US3483826A - Method of and lever pin assembly in pump - Google Patents

Description

' Dec. 16, 1969 R. w. DAVIS 3,483,826

METHOD OF AND LEVER PIN ASSEMBLY IN PUMP Filed Sept. 5, 1967 INVENTOR ROONEY W. DAWS naw/ ATTORNEY United States Patent 3,483,826 METHOD OF AND LEVER rm ASSEMBLY 1N PUMP Rooney W. Davis, St. Louis, Mo., assignor to ACF Industries, Incorporated, New York, N.Y., a corporation of New Jersey Filed Sept. 5, 1967, Ser. No. 665,591 Int. Cl. F04b 43/02; B23p 19/02; B21d 39/00 US. Cl. 103-150 6 Claims ABSTRACT OF THE DISCLOSURE An automotive diaphragm type fuel pum having a die cast lever arm body is provided with a lever pin which is installed in a pin receiving slot and secured therein by peened over portions of the edge of the slot.

This invention relates to diaphragm type pumps and more particularly to a method of and the assembly of the lever pin in the pump.

Diaphragm type automotive fuel pumps of the general type here involved are exemplified by the one shown and described in the United States Patent No. 2,856,862 granted Oct. 21, 1958 to A. C. Korte. In such a pump a cam driven rocker arm or lever arm is mounted on a pivot pin which is inserted into a drilled hole transverse the body of the pump.

An object of the present invention is to provide an improved method of assembly and structure for installing the pivot pin in the pump body.

It is a further object of the invention to provide a more economical and simplified method for and assembly of a diaphragm type fuel pump.

According to the invention the pump body, which may be of die cast metal, is provided with an aperture for receiving a pump rocker arm in which there is formed into the body a transverse groove for receiving a lever pin and there is further provided adjacent the edges of the groove raised portions which are subsequently flattened by compression or peening to secure the pivot pin and the rocker arm in position.

Further objects, advantages and features will appear from the accompanying drawing, description and the appended claims in which:

FIGURE 1 is an elevation view of a fuel pump having a portion thereof broken away;

FIGURE 2 is an elevation view of the mounting portion of the body with rocker arm and pivot pin in place;

FIGURE 3 is an enlarged view of a portion of the mounting face of FIGURE 2 but less the rocker arm;

FIGURE 4 is an enlarged cross section taken along the lines 4-4 of FIGURE 3 and;

FIGURE 5 is a cross section taken along the lines 55 of FIGURE 3 and;

FIGURE 6 shows another embodiment similar to that of FIGURE 4.

Referring to the drawing there is shown generally at 10 in FIGURE 1 a pump of the diaphragm type. Pump 10 is Provided with a body 12 having an aperture 14 for receiving a rocker arm 16 as shown. The rocker arm is actuated by a cam 18 mounted on a cam shaft 20 which is driven by the internal combustion engine.

A pumping chamber 22 surmounts body 12 and includes a suitable diaphragm, springs and inlet and outlet check valves. Further details of the pumping chamber is substantially similar to that of the Korte Patent 2,856,862 mentioned earlier.

Cam 18 imparts motion to the rocker arm 16 which in turn causes the pump stem 24 to reciprocate. Stem 24 is provided with a head 26. A cushioning member 28 is interposed between head 26 and a bifurcated end 30 of rockice er arm 16. A spring 32 urges rocker arm 16 onto the surface of cam 18 at all times. Rocker arm 16 is pivoted on a pin 40.

FIGURE 2 shows the mounting end of the fuel pump and illustrates the final assembly of the rocker arm pin 40 and the rocker arm 16 in the cavity 14. Pin 40 is recessed below the face 42 of the mounting flange. The recessed portion is shown at 44. Details of the pin mounting and the method of installation are shown in FIGURES 3, 4 and 5.

For clarity the rocker arm has not been shown in FIGURE 3 but it will be understood that the rocker arm would be in place at the time of final assembly. The righthand portion of FIGURE 3 shows the condition of the pin after final assembly while the lefthand portion shows it during an intermediate step in the assembly operation.

Referring to FIGURES 4 and 5 there is shown a slot 50 which receives the pin. The bottom of slot 50 is provided with rounded corners 52 having a radius only slightly greater than that of the pin itself. A lip or bead 54 traverses the length of each of the slots. Slot 50 may have a slight draft as for example approximately 1 degree. Since the entire body portion 12 is conveniently formed by die casting of a suitable metal such as aluminum, zinc or magnesium, the draft just mentioned is of some assistance in the die casting operation. Pin 40 is press-fit into the slot 50. In order to accomplish this, the pin 40 has a diameter slightly greater than the width of the slot 50. In the case of a pin having a nominal diameter of A", the width of the slot will have a dimension of the order of a .003 less than the diameter of the pin. Because of this interference fit, a substantial force is employed to press the pin into the slot. This force may be of the order of approximately one-half ton.

Once the pin 40 has been pressed into the bottom of the slot 50, and of course the rocker arm 16 is in place at this time, the remainder of the final assembly operation is performed.

A peening tool 60 is pressed down against lips 54 with sufficient pressure to cause the metal to flow around the upper surface of the pin 40 to the configuration shown in FIGURE 5. It is not necessary that the entire length of the lip 54 be peened, but a substantial amount of the lip should be peened down in order to retain the pin against outside forces. Usually at least 50% of the length of the lip 54 will be peened in this manner. It has been found convenient to perform the peening operation as a steady force rather than as a hammer blow. When an aluminum die casting is used as the body portion of the pump, and the pin installed as described, pin 40 is held in place so securely that a force of greater than one-half ton is required to pull the pin out of the slot. This again is based on the use of a pin of approximately A" in diameter. Larger pins or smaller pins will have corresponding greater or lesser withdrawal forces.

The shape of the slot or groove 50 can be varied for example as shown in FIGURE 6 where the bottom of the slot is contoured to closely fit the outer diameter of pin 40. Instead of the tapered lip 54 a lip 54A of somewhat rectangular cross section can be utilized. It is important that there be enough metal in the lip to allow for a portion of it to flow around at least a part of the upper surface of the pin.

While the slot 50 has been shown with raised portions or lip 54, 54A, it will be appreciated that the lips could be omitted and a portion of the die casting adjacent the slot peened downwardly to achieve substantially the same result. Also it will be appreciated that the lever pin is held so that it cannot rotate as has been customary in the past. Any attempt to withdraw the pin will usually result in a tearing away of a portion of the body thus making 3 it impractical if not impossible to replace the pin and/ or lever arm. I claim: 1. A method of securing a lever pin in a die cast pump body comprising the steps of: 5

(a) forming said body with an aperture therein and a pin receiving slot transverse said aperture (b) inserting a lever pin of greater diameter than the width of said slot in said slot and producing an interference fit therebetween, and (c) securing said pin in said slot by peening by compression a substantial portion of the edges of said slot to cause flow of metal into said slot and partially over said pin whereby to secure said pin in said slot. 2. The method of claim 1, wherein the said slot is 1 formed with raised portions constituting the said edges.

3. The method of claim 1, in which the step of inserting the lever pin in the said slot includes the step of forcing the pin with sufficient force to overcome an interference fit whereby to seat the said pin firmly in the bottom of the slot.

4. A diaphragm pump having a die cast apertured lever arm body, a slot in said body transverse the said aperture, a lever pin in said slot, the width of the said slot 4 being slightly less than the diameter of said pin and producing an interference fit therebetween, a rocker arm pivoted on said pin, and peened over portions of the edges of said slot, said portions extending a substantial length of said slot thereby retaining said pin in said slot.

5. The pump of claim 4 in which the said edges of the slot constitute raised portions extending substantially the length of said slot.

6. The pump of claim 4 including a draft of approxi- 10 mately one degree in the walls of said slot.

References Cited UNITED STATES PATENTS 1,742,770 1/1930 Kamrath 103l50 1,920,497 8/1933 Clark et al. 29-515 2,017,154 10/1935 Larkin 29-525 1,296,402 3/1919 Kahn 29-5l5 3,141,417 7/1964 Norberg et al 103150 HENRY F. RADUAZO, Primary Examiner us. 01. X.R. 29 515, s25

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