US2853984A

US2853984A - Hydraulic valve lash adjuster

Info

Publication number: US2853984A
Application number: US570271A
Authority: US
Inventors: Sampietro Achilles Charles
Original assignee: Thompson Products Inc
Current assignee: Northrop Grumman Space and Mission Systems Corp
Priority date: 1956-03-08
Filing date: 1956-03-08
Publication date: 1958-09-30
Anticipated expiration: 1975-09-30

Description

Sept. 30, 1958 A. c. SAMPIETROI 2,853,984

HYDRAULIC VALVE LASH ADJUSTER Filled March a, 1956 2 Sheets-Sheet 1 222221422? Abe /aw 55m JIM/am Sept. 30, 1958 A. c. SAMPiETRO 2,853,984

HYDRAULIC VALVE LASH ADJUSTER United States Patent HYDRAULIC VALVE LASH ADJUSTER Achilles Charles Sampietro, Detroit, Mich., assignor to Thompson Products, Inc., Cleveland, Ohio, a corporation of Ohio Application March 8, 1956, Serial No. 570,271

22 Claims. (Cl. 123-90) This invention relates to improvements in lash adjusters for engine valve linkage. More particularly the invention relates to an improved oil operated valve lash adjuster which is mounted on the pivot post of the rocker arm of a valve-in-head engine valve linkage and operates under the pressure of the oil from the engine to hold the rocker arm against the valve stem and push rod and take up the play which occurs in the linkage.

The present invention contemplates a lightweight stamped, pressed, brazed, or otherwise fabricated metal rocker arm having a fragmental spherical depressed p0rtion and receiving a mounting stud or post anchored in the engine headin communication with the oil gallery. A bearing member with a hemispherical end is slidable on the post or stud to seat in the depressed portion of the rocker arm. The stud or post has an oil passage therethrough communicating with a passageway or a reservoir in the piston which communicates with the hollow interior or pressure chamber of the bearing member. A check valve accommodates the flow of oil from the piston to the bearing member pressure chamber but prevents reverse flow of oil. The bearing is thus held in bearing contact with the depressed portion of the rocker arm by oil pressure and the rocker in turn is urged into good bearing contact with the conventional push rod and spring loaded engine valve stem. Improved means are provided for enhancing the action of the bearing member, and for feeding oil to the bearing member.

An object of the invention is to provide an improved method and system of feeding oil from the pressurized oil gallery of the engine head to the pressure chamber of the valve lash adjuster.

Another object of the invention is to provide a valve lash adjuster of the type described which will have an increased wearing life and which will operate to insure that a film of oil is always present between the moving parts.

Another object of the invention is to provide a valve lash adjuster which will reduce the leak-by effects of the oil in reducing the pressure in the pressure chamber during operation.

Another object of the invention is to provide a valve lash adjuster which will decrease the operating noise of the valve linkage and of the lash adjuster especially when the engine is first being started.

Another object is to provide a valve lash adjuster which will provide a self-contained reservoir to provide a supply of oil for supplying oil to the pressure chamber at cranking speeds of the engine before the oil pressure is built up for normal operation.

A still further object of the invention is to provide a valve lash preventing mechanism which will feed oil to the mechanism in adequate quantities from the pressure gallery of the engine head with varying engine speeds from at cranking speed to high running speeds.

A general feature of this invention is to provide an automatic valve lash adjuster which has improved action ice and which is able to take advantage of the full effect of the pressure of the oil to perform its valve lash preventing operation.

Another object of the invention is to provide an improved valve lash adjuster in which the parts are more readily assembled and which are more simple and easy and inexpensive to manufacture.

Another object of the invention is to provide an improved valve lash adjuster with an improved check valve design which will prevent the oil from flowing back into the engine head gallery.

Another object is to provide a check valve for a valve lash adjuster which will pass oil at two different rates, a slow rate during cranking speeds when more time is available and a rapid rate at operating speeds when less flow time is available.

Further objects and advantages of the present invention will become' more apparent to those skilled in the art with the complete disclosure of the invention as described in connection with the specification and claims and drawings wherein like numbers are used to indicate like elements and in which:

Figure 1 is a vertical elevational view taken in section through the head of an internal combustion engine which is shown to illustrate the preferred embodiment of the present invention;

Figure 2 is a plan view of the valve lash adjuster and engine rocker arm viewed from the top of Fig. 1;

Figure 3 is a vertical sectional view taken along line III--III of Fig. 2 and illustrating in enlarged detail the internal construction of the valve lash adjuster mechamsm;

Figure 4 is a horizontal sectional view taken along line IVIV of Fig. 3;

Figure 5 is an enlarged detail view of an alternative form of a detailed portion of the structure of Fig. 3;

Figure 6 is an enlarged detail view in vertical section of an alternative embodiment of a valve that may be used to check the backflow of oil from the pressure chamber;

Figure 7 is another detail enlarged view in vertical section to show a valve design which may be used;

Figure 8 is another vertical sectional view similar to Fig. 3 but illustrating an embodiment employing alternative features of the invention;

Figure 9 is a sectional view taken along line IX-IX of Fig. 8; and

Figure 10 is an enlarged detail view taken in section of the spring arrangement used to control the check valve for preventing reverse flow of oil from the pressure chamber to obtain dual rates of flow.

While the figures of the drawings and the description illustrate the preferred embodiment of the invention, it is to be expressly understood the features, methods and objectives of the invention can be utilized in mechanisms of various types and that features of detail are to be taken as illustrative only and not by way of limitation.

In the embodiment illustrated in Fig. 1, the internal combustion engine is shown generally at 10, 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. The head 16 of the valve 15 cooperates with the seat 17 in the enginehead 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 a retainer 22 and the other end bottomed on a shoulder 24 of the engine head '12 suri 3 rounding the guide 13. The valve stem 23 is biased to hold the valve head 16 against seat 17.

A stamped sheet-metal rocker arm 25 has a depressed fragmental spherical socket portion 26 in the bottom thereof with an aperture 27 through the bottom 'of the socket. The rocker arm 25 is indicated in both Figs. 1 and 2 and is surrounded by an upturned peripheral flange 28 to 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 3% for the rounded end 31 of a push rod 33. The push rod end 31 can rock in the socket and an 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.

In accordance with this invention the rocker arm is mounted on the. engine valve head 12 by means of an automatic lash adjuster shown generally at 36.

The lash adjusting mechanism which is shown at 36 and which may be used in a valve linkage arrangement of the'type shown and described herein, is illustrated in combination with the valve in Fig. 1 and is shown in enlarged detail in Fig. 3 for better recognition of the general and specific structural details.

The lash adjuster mechanism includes a vertical upstanding post 38 which carries threads 40'at the lower end for purposes of threading into a threaded bore hole 42 in which the post is securely threaded. The bore hole 42 leads to the pressurized oil gallery 44 of the engine head which contains oil under pressure as provided by the oil pump of theengine.

Extending axially upwardly through the post is a bore hole 46 which is in communication with the oil gallery and which permits the oil to flow upwardly through the center of the post.

The post has a smooth cylindrical shank portion 48 which is in sliding engagement with the cylindrical bore 50 of the bearing member 52. The bearing member has a smooth semi-spherical socket portion 26 of the rocker arm 25 thus pivotally supports the rocker arm. The aperture 27 in the bottom of the socket portion of the rocker arm is sufiiciently'large to permit pivotal movement of the rocker arm without interfering with the post 38.

The bearing member 52 contains an enlarged cylindrical bore extending downwardly from the upper end coaxially with the axis of the post 38. The-inner wall 56 of the bore forms a cylinder for slidably containing the piston 58 which is suitably secured to the top end of the post 38. Although the thin wall 58 of the cylinder S6 is formed integral with the lower portion of the bearing member 52, it will be recognized that the tubular extension 58 which forms the cylinder could be formed of a separate part suitably secured, such as by welding to the lower portion.

For securing the piston'56 to the post '38 the piston carries internal female threads 60. The post at its upper end carries mating male threads 62 and in assembling the apparatus the piston is turned down onto the top of the post and a screw slot 64 in the top of the cylinder permits the piston to be turned-down firmly onto the post. A gasket 66 may be provided at the top of the post for preventing leakage of the oil down past the threads and 62. The gasket 66 of course carries a circular central hole to provide passageway of the oil upwardly through the axial bore hole 46 through the center of the supporting post 38.

Although the position of the supporting post 38 and the bearing member 52 and piston 56 are shown as being vertical it is to be understood that they will be operative in various other positions and the description of the location of the relative parts with respect to thevertical 4 position is to be taken as pertaining to the preferred example only and not as limiting.

The piston 56 is thus secured to the post and slides within the cylinder 57 of the bearing member 52 as the bearing member slides up and down with respect to the supporting post 38. This movement will occur when the pressurized oil chamber 68 is filled with oil usually from the pressure system of the engine. The oil is fed upwardly through the axial bore 46 in the post 38. The piston 56 seals the oil pressure chamber 68 and as pressure builds up therein it forces the bearing member 52 downwardly with respect to the post and connected piston to urge the rocker arm firmly down on top of the valve stem and the push rod.

To prevent excessive leak down of the oil from the pressure chamber 68 between the bearing member 52 and the supporting post 38 between the sliding surfaces 48 and 58, an annular groove 70 is cut into the bearing surface 50 within the bearing member 54 and in this groove is positioned an oil seal 72 shown in the form of an O-ring. This O-ring forms a gasket preventing the passageof excess oil down between the sliding surfaces.

To prevent oil escaping upwardly from the pressure chamber 68, the clearance between the piston 56 and the inner wall 57 of the cylinder is kept at a minimum. In addition to this, a constant stream or supply of pressurized oil is supplied between the two moving surfaces of the piston 56 in the cylinder 51. This pressurizing of the area between the piston and cylinder wall is accomplished by a lateral oil passageway 74 which extends horizontally across the center of the piston 56. To conduct oil to the lateral passageway a short vertical extension 76 of the axial bore 46 of the post is provided within the piston to thus channel the oil up through the axial. passageway 46 and into the lateral passageway 74. Thus while the engine is running oil flows outwardly through the lateral passageway to continually pressurize the surfaces between the piston and the cylinder, insuring 40 that the sliding surfaces will be moving with a film of trolled leak of oil over the upper edge of the'wall 58 to flow down into the hollow rocker arm and supply lubrication to the end of the push rod and to other operating parts. The pressurized oil also passes downwardly between the walls of the piston and cylinder to create a counterpressure from that provided by the oil within the oil pressure chamber 68 within the bearing. This counterpressure reduces leakage of the oil from the oil pressure chamber and increases the speed of build up of pressure within the chamber when the engine is started. Further the oil which does leak upwardly between the piston and cylinder well does not first have to pass through the pressure chamber.

In order to improve the distribution of oil flowing through the lateral passageways 74 and insure that the entire space between the piston 56 and the cylinder wall 58 will be filled with a film of pressurized oil, an an- 1 nular groove 78 may be provided extending around the and cylinder wall.

To direct the oil downwardly from the lateral passageways and feed it into the pressure chamber'68, a pair of vertical. oraxial passageways such as illustrated at 80 and 82 in Figs. 3 and 4 are provided. The lower and of the

vertical passageways

80 and 82, at the point 'wherein they open into the pressure chamber 68, are

blocked by a check valve 84 which is illustrated in the form of an annular metal ring. This ring is of a size to slidably fit over a lower extension or hub 86 of the piston which guides the annular ring or check valve. The check valve is held in place by a coiled compression spring 88 which bottoms on the floor 90 of the pressure chamber. The compression spring 88 is of such a strength that when the oil pressure builds up within the engine to cause the oil to flow upward through the axial bore 46 in the support post, through the lateral passageway 74 and downwardly through the axial passageways 80, it will compress the spring to move the annular valve 84 away from the opening of the passageways to permit oil to flow into the pressure chamber. The spring will normally hold the check valve ring 84 in place to prevent oil from flowing out of the pressure chamber back into the oil gallery of the engine. Thus when an upward pressure is exerted on the bearing member 52 by the rocker arm, the oil pressure building up within the pressure chamber 68 will not escape but will be held in the pressure chamber by the check valve 84.

In Fig. 6 an alternative form of the annular check valve is shown with an annular valve supporting ring 89 being provided having a lower channel or groove 90 in which the spring may seat. At the top of the valve support member 89 is a metal valve washer 92 which is of thin material on the order of .010 to .020 inch in thickness.

A still another alternative form of the check valve is shown in Fig. 7 wherein a valve backing member 94 is shown having a shape similar to the member 88 in Fig. 6. The backing member is rigid in form and carries an annular groove 96 in which the spring 88 shown in Fig. 3 may seat. The valve member in Fig. 7 includes on top of the support, a resilient non-metallic washer 98 which is made of material which will seat firmly against the openings of the

passageways

80 and 82 to provide a positive check against return flow of oil.

In the valve lash adjusting mechanism of Fig. 8, a supporting post 38 similar to the one shown in Fig. 3 is provided with a bearing member 100 slidably carried thereon. The bearing member is provided with a smooth inner bore hole 102 which permits it to slide smoothly on the shank 48 of the post 38. Threaded to the top of the post is a piston 104 which is provided with internal threads 106 in order to be screwed down firmly on top of the post. The piston is slidably mounted within the smooth inner walls of the cylinder 108 of the bearing member 100 which is provided with a tubular extension 110 similar to the bearing member in Fig. 3.

As is shown in Figs. 8 and 9, the piston at its upper end is provided with a reservoir 112 which is shown in the shape of an annular channel exposed at the top of the piston and extending completely around the piston and coaxial therewith. This annular channel 112 or reservoir provides a supply of oil which will feed to the pressure chamber 114 within the bearing member when the engine is just being started or is being cranked and before the oil pressure begins to build up. To close the reservoir 112 at its top end, a cap member 116 is secured to the top of the piston and a gasket 118 is provided between the cap and piston top to prevent oil from escaping from the reservoir 112. The cap 116 has a downwardly extending flanged edge 120 which extends beyond the edge of the wall 110 of the bearing member. This prevents the bearing member from sliding too far upwardly on the piston during long rest periods of the engine if the valve spring is omitted. The spring helps maintain the piston and bearing member at extended positions.

To clamp the cap member 160 and its gasket 118 to the top of the piston, the piston contains an internal threaded hole 122 extending downwardly from the center 6 of the top end into which is threaded a stud 124 with the head of the stud clamping the cap tightly on topof the piston.

To feed oil into the reservoir 112 the axial bore hole 46 within the post is extended through the piston by hole 126 closed at its top end by the bolt 124. A lateral passageway is provided at 128 communicating between the reservoir and the vertical bore hole 126.

It is to be noted that the lateral passageway 128 extends annularly upwardly so as to enter the reservoir at a point spaced above the bottom thereof. This insures that some oil will remain in the reservoir when the engine is turned off and all of the oil will not leak back down into the oil gallery of the engine.

Three laterally extending angular passageways are provided with the passageways being shown at 128, 129 and 131 arranged apart and angling upwardly to enter the upper portion of the reservoir 112.

To feed oil down into the pressure chamber 114 of the bearing member either during operation of the engine or from the reservoir before operation of the engine, a series of vertically axially extending

passageways

130, 132, 134, 136, 138 and 140 are provided, each leading downwardly from the reservoir 112. The axial oil passageways do not extend completely down into the pressure oil chamber 114 but have eommunicating'escape holes such as shown at 142 and 144 for the

axial passageways

130 and 136. These escape holes are sufliciently large to permit an adequate flow of oil into the pressure chamber 114 but are of a cross sectional size so as to be controllable by the check valve 146 which will be described later in detail.

Thus during normal operation the oil reservoir 112 is filled with oil, as well as the passageways 130 through 140. The oil passes downwardly through-the escape holes 142 and 144 to fill the pressure chamber 114 and backflow of the oil from the pressure chamber is prevented by the check valve 146.

The annular valve member 146 is held in place over the escape holes 142 and 144 by a lightweight wave spring 148, Figs. 9 and 10. This spring. is carried on a spring support member 150 which is held in place by a coil spring 152 which bottoms on a valve member 154 resting on the floor of the pressure chamber'114. The support member is shaped with an upturned flange at its edge to support the wave spring, and openings 151 are provided in the flange to permit the oil to get past the support.

The lightweight wave spring 148 is of a strength to permit the annular valve ring 146 to be pushed away from the escape holes with .a low oil pressure. This will permit the oil to flow past the valve member 146 when low pressures are built up in the oil gallery to pass up into the lash adjusting member through the axial bore 46. These low pressures occur when the engine is first being started such as when it is being cranked over by the starter. During the starting time the valve will be held open between operations of the rocker arm for an adequate time to permit the oil to flow into the pressure chamber 114.

During high speed engine operation however, the time during which the valve ring 146 can be open is greatly shortened. Since the valve 146 acts as a check valve to prevent the 'backflow of oil, it will open only when there is no upward pressure on the rocker arm to force the bearing member 100 upwardly. This occurs only when the rocker arm is not opening the engine valve. During the cranking period of the engine the period when the rocker arm is not pushing on the valve is sulficiently long so that a small opening in the check valve 146 will provide time for adequate oil to flow into the pressure chamber 114. While the engine is running however, the engine valve will be operated with a greater frequency so that the rocker arm pushes upwardly on the bearing member 100 with a corresponding greater frequency and the check valve 146 in the valve lash member can stay open for only a very short time. This assassc means .thatthe'check' valve will have to be opened a larger-extent to 'permit sufiicient oil to flow through into the pressure chamber 114 to be able to enjoy effective operation of theivalve' lash preventing apparatus.

To permit the check-valve 146 to open a greater degree, the support member 150 for the wave spring is supported on the coilsprin'glSZ which is stronger than the wave spring 148; When the engine is being cranked the low oil pressure will open the valve against the wave spring but not against the strong coil spring and when the engine is running Weak the pressure of the oil will be sufiicient to compressthe'coil compression spring 152. Thus the valve arrangement shown provides a pressure sensitive checkvalve146which permits a small flow of oil into the pressure chamber during the long period of time available during cranking of the engine and opens the valve a large amount to permit a large flow of oil during the short time available when the engine is running.

The annular ring valve 146 being held against its seat to close the

holes

142 and 144 is-held against the holes with the soft wave spring 148 so as to permit oil to be passed down into the pressure chamber 114 from the reservoir 112 when the engine is first being started. Before the engine is cranked over during rest periods of the engine, the valve rocker arm settles against the top of the valve stem and push rod and the weight of the bearing member 100 and the force of the spring 152 will cause the bearing member to slide downwardly on the support rod 38. This will create a slight suction in the pressure chamber 114 sufficient to open the valve 146 against its weak wave spring 148 to draw oil downwardly from the reservoir 112 to maintain the pressure chamber pull so that it will be ready immediately when the engine is started. The reservoir 112 will contain sufficient oil to supply oil to the pressure chamber so that the pressure chamber will be filled and this will prevent engine noise during the first turnover of the engine and until the oil pressure builds up in the reservoir as pumped up from the oil gallery.

The compression spring 152 bottoms on the valve member 154 in the base of. the pressure chamber and which includes a U-shaped seal 156 having one lip of the seal riding against the shank 48 of the post 38 to thereby prevent leakage of oil from the pressure chamber 114 down alongside of the post between the post and bearing member. The use of this sea-l permits a greater tolerance in the fit between the post 38 and bearing member so that there can be a large-r gap between the surfaces 102 and 48. On top of the U-shaped seal 156 is a U-shaped metal ring to reinforce the seal and provide a seat for the compression spring 152.

Although the operation of the mechanism is believed clear from the foregoing detail description, a brief summary of operation will be helpful in understanding the features of the invention.

Before the engine is star-ted the pressure chamber 114 is kept filled from the reservoir 112 in the embodiment shown in Fig. 8. When the engine begins cranking oil at a relatively low pressure will fill the reservoir and the oil in the reservoir will have sufficient pressure to move the valve ring 146 away from its sea-t against the wave spring to permit oil to flow downwardly past the valve through the side openings 151 in the support member and into the pressure chamber 114. As the speed of the engine builds up the oil pressure will build up to a point sutficient to compress the coil spring 152. The pressurized oil will then flow past the fully open valve. The oil in the pressure chamber at all speeds will press the bearing member firmly down against the rocker arm.

In the embodiment of Fig. 3 no large oil reservoir is provided and therefore the pressure will quickly build up to fill the pressure chamber 68 to urge the bearing member 52 downwardly. The oil pressure in addition to feedingdown into the pressure chamber passes out through the lateral passageways to provide a pressurized oil film between the .wall' ofthe cylinder 57 and the piston 56,

:thus reducingfithexnoise between these members and decreasingwear. The oil pressure film will also prevent .lleakage from the pressure chamber 68 and the oil which does leak upwardlygoes directly through the leakage path and'does not first 'have to pass through the high pressure: oil chamber 68.

.The pressurized oiliin the oil pressure chamber 68 pushes the bearing'member 52 slidably down on the post to hold it firmly against the rocker arm. The oil is kept in the pressure chamber by the piston 56 which is secured to the post and -'valve lash of the engine valve operating linkage is prevented.

Thus it will be seen that I have provided an improved hydraulic valve'lash adjusting mechanism which meets the objects andadvantages hereinbefore set forth. The mechanism is simple. inzdesign and constructed with a minimum number. ofzparts thereby saving cost in manufacture and assembly. :r/The design of the mechanism will prevent:engine noise from the valve lash adjusting linkageuand from-the valve'linkage itself during the very early stages of starting the engine and will operate effectively throughout. the engine operation throughvarious speed ranges. The design illustrated will also reduce the wear of the mechanism providing for long operating life.

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

Iclaim as my invention:

1. A valve. lash adjuster for supporting a pivotal rocker arm onan eugine'head having a pressurized oil gallery comprising a supporting post secured to the engine head and having an axial bore in communication with the pressurized oil gallery, a bearing member pivotally supporting the rocker arm and slidably mounted on the post, said bearing member being hollow to form an oil pressure chamber defined between the post and the inner surface of the hollow bearing member, threads formed at the .upper end of the post, a piston carrying threads and being threaded to the upper end of the post to be fixed with respect to the'post. and slidably located within the hollow bearingmember to close the pressure chamber, and a conduit communicating between the pressure chamber and axial bore in the post to direct pressurized oil to the chamber and urge the bearing member against the rockerarm and take up the lash of the rocker arm.

2. A valve lash adjuster for supporting a pivotal rocker arm on an engine head having a pressurized oil gallery comprising a supporting post mounted on the engine head and provided with an axial bore in communication with the pressurized oil gallery, a bearing member pivotally connected to the rocker arm and slidably mounted on the post, said bearing member having a cylindrical here from its upper end extending coaxially with the post and a small bore on its lower end to provide a bearing surface for sliding ofsaid post, said coaxial cylindrical bore forming an oil pressure chamber confined between the post and the inner surface of the bearing, a piston secured to said post and being slidably located within the bore of the bearing member, and laterally extending passageways communicating between the piston outer wall and the axial bore of said post to supply pressurized oil to the contiguous bearing surfaces of the cylindrical bore and the piston to thereby create an oil film therebetween to reduce the noise and increase the wearing life of said piston and bearing member.

3. A valve lash adjuster for supporting a pivotal rocker arm for transferring linear motion to a push rod and the stem of a poppet valve, the lash adjuster comprisr ing a supporting-post adapted to be vertically connected to the head-of an engine, a bearing member adapted to pivotally support the rocker arm and having'a smooth bore to be slidably mounted on the post for urging the rocker arm against the pushrod and valve stem, an axial bore extending through said supporting post to be in communication with the pressurized oil gallery of the head of the engine, a cylindrical bore extending in said bearing member coaxial with said post from the upper end of the bearing member, a piston secured to the post and slidably located within the cylindrical bore of the bearing member, an oil passageway extending laterally in said piston and communicating with the axial bore of said post, and a plurality of vertical bore holes extending vertically from said oil passageway to communicate with the pressure chamber within the bearing member as defined by the cylindrical bore of the bearing member and located beneath the slidable piston, said vertical bore holes directing oil tothe pressure chamber of the bearing member to maintain the bearing member in firm engagement with the rocker arm.

4. A valve arrangement for an engine provided with a valve push rod, a spring loaded poppet valve and a rocker arm therebetween, the combination comprising an engine head having a pressurized oil gallery, an opening in said head leading to said gallery, a supporting post secured in said opening and having an axial bore hole in communication with said oil gallery, a bearing member slidably mounted on said post and containing an enlarged cylindrical bore with an axis substantially parallel to the axis of the post, a piston secured to said post being slidably mounted in the cylindrical bore within the bearing member to define a pressure chamber within the bearing member beneath the piston and within the cylindrical bore, laterally extending passageways through said piston communicating with the axial bore through said supporting post and leading to the cylindrical wall of the piston to direct oil in the sliding space between the piston and cylindrical bore of the bearing member, and passageways connecting with said lateral passageways and communicating with the pressure chamber within the bearing member to direct oil passing up through the axial bore of the post from the oil gallery to the pressure chamber to hold the bearing member in firm engagement with the rocker arm.

5. A supporting mechanism for valve gear for carrying valve operating rocker arm in non-lash contact with a valve stem and push rod, the mechanism comprising a supporting post having an axially extending bore for communication with the pressurized oil gallery of the engine head, a bearing member pivotally connected with the rocker arm and slidably mounted on said post, a piston secured to said post, a bore extending from one end of said bearing member substantially parallel with the post and slidably containing said piston, oil conducting passageways extending through said piston to communicate between the pressure chamber within the bearing member and the axial bore of the post, and check valve means in said pressure chamber and operatively connected to said passageways in the piston to prevent a return fiow of oil fiom the bearing pressure chamber through the axial bore and back to the oil gallery.

6. A valve lash adjuster for supporting a pivotal rocker arm on an engine head having a pressurized oil gallery comprising a supporting post secured to the engine head and having an axial bore in communication with a pressurized oil gallery, a bearing member having a cylindrical hole therethrough to be slidably mounted on said post and adapted to pivotally support the rocker arm, said bearing member having an enlarged cylindrical bore extending parallel With said post, a piston slidably mounted within said enlarged cylindrical bore and secured to the post to define an oil pressure chamber within said bearing member in the space closed by said piston, an oil passageway extending substantially parallel to said post and communicating between the axial bore through the post and said oil pressure chamber, an annular valve ring surrounding said post and positioned against said oil passageway, and biasing means holding the valve member in closed position over said passageway to be compressed to permit the flow of oil into said pressure chamber past the valve member with operation of the engine to hold the rocker arm in firm contact with a push rod and valve stem.

7. 'A valve arrangement for an engine provided with a valve push rod, a spring loaded poppet valve, and a rocker arm therebetween, the combination comprising an engine head having a pressurized oil gallery and an opening leading to said gallery, a supporting post connected to said opening and having an axial bore therethrough in communication with the gallery to conduct oil through the post, a bearing member slidably mounted on said post and pivotally supporting said rocker arm, a piston secured to said post, a tubular extension wall integral with said bearing member and extending to slidably house said piston and form a pressure chamber between the tubular wall and space beneath the piston, a plurality of axially extending oil holes in said piston leading from said bearing pressure chamber to communicate with the axial hole through the post to direct oil from the engine oil gallery into the pressure chamber, an annular valve member surrounding said post and located in said pressure chamber to seat against said axial oil holes, and a compression spring bottoming in said bearing member and engaging the valve member to urge it to close said axial holes, said spring being compressed to permit a flow of oil into the pressure chamber as oil pressure builds up Within the engine.

8. A valve lash adjuster for pivotally supporting a rocker arm on an engine head to operate a poppet valve in an engine having a pressurized oil' gallery, the lash adjuster comprising a bearing member for pivotally supporting the rocker arm, a supporting post secured to the engine head and having an axial opening in communication with the oil gallery of the engine head, said post slidably carrying the bearing member, a cylindrical annular Wall extending from the bearing member parallel to said post, a piston slidably mounted Within said cylindrical wall secured to the post, an oil chamber in said piston for receiving oil from the axial hole of the post, oil passageways extending through said piston equidistant from the axial center of said piston and leading from said oil chamber to an oil pressure chamber within the cylindrical wall of the bearing member as closed by the piston, an annular ring surrounding said post covering the ends of said oil passagewaysto prevent a backfiow of oil from said pressure chamber into the-oil gallery of the engine, and a spherical compression spring bearing against the bearing member and urging the annular ring against the piston to closethe oil holes.

9. A valve lash adjuster for supporting a pivotal rocker arm'on an engine head having a pressurized oil gallery comprising a supporting post secured to the engine head and having an axial bore in communication with the pressurized oil gallery, a bearing member pivotally supporting the rocker arm and slidably mounted on the post, said member being hollow'to form an oil pressure chamber defined between the post and the inner surface of the hollow bearing member, a piston secured to the upper end of the post to be fixed with respect to the post and slidably located within the hollow bearing member to close the pressure chamber, a plurality of axially extending passageways in the piston communicating with the pressure chambertand the axial opening in the post to direct oil into the pressure chamber, said passageways being equi-spaced from the axis of the piston, and a rigid annular ring positioned in said pressure chamber to surround the post, a soft resilient valve material on the upper face 'of said annular ring to be forced against said axial passageways, and spring means biasing the annular ring against the passageways and permitting the pres- :"surized oil to force. the :valve member aWay-fro m-the passageways to flow into the pressurechamber, "said valve material preventing .backfiow from the pressure zchamber.

tween the axial bore of the postand the outer cylindrical Wall of the piston, and an annular groove extending around the cylindrical wall of the piston and in communication with said lateral oil passageway to direct pressurized oil equally around the circumference of the piston between the walls of the piston and the bearing member.

11. A valve lash adjuster for supporting a pivotal rocker arm on an engine head having a pressurized oil gallery comprising a supporting post secured to the engine head and having an axially extending bore in communication with said oil gallery, a bearing member pivotally supporting the rocker arm and slidably mounted on the post, said bearing member being hollow with an axially extending cylindrical chamber to form an oil pressure chamber confined between the post and the inner surface of the hollow bearing member, a piston secured to the post and slidably located within the bearing member, an oil reservoir chamber within the piston in communication with the axial bore of the post, axial passageways leading through the piston from the oil reservoir, and escape holes smaller than the axial passageways communicating between the passageways and the pressure chamber within the bearing member to direct oil into the pressure chamber within said bearing member to hold the bearing member in firm engagement with the rocker arm.

12. A valve lash adjuster for supporting a pivotal rocker arm on an engine head having a pressurized oil gallery comprising a carrying post secured to the engine head and having an axially extending opening therethrough in communication with the oil gallery, a piston mounted on said post, a bearing member pivotally supporting the rocker arm and slidably mounted on the post, said bearing member provided with the cylindrical opening leading from one end to the pressure chamber therein and slidably housing the piston within said cylindrical bore, an enlarged closed oil reservoir within the piston in communication with the axial bore of the post, and an oil passageway leading from said reservoir directing oil out of the piston to contain a quantity of supply oil after the engine is stopped.

13. A valve lash adjuster for supporting the pivotal rocker arm of an engine head having a pressurized oil gallery comprising a supporting post secured to the engine head and having an axial bore in communication with the oil gallery, a bearing member slidably mounted on the post and pivotally supporting the rocker arm, a cylindrical bore extending from one end of the bearing member and leading to a hollow pressure chamber within the bearing member, a piston slidably secured to the post within the hollow bore in the bearing member and enclosing said pressure chamber, an oil reservoir within the piston communicating with the bore of the post, and an oil release passageway leading from the reservoir to said pressure chamber, and check valve means located to prevent a backfiow of oil from the pressure chamber into the engine gallery.

14. A valve lash adjuster for supporting a pivotal rocker arm of an engine head having a pressurized oil gallery comprising a supporting post secured to the engine head and having an axial bore in communication with the oil gallery, a bearinglrnember slidably mounted on p the post and pivotally supporting the rocker arm, a

cylindrical bore in the bearing member and forming a hollow pressure chamber therein, a piston slidably secured J to thepost within the cylindrical bore in the-bearing member and closing said pressure chamber, an annular shaped. closed reservoir in the piston, an oil passageway communicating between the reservoir and the bore of the post, oil release passageways leading from the reservoir to said pressure chamber, and check valve means located to prevent a backflow of oil from the pressure chamber into the engine oil gallery.

15. A valve lash adjuster for supporting a pivotal rocker arm on an engine head having a pressurized oil gallery comprising a supporting post secured to the engine head, a bearing member slidably mounted on the post and having a hollow interior to form an oil pressure chamber therein, said bearing member pivotally supporting the rocker arm, a piston secured to the post and slidably mounted Within the bearing member to close the pressure chamber to prevent the escape of oil therefrom, an oil storage means communicating with said pressure chamber to furnish the supply of oil to the pressure chamber when the engine is being cranked and before pressurized oil is fed up from the oil gallery, and means communicating between the gallery and the pressure chamber to feed oil to the pressure chamber during engine operation.

16. A valve lash adjuster for supporting a pivotal rocker. arm on an engine head having a pressurized oil gallery comprising a supporting post secured to the engine head and having an axial bore in communication chamber when the engine is started, said reservoir leading down from the top of the piston, an oil passageway leading from the reservoir and to the pressure chamber, a check valve preventing the return flow of oil from the pressure chamber to the oil gallery, and a reservoir closing cap clamped to the top of the piston and having a flange extending beyond the bearing member to limit the movement of the piston into the bearing member.

17. A valve lash adjuster for supporting a pivotal rocker arm on an engine head having a pressurized oil gallery comprising a bearing member for pivotally supporting the rocker arm, a post secured to the engine head and having an axial opening communicating with said oilgallery and slidably supporting said .bearing member, said bearing member having a cylindrical bore to provide a hollow interior therefor, a piston secured to the post and defining an oil pressure chamber at its base within the bearing member, an oil passageway communicating between the pressure chamber and the axial opening through the post, and a seal located in the base of the oil pressure chamber and in slidable engagement with the post to prevent leakage of the oil from the oil pressure chamber between the bearing member and post.

18. A valve lash adjuster for supporting a pivotal rocker, arm on an enginelhead having a pressurized oil gallery comprising a supporting post having an internal conduit communicating with the oil galley, a bearing member having a cylindrical bore and mounted for slidable movement on the post, said bearing member having an enlarged cylindrical bore extending from one end, a piston positioned in said enlarged cylindrical .bore and slidably mounted therein and secured to the post, the piston defining an oil pressure chamber at its base within the bearing member, a passageway leading through the piston and in communication with the conduit through the post to lead oil into the pressure chamber, a valve member for-said passageway-located in the pressurized oil chamber, a second valve member positioned in said oil chamber and slidably positioned against the post to prevent leakage of oil from between the post and bearing member, and spring means biased between said two valve members and located within the pressure chamber to hold the valve members in seated position.

19. A valve lash adjuster for supporting a pivotal rocker arm on an engine head having a pressurized oil gallery comprising a supporting post secured to the engine head and having an axial bore in communication with the pressurized oil gallery, a bearing member pivotally supporting the rocker arm and slidably mounted on the post, said member being hollow to form an oil pressure chamber defined between the post andrthe inner surface of the hollow bearing member, a piston secured to the post and slidably positioned within the bearing member to close the oil pressure chamber, an oil passageway leading from the axial bore in the post to said pressure chamber in the bearing, and a pressure responsive means blocking said passageway when not subjected to oil pressure from the oil passageway and operative to open the passageway a limited amount with oil pressures encountered when the engine is being cranked and operative to open the passageway a greater amount when the engine is at running speeds.

20. A valve lash adjuster for supporting a pivotal rocker arm on an engine head having a pressurized oil gallery comprising a supporting post secured to the engine head and having an axial bore in communication with the pressurized oil gallery, a bearing member pivotally supporting the rocker arm and slidably mounted on the post, said member being hollow to form an oil pressure chamber defined between the post and the inner surface of the hollow bearing member, a piston secured to the post and slidably positioned within the bearing member to close the oil pressure chamber, an oil passageway leading from the axial bore in the post to said pressure chamber in the bearing, a check valve in said passageway preventing a backflow of oil from the pressure chamber, a weak valve spring in engagement with the valve to hold it in closed position and permitting it to open at oil pressures encountered at cranking speeds of i the engine, a second strong valve spring spaced from the valve to be engaged when the valve is opened against the weak spring and permitting the valve to be opened a greater distance at oil pressures encountered at running speeds of the engine.

21. A valve lash adjuster for supporting a pivotal rocker arm on an engine head having a pressurized oil gallery comprising a supporting post secured to the engine head and having an axial bore in communication with the pressurized oil gallery, a bearing member pivotally supporting the rocker arm and slidably mounted on the post, said member being hollow to form an oil pressure chamber defined between the post and the inner surface of the hollow bearing member, a piston secured to the post and slidably positioned within the bearing member to close the oil pressure chamber, an oil passageway leading from the axial bore in the post to said pressure chamber in the bearing, a check valve in said passageway preventing a backfiow ofoil from the pressure chamber, a weak valve spring in engagement with the valve to hold it in closed position and permitting it to open at oil pressures encountered at cranking speeds of the engine, a support for the weak spring positioned to limit the distance the valve opens, a stronger spring engaging said support and permitting movement of the support to open the valve a greater distance at oil pressures encountered at running speeds of the engine.

22. A valve lash adjuster for supporting a pivotal rocker arm on an engine head having a pressurized oil gallery comprising a supporting post secured to the engine head and'having an axial bore in communication with the pressurized oil gallery, a bearing member pivotally supporting the rocker arm and slidably mounted on the post, said member being hollow to form an oil pressure chamber therein defined between the post and the inner surface of the hollow bearing, a piston secured to the post and slidably mounted within hte bearing member, a plurality of oil passageways extending through the piston from the axial bore in the postand opening at the base of the piston into the pressure chamber, an annular ring surrounding the post and bearing against the base of the piston over the passageway openings to form a valve member, a weak compression spring member engaging the ring to hold it in closed position against the passageways, the spring being compressible to open the valve by pressures encountered at slow cranking speeds of the engine, a hollow annular support for said spring providing a bottoming member for the spring spaced a distance from the valve to open the valve and having openings permitting the flow of oil into the pressure chamber, a second stronger spring within the pressure chamber positioned against said support to hold it in position and permitting movement of the support in a direction away from the passageways with oil pressures as are encountered at running speed of the engine to permit opening of the valve a greater distance against the stronger spring and allow a sufiicient flow of oil to supply the pressure chamber during the short periods of valve opening that are available at high running speeds.

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