Patent ID: 9038278
Filing Date: 2015-05-26
Classification: B23D

Abstract:
1. A cutting tool comprising: a rod reciprocating in an axial direction of the rod; and a blade mounting device configured to mount a blade to the rod, the blade being configured to have a shape of a band plate having a width, and the blade including a head and engaging lugs on opposite sides in a direction of the width, the blade mounting device comprising: an operation member operable to rotate between a blade mounting position and a blade removing position about an axis of the rod and biased toward the blade mounting position by a first biasing device; a blade holder disposed within the operation member and integrated therewith, and a blade guide movable relative to the rod between a restricting position and a non-restricting position in an axial direction of the rod, the blade guide being prevented from rotating about an axis and biased toward the restricting position by a second biasing device, wherein: the blade guide permits rotation of the operation member toward the blade mounting position as the blade guide moves toward the non-restricting position against a biasing force of the second biasing device, and the blade guide holds the operation member at the blade removing position when the blade guide returns to the restricting position; the blade holder engages the engaging lugs of the blade to prevent movement of the blade in a removing direction when the operation member moves to the blade mounting position, and the blade holder allows movement of the blade when the operation member is operated to rotate to the blade removing position; the blade guide includes a V-shaped guide recess that extends transverse to a longitudinal axis of the blade guide, and has a substantially cylindrical configuration; the blade guide further includes a blade insertion slot extending along the longitudinal axis of the blade guide, the blade insertion slot having a first end and a second end opposite to the first end, the first end being an open end, and the second end facing to the V-shaped guide recess; the blade insertion slot has a length in a direction along the longitudinal axis and has a width in a diametrical direction of the blade guide, the length of the blade insertion slot being greater than a length of the V-shaped guide recess in the direction along the longitudinal axis, and the width of the blade insertion slot being substantially uniform along the length thereof, the blade guide includes a pair of rotation preventing lugs provided at positions opposite to each other in a widthwise direction of the blade insertion slot, the pair of rotation preventing lugs being provided on a circumference of the blade guide for preventing rotation relative to an internal bore of the rod, and the pair of rotation preventing lugs engaging the operation member for holding the operation member at the blade removing position; the first end of the blade insertion slot is defined between a pair of holding portions opposed to each other in the widthwise direction of the blade insertion slot; the blade holder has a blade insertion opening configured to receive the blade guide, a first engaging recess and a cam surface are formed on the blade holder; the pair of rotation preventing lugs are positioned between the pair of holding portions and the V-shaped guide recess with respect to the axial direction; as the operation member moves from the blade mounting position toward the blade removing position, the blade guide moves toward the restricting position by the biasing force of the second biasing device, so that the at least one rotation preventing lug removably engages the first engaging recess to inhibit movement of the operation member toward the blade mounting position; as the operation member moves from the blade removing position toward the blade mounting position after the blade is inserted into the blade guide, the cam surface contacts the engaging lug of the blade so as to resiliently hold the engaging lug between the cam surface and the rod by the biasing force of the first biasing device, so that the blade is held at a mounting position, and a second engaging recess is formed in the rod at a position opposing the cam surface and engages the engaging lug of the blade to prevent rotation of the blade about an axis when the blade is positioned at the mounting position.