The Bootjack Burglar Alarm: A Spring Treadle That Grips the Heel or Bangs the Door

"My invention consists in the employment or use of two adjustable or movable jaws and a spring treadle attached to a bed or plate and used in connection with a catch, the parts being so arranged as hereinafter described that the treadle is made to perform the double function of operating the jaws when pressed down by the foot and the implement used as a boot jack, and of sounding an alarm when the implement is used as a burglar alarm and placed in proper position against a door." "This implement is quite portable may be packed in a carpet bag or small trunk without inconvenience and will be very useful in traveling."

**Bed.** Cut a bed 35 × 12 cm from plywood. Hinge a prop under its front end with a butt hinge so it can stand the jack up or fold flat. **Jaws.** Saw two curved jaws 12 × 3 cm from hardwood board and bolt each to the bed's back end near its inner end, so the outer ends can close round a heel. **Treadle.** Cut a treadle the size of the bed and hinge its front end to the bed. Glue a hardwood wedge with a 25° half-angle under its back end so it drops between the jaws' inner ends. Seat a compression spring between bed and treadle to lift it. **Catch.** Screw a sliding strip under the bed with a shoulder at each end: at one end it holds the treadle part way down for the jack; at the other it holds it right down, and a door pushing the strip's outer end frees it. **Test.** Take a rubber boot off with it and note how firmly the jaws grip. Then set it on the floor against a door, catch the treadle down, and open the door slowly: note how far it opens before the treadle snaps up against it.

**F. C. Goffin** of Newark, Essex County, New Jersey, received US 19,844, dated 6 April 1858. His bed could be solid or cast in skeleton form, the pendant was taper or wedge shaped, a prop at the front could be turned down to raise the jack or up to lie flat, and a spiral spring worked the treadle. His claim is the jaws, treadle, wedge and slide arranged for both jobs. **Honest limits.** Plywood, hardwood, butt hinges and a compression spring stand in for his cast bed, jaws and spiral spring, and the catch is a simplified sliding strip. The notebook ignores friction; its forces and lengths are examples. Your grip and door tests are the result.