US3882834A - Valve lash adjuster - Google Patents

Abstract

An adjuster is provided for setting lash between an engine valve and an associated rocker arm, disposed under an engine valve cover. A portion of the adjuster extends through a passage defined by the cover and outwardly thereof, and overrunning clutch and detent means are associated with the adjuster so that lash may be adjusted with the engine running and with the valve cover in place.

Description

Goloff et a1.

1 51 May 13, 1975 [54] VALVE LASH ADJUSTER Ebj iwaad 123/9045 ..,8 an ar 1. 123/9043 [75] lnvemmsi Alexander 90101111535 Pema; Mark 2,884.914 5/1959 Mottershaw 123/9045 Sommars Peona, both of 3,0s7,475 4/1963 Thompson 123/9043 [73] Assignee: Caterpillar Tractor Company,

Peoria, 111. Primary Examiner-Manuel A. Antonakas Assistant Examiner-Daniel J. OConnor [22] Flled' 1974 Attorney, Agent, or Firm-Phillips, Moore, [21] Appl. No.: 437,384 Weissenberger, Lempio & Strabala [52] U.S. C1. l23/90.43; 74/522; 123/9039; [57] ABSTRACT 123/9045; 123/188 An adjuster is provided for setting lash between an en [51] Int.Cl. ..F01ll/20 v] da as ited k I di sd [58] Field of Search 123/9045, 90.43, 188, gm ave n s 9 e 123/90 74/522 under an engme valve cover. A portion of the ad uster extends through a passagedefined by the cover and [56] References Cned outwardly thereof, and overrunning clutch and detent means are associated with the adjuster so that lash UNITED STATES PATENTS may be adjusted with the engine running and with the l 188,405 6/1916 Brush 123/9043 valve cover in place 2,343 O67 2/1944 Luce 123/9045 2,397.502 4/1946 Ralston 123/188 8 Claims, 3 Drawing Figures 11 5 6L 1 a '1 1 I 56 60 1 20 y I 1 3H 1 2 I 1 1 I 29 11 1 1 1 1 1 l 1 11 g VALVE LASI-I ADJUSTER BACKGROUND OF THE INVENTION This invention relates to an adjustment of parts associated with the valves of engines, and more particularly, to a device for adjusting lash between a valve and an associated rocker arm.

Because of expansion of internal combustion engine parts from heat generated during engine operation, it is common to provide an amount of lash or play between the end of the valve stem and rocker arm which it contacts. Without such lash, the expanded parts might be severely stressed and subjected to possible ultimate failure.

In the conventional arrangement of parts associated with the valve, in which a rocker arm extends between the stem end of the valve and the end of a push arm and pivots about a ball pivot, lash adjustment has been accomplished with the engine stopped and the valve cover removed, through adjustment of a member on the end of the rocker arm contacting the push rod. The common procedure involves use of a feeler gauge between the end of the rocker arm and stem end of the valve, and adjustment of the member at the opposite end of the rocker arm to obtain desired clearance between the rocker arm and valve. Such procedure obviously is time consuming and results in high labor costs. It has been found, for example, that in a six cylinder engine having four valves per cylinder, total adjustment time may average on the order of 1 hour and I2 minutes.

SUMMARY OF THE INVENTION It is an object of this invention to provide a valve lash adjusting system which may be utilized with the engine running, and without removal of the valve covers thereof.

It is a further object of this invention to provide a valve lash adjusting system which operates through mechanical means.

It is a still further object of this invention to provide a valve lash adjusting system which, while fulfilling the above objects, provides that the degree of lash can be precisely set and maintained during operation of the engine.

It is a still further object of the invention to provide a valve lash adjusting system which, while fulfilling the above objects, is simple in design and effective in use.

Broadly stated, the invention is in a system having a rocker arm pivotable about a pivot member to actuate a valve, and adjusting means associated with the rocker arm and pivot member and movable in first and second directions to respectively decrease and increase lash between the valve and rocker arm. Such invention comprises an adjustment member, and means interconnecting the adjustment member and adjusting means for providing that (i) the adjustment member is movable in one direction to move the adjusting means in the first direction to decrease the lash to a level of substantially zero, with further movement of the adjustment member in the one direction providing no further movement of the adjusting means in the first direction. The adjustment member is movable in another direction to move the adjusting means in the second direction to increase the lash. The invention also comprises detent means for indicating the extent of movement of the adjustment member, and restraining means for restraining the adjusting means and adjustment member from inadvertant turning.

BRIEF DESCRIPTION OF THE DRAWINGS These and other objects of the invention will become apparent from the following description and drawings, in which:

FIG. 1 is a fragmentary, vertical sectional view of a valve-rocker arm assembly incorporating the lash adjuster of the present invention;

FIG. 2 is a vertical sectional view of a preferred form of lash adjuster of this invention and associated valve and rocker arm; and

FIG. 3 is a cross-sectional view of the valve lash adjuster of FIG. 2 taken along the line III-III of FIG. 2.

DESCRIPTION OF THE PREFERRED EMBODIMENT In detail, with reference to FIG. 1, a preferred embodiment of the valve lash adjuster, generally designated at 10, is shown with associated conventional engine parts including a valve 12 received within a cylinder head 14, and having a valve head 16 urged in a seating position by a spring 18 extending between head 16 and a valve keeper 20. A camshaft 22 imparts axial motion through a lifter 2 4 to a push rod 26. A rocker arm 28 is mounted on a stud 29 secured to the head 14 and extends between the stem end of valve 12 and an end of the push rod 26, which includes a ball member 30 in contact with the end of the push rod 26. The stud 29 is slidably received through a ball pivot 32 and threaded through an adjusting nut 34 which can be tightened against the ball pivot 32 for constraining the ball pivot 32 in a seating relationship against rocker arm 28, and rocker arm 28 in turn against the stem end of valve 12 and the end of the push rod 26, through the ball 30. The rocker arm 28, it will be seen, is pivotable about the ball pivot 32 during actuation of the valve 12.

In the preferred form, adjusting means 36, including an adjusting socket 38 and the nut 34, the head of which is receivedtherein, are included. Rotation of the socket 38 in a first direction moves the nut 34 to tighten the ball pivot 32 against the rocker arm 28, decreasing lash between the rocker arm 28 and valve 12, and rotation of the adjusting socket 38 in a second, opposite direction, turns the adjusting nut 34 therewith to increase such lash. A peripheral annular flange portion 40 of the socket 38 carries an adjusting cap 42 overlying the portion of socket 38 having bore 44. The cap 42 includes an annular flange 46 which is disposed on flange portion 40 of the socket 38, and which has formed at its internal surface a plurality of similar arcuate ramp or wedge-shaped ways 48.

As seen in FIG. 3, each way 48 and the associated outer surface portion of the socket 38 provides an annularly tapered opening for receipt of a ball 50 and coil spring 52 disposed between the ball 50 and the broader end of the way 48. The diameter of the ball 50 is slightly larger than the width dimension of the narrow end 54 of the way 48, so that a wedging action occurs upon urging the ball 50 toward narrow end 54 which end is the leading end during clockwise rotation of the cap 42.

The periphery of flange portion 46 of cap 42 has a plurality of equally spaced V-shaped notches 56, and the periphery of flange 40 on socket 38 has a serrated surface 58. An arcuate spring extends around one half the perimeter of the flanges 46,40 and terminates in opposed V-shaped ends 62, each for grippingly seating within a notch 56 and an aligned serration of serrated surface 58. The spring 60 includes a Ushaped midportion 64 secured to a dowel 66 which is fixed to cylinder head 14. The arrangement of spring 60, notches 56 and serrated surface 58 provides a detent system for indicating and maintaining the rotational positions of socket 38 and cap 42. A snap ring 68 is provided for securing socket 38 and cap 42 together, and a pin 70 is fixed centrally of cap 42 and extends axially to within a seat 72 in the upper end of stud 29 for maintaining secure axial alignment of cap 38 and socket 42.

In such system, the rocker arm 28 and valve 12, and adjusting means associated therewith, have a valve cover 74 generally disposed thereover. The cap 42, which acts as an adjustment member as later explained, extends through a passage 76 defined by the cover 74, and is exposed outwardly thereof, as shown in FIGS. 1 and 2.

In operation, the valve lash adjusting means of this system may be used to adjust valve lash with the engine running, and without removal of the valve cover 74. In such state, the adjusting cap 42 is turned in such first direction, moving ball pivot 32 downward to decrease lash or play between the valve 12 and rocker arm 28. The springs 52 are of sufficient stiffness that during such clockwise turning of the cap 42 (see FIG. 3), the balls 50 are urged by the springs 52 into a wedged condition between the surfaces of way 48 and socket 38 with sufficient frictional contact with socket 38 to cause it to turn with cap 42 until socket 38 has turned nut 34 to tighten ball pivot 32 against rocker arm 28 sufficiently to eliminate rocker arm play. This tightening is accomplished during the periods the lifter is on the base circle of the cam and little torque is needed to move socket 38. Upon reaching such state, and upon further attempt to tighten the nut 34, the balls 50 are released from the wedged position against the force of the springs 52, causing slippage and preventing further tightening. Thus, constant initial no-lash setting can be achieved. During clockwise turning of the cap 42 and socket 38, the ends 62 of spring 60 are lifted from successive notches when therebetween, and therefore, the ends 62 of such spring 60 do not act on the serrated surface 58. Such disengagement from the serrations allows the clutching system described above to operate properly. Such ball and way system, in accordance with the above description, acts as over-running clutch means for providing that, once zero lash is achieved, further movement of the cap in such direction provides no further movement of the socket 38 and nut 34.

Through the use of such overrunning clutch, upon achievement of substantially zero lash as described above, the cap 42 may be turned further in such clockwise direction until the spring ends 62 are seated in notches 56, to provide base setting of the cap 42 corresponding to zero lash. The cap 42 may then be backed up through one or more detents, so that, depending on the number of clicks counted, accurate setting of lash can be achieved.

When adjusting cap 42 is turned in the counterclockwise direction, the balls 50 are wedged against the surface of the socket 38 for turning the socket 38 and loosening the nut 34. During turning of cap 42 in such counter-clockwise direction, the ends 62 of the spring 60 are displaced from and seated within successive notches 56, causing a series of audible and feelable clicks giving direct indication of the extent of rotation of the cap 42. Because there is a known relationship between the extent of rotation and axial movement of the nut 34, one can immediately accurately set the valve lash by counting such number of clicks. Circumferential spacing between the notches 56 can be selected so that the rotation required to displace an end 62 of spring 60 from one notch 56 to the next click will, for example, yield 0.010 inch axial travel of nut 34. In addition to providing an audible click or signal of the amount of valve lash, the spring 60 also serves to restrain the cap 42 and socket member 38 from inadvertent turning, which might be induced by vibration during engine operation.

It is to be understood that cap 42 need not extend through the cover 74, but may be positioned immediately below such cover 74, and a suitable easily removable stopper may be provided above it, so that the stopper may be easily removed, and the lash set.

Accordingly, the above-described invention provides a mechanism for adjusting lash between a valve and associated rocker arm pivotable about a ball pivot and mounting stud. The overall system it will be seen, is extremely simple, and is very efficient in use. The system is designed for use with the engine running, and the valve cover thereof need not be removed.

What is claimed is:

1. In a system having a rocker arm pivotable about a pivot member to actuate a valve, and adjusting means associated with said rocker arm and pivot member and movable in first and second directions to respectively decrease and increase lash between the valve and rocker arm, an adjustment member, and means interconnecting the adjustment member and adjusting means for providing that (i) the adjustment member is movable in one direction to move the adjusting means in said first direction to decrease said lash to a level of substantially zero, with further movement of said adjustment member in said one direction providing no further movement of said adjusting means in said first direction, and (ii) movable in another direction to move the adjusting means in said second direction to increase said lash.

2. The system of claim 1 wherein the means interconnecting the adjustment member and adjusting means comprise overrunning clutch means.

3. The system of claim 1 and further comprising detent means for indicating the extent of movement of said adjustment member.

4. The system of claim 1 further comprising means for restraining the adjusting means and adjustment member from inadvertant turning.

5. In a system having a rocker arm pivotable about a pivot member to actuate a valve, and adjusting means associated with said rocker arm and movable in first and second directions to respectively decrease and increase lash between the valve and rocker arm, and a cover generally disposed over the rocker arm and valve and adjusting means, an adjustment member movable in one direction to move the adjusting means in said first direction to decrease said lash, and movable in another direction to move the adjusting means in said second direction to increase said lash, the cover defining passage means allowing access to the adjustment member providing movement of said adjustment member in said one and said other directions, and means interconcover.

7. The system of claim 5 and further comprising detent means for indicating the extent of movement of said adjustment member.

8. The system of claim 7 and further comprisin means for restraining the adjusting means and adjustment member from inadvertant turning.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION PATENT NO. 2 3 882 831; DATED May 13, 1975 INVENTOR(S) Alexander Goloff, et a1 It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

On the Title Page, Item [73], change the spelling of the assignee's corporate name from "Caterpillar Tractor Company" to -Caterpillar Tractor Co.--.

Signed and Sealed this twenty-eight D8) Of October 1975 [SEAL] Attest:

RUTH C. MASON C. MARSHALL DANN Arresting Officer Commissioner ufPatenrs and Trademarks

Claims (8)

1. In a system having a rocker arm pivotable about a pivot member to actuate a valve, and adjusting means associated with said rocker arm and pivot member and movable in first and second directions to respectively decrease and increase lash between the valve and rocker arm, an adjustment member, and means interconnecting the adjustment member and adjusting means for providing that (i) the adjustment member is movable in one direction to move the adjusting means in said first direction to decrease said lash to a level of substantially zero, with further movement of said adjustment member in said one direction providing no further movement of said adjusting means in said first direction, and (ii) movable in another direction to move the adjusting means in said second direction to increase said lash.

2. The system of claim 1 wherein the means interconnecting the adjustment member and adjusting means comprise overrunning clutch means.

3. The system of claim 1 and further comprising detent means for indicating the extent of movement of said adjustment member.

4. The system of claim 1 further comprising means for restraining the adjusting means and adjustment member from inadvertant turning.

5. In a system having a rocker arm pivotable about a pivot member to actuate a valve, and adjusting means associated with said rocker arm and movable in first and second directions to respectively decrease and increase lash between the valve and rocker arm, and a cover generally disposed over the rocker arm and valve and adjusting means, an adjustment member movable in one direction to move the adjusting means in said first direction to decrease said lash, and movable in another direction to move the adjusting means in said second direction to increase said lash, the cover defining passage means allowing access to the adjustment member providing movement of said adjustment member in said one and said other directions, and means interconnecting the adjustment member and adjusting means for providing that the adjustment is movable in said one direction to move the adjustment means in said first direction to decrease said lash to a level of substantially zero, with further movement of said adjustment member in said one direction providing no further movement of said adjusting means in said first direction.

6. The system of claim 5 wherein the adjustment member extends through the passage outwardly of the cover.

7. The system of claim 5 and further comprising detent means for indicating the extent of movement of said adjustment member.

8. The system of claim 7 and further comprising means for restraining the adjusting means and adjustment member from inadvertant turning.

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