US2940433A - Hydraulic valve tappet - Google Patents

Description

2 Sheets-Sheet 1 Filed Dec. 1, 1958 II 1111111111 I",

June 14, 1960 G. T. RANDOL 2,940,433

HYDRAULIC VALVE TAPPET Filed Dec. 1, 1958 2 Sheets-Sheet 2 United States Patent HYDRAULIC VALVE TAPPET Glenn T. Randol, P.0. Box 53, 2nd and Paul Sts., Mountain Lake Park, Md.

Filed Dec. 1, 1958, Ser. No. 777,327

15 Claims. (Cl. 123-90) My invention relates to valve tappets or lifters adapted to automatically maintain substantially zero clearance in the valve drive train of an internal-combustion engine, and more particularly, the invention is concerned with improvements related to and associated with the valve tappet construction disclosed in my US. Patent No. 2,695,013 issued November 23, 1954.

The improvements above referred to comprise: a checkvalve of novel construction in the shape of a hollow frustum of a cone to provide added rigidity against distortion under the high pressures to which-it is subjected, and therefore affords improved sealing characteristics under all operating pressures; a non-metallic abutment element carried atop the conical-shaped check-valve normally in circular alignment with a ring-type non-metallic element embedded in a suitable recess which encircles a passageway through the lower closed end of the plunger. reservoir, to silence the impact of the inertia hammer or weight to move the check-valve to open said passageway to accommodate relative adjustment between the principal body members of the tappet; and a central stem on which the inertia weight slides is fixed on the plunger cap separate from the check-valve enabling the inertia weight to slide relatively to the stem into and out of engagement with the upper face of the abutment atop the check-valve under influence of a conically-shaped expansion spring encircling said stem above the weight with said spring reacting between said weight end portion of said stem adjacent its attachment to said plunger cap.

In a modified construction, the central stem is fixed at one end to the check-valve and a portion of the other end is slidably supported in a centrally disposed bore in the plunger cap whereby the inertia weight is capable of sliding relatively to and in unison with the stem and engages the check-valve to move simultaneously therewith to open it. Accordingly, the action of the aforesaid encircling conical spring is also modified so that it moves with the stem and relatively thereto in response to like movements of the inertia weight in controlling the checkvalve.

A more specific object of my invention is to provide a commercial design of the structure shown in my patent above referred to, so that the novel concepts disclosed may be marketed as original equipment or through aftermarket channels as a replacement product.

' Objects and advantages not specifically set forth hereinbefore will be noted in the course of the detailed description of the invention to follow with reference to the accompanying two sheets of drawings, wherein the preferred embodiment and a slightly modified embodiment are illustrated:

Figure 1 is a fragmentary longitudinal sectional view, partly in elevation, of an internal-combustion engine and its valve drive gear or linkage, the view demonstrating the disposition of the present self-adjusting tappet assembly between the engine camshaft and the lowerend of the push-rod included in said linkage; a

Figure 2 is an enlarged longitudinal sectional view through the tappet assembly of Figure 1, with the camshaft disposed substantially 90 to the plane of this longitudinal section;

Figure 3 is a view similar to Figure 2, exhibiting the changed status of certain parts of the tappet assembly in response to another position of the camshaft to effect opening of the corresponding engine valve; and

Figures 4, 4A and 5 are longitudinal sectional views of a modified embodiment of the invention showing operational sequences similar to Figures 2 and 3, said Figure 4A being a fragmentary view of Figure 4 on an enlarged scale for clarity of detail.

Referring now to the drawings, and particularly to Figures 1, 2 and 3, my invention is shown incorporated in a conventional internal-combustion engine designated as a whole by the letter B which has a plurality of poppettype valves one of which is shown at 10. A valve drive gear or train, indicated generally at-l l, is provided for each valve of the engine, and is conventional in all respects except for the valve tappet mechanism of the present invention, which is embodied therein. The valve drive train 11 extends between the valve 10 and the camshaft 13 of the engine. The valve 10 may be of any known construction and that selected for illustration includes a stem portion 14, guided in a collar 15, and having normally preloaded spring means 16 associated therewith normally tending to close the valve. A rocker arm 17 pivotally mounted intermediate its ends on a suitable rock shaft 18 is adapted to bear atone end 19 thereof against the free upper end of stem 14 when rotated in a counterclockwise direction as viewed in Figure 1, to open valve 10 against the force of spring means 16. The other end 20 of the rocker arm 17 has a hemispherical recess (not shown) in its under surface to accommodate the outer complemental end of a push-rod 21, the other end of which bears against a dished fitting disposed in the upper hollow end of a valve tappet generally designated T constructed in accordance with the present invention and which will now be described in detail.

The valve tappet T, which is of cylindrical construction, is illustrated as slidably mounted in a bore 23 radially disposed, in respect to the axis of the camshaft 13 in the block of the engine B so that the inner end of the tappet T bears on the surface of the cam 25 allotted thereto.

Referring now to Figure 2 for a more complete understanding of the structure and functioning of the valve tappet T, it will be seen that each of these comprises: a first principal element disclosed as an outer body or shell 26 having a working fit in its bore 23 in the block of the engine, and having a closed bottom end 27 engaging the surface of the cam as seen in this figure. A second principal element of the tappet is disclosed as a telescopically-related plunger 28 of cup-like form, the outer cylindrical surface thereof sliding with a substantially oil-tight fit Within a complemental longitudinal counterbore 29 in the shell part 26. The plunger 28 is closed at the bottom by a wall 36 having a centrally disposed downwardly projecting spout 31 provided with a passageway or port 32 therethrough. A compartment or high pressure chamber 34 is seen to be confined between the walls of a longitudinal bore 35 which terminates the inner end of said counterbore and the inner end wall 39 of the plunger 28, which chamber when appropriately filled with oil and closed by a movable member or check-valve designated CV over the port 32 functions as a solid medium to cause lift of the valve train by the cam acting on the bottom wall of the shell 26. The upperend of the plunger 28 supports with a snap-fit a push-rod thimble or cup 37 fitting within its bore and having a circular flange 38 overlying the upper end of the cylindrical wall of the plunger. The dished CV is open thus disabling the function of the chamber 34 as a solid medium.

Operation of the valve tappet mechanism T of the first embodiment of the invention is as follows: With the engine valve in closed position as shown m Figures 1 and 2, the various elements of the mechanism T assume relative positions as illustrated in these figures. Here the spring 63 between the tappet body 26 and plunger 28 expands the tappet in length between the push-rod 21 and the base circle 90 of the cam 25 on the camshaft 13 so that the lower bottom end 27 of the tappet body 26 bears thereon with substantially the force exerted by spring 63. The entire assembly T is charged with oil from the pressure lubricating system of the engine, as previously explained, such that any air initially trapped in chamber 34 is slowly vented through leakage between the plunger and bore of the tappet body and replaced by oil during operation. The strength of spring 55 is preferably less than spring 74 plus the static weight of the inertia element 75 which enables the checkvalve CV to assume an open position as best demonstrated in Figure 2 when tappet motion ceases. Thus, the check-valve is held lightly away from its seat 53 by such differential forces acting on opposite sides of the checkvalve, so that the volume of oil in the chamber 34 may decrease or increase by flow'through the open port 32 connected to the reservoir 41. This change in volume of oil in chamber 34 results from shortening or lengthening of the relative disposition of the tappet body and plunger to compensate for backlash, if present, in the valve drive gear, whereupon closure of the check-valve by the inertial eflect on the weight 75 in response to the lift portion of the tappet cycle traps the adjusted volume of oil in chamber 34 to act as a solid body on the valve drive train to open the selected engine valve 10 as is understood. As cam 25 rotates in a clockwise direction as viewed in the figures, the opening ramp 91 thereon which merges with the base circle with the lift, operatively engages the underface of the bottom wall 27 of the tappet body 26 and begins to lift the same either with a quick lift, if the cam contour is designed for the conventional type of hydraulic valve tappet, or with a slower more gentle lift if the cam is especially designed for the tappet of the present invention. Under these circumstances movement of the tappet being resisted by the engine valve spring means 16 through the pushrod 21, tends to apply pressure on the solid mass of oil in the chamber 34 between the tappet body 26 and plunger assembly 28 which imparts a pressure or hydraulic impact to the .underside of the check-valve CV which is normally minutely spaced from its seat 53 in open condition upon closure of the engine valve, and forces the check-valve CV to tightly close, best demonstrated in Figure 3, thereby imprisoning the oil within the chamber 34 in a sufliciently solid acting mass to cause the parts of the tappet T to move in unison and thus lift the engine valve 10 from its seat as though a solid tappet were in place. The engine valve train clearance having been substantially zero at the position indicated by Figure 2 because of the action of the expanding spring 63 between the two tappet body elements, the action in operating the valve drive train is that of a mechanical lifter with substantially zero-lash present.

When the cam opening ramp first engages the underface of the tappet, all parts associated therewith are given a rapid upward thrust including the inertial weight 75 to tightly seat the check-valve CV without flexing it due to the frustoconical design thereof. Being unrestrained in its movement except by the light conical spring 74, the inertial member 75 moves more rapidly than the other parts of the tappet assembly under the initial impetus'and thus compresses the spring 74 so that the inertial member moves, for example, up to the position illustrated in Figure 3 wherein its lower face is seen to be spaced well away from the upper closed end 51 of the d check-valve CV; This condition obtains at least until the cam 25 reaches its position of maximum lift as illustrated in Figure 3 and during this movement the inertial member is compressing the spring 74 and the spring 55 is assisting the pressurized fluid in chamber 34 to hold the check-valve tightly sealed on its seat 53 against any tendency, such as might come from vibration or the like, to unseat it, thus insuring operation for this part of the tappet cycle with substantially zero backlash and absolutely quite operation of the engine valve train.

As the cam 25 progresses from maximum lift point 92 demonstrated in Figure 3 to the released or engine valve closing ramp 93 position, the tappet T is lowered and with it the engine valve 10 is closed by action of spring means 16 best demonstrated in Figure 2. Under these circumstances the downward movement of the tappet leaves the inertia hammer 75 in the Figure 3 position momentarily thus imparting lift to the inertia member until the tappet body 26 rides off of ramp 93 onto the base circle 90. Here, conditions reverse themselves, the downward movement of the tappet T ceases, the inertia of the member 75 no longer is sufiicient to overcome the expanding action of the spring 74 and flue weight of the member, both under influence of gravity and the pressure of spring 74, moves the inertia member 75 rapidly downwardly into impact with the closed end 51 of the check-valve CV and thus drives it from its seat as shown in Figure 2, despite the still considerable pressure which may be behind it, thereby establishing fluid communication between the chamber 34 and oil reservoir 41 whereby an appropriate movement of oil in the required direction take place. The springs 55, 74 are so weighted that at periods of tappet rest the latter spring plus the weight of the inertia hammer 75 substantially counterbalance the former whereby the check-valve CV is delicately held open. It is thus seen that rating the spring 55 to overcome the static weight of the inertia hammer 75 and reaction from the spring 74 that the check-valve CV may be caused to assume a lightly closed condition with the tappet T at rest, or by rating the spring 74 plus the weight of the inertia hammer 75 to overcome spring 55, the check-valve may be established in a full open poistion of Figure 2. Accordingly by varying the weight of the inertia hammer 75 and the weight of springs 55, 74 different adjusted positions of the checkvalve CV with respect to its seat 53 may be had according to the timing and sensitivity of operation desired as may be dictated by the particular engine in which my invention is to be incorporated.

It is important to observe here that the variations discussed in the paragraph next above regarding the strength of spring 55 produce corresponding changes in the axial position of the inertia mechanism 1M following impact to open the check-valve CV, while the tappet T is riding the base circle of the engine-driven cam 25. For example, if the predetermined status of this spring is less than the combined static weight of the inertia hammer 75 and expanding action of the spring 74, then the checkvalve after being opened to the position of Figure 2 by the downward throw of the hammer 75 accelerated by the spring 74, would remain in this position while the tappet T is at rest riding the base circle of the enginedriven cam 25, but were the pretensioned strength increased sufficiently to support the static weight of said hammer and expanding action of the spring 74, then the check-valve CV would recover from the position of Figure 2 induced by the impact of the hammer 75, to a position closer to the seat 53 or lightly engaged therewith in readiness for another lifting action by the cam 25 to open the selected engine valve 10. Thus, the sensitivity and timing of operation of the check-valve may be varied from wide open to closed positions by varying the relative pretensioned strengths of springs 55, 74 in relation to the weight of the inertia hammer 75, during the base'circle cam contact with the tappet body 26. Inthis r l t igh e the ehshfh at manner, greater or less portionlof the initial portion hm am 23- m e -ed e ih e the ii t-phr ieii 51i mapper v lekand the e ore, he cl ser ferbaekto :the'reservoir .41; or if as a result of ttempera it 7 t lillit changes or wear'in the valvedriveltrain, there has been ,an accumulated. backlasnthis is immediately taken render action of the spring L63 forcing the tappet T to'elongate' andaagain reducewthe clearance to'substantialr t t lyre re. The slightly tendency of the check-valve CV to open underiinfiuence of its own inertia is very material ly augmented by the :action of the hammer blow of the inertia member 75 rmoving under the impetus of its spring and thus'cornplete opening of the check-valve is assured t nder circumstances so that, full compensation may be ni ade for clearance adjustment during each'tappet-cycle.

Thecheclc-valve CV is held Iopen under the conditions shown in Figure 2 during a substantial degree of the arc dnringwhich the tappet body 26 is riding on the base sir le 0, b the mem htu e d 011 eh mmer is lcstprier 1Q approaching the opening ramp 91 so that 'i helcllecli-valve CVnis :substantially'unloaded in readieess r th spring eh ehshi dr uli i e i whenrh tappetli s hxh s r hi r eo eh e en ihe I It is thus-app eciat d t t f heti h h i t lh et emhc ment (F r :3) o my in on P Q lQ m xinrum efiiciency of the hydraulic valve tappet I under circumstances and that substantially zero-lashis kachieyedjnthe valve drive gear during the whole time that the engine valve is opening and closing. After the 7 engine valve 10 closing and when the tappet check-valve 'CV-is open as shown in Figure Z there is some slight; relief of pressure on the, heel or base circle 90 of the cam so that minimum Wear resttltson thecontacting parts.

"With .the tappet ch ekalve w(3V open n and clo ng once per cycle of the tappet, carefuimodulation and adjustrnentof the whole yalve' train i s achieved that many times, s9 that the backlash or clearancein the whole train is'vmaintainedt-asnearzero as'tfeasible and desirable, all a with the addition of only a few simple and low-Priced partsfto what has beennconsidered as the normal or commercial type of hydraulic y'alve'tappet.

Mpdifie d inertial mechanism and operation This second embodiment of my invention ,is illustrated in Figures 4, 4Aiand 5, and in which correspond- ;ing partsvaredesignated bylike reference numerals .distinguished, however, by the addition of the letter a to each.

This modification difiers essentially from the first disclosure in the interaction of thetrod 70, the check-valve .CV and the inertial hammer 75 including the latters spring 74;

II'heupper end of the rod a is slidably disposed -,in

, -portion prejects through a hole'in the non-metallic disc 7 81a andthe up per endj wall' Slaof the: chech valve 6V 7 1e ris dly s eh' eirhr s tege her a hy P hihs er ete pc ticn'to fe mp head e d wan 51a,v Thus the u l'ii p i e fifi i eh; V. t perehl zd peeed be wee t e hppenteeeofnle inertia @5191 i the seeie l ill consequent {m nimumreintroductionjdi l eiu t d l n th c flt pp t I 16 emeve hhsia it rate 54 Whil ins he. fir "embodi nt; thi use ng wi h th i luhsericap i374 and pansion spring 74a.to add accelerating movement In the p in .4 he 'ehl lne e wirh the nod" ,oizi but .is tee hress rl elativel t he et :h t e ine ti l et h ehlhe ham e dur ng its upward throw. Accord y; the 39 r; thre -5 or 'tncvement p the i ertialjhammer l e th ehsh' e's r hs 4.10 supp e n th a t v 'e esm a5 e to closethe.valveasshown .i sfig rei1jnsnch tclcsmept the "checkwalre cv is e dediby th tinert el efi t qnthe' dme 1 Th dcwnwardthrgw o theinertia-ljwe sh .5a isv n iaddedeecel retio h 't cem e sed. s ri 4a tQt I e the va fleh rile'i ohh s 'compl ht h s a 534 men the chee -va ve C a he ehdhf. hetclosipgpn igh set th ta p tey as sheen in F e 4 ter nehleth 1.- lin ambe s-Matte very ill a l eeklesh from h va d v ar s ire l d r teedv is thus seenl at n t e pr sen me eatieh Q? my i ent cn h rqd Nameves withh h c e k-YelveQ while in th firs d e e ur s wn i Fi ures 1:34 te'lhs e th s em 9 sls pe at fremthe-ehee -va eLC n a t ched nly t the, 'plunse tc p 37a f r mevexhsnt the ewi h. Alsofitsho b obs ve tha h ine al Spf fi gi r a i .thsem odihi h mo es with h e 'wq arid relat ely th reth un e jihfihehe e lhemert e them' 3. red unde influ nce h "the v ine t mme "Thi modification is epera ienal vs h j er to -.theifirs embpdiment in. e p ct t the t m g andisensitivity :9; fipfilation of the c ec valve CV, h c may h varied by changing the relative weights of the'springs55q; 74g and the weight 0f the inertial hammer 75a. jForexamp e, Figu 4 sle onstratesthe stati e ghts. ot he stem 11a, iner;tial hammer 75a 'andjspringi ua tribe greater. than the expansive vforce of the check valvespring 5.5 i hh tappet substantially re t thus establishin .thecheck-valve intull open position, bntif the force of the VspringYSSa were increased sufiiciently tor supportthe static weights of the above. three part .then .llPQ l #31239 e lheihe t l hemme 5e i h h eekel i fil and then the embedded abutmentwasher;72a, .the actign 9f sn hs55a e th pe rides t e-bas e ele 2 49 the cam 25a; wouldbqto, recover the inertiamechanisrn ,IM until the valve' -flange 52a lightlytengages its con}.-

.plemental. seat 534 inreadiness' forthe hydraulicimpact to tightly close the eheckwalve and thus convert ,the'taprpet T into a solid body to open-the selectedenginefyalye 10. Accordingly, this "modification; with the tappet riding the b e s rele fi -Weh establish t ine l h mmer in e e en wi h h r u eh -weeh rwa and the checkrvalve fully open astdemonstrated by Figure .4, or under the circumstances of the check-va1ve; spring 5511 being weighted to support the static weight of the inertia mechanism I'M, thelatter would recover the-position of so its hammer 75;: being spaced above the abutment washer jQehhdthe heeh v 1 ht1v e d elo edhee flea eh h ras n 9 the h mm i e h et rmine b the mo ement e the ehee se e f m wid r h h Pe on t u v l ed eei ehih e ene eth dewhw c5 im ac e th hammer r -.e en th eheekelve eed-t ;rec0ve '-Vh@l'Qi e1 wi th ne ti m ehehiehi 10 an intermediateposition wherein the checker/Valve ensese its se t .534 T hs hv e ih l 5Pi 1 4 ahiei h v h a it ehld h t eb 9 ree e i th s .i a v Q l htl closed :C lldl l nafter wi r tiQ Iih he d b he-d a d m a t ti m le e1 1- eh M- e h te p t mec an m 1 ride th ar 20a. o' h e T 2 nd n i t 'ihehsura im e 1 when e the appet ey enarrates the tappet T operate to eliminate any backlash in the valve drive train, and both function during the time that the tappet is riding the base circle of the engine-driven cam. The first of these is the expansion spring 63 tending to separate these two elements or actually elongate the tappet, and the second is the pressure on the oil from the engine lubricating system endeavoring to enter the chamber 34 after the check-valve CV is driven from its seat 53 by the impact of the inertial weight 75.

The present invention is particularly adapted as a replacement item for all valve tappet mechanisms whether mechanical or hydraulic. While it is preferred that the cam design be conventional, as shown on the drawing, it is clear that the present invention will operate efl'iciently with the particular cam design presently used for commercial hydraulic valve tappets where the opening ramp imparts a rapid rise to the tappet in order to provide the hydraulic impact on the check-valve CV to insure closure thereof substantially at the instant of initial tappet lift to prevent reintroduction of backlash in the valve drive gear during the opening cycle of the tappet T.

In the terminology used in the foregoing description and in the appended claims, the identifying expressions and/or terms employed are intended to convey meanings which include the range of reasonable equivalents in the patent sense. For example, the expressions member, body, plunger, shell are intended to include any liquid filled casing and/or chamber having a pressureresponsive movable assembly therein, whether such assembly includes spring action, or some other force serving the same purpose. The terms top, bottom, upward, downward and other directional words or characters are intended to have only relative connotation for convenience in describing the structure as illustrated, and are not intended to be interpreted as establishing any definite position of the tappet T or requiring any particular orientation with respect to associated structure external to the present disclosure.

It will be apparent that various changes, modifications rearrangements and substitutions may be made in the particular apparatus illustrated and described herein vw'thout departing from the scope or fair meaning of the subjoined claims.

Having thus described my invention, I claim:

1. A hydraulic valve tappet having a pair of relatively movable telescopically-related body members defining a liquid chamber therebetween, a source of liquid, a normally preloaded compression spring for biasing said body members apart and accommodating their movement relatively toward each other, a valve port in one of said body members normally open to establish'liquid communication between said source and said chamber, the improvement which comprises: a movable check-valve having a hollow conical wall portion terminating at one end in an outturned annular flanged face and the opposite end being closed by an end Wall; a valve seat encircling said valve port for engagement by said flanged face to close said valve port in response to pressure buildup in said chamber; a normally preloaded compression spring for biasing said check-valve face toward seated relation with respect to said valve seat to close said valve port in cooperation with said pressure buildup; a depending stem rigid with said ported body member and disposed coaxially with respect to said body members; and inertia means including a movable element having spring action in one direction slidably disposed on said stem and elfective on the closed end of said check-valve to open the same by displacing its flanged face out of engagement with said valve seat during the relaxed portion of the tappet cycle whereby relative adjustment between said body members is accommodated.

2. A hydraulic valve tappet according to claim 1 plus means for limiting displacement of the two body mem- 10 here under influence of thefirst-mentioned spring prior to installation in operating disposition.

3. A hydraulic valve tappet according to claim 1 in which the said stem is rigidly attached to said checkvalve for movement therewith and is slidable in a hole centrally disposed in the ported body member.

4. A hydraulic valve tappet having a pair of relatively movable telescopically-related body members defining a liquid chamber therebetween, a source of liquid, a normally preloaded compression spring for biasing said body members apart and accommodating their movement relatively toward each other, a valve port in one of said body members normally open to establish liquid communication between said source of liquid and said chamber, the improvement which comprises: a movable check-valve having a hollow conical wall portion disposed in said valve port and terminating at its lower end in an outturned annular flanged face and the upper end being closed by an end wall; a valve seat encircling said valve port for engagement by said flanged face to close said valve port in response to pressure buildup in said chamber; a normally preloaded compression spring for biasing said check-valve face toward seated relation with respect to said valve seat to close said valve port in cooperation with said pressure buildup; inertia means comprising a weight slidably longitudinally of the tappet relatively to the ported body member; and an elongated depending cylindrical rod rigid with one of the body members for slidably guiding the weight to strike the closed end of the check-valve to-open the same against its biasing spring when tappet motion stops during the closing portion of the tappet cycle.

5. A hydraulic valve tappet according to claim 4 including spring means positioned in encircling relation with respect to said guiding stem above said weight to be compressed by said weight during upward movement of the tappet cycle.

6. A hydraulic valve tappet according to claim 5 in which said spring means is operably disposed between an abutment rigid with the ported body member and the said weight.

7. A hydraulic valve tappet according to claim 6 plus a non-metallic washer embedded in a counterbore terminating the upper end of said valve port for silencing the impact of the downward movement of the weight in opening the check-valve.

8. A hydraulic valve tappet according to claim 7 plus a circular non-metallic disc carried on the outer surface of the end wall of the check-valve, the upper face of said disc being in circular alignment with the upper face of said embedded washer aforesaid when the weight is at the limit of its downward throw to place the checkvalve in open disposition.

9. A hydraulic valve tappet according to claim 8 in which said spring means comprise a conical spiral spring encircling said guiding stem on which the weight is slidable.

10. A hydraulic valve tappet including a cup-like outer body member for cam-actuated reciprocation in an engine block, a cup-like inner plunger member reciprocably disposed in said body portion to define a liquid chamber therebetween, a normally preloaded expansion spring operably disposed in said chamber tending to enlarge it, a push-rod cup carried atop of said plunger to provide a liquid reservoir therein connectible to a source of liquid, a port in the bottom of said plunger normally open to connect the chamber and reservoir, the improvement which comprises: a check-valve of hollow frustoconical configuration having an upper closed end and a lower open flanged end located in said port for cooperating with the latter to close it; a spring cage carried on the underneath side of the bottom of said plunger; a normally preloaded expansion spring operably disposed in said cage for biasing said check-valve to close said port; and an inertia weight effective to bear on the upper closed 994 9 .9??? sheds-va r n i t a r smn Q QP inent o f the ap et.

' 11'; In' ahy d au lic compensating valve tappetforin- -ternal-co nbnstion engines including a earn-actuated tappet hoqy having a longit'uqinal cylindrical bore closed at one endland open at the other, a hollow plunger assembly --reeiprocable in said bore and providing a l-igni i reservoir, a source of liquid, spring means incluqing a normally 'tappet 'body and pinn'ger assembly relatively to each other, a iiquid chamber provided between-the closed end 'of said tappet body ang'the' 'inner'end of sa i 1 plunger assembly; a valve port in the inner end of said phinger m igling said weight forreciprocatiqn omtheaxispf ninve 7 preloaded compression springfor axially elongating sai1 assembly, said port terminating in a'v alve seat; and

"adapted when open to intereoniiectf seid liqtiid reservoir an de e the mp eme l eh Winn e 39int wardly opening check-yalveof hollow frnstoconi calconfiguration having an upper elo s e; ifend"an gr lower tejfirni nating flange engage giblewith said v a l ye seatptofclose said valve port; spring means ineluding anorm aily preloaded expansion spring forbiasin g" said eheek-vfllve nge into engagemenfwith s aid valveseatto close said -"va1v'e*port; and inertia means operably associated with s e a v i i p e was l downward movement ofsaid movable elenaentii ntp impact with the'closed end of said check-valve to op en the valve port substantially at the arre steq point of'tafipet motion.

-13. A hydraniic valve teppet according to claim "12 in which theiner t ia rneans inclutie n eansforsilencing andiirniting the effectiveness offthe movable eleinent on the check-valvein antopnin direction} l i 14. A hydraulic valve tappet accorciing togel aim 12 in which the second-narnecisjiring rneansjare'e fi ctive to snbstantially counterbalance *the third-garnegi spring nteans andstatic weight of said movahie element at sob stantiaily closed position of said" check-valve to nori 'v 0168s k e e Y W y fi'w lw .tsPP l d A hydraulic valvetappet according'to claim 12 in which the secongi-named sp rin grneans are-incapable of overcoming the third-named spring means andstatic weight of said movable elen'rent whereby said checkvalve Im Il t v v t he "fli me;

body at rest.

Ref eren'ces Cited in the file of't'his patent UNITED STATES PATENTS I .zni inis .R n seventies: -,;2,7f}5,39-1 -5Vink1ert --,----t- -iMay-15, 1956

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