Engineering FAQs - Safety Chuck
Q: What is a Safety Chuck?
A safety chuck is a specialized quick coupling used for web handling operations. In order to maintain the desired tension in a web, a shaft from which a roll is being unwound must be subject to a constant level of torque from a tension brake. Similarly, a shaft onto which a roll is being wound must be subject to a constant level of torque from a motor via a slip / tension clutch. A safety chuck provides a means to transmit torque to a roll shaft as well as the ability to switch roll shafts quickly and conveniently. Unlike most couplings, a safety chuck does not require loosening and tightening of 
screws or moving any component other than the shaft and the chuck itself. Tension brakes, clutches, and motors need not be moved or dismounted.
When the locking collar or handwheel of both safety 
chucks are rotated to zero degrees, they can be tilted back (away from the roll), and the roll can be lifted out vertically. A new roll is placed in vertically and the handwheels are tilted closed to their original position. The handwheels will begin to close automatically if rotated past a few degrees (this is the safety aspect of a safety chuck).
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Safety Chucks offered by R.M. Hoffman Company:
