US3244110A - Pump - Google Patents

Description

P. A. LEE

April 5, 1966 PUMP 4 Sheets-Sheet 1 Filed Jan. 15, 1965 IN VENTOR BY 5 M. T M -7 ATToRNE1/s P. A. LEE

April 5, 1966 PUMP 4 Sheets-Sheet 2 Filed Jan. 15, 1965 INVENTOR Pa A 455,

ATTORNEYS April 5, 1966 P. A. LEE 3,244,110

PUMP

Filed Jan. 15, 1965 4 Sheets-Sheet 5 pauz. fl. 455,

INVENTORS BY 6%, M M y A kw ATTORNEYS P. A. LEE

April 5, 1966 PUMP 4 Sheets-sheaf. 4

Filed Jan. 15, 1965 INVENTORS ATTORNEYS United States Patent 3,244,110 PUMP Paul A. Lee, Chicago, IlL, assignoito The Planet Prodnets Corporation, (Ihicago, I ll., a corporation of Illinois Filed Ian. 15, 1965. Ser. No. 427,212 11 Claims. (Cl. 103-126) aligning the shafts so thatthey will operate in parallel with each'other. Of course, if sufficient time, skill and effort are spend in machining and assembling the pump, the gear shafts can be mounted substantially in parallel, but the'time and effort necessary to construct such a pump is expensive. toprovide an inexpensive gear pump in which the gear shafts are located sufficiently parallel to permit the pump to operate efiiciently at high pressures.

Furthermore, the bearings and gears of fluid pumps are subject to wear and periodically must be replaced. Attempts have been made to prolong the life of the bearings and the gears with some success, but when the bearings finally become worn,-the pumps must be substantially rebuilt.

Attempts-have beenmade to produce lightweight, reliable gear pumps in which the gears and other components are formed of plastic. The plastic gears in the pumps are resistant to corrosion and, therefore, these pumps are particularly well suited for the pumping of food products or other liquids which may corrode a conventional pump. A lightweight, efficient plastic pump, however, must be sufficiently rugged to withstand the high internal fluid pressure, and the torque and vibration than-smitted to the pump from an electric motor.

Accordingly, it is an object of this invention to improve the alignment of the mounting of gear pump shafts ,and to maintain these in substantial alignment.

It is a further object of this invention to provide a construction in which wear and strain of the gear mountings is minimized. It is another object of this invention to provide a gear pump which is capable of pumping athigh pressures, and yet, is inexpensive to manufacture and economical to maintain.

These objects are accomplished in accordance with a preferred embodiment of the invention in which the drive gear of the pump is secured to a drive shaft and the idler gear is mounted on an idler shaft. The gears have substantially the same width. The idler shaft and drive shaft are mounted in end plates on opposite sides of the gears. The end plates are identical in size and shape and the holes for the shafts are line reamed through both end plates simultaneously so that they are in alignment. Bearing inserts are mounted in the shaft holes in the end plates to support the shafts for rotation. Replaceable liner plates are interposed between the end plates and the gears to form wear surfaces. The housing of the pump is formed to accommodate the outer configuration of the end plates. The side walls of the housing enclose the gears and end plates assembled within the housing and the most critical dimensions, the mountings for the gear shafts, are fixed by the end plates.

This preferred embodiment of the invention is illustrated in the accompanying drawings in which:

FIG. 1 is a perspective view of a pump embodying this invention;

Consequently, it has not been possible 3,244,119 Patented Apr. 5, 1966 FIG. 2 is an exploded view in perspective of the gear mounting arrangement;

FIG. 3 is a cross-sectional view of the pump along the line 3-3 in FIG. 4;

FIG. 4 is a cross-sectional view of the pump along the line 4-4 in FIG. 3;

FIG. 5 is a cross-sectional view of a modified form of the pump along the line 5-5 in FIG. 8;

FIG. 6 is a cross-sectional view of a portion of the modified form of the pump along the line 6-6 in FIG. 8;

FIG. 7 is a detail elevational view of a portion of the end cover of the modified form of the pump;

FIG. 8 is an elevational view of the valve end of the modified pump;

FIG. 9 is a detail sectional view along the line 9-9 in FIG. 5 showing an end plate and a portion of the housing of the modified pump;

- FIG. 10 is a top plan view of the sub-base; and -FIG. 11 is a cross-sectional view of the sub-base along the line 11-11 in FIG. 10.

The gear pump shown as an embodiment of this invention, includes a housing 2 through which is provided an inlet opening 4 and an outlet opening 6. Transverse conduits 8 and 10 extend through the housing intersecting the inlet opening 4 and outlet opening 6, respectively, to distribute fluid within the housing. The base of the housing is provided with a conventional pad 12 for supporting the housing in an upright position. Two bores 14 and 16 extend through the housing. The bores are substantially parallel and in vertical alignment, and the center distance between the axes of the bores is approximately the center distance of the gears of the pump.

A drive gear 18 is secured to a drive shaft 20, which is preferably metal, by any suitable means, such as molding the gear 18 on the shaft 20 or by adhesively bonding the gear to the shaft. An idler gear 22 is secured to an idler shaft 24 and the size of the gears is such that when in mesh, they fit closely within the gear bores '14 and 16 respectively. The gear shafts are journaled in end plates 26 and 23. Each end plate is formed in a single piece and both of the end plates are substantially identical. Shaft holes 36 and 32 in which the gear shafts 20 and 24 are mounted are formed in both end plates in the same operation to insure that the shaft holes of each pair of holes are parallel with those of the other pair, and the holes of each pair have the same diameter and location. Bearing inserts 34 and 36 may be fitted, if desired or needed, in the shaft holes 30 and 32, respectively, as shown in FIG. 2. The identical bearing end plates 26 and 28 are mounted on opposite sides of the gears 18 and 20 to support the shafts 20 and 24. To prevent excessive wear between the gears and the end plates, liners 38 and 40 of substantially the same configuration as the end plates may be interposed between the end plates and the gears.

The opposite ends of the housing 2 are enclosed by end walls 42 and 44. A metal cover plate 46 is mounted between the housing 2 and the end wall 42. A plurality of sealing rings 47 prevent the leakage of fluid along the cover plate 46. The cover plate 46 is provided with openings which registerwith the conduits 8 and 10 to provide communication between the interior of the pump and a bypass conduit 48. An adjustable spring loaded valve 49 controls the flow of fluid through the bypass conduit 48. The end walls 42 and 44 are secured to the housing by bolts 50 which extend through the end walls 42 and 44, cover plate 46 and housing 2.

A boss 52 is provided on the end wall 44, and the drive shaft 20 extends through a bore in the boss. Conventional V-belt pulleys 56 are mounted on the drive shaft 20 and keyed to the shaft so that the pulleys 56 turn with the shaft 20.

Important features of this invention are that the pump is light in weight, efiicient exen at high pressures, and yet inexpensive to manufacture, and that it requires a minimum of maintenance. The optimum benefits of this invention are obtained if unstressed parts are molded of a light weight thermoplastic and by use of thermoplastic to mold the pump parts, no drilling of the end plate bearings is required. The thermoplastic resin should have good dimensional stability and be capable of being molded to close tolerances. One thermoplastic resin which has been found particularly suitable is Delrin acetal resin which is available commercially from E. I. .du Pont de Nemours and Company.

The parts of the pump which are preferably molded of thermoplastic resins are the housing 2, end walls 42 and 44, end plates 26 and 28, drive gear 18, idler gear 22, and pulleys 56. The parts which are preferably made of metal are the drive shaft 20, idler shaft 24, cover plate 46, bearing inserts 34 and 36, bolts 50 and the liners 38 and 40.

Any type of suitable bearing material may be used in the bearing inserts, including mica, sinter-ed bronze impregnated with oil, or steel backed bearings coated with Teflon. For simplicity of manufacture and assembly, the pump is symmetrical about its vertical and horizontal axes, except for the end walls, the conduits 8 and 10, the the drive shaft and the pad on the housing. The use of end plates 26 and 28 which are substantially identical is an important feature of the invention for obtaining close tolerances at a minimum of cost. These end plates provide increased efficiency, especially in high pressure and increased alignment, thereby eliminating possible friction and wear whch results in less maintenance problems and increase life use. The outer edges of the end plates fit within the horizontal bores of the housing 2. The end plates 26 and 28 are molded on the same die and, therefore, havethe same dimensions within a close tolerance.

This assures that corresponding holes in the opposite end plates will have the same diameter and will be located at the same position in the end plates. The end plates provide the sole support for the drive shaft and the idler shaft and, since they are symmetrical and substantially identical, the shafts are parallel and the proper center distance when mounted between the end plates. This construction permits a high pressure pump to be manufactured without the high costs of precision jigs and fixtures usually found necessary to achieve the accurate mounting of the shafts.

Interchangeable bearing mountings, as are provided by the removable end plates, permit various sizes of gears to be used with each size of pump housing. The end plates may be made of different thicknesses to fill the space between the gears and the end walls thereby causing more or less quantity of liquid pumped, effecting a saving in tool costs for sizes adjacent thereto. Furthermore, various types of bearings may be inserted in the shaft holes of the end plates according to the anticipated operating conditions of the pump.

Another important feature of the invention is that if wear occurs, the pump may be easily disassembled and the worn parts may be replaced easily. Liners 38 and 40 are removable as are the bearing inserts 34 and 36. This pump is therefore inexpensive to maintain, light in weight and low in initial cost, and yet, is capable of pumping fluid at high pressure.

A modified form of the pump of this invention is illustrated in FIGS. to 11. As shown in FIG. 5, the modified form of the pump has a housing 60 which is substantially the same as that of the pump shown in FIGS. 1, 3 and 4. Within the housing 60, a drive gear is molded on a round drive shaft 64. The drive shaft 64 is preferably formed of metal and has a flat or splines formed in the shaft at the location where the drive gear 62 is molded on the shaft 64 to prevent the gear from turning relative to the shaft. The drive shaft 64 is journaled for rotation in bearing inserts 66, which are supported in the housing 60 by end plates 68 and 70 on opposite sides of the gear 62. An idler gear 72 is molded on an idler shaft 74-, which also has a flat or splines formed in the shaft for preventing rotation of the gear relative to the shaft. The idler shaft 74 is journaled for rotation in bearing inserts 76 which are mounted in the end plates 68 and 70, and the idler shaft '74 is spaced from the drive shaft 64 an appropriate distance for the gears 62 and 72 to be in mesh.

The bearing inserts 66 and 76 are substantially longer than the thickness of the end plates 68 and 70 in which they are mounted, thereby providing a large bearing surface for journaling the respective shafts 64 and 74. The end plates 58 and 70 correspond to the end plates 26 and 28, as shown in FIGS. 3 and 4, and have substantially the same shape as the intersecting bores in the housing 60 for accurately positioning the gears in the proper relation to each other. The use of single end plates extending between the drive shaft and idler shaft on opposite sides of the gears reduces the end play of the gears. In order to prevent excessive wear or galling of the surfaces of the end plates 68 and 70, thin metal liners 78 and 80 are provided between the gears and the end plates.

High pressure fluid which leaks outwardly along the shafts 64 and 74 urges the end plates 68 and 70 toward the gears 62 and 72. Although the liners 78 and 80 protect the end plates from excessive wear, the lateral force on the gears causes their opposite faces to become worn and increases the power required to drive the gears 62 and 72. Accordingly, the end plates 68 and 70 each have a shoulder 81 extending around the edge of each end plate, as shown in FIG. 5. The shoulders 81 fit in corresponding grooves in the housing 6% and prevent displacement of the end plates toward the gears 62 and 72.

A cover 82 closes one end of the housng 60 and has a sleeve 84 extending outwardly therefrom. A plurality of sealing rings 86 are mounted in a cylindrical recess 88 in the sleeve 84 to prevent the leakage of fluid along the drive shaft. The rings 86, which may be formed of rubber or a plastic having a low coefficient of friction, are retained in the recess 88 by a spider 90. The drive shaft 64 is journaled in a needle bearing assembly 92 in the sleeve 84 and a seal 94 is mounted in the end of the sleeve adjacent the bearing 92. A carbon hearing may be substituted for the needle bearing assembly 92. When a viscous fluid is being pumped, any seepage would tend to impose a drag on the needle bearings, but will have no negative effect on the carbon bearing. Therefore the carbon bearing is preferred when a viscous fluid is being pumped.

The pump may be driven by an electric motor. Power is transmitted from the motor to the pump by a belt extending between pulleys on the pump and the motor. For this purpose, a V-belt pulley 96 is secured on the drive shaft 64. The pulley has a ball bearing assembly 98 mounted therein. The inner race of the bearing assembly is pressed on the sleeve 84, which supports the pulley 96 for rotation, so that the belt groove is substantially in the same plane as the bearing assembly 92 and the drive shaft 64 is not bent or distorted by tension in the drive belt. The pulley 96 is secured on the drive shaft 64 in a suitable manner, as by a snap ring 99 and a key 100 which is inserted in a keyway in the shaft and cooperates with a keyway in the pulley 96. The shaft 64 extends beyond the pulley, as shown in FIG. 5, so that the shaft 64 may be directly coupled to another shaft, if desired.

As the pulley rotates, air circulation is induced through axially extending holes 191 in the pulley for cooling the bearing assembly 98. These holes 101 are spaced about the axis of the pulley in number and size suflicient for adequate ventilation and air circulation. They should extend substantially from the space between the bearing races. Furthermore, since the pulley is mounted on the sleeve 84, rather than directly on the shaft 64, the heat from the belt friction is not transferred from the pulley to the shaft 64.

At the opposite end of the housing 60, a cover 102 is secured overthe end of the housing. A gasket 104, preferably formed of metal, is interposed between the cover 162 and the housing 66. The cover 102 has bosses 106 formed thereon and cylindrical recesses 108 are provided in the bosses in the cover 102 for receiving the ends of the drive shaft 64 and the idler shaft 74, and their corresponding bearing inserts 66 and 76. A plurality of ribs 110 provide additional support for the bosses 166. A similar boss 112 is provided on the opposite cover 82 for receiving the opposite end of the idler shaft 74 and the bearing insert 76 in a cylindrical recess 114 in the boss 112. 1

In high pressure pumps, it is necessary to provide a bypass for the fluid to prevent excessive pressure from building up within the pump. As shown in FIG. 8, the pump has an inlet opening 116 and an outlet opening 118, correspondingto the inlet opening 4 and the outlet opening 6 of the pump shown in FIG. 3. The openings 116 and 118 extend into the interior of the housing 61! for supplying fluid to the gears 62 and 72 and for conducting the high pressure fluid out of the housing, respectively. A transverse bore 120 in the pump housing 60 communicates between the outlet opening 118 and the gasket 104, as shown in FIG. 6. The gasket 104 has a hole 122 which is in alignment with the bore 12%, and a cylindrical projection 124 formed on the cover has a central bore 125 in axial alignment with the hole 122. A plurality of longitudinal ribs 126 in the bore 125 form a cage for a ball 128 forming a valve. The diameter of the ball 128 is slightly larger than the diameter of the hole 122 and the hole forms a seat against which the ball is yieldably urged by a spring 132.

The end of the spring 130 is retained in a socket formed in a stud 132. The cylindrical projection 124 has internal threads which cooperate with external threads on the stud 132 and by turning the stud relative to the cylindrical projection, the force of the spring on the ball 128 may be adjusted. A hexagonal socket 134 is provided in the stud 132 to receive a wrench for turning the stud relative to the cylindrical projection 124. A cap 136 has internal threads which also cooperate with external threads on the stud 132, and a washer 138 is compressed between the cap and the projection when the cap is tightened against the end of the cylindrical projection 124. The stress on the threads of the stud 132 due to the compression of the washer 138 prevents the stud from turning, although the pump is vibrating severely. After the tension in the spring 130 has been adjusted, the stud 132 should remain in its adjusted position, but if the wrench socket 134 is exposed, it is an invitation for someone to insert a wrench in the socket and turn the stud 132. The cap 136, therefore, is provided to enclose the stud 132 and to shield it.

As shown in FIG. 8, a passageway 140 is formed in a rib 142 in the cover 102. The passageway 140 extends between the bore of the cylindrical projection 124 and a transverse bore in a projection 141 on the cover 102, which transverse bore in the projection 141 registers with a transverse bore 144 in the housing 60 which in turn communicates with the inlet opening 116. Consequently, if the fluid pressure in the outlet side of the pump is sufliciently high to displace the ball 128 from its seat in the hole 122, fluid is bypassed to the low pressure, intake side of the pump through the bore 120, the passageway 140 and the bore 144. The pressure at which fluid begins to bypass may be adjusted by turning the stud 132 to vary the tension of the spring 130 on the ball 128.

Since the fluid pressure in the pump may cause leakage of fluid from the gears 62 and 72 outwardly through their respective bearing inserts 66 and 76, the cylindrical recesses in the bosses 106 and 112 are substantially larger than the diameter of the bearing inserts and are spaced away from the ends of the bearing inserts and the shafts to allow leakage fluid to accumulate in the cylindrical recesses in the covers. There is suflicient space between the inserts and their respective cylindrical recesses to allow for expansion of the fluid in the recesses. The fluid pressure at the outlet of the pump is greater than the fluid pressure at the inlet of the pump when the pump is in operation and this pressure difference maybe utilized to return the leakage fluid to the ,inlet side of the pump. Each of the end plates 68 and 70 has a transverse groove 146, as shown in FIGS. 5 and 9, in the side opposite the gears 62 and 72. The groove extends from the center of the end plate to the low pressure side of the end plate, so that leakage fluid can flow between the end plate 68-or 7t) and the housing 60 and into the inlet opening adjacent the gears. The flow of leakage fluid also cools the bearings and the shafts. This is the point of lowest pressure in the ump, and accordingly, and leakage of fluid through the ends ofthe bearing inserts will flow through the grooves 146 and back to the inlet side of the pump, thereby preventing fluid from leaking out of the housing 60. The shoulders 81 prevent the end plates from being displaced toward the sides of the gears by the high pressure of the fluid at the outer ends of the bearing inserts.

As shown in FIGS. 5 and 7, right-angular ribs 148 extend outwardly from thecover 82 adjacent to each bolt hole 150, which extends through the covers and the housing. The ridges 148 are spaced from the bolt holes 150 sufficiently to embrace the head of'a bolt 152 which extends through the bolt hole 150 and clamps the covers 82 and 102 to the housing 60. The ribs 148 adjacent each bolt hole 150 prevent the head of the bolt from turning while a nut 154 is being threaded on the bolt.

In order to provide better stability for the pump housing 60, the housing base 155 may-be mounted on a sub-base 156, as shown in FIGS. 5, 8, l0 and 11. The sub-base 156 has right angular ribs 158, which are spaced a distance corresponding to the length and width of the base 155 of the housing 60, so that the base of the housing may be supported between the ribs 153. Bolt holes 160 are provided in opposite ends of the sub-base 156 in alignment with corresponding holes in the base 155 of the housing 66, for clamping the housing against the sub-base 156. One of the bolt holes may be in the form of a slot to compensate for inaccurate spacing of the holes in the housing. Bolt holes 162 are also provided in the-outer ends of the sub-base for securing the sub-base to a motor platform or other support.

In operation, the pump of this invention is mounted adjacent an electric motor and a drive belt extends between the motor pulley and the pulley 96 for rotating the drive shaft 64. A fluid inlet line is connected to the inlet opening 116 and an outlet line is connected to the outlet opening 118. The bypass valve is adjusted by turning the stud 132 until the spring force on the ball 128 is suflicient to maintain the ball against its seat at lower pressures, but the ball is displaced away from the hole 122 at the desired outlet fluid pressure. The cap 136 is then replaced on the projection 124 for locking the stud 132 against rotation. When the motor turns the pulley 96, the gears 62 and 72 are rotated and fluid flows through the pump in paths from the inlet side of the pump between the gear teeth and the housing 60 to the outlet side of the pump. The region between the gears on the inlet side of the pump is at a low fluid pressure, while the area between the gears on the outlet side of the pump is at a relatively high fiuid pressure when the pump is in operation.

While this invention has been illustrated and described in certain embodiments, it is recognized that variations and changes may be made therein without departing from the invention as set forth in the claims.

I claim:

1. A gear pump comprising a housing, fluid inlet and outlet openings on opposite sides of the housing, parallel bores through the housing, a drive gear in one of the bores, an idler gear in the other bore in mesh with the drive gear, said drive gear being secured on a drive shaft, an end wall secured to the housing over the bores, said drive shaft extending through the end wall, said end wall having a sleeve extending outwardly therefrom in surrounding relation to said shaft, a pulley having a belt groove therein, first bearing means mounting the pulley for rotation on said sleeve, said belt groove being in substantially the same plane as said bearing means, second bearing means between said sleeve and said shaft, said second bearing means being in substantially the same plane as said first bearing means and said belt groove, and means for connecting said pulley to said drive shaft.

2. A gear pump according to claim 1 wherein said sleeve includes a cylindrical recess coaxial with said shaft and said second bearing means being mounted in said recess, and fluid sealing means on opposite sides of said second bearing means.

3. A gear pump according to claim 2 wherein said second bearing means is a needle bearing assembly and said pulley has openings extending axially therethrough for cooling said first bearing means.

4. A gear pump comprising a housing, fluid inlet and outlet openings on opposite sides of the housing, parallel bores through the housing, a drive gear in one of the bores, an idler gear in the other bore in mesh with the drive gear, said drive gear being secured on a drive shaft, said idler gear being mounted on an idler shaft, end plates in the bores, each of said end plates having a uniform thickness and planar opposite faces and being in one integral piece and extending between and encircling the drive shaft and the idler shaft, bearing inserts in said end plates in position for journaling said drive shaft and said idler shaft, said bearing inserts having a greater length than the thickness of said end plates, and a cover secured to said housing over said bores, said cover having cylindrical recesses therein in position to receive said bearing inserts and said drive shaft and idler shaft, said recessesbeing spaced radially from the respective inserts and shafts for receiving leakage fluid therebetween.

5. A gear pump according to claim 4 wherein said end plates each have radial shoulders thereon in position for engaging said housing and said recesses individually enclose said inserts and shafts.

6. A gear pu-mp comprising a housing, fluid inlet and outlet openings on opposite sides of the housing, parallel bores through the housing, a drive gear in one of the bores, an idler gear in the other bore in mesh with the drive gear, said drive gear being secured on a drive shaft, said idler gear being mounted on an idler shaft, end plates in the bores, each of said end plates having planar opposite faces and being in one integral piece and extending between and encircling the drive shaft and the idler shaft, said end plates having grooves therein on the side opposite said gears, said grooves extending from between said idler shaft and drive shaft to the edge of the end plate adjacent the fluid inlet opening, whereby fluid adjacent the outer side of each end plate is maintained under relatively low pressure.

7. A gear pump according to claim 6 wherein said grooves are formed in said end plate faces on the side opposite said gears, each of said grooves being substantially straight and extending perpendicular to a line in the plane of each face and interconnecting the central axes of said gears.

8. A gear pump comprising a housing, fluid inlet and outlet openings on opposite sides of the housing, parallel bores through the housing, a drive gear in one of the bores,

an idler gear in the other bore in mesh with the drive gear, said drive gear being secured on a drive shaft, said idler gear being mounted on an idler shaft, end plates in the bores, each of said end plates having planar opposite faces and being in one integral piece and extending between and encircling the drive shaft and the idler shaft, a cover extending over said intersecting bores, said housing having a pair of transverse passageways communicating independently with said cover, one of said passageways extending from said inlet to said cover and the other passageway extending from said outlet to said cover, said cover having a conduit therein communicating between said transverse passageways, value means in said conduit, said valve means tending to open in response to a fluid pressure differential between the pressure of the fluid in said outlet opening and the fluid in the inlet opening, a coil spring in said cover in position for yieldably urging said valve means closed, a stud engaging one end of said spring and being threaded in said cover and a cap threaded on the stud on the end opposite the spring, whereby the stud adjusts the spring force and the cap engages the cover and locks the stud in its adjusted position.

9. A gear pump according to claim 8 wherein said stud has a hollow recess in one end for receiving said coil spring and a wrench socket in the opposite end.

10. A gear pump comprising a housing, a fluid inlet and outlet openings on opposite sides of the housing, parallel bores through the housing, a drive gear in one of the bores, an idler gear in the other bore in mesh with the drive gear, said drive gear being secured on a drive shaft, said housing having a base integral therewith for supporting the housing in an upright position, a platform, and means for fastening the base to the platform, said platform having upstanding ribs extending along said base, whereby the platform rigidly supports the base while the pump is in operation.

11. A gear pump comprising a housing, fluid inlet and outlet openings on opposite sides of the housing, parallel bores through the housing, a drive gear in one of the bores, an idler gear in the other bore in mesh with the drive gear, said drive gear being secured on a drive shaft, a cover on each opposite end of the housing extending over the intersecting bores, and bolts extending through said covers and said housing for clamping the covers to the housing, said bolts having heads with at least one flat side, one of said covers having ridges extending along the flat side of the heads of said bolts, whereby the bolts are prevented from turning while a nut is being tightened on the opposite end of each bolt.

References Cited by the Examiner UNITED STATES PATENTS 2,682,836 7/1954 Orr 103-126 2,714,856 8/1955 Kane 103-126 2,728,301 12/1955 Lindberg 103-126 2,772,638 12/1956 Nagely 103-126 2,823,616 2/1958 Toyoda 103-126 2,880,676 4/1959 Succop 103-126 2,986,097 5/1961 Chrzanowski 103-126 2,996,998 8/1961 Gold et al 103-126 3,057,302 10/1962 Lockett 103-126 3,077,840 2/1963 Wood -1 103-126 3,113,524 12/1963 Fulton 103-126 3,128,710 4/1964 Blomgren et al 103-126 MARK NEWMAN, Primary Examiner.

WILBUR J. GOODLIN, Examiner,

Claims (1)

1. A GEAR PUMP COMPRISING A HOUSING, FLUID INLET AND OUTLET OPENINGS ON OPPOSITE SIDES OF THE HOUSING, PARALLEL BORES THROUGH THE HOUSING, A DRIVE GEAR IN ONE OF THE BORES, AN IDLER GEAR IN THE OTHER BORE IN MESH WITH THE DRIVE GEAR, SAID DRIVE GEAR BEING SECURED ON A DRIVE SHAFT, AN END WALL SECURED TO THE HOUSING OVER THE BORES, SAID DRIVE SHAFT EXTENDING THROUGH THE END WALL, SAID END WALL HAVING A SLEEVE EXTENDING OUTWARDLY THEREFROM IN SURROUNDING RELATION TO SAID SHAFT, A PULLEY HAVING A BELT GROOVE THEREIN, FIRST BEARING MEANS MOUNTING THE PULLEY FOR ROTATION ON SAID SLEEVE, SAID BELT GROOVE BEING IN SUBSTANTIALLY THE SAME PLANE AS SAID BEARNG MEANS, SECOND BEARING MEANS BETWEEN SAID SLEEVE AND SAID SHAFT, SAID SECOND BEARING MEANS BEING IN SUBSTANTIALLY THE SAME PLANE AS SAID FIRST BEARING MEANS AND SAID BELT GROOVE, AND MEANS FOR CONNECTING SAID PULLEY TO SAID DRIVE SHAFT.

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