US2378726A - Poppet valve-actuating mechanism - Google Patents

Description

Patented June 19, 1945 1 K 51 refiner tnveimimememen I Galen H. Peters, Los Angelcs, Calif.

Application Mama, 1944,,seriainuaeamrs rciain. (01.,133 -90) This invention :relates to; poppet valve-actuat ing mechanismgand more particularly to improvements; in the cam constructionfor actuating the ipoppet' valves of an internaf'combustion engine. i C'I-hergeneral object of the invention is to providean' improved cam construction which makes it -:unnecessary to overcome {spring tension-in opening the poppet valves of an internal combustioniengine. I 1 l .kA more particular object is ito providef an improved: cam 'iconstructionof the character stated for-rpositively:=opening and-c1osirig the poppet valyesr ofa n internal combustion engine. cAnother. object is to provide a cam. construction-:for'actuating the vpoppet; valves of an intern'el combustion engine Joy means of which said valvesare put under spring tension by the actuating cams. at their lowermost position for holding' :said valves closed firmly upon their seats.

tionwof anintemal combustion engine,showing I one-.1015 the: poppet valves of the] engine and my improved cam construction for actuatingsaid' valve',whichiss'hownclosed.

is a fragmentary longitudinal-vertical I sectionoftheinternal combustion engine shownon ;F?ig.:1; showing two ofthe poppet valves-pf the .engine and my improved 'camconstruction foriaetuating'thesame, one of-said valves being shown-:closed and the other valvebein'g shown open, 1

crEig. f3 isi'a sectional view of "my improved cam construction for actuating the poppet valves shownz-invli'ig. 1 and taken on line 3- 3 thereof;

vFig is a "fragmentary elevation of the; stem Qfzthewlosed :valve shown in Figs. 1 and '2, the

tappetxzfor .actuating'asaid -valve,' and the spring qf;,-.=mycam construction. connecting said valve stemr and said-tappet, :the tappet being. drawn downrislightly .belowthe valve stem 'bymy cam construction, further expanding 5 :said; spring whereby said valve is held firmly closed: upon:- its Arunther object is to provide a cam construc- Fig. 5 is a fragmentary elevation of the stem of the open valveshown in Fig. 2, the tappet lifting'said valve, and the spring of my cam con st-ru'ction connecting said-valve stem and said tappet, the tappet being raised-bysaid cam construction-and said spring being contracted slight- 1y; whereby the upper end 'of's aid; tappet engages the lower end of said valve stem :and raises and openssaid valve.- i a 11 Fig. dis a horizontal cross section of the s'tem of 'the-closed-val-ve shown in Figs. 1 and 2- taken on line 6'--6' of Fig. 4 and: showing the connection of .the upper end-of the spring Of my' cam con-' struction to said valve stem. a

Fig. '7'i's a horizontal cross section- 0f the tappet of the open valve shown-in Fig. '2, takenon line L- l'of Fig; 5 and showing the connection'of the lower end of the sprin of my cam construction tosaidtappe't. w i Referring more particularly to the drawingyin which corresponding parts are designated by the same reference characters i-n'all of the -figures,l designates a poppet valve of an internal combustion engine 2, and designates mynovel' came actuating mechanis'm'for said poppet valve, which mechanism is. suitably mounted on said: engine. The poppet-valve! comprises a valve head 4 and-a valve stem 5 depending'from said head and slidably mounted ina valve-guide bushing-=6, so that said valve headmay bemoved downupon its seat 1 to-cl'ose the-valve, or'lifted above its seat to open the Valve, in the manner hereinafter more fully described. "The poppet valve l controls communication between afuel inlet or-exhaust port8 and acombustion chamber!) of-an internal combustion engine 2. I

.My'cam-actuating mechanism '3 includes a conventional-valve-openingcam I0 and a pair "of valve-closing cams II, a yoke 'l2fitted over'and engaged 'by 'said cams,- a plunger I3, turnably 0011- ne'cted atits lower end to said yoke and extend ing upwardly therefrom,'a tappet 1'4 adjustably. connected to-said plunger and extending upwardly therefrom,-and a-coil spring -l5 surroundingthe upper portion of said tappet M and the lower'po'rtion of thevalve stem 5 which sprin is expanded to'a predetermined tension, and is connectedat 'itsends to said tappetand saidvalve stem, respectively, in the manner hereinafter moreuparticularly described. The cams l0 and H are secured on the conventional cam shaft I'B ofthe engine 2, with the cams I'l suitablyspaced, apa t and, thecam 1:0. positioned midway between saidsxcams :lt. .;.'Ih.e yoke 12 comprises a .pairof guide rails .1515; and: apair 10f; cross-bars I:8.:a-nd;1-18.

The cross bar I8 is adjustably secured at its ends on the lower ends of said guide rods II, respectively, by nuts 20 and .2I threaded on said rods, and the cross bar I9 is adjustably secured at its ends on said guide rods, respectively, above the cross bar I8 by nuts 22 and 23 threaded on said rods, with the cross bar I8 adjacent the lower edges of the cams III and I I, and the upper cross bar I9 adjacent the upper edge of the cam Ill. The guide rods II extend upwardly above the cross bar I9 and the upper portions of said rods are slidably fitted in guide bearings 24 depending from a horizontal wall 25 of the engine 2, whereby the yoke I2 is mounted to be reciprocated up and down by the cams I and II for opening and-closing the poppet valve I, in the manner hereinafter more fully described; The cross bar I9 is provided with an opening 26 therein midway between its ends, through which open ing extends the lower end of the tappet plunger I3, which end of said plunger rests upon the upper edge of the cam I0 and is formed with an external annular flange 21, which is countersunk in the lower surface of said cross bar I9 in an annular enlargement 28 of the lower end of said opening 26 in said cross bar, which enlargement forms an annular shoulder 29, in said cross bar, engaged by the upper surface of said annular flange 21 of said plunger I3, in the'manner and for the purpose hereinafter more fully described, said plunger I3 and its said flange 21 being tumably. fitted in the opening 26 and its enlargement 28, respectively, in the cross bar I9, so that the poppet valve I may turn at all times. The tappet plunger I3 extends upwardly from the cross bar I9 of the yoke I2 through a guide bearing 30 depending from the wall 25 of the engine 2, and is formed with a threaded bore 3| in its upper end portion, in which bore is threaded the lower threaded end portion 32 of the tappet I4, the upper end 33, of which tappet extends adjacent the lower end 34 of the valve stem 5. On the tappet I4, intermediate its ends, is formed a hexagonal surface 35 to be gripped by a wrench for turning the tappet in threaded engagement with the threaded bore 3I of the plunger I3, whereby the tappet is adjusted longitudinally up or down with relation to said plunger to increase or decrease its length above the upper end of saidplunger. A lock nut 36 is threaded on the tappet I4below the hexagonal surface 35 for engaging the upper end of the plunger I3 for locking the tappet I4 in longitudinally adjusted positions with relation to said plunger. The coil spring I5, surrounding the upper portion of the tappet I4 and the lower 4 portion of the valve stem 5, is detachably connected to said tappet and said valve stem by clamps 31 and 38, respectively, on the lower end and upper end of said spring. The clamp 3! comprises a yoke 39 and a screw bolt 40 and nut M, which yoke is formed by the lower end of the spring I bent U-shape transversely of the spring and in the form of eyes 42 and 43 at the ends, respectively, of said yoke, throughwhich eyes ex-, tend said bolt 40, with the head 44 of said bolt engaging said eye 42 and said nut 4I threaded on the end of said bolt, engaging said eye 43. The

yoke 39 straddles the tappet I4 and is fitted in an annular groove 45 in the periphery of said tappet, with the ends of said yoke projecting transversely beyond the side of said tappet, opposite its side which i engaged by the intermediate portion of said yoke in said groove 45 and with the screw bolt 40 extending tangentially through said groove 45 between the ends of the yoke. The clamp 38 comprises a yoke 46 and a screw bolt 41 and nut 48 which yoke is formed by the upper end of the spring I5 bent U-shape transversely of the spring, and in the form of eyes 49 and 50 at the ends respectively, of said yoke through which eyes extends said screw bolt 41 with the head SI of said bolt engaging said eye 49 and said nut 48 threaded on the end of said bolt, engaging said eye 50. The yoke 46 straddles the valve stem 5, and is fitted in an annular groove 52 in the periphery of said valve stem, with the ends of said yoke projecting transversely beyond the side of said valve stem opposite its side, which is engaged by the intermediate portion of said yoke in said groove 52 and with the screw bolt 41 extending tangentially through said groove 52 between the ends of said yoke.

The operation of my invention is as follows:

Assuming the poppet valve I to be closed and my cam-actuating mechanism 3 to be in its lowermost position, as shown in Fig. 1, and as shown by the valve I and my actuating mechanism 3 at the left of Fig. 2 of the drawing; rotation of the cam shaft I6 and the cams I0 and II upon operation of the engine 2, causes the high point 53 of the cam ID to engage the lower end of the plunger I3 and lift said plunger and the tappet I 4 sufficiently to cause the upper end of said tappet to engage the lower end of the valve stem 5 and lift the valve I until the valve head 4 is lifted off its seat I and the valve is opened, during which operation the upper surface of the annular flange 21, on the lower end of the plunger I3, engages the annular shoulder 29 in the cross bar I9 of the yoke I2 and lifts said yoke to its uppermost position while the low points 54 of the cams II are brought to their lowermost position above the cross bar I8 of said yoke to permit said yoke to be lifted as aforesaid, and as illustrated by the valve I and my valve-actuating mechanism 3 at the right of Fig. 2 of the drawing. As the cams I0 and II are further rotated the high point 53 of the cam II] is rotated away from the lower end of the plunger I3, and the low point 55 of said cam is brought under said end of said plunger, while the low points 54 of the cams II are rotated away from the lower cross bar I9 of the yoke I2 and the higher points of said cams II are rotated against said cross bar I8, whereupon the yoke I2 is drawn downwardly and the shoulder 29 in the cross bar I9 of said yoke, engaging the upper surface of the annular flange 21 on the lower end of the plunger I3, causes said plunger-and tappet I4, spring I5 and the valve stem 5 and head 4 to be drawn down positively by the cams II until said valve head 4 engages its seat I, and as the highest points 56 of said cams I I directly engage the yoke cross bar IS the yoke I2, the plunger I3 and tappet I4 are drawn further downwardly a slight distance against the tension of the spring I5 until the upper end of said tappet is drawn down a slight predetermined distance below the lower end of the valve stem 5, whereupon the spring I5 is expanded slightly and a downward force, under the tension of said spring is applied to the valve stem 5 and head 4, and said valve head is drawn down with greater force against its seat I, and the valve I is more firmly and effectively seated and closed, as shown in Fig. 1 and as illustrated by the valve I and my cam-actuating mechanism 3 at the left'of Fig, 2

of the drawing. V

Iclaim:

In combination with a poppet valve and the- 2,378,726 3 cam shaft of an internal combustion engine, a

valve-opening cam and a valve-closing cam on said cam shaft, a plunger and a tappet connected to the upper end of said plunger arranged with the lowerend of said plunger resting upon said valve-opening cam and the upper end of said tappet extending adjacent the lower end of the stem of said poppet valve, a reciprocative yokev including a lower cross bar, engaged by said valve-closing cam, and an upper cross bar to 10 which the lower end of said plunger is turnably connected, and a coil spring surrounding the upper end portion or said tappet and the lower end portion 01 the stem of said poppet valve and connected at its lower end to said tappet and at its upper end to said valve stem, with said spring expanded for holding the upper end of said tappet against the lower end of said valve stem, and said valve-closing cam being arranged to engage said lower cross bar, when said poppet valve is upon its seat, for drawing down said yoke and said tappet a slight distance against the tension of said spring, for seating said valve firmly upon its seat under tension of said spring.

GALEN H. PETERS.

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