US2118450A - Internal combustion engine - Google Patents

Description

May 24, 1938. v ZAHODIAKlN 2,118,450

INTERNAL COMBUSTION ENGINE Filed June 25, 1935 N 6 @52 1 INVENTOR I I v J ./2 y- 1 9 W I Wndr Wwi ATTORNEYS.

Patented May 24, 1938 GEE-[ICE Ap lication alnne'u25,

'; 2"Claims.

zThisair-ivention relates tozint'ernal combustion :en'gines-and issparticularlyidirectedzlto :improvenmentsirr'ithe mechanism fonactua-ting theualyes .lthereof. iezBecause sof ;1 the.: :faet thatttheizmetal :parts. expand :when heated-m the normalaopera- 'tion of the-engine itrhas' beenz necessarytstoz-provide working clearance between i the walvesand -the valve- :actuating -mechanis1mto accommodate 'forthisexpansion. Naturally; when -ither-clearv. ance -"has -not beenntaken up by expansion, :s-as

- when the motor- =is cold =or not heated: to-the normal operating itemperature, it at great "dealof vibratiomand impactycausing noiseand damage to the 1 parts.

It -is therefore an obj eatof this invention toprovide an 1 improved, simple, and eflicient d'evioe incorporated 4 in t a valve actuating mechanism which" provides for --an= ample: amount ofl lostor idle-motion-for permitting expansion=-oi; the parts, 1,20 which lost. or idle -motion'-'is afforded lieu" of the "usual clearance whichrnw on ly= permitsexpansion, but automatically maintains constant contact between the parts of theivalve actuating mechanism whereby there-=-is r-no impact or" con- 4 cussion suchas would occur-if com'pleteclearance between the parts-were taken up. E

-=It isa, further object'of'this invention to' provide an improved device m the-valve=operating --'-mechanism, which device permits expansion of ;,-..30' the parts and results'in operation. of tlu-z val-ves Without noise, vibration; Qr-impacraand without excessive -=wear or breakage of the -contacting elements. It is astill further'object of this-"invention-to provide a device ior this purpose-which is -more easily "manufactured, morepositive; moredura- -ble;-more accessible, and-easier""to install in the valve-operating mechanism, also the invention in one'phase;=simply-requires replacement "of the cam follower normally used for-a *special cam follower incorporated in the improved device: and -adds no additional;-reciprocating -weight to the "mechanism.

I It is a still further"- object of this invention" to 45 provide adevice' of "this character: quickly incorporated in'the operating'meohanism of--the--va1ve, which will permit operation of the en'gine 'valves in the event of failureor bre'alnage of the 'device. It is also provided that by an adjustment-in the "50* event that the contact parts become: worn,-o'ther available contact parts can bebrought into 'zop- -erative position for replacement -purposes.

' '-It is" a; still further object of thednvention to provide a. device of this character which isiefiee- 2:55 "tivefortaking up: the'elearanceby sliding'or roll- 193.5,; Seriah-N 0. 28325 iiing 'operationy thereby entirely eliminating imepactuand the usual-springing or disalignment of the parts} theelatter being an-advantage particu ularlytwhenithe. deviceisincorporated in the overuhead type oflengine yalveemploying a relatively 5 l;long1 push=rod.

lnther objects and certain advantages will be :more' fully apparent from the detaileddescription of the -drawing'pin which:

FF-figure l is a longitudinalsectional view-with 10 certain of theparts shown in elevation, this view showing'the complete device incorporated in the :r'operating -mechanism;

-Figlrre 2 isms-side view of the adjusting screw incorporated imthe' device ofFigure 1;

Figure 3 is a'plan view-of thelock-nutused for locking the adjusting screw'ofthedevice shown :-in Figure 1;

Flgure leis-a side-elevation-of the upper cam element or take-up element inwhichthe adjusteable con-taict screw ismounted;

Figure5-is a bottom view'of the ure 4;

Figure 6 'is-aviewof'one of the contact studs bff'the element shown in Figure 4;

Figure'iis a sideview of the-mainbody of the --cam'-follower incorporating the cam surfaces: co-

operating with the'upper; cam element;

FigureB is" atop plan viewof the element of Figur-V;

"Figure 9-is a'top plan View of the tension spring ==incorporated-in the-device of Figure 1' between the cam elementand the cam follower body;

Figure 10 is 'alongitudinal sectionalview of v a "cam follower-incorporating a'modified form of the' device "of this'invention;

Figure 11-is abottom 'view of thepush-rod incorporated 'in the device 'of' Figure 10;

Figure 12 is a side elevation partly in section of 'a"modified" form of"'device"incorporated in the "cam follower: 'of the'valve operating mechanism;

."Figure 13 is a bottom view-of the upper cam or wdgefelement. of. the device of Figure 12; and

"Eigurela ista top plan viewof the body portion .of the-camiollower.

Referring-to. Figures 1 to 9 'of the drawing, par- -ticularly:1 ;igure 1;. a portion: ofthe engine block --is:indicated; at- I 5. i-The-p'ortion .shown includes. a walveiv-seat and incorporatesr a valve guide element.- -(lfirrin whicha a'- va'lve. 7; is slidably mounted for -operation in relationto the-seat l8. Avalve incorporated in the :L head type of-engine is illustrated in' this case. "The'valve has an abutment means l9 'fixed -on'itslower end arid'a spring is sz element of Figsplit ring elements holding them in place in the annular groove, whereby they in turn prevent downward displacement of the abutment plate or disc.

The cam shaft is shown at 24. One of the cams 25 thereof is shown in Figure l, in operative con-. tact with the cam follower unit 26. This cam follower unit incorporates the take-up device of this invention. The follower unit is slidably mounted in axial alignment with the wave stem within a guide bore Zi of the engine body.

The main or body element 28 of the cam follower unit (see the detail views Figures '7 and 8) has a flared lower end in operative contact with the cam and is in the form of a thimble. The take-up element or upper cam follower element 29 is slidably and rotatably mounted within the bore of the cam follower. This take-up element is in the form of a sleeve including an integral nut or hexagonal head 38 at its upper end. An annular groove 3! is formed externally of the element just below the headed upper end to provide' clearance for a wound spring 32 exerting rotative force on the take-up element as will be hereinafter described.

It will be seen that when the take-up element is telescoped in the cam follower body, a chamber is provided by the association of the annular groove with the bore of the body. The take-up element is internally screw-threaded and an adjustable contact screw 33 is entered thereinto, the upper contact or headed end of the screw being in contact with the lower end of the valve stem at all times (see Figure 1). A look nut 3:2 maintains the adjusting screw 33 in position relative to the take-up element 29.

The coil spring has one terminal anchored in a radial slot 35 in the cam follower element and the other terminal anchored in a radial aperture in the take-up element toward the lower end of the annular groove and indicated at 35 The spring is wound under considerabletension to maintain a constant rotative force on the takeup element. This rotative force is converted into longitudinal or axial movement of the take-up element by a cam arrangement hereinafter disclosed.

Pins 36 having rounded lower ends are projected downwardly from the headed upper end of the take-up element surrounding the sleeve portion thereof. There are four of these pins spaced 90 apart. The upper edge of the cam follower body incorporates arcuate grooves 3'! which may be generally described as having diametrically related centers. Therefore respective diametrically related pins cooperate with these arcuate grooves. The result of the rotative movement constantly imparted to the take-up element is to urge the take-up element outwardly axially due to the fact that the pins ride up the curved surfaces of the arcuate grooves.

The other pair of pins not in use or in direct contact with the cam follower element are disshow the valve.

posed in diametrically cut slots 38 in the upper edge of the cam follower element. These slots present perpendicular end walls and afford positive abutments for engagement by the respective pins not in use for carnming purposes.

At this point it will be recognized that in the event the pins which are actually in contact with the arcuate surfaces become worn, the take-up element can be rotated 90 to place the other pins in service for direct contact. In this event the previously used pins can then function as the abutment pins since wearing of the contact or rounded ends thereof will not interfere with this latter function.

Now in the operation of adjusting the actuating mechanism so that appropriate lost motion or idle movement is afforded, the take-up element is rotated against the tension of the spring so that the pins rest at the bottoms of the arcuate grooves. A gauge is then placed between the contact screw 33 and the bottom. of the valve stem, and the contact screw is adjusted to the proper spacing. Uponrelease of the take-up element the spring will rotate and cam the same so that this clearance is taken up and positive contact o between the cam follower unit and the valve smm-is maintained.

When the motor is cold the condition shown in the Figure 1 of the drawing will exist, that is to say, the pins will be high up on the arcuate sur-e faces. As the cam actuates the cam follower unit, the lost motion will be taken up with the pins moving to the bottom of the grooves for a cushioned operating contact. It will be seen that there can be no impact because these pinsare i-g moving down a curved surface and no sudden abutment across a space occurs to cause impact or concussion. As the motor heats up and the parts expand, the take-up element will be rotated against the tension of the spring by an axial force resulting from functioning of the parts axially moving down the curved surfaces as this progresses.

Now the spacing selected for the possible idle or lost motion is great enough to take care of any expansion of parts, even under abnormal conditions, so that the valves cannot stay open and permit premature escape of gases.

The view (Figure 1) shows the position of the elements of the unit when the cam is not acting to unseat the valve.

In the modification shown in Figures and 11, a modified device operating on a somewhat similar principle is disclosed. In this case the improvements are applied to the overhead type of;

valve and for this reason the cam follower unit is shown in relation to apush-rod fit operating a rocker arm M. It is not believed necessary to A cam 42 engages the undersideof thecam follower element A3 as in the usual 7 practice.

Thecam follower unit in this. case as in the preceding form consists of two major parts, that is, a cam follower body i t of thimble form. The

take-up element 45 is also of sleeve form and is 1 nested or telescopically mounted in the cam follower body.

- The solid or closed lowerend of the take-up element presents an arcuate or curved upper surface Mi. The push-rod 40 includes a ball pertion 4123 near its lower end contained within the take-up element and centering the push-rod relative thereto by virtue of a snug fit in the takeup element. An elongated diametrically disposed rib l j ztms an e ten on om h b o ion.

of the push-rod. The lower or cross edge 49 of this rib is rounded, but the rib itself is straight lengthwise along the lower edge and is disposed crosswise of the curved bottom of the take-up element when in valve operating contact or working position.

A winding spring 50 is coiled about the pushrod, having one of its terminals anchored in a radial aperture 5% of the push-rod, and its other terminal anchored in an aperture 52. in the upper edge of the take-up element. The push-rod therefore is under rotative pressure at all timesso that when there is no working pressure axially of the cam follower and push-rod, rotative move' ment of the push-rod takes place. This rotates the rib 48 relative to the arcuate surface. Thus the push-rod is elevated and the contact between the upper end of the push-rod and the rocker arm is constantly maintained.

Upon each valve operating movement the pressure applied longitudinally of the elements causes a camming action to ensue between the pushrod and the take-up element rotating these elements relatively until the rib reaches the bottom of the arcuate surface to a position directly parallel therewith.

Another modified form of the invention is shown in Figures 12 to 14. The cam follower unit shown in the views illustrating this form is placed in the mechanism in the same manner as the unit of Figure l. The general elements of the unit are the same as in the preceding form, that is to say, a main cam follower body 6:") and a take-up element 6| are related in the same manner. A winding coil spring 62 is disposed in an annular recess 62* in the take-up element 6! in the same manner as in the preceding form for imparting rotative movement to the take-up element.

As shown, the take-up element incorporates an adjustable contact screw 63 as shown in the first form. A sleeve 64 is rigidly secured in an annular external groove 65 at the upper end of the cam follower body, this sleeve extending above the upper end of the cam follower body.

Motion limiting grooves 66 providing perpendicular abutment shoulders 61 are formed in the upper edge of the sleeve element and are diametrically related' as to centers. A cam collar or ring 68 is disposed around the take-up element and in assembled position is disposed within the sleeve immediately above the upper edge 69 of the cam follower body. This ring or collar is secured in position by radially disposed pins 10 which project beyond the ring into the limiting grooves or slots. The pins provide the rotative abutment elements co-acting with the shoulders 61 for limiting rotative movement of the take-up element under the action of the spring.

Diametrically opposite portions of the upper edge of the cam follower element, as well as the adjacent portions of the lower edge of the ring, are-provided with shallow grooves H providing arcuate cam surfaces or tracks. Balls 12 are inserted between and in contact with the adjacent grooves of the respective parts.

It will be apparent that the rotative forces of the spring will tend to spread the parts, that is to say, elongate the cam follower unit, maintaining the contact with the cam and with the lower end of the valve stem or the valve operating mechanism as the case may be. However, a limited amount of idle or free motion can occur, permitting expansion of the parts before solid operating contact occurs. When the balls are located at the bottoms of the respective grooves, or the parts have been moved together until further motion is obstructed by the balls, positive driving contact occurs. It will be seen that this occurs without concussion or impact since the balls move on curved surfaces and the lost motion is taken up gradually as opposed to impact,

as when the parts move across a clearance.

These devices entirely eliminate clearance and at the same time afford positive operating contact.

Having described my invention, I claim:

1. In a valve operating mechanism including a spring seated valve and a cam therefor, a cam follower unit in constant contact with thevalve and cam, said unit incorporating telescopically related elements, one in contact with the cam and the other in contact with the valve, a winding spring for urging said parts rotatively relative to each other, a cam surface and a groove having vertical end walls formed on the end of one of said elements, pins projected from an adjacent surface of the other element, one of said pins riding on said cam surface and the other engaged in said groove, said elements moved apart under the influence of the spring through the cam surface contact, said second pin limiting rotative motion by engagement with the vertical end walls of the groove, and said pins interchangeable as to the groove by'rotative adjustment of the elements.

2. A device of the class described including a cam operated valve operating mechanism, comprising, an external shell forming the cam follower and having a closed end in engagement with the cam, a cylindrical element axially slidably and rotatably mounted in said shell and including a head overhanging the upper edge of the external shell, said external shell and said head of said cylindrical element including cam surfaces cooperating for causing relative axial movement upon relative rotation thereof, said shell and cylindrical element providing an annular chamber therebetween, said chamber located immediately adjacent the plane of the cam surfaces, a coil spring disposed within said chamber and having its ends respectively attached to the external shell and the cylindrical element for urging said shell and cylindrical element rotatively in relation to each other, and an adjustable contact screw in said cylindrical element having its head extended axially outwardly therefrom.

VICTOR F. ZAHODIAKIN.

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