The use of levers in making settings on a linear scale

Abstract

Right-left-moving levers of various lengths were used to match a pointer to lighted inserts on a horizontal 9-inch linear scale with tolerances of .016 and .100 inches. Rotary control knobs were used for comparison. With lever lengths between 6 and 30 inches, the important factor seems to be the ratio of the movement of the lever-tip to the movement of the pointer. The optimal lever/pointer ratio appears to be approximately 3 or 4. A rotary knob with a ratio of about 6 inches of pointer movement for one complete turn of the knob appears to be as good as any lever combination in making settings to close tolerances on a 9-inch scale. It seems probable that this would also hold true for longer scales. (PsycInfo Database Record (c) 2025 APA, all rights reserved)