Vintage Overrunning Sprag Clutch Mechanical Demonstration Model by Formsprag

1950s - 1970s; Formsprag Clutch - Warren, Michigan

Compact salesman's demonstration model illustrating the operation and applications of an overrunning sprag clutch. The cylindrical gold-finished housing is engraved "Over-Running," "Backstopping," and "Indexing," with "Formsprag, Warren, Michigan" surrounding a black knurled control knob. Turning the knob demonstrates the clutch's one-way action: it rotates freely in one direction and locks in the opposite direction. A glass-covered window on the underside exposes the ring of individual sprags and spring mechanism for instructional viewing.

Formsprag developed from World War II-era research into an overrunning clutch for aircraft-engine superchargers and was incorporated under the Formsprag name in 1946, subsequently becoming a prominent manufacturer of industrial and aerospace clutch systems.

In very good condition with crisp, clearly legible engraved lettering and only minor surface scratches and handling wear. The knob retains its intended one-directional movement and locking action. The glass protecting the visible mechanism is in good condition without observed cracks or chips.

2.5" Diam. x 2.5" H

MM - 22754 - 102326

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