The Folding Chair: Pins in Slots Until It Is Only a Frame

"The chair is composed of a main frame, which constitutes the front legs and back frame of the chair, of a seat, and back legs, which cross the front legs, and these parts are so connected with each other that the chair may be folded up perfectly flat and with the seat and back legs entirely within the main frame, and may be opened either way and used whichever way it may be opened." "As all of the pieces used to compose the seat and legs are straight pieces, when the chair is folded it is perfectly flat, and is of no greater thickness than that of the material used". "The front legs are formed on their inner sides with slots or grooves d d, at the bottom of which rest pins e e, secured to the seat. When the chair is being folded, the pins e e slide upward in the slots d d". The patent adds a back "composed of strips r r, pivoted together to form what is termed a 'lazy-tongs'", and a groove in the bottom cross-piece into which "the beveled ends of the back legs are lowered after being folded within the main frame, preventing the legs from being turned and thus locking the chair."

Draw the chair full size first, in side view: a main frame of two front legs joined by top and bottom cross-pieces; a seat between the front legs; two back legs pivoted at the front edge of the seat, crossing the front legs. Mark where each pin sits open and where it must slide to when folded. Scale it to one fifth. Cut the parts from thin pine strips. Cut the slots in the front legs (for the seat pins) and in the back legs (for the front-leg pins) with a drill and coping saw; short lengths of dowel are the pins. Glue only the fixed joints. Fold it. If it will not lie flat, a slot is too short: lengthen it until the back legs clear the bottom cross-piece, as the patent says. Measure its folded thickness against a board's. Open it and press on the seat: the pins should sit at the slot ends.

**James C. Merritt** and **Lawrence A. C. Müller** of Highland Falls, New York, filed US 317,402 on 3 December 1883; it is dated 5 May 1885. Müller assigned his share to Joseph Denton. The patent calls it a "reversible folding chair": it opens either way. **Honest limits.** The patent gives no dimensions. The board thickness, heights and spreads in the notebook are examples; take the model's sizes from your own full-size drawing.