The Fire Screen: Counterweights That Lift It Into the Mantel

"My invention is a combined screen and fire-fender, and is a novel and useful device for having a combined screen and fire-fender always on hand, and so conveniently arranged that it can be put in place or withdrawn from sight by one motion of the hand and in one moment of time. This screen works in the mantel-piece by means of weights, and is secured in position by means of a spring-latch that catches in notches in the jamb." "This screen thus arranged can be made to answer for three purposes: By letting it nearly down to the hearth it acts as a blower; by letting it entirely down accidents from fire are prevented, and when let down in the summer time it makes a handsome summer screen." "The weights are made heavier than the screen, so that when the spring-latch is withdrawn from notches d d the screen will retire into recess F of its own motion. The screen is made flat, square, or nearly so, and may be of solid sheet-iron ... or it may be perforated or made of wire properly bound." "When the mantel-piece is made of wood it should be lined with sheet metal, to keep it from taking fire from heat radiated from the fender or screen."

Fix a pulley high on a frame or door lintel. Tie a plywood board (the 'screen') to one end of a rope over it, and a bag of sand slightly heavier than the board to the other. Weigh both first. Hold the board down, release it, and time its rise over a measured height with a stopwatch; do it five times and average. Add sand in steps and repeat. Compare each rise time with the notebook's Atwood formula; the difference is friction. Keep feet clear of the falling weight.

**James C. Matthews** of Canton, Texas, filed US 244,397 on 10 May 1881; it is dated 19 July 1881. **Honest limits.** The patent gives no weights or sizes. Masses, rise height and opening sizes in the notebook are examples, and the Atwood model leaves out friction in the grooves and pulleys.