US2674985A - Rotating valve - Google Patents

Description

April 3, 1954 R. CARLIN 2,674,985

ROTATING VALVE Y Filed Nov. 1 ,1949

6 7 W a a a I f Q' Q y. g 1 -43 36 {i /a 1 44 x 20 u 1T7 /7 H /5 II I 22 /6' 33 /9' 1131:?

Patented Apr. 13, 1954 ROTATING VALVE Robert Carlin,

Milwaukee, Wis., assignor to Allis- Chalmers Manufacturing Company, Milwaukee, Wis., a corporation of Delaware Application November 1,

1949, Serial No. 124,871

6 Claims. (Cl. 123-90) This invention relates generally to valve construction and is more particularly directed toward the construction of poppet valves for internal combustion engines.

In the operation of internal combustion engines it is essential that the poppet valves function properly and it is particularly important that each exhaust valve is fully closed during the compression stroke of its related piston. In the poppet type exhaust valve, which is arranged in the cylinder head with a unitary stem actuated by a cam operated tappet, it has been found that the extreme temperature conditions in the exhaust chamber give rise to rapid deterioration of the valve head when provision is made for only axial movement of the valve. This rapid deterioration is brought about mainly by the carbon deposits formed on the valve stem and seat which cause the valves to stick and wear unevenly.

To avoid this difficulty it has been found desirable and effective to make some provision for rotating the valve slightly with each stroke. This rotation keeps the stem free of deposits and thus prevents sticking which is a valve burning. Furthermore, such rotation imparts a wiping action between the valve head and seat to prevent the build-up of deposits therebetween and, consequently, makes for better thermal conductivity resulting crating valve heads. Also, the elimination of such deposits precludes the flaking off of portions of the head which would allow blowby and subsequent burning. Many different devices have been designed to efiect a. rotation of the valve during each stroke of operation either through positive rotation of the valve or by momentarily releasing the restraint on the valve so that it is free to rotate. The present invention is directed to the latter type means, hereinafter referred to as a nonpositive rotating means.

In the construction of nonpositive rotating means it has been fairly common practice to utilize a rotatable cap freely seated on the upper end of the tappet in encircling relation to the lower end of the valve stem and so arranged that the end of the valve stem is relieved of pressure from the cap for an instant during its cycle of operation thereby allowing the valve to rotate relative to its seat. However, it has generally been found that in new engines and in engines which remain idle for a considerable length of time the valve stem frequently sticks in its slide and remains open during the first few strokes of the cylinder, during which time the rotator cap is free to follow the tappet without common cause of in cooler op- I the benefit of the valve stem as a guide means. Consequently, the cap usually falls to one side and, when the valve frees itself and moves to its closed position, the cap becomes lodged between the end of the valve and its tappet which prevents seating of the valve. Furthermore the pressure of the tappet and valve stem on the cap lodged therebetween is frequently sufficient to break the cap and considerable time is lost in extracting the broken pieces from the engine.

Nonpositive rotating means have been designed heretofore which have avoided the above mentioned difficulty by fixing the rotating means against axial separation from the valve stem but the known designs have not proven to be too satisfactory. The known constructions have not afforded easy detachment of the rotating means from the valve stem for purposes of repair or replacement and, since such means are subject to constant wear, this is a serious defect. Furthermore, these prior devices have generally included an assembly of parts occupying a relatively long section of the valve stem making such assemblies undesirable for use in small engines since the valve guide length is decreased through use of such rotating means to a point wherein. such guide length is insufficient to properly guide the stem throughout its full range of movement.

It is, therefore, a primary object of the present invention to provide a new and improved nonpositive rotating means for use with a poppet type valve assembly affording relative rotation between the valve and tappet and limiting the relative axial movement between the valve and rotating means.

A further object of this invention is to provide a nonpositive valve rotating means positionable between the valve and tappet which is constructed and arranged in a novel manner affording easy attachment and removal thereof with respect to the valve stem. Another object of this invention is to provide a means, for use with an engine valve assembly and affording rotation between the valve and its seat, which is detachably fixed to the end of the valve stem and occupies a relatively short section therealong.

It is also an object of this invention to provide a nonpositive valve rotating means which is simple, inexpensive to manufacture, easily manchined to afford proper clearances and which can be readily replaced without removing the valves from the engine.

Further advantages afforded by apparatus embodying the present invention will become l sliding movement relative 18 isflanged to urge valve -under side of elements l1 -thereof provides a; seat for.

valve stem. In order toloosely.maintaincapil in. position relative to spring seat. 18. there is provided a resilient. circularretainer element,"

"nular shoulder portion 23 portion 23 and groove 25 to pment-otcap M -For moving valve 5 upwardagainst-the pressure of spring .tional assembly "camshaft 3| 1 tappet 2lprovides themeans for operating the more apparent as the disclosure progresses and particularly points out details of construction and features not mentioned hereinabove, with reference being had to the accompanying drawings, in which: i V

Fig. 1 is a partial view of an internal combustion engine embodying the present invention with parts omitted or broken away for sake of clarity;

Fig. 2 is an enlarged view of the spring seat and adjacent parts shown in Fig. 1; and. V

Fig. 3 is a view of the parts shown inFigL 2 with the spring seat moved out of supported engagement with the rotatable cap at the end of the valve stem.

Referring particularly to Fig. 1 it will be seen that apparatus embodying the present invention comprises generally an internal combustion en- =gine block I having a poppet valve assembly controlling exhaust port 3 of i each cylinder (not shown) of the engine. The valve assembly comprises a poppet type valvejhayin'ga head portion 6 coacting with seat 7 .formed in the engine block. to'prevent escape of gases from the cylinder to the exhaust passage 8 and a stem portion it which extends through a guide part I I. secured in a vertical bore. [2 in the block, for thereto. The lower portion of stem [0 has an inwardly tapered portion [3 merging with a reduced cylindrical in- ;termediate portion M which in turn terminates in a-rrelatively. enlarged cylindrical portion thereby form a shoulder l6 (Fig.2) near the end oi the valve stem. I

A-pair of complementaryring forming eleme s l'l-are positioned on shoulderltprovid- .ing a retainer and support. mean onth valve stem .for-a bell shaped spring seat part, 18. A compression'spring is disposed inencircling relation to the valve stem with .the upper coil 7 of the spring engaging a seat It formed in the IE to engine block and the lower coil positioned one radially outwardly flanged lowers-portion of spring seat l8; The upper part'of spring seat inwardly for engagement withth top side of elements I1; and it is thusseen that spring 2ll, spring-seat l3 and retainers I1 coact in a downward direction. a

A-hollow cylindrical cap like element 2|. have Y ing its lower end closed, is positioned in receiving relation to -enlarged end portion lief. stem 10 and is rotatable relative thereto. .The upper. end of cap 2| is positioned for engagementwith the and theclosed end the lowerend of the .21 and abuts an aniormedph the outer surface of thecap. ,A circumferential groove which is pressed on tofcap 25 having a depth somewhat greater. than the 20 there is provided a conven '26 comprising avalve tappet. 2i, adjusting screw 28 and-lock; nut--29. be rotatable having cam 32 thereonengaging tappet and valve assembly. Since the valve actuating meansis conventional and formsno surface of shoulder portion over shoulder 23 essential part of the present invention it is believed that a further description thereof is unnecessary. v

Having described the construction and arrangement of parts in the valve assembly, a detailed description will now be given of the manner of attaching and removing rotatable cap 2| with respect to the assembly. It will be noted in Fig. 2 that when spring seat l8 and cap 2| are in their normal operating positions the resilient retainer element 22 abuts the lower edge of shoulder portion 23 on cap 2| and is partially disposed in groove 25 on the adjacent surface of the spring seat. From this position cap 2|,together with elements I! and spring seat, |8,.may move axially relative to valve 5 a limited distance, that is, upwardly to take up the axial clearance between the bottom surface of the valve stem portion 15 and. the internalbottom surface of cap 21. Axial separatingrnove- 'ment of cap 2| from retainer I8 is restrained by contactbetween ring-22 and lower inwardly facing corner edge 34 of groove 25 and by contact between ring 22 and the lower axially tapered When it becomes necessary to detach cap 2! from the valve assembly this may be readily accomplished by holding valve 5 in its closed position (Fig. 1) and moving spring seat lfi upward relative thereto. The upward movement of the spring seat causes lower-edge 34 ofgroove 25'to engage ring 22 and force it up over shoulder 23. Ring iz being resilient (and preferably less than a complete circle) can expand suificient to pass and movet'o its position shown in Fig. 3. And in this conne'ction itshould be noted that the outside diameter of cap 2! above shoulder 23 is less than the outside diameter below the shoulder. Cap 2i is so formed in order that the cap and ring] when the latter is; positioned as shown in Figs. land 2; cannot moveaxially beyond the limit ofedge 34 of groove 25, but when resilient ring 22 is moved 'to'the position shown in Fig. 3, wherein it contracts to down past the lower conform with the size of the cap at such point,

be desirable to remove [the entire'valve assembly from the block this may be quickly accomplished by moving the spring-seat relative to the valve stein, as 'described above, and then withdrawing the semieircular elements of retainer IT from their position on the stemjan'd finally'reinovingcap 2|. And i thisfconne'ction it should be noted that v the outside diameter of enlarged cylindrical porameter of guide part H.

tion J5 on the endfof the valve stem is slightly less than the inside diameter of the opening 35 .through the upper surface of thespring seat and also removably conforms with the internalfdb Consequently, the stem .maybe readily passed upward through opening 136 and the opening through guide part ii once retainer elements, i! are removed. And with valve 5 removed the springseat"and'springare alsofllfree to be removedl The idiam'eterfof the .e gqwc edge 33 is somewhat smaller tha nfthe diameter of the groove edge 34, and'ior purposes of assembly, after the parts have been arranged as shown in Fig. 3, the spring seat l8 may be moved downwardly relative to the valve 5 until the edge 33 engages the ring 22. Continued downward movement of the spring seat 48 will then force the ring 22 downwardly over the shoulder 23, the axially tapered upper surface of the shoulder 23 first expanding the ring, and the axially tapered lowered surface of the shoulder subsequently permitting the ring to contract until it becomes seated on the large diameter part of the cap 2| as shown in Fig. 2.

Having described the structure embodying the present invention, the operation thereof will now be explained. Fig. 1 shows the valve assembly in closed position just prior to being opened (assuming that cam 32 is rotated in a clockwise direction). In this closed position tappet assembly 26 is at the bottom of its stroke with screw 28 engaging the bottom of rotatable cap 2 I. The upper edge of cap 2| bears against retainer H and a clearance is present between the end of valve stem Ill and its opposed interior seating surface on cap 2|.

Further movement of cam 32 clockwise causes an upward movement of tappet assembly 26 and the initial portion of this upward movement effects a thrust upon cap 21 which lifts retainer I! from valve shoulder l6 and valve 5 is momentarily unrestrained and may rotate in response to gas forces on the valve and relative movement of associated parts of the engine. Continued upward movement of tappet assembly 26 brings the internal seat portion of cap 2| to bear against the end of the valve stem and thereafter moves the valve to its fully opened position. Thus it is seen that valve 5 is free to rotate relative to its seat for a short period of time during the opening end of the valve operating cycle.

In general terms, a device incorporating the invention comprises valve closing means including an annular first element surrounding an end portion of a valve stem in axially shiftable relation thereto, resilient means operative to urge said first element in valve closing direction, axial thrust transmitting means associated with said first element and complementary abutment means associated with said valve stem for transmitting movement of said first element in valve closing direction to said valve stem and permitting movement of said first element in valve opening direction relative to said valve stem. In the illustrated embodiment of the invention, the annular first element is represented by the spring seat iii, the lower outwardly flanged portion of which supports the resilient means 20 and the upper inwardly flanged portion of which along with the ring elements l1 form the axial thrust transmitting means which is engageable with complementary abutment means 16 to transmit movement of spring seat It in valve closing direction to the valve stem l0. Valve opening means include a second element movable axially into and out of said first element and presenting a tappet engaging outer surface, an oppositely facing valve stem engaging surface, and an axial thrust transmitting portion disposed in axially opposed relation to said thrust transmitting means for cooperative engagement therewith in valve opening direction so as to permit simul taneous movement of said first and second elements in valve opening direction independently of said valve stem. In the illustrated embodiment of the invention such second element is represented by the cap 2|, the open end of which is engageable in valve opening direction with the complementary ring forming elements H in order to move the valve seat 18 in valve opening direction relative to the valve stem I0. Relatively engageable and disengageable connecting means include a detachable retainer element which, in the illustrated embodiment of the invention, is represented by the radially contractable and expandable ring 22 which is operatively interposed between the spring seat l8 and the cap 2| for releasably locking the spring seat and cap against axial separation from each other.

And although shown and described with reference to a particular valve assembly it should be understood that it is not intended to thereby limit the invention as various modifications within the scope of the appended claims may readily occur to those skilled in the art.

It is claimed and desired to secure by Letters Patent:

l. A seat assembly for operatively connecting a poppet valve and tappet mechanism, comprising valve closing means including an annular first element surrounding an end portion of said valve stem in axially shiftable relation. thereto and having a circumferential groove formed in its inner surface, valve opening means including an annular second element movable axially into and out of said first element and presenting a tappet engaging outer surface, an oppositely facing valve stem engaging inner surface, and a surface portion engageable with said valve closing means and so related to said valve stem engaging inner surface that, upon movement of said second element in valve opening direction, said closing means will be moved in valve opening direction relative to said valve stem prior to engagement of said inner surface with said valve stem, said second element having a circumferential axially tapered shoulder portion formed on its outer side wall opposite said groove, and a radially contractible and expandable retainer ring having a cross sectional diameter less than the depth of said groove and embracing said sec ond element in axial load bearing relation to the tapered surface of said shoulder and coacting with said groove to releasably lock said first and second elements against axial separation from each other.

2. A seat assembly for operatively connecting a poppet valve stem and tappet mechanism, comprising, a valve stem having a portion of reduced diameter adjacent the tappet end thereof, an annular bell shaped spring seat element surrounding the tappet end portion of said valve stem in axially shiftable relation thereto, complementary ring forming elements surrounding said reduced portion of said valve stem and being disposed within said spring seat in supporting relation thereto and for axial shifting movement in i valve closing direction against a shoulder on said valve stem, a generally cylindrical element disposed in coaxial relation between said valve stem and tappet mechanism, said cylindrical element presenting a tappet engaging outer surface, an

oppositely facing valve stem engaging inner surface, and a surface portion engageable with said ring forming elements and s0 related to said valve stem engaging inner surface that, upon movement of said cylindrical element in valve" opening direction, said ring forming and spring seat elements will be moved in valve opening direction relative to said valve stem prior to engagement of said inner surface with said valve stem, and relatively engageable and disengage able axial thrust transmitting means includin b e wi -parton;thetappet sideof said shoulder a larger than on the other tractable and expandable retainer ring having a cross sectional diameter less than said groove and embracing said cylindrical part teases tamer element operatively interposed between said ,springseat and cylindrical elements for releasably locking said, cylindrical element within said spring seat element against axial separation from the latter.

w seat assemblyior operatively connecting a, poppet ,valve stem and tappet mechanism, comprising, an annular bell shaped spring seat surrounding the, tappet end portion of the valve stem and having a circumferential groove formed in ,itsinner surface, complementary ring forming elements surrounding the tappet end portion ofsaid valve stem and disposed coaxially within said springseatin supporting] relation thereto and for axial shifting movement in valve closing direction against a shoulder on said valve stem, agenerally cylindrical hollow part disposed within said spring seat and presenting a stem engaging inner surface, and a surface portion engage said ring forming elements and so related to said valve stem engaging inner surface that, upon movement of said hollow part in valve opening direction, said ring forming elements and spring seat will be moved in valve opening j direction prior to valve opening engagement of said inner surface with said valve stem, said cylindrical part having an axially tapered shoulder formed on its outer side surface, and a radially contractable and expandable retainer ring positioned around said cylindrical part for coaction with said tapered shoulder and groove to limit axial outward movement of said part relative to said springseat.

4. A seat assembly for operatively connecting a poppet valve stem and tappet mechanism, comprising, an annular bell shaped spring seat surrounding the tappe't end portion of the valve stem and having a circumferential groove formed in its inner surface, complementary ring forming elements surrounding said valve stem and disposed coaxially within said spring seat in supporting relation thereto and for axial shifting movement in valve closing direction against a shoulder on said valve stem, a generally cylindrical hollow part disposed within said spring seat between said valve stem and tappet mechanism presenting a tappet engaging outer surface, an oppositely facing valve stem engaging inner. surface, anda surface, portion engageable witlrsaid ring forming elements and so related to said valve stem engaging inner surface that,

upon vmovement of said hollow part in valve opening direction, said ring forming elements and spring seat will be moved in valve opening ell-- rection prior to valve opening engagement of said innersurface with said valve stem, said cylindrical part having a circumferential sh0ul ,derportion formed on itsouter side wall opposite said groove, the diameter of said cylindrical being side, and a radially conthedepth of apoppet valve stem and tappet mechanism, comprising, valve closing means including an annular first element surrounding an end portion of said valve stem in axially shiftable relation thereto,

for releasably locking said "Number 8 resilient means operative to urge said first" element in valve closing direction, axial thrust transmitting means associated with said first element and complementary abutment means associated with said v'alve stem for transmitting movement of said first element in valve closing direction to said valve stem and permitting movement of said first element in valve opening direction relative to said valve stem; valve opening means including a second element movable axially into and out of said first element and presenting .a tappet engaging outer surface, an oppositely facing valve stem engaging inner surface and an axial thrust transmitting portion disposed in axially opposed relation to said axial thrust transmitting means for cooperative engagement therewith in valve opening direction so as t'o permit simultaneous movement of said first and second elements in valve opening direction independently of said valve stem, and relatively engageable and disengageable connecting means including a detachable retainer element operatively' interposed between said first and second elements for releasably locking said first and second elem'ents against axial separation from each other. 6. A seat assembly for operatively connecting a poppet valve stem and tappet mechanism, comprising, valve closing means including an annular first element surrounding an end portion of said valve stem in axially shiftable relation thereto and having a circumfer ntial groove formed in its inner surface, resilient means operative to urge said first element in valve closing direction, axial thrust transmitting means associated with said first element and complementary abutment means associated with said valve stem for transmitting movement of said first element in valve closing direction to said valve stem and permitting movement of said first element in valve opening direction relative to said valve stem; valve opening means including anannular second element movable axially into and out of said first element and presenting a tappet engaging outer surface, an oppositely facingvalve stem engaging inner surface, and an axial thrust transmitting portion disposed in axiallyoppcsed relation to said axial thrust transmitting means for cooperative engagement therewith in valve opening direction so as to permit simultaneous movement of said first and second elements in valve opening direction independently of said valve stem, and relatively engagealole anddisengageable connecting means including a radially contractable and expandable ring embracing said second element and cooperable with said groove first and second elements against axial separation from each other.

References Cited inthe file of this patent UNITED STATES PATENTS Date ' Name 1,213,599 Compton Jan. 23, 1917 1,462,160 Anthony July 1'7, 1923 2,142,224 Turlay June 3, 1939 2,165,238 Douglas et a1. July 11, 1939 2,165,239 Douglas ae a1. July 11, 1939 2,175,465 .Johnson Oct. 10, 1939 2,346,525 Voorhies Apr. 11, 1944 FDRE'IGN PATENTS Number Country Date 428,998 Great Britain May 22, 1935

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