US2041468A

US2041468A - Fuel pump

Info

Publication number: US2041468A
Application number: US753202A
Authority: US
Inventors: Hayward I Grubbs
Original assignee: Individual
Current assignee: Individual
Priority date: 1934-11-15
Filing date: 1934-11-15
Publication date: 1936-05-19
Anticipated expiration: 1953-05-19

Description

May 19, 1936. H, GRUBBS FUEL PUMP Filed Nov. 15, 19:54

IIIIIIII l l V www@ Patented May 19, 1936 ,UNITED STATES .PATENT OFFICE FUEL PUMP Hayward I. Grubbs, El Monte, Calif. Application November 15, 1934, Serial No. '153,202

5 Claims.

- This invention relates to fuel pumps, intended primarily for but, of course, not limited to use upon Diesel engines and has for its object the provision of means whereby the stroke of the pump may be varied to suit conditions. It is also an object of the invention to provide an apparatus which will be silent in operation and which will operate easily and smoothly at all times. It is also an object of the invention to provide simple means for regulating the stroke of the pump. One embodiment of the invention is illustrated in the accompanying drawing and will be hereinafter fully described, the novel features being particularly dened in the appended claims.

In the drawing:

Figure 1 is a vertical section through a fuel pump embodying the invention.

Figure 2 is a horizontal section on the line 2-'2 of Figure 1.

Figure 3 is a vertical section on the. line 3-3 of Figure 1.

In carrying out the present invention, there is provided a casing or fuel chamber I, the sides of which are elongated to provide a crank chamber 2 in which the driving shaft 3 operates, said shaft having a cam 4 thereon which has a straight face and a curved face and which is slightly attened at a point diametrically opposite its high part, as clearly shown, so that the upstroke of the plunger will be sharp, while the downstroke of the plunger will be more or less retarded, thereby avoiding shocks to the mechanism and noise in the operation. Within the casing I is a cylinder 5 delning, with the casing, a chamber 6 containing oil or some other non-compressible fluid. The oil chamber may be provided with a lilling opening at any convenient point, and in the cyllnder, intermediate the ends thereof, are ports 1 'establishing communication between the oill chamber and they interior of the cylinder. A plunger 8 is mounted in the cylinder and rests upon the cam 4 to be operated thereby, and in said plunger 8 is an axial chamber 9 receiving an expansion coiled spring Ill, as shown. Above the port 1, the cylinder is provided with an annular flange II constituting a stop for an upper plunger I2, 'the spring I0 bearing 'at its upper end against the lower endof said upper plunger. Secured toand rising from the upper plunger is -a piston I3 which has its upper end working in a pump cylinder I4 which rises from and is supported by a frame I5 secured to a post or an'ge I6 on the casing I. The pump piston I3 fits snugly but slidably within the cylinder I4 and below the frame I5 carries an abutment or washer II between which and said frame I5 is disposed a buier spring I8. 'I'he pump cylinder I4 has an inlet pipe I9 fitted thereto and in said pipe, immediately adjacent its juncture with the 5 cylinder, is a check valve 20 which will permit flow into the cylinder but prevent ow therefrom. The outlet for the fuel is furnished by the upper end of the cylinder I4 which leads to the cylinder of the engine and in said outlet, immedil0 Y ately above the inlet pipe I9, is a check valve 2| which will permit flow to the outlet but prevent ow therefrom.

Slidably but closely fitted upon the cylinder 5 is a collar 22 which is adapted to cover the ports 15 'I except the lowermost port which lis always open. The ports are so arranged that the port on one side has its top wall alined with the bottom wall of the port on the opposite side, this arrangement obtaining the eiect of a continuous opening or 2o slot. The collar 22 is provided with a tubular offset 23 in which is mounted a check valve 24 which will permit ow into the tubular oiset and the space between the plungers but willl prevent flow therefrom. Pivoted to the collar 22 at dia- 25 metrically opposite points thereof are links 25 which extend upwardly through the top of the oil chamber andare pivoted at their upper ends to a yoke or fork 26 fulcrumed upon a lug 21 on the top ofthe oil chamber. The forkv or yoke 26 30 spans the pump piston I3, as clearly shown, and from its bridge an arm 28 projects over the oil chamber. Journaled in lugs or ears 29 on the top of the oil chamber is a governor rod or shaft 30 which may be connected in any approved manner 35 with .the governor of the engine or may be equipped with means whereby it may be set by hand. Immediately under the arm 28, a crank 3| is formed on or secured to the shaft and bears against the underside of the arm in opposition 40 to a contractile spring 32 which is attached to the free end of the arm and to the wall of the casing I, as shown in Figure 1. To obtain uniformity in the adjustment of the collars upon all the cylinders of a multiple cylinder engine, a set screw 33 is mounted in the arm 28 and bears against the end of the crank 3|, as will be understood. Slight turning of this set screw may be j It is thought the operation will be readily understood from what has been said. On the upstroke of the lower plunger oil in the space between the two plungers will be trapped and the movement of the lower plunger will, therefore,`

be transmitted to the upper plunger so that the pump piston I3 will be raised and any fuel that may be in the cylinder I4 above said piston will be driven past the check valve v'll to the engine cylinder. Upon the downstroke, the weight of the upper plunger I2, together with the expansion of the spring Il, will cause the same to descend and the expansion of the spring I0 will cause the lower plunger to follow the movement of the cam 4 so that it will also be lowered. Upon the downstroke of the piston I3, another charge of fuel will be drawn through the fuel inlet pipe I 9 past the check valve 20 to be driven to the engine cylinder upon the ensuing upstroke of the pump piston. Ii' the controlling collar 22 be set as shown in the drawing so that only the lowermost port 'I is open, the trapping of the oil between the two plungers will occur at the beginning of the upstroke of said plunger so that the upper plunger I2 will be moved at once and its stroke will be approximately the same as the stroke of the lower plunger and a full charge of fuel will be driven to the engine cylinder. Should the engine be idling or running at a very slow speed, the collar 22 will be raised so 'that one or more additional ports 'I will be uncovered and, consequently, as the lower plunger moves upwardly some of the oil above it will be driven out through theAopen ports and trapping will occur at a later point in the stroke so that the stroke of the upper plunger will be relatively shortened and less fuel will be driven into the engine cylinders and at a longer interval. 'I'he feeding ot the fuel may be thus advanced or retarded. The check valve 24, mounted upon the cutoif or regulating collar, serves to break any vacuum that may possibly be formed between the' plungers on the downstroke so that the space between the' plungers will always be illed with oil, although, as Just explained, the trapping of the oil will occur sooner or later in the stroke of the lower plunger according to the adjustment of the collar and, consequently, the stroke of the fuel pump will be varied. The mechanism is compact,

simple and easily manipulated so that it is not apt to get out of order and will operate eiilciently to regulate the stroke of the pump.

Having thus described the invention, what is 'claimed as new is:

1. A device of the class described comprising a chamber to hold a non-compressible fluid, a cylinder in the chamber provided with a. series of ports between its ends to establish communication with the chamber, a lower plunger in the cylinder, means for raising and lowering said plunger, an upper plunger in the cylinder, means for limiting the downstroke of the upper plunger whereby it will be supported above the ports in the cylinder, a cut-off slidably mounted on the cylinder to cover and uncover the ports, a check valve mounted on said cut-off and permitting ow into' the same, and means for adjusting said cut-off, said ports permitting entry of uid between the plungers to establish an hydraulic connection therebetween.

2. A device of the class described comprising a uid containing chamber having an inner cylindrical wall, a series of ports in the inner cylindrical wall of said chamber, said ports being arranged to, in effect, form a continuous opening, upper and lower plungers mounted within the inner cylindrical wall of the uid chamber, an expansion spring between the plungers, means for raising the lower plunger to ride past the ports in the cylindrical wall, a cut-ofi slidably mounted on said wall in the fluid chamber and adapted to cover or uncover said ports, a check valve mounted on said cut-off to admit flow thereinto, and means for vertically adjusting said cut-off, said ports permitting entry of a non-compressible iiuid between the plungers for cooperating with the spring and connecting the plungers.

3. A device oi' the class described comprising a fluid chamber having an inner cylindrical wall and ports in said wall between the upper and lower ends of the same, upper and lower plungers mounted in the cylindrical wall of the chamber, respectively above and below said ports, an operating cam engaging the lower end of the lower plunger, an expansion spring between the plungers, a cut-oil slidably mounted on the cylindrical wall of the fluid chamber and adapted to cover or uncover the ports therein, a pivoted arm on the top of the fluid chamber, links connecting said arm with the cut-olf, and means for setting said arm whereby to adjust the regulating cut-off, said ports permitting entry of a non-compressible iiuid between the plungers for providing an hydraulic connection between said plungers.

4. A device of the class described comprising a fluid chamber, a cylinder extending through said chamber and having ports between its ends, upper and lower plungers working in said cylinder above and below the ports, respectively, means for operating the lower plunger, a regulating cut-olf mounted on the cylinder to ccver or uncover the ports, an arm pivoted on the top of the fluid chamber and extending beyond the same, links connecting said arm with the cut-ofi', a governor shaft journaled on the top of the uid chamber, a crank on said shaft bearing against the underside of the pivoted arm adjacent the free end of the same, and yieldable means connected with the free end of the arm to maintain it in engagement with the crank, said ports permitting entry of carrying amounts of a non-compressible fluid between the plungers for providing a variable hydraulic connection therebetween.

5. A device of the class described including a fluid chamber having a cylindrical wall and ports in said wall, plungers mounted in the chamber respectively above and below said ports, operating means for one of the plungers, tensioning means lbetween the plungers, slidable means mounted on the chamber and adapted for covering or uncovering the ports, means for operating said slidable means, and a set screw for adjusting the last mentioned means, said ports permitting entry of uid between the plungers for providing an hydraulic connection therebetween.

HAYWARD I. GRUBBS. Y