US2676579A - Hydraulic adjuster for engine valves - Google Patents

Description

April 27, 1954 c GERNER 2,676,579

HYDRAULIC ADJUSTER FOR ENGINE VALVES Filed Nov. 50, 1950 2 Sheets-Sheet 1 Theadore G. Garner INVENTOR.

April 27, 1954 c, E N 2,676,579

HYDRAULIC ADJUSTER FOR ENGINE VALVES Filed Nov. 30, 1950 2 Sheets-Sheet 2 x l I 1' Q Hi g Theodore C. Gamer INVENTOR.

Aliomqs Patented Apr. 27, 1954 UNITED STATES OFFICE HYDRAULIC ADJUSTER FOR ENGINE VALVES 12 Claims. 1

This invention comprises novel and useful improvements in a hydraulic adjuster for engine valves and more specifically pertains to an automatic, hydraulically actuated slack take-up or lash eliminator for the operating mechanism of the valves of internal combustion engines for rendering their operation more quiet and efficient.

In the valve operating mechanism of internal combustion engines, and particularly in the valve operating mechanisms of engines of the overhead valve type, such as the well known Chevrolet automobile engine, there occur numerous variations in the lash, slack or clearances which are provided of necessity in the operating linkage of the valve mechanism, throughout the period or" use of the engine. Since these clearances vary in accordance with temperature changes, wear and other factors affecting the operation of engine valves, it usually happens that the mechanical linkage for operating such valves operates with excessive clearance at such times during its operation, with a resultant undesirable noise or chatter, as well as with the occurrence of excessive wear at the various contacting surfaces.

It should be especially recognized that there is an unavoidable large variation in the length of the train of valve operating mechanism between the ranges of a cold motor operation (starting) and hot motor operation (normal running) which occasions relatively great and frequent variation in the clearance needs of valve systems.

While hydraulic operating mechanisms have been heretofore proposed for automatically elirninating these clearances while permitting full closure of the valves upon the valve seats, such mechanisms have not been heretofore entirely satisfactory owing to failure of the necessary check valves which form essential elements in the hydraulic systems of the same.

It is therefore a primary object of this invention to provide a hydraulic adjuster for engine valves which shall automatically maintain the valve operating linkage at zero clearance or lash when the valve is closed and provide a predetermined lash or clearance as the linkage starts its valve operating stroke; and which will automatically compensate for variations in the lengths of the various elements of the operating mechanism which may occur during each period of operation of the engine and throughout the life of the valve mechanism while maintaining the foregoing features.

A further object of the invention is to provide a valve adjuster in conformity with the preceding object which shall have a ball check valve construction which shall be exceedingly durable and dependable in its operation, shall provide a predetermined clearance or contraction of the valve linkage at the beginning of its operation, and which shall require little or no attention during its useful life and which may be installed quickly, even by inexperienced persons.

A still further object of the invention is to provide an automatic hydraulic adjuster for engine valves as set forth in the preceding objects which may be readily incorporated in any desired portion of the operating linkage of the valve mechanism, and particularly between the push rod and rocker of the same for easy installation, inspection or servicing.

Yet another object of the invention is to provide an improved hydraulic adjuster for engine valves as set forth in the above mentioned o'cjects which may be readily formed as a single unit and which may be readily applied to existing valve mechanism with a simple change in or a replacement of only one part as Well as to new valve installations.

A still further object is to provide an adjuster in accordance with the above mentioned objects which shall require a very small quantity of oil for its functioning, may be supplied with oil from the conventional valve rocker lubricating system without modification of the latter; may be charged and bled of air in a very easy manner; and Will be operable and without damage to the plunger when dry of oil.

These, together with Various ancillary features and objects of the invention, which will later become apparent as the following description proceeds, are attained by the present invention, a preferred embodiment of which has been illus trated, by way of example, in the accompanying drawings, wherein:

Figure l is a vertical sectional view through a portion of an internal combustion engine of the overhead valve type showing the type of mechanical operating linkage with which this invention may be employed, the engine illustrated being that of the well known Chevrolet overhead valve type;

Figure 2 is a fragmentary detail view of the construction of Figure 1, showing the manner in which the upper end of the push rod has been removed to provide a space in which may be mounted the hydraulic adjuster of th present invention;

Figure 3 is a view similar to Figure 2 but showing the hydraulic adjuster unit installed between the push rod and rocker of the engine valve mechanism;

Figure 4 is an enlarged elevational view, parts being broken away, of the push rod and associated end of the valve rocker f the conventional engine with which it is proposed to employ the hydraulic adjuster of this invention;

Figure 5 is a disassembled view, parts being shown in elevation and others in section, of the various members forming the hydraulic adjuster unit of this invention;

Figure 6 is a vertical sectional view, parts being broken away and shown in elevation, illustrating the internal construction of the hydraulic adjuster unit of this invention and the manner in which the same is associated with the upper end of the push rod and the adjusting screw of arocker arm;

Figure 7 is a perspective view of the ball check valve retainer in accordance with this invention;

Figure 8 is a fragmentary perspective view of the upper portion of the hydraulic plunger forming a part of the present invention; and

Figure 9 is an elevational view of a retaining ring forming an element of the hydraulic adjuster unit.

Reference is now made more specifically to the accompanying drawings, wherein like numerals designate similar parts throughout the various views, it being observed that although the hydraulic adjuster forming the subject of this invention has been illustrated as applied to the push rod and rocker arm construction of an overhead valve mechanism of the Chevrolet engine type, that the same is equally applicable to any other valve-operating linkage which embodies relatively movable valve-actuating members.

Indicated generally at Ill is a portion of an internal combustion engine of the well known Chevrolet type, the same having the usual valves, one of which is indicated at i2 and which have their stems disposed above the cylinder head of the engine and which are adapted to be moved downwardly to their open position by the oscillation of a rocker arm [4 journaled upon the top of a cylinder head as upon a support bracket or standard l6, against the resistance of a compression coil spring 18. In this type of valve operating mechanism, a cam 26 vertically reciprocates a tappet 22 which in turn imparts vertical reciprocation to a push rod 24 having a flared upper end 26 with a spherical seat for receiving the ball-shaped lower end 28 of an adjusting screw 36 screw threadedly carried by the other end of the rocker arm 84. The usual lubricating oil passages 29 and 3| are provided in the screw and rocker.

In accordance with this invention, it is to be understood that the push rod 24 may be physically removed and replaced by a shorter push rod upon which the valve adjuster unit indicated generally by the numeral 32 is to be mounted. However, the invention is equally applicable to existing conventional engines of this type by merely cutting off or removing the upper end of the push rod 24 as by severing the same substantially upon the line indicated at 3 5 in Figure 4 to provide a shortened upper end as at 36 in Figures 2, 3, 6.

The hydraulic adjuster unit 32, forming the subject of this invention comprises a cylinder 38, having a cylindrical chamber or bore 40 therein which is open at its upper end, the cylinder having a closed lower end provided with an upwardly extending axial recess or socket 42 adapted to receive the upper end 36 of the push rod 2 after the latter has been shortened or replaced. The unit 32 may be loosely or frictionally seated upon the push rod, since the latter and the rocker I4 will retain the unit against accidental displacement. However, any desired fastening means could also be employed if desired.

Slidably received and insertable in the upper end of the chamber 40 is a plunger indicated generally by the numeral 44 and which is a dumb-bell in shape having a relatively narrow stem or tubular neck portion 65 which is preferably provided with integral upper and lower piston heads or pistons 48 and 50. There is thus provided an annular groove 52 between the piston heads which defines with the walls of the cylindrical chamber 40 an annular space constituting a reservoir for hydraulic fluid as set forth hereinafter, this reservoir being upon the exterior surface and yet between the two pistons of the plunger. This shape of plunger gives the maximum and most effective bearing surface therefor, since the same is guided at its opposite ends, prolonging the life and efliciency of operation of the plunger.

Piston 50 is preferably cup-shaped having a depending cylindrical skirt 5 3 and both pistons and 58 have preferably a tight, sliding fit in the cylindrical bore or chamber 40. This fit however is such as to permit a slow controlled fluid leakage under pressure, but one which is not capable of permitting the skirt 5&- to strike the bottom wall of the chamber 49 during the valve operating stroke of the adjuster. A fluid passage 56 extends axially throughout the entire length of the plunger and at its upper end communicates axially with the central portion of a spherical recess or seat 53 which is adapted to accommodate the above mentioned ball portion 28 of the valve rocker adjusting screw. It is preferred to form the seat 58 in the material of the piston 43, but in some instances this seat could be formed as an insert plate of the same construction as the plate 6 5 of Figure '7 to permit easy reconditioning of the unit. At its lower end, the passage 56 is provided with a valve seat 66 and a ball check valve 62 cooperates with the seat. The ball is retained in operative relation and close proximity to the seat 59 by a retainer 65 which, as shown in Figure 7, consists of a flat plate or washer 66 having a central dished portion 68 which is axially apertured as at EU to provide a port, the dished portion 68 being of a spherical shape to provide a seat in the retainer for the ball valve 62. A groove or fluid passage 12 is provided across the seat 68 and has its ends terminating in the portion 66 while its midportion is tangential of or eccentric to and intersects the port 70 as illustrated.

Instead of the axial port 10, an opening which is non-circular, as for example, a rectangular slot could be utilized; and the port or slot could also be non-axial or eccentrically positioned if desired.

A compression spring 74 is seated in a recess it formed in the bottom wall of the bore 59, and at its upper end bears against the lower surface of the flange 66 of the retainer to thereby hold the retainer against the piston head 50 and within the skirt 54 and thereby retain the ball valve in operative position with respect to the valve seats 60 and 68.

The proportions of the parts are such that a predetermined limited vertical movement is possible for the ball 82 between the two seats 68 and as. In Figure 6 the ball valve 62 is shown in its upper or closed position to indicate by the clearance between the valve 52 and the retainer es the predetermined extent of vertical movement of the valve during operation. The exact purpose of this predetermined movement will be later apparent.

However, when the ball is in its lowered or downward position and rests upon the seat $8, although the ball covers the port it, a limited flow of fluid through this port is permissible by virtue of the groove or passage l2 which is slight- I 1y oif center with respect to the port it and of the ball 52 when seated thereon. This flow of fluid can pass upwardly from the chamber below the piston be, through the port H1, and passage 52, past the valve seat at which is now open when the ball valve is in its lowered position, and into the fluid passage 55 within the plunger.

'When endwise pressure is applied upon the opposite ends of the plunger and the cylinder, the relatively inward sliding movement of the plunger with respect to the cylinder causes an increase in pressure developed in the chamber below the piston 58 to urge the valve 62 against its seat es, thereby preventing flow upwardly from the chamber into the passage 56 and thereby trapping the fluid in the chamber below the piston 5b except for the above mentioned very slow leakage between the piston 50 and the walls of the bore 46.

The annular reservoir 52 has continuous communication with the fluid passage 56 by means of a transverse bore 18 adjacent the lower end of the reservoir, and a similar bore sc disposed adjacent the upper end of the same. Consequently, by means of the bore 78 which is considerably larger than the bore 30, a constant supply of hydraulic fluid is maintained in the passage 56 and from thence is available for entry into the chamber below the piston 53 when the valve 62 is in its lowered or open position. The reservoir 52 of course receives the above mentioned slow leakage of fluid passing the piston 5t during the valve operating stroke of the adjuster.

The upper passage t constitutes an air vent whereby air collecting in the reservoir may rise from the upper end of the same and pass outwardly through the continuously open vent Bil into the passage 56 and from thence may escape at the upper end of this passage between the seat 53 and the ball member 28 resting thereon.

Adjacent its upper end, the cylindrical bore :20 is provided with an annular groove or channel 532 which is adapted to receive a retainer in the form of a split ring 84 by means of which the plunger 4% is retained in the chamber All and prevented from endwise withdrawal from the same.

The upper plunger 48 is provided with a restricted oil passage which may conveniently take the form of a spiral groove 86 having its upper and lower ends communicating with opposite sides of the upper piston 48, to thereby establish a continuous but restricted passage between the annular reservoir and a space above the upper piston 48. This passage lubricates the close sliding fit between the plunger 48 and the bore 56.

When the valve unit is properly installed be- .6 tween two valve operating members of a valve linkage such as the push rod 24 and the valve rocker i l, it will be apparent that the spring it will tend to expand the plunger and cylinder to thereby remove all slack from the valve linkage. However, the spring M is of insufficient strength to cause opening of the valve l2 against the closing force of its spring It. When the valve cam 20 lifts the push rod, and the cylinder 3s carried thereby, the fluid in the chamber below the piston Ell is trapped with the closing of the check valve 62, so that substantial subsequent relative movement of the plunger '35 with respect to the cylinder is prevented and the full stroke of the cam is effected to lift the valve or open the valve ii to the desired extent. However, the vertical movement of the ball valve 62 between its seat as and retainer 64 is of such amplitude as to permit a small, predetermined volume of fluid to be discharged from the pressure chamber below the piston 50 into the axial passage 55 and from thence into the reservoir 52 before the valve closes. This predetermined discharge causes a predetermined contraction in the valve operating linkage, of about 15 thousandths of an inch in the Chevrolet adjuster illustrated.v This at the beginning of each stroke, the desired lash or clearance for this make of valve mechanism is introduced before movement of the engine valve begins. However, when the cam 26 releases the valve mechanism and the spring it closes the valve and moves the operating mechanism to its original or lowered position the above mentioned predetermined contraction or lash of the system and the slow flxed leakage or bleed are automati'cally compensated for.

If for any reason the valve linkage should be too long as by reason of an increase in temperature of the parts of the same, so that the valve l2 will not fully seat, the force of the valve spring tending to force the plunger 44 further inwardly in the cylinder 38 will in time cause the above mentioned very slight leakage between the piston 58, its skirt 54 and the wall of the chamber Lit, which if desired may be provided with a similar spiral channel 8? corresponding to that shown. at 38 with respect to the upper piston. Should the overall length of the linkage be shorter than necessary to take up all clearance, as might occur when the temperature of the various parts of the linkage decreases, the spring 14 will expand the plunger and cylinder to take up this clearance or slack in the system and upon this upward movement the valve 62 will drop downwardly upon the retainer seat 68 thus uncovering the port (it. Fluid within the reservoir and in the passage 56 will then descend past the valve Elli into the chamber below the piston 50. This down coming fluid will pass around the sides of the valve 62 and will pass between the valve and the spherical seat 58 by virtue of the restricted passage 72, and from thence will pass through the port it. Since the passage 12 is off center with respect to the center of the port lb and valve 82, there will be a resultant twisting force applied to the ball 52 which will tend to rotate the same upon the retainer and thus constantly present fresh surfaces of the Valve to the seat t9, thereby distributing wear evenly over the valve 52 and greatly prolonging its life and the eiflciency of its sealing action with the seat 6%.

As set forth above, it is possible to form the seating surface 53 in the piston 43, in the same manner as the seating surface 68 of the valve retainer 65, or the recess 58 itself could be so constructed to provide the desired bearing surface. Thus, as seen in Figure 8, a spherical bearing and seating surface 58 is provided having an axial port 92 communicating with the upper end of the passage 56. A transverse groove or channel 94 is provided across the surface 90 intersecting the bore 92. This groove will be eccentric to the port 92, or may be diametrical thereof as preferred. The port and groove constantly vent the passage 56 to the atmosphere while the ball portion 28 of the adjusting screw 88 is seated on the surface 58.

This construction permits fluid to be readily introduced into the annular reservoir 52 and vents any air passing therefrom by the bore 8% into passage i: to the atmosphere.

The hollow construction of the plunger permits easy bleeding of air therefrom during initial filling of the system by merely inserting a rod through the passage 56 to hold the valve 62 from its seat, thereby opening the chamber below the plunger for the rapid ingress of oil and discharge of air.

From the foregoing, it is felt that the construction and operation of the device will now be readily apparent and further explanation is believed to be unnecessary. However, since numerous modifications and changes will readily occur to those skilled in the art after a consideration of the foregoing specification and accompanying drawings, it is not desired to limit the invention to the exact construction shown and described, but all suitable modifications and equivalents may be resorted to, falling within the scope of the appended claims.

Havin described the invention, what is claimed as new is:

l. A hydraulic adjuster for a valve mechanism comprising a, cylinder having a plunger slidable therein with a piston head on its lower end, a fluid reservoir, said plunger having a passage communicating with said reservoir and with the cylinder below said piston head, a valve seat in said passage, a ball check valve, a retainer holding said ball in operative position upon said seat while permitting a limited movement away from said seat, said retainer having a valve seat, a fluid port extending through said retainer, a fluid passage in said retainer seat extending entirely across the same and intersecting said port and disposed ofi center relative thereto and tangential of said port to impart a tangential thrust to said ball for rotating the latter when it rests on its retainer seat.

2. The combination of claim 1 wherein said retainer comprises a cup-shaped plate-like memher, said retainer seat being spherical.

3. The combination of claim 1 wherein said retainer comprises a cup-shaped plate-like memer, said retainer seat being spherical, said fluid passage comprising a groove in the spherical seat.

4. The combination of claim 1 wherein said retainer comprises a cup-shaped member, said retainer seat being spherical, a spring in said cylinder urging said plunger outwardly and yieldingly holding said retainer in position upon said plunger.

5. The combination of claim 1 wherein said plunger has a recess comprising with the cylinder said reservoir.

6. The combination of claim 1 wherein said plunger has a recess comprising with the cylinder said reservoir, said recess comprising an annular groove on said plunger.

7. The combination of claim 1 wherein said plunger has a recess comprising with the cylinder said reservoir, said recess comprising an annular groove on said plunger, said annular groove having vertically spaced bores communicating with the plunger passage.

8. The combination of claim 1 including a piston on the upper end of said plunger, means on said last piston effecting a slow leakage of fluid past said plunger.

9. A hydraulic adjuster for a valve mechanism comprising a cylinder having a plunger slidable therein with a piston head on its lower end, a fluid reservoir, said plunger having a passage communicating with said reservoir and with the cylinder below said piston head, a valve seat in said passage, a ball check valve, a retainer holding said ball in operative position upon said seat while permitting a limited movement away from said seat, said retainer having a valve seat, a fluid port extending through said retainer, 2. fluid passage in said retainer seat intersecting said port and disposed off center relative thereto to impart a tangential thrust to said ball for rotating the latter when it rests on its retainer seat and a piston on the upper end of said plunger, means on said last piston permitting a slow leakage of fluid past said plunger, said last means consisting of a spiral channel disposed upon the circumference of said last piston.

10. A hydraulic valve adjuster comprising a cylinder having a plunger slidable therein with a piston head on it lower end, a fluid reservoir, said plunger having a passage communicating with said reservoir and with the cylinder below said piston head, a valve seat in said passage, a ball check valve, a retainer holding said ball in operative position upon said seat while permitting a limited movement away from said seat, said retainer having a valve seat, a fluid port extending through said retainer, a, fluid passage in said retainer seat and extending entirely thereacross and intersecting said port tangentially thereof and disposed off center relative thereto to impart a tangential thrust to said ball for rotating the latter when it rests on its retainer seat, means mounting said cylinder upon the upper end of a valve push rod, means for 0peratively connecting the plunger to a valve actuating rocker.

11. An adapter unit for valve operating mechanism of the overhead valve type having a push rod connected to a valve rocker, comprising a hydraulic adjuster for a valve mechanism comprising a cylinder having a plunger slidable therein with a piston head on its lower end, a fluid reservoir, said plunger having a passage communicating with said reservoir and with the cylinder below said piston head, a valve seat in said passage, a ball check valve, a retainer holding said ball in operative position upon said seat While permitting a limited movement away from said seat, said retainer having a valve seat, a resilient support for said retainer, a fluid port extending through said retainer, a fluid passage in said retainer seat extending entirely thereacross and tangentially intersecting said port and disposed off center relative thereto to im part a tangential thrust to said ball for rotating the latter when it rests on its retainer seat, means for securing said cylinder to the upper end of a push rod, with the plunger engaging the rocker arm.

12. A hydraulic adjuster for a valve mechanism comprising a cylinder having a plunger slidable therein with a piston head on its lower end, a fluid reservoir, said plunger having a passage communicating with said reservoir and with the cylinder below said piston head, a valve seat in said passage, a ball check valve, a retainer holding said ball in operative position upon said seat while permitting a limited movement away from said seat, a resilient support for said retainer, said retainer comprising a flat dishshaped member having a valve seat, a fluid port extending through said retainer, a fluid passage in said retainer seat extending entirely across said retainer and tangentially intersecting said port and disposed off center relative thereto to impart a tangential thrust to said ball for rotating the latter when it rests on its retainer seat,

a pair of valve operating members, means for securing said cylinder and plunger to adjacent ends of said operating members.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,469,106 Phillips Sept. 25, 1923 1,792,836 Handwerker Feb. 17, 1931 2,071,051 Van Ranst Feb. 16, 1937 2,074,155 Truesdell Mar. 16, 1937 2,116,749 Daisley May 10, 1938 2,542,036 Knaggs Feb. 20, 1951

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