US2206869A - Valve actuating mechanism - Google Patents

Description

o. Hf BANKER VALVE ACTUATING MECHANISM Filed'auly 24, 195s Patented July 9, 1940 STATES PATENT orma 7 Claims.

The 'invention relates generally to a valve actuating mechanism for an internal combustion engine and more particularly to the valve lifter of the actuating mechanism.

A general object of the inventionl is to provide a valve actuating mechanism of new and improved construction rendering the mechanism extremely quiet under all operating conditions, economical to manufacture, efficient, durable, and

easy to install either initially or as a replacement for no isy, worn or obsolete mechanism.

A more particular object is to provide a valve actuating mechanism of new and improved construction in which metal to metal contact blows are eliminated, thereby avoiding the noise and .the periodic vibration incident to such blows.

Another object is to provide a valve actuating mechanism having a two part valve lifter, one part being maintained in constantengagement V2O withrthe valve stem and the other part being maintained in constant engagement with the valve actuating cam and the parts having a new4 and improved cushioned engagement of large area, assuring long life of the cushioning material and ready separation of the engagement so that the parts will be maintained respectively in engagement with the valve stem and the cam.

Other objects and advantages will become ap- .parent from the following detailed description taken in connection with the accompanying drawing, in which:

Fig. 1 is a view, partially in section, of a valve actuating mechanism for an internal combustion engine embodying the features of the invention.

Fig. 2 is a diametrical section of the valve actuating mechanism shown in Fig. 1.

Fig. 3 is a diametrical sectional view of a modified form of the valve lifter of the valve actuating mechanism.

Fig. 4 is a fragmentary diametrical sectional view of still another modified form of valve lifter. While the invention is disclosed in the drawing and will hereinafter be described as embodied in three forms or modifications, it is not intended that the invention be limited to the specific embodiments disclosed, but it is intended to cover all modifications and alternative constructions falling Within the spirit and scope of the invention as defined by the appended claims.

-Referrlng to the drawing, particularly Fig.l l, I0 represents the cylinder block of an internal combustion engine and I I represents a valve having a valve head I2 controlling a port opening into a cylinder ofthe engine. The valve is (Cl. 12S-90) mounted in the usual manner with its stem I3 projecting slidably through a sleeve bushing Ill secured in the cylinder block I0. At the` end remote from the valve head, the valve stem carries a washer. I5 between which and the cylinder block 5 I0 a compression spring l6'is interposed to urge the valve toward seated position. The valve is opened against the action of the spring I6 at proper intervals by means of a cam Il formed on a cam shaft I8 and acting through a valve 10 lifter generally designated I9. The valve lifter is guided for longitudinal reciprocatory movement in a bore 20 formed in a portion of the cylinder block Ill.

Herein the valve lifter is of unique construc- 15 tion designed to silence the operation of the valve mechanism. Generally, the valve lifter comprises afirst part generally designated 2| maintained in contact with the cam shaft I8, a second part generally designated 22 maintained in 20' Contact with the-valve stem and a cushioning means interposed between the parts so as to avoid metal to metal impact blows during the operationof the engine. The parts have a joint movementto unseat the valve and a slight move- 25 ment relative to one another in order at all times to .maintain the parts in contact with the cam shaft and the valve stem respectively and to provide the clearance necessary to take care' of expansion of the valve mechanism caused by 30 changes in engine temperature.

In the form of the .valve lifter shown in Fig. 2 the first or cam mechanism operated part 2| comprises a cylindrical main body portion 25 having a longitudinal bore 26 opening through the end remote from the camshaft I8 and a reduced neck 2'I at the same end. Mounted on the neck end of the mainbody portion 25 is a Icupshaped member 28 having a hub portion 29 tting over the neck 21 and by means of which the 40 cup-shaped member is secured'by a press fit to the main body portion 25. Disposed within the cup-shaped member 28 is a metallic washer 3U welded thereto as indicated at 3l and having a central aperture coinciding with the bore 26 of 45 the main body portion. For a purpose which will become apparent hereinafter, the cup-shaped member 2B is of substantial diameter, larger even than the diameter of the main body portion 25 land several times larger than the diameter of 50 f the valve stem I3.

The second or valve mechanism operating part 22 of the valve lifter ,consists of a disk-like cap 34 having a cylindrical guide portion or plung r 33 sliclabley in the bore 26.v The cap 34 is pre 5c erably slightly less in diameter than the inner diameter of the cup-shaped member 28, and has a boss 35 extending axially therefrom for engagement with the valve stem. At the inner end the plunger is reduced at 38 to provide a seat for one end a compression spring 3l dis-v 'maintains the main vvbody portion or cam shaft part in contact with the cam shaft |8 and the cap or valve stem part in contact with the valve stem i3. Spring 3l, of course, is weaker than spring I6.

Interposed between the parts 22 and 2| and herein in effect forming a portion of the cam operated part 2| is a cushioning means of nonmetallic material mounted in the member 28 and arranged to engage the cap 34 and thereby limit the approaching movement of the parts 2| and 22. This cushioning means takes the form of an annular washer 38 of a composition which is resilient and slightly yieldable but substantially incompressible volumetrically so that in order to yield in one direction or be compressed in part it must have space to expand in another direction or in another part. The resilient qualities are similar to those of rubber, but preferably the composition also does not deteriorate when exposed to heat and oil, a suitable composition being the commercial product known as Duprene, which is a product made from coal having some of the'characteristics of rubber.

As illustrated in Fig. 2 the washer 38 fits snugly in the cup-shaped member 28 so that it cannot expand radially, and the adjacent sides of the cap 34 and the washer 38 are formed so as to provide space into which a portion of the composition of the washer may expand when another portion of it is compressed longitudinally. Preferably, one of the parts is beveled or otherwise formed relatively to the other so that there will be a gradually increasing area of contact between the parts as the valve lifter is actuated to unseat the valve. Herein the cap 34 is beveled and the adjacent surface ofthe washer 38 is at. Such gradually increasing contact results from the relative movement of the parts 2| and 22 from the upward distortion of the Outer portion of the washer 38 under such movement. This assures that the engagement of the parts will be gradual and not a sudden impact,

and nevertheless the extent of the movement of the parts toward each other is limited definitely by the space into which a portion of the washer may expand.v Moreover, the large contact area of the washer 38 (it being many times that of the valve stem I3), assures that the pressure per unit area is low enough so that the washer will have a long life. 'Ihe beveled underneath surface of the cap alsoassures thatthe cap and the washer 38 Iwill again separate as the valve is returned to seated position and will not be held together by any suction-cup action.

Positioned between the annular washer 38 and the bottom of the cup-shaped member 28 are a plurality of shims 39 which preferably are of different thickness so that by the employment of different combinations the desired clearance i'n the valve mechanism may be obtained. This clearance is of an orderl of a few thousandths of an inch when the engine is cold resulting in a slight space between the cap 34 and washer 38 as shown in Fig. 2. As the engine warms up, however, this space may disappear and the under portion of the cap 34 always bears upon the washer 38. Under such a condition, the resilient and yieldable character of the washer 38 still assures proper seating ofvalve by the spring i6.

It will be apparent from the foregoing thaty the spring-3l maintains the main body portion 25 and the cap 34 respectively in contact with the cam I1 and the valve stem I3 and that the clearance provided to compensate for expansion of the valve mechanism appears between the Aparts of the valve lifter and not between the valve lifter and the valve stem. Thus, with the parts of the valve lifter constantlyv in engagement with the cam and the valve stem respectively, there are no metal to metal impacts at those points. The entire impact resulting from the rapid movement imparted to the valve lifter by the cam l is taken between the washer 38 and the cap 34, and thus is cushioned and silenced both because of the resilient character of the washer 38 and because of the beveled underneath surface of the cap 34 causing a gradually` increased area of contact between the washer and the cap.

Fig. 3 shows a modied form of valve lifter in which'a cam operated part 2|' is formed partly by a cylindrical member 25 having a bore 26' therein opening through the end remote from the cam shaft. The second part 22 is formed by a cap 4| having a diameter substantially equal vthe cap will not stick. The cushioning means interposed between the two parts of the valve lifter herein comprises a plurality of annular washers 38' of a resilient but substantially incompressible composition not affectedy by heat and oil, such as the commercial product known as Dum-ene. These washers have an outer diameter substantially equal to the diameter vof the bore 26' and an inner diameter substantially equal to the diameter of the stem 42.

Interposed betweenv the washers 38' are a pluralityof shims 38 having an outer diameter which is less than -the diameter of the bore 26'. As a result, a plurality of spaces 44 are formed into which the composition of the washers 38 may expand when the washers are placed under compression during the unseating of the valve by the valve lifter or upon expansion of the valve mechanism. The total distortion of the washers 38 into the spaces 44 is comparable to the clearance to be maintained in the valve mechanism when cold. In this forml the washers 38' serve the dual function of separating the main body portion 25 and the cap 4| to maintain them respectively in contact with the cam shaftand pression of the washers 38 in case of deterioratil which may not be exceeded during the unseating of the valve by the valve lifter.

tions thereof.

Fig. 4 shows a form of valve lifter embodying the features of this invention which is particularly well adapted for substitution in existing' valve actuating mechanism for it entails the replacement of a smaller part of the mechanism than does the form shown in Figs. 1 to 3. To that end a cup-shaped member 28 is formed -with an axial tubular extension A5 which is received within the threaded end of a standard valve lifter body portion 25". A washer d5 may be inserted above the body 25" as shown to strengthen the bottom of the cup-shaped member. The cup-shaped member 28 thus may readily replace the adjusting screw and lock nut normally threaded into the body portion 25" to provide for adjustment of the clearance normally maintained in the valve actuating mechanism.

The valve stem part of the valve lifter in the form. shown in Fig. 4 is composed of a cap 3Q" and a materially fore-shortened plunger 33", the cap fitting partially within the cup-shaped member to be guided thereby. Projecting axially beyond the cap 3&3"- is a valve stem engaging boss 35" while the inner face of the plunger is formed with a recess 36". This recess forms a seat for one end of a compression spring 3l", the other end of which abuts the bottom of the tubular extension 45 to separate the parts of the valve lifter in the manner of and for the same purpose as the spring 31 ln the form. shown in Fig. 2. Interposed between the cap 36" and the cupshaped member 28 to cushion the impact of the parts is an annular washer 38" like that shown in Fig. 2. Shims 39 are preferably interposed between the washer 38" and the bottom of the cup-shaped member 28 to enable the clearance to be adjusted. The underneath surface of the cap 34" is again beveled to ease the impact and to insure separation of the cap from the washer 38".

It is believed readily apparent that the invention provides a simple and inexpensive means for .insuring quiet operation of the valve actuating mechanism, and furthermore that it may be embodied in forms which nt into existing valve actuating mechanism merely by the removal of porrIhus in the forms illustrated in Figs. 2 and 4, the invention is adapted for injstallation in existing valve mechanism by remov` ing the adjusting screw and nut portions thereof and axing the invention to the standard valve lifter parts 25 and 25". In the form illustrated in Fig. 3, it is contemplated that the existing valve lifter part will be completely replaced or that this form may be embodied in valve mechanisms when originally designed. It is, of course, contemplated that various features of the invention may be embodied in original valve mechanism designed to obtain even further simplification. For example, the valve stem part 22 might readily be formed integrally with the Valve stem. i3.

By maintaining the valve stem and cam shaft parts of the present invention in continual contact with the valve stem and cam shaft respectively, and providing a cushioning engagement between the parts, there will be no impact blows between two metal parts during the operation of the mechanism as is the case in the present day valve mechanism wherein clearance is provided between the-upper end of the valve lifter and thc valve stem.

By making the washers 38 with a contact area many times that of the lower end of the valve stem I3, the pressure per unit area on the composition washer is low enough so that the washer i Ato provide accessibility for valve adjustment.

Since there are no screw devices used for adjusting the valves, shims serving this purpose, the adjustment will be more permanent and will yeliminate the tight and loose valves nowadays caused by vibration changes of the screw device adjustments. Heretofore shims were-not practical because of the small contact area of the valve lifter parts limiting the size of the shims so that the pressures encountered during operation would crushand destroy them, but the invention herein disclosed, which increases the area to many times that of the valve stem, makes it possible to use thin metal shims for adjustment purposes when the valve mechanisms are initially installed.

Although the invention is herein illustrated and described in connection with an L-head type of engine, it is to be understood that the invention in its various forms is equally suitablev forv use in connection with overhead valve engines wherein the valve operating member 22 would engage the usual push rods of the valve mechanisms of such engines. Since overhead valve engines are well known in the art, it is not thought necessary to illustrate the valve actuating mechanism thereof herein. In overhead valveengines all adjustment screws and lock nuts usually furnished on the rocker arms will be eliminated just as adjusting'screws and lock nuts are eliminated in the valve mechanism illustrated.

I claim as my invention:

1. In an internal-combustion engine having a cylinder block, a cylinder, a port opening into the cylinder and a valve controlling the port, valve vactuating mechanism comprising a cam shaft and a valve lifter interposed between the shaft and the valve comprising a tubular member adapted to be operated by said cam shaft and guided for longitudinal reciprocatory movement, said member having an axial bore opening through the end remote from the cam shaft, a

In the form illustrated in cup-shaped member having a central aperture periphery of the cup forming a hub for mounting the member on said tubular member, a washer of heat and-oil resistant, resilient composition in said cup-shaped member and a plurality-of shims interposed between the bottom of said cup-shaped member and said washer to determine the position of the washer in the member, a valve operating member having a cylindrical portion slidable in the bore in said tubular member and a disklike cap portion adapted to engage the washer to be limited thereby in im movement relative to the tubular member, said disk-like portion being beveled on its washer engaging face, and a compression spring disposed in the bore with one end abutting the end of the tubular member and the other end abutting the valve operating member to maintain'the same respectively in engagement with the cam shaft and with the valve.

2. In a valve lifter for valve actuating mechanism, a rst part having a cup-shaped member at one end thereof, a second part mounted for joint movement with said first part and for limited movement relative thereto having an annular radial flange, the adjacent surface of which has the shape of the frustum of a cone having its apex toward said first part, and an annular washer of resilient material mounted in said cupshaped portion and having' a flat surface adapted to contact the frusto-conical surface of the ange progressively as the parts are moved toward each other.

3. A silencer for valve actuating mechanism comprising, in combination, a rst member having a tubular portion insertable in the adjusting screw hole of a valve lifter and an enlarged annular iiange extending outwardly from the upper end ofsaid tubular portion and an upright annular wall extending peripherally of said fiange to form a cup-shaped end, a plurality of shims positioned in said end, a member of synthetic resilient material positioned against said shims and within said wall, a second member comprising a disk portion having its underneath surface beveled and in engagement with said member, an abutment on its other surface for engagement with a valve stem, and a coil spring positioned within said tubular portion of said rst member and engaging the adjacent side of said second member for maintaining said members in contact with said valve lifter and valve stem respectively,

4. In a valve actuating mechanism for internal combustion engines, a valve lifter adapted to be interposed between the cam shaft of the en- .gine and the valve to be actuated comprising, a

first part adapted to be operated by the cam shaft having a depression at the top thereof, a second part adapted to operate the valve comprising a radially extending annular portion having a face at the side thereof opposite the first part and an axial central portion extending toward said first part, and an annular resilient member supported in the depression comprising material yieldable under pressure having a face opposite the face on said second part and a central aperture adapted to receive said axial central portion so as to serve as a cushioned guide for said axial portion, said faces being separated from one another by distances increasing outwardly from the central portion to provide upon the yielding of said member an area of contact variable progressively in quantity during operation of the device.

5. A valve silencing device for insertion between avalve cam and valve stem of an internal combustion engine comprising, in combination, a tubular member in contact with the cam having a cup-shaped upper end, an annular resilient member of substantial thickness confined radially entirely within said cup-shaped end, a plunger having a central portion reduced in cross section to form a stem extending within the central aperture of the resilient member and laterally cushioned thereby, a substantial elastic means in the tubular member in contact with the plunger adjacent the reduced end for urging said plunger in a longitudinal direction, said plunger having a flanged central portion provided with a face adjacent the resilient member of a frustoconical shape with the apex thereof in initial contact with said resilient member adjacent the central aperture and adapted to provide an increase in contact area therewith in a geometric ratio as the pressure on said device increases, and an upward extending portion on said plunger ln contact with the valve stem.

6. A valve actuating device for insertion between the cam shaft and the valve of an internal vcombustion engine comprising a first member adapted to be operated by the cam shaft and guided for longitudinal reciprocatory movement, said member having an axial bore opening through the end remote from the cam shaft, a cup-shaped member mounted on said last mentioned end of said rst member, an annular washer of heat and oil resistant resilient composition in said cup-shaped member, and a plurality of shims interposed between the bottom of said cup-shaped member and said washer to determine the position of the Washer in the cupshaped member, a valve operating member having a cylindrical portion projecting into the aperture in said annular washer to be guided thereby and a disk-like cap portion to engage the washer to be limited thereby in its movement rela-tive to the cup-shaped member, said disk-like portion being beveled on its washer engaging face, and a compression spring disposed intermediate said first member and said valve operating member toA maintain the same respectively in engagement with the cam shaft and with the valve stem.

'7. A silencer forv valve actuating mechanism comprising, in combination, a first member having a cup-shaped end, a plurality of shims positioned in said end, a member of synthetic resilient material positioned against said shims and within the cup-shaped end, a second member comprising a disk portion having its underneath surface beveled and in engagement with said resilient member and an abutment on its other surface for engagement with a valve stem, and a coil spring positioned intermediate said first member and the adjacent side of said second member for separating said members.

- OSCAR H. BANKER-

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