Abstract: An adjustable intermittent incremental advance system is provided having a rotatable shaft for driving a work take-off in a start-stop rotary incremental advance. A clutch disk and brake disk alternately permit or stop rotary motion of the shaft to provide the intermittent advance. A flywheel is attached to the rotary shaft and acts through a crank arm driven by a motor to provide rotary power to the shaft for predetermined incremental movement. First and second sensors provide timed application of the clutch and brake disks to provide accurate incremental advance and prevent accumulated error in length of advance during prescribed periods of operation of the system.

Abstract: An improved coupling disk and friction ring arrangement provides for long life, high speed operation of clutches and/or brake devices operated by fluid pressure as in vacuum operated clutch and/or brake devices. The improved coupling disk has stepped ring-shaped portions tapering to a minimal outer annular disk portion having greatest flexibility in the overall flexible disk. The outer portion contacts a friction ring to seal a gap therebetween and provide coupling between an axle on which the disk is mounted and a housing to give either clutch or brake output. The friction ring acts in coupling with the disk while an encircling peripheral annular portion of the disk provides a leakage gap of constant predetermined value unaffected by wear in the disk or friction material. Preferably the gap is formed by burnishing the friction material using the eccentricity of the disk to define a minimum gap. The gap has a size such as to provide a block to leakage air flow.