Hollow core chucking device

A chucking device for engaging the hollow core of a web of material comprising:

• a. a tapered chuck plug consisting of a generally cylindrical and tapered body portion and an enlarged base portion;
• b. means for attaching the base portion of said tapered chuck plug to a rotatable spindle;
• c. an opening formed in the tapered end of said chuck plug comprising an elongated slot that extends internally of the chuck plug from its back portion to the extreme tapered end thereof where the slot opens into the surface face of said chuck plug;
• d. a pair of oppositely disposed core engaging elements pivotally mounted in said opening, said core engaging elements comprising a pair of chuck dogs which are pivotally mounted in said elongated slot at opposed sides of said chuck plug for movement from a normal retracted position within said chuck plug to a core engaging position exteriorly of said chuck plug, said chuck dogs being generally aligned with one another and consisting of angular elements that are sharpened at their core engaging ends and which have means at their opposite ends for accepting and retaining a compression spring device that normally biases the chuck dogs into their retracted position within the chuck plug slot;
• and,
• e. means located in said chuck plug for urging said chuck dogs into contact with the inside of a core placed on said chuck plug, said means comprising a slide element having an elongated cylindrical body with a slotted central portion for accomodating the opposite ends of said chuck dogs and said compression spring device located in said chuck plug base, said slide element further comprising a threaded upper portion which accomodates a set screw element and a solid lower portion having a raised base section wherein mechanical actuation of said set screw serves to overcome the compression spring bias to urge the sharpened ends of said chuck dogs into their core engaging position.