US3186350A - Fuel pump - Google Patents

Description

June 1965 J. B. FITZGERALD 3,185,350

FUEL PUMP Filed April 29, 1963 INVENTOR. JOHN B. FITZGERALD I BY M3 F 5 W AGENT United States Patent 3,186,350 FUEL PUM? John E. Fitzgeraid, St. Louis, Mo assignor to ACF Industries, Incorporated, New York, N.Y., a corporation of New Jersey Filed Apr. 29, 1963, Ser. No. 276,470 14 Claims. (Cl. 10315tl) This invention relates to fuel pumps, and more particularly to an automotive fuel pump for pumping automotive fuel from the fuel tank of an automotive vehicle to the carburetor of the internal combustion engine of the vehicle.

An automotive fuel pump is typically a diaphragm pump having a pumping chamber closed by a diaphragm with a compression spring for driving the diaphragm in one direction through its discharge stroke and a diaphragm actuating rod or stem connected to the diaphragm for returning the diaphragm through its suction stroke in the opposite direction. A rocker arm actuated by an enginedriven cam engages a head on the end of the actuating rod and moves the actuating rod positively through the suction stroke of the diaphragm, and upon the diaphragm reaching the end of its suction stroke the compression spring returns the diaphragm and its actuating rod through the discharge stroke of the diaphragm. On strokes of the diaphragm less than a full stroke, the rocker arm idles for part of its cycle in regard to the diaphragm actuating rod and moves out of contact with the head on the actuating rod. This occurs, for example, when there is low demand for fuel by the carburetor, and a full discharge stroke of the diaphragm is not obtained. Since the rocker arm is driven directly by a cam on the engine, the speed of rocker arm oscillation and the force produced by the rocker arm on the head of the operating rod will be proportional to the engine speed. As the speed of the engine increases, the head of the rod will move into lever arm contacting position more often due to an increase in fuel consumption by the engine. At high engine speeds therefore the strike of the lever arm against the head of the operating rod not only will occur more often than at low engine speeds, but also will cause a very severe shock when contact is made. This results in a very high rate of wear on the rocker arm and the head of the operating rod. The operating life of the diaphragm is also limited by the severity and shock of the operating action involved.

In normal operation, the rocking arm of a fuel pump of the type described not only claps or contacts the head of the operating rod with a very high impact, as mentioned above, but also produces a high level of operating noise. As the parts begin to wear and tolerances increase, there is an even further increase in the noise level involved in normal operation. It is desirable that the noise level of a modern automotive engine as well as other internal combustion engines be kept at a low level and that fuel pump noise be greatly reduced. Fuel pump noise is also very annoying when the engine is running at idle or low operating speeds, when background noises such as road noise and noise caused by Wind are not present. Another consideration involving fuel pump noise concerns the rocker arm pivot. Normal wear on the rocker arm pivot in fuel pumps of the type described is likely to result in unduly noisy rattling. Rattling of the rocky arm on its pivot also accelerates wear and reduces the life of the fuel pump.

It is, therefore, an object of this invention to provide a fuel pump wherein the noise produced by the lever arm striking the head of the operating rod is minimized at all speeds of engine operation.

Another object of this invention is the provision of a fuel pump construction wherein the rate of wear on the parts is minimized, thus increasing the normal expected operating life of the fuel pump.

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It is among the objects of this invention to provide a fuel pump wherein excessive noise in the action of the rocker arm pivot is minimized and wherein excessive accelerated wear of the rocker arm on its pivot is also minimized.

In general, these objects are attained by providing the rocker arm of the pump with a generally rigid or non-flexible shock absorbing member pivoted intermediate its ends on the rocker arm and having a free end biased away from the free end of the rocker arm. The free end of the piv oted member is interposed between the arm and the head on the diaphragm actuating rod and cushions the impact of the rocker arm on the head thereby to muffle the noise which would otherwise occur. A spring biases the free end of the pivoted rigid shock absorbing member away from the arm and also serves to bias the rocker arm into engagement with the engine-driven cam. Rattling of the rocker arm on its pivot after wear has occurred is minimized by the arrangement of this spring. Other objects and features will be in part apparent and in part pointed out hereinafter.

The invention accordingly comprises the constructions hereinafter described, the scope of the invention being indicated in the following claims.

In the accompanying drawings, in which one of the various possible embodiments of the invention is illustrated,

FIG. 1 is a view in elevation illustrating a diaphragm pump of this invention in use on the engine of an automotive vehicle;

FIG. 2 is a vertical section of the pump apart from the engine shown in FIG. 1, parts being shown in their position at the end of a discharge stroke;

FIG. 3 is a fragment of FIG. 2, showing parts in another position;

FIG. 4 is an enlarged fragmentary section similar to FIG. 3, showing parts in the same position as FIG. 2; and

.FIG. 5 is a section taken on line 5-5 of FIG. 3.

Corresponding reference characters indicate corresponding parts throughout the several views of the drawings.

Referring to the drawings, there is indicated in FIG. 1 at E the engine of an automotive vehicle on which is mounted a fuel pump P constructed in accordance with this invention. Fuel is delivered from fuel tank T of the vehicle through a line L1 to the fuel pump P and delivered by the latter through a line L2 to the carburetor C for the engine. The carburetor is mounted on the intake manifold of the engine, and an air-filter F is shown mounted on the air horn of the carburetor.

As shown in FIG. 2 pump P comprises a rocker arm housing 1 which is open at one end (its left end as appears in FIG. 2), this end being referred to as the inner end of the housing. The housing is of generally rectangular form in vertical cross section and of decreasing height from its inner end to its outer end (which is closed). At its inner end is a flange 3 for attaching it to the engine E. A rocker arm 5 is pivoted at 7 in the housing for rocking motion on a horizontal axis transverse to the housing. Arm 5 has an end portion 5A projecting out of the open inner end of the housing and an opposite end portion 513 within the housing 1. When the pump is mounted on the engine, end portion 5A of the rocker arm is engaged by an enginedriven eccentric or cam 11. On rotation of the cam through half a revolution from its FIG. 2 position (wherein the low point of the cam engages portion 5A of the rocker arm), the rocker arm is rocked clockwise from its FIG. 2 position.

Extending upward from the rocker arm housing 1 at its outer end is a hollow conical pump base 13. An opening 15 is provided between the interior of housing 1 and the upper plate.

the hollow base 13 at the bottom of the latter. The conical base .13 has an outwardly projecting rim or flange 17 at its top. The top of flange 17 constitutes a seating surface for the margin of an annular diaphragm 19 consisting of a relatively thin disk of flexible fuel resistant material, such as a suitable synthetic rubber, which, when in unstressed condition, is flat or substantially flat. The outer margin of the diaphragm is clamped against the top of flange 17 by a pump body generally designated 21 having an outwardly projecting flange 23. Bolts 25 extending through flanges 17 and 23 draw flanges 17 and 2,3 together against the margin of the diaphragm under suflicient pressure to provide a fuel-tight seal all around the margin of the diaphragm and maintain pump body 21 in assembly with base 13. a

The diaphragm is adapted to be pulled or flexed downward by a diaphragm-actuating rod or stem 27 and to be pushed or flexed upward by a spring 29. Rod 27 extends downward through base 13 and through the opening 15 into the rocker arm housing 1. Portion B of the rocker arm has a bifurcated or forked free end 31 which receives the rod 27. The latter has a head 33 at its lower end constituted by a collar riveted in place at the lower end of the rod.

The rod extends slidably through an oil seal and rod guide 35 held in an annular recess at the bottom of the base 13 by the reaction on a seal retainer ring 37 of the spring 29, this spring being a coil compression spring surrounding the rod. The diaphragm is mounted on the upper end of the rod 27 between a pair of circular plates 59 and 41, plate 39 being the lower plate and plate 41 The lower plate is formed with an annular corrugation or rib 4-3 forming a seat for confining the upper end of spring 29, The lower plate is of larger diameter than the upper plate and the margin of the lower plate which overhangs the upper plate is flared outward and upward to provide a rim 45 constraining the diaphragm to have an annular, free, nonreversing loop 47. The upper plate has a curved rim 49 engaging the loop. In the upward position of the diaphragm illustrated in FIG. 2, the outside of the loop engages the inner sur face of the pump body 21. When arm 5 is rocked clockwise by cam 11, it lowers the rod and pulls the diaphragm downward. This loads the spring 29. Then when arm 5 rocks counterclockwise, spring 29 is adapted to drive the diaphragm and rod upward.

Pump body 21 is formed with a pumping chamber 53 above diaphragm 19. A partition 55 separates an inlet or intake chamber 57 from pumping chamber 53. A series of circular ports 59 provide communication from intake discharge check valve 73. 1 Line L2 is connected to an 7 outlet nipple '75 to supply fuel to carburetor C from discharge chamber 69 through passage 77.

Check valves 61 and 73 are of identical construction.

Each comprises a stem 79 press fitted at one end within hole 81 and having atits other end a mushroom head 83. A ring-shaped disk valve member 85, which may be made of a suitable fuel-resistant synthetic rubber for cushioned sealing, is slidable on the stem 79, and isbiased toward engagement with a valve seat formed by the adjacent face of ithe respective partition by acoil compression spring.

Rocker arm 5, as shown, is formed of sheet metal, having aweb portion 87 and side flanges such as indi: cated at 89 which extend upward from the web. The pivot at 7 is constituted by a pin extending betweenthe side walls of the rocker arm housing 1 and through holes in'flanges-89. "As to outer end portion 5B of the rocker arm, webfi? inclines upward and is bent as indicated at d 91 to form a pocket 92 on the lower sideof web 87. The forked free end of portion 53 of the rocker arm extends from bend 91 and is curved to present a convex lower surface from pocket 92. toward head 33.

The rocker arm is biased in the direction for engagement of its outer end portion 5A with cam 11 by a coil compression spring 93. This spring seats against the bottom of the rocker arm housing and against a shoulder 95 on the bottom of the rocker arm housing. A rivet 97 extends through an opening in web portion 37 and has an upper head 99 engaging the upper surface of web portion 87. A lower head 1411 on rivet 97 secures the upper end of coil spring 93 to web port-ion 87 at a position inward from pocket 92. Spring 93 is constrained into a curved form as appears in FIGS. 24. The upper end of coil spring 93 is freely slidable on rivet 97.

A generally rigid or non-flexible shock absorbing member designated generally 193 and formed of a bent metal strip has an inner end portion 195 inward of pocket 92 and a curved free outer end portion 197 which, like free end 31 of portion 53 of the rocker arm, is forked or bifurcated to receive rod 27. Pocket 92 forms a fulcrum or pivot for member 103 and member 103 is adapted to rock or pivot back and forth in pocket 92. Free outer end portion 107 presents 'a convex lower surface'toward head 33, while inner end portion 1115 is flat. Rivet 97 extends through an opening in inner end portion 1&5 in such a manner that the shock absorbing member 193 is freely slidable on rivet 97. The upper end of spring 93 seats against inner end portion to bias the latter against the adjacent flat surface of web 87 and thereby to bias outer free end portion 167 away from the adjacent free end 31 of rocker arm 5. Rivet 97 is loosely mounted on arm 5 and permits member 193 to pivot back and forth.

Operation is as follows:

The inner end 5A of rocker arm 5 is maintained in engagement with cam 11 by coil compression spring 93. On each revolution of the cam, the arm is pivoted clockwise from its FIG. 2 position, then returned counterclockwise to its FIG. 2rpositionb As arm 5 swings clockwise it pulls rod 27 downward to flex diaphragm 49 downward through a suction stroke; As it pivots counterclockwise, it permits rod 27 to move upward and permits diaphragm 49 to flex upward through a discharge stroke under the bias of spring 29. Free end portion 197 of member 103 is pivoted into engagement with the convex lower surface of free end 31 of therarm (see FIGS. 2 and 4) against the bias of spring 93 as inner end portion 105 of member 193 is pivoted or rocked away from engagement with web 87 of the rocker arm. 7

Upon a low demand for fuel by carburetor C, diaphragm 49 does not flex upward through a full discharge stroke to the position shown in FIG. 2, and rod 27 there fore remains in a downward position as shown in FIG. 3. As arm 5 swings upward away from head 33, spring 93 pivots member 193 clockwise relative to arm 5, inner end portion 195 engaging web 87 and outer free end portion 197 being pivoted out of engagement with free end 31 of arm 5 as appears in FIG. 3. On the next downstroke of free end 31 of rod 5, outer free end portion 197 strikes head 33 and member 193 is rocked against the bias of spring 93 to its FIG. 4 position. Thus, rigid member 163 in conjunction with spring 93 acts as a cushion or shock absorber for absorbing the shock and muifiing the noise which would otherwise occur on the striking of head 33 by free end 31 of arm 5. T

Spring 93 serves a'function in addition to its rocking of rigid member 1% as it urges rocker arm 5 continuously against the bottom of pin 7. This tendstotavoid rattling or chattering of rocker arm 5 such as might occur when wear occurs at pivot pin 7 and arm 5becomes loose on pin 7 with a tendency to move up and down on the pin.

In view of the above, it will be seen that the several objects of the invention are achieved and other advantageous results attained.

As various changes could be made in the above constructions without departing from the scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

What is claimed is:

1. In a pump having a pumping chamber, a diaphragm closing said chamber, a housing structure, a rod extending from the diaphragm and having a head on its extending end, a rocker arm for driving the rod and actuating the diaphragm in one direction, and a spring mounted on the rod interposed between the diaphragm and the housing structure for driving the diaphragm and the rod in the opposite direction, a generally rigid member mounted on the arm for pivotal movement relative to the arm and having a free end normally spaced from the arm and interposed between the arm and the head, and means biasing the free end of the rigid member away from the arm, the free end of the rig-id member being engageable with the head and pivoting toward the arm against the bias of said biasing means for muflling the impact of the arm against said head on a driving stroke thereof.

2. In a pump as set forth in claim 1, said arm and said rigid member each having a forked free end portion receiving the rod.

3. In a pump as set forth in claim 1, said biasing means comprising a spring engaging the rigid member and biasing the rigid member to swing in a direction to space the free end of the rigid member from the arm, said spring also bias-ing the rocker arm in the direction permitting the rod and diaphragm to move in said opposite direction.

4. In a pump as set forth in claim 3, the rigid member having an inner end portion interposed between the spring and the arm, the spring biasing the inner end portion against the arm, and a fastener securing the inner end portion and the adjacent end of the spring to said arm, the fastener permitting the inner end portion to move toward and away from the arm.

5. In a pump as set forth in claim 4, said rig-id member being a metal strip having a bend intermediate its ends and being pivoted on the arm at the bend.

6. In a pump as set forth in claim 1, the arm and said rigid member each having a bifurcated end portion receiving the rod and bent toward the head, the bifurcated end portion of the rigid member normally being spaced from the arm and being pivoted about its bend toward the arm upon engagement with the head of said rod.

7. In a pump as set forth in claim 6, the bifurcated end portions of the arm and rigid member are each of a curved form present-ing a convex surface toward the head.

8. A fuel pump comprising means defining a pumping chamber, a diaphragm closing the pumping chamber, a housing enclosing the diaphragm, a rocker arm housing extending laterally from the diaphragm housing, means in the diaphragm housing biasing the diaphragm in discharge direction, a diaphragm actuating rod extending from the diaphragm into the rocker arm housing and having a head on its extending end, a rocker arm for driving the rod pivoted in and extending longitudinally of said rocker arm housing, said arm having a bifurcated free end receiving the rod adjacent its head, and a generally rigid member mounted on the arm for pivotal movement relative to the arm and having a bifurcated free end generally in vertical alignment with the bifurcated free end of the rocker arm, the free end of the rigid member normally being spaced from the arm and interposed between the arm and the head, and means biasing the free end of the rigid member away from the arm, the free end of the rigid member being engageable with the head and pivoting toward the arm under the bias of said biasing means for muffiing the impact of the arm against said head on a driving stroke.

9. A fuel pump as set forth in claim 8 wherein said biasing means comprises a spring engaging the rigid member and biasing the rigid member in a direction to space the free end of the rigid member from the arm, said spring also biasing the rocker arm in the direction permitting the rod and diaphragm to move in said discharge direction.

10. A fuel pump as set forth in claim 9 wherein the rigid member has an inner end portion interposed between the spring and the arm, the spring biasing the inner end portion against the arm, and having a fastener securing the inner end portion and the adjacent end of the spring to said arm, the fastener permitting the rigid member to pivot on the arm.

11. A fuel pump as set forth in claim 8 wherein the bifurcated ends of the rod and rigid member are bent toward the head, the bifurcated end of the rigid member normally being spaced from the arm and being pivoted toward the arm upon engagement with the head of the rod on a driving stroke.

12. A rocker arm assembly for a fuel pump having a pump operating rod with a head thereon, said rocker arm assembly adapted to be mounted intermediate its ends for pivotal movement, said rocker arm assembly including a rocker arm having a free end portion thereof adapted for driving engagement with the head of the operating rod of said pump, said free end portion having a bend defining a pocket, a substantially rigid member movably connected to said rocker arm near said bend and adapted to pivot within said pocket, a biasing means normally biasing one end of said member in spaced relation with said arm, said one member end adapted to be interposed between said arm and said head, said one end of said member adapted to be engageable with said head and to pivot toward said arm against the bias of said biasing means to absorb the impact of the arm against said head.

13. A rocker arm assembly as set forth in claim 12, said rocker arm having side flanges, a web connecting said side flanges, said Web having a hole therein adjacent said pocket, a rivet extending loosely through said hole, said biasing means being a spring adapted for urging said rocker arm into engagement with said engine cam and out of engagement with the head of the operating rod, said spring and said rigid member being loosely mounted for sliding movement on said rivet whereby said spring also urges said one end of said member in spaced relation with said rocker arm.

14. A rocker arm assembly for an automotive fuel pump having a pump operating rod, said rod including a head at one end, said assembly comprising a rocker arm member having an engine cam engaging end and a free end, said rocker arm adapted to be pivotally mounted intermediate its ends with the head portion of said operating rod in the path of reciprocation of the free end of said rocker arm, a generally rigid member mounted on said rocker arm near said free end and having a portion thereof in pivotal engagement with said rocker arm, said member having one end thereof adapted to be interposed between said rocker arm and the head of said operating rod, biasing means biasing said one member end in normally spaced relation with said rocker arm, said free rocker arm end adapted to be engaged by said head and p voted toward said rocker arm against the bias of said biasing means to absorb and cushion the impact of said rocker arm against said head.

References Cited by the Examiner UNITED STATES PATENTS 2,469,818 5/49 Erickson 103-150 2,801,594 8/57 Lewis 103-215 X FOREIGN PATENTS 834,108 8/38 France.

LAURENCE v. EFNER, Primary Examiner. WARREN E. COLEMAN, Examiner.

Claims (1)

1. IN A PUMP HAVING A PUMPING CHAMBER, A DIAPHARGM CLOSING SAID CHAMER, A HOUSING STRUCTURE, A ROD EXTENDING FROM THE DIAPHRAGM AND HAVING A HEAD ON ITS EXTENDING END, A ROCKER ARM FOR DRIVING THE ROD AND ACTUATING THE DIAPHRAGM IN ONE DIRECTION, AND A SPRING MOUNTED ON THE ROD INTERPOSED BETWEEN THE DIAPHARGM AND THE HOUSING STRUCTURE FOR DRIVING THE DIAPHRAGM AND THE ROD IN THE OPPOSITE DIRECTION, A GENERALLY RIGID MEMBER MOUNTED ON THE ARM FOR PIVOTAL MOVEMENT RELATIVE TO THE ARM AND

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