US1871040A - Pump - Google Patents

Description

Aug. 9, 1932. w. c. CARTER PUMP Filed April 29, 1929 i /N VEA/roe.-

5y l @Trae/w96 Patented Aug. 9, 1932 y UNITED STA Tus' PATENT OFFICE Application mea April as,

This invention relates to pumps of the kind that are used in fuel supply systems for-in,- ternal combustion -engines for drawin liquid fuel from a source of supply and delivering it to the carburetor of the engine, and particularly, to fuel pumps of the type in which the pumping element consists of as sealed, frictionless, vibrating member like .a diaphragm, andthe operating mechanism for the pumping element consists .of a cam or other mechanically-actuated device driven or operated by the engine and having a fixed or definite path of movement.

The object of my invention is to provide a reliable diaphragm pump for fuelsupply systems, that is inexpensive to manufacture and of such design lthat the operating mechandism for the diaphragm will not wear rapi ly.

Figure 1 of the drawing is a vertical sectional view of a. pump embodying my present invention.

Figure 2 is a side/elevational view of said pump, partly broken away, so as to illustrate the valves of the pump; and

Figure 3 Ais a fragmentary vertical sectional view, similar to Figure 1, showing the pumping element at the end of its suction stroke.

My improved pumpis intended to be used primarily for drawing'liquid fuel from a ,supply tank and delivering said fuel to a reservoir or to the ioat chamber of the carburetor associated with the internal combustion engine that drives the cam or other me- 'chanically-actuated device that constitutes part of `the'mechanism for operating the -pumping element of the pump. In the accompanying drawing which illustrates the preferred form` of my invention, A- designates the pumping element which consists of a diaphragm or similar vibrating member that seals one side of the pumping chamber and which operates without producing friction. Said diaphragm maybe composedeither -of one or a plurality of layers of fabric treated with a substance that will render the fabric impervious-to gasoline orwater without making it brittle or inflexible, and said diav phragm is arranged so that it forms one wall 1929. serial Na. 359,699.

of a pumping chamber l intowhieh liquid fuel is drawn when said diaphragm lexes .in one direction and from which liquidfuel -is forced when said diaphragm is flexed. in the opposite direction. The pump is provided with'a spring-pressed inlet valve 2 that opens automatically and admits the liquid to the chamber l of the pump during the suction stroke of the diaphragm A, and it is also provided with a discharge valve 3 that opens automatically and permits the liquid to escape from said pumping chamber during the discharge stroke ofthe diaphragm.v Any i suitable type or kind of inlet valve and discharge valve may be used, and the pump can either be equipped withvan inlet pipe that leads directly. to the inlet valve, or it can be equipped with a bowl or reservoir B to which the-liquid is admitted by a supply pipe and from which the liquid thereafter escapes into the chamber 1 of the pump through the passageway controlled by the inlet valve. In the form of my invention herein illustrated the pump is provided with a bowl B that is detachably connected to the body portion C of the pump and arranged so that the interiorl Yof same communicates with an inlet passage way in said body ortion in which the inlet valve'2 is arrange liquid being supplied to the bowl B `by aV supply pipe 4 attached to the body portion Cof the pump and arranged so as to dischargedownwardly into the bowl B, as shown in Figure 1. The pump is provided with a discharge pipe 5 that leads from the passageway controlled by the 'discharge valve 3 to a reservoir or carburetor lioatl chamber `(not shown) inj which a certain approximate fuel level is maintained by a def vice that controls a valve arrangedbetween i the discharge pipe 5 of the pump and the apparatus to which the pump is delivering fuel. When said apparatus contains its maximum quantity or supply of fuel, the valve interposed between said apparatus and the discharge pipe 5 of the .pump remains closed or seated, thereby functloning as an obstruction or cut-offdevice for yth e discharge pipe 5 of thepump. p v` #l The diaphragm A is disk-shapedI and is arranged vertically at one side of a cavity in the body portion C of the pump that constitutes the pumping chamber 1. The peripheral portion of said diaphragm is clamped between anzannular part 6 on the body portion C, and a co-operating housing member 7 having an open-ended tubular guide portion that projects inwardly through an opening in the crank case D of the engine with which the pump is used, as shown in Figure 1. Said housing member 7 preferably consists of a sheet metal stamping and the tubular guideportion of said member has a diameter substantially the same as the diameter of the effective porti-on of the. diaphragm.

The operating mechanism for the diaphragm comprises a cam E or other mechanically-actuated part operated by the engine,

the diaphragm causing liquid to be expelled from the chamber 1 and forced through the discharge pipe 5, or causing apressure to be created in said discharge pipe, depending upon whether or not the valve interposed between said discharge pipe and the apparatus to which the pump is deliver-ing fuel is capable of opening or is held in its seated or closed condition, due tothe apparatus containing .itsmaximum quantity of liquid. The means just referred to that is preferably interposed between the cam E and the diaphragm A is constructed in such a manner that if the flow of liquid through the discharge pipe 5 leading from the pump is obstructed, said means will yield suliciently to preventthe thrust of the cam E from being exerted on the diaphragm, thereby causing the diaphragm A to remain at rest or in a quiescent state while the cam E continues in operation. Said means is preferably composed of a relatively stiff spring 8, of greater force or strength than the spring F, combined with two members 9 and 10y in such a way as to form in effect a lunefer. thrust member or ram. which under certain conditions, will transmit movement from the cam E to the diaphragm A, but which, under different conditions, will yield sutliciently to permit the diaphragm to remain at rest while the cam E continues in motion. In other words, when the apparatus to which the pump is delivering liquid contains less than its maximum supply of liquid, the spring 8 will co-act with the members 9 and 10 to form a ram that transmits movement from the cam E to the diaphragm A,

so as to impart discharge strokes to said diaphragm, thereby causing charges of liquidV to be fed intermittently through the discharge pipe 5 leading from the pump, and when said apparatus contains its maximum quantity of liquid, resulting in closing or seating of the discharge valve 3 of the pump, the spring 8 yields sufliciently to permit the diaphragm to remain at rest While the cam continuesi in motion. v

In order to reduce the cost of manufacture and also produce a pump which is of such de sign that the operating mechanism for the diaphragm will not wear rapidly and will be easy to assemble and combine with the diaphragm, the members 9 and 10 are formed from sheet metal stampings that are arranged in opposed relation with the spring8 interposed between said members, as shown in Figure 1, the member 9 constituting the outer end portion of the plunger and being arranged in sliding engagement with the tubular guide portion of the housing member 7. After the members 9 and 10 and spring have been assembled, a rod 11 is passed through the center of the member 10 and attached to the center 0f the member 9 preferably by upsetting one end of said rod.` The rod 11 is provided at its opposite end with a head or flange 12 which lits in an integral hollow boss 1Ga on the member 10 that projects towards the member 9, and which serves as a guide for the spring 8. The rod 11 is of such length that when the head 0r flange 12 thereon is in contact or in engagement with the end wall of the hollow boss 10a on the member 10, as shown in the drawing, the spring 8 Ywill be maintained under such tension that it will serve as a thrust device for transmitting movement from the cam'E to the diaphragm A, so as to move said diaphragm from the position shown in Figure 3 into theA position shown in Figure 1, thereby imparting a discharge stroke to same that causes the liquid which was drawn into the chamber 1 of the pump during the preceding suction stroke of the diaphragm to be expelled from same past the discharge valve 3 and forced through the discharge pipe 5to the apparatus to which the pump is delivering liquid. If the inlet valve leading to said apparatus is closed, as previously explained, the discharge valve 3 of the pump will remain closed or seated when the eccentric portion of the cam E starts to act onthe member 9, with the result that the spring 8 will yield or compress sufliciently to absorb the motion imparted to the member 9 while the eccentric portion of the cam E is traveling over the same, said spring 8 expanding and returning to its former condition as soon as the eccentric portion of the cam-passes 'out of engagement with the member 9. It ,will thus be seen that under certain conditions, i. e., when'the apparatus to which the pump is delivering liquid contains its maximum quantity of liquid, the diaphragm A of the pump will remain at rest or in a quiescent state, notwithstanding the fact that the cam E or other mechanically-actu ated device of the diaphragm operating mechanism continues .in operation.

In order to permit the rod 11 to move relatively to the member under conditions previously described, without imparting a thrust to the diaphragm, the hollow boss 10a on the member 10 is of such depth or length that the head 12 on the rod 11 can reciprocate therein Without exerting a thrust on the diaphragm when the diaphragm is held in an inactive or idle position, due to obstructing the flow of liquid through the discharge pipe 5 leading from the pump. Preferably, flanged'metal protecting members '13 and 13a are interposed between the diaphragm .and the spring F and between the diaphragm and the member l0, as shown in the drawing,

and the member 13a is so proportioned that the flange at the periphery of same is guided by the housing member 7. The member 9 is constructed in the form of a substantially hollow or cup-shaped piston that slides freely in the tubular guide portion of the housing member 7, and said housing member is open at its outer end so that the lubricating oil in the crank case of the engine can enter the interior ofV said housing, and thus lubricate the portion oflsame in which the member 9 slides. Due to the fact that the member 9 is moved in one direction (inwardly) by a r0- tary cam E which has a wiping action on a wear plate 9a attached to the outer end of the member 9, said wiping action-tends to force the member 9 'downwardly or -laterally against the lower side of the tubular guide portion of the housing 7 in whichf the member 9 slides, assuming that the cam E rotates in anti-clockwise direction. In order to counteract or overcome the tendency of the lower side of the member 9 and the tubular guide portion of the housing 7 to wear rapidly, due to the downward thrust or lateral thrust of the cam E, I arrange .said cam in such relationship with the member 9 that when said cam first comes into contact with theV member 9it tends to cock or tilt said member'9 suiiicientl to counteract. the downward thrust of the cam on the member 9, and thus in effect cause the friction to be distributed substantially uniformly over the contacting surfaces of the member 9 and the tubular guide portion of the housing member 7 in which the member 9 slides. In the form of my invention herein illustrated this highly desirable result is attained by disposing the member. 9

in such relationship with the operating shaft of the cam E that the center of said shaft is scribed is inexpensive to build, itis reliable in operation, and notwithstanding the fact that the operating mechanism 4for the pumping fuel contains the maximum quantity of fuel which said apparatus is capable of holding. 1

Having thus described my invention, what Iclaim as new and desire to secure by Letters Patent is: f

A pump for fuel supply systems provided with a pumping chamber, a diaphragm for creating suction and pressure in said chamber, an open-ended tubular guide projecting* laterally from the body of the pump, a spring on one side of said diaphragm for iexing it in one direction, a reciprocating plunger in said tubular guide a second spring that cooperates with said plunger tofleX the diaphragm inthe opposite direction, and a rotary cam that has a wiping action on the outer end of said plunger, the axis ofsaid cam being disposedV suiiiciently off center with relation to the longitudinal .axis of said plunger to cause the cam to have a tendency to cock or tilt the plunger when it first contacts with same and thus counteract the thrust which the cam exerts on the plunger in a direction tending to force the plunger laterally against the side of the tubular guide in which the plunger reciprocates.

slightly higher than the longitudinal axis v of the member 9. By constructing the operating mechanism for the diaphragm in thls manner I am able to successhilly dispense with a'friction reducing bearing between the cam E and the member 9 which 'it operates.

'A pump of the construction above de- WILL AMC. CARTER,

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