Abstract: To turn off a television set for a selected period of time during a commercial and have it automatically turned on after that time, a timer includes a telephone-type dial outside of the front panel which turns a ratchet-cam wheel inside the housing of the timer. The ratchet-cam wheel includes a plurality of notches in its rim and a plurality of posts corresponding to the openings in the telephone dial and to periods of time, with a push-button switch being closed when the telephone dial is in its initial position by a large notch in the rim of the ratchet-cam wheel and opened when it is displaced from that position. To disconnect the television set, a timer motor drives a spring-biased ratchet wheel so that turning the dial moves the posts past the teeth of the ratchet and opens the switch and the timer motor turns the teeth of the ratchet to slowly move the dial back into position where the switch is closed.

Abstract: A self-drilling fastener includes a shank having a drill tip integrally formed on one end thereof and a head on the other end. The drill tip is defined by two concave grooves formed one on each side of the shank and intersecting with two planar heels formed on the end of the shank to define two cutting edges. Each of the cutting edges is formed with a positive rake angle along the entire length thereof with the rake angle increasing in magnitude upon progressing outwardly along the cutting edge and toward the periphery of the shank. The axes of the grooves are straight and form an acute included angle bisected by the axis of the shank. The heels also intersect at an angle bisected by the axis of the screw, the edge of intersection of the heels defining a chisel edge at the tip of the shank.