Movement No. 128 converts continuous rotary motion into reciprocating rectilinear motion using a shaft fitted with three evenly spaced wipers (cams or lobes) acting on a rectangular frame. As the shaft rotates in the prescribed direction, each wiper in turn contacts the inside of the rectangular frame and pushes it forward. With three wipers spaced 120 degrees apart, the frame receives three impulses per revolution, producing a smoother and more frequent reciprocating stroke compared to a single-wiper arrangement. After each push, the frame returns — either by gravity, a spring, or the geometry of the next wiper — and the cycle repeats. The rectangular frame geometry ensures the wipers engage cleanly on each pass. The direction of shaft rotation is critical: reversing it would cause the wipers to catch the frame incorrectly. This mechanism is well suited for trip-hammer, stamping, or reciprocating conveyor applications requiring multiple strokes per revolution.
128. A continuous rotary motion of the shaft carrying the three wipers produces a reciprocating rectilinear motion of the rectangular frame. The shaft must revolve in the direction of the arrow for the parts to be in the position represented.