US1612792A - Valve-operating mechanism - Google Patents

Description

Jan. 4,- 1927. 1,612,192

D. F. ASBURY VALVE OPERATING MECHANISM F iled Feb. 1924 2 Sneets-Sheet 2 Patented Jan. 4, 1927.

rarest DORSE Y F. ASBURY, OE WASHINGTON, DISTRICT OF COLUMBIA.

VALVE-OPERATING MECHANISM.

Apylcaticn filed February 21, 1924. Serial No. 694,368.

My invention relates to valve operating mechanisms of the rocker arm type, and my purpose is to improve the construction and mode of operation of such mechanisms 5 whereby noise, wear and the necessity for lubrication and frequent adjustments of parts is eliminated, all as set forth in my prior applications 374,996 and $7 1,998, of which this application, in part, is a continuation. Said applications have matured into patents numbered 1,557,548, of Oct. 20, 1925, and 1393320, of may 6, 1924, respectively.

My inventive idea is capable t embodiment in different mechanical structures, certain of which are shown in the accompanying drawings, but it is to be understood that the structures shown are merely intended as disclosures of the essential features and novel characteristics of my invention in certain preferred forms and that its scope is as defined in the appended claims.

In the drawings, wherein like characters of reference denote corresponding parts in the different views- Figure 1 is a vertical section of a valve operating mechanism embodying the novel features of my invention, the parts being shown in the positions they occupy when the valve is closed;

Figure 2, a view similar to Figure 1 showing the positions of the parts when the valve is open; 2

Figure 3, a transverse section on the line 33 of Figure 1;

Figure 1-, a perspective of the rocker arm fulcrum member;

Fig. 5 is a perspective view of the rocker arm.

Figure 6, a view similar to Figure 1 of a modified form of my improved mechanism; and

Figure 7, a transverse section on the line 7-7 of Figure 6.

Referring to the drawings in detail particularly to Figures 1 to 5 inclusive, 1O designates, generally, an internal. combustion engine of the overhead poppet valve type, the same including a cylinder head 11 on the under side of which seats a poppet valve 12, the stem 13 of which extends vertically upward through a guide member 14: in said head and has associated therewith a spring 15 acting to hold the valve normally closed. A pushrod 16 constitutes an actuator for 5 said valve and a. rocker arm 17 bridges the upper ends of said push rod and valve stem whereby movement of the former is trans mitted to the latter.

At the ends of the rocker arm are recesses 18 and 19 that loosely receive the upper end portions of the push rod and valve stem, respectively, and within said recesses are convex surfaces 20 and 21 respectively, that contact with the flat upper ends of said push rod and valve stem. I

In the upper face of the rocker arm, intermediate its ends, is a trough 22 which trough is of V-shaped cross section and extends longitudinally of the rocker arm, its end limits being defined by suitable stops or pins 23, 24.

On the engine is aflixed a bracket 25 and on a horizontal arm 26 of said bracket is mounted a support for the rocker arm in the form of a flexed leaf spring yoke 27 through which the rocker arm extends and which carries a ball 28 at its upper end seated within the V-shaped trough 22 of the rocker arm, while at its lower end it carries a cylindrical bearing member 29 contacting with the under flat face of said arm 26.

Yoke 27 consists of spaced side portions 30, 31 and upper and lower portions 32, 33, respectively, connecting said side portions, and as a convenient and efficient means of mounting the ball 28 and bearing member 29 on said yoke both the ball and said bearing member are slotted and inter-fitted with. the end connecting portions 32, 38, between and in contact with the side portions 30, 31,

whereby they are held against movement in I all directions with respect to said yoke when the mechanism is assembled.

With the push rod 16 in its lowermost position and valve 12 closed, as shown in Fig ure 1, the parts of the mechanism are maintained in contact by the inherent resiliency and fiexure of. yoke 27 which latter is bowed in the direction of-the valve stem, but the valve is held against its seat because of the fact that spring 15 is much stronger than the spring constituted by said yoke. When push rod 16 begins to move upward, however, rocker arms 17 fulcrums on the upper end of the valve stem, which latter is held against lateral movement due to its snug fit within guide member 14, until yoke 27 substantial- 1y s ,raightens under the operating force thus imparted to the mechanism, ball 28 at the same time rolling on the rocker arm and its points of contact therewith shitting towards the valve stem due to the yoke being bowed in that direction and when yoke 2? straightens and thus becomes a positive acting ele ment of the mechanism, the fulcrum of the rocker arm is shifted thereto from the valv stem and continued upward movement of the push rod accordingly results in rocking of the rocker arm on the ball 28 with consequent depression of the valve stem and open ing of the valve. As the rocker arm rocks on the ball. 28, the latter rolls on the rocker arm and its points of contact therewith shift towards the push rod.

Since the valve stem 13 cannot move laterally in any direction due to same being guided in meu'iber 14, it is necessary in order to secure rolling contact between its flat up per end and the convex surface 21 of the rocker arm, that the rocker arm be capable of longitudinal movement during operation of the mechanism, and as is apparent, such movement of the rocker arm is permitted because 01 the fact that it is supported on a swinging fulcrum member. The push rod 16 is flexible and therefore rolls on convex surface 20 oil the rocker arm during operation of the mechanism because its flexibility permits it to accommodate itself to movements partaken by the rocker arm. Ball 28 riding in trough 22 provides shiftable rolling contact between the rocker arm and the fulcrum member to accommodate tlex ures of bowed yoke 27, and cylindrical member 29 provides rolling contact between said fulcrum member and a lined part of the en'- gine constituted by bracket 25, not only to accommodate flenures of the bowed yoke 27, but to accommodate swinging movements or". said yoke.

By providing a cylindrical bearing member 29 having line contact with the flat under 'liace or arm 26, the l lllCl'lUil member is held agaii'ist lateral tilting n'iovcinent transverse ly of the plane of movement oi the rocker arm. and consequently the rocker arm is he] d against such lateral movement due to the two point contact between ball 28 and the con verging surfaces of i -shaped trough 22, while in addition, such two point contact of said ball with said converging or inclined surfaces serves to center the rocker arm with resortto the yoke 2? and thus maintains a lug clear: we or non-rubbing relation n the s des or" the rocker arm and the V od rs oi the side portions 30, 31. ln the inrulilicaiion oi the foregoing ar- 'rment shown in Figures 6 and i, the tub cruni member 27 which is Formed from inherently rigid niateial. is provided at its upper end with a lateral, offset portion 34 overlying the rocker arm and at its lower and with a lateral oft-set portion 35 underlying arm 26 of bracket in the up per face of the rocker arm 1s formed a V- llii'lll shaped trough 22' and in the under 'lace ol otlset portion is formed a corresponding ii-shaped trough 36, while disposed between the rocker arm and said oil'set portion and having rolling contact with the inclined side walls of both of said troughs is a ball 28. The troughs 22 and 36 extend longltin dinally with respect to the rocker arm and are arcuately curved on radii somewhat longer than the radius of ball 28, so that they form wedge surfaces cooperating with said ball upon longitudinal movement of the rocker arm with respect to the fulcrum meniher to maintain the parts of the mechanism in contact. A light bowed spring 37 connected at one end to the rocker arm and engaged at its other end with the fulcrum member imparts the necessary force to cause the aforesaid wedging action to maintain the parts of the mechanism in contact.

-The under -face of arm 26 of bracket 25 is conveXly curved and the upper face of oilset portion of the fulcrum member that contacts therewith is flat whereby rolling contact is provided between the fulcrum member and the bracket and whereby the fulcrum member is held against lateral swinging movement transversely of the plane of movement of the rocker arm, and because of the two-point contact of ball 28 with the inclined surfaces or each trough 22 and 36, the rocker arm is held against like lateral movement as well as out of rubbing contact with the fulcrum member.

A pin 38 projects from each fulcrum member and when the latter are arranged in pairs as shown in Figure 7, the ends of the pins engage with each other to hold the fulcrum members against lateral movement transversely of the plane of movement of the rocker arm.

In operation, when push rod 16 moves upward the force of spring 37 is overcome and ball 28 first rolls to the lowest point in each trough 22 and 36, the fulcrum member swinging slightly under the influence 0f the operating force thus imparted to the mechanism to permit such roll, after which the rocker arm rocks on the ball as described in connection with Figures 1 to 5 and the valve is opened.

I claim l. in a valve operating mechanism, a valve including a stem, an actuator, a rocker arm between said valve and actuator, an inherently resilient fulcrum support for said rocker arm movable longitudinally of said rocker arm to permit said rocker arm to roll on said valve stem and acting to maintail the parts oi the mechanism in contact, and a connection between said fulcrum support and rocker arm permitting the latter to rock with respect to the former.

2. In a valve operating mechanism, a valve including a stem, an actuator, a rocker lit) arm between said valve and actuator, an in. herently resilient fulcrum support for said rocker arm movable longitudinally of said rockerarm to permit said rocker armto roll on said-valve stem and acting to maintain the parts of the mechanism in contact, and rolling means between said fulcrum suppcrtand said rocker arm.

3. In a valve operating mechanism'fo'r engines, a valve including a stem,an actuator, a rocker arm between said valve and -actuator, an inherently resilient fulcrum support for said rocker arm movable to permit said rocker arm to roll on said valve stem and acting to maintain the parts of the mechanism in contact, said fulcrum support being supported from a fixed part of the engine, and rolling means between said fulcrum support and said fixed part.

4-. In a valve operating mechanism, a valve, an actuator, a rocker arm and a fulcrum member therefor the former of which is longitudinally movable with respect to the latter, and rolling means between said fulcrum member and said rocker arm holding the latter against lateral movement with respect to the former.

5. In a valve operating mechanism, a valve, an actuator, a rocker arm and a fulcrum member therefor the former of which is longitudinally movable with respect to the latter and one of which is provided with in clined surfaces, and means between said rocker arm and said fulcrum member rolling on said inclined surfaces and cooperating therewith to hold said rocker arm against lateral movement with respect to said fulcrum member.

6. In a valve operating mechanism for engines, a valve, an actuator, a rocker arm between said valve and actuator, a fulcrum member for said rocker arm supported from a fixed part of the engine, rolling means between said fulcrum member and said fixed part, means holding said fulcrum member against lateral movement with respect to the plane of movement of said rocker arm, and rolling means between said fulcrum member and said rocker arm permitting the rocker arm to move longitudinally and holding the same against movement laterally with respect to the fulcrum member.

'7. In a valve operating mechanism, a rocker arm and a support therefor one of which is provided with a trough of t -shaped cross section extending in adirection longitudinally with respect to the rocker arm, and means rolling in said trough holding the rocker arm against lateral movement with respect to its support.

8. In a valve operating mechanism, a rocker arm and a support therefor one of which is provided with a trough extending in a direction longitudinally with respect to the rocker arm, and. a single member rolling in said trough and acting to holdthe rocker" arm. againstlateral movement with respect to said support.

9. In a val-veunechanism' for'engines,-a'

members havingkslots rece'ivi-ngthe' ends of rocker arm; a support therefor, and-bearing having a slot receiving an end portion' of said support and having rolling contact with said rocker arm.

11. In a valve mechanism for engines, a rocker arm, a support therefor, and a bearing member having a slot receiving an end portion of said support and having rolling contact with a fixed part of the engine.

12. In a valve operating mechanism, a valve including a stem, an actuator, a rocker arm between said valve and actuator, a normally flexed inherently resilient swinging fulcrum member for said rocker arm con nected at one end to the engine, and rolling means at the other end of said fulcrum member between said fulcrum member and said rocker arm.

13. In a valve operating mechanism. a valve including a stem, an actuator, a rocker arm between said valve and actuator, a resilient fulcrum member for said rocker arm in the form of a leaf spring normally flexed and acting through its resiliency to maintain the parts of the mechanism in contact, said fulcrum member being connected at one end to the engine, and rolling means at the other end of said fulcrum member between said fulcrum member and said rocker arm.

14. In a valve operating mechanism, a valve including a stem, anv actuator, a rocker arm between said valve and actuator, a support for said rocker arm in the form of a yoke comprising spaced side portions and end portions connecting them, and bearing members at the ends of said yoke having rolling contact, respectively, with said rocker arm and with a fixed part of the engine, said support being inherently resilient and normally flexed whereby it acts to maintain the parts of the mechanism in contact.

15. In a valve mechanism for engines, a rocker arm, a support therefor in the form of a yoke comprising spaced side portions and end portions connecting them, and slotted bearing members interfitted by means of their slots with said yoke at the ends thereof and having rolling contact, respectively, with the rocker arm and a fixed part of the engine, said bearing members being disposed between and in contact with said side portions whereby they are held against movement with respect to said support.

16. In a valve operating mechanism, a

valve including a stem, an actuator, a rocker arm between said valve and actuator, a swinging fulcrum member for said rocker arm, and rolling means between said fulvcrum member and said rocker arm, said fulcrum member being inherently resilient and bowed in the direction of said valve stem.

17. In a valve operating mechanism, a valve including a stem, an actuator, a rocker arm between said valve and actuator, a resilient normally flexed fulcrum member for said rocker arm acting through its resiliency to maintain the parts of the mechanism in contact and adapted to be straightened under th influence of an operating force imparted to the mechanism, rolling means between said fulcrum member and said rocker arm, and means whereby said rolling means shifts longitudinally of the rocker arm in the direction of said valve stem when said flexed fulcrum member is straightened.

In testimony whereof I hereunto affix my signature;

DORSEY F. ASBURY.

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