US Patent 9689441 Horizontal cam stop

A cam stop conducts rotation from a driving part, such as a tire ring, to a driven part, such as a rotary dryer or kiln. The cam stop includes a pair of support blocks securable to the driven part, and a cam rod rotatably coupled with the support blocks and extending between the support blocks. The cam rod includes a logarithmic spiral cam profile, and the cam rod is displaceable in a radial direction into engagement with the driving part by rotation according to the logarithmic spiral cam profile. Rotation of the tire ring may be conducted to the rotary drum by frictional engagement between the cam rod and the driving part.