US2889781A

US2889781A - Fuel pump

Info

Publication number: US2889781A
Application number: US472118A
Authority: US
Inventors: Tom H Thompson
Original assignee: SABRE RES CORP
Current assignee: SABRE RES CORP; SABRE RESEARCH Corp
Priority date: 1954-11-30
Filing date: 1954-11-30
Publication date: 1959-06-09
Anticipated expiration: 1976-06-09

Description

June 9, 1959 T. H. THOMPSON FUEL PUMP 2 Sheets-Sheet 1 Filed NOV. 30, I954 gag/V l N VENTOR 727/1/1. 77/0Mp5a/v,

ATTORNEY June 9, 1959 T. H. THOMPSON FUEL PUMP 2 Sheets-Sheet 2 Filed Nov. 30, 1954 ATTORNEY United States Patent FUEL PUMP Application November 30, 1954, Serial No. 472,118 4 Claims. (Cl. 103-38) This invention relates to a fuel pump, and more particularly to a fuel pump for a fuel injection system of the type described in my copending application Serial No. 383,538, filed October 1, 1953, now Patent No. 2,809,868.

In fuel pumps of the type to which the present invention is directed, three important features must be given consideration. The first is the cost of construction. In order for fuel injection systems to be universally adopted on automobiles today, the cost of the systems must be comparable to the present carburetor injection system.

Second, the system must have a long life, for example, comparable to operation of an automobile for 50,000 miles or the system will not be adopted.

Third, the system must have a reliability or uniformity of operation. This is particularly important at-idling speeds, for, at such speeds, the quantity of fuel injected with each stroke of the pump must be substantially the same as at every other stroke of the pump, otherwise the engine will not perform smoothly.

The pump according to the present invention is satisfactory with respect to all of the considerations mentioned above. Economy is provided by constructing the pump bellows from Belleville washers with a very simple but effective interconnecting arrangement. Thus, the expensive Sylphon bellows are eliminated as well as other very complicated pumping mechanisms.

A long life is designed into the pump, particularly into the critical bellows by providing a novel arrangement for interconnecting the Belleville washers, which permits the Belleville washers a limited freedom of movement with respect to each other and with respect to the inter connecting arrangement so as to prevent unnecessary stresses in the washers thereby reducing failure of the washers by fatigue.

Uniformity and reliability are provided both by the interconnecting arrangement referred'to above and by the bellows actuating linkage which: at idling speedslmaintains the bellows substantially completely collapsed. By this arrangement the bellow amount of fuel when the engine cal speed.

It is, therefore, an object of the present invention to provide a fuel pump which is economical to construct, has a long life, and is reliable and uniform in its performance. It is a further object of the invention'to provide a fuel pump in which the bellows therefor is'constructed from interconnected Belleville washers.

It is still a further object of the invention to provide an interconnecting arrangement for the washers'which eliminates unnecessary stresses during operation of the pump.

It is another object of the invention to provide a bellows actuating linkage which maintains all of the bellows in collapsed condition when the engine throttle is closed. J

It is still a further object of the invention to'provide a bellows which is substantially completely exhausted when in collapsed condition. 7

These and other objects will become more readily apoperates at its most critiv handles the minimum' parent from a consideration of the following detailed description of the invention taken in conjunction with the drawings in which:

Fig. 1 is a cross-sectional view taken through the center of the pump,

Fig. 2 is a cross-sectional view taken through the center of one of the bellows, and

Fig. 3 is a cross-sectional view similar to Fig. 2 showing the bellows in collapsed condition.

The pump is provided with a cylindrical casing 10 covered at the bottom with a plate 12 and at the top with a plate 14. The plates are joined to the cylindrical housing by bolts 16.

The top plate 14 is provided with outlet passageways 18 and intake passageways 28 for each piston to be supplied with fuel (arrangement for only two being shown). The outlet passageway 18 is provided with a one-way valve consisting of a check ball 20 biased by a spring 22. The outlet passageway is connected to an injector nozzle of some suitable design by a threaded member 24 having a bore 26. The injector nozzle preferably is of the type shown in my copending application Serial No. 383,538, filed October 1, 1953, now Patent No. 2,809,868.

Intake passages 28 are also provided with a one-way valve consisting of a check ball 30 and a biasing spring 32 enclosed by a threaded member 34 having an inlet bore 36. All of the inlet passageways are connected by a common manifold 38 having a passageway 40 connected to a supply of fuel.

The intake passageway 28 and outlet passageway 18 are interconnected by a bellows arrangement 42. Upon expansion, or downward movement of the bellows, a vacuum will be created forcing fuel past check ball 30 into the bellows. The collapse of the bellows will force the fuel out of the bellows to the injector nozzle through passageway 18. Instead of a bellows, a piston and a cylinder arrangement or any other suitable device having a variable capacity can be used although not with the success that is obtained from using the bellows according to the present'invention. The unique cooperation of the particular bellows with the pumping linkage will be explained below.

In Fig. 1 the bellows are shown in the completely collapsed position and are actuated by a wobble plate 44 through an actuating ball 46. The wobble plate 44 has an outer race 48 connected through bearings 50 to the inner race 52. Inner race 52 is connected through linkage 54 to a control race 56. The control race is moved upwardly and downwardly by a throttle 58 connected through a link 60.

A spindle Fixedly mounted to the spindle is an arm 66 which drives the inner race 52 through a link 68 which is con nected to the race 52 and the arm 66 at pivot points 70 and 72 respectively. It will be seen that the pivot point 72 forms a fulcrum point about which the wobble plate 44 rotates in order to actuate the fuel pump bellows.

Referring to Figs. 2 and 3, each bellows 42 consists of a plurality of Belleville washers which are connected at their larger and smaller edges in the manner shown. The connections consist of a case-hardened slipper ring 82 surrounded by a neoprene gasket 84, the whole being clamped to adjacent edges by a retainer band 86 which is crimped around the neoprene gasket. Retainer band 86 clamps the gasket snugly about the marginal portions of the washers to form a seal against fuel leakage.

The uppermost washer of the bellows is clamped in a 3 similar manner to a pump manifold chamber amount 88 which is provided with threads 90 so that it can be screwed into the upper plate 14 of the fuel pump housing.

The lowermost Belleville washer is clamped to a bellows -bottom closure member 92 with the same slipper ring, neoprenegasket and crimped retainer. band arrangement. The bottom closure member 92 is provided" with a recess 94 to receive the actuating ball 46.

The manner of clamping the Belleville washers together as shown in Figs. 2 and 3 of the drawings helps to provide for uniformity of operation. The Belleville washers are actually very small thin frusto conical members. If they were connected at their edges by welding, as is done in other types of bellows, they would lose their uniform characteristics and would distort undesirably. Furthenthe comparatively rigid connection at the edges would cause unnatural bending stresses to occur during the operation of the bellows which would tend to cause failure in the bellows by fatigue.

In order to eliminate these disadvantages and to permit the bellows to retain their uniform characteristics, the clamping arrangement as shown is provided. This clamping arrangement permits a freedom of movement between adjacent washers and eliminates the necessity of welding the washers together.

When the bellows is expanded and collapsed,.a very minute movement occurs at the edges of the Belleville washer. Therefore, the case hardened ring 32 is provided to engage the outer and inner edges of the washers to permit that relative movement to occur without wearing out any of the clamping members.

The internal surafce of the bellows mayhave a coating 96 of neoprene or other suitable material to help seal the bellows against leakage, and to fill in voids created by the protruding clamping arrangement. With this arrangement, it is possible for the bellows to be almost completely exhausted when in the completely collapsed position shown in Fig. 3 except for the central hole formed by the inner edges of each washer stage. The importance of this feature, particularly at idling speeds, will be demonstrated in connection with the description of the operation of the invention.

It may also be found to be advisable to coat the outside surface of the bellows with a neoprene coating 98. Without the coating 98, a small leak would cause the internal coating to bulge during the intake stroke and diminish the amount of fuel taken in on that stroke. However, with the outer coating any atmospheric air is prevented from leaking through to bulge the internal coating.

Operation In the position shown in Fig. l, the throttle is completely closed and the bellows are completely collapsed, taking the position shown in Fig. 3. Movement of the throttle 58 in a counterclockwise direction moves the end of the wobble plate 44 remote from the fulcrum 72 in a downward direction. The bellows 42 immediately above that free end of the wobble plate is forced by the spring action of the Belleville washers to open. The opening of the bellows creates a vacuum permitting fuel to be forced into the bellows by way of the intake passageway 28.

The spindle 62 is, of course, being rotated through pulley 64 at engine speed. Spindle 62 causes therotation of the arm 66 carrying fulcrum point 72, as well as inner race 52. The rotation of inner race 52 which has been pivoted about fulcrum point 72 causes the tilted wobble plate to actuate all of the bellows 42 consecutively and in synchronism with engine 'speed. Further counterclockwise movement of the throttle arm 58 causes greater tilting of the wobble plate and consequently greater intake and injection of fuel.

It is important to note that all of the bellows are completely collapsed when the throttle 58 is closed. At this position the bellows can handle the minimum amount 4 of 'fuel and, accordingly, the precise quantity of fuel to be forced through the injector nozzles is most easily controlled. This can be best understood by considering fuel pumps of the type shown in applicants copending application Serial No. 383,538, now Patent No. 2,809,868, in which the bellows are greatly expanded at idling speeds. There, at idling speeds, the bellows are handling a rather large quantity of fuel and control for idling is made much more difficult because of the lack of'uniformity in the size and characteristics of the bellows. The effect of this lack of uniformity is proportionately decreased as the bellows handles smaller and smaller quantities of fuel.

In order further to enhance the idling characteristics, the internal coating 96 is provided for the bellows. With this internal coating, the bellows approaches the theoretically perfect condition of a completely exhausted bellows when the bellows is in completely collapsed condition. With this addedjfeatm'e the bellows handles the minimum possible fuel'for operation at idling speeds.

In a general manner, while I have, in the above description, disclosed what I deem to be practical and efficient embodiments of my invention, it should be Well understood that I do not wish to be limited thereto as there might be changes made in the arrangement, disposition and form of the parts without departing from the principle of the present invention as comprehended within the scope of theaccompanying claims.

I claim:

1. A wobble plate linkage for actuating a plurality of fuel-pumping mechanisms centered on a circle comprising, a rotatable spindle,-a wobble plate including an inner race and an outer race, bearings connecting said inner and outer races, said wobble plate being concentric with said spindle, means connecting said wobble plate to actuate the fuel pumping mechanisms, a control race mounted for rotation about said spindle and for movement in an axial direction, control linkage connecting said control race to the inner race of said wobble plate, fulcrum linkage fixedly mounted to said spindle and connected to said inner race at a location remote from the connection between said inner race and control linkage, said fulcrum linkage forming a fulcrum point for said wobble plate located on a projection of said circle parallel to said spindle, and means for moving said control race in an axial direction.

2. In a fuel pump havinga plate provided with intake and outlet passageways, and a wobble plate actuating arrangement, a bellows construction comprising, a plurality of interconnected stages, each stage comprising two Belleville washers engaging each other at their larger edges, clamping means connecting said larger edges together to permit very small relative movement between said edges and said clamping means, means connecting the smaller edges of adjacent washers of each stage together, means connecting the washer at one end of said bellows to said intake and outlet passageways, and means closing the other end of said bellows, said last named means being adapted to be engaged by said wobble plate and internal coating means for providing a substantially exhausted chamber in said bellows when in collapsed position except for a central hole formed by the smaller edges of the stages.

3. A bellows comprising a plurality of interconnected stages, eachstage comprising two Belleville washers engaging each other at their larger edges, clamping means connecting saidlargeredges of said washers together to permit very small relative movement between said edges andsaid clamping means, said. stages engaging each other at the smaller edges of said washers, inner clamping means connecting said smaller edges together, coating means of a tapering thickness applied to the inner surface of said belows so that the interior of said bellows is free from projections and when in collapsed position is substantially competely exhausted except for a central hole formed'by the smaller edges of said stages.

4. A fuel pump comprising, fuel intake and outlet means, a plurality of bellows connected to said fuel intake and outlet means, each of said bellows comprising a plurality of stages, means on the internal surface of said bellows for providing a substantially completely exhausted chamber in each of said stages when the bellows is in collapsed position, a throttle lever, linkage means connecting said throttle lever with said bellows for maintaining all said bellows fully collapsed when said throttle lever is closed, said linkage comprising a Wobble plate connected to activate said bellows, a spindle, means for rotating said spindle, fulcrum means connecting said spindle to said wobble plate to form a fulcrum for said Wobble plate on a projection of a circle on which the bellows are centered and means connecting the throttle lever to said wobble plate to pivot said plate about said fulcrum.

References Cited in the file of this patent UNITED STATES PATENTS