US2435727A

US2435727A - Valve actuating mechanism

Info

Publication number: US2435727A
Application number: US668932A
Authority: US
Inventors: Louis R Spencer
Original assignee: SPENCER AIRCRAFT MOTORS Inc
Current assignee: SPENCER AIRCRAFT MOTORS Inc
Priority date: 1946-05-10
Filing date: 1946-05-10
Publication date: 1948-02-10
Anticipated expiration: 1965-02-10

Description

Feb. 10, 1Q48. 1 R. SPENCER V2,435,727

YLVE ACTUATING MECHANISM l Filed May 1f), 1946 Patented Feb. 10, n1948 VALVE ACTUATING MECHANISM Louis R. Spencer, West Hartford, Conn., assignor to Spencer Aircraft Motors, Inc., Hartford, Conn., a corporation of Connecticut Application May 10, 1946, Serial No. 668,932

Claims. (Cl. 'i4-569) This invention relates to improvements in mechanisms, such as valve actuators, of the type wherein a cam actuated rocker arm engages a valve stem for eiecting reciprocatory motion ci said stem.

f As illustrative of this specific type of mechanism `reference is made to my Patent No. 2,322,173, wherein the rocker arm has a cross pin therein for supporting the cam roller which is adapted to rooperate with a cam shaft for actuating the rocker arm and the primary object of the present invention is to provide an improved bearing or support f or such cam roller in the rocker arm.

More specifically, one object of the present invention is to provide a pivot pin on which the cam roller is journaled, the pin itself being rigidly mounted in the rocker arm.

Another object is to provide the rocker arm with cam roller pin supporting surfaces so constructed that they can be readily lapped or ground in the machining or finishing of said surfaces and in which supporting surfaces the pin can be secured with a pressed, binding fit,

A still further object of the invention is to provide a rocker arm and cam roller assembly in which the cam roller pin has reduced end portions pressed into the supporting surfaces so as to prevent rotation of the pin and said reduced end portions produce shoulders at intermediate points along the pin which engage against the sides of the recess in which the roller is journaled and thereby prevent axial movement or displacement oi the pin.

In the present structure the cam roller is located in a recess in the upper face of the rocker arm with the lower portion of the roller immersed in lubricant in said recess and another object is to minimize the loss of lubricant from said recess by the provision of collecting grooves in the pin which will cause lubricant draining from the roller on to the pin to drop into or be returned to said recess.

With these and other objects in view, the invention consists in certain details of construction and combinations and arrangements of parts, all as will hereinafter be more fully described and the novel features thereof particularly pointed out in the appended claims.

In the accompanying drawing- Figure l is a vertical sectional view through the upper portion of a motor casing illustrating one of the rocker arms. its cam roller and a portion of the valve mechanism in side elevation;

Fig. 2 is a sectional view transversely of the rocker arm on the line 2-2 of Fig. 1;

Fig. 3 is a top plan view of that portion of the rockerarm in which the recess for the cam roller is formed;

Figs. 4 and 5 illustrate, respectively, the cam roller with its pin in end elevation and the recessed portion of the rocker arm in Vertical longitudinal section, these two figures being associated to better illustrate the manner in which the cam roller pin is made to have a pressed binding iit in its supporting surfaces in the rocker arm; and

Fig. 6 is a diagrammatical illustration of the cam roller pin and recessed portion of the rocker arm illustrating the relative diameters of the pin and its arcuate supporting surfaces.

For purposes of illustration, there is shown the upper end oi' one of the valve stems I which control the intake and exhaust valves of the cylinders of an internal combustion engine and, in accordance with usual valve operating mechanisms of this type, each valve is yieldingly held seated by springs II associated therewith and the valves are opened or unseated by their valve stems being depressed by rocker arms I2 under the influence of cams I3 on a cam shaft I4. Preferably, each rocker arm is provided with a replaceable or removable valve stem engaging disk I5 and lubricant is supplied to the surfaces of these disks which contact the rocker arm and valve stem through a conduit I6 in the rocker arm and intersecting conduits I'I, I8, in the disks. These various details of construction are more fully illustrated and described in said Patent No. 2,322,173.

Each` rocker arm I2 is provided with a cam roller I9 which is engaged by one of the cams I3 on cam shaft I4 and the present invention has to do with the construction and mounting of these cam rollers for the purpose of providing a stronger and simplified construction. Each rocker arm is provided with a recess 20 in its upper surface for reception of the cam roller I9, arcuate bearing or supporting surfaces 2| being formed in the rocker` arm at what will be termed the ends of the recess 26. For purposes which will later appear, these arcuate pin supporting surfaces 2I are made to extend slightly more than and correspond in curvature to the reduced ends 22 of a cam roller supporting pin 23 which is adapted to be rigidly secured in the arcuate surfaces 2I of the rocker arm. The camroller I9 is journaled or free to turn on the pin 23 and, as best illustrated in Fig. 2, the intermediate portion of the pin is of a greater diameter than its reduced ends 22, thus forming shoulders which abut against the 3 inner surfaces of what have been termed the end walls of the recess 20. Thus, the pin 23 is held against axial movement in its supporting surfaces.

As previously mentioned, the arcuate surfaces 2| slightly exceed a semi-circle or extend slightly more than 180 and, as will appear from Figs. 4 to 6, the openings or entrances to these arcuate openings, which are relatively restricted, are disposed upwardly with respect to the rocker arm. From the point of restriction the end walls of the. recess in which the supporting surfaces 2| are formed flare or diverge from one, another to facilitate insertion of the pin 23 with its cam roller into the supporting surfaces 2|. As shown in Figs. 4 to 6, the diameter of the reduced ends 22 of the pin slightly exceeds these restricted entrances to the supporting surfaces 2|, so thatY the pin ends have to be pressed into their supporting surfaces, the design of the rocker arm and the nature of the material of which it is made being such as to permit it to be slightly sprung when forcing the pin ends 22 into the arcuate supporting surfaces. Also, as shown in Fig. 6, the diameter of the ends 22 of the roller pin exceeds by one one-thousandth of an inch the diameter of the arcuate supporting surfaces 2| and, as a consequence, not only must the pin be forced through the most restricted portion of the entrance to the supporting surfaces but, after having been pressed into those arcuate surfaces, theV pin will have a rigid binding fit therein. Thus, the construction might be said to be highly simplified in that the pin, though separable fromits roller, is securely and rigidly locked in its supporting surfaces both against axial movement and against accidental displacement upwardly with respect to the rocker arm.

Referring again to Fig. 1, the rocker arm I2 is`also formed with a duct |88, which is an extension, so to speak, of duct |8, so that lubricant Will be fed more or less continuously to the recess 20. The amount of lubricant so supplied will, of course, be suihcient to maintain the lower peripheral portion of the roller I9 immersed. As a consequence, the periphery of the roller will continuously carry lubricant upwardly to lubricate the contacting surfaces of the roller and the cam |3 and, as will be apparent, there will be a tendency of this lubricant to drain from the upper portion of the roller on to the reduced ends 22 of the roller pin. In order to prevent escape of this lubricant from the ends of the pin beyond the sides of the rocker arm, grooves 24 are formed in the reduced ends of the pin at the shouders formed by the enlarged intermediate portion of the pin so that oil draining from the roller 9 will enter these grooves 24 and drain back into the recessed portion 29 of the rocker arm.

Reverting tothe operation of forcing the reduced ends of the pin into their seating surfaces, it will be appreciated that the rocker arm should not be sprung beyond its elastic limit and to aid in this assembly operation heat may be applied to the arm while in an assembly xture or the temperature of the pin ends might be reduced to cause contraction thereof.

It will thus be apparent that the present roller and its xedly mounted pin produces a simple, sturdy construction capable of taking comparatively heavy loads or stresses and, further, it will also be appreciated that lapping or finishing of the surfaces 2| in the rocker arm be- 4 fore the roller pin is inserted is also simplified to a great extent because the recess extends crosswise entirely through the rocker arm in the sense that the bearing surfaces 2| are, essentially, extensions of the cam recess 20.

What is claimed is:

1. A= valve actuating mechanism comprising a. valve stem rocker arm and a cam roller carried thereby characterized by said arm having a recess extending therethrough with the ends of said recess of less depth than the intermediate portion thereof and of arcuate formation longitudinally of the arm, and a pin on which said roller is journaled, saidA pin having its ends rigidly mounted in the arcuate ends of the recess, the intermediate portion of the pin being of increased diameter and abutting against the ends of said recess to prevent axial movement of the pin.

2. A valve actuating mechanism comprising a valve stem rocker arm and a cam roller carried thereby characterized by said arm having a recess extending transversely therethrough with the end portions of less depth than the intermediate portion thereof and of arcuate formation longitudinally of said arm to form pin supporting surfaces, and a pin on which said roller is journaled, said pin having reduced end portions of a diameter slightly exceeding that of the pin supporting surfaces whereby said pin ends can be mounted in the bearings with a pressed fitto bind the pin in the arcuate surfaces and the intermediate portion of the pin having shoulders thereon abutting the opposed end walls of said recess.

3. A valve actuating mechanism comprising a valve stem rocker arm and' a cam roller carried thereby characterized by said arm having a recess extending transversely therethrough with the end portions of less depth than the intermediate portion thereof and of arcuate formation longitudinally of said arm to form pin supporting surfaces, a pin on which said roller is journaled, annular shoulders on said pin abutting the end portions of said recess, the ends of said pin being of a reduced diameter but exceeding the diameter of their supporting surfaces whereby the pin will bind in said supporting surfaces, and grooves in the ends of said pin located at the inner edges of said bearing surfaces.

4. A valve actuating mechanism comprising a valve stem rocker arm and a cam roller carried thereby, a pin on which said roller is journaled, said pin having reduced end portions and said arm having a recess extending transversely therethrough with the end portions of said recess of arcuate formation longitudinally of the arm to form supporting surfaces for the ends of the pin and the intermediate portion of said recess being of greater depth than said arcuate end portions, each of said arcuate bearing surfaces extending slightly more than and having. a restricted entrance opening for insertion of the ends of the pin into their supporting surfaces, the reduced ends of the pin being of a diameter slightly exceeding that of their arcuate supporting surfaces but capable of being forced through said restricted entrance openings whereby the pin will be forced in its supporting surfaces with a binding t.

5. A valve actuating mechanism comprising a valve stem rocker arm having a recess in its uppei` surface with cam roller pin supporting surfaces at the ends of said recess adjacent the side surfaces of the rocker arm, a cam roller pin cam roller'jinto said grooves will be returned by gravity to "said recess.

' LOUIS R. SPENCER.

6 REFERENCES cnnn The following references are of record in the le of this patent:

5 UNITED STATES PATENTS Number Name Date 2,322,173 Spencer June 15. 1943 2,385,309 Spencer Sept. 18, 1945