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:
Jun. 25, 1991
Filed:
Sep. 29, 1989
Yukio Terunuma, Hitachi, JP;
Takao Tanabe, Katsuta, JP;
Abstract
A power-driven impact drill includes a spindle extending at a right angle to the axis of rotation of a drill bit, a rotational first hammer slidably mounted on the spindle for co-rotation therewith, and a reciprocal second hammer slidably disposed in front of the drill bit. When the rotation of the first hammer is arrested by the second hammer, the first hammer is caused by a cam mechanism to retract along the spindle in a direction away from the second hammer against the force of a first hammer spring. Upon disengagement with the second hammer, the first hammer is permitted by the cam mechanism to slide back into engagement with the second hammer under the force of the first hammer spring while it is rotated by the spindle. In this instance, the angular velocity of the first hammer received by the spindle is enhanced by the force stored in the compressed first hammer spring so that a large impact power is imposed to the rotating drill via the second hammer without substantial loss.