US1586188A - Internal-combustion engine - Google Patents

Description

' May 25,1926. 1586,188

R. F. FISHER INTERNAL COMBUSTION ENGINE Filed March 31 1921 4 Sheets-Sheet 1 3 fizzy! wz'ineswm iwi gy J fizz/c7250?" May 25 1926. 1,586,188

R. F. FISHE R v INTERNAL COMBUSTION ENGINE Filed March 31 1921 4 Sheets-Sheet '2 'Wz'izz 8S5 72142722 0? flMJJW N v HZZdrneyJ/QO-Q4 AW May 25 1926.

R. F. FISHE R INTERNAL COMBUSTI 0N ENGINE Filed March 31 1921 4 Sheets-Sheet 3 Wz'ines's a uztw-m 1721267220? WJJMQL' May 25 1926. 158 6188 R. F. FISHER INTERNAL COMBUSTION ENGINE Filed March 51 1921 4 Sheets-Sheet 4 Patented May 25, 1926.

PATENT- OFF-ICE.

ROBERT F. FISHER, OF CLEVELAND, OHIO.

INTERNAL-COMBUSTIOLl ENGINE.

' Application filed March 31, 1921. Serial No. 457,195.

My invention relates to internal combustion engines, more particularly it relates to poppet valves thereof and to, means for controlling the same and to means associated therewith. Among the objects of my invention are the following:

To provide means for positively opening and closing a poppet valve;

To provide means for insuring a yielding connection between the cam shaft and the poppet valve;

To provide a universal joint connection between the cam and the poppet valve;

To provide other details of improvement tending to increase the efliciency and serviceability of an engine of the above character;

To accomplish the foregoing and other useful ends my invention makes use of means hereinafter more fully set forth and claimed.

Referringinore particularly to the draw- 1ngs:

Fig. 1 is a plan view of the valves, rockerlever, rocker-shaft and bracket.

- Fig. 2 is an end elevation of the rockershaft, rocker-bracket, rocker-lever, and rocker-lever block showing the use of a. universal joint in connection with the valve.

Fig. 3 is a section through the cam-follower lever showing its engagement with the cam-shaft of the groove type.

Fig. 4 is-a side elevation of the cam-shaft, cam-follower lever, and rocker-lever and operating rod. It will be seen that Fig. 4

is an enlargement from the lower section of Fig. 12, and that Fig. ,2is an enlarge. meat from the upper section of Fig. 13.

Fig- 5 is an .end elevation of the camshaft.-a section being taken through the cam-follower and a section also being taken through the engine frame. This figure also shows a side elevation of the cam-follower lever shaft.

Fig. 6 is a plan view of the camiollower and valve-rocker lever shaft, and shows the universal joint as well as a section of the engine cylinder.

Fig. 7 is a side-elevation of the valverocker lever bolted to the rocker-lever bearing block. r

Fig. 8 is a plan view of the cam-follower lever and cam rolls, and also shows in plan the flange type of cam-shaft.

Fig. 9 shows the cam-shaft in end clevat-ion, it also shows the cam-follower lever, cam rolls, cam-follower and valve-rocker.

lever shaft, valve-rocker lever, and a section of the engine frame and cylinder.

Fig. 10 shows in side elevation the cam .shaft of the taper-flanged type. It also shows a section through the taper rolls and cam-follower lever with a spiral spring cushion.

Fig. 11 is a plan view of the engine cy'linder showing the valve-rocker levers and bracket.

Fig. 12 shows in side elevation a single cylinder engine with my invention; the groove type of cam-shaft being shown.

Fig. 13 is a section on line 1313, Fig. 12.

Fig. 14 shows an engine cylinder in plan view using my invention. 7

Fig. 15 shows in side elevation 21 single cylinder engine with my invention using 7 the flange type of cam-shaft.

' Fig. 16 is a section on line 1616, Fig. 15.

Fig. 17 is a plan view on section line 17-17, Fig. 20.

Fig. 18, is a section on line 18-1-18, Fig. 20, showing cam and rolls on Fig. 17 more clearly. This cam is a modified form of the cam shown in Fig. 3.

Fig. 19 shows in side elevation a single cylinder engine with my invention, making use of the groove type of cam.

Fig. 20 is a section on line 2020, Fig. 19.

Referring more in detail to the drawings, it will be seen that I provide an engine with poppet valves positively operated both to 9 open and close.

Referring to Fig. 16, the valve is shown horizontally disposed, the stem of the valve projecting toward the left and terminating in a socket,w33. Associated with this socket, 33, there is a. spring, 48, mounted on the upper end of the rocker-lever shaft, 44. Said spring, 48, rigidly secured with re spect to the shaft, 44. The shaft, 44, on its lower end is provided with an inwardly extending arm, 43, on the end of which is socured the cam-shaft rolls, 22, mounted on the small shaft, 23.

Referring to Fig. 15, it will be seen that the cam-shaft 42 is provided with a pair of flange type cams both of which are shown engaging the cam rolls 22. This shaft, 42, is pivoted in the engine frame and insured against lateral play in any suitable manner as, for example, by the provision of-the flange, 55, on the left extremity, and the tuning gear, 54. As shown, the gear, 54,

meshes with the timing'gear, 53, which is mounted on the crank-shaft 52. Obviously, therefore, the rotation of the crank-shaft causes a rotationof the cam-shaft, 42. The rotation of this cam-shaft causes the rotation of the cams there-on and therefore causes the oscillation of the follower-lever arm, 43, about a vertical axis through the center of the rocker-lever shaft, 44. This, of course, causes a corresponding reciprocating movement of the shaft, 44, with the corresponding oscillatory movement of the spring, 48, previously referred to.

Referring to Fig. 15, the spring, 48, is provided with a socket on its right-hand terminal. This is more clearly shown by referring to Fig. 16. It was previously pointed out that there is also a socket on the end of the stem of the valve, 51, now, between these two sockets there is a connecting link consisting of a pair of balls one in each of said sockets, said balls being rigidly con-. nected through the medium of an interconnecting member, 32. These sockets together with these balls so connected form auniversal joint between the shaft, 44, and the valve, 51. The object in this arrangement is to insure smoother operation of the valve, 51, and to eliminate unnecessary strains due to the rotation of the spring, 48, about an axis through the center of the shaft 44.

\Vith respect to the spring, 48, it will be seen that by providing such a spring mem-' ber between the valve, 51, and the shaft, 44, I insure against any harmful results occurring to the mechanism as a result of the valve, 51, reaching its seat before the cam at the lower end of the shaft, 44, has reached the limit of its stroke. By providing a yielding spring such as the spring, 48, I prevent the connecting link between the;

. shaft, 44, and the valve, 51, being bent. In

this connection, I may say that I have another safety arrangement which will prevent the bending of the link,.48, in the event that it is not made flexible. In the event that the valve, 51, reaches its seat before the cam completes the limit of its stroke, if the arm, 48, is rigid, the pressure of the cam and the cam-shaft, 42, will resalt in forcing the rolls, 22, outwardly with respect to the cam, which, referring to Figs.

15 and 16, will. be downwardly, thereby, causing the shaft, 44, to be depressed or slid downwardly, causing a compression of the spring, 27 and thereby insuring against undue strain on the valve or any of the associate parts. I wish to point out further that the spring, 27, also serves to maintain the rolls, 22, in close working engagement with the cam on the cam-shaft, in other words, the spring, 27, serves a double purpose.

Referring to Fig. 14, for the purpose of the description, we may assume that the valve on the right-hand side is on the intake side, and, inasmuch as Fig. 16 is a section through this valve, the valve, 51, may be considered as the intake valve.

Although I have shown the invention in Fig. 15 in connection with flange earns, the groove type of cams such as shown in Figs. 17, 18, 12, 19, 20, and 3 may be used.

Referring more particularly to Figs. 20

and 19, it will be seen that I show my invention in these two figures in connection with an L head type of cylinder. It will be seen also that the valve is shown in a slanting position. It will also be seen that the valve is controlled through the medium of a groove type of cam but it will be understood that either of the other types of cams may be substituted. Regardless of which type of cam is used, it will be seen that the roll-shaft, 23, Fig. 16, corresponds to the pin or roll-shaft, 59, in Fig. 20, and it will also be seen that/the follower-lever, 43, in Fig. 16, corresponds to the follower-lever on which the pin, 59, is secured in Fig. 20. In both Figs. 16 and 20 the follower-lever, 43, is securely mounted on one end of a shaft which shaft in Fig. 16 is the shaft, 44, and in Fig. 20 is the shaft, 66.

In Fig. 16 the valve rocker-lever, 48, is mounted on the opposite end of the shaft, 44, to which the universal joint is attached. However, in Fig. 20 the follower-lever is provided with an extension, 60, to which the universal joint is directly attached without the interposition of a flexible arm such as the arm, 48, Fig. 15. However, in both Figures 16 and 20, the, spring, 27, is provided to maintain the cam rollers against the cam and to act as a safety device between the Qam-shaftand the valve as previously explained.

Referring more in detail to the operation of the means shown in Fig. 20, it'will be seen that the rotation of the camshaft, 64, causes the oscillation of the arm, 60, about an axis and coincident with the longitudinal axis of the shaft, 66. This oscillation causes a corresponding operation of the poppet valve. 68, throughthe medium of the universal joint. 32. It will be seen from what has already been said that in the event of the valve, 68, reaching its seat before the cam reaches the limit of its stroke,that the rollers, 61 and 63, will be forced out toward the \left, Fig. 20, causing a compression of the spring, 27, with the consequent sliding'of shaft, 66, in its longitudinal hearing which isshown in section.

Referring more in detail to the construction of the cam rollers, 61- and 63, it will be 7 whereas the small roll,

seen by referring to Fig. 18, that the roller, 61, engages the upper side of the cam groove 63, engages the lower side of the cam groove. Referring to Figs. 11, 12, and 13, it will be seen that in these drawings I show the application of my invention using the groove type of cam control to an over-head mounted vertical valve. It will be seen that between the follower-arm, 24, and the universal joint, 32, 1 provide a lever-rocker arm, 35, and a second universal joint terminating in the socket, 31, on either end, the balls in which are connected by the rod, 34.

It will be'understood from what has already been said that. the oscillation of the arm, 24, as a result of the rotation of the cam-shaft, will cause a reciprocal up and down motion of the shaft, 34, which. will causethe lever, 35, to rock about the shaft, 37, see Fig. 12, which in turn will cause the operation of the valve, 40. Therefore, the operation of the engine with the variation shown in Figs. 11, 12, and 13, agrees with the operation of the means shown in Figs.

19. and 20 except for the interposition of the,

links, 34 and 35.

In Figs. 2, 4,5, and 3, I show the application to the mechanism described in connection with Figs. 11, 12, and 13 of the type of cam arrangement shown in Fig. 3. In this type of groove cam, the upper surface ofthe groove, Fig. 3, is shown engaging the cam roll, 22, on the shaft orpin, 23, whereas the lower surface of the groove is shown engaging the roll on-a second similar roll on a second similar pinon the follower-lever, 24. Figs. 6, 7, 8, 9 and 10 are enlarged details of the cam arrangement shownin Fig.

Referring to Figs. 2 and 15, it is noted that the rocker-levers, 35, and 48, may be made of spring steel. By making these positive closing of the against undue strain as previously pointed out.

Referring to Fig. 3, it will be noted that the sides of the cam are sloped and the engaging element, see element 22,is sloped to prevent friction and to maintain a proper ratio between all of the contacting sections of the surface. a p

Referring to Figs. 4 and 5,'it will be noted that the lever, 24, is fastened to the shaft, 25, in any suitable manner as for example by the use of if ered pin 26. It will be understood, of that the shaft, 25, oscillates in the bearing, 30, which oscillating movement is produced. by the cam, .21. The lever-shaft and rolls are free to move endwise in the bearing, 30, infthe event of excessive strain and subject to the control of the spring, 27. The spring, 27, further maintains constant working engagement between the rolls, 22, andthe cam regardless of wear. The provision of the lengthwise movement of the shaft, 25, in the bearing, 30, serves to cushion the closing of the valve, 40, and also prevents damage to the parts in case the stem of the valve,val"e 40 for example,-should stick.

In an internal combustion engine using poppet valves, it has beenfound heretofore that with the increase of speed of the engine beyond a certain point the efficiency of the engine begins to drop off as'lt result of the poppet valve having to depend upon a spring to close the valve. With my invention, I insure the positive action of the valve in bothdirections and free the engine from the limitation in-efiiciency'due to the lack of positive action of the valve in both directions. Furthermore, with my invention I produce an engine which is much more silent than engines in which the poppet valves are closed by spring action. Furthermore with the old type of construction a. clearance is provided between the valve .stem and the lifter to allow for the expansion in the valve and on account of this clearance, lost motion results and also a click follows every time that the single acting cam starts to lift the valve. In my type of construction, I eliminate the use of a spiral type valve stem spring commonly used for closing the valve and I I eliminate the clearance, all of which produces an engine that runs very quietly.

it-h reference to the cams shown in the drawings, I wish to refer to the section on the cam-shaft as the cam and the rolls. as l the engaging element.

I wish to further point out the importance of the cap, 28, Fig. 20. This cap may be used for varying the tension of the spring 27. It will be seen that this spring effects I the opening oft-he valve, 68. In the case of the exhaust valve it will be seen that as the pressure of the gas in the cylinder varies the pressure necessary to lift the valve varies. It will be seen that with a given tension on 1 the spring, 27, the cam may-not be able to lift the valve immediately -instead the cam will begin to move the lever, 60, away from the cam against the tension of the spring, 27. This will, of course, increase the tension in 1 the spring, 27, until the pressure of the spring is great enough to overcome the gas pressure on the head of the exhaust valve at which point the exhaust valvewill begin to open. It will be observed therefore that X regulating the tension of the spring, 27, the timing of the valve may therefore be regulated. In other words, the opening act will take place later with a light tension on the spring, 27, than with a heavy tension. It will also beseen that the sloping surfaces of the cam and cam engaging element is important in this connection. Therefore it will be seen that I have provided an engine in which the timing may be regulated while the engine is running, by regulating the cap, 28, and therethrough regulating the tension in the spring, 27.

What I claim as my invention is 1. In an internal combustion engine, a

crank-shaft, a cam operated by said shaft,

:1 poppet valve, a cam engaging element, the valve connected with said element by a link whereby the valve may be both opened and closed by said cam, and a spring for maintaining the cam engaging element pressed against the cam, and whereby in the event the valve does not respond, the cam may force said element out from the cam axis of rotation and avoid injury toany of the parts. I

2. In an internal combustion engine, a crank-shaft, a cam operated by said shaft, 21 poppet valve, a cam engaging element, the valve conneced with said element by a link whereby the valve may be both opened and closed by said cam, the link being flexiblewhereby the continued operation of the said cam engaging element by the cam after the valve strikes its seat, will flex the link and prevent injury to any of the parts, and a spring for maintaining the cam engaging element pressed against the cam, and whereby in the event the valve does not respond, the cam may force said element out from the cam axis of rotation and avoid injury to any of the parts.

In an internal combustion engine, a crank-shaft, a cam operated by said shaft, a poppet valve, a cam engaging element, the valve connected with said element by a link whereby the valve may be both opened and closed by said cam, and a spring for maintaining the cam engaging element pressed against the cam, and whereby in the event the valve does not respond, the cam may force said element out from the cam axis of rotation and avoid injury to any of the parts, said link including a universal joint.

4. In an internal combustion engine, a crank-shaft, a cam operated by said shaft, a poppet valve, a cam engaging element, the valve connected whereby the valve may be both opened and closed by said cam, the link being flexible whereby the continued operation of the said cam engaging element by the cam after the valve strikes its seat, will flexthe link and prevent injury to any of the parts, and a spring for maintaining the cam engaging with said'element by a link element pressed against the cam, and whereby in the event the valve does not respond, the cam may force said element out from the cam axis of rotation and avoid injury to any of the parts, said link including a universal joint.

5. In an internal combustion engine, a crank-shaft, a cam operated by said shaft, a poppet valve, a cam engaging element, the valve connected with said element by a link whereby the valve may be both opened and closed by said cam, and a spring for maintaining the cam engaging clement pressed against the cam, and whereby in the event the valve does not responchthe cam may force said element out from the cam axis of rotation and avoid injury to any of the parts, said .link having a shaft at right angles to the valve stem, an arm for said shaft projecting off therefrom and to the outer end of which arm the valve stem is attached.

6. In an internal combustion engine, a crank-shaft, a cam operated by said shaft, a poppet valve, a cam engaging element, the valve connected with said element by a link whereby the valve may be both opened and closed by said cam, the link being flexible whereby the continued operation of the said cam engaging element by the cam after the valve strikes its seat, will flex the link and prevent injury to any of the parts, and a spring for maintaining the cam engaging element pressed against the cam, and where by in the event the valve does not respond, the cam may force said element out from the cam axis of rotation and avoid injury to any of the parts, said link having a shaft at right angles to the valve stem, an arm for said shaft projecting off therefrom and to the outer end of which arm the valve stem is attached.

7. In an internal combustion engine, a crank-shaft, a cam operated by said shaft, a poppet valve, a cam engaging element, the valve connected with said element by a link whereby the valve may be both opened and closed by said cam, and a spring for maintaining the cam engaging element pressed against the cam, said link having a shaft at right angles to the valve stem, an arm for said shaft projecting off therefrom and to the outer end of which arm the valve stem is attached, said link also having a second arm projecting off from said shaft, the outer end of which arm terminates in the cam engaging element.

8. In an internal combustion engine, a crank-shaft, a cam operated by said shaft, a poppet valve, a, cam engaging element, the valve connected with said element by a link whereby the valve may be both opened and closed by said cam,the link being flexible whereby the continued operation of the said cam engaging element by the cam after the valve strikes its seat, will flex the link 7 and prevent injury to any of the parts, and a spring for maintaining the cam engaging element pressed against the cam, said link having a shaft at right angles to the valve stem, an arm for said shaft projecting off therefrom and to the outer end of which arm the valve stem is attached, said link also having a second arm projecting off from said shaft, the outer end of which arm terminates in the cam engaging element.

9. In an internal combustion engine, a crank-shaft, a cam operated by said shaft, a poppet valve, a cam engaging element, the valve connected with said element by a link whereby the closed by said cam, and a spr ng for maintaining the cam engaging element pressed against the cam, and whereby in the event the valve does not respond, the cam may force said element out from the eamaxis of rotation and avoid injury to any of the parts, said link having a shaft at right angles to the valve stem, an arm for said shaft projecting off therefrom and to the outer end of which arm the valve stem is attached, said link also having a second arm projecting off from said shaft, the outer end of which arm terminates in the cam engaging element.

10. In an internal combustlon engme, a

I crank-shaft, a cam operated by said shaft, a

poppet valve, a cam engaging element, the valve connected with said element by a link whereby the valve may be both opened and closed by said cam, the link being flexible whereby the continued operation of the said cam engaging element by'the cam after the valve strikes its seat, will flex the link and prevent injury to any of the parts, and a spring for maintaining the cam engaging element [pressed against the, cam, and whereby in the event the valve does not respond, the cam may force said element out from the cam axis of rotation and avoid injury to any of the parts, said link having a shaft at right angles to the valve stem, an arm for said shaft projecting off therefrom and to the outer end of which arm the valve stem is attached, said link also having a second arm projecting off from said shaft, the outer end.

of which arm terminates in the cam engage ing element.

11. In an internal combustion engine, a crank-shaft, a cam operated by said shaft, a poppet valve, a cam engaging element, the valve connected with said element by a link whereby the valve may be both opened and a spring pressing the element against the cam andithe engaging surfaces of the cam and of the cam engaging element sloping towards the axis of rotation of the cam whereby in the event of excessive strain along the link,'the cam engaging element compresses the said spring valve may be both opened and thereby relieving the strain between the elejury to the parts.

12. In an internal combustion engine, a crank-shaft, a cam operated by said shaft, a poppet valve, a cam engaging element, the valve connected with said element by a link whereby the valve may be both opened and closed by said cam, and a spring for maintaining the cam engaging element pressed against the cam, said link having a shaft at right angles to the valve stem, an arm for said shaft projecting off therefrom and to the outer end of which arm the valve stem is attached, said shaft journaled whereby the link oscillates about the longitudinal axis of the shaft responsive to the action of the cam. j

13. In an internal combustion engine, a crank-shaft, a cam operated by said shaft, a poppet valve, a cam engaging element, the valve connected with said element by a link whereby the valve ma be both opened and closed'by said cam, tie link being flexible whereby the continued operation of the said cam engaging element by the cam after the valve strikes its seat, will flex the link and prevent injury to any of the parts, and a spring for maintaining the cam engaging element pressed against the cam, said link having a shaft at right angles to the valve stem, an arm for said shaft projecting ofi' therefrom and to the outer end of which arm" the valve stem is attached, said shaft journaled whereby the link oscillates about the longitudinal axis of the shaft responsive to the action of the cam.

14. In an internal combustion engine, a crank-shaft, a cam operated by said shaft, a poppet valve, a cam engaging element, the

valve connected with said element by a link whereby the valve may be both opened and closed by said cam, and a spring for maintaining the cam engaging element pressed against-the cam, and whereby in the event the valve does not respond, the cam may force said element out from the cam axis of rotation and avoid injury to any of the parts, said link having a shaft at. right angles to the valve stem, an arm for said shaft projecting off therefrom and to the outer end of which arm the valve stem is attached, said shaftjournaled whereby the prevent injury to any of the parts, and a whereby in the event the valve does not respond, the cam may force said element out from the cam axis of rotation and avoid-injury to any of the parts, said link having a shaft at right angles to the valve stem, an arm for said shaft projecting off there- 'from and to the outer end of which arm the valve stem is attached, said shaft journaled whereby the link oscillates about the longitudinal axis of the shaft responsive to the action of the cam.

16. In an internal combustion engine, a crankshaft, a cam operated by said shaft, a poppet valve, a cam engaging element, the valve connected with said element by a link whereby the valve may be both opened and close-d by said cam, and a spring forkmaintaining the cam engaging element pressed against the cam, said link having a shaft at right angles to the valve stem, an arm for said shaft projecting off therefrom and to the outer end of which arm the valve stem is attached, said shaft journaled' whereby the link oscillates about the longitudinal axis of the shaft responsive to the action of the cam, said link operating to open the valve upon its oscillation in one direction and opera-ting to close the valve upon its oscillation in the opposite direction.

17 In an internal combustion engine, a crank-shaft, a cam operated by said shaft, a poppet valve, a cam engaging element, the valve connected with said element by a link whereby the valve may be both opened and closed by said cam, the link being flexible whereby the continued operation of the said cam engaging element by the cam after the valve strikes its seat, will flex the link and prevent injury to any of the parts, and

a'spring for maintaining the cam engaging element pressed against the cam, said link having a shaft at right angles to the valve stem, an arm for said shaft projecting off therefrom and to the outer end of which arm the valve stem is attached, said shaft journaled whereby the link oscillates about the longitudinal axis of the shaft responsive to the action of thewcam, said link operating to open the valve upon its oscillation in one direction and operating to close the valve upon its oscillation in the opposite direction.

18. In an internal combustion engine, a crank-shaft, a cam operated by said shaft, a poppet valve, a cam engaging element, the valve connected with said element by a link whereby the valve'may be both opened and closed by said cam, and a spring for maintaining the cam engaging element pressed against the cam, and whereby in the event the valve does notrespond, the cam may force said element out from the cam axis 19. In an internal combustion engine, a

crank-shaft, a cam operated by said shaft, a poppet valve, a cam engaging element, the valve connected with said element by a link whereby the valve may be both opened and closed by said earn, the link being flexible whereby the continued operation of the said cam engaging element by the cam after the valve strikes its seat, will flex the link and prevent injury to any of the parts, and a spring for maintaining the cam engaging element pressed against the cam, and whereby in the event the valve does not respond, the cam may force said element out from the cam axis of rotation and avoid injury to any of the parts, said link having a shaft at right angles to the valve stem, an arm for said shaft projecting off therefrom and to the outer end of which arm the valve stem is attached, said shaft journaled whereby the link oscillates about the longitudinal axis of the shaft responsive to the action of the cam, said link operating to open the valve upon its oscillation in one direction and operating to close the valve upon its oscillation in the opposite direction.

20. In an internal combustion engine, a crank shaft, a cam rotated by said shaft, a poppet valve, an element engaging said cam and operated thereby, the valve connected with said element whereby the valve may be operated by said cam, the cam surfaceengaged by said element sloping with respect to the axis "of rotation of the cam, and a spring for maintaining the cam engaging element pressed against the cam, and means to vary the tension of said spring.

21. In an internal combustion engine, a crank shaft, a cam rotated by said shaft, a poppet valve, an element engaging said cam and operated'thereby, the valve connected with said element whereby the valve may be operated by said cam, the cam surface engaged by said element sloping With respect to the axis of rotation of the cam, the engaging element being conical, the surface of the cone sloping with respect to the axis of rotation of the cam, and a spring for maintaining the cam engaging element pressed against the cam, and means to vary the tension of said spring.

22. In an internal combustion engine, a

. necting means between the valve and the said poppet valve, an element engaging said cam and operated thereby, the valve connected with said element whereby the valve may be operated bysaid cam,the cam surface engaged by said element sloping with respect to the axis of rotation of the cam, the engaging element being conical, the surface of the cone sloping with respect to the axis of rotation of the cam, the surface of the cone engaged by said cam pivoted to rotate, and a sprlng for maintaining the cam engaging element pressed against the cam, and means to vary the tension of said spring.

23. In an internal combustion engine, a crank shaft, a cam rotated by said shaft, a poppet valve, an element engaging'said cam and operated thereby, the valve connected with said element whereby the valve may be operated by said cam, the cam surfaceengaged by said element sloping with respect to the axis of rotation of the cam, the conelement consisting of a flexible link, whereby the cam may continue to move sa d element after the valve strikes its seat wlthout injuring said valve, and a spring for maintaining the cam engaging element pressed against the cam, and means to vary the tension of said spring. I

24. In an internal combustion engine, a crank shaft, a cam rotated by said shaft, a

I poppet valve, an element enga ing said cam' and operated thereby, the va ve connected I with said element whereby the valve may be operated by said 'cam, the cam surface engaged by said element slo ing with respect to the axis of rotation o the cam, and a spring for maintaining the cam engaging element pressed against the cam, and means to vary the tenslon of said spring wh1le the englne 1s running 25. In an internal combustion engine, a

valve and an operating cam, interconnecting mechanism between the cam and the valve for positively operating the valve from said cam both to open and close the valve, a yielding connection between the cam and the valve whereby the valve maybe held in any position while the cam continues to operatewithout the force of the cam damaging the valve.

26. In an internal combustion engine, a valve and an operating cam, interconnecting mechanism between the cam' and the valve for positively operating the valve from said cam both to open and close the valve, a yielding connection between the cam and the valve whereby the valve may be held in any position .while the cam continues to operatewith out the force of the cam damaging the valve,

and adjusting means for regulating the yielding connection to regulate the amount of force that the cam can deliver to the valve.

27. In an internal combustion engine, a valve and an operatin cam, interconnecting mechanism between t e cam and the valve for positively operatin the valve from said cam both to open and c ose the valve, a yielding connection between the cam and the valve whereby the valve may be held in any position while the cam continues to operate without the force of the cam damaging the valve, and adjusting means for regulating the yielding connection to regulate the amount of force that the cam can deliver to the valve whereby the timing of the valve may be varied as the pressure of the gas in the cylinder varies.

28. In an engine a cam, a valve, a cam engaging element, connecting means between said element and said valve, said valve and element so constructed that when the valve is free to move, the said element is restricted to one path of motion but when the valve is impeded at any point in its cycle of movement, said element is forced to follow a different path.

29. In an engine a cam, a valve, a cam engaging element, connecting means between said element and said valve,'said valve and element so constructed that when the valve is free to move, the said element is restricted to one path of motion but when the valve is impeded at any point in its cycle of movement, said element is forced to follow a different path a spring for retaining said element in said ing force of the valve is below a given magnitude but responsiQ e to said impeding force when it reaches the given magnitude to permit the element to move against the spring tension. i

firstpath as long as the imped- 30. In an internal combustion engine, a

sition while the cam continues to operate without the force of the cam damaging the valve, said construction involving a grooved cam in which said element operates, and a sloping side for said groove and for said element whereby said element may slide on said side in a direction having a component across the groove; i

In witness whereof, I have hereunto signed my name this 28 day ofl March, 1921.

ROBERT F. FISHER.

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