US2971503A - Fulcrum adjuster - Google Patents

Description

Feb. 14, 1961 J. w. SCHNABEL FULCRUM ADJUSTER 2 Sheets-Sheet 1 Filed April 22, 1959 M 5 H ,5 kW ..w

r l! A Feb. 14,1961 2,971,503

J. W. SCHNABEL FULCRUM ADJUSTER Filed April 22, 1959 2 Sheets-Sheet 2 Jullus W Schnabel Unite FULCRUM ADJUSTER Filed Apr. 22, 1959, Ser. No. 808,178

12 Claims. (Cl. 123-90) This invention relates to improvements in lash adjusters for engine valve linkage, and more particularly to an improved oil operated valve lash adjuster which is mounted on the head of a valve-in-head engine, and operates under pressure of the oil from the engine oil supply system to hold the rocker arm against the valve stem and push rod and take up play which occurs in the linkage The present invention contemplates the provision of a lash adjuster for use with a lightweight metal rocker arm having a fragmental, spherical, depressed portion with an opening receiving a mounting stud or post anchored in the engine head. A bearing member with a hemispherical end supportingly engaged in the fragmental, spherical, depressed portion of the rocker arm is slidable on the post and holds the rocker arm in non-lash engagement with a push rod and a valve stem against which the rocker arm engages. The bearing member is integral with a housing having an elongated bore defining a cylinder in which a piston member is slidably mounted to form an oil pressure chamber between the housing member and piston member. A plurality of radially and downwardly extending inclined oil passages extend through the piston from an oil supply chamber within the piston to deliver oil to the pressure chamber and a return flow preventing valve means in the form of a spring biased ring engaging the open end of the passages prevents the return flow of oil from the pressure chamber to the supply chamber. Oil is furnished to the supply chamber from the oil pressure system of the engine, such as by an oil bore extending through the post and leading to the supply chamber. Air is permitted to escape from the oil by an oil vent passage means extending from the oil supply chamber through the piston and opening exteriorly of the piston. An oil seal ring of flexible material surrounds the post at the base of the pressure chamber and has an inclined upper face with a mating ring engaging the inclined upper face to press the flexible ring into sealing engagement with the outer surface of the post.

An object of the present invention is to provide an improved lash adjuster mechanism which obtains advantages States Patent in operation and manufacturing cost over mechanisms heretofore used, and obtains a long wearing life and reliability of operation.

Another object of the inventionis to provide an improved lash adjuster mechanism with-an improved oil leakage path which reduces the possibility of clogging the passages.

Another object of the invention is to provide a means for eliminating or digesting any possible air that might be induced into the high pressure oil chamber,

Another object of the invention is to provide an improved mechanism or" the type described having a reduced number of required high pressure oil seals.

Another object of the invention is to provide a lash adjusting mechanism wherein the operating clearances are simple and avoid the necessity of providing areasjof close manufacturing tolerances heretofore necessary, and

provide an adjuster with fewer manufactured components;

Another object ofthe invention is to provide a valve 2 lash adjuster in which a high pressure sealing means is provided which is of a small diameter and will aid in reducing the inherent drag thereby obtaining a quicker recovery speed during starting and low temperature operation.

Another object of the invention is to provide an adjuster with an improved oil delivery to the pressure chamber under both starting and running conditions, and wherein a controlled escape of oil is permitted from the pressure chamber during a valve opening stage of operation with the positive replenishment of oil during the valve closing stages of operation.

Another object of the invention is to provide a valve lash adjuster that can be supplied with oil either from the top of the adjuster or from an oil gallery up through a central hole in a supporting post.

A still further object of the invention is to provide a means for storage of oil so that oil will not drain from the adjuster during periods when the engine is not running.

Other objects and advantages will become more apparent with the teaching of the principles of the invention in connection with the disclosure of the preferred embodiments thereof in the specification, claims and drawings, in which:

Figure l is a vertical sectional view taken through a valve operating linkage provided with an adjuster mechanism. in accordance with the principles of the present invention;

Figure 2 is an enlarged vertical sectional view taken through the axis of an adjuster mechanism having features ing parts of the high pressure seal mechanism;

Figure 4 is a vertical sectional view taken through the axis of another embodiment of the adjuster mechanism of the present invention;

Figure 5 is a horizontal sectional view taken substantially along line V-V of Figure 4;

Figure 6 is a horizontal sectional view taken substantially along line VI-VI of Figure 4; and,

Figure 7 is a vertical sectional view taken through the axis of the valve adjusting mechanism illustrating another embodiment of the invention.

As shown on the drawings:

As illustrated in Figure 1, an internal combustion engine is shown generally at it} and includes a cylinder block 11 and a cylinder head 12. The head 12 has a guide 13 receiving in slidable relation therein the stem 14 of the poppet valve 15. y The head 16 of the valve 15 cooperates with the seat 17 in the engine head 12 to control the flow between the valve port 18 and the head 12 in the combustion chamber 19.

The upper end of the valve stem has grooves 20 thereon and the conventional split valve locks 21 have beads seated in these grooves. A valve spring retainer 22 is fixedly held on the upper end of the valve stem by locks 21 and a valve spring 23 surrounds the valve stem and has one end bottomed on the retainer 22 and the other end bottomed on a shoulder 24 of the engine head 12 surrounding the guide 13. The valve stem 14 is thus have a generally bowl-shaped interior 29. At one end of the rocker arm and on 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

7 push rod end 31 can rock in the socket 30 and an oil aperture 33 is provided through the socket to lubricate 3 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;

In accordance with this invention, the rocker arm is mounted on the engine head 12 by means of an automatic lash adjuster shown generally at 36. The lash adjuster 36 includes a housing member 3'7 which is provided with an upstanding tubular Wall 38 having a cylindrical inner surface or elongated bore 38a to form a cylinder therein for slida-bly receiving a piston 39. The bore or cylinder 38a forms a pressure chamber iii which is closed by the piston 39.

At the base of the housing 37 is a bearing 37:: having a fragmental spherical surface slidably seated in the depressed portion 26 of the rocker arm to thereby support the rocker arm in non-lash engagement with the upper end of the push rod 32 and the upper end of the valve stem 14. A circular opening 41 is formed in the lower end of the housing and through this opening extends a post 42 having a smooth outer surface 43 at the location where it passes through the opening 41 and being threaded at its lower end 44 for mounting on the head 12 of the engine. The engine is provided with a pressurized oil gallery 45 and an oil bore 46 through the axial center of the post 44 communicates with the oil gallery. 7

Within the piston is an oil supply chamber 47 formed by a bore extending from the top of the piston and the oil bore 46 through the post continues through the piston to communicate with the supply chamber 47.

Pressurized oil flows from the supply chamber through a plurality of inclined radially downwardly extending circurnferentially spaced passages, such as illustrated at 38 and 49, which lead into the pressure chamber at The passages open into an annular groove i), and back- ,fiow from the pressure chamber is prevented by a return iiow preventing valve means in theform of an annular ring 51 biased upwardly against the groove 50 by a coil compression spring 52. I V

The pressure chamber 40 is sealed with respect to the post 42 by a ring 5 of flexible resilient material. A rigid ring 53 is positioned above the flexible ring 54, and is urged downwardly and provides a support for the spring 52. These rings are shown in detail in Figure 3, and the flexible ring has a cylindrical inner surface 54a and a flat base 54b for seating in the bottom of the pressure chamber 4% The ring 54 has an upper inclined surface 540 which leads from its thinner outer edge to a thicker inner edge and coact's with a mating inclined surface 53b on the rigid ring 53. The ring 53 has a circular inner opening 53:: to slidably fit on the'post and has a fiat upper surface 53c for supporting the spring 52'. r

' The upper end of the bore which extends downwardly into the piston and provides the supply chamber 47 is threaded at 55 and receives a threaded plug 56 which is provided with a socket 57 for receiving a tightening wrench. A small axial air vent 58 extends through the plug 56 for the escape of air thereby preventing air from being delivered to the pressure chamber lit. The air vent opening 53 also provides afiow of oil during operation of the engine. Entrapped air may also' escape from the high pressure chamber between the outer surface of the piston and the cylinder 38a. The annular passage formed in the space between the piston andcylinder controls the lealrdown rate from the pressurechamber 40.

[The embodiment 59, as illustrated in, Figure 2, shows a'strueture substantially the sameas Figure l, and means are provided to prevent the escape of oil fronrthe pressure chamber 47 after the engine is shut down and to provide a Well or reservoir of reserve oil. A standpipe 63 in the form of a short length of tube is secured to project upwardly and the hollow interior 63 forms an extension of the oil bore 46 for supplying oil under pressure to the supply chamber when'the engine is shut down, and the pressure drops in the bore 46, the standpipe will prevent oil from draining from a reservoir 64 in the annular space surrounding the standpipe and this reservoir will maintain an oil reserve.

In the embodiment of Figure 4, an adjuster 66 employs a housing 37' similar to the housings for the 'adjusters in Figures 1 and 2. The housing is provided with an inner bore or cylinder 33a, as formed by the w-all'38, to slidably receive a piston d7. Centrally located within the piston is an oil supply chamber 68, which is formed from a bore extending from the upper end of the piston. The upper end of the here is threaded at 69 to receive a threaded fitting 71 which is adapted to connect to an oil supply line '72. Thus, the oil in the embodiment illustrated is supplied from the top of the adjuster 66. The piston is rigidly supported with respect to the valve linkage and to the engine by a post 74, which is not provided with an oil supply bore. Pressurized oil from the oil supply chamber as ilows downwardly to the pressure chamber 4% through a plurality of circumferentially spaced downwardly radially extending passages 73. These passages open from the oil supply chamber 68 at their upper ends 73a (Figures 4 and'i), and open from their lower ends 731;,(Figures 4 and 6) into an annular channel '76. The channel 76 faces downwardly and opens from a flat surface 7'? at the base of the piston. This ilat surface provides a valve seating surface for the valve ring it which is held in closed position by the spring 52, and which will be forced downwardly to permit the flow of oil into the pressure chamber when the force on the rocker arm is released by downward movement of the tappet rod 32 of Figure l. i

in the adjuster 78, shown in Figure 7, the housing 38' provides the cylinder 33a which slidingly receives a piston 79. The piston'is supported on a' post 81, mounted on the engine head, and the post has an axial oil bore 82, extending upwardly and continuing part way into the piston Leading radially outwardly and downwardly from the upper end of the oil bore 32 are a plurality of passages 85 which open into a channel or a groove 84 facing downwardly from a surface 86 on the piston. The reverse flow preventing valve ring d1 seats on the surface 556 and prevents the backfiow of oil from thepressure chamber into the bore fi which serves as a supply chamber. i i

Extending'upwardly from the upper end of the bore is an air vent passage 88 which opens from the upper surface 87 of the piston to vent air from the oil to atmospheric pressure and to permit a slow escape of oil during operation of the engine.

As a summary or" operation of the adjuster, as illustrated inFigure 2, during shut-down periods of the engine, a supply of oil will be contained in the reservoir 64 surrounding the standpipe sift, inasmuch as the oil cannot flow back into the oil bore 46. started, a pressurized suppiyvof oil will' flow upwardly through the bore 46 and into the oil supply chamber 47 with air escaping through the air vent passage 58,. A controlled escape of oil will also flow from .the supply chamber through the passage 58 during operation of the engine. Oil will flow downwardly through the radial passages 43 and 4% into the pressure chamber to urge the bearing 3% into non-lash supporting engagement with the rocker arm 25. The backflow of oil through the passages will be prevented by the valve ring 51, and a controlled escape of oil from the pressure chamber will be permitted by the annular clearance between the piston 39. and the housing wall 3% with the leakage being replenished each timetheforce on the rocker arm on the housing isreleased by the push rod.

.Thus it will be seen that I have provided improved When the engine is and practical valve lash adjuster which obtains the advantages and objectives above set forth.

I have, in the drawings and specification, presented a detailed disclosure of the preferred embodiments of my invention, and it is to be understood that I do not intend to limit the invention to the specific forms disclosed, but intend to cover all modifications, changes and alternative constructions and methods falling within the scope of the principles taught by my invention.

I claim as my invention:

1.A valve lash adjuster for a valve linkage including a rocker arm for operating a valve for an engine having a pressurized oil supply system, the lash adjuster comprising a bearing member having a surface for supporting engagement with an engine rocker arm to hold the rocker arm in non-lash relationship with a valve, a cylinder formed by a wall having a cylindrical interior surface to form a pressure chamber with an upper open end and being connected to said bearing member, a piston slidably housed in said cylinder and closing the upper open end of the pressure chamber, a support member connected to said piston for rigidly positioning it relative to the engine in which the lash adjuster operates, means defining a centrally located oil supply chamber within the piston, an oil supply conduit means connected to said oil supply chamber for delivering pressurized oil from the engine supply system to the chamber, a plurality of radially downwardly inclined passages extending through and circumferentially spaced around the piston and communicating between said oil supply chamber and said pressurechamber, and return flow preventing valve means connected to said passages for preventing the flow of oil from said pressure chamber to said oil supply chamber so that the bearing member will be operated by pressurized oil to prevent lash of the engine rocker arm.

2. A valve lash adjuster for a valve linkage including a rocker arm for operating a valve for an engine having a pressurized oil supply system, the lash adjuster comprising a bearing member having a surface for supporting engagement with an engine rocker arm to hold the arm in non-lash relationship with a valve, :1 cylinder formed by a tubular wall extending integrally upwardly from said bearing member and forming a pressure chamber therein with an upper end open, a piston slidably housed in said cylinder closing the pressure chamber, a supporting post connected to the piston extending downwardly through an opening in said cylinder for rigidly supporting the piston with respect to the engine, a cylindrically shaped opening extending downwardly from the top of the piston, a threaded plug turned into said opening and forming a supply chamber within the piston, oil conduit means extending through said post and communicating with said oil supply chamber for supplying oil thereto from the pressurized engine oil supply system, a plurality of radially downwardly inclined passages ,through the piston communicating between said oil supply chamber and said pressure chamber, and a return flow preventing valve means connected to said passages for preventing the ilow of oil from said pressure chamber to said oil supply chamber so that the bearing member will be operated by pressurized oil to prevent lash of the engine rocker arm.

3. A valve lash adjuster for a valve linkage having a rocker arm for operating the valve for an engine having a pressurized oil supply system, the lash adjuster comprising a bearing member having a surface for supporting engagement with an engine rocker arm to hold the arm in non-lash adjustment with a valve, a tubular wall integral with said bearing member extending upwardly therefrom to form an oil pressure chamber cylinder therein with an upper end open, a piston slidably housed in said cylinder and closing the open upper end of the pressure chamberga support post extending downwardly through said bearing member and connected to the piston for rigidly positioning it relative to the engine in which the lash adjuster operates, oil supply conduit means extending through said piston and communicating with said pressure chamber for delivering oil from the engine supply system to the pressure chamber, return flow preventing check valve means in said pressure chamber connected to said oil supply conduit means for preventing the return fiow of oil from said pressure chamber, resilient oil seal means between said post and said bearing member to prevent the leakage of oil from said pressure chamber, and a spring in said pressure chamber at one end urging said check valve to closed position and at the other end resiliently urging said oil seal means into sealing engagement with said post and said bearing member.

4. A valve lash adjuster for a valve linkage including a rocker arm for operating a valve for an engine, the lash adjuster comprising a housing member having an elongated bore, a piston member slidably mounted in said bore with a pressure chamber formed between said piston and said housing member within said bore, a post extending upwardly through an opening in said housing member and connected to the piston member for supporting the piston member in a fixed position relative to an engine in which the valve adjuster operates, a hearing secured to the housing member and pivotally carrying the valve rocker arm to urge the rocker arm to nonlash engagement with an engine valve, conduit means for delivering pressurized fluid to said pressure chamber to urge said bearing against said rocker arm so that lash is prevented, a check valve in said chamber connected to said conduit means, a resilient ring within said pressure chamber surrounding said post to form a slidable seal against the post preventing leakage of oil from the pres sure chamber along the post, said ring having a tapered upper surface with the taper extending from a thicker inner edge of the ring to a thinner outer edge, a mating rigid ring having a tapered surface corresponding to the tapered surface of the resilient ring and positioned above said resilient ring, anda coil compression spring in said chamber surrounding said post engaging said check valve at its upper end to hold the valve closed and resting on said rigid ring at its lower end biasing said rigid ring downwardly toward said resilient ring for urging the resilient ring to scaling engagement with said post.

5. A valve lash adjuster for a valve linkage including a rocker arm for operating a valve for an engine having a pressurized oil system, the lash adjuster comprising a housing member having an elongated bore, a piston member slidably mounted in said bore with a pressure chamber formed between said piston member and said housing member within said bore, means supporting said piston member in a fixed operating position relative to the valve linkage, a bearing for pivotally carrying the valve rocker arm secured to said housing member to urge the rocker arm to non-lash engagement with an engine valve,

means defining a supply chamber within said piston,

means defining a plurality of passages extending radially outwardly and downwardly from said supply chamber and opening into said pressure chamber for the delivery of pressurized engine oil to said pressure chamber to urge said bearing against said rocker arm whereby lash is prevented, returnflow preventing valve means connected to said passages for preventing the backflow of oil from said pressure chamber to said oil supply chamber, and a elongated bore, a piston member slidably mounted in said bore with a pressure chamber formed between said piston member and said housing member within said bore, means supporting one of said members in a fixed operating position relative to the valve linkage, a hearing for pivotally carrying the valve rocker arm secured to the other ofsaid members to urge said rocker arm to non-lash engagementwith an engine valve, means, defining an oil supply chamber within said piston member,

a passage extending from said oil supply chamber through said piston member to said pressure chamber, a return flow preventing valve means connected to said passage for preventing the flow of oil from said pressure chamber to said supply chamber, an oil supply conduit means connected to said supply chamber for delivering pressurized oil from an engine supply system to the supply chamber, return flow preventing valve means connected to said passage for preventing the flow of oil from said pressure chamber to said oil supply chamber, and reservoir forming means preventing the return of a quantity of oil from said supply chamber through said supply conduit means for forming a reservoir of oil between said reservoir means and said return flow preventing valve means to supply said pressure chamber.

7. A valve lash adjuster for a valve linkage including a rocker arm for operating a valve for an engine, the lash adjuster comprising a housing member having an elongated bore for operation with the bore extending vertically, a piston member slidably mounted in said bore with a pressure chamber formed beneath the piston in said housing member bore, means supporting said piston member in a fixed operating positionrelative to an engine, a bearing for pivotally carrying the valve rocker arm secured to said housing member to urge the rocker arm to non-lash engagement with an engine valve, means defining a supply chamber within said piston member, means defining a passage through said piston member communicating between said supply chamber and s id pressure chamber, an oil supply conduit means ext nding upwardly through the piston member and opening into said supply chamber, and a tubular standpipe extendnig upwardly-from said oil supply conduit means and forming a reservoir of oil outwardly of; said standpipe which is retained during non-operating periods of the engine to provide a supply for said pressure chamber.

8. A valve lash adjuster for a valve linkage including a rocker arm for operating a valve for an engine, the lash adjuster comprising a housing member having an elongated bore for operation with the bore extending vertically, a piston member slidably mounted in said bore with a pressure chamber formed beneath the piston in em- .ber in saidhousing member bore, means supporting said means defining a passage through'said piston member communicating between said supply chamber and said pressure chamber, an oil supply conduit means extending upwardly through the piston member and openi into said supply chamber, a tubular standpipe extend g upwardly from said oil supply conduit means and forming a reservoir of oil outwardly of said standpipe which is retained durin non-operating periods of the engine to provide a supply for said pressure chamber, and means defining an air vent passage extending through the piston member and communicating with the upper end of said supply'chamber for the escape of air from the oil supply.

9. A valve lash adjuster for a valve linkage including a rocker arm for operating a valve for an engine, the

laslradjuster comprising a housing member having elongated bore, a piston member slidably mounted in said bore with a pressure chamber formed between said piston member and said housing member within said bore,

means supportingone of said members in a fixed operating position relative to the valve linkage, a bearing for pivotaliy carrying a valve rocker arm and secured to the other of said members to urge the rocker arm to non-lash supporting post adapted to be mounted on the engine and having an axially extending oil bore through said post, a bearing member for pivotaliy carrying the rocker arm and having an axially extending bore for slidably fitting the bearing member on the post, said bearing member having a cylindrically hoilow interior axialiy parallel with the post and ng an oil pressure chamber between the post and hollow interior, a p ton slidably mounted within the hollow bearing member interior and secured to the post to close the oil. pressure chamber, a supply chamber within said piston eonnectc to said oil bore, a pluraiity of radially extending passages leading from said supply chamber to said pressure chamber, return flow preventing valve means connected to said passages for preventing the return flow of oil from said pressure chamber, and an air vent passage means extending through said piston and opening from the exterior therof at the end of the piston opposite the location of said post so that air may escape from the oil. in the supply chamber.

ll. A vaive lash adjuster for a vaive linkage including a rocker arm for operating a valve for an engine, the lash adjuster comprising a housing member having an elongated bore, a piston member slio'aoiy mounted in said bore with a pressure chamber formed between said piston member and said housing member within said bore, means supper lg one of said members in a fixed operating position relative to the valve linkage, a bearing for pivotally carrying the vaive rocker arm and secured to the other of said members to urge the rocker arm to nonlash engagement with engine valve, an oil supply chamber within said on member, a passage extending through said piston her and communicating with said oil supply chamber and with said pressure chamber, an oil supply conduit connected to said supply chamber for the delivery of pressurized oil from the engine supply system of an en ine, and air vent passage means leading through said piston member from the supply chamber and opening exteriorly of said piston member for the escape of air induced into the supply chamber with oil.

12. A valve lash adjuster for supporting a pivotal rocker arm on an engine head provided with a pressurized oil system comprising, a supporting post adapted to be mounted on the engine and having an axially extending oil bore through said post,a bearing member for pivotally carrying a valve rocker arm a bore for slidably fitting the bearing member on the post, said bearing memher having a cylindrically hollow interior axially parallel vith the post and defining an oil pressure chamber between the post and hollow interior, a piston slidably mounted within the cyiindrically hollow bearing member interior and secured to the post to close the oil pressure chamber, said piston having an oil bore extending axially part way though the piston and forming an extension or said oil bore in said post, a passageway extending from said oil bore in the post and communicating with said oil pressure chamber, and an air vent passage of a size substantiaily smaller than said oil bore in said piston extending from said piston oil bore through the piston and opening at the end thereof for the escape of air from oil flowing through said oil bores.

References Cited in the file of this patent UNITED STATES PATENTS Hagadone .Q. Dec. '22, 1959

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