Mortising apparatus

Abstract

A mortising machine adapted for connection to a conventional electric motor includes a frame having rotatably mounted therein a helically-grooved shaft on which is threadedly mounted a router assembly carrying a rotatable router bit for reciprocation along the grooved shaft upon its rotation. The shaft of the router bit and the grooved shaft are both driven from a drive shaft journaled in the frame by a drive connection arrangement of pulleys and timing belts to simultaneously rotate and reciprocate the router bit for cutting a linear mortised slot. For driving the shaft of the router bit, the drive arrangement includes a pulley on each of the drive shaft and router bit shaft, a traveling idler pulley mounted on an arm pivoted on the router assembly, and a timing belt trained about the pulleys. The traveling pulley is biased by a spring away from the drive shaft into a position relative to the drive shaft and the shaft of the router bit and moves reciprocably with the router assembly against the biasing force of the spring such that the drive arrangement extends and contracts reciprocably with the router assembly, the traveling pulley acting as an idler to maintain tension in the timing belt, thereby to provide a continuous drive connection between the drive shaft and the router bit throughout reciprocation of the router assembly. The frame is substantially enclosed except for a slot through which the router bit extends and reciprocates, a belt arrangement being affixed to the router assembly on opposite sides of the router bit for reciprocation with the router assembly in covering relation to the slot to prevent entrance of debris into the frame.

Dependencies are inferred from the claim text.