US1185516A

US1185516A - Valve.

Info

Publication number: US1185516A
Application number: US637?515A
Authority: US
Inventors: Frank Macvicar
Original assignee: Individual
Current assignee: Individual
Publication date: 1916-05-30
Anticipated expiration: 1933-05-30

Description

VALVE. APPLICATION IFILEUKNOV. 21. 1915.

1,185,516. Patented May 30,1916.

3fm/nemica F. MACVIC/IR` VALVE.

APPLICATION FILED NOV. 27. I9l` Patented May 30,1916.

2 SHEETS-SHEET 2.

riiANK MACVICAE, or sYEAcUsE, NEW YORK.

VALVE.

Specification of Letters Patent.

Patented May 30, 1916.

Application mea November 27, 1915.v serial No.

vsprings fail to cause the tappets to iemain in engagement with the cam when the latter travels at a high rate of speed, thereby materially decreasing the efficiency of the motor, and necessitating the cam to operate against both the resistance of the spring and the pressure of the valve, thus subjecting the cam or cams to-undue wear.

It is the primary object of my invention to eliminate these objections, by providing a cam controlled valve mechanism, embodying a yieldable means for holdingr the tappets in continuous engagement with the opening and closing cams respectively, the closing cam possessing a greater throw than -the opening cam with a view of tensioning said yieldable means for the purpose nientioned.

Another object of importance resides in the provision of the above mentioned mecha. nism, wherein said yieldable means serves to cushion the eitra throw of the closing cam,

'thereby eliminating bottoming as the valve engages its seat.

In carrying out my invention I aim to provide a cam controlled valve mechanism, which will materially lessen the wear upon the cams and necessitate the use of less power to operate said valves.

The nature and advantages of the invention will be thoroughly understood when the following description Ais taken in connection with the accompanying drawings, the invention residing in the construction, combination and arrangement of parts as claimed.

In the drawings forming part of this speciicationlike numerals of reference indicate similar parts throughout the .several lviews and wherein:-

Figure 1 is an elevation of the preferred form of the invention 'showing the normal position of parts when thevalve is closed. Fig: 2 is a similar view showing the active position of the parts when the vvalve is opened. Fig. 3 is a perspective view of the cam. Fig. 4 is an elevation of a modified form ofthe invention showing the valve closed. Fig. 5 is a similar view showing the valve opened.

Referring to the drawings in detail, 5 indi-- Cates the engine cylinder'having the usual seat 6 and the inwardly opening valvel?, the stem 8.of the latter being slidably mounted within the guide'Q and adapted to be operated in the mannerv to be presently described. As shown in Figs. land 2 I make use of a pair of spaced

superimposed rocker arms

10 and 11 respectively, which arms are fulcrumed at a point approximately midway of their length as at 12. The rocker arm 10 is operatively associated in any suitable manner with the upper end of the valve stem 8 while the lowermost rocker 11 has its forward end provided with an opening 13 through which thestein is adapted toslide. The opposite end of each rocker carries a roller 14 and 15 respectively, the latter normally engaging'th'e cam 16 while the roller 15 normally contacts the cam 17, which cams are arranged upon the shaft A18. Encircling the stem 8 is a coil spring 21 disposed between the

rocker arms

10 and 11 respectively. "The spring has one end seated upon the forward end of the rocker arm 11 while the opposite Yend of the spring engages a nut 22 adjustably mounted upon the valve stem 8 at its upper end, and by means of which the tension of the spring can be readily and easily regulated. In the position of parts as shown in Fig. 1, the spring is compressed and under tension, for the expressed purpose of maintaining the rollers 14 and 15 in continuous engagement with their respective cams, irrespective of vthe speed at which these cams may travel. The cam 1G is of usual construction, and when the actuating surface 19 thereof engages the roller 14, the rocker arm 10 is moved upon its fulcrum depressing the valve stem 8 and moving the valve to opened position as clearly illustrated in Fig. .2'. In this position of parts the roller 15 is received within the depressed or dislied portion .20 of the cam 17, which portion is arrangeddiametrically opposite the actuating surface 19 of the cam 16 and which arrangement permits of" the expansion of the' spring 2l.

o the casing 34 is closed bymeansA of a nut It is of course to be understood thatas the actuating surface 19 of the cam 16 is moved out of engagement with the roller 14, the

,cam 16 is also being rotated to bring its highest portion of the depression 20 into active engagement with theroller 15, at which time the stem 8 is moved in a reverse direction for the purpose of seating the valve 7. It is manifest from the relative dimensions and formations of the respective cams 16 and v17, that the closing cam 17 has a greater throw than that possessedby the opening cam 16, by reason of which fact the spring 21 is not 1n any way affected by the operation of the cam 17 in the clos-` ing ofthe valve.' However subsequent to the seating of the valve 7, the spring 21 serving as a cushioning means to take care. of the extra throw of the closing cam 17, is compressed and movement equal to the dierence between the throws of the respective cams,

during which operation of the spring, the latter is again placed` under tension in the position of parts shown in Fig. 1, for the -position in the cylinders.

are constructed and arranged upon the shaft` 25 in identically the same manner as the

cams

16 and 17 respectively as hereinabove described. However the tappet as shown in this form of the invention preferably consists of a rectangular frame 26 within which the shaft 25 and the cams are arranged to operate. It might herel be stated that -this embodiment of the invention may be arranged immediately above the valve in the manner illustrated or it can be used by placing the cam shaft in the base of the motor and also where the valves are in horizontal A The upper and lower members 27 and 28 of the frame arel provided with semicircular projections 29 u and 30 respectively, the closing cam 24 operating upon the projection 29 around its entire circumference, while thev actuating surface 21 of the openingvcam 23 operates upon the projection 30. The lower member 28`has depending centrally therefrom an extension 32 slidably fitted within a suitable guide 33 and carries at its free end a relatively large casing 34. The lower end of 35 which is adjustably associated with the casing, and slidably passed through the central opening in the nut is a vvalve stem 36 6.5 ,of the valve 37 .-The upper endfof the valve stem is normally spaced a slight distance from the adjacent end of the casing 34, which distance .is equal to the difference of throw between the opening and closing cams respectively, the purpose of which will be presently described. Arranged within the casing 35 and encircling the stem 36 is a coil spring 39 having one end seatedy upon the nut 35 and its opposite end engaging a nut 38 adjustably mounted upon the upper end of the stem 36 for the purpose of regulating the tension of the spring. j Y

N ow las the shaft 25,is rotated and the actuating surface 31 of the cam 23. brought into engagement with the projection 30, the tappet including the frame 26, extension 32, and casing 34 is moved against the valve stem 36, therebymoving the ,valve 37 away from its seat, Aas 'shownin Fig. 5. vIn the normal or closed position of the valve as shown in Fig.4the spring 39 is compressed and under t4a'nsi`on,`.y but when the valve is moved to opened position as shown in Fig. 5 this spring ispe'r'mitted to expand, thereby moving the valve 4 stem 36 into engagement with the upper end of the casing 34. As the shaft 35 is rotated to. move the actuating surface 31 of the cam 23 out of engagement with/the projection 30, the caml 24 is simultaneously'rotated 'to bring the highest portioriof the? depleion 40 thereof into engagement with the projection 29 thereby moving the tappet in its entirety in a direction 'opposite that-in `which it was moved by the cam 23 for the purpose of seating the valve 37. The relative dimens4 f sions and formations of the respective cams,

attributes to,. the closing cam 24 a slightly` greater throw@ than that possessed by the opening cam 23, and subsequent to the'closing ofthe valve 37 by means of the cam 24, the

ter, which not only eliminates considerable wear upon these parts, but renders the valve to be more easily and properlytimed when the cam shaft travels at a high rate of speed. While I' have shown and described several embodiments of the' invention I desire -to have it understood that I do not limit myself to this precise' construction and ar- 1. The combination with a cylinder of an ,12.5 rangement of parts, and that variouschanges f internal combustion engine, anda valve therefor, of valve operating mechanism including opening and closing cams respectively, a valve actuating device adapted to engage the opening and closing cams rev for, of valve operating mechanism including opening and closing` cams respectively, a valve actuating device adapted to engage the opening and closing cams respectively,

a-syieldable means for vholding said device in continuous engagement' with saidcams, and means for regulating the tension of said yieldable means.

`3; The combination with a of aninternal combustion engine, and a- `valve v therefor, of a valve operatingl mechanism including opening and closing cams respec-l tively, a valve actuating deviceadapted to engage the opening and closing cams re- 25 spectively, yieldable means normally under tensionforholdin said devicein continuous engagement with said earns, `'one of said ,earns decreasing the tension of said means,

and thevother of said cams placing said means under tension.

- 4. The'combination with a cylinder of an internal combustion engine, and a valve therefor, ofayalve o erating mechanism in# 'cluding opening an 'closing cams respectively, a valve actuating device f adapted to' engage said cams, an extensile spring encircling 4the valvestem and operating to hold the valve actuating device in continuous enr gagement with the respective cams and means for regulating the tension o said spring.

5. The combination with a cylinder of an internal combustion engine, and a valve therefor, of a cam controlled valve mechanismv including a tappet operatively associated withv the valve and adapted to engage the opening and closing cams respectively, a. yieldable means operating'to hold said tappet in continuous engagement with said cams, and said closing cam having a greater throw than the opening cam for compress# ing and placing said'yieldable means under tension as described. l

6. In combination with a cylinder of an internal combustion engine, and ya valve therefor, of a tappet including a pair ofspaced parallel rockingarms, one of said arms being terminally associated with the S'tem of the valve, said stem being slidably fitted in the adj-acentend of the other of said' arms, a cam for operating said `arms to open the valve,- asecond cam 'operating to close said valve, a yield' able means interposed between said arms operating tov hold the latter in continuous engagementwith their respective cams, and one of said cams having a greater throw --than the other for compressing and placing said yieldable means under tension.

' In testimon whereof I -affix my signature in presence o two witnesses.

. FRANK MAQVICAR.

Witnesses: l t

CHARLES MACVICAR,

EDITHl M. MACVIGAR.

capite# of'tll patent my be obtainedptpr ive centsY each, by addressing the Commissioner of Intenta,

washington, D. c."