US3272139A

US3272139A - Pumps

Info

Publication number: US3272139A
Application number: US439492A
Authority: US
Inventors: Oscar E Rosaen
Original assignee: Individual
Current assignee: Individual
Priority date: 1964-12-29
Filing date: 1964-12-29
Publication date: 1966-09-13
Anticipated expiration: 1983-09-13

Description

Sept. 13, 1966 o. E. ROSAEN y3,272,139

PUMPS Filed Dec. 29, 1964 8 Sheets-Sheet 1 ATTORNEYS Sept 13, 1966 o. E, ROSAEN 3,272,139

PUMPS Filed Dec. 29, 1964 8 Sheets-Sheet 2 9 I NVE NTOR OSCAR E. ROSAEN BY QAM ATTORNEYS Sept. 13, 1966 o. E. Ros/AEN 3,272,139

PUMPS Filed Dec, 29, 1964 8 Sheets-Sheet 3 Fl G. as

\\ if F: G. 5.

77 al 7@ INVENTOR. 7, OSCAR E. RosAEN 68 BY f l $7/ Mc# H 5a ATTORNEYS Sept, 13, 1966 o. E. ROSAEN 3,272,139

PUMRS Filed Dec. 29, 1964 8 Sheets-Sheet 4 INVENTOR. OSCAR E. RosAEN ATTORNEYS Sept- 13, 1966 o. E. RosAl-:N 3,272,139

ATTORNEYS O. E. ROSAEN Sept. 13, 1966 PUMPS 8 Sheets-Sheet 6 Filed Dec. 29, 1964 sept 13, 1966 o. E. RosAEN 3,272,139

PUMPS Filed DeC. 29, 1964 B Sheets-Sheet '7 INVENToR OSCAR E. RosAEN l zo a:

ATTORNEYS Sept 13, 1966 o. E. RosAr-:N 3,272,139

PUMPS Filed Dec. 29, 1964 8 Sheets-Sheet 8 mvENToR FIG. I8 oscAR E. RosAEN BY aV// ATTORNEYS United States Patent O 3,272,139 PUMPS Oscar IE. Rosaen, Grosse Pointe, Mich. (1776 E. Nine Mile Road, Hazel Park, Mich.) Filed Dec. 29, 1964, Ser. No. 439,492 11 Claims. (Cl. 103 120) This application is a continuation-impart of patent application Serial No. 296,657, filed July 22, 1963, now abandoned.

This invention relates to vane type pumps and more particularly to a new concept in automatically controlled varia-ble delivery vane pumps.

In vane type pumps, conventional elements include a housing having a chamber for a rotor With sliding vanes, the vanes being urged into contact with a peripheral cam and sliding radially in and out with respect to the rotor as the cam surface varies in spacing from the rotor, producing in the spaces between vanes a pressure differential, so that fluid will be discharged under pressure through an appropriately positioned outlet and sucked in through an appropriately positioned inlet from a fiuid source. Without more, such a pump operating at constant speed will deliver a substantially constant volume of fluid. However, as loads and demands in the system using the delivered iiuid vary, so will the pressure of fluid vary, producing various undesirable results.

The concept of shifting the cam or a portion thereof with respect to the rotor axis as desired to vary the delivery under changing conditions is of course not new, but heretofore the problems engendered in providing a practical system have been great, and have led to enormously complex and resultingly expensive mechanisms. Moreover, no such pumps heretofore, to my knowledge, have been free from other problems caused by using a shiftable cam or rotor, as for example, the problems of unbalanced internal pressures, unpredictable wear characteristics, undesirable hunting, control difficulties, and difficulty in controlling and stabilizing heavy masses.

The present pump solves the aforesaid problem by retaining the rotor axis and the greater portion of the cam surfaces stationary at all times. Variable delivery is produced by merely shifting a small cam portion radially with respect to the rotor, which can be done with a simple actuating mechanism, and providing a unique hinged ramp connecting the stationary and shiftable cam portions. Such a device, combined with internal pressure balancing means, is more easily and cheaply manufactured, adjusted, and maintained than pumps heretofore devised.

For a complete understanding of my invention, reference may be had to the accompanying drawings illustrating preferred embodiments of the invention in which like reference characters refer to like parts throughout the several views, and in which FIG. 1 is a longitudinal cross-sectional view of a pump embodying the present invention, taken on the line 1 1 of FIG. 2.

FIG. 2 is a cross sectional view taken substantially on the line 2 2 of FIG. 1.

FIG. 3 is a cross sectional view taken substantially on the line 3 3 of FIG. 2.

FIG. 4 is a cross-sectional view taken substantially on the line 4 4 of FIG. 1.

FIG. 5 is a fragmentary cross-sectional view illustrating a portion of the pump rotor and adjustable cam portion as will be described.

FIG. 6 is a plan view of a cheek plate as seen from the line 6 6 of FIG. 2.

FIG. 7 is a view of the opposite face of the cheek plate of FIG. 6.

FIG. 8 is a plan view of a cheek plate as seen from the line 8 8 of FIG. 2.

FIG. 9 is a view of the opposite face of the cheek plate of FIG. 8.

FIG. 10 is fragmentary cross-sectional view taken substantially on the line l0-10 of FIG. l.

FIG. 11 is a fragmentary cross-sectional View taken substantially on the line 11 11 of FIG. 5.

FIG. l2 is a fragmentary view directed radially outward viewing the ramp and cam surfaces of the invention,

FIG. 13 is a cross-sectional view of another preferred modification of the pump.

FIG. 14 is a cross-sectional view taken substantially on the line 14-14 of FIG. 13.

FIG. 15 is a cross-sectional view taken substantially on the line 15-15 of FIG. 14.

FIG. 16 is a cross-sectional view taken substantially on the line 16 16 of FIG. 14.

FIG. 17 is a cross-sectional view taken substantially on the line `17 17 on FIG. 13.

FIG. 18 is a perspective view of a cam ring member embodied in the modification of FIGS. 13-17.

FIG. 19 is a perspective view of a movable cam element embodied in the modification of FIGS. 13-17.

Description As seen in FIGS. 1-12 the preferred pump comprises a housing 10 having a mounting flange 11, a large central cylindrical chamber 12, and a stepped shaft bore 13 (FIG. 2).

Exterior bosses

14 and 15 have, resepctively,

inlet and

outlet passages

16 and 17 and are provided with

pipe fittings

18 and 18A secured by any means such as screws 19. The fitting 18 is` adapted for connection to a Suitable fluid source (not shown), and the fitting 18A is adapted for connection to a pressure fluid user (not shown).

As seen in FIGS. 2 and 4, the open end of the chamber 12 is closed by an end cap 20 secured to the housing by screws 21 or the like. As shown in FIG. 1, on the side of the housing 10 is a control housing 23 and closing a rectangular bore 22 and secured to the housing 10 by screws 24, containing control elements which will subsequently be described in more detail.

Inside the chamber 12 and fitting peripherally therewith are

cheek plates

25 and 26 disposed on opposite sides of a cam ring 27. These rnay be held together by any means such as screws 28. The

cheek plates

25 and 26 are illustrated in detail in FIGS 2, 4, and 6-9.

The cam ring 27 has an internal substantially annular cam surface 29 disposed substantially concentric with a rotor 30 which is splined as at 30A to a driving shaft 31. The rotor 3f? is provided with a plurality of equally spaced transverse slots 30B open to the periphery of the rotor and slidably holding vanes 32, the outer ends of which engage the cam surface 29 as the rotor 30 rotates in a counterclockwise direction as seen in FIG. 1.

The cam ring 27 has inlet and outlet passages respectively 33 and 34 open at their outer ends to the respective inlet and

outlet passages

16 and 17 in the housing 10, and open at their inner ends to the space bounded by the cam surface 29 and lthe inner sides of the

cheek plates

25 and 26 within which the rotor moves.

The inner ends of the vane slots 30B in the rotor end in transverse bores 35 which, as the rotor 31) turns, successively lregister with

elongated ports

36, 36A, 37 and 37A provided in the inner sides of the

cheek plates

25 and 26. The intake port 16 has portions 16A as seen in FIG. 2 extending over the

cheek plates

25 and 26 to communicate with inwardly extending passages 38 open at their inner ends to the ports 36 as shown in FIG. 2. An annular recess 39 and radially extending

passages

40 and 40A provided in the end cap 20 openly communicate the elongated port 36 with the diametrically disposed port 36A via

holes

41 and 41A extending through the cheek plate 26.

Elongated ports 42 in the

cheek plates

25 and 26 are disposed diametrically opposed the inlet 33, opening to an area between the rotor 30 and the cam ring 27 approximately equal in arcuate extent to the inlet 33, and connected with passage 40A via a hole 43 in the cheek plate 26.

As the rotor turns, suction is produced in the area of the space Ibetween rotor 30 and cam ring 27, in which are disposed the outer ends of the vanes 32, and is transmitted to the passage 33, and substantially atmospheric pressure is communicated by means of the foregoing pas- -sages 38 to the bores 35 beneath the inner ends of the vanes 32 successively moving through the intake area and through the diametrically positioned suction area adjacent the ports 42. Thus the vanes 32 passing through suction areas are urged outwardly by unequal pressure across their ends. Also, it will be apparent that the opposite sides of the rotor 30 are pressure balanced.

The cam ring su-rface 29 has a gap therein extending from a transverse line X near the leading edge of the inlet passage 33 to a transverse line Y at the leading edge of the outlet passage 34 furthest removed from the inlet passage 33. A slidable cam member 50 extends linto a portion of the gap X-Y and carries at its leading edge in a socket 51 the trailing end of a ramp member 52. The leading end of the ramp member 52 has a socket 53 carrying the ball end 54 of a plunger 55, which is spring loaded by a spring 55A to urge the ramp mem-ber 52 annularly toward the cam member 50 at all times. The ramp member 52 traverses that area of the gap X-Y adjacent the opening from the outlet passage 34. The cam member 50 has a cam surface 56, the leading end of which is at all times tangent to the trailing end of the ramp member 52 due to its conformation and engagement in the socket r51. The leading end of the ramp member 52 is likewise approximately tangent at all times to the trailing end of the cam surface 29 at line Y. The cam member 50 is slidable radially with respect to the rotor axis and, when adjusted toward and away from the rotor as will be explained, varies the space between the cam surface 56 and the periphery of the rotor 30. The ramp member 52, being in effect hinged at the leading edge to the cam ring and at the trailing edge to the cam member 50, provides a slope over which the outer ends of the vanes 32 slide in transferring from the cam surface 29 to the cam surface 56.

As seen in FIG. 12, which is a radially outward directed view, the leading end of the ramp membe-r 52 has a tongue 52A fitting -between fork ends 27A of the cam ring such that, when the ramp is moved to the dot-dash position, there will yet be adjacent surfaces of the cam and ramp for the vanes to slide over in making the transfer from cam to ramp.

With the cam member 50 in the position shown in FIG. l, it will be seen that in the transitional area the vanes 32 will be moved into their slots so that the volume of the space `between successive vanes 32 decreases. Fluid which has been ca-rried by the vanes will be expelled laterally around the ramp member 52 and out the outlet passage 34 under pressure. The

cheek plates

25 and 26 have recesses 60 which are open to the outlet passages 34 and communicate, via

passages

61 and 62, with the elongated slots 37 in the

cheek plates

25 and 26, which slots are successively opened to the inner ends 35 of the vane slots.

The cheek plate has on its outer side an annular recess 63, which as seen in FIG. 4, is openly connected with the recess 60 by a passage 64, with the recess 37A Iby a passage 65, and with a passage 66 which opens to elongated ports 67 disposed diametrically opposite to the outlet 34. Pressure uid is thus communicated by means of the foregoing passages to the bores 35 beneath the vanes 32 successively moving through the intake area and to the bores 35 beneath the vanes 32 successively moving through the diametrically positioned pressure area adjacent the ports 67. Thus the inner and outer ends of the vanes 32 passing through pressure areas are pressurebalanced as are the opposite sides of the rotor 30.

It will be seen that the volume of fluid delivered through the outlet 34 will depend on the spacing between the cam member -surface 56 and the periphery of the rotor. This spacing is automatically varied according to the pressure at the outlet 34 by mechanism, hereafter described, disposed in the control housing 23 and connected with the cam member 50 as see in FIGS. 1, 5, 10 and 11.

The housing 23 has a cylindrical chamber 70 containing a large piston 71 which is carried on the outer end of the cam member 50, which cam member 50 is rectangular in cross section laterally with respect to its axis of movement. The housing 10 has the rectangular bore 22 previously noted, and the cam ring 27 has a rectangular bore 72 in registry therewith. As seen in FIGS. 1, 5 and 11, one side of the bore 72 has a recess 72A in which are disposed a series of rollers 73 on which the cam member 50 will ride as it is moved toward and away from the rotor 30. A leaf spring element 74 is disposed at one end of the recess 72A and as the rollers 73 roll with the cam member 50, the spring element 74 compresses and expands. A spring loaded sealing vane 68 on the opposite -side of the member 50 from the roller 73 engages the side of the bore 72 on the pressure side thereof.

The cam member 50 is provided with a bore 75 in which slides a control valve 76 as seen in FIGS. 1 and 10. A pin 77 is slidably carried in a bore 78 and is biased against the valve 76 by a spring 79. The valve 76 is in turn biased against a pin 80 extending through the piston 71 by a spring 81. The pin 80 engages an abutment 82 which is biased toward the piston 71 by a spring 83 cornpressed between the abutment 82 and a seat 84 which can be adjusted axially in a bore 85 by means of a screw 86 having a lock nut 87. Making the pin 77, valve 76, pin 80, and abutment 82 separate eliminates the need for exact alignment of the parts and their consequently required close tolerance machining.

Pressure fluid is introduced to the inner end of the pin 77 from a passage 90 provided in the member 50.

Passages

91 and 92 in the member 50 carry pressure Huid to an annular groove 93 encircling the valve 76, thence to an annular groove 94 in the valve 76 and through passages 95 and 96 to opposite ends of the valve 76 and lfrom the outer end thereof to the outer side of the piston 71. The piston 71 having a considerably greater effective area than the inner end of the cam member 50 exposed to fluid pressure, the normal position of the member 50, as shown in FIG. 1, is such that the pump is producing maximum fluid delivery.

When demand decreases, such as when a valve in the fluid user system downstream closes, the discharge pressure rises, and the rise in pressure is sensed at the inner end of the pin 77 to move the valve 76 outward against the compression of the spring 83. The valve groove 94 will move out of registry with the groove 93, shutting off pressure to the outer side of the piston 71 and opening the outer side of the piston, through a passage and an annular groove 101 in the member 50, to an annular groove 102 which will have opened to the groove 101. Pressure is thus exhausted through another annular groove 103 in the member 50 and passages 104 to the inner side of the piston 71, which is openly communicated with the inlet passage 16 by means of a passage 105.

With pressure removed from the piston 71, the pressure on the inner end of the cam member 50 moves same radially away from the rotor 30. As seen in FIG. 5, the slope of the ram 52 decreases, the vanes 32 slide inward a lesser degree, and delivery volume decreases. The

adjustment of compression of the spring 83 will determine at what pressure the control device regulates.

Springs 110 compressed between the outer side of the chamber 7l) and the piston 71 insure that when the pump is first started the cam member 50 will be at its innermost position, s-o the pump will initially be operating at maximum delivery.

As seen in FIG. 5, the vanes 32 are disposed at an angle to rotor radii such that when they move off of the cam surface 56, regardless of its position, they will always be parallel to the axis of member 50 motion, and thus for different positions, the vanes will always move into the suction area at the same time. When the vanes 32 leave the cam surface 56, they will readily extend to engage the cam ring surface 29 by the inuence of centrifugal forces as well as unbalanced pressure previously described.

Leakage preventive means are provided in the present pump by venting the drive shaft bore space 115 in the housing 10 to suction pressure by means of a passage 116 open to the passage 33. A seal assembly 117 is provided for the shaft 31 inwardly of the shaft bearing assembly 118 as seen in FIG. 2.

The pressurized annular recess 63 in the cheek plate 25 is closed by means of an annular ring 119 carried therein and urged into contact with the inner end of the chamber 12 'by means of two radially spaced sealing O-rings 129 and 120A in the recess 63, which O-rings are compressed on assembly of the cheek plates and cam ring when the end cap 2t) is secured in place.

The -shaft 31 is rotatably supported in the

cheek plates

25 and 26 by means of bushings 121. Other incidental details of construction will be apparent to one skilled in the art.

In the modication of FIGS. 13-19, the pump comprises a housing 210 having a mounting flange 211, a large central cylindrical chamber 212, a shaft bore 213, an intake 216, a primary outlet 217, and a secondary outlet 218.

The open end of the chamber 212 is closed by an end cap 220 secured to the housing 210 by screws 221 or the like. On the side of the housing 210, and closing a side chamber 222, is a control housing 223 secured to the housing 210 by screws 224.

Inside the chamber 212, and supported by the housing 21d, are

cheek plates

225 and 226 sandwiching between them a cam ring 227, shown in detail in FIG. 18. The cheek plates and cam ring may be secured against relative displacement by a screw 228 or the like.

The cam ring 227 has an internal substantially annular cam surface 229 disposed concentrically with respect to a rotor 230 which is splined as at 230A to a driving shaft 231. The rotor 230 is provided with a plurality of equally spaced transverse slots 230B open to the periphery of the rotor and slidably holding vanes 232, the outer ends of which engage the cam surface 229 as the rotor 236 rotates in a counterclockwise direction as seen in FIG. 13.

The cam ring 227 has inlet and

outlet passages

233 and 234 respectively open at their outer ends to the respective inlet and

outlet passages

216 and 217 in the housing 211i), and open at their inner ends to the space bounded by the cam surface 229 and the inne-r sides of the

cheek plates

225 and 226 within which the rotor moves.

The inner ends of the Vane slots 230B end in transverse bores 235 which, as th-e rotor turns, successively register with

ports

236, 236A, 237 and 237A provided in the inner side-s of the

cheek plates

225 and 226.

The housing chamber 212 has an enlargement 212A (FIGS. 14 and 16) at its inner end to communicate the intake 216 with passages 238 in the cheek plate 225 open at the inner ends to the

ports

236 and 236A in the cheek plate 225. The end cap 220 has a vbroad groove 220A running across its inner face (see FIGS. 14 and l5) to communicate the intake 216 with the

ports

236 and 236A in the cheek plate 226. Thus, as the-rotor turns, the inner ends of the vanes 232 will be exposed to intake suction whenever the bores 235 register with the

ports

236 and 236A.

The cam ring outlet passage 234 communicates with a recess 241B (FIGS. 13 and 18) which opens to ports 241 in cheek plates 225 and 226 (FIGS. l5 and 16) respectively. A passage 241A communicates port 241 with the port 237 (FIG. 16) and a port 241B communicates port 241 with an annular recess 243 (FIG. 14) provided at the inner end of the chamber 212, into which lits a stepped portion 225A of the cheek plate 225. Inner and outer O-rings 244 seal off the recess 243 from the inlet connected enlargement 212A. The port 237A in cheek plate 225 is connected via a passage 244 with a recess 243 as is a groove 245 in the cheek plate 225 provided diametrically opposite the port 241. As the rotor turns, the inner ends of the vanes 232 will be exposed to discharge pressure when ever the bores 235 register with the

ports

237 and 237A and arcuate grooves 247 and 247A connected therewith. The cheek plate 226 also has

simi lar ports

237 and 237A, grooves 247 and 247A, and groove 245 so that opposite faces and opposite sides of the rotor are pressure balanced.

The cam ring surface 229 has a gap therein extending from a transverse line X near the leading edge of the intake passage 233 (FIGS. 13 and 18) to a transverse line Y at the leading edge of the outlet passage 234. A slidable .cam member 250 extends into a portion of the gap X-Y and carries at its leading edge in a socket 251 the trailing end of 252C of a ramp member 252 (FIGS. 13 and 19). The leading end of the ramp member 252 has a spherical socket 253 carrying the ball end 254 of a plunger 255 carried in a bore 255B in the ycam ring 227 and spring loaded by a spring 255A to urge the ramp member 252 toward the slidable cam member 250 at all times. The ramp member 252 traverses that area of the Igap X-Y adjacent the opening from the outlet passage 234. The cam member 250 has a cam surface 256, the leading end of which is at all times tangent to the trailing end of the ramp member 252.

The leading end of a cam surface 252A of the ramp member 252 is approximately tangent at all times to the trailing end of the cam ring surface 229 at line Y. The cam member 250 is slidable radially with respect to the rotor axis and, when adjusted toward and away from the rotor 230 it varies the space between the cam surface 256 and the periphery of the rotor 230. The ramp member 252, being in effect hinged at the leading edge to the cam ring 227 and at the trailing edge to 4the cam member 250, provides a slope over which the outer ends of the vanes 232 slide in transferring from the cam surface 229 to the cam surface 256.

With the cam member 250 in the position of FIG. 13 it will be seen lthat in the transitional area the vanes 232 will be moved into their slots so that the volume of the space between successive vanes 232 decreases. Fluid which has been carried by the vanes will be expelled through the holes 252B in the ramp member 252 and out the outlet passage 234 under pressure.

As was described for the modification of FIGS. 1-12, the inner and outer ends of the vanes 232 lof the FIGS. 13-19 modification are pressure balanced in similar fashion as they move through the pumping cycle.

It will be seen that lthe volume of fluid delivered through the outlet 234 will depend on the spacing between the cam member surface 256 and the periphery of the rotor 230. This spacing is automatically varied according to the pressure at the outlet 234 by the mechanism in the control housing 223 and connected with the cam member 250 as seen in FIG. 13.

As shown in FIGS. 13 and 17, the housing 223 has a cylindrical chamber 270 containing a large piston 271 which is carried on the outer end of the cam member 250, which cam member 250 is rectangular in cross section laterally with respect to its axis of movement. The housing 210 has the rectangular chamber 222 previously noted, and the cam ring 227 has a gap 272 substantially in registry therewith. As seen in FIGS. 13 and 18, one side of the gap 272 has a recess 272A in which are disposed a series of rollers 273 on which the cam member 250 will ride as it is moved toward and away from the rotor 230. A slide plunger element 274 is disposed behind the rollers 273 and urged toward same by pressure in ports 302, so that as the rollers 273 roll with the cam member 250, the plunger element 274 will give under pressure. A spring loaded sealing vane 268 lon the opposite side of the member 250 from the rollers 273 engages the side thereof.

The cam member 250 is provided with a bore 275 in which slides a control valve 276 as seen in FIG. 13. A pin 277 is slidably carried in a bore 278 and is biased against the valve 276 by pressure introduced through a passage 279 in the lcam member 250. The valve 276 is in turn biased against a pin 280 extending through the piston 271. The pin 280 engages an abutment 282 which is biased toward the piston 271 by a spring 283 compressed between the abutment 282 and a seat 284 which can be adjusted axially in a bore 285 by means of a screw having a lock nut 287. Making the pin 277, valve 276, pin 280, and abutment 282 separate eliminates the need for exact alignment of the parts and their consequently required close tolerance machining.

A passage 291 in the member 250 carries pressure iluid to an annular groove 293 encircling the valve 276. As pressure on the inner end of the member 250 tends to move it outwardly, the groove 293 will open a port 294 in the valve 276, admitting pressure through an axial passage 295 and out ports 296, through a central hole 297 in the piston 271 to the recess 270 on the outer side of the piston 271. The piston 271 having a greater effective area than the inner end of the cam member 250 exposed to fluid pressure, the member 250 will tend to assume its normal position as shown in FIG. 13, such that the pump is producing maximum iluid delivery.

When demand on the pump decreases, such as when a valve in the fluid user system downstream closes, the discharge pressure rises and is sensed at the inner end of the pin 277 to move the valve 276 outward against the compression of `the spring 283. The valve ports 294 will move out of registry with the groove 293, shutting off pressure to the outer side of the piston 271 and opening the outer side of the piston through an annular groove 301 in the valve 276 to the ports 302 open to the inner side of the piston 271. This pressure is then exhausted through a passage 305 to the inlet passage 216.

With pressure removed from the piston 271, the pressure on the inner end of the cam member 250 moves same radially away from the rotor 230. The slope of the ramp 252 then decreases, the vanes 232 slide inward a lesser degree, and delivery volume decreases. The adjustment of compression of the spring 283 will determine at what pressure :the control device regulates.

As seen in FIG. 13 the vanes 232 are disposed at an angle to the rotor radii such that when they move oil of the cam surface 256, regardless of its position, they will always be parallel to the axis of member 250 motion, and thus for different positions, the vane will always move into the suction area at the same time. When the vanes 232 leave the cam surface 256, they will readily extend to engage the cam ring surface 229 by the iniiuence of centrifugal forces.

It will be noted that the cam member 250 has a mass whose center is offset from the radial line of thrust toward the rotor 230. In order to compensate for this imbalance, which increases with increased pressure on the member 250, a pair of small pistons 150 (FIGS. 13 and 17) are carried in centrally offset recesses 151 provided in the large piston 271 and supplied with pressure fluid through passages 152 extending -through the member 250. The pist-ons will exert a force on the wall of the housing recess 270 counteracting imbalanced forces of the member 250 in proportion to the determinative fluid pressure lof the pump.

The cam ring 227 is provided with a recess 310, open to the intake connected enlargement 212A of the pump chamber 212 through a slot 311 in the cheek plate 225 (FIGS. 13, 14, 16 and 18), and open to the space between the rotor 230 and the cam surface 229 through ports 312. Ports 313, open to the space between the rotor 230 and the surface 229, connect with a recess 314 open to the secondary outlet 218 (FIG. 13) which is adapted for connection to the uid reservoir (not shown) from which the pump draws its fluid supply. When the pump is idling at little or no delivery, fluid normally would merely circulate around in the pump and become overheated, but in the present arrangement a small volume of fluid will be pumped in through recess 310 and ports 312, and be expelled out ports 313, recess 314 and secondary outlet 218 to reduce the chance of overheating.

It will be seen that the present construction provides a new, reliable, and relatively simplied means for producing variable delivery vane-type fluid pumps by retaining 4the rotor axis and the major portion of the cam ring in xed relative position and only utilizing a small variable cam portion, the vanes sliding from one to the other on a variable slope ramp. The present pump still has means to retain the pressure-balanced features so essential in vane-type pumps and yet has an infinite variation, within limits, of delivery relative to demand and discharge pressures. Not only are the vanes fully balanced, but the rotor itself is not subjected to irregular and unbalanced forces as it is in many pumps. Moreover, the large area of the control piston relative to the eieetive area of the opposing adjustable cam member ensures positive surge free automatic control over delivery volume. The number of movable elements and adjustments are kept to a minimum, and the forces necessary to produce effective operation are not high due to the relatively low masses of the movable elements.

Although I have described and illustrated only two preferred embodiments of the invention, it will be apparent to one skilled in the art to which the invention pertains that various changes and modifications may be made therein without departing from the spirit of the invention or the scope of the appended claims.

I claim:

1. A variable delivery pump comprising (a) a casing having a pumping chamber,

(b) a rotor in said chamber and having angularly spaced slidable vanes carried by said rotor,

(c) cam means contacting and guiding said vanes for sliding operation as said rotor turns, said cam means having a fixed portion and a movable portion, and

(d) means displacing said movable portion toward and away from said rotor,

(e) said movable cam `portion having a laterally extending semi-cylindrical socket at one end,

(f) said cam means `includes a ramp section hinged on an axis extending parallel to said rotor axis,

(g) said ramp section having a laterally extending semi-cylindrical end shaped complementary to and engaged in said socket for hinging movement therein, and

(h) means resiliently urging said ramp semi-cylindri- -cal end into said semi-cylindrical socket at all times.

2. A variable delivery pump comprising (a) a casing having a pumping chamber,

(b) a rotor in said chamber and having angularly spaced slidable vanes carried by said rot-or,

(c) cam means contacting and guiding said vanes for sliding operation as said rotor turns, said cam means having a xed portion and a movable portion,

(d) means displacing said movable portion toward and away from said rotor,

(e) means responsive to pump pressures to actuate said means displacing said movable portions,

(f) said displacing means comprising a piston operably connected with said movable cam portion, and

(g) said pressure responsive means comprising valve means carried by said movable cam portion and variably directing pump delivery pressure to one end of said piston.

3. A variable delivery pump comprising (a) a casing having a pumping chamber,

(c) cam means contacting and guiding said vanes for sliding operation as said rotor turns, sa-id cam means having a xed portion and a movable portion,

(d) means displacing said movable portion toward and away from said rotor,

(e) said vanes being kinclined with respect to radii of the rotor at an angle such as to be parallel with the axial motion of the movable cam portion at 'the moment said vanes cease guiding contact with the movable cam portion during rotor operation.

4. A variable delivery pump comprising (a) a casing having a pumping chamber,

(c) cam means contacting and guiding said vanesl for sliding operation as said rotor turns, said cam means having a fixed lportion and a movable portion,

(d) means displacing said movable portion toward and away from said rotor,

(e) said displacing means comprising a pressure actuated p'iston connected with said movable cam portion,

(f) said casing having a uid pressure actuated piston chamber reciprocably carrying said piston,

(g) said movable cam portion -comprising an elongated member having one end operably connected with said piston delivery pressure,

(h) said piston having an effective area variably subject to pump delivery pressure and in opposition to pressure acting on the end of said elongated member, and

(i) said piston effect-ive area being larger than the effective area of the end of said elongated member.

5. A variable delivery pump comprising (a) a casing having a pumping chamber,

(c) cam means contacting and guiding said vanes for sliding operation as said rotor turns, said cam means having a iixed portion and a movable portion,

(d) means displacing said movable portion toward and away from said rotor, and

(e) means resiliently urging said movable portion toward said rotor at least when the rotor is stationary.

6. A variable delivery pump comprising (a) a casing having a pumping chamber,

(c) a fixed cam member carried in said chamber and having a cam surface concentric `with said rotor and provided with angularly spaced ends,

(d) a movable cam member slidably carried by said fixed cam member adjacent one end thereof,

(e) a ramp member hingedly carried by said other cam member and disposed intermediate the second end of the fixed ca-m member and the movable cam member, and

(f) said cam members and said ramp member contact- 10 ing and guiding said vanes for sliding operation as said rotor turns.

7. The pump as defined in claim 6 and in which (a) said movable cam member has a laterally extending semi-cylindrical socket `on one end,

(b) said ramp section has a laterally extending semicylindrical end shaped complementary to and engaged in said socket for hinging movement therein,

(c) said fixed cam member has means resiliently urging said ramp member toward said movable cam member to retain the end of the lramp member in said socket.

8. The pump as defined in claim 6 and in which (a) said fixed cam member cam surface is spaced from and substantially concentric with said rotor,

(b) said movable cam member is slidable between a first position substantially angularly coextensive with the fixed cam member cam surface to a second position close to the peripheral surface of said rotor whereby to vary pump delivery between substantially no delivery in the first position and selected maximum delivery in the second position.

9. The pump as defined in claim 8 and including (a) piston means operably connected with said movable cam member,

(b) valve means carried by said movable cam member and operable to variably direct pump delivery pressure to said piston means proportionately as delivery pressure varies to thereby variably adjust said movable cam member intermediate the aforesaid positions.

10. The pump 'as defined in claim 8 and including (a) means at all times resiliently urging said movable cam member toward said second position, and

(b) means automatically overcoming said resiliently urging means land adjusting said movable cam member intermediate the aforesaid positions proportionately with pump delivery pressure to vary delivery from said pump.

11. A variable delivery pump comprising (a) a casing having a pumping chamber,

(c) cam means having a cam surface contacting and guiding said vanes for sliding operating as said rotor turns and having means automatically varying the space between a portion of said cam surface and the periphery of said rotor relative to delivery pressure of said pump to thereby vary delivery as demand var1es,

(d) a fluid inlet connected with said chamber adjacent one side of said cam surface portion and a iiuid outlet connected with said chamber adjacent the other side of said cam surface portion, and arranged to produce fluid iiow into the inlet and out the outlet variably as said space varies between the cam surface portion and the rotor,

(e) a secondary fluid inlet and a secondary fluid outlet open to the chamber intermediate the first inlet and outlet and arranged to produce a small fluid iiow into and out of said chamber by vane operation when iiuid flow out of the first outlet is at a minimum.

References Cited by the Examiner UNITED STATES PATENTS 1,127,758 2/ 1915 Hansen-Ellehammer 103-120 2,238,062 4/1941 Kendrick 10B-120 2,313,075 3/1943 Kendrick et al. 103-120 2,538,193 1/1951 Ferris 103-120 3,085,514 4/1963 Budzich 103-173 3,120,814 2/1964 Mueller 103-120 MARK NEWMAN, Primary Examiner.

WILBUR I. GOODLIN, Examiner.

Claims

1. A VARIABLE DELIVERY PUMP COMPRISING (A) A CASING HAVING A PUMPING CHAMBER, (B) A ROTOR IN SAID CHAMBER AND HAVING ANGULARLY SPACED SLIDABLE VANES CARRIED BY SAID ROTOR, (C) CAM MEANS CONTACTING AND GUIDING SAID VANES FOR SLIDING OPERATION AS SAID ROTOR TURNS, SAID CAM MEANS HAVING A FIXED PORTION AND A MOVABLE PORTION, AND (D) MEANS DISPLACING SAID MOVABLE PORTION TOWARD AND AWAY FROM SAID ROTOR, (E) SAID MOVABLE CAM PORTION HAVING A LATERALLY EXTENDING SEMI-CYLINDRICAL SOCKET AT ONE END, (F) SAID CAM MEANS INCLUDES A RAMP SECTION HINGED ON AN AXIS EXTENDING PARALLEL TO SAID ROTOR AXIS, (G) SAID RAMP SECTION HAVING A LATERALLY EXTENDING SEMI-CYLINDRICAL END SHAPED COMPLEMENTARY TO AND ENGAGED IN SAID SOCKET FOR HINGING MOVEMENT THEREIN, AND (H) MEANS RESILIENTLY URGING SAID RAMP SEMI-CYLINDRICAL END INTO SAID SEMI-CYLINDRICAL SOCKET AT ALL TIMES.