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:
Nov. 23, 1993
Filed:
Jun. 07, 1990
Satoshi Nozaki, Ibaragi, JP;
Shuichi Ajiro, Ibaragi, JP;
Hiroshi Kusumi, Ibaragi, JP;
Akio Kiue, Ibaragi, JP;
Kenichi Miyata, Ibaragi, JP;
Hitachi Construction Machinery Co., Ltd., Tokyo, JP;
Abstract
A kelly-bar apparatus includes, for example, an inner kelly-bar, a second kelly-bar and an outer kelly-bar. These kelly-bars are relatively telescopically operable and torque is transmitted from outside to inside. When the second and outer kelly-bar are in a contracted position, they are supported by a spring on a spring support fixed to the inner kelly-bar. The bottom end of a torque transmitting projection of the inner kelly-bar is fitted into and welded to the spring support. The spring support is fixed onto an engagement member formed integrally with the inner kelly-bar. In addition, a stop member for preventing the second kelly-bar from coming away from the outer kelly-bar projects from the inner periphery of the outer kelly-bar at a location above the torque transmitting portion.