US2982274A

US2982274A - Action mechanism for a poppet valve

Info

Publication number: US2982274A
Application number: US855742A
Authority: US
Inventors: George M Braun
Original assignee: Individual
Current assignee: Individual
Priority date: 1959-11-27
Filing date: 1959-11-27
Publication date: 1961-05-02
Anticipated expiration: 1978-05-02

Description

G. M. BRAUN May 2, 1961 ACTION MECHANISM FOR A POPPET VALVE 2 Sheets-Sheet 1 Filed Nov. 2'7, 1959 A MW m \m 3% W i &. w W7 a) w QN JNVENTOR.

GrEaBGE A7. BEAU/V BY m. mx zrm ATTOIQNE Y) 2 Sheets-Sheet .2

INVENTOR.

AI'ZOE/Vf j G. M. BRAUN May 2, 1961 ACTION MECHANISM FOR A POPPET VALVE Filed NOV. 27, 1959 'Eazas M EPQUA/ BY mechanism fora poppet valve.

More particularly stated, mylinvention relates to an Myinvention relates to an improvement in action improvement in .valve. action'mechanism not only pro-..

viding for improved control for quiet and efficient opening of a poppetvalve, but alsoproviding for ,resilient, but substantially positive closing action.

Furthermore, my invention makes special provision for resiliency and adjustmentof a valve action mechanism in a compact form adapted to be mounted in a chamber.

open at one side relative to the usualj location of a valve actionmechanis m',

In the drawings: o g 3:72.

Fig. 1 is ,a vertical sectional view showing fragrhentarily thatpor'tion of an internal combustion engine-including my valve ,action mechanism; the section being taken in,

aplane normal to the axis of the cam-shaft.

,{F ig Z is a section on line.2-.2 of Fig, 1 1

:,Fig. 3 isan exploded view of a rocker armeandfspring therefor in accordv with my invention.

fFig. 4 is a section on line 4-4 of Fig. 1.

showing an alternative form of my invention, 'Fig. 6 is a sectionon line 6 -6 of Fig.5; Fig. 7 is a section on line '7l,7 of Fig..5. .Fig, 8 isa sideelevation of a, rocker arm, in a second alternative form of my invention a. portion of the rocker ar'm being broken away tofeiihibit the construction through a verticalsectioni v Fig. 9 is asection on line 9- 9 of Fig. 5.

An environment for myinvention includes a cylinder block 15 fragmentarily shown in the drawings and a y r sfia fig qt iqa Qf C ed to P o-; vide ;-a firingphamber 17 int o which fuel mixtures may be'fe d or from which jexhaust gases may be released by a poppet valve 18 including a valve head 19 and valve 35 Fig. .5 is a view somewhat comparabletoFig. 1, but

- k States Pat fi V Patented May 2 ,1961

U The closing of the valve is accomplished by the and follower. Cam 33is provided with cam lobe 38 of such configuration as toproperly raise the cam follower 35 for the opening of valve 18 in timed relation for the operation of'the engine with which this valve action is concerned.

. It will" bcnoted that along the stem and with respect to the camfollower 36 there is no spring to close the valve and it will be' noted that in the cam and cam follower actionrespecting the cam lobe 38 on cam 33 there isonlyprovision for positive opening of the valve. valve action mechanism now to be described.

For the chamber there is a closure plate 40 to close the "opening at 4 1, and lying between plate 40 and thevalve stem 20 there. is a rocker arm shaft 42. This rocker arm. shaft provides a mounting for rocker arm 45, one end of which is bifurcated at 46 so that the two i portionsof it at 47 and 48 respectively may be disposed with the stem 20 therebetween. At the'otherend of the rocker arm there is an adjustably mounted resilient push-rod connection 50. This assembly includes a rocker spring Slassembled with the rocker arm 45 as shown in Figs. 1 and 3 where it will be seen that the rocker arm itself is effectively made unitarily including a spring backuparm 52 and a rocker hearing sleeve 53. The spring 51 in ;released position has contours shown in Fig. 3 to provide forready assembly with a somewhat cylindrical portion54 to. lie about sleeve 53. In the extended spring arms. 55 and 5,6, are apertures to receive'adjusting stem 57 of the push-rod connection 50. Stem 57 is threaded and is provided with nuts and lock nuts at 58 and 59 to provide foradiustment of spring 51 as will be described below'and it :will be noted that the lower end of stem 57 .is hemispherical so as to bear against the socketed end of valve closer, stem. 60. This valve closer stem with its valve clo er cam follower 61 is reciprocably mounted through the floor 31 of chamber 30 in such relation to cam shaft 30 that,-with roller 62 in position at the lower end of camfollower 61 there is an anti-friction relationship with valve opening cam lobe 65 forming part of the cam shaft 33. Ihiscam lobe has its position close to cam lobe 38 but-:slightlyaxiallyoff set therefrom and. it will beQnotcidthatthe rockerarm 45 isso shaped as to ofiset-the bifureated .end} 46 from the aligned cam-lobe 65 and the valveiclosmg stem 60,v (See Fig. 2.) A

Assuming that the parts thus far described are to vbe assembled in the first instance, stem 20 will be inserted Sigma 9-; bs a a vc pa ts. .9,. aud are gu d d; in t theirlimited reciprocal motion by valve guide 21 carried by a wall 22 forming part of the cylinder block. Above the wall 22.there isa chamber or passageway 23 for gases and at 24 there isa top. wall of this chamberor passageway which is provided with a port 25. to be opened and closed by reciprocation of valve 18.

Usual provisions for coolant in jacketed portions of the block 15 and of'the head 16 are shown at 28 and 29 respectively. a

Some of the important valve action mechanism to be described below ishoused in a chamber 30'lyingbeneath wall 22 and above fioor 31 of chamber 30.- .Below floor 31 is crank case 32, adjacent. the top of which extends cam shaft-33 for the operation of the valve mechanism. Floor 31 therefore provides amounting for a cam follower 35 fitted'for vertical reciprocation as shown clearly in Figs. 1 and 2.

The lower end of stem20 of valve 18 is threadedlyiengaged withcam follower Y35 and there is a lock nut 36 o with special lock'nut 37 to make it possible tov establish positive adjustment of the length of the combined stem through guide 21 priorto the time that the cylinderhead '16 "-is' appliedto cylinder block 15. Obviously, nuts and lock nuts; such. as 3.61and 37 arenot applied to the stern 20,.imt1 theivalye stem is approximately in position for threaded ehsiaszement with its cam follower 35. Prior to the time that the cam shaft --33 is assembled with the engine. cam follower 35 is inserted throughthe opening in the floor 31 provided therefor and it is thenpossible to threadly engage stem 20 with the cam follower. Later,

when the cam shaft 33 is assembled with the engine, adjustment of the stern and cam follower will be so made and locked thatthe valve will be in fully closed position when the cam follower 35 is approximately in bearing relation to theconcentric smallest diameter of the cam shaft 33 but allowing the usual clearance, for expansion.

Cam follower 61 is then placed in position asshown in Figs. 1' 'and 2, the rocker arm 45 is placed in position upon rocker arm shaft 42 and whenpush-rod stern 60 is placed in position in the cam followe'r 61 asj shown in Fig. l push-rod connection 50 is assembled upon the. rocker arm and in proper relationship to spring 51. The j proper relationship inflthis'regard is attained when the bifurcated end "46 'of" lever 45 is brought to bear upon- 7 valve closingwasher 67, which isj rigidly secured tostern This proper relationship, when valve. 18 is closed, is

determined by the proper of spring 51 against the nut and lock nut assembly 59 in position upon stem 57. With all the lost motion taken out of the relationship of the various parts, a firm degree of pressure must be exerted by' bifurcated arm 46: of rocker arm 45 when the roller 62 is on the concentric largest diameter of cam 65., ,This determines that the spring pressure is exerted to keep the 'valve head 19 firmly upon its seat in closed relationship to the'aperture 25. Then when the cams are rotated as will be described below, there is a cam valley at 66 in cam 65 in proper timed relationship to the position of cam lobe 38 to open and close the valve 18 as the cam shaft 33 rotates. V The alternative construction shown in Figs. 'to 9 inclusive is quite similar to that described above, except that the spring provided at 5l finds its functional equivalent in a spring 75 in the form of a helical cylindrical spring disposed between a cam follower shelf 76 on cam follower insert 77 carried by cam, follower 35. Then at 78 there is a floating washer apertured to receive stem 20 of valve 18 so that the floating washer may reciprocate upon the stem under the control of the bifurcated end 46 of rocker arm 80. This rocker arm 80 is substantially rigid since the features of resiliencydesired for valve closing operations are provided by spring 75.

This means that a push-rod assembly 85 merely requires a threaded adjustment without any direct spring accommodation relative to the rocker arm at that point. It

will be noted as shown in Figs. 5 and 6 that a cam shaft 90 is provided with two cams relativeto each valve.

Cam 91 has a continuous concentric lobe except for the relieved valley at 92. Whereas cam 93 has a relatively short lobe 94 and a continuous concentric valley 95 extending around the rest of the circumference. The relationship of the two 'carns is shown most' clearly in Fig. 5 where it will be seen that in view of the'number of degrees by which the valve stem 20 is offset from the push-rod stem 60 of the valley at 92 provides a degree of relief when the lobe 94 opens the valve, but when the valve is to be closed the lobe 94 has passed the cam follower 35 to permit of the valve closure and the pushrod 60 has been thrust upwardly to the left as seen in Fig. 5 whereby to bring rocker arm pressure on spring 7 5 to urge the valve to closed position. t

To provide shock resistance for rocker arm 80 the rocker arm may be provided as shown in Fig. 8 in an.

spring pressure of the end 56 or open said opening, a'valve action chamber positioned adjacent the chamber for gases with a wall therebetween including a guide for the stem of the valve extended across the valve action chamber; a walled crank case, one wall of which is positioned to provide a floor for said valve action chamber equipped with divergent guides for cam followers; cam followers in said guides; a cam W equipped cam shaft positioned in the crank case adjacent said cam followers, a valve action lever and shaft therefor in the valve action chamber adjacent said stem, and action transmitting connection respectively including said cam followers between the cam equipped cam shaft and the stem, and between said cam substantially positively opening said valve.

said cover. j

5; A valve action mechanism for a stemmed poppet 3. The engine of claim 1 in which'the stem is provided with a spaced apart fixed shelf and floating washer with a compression spring therebetween, and the lever is positioned to bear upon the washer in a direction to compress the spring in a valve closing direction.

4. The engine of claim l in which the valve action chamberis provided with an openable inspection cover andthe connections between the lever and the cam shaft are adjustable and valve provided with a valve action shelf fixedly mounted to the stem of the valve, cam means oppositethe end of the stem in position to bear thereupon in a valve opening direction, cam follower means positioned to be actuated by said cam means in an angular direction divergent from said stern, a lever mounted to a lever shaft positioned within the angle; one end of the lever extending into position against the shelf and the other end of the lever having a connection with the divergent cam follower means; one of said ends of said lever comprising a' rigid spring back-up arm and two spaced spring arms with a wrap-around spring intermediate portion integral with said spring arms, said wrap-around portion being positioned about said lever shaft.

. 6. The valve action mechanism of claim 5 in which a sleeve is positioned between the lever shaft and said wrap-around spring intermediate portion.

References Cited in the fileof this patent UNITED STATES PATENTS Italy Dec. 22, 1956 positioned within service distance of