The Nutcracker: Two Levers, a Link and an Even Spring

"The object of my invention is to provide a nut-cracker having a spring for holding the operating handles or levers thereof in an open or distended position, with means acting in conjunction with said spring for causing said spring to act equally upon both handles or levers." Handles A and B each have a slot at the top, into which extends a cross bar or link C, pivoted to them at D and E. A cross groove F is cut in the inner face of each handle, and the link has a notch G whose walls are at right angles to its length. The spring is "a single piece of wire having a loop or head I and two divergent arms J"; the arms' ends bear in the grooves, the curved sections pass through the notch, and the loop bears on the other side of the link, so it is "put under slight compression, and consequently tends at all times to throw the handles or levers away from each other." The square-walled notch "insures equal operation of both handles or levers and prevents any seesawing motion thereof", and "no fastening devices are necessary for the spring." Other figures show a sheet-metal spring and a link with a guiding projection instead of a notch.

Measure the nutcracker's handle length from the pivot with the caliper. Crack walnuts and hazelnuts with each nut placed near the pivot, in the middle of the jaws, and near the tips. Hook the spring scale to the end of one handle while the other rests on the table, and pull until the shell cracks; note the reading. Work out the force on the shell from the lever ratio and compare the three positions with the notebook. Watch whether the handles close evenly or one moves more than the other.

**Henry M. Quackenbush** of Herkimer, New York, filed US 698,734 on 24 January 1902; it is dated 29 April 1902. Its claims cover the handles joined by a pivoted link, a spring that spreads them, and means on the link that make the spring act equally on both. **Honest limits.** The cracking forces in the notebook are assumptions; shells vary with the variety, dryness and size.