US1882988A - Fuel pumping device - Google Patents

Description

Oct. 18, 1932. w. H. SCHULZE FUEL PUMPING DEVICE Filed April 14, 1928 Patented Oct. 18, 1932 UNITED STATES PATENT OFFICE wnLLIAII a. scam, or cIIIcAeo, IL InoI's, ASSIGNOB ro s'rnwanr-wannnn conro RATION, or CHICAGO, ILLINOIS, .ACORI'ORA'IION or VIRGINIA 'FUEL ru'urme DEVICE Application filed April 14, 1928. Serial No. 269,947.

The purpose of this invention is to provide an improved construction of a pumping device for supplying fuel to the carbureter of an internal combustion engine from a source 5 of fuel at a lower levelin the carbureter, such pumping device to be actuated by connection with the moving part of' the engine. It

consists in theelements and features of construction shown and described as indicated in the claims. In the drawing Figure 1 is a diagrammatic view for the purpose of showing a-pumpin device embodying the invention in its re ation to the engine and to the fuel source of a motor vehicle.

Figure 2 is an axial. section of the pumping device.

Figure 3 is a detail section of a portion of 12 the structure seen in Figure 2 showing a: detail modification in respect to the cam-engaging terminal of the pumping device.

i In the drawing the'engineis indicated at A, the fuel source at B, and the pumping del 35 vice in its entirety in-Figurel by C. Re-

ferring toFigure 2, is a cam on a rotating shaft' of the engine which is utilized for actuating the pumping device. The pumpingdevice as shown comprises two casing memhere, 21 and 22, formed with mated cavity:

- encompassing faces at which they are mount-.

ed one u on the other for clamping between them a exible diaphragm, 23, WhlCh partitions from the cavity'24, in the face of the casing member, 21, a chamber formed by a cavity, 25, inethe face of the casing member,

22, said chamber, 25, constituting the pumping chamber of which the diaphragm, 23, forms a movable wall by whose movement the cavity of the chamber is enlarged and reduced. To the diaphragm, 23, at the center thereof, there is attached a stem member, 30, having a reduced and threaded nipple, 31, formin a shoulder, 32; and a nut, '34, is screwe onto the threadedjnipple and serves for clamping the diaphragm-Qto the stem member, 30, and for clamping the, central area of the diaphragm between two sheet metal disks, 35, 35, limiting the flexibility of 9 the diaphragm tothe annular portion outside said central area and between the latter and the marginal portion of the diaphragm which is clamped as described, between the 22. y I v The pumping chamber has passages communicating in any convenient manner with the fuel source and with the carbureter, as

' the pipe, 26, leading from the fuel source, and the pipe, 27, leading to the carbureter; and said passages are'controlled by check valves indicated respectively at 28 and 29, opening respectively for-flow into and out of'the pumping chamber, and thereby from the fuel source toward the carbureter, and seating against reverse flow; and it will be understood that the alternate movement of the diaphragm in opposite directions, first mated faces of the casing members, 21 and i fuel movement so as to cause it to move alternately in the opposite direction through the same space in the operation of the pumping device, because such reversal operates for turbulence, 'or with churning effect u on the fuel, tending tointerfere with the uni ormity of iuantityof liquid. fuel fed by a given stro e of the pumping member; and to avoid such reversal, in.the construction shown it will be noticed that the pumping chamber and its inflow and outflow passages and valves are relatively arranged for movement of the :fuel in a continuous substantially ver- I tical direction from the inflow valve into thepumping chamber at the lower side thereof and through the pumping chamber and out at the: upper side to the outflow valve, avoidng moving" it out of the chamber through the same port through which it came in.

a second member, 40,, comprising a cam-ens gaging terminal and wear piece, 41, which protrudes from the body' of the casing member, 21, through a stem, 21?, with which the casing member is provided for the purpose of intruding into the engine casing, and a coil spring, 42, encompassing the stem memher, 40, within thecas-ing reacts at one end against the casing member through the medlum of a bushing, 21", which afi'ords slide bearing for the cam-engaging terminal and wear piece, 41, of the stem member, 4 said spring reacting at the opposite end against a shoulder, 40", formed by reducing the said stem member, 40, to form an annular chamber to accommodate said spring, 42. The terminal and wear piece, 41, of the stem member, 40, has a terminal hook, 41 for spanning the operating cam, 20, and shown as actuated by the eccentric protuberance of the cam encountering the inner side of the hook terminal, and thereby operating to draw the 7 stem outwardly from the casing terminal member, 21. Theend of the stem member, 40, into which the terminal and wear piece, 41, is screwed, is bored to a depth considerably more than that occupied by the threaded engagement of said terminal and wear piece, and before said terminal and wear piece is screwed into place, the stem member, 80, having a head, 30 inserted through the axial hereof the member, 40, said head, 30*, being stopped at the bottom of the bore into which the terminal and wear piece, 41, is screwed.

The opposite end of the stem member, 40, is counterbored to form a shoulder, 40", constituting a stop for the end of a coil spring, 45, which is coiled around the stem, 30, reacting at the opposite end upon the diaphragm, 23, for stressing the diaphragm in the directionfor reducing the capacity of the pump ing chamber.

Upon considering this construction it will be noted that the actionof the cam, 20, upon the stem member which is positively actuated by it, is. in the direction of the pumpingchamber-enlarging movement; and that the positively actuated stem member, 40, is telescoped outside the diaphragm-connected stem member, 30.= And it will'be noted that the spring, 45, which reacts upon the diaphragm, reacts in the direction for reducing the pumping chamber, that is, in the direction for feeding fuel to the carbureter, and reacts for holding the diaphragm at the limit of its stroke in that direction b the force stored in the spring by compression to which it is subjected in the assembling of the parts. And at rest position of the parts, the spring reacts for holding the diaphragm at the limit of its stroke in fuel feeding direction, by the force stored in said spring by the compression to which it is subjected in the original assembling of the parts. And inactive operation this spring may be said to react for transmitting to the diaphragm the thrust of the stem member, 41, due to the reaction of the spring, 42; but it will be observed that in this transmission the spring, v45, operates by,

stroke after the compression and yielding begins corresponds to fuel delivery. And the reaction of the spring, 42, for thrusting the stem member, 40, in the direction of the feeding stroke operates for giving the pumping member its feeding stroke only so far as the spring, 45, transmits the thrust unyieldin ly; or, as it might be otherwise stated, on y in the sense that thrust movement of the stem member, 40, operates to release the stem member, 30, from being held by the flange, 40?, of the stem member, 40, against the reaction of the spring 45, between the diaphragm and said flange, 40 tending to thrust the diaphragm in fuel feeding direction.

Accordingly at the limit of any feeding movement which is actually transmitted to the fuel in the usual installation, the force by which the fuel is fed to,the carbureter is substantially predetermined by the conditioning for reaction of the spring, 45, effected in the original assemblage of the pump structure, and is therefore at all times substantially independent of any variations in the action of the engine or any other source of positive actuation of the pumping device. in view of the variation in respect to fuel lift in the case of an engine on a motor vehicle travelling the highway, due to varying grade on which the vehicle travels, it will be recognized that the springs, 42 and 45 will be conditioned for reaction with adequate force for feeding the maximum fuel lift on the maximum grade, the spring, 45, being stiif enough to transmit the necessary pressure for the maximum lift, and the spring, 42, being enough stronger than the spring 45, to compress the latter in following the cam in the idle phase of the cam cycle to the varying degree necessary, when at the instant of or in the course of the feeding stroke the fuel line to the engine is full, and no fuel movement can be caused by the feeding stroke of the diaphragm. And upon revolution it will be noticed that since the degree of pressure which can be transmitted to the diaphragm,

will be limited to the stifiness of the s ring, 45, according to the conditioning that spring in the ori' al assembling of the pump, any dangeifii overstraining thefuel delivery line or the connectionsof that lineto the 'carbureter by excessive strength of the spring, 42, is avoided by properly limiting the stiflness of the spring, I

In Figure 3 there is shown a slight modification in respect to the form of the positively actuated stem member, said modification consisting in making said stem member in one piece except as to the cam-engaging hook terminal, said one piece, 141, extending entirely through the casing terminal, 121, and axially bored to the end for accommodating the telescoping head, 130", of the memher, 130, the cam-engaging hook being'applied outside thecasing, the end of the stem, 141*, being reduced and threaded, as seen at 141, and the hook member, 141, having a threaded aperture, seen at147, for screwing it into the threaded end of the stem where it is secured in position by a jam nut, 148.- In this form the bushing, 121", corresponding to the bushing, 21", of Figure 2, is formed with an interior projecting key rib,

121, which engages a key way, 141, cut in' the side of the stem member, 141, for ensur- .r ing against any turning of the stem member,

141, in its slide hearing, which would dis-.

' place the cam engaging part, 141, with respect to the cam, 120.

This function is performedin the construction of, Figure 2-by providing the cam, 20, with a peripheral groove, 20, forming a key way and furnishing the member, 41,

way.

I claim 1 r 1. A fuel feeding device comprising a housing containing a pumping chamber and passages connected for inflow from a fuel source and outflow toward the carbureter of the en ine served, with me-way seating valves in said passagesopening for flowtoward the carbureter and seating against reverse flow, the pumping chamber having a movable wall mem r y by whos'e "opposite movements the chamber capacity 'is enlarged and reduced; means for moving said pumping It other for extending and reducing the stem,

"with a key projection, 41",, engaging the key osed to positive actua-" the chamber-enlarging" direction, and a sec-, ond spring weaker than the first reactin g on.

the first mentioned stem memberand said movable wall member fortransmitting movement of said second mentioned stem member to said wall member in chamber-reducing direction.

2. A liquid pumping'device comprising a housing containing a pumping chamber with inflow and outflow passages and valves controlling one-way flow of the liquid pumped, the pumping chamber having a movable .wall member by whose movement in opposite directions the chamber capacity is enlarged and reduced; means for moving said movable wall member in said opposite directions consisting of a two-membered stem of which the first member is secured to the movable wall member for-positively moving therewith and the second is exposed to positive actuation in the direction of the chamber-enlarging movement of said movable wall member; a

sprin reacting between the casing and the se'con stem member to retract said second stem member in the direction of the chamber-reducing movement of said movable wall member, the two stem members being movable relatively to each other for extending andreducing the operative length of the limiting said extension and adapted at said limit to be engaged with each other by said stops for effecting longitudinal movement of ;said first stem member in chamber-enlarging total stem and having cooperating stops direction, and a second spring reacting at one end on the second stem member and at the opposite end on the movable wall member, and thereby on the first stem member for holding \the stops separably engaged with eachiother. X Y

3. A fuel pump'for' internal combustion en 'nescomprisin a pump casing, a movab e pumping mem r sulpporte'dby said casing and cooperating wit a pumping chamber' within said casingfor-intake and discharge of fuel, a reci'procable operating mem-,

her having a constantstroke and connected .-with said pumping member with provision for lost motion, means for positively moving said, operating memberjn one direction for transmitting a sitive suction stroke to said pump mem r, said lost motion connection acting positively when the operating its suction stroke, resilient means for returning said member, and additional resilient means interposed between said member and said pumping member for limiting the discharge impulse and permitting a variable dis charge stroke. p v

4. A fuel pump for internal combustion member moves to give the pumping member engines comprising a pump casing adapted to be mounted on an engine casing adjacent an aperture thereof, a reciprocable pumping member: within said casing adapted to cooperate with a pumping chamber therein, an operating stem secured to said pumping mem: ber, a second operating stem associated with said first stem with provision for lost motion, said stems having cooperating stops for limiting'rclative movement in one direction, en-

gine-driven means for positively moving said second stem in a direction to transmlt a positive suction stroke to said pumping member through said first stem, resilient means reacting bet-ween said stems to normally hold said stems in stopped relation for. movement as a unit, additional resilient means reacting up on said second stem to transmit a discharge movement to said pumping member and said first stem by acting through said first mentioned resilient means, said additional re-' slhent means having an effective force capable of overcoming said first-mentioned resilient means and adapted to be conditioned for reaction by the positive suction stroke of said pumping member.

5. A pumping apparatus for supplying fuel comprising a reciprocable pumping member, a stem secured to said pumping memher, a sleeve shdable relative to said stem, 00-

operating abutments on said stem and sleeve for limiting movement in one direction means for actuating the sleeve in one direction to transmit the "positive suction stroke to said pumping member through said stem] and abutment, resilient means reacting between said stem and sleeve to 'hold said abutment in engagement and preventing relative movement, and additional resilient means for producing movement of said sleeve in a dis charge direction and having an effective force capable ofovercoming said first named resilient means, whereby the movement of said sleeve is yieldingly transmitted through said first. named resilient means to said pumping member for permitting a variable dis-. charge stroke.

In testimony whereofil have hereunto set my hand at Chicago, Illinois, this 31 day of March, 19:28. a

WELIAM H. SCHULZE.

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