Rocker arm for internal combustion engines

Dec. 31, 1968 kazuo hirose 3,418,985

ROCKER ARM FOR INTERNAL COMBUSTION ENGINES Filed Sept. 1, 1967

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Applicant

KAZUO HIROSE

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United States Patent Office „ . ^{3 418 985}

Patented Dec. 31, 1968

3,418,985 ROCKER ARM FOR INTERNAL COMBUSTION ENGINES

Kazuo Hirose, 9 Tajima, Urawa-shi, Saitama-ken, Japan Filed Sept. 1, 1967, Ser. No. 665,705 1 Claim. (Cl. 123—90)

ABSTRACT OF THE DISCLOSURE

A valve rocker arm for internal combustion engines formed from a single stamped sheet of metal having a base of a uniform arc from end to end with a pair of parallel side walls extending upwardly from one end of the base, and having bearing apertures formed in the side walls adjacent the apogee of the arc of the side walls, with a threaded receiving bore formed in the base extension of the side walls.

This invention relates to a valve rocker arm for internal combustion engines and more particularly to a valve rocker arm employed in the overhead valve type of internal combustion engines.

One of the primary objects of the present invention is to provide an improved valve rocker arm which is economical to manufacture.

Another object of the present invention is to provide a valve rocker arm that is light in weight, durable and inexpensive.

The improvide valve rocker arm according to the present invention is made from single sheet metal or strap metal by means of stamping process.

Therefore, another object of the present invention is to provide an improved, simplified valve rocker arm of generally flat appearance, having sufficient strength and mechanical rigidity.

This improved valve rocker arm relating to the present invention comprises a channel like portion at the midway of the arm to provide a pair of bearing apertures on the flanges of the channel portion to support the arm on a rocker shaft pivotably, and the both ends of the bottom wall of channel elongated flatly to be employed as contacting bearings for the valve stem and the tappet rod of the engine respectively.

Another object of the present invention is to provide a valve rocker arm with flat cross-sectional construction, except for channel like portions, formed from sheet material by means of simple process of stamping.

This improved valve rocker arm combines the advantages that are adequate when employed in the present day high speed internal combustion engines as it has the attributes of strength and little weight comparatively.

Especially with the higher speed engines, it is very essential that the weight of the oscillating rocker arm be reduced to a minimum without any reduced strength. In the high speed engines the weight factor is very important because it directly affects the useful output power of the engines.

Therefore another object of the present invention resides in the provision of a valve rocker arm made from sheet metal by means of pressing to be shaped flatly, simply, and light without reduced mechanical strength characteristics.

It is also important that the simplified structure and the decrease in weight be accomplished with reducing the cost, and be able to adapt this rocker arm for mass-production, enabling manufacture at a very reasonable cost.

Accordingly, this improved valve rocker arm of the present invention requires a minimum amount of skilled assistance to manufacture and is especially adapted to the small cylindered high speed engines.

Other objects and features of novelty of this invention will be either specifically pointed out or will become apparent when referring, for a better understanding of the invention, to the following description taken in conjunction with the accompanying drawing, wherein:

³ FIG. 1 is an elevational blank form of one embodiment of the valve rocker arm comprising the present invention as constructed;

FIG. 2 is a perspective view of a completed rocker arm of FIG. 1;

lo FIG. 3 is a side elevational view of the rocker arm of FIG. 2;

FIG. 4 is a bottom view of the rocker arm of FIG. 2;

FIG. 5 is a perspective view of the other embodiment according to the invention which is adequate to be ap15 plied for a larger cylindered high speed internal combustion engine; and

FIG. 6 is a perspective flow chart illustrating a process for the embodiment shown in FIGURES 1 to 4 of the invention.

Referring to the drawing, wherein like reference numerals designate similar portions throughout the various views, in FIG. 2 is shown the completed rocker arm 10 which is embodied for an example according to the present invention by means of stamped or pressed metal blank

10 . This metal blank 10' is pressed or stamped from a flat piece of sheet metal material. The sheet metal Hank 10' is pressed into an arm body 10, as shown in FIG. 2, having a pair of vertical side walls 11, 11 including a pair of bearing apertures 15, 15 spaced substantially apart and bottom wall 12 joining said side walls and forming Ushaped cross-sectional channel portion integral as shown in FIG. 4. The both ends of the arm are elongated outwardly and provided contacting bearings 13, 14 with the bottom wall 12 integral. The arm member 10 including said beatings is bent downwardly at midway in desirous degrees, and a screw threaded bearing hole 16 is provided at the center of said bearing portion 14 at one end of the arm to employ for fastening an adjustable screw. The opposite end of the arm member 10 is formed into a flatly curved portion 13 adapted to act as a contact bearing for a valve stem of an internal combustion engine. It will be noted that the flattened portion 13 is an integral part of the bottom wall 12 of the arm 10 and formed wider than the bearing end of 14. At least the lower surface of said flattened portion 13 will be hardened to resist wear.

In the modification of the improved valve rocker arm of this invention 10 illustrated by FIG. 5, vertical side walls 11, 11 are elongated along both sides of the body rn ^{10 an end and} provided channel cross-sectional con⁰ tacting bearing to accommodate for a larger cylindered high speed internal combustion engine.

It is apparent the modified rocker arm 10 as shown in FIG. 5 finds great utility when applied to the voluminous high speed engine since it may improve these mechanical characteristics itself for the first mentioned embodiment comparatively.

Any embodiments of rocker arm according to the present invention will be manufactured by a simplified manner θθ of process illustrated as follows.

Referring to FIG. 6, in practising the preferred process of making valve rocker arms contemplated by this invention, first a piece of sheet metal, preferably sheet steel, is pressed out of a blank to desired form for use as rocker ₆₅ arm member 10', for instance in the form shown in FIG.

1, having a pair of round ear portions 11', 11' at intermediate both sides of the member 10', and a pair of end portions 13', 14' provided integral with the bottom portion 12 of the member. Also, in this step, a pair of aper70 tures 15, 15 may be punched in said ear portions 11', 11' and hole 16 in one end 14' simultaneously. (See FIG. 6-1.)

3,418,

Second, the punched blank 10' is bent by means of stamping dies comprising lower cavity member L to adapt said blank and upper plug member U so as to bend the arm body and the ear portions as shown in FIG. 6—II. Thus, the arm member 10 is shaped into desired form, 5 that having a channel portion at the middle portion of said member, in this second step.

In third step, a reamer C cuts through into the hole 16 of the end portion 14 and to a pair of apertures 15, 15 punched in the side walls of the member 10, the deformation of said apertures are so eliminated as to be adapted to receive a rocker shaft of an engine through said apertures smoothly. After cutting the hole 16 with the reamer a screw thread is provided on the inside of said hole by means of a tapping machine as to be screwed an adjustable 15 contacting bearing into the hole. Any necessary facing process including burring, polishing and other machining practises may be finished in this third step. (See FIG.

6—III.)

In next step of process, the finished elements of valve 20 rocker arms 10 are dipped into thermo-treating salt bath S so a hardened surface is so provided on the rocker arm as to protect wear. (See FIG. 6-IV.)

The cyanide process and sulfur treating process may be applied as the above mentioned treating. 25

As shown in FIG. 6-V, finished rocker arm 10 with hardening treatment of the salt bath is assembled by provision of an adjustable contacting bearing 17 screwed into the hole 16 until the desired position is reached. The adjustable contacting bearing is then tightened by means of 30 the lock nut 18 in desired position.

While two embodiments of the valve rocker arm for internal combustion engines have been specifically described, it is to be understood that the particular forms shown

985 only and it will be apparent that many modifications therein may be made without departing from the scope of this invention as set forth in the appended claim.