US1989117A

US1989117A - Plunger pump

Info

Publication number: US1989117A
Application number: US430867A
Authority: US
Inventors: Ernest J Svenson
Original assignee: Individual
Current assignee: Babcock and Wilcox Co
Priority date: 1930-02-24
Filing date: 1930-02-24
Publication date: 1935-01-29
Anticipated expiration: 1952-01-29

Description

`Ian. 29, 1935. E, 1 SVENSON 1,989,117

PLUNGER PUMP Filed F'eb. 24, 1930 6 Sheets-Sheet l 1f@ 66 ZZ Jan. 29, 1935.

E. J. svENsoN 1,989,117

.PLUNGER PUMP Filed Feb. 24, 1930 3 Sheets-Sheet 2 Jan. 29, 1935.

E. J. svENsoN 1,989,117,F

PLUNGER PUMP v Filed Feb. 24, 1930 s sheets-sheet s 4 Q N *u n N v 'Se N @7M-@fw S- for example, oil, may be ern Patented Jan. 29, 1935 PATENT OFFICE- PLUNGER PUMP Ernest J. Svenson, Rockford, Ill. Application February 24, 1930, Serial No. 430,867

23 Claims.

My invention relates generally to propelling devices and more particularly to improvements in means for reciprocating radial pistons.-

Experience has shown that a fluid medium, as

propelling instrumentality,

ployed as an effective and this fact is evidenced by the ever increasing demand in certain fields for machines which propelling mechanisms. One

are equippe d with fluid of the fields, in

Which hydraulic propelling mechanisms are being increasingly employe dustry wherein tool suppor like are being activa propelling devices.

ting

ally comprise a circuit which is d, is the machine tool incarriages and the ted by means of f hydraulic These hydraulic devices ususupplied with a fluid medium by a pumping mechanism, which in many instances comprises placement pump. The proper fluid circuit is dependent upon a rotary fluid disfunctioning of the the operating efficiency of the fluid supplying mechanism or pump, and the types of fluid propelling devices heretofore employed, in many instances have presented numerous diiculties and disadvantages. One of the outstanding difficulties which has been experienced in connection devices is that of fluid slippage slippage results from the fact mechanisms have been so desi portion o into the operative portion of with these pumping or leakage. This that the pumping gned that a large f the fluid, which should be displaced the uid circuit,

leaks or by-passes through restricted openings in the valve and other pump ttings.

the fluid propelling efficiency of Obviously, the pump is greatly reduced as a result of this uid slippage, and experience has shown that the efliciency of the pumping mechanism decreases as the fluid pressure increases because increased pressure causes increased slippage. In addition to the above mentioned power losses resulting from slippage, injurious increases in temperature of the fluid also result from the passage thereof through these rel strictedopenings, and this development of heat is particularly n livering fluid at high pressur vantages also have been experience oticeable when the pump is de- Other disadd as a result of' the cumbersome, complicated, and expensive structural features in pumping devices which heretofore have been available.

It is one of the primary objects of 'my present invention to overcome the above mentioned and other disadvantages and inconveniences which have been experienced heretofore in connection with the use of fluid propellin variable displacement pumps,

g devices, such as and to` this end I propose to provide a simple, compact, durable, and efficiently operable fluid propelling device.

My invention contemplates the-provision of a fluid propelling mechanism which is adapted to receive uid at a given pressure and to deliver said fluid at increased pressure without subjecting said fluid to by-passing or leakage, which would have a tendency to decrease the propelling eflciency of the device.

Another object of my invention is to provide a fluid propelling mechanism or pump which may be very easily attached to or detached from a mounting or machine with a minimum amount of effort and skill, and to this end I propose to provide a device which is comparatively light inweight, of small bulk, and at the same time capable of developing and withstanding high fluid pressures.

Still another and more specic object of my invention is to provide a device as above set forth which will preclude the necessity of revolving pistons or plungers about a given axis as has been done heretofore, and to this end I propose to provide a stationary block in which a plurality of pistons or plungers may be reciprocated for the purpose of receiving and displacing a fluid medium.

A further object of my/invention is to provide an efliciently operable rotary means for actuating the above mentioned plungers, and in combination therewith a practical and simple means, whereby said rotary means may be accurately and positively displaced for varying the stroke of said plungers. In addition to the above mentioned advantageous characteristics, my invention contemplates the provision of an improved, highly efficientv rotary valve arrangement for directing uid to and from the above mentioned plungers, which valve is so arranged as to positively prevent the deleterious slippage or by-passing of fluid along the bearing surfaces thereof, and is so connected with an eccentric driving means as to be free from side thrusts.

My invention also contemplates the provision of means, whereby reciprocation may be imparted to the radial pistons or plungers through theagency of an eccentric rotary member without subjecting said plungers to side thrust or wear.

The above mentioned and numerous other obf jects and advantages will be more apparent from the following detailed description of a device which is representative of one embodiment of my invention and which is disclosed in the accompanying drawings, wherein- Figure 1 is a central longitudinal sectional view of a fluid propelling device, the view being taken substantially along the line 1--1 of Figure 2, certain parts thereof, such as the rotary valve and other parts associated therewith being shown in elevation for the purpose of more clearly disclosing the invention;

Figure 2 is a transverse vertical sectional view taken substantially along the line 2-2 of Figure 1;

Figure 3 is a similar transverse sectional view 'taken along the line 3--3 of Figure 1;

Figure 4 is a vertical transverse sectional view taken substantially along the line 4--4 of Figure 1;

Figure 5 is a longitudinal sectional View shown partly in elevation, said view being taken substantially along the line 5 5 of Figure 2;

Figure 6 is a perspective detail view of the rotary valve shown in Figures 1 to 5 inclusive;

Figure 7 is a reduced fragmentary transverse sectional view of a fluid propelling mechanism which is equipped with radial plungers of modified construction, said plungers bearing directly upon the eccentrically adjustable rotary means; Figure 8 is a fragmentary perspective view of the sleeve portion of the rotary driving means;

Figure 9 is a perspective view of the device which is slidable within the sleeve portion of Figure 8 for eccentrically adjusting the rotary driving means; and

Figure 10 is a perspective view of the eccentrically adjustable portion of the driving means.

Referring now to the drawings more in detail, wherein like numerals have been employed to designate similar parts throughout the various figures, it will be observed that one embodiment of my invention includes a cylinder block or stator denoted generally by the numeral 12. This block 12 includes an annular bearing 14 and a larger annular section 16, which is provided with a plurality of radial chambers 18 for accommodating radially reciprocable plungers or pistons 20. At the outer-.extremity of each of the radial chambers 18 I provide a. threaded plug member 22 which is adapted to be iremoved to permit of the removal or insertion of the pistons 20. The outer portions of the radial chambers 18, which I have designated by the numeral 18a, communicate with companion passageways 24 provided in the block or stator 12. The inner extremities of these passageways 24 communicate with companion radial ports 26 provided in a bearing or bushing 28 mounted within the annular bearing support portion 14 of the stator. Fluid or oil is adapted to be timingly directed into and away from the passageways 24 through the agency of a rotary valve mechanism which I have designated generally by the numeral 30.

Rotation is imparted to the rotary valve mechanism 30 by means of an eccentrically adjustable driving means 32,v later to be described. At this stage of the description of my improved fluid propelling mechanism, it should be understood that the rotation of this eccentrically positioned driving means 32 causes the plungers 20 to be reciprocated within the stator, and the valve mechanism 30 is so arranged as to effect the delivery of fluid at a given pressure to the chamber sections 18a during the intake stroke of each plunger, and to effect the displacement of fluid from said chamber sections during the compressing or discharge stroke of each plunger. This rotary valve mechanism 30 includes a rotary member 34 which is provided with a tapered bearing surface, the smaller extremity of the valve member 34 being positioned at the inner end adjacent the driving means 32. A close running fit is provided between the adjacent surfaces of the member 34 and the bushing 28, suicient clearance being provided to insure the required lubrication of the parts. The valve member 34, as clearly shown in Figures 3, 5, and 6, is provided with oppositely disposed

peripheral ports

36 and 36a. The valve port 36 is connected by means of a pair of passageways 38, Figure 5, with a chamber 40 which is enclosed within a casing 42. This casing 42`is sealed against the end surface of the stator section 14 by means of suitable screws 44, Figure l. An anti-friction thrust bearing 46 is positioned within the chamber 40, as clearly shown in Figures 1 and 5, and is interposed between the outer end of the valve member 34 and a thrust member 48. This thrust member bears against an adjustable centrally positioned abutment screw 50. Thus it willbe apparent that longitudinal adjustment of the valve member 34 may be accomplished by manipulating the screw 50, which is locked in position by means of a suitable nut 52. The end chamber 40 communicates with a suitable source of low pressure uid supply (such as a suitable gear pump, not shown), by means of a pipe line 54, Figure 1. Fluid may also be supplied, by restricting an orice, which restriction will give suicient pressure to charge the pistons.

From the foregoing, it will be understood that uid, such as oil,'which is delivered from the pipe 54 into the end chamber 40 passes between the balls 56 of the bearing 46, and thence through the passageways 38 and into the valve port 36. The timing of the plunger movements is such that the fluid from the valve port 36 is always directed into the chambers 18a during the intake stroke interval of each plunger. On the other hand, the peripheral valve port 36a is so positioned as to communicate with the chambersections 18a during the compressing stroke interval ofA the plungers, and enables said compressed fluid to be Withdrawn through the passageways 24 and companion ports 26 and thencefthrough passageways 58, Figures 1 and 5, which communicate with an annular valve port 60. This annular valve port 60 communicates with a pipe line 62, which may be connected with a fluid actuated mechanism (such as a machine tool carriage, not shown). Thus, fluid at a given pressure received from the pipe line 54 is directed through the valve port 36, the stator passageways 24, and thence to their companion chamber sections 18a. The pressure of the fluid in these chamber sections is increased through the outward movement of the plungers, and subsequently displaced in a reverse direction through said stator passageways and into the valve port 36a, which communicates with the high pressure pipe line 62. In other words, during the complete reciprocation of each plunger, uid is taken into the chamber section 18a at a given pressure, subjected to increased pressure and displaced at said increased pressure into the pipe line 62.

Attention is directed to the advantages which necessarilyflow from the tapered arrangement of the valve member 34. By having this tapered arrangement, the leakage of fluid into the chamber- 64 within the stator 12 is positively prevented. My construction is to be clearly distinguished from the usual cylindrical valves which have heretofore been employed. These conventional cy- CII body, and have permitted the fluid to leak or slip through the annular clearance which is presented between the peripheral surface of the valve and' supporting bearing. The leakage or by-passing of uid through the restricted clearance space materially reduces the propelling efficiency of a pump and causes the fluid to become overheated. My improved rotary valve construction provides a fluid seal at one extremity of the valve member, and any slight leakage which might take place at the opposite extremity thereof is counteracted by the pressure of the oilwithin the end chamber 40. Any fluid.which might pass from the clearance space between the valve member 34 and the bushing 28 into the end chamber 40, is retained in the fluid circuit and redirected through the valve passageway 38 into association with the plungers. This unique arrangement eliminates fluid slippage, and hence materially increases the propellingiiiciency of the mechanism.

It is also to be noted that the rotary valve mechanism 30 is not employed as a support, but is self-contained within the bushing 28 and is not subjected to side thrusts which are occasioned when rotary valves are employed as a means for supporting pump structures. In other words, my improved rotary valve construction is one in which a rotary valve member does not provide a support, but, on the other hand, is supported within a rigid section of the pumping mechanism, such as the stator- 12.

Attention is now directed to my improved mechanism 32 which serves as a means for imparting reciprocation to the plungers 20, and as a means for imparting rotation to the valve mechanism 30. This driving mechanism 32 includes a sleeve member or Journal 66 which is supported by means of

anti-friction bearings

68 and 70 within a pump casing or housing 72. Peripherally supported and keyed to the sleeve or journal 66 is an annular gear 74, which is adapted to be driven by means of a companion gear '76 connected to any suitable driving mechanism (not shown). To obtain a clear understanding of the structural characteristics of this driving mechanism 32, reference is made to the disclosures in Figures 1, 8,9, and

10. In Figure 8 the sleeve or journal 66 is shown in perspective, and it will be seen that said sleeve is provided with a transverse slot '18 and a communicating slot of smaller width 80, which slots are adapted to receive sections '78a and 80a respectively of a coupling member, which I have designated generally by the numeral 82, (see Figure 10). The-coupling member 82 is driven by the sleeve 66 and is adapted to be shifted within predetermined limits transversely of said sleeve in order to eccentrically position an anti-friction annular driving member or ring 84. This ring 84 has an anti-friction mounting supported by the reduced end section 86 of the coupling member, and the peripheral surface of said ring engages the inner surfaces of a plurality of pivotal fingers 88. Each of these fingers is companion to andengages the inner end of one of the plungers 20, as clearly shown in Figure 2. The invention contemplates the use of fingers which differ in shape from the ilngers 88.

The outer extremity of the reduced end section 86 of the coupling 82 is provided with an integral elongated driving tongue 90, which is adapted to be received by a companion slot 90a extending transversely of the inner end of the valve member 34, as clearly' shown in Figures l and 5. It

is to be noted that the horizontal axial or center line which passes through the driving tongue 90 is co-incident with the axis of the coupler means 82, which includes the reduced cylindrical section 86. Thus, if the axis of the coupler` means 82 is co-incident with the axis of rotation of the driving sleeve 66, the anti-friction ring 84 will not be eccentrically positioned, and hence no movement will be imparted to the plungers. Under such conditions, the above mentioned axis of rotation will be co-incident with the axis of the rotary valve member 34. In Figure 2 I have designated the xed axis of rotation of the driving sleeve 66 by the letter A and the axis of the coupler means 82 by means of the letter B. Consider now that the coupler 82 is shifted from a coaxial position with respect to the driving sleeve 66 to the eccentric position shown in Figure 2, and that rotation is imparted to the sleeve 66 in a direction indicated by the arrows in Figure 2. Obviously, this results in the eccentric positioning of the ring 84 with respect to the xed axis of rotation of the sleeve 66, thereby causing the plungers 20 to be completely reciprocated during each complete rotation of the driving means 32. Shifting the ring 84 as above described causes the coupler member 90 to be shifted in the same direction within the companion groove 90a of the rotary valve member.

As a result of this tongue and groove connection, namely, the connection between the driving tongue and groove 90a, the rotary valve member 34 is not subjected to side thrusts. In other words, the centrifugal forces which are set up within the driving means 32, as a result of the eccentric positioning of the coupler means 82are not transmitted to the rotary valve, because these forces act in the direction indicated by the arrow,

Figure 1, which isin line with the sliding movement of the driving tongue 90 within the groove 90a. By means of this coupling arrangement, the valve 34 is rotated without experiencing any wear from side thrust forces and the like. Rotary valve mechanisms which have been employed heretofore, have been subjected in many instances to considerable side thrust forces as the result of the rotation of associated pump elements.

The eccentric adjustment ofthe ring 84 within the stator housing is accomplished through the agency of a member 92, which is longitudinally slidable within the driving sleeve or journal 66. The inner extremity of the member 92 is provided with a reduced cylindrical extension 94, which `is-angularly disposed with respect to the axis of the sleeve 66 and extends into a companion cylindrical recess 96 provided in the body of the coupler means 82, as clearly shown in Figures 1, 9, and 10. The extension 94 is so positioned within the coupler means that, when the member 92 is longitudinally shifted within the sleeve 66, the sections '18a and 80a of the coupler means will be moved within their companion slots '78 and 80 respectively. In other words, longitudinal movement which is imparted to the member 92 will cause the plunger actuating ring 84 to be eccentrically positioned.

I provide a micrometer adjustment for the member 92, which includes a threaded member 98, said member being manually rotatable in response to rotative force applied to externally positioned wing sections 100. 'Ihe inner portion of the member 98 is threaded within an end casing 102, which casing is detachably secured to the end of the housing 72 by means of suitable screws 104.

Figure 1. The threaded member 98 is provided with an inwardly extending annular ange 106. Bearing against the outer side of this flange 106 and secured to the reduced outer end of the slidable member 92 is a thrust collar 108 and interposed between the other side of the flange 106 and a shoulder on the slidable member 98 is an anti-friction thrust bearing 110, Figure l. This thrust bearing also provides an abutment for the driving sleeve 66. The anti-friction bearing 68 of the sleeve 66 is secured in position by means of a clamping ring 112 on one side which is mounted upon the sleeve 66 and a clamping ring 114 which is secured against the .inner surface of the end casing 102 by means of suitable screws 116. A projection 118 on the end casing 102 is provided with suitable graduations, whereby the longitudinal displacement of the slidable member 92 may be accurately determined. By this micrometer adjustment the degree of stroke of the plungers 20 may be sensitively and positively controlled. Thisy adjustment for controlling the degree of plunger strokemay be made during the operation of the pumping mechanism as well as when said mechanism is at rest. It should be noted that the entire driving structure of my improved iluid propelling mechanism may be removed without disturbing the -main housing 72 by merely removing the screws 104. Said housing is also detachablyV secured to the stator 12 by means of suitable screws 120.

Referring again to the ngers 88 which rest upon the peripheral surface of the driving ring 84, it will be noted that'these fingers are Apivotally supported by means of suitable pins 122 which are mounted within the stator. These fingers 88 serve as an effective means for eliminating side thrust which would be imparted to the plungers in the event that said plungers bear directly against the driving ring, as shown in Figure 7. Any sidethrust of the driving ring 84 as it is swept along its orbit within thestator, is taken up by the pivotal fingers, and the only force transmitted to the plungers is one which acts in a substantially radial direction. If it is desirable to employ a construction in which the plungers bear directly against the driving ring, an arrangement, such as that shown in Figure 7, may be used. In this construction, .the inner extremities of the plungers may be provided with enlarged heads 124 which rest upon the'driving ring. In other words, my invention is not limited to any one particular plunger arrangement but is capable of numerous other modifications without departing from the spirit and scope thereof.

In the operation of the above described fluid propelling mechanism, the driving ring- 84 is rst adjusted by manually manipulating the threaded member 98 so as to obtain a plunger stroke, which corresponds to the fluid displacement requirements in the system with which the device is to be employed. This adjustment- 'may be made either'at the time the driving means 32 and the valve mechanism 30 are at rest, or whilesaid elements are being rotated. The rotation of said elements is occasioned in a suitable manner as by means of the driving gear 76. Fluid from the intake pipe line 54 passes into the end'chamber 40, between the balls of the anti-friction bearing 46 and then through the valve passageways 38 to' the valve port 36, as clearly shown by the directional arrows in Figure 5. 'I'his port 36 causes the fluid to be displaced into the chambersections 18a associated with the pistons which are experiencing an intake stroke. Simultaneously,

the valve port 36a is causing fluid under pressure from chamber sections 18a associated with the plungers which are experiencing a compressing stroke, to be displaced through the valve passageways 58 which communicate with the high pressure pipe line 62. In this manner fluid is introduced tothe plunger chambers through the valve port 36 and withdrawn from said chambers under increased pressures through the valve port 36a.

The'fluid propelling mechanism just described 4presents numerous advantages in the field of fluid propulsion or transmission, and has eliminated many of 'the disadvantages which have been experienced during the use of fluid pumps and the like of conventional design. It will be apparent from the foregoing description that my invention contemplates the provision of a propelling mechanism compactly arranged, and thereby presents a decided advantage over bulky cumbersome devices which have been available. In addition to compactness, my improved propelling device is very rigid in construction and capable of developing and withstanding very high uid pressures. The parts comprising the device are few in number and are so assembled as to facilitate access thereto. In fact, the entire driving mechanism may be removed without disturbing'any of the other elements, and the rotary valve mechanism may be removed without disturbing the driving mechanism and associated parts. Likewise, the pistons or plungers may be easily removed by merely unscrewing a plug mounted in the pump housing or stator. The anti-friction bearings employed for-mounting the driving mechanism, the mounting for the plunger actuating ring, and the friction reducing Abearing for taking up end thrust inthe rotary valve present a very practical arrangement whereby the smooth and uninterrupted operation of the rotatable parts is insured. The coupling between the rotary valve and the driving mechanism is' such as to positively prevent said valve from experiencing side thrust forces, and the pivotal fingers interposed between the actuating ring and plungers prevent said plungers from experiencing side thrusts. The fact that the rotary valve is supported solely by the bearing section of the stator and is not required to support other pump structures, enables said valve to maintain a true running fit in its bearing. The fact that the valve varies in 'diameter over its length, or; in other words, is of a tapered construction, positively prevents the leakage of fluid toward the smaller end thereof, and any fluid which passes from the opposite end is redirected immediately into operative association With the pump plungers.

Attention is also directed to the fact that by means of my improved shifting arrangement, the pistons may be shifted for the purpose of varying the stroke thereof without disturbing the timing of the valve. -This results from the fact that the entire coupling means is shifted radially with respect to the position of the pistons as distinguished fromother devices which have heretofore been employed wherein a rotary or other structure shifted in such a. manner as to affect the timing of the fluid valve.

My improved pumping mechanism is automatically adapted to be rendered functionally inoperative when connected within certain types of hydraulic circuits. Consider, for example, that the pump is connected Within a closed hydraulic circuit of the type set forth in my co-pending application, Serial No. 439,306, led March 27,

1930, and the movement of the uid outwardlyV remain at their outer positions, or at the position shown by the piston in Figure l. Any tendency for these pistons to move inwardly would be counteracted by the vacuum within the piston chamber 18a. The pistons connected with the high pressure pipe line 62 will also remain in their outer positions, because no uid is being delivered from the low pressure pipe line 54, which low pressure fluid under normal operating conditions serves to urge said pistons inwardly.

Thus it will be apparent that, by employing the plain type pistons 20, which are freely shiftable within their respective chambers and are not equipped with any mechanical devices which serve to urge said pistons inwardly, my pumping device is adapted to be rendered functionally inoperative in response to the arresting of the fluid flow within the

pipe lines

62 and 54, without requiring the stopping of the rotary pump driving mechanism. That is to say, the driving gear '76, which serves to impart rotation to the driving sleeve 66, Figure 1, may be continuously operated, although the functioning of the pump pistons 20 may be interrupted at any desired interval during said continuous operation. Immediately upon the reestablishment of the fluid flow within the

pipe lines

62 and 64, the pistons will again be automatically rendered functionally operative.

Obviously, my invention is not limited to the specic pumping arrangement shown in the drawings, but has a very broad application in the field of propelling devices. My invention is applicable to motors, fluid propelling devices, compressors, and various other mechanisms where a uid medium is used as a propelling instrumentality.

Attention is directed to applicants co-pending applications, Serial No. 430,866, filed of even date, and Serial No. 437,960, filed March 22, 1930. In application, Serial No. 430,866, the valve structure per se, as well as the combination thereof with a circuit arrangement, is disclosed and claimed, and in application, Serial No. 437,960, the adjustable driving mechanism per se is described and claimed.

Having thus described my invention, what I claim as new and desire to secureby Letters Patent is:

1. A plunger pump including a stationary cylinder block having a central pump chamber, a plurality of radially reciprocable plungers in said block, each of said plungers having an inner curved surface, rotary driving means for imparting movement to said plungers, and a pivoted member within said chamber interposed between the curved surface of each plunger and said driving means, the Aengagement of said pivoted member with said curved surfaces being limited to a local area of said curved surfaces whereby to eliminate substantially all side thrust during the movement of said plungers.

2. A plunger pump including a stationary cylinder block having a central pump chamber, a plurality of radially reciprocable plungers in said block, each of said plungers having an inner curved surface, rotary driving means for imparting movement to said plungers, and swingable members pivotally supported by said block, each of said swingable members being interposed between said rotary driving means and a companion plunger, the engagement between said swingable members and said plungers being limited to a local area of said curved surfaces whereby to eliminate substantially all side thrust during the movement of said plungers.

3. In combination, la plurality of pistons reciprocable within cylinders for receiving and discharging fluid, a tapered valve seat, a correspondingly tapered valve extending within said seat, cooperative ports in said tapered seat and valve for controlling the flow of fluid toward and away from said pistons during relative rotation of said valve and seat, and means for securing said tapered seat and valve against placement due to fluid pressure experienced within said cylinders and for enabling the complementary surfaces of said seat and valve to be spaced from each other a distance which is just suiiicient to insure the presence of --a fluid lm and thereby maintain the volumetric migration of fluid between said complementary surfaces negligible throughout an operating range of fluid pressures experienced within said cylinders.

4. In combination, a plurality of pistons reciprocable within`cylinders for receiving and discharging fluid, a tapered valve seat, a correspondingly tapered valve extending within said seat, cooperative ports in said tapered seat and valve for controlling the ow of fluid toward and away from said pistons during relative rotation of said valve and seat, means for securing said tapered seat and valve against relative axial displacement due to fluid pressure experienced within said cylinders' and for venabling the complementary surfaces of said seat and valve to be spaced from each other a distance which is just suilicient to insure the presence of a fluid film and thereby maintain the volumetric migration of fluid between saidv complementary surfaces negligible throughout an operating range of uid pressures experienced within said cylinders, and uid salvaging means associated with the larger extremity of said valve to receive fluid which moves toward said extremity.

5. In combination, a plurality of pistons reciprocable within cylinders for receiving and discharging iluid, a tapered valve seat, a correspondingly tapered valve extending within said seat, cooperative ports in said tapered seat and valve for controlling the ow of fluid toward and away from said pistons during relative rotation of said valve and seat, means seat and valve against relative axial displacement due to fluid pressure experienced within said cylinders and for enabling the complementary surfaces of said seat and valve to be spaced from each other a distance which is just sufcient to insurel the presence of a fluid film and thereby maintain the volumetric migration of fluid between said complementary surfaces negligible throughout an operating range of fluid pressures experienced within said cylinders, and rotary driving mechanism for causing relative rotation of the valve and seat, sa'd mechanism including la rotary driving member positioned in substantially axial alignment with'said valve.

6. In combination, a plurality of pistons reciprocable within cylinders for receiving and discharging uid, a tapered valve seat, a correspondrelative axial disfor securing said taperedl ingly tapered valve extending within said seat, cooperative ports in said tapered seat and valve for controlling the ow of fluid toward and away from said pistons during relative rotation of said valve and seat, and adjustable means for securing said tapered seat and valve against relative axial displacement due to 4fluid pressure experienced within said cylinders and for enabling the complementary surfaces of said seat and valve to be spaced from each other a distance which is just suflicient to insure-the presence of a fluid film and thereby maintain the volumetric migration of fluid between said complementary surfaces negligible throughout an operating range of iiuid pressures experienced within said cylinders, the adjustability of the securing means serving to control the degree ofspacing between the complementary surfaces of the seat and valve.

7. In combination, a plurality of pistons reciprocable within cylinders for receiving and discharging uid, a tapered valve seat, a correspondingly tapered valve extending within said seat, cooperative ports in said tapered seat and valve for controlling the flow of fluid toward and away from said pistons during relative rotation of said valve and seat, and a thrust bearing cooperating with the larger extremity of the valve for securing said valve against axial displacement due to fluid pressure experienced within said cylinders and for enabling the complementary surfaces of said seat and valve to be spaced from each other a distance which is just sumcient to insure the presence of a fluid lm and thereby maintain the volumetric migration of fluid between said complementary surfaces negligible throughoutan operating range of fluid pressures experienced within said cylinders.

8. In combination, a plurality of pistons reciprocable within cylinders for receiving and discharging fluid, a tapered valve seat, a correspondingly tapered valve extending within said seat, cooperative ports in said tapered seat andA valve for controlling the flow of fluid toward and away from said pistons during relative rotation of said valve and seat, a uid receiving chamber at one extremity of said valve, and means within said chamber for securing said tapered seat and valve against relative axial displacement due to fiuid pressure experienced within said cylinder and for enabling the complementary surfaces of said seat and valve to be spaced from each other a distance which is just'sucient to insure the presence of a'iuid film and thereby maintain the volumetric migration of fiuid between said complementary surfaces negligible throughout an operating range of fluid pressures experienced within said cylinders.

9. In combination, a plurality of pistons reciprocable within cylinders for receiving and discharging fluid, a tapered valve seat, a correspondingly tapered valve extending within said seat, cooperative ports in said tapered seat and valve for controlling the flow of fluid toward and away from said pistons during relative rotation of said valve and seat, and anti-friction bearing means for securing said tapered seat and valve against relative axial displacement due to fluid pressure experienced within said cylinders and for enabling the complementary surfaces of said seat and valve to be spaced from each other a distance which is just sufiicient to insure the pressure of a fluid film and thereby maintain the volumetric migration of uid between said Acomplementary surfaces negligible throughout an operating range of fluid pressures experienced within said cylinders.

10. In combination, a plurality of pistons reciprocable within a stationary cylinder block for receiving and discharging fluid, a tapered valve seat, a corresponding tapered rotary valve extending within said seat, cooperative ports in said tapered seat and valve for controlling the flow of fluid toward and away from said pistons during rotation of said valve, and means for securing said tapered seat and valve against relative axial displacement due to fluid pressure experienced within said cylinders and for enabling the complementary surfaces of said seat and valve to be spaced from each other a distance which is just suicient to insure the presence of a fiuid film and thereby maintain the volumetric migration of fluid between said complementary surfaces' negligible throughout an operating range of fluid pressures experienced within said cylinders.

ll. In combination, a plurality of pistons reciprocable within cylinders for receiving and discharging fluid, a tapered valve seat, a correspondingly tapered valve extending within said seat, cooperative ports in said tapered seat and valve for controlling the flow of fluid toward and away from said pistons during relative rotation of said valve and seat, said valve having fluid conducting passages extending longitudinally thereof for communication with said ports, said passages being small enough in cross section as compared with the cross sectional area of the valve to prevent said valve from experiencing lateral distortion as a resultof fluid pressure experienced within said passages, and means for securing said tapered seat and valve against relative axial displacement due to fluid pressure experienced Within said cylinders and for enabling the complementary surfaces of said seat and valve to be spaced from each'other a distance which is just sucient to insure the presence of a uid lm and thereby maintain the volumetric migration of uid between said complementary surfaces negligible throughout an operating range of Huid pressures experienced within said cylinders.

12. A propelling mechanism including a cylinder block, a plurality of radial pistons movable under fluid pressure within said block, a rotary driving mechanism operatively associated with said pistons,`said driving mechanism including a rotary member, a friction reducing bearing providing a support over substantially the entire extent of said rotary member, and an eccentric driving member eccentrically adjustable by transverse bodily movement, mounted within and rotatable as a unit with said rotary member, said eccentric driving member having one end projecting axially beyond said bearing and. arranged for driving cooperation with the extremities of said pistons, a substantial portion of said eccentric driving member toward its opposite end directly engaging, for lateral support, the portion of the rotary member enclosed by said bearing whereby to reduce the overhang of said end projection beyond said bearing.

13. A propelling mechanism including a cylinder block, a plurality of radial pistons movable under fluid pressure withinsaid block, a rotary driving mechanism operatively associated with said pistons, said driving mechanism including a rotary member, a friction reducing bearing providing a support over substantialy the entire extent of said rotary member, an eccentric driving driving mechanism and bearing structure in said member eccentrically adjustable by transverse bodily movement, mounted within and rotatable as a unit with said rotary member, said eccentric driving member having one end projecting axially beyond said bearing and arranged for driving cooperation with the extremities of said pistons, a substantial portion of said eccentric driving member toward its opposite end directly engaging, for lateral support, the portion of the rotary member enclosed by said bearing whereby to reduce the overhang -of said end projection beyond said bearing, and means shiftable within said rotary member for varying the eccentricity of said eccentric driving member.

14. A propelling mechanism including a cylinder block, a plurality of radial pistons movable under uid pressure within said block, a bearing, a rotary member mounted within said bearing and having a transverse guideway,'an eccentric driving member eccentrically adjustable by transverse bodily movement within said transverse guideway and rotatable as a unit with said rotary member, said eccentric driving member having one end projecting axially beyond said bearing and arranged for driving cooperation with the extremities of said pistons, a substantial portion of said eccentric driving member toward its opposite end directly engaging, for lateral support, the portion of the rotary member enclosed by said bearing whereby to reduce the overhang of said end projection beyond said bearing, and means for controlling the shifting of the eccentric driving member within said rotary member.

15. A propelling mechanism including a cylinder block, a plurality of radial pistons movable under fluid pressure within said block, a bearing, a rotary member mounted within said bearing and having a transverse guiding portion, an eccentric driving member having its axis parallel with the axis of the rotary member and shiftably mounted within said transverse guiding portion, said eccentric driving member having one end projecting axially beyond said bearing and arranged for driving cooperation with the extremities of said pistons, a substantial portion of said eccentric driving member toward its opposite end directly engaging, for lateral support, the portion of the rotary member enclosed by said bearing whereby to reduce the overhang of said end projection beyond said bearing, and means for shifting the eccentric driving member within said rotary member in such a marmer that the parallelism lof the axes of said eccentric and rotary members is maintained.

16. A propelling mechanism including a cylinder support, a plurality of pistons radially reciprocable within said support, passageways for directing uid toward and away from said cylinders, valve means carried by said cylinder support for controlling the flow of fluid in said passageways, a housing constructed and arranged to detachably receive said cylinder support, a bearing structure carried as a unit by said housing, and an eccentric rotary driving mechanism extending within and secured as a unit against lateral displacement by said bearing structure, an end portion of said rotary driving mechanism adapted for cooperative association with said pistons when the cylinder support is coupled with said housing, a portion at least of said bearing'structure being positioned in the vici ty of and adapted to lend support to said end portion, said cylinder support being detachable from the housing without disturbing the unit assemblage of the housing.

17. A propelling mechanism including a cylinder support, a plurality of rocable within said support, passageways recting fluid toward and away from said ders, valve means carrie for controlling the ways, a housingconstructed and arranged tachably receive sai structure including axia bearing elements carried a ing, and an eccentric rotary pistons radially recipfor dicylind by said cylinder support f fluid in said passageto ded cylinder support, a bearing lly spaced antifriction s a unit by said housdriving mechanism extending within and secured asa unit against lateral displacement by an end portion of said rot adapted for cooperative association tons when the cylinder support is couple said housing, said Cy able from the housing without di assemblage of the drivingmechanism and bearing structure in said housing.

18. A propelling' inder support, a

mechanism including said bearing structure, ary driving mechanism with said pisd. with linder support being detachsturbing the unit a cylplurality of pistons radially reciprocable within said support, valve means carried by said ,suppor fluid toward and away ing constructed and arrange ceive said cylinder driving mechanism carried ing and operatively associa when the cylinder housing, and pivoted ngers carrie der support and ada said pistons and sa nism, said cylinde blage of the driving support, an eccentric support l Supp mechanism in said hou t for controlling the flow of from said pistons, a housd to detachably rerotary as a unit by said housted with said pistons is mounted on said d by said cylinpted to be positioned between id eccentric driving mechaort being detachable from the housing without disturbing the assemsing.

19. A propelling mechanism including a cylinder support, a plurality under fluid pressure within said support,

tary driving the entire extent of ing for said bearing mechanism oper of radial pistons movable atively associated said driving mechanism ina friction reducing over substantially said rotary member, a housably carry said cylinder support, and an tric driving member eccentrically adjustable Ywithin and projecting axially bearing *whereby rotatab said eccentric driving member end projection beyond said bearing, said der support and parts tachable as a unit without affecting which is adapted to detacheccenle with said rotary member, having one end beyond said bearing and arooperation with the extrema substantial portion of said ber toward its opposite end lateral support, the porr enclosed by said to reduce the overhang of saidv cylincarried thereby being dewith respect to said housing the assemblage of the rotary driving mechanism.

20. A propelling mec der support, a plurality of radial pistons movable under fluid pressure within said support, a

bearing structure including axially spaced beara unit and adapted tachably receive said cylinder support, a

member mounted an eccentric mounted within sai within and secured as ldriving d transverse guiding p ing elements, a housing adapted to carry said bearing structure as to derotary a unit acement by said bearing, said g a transverse guiding por-l member shiftably a portion of said shiftable eccentric member toward one end extending within the connues of said bearing so as to receive lateral support therefrom, the opposite end projecting axially beyond said bearing structure, vand means carried by said housing for controlling the shifting of the eccentric driving member within said rotary member, said cylinder support and parts supported thereby being detachable as a unit from said housing without disturbing the assembled relationship of the driving mechanism and bearing structure within said housing.

21. A propelling mechanism including a cylinder block having a central chamber, a plurality of radially reciprocable pistons in said block, eat-h of said pistons having an inner curved sur face, rotary driving means operatively associated with the inner extremities of said pistons, and pivoted fingers within said chamber and interposed between said driving means and said pistons, the engagement between said ngers and the curved surfaces of said pistons being limited to a local area of said curved surf-aces whereby to eliminate substantially all side thrusts during the movement of said pistons.

22. A propelling mechanism including a cylinder block, a plurality of radial pistons movable under fluid pressure within said block, a rotary driving mechanism operatively associated with said pistons, said driving mechanism including a rotary member, a friction reducing bearing providing a support .over substantially the entire extent of said rotary member, an eccentric driving member eccentrically adjustable by transverse bodily movement, mounted within and rotatable as a unit with said rotary member, said eccentric driving member having one end projecting axially beyond said bearing and arranged for driving cooperation with the extremities of said pistons, a substantial portion of said eccentric driving member toward its opposite end directly engaging, for lateral support, the portion of the rotary member' enclosed by said bearing whereby to reduce the overhang of said end projection beyond said bearing, and means for controlling the eccentricity of said driving member including micrometer screw means for accurately governing the degree of eccentricity.

23. A propelling mechanism including a cylinder block, a' plurality of radial pistons movable under fluid pressure within said block, a bearing, a rotary member mounted within said bearing and having a transverse guideway, an eccentric driving member eccentrically adjustable by transverse bodily movement within said transverse guideway and rotatable as a unit with said rotary member, said eccentric driving member having one end `projecting axially beyond said bearing and arranged for driving cooperation with the extremities of said pistons, a substantial portion of said eccentric driving member toward its opposite end directly engaging, for lateral support, the portion of the rotary member enclosed by said bearing whereby to reduce the overhang of said end projection beyond said bearing, and means for controlling the shifting of the eccentric driving member within said rotary member, .including micrometer screw means for accurately governing 4the degree of shifting of said eccentric driving member.

ERNEST J. SVENSON.