US2338726A - Rocker arm - Google Patents

Description

Jam 11, 1944. M L K 2,338,726

ROCKER ARM F iled Jan. 6, 1942 Patented Jan. 11, 1944 UNITED STATES PATENT OFFICE ROCKER ARM James M. Leake, Monroe, Mich. Application January 6, 1942, Serial No. 425,775

9 Claims.

My invention relates to rocker arms and particularly to the type used to operate Valves in internal combustion engines.

In the advancement and progress of the internal combustion engine, greater engine speedsare being used. As th engine speed is increased, stronger springs are necessary to operate the valves because of the increased inertia of the rocker arm. Stronger springs in turn mean a loss in power of the engine which is not desirable. The only way to avoid the use of stronger valve springs is by the use of a lighter rocker arm. This is Very important in airplane engines where weight is an important factor. The old style of forged rocker arm is very heavy. My former rocker arm disclosed in Patent No. 2,176,083 gives much more strength per unit weight than does the old style of cast or forged rocker arm. My improved rocker arm is so constructed as to give more strength per unit weight than does my former stamped rocker arm, without increasing the cost of manufacture. My improved rocker arm also provides a stronger hub and a better means of lubrication.

One object of my inventionis to provide a rocker arm that readily adapts itself to quantity production.

Another object of my invention is to provide a rocker arm that requires a minimum amount of heat treatment.

Another object of my invention is to provide a rocker arm with a shape that provides a maximum strength for the weight of metal used.

Another object of my invention is to provide a rocker arm made from sheet metal which has greater strength per unit weight than does cast or forged metal.

Another object of my invention is to provide a rocker arm with a hub that provides strength to the rocker arm.

Another object of my invention is to provide a rocker arm with an improved lubricating system.

Another object of my invention is to provide a rocker arm that is simple, strong, durable, and inexpensive.

With these and other objects in View, my invention consists in the construction, combination and arrangement of the various parts of my improved device as described in the specification, claimed in the claims and illustrated in the accompanying drawing.

In the drawing:

' Fig. 1 is a pictorial view of my improved rocker arm without the adjustable contacting bearing.

Fig. 2 is a front elevation of my improved rocker arm with the adjustable contacting bearing in P sition.

Fig. 3 is a top view of my improved rocker arm.

Fig. 4 is a sectional view taken along line 44 of Fig. 2.

Fig. 5 is the right end view of my improved rocker arm shown in Fig. 2.

Fig. 6 is a section taken along line 6-6 of Fig. 2.

Fig. '7 is a view showing the cross sectional Shape along line 1-1 of Fig. 2.

Fig. 8 is a sectional view of the hub of my improved rocker arm taken along line 8-8 of Fig. 3.

Referring now to the drawing in more detail, in Fig. 1 I have shown the stamped or pressed metal arm member ID. This arm member is formed from a flat piece of sheet metal. The sheet metal is pressed into an arm member having two side walls spaced substantially apart and a lower wall joining the side Walls, thus producing a U-shaped cross section as shown in Figs. 6 and '7. One end of the arm is provided with a curved surface I I adapted to act as a contacting bearing. It will be noted that this curved surface II is an integral part of the arm member Ill. The opposite end of the rocker arm member ID is formed into a partial hexagonal hollow prism I2. A hub is formed intermediate the ends of the rocker arm by annular flanges I3 and I4 struck inwardly from the side walls of the arm member III as shown in Fig. 4. A tubular member I5 is placed between the side walls of the arm member Ill before the annular flanges I3 and [4 are struck inwardly. Then as the annular flanges I3 and I I are struck inwardly they are formed firmly against the annular member I5 as shown in Fig. 4. A bushing or bearing I6 is then inserted Within the annular flange portions I3 and I4. A very strong and rigid hub is thus provided by the outer annular or tubular member I5, the annular flanges I3 and I4 and the bushing or bearing I6. The annular flanges I3 and I4 are in reality locked in position by the annular member I5 and the bushing I6. If necessary, these members may be welded, brazed, or hydrogen welded in position, thus forming a still stronger hub.

The annular flanges I3 and I4 do not extend far enough to meet as shown in Fig. 4. Thus an oil passageway I7 is formed between the layers of the outer annular member I5 and the bushing I6. The bushing I6 is provided with an oil hole I8 communicating with the oil passageway I1. The outer annular member I5 is also provided with an oil hole I9 communicating with the oil passageway I], Fig- 8 discloses more clearly how the oil hole l8 and I9 communicate with the oil passageway 11. It is not essential that the oil holes I8 and 19 are directly opposite each other as shown in Fig. 8.

In case that no oil passageway is desired, the annular flanges I3 and [4 can be made to extend inwardly until they touch or abut on the inner ends. If an oil hole is desired in this latter structure, a hole may be drilled throughthe entire. hub after it is assembled.

A nut 20 is fastened in one end of the rocker arm. This nut may be brazed, welded or otherwise secured in the substantially hexagonal prism portion 12 of the rocker arm. An adjustable contacting bearing 2| is provided with a threaded stem 22. The threaded stem is screwed into the nut 28 and is then locked in position by means of the lock nut 23. This arrangement permits the adjusting of the position of the contacting bearing 21 and then retaining it in position after it is adjusted.

Oil from the oil passageway l8 runs down around the hubv and collects in the. oil reservoir 24 below the hub. The lower side of thestamped rocker arm is provided with an outlet 25 so that the oil level. does not get too high in the reservoir. The position of the outlet 25; may be varied in order to obtain different oil levels in the reservoir. A wick 26 leads from the reservoir 24 through holes in the bottom wall of the stamped rocker arm to the contacting bearings II and 2|. This provides lubrication at all times. If this oil reservoir 24. were not provided, the contacting bearings would not be lubricated, when the engine is being started, until the oilpump of the internal combustion would run long enough to pump oil to the rocker arm bearing. With the use of the reservoir 24, the lubrication will not vary due to change of engine speed orchange in temperatures. Thus it will readily be noted that my novel rocker arm provides uniform and positive lubrication at all times.

Fig. 6 discloses the. U-shaped cross section of my novel rocker arm at the line 66 of- Fig. 2. Fig. 7 shows the cross sectional shape along line 'l'l of Fig. 2. It will. readily be noted that the cross sectional area or shape ofmy improved rocker arm is substantially U-shaped at any point. Thus it will be seen in my novel construction of the rocker arm the material is located awayfrom the center line. This type of construction provides for the greatest possible strength for the same cross sectional area or the same amount of material. For example, a hollow tube isstronger than a solidrod of the same cross sectional area. Likewise, an I-beam is stronger than a round or square bar of the same cross sectional area. Furthermore, my novel rocker arm is made from sheet metal which has more strength per unit weight than does cast or forged metal. My rocker arm alsov provides a hub that is very rigid. The hub also joins the two sidewalls of my novel rocker arm thus increasing the rigidity and strength of the side walls.

Since my rocker arm is made from the typeof metal that has the greater strength and also provides. a shape that gives maximum strength for the material used, it will readilybe seen that my novel rocker arm gives the greatest strength and dependability for its weight.

At the present timetractor engines, tank eng-ines, airplane. engines and many.- otherarmy,

navy and industrial engines arebeing speeded up.

in order to. obtain greater speed and more power.

Experiments have shown that when the present internal combustion engine is speeded up heavier valve springs must be used in order that the valves operate properly. When my novel rocker arm was used at the increased speed, the engine operated very satisfactorily with the original valve springs which are lighter in weight. My improved rocker arm has also proven to cause less engine wear and consequently longer life of the engine. This is due to the fact that my novel rocker arm is lighter and hence the inertia of the oscillating rocker arm is less. Also, the weaker and lighter weight valve springs that can be used with my improved rocker arm, create less pressur which results in less wear of the parts involved.

While I have described the details of one form of my invention, I do not wish to be limited to the particular form shown and described as it will be apparent that many modifications therein may be made without departing from the scope of my invention as set forth in the appended claims.

Having thus described my invention, what I claimisz' 1. A rocker arm comprising; a unitary sheet metal arm member of U-shaped cross section; a hub intermediate the ends of said arm member comprising, an annular ring, annular flanges struck inwardly from the vertical walls of said arm member and pressed into engagement with said annular ring and a bushing fastened within said annular flanges.

2. A rocker arm comprising a troughlike sheet metal arm member having parallel sides and a hub intermediate the ends of said troughlike arm member, said hub comprising a plurality of tubular members and annular flanges integral with comprising a tubular shaped member, a bushing and annular flanges struck inwardly from the vertical walls or said arm member and interposed between said tubular shaped member and: said bushing.

5. A rocker arm comprising; a sheetmetal arm member of substantially U-shaped cross section a hub intermediate the ends of said arm member comprising a tubular shaped member, a bushing and annular flanges struck inwardly from the vertical walls of said arm member and interposed b w en aid ubul r shap er a d. a d bushing; an Oil reservoir; an oil passageway communicating with a source. f oil supply and extending to the outer surface of said hub for; feeding oil to, said: reservoir; and a means for. conr ll ng, the l. lev n, sai es r ir A. ampe ocker r mp s ng; a sheet. m ta arm mem er Of; Sub tan al y ubape cr ss. sectio a, hub, om is n an u ar flan es: struck inwardly from the vertical side walls of; said sheet metal arm member, a tubule memhe and. a bushi sa d annular flange bein er osed b tween-said. tubular. member andsaid.

bus ing; anal-.1; eser oir; said sheetme al a m member, an oil passageway extending through said hub for feeding oil to said oil reservoir and a means for controlling the oil level in said reservoir at a predetermined position.

7. A rocker arm comprising a troughlike sheet metal arm member having parallel sides and a hub intermediate its ends, said hub comprising a plurality of tubular members and a plurality of annular flanges extending from said parallel sides, said annular flanges being interposed between said tubular members.

8. A rocker arm comprising a troughlike sheet metal arm member having parallel side walls; a hub intermediate the end of said arm member, said hub comprising a plurality of tubular members and a plurality of annular flanges integral with and extending inwardly from said side walls, said annular flanges being interposed between said tubular members; an oil reservoir in said sheet metal arm member; an oil passageway ex- 20 tending through said hub for feeding oil to said oil reservoir; an oil passageway for controlling the oil level in said reservoir; and means for feeding oil to a surface Without said sheet metal arm member.

9. A rocker arm comprising; a unitary sheet metal arm member of U-shaped cross section; a hub intermediate the ends of said arm member, i hub p i a tubular member, an annular bushing, and a plurality of annular flanges integral with said arm member extending inwardly axially, said annular flanges interposed between said tubular member and said bushing; an oil reservoir in said arm member; an oil passageway in said hub for feeding oil to said reservoir; a passageway for controlling the oil level in said oil reservoir; and a means for providing lubrication to a surface without said arm member.

JAMES M. LEAKE.

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