US1790998A

US1790998A - Vaiate-operating mechanism

Info

Publication number: US1790998A
Authority: US
Publication date: 1931-02-03
Anticipated expiration: 1948-02-03

Description

Feb. 3, 1931. J. N. PERKINS VALVE OPERATING MECHANISM Filed April 4, 1930 INENTQR W'Perfiivm,

ATTONEY Patented Feb. 3, 1931 7 JOHN NICHOLAS rnaxms, or mcnmoivn, VIRGIN A VALVE-OPERATING MECHANISMI I Application filed April 4,1930. serial no. 441,65?

My invention relates to means for effecting operation of the valves of an internalcom- .bustion engine. Heretofore it has been the customary practice to leave a slight clearance between the valve stem and the tappet or between the push rod and tappet, as the case may be. Due to this clearance the action i of the valve mechanism is noisy (the clearance increasing with wear), the :volume of noise 10 generated being proportional in large measure to the degree ofclearan'ce pI'OVllEd,b6- I tween-the parts.

Many attempts havezheretofore been made 1 to solve the PIObiQl'll of overcoming suchobjectionable feature". All these attempts with which I am familiar appear to have been lacking in one or another particular SlIlCE none of them seem to have come into substantial I use in the art.

20 I It is an object of my present. invention toprovide means always to maintain contact between the valve stem (or pushrodfand the] tappet and to make provision to allow for expansion and contraction and-gtalie upv wear-'1? .2 of parts automatically.

Further, itis an object to provide an improved valve tappet' embodying certain fea.

tures in virtue of which the valve noise so frequently accompanying the running. of an internal combustion engine is practically en-j..j I I the tubular body l while the face 9 normally tirely eliminated.

Further, it is an object designed to permit theireifective lubrication through the usual lubricating system of the I clutclnng surfacell cont nuously incontact I engine, i. e., requiring no special provisions for lubricatlon.

Otherobjects will be'in part obvious and egin part bepointed out; hereinafter. r

in the novel details of constructiom comb} and'is provided with an internal 'conicalexa to providera valve tappet containing the advantageous features aforesaid in which all moving parts are so to approach each other or; contracttoward lies within the chamber 12.

nationand arrangement of parts, all of which Qfwill be first fully described. in the following; detailed description, then be particularly.- pointed out in the appended claims, reference being had to the'accompanying drawing, in'

I Figure 1 is a vertical longitudinalsection illustrating my invention, the parts being in the. position they assume when the valve is seated; I Figure 2 is a similar view, the parts being in the position they assume when the cam '55, has raised the tappet'to open, the valve. i Figure. 3 Ba cross section onthe line 3'3i of Figure 1. I

Figure 4 is a cross section onthe line l4 f of Figure 1.1 Figure '5 is a perspective view of thesplit member. 7

- hithedimwingsa in which like numerals of i reference indicate likeparts in; all; of the figures, 1 represents thecam-shaft whose cam Qis designed to engage the base 5 of the tappet body 4,;the latter being cylindrical in; formand of tubu-larstructure and mounted I to slide in the bearing 3 of the engine. With-- in thetubn'larbody there is mounted a split member. consisting-of a base 8 from which projects upwardly a tubular portion 7 that is provided at'its upper outer portion with a cylindrical contactingor gripping face 9 panding or clutching face-111. Beneath the 'elutc-hingfacell the, splitzmember'ffhas a,

cylindricahchamber 12in-which a coil spring 16 isdisposed." j. y i; i The base-8 has a snug slidingfitwithin has a slight clearance fromthebodyf. "The member Zis made of such materialthatthe 5 with the clutch portiengl i-ofthe plunger member 13, the latter having a stem- 15 that" 10- designates thelongitudinal splits in the, member 7. I I;

The plunger member 13 is bored and tapped as atl? to receive theadjusting screw 18,

{whose head 19 contacts the end of the valve :95

stem 21, and whose threaded portion is provided with a jam nutQO as shown.

Th valve stem 21, spring holdin cap 23,retain ing clip 22, and spring 24 may all. be of a y "of e... i$ w nst i and" per se constitutes no part of the present invention.

Preferably I make the top of the head 19 of the adjusting screw 18 convex so as to facilitate the wiping action of the cam which tends to turn the tappet on its longitudinal axis in its bearing 3 to prevent undue wear.

In operation, when the engine is cold the adjusting screw 18 is so adjusted that the

surfaces

11 and 14; will be in contact without bringing the surface 9 into contactwith the internal surface of the member 4. The adjustment is also so made that the valve'stem 21 will be in contact with the head 19 of the adjusting screw. lVith the parts in this position, as the cam shaft rotates and forces the tappet upwardly the

cone clutch surfaces

11 and 13 will cause the split end of the member 7 to expand laterally, thereby bringing the surface 9 into tight contact with the inner wall of themember .4 and securely lock these parts together-during the upward thrust of thetappet.

On the downward stroke of the tappet the parts will remain in this position until the valve has seated which will occur just prior to the time when the base 5 has reached the limit of its downward movement. The slight additional movement (which was allowed for in valve clearance in the old practice) is taken up by the contraction of the split member 7 and the consequent forcing down of that member and the member 4 while'the plunger member is held up by the spring 16 into contact with the valve stem 21.

- By myarrangement it will also be seen that the oil accumulating from the bearing 3 will overflow into the member 4 and substantially fill it. In order to prevent stagnation of this oil a drain hole 6 may be provided in the base 5 throughrwhich the oil may gradually flow andalso assist in lubricating the line of contact between the cam 2 and the base 5. The'presence of the oil in the cylinder l also assists indamping any possible noise that might take place due to the slight clearance between the surface 9 and'the internal surface ofthe member 4.

Tests have shown that'a valve mechanism embodying my present invention can be run at exceedingly high speeds and all valve tapping noise eliminated.

' lVhile I have illustrated my invention specifically' as embodied in a tappet, it is obvious that it may also be embodied in the push rod-structure or in the connection between the rocker arm and the valve stem of an overhead valve type of engine. As such modifications of Y the invention would be mere changes in form and not in'substance, illustration thereof is thought to be unnecessary. From the foregoingdescription, taken in connection with the accompanying drawing,

itis thought theconstruction, operation and; F advantages of my' invention willbe clear to those skilled in the art to which it relates. What I claim is: 1. In valve operating mechanism, the combination with the tappet operating cam and the valve stem of an engine; an operating means located between said cam and stem and including a tubular body, a bearing in which said body has'a reciprocating sliding fit, said body having an opening in its top, a split tubular member fitted within said body and having a cone-clutch area within one end and a .body contacting area on its outer surface, a

plunger member having a clutch portion and a stem to fit within said split tubular member,

and a spring within said split tubular member.

member adaptedto contact the valve stem at all times.

3-. In valve operating mechanism, a valve tappet comprising a cylindrical body having a cam-engaging base. atone end'and being open at the other end, a valve stem contacting plunger memberincluding a cone-clutch vportion and a stem'portion to project into said cylindrical body, and means in said cylindric'al body embracingsaid plunger member for maintaining a continuous metal-tometal'connection between said cylindrical body and said plunger-member, said plunger member adapted'to contact the valve stem at all times, said last named'means comprising" a-split tubular, bodyiitted within said cylin- (ll'lQal body and having a cone-clutch face continuously tending to contact with said cone-clutch portion of said plunger member, said split body being forced into tight contact with the wall of said cylindrical body when pressure is applied tending to force said plunger member'into said split'body.

4. In valve operating mechanism, a valve tappet comprising a cylindrical bodyh'aving a cam-engagingbase at one end and being open at the otherend, a valve stem contacting plungermemberincluding a cone-clutch portionrand a stem portion to' project intosaid cylindrical body, and means in saidcylindrical body embracing said plunger member for maintaining a continuous metal-tometal connection between said cylindrical body and said plunger member, said" plunger member adapted to contact the valve stem at alltimes, said last named means comprising an internal cone seat and with an external e a split tubular body fitted within said cylin drical body and having a cone-clutch face continuously tending to contact with said" cone-clutch portion of said plunger member, said split body being forced into tight contact with the wall of said cylindrical body when pressure is applied tending to .force said plunger member into said split body, and means continuously tending to separate said plun er member from said split body.

5. In Valve operating mechanism, a valve tappet comprising a cylindrical body having a cam-engaging base at one end and being open at the other end, a valve stem contacting plunger member including a cone-clutch portion and .a stem portion to project into said cylindrical body, and means in saidcylindr cal body embracing said plunger member for maintaining a continuous metal-to-metal connection between said cylindrical body and said plunger member, said plunger member adapted to contact the valve stem at all times, said last named means comprising a split tubular body fitted within said cylindrical body and having a cone-clutch face continuously tending to contact with said cone-clutch portion of said'plunger member, said split body being forced into tight contact with the wall of said cylindrical body when pressure is applied tending to force said plunger member into 'said split body, and means continuously tending to separate said plunger member from said split body, said last named means comprising a spring within said split tubular body for engaging the stem portion of said plunger member.

6. A valve tappet for internal combustion engines,comprising a tubular body having a cam-engaging base at one end and being open at the other end, a member comprising abase portion fitted within said body and a longitudinal split tubular portion whose end remote from said base portion is provided with gripping surface, the latter being adapted to engage the, adJacent inner surface of said tubular body when said split portion iseX- panded, a plunger element for contacting with a valve stem andprojecting into said" split tubular portion and havingfa cone surface to engage with said cone seat for expanding said split tubular portion into engagement with the wall of said tubular body y when said plunger member is forced inwardly,and yieldable-means tending to force said plunger member outwardly.

JOHN NICHOLAS PERKIN V