation of the fluid in the piston chamber from inlet to outlet port There is thus a decrease in the power required in the operation of the improved device of the present invention.

The energy utilized in raising the fluid from inlet to outlet port pressure is not wasted in the present pump but is employed to assist in the rotation of the cylinder barrel. It will be apparent that as any piston chamber leaves the outlet port it will contain fluid under the pressure of such port. The ports are so constructed that when the piston and piston chamber reach the high point of the cam, communication between the piston chamber and the outlet port will be terminated. The tendency of the fluid to expand will, therefore, cause the piston to coact with the cam as in a fluid motor and impart a rotating force to the cylinder barrel. Since some of the energy expanded in rotatin the cylinder barrel to raise the pressure of the fluid is thus employed to drive the device, the. efliciency thereof will be increased. i

7. While the term of embodiment. of the. present invention as. herein disclosed" constitutes; a pre-" ferred form, it is tobe understood that. other forms. might be adopted, all. coming within the scope of the, claims which: follow-..

' I claim:

1. A fluid pressure energy translating: device comprising a casing having a chamber; a head with inlet and outlet ports at one end of said chamber; a valve disk disposed in engagement with said head and having limited rotary motion relative thereto, said disk having a pair of arcuately-shaped ports spaced on opposite sides of a plane normal to a face of said disk passing through the axial center thereof, said portscommunicating with said inlet and outlet. ports; a member on said head for limiting the rotary movement or saiddisk; a cylinder barrel having one. end in engagement with said disk, initial rotation of said cylinder barrel in either direction serving to move said valve disk the same direction to the degree limited by said member; piston means disposed for movement in said cylinder barrel; a cam plate. at the end of said. cylinder barrel to control the movement ofsaid pistons, said camplatehaving a cam surface with points at which the direction of movement of said pistons is reversed, the rotary movement ,of said valve serving to change the relation of the arcuately-shaped port therein to the piston reversing points on said cam surface.

2. A fluid pressure. energy translating device comprising a casing having a chamber; a head atone end of said chamber, said head having inlet. and. outlet. ports; a valve plate engaging said head and being supported for limited rotation relative thereto, said plate having a pair, of arcuately-shaped ports, said ports communicating with. the. inlet and outlet ports in said head; a pin projecting from said head into an opening in said valve plate, said openin being of such size and shape as to. permit limited rotation of. said valve plate; a cylinder barrel engaging said valve plate andimparting rotary movement thereto upon initial rotation of the former in either direction; piston means: movably supported in said cylinder barrel; a plate, disposed at I the. end of. said cylinder barrel, said plate having direction of movement of said. pistons is reversed as toreduce. the noise of operation of the device. 5

3. In a fluid pressure energy translating device, a. member having inlet and outlet ports; a valve .diskengaging. said member, said disk having arciiately shaped inlet and outlet ports communicating with the inlet. and outlet ports in said member and being supported for limited rotary movement in the plane of the disk; and a cylinder barrel disposed for rotation in engagement. with said disk, initial rotary movement of said cylinder barrel in either direction serving to impart limited movement in the same direction of rotation to said valve disk.

i. In a fluid pressure energy translating device,

a member having inlet and outlet ports; a valve disk engaging said member, said disk having arcuately shaped inlet and outlet ports communicating-with the inlet and outlet ports in said member and being supported for limited rotary movement in the plane of the disk; a cylinder barrel disposed for rotary sliding engagement with said disk. rotary movement. of; said cylinder barrel in either direction tending to; impart limited movement in the. same direction of m.- tation to said valve disk; and. means, for. limiting. the extent of rotation of said valve disk.

5. In a fluid pressure energy translating: device, a. member having inlet and outlet ports; a. valve disk, engaging said member, saiddisk havingercuatelv ed inlet and outlet. ports. communicating with the inlet: and outlet ports, in said member: and being, supported for rotary-f movement inthe plane of the disk; fluid pressure resp nsive, means for imp r g l r y" movement to said. disk; a cylinder barrelsup portedior rotary movement in. slidingv engage-.-v ment. with said. disk; piston means movably sup ported. in said cylinder barrel; and a. cam plate adjacent said cylinder barrel to control-a the movement of. saidpiston means, rotary motion of said disk serving. to vary the relation of the ports in. said disk to the pistonv movemen reversing points. on. said cam plate.

6. Ina fluid pressure energy translating device. a. member having inlet and outlet ports; a valve disk engagingsaid member, ,said.disk havinearr cuately shaped inlet and. outlet ports communir eating with. the. inlet: and. outlet ports. in; said member, and being supported for. rotary move mentin theplaneof saiddisk; fluid pressurerea sponsive means. for imparting limited. rotary movement ineither direction to said disk. means for admitting fluid from one of said inlet; and outlet ports, to said fluid pressure resonsive means to eifectv the movement. of said disk; a. cylinder barrel disposed. for rotation in engagement-with said disk; piston means movably'reeelved.by'saiii cylinder barrel; and a cam member disposedadjacent said cylinder barrel to control the movement of said piston means, the rotary movement. of said valve disk serving to vary the timingv of the piston motion relative to the ports in said valve disk; i

7. In a fluidpressure energy translating devil; a member having inlet and outlet ports; a: valve disk engaging said member, said disk having-arcuately shaped inlet and outlet ports. communieating with the inlet and outlet ports in said member and being supported for rotary: movement inthe plane of said disk; fluid pressure. responsive means for imparting limited rotary movement in either-direction to said disk, means connecting said pressure responsive means with, said inlet and outlet ports; a cylinder barrel dis posed for rotation in engagement with saidd-isk; piston means movably received by said cylinder barrel; and a cam member-disposedadjacent-said cylinder barrel to control the movement of said piston means, rotary movement of said valve disk serving to varythe timing of the piston motion relative to the ports in said'valve disk.

' 8. In a fluid pressure energy translating device, a member having inlet and outlet ports;- a valve disk engaging said member, said disk having arcuately shaped inlet and outlet ports communicating with the inlet and outlet ports in said member and being supported for: rotary movement in the plane of said disk; a pair of fluid-pressed piston members for imparting limitedrotarymovement in either direction to said disk; means for conducting fluid from said inlet and outlet ports to said pistons: acylinder'baln reldisposedfor rotation in engagement with said disk; piston means-movablv received by said cylinder barrel; and a cam'memberwdisposedi adiae cent said cylinder barrel to control the meme 9 ment of the piston means in saidcylinder barrel, the rotary movement of said vvalve disk serving to. .vary the timing of the motion of the piston" means in the cylinder barrel relative to the ports in'said valve disk. '9. A fluid pressure energy translating device comprising a casing having a chamber; a valve plate 'in'said chamber, said valve plate having arcuately shaped'inlet and outlet ports disposed on opposite sides of a plane disposed normal to the face of the valve'plate and coinciding with the axial center thereof; a cam member spaced from said valve plate, said cam member having a camsurface with high and low points normally d ed in ea drle e c linder el. ro

bly disposed between said cam member and valve plate; piston means disposed for reciprocation in said cylinder barrel, said cam surface controlling the movement of said pistons; and fluid pressure operated means for causing relative movement between said cam member and said valve plate about the axis of rotation of said cylinder barrel whereby the relative positions of the high and low points in said cam surface and the inlet and outlet ports will be changed.

. 10. In a fluid pressure energy translating device, a stationary member having inlet and outlet ports; a valve disk engaging said member, said disk having arcuate inlet and outlet ports in communication with the ports in said member; a cylinder barrel supported for rotation with .1 surface thereof in frictional engagement with said disk, rotation of said cylinder barrel tending to impart limited movement in the same direction of rotation to said disk; means on said stationary member for limiting the extent of movement of said disk, said means permitting a partial turn of said disk when the direction of rotation of said cylinder barrel is reversed; piston means disposed for reciprocation in said cylinder barrel; and cam means for controlling the reciprocation of said piston means, the limited movement of said valve disk serving to vary the timing of the reciprocatory movements of said piston means relative to the ports in said valve disk.

11. In a fluid pressure energy translating device, a cylinder barrel having a bearing surface at one end and a plurality of chambers opening to said surface; a valve plate engaging said bearing surface, said valve plate having inlet and outlet ports spaced equally on opposite sides of a plane disposed normal to a face of said valve plate and passing through the axial center thereof; piston means slidably disposed in the chambers in said cylinder barrel; and a cam plate at the end of said cylinder barrel opposite said valve plate, said cam plate controlling the movement of said pistons, one of said plates having limited rotation about the longitudinal axis of said cylinder. barrel to vary the time of movement of said pistons relative to the position of said inlet and outlet ports.

12. In a fluid pressure energy translating device, a cylinder barrel having a bearing surface and a cam'plate at the endof said cylinder barrel.- opposite said valve plate-said cam plate having. a cam surface symmetrical about said plane,.-said cam surfacecontrolling the movement ofs'a'id pistons, the rotation of said valve plate serving" to vary the time of movement of said pistons relative to the position of said inlet and outlet ports.

13. In a fluid pressure energy translating device, ,a valve plate; construction comprising a member having inlet and outlet passages; a disk engaging said member, said disk having arcuate inlet and outlet ports positioned on opposite sides of a plane disposed. normal to aface-of said disk and passing through the axial center there-r. of; means actuated by fluid pressure to impart limited rotation to said disk about its longitudinal axis to change the relation of said ports to said plane; and means for returning said plate to normal position to restore the initial relation of said ports and plane when the fluid pressure is reduced.

14. In a fluid pressure energy translating device, a valve plate construction comprising a member having inlet and outlet passages; a disk engaging said member, said disk having arcuate inlet and outlet ports positioned on opposite sides of a plane disposed normal to a face of said disk and passing through. the axial center thereof; means for adjusting said disk about its longitudinal axis to vary the relation of said ports to said plane, said means having springpressed plungers tending to hold said disk in a normal position; and means for applying fluid under pressure to either of said plungers to effeet the adjustment of said disk.

15. In a fluid pressure energy translating device, a valve plate construction comprising a member having inlet and outlet passages; a disk engaging said member, said disk having. arcuate inlet and outlet ports positioned on opposite sides of a plane disposed normal to a face of said disk and passing through the axial center thereof; means for adjusting said disk around its longitudinal axis to vary the relation of said ports to said plane, said means having oppositely acting plungers; and means for applying fluid at inlet port pressure to one of said plungers and at outlet port pressure to the other plunger.

16. In a fluid pressure energy translating device, a valve plate construction comprising a member having inlet and outlet passages; a disk engaging said member, said disk having arcuate inlet and outlet ports positioned on opposite sides of a plane disposed normal to a face of said disk and passing through the axial center thereof; means for adjusting said disk to vary the relation of said ports to said plane, said means having oppositely-acting spring-pressed plungers tending to move said disk to a normal position; and means for applying fluid at inlet port pres sure to one of said plungers and at outlet port pressure to the other.

17. In a fluid pressure energy translating device, a member having inlet and outlet ports; a valve disk engaging said member, said disk having a pair of arcuately shaped inlet and outlet ports of substantially equal length communicating with the inlet and outlet ports in said member and being supported for pivotal movement in the plane of the disk, said disk being normally disposed with the arcuate ports spaced equally on opposite sides of a plane extending normal to the face of the disk and passing through the axial center thereof; means for imparting limited rotary movement to said disk to vi'y tlippositions of said ports rlative to said plane; a; cylinder ha'rrel suppopted ior rotary movement in sliding engagemntwith said disk; piston means movably supp z-ted .in said cylinder'barrl; anda cam plate adjacent 'saidcylinder barrel to control the movement of said p18- ton means.

H. BORN.

REFERENCES CITED Th8 "following .rferenceS are "of record in 13hr: file of this patent:

Numbei Number UN'rrED sums PA'I'Em's "Nam Date Carey Dec. '16, 1913 Pratt Nov. 2, 1915 Rayburn Aug. 3, 1920 Trowbridge Feb. 21, v1922 Sorenson Sept. 8, 1931 Ferris Aug. 14, 1934 Benedek Mar. 30, 1937 Zimmerman July 7, 1942 FOREIGN PATENTS Country. Date Switzerland 1907 France 1938

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