US1305397A - Valve-operating mechanism for engines - Google Patents

Description

C. S. MURDOCK. VALVE OPERATING MECHANISM FOR ENGINES. APPLICANON FILED JUNES, I913,

1,305,397. Pntentwl June 3, 1919.

I II 1' $1 ammo-L 6L5. Ma r510 CHESTER S. MURDOCK, OF BOONEVILLE, ARKANSAS.

VALVE-OPERATING MECHANISM FOR ENGINE.

Specification of Letters Patent.

Patented June 3, 1919.

Application filed June 8, 1918. Serial No. 238,071.

To all whom it may concern Be it known that I, Cnes'rnu S. MouoooK, a citizen of the United States, residing at Booneville, in the county of Logan and State of Arkansas, luive invented certain new and useful Improvements in Valve-Operatin Mechanisms for Engines, of which the f0 lowing a specification, reference being bad to the accompanying drawings.

This invention relates to improved valve operating mechanisms for engines, aml has for its primary object to provide means for actuating the valves of an inlcrnal combustion engine which is relatively s mple in its construction, practically silent in operation, and which may be utilized in conjunction with various types ,of multi-cylnnlered motor vehicle engines now in common use.

Itis also another important object of the invention to provide a valve operating means which will impart an initial rotar movemfl titothe valve before it is openec and tlfe by tarn'or grind the valve'upon its seat so that the, necessity of sc1)al'*tely regrinding the individual valves wil be obviated. y

Itis anothei' and; more particular object oi the invention tofprovide, in combination with the .ve moiin't d intlie cylinder head, a springyigldlngly urging the valve to its seat, angevechea camshaft and an adjustable bearing.clomebiagonnected tinthe valve stciQ and with which the cam portion on the shaft adapted to coact to first rotate the valve and then force thcsamc to its open position. 7 1 I With the above and other OlljCCtS in view, thcinvention consists in the improved construction, combination and relative arrangement of the several parts as will be hereinafter more fully desxrribed, subsequently claimed and illustrated in the accompanying drawing, in which similarneference characters designate corresponding parts throughout the several news, and where- 1n Figure 1 is a fragmentary side elevation, partly in. section, of a multi cyhndered nternal combustion engine equipped with my improved valve operating mechanism;

Fig. 2 is an enlarged vertical section taken on the line 22 of Fig. 1;

Fig. 3 is a section taken on the line 3%% of Fig. 2; and

Fig. 4 is an enlarged detail elevation of the cam shaft and the adjustable tappet member with which the cam engages.

Referring in detail to the drawing, 5 designates the engine cylinders in which the usual pistons are mounted to reciprocate, said pistons being actuated from the crank shaft 6. It will, of course, be understood that the engine may be provided with any desired number of cylinders. These cylinders are provided with heads 7 cast en-bloc and secured upon the upper ends of the cylinders in any approved manner. In the heads 7, an intake and exhaust valve 8 for each of the engine cylinders are mounted. Each of these valves is fixed pen the lower end of a stem or rod 9 whirl extends up wardly through a guide 10 centrally formed upon the base wall of the chamber 11 of the cylinder head. Exteriorly of this chamber 11 at each side thereof, the cylinder head is provided with longitudinally extending water chambers 12 in communication with each other at one of their ends and having inlet and outlet connections respectively at their opposite ends. In Fig. 2 of the drawing, I have shown a manifold lii leading to the port which is normally closed by the valve 8. It will he understood that the cylinder head is equipped with an intake and exhaust manifold for the engine cylinders.

Spaced bars 14 extend transversely across the top of the chamber 11, each of said bars being centrally provided with an openin to receive the iuteriorly threaded shank 1% of a tappet member 16, which is in the form of a metal disk integral with. one end; of said shank. The shanks 15 are adjustably engaged upon the threaded upper ends of the respective valve stems 9. Eiich bar 14 is preferably formed with a guide bearing 17 for the shank 15.

To each valve rod or stem 9, below the bar 14, a metal disk or collar 18 is secured. A coil spring 20 surrounds the valve rod guide 10 and bearsat its upper end against the collar 1b. The lower end of this spring has, an annulus -31 lixcd thereto, which is provided with a raceway to receive the anti friction bearing balls '32. which are also on gaged in a similar raceway at the base f the guide 10.

Above the transverse bars 14, a longitudinally extending shaft 23 is journalcd at its ends in suitable hearings on the cylinder head 7. This shaft provided at spaced points with the cams 24 corresponding in number to the number of valves 8. These cams may be either in the form of off-set cranks or separate arms fixed upon the shaft 23. The ends of the cams are adapted for engagen'ient upon the respective tappet disks 16, and the end edge of each cam is obliquely inclined as indicated at 25, or in other words, the cam at one side is lower than at its oppo- Sito side so that the lower side of the cam will first contact with the surface ol' thr disk 16 at one side of its axis. The beveled purtion 25 extends only a slight distance along the periphery of the cam 24 and the remaining portion of the cam is flat. it is to be further noted that the transverse center of the cam occupies the same plane the axial center of the disk 16 and the coacting stem 9. By this construction and arrangement it will be noted that the beveled portion 5 will first contact with the disk 16 at a point to one side of its axial center and which will result in a slight rotation of said disk. VV hcn the flat portion of the cam contacts with the axial portion of the disk, a direct downward thrust of the rod will result without any rotary action. It will therefore be apparent that in the rotation of the shaft 22, there will first he a rotativc n'iovement of the rod 9 and valve 8 before the cam exerts sutlicient hearing pressure on the disk 16 to overcome the action of the spring 20 and move the rod 9 longitudinally, whereby the valve is displaced from its seat. In this manner, each valve 8 will be ground upon its seat when it is opened in the operation of the engine, and it is not necessary to regrind the individual valves at frequent intervals is now the universal custom. By subjecting the disk 8 only to a slight relative movement, the Wear upon the valve 8 and its coacting seat will be materially reduced so that the life of the same will be greatly prolonged.

A removable cover or housing 26 ineloses the. cam shaft 23 and the ta'ppet members, and to one end of this housing the upper end of a vertically disposed housing 26 is suit ably secured, the lower end of said latter housing being fixed to the crank case. This housing 26 inelosed an endless chain 27 eugaged upon a sprocket 28 fixed on one end of the cam shaft 23, said chain also extending around a sprocket 29 on one end of the crankshaft 6. One stretch of said chain is operativcly engaged with a sprocket pinion on the [an shall 30. Any suitable means maybe provided for tightening or taking up the slack in the chain 27.

The end of the cylinder head, to which the housing 26 is secured, provided immedi ately below the cam shaft 23 with one or more openings indicated at iii. The corrcsponding end oi the crank case above the shalt l3 opens into said housing. Thus, as the oil contained in the bottom of the crank case is violently agitated by the cranks on the shaft (3 in the operation of the engine, the oil vapor will rise through the housing 26' and pass through the openings 31 into the housing 26. At the opposite end of the housing 26, and at the top thereof, a breather opening 32 is provided, through which the vapor is exhausted to the utllllm'plltl'ii. in its passage through the housing 26, the oil vapor collects upon the shaft 3;), so that the hearings for said shalt are lubricated and the fillillllim lb of the vertically movable tap pct members are likewise lubricated by the oil vapor so that they will move freely and without friction through the bearings 17.

From the foregoing description, takcn in connection with the accompanying drawing, the construction, manner of operation and several advantages of the invention will be clearly and fully understood. By providing the overhead cam shaft for the operation of h the valves, the mechanism is greatly simplified, as the use of i'iunicrous rocker arms and push rods is thereby avoided. By roviding a valve operating means which automatically grinds the valves and the valve seats, con sidel'able trouble and expense incident to the separate rcgrindiug oi the valves is avoided. The device as a whole consists of relatively few simply constructed parts and can be readily incorporated in various types of internal combustion engines now commonly used for the propulsion of motor vehicles at relatively small cost. The mechanism is also durable in its construction, positive and reliable in operation, and not liable to get out of order.

While I. have herein shown and described the preferred construction and arrangement of the various elements, it is to be understood that the device is susceptible of considerable modification therein, and I therefore reserve the privilege of adoptin all such legitimate changes its may be fairy embodied Within the spirit and scope of the invention as claimed.

I claim I In combination with a valve and its stem, and means for constantly urging the valve to its seat, a disk secured to the outer end of the stem, and a rotatable cam coacting with the disk, a portion of the periphery of the cam being transversely beveled, the remain ing portions thereof being fiat, the beveled portion of the cam engaging the disk at one side of its axial center to impart slight rotary movement to the disk'and to the valve, the flat periphery of the cam contacting with the axial center of the disk for imposing a direct thrust upon the stem.

C. S. MURDOCK.

Witnesses BOLIN Cnmnn, J. W. H. MARTIN.

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