US1927020A - Automatic take-up for engine valve mechanisms - Google Patents

Description

Sept, 19, c 5 BROWN AUTOMATIC TAKE-UP FOR ENGINE VALVE MECHANISMS Filed Sept. 50, 1951 ATTORNEY5,

Patented Sept. 19, 1933 PATENT OFFICE AUTOMATIC TAKE-.UP FOR ENGINE VALVE MECHANISMS Charles S Brown, Syracuse, N. Y.

Application'September 30, 1931 I 'SerialN0.566,074

2 Claims. (01. 129-00) This invention relates to valve operating mechanisms, particularly, poppet valve mechanism where clearances in the parts of the mechanism vary under different conditions; for instance,

valve mechanisms for internal combustion engines where the clearances vary as the engine This invention comprises coacting means between the lifter 8 and the lift rod '7 for automatically taking up any lost motion by shifting the lift rod '7 endwise, or axially, relative to the lifter, this additional shifting movement being effected 60 by a relative turning of the lifter 8 and the rod heats and the cylinders elongate. The invention '7. In the illustrated embodiment of my invention,

has for its object a particularly simple and efficient means for automatically taking up lost motion or clearances.

The invention consists in the novel features and in the combinations and constructions hereinafter set forth and claimed.

In describing this invention, reference is had 5 to the accompanying drawing in which like characters designate corresponding parts in all the views.

Figure 1 is a fragmentary View of an internal combustion engine showing this valve lifter mech- 5120 anism.

Figure 2 is a sectional view on line 22, Figure 1.

Figure 3 is a detail view illustrating compensating action of the lifter on the lift rod by the T turning of the lifter relatively to the rod.

I have here shown this valve mechanism applied to an internal combustion engine, although it may be used in other situations. The valve mechanism shown is of the overhead type.

1 designates the cylinder of an internal combustion engine; 2, the head thereof; 3, the crank case in which the crank shaft and cam shaft are located.

4 designates one of the valves in the head, this being a poppet valve having an upwardly extending stem 5, the valve being held against its seat by the usual spring 6.

The valve mechanism includes two members,

one a lift rod 7 and the other a lifter 8 which thrusts against the end of the rod '7, the lifter and the rod being movable axially. The lifter is actuated by the usual cam 9 on the cam shaft and the motion of the lift rod is transmitted to the valve stem in any suitable manner.

As the valve mechanism here shown is for an engine having overhead valves, the lift rod coacts with one end of a rocker arm 10 pivoted at 11 between its ends, the other end of the rocker arm coacting with the end of the valve'stem 5. 5 It is essential for most efficient valve operation and to avoid tappet noises, that the clearances or lost motion be taken up at all times and under all conditions between the end of the valve stem and the rocker arm and between the rocker arm 5 and the lift rod.

means is provided for turning the lifter 8 relative to the lift rod '7 to take up lost motion, if there is lost motion, and the turning movement is transferred through cams to the lift rod to give the added lifting movement to the lift rod '7.

In the illustrated embodiment of my invention, the abutting ends of the lift rod 7 and the lifter 8 are provided with cam or inclined plane faces 12 and. 13, which upon turning of the lifter in one direction boosts up the lift rod 7 and, as here shown, a pair of such faces is provided on the end of each of the members 7 and 8, although any number of such faces may be provided. The lifter is provided in its end with a shallow socket having flat inclined plane faces diverging downwardly and outwardly from a diametric line of the lifter 7; the apex of said faces being rounding; and the upper end of the lifter is provided with 3' complemental faces.

The lifter is guided in the usual guide bushing 14 secured to the top of the crank case at one side of the cylinders, the bushing'enclosing the abutting ends of the lift rod 7 and the'lifter 8. 5 The lift rod fits the bushing more snugly than the lifter 8 in order that the lift rod 7 may be held from turning, although it may beheld from turning in any other manner.

The lifter 8 is provided with the usual cam follower 15 at its lower end which coacts with the cam 9 on the cam shaft and the cam coacts with the follower at one side of or eccentric to the axial line of the lifter 8 so as to tend to turn the lifter 8 about its axis constantly to take up any lost motion, if there is any in the valve mechanism, as between the lift rod and the rocker arm, or p the rocker arm and the valve stem. The cam 9 constitutes means for effecting relative turning of the lift rod 7 and lifter 8.

In operation, when there is any clearance to 'be taken up, it is automatically taken up by turning of the lifter Sand the turning movement is translated into a rectilinear. or lifting movement to the rod 7 through the cam faces 12 and 13, this lifting movement being in addition to the straight lift movement of the lifter and the lift rod.

As the valve 4 seats under the influence of the spring 6, the rod 7 is thrust downward by the rocker arm 10 and the cam faces turn the lifter 8 in the reverse direction.

What I claim is:

1. A valve operating mechanism of the class described including driving and driven axially movable members, one thrusting against the other, a guide for said members, said members having at their abutting ends complemental convex and concave cam faces with the apex of eaid faces extending diametrically of said members, whereby relative turning movement of the merribers tends to move the apex of one cam out of alinement with the apex of the other and'separate said cam faces and shift the driven member axially relatively to the driving member, and means for actuating the members axially as a unit, and tending to turn one of the members during the actuating movement to take up clearances in the valve mechanism.

2. A valve operating mechanism of the class de scribed including driving and driven axially movable members, one thrusting against the other, a guide for said members, said members having at their abutting ends complemental convex and concave cam faces with the apex of said faces extending diametrically of said members, whereby relative turning movement of the members tends to move the apex of one cam out of alinement with the other and separate said cam faces and shift the driven member axially relatively to the driving member, a rotatable lobe cam for actuating said members and coacting with the driving member eccentric to the axial line of the driving member, whereby turning of the cam when the lobe is lifting the driving member tends to turn the driving member.

CHARLES S. BROWN.

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