US2209496A - Automatic compression control for engines - Google Patents

Description

J 1940- R. D. WATSON 2.209,496

AUTOMATIC COMPRESSION CONTROL FOR ENGINES Filed Feb. 15, 1939 45] 1eets-Sheet l July so, 1940.

R. D. WATSON AUTOMATIC COMPRESSION CONTROL FOR ENGINES Filed-Feb. 15. 1959 KICHAEO fl VVArso/v,

4 Sheets-Sheet 2 July30,1940- R. ,nfwATsofi 2209,496

- I AUTOMATIC COMPRESSION CONTROL FOR ENGINES Filed Feb. 15,- 1959 4 Sheets-Shet 4 gwu /l vm 110 I R/CHAQD 0. T WWso/v,

I Patented July 30, 1940 me sTATss PATENT oFFics Richard D. was, Ang'eles, assignor v of one-half to George Yates, Glendale, Calif.

Application February 15, 1939, Serial No. 256,497

21 Claims. (01.123-182) This invention relates to mechanisms for controlling the compression of'engines, and particularly to that type of mechanism which relieves the engine of compression to permit a starting device to impart momentum to the engine parts under relatively light loads, and which especially of the internal combustion type, to facilitate their starting.

It is another object of the invention to provide a device capable offdiscontinuing the operation of an engine through control of its compression.

A further object of the invention is to provide a device capable of controlling engine compres- 2o sion from a relatively remote point.

Still another object of the invention contemplates a safety device which will automatically discontinue engine operation in the event of defects arising in, or failure of, the lubricating sys- Another object or the invention is'to prevent operation of an engine having a defective lubrieating system; and to prevent its starting until the defect has been r'emedied.-

Another object of the invention is to safeguard "an internal combustion engine from i possible -damage due to overheating.

A further object of the invention is to provide means for discontinuing, engine operation upon excessive heating or complete failure of the cooling fluid.-

Another object of the invention is the provision of an automatic system for substantially simultaneously controlling the compression inall of the cylinders of an" engine. -A further object of the invention is to provide means for governing the compression in each cylinder of a multiple cylinder engine by means controllable from acommon source This invention possesses many other advantages and hasother objects which maybe made more easily apparent from a consideration of several embodiments of the invention. For this purpose there are shown a number of forms in the drawings accompanying and forming part of the present specification. These forms will now be described in detail, illustrating the general principles of the invention; but it is to be under-, stood that this detailed description is not to be taken in a limiting sense, since the scope of the I invention isbest defined by the appended claims. Referring to the drawings: Figure 1 is a diagrammatic view illustrating a system of compression control with parts shown in compression releasing position. Figure 2 is a view similar to Figure 1 showing the partsJna position permitting normal engine operation.

Figure 3 is a section through a modified constructional arrangement of the servo-motor and 10 v valve control embodied in the system'shown in Figure 1.

Figure 4 is a transverse section taken as indi-' cated by the line 4-4 of Figure 3.

Figure 5 is a diagrammatic view illustrating 1|,

the system of Figure 1 as applied to a multiple cylinder engine, certain parts being shown in compression releasing position, and

Figure 6 is a view similar to Figure 5, with parts being shown in,engineoperating position. go The system disclosed in Figures 1 and 2 of the drawings includes the usual cylinder Iii of an" engine, preferably of the internal combustion type,ihaving inlet and outlet valves, only the out let valve It being shown in the drawings. The '25 valves are operated from a cam shaft through the instrumentality of cams l6 and i1 normally engageable with valve tappets I8 and i9 producing reciprocation of push rods and 2|, which in turn oscillate rocker arms in a usual and well-known manner, the outlet valve rocker arm 22 being the only one shown in the'drawing.

The cam shaft I5 is driven from the engine crank I shaft (not shown), and is journaled in bearings 24 and 2B whichare supplied with-lubricant by a means of a pump 26 having communication with the bearings through the conduits 21. This pumpis driven from the engine cam shaft l5 through suitable mechanical means such as the chain 28 connecting sprockets 29 and 30 carried onthe a respective cam and pump shafts, and pumps lubricantfrom the usual engine crank case (not shown) through the strainer'3l and intake pipe 32 and exhausting it into the conduitsiz'i for lubricating various parts of the engine mecha- Engines having a relatively high compression ratio can be started against this high compression pressure only by imposing a very heavyload on the battery and starting motor. This is par- 5Q ticularly true in connection'wlth Diesel engines,

which have compression ratios of as'much as 18 to 1. The present invention seeks to provide a systemvand mechanism obviating the need for starting the engine against this high compres- 5 l the open valve.

sion load by relieving the engine of its compression while momentum is imparted to the engine by a starting device operating against a relative light load. After sufficient kinetic energy has been stored in the starting motor and the engine parts, the engine compression can be re-established in order to produce its self-operation.

In the specific example disclosed in Figures 1 and 2, an element is interposed in one of the valve actuating means to prevent the valve from closing when its operating cam is in valve closing position. This element is constituted by a lever finger or arm having an end 36 cooperable with a supplementary cam 31 fixed to the cam shaft I5. This cam 31 is preferably small enough to fall within the base circle of the cam l6 in order to have no effect upon the valve tappet l8 until the lever finger 35 has been interposed between the tappet l8 and the supplementary cam 31. It will be noted that the supplementary cam lobe extends substantially oppositely to the tappet lifting portions of the main cam 16 to prevent complete lowering of the tappet I8 when the lever finger 35 is interposed between the supplementary cam 31 and the tappet I8, and consequently, prevents closing of the associated valve ll. Whenever the lever finger 35 is in such interposed position the associated valve I i will be prevented from closing completely since the cam contacting surface pre-' sented by the finger end 36 extends beyond the base circle of the main cam I6, and a medium within the cylinder II] will be incapable of being compressed due to its ability to escape through Removal of the lever finger 35 from engagement with the supplementary cam 31 will permit normal operation of the valve mechanism and the creation of the usual compression pressure within the cylinder 10.

The particular position occupied by the lever finger 35 with respect to e supplementary cam 31 is determined by conditions of operation of the internal combustion engine. So long as the engine is rotating properly, the lever finger 35 will be maintained out of the path of movement of the supplementary cam 31 and free it. from any restraining movement upon the valve tappet l8.

But in the event that the engine is stationary, or certain undesirable conditions arise in connection with its operation, the lever 35 will be moved longitudinally along the cam shaft l5 into radial contact with the supplementary cam 31.

The aforementioned functions are achieved in the instant case by mounting the lever 35. for oscillation upon a shaft 40 having one end 400. forming a piston slideable within a fiuid cylinder 42. Fluid under pressure can be conveyed from the lubricating conduit lines 21, or from one of the engine bearings, by conducting it through the branch line 43, communicating with an end of the fluid cylinder 42. It will therefore be seen that the rotation of the crankshaft, cam shaft, or other rotatable parts of the engine will operate the lubricating pump 26 to force fluidv to the various bearings and other parts of the engine, and also exert a pressure upon the fiuid within the cylinder 42 to move the piston 40a therein. This movement will be communicated to the lever 35 since it is restrained from axial movement with respect to the piston shaft 40 by the oppositely disposed collars 45 and 46 pinned or otherwise suitably secured to the shaft 40. In the event that the piston40a moves suiiiciently, the lever 35 will be disengaged from the supplementary cam 31 and permit normal operation of the associated valve mechanism. However, the shaft 4|) of the shaft 40 piloted within this cylinder. The

compression of the spring can be determined by means of the adjusting plug 52 threaded intothe outer end of the cylinder 5|.

The operation of the parts so far described can now be understood. A stationary condition of the engine results in the lack of pressure in the lubricating system in view of the fact that the pump 26 is not being driven. The helical spring can therefore urge the lever finger 35 into a position in which its outer end .36 will engage with both the supplementary cam 31 and the valve tappet i8, preventing closing of the associated valve II in the manner aforementioned. If the engine is cranked by a suitable starting device, the pump 26 will be rotated and pressure built up in the fluid system. The more rapid the motion of the engine parts, the greater the speed of the pump and also the pressure generated by it. A condition is eventually reached wherein the engine parts are rotating at a sufficient speed to overcome any starting compression that can be built up in the cylinder 10. When this condition is developed, sufiicient pressure will also be produced in the lubricating system and in the fluid cylinder 42 to force the shaft 40 and its piston 40a outwardly against the action of the spring 50 and free the lever from contact with the supplementary cam 31. The compression then obtained in the cylinder in will be sufiicient to ignite injected fuel (in the case of.a Diesel engine) or ignition of compressed fuel (in the case of an engine operated on the Otto cycle). So long as the engine is operating under its own power, the lubricating pump 26 will generate sufiicient pres sure to hold the shaft 40 and its piston 40a in proper position against the action of the spring 50 and maintain the lever finger 35 out of compression releasing position with respect to the supplementary cam 31 and the valve tappet l3. But upon stopping of the engine or loss of lubricating pressure in any other manner the spring 50 can reestablish radial engagement between the supplementary cam 31 and lever finger 35 and prevent further operation of the engine by continued relieving of its compression. The lever finger 35 is held in'proper radial contact with the supplementary cam 31 by means of the helical spring 55 connected to the lever extension 56 and to some stationary member.

Since the system described is dependent upon the pressure of the lubricating fluid for permitting self-operation of the engine, it will be apparent that loss of this pressure will produce stopping of the engine by relieving its compression through the interposition of the lever finger 35 between the supplementary cam 31 and the valve tappet l8. Accordingly, should the pump fail, or leakage occur in the lubricant system, or the lubricant supply in the crank case sump become exhausted, the pressure in the fluid cylinder will drop and the engine stopped before any damage This can be accomplished by instem 64, or a suitable handle fixed thereto (Figures and 6), which action will permit the lubricating fluid to escape to the engine sump (not shown) through the valve inlet and outlet conduits I1 and 68, and thereby permit the spring 50 to position the lever finger 35 in radial contact with the supplementary cam 31 to relieve the engine of compression by preventing closing I of the valve The pressure relief valve 60 can also be operated in other ways, as by connecting a suitable remotely controlledsolenoid with its stem (not shown). It can also be controlled remotely in dependance upon the operating temperature of the engine, being cause to open in the event of excessive heating of engine cooling elements, such as cooling water. In the specific example shown in Figure 1, a thermostat bulb 10 is connected in the water cooling jacket 1| of the cylinder head 12, with a line 13 leading from the bulb 10 to an expansible bellows 16 contained within a housing 15. One end of 'the bellows is fixed to the housing in such a manneras to form a leakproof joint therewith, and the other end operates against a push rod 16 .slideable in a guide sleeve 11 fixed to an intermediate partition 18 in the housing 15. Expansion of the fluid in the thermostat bulb 10 and its communicating line 13 upon increase in the temperature of the cooling water in the jacket 1|, will tend to. force the push rod 18 downwardly against the action of a spring 19 encircling the rod 1% and engage'able with a head 80 secured to its upper end and also with a nut 8| adjustably threaded on the guide sleeve. The push rod 16 extendsvthrough the housing and .is operatively connected with a lever'82 fulcrurned on a suitable stationary supporting bracket 83.

The connection may be in the form of a slot 84 in one end of the lever receiving a looped portion 85 ofthe push rod 16 to provide a lost motion therebetween. The other end of the lever is connected with the valve stem 64 through the pivotal connection 86.

As the temperatureincreases in the cylinder head water jacket 1|, the fluid in the thermostat bulb 10 will expand, distending the bellows 14' downwardly and producing corresponding movement of the push rod 16 against the action of thespring 19. No motion will be imparted to the lever 82 and relief valve stem 66 until the push rod'16 engages with the bottom of the lever slot 86. Such engagement will only occur upon an excessive rise in the jacket cooling water temperature, which condition will effect a rocking of the lever 82 on its fulcrum 82a and a raising of valvehead 63 from its seat 62, which permits venting of the lubricant to the crank case sump through the line 68, and decompression of the engine by movement of the lever finger-3S into proper cam engaging position un- I der the influence of the spring 50.

In efiect, the fluid cylinder and piston device 40, 42, etc., and the return spring mechanism 60,

. it, etc. constitute a servo-motor operable in ac- The limits of travel of the lever 35 and the piston cordancewith certain definite engine conditions.

shaft 40 can be determined by utilizing the restraining collars "and 46 as stops abutting against the ends of the respective piston and spring cylinders 42 and SI. The range of movement *is chosen so that abutting of the collar 46' against the fluid cylinder 42 occurs upon complete engagement of the lever finger 35 with the supplementary cam 31, while abutting of the other collar 45 against the end of the spring cylinder 5| occurs upon complete disengagement of the lever 35 from the cam 31, as shown in Figure 2.

structural organization. In this figure, the cam shaft |5a is'rotatable in suitable bearings 24a and .25a supplied with lubricant through the ducts 21a and 21b. The servo-motor S is shown attached directly to parts of the engine housing 90 by bolts ill, the fluid pressure cylinder 42a communicating with the cam shaft bearing a through the fluid reservoir 42b contained within the servo-motor housing, and the aligned ducts 9| and 92 in said housing and the engine housing 90. The shaft a carrying the lever 35a and confining collar stops a and 46a heretofore described, includes a piston portion 6% within the cylinder 42a and-another portion 400 slideable within a bore 5|a provided in the end of the servo-motor housing. This bore is closed by a terminal cap 95 secured to the servo-motor housing by screws 96, the cap being provided with a recess 91 receiving a helical spring 98 also confined within a recess $9 in the end of the shaft 40a. One end of the spring 98 abuts against a plug 52a threaded into the cap 95, whereby the spring. tension can be adjusted. The lever finger 35a is maintained against the cam shaft |5a or against the supplementary cam 31a by means of the spring ||l| attached to the lever extension 56a and to an anchor screw I02 threadedly secured in the servo-motor housing.

The operation of the parts shown in the modification of Figures 3 and 4 is the same as that described inconnection with'Figures l and '2. However, the relief valve a is formed integrally with the servo-motor housing, its body 6|a extending from the housing and its inlet 61a opening into the reservoir or manifold 42b. The valve outlet passage or conduit 68a extends through the servo-motor housing, communicating with the crank case sump. The-valve head 63a, stem 64a, encircling spring 86a, and threaded plug 65a are substantially the same as described in connection with Figures 1 and 2 but the valve is adapted to be operated manually through the handle I05 instead of the automatic means shown and described in connection with Figures 1 and 2.

As shown in Figures 5 and 6, the system is also applicable'for use in connection with multiple cylinder engines, efiectively controlling com-' pression' in each and every one of the engine cylinders. The lubricating pump I I0, relief valve strainer H2, etc., occupy the same relative positions as described in connection with Figures 1 and 2. The cam shaft H3 is disclosed as being provided with a plurality of pairs of cams, each pair consisting of a cam lid for controlling an inlet valve and a cam M5 for controlling an the springs I41.

the same relationship with respect to the exhaust cam as described in connection with Figures 1 and 2. Similarly, a lever finger I26 can be moved into radial contact with each supplementary cam- I to control the engine compression. Each lever is oscillatably mounted on a shaft I21 slideable in the guides I28 and I29 suitably secured to the engine or some convenient stationary support. As described above in connection with Figures 1 and 2, collars I30 and I3I are fixed to each shaft I21 and are positioned on opposite sides of the lever finger I26 to prevent its axial movement with respect to the slideable shaft I21 and also to act as stops, limiting the extent of travel of the shaft I21 in its guides I26 and I29. Thus, when the collar I3I is abutting against the guide I29, the lever finger is in contact with the supplementary cam I25, functioning to relieve the cylinder from compression. Axial movement of the shaft I21 to cause abutting of the collar I30 against the guide I28, insures movement of the lever finger out of contact with the supplementary cam and permits compression of whatever medium is in the engine cylinder.

The lever fingers I26, I26 are mounted for independent oscillation to permit their operation in conjunction with the supplementary cams I25, I25, which are angularly'displaced on the cam shaft with respect to one another in view of the usual angular displacement of the exhaust cams relative to onewanother. For this reason, a separate shaft I21 is provided for oscillatably mounting each of the lever fingers. However,

the axial positions of the levers with respect to the supplementary cams are governed by a common servo-motor I operable substantially simultaneously upon all of the slideable shafts. This servo-motor includes a cylilnder I36 in communication with the engine lubricating system, there being a piston I39 slideable within the cylinder I36 and a piston rod I 40 connected thereto and extending through the cylinder for reciprocation in the guideways I28, I29. A yoke I4I for each cylinder is pinned or otherwise suitably secured to the extended piston rod I40, each yoke being operable upon a flanged collar I42 slideable upon the shaft 521. Each shaft I21 carries collars I45 and I 450. pinned to its ends.- A spring I46 encircling the rod I 21 between one of the guides I26 and a collar I45a, serving to urge the lever finger I26 into radial contacting position with the supplementary cam I25. A spring I41 of much greater compressive strength than the spring I46 encircles the shaft I21 between the other guide I-26 and the flanged collar I42, tending to slide this collar along the shaft I21 into contact with the fixed collar I45, and thereafter slide the shaft I21 in its guideways I28, I29, to move the lever finger I26 out of contact with the supplementary cam I25.

When lubricating pressure is lacking system, a spring I50 encircling the piston rod I40 within the cylinder I36 will move the piston I39 towardthe inlet end of the cylinder and correspondingly slide the flanged collars I42 along their respective rods I21 against the action of This relieves the effect of'these springs upon the slideable rods I21 and the lever fingers I26, permitting the springs I46 of lesser compression to move the rods I21 and position the fingers I26 into radial contact with the supplementary cams I25, thereby relieving all of the cylinders of compression. Upon the creation ofsuflicient pressure in the lubricating system the piston I39 will be moved in the cylinder I36 in the against the action of its engaging spring I50 and will move the yokes I4I away from the,

flanged portions of the collars I42, allowing the springs I41 of greater compressive strength to force the flanged elements I42 against the collars I45 on the shafts and move the lever fingers I26 out of radial contact with the supplementary cams I25, permitting the establishment of compression in all of the engine cylinders and its susequent self-operation.

It will be appreciated that the multiple compression relieving system can also have the same safety and control features described in connection with the single cylinder system of Figures 1 and 2.

I claimz l. A system for controlling thecompression of engines having valve actuating mechanism including means adapted to be interposed in said valve actuating mechanism for preventing clos ing of a valve actuated thereby, means tending to interpose said first means, and means controllable by theengine operation for maintaining said first-means in non-interposed position.

2. A system for controlling the compression of engines having valve actuating mechanism ineluding means adapted to be interposed in said movement of said actuating means, means oper- I able by said engine for imparting pressure to a fluid, and means for conducting said fluid under pressure to said pressure responsive means, whereby said interposed means is movable from the path of movement of said valve actuating means. 4. A system for controlling the compression of engines having valve actuating means including means adapted to be interposed in said means for preventing closing of a valve adapted to be actuated thereby resilient means for interposing said means, fiuid pressure responsive means for positioning said interposed -means out of the path of movement of said actuating means, means operable by said engine for lubricating engine parts by fluid under pressure, and means for conducting said fluid under pressure to said pressure responsive means, whereby said interposed means is movable from the path of movement of said valve actuating means. 5. A system for controlling the compression 0 engines having valve actuating means including means adapted to be interposed in said means for preventing closing of a valve adapted to be actuated thereby, means responsive to motion of engine parts for shifting said interposed means from the path of movement of said actuating means, and control means for determining the position of said interposed means with respect to 2,209,49e for preventing closing of a valve adapted tobe actuated thereby resilient means for interposing said means, fluid pressure responsive means for positioning said interposed means out of the path of movement of said aetuatingmeans, means operable bysaid engine for imparting pressure to-a fluid, means for conducting said fluid under pressure to said pressure responsive means, whereby said interposed means is movable from thepath of movement of said valve actuating means, and valve means for decreasing the pressure of said fluid to permit positioning of said interposed means in the path of movement of said valve actuating means.

'7. A system'for controlling the compression of engines having valve actuating means including 'means adapted to be interposedin said means for relieving said engine of compression by preengines having valve actuating means including means adapted to be interposedin said means for preventing closing of a valve adapted to be actuated thereby, fluid pressure responsive means for positioning said interposed means in and out of the path of movement of said actuating means,

means operable by said engine for imparting pres-. sure to a fluid, means for conducting said fluid under pressure to said pressure responsivemeans,

whereby said interposed means is movable from the path of movement of said valve actuating means, valve means for decreasing the pressure of said fluid to permit positioning of said interposed means inthe path of movement of said valve actuating, means, and means responsive to a characteristic of an engine cooling means for operating said valve means.

9. A system for controlling the compression of an-engine having a plurality of cylinders, valves cooperable with said cylinders for controlling engine operation, individual means for actuating a valve for each cylinder, separate means adapted to be interposed in said individual means for relieving its associated cylinder of compression by preventing closing of its valve, and means responsive to motion of engine parts for shifting said interposed means from the path of movement of said actuating means.

10. A systemfor controlling the operation of an engine having a cylinder and valve cooperable therewith for controlling the compression therein, valve operating means comprising cam means, means operativeiy connecting said cam means with said Valve, and means adapted to I means for opposing the action of said fluid under be interposed between said cam means and connecting means for preventing closing of said valve regardless of the position of said cam means.

11. A system for controlling the operation of an engine having rotatable means, a cylinder and cooperable valve for controlling the compression in said cylinder, valve operating means comprising cam means and means operatively connecting said cam means with said valve, means adapted to be interposed between said cam means and connecting means for preventing closing of said valve regardless of the position of said cam means, and means responsive to 5 rotation of said rotatable means for shifting said interposed means to permit closing of said valve.

12. A system for controlling the operation of an engine having rotatable means, a cylinder and cooperable valve for controlling the compression in said cylinder,valve actuating means comprising a cam shaft carrying a cam, means operatively connecting said cam with said valve, means adapted to be vinterposedbetween said cam shaft and connecting means for preventing closing of said valve regardless of the position of said cam, fluid pressure responsive means for shifting said interposedmeans to permit closingof said valve, means responsive to rotation of said rotatable means for imparting pressure to a fluid, and means-for conducting said fluid under to be interposed between saidcam means and connecting means for preventing closing of said valve regardlessof the position of said cam means,

and servo-motor means responsive to rotation of said rotatable means for shifting said interposed means longitudinally 'of said cam means to permit closing of said valve.

14. A system for controlling the operation of an engine having a cylinder and cooperable valve for controlling the pressure in said cylinder, valve operating means comprising cam means and means operatively connecting said cam means with said valve, lever means adapted to be interposed between said cam means and connecting means for preventing closing of said valve regardless of the position of said cam means, and servo-motor means mounting said lever means for oscillation'and adapted to shift the same longitudinally of said cam means to permit closing of said valve.

15. A system for controlling the operation of an engine having a cylinder and cooperable valve for controlling the pressure in said cylinder, a cam shaft carrying cam means, means operativeiy connecting said cam means with said valve, lever means adapted to be interposed between said cam means and connecting means for pre-. venting closing of said valve regardless. of the position of said cam means, fluid pressure responsive means mounting said lever means for oscillation, means for imparting pressure to a fluid, and means for conducting'said fluid under pressure to said pressure responsive means to shift said lever means longitudinally of said cam shaft away from said camv means to permit closing of said valve. 1

16. A system as defined in claim 15, including pressure tending to maintain said lever means in interposed position.

17. A system for controlling the operation oi an engine having a cylinder and cooperable valve for controlling the pressure in said cylinder, a

position of said cam means, means for imparting pressure to a fluid, and means for conducting for shifting said piston and lever means longitudinally of said cam shaft and away from said cam means to permit closing of said valve.

18. A system for controlling the operation of an engine having rotatable means, a cylinder and cooperable valve for controlling the compression in said cylinder, a cam shaft carrying cam means, means operatively connecting said cam means with said valve, a fluid cylinder, a piston slideable in said fluid cylinder,- lever means oscillatably mounted on said piston and-adapted to be interposed between said cam means and connecting means for preventing closing of said valve regardless of the position ofsaid cam means, a pump driven by said rotatable means for imparting pressure to a lubricant, means for conducting said fluid from said pump to said fluid cylinder for shifting said piston and lever means longitudinally of said cam shaft and away from said cam means to permit closing of said valve.

19. A system as defined inclaim 18, including means for opposing movement of said piston under the action of said fluid and urging said lever means to interposed position.

20. A system for controlling the compression of an engine having a plurality of cylinders, valves cooperable with said cylinder for controlling engine operation, individual means for actuating a valve for each cylinder, a camshaft said fluid under pressure to said fluid cylinder carrying a plurality of cam means angularly disposed with respect to each other, a lever adapted to be interposed between each of said cam means and said individual means for relieving its associated cylinder of compression by preventing closing of its valve, a separate shaft oscillatably supporting a lever ,for movement longitudinally of said cam shaft to and from its interposed position, and common means for simultaneously shifting said shafts longitudinally.

21. A system for controlling the compression of an engine having a plurality of cylinders, valves cooperable with said cylinders for controlling engine operation, individual means for actuating a valve for each cylinder, a cam shaft carrying a plurality of cam means angularly disposed with respect to each other, a lever adapted to be interposed between each of said cam means and said individual meansforrelieving its asso- RICHARD D. WATSON.- 30

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