Grinding tool

Claim 1

A belt grinder comprising a slide assembly having defined therein an elongated channel; a first elongated arm slidably mounted in said elongated channel such that an end of the arm protrudes from the channel; a belt-driving pulley on the side of the slide assembly remote from the protruding end of the first arm; drive means for driving said belt-driving pulley; a collar fixedly mounted on the said protruding end of the first arm and defining therein a receiving channel colinear with the arm; a second elongated arm having an end portion received in the receiving channel of the collar such that the second arm is substantially colinear with the first arm; an idler pulley mounted on the end of the second arm remote from the first arm and having its axis of rotation extending transversely of the second arm; an endless abrasive-surface belt supported by the belt-driving pulley and the idler pulley and straddling the arms therebetween; end biasing means acting on the end of the first arm within the elongated channel and urging the arm to protrude from the channel, thereby to maintain tension in the belt; blocking means for preventing the first arm from sliding into the elongated channel against the end biosing means; pivot means cooperating on the second arm and the collar to permit slight pivoting of the second arm relative to the first arm in a plane which includes the axis of rotation of the idler pulley, and is parallel to the arms, thereby to tilt said axis for maintaining accurate tracking of the belt; and lateral biasing means acting on respective opposing sides of the end portion of the second arm within the collar and tending to oppose said pivoting.