IIVVE/V-TUR Foyfffiedbwy R. E HEDBERG VALVE ROCKER ARM Filed Jan. 31
A TTORNEYS Patented Sept. 25, 1923 U FATS ROY EDGAR HEDBERG, 0F GRENFELL, SASKATCHEWAN, CANADA.
VALVE ROCKER ARM.
Application filed January 31, 1922. Serial No. 533,113.
T 0 all whom it may concern Be it known that I, ROY E. HEDBERG, a citizen of the United States, and a resident of Grenfell, Saskatchewan, Dominion of Canada, have invented a new and useful Improvement in Valve Rocker Arms, of which the following is a full, clear, and exact description.
This invention relates to improvements in rocker arms, particularly to a rocker arm of the class commonly employed for operating the valves of internal combustion engines.
An object of the invention is to provide a rocker arm of this character, so constructed that all play between the rocker arm and the valve operating parts is automatically taken up as soon as it appears through wear or through expansion and contraction of the valve operating parts and the engine.
A further object is to provide a device of this character so constructed that there is no danger of the valve being held off its seat allowing a leakage, and a rocker arm which will cause the valve operating parts to operate silently and in exact time with the rest of the engine, thus insuring a quieter and better running engine.
Still another object is to provide a cushioned rocker arm as opposed to the solid rocker arms now commonly employed, and to provide adevice of the character stated which will be simple and practical in construction, strong, durable and eiiicient in use, and comparatively inexpensive to manufacture.
With these and other objects in view, the invention consists in certain novel features of construction and combinations and arrangements of parts as will be more fully hereinafterdescribed and pointed out in the claims.
In the accompanying drawings: I
Figure 1 is a view partly in section and partly in elevation showing a valve and its operating parts, in connection with a cylinder block of an internal combustion engine;
Figure 2 is a view in section on the line 22 of Figure 1.
Referring in detail to the drawings, 1 represents the cylinder block and 2 an engine valve normally held against its seat by a valve spring 3 located around the valve stem 4. A rocker arm shaft'5 is mounted in suitable brackets 6 upon the cylinder block. I have used the reference numeral 7 to designate a conventional type of cam shaft carrymg a cam 8, which is engageable with a push rod 9 to operate the valve 2 through the medium of a rocker arm 10. The invention in this case resides prineipallv in the unique construction of'the rocker arm and it is to be understood that the following description of the rocker arm is merely a description of. one method of carrying out the invention, and that various slight changes in construction might be resorted to as long as the objects of the invention are carried out,
The rocker arm 10 is provided with a central circular opening providing a bearing surface 11 for an eccentric bushing 12 mounted to turn freely on the rocker arm shaft 5. A pin or screw 13 screwed into the rocker arm 10 rides in a slot 14 in the bushing, thus preventing lateral movement of the bushing relative to the rocker arm. The screw 13 is preferably formed with an oil receiving cup 15 in its outer end. An oil passage 16 through the screw and a similar passage 17 in the bushing serve to lubricate s9 the inner and outer bearing surfaces of the bushing.
A coiled expansion spring 18 is interposed between the screw "13 and that end of the slot 11 which is in the high side of the bushing 12.
The operation of the device is as follows: I have shown the valve 2 in closed position, with all clearance between the valve stem and rocker arm, the rocker arm and push rod and the push rod and cam taken up. It will be readily understood that turning of the cam shaft will operate through the medium of the push rod to rock the arm 10, positively effecting opening of the valve 2 through the medium of the valve stem 4 against the action of the spring 3. During this operation the eccentric bushing has a tendency to remain stationary due to the pressure on the high side of the bushing. As
the valve again closes, the bushing is carried by the rocker arm sliding on the shaft 4,- the result being that when the valve is seated there is a slight clearance between the too ends of the rocker arm and the valve stem and push rod respectively. This clearance is immediately taken up by the spring 18 urging the eccentric downwardly and preparing the valve operating parts for the no tained by making slight changes in the con-' struction of the rocker arm. I wish it understood, therefore, that numerous slight alterations might be made without departing from the spirit and scope of the appended claims, and that various other uses might be found for the rocker arm in addition to its use on internal combustion engines.
1. In a rocker arm, the combination with a shaft,-of an eccentric bushing journaled on the'shaft, a rocker arm journaled on the bushing, and a spring urging the bushing and rocker arm to turn together in one di rection, said bushing having a slot therein wherein said spring is located, and an inwardly extending member carried by the arm, riding in the slot and engaged by the spring.
2. In a rocker arm, a shaft, an eccentric bushing journaled on the shaft, a rocker arm journaled at its intermediate portion on the bushing, said bushing having an arcuate slot therein, a screw carried by the arm and extending into the slot, a spring interposed between the end of the slot and the screw urging simultaneous movement of the arm and bushing in one direction.
3. In a rocker arm, a shaft, an eccentric bushing journaled on the shaft, a rocker arm journaled at its intermediate portion on the bushing, said bushing having an arcuate slot therein, a screw carried by the arm and extending into the slot, a spring interposed between the end of the slot and the screw urging simultaneous movement of'the arm and bushing in one direction, said screw and bushing having oil passages therein adapted to efiect lubrication of the inner and outer bearing surfaces of said bushing.
4: In a rocker arm, the combination with a shaft; of an eccentric bushing journaled on said shaft, a rocker arm journaled on said bushing, and resilient means interposed between said bushing and rocker arm for causing the bushing and rocker to turn together in one direction.
ROY EDGAR HEDBERG.