The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Dec. 07, 1993
Filed:
Dec. 02, 1991
Ryobi Limited, Tokyo, JP;
Abstract
A four-stroke cycle engine unit for a working machine, for example, generally a valve drive mechanism for driving the exhaust and intake valves. The valve drive mechanism comprises a crank cam assembly mounted to a crank shaft of the engine unit so as to be rotated in accordance with rotation of the crank shaft, a cam gear assembly mounted on the cam shaft and meshed with the crank cam assembly, a cam assembly mounted onto the cam gear assembly so as to be rotated in accordance with rotation of the cam gear assembly, a pair of first and second lifters mounted on a lifter axis portion positioned in parallel to the crank shaft, the lifters being rocked in accordance with rotation of the cam assembly, a pair of first and second push rods lifted up and lowered in accordance with rocking motions of the first and second lifters, respectively, and a pair of first and second rocker arms operated in association with the first and second push rods. The lifter axis portion and the cam shaft are positioned in a plane including the crank and a center line of a cylinder of a piston-cylinder assembly of the engine unit. The first rocker arm is connected to the exhaust valve so as to carry out open-close operation thereof and the second rocker arm is connected to the intake valve so as to carry out open-close operation thereof.