US2053743A - Valve operating mechanism - Google Patents

Description

R. c. RUSSELL 2,053,743 VALVE OPERATING MECHANISM Filed Ju1$r"10, 1955 s Sheets-Sheet w1 I Sept. 8, 1936.

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VALVE OPERATING MECHANISM Filed July 10, 1953 3 Sheets-Sheet 2 FIG. 6

INVENTOR ROBERT. C. .RUJSEZL +W ATTORNEYS Sept- 8, c RUSSELL VALVE OPERATING MECHANISM Filed July 10, 1953 3 Sheets-Sheet 3 INVENTOR ROBE/P7 6. R USSEZL QM W ATTORNEYS Patented Sept. 8, 1936 UNITED STATES PATENT OFFICE 27 Claims.

This invention relates to valve operating mechanism and more particularly to hydraulic self adjusting or compensating rocker arms used principally in connection with internal combustion motors to automatically maintain a noclearance operating engagement between all parts of said valve mechanism.

A main purpose of. the invention is to produce a new and useful hydraulic rocker arm which is adapted for use with conventional or standard cam operated valve means employed in internal combustion engines and to compensate for variation in length of the operating parts due to wear and temperature changes. To this end, the invention provides a hydraulic rocker arm, rugged in construction, having few parts, economical to manufacture, which is positive in operation in carrying the load or pressure of the springloaded engine valve reacting against the enginedriven cam, which silences the valves and their operating mechanism, and increases engine efliciency.

A characteristic object of the invention is to produce a hydraulic rocker arm having its automatic self adjusting parts or compensating means carried within one of the lever arms of the rocker and receiving its working supply of oil from the rock shaft on which the arm oscillates under the action of the engine driven cam to open the spring closed engine valve and-carry its load and permit said valve tosoftly close on its seat thru an incompressible oil body confined in an automatic self adjusting hydraulic compression or pressure chamber, whereby all parts of the mechanism are held to zero-clearance or no-clearance engagement.

A further object is to produce an automatic self adjusting rockerarm carried on a fixed axis as distinguished from known types which oscillate on an eccentric bearing wherein said eccentric automatically moves the rocker arm up and down in relation to the valve stem and push rod to maintain zero-clearance between the operating parts. One example of my invention, as illustrated herein, carries out its automatic function without recourse to a self adjusting rocker arm bearing or eccentric, by providing a compensating unit in direct engagement with either the valve stem or push rod. Consequently, I make use of the conventional bearing now in general use to mount my automatic rocker in operating position and thus avoid undue changes from standard engine design when I install my rocker arms on internal combustion engines.

Another object is to produce ahydraulic rocker arm having compensating instrumentalities including means acting to positively expel the air, or the maximum thereof, from its hydraulic compression chamber, prior to the oil filling operation, to thus avoid entrapped or occluded gas and air bubbles, and by which is secured a positive and solid oil or liquid body thru which to transmit the force, or a part thereof, from the rotating cam to the reciprocating valve to open or actuate the latter against the compression of its closing spring.

Pursuant to the air-expelling function above stated, it is a further object of this invention .to produce a hydraulic rocker armhaving maximum displacement means by which the volume of. the oil compressionor hydraulic chamber reduces to zero or of minimum space, is, minute or. nil in volumetric capacity, (or the chamber entirely closes or disappears for complete displacement) upon the first turn of the engine cam, preliminaryto sucking a charge of oil into the maximum displacement oil chamber, and in this way the air is expelled from the hydraulic compression chamber and thus conditions said chamber to receive and retain a solid body of oil free of air. Thus is minimized the likelihood of the oil becoming air bound or locked, aerated and emulsified, and hence I prevent the hydraulic oil body from losing its incompressible characteristics.

The foregoing object, i. e., the attainment of maximum chamber displacement, can of course be carried out with either a large or small volume hydraulic chamber. I have, however, illustrated my invention with a reduced-size or minimum volume compression or pressure chamber of the maximum displacement type, the object being to operate the self adjusting unit in the rocker arm on a comparatively small oil body and thus make use of a minimum of aerated oil in any event. Furthermore, an object related to these featuresbeing described is to provide, if desired, an air escape or bleed, located high in the compression chamber, whereby such little air as may find its way into the minimum-size maximum-displacement chamber is rapidly expelled during operation and before the oil becomes air mixed and softened.

A still further object is to produce a rocker arm having a combination of hydraulic and mechanical means to reduce the pressure on the oil,5 within the self adjusting hydraulic compression chamber, the result of which is to minimize the tendency of the oil to escape therefrom as well as lowering the tendency to aerate and emulsify the Oil. In this connection the same feature also ciples thereof.

serves to produce a very sensitive and instant oil filling operation since an extremely small contraction of the valve stem, push rod, or other part, reacts to initiate a much greater movement of the compensating means, with an equally great change or increase in the volume of the hydraulic compression chamber, and consequently a quick oil filling operation takes place. In all, this or these features combine to produce an automatic self adjustingmechanism which is highly sensitive to slight changes in length of parts due to temperature variations or wear in the bearings.

An additional object is to produce mechanical leverage means for relieving or minimizing the pressure on the oil in the hydraulic chamber, and said leverage means carries and transmits the major portion of the load of the spring-loaded valve, the operation of such leverage means generating a certain amount of friction; and thus the mechanical leverage and the friction serve to relieve the hydraulic compression chamber of the greater portion of the valve and cam load. In this way, my compensating rocker arm gains all the advantages of a hydraulic self adjusting means but retains the positiveness of mechanical means for transmitting the major operating forces.

Another object is to produce a rocker arm the self adjusting means of which lends itself well to manufacturing conditions, whereby it may be conveniently produced with either a low or high compression hydraulic chamber, depending on which type or form appears most desirab e from the standpoint of performance for different uses and varying types of engines.

Other objects and purposes of the invention are brought out in the following description or will be apparent to those skilled in the art.

The accompanying drawings illustrate examples of the invention by which to disclose the prin- However, it is understood that changes in form and operation may be resorted to without departing from the spirit of this invention.

Fi ure 1 shows a side elevation diagram of a com lete valve operating mechanism including a hydraulic rocker arm in partial longitudinal section. In this view, the hydraulic compensatng chamber is a low pressure form and shown full of oil with the self adjusting means in fully extended position, all parts in no-clearance engagement, and thus compensated for variation in length of all parts.

Figure 2 shows a rear view of the rocker arm, as seen from the left in Figure 1, and the upper end of a push rod in working engagement therewith.

Fi ure 3 shows a cross section on the line 3-3 of Fi ure 1, except there is shown how an oil feed groove may be formed in a rock shaft, instead of in the rocker arm hub in Figure 1.

Figure 4 is a plan view of the rocker arm mounted on a broken away rock shaft portion.

Figure 5 shows an exploded or disassembled view of the rocker arm with its self adjusting parts drawn outwardly from the rocker arm cylinder and hydraulic compression chamber and arranged in the order of which said parts are adapted to be assembled in the cylinder.

Figure 6 is a side longitudinal sectional view of the rocker arm self adjusting parts in fully closed or compressed position with its hydraulic compression or oil compensating chamber shown dry and without oil therein, the ball check valve being unseated preliminary to taking in a charge of oil. This view shows the compression chamber collapsed to its limit thus expelling all air by leaving no void spaces or air pockets therein, a function of the maximum-displacement chamber means, just prior to sucking in a full charge of oil.

Figure 7 is a cluster view of a stationary washer or plug adapted to be disposed within the hydraulic compression chamber to act as a spring seat and to hold the spring away from the ball as well as retaining the latter within a somewhat limited space though free for movement, and having oil passages therethrough.

Figure 8 is a side view of a similar rocker arm, but showing a modification in the compensating parts by which all the load, other than that absorbed by friction of the leverage wedging means, is transmitted thru a high compression hydraulic chamber and then to the valve by 45- degree wedge angle means. Consequently this is a high compression form of the hydraulic rocker arm, while the other views show the low compression type.

Figure 9 illustrates another modification having features especially for retaining the compensating parts in place after assembly of the complete rocker arm but before it is installed on an engine or the push rod is set in place.

Referring to the drawings, there is shown a conventional engine cylinder head 2 having an inlet or exhaust port seat 3, as the case may be. A spring-loaded poppet valve 4 with its stem 5 is normally seated by the usual valve closing spring 6. In standard practice, a rocker arm 1 has its hub 8 oscillating on a tubular rock shaft 9 supported above the engine cylinder 2 in any approved manner, as by a bracket l8. In this invention, the self adjusting means is compactly arranged within the rear end l2 of the rocker arm which is tubular or bored to form a cylinder I3. Thus the rocker includes a central bearing hub 8 carrying a solid arm 1 and a tubular arm l2. A push rod I4 is interposed between the rocker arm and the engine cam l5 to actuate said rocker arm 1 which constantly engages the valve 5. A valve tappet I6 reciprocates in a bearing guide I1 usually carried in the crank case of an internal combustion engine. The tappet sleeve I 6 acts as a cam follower to transmit the cam action and load to the push rod I4 and thence to the rocker arm and the spring-loaded engine valve 4, 6. A conventional rocker arm 1 and the like ordinarily has a clearance space between it and the valve 5 or between the push rod M and arm end l2 to insure the seating of the valve under all operating conditions and consequently an operating backlash occurs.

The hydro-mechanical self adjusting rocker arm comprising this invention automatically and continuously adjusts out the above mentioned conventional operating clearances and back lash, occupies very little space, silences the valve operation, and improves the performance of an engine. My new compensating means is arranged within a cylinder l3 bored into one of the lever arms of the rocker, say the rear arm I 2, and positively maintains the front arm I in zero or no-clearance engagement with the valve stem 5 and also holds the push rod ends in close working no-clearance engagement with the rocker arm and cam means under any and all operating conditions, regardless of elongation or contraction of the push rod I 4, the valve stem 5 and other parts, or due to the wear' of the mechanism or the :bearings thereof. I I

In the accompanying'illustrated embodiment of the invention, the compensating rocker armi'bore or cylinder l3 opens at its innermost or bottom end thru an: oil inlet port or ball seat'20' into an oil channel2| connecting with a'circu'rnferential oil .supply groove 22 which is eitherformed in the rocker arm hub B'or made in the rock shaft 21 as indicated at 28 in Figure 3, as later described. The hub groove 22 connects with an oil hole 23 formed thru the wall of a hollow rock shaft 9 and thence leads into the central oil passage 24 of said shaft. It is the usual practice to provide a tubular rock shaft Sfor-the'standard rocker arms of an overheadvalve engine in'o'rder to convey lubricating oil to the bearings of all rocker arms extendingalong the cylinder head 2 from oneend of the engine to the other. My invention makes use of this oil supply and draws thereon to fill a hydraulic low compression chamber in the cylinder l3, as will be explained.

in Figure 3, however, the circumferential-oil passage, heretofore designated as 22'; is made in the rock shaft: instead of in the rocker arm hub.

Therefore, this modification shows a plain bear- .ing rocker arm hub 26 adapted to oscillate-upon a circumferentially grooved rock shaft 21.. Thus it is noted that this rock shaft 2! is. made with .an external oil feed groove 28 adapted tocommunicate with the same longitudinaloil passage 2|, as heretofore described in Figure 1. This form of construction is preferred in some instances so as to produce a plain bearing rocker arm'hub 26 'journalled to oscillate upon the grooved rock shaft 21 so that the two oil'feed'passages 2| and 28 connect with each other and thereby are placed in communication with the'transverse oil passage or hole 23 and lengthwise passage 24 in the rock shaft, as already described.

A ball check valve 33 normally rests on its port seat 2|! thus shutting off a reverse flow of oil from the cylinder i3 back thru the passage 2i. once. the oil is entrapped behind said ball 30 within'a compensating low compression hydraulic chamber3| formed at the bottom of said cylinder l3 between said inlet valve 20, 33 and a compensatingpiston means to be described. There is pro'videda, perforated or grooved oil passage spring seat, in the form of a stationary plug washer or disc 32. 7 It is disposed in the bottom ofthe cylinder l3 within the'self adjusting compression or'pressure chamber 3| and over the ball check 30 as'a cap or ball retainer to hold the latter in place for free but limited movement off and on. its seat 2!). This ball retainer and spring seat is enlarged in Figure 7 and 'its'reference character 32 points to the flange thereof against which a spring rests, as later described.

The above named washer 32 may'begrooved at 33 on its flat face adjacent the ball check 30 to provide limited movement of said ball check in respect to its oil inlet port or seat 23 of the latter. Particularly, the grooves 33 form oil passages to afford a ready flow of oil thru the washer 32 since the latter is disposed within the hydraulic oil chamber 3|. Free movement of the ball 39 is shown in Figures 6 and 9 where the unrestrained ball check 30 is unseated and has dropped to rest against its retainer washer 32 due to the fact that no oil is present in the compression chamber 3| and consequently no hydraulic pressure is acting in said chamber to seat the ball check 30 against the oil inlet port 23 opening directly into the-feed passage 2|.

The spring-seat. 32 may to advantage be :providedwith a central boss 34, see enlarged views in Figure'l, directed outwardly toward the 'open endof the cylinder "bore l3 in the rocker arm.

Next there is mounted a return compensating .coil

the spring 35free'to -compress or expand in the 55 compression chamber portion 3| of therocker arm cylinder 13; A short compensating plunger or closc -fit oil piston 36 'also'ha's a boss 31 similar to the stationary springseat boss 34. This piston 35, 31 is disposed against-the outer free end of 'the'spring 35 and is adapted. to move in'the cylinder |3 outwardly-inexecuting the sel-i adjusting function of the rocker arm. The piston 35als o sets off or defines the front end of the low compressiori hydraulic compensating chamber 3| of small volumetric capacity and maximum dispiacem'ent'form. There is next provided a long or outer p unger. inthe form of a compensating wedge 33, which has its inner end resting against the oil; seal piston plunger 38 has a portion thereof cutaway from its -"rear end' toward the piston 35, thereby providing sin-underneath angular compensating face 39 The longer compensating more or less, to theaxis' of the cylinder I35 This plunger '38 need not be made to such'a'closeoil fit as the piston because the latter seals the oil sufficientlywell in the compression chamber 3|. While I prefer to make the piston 36 and plunger 38 in two separate pieces for manufa'cturing advantages, they may of course be made in one part if desired. r

- The wedge plunger 38, 39 serves the useful purpose of reducing the operating load and thrust'on the entrapped-oil in the hydraulic chamber'3l, thereby prov'iding'a low compression chamber 3|. Therefore,'the incompressible oil body in the hydraulic chamber 3| is required to'carry a part only of the thrust and load generated by the cam"|5 and valve spring 6, as will more fully appear,

when a description is 'give'n of the means cooperatingwith this wedge member 38 and its inclined plane or wedging face-39. The angle at 39 may range somewhere between 15 and 35 degrees,'the lower figure'approachi'ng the sticking'or nonsliding point, while the higher figure begins to transmit considerable pressure to'the oil in the hydraulic chamber; and a satisfactory 'com'pro mise angle is about 20 degrees.

At this stage of the-description, point out some of the features characterizing the compensating hydraulic oil chamber 3|, whether or low or high compression, and the closely related compensating parts, such'as the coacting and special operating function of the bosses34- and 31, aswell as the compensator spring 35, contained therein and their improved operating mode in relation to the oil inlet valve 3!! leading into saidchamber 3|. 'iThis construction and mode of operation'hasto do with the maximum displace- .1 and 6. The first view shows the mechanism it is desired to under operating conditions, i. e., filled with oil, while the second view shows the position of parts before the compression chamber 3| is charged with oil. It is important to note that the spring 35 and its two central guide bosses 34 and 31 completely fill the compression chamber 3|, thereby attaining maximum displacement which expels all air, when the compensating mechanism is collapsed to its limit as shown in Figure 6 The foregoing clearly brings out the fact that all of the air is expelled from the compression chamber 3| when its piston and plunger means 36, 38 moves toward the bottom of the cylinder 3 for the purpose of making ready to draw a charge of oil from the supply passage 2| past the ball check 30 over the grooved face 33 of the washer 32 and hence into the compression chamber 3|. All or most of the oil space comprising the compression chamber 3| having disappeared when the self adjusting parts are at their limit of travel in Figure 6, it follows that the maximum of air is displaced from or driven out of the chamber.

In attaining the foregoing function, the two spring bosses 34 and 31 come together, one abutting the other, and the surrounding spring 35 is so designed and constructed with the correct number of coils and proper diameter as to completely fill all space or close up said space within the oil compression chamber 3|. In other words, I have specifically designed the two hydraulic chamber bosses 34 and 37 with precisely defined dimensions. Their diameter is equal to the inside diameter of the coil spring 35, while the total length of the two bosses is exactly equal to the length of the collapsed coil spring when compressed upon itself to the limit. Thus the spring is nested solid and leaves no air space around the bosses when they come together, as in Figure 6.

The characteristic feature set out in the foregoing paragraph is especially well shown in Figures and 6 where I have illustrated another form of expanding or return compensating spring 4|, the coils of which are square or rectangular in cross section. My construction employs either type of spring for the compensating unit within the bore I3, either the cylindrical cross-sectional spring 35 or the rectangular cross-sectional spring 4| either of which collapses until the several coils touch each other to completely fill solid the compression chamber 3| when the compensating piston 36 moves toward the bottom of the cylinder l3. There remains no void, air space or spaces, in the chamber 3l because the spring coils, especially spring 4|, contact or close on each other at the same time the boss means 34 and 31 close up. Hence there is accomplished maximum compression-chamber displacement and no air remains in the chamber 3| to interfere with and retard the intake of oil and mix with the oil to render it compressible when a charge of oil is drawn into the chamber. For this reason there is eliminated all trouble as to oil emulsification or softening and thus I have at all times a solid non-compressible liquid body in the compression chamber 3|.

Another feature of my hydraulic rocker arm, which revealed itself after long experimentation, is to make the small piston'36 a close oil fit in the cylinder l3, and then provide a minute airbleed passage 29 scored a few thousandths of an inch in its cylindrical surface. Observe this construction in Figures 1 and 5 where the dotted line 29 indicates somewhat an exaggerated depth of this air bleed. It is of course very small when used. It is to be understood that I also may form the minute air escapement longitudinal passage 29 in the top surface of the plunger 38, although this is not essential inasmuch as the plunger 38 need not be as perfect an oil-seal fit as the hydraulic piston 36 and consequently the expelled air will escape around the plunger 38. The oil piston 36 is always placed in the cylinder with this air escapement 29 in uppermost position and it is found that it remains and operates in that position. Should any air remain in the compression chamber 3| by surviving the means I have produced to avoid air looks, it will gradually be expelled thru the bleed passage 29 located high in the hydraulic chamber.

A further characteristic built into my hydraulic rocker arm is its low or small capacity hydraulic or compression chamber formed by arranging the piston 36 to have a short stroke. Long experimentation revealed that this plan of construction aids in overcoming the difliculties experienced with air entrapped inside the oil chamber so that should any air remain therein despite the provisions discovered and provided thereagainst in my invention, it is found to do little harm and not interfere with good performance. Should the maximum displacement characteristics of my invention and the air bleed 29 fail to prevent a retention of a slight trace of occluded air or a gas bubble in the compression chamber 3|, it follows that said chamber is so small that the little oil in the chamber cannot occlude and retain enough air to render the oil compressible to a perceptible degree. Note, for example, the extremely small volumetric capacity of the compression chamber 3| in Figure l and chamber 55 in Figure 8. Eventually it was discovered that a small oil chamber was actually successful since it offered a minimum or low volume oil body to occlude and retain gaseous or air bubbles.

I have, therefore, combined a number of factors in my construction to make it successful, noteworthy features of which are the small volume oil chamber, maximum displacement thereof, and the other features being explained herein. These two features are realized by constructing the self adjusting unit with a short stroke piston having a movement only slightly in excess of the maximum travel required to accommodate the greatest variation met with in conventional engine valve operating mechanism. Thus by dispensing with long stroke pistons in my rocker arms, I attain certain definite results in operation not heretofore possible to accomplish outside of purely laboratory experimental sets.

The compensating cylinder I3 is provided with a plunger opening 43 in its lower side and at the rear end thereof. A self adjusting wedge plunger 44 is movably confined in the hole 43 and coacts with the first named compensating wedge 38. The upper end of the wedge plunger 44 is made with a bevel or angular face 45 on the same angle, about 20 degrees, to ride against the face 39 of the wedge plunger 38. The lower end of this wedge plunger 44 is made with a ball socket 46. The wedge plunger 44 is positively retained in its operating position, coaxially with the push rod 4 and at right angles to the axis of the rocker arm, by reason of the guide hole 43 in the cylinder 3 and said plunger 44 is adapted to compensate or move in and out of said cylinder relatively to its companion wedge plunger 38. The push rod I4 is ordinarily provided with a ball joint or head 41 which rests within the socket 46 of the wedge plunger 44.

As illustrated in Figure 6. oil grooves 40 may be made in the coacting' wedge faces-39 and 45 of the plungers and an oil hole 42 in the plunger 44 if desired. In this way, a film of oil works up the face 39 and down into theball and socket joint 46, 41 to lubricate these several parts. sufficient oil feeds or leaks past the piston 36 to lubricate the leverage wedge means 39, 45 and push rod joint 46, 41.

In operation, the reciprocating push rod [4 rapidly opens the engine valve 4 as the cam I4 rotates, as will be understood. The major thrust of the push rod I4, required to compress the engine valve spring 6, is transmitted thru the co.- acting wedge means 44 and 38 and) directly thru the rear end I2 of the rocker arm to the valve stem 5, while the remainder and lesser portion of the cam valve spring load and thrust is transmitted directly thru the solid oil body entrapped within the low compression chamber 3|. .The comparatively flat self adjusting angle 39, 45 in relation to the axis of the cylinder I3, causes the thrust of the push rod I4 to be borne largely by the plunger 39 and transmitted directly to the rocker arm end I2, while the entrapped oil body in the low compression chamber 3| is merely called upon to prevent a retrograde movement or right-hand slipping action of the wedge plunger 38 and its oil piston 36 toward the bottom end of the compression chamber 3|, i.v e., toward the valve 39. erted by the .cam and push rod l4 against the valve spring 5 is absorbed mechanically and by the friction of the coacting wedge faces 45 and 39 as well as by the leverage force reduction means inherent in the inclined plane wedge-faces 39 and 45 which effect a rightv angle transmission of the operating force.

Having, as above explained, greatly reduced the working pressure on the oil in the hydraulic. compensating low pressure chamber 3|, by em-.

ploying a comparatively flat angle 39, 45 though steep enough to avoid sticking, it follows that there is less tendency for the .oil to escape from said chamber, with the result that there is very little or in fact. no slippage of the wedge plunger 38 towards the ball check during the short interval of time in which the cam I5 is in up position to open the valve 4 against the great force of the engine valve spring 6. Furthermore the low pressure applied to the oil in the hydraulic chamber 3| very greatly minimizes the tendency to emulsify .the oil therein by a beating and churning action. This latter difficulty has heretofore caused considerable trouble in that the terrific pounding of the oil under high compression tends to not only beat and force the oil by impact out of the compression chamber but also tends to release the occluded gas or air and emulsify the oil, thus destroying its non-compressible characteristics, the result of which has been frequent failure of the known types of hydraulic compensators, rocker arms and the like, .to perform their intended functions.

I will now briefly describe the compensating action by which the rocker arm automatically self adjusts itself to variations in temperature and consequently accommodates itself to all variations in length of valve operating parts to maintain no-clearance engagement between all parts. under all engine conditions.

Take'for example a cold engine when it first starts, the pushrod l4, valve 5 and other parts may loe in contracted condition and hence are a few thousandths of an inch shorter than when they become hot. In starting cold, the return Hence most of the load or force excompensating spring 355 had previously urged the compensating piston 36 outwardly with the result that the ball check 30 opened under suction to allow oil to flow from the passage 2| into the low compression chamber 3|. After this filling action was complete, the ball 3|! instantly closed and trapped-the charge of oil'in the chamber 3|. As the engine begins to warm up and gets hot, the push rod I4, valve 5, and other parts expand or elongate. There is now a tendency for the engine valve 4 to not quite close on its seat 3, but this never occurs because the condition automatically rectifies itself thru the compensation which is enforced by the positive action of said valve spring 8 to seat its valve 4 against the compensating means as gradual elongation of parts takes place, and enough oil leaks from the compression chamber 3| past the piston 36 to allow said piston to creep toward the spring seat 32. This com-. pensation of the rocker arm, for elongation of the valve mechanism, follows b y reason of the fact that the load pressure exerted by the cam I5 and valvespring 6, assisted somewhat by the high speed'operation of the parts, causes the wedge 44 to creep upwardly on the wedge face 39 and thereby very gradually urging or moving the plunger 33 to the right, thus admitting the plunger 44 to retract inwardly of the rocker arm cylinder 13 in precisely the same degree or amount as elongation occurs in the push rod l4 and valve stem 5. In other words the plunger 44 moves inwardly a few thousandths of an inch, the oil in the hydraulic chamber 3| being forced to leak out, to accommodate elongation of the valve operating mechanism, the angle 39, 45 lending itself to promote this movement, inasmuch as the force produced by the cam I5 and engine valve 6 overcomes the resistance of the small compression spring 35 in the selfadjusting unit.

Consider now the reverse mode of compensation, i. e., self adjustment for gradual contraction of the mechanism or parts 5 and M when the operating temperature of the engine drops or when the parts wear. In this event, the return spring 35 urges outwardly on the plunger 38 and the angular face 39 of the latter correspondingly urges the lower wedge plunger 44 downwardly to continually maintain the no-clearance engagementor zero contact relationship at the ball and socket joint 46, 41 and between all other engaging parts. As the plunger 38 moves outwardly or to the left, the free non-spring pressed ball check 39 ver-y sensitively unseats and admits just enough oil from passage 2| into the low compression chamber 3| to expand and accommodate the increased volume therein. The ball check 30 sensitively closes on its seat 20 at the instant suction in the chamber has discontinued due to the fact that all play has been removed from the engaging parts and no further outward movement of the plunger 38 takes place.

It is noteworthy that the wedge plunger 38 moves, for example, out several thousandths-of an inchmore and faster than the variation in length of the push rod M or valve stem 5, for example, contraction of the latter. This operating ratio or relation transpires by reason of the low or flat angle 39, 45 between the'compensating' wedge plungers 38 and 44. Thus if the long push rod I4 shortens only one-thousandth of an inch, the plunger 38 moves out several thousandths of an inch and thus moves perceptibly .and sufficiently to quickly unseat the ball check 30 and draw a charge of oil into the low compression chamber 3|. This oil is instantly trappedandbecomes a solid incompressible body whereupon the next turn of the cam lobe l5 upwardly serves to positively compress the engine valve spring 6 and open its valve because the oil body locked within the low compression chamber positively holds the wedge 38 against displacement.

This rocker arm has a satisfactorily long compensating range and there is no need for a manual adjustment screw in setting up and tuning the valve mechanism on an engine. The self adjusting function is automatic and continuous and takes place in either direction under all working conditions. Should the push rod l4 and other parts grow in length, the wedging force of the plunger 44 against the plunger 38 urges the latter inwardly and enough oil will leak past the plunger means 36 and 38 to allow a contraction of the oil volume and body within the low compression chamber 31. Only slight oil leakage is necessary to accommodate the gradual elongation of the push rod l4 or valve stem 5. On the other hand, compensation in the other direction takes place by reason of the expansive force of the self adjusting spring 35 to keep the plunger 38 urged outwardly and maintain all parts in zero or noclearance operating engagement.

The type, form and horizontal position of the cylinder l3 and its coacting parts is found to give satisfactory performance, but I may vary the arrangement thereof in numerous ways without departing from the principle of the invention.

The high compression rocker arm in Figure 8 In Figure 8, I illustrate the simplicity with which this invention may be adopted to high compression form or type rocker arms. This is accomplished by varying the angle of the contacting wedge faces or inclined planes 39 and 45 of the self adjusting plungers 38 and 44 above described.

In this view of the invention, Figure 8, there is shown a rocker arm having a high compression hydraulic oil chamber, by reason of a change in the compensating angle on the self adjusting wedges, say about 45 degrees, instead of the low compression hydraulic chamber as first described in Figures 1 thru 6. A cylinder 5| retains the compensating mechanism, comprising two wedges 52 and 53 which have their coacting wedge faces 54 formed on the 45-degree angle or more, which provides for a full load carrying capacity against and thru the oil in its high compression self adjusting hydraulic chamber 55. Hence this hydraulic rocker arm 50 and its chamber 55 is of high compression form.

It will be noted that the form of the invention heretofore described in Figures 1 thru 6, illustrates its coacting wedge faces 39 and 45 as formed on an angle between 15 and 25 degrees, say approximately 20 degrees (which affords satisfactory operation) from the axis of the cylinder l3 and in that form of the invention the pressure or leverage exerted on the oil in the compression chamber 3| is low or greatly reduced by reason of the inclined plane of the two coacting wedges 38 and 44 which operatively engage thru their angular faces 39 and 45. In other words, the stroke of the plunger 38 is greater than the compensating movement of the plunger 44. On the other hand, in this form of the invention in Figure 8, the angle or inclined plane at 54 is about 45 degrees in relation to the axis of compensating cylinder 5| or 55 so that each plunger 52 and 53 has a movement equal to the variation in length of the push rod 56 and other parts in order to produce the desired compensating efiect. Thus the leverage or pressure on the oil in this high compression chamber 55 is approximately equal to the load or pressure on the push rod 56 required to open the engine valve. Strictly speaking, if the angle at 54 is 45 degrees, the pressure or operating load applied on the solid oil body in the chamber 55 is equal to the force exerted by the cam I5 to compress the engine-valve spring 6 and operate the train of mechanism, minus the operating friction present in the self adjusting unit including principally the sliding coacting wedges.

It is now apparent how approximately all the load of the engine valve spring 6 is carried directly by the oil body in the high compression chamber 55. Indeed, all the load, or more, can be exerted directly or proportionately one-to-one on the oil body by increasing the angle at 54 beyond 45 degrees if desired. However, it is found that amplified oil pressures present other problems and hence a low pressure hydraulic rocker arm is usually preferred. This explanation, therefore, serves to illustrate the invention and discloses how the rocker arm may be made to obtain the best operating results by changing the compensating angle to increase or decrease the pressure on the oil chamber, if desired. The construction of this valve compensating rocker arm is otherwise the same as heretofore described.

Means to hold the parts in assembled relation In Figure 9, there is shown the same rocker arm construction, having the same mode of operation, as heretofore described, comprising my compensating unit mechanism compactly arranged within a cylinder 58 of a lever arm 59, but with an added feature to hold all parts together against the expansive force of the compensating spring 63 in the hydraulic chamber. There is provided coacting wedge plungers 60 and BI carrying the load and thrust from the usual push rod 62. A return compensating spring 63 is disposed in a low compression chamber formed at the inner end of the cylinder 58 and maintains the two wedges 60 and 6| in operative compensating engagement.

This form of the invention is especially provided to retain the wedges 60 and 6| within the rocker arm 59, as well as all parts in the compression chamber, before the rocker arm is assembled on an engine or when the push rod 62 or the engine valve 5 is not in place. The expansive force of spring 63 in the arm displaces the parts and the assembly cannot be conveniently maintained until the arm is installed on the engine, and so I have provided the least expensive means in manufacture to accommodate this condition. The lower plunger 6| is carried in its guide 64, which is preferably extended below the lower end of said plunger 6|. A stop 65 is burred or peened over with a suitable tool by forcing inwardly a slight portion of the lower edge of the guide sleeve 64, as shown. This plugged in stop means 65 afiords adequate clearance between it and the lower outer end of plunger 6! so that in operation there is suflicient room for relative compensating movement between the plunger and this shoulder stop 85 forming the assembly retaining means.

Prior to mounting the rocker arm on an engine, or when the rocker arm is removed from the engine or taken off of its rock shaft, or the push rod or valve is removed, the return or compensating spring 63 thrusts the wedge plunger 60 outwardly andconsequently thejwedge plunger 6| down-v wardly until the latter restsagainst the stop 6|, whereupon the parts remain in assembled rela. tion and cannot be lost by dropping them out of the rocker arm or its cylinder 58. Once a rocker arm is manufactured and assembled and installed on an engine, there is rarely, if ever, any reason for dis-assembling the rocker arm and'so I have found this permanently set stop. 65 fulfills the requirements.

In general, this invention provides a valve operation mechanism in the form of arockerarm or lifter having positive oil-intake or priming means by which to prime or charge'its high or 1. A rocker arm, comprising a hub adapted to.

oscillate on a hollow oil-feed shaft, arms pro! jecting from the hub, a cylinder carriedby one of the arms, a piston adapted to undergo compensating movement in the cylinder and setting. off a hydraulic compression chamber in said cylinder, an oil passage leading from the inner end of the compression chamber into the hub, a check valve. in the compression chamber seated over the oil passage, a washer freely insertable in the cylinder and fitted over the check valve to retain the latter in operative position and leaving a limited space for the latter to open and close over the passage, and an expansion spring interposed between the washer and the piston; i

2. A valve. operating rocker, comprising a central bearing hub, a solid arm projecting from the hub, a tubular arm projecting from the hub, an oil passage leading from the hub into one end of the tubular arm, a check valve preventing the flow of oil in the passage out of the tubular arm, a coil spring in the tubular arm having a diameter substantially equal to that of the interior of the latter, a stationary disc having an oil passage seated in the tubular arm over the check valve with limited space between the latter and said disc, a central boss formed on the disc around which the coils of the spring are disposed with one end of said spring bearing on said disc, an oil piston mounted within the tubular arm and urged outwardly by the other end of the spring yieldingly engaging said piston, and a central boss likewise formed on the oil piston and around which fits the last named end of the spring, said bosses and-spring substantially filling the fluid chamber in compressed fluid chamber position.

3. A valve operating rocker, comprising a central bearing hub, a solid arm projecting from the hub, a tubular arm projecting fromthe hub, an oil passage leading from the hub into one end of the tubular. arm, a check valve seated over the passage where. the latter opens into the tubular arm, a coil spring in the .tubular arm have ing a diameter substantially equal to that-of the interior of the latter, astationary disc having an oil passage seated in the tubular arm over the check valve with limited space between the latter and said disc, a central boss formed on the disc around which the coils of the spring are disposed with one end of said spring bearing on said disc, an oilp-iston mounted within the tubulararm and urged outwardly by the other end of the spring yieldingly engaging said piston, and :a central has likewise formed on the oil piston. and around which fits the last named end of thespring, the spring and two central bosses being so prop'or. timed. and formed. that the coils of the spring collapse one upon the other. at the same time the bosses engage each other upon the first operation of' the rocker arm, whereby maximum displacement occurs'in a compression chamber formed between the stationary disc. and. oil piston which fullyclos'e'ssaid chamber preliminary to sucking a charge of oil past the ball check into said chamber.

4. A rocker arm as defined in claim 3, character'ize'd by making said compression chamber relatively small-in volume, the oilcapacity of which is small, whereby the sucked-in charge of oil is small, resulting in occluding a correspondingly small amount of air.

5. A hydraulic rocker arm, comprising 'a bear ing hub carryinga cylinder, a self adjusting pis-' ton mounted in the cylinder forming a hydraulic chamber therein, a valve controlled'oil passage leading to the hydraulic chamber, said piston adapted to reciprocate the full length of the hydraulic chamber to one end thereof upon the first operation of the rocker arm to fully close said chamber and effect complete air displacement therefrom, a boss within the cylinder, and a coil spring disposed inside the hydraulic chamber and around the boss and'reacting against the piston'to return the latter to its original position and suck a charge of oil past the valve into said chambenlthe. coils of said spring being rectangular incross section'and' substantially the size of the *cylinderso that when collapsed against each other the boss and spring substantially fill the oil chamber when the piston completes its airdi'splac'ement stroke aforesaid.

6'. A hydraulic rocker arm, comprising a heating hub carrying a cylinder, a self adjusting piston mounted in the cylinder forming a hydraulic chamber therein, a valve controlled oil passage leading to the hydraulic chamber, said piston adaptedto reciprocate the full length of the hy draulic chamber to one end thereof upon the first operation of the rocker arm to fully close "said chamber and effect complete air'displacement therefrom, a coil spring disposed inside the hydraulic chamber and reacting against the piston to return the latter to its original position and suck a charge of oil past the valve into said chamber,-the coils of said spring being rectangular in cross section and having a diameter substantially that of. the cylinder. and adapted to collapse against each other at the same time the piston completes its air-displacement stroke aforesaid, a stationary disc disposed over the valve and having a boss around which fits one end of the; rectangular cross section spring, and a boss formed on the piston and around which fits the otherendof the spring.

'7. A hydraulic compensating rocker for actuating valves, comprising a hub having arms ex tending therefrom, one of the arms being provided with a cylinder opening thru the outer end of the arm and extending toward the hub, an oil passage leading from the hub into the bottom of the cylinder, a check valve in the cylinder adapted to closethe passage, a disc disposed in the bottom of the cylinder over the checkvalve to retain the latter in place for sensitive restricted movement,

a piston inserted into the open end of the arm into the cylinderand normally spaced inclose compression chamber at the bottom of the cylinder, a cylindrical boss formed on the piston and on the disc in the compression chamber further reducing the volume of the latter, a coil spring in the compression chamber and substantially the diameter of the cylinder, said spring having its ends fitted over the bosses, said spring coils proportioned and arranged to collapse and engage each other when the spring compresses to its limit, and said bosses stopping one against the other to reduce the air space to a negligible amount when the spring coils are collapsed aforesaid.

8. A rocker arm for actuating valves, comprising a hub, a cylinder extending from the hub and open at its outer end, a passage leading from the bottom ,end of the cylinder into the hub, a valve closing the passage, a piston inserted thru the open end of the arm into the cylinder and having its inner end spaced close to the bottom of the cylinder, a compensating spring made of rectangular-cross section coils inserted between the pistonand bottom end of cylinder, and a boss at each end of the spring around which seats the coils thereof, the bosses and the spring coils being proportioned and arranged to simultaneously close against each other at the end of the in-stroke of the piston.

9. A hydraulic self adjusting rocker for actuating valves, comprising a hub with arms extending therefrom, one arm forming a cylinder, a piston in the cylinder forming a compression chamber, an oil supply leading to the compression chamber in the arm, and means including a plunger adjustably disposed in a guide transversely to the axis of the piston and engaging the piston to reduce the working load on the compression chamber by transmitting a major portion of the rocker arm operating force thru the walls of said cylinder to the other arm.

10. A hydraulic self adjusting rocker for actuating valves, comprising a hub with arms extending therefrom, one arm forming a cylinder, a piston in the cylinder forming a compression chamber, an oil supply leading to the compres sion chamber in the arm, an opening formed thru the wall of the cylinder providing a bearing guide transverse to the axis of said cylinder, 'a plunger carried in said bearing guide and coacting with said piston, and means cooperating with the piston and plunger to amplify the movement of the piston and cause it to adjustably move thru a greater range of travel than takes place in the plunger.

ll. A self adjusting rocker for actuating valves,

comprising a hub having operating arms extending radially therefrom, one arm provided with a cylinder formed therein and an oil passage leading thereto, a piston movably carried in the cylinder and setting off a hydraulic compensating chamber at one end of said cylinder, a spring urging the piston outwardly to draw oil into the chamber, and the outer end of said piston being provided with a surface inclined at an angle with respect to the axis of the piston and adapted to be engaged by a cam actuated member to oscillate the rocker arm.

12. A self adjusting rocker for actuating valves, comprising a hub having operating arms extending radially therefrom, one arm provided with a cylinder formed therein and an oil passage leading thereto, a piston movably carried in the cylinder and'setting oif'a hydraulic compensating chamber at one end of said cylinder, a plunger engaging the piston at an angle to the latter, the

piston and plunger having sliding contacting surfaces formed at an angle to the axis of the cylinder, and a spring urging outwardly on the piston and plunger to draw oil into the compensating chamber.

13. A self adjusting rocker for actuating valves, comprising a hub having operating arms extending radially therefrom, one arm provided with a cylinder formed therein and an oil passage leading thereto, an oil seal piston in the cylinder and forming a compensating chamber between it and the bottom of said cylinder, and a pair of plungers operatively engaging each other at an angle, one of said plungers engaging the oil seal piston, and a spring to urge outwardly on the piston to suck oil into the chamber.

14. A self adjusting rocker for actuating valves, comprising a bearing hub and two oppositely projecting' arms, an oil feed passage leading from the hub along one of the arms, this latter arm bored from its outer end to form a cylinder the bottom end of which connects with the passage, a ball check valve in the bottom of the cylinder normally closing the passage against oil flow out of the cylinder, a stationary disc at the bottom of the cylinder holding the ball close to its seat passage, a coil spring in the cylinder having one end seated on the disc and its other end expansibly disposed in the cylinder, an oil seal piston in the cylinder and engaging the spring, an operating plunger in the cylinder and having its front end engaging the piston, a wedging inclined plane formed on the rear end of the plunger, an opening formed in the cylinder toward its outer end and under the wedging inclined plane, and a second plunger slidably confined in the opening and having a wedging surface which engages the first named plunger.

15. A self adjusting rocker for actuating valves, comprising a bearing hub and two oppositely projecting arms, an oil feed passage leading from the hub down one of the arms, this latter arm bored from its outer end to form a cylinder the bottom end of which connects with the passage, a ball check valve in the bottom of the cylinder normally closing the passage against oil flow out of the cylinder, a piston disposed in the cylinder closely spaced from the inner end of said cylinder and having a short self adjusting stroke thereby forming a small volume compression chamber, said piston adapted to move to the end of the cylinder upon the first operation of the rocker arm and fully close said small volume compression chamber thereby displacing the air therefrom, a spring to return the piston to its outstroke position and suck in a charge of oil into the chamber, a wedging face formed on the outer end of the piston, and an operating plunger carried by the rocker and also having a wedging face which engages the similar face on the piston.

l6.A hydraulic rocker arm for actuating valves, comprising a hub having arms extending therefrom, a small volume compensating oil chamber formed in one arm of the rocker and an oil supply line leading to said chamber, a piston plunger working against the small volume body of oil in the chamber, said plunger arranged to undergo a full in-stroke and attain maximum displacement to close the small volume chamber upon the first operation of the rocker arm, a spring to return the plunger to its out-stroke position thereby sucking a full charge of oil into said small volume chamber, and a plunger coacting with the piston plunger and engaging each other on an angle to the axis of each to reduce the" operating load on thesmall body of oili'n the chamber. V I j p 1-7. A hydraulic selfadjusting'rocker' arm, comprising a hub with arms, a cylinder formed in one arm and an oil 'passageleading thereto, a pistonin: the cylinder'which sets offacompression chamber therein, said piston having a wedge face'on: itsouter end, a plunger disposedl at right angles to. the;pistoni.and also: having a .wedge face engaging the wedge face of said piston, said wedgev faces being formed on a plane at substantiallyaforty-five degree angle in relation to the axis of the piston or plunger whereby the. adjust ingtravel is the same for both the piston and the'pl'uiiger thereby imposing high pressure on the compression chamber, and spring means to urge outwardly on the piston and plunger.

18. Valve operating mechanism comprising a hydraulic device employing mechanical means in aid of self adjusting action, comprising an operating member adapted to be interposed between a cam and an engine valve, a hydraulic oil chamber in the operating member, wedge-like plunger means cooperating with each other and working against the oil in the chamber; said wedge-like plunger means including coacting parts slidably thrusting against each other on substantially a forty-five degree angle in relation to the direction of the adjusting movement thereof, whereby substantially the full load of the cam and engine valve is carried on the oil in the chamber.

19. A hydraulic rocker arm, comprising a central hub having arms extending therefrom, one arm being provided with a cylinder, a piston in the cylinder, an oil supply passage leading into the cylinder in front of the piston, a plunger engaging the piston with an inclined operating face made on an angle to the piston axis, the plunger having a push rod operating connection by which a cam and push rod are adapted to oscillate the rocker arm by a tilting force applied to said plunger, an oil groove made in the inclined operating face and adapted to receive oil which leaks by the piston, and an oil hole extending longitudinally thru the plunger and receiving oil from the groove and leading said oil to the push rod operating connection.

20. A hydraulic rocker arm, comprising a central hub having arms extending therefrom, one arm being provided with a cylinder, a piston in the cylinder, an oil supply passage leading into the cylinder in front of the piston, a check valve permitting oil to enter the cylinder and preventing oil from passing out therefrom, a plunger engaging the piston with an inclined operating face made on an angle to the piston axis, a spring expanding against the piston to urge it and the plunger outwardly from the rocker arm, and means engaging the inclined operating face to retain the piston and plunger in the rocker arm against the force of the spring.

21. A hydraulic rocker arm, comprising a central hub having arms extending therefrom, one arm being provied with a cylinder, a piston in the cylinder, an oil supply passage leading into the cylinder in front of the piston, a plunger engaging the piston with an inclined operating face made on an angle to the piston axis, a spring expanding against the piston to urge it and the plunger outwardly from the rocker arm, and stop means engaging the plunger to limit its outer stroke to retain it and the piston in the rocker arm.

22. A rocker arm including a cylinder formed in one of its arms, a hydraulic compensating unit carried:i'n the cylinder and having a compression spring to actuate the unit, an opening formed thru the [wall of the cylinder and forming a'"sleeve made onct'he rocker arm, a plunger mounted in the sleeve and extending thru the opening into the cylinder and engaging the compensating unit with the outer end of saidplunger disposed with-j insaid s'levegarid stop means on the outer end of the sleeve against whichthe plunger is held infposition and preventedifrom dropping' o'ut of therocker arm dueto'the'forc'e of the spring. 23; A fro'cker arm including a cylinder formed in one oflfit sarms, a hydraulic compensating unit carried the cylinder and having I a compression spring tda'otuate the'unit," an opening formed thru the wall of the cylinder and forming a sleeve made on the rocker arm, a plunger mounted in the sleeve and extending thru the opening into the cylinder and engaging the compensating un1t with the outer end of said plunger disposed within said sleeve, and a stop made on the sleeve by deforming its outer extremity inwardly in line with the plunger to keep it in position against the force of the spring.

24. A rocker adapted to be actuated by an engine driven cam to operate a valve, comprising a member having an opening, a compression chamber in the opening of the rocker and an oil supply connected therewith, plunger-wedge means carried in the opening and operating against the oil body in the chamber, and a spring acting on the plunger-wedge means to adjust same in one direction, said plunger-wedge means being adapted for operating connection with the cam.

25. A rocker for operating valves, comprising a central hub adapted to oscillate on a rock shaft under the force of a cam, a pair of arms extending therefrom, a hydraulic self adjusting unit carried within one of the arms and including a hydraulic compression chamber in said arm, an oil supply leading to the hydraulic compression chamber, and coacting straight smooth-faced wedges having relative sliding motion against each other included in the self adjusting unit and operatively mounted within said arm and cooperating with the hydraulic compression chamber to reduce the operating cam and Valve load and pressure on said chamber.

26. A hydraulic rocker arm adapted to be actuated by an engine driven cam to operate a valve, comprising a member having an opening, a hydraulic compression chamber in the opening of the rocker arm and an oil supply connected therewith, plunger-wedge means carried in the opening and operating against the oil body in the chamber, and a spring acting on the plunger- Wedge means to adjust same in one direction, said plunger-Wedge means including one wedge member which is slidably carried within and which projects through the rocker arm and is adapted to be directly engaged by a cam-actuated push rod.

27. A self-adjusting hydraulic rocker arm for actuating engine valves comprising, in combination, a hub adapted to rock upon a hollow shaft which transmits oil to said hub, actuating arms extending from the hub, a bore in one arm forming a cylinder therein, an oil passage formed through the hub leading to the cylinder, a free check ball valve in the passage to admit oil into the cylinder and seated by pressure of said oil, a retainer over the free check ball valve to hold it in place and limit its movement; plunger means in the cylinder serving, when in normal operative self-adjusting position, to occupy or fill the space in said cylinder excepting a substantially small cylindrical portion thereof, which small cylindrical portion forms a hydraulic-pressure chamber of minimum size having a restricted volume set ofl to hold a minimum amount of oil trapped between the check-valve retainer and the plunger means; the inward movement of said plunger means, toward the check-valve retainer, serving to completely close the minimum-size hydraulicpressure chamber by reason of the plunger means stopping against said check-valve retainer, thereby discharging a maximum amount or substantially all of the air from said minimum-size hydraulic-pressure chamber, by virtue of the single inward stroke of said plunger means displacing or reducing to nil the restricted volume of said chamber; whereby a single outward stroke of said plunger means, in returning to its normal opera.- tive self-adjusting position, acts to draw a solid charge of oil through the passage into the airfree minimum-size hydraulic-pressure chamber to very efiectively fill same; and a compensating spring cooperating with the plunger means urging the latter outwardly away from the check-valve retainer, said spring and its cooperating means being so constructed and arranged that it contributes to the filling of all spaces in the hydraulic-pressure chamber to exclude the air therefrom.

ROBERT C. RUSSELL.

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