The Egg-Cutter: Hinged Shells Hold It, a Pivoted Knife Halves It

"This invention relates to an egg cutter and has as its object to provide a device by means of which so called 'medium' and 'hard boiled' eggs may conveniently be cut in halves in their shells." The lever "is pressed down, whereby the prongs 11 keep the shells 9 closed as seen in full lines in Fig. 1, the studs 14 preventing their being closed tight. The knife 13 is then brought down and enters between the shells 9 in an obvious manner", cutting the egg into halves. Then "the shells will fold down on their hinges 8 and the halves of the egg will be open for removal."

Cut a hardwood base and two blocks, each a little bigger than half an egg. In each block, drill and chisel a hollow shaped like half an egg, split lengthways. Join the two blocks at their lower edges with a butt hinge on the base, so they close into an egg-shaped cup. Drive two screws into one block's edge and leave their heads standing 2 mm proud: they stop the blocks closing tight and leave a gap for the knife. Cut a blade from stainless steel sheet, file and hone its edge, and fix it to a wooden handle. Screw a slotted upright to the base behind the blocks and pivot the knife in the slot, so it swings down into the gap. Oil the wood with food-grade mineral oil. Close the blocks on a boiled egg, bring the knife down, open the blocks and lift out the halves. Halve six eggs and count the clean halves.

**Charles Bergmann** of Hackensack, New Jersey, filed US 1,175,922 on 6 April 1915; it was patented 21 March 1916. He preferred the base, pedestals, pin and studs formed in one piece, and held the shells shut with a forked lever on a second pedestal. **Honest limits.** The notebook treats the knife as a rigid lever and ignores friction at the pivot. Lengths and force are examples. Your count of clean halves is the measurement.