US3479928A - Diaphragm pump rocker arms - Google Patents

Description

Nmr. 25, 1959 M. NOIROT ET AL 3,479,928

DIAPHRAGM PUMP ROCKER ARMS Filed Dec. 4, 1967 2 Sheets-Sheet 1 ZZZ K/za/ WWI "vi a A Home y Nov. 25, 1969 M. NOIROT E AL 3,479,923

DIAPHRAGM PUMP ROCKER ARMS Filed Dec. 4, 1967 2 Sheets-Sheet 2 INVENTORS '1 ga Attorney 3,479,928 DIAPIRAGM PUMP ROCKER ARMS Michel Noirot, Chelles, and Claude Quatredeniers, Les

lLilas, France, assignors to General Motors Corporation, Detroit, Mich, a corporation of Delaware Filed Dec. 4, 1967, Ser. No. 687,706 Claims priority, application Great Britain, Dec. 6, 1966, 54,527/ 66 Int. (ll. F163 1/10; F04b 43/02; F16h 53/06 US. Cl. 92129 2 Claims ABSTRACT OF THE DISCLOSURE The rocker arm of a diaphragm pump for use as an internal combustion engine fuel pump is made with a metal core one end of which is engageable with a rotary drive cam and the other end of which has moulded integral therewith an arm portion, of nylon or other plastics material, a free end of which is forked for engagement with the pump diaphragm push rod.

This invention relates to diaphragm pump rocker arms and in particular to a rocker arm for a. diaphragm pump of the kind such as is commonly used as a fuel pump for an internal combustion engine.

In such pumps the reciprocatory diaphragm is commonly arranged for actuation by a rocker arm, one end of which engages a rotary cam or like member driven by the engine and the other end of which engages a push rod secured to the centre of the diaphragm.

A diaphragm pump rocker arm according to the invention comprises an elongate metal core one end of which is adapted to be engaged with a cam or other drive mem her and the other end of which has moulded integral therewith an arm portion of plastics material a free end of which is adapted to be engaged with the diaphragm push rod.

The rocker arm has intermediate its ends a transverse bore which forms the journal for a pivot pin on which the rocker arm is mounted in the pump housing.

Intermediate its ends the rocker arm is also formed with a support for one end of a spring by which said one end of the rocker arm is pressed into engagement with the cam or other drive member; the support may either be moulded as an integral part of said arm portion of plastics material, or may be formed as an integral part of said core.

The scope of the invention is defined by the appended claims; and the invention and the method by which it is to be performed are hereinafter particularly described with reference to the accompanying drawings in which:

FIGURE 1 is a perspective view of a diaphragm pump rocker arm the opposite ends of which are respectively engaged with a pump diaphragm push rod and an actuator cam;

FIGURE 2 is an enlarged longitudinal section through part of the rocker arm shown in FIGURE 1;

FIGURE 3 is a section on the line 33 of FIGURE 2; and

FIGURE 4 is a perspective view of a modified form of construction of the rocker arm shown in FIGURE 1.

FIGURES 1 to 3 show a preferred embodiment of the invention in which a rocker arm 1 has a steel core 2, which may be formed as a single part as shown, or may nited States Patent M we be of laminated construction, one end of the core 2 of the arm being formed as a cam follower 3 adapted to engage a rotary cam 4. At its other end the core 2 of the arm has a portion 5 of plastics material, for example, nylon moulded therearound, the free end of the arm portion 5 being forked as shown at 6 to engage about a push rod 7 for the pump diaphragm, and to abut a washer 8 of relatively soft resilient material which overlies a disc 9 of metal secured at the end of the push rod 7.

The other parts of the pump are omitted for the sake of simplicity and as their construction will be well understood by those skilled in the art.

Intermediate its ends the rocker arm 1 has a transverse bore 10 in which can be journalled a pivot pin 13, the bore 10 extending through the plastics portion 5 and the core 2.

A return spring 11 is adapted to press the rocker arm 1 into engagement with the cam 4 and in the embodiment shown in FIGURES 1 to 3 the rocker arm plastics portion 5 is formed with an integral support 12 for one end of the spring 11.

As shown in FIGURES 2 and 3 the core of the rocker arm is formed with an aperture 14 therein intermediate the bore 10 and the forked end 6, to provide an interlock with the plastics material moulded thereon and is also formed with further openings 15 and 16 which are adapted to be engaged by location pins in a mould during the operation of moulding the plastics material about the core.

As shown in FIGURES 2 and 3 the bore 10 is formed in a portion of the plastics material which extends through an opening 17 in the core 2 and projects to either side thereof to form annular shoulders 18, thereby ensuring that there is an adequate surface area to provide a good bearing surface in the bore 10.

As shown in the modified embodiment of the invention illustrated in FIGURE 4, the spring 11 may be mounted on an integral part of the core 2 instead of on a support integral with the plastics portion 5 of the arm. In other respects the construction shown in FIGURE 4 is the same as that shown in FIGURE 1 and the parts thereof bear similar reference numerals.

The forms of construction of the diaphragm pump rocker arm described and illustrated simplify manufacture of the rocker arm and reduce the cost of the tools required for manufacture; the use of such a rocker arm in diaphragm pump results in desirable reduction in the noise of operation thereof.

We claim:

1. In a diaphragm fuel pump having an improved rocker arm comprising a metal core having one end adapted to engage a rotary cam, the other end of said core having an integrally molded arm portion thereon, said molded arm portion extending beyond said metal core to form a free end with said free end adapted to engage a diaphragm push rod on said diaphragm fuel pump, said metal core having a transverse bore wherein said molded arm portion extends through and to each side of the transverse bore in said metal core to form a journal for a pivot pin on which said rocker arm is mounted in said diaphragm fuel pump, support means on said rocker arm in engagement with a spring on said diaphragm pump with said one end of said metal core being pressed into engagement with said rotary cam by said spring.

3 4 a 2. In a diaphragm fuel pump having an improved 3,339,989 9/1967 Kraus 30872 rocker arm as set forth in claim 1, said support means 3,362,250 1/1968 Bradley 74-569 being an integral part of said molded arm portion. 3,186,351 6/1965 Bradley 103-150 References Cited FOREIGN PATENTS UNITED STATES PATENTS 520,903 5/1940 Great Britain.

7/1959 McDufiie 74-569 6/1962 Schmio WILLIAM L. FREEH, Primary Examlner 7/1963 Elfes 103--213 X 12/1958 Katcher 103213 X 10 11/1966 Tucker 308-72 74-569; 103150; 3081

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