Patent ID: 6651990
Filing Date: 2003-11-25
Classification: B25B,B25D,Y10T

Abstract:
A tool holder for mounting a bit formed with a groove onto a power tool, the tool holder comprising:a tool-holding tube defining a bit insertion hole that extends in an axial direction, the tool-holding tube being formed with an elongated hole that is in connection with the bit insertion hole and that extends in the axial direction; an engagement member disposed in the elongated hole and partially protruding into the bit insertion hole, the engagement member movable in the axial direction and, when located at a retraction position in the axial direction, movable outward in a radial direction of the tool-holding tube by abutment with and pressing force from the bit being inserted in an insertion direction into the bit insertion hole; a radial movement prevention surface provided upstream from the retraction position with respect to the bit insertion direction, the radial movement prevention surface abutting against and preventing the engagement member from moving radially outward under pressing force from the bit so that the engagement member moves axially in the bit insertion direction and not radially while located axially adjacent to the radial movement prevention surface; and a resilient member disposed to an outer periphery of the tool-holding tube at the retraction position downstream from the radial movement prevention surface with respect to the bit insertion direction, the resilient member increasing in radial dimension from an initial state by pressure from the engagement member moving outward by pressing force from the bit, the resilient member resiliently returning to the initial state when pressure from the engagement member stops because the groove of the bit is located at the retraction position, thereby pressing the engagement member inward in the radial direction into engagement with the groove of the bit.