Wrapping machine with severing blade in crimping head

Abstract

An article wrapping machine has superposed shafts geared together that mount opposed rotary crimping heads for crimping the wrapping between the articles. A knife blade is radially movable in a slot in the upper crimping head and is projected into a recess in the lower crimping head for severing the wrapping between a string of articles. The blade actuating mechanism comprises a rod axially movable in a bore in the shaft that mounts the upper crimping head. A pair of bell cranks is provided for projecting and retracting the blade. An intermediate portion of each bell crank is pivoted to the crimping head. An outer or free end portion of each crank is pivoted to the blade and the inner ends are pivoted to the rod. The bell cranks are disposed so that the pivotal connections to the blade pass 'over center' and the geometry of the arrangement is such that there is virtually no axial or slicing motion of the blade during its radial movement. The blade actuating rod is operated by a cam external of the machine frame which overcomes the force of a spring that is connected directly to the rod and not to the blade. A zig zag severing cut is provided without actually forming the blade as a zig zag member. This is accomplished by beveling one side of the blade and grinding notches in the flat or unbeveled side in a manner that forms specially shaped saw teeth which teeth progressively provide a zig zag severing cut.