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. 04, 2003
Filed:
Nov. 28, 2001
Atsushi Koide, Nagano-ken, JP;
Kinji Yokoya, Nagano-ken, JP;
Nissei Plastic Industrial Co., Ltd., Nagano-Ken, JP;
Abstract
The present invention reduces an excessive gnawing force at the thread engagement region of a ball screw portion with the ball nut member that tends to be generated in the electric injection mechanism and prevents an abnormal wear or break of the ball screw shaft by installing a stress relaxation means of annular groove at the shaft portion of the ball screw shaft. A ball nut member is engaged by threads with a pair of right and left ball screw shafts rotatably provided in parallel with guide bars over front and rear plates. The shaft portion between the front plate of the ball screw shaft and the ball screw portion is partially formed with a diameter smaller that the root diameter of the ball screw shaft, and a stress relaxation groove with a concave curved surface having a flat bottom is disposed in the shaft portion.