US3166835A

US3166835A - Method of manufacture of cast valve rocker arms

Info

Publication number: US3166835A
Application number: US221834A
Authority: US
Inventors: Adelbert E Kolbe
Original assignee: Motors Liquidation Co
Current assignee: Motors Liquidation Co
Priority date: 1962-09-06
Filing date: 1962-09-06
Publication date: 1965-01-26
Anticipated expiration: 1982-01-26

Description

Jan. 26, 1965 KQLBE 3,166,835

METHOD OF MANUFACTURE OF CAST VALVE ROCKER ARMS Filed Sept. 6, 1962 d I INVENTOR.

W BY flawed ewe &5 3 gwam ATTORNE Y United States Patent M 3,166,335 METHUIB GE MANUFATURE 0F CAST VALVE RGCKER ARMS Adelbert E. Kolhe, Eerlriey, Mich, assigncr to General Motors Corporation, Detroit, Mich, a corporation of Delaware Filed Sept. 6, 1962, Ser. No. 221,8-34- 1 illaim. (Cl. 29--414} This invention relates to rocker arms for internal combustion engines and more particularly to an economical method of manufacturing them.

Heretofore, it has been common practice to form such rocker arms individually out of forgings, castings, or sheet metal stampings. The sequence of manufacture of rocker arms was performed such that each forming operation was enacted on each rocker arm individually. Therefore, rocker arms were made one at a time.

It is an object of this invention to provide a method of manufacturing rocker arms in groups whereby certain operations can be made simultaneously on the arms as a group.

In its broadest aspect, the invention provides a method in which a plurality of rocker arms are cast in one work piece and thereafter some of the ensuing finishing operations are performed simultaneously on each connected rocker arm.

In the drawings:

FIGURE 1 is a top view showing the cast work piece consisting of a plurality of rocker arms;

FIGURE 2 is a top view showing the sizing operation in which the bearing surfaces of the connected rocker arms are formed to finished dimension;

FIGURE 3 is a side view of the work piece showing the forming operation in which all valve engaging surfaces and all push rod actuator engaging surfaces of the connected rocker arms are coined to finished dimension; and

FIGURE 4 is a top view showing the final finishing operation in which the individual rocker arms are cut from the parent work piece casting.

Referring now to the drawings, there is shown in FIG- URE l a work piece 10 which is cast in the shape of a plurality of conventionally shaped rocker arms 12 which are integrally connected together at their rocker arm bearing bosses 14. Each rocker arm 12 has the usual valve engaging end 16 and the usual push rod engaging end 18.

The rocker arms 12 of the work piece 10 are cast to size as well as can be done, however, certain areas must be precisely finished. Referring to FIGURE 3, there is shown a forming press having an upper die block 20 and a lower die block 22. The lower die block 22 has a plurality of aligned pins 24 and a plurality of aligned sockets 26. The work piece 10 is placed in the lower die block so that each of the rocker arm ends 18 rests on one of the aligned pins 24, and so that each of the rocker arm ends 16 rests in one of the aligned sockets 26. The upper 3,l6fi,35 Patented Jan. 26, 1965 die block 20 carries projections 28 and 30 which bear on the upper surfaces of the rocker arm ends when the press is closed to thereby coin a finished push rod engaging surface 32 and a finished valve stem engaging surface 34 in each of the connected rocker arms 12.

The Work piece 10 may be cast with an unfinished bore for the rocker arm shaft, or the rocker arm bosses 14 may be cast solid. In either case, it is necessary to size the rocker arm shaft bore and this is done to the connected rocker arms 12 by suitable means, such as a drill 36, as may be seen in FIGURE 2. The drill 36 is advanced through the rocker arm shaft bosses 14 to provide a shaft bearing bore 38. The shaft bearing bore 38 can then be reamed to attain the tolerances and surface conditions required. The finished

surfaces

32 and 34 of the work piece 10 can serve as locating pads to mount the work piece 10 for proper alignment during the drilling and finishing operations such that the shaft bearing 38 in each of the rocker arms is uniform.

Following the drilling operation, any other operations which may be desired, such as drilling oil holes in the rocker arms, can be accomplished in a unified manner on the work piece 10. Following this, the work piece 10 is thereafter cut up into individual rocker arms 12 by means of a saw or milling cutter 40, as shown in FIGURE 4. Only one cutter is shown in FIGURE 4 but it is obvious that a plurality of cutters may be employed if desired to simultaneously separate the work piece 10 into the individual rocker arms 12.

While the invention is described with respect to specific steps of operation and finishing, some variances from that exactly described may be made and still fall within the scope of the claim which follows.

I claim:

A method of manufacturing internal combustion engine rocker arms of the type having a bore for a shaft bearing, a push rod engaging surface offset from said bore, and a valve engaging surface offset from said bore and from said push rod engaging surface comprising the steps of:

casting a work piece in the shape of a plurality of connected rocker arms aligned with respect to the axis of said bore and with said surfaces aligned from end to end of said work piece;

simultaneously coining the push rod engaging and the valve engaging surfaces of the plurality of rocker arms; forming and finishing the shaft bearing bore of said rocker arms by drilling and reaming along said axis;

and subsequently severing each individual rocker arm from the remainder of said rocker arms constituting said work piece.

References Qited in the file of this patent UNITED STATES PATENTS 1,784,866 Fahrenwald Dec. 16, 1930 2,156,692 Hixon May 2, 1939 2,510,091 Dofsen et al. June 6, 1950 2,759,257 Schlegel Aug. 21, 1956