US2873730A

US2873730A - Fulcrum adjuster

Info

Publication number: US2873730A
Application number: US669512A
Authority: US
Inventors: Charles R Kilgore
Original assignee: Thompson Products Inc
Current assignee: Northrop Grumman Space and Mission Systems Corp
Priority date: 1957-07-02
Filing date: 1957-07-02
Publication date: 1959-02-17
Anticipated expiration: 1976-02-17

Description

Feb. 17, 1959 c. R. KILGORE 2,873,730

FULCRUM ADJUSTER Filed July 2, 1957 2 Sheets-Sheet 2 L21? IzZb 2 Charles .72. [Ci/ yore States Patent 2,873,730 FULCRUM ADJUSTER Charles R. Kilgore, Cleveland, Ohio, assignor to Thompson Products, Inc., Cleveland, Ohio, a corporation'of Ohio a I 1 Application July 2, 1957, Serial No. 669,512 17 Claims. (Cl. 123-90) The present invention relates to improvements in lash adjusters for engine valve linkages. More particularly, the invention relates to an improved oil operated mechanism whichprevents excessive and objectionable lash in the operation of engine valves wherein the lash adjuster or preventer is mounted on an engine to pivotally support 2 ber remains stationary and a central plunger oscillates during engine operation.

A further object of the. invention is to provide a las preventer and fulcrum adjuster wherein only .one dynamic seal is required thereby reducing drag and speeding recovery during starting and improving low temperature operation. v

An object of the invention is to provide an improved piston and cylinder type fulcrum adjuster with improved oil delivery to the pressure chamber under both starting conditions and runningconditions, and wherein a controlled escape flow of oil is permitted from the pressure chamber during a valve opening stage of operation with a positive replenishment of oil during a valve closing stage of operation. J I

' A further object of the invention is to provide an improved lash preventing fulcrum adjuster for an overhead valve linkage wherein a fluid supply may be received'from a sealed reservoir with built in pressurizing means.

end with the reciprocating stem of a valve. The rocker arm may have an opening through the depressed. portion for the passageof a mounting stud or post projecting upwardly from the'engine and serving to support the lash adjusting unit. The stud or post may be provided with an oil passageway theretbrough communicating with the pressurized oil supply of the engine to deliver pressurized oil to the lash adjusting unit, or in one form, the unit is self-sufficient- An'object of the invention is to provide an improved lash preventing mechanism for pivotally supporting the rocker arm in an engine valve linkage wherein the mechanism is utilized as an integral unit for improved operation and simplicity of handling and assembly.

Another object of .the invention is to provide a lash preventing mechanism which serves as a fulcrum adjuster for the rocker arm of an engine valve linkage.

Another object of the invention is to provide a fulcrum adjuster for an engine valve linkage wherein the operating clearances are simply and" readily adjusted according to the requirements of the engine without'the necessity of providing close manufacturing tolerances.

Another object of the, invention is to provide an improved lash preventing device and fulcrum adjuster which is provided with an internal engine oil reservoir for improved operation during starting.

A further object of the invention is to provide an improved fulcrum adjuster wherein entrapped air is removed from the oil and is prevented from reaching the high'pressure chamber.

Another object of the invention is to provide a fulcmm adjuster in'which an oil leak-down passage is provided and wherein the passage can be constructed to-be annular proved fulcrum adjuster wherein the outer barrel mem- Other objects and advantages will become more apparent with the disclosure and teaching ofothe principles of the invention in connection with the description of the preferred embodiment in the drawings, specification and claims, inwhich:

Figure 1 is a vertical. sectional view taken through a valve assembly employing a fulcrum adjuster of the pres ent invention; v

Figure 2 is a plan view of the top of the rocker arm, somewhat enlarged from Figure. 1,, and with the valve and engine block removed;

Figure 3 is an enlarged verticalsection taken through the fulcrum'adjuster assembly;

' Figure 4 is an enlarged side elevational view of the fulcrum adjuster in position supporting the rockerarm with a portion of the fulcrum adjuster housing broken y; A

Figure 5 is an enlarged fragmentalsectional view of the fulcrum adjuster illustrating the operationof the oil valve during the' time the oil is being'r'eplenished to the pressure chamber; I

Figure 6 is an enlarged fragmental sectional view similar to Figure 5, and illustrating theposition of the valve during starting of the engine; and,

Figure 7 is a vertical sectional view taken through a fulcrum adjuster mechanism of another form.

Although the fulcrum adjuster mechanism is shown in its preferred forms as utilized for preventing valve lash of an engine-valve linkage, it will be understood that the principles of the invention may be utilized in other environments, taking advantage of their inherent features and uses.

In the'valve linkage-assembly shown in Figures 1 and 2, the internal combustion engine is shown generally at 10, and includes a cylinder, block 11 with a cylinder head 12. The head 12 has a guide 13 receiving in slidable relation therein the stem 14 of the poppet valve 15.

- The head 16 of the valve cooperates with the seat' 17 in the engine head 12 to control the flow of gases be tween the valve port '18 and thecombustion chamber 19.

The upper end of the valve stem 14 has grooves 20 thereon, and the conventional split valve locks 21 have beads which seat in these grooves. A valve spring retainer 22 is fixedly held on the upper end of the valve stem by the locks 21 which are tapered, and a valve spring 23 surrounds the valve stem and has one end bottomed on the retainer 22 and :the other end bottomed on the shoulder 24: of the engine head 12 surrounding the guide 13. .The valve stem 23 is thus biased to hold the valve 16 against its seat 17.

The rocker arm is shown in the form of a stamped sheet metal arm 25 having a depressed fragmental spherical socket portion 26 in the bottom thereof with an aperture 27 through the bottom of the socket. The rocker arm is surrounded by an upturned peripheral flange 28 to have a generally bowl-shaped interior 29. At one end ofthe rocker arm and at one side of the socket 26, the bottom of the bowl 29 is raised to provide an inverted socket 30 for the rounded end 31' of a push rod 32. The push rod 31 can rock in the socket 2t] and oil aperture 33 is provided through the socket to lubricate the end 31 of the push rod. On the opposite side of the socket 26 and on the opposite end of the rocker arm, the bowl: shaped bottom portion 29 of the rocker arm is depressed at 34' to provide a round exterior for engaging and rocking on'the end 35 of the valve stem 14.

Q In accordance with this invention, the rocker arm is: pivotally supported. in its operating position on the engine valve head 12 by means of an automatic lash adjuster or preventer or an automatic fulcrum adjuster, such as is shown generally at 36.

The fulcrum adjuster 36 is supported in its operating position to pivotally carry the rocker arm. 25, on a post 38 which is suitably attached to the engine head 12 and may be threaded into an opening 40 at the top of the 7 engine head 12. In this location, thepost 38 communicates with an oil ehamber42, which is supplied with pressurized oil from the oil pump of the engine. The pressurized oil is fed up through the centerv of the post which has a coaxially centrally extending oil passageway 44 to pressurize the oil pressure chamber 46 in a manner which will be described.

As illustrated in Figure 3, the supporting post 38 has a smooth cylindrical exterior to slidably receive the bearing member 47. The-bearing member 47 likewise has a smooth cylindrical interior bore 48 extending therethrough .in order to slidably move on the post. The bore 48 is slightly largerthan the exteriorssurface 44 of the post, so as to form an oil leak-down passageway 50. The bearing member 47, which is slidably positioned on the post 38, is also slidably received by the reaction member 54. The reaction member 54 may be of a stamped or pressed steel cup or the like and has a cylindrical interior 56. At its upper end 57, the reaction member or cup 54 is turned inwardly over the top of the bearing member 47 to meet the post 38 and has .a circular hole 58, through which the upper end of the post 38 passes. The turned-in top portion 57 of the reaction member-.54 forms a shoulder against which presses a nut 60 and a washer 66 to determine the position of the reaction member 54011 the post. The nut may be used without a wa'sherif desired and is carried on the threaded upper -end 68 of the post and may be adjustably turned up or down to fix the operating position of the reaction member. Thus, this adjustment can be made easily and it is not necessary that the post 38 be provided with accurate-manufacturing tolerances, and the position of the fulcrum adjuster unit 36 can be readily set in accordance with the conditions presented by the rocker arm 25 and its associated valve 15 and push rod 32.

It will be seen from the drawings, that the bearing member 47 and the reactionmember 54 which is telescoped over the top thereof, form a compactunit cartridge which issimple to'handle and assemble. To maintain the bearing 47 and reaction member 54 together, the lower edge of thecup=shaped reaction member is staked, such as at

locations

70 and 72, shown in Figures 1, 3 and 4.

.The reaction member 54 andthe bearing member 47 form the oil pressure chamber-46 between them wherein the pressurized oil urges the bearing member 47 to extended position with respect to the reaction member 54'as it is fixed in position by thenut 60 at the top of the post 38. The lower end of the oil pressure chamber-464s closed by a dynamic seal 74, shown in the shapeof 'anannular sealing ring which may be ls-shaped in cross section. The base 76 of the ring seats against a shoulder 78 formed on the bearing member 47. The outer leg 80 of a dynamic seal 74 rides against the inner cylindrical wall 56 of the reaction member 54. The dynamic seal is held against the shoulder 78 by the valve support spring 82 which is a spiral coiled compression spring located in the pressure chamber 46.

The upper end of the pressure chamber 46 is defined by the annular sleeve 84, which is press fit within the cup-shaped reaction member 54. I M

The sleeve 34 has an upwardly extending flange. 86 at its upper end which meets the inwardly turned flange 57 at the top of the cup to define an oil reservoir 88.

This oil reservoir communicates with the oil pressure chamber 46 through a plurality of axially drilled oil passageways leading downwardly from the reservoir 88 to the pressure chamber 46 past the annular fluid transfer valve ring 92. The sleeve 84 has an annular oil distribution groove 94 in its lower. face which permits communication between the fluidpassageways 90 and overiwhich is positioned the movable valve ring 92' The valve ring is held in place by a wave spring 96 which bears against its lower surface holdingj'it upwardly in position over the groove 94. The valve supporting wave spring 96' is supported on a valve supporting ring 98, which has an annular upper vertical flange holding the wave spring 96 and the valve ring 92' radially in place, and which has a lower horizontal flange against which bears the valve supportingspring 82 to support the valve spring vertically.

' The operation of this assembly is illustrated in Figures 5 and '6. During normal running operation, when the valve 15. is closing, the oil pressure in the reservoir 88 will be greater than the pressure in the pressure cham ber 46. The valve ring 92 will then open to the position shown in Figure 5 whereupon the oil will flow through the passageway 99 down into the pressure chamber 46.

During periods of time when the engine" is stopped, the bearing member 47 will collapse against the reaction member '54 to the position of Figure 4, if the engine is stopped with corresponding engine valve 15' open. When the engine starts, oil is pumped from the pressure system into the reservoir 83' and will quickly fill into the pressure chamber 46. To permit this rapid filling, the valve supporting spring 82 will compress to permit the valve ring 92 and its valve spring 96 to move completely away from the groove 94 for a rapid .flow of oil. This position is shown in Figure 6, and it will be seen that valve ring 92 .can open much further when the spring 82 is compressed, than when only the spring 96 is compressed, as is the case in Figure 5.

To supply .oil to the reservoir 88, oil flows up through theraxial oiLsupply bore 44 in the center of the post 38 and outwardly through the lateral passages 100, which extend laterally through the top of the post tocommunicate between the central bored passageway 44 and the small chamber 102 .formed between the post 38 and the top of a tubular extension .104 which projects upwardly from the top of the .bearingmember v47. The-oil will normally flow over the top of the tubular extension 104 when the .parts are in the position of Figure 3, whichis the operating position. .Av series of rounded notches 106 are cut in the top edge of the tubular extension 10.4 so that oilcan flow over the top of this tube when the parts are collapsed, asshown in Figure4, due .to' the-:engin'e beingstopped with;a correspondingengine valve. 15.open. The oil then flows over the top of the flange orwall 86 of the sleeve 84 through the curved notches 10'8'ii1 the top of the wall to thus enter the oil reservoir 881 The first pressurized'oil that reachesthe adjuster after prolonged shut down of the engine contains quantities'of entrained air. The present invention prevents the air impregnated oil from entering the high pressure dham'ber ofthe adjuster and means are provided'jtoremove theair.

., i for this purpose, the small chamber 102, which intercepts't he oil before it reaches the reservoir or the pressure chamber, has a communicating vent 110. This vent re eeives thebubbles of air which rise from the oil in the reservoir 88 and flow out'through the vent 110. The vent is formed by the space between the threads 68 of the post and the opening 58 at the top of the reaction barrel 54. The vent is completed by a slot 112 through the side of the washer 66. If no washer is used, the slot will be found in the lower face of the nut. This vent is sufficiently small to prevent the escape of an appreciable amountof oil, but permits the escape of the bubblesof air and prevents them from reaching the pressure chamber 46. Theoil that does escape duringrunning operation runs down over the outside of the adjuster 36 and lubricates the surface 52 of the bearing member.

The small intermediate chamber 102 also co mmunicates with the oil leak-down path 50 which is formed between the inner surface of the bore 48 through the bearingmember 47 and the outer cylindrical surface 44 of the 'post38. This space or path is completed'by the tubular extension 104 which projects upwardly from the base of the bearing member 47.

When the engine valve stem 14 is being pushed downwardly by the push rod 32 being raised, the pressure within the pressurechamber 46 becomes greater than the pres sure within the engine oil system, which is the pressure within the reservoir 88. The valve ring 92 closes but a controlled escape of oil is permitted through an oil escape path 114 defined between the outer surface of the tube 104 ahdthe inner surface of the sleeve 84. This slow escape or bleed of oil is not 'suflicient to permit the parts to-collapse and the rocker arm will be held downwardly by the oil within the pressure chamber 46. When the engine valve closes, the pressure in the pressure chamber '46 will drop below the pressure within the oil system of the engine so that a replenishing supply'of oil is fed the' pressure chamber past the valve ring 92. In Figure 7 another form of the unitary fulcrum adjuster is shown at 36a. The fulcrum adjuster unit is illustrated as carried at the top of a post 38a which'may or may not be bored with a central oil passageway for supplymg oil to the fulcrum adjuster. In the form illustrated,

the adjuster has no external source of oil and operates from a fixedsupply contained within the reservoir 88a.

The adjuster includes a bearing member 47a which pivotally supports the rocker arm 25a and which is slidably mounted on the post 38a. The inner surface, 48a of the bearing member slides against the outer surface 44a of thepost. I

An oil pressure chamber 46a is defined between the bearing member 47a and a reaction member 54a. The reaction member has a cylindrical shaped barrel 55a which turned inwardly at its top 57a to form -a cupshaped element. The'barrel is staked as at 72a to catch beneath the flange 77a on the bearing member 47a to hold thebarrel 55a and bearing member 47a together.

The barrel 55a contains a central threaded opening 116 which permits the barrel to be threaded onto the top 68a of the post. Thus, the position of the fulcrum adjuster unit can easily be controlled by threading the entire barrel 55a up or down on the post.

The oil reservoir 88a communicates with the pressure chamber 46a through oil-passageways 90a. Flow .of oil through the oil passageways is controlled by a valve ring 92a held in place by a wave spring 96a, which is carried on a support 98a that is held at the top .of the valve support'spring 82a. The pressure chamber is sealed by dynamic seal 74a and a small oil bleed path 114a -is provided between the tube 104a which extends upwardly from the bearing member and the annular sleeve 84a, which is fixed within the barrel 55a. I

Thus, as the engine valve-is opened and the pressure withinthe pressure chamber 46a increases, a small leakin Figure 6.

This oil is replaced in the"press'ure chamber 46divhcn the engine-valve closes, by the oil being forced downwardly 'through the passageways a past the ring valve 92a.

Oil pressure is maintained within the reservoir 88a by aspring backed reservoir seal 118. This seal 118 is located slidably between the inner cylindrical surface 56 of the barrel 55a and the outer cylindrical surface of the tube 10411. The seal has an annular backing ring A coil compression spring 122 extends between the backing ring 120 and the top of the barrel 57a, thus maintaining a pressure within the reservoir 88a.

Thus, the unit of Figure 7 is entirely self-contained and requires no external supply of oil.

Although the operation of the fulcrum adjuster in combination with the valve linkage will be clear from the description of the individual elements, a brief sum-1 many of operation will be helpful in understanding the features and advantages. The fulcrum adjuster or lash preventing unit 36 is shown in its collapsed position in Figure 4, as it will appear after a shut down period of the engine if the engine stopped with the engine valve 15 open. The tube 104 engages the upper end 57 of the barrel 55 of the reaction member 54. When the engine is started, oil will flow upwardly through the central bored passageway 44 of the post 38 and outwardly through the lateral passageways 100. The pressurized' oil will pass through the curved notches 106 at the top of the tube 104 and through the notches 108 'at the top of the sleeve insert 84 to enter the reservoir by the slot 112 in the washer 66. Thus, air-free oil will pass downwardly into the passageways 90 to the pressure chamber 46. s

Upon starting, the oil will quickly fill the pressure chamber 46 by forcing the ring valve 92 away from the groove94, compressing spring 82 in the manner shown When the pressure chamber 46 is filled, and during operation, as the rocker. arm 25 is rocked to open the engine valve, the valve ring 92 will close and a small bleed of oil will flow upwardly through the annular path 114. When the engine valve stem is released, the pressure in the pressure chamber 46 will drop below the pressure in the reservoir 88 and a replenishing supply of oil will flow through the passageways 90 past the ring valve 92. Thiscycle of operation continues for each opening and closing of the valve and the rocker arm. will be supported to pivot about its fulcrum, as established by the bearing member 47.

Thus, it will be seen that I have-provided an improved fulcrum adjuster which operates to prevent objectionable valve lash and which-meets the objects and advantages hereinbefore set forth. The adjuster forms a unitary cartridge which is self-contained and is easily assembled on the engine. Adjustment of the position of the adjuster is easily obtained by threading the adjuster itself to the'top of a supporting post or by threading the nut onto the poston top of the adjuster.

The adjuster is provided with an annular oil bleed or leakage path from the pressure chamber to maintain a movement of oil through the pressure chamber during the operation of the mechanism. The lubricating oil leak-down path is also annular in shape and smaller in age of oil passes upwardly through a bleed path 114a. fl prevented from reaching the pressure chamber.

I have, in he d ng nd p cifica ion pre n ed a detailed disclosure ofthe preferred embodiments of my invention, but it is to be understood that I assist in tend to limit the invention to the specific form disclosed, butuntend to. cover all modifications, changes, and alternatrve constructions and methods falling within the scope of the principles taught by my invention.

I claim as my invention: 1. A lash preventing device for a valve operating linkage having a bearing surface for pivotally supporting a rocker arm whereby the rocker arm is held in non-lash engagement with its operating push rod and operated valve stem comprising a bearing member adapted to pivotally support a valve rocker arm, a reaction memher having a hollow cylindrical interior for slidably receiving the bearing member and defining an oil pressure chamber within the interior whereby the bearing memher is urged in a direction to prevent valve lash, a sup porting post extending upwardly from the engine and passing through the bearing member whereby the bearing member slidably reciprocates on the post, a narrow cylindrical oil escape passageway defined between the hearing member and the reaction member and communicating with the pressure chamber for the controlled escape of oil when the rocker arm exerts a pressure on the bearing member, an oil supply passageway leading to the pressure chamber for the supply of oil to the pressure chamber for replenishing oil lost through the escape passageway, and, valve means in the oil supply passageway preventing the escape of oil when the engine valve is being opened and the rocker arm exerts a reaction force on the bearing member and opening the valve to permit replenishing oil to the pressure chamber when the engine valve is closing and the reactive force between the rocker arm on the bearing member diminishes.

2. A device for preventing lash in engine valves operated by a rocker arm comprising a rocker arm support having a bearing for pivotally carrying the rocker arm, a reaction member cooperatively forming an oil pressure chamber with said rocker arm support for urging a rocker arm carried by the support into lash preventing engagement with its push rod and valve stem, a threaded post projecting from the engine for carrying the reaction mem ber, and threaded means coacting with the post and adjustably fixing the position of the reaction member and located in a fixed location relative to the post for each adjusted operating position of the reaction member, the threads otsaid post extending beyond. said threaded means a substantial distance whereby adjustment may be made beyond said operating positions.

3. A device for preventing lash in engine valves operated by a rocker arm comprising a rocker arm support having a bearing for pivotally carrying the rocker arm, a reaction member support cooperatively forming an oil pressure chamber with said rocker arm support for urging a-rocker arm cairied by the support into lash preventing engagement with its push rod and valve stem, a post extending through 'said members from the engine, biasing means urging the members apart, and a nutthreaded to the post and bearing against one of said members whereby said member may be adjustably positioned with respect to the other member.

4. A mechanism for pivotally supporting an engine valve rocker arm in non-lash relationship to coacting operating parts comprising a bearing member adapted to pivotally support a rocker arm, a cooperating reaction member coacting with the bearing member, with the surfaces of the reaction member and bearing member defining a pressure chamber therebetween urging the rocker arm to non-lash position, said surfaces also defining a closed reservoir in communication with the pressure chamber whereby a supply of oil will be available, and

,means to carry the reaction member in an operating position.

5. A mechanism for pivotally supporting an engine valve rocker arm in non-lash relationship "to coacting operating parts comprising a bearing member adapted to pivotally support a rocker arm, a cooperating reaction member coacting with the bearing member and the surfaces of the reaction member and bearing member defining a pressure chamber therebetween for urging the rocker arm to non-lash position, conduit means 'for supplying pressurized oil to the pressure chamber to force the members apart, and vent means communicating with the conduit means whereby air entrained in the oil is permitted to escape.

6. A mechanism for pivotally supporting an engine valve rocker arm in non-lash relationship to coacting operating parts comprising a bearing member adapted to pivotally support a rocker arm, a cooperating reaction member coacting with the hearing member and the surfaces of thc reaction member and bearing member dc fining a pressure chamber therebetween for urging the rocker arm to a non-lash position, means defining an oil supply reservoir communicating with the pressure chamber, and a vent passageway in communication with the reservoir whereby the air in oil supplied to the reservoir may escape.

7. A device for preventing lash in engine valves operated by a rocker arm comprising a rocker arm support having a bearing for pivotally carrying the rocker arm, a reaction member support cooperatively forming an oil pressure chamber with said rocker arm support for urging a rocker arm carried by the support into lash preventing engagement with its push rod and valve stem, means secured to the post and cooperating with the reaction member holding it in operation position, and passageway means defining a vent past the post to permit the escape of air bubbles entrained in the oil.

8. A device for preventing lash in engine valves operated by a rocker arm comprising a rocker arm support having a bearing for pivotally carrying the rocker arm, a reaction member support cooperatively forming an oil pressure chamber with said rocker arm support for urging a rocker arm carried by the support into lash preventing engagement with its push rod and valve stem, means securing the reaction member to the post, an oil pressure conduit communicating with the pressure chamber, and an oil leakage passageway defining means forming an oil passageway from the pressure conduit past the post whereby a small amount of oil escapes to lubricate the bearlugs.

9. A valve lash preventing device comprising a first and second support member for pivotally carrying a rocker arm for an engine, said support members defining an oil pressure chamber between them, a source for supplying oil pressure to said pressure chamber, an oil delivery conduit connecting between said oil source and said pressure chamber, and air removing means located between the pressure chamber and said oil source removing air entrained in the oil before it reaches the pressure chamber.

10. A valve lash preventing device comprising a first and second support member for pivotally carrying a rocker arm for an engine, said support members defining an oil pressure chamber between them, a source for supplying-oil pressure to said pressure chamber, an oil delivery conduit connecting between said oil source and said pressure chamber, a post supporting one of said members in operating position, and an annular leak down passageway between the post and member supported thereby for lubricating the valve operating gear, said passageway communicating with the 'oil delivery conduit for the delivery of oil to the bearing surface of the rocker arm.

11. A valve lash preventing device comprising a first and second support member for pivotally carrying a rocker arm for an engine, said support members-defining as'ra'rsu an oil pressure chamber between them, a source for supsingle dynamic seal between said support members whereby a minimum of restriction is ofiered to relative movement therebetween for rapid response with various oil viscosities.

12. A valve lash prevention assembly comprising a bearing member having a cylindrical outer surface adapted to pivotally support a rocker arm in engagement with a push rod and a valve stem, at second reaction member forming an interior cylindrical surface for receiving the bearing member therein and coacting with the bearing member to form an oil pressure chamber, a support member adapted to carry the reaction member in an operating position, and means delivering oil under pressure to said oil pressure chamber.

13. A valve lash prevention assembly comprising a bearing member having a cylindrical outer surface adapted to pivotally support a rocker arm in engagement with a push rod and a valve stem, a reaction member, forming an interior cylindrical surface for receiving the bearing member to be slidably positioned therein and coacting with the bearing member to form an oil pressure chamber, a support member adapted to carry the reaction member in an operating position, and adjustment means connected to the reaction member and threaded to the support member whereby the position of said member may be adjusted.

14. Av valve lash prevention assembly comprising a bearing member having a cylindrical outer surface adapted to pivotally support a rocker arm in engagement with a push rod and a valve stem, a cup shaped reaction member having a cylindrical interior for slidably receiving the bearing member and extending over the top of the hearing member with an opening through the top and coacting with the bearing member to form an oil pressure chamber, a supporting post adapted to be mounted on an engine and projecting through the opening at the top of the reaction member, means for securing the reaction 10 member to the post, and mean: for delivering oil to the pressure chamber.

15. A valve lash preventer operable through a first stage when an engine valve is being opened and a second stage when the valve is being closed, comprising a bean ing member adapted to be connected to pivotally support an actuated rocker arm, a reaction member forming an oil pressure chamber with the bearing member, an oil escape path communicating with the pressure chamber permitting a controlled escape of oil when an engine valve is being opened in the first stage and the rocker arm exerts a force on the bearing member, and an oil replenishing path communicating with the pressure chamber for the replacement of oil lost through the escape path and feeding oil to the pressure chamber in the second stage when the valve is being closed.

16. A valve lash preventing device comprising a unitary supporting cartridge having a rocker arm carrying member adapted to be connected to pivotally support the rocker arm, means for holding the supporting cartridge in operating position relative to an engine, pressure chamber elements forming an expansible oil pressure chamber operatively connected to the carrying member, means forming an oil supply reservoir connected to the pressure chamber, and means within the supporting cartridge maintaining a pressure within the reservoir to maintain an operating pressure in the pressure chamber.

17. A device for preventing lash in engine valves operated by a rocker arm comprising a rocker arm support having a bearing for pivotally carrying the rocker arm, a reaction member cooperatively forming an oil pressure chamber with said rocker arm support for urging a rocker arm carried by the. support into lash preventing engagement with its push rod and valve stem, at post projecting from the engine to carry said reaction member, and means adapted to be secured to the post whereby the position of the reaction member is determined with respect to the post.

References Cited in the file of this patent UNITED STATES PATENTS 2,718,219 Chayne et a1. Sept. 20, 1955