Stitching machine head and wire cassette therefor

In a wire stitching machine head having a face plate along which wire is fed from a continuous supply, a wire feed mechanism for feeding a predetermined length of wire along the face plate, a wire cutter for severing the predetermined length of wire from the supply, a wire former and driver for forming the severed length of wire into a staple and driving the staple through an associated workpiece, and a length adjuster for moving the face plate relative to the wire feed mechanism to vary the predetermined length, the improvement comprising:

• a wire cassette including a substantially closed housing having a discharge portion, a supply reel of wire rotatably mounted in the housing for accommodating unreeling of wire therefrom in a dispensing direction, guide structure in said housing for guiding the wire from the reel to the outlet, check structure on the housing engageable with an unreeled portion of the wire for preventing movement thereof in a direction opposite to the dispensing direction, a flexible and resilient lever mounted in said housing for pivotal movement between braking and release conditions, and bias means resiliently urging said lever to the braking condition thereof wherein said lever is engageable with said reel for preventing rotation thereof, said lever having a control end engageable with the unreeled portion of the wire and being deflectable in response to dispensing withdrawal of unreeled wire from said outlet, said lever being responsive to a predetermined deflection of said control end for pivoting to the release condition wherein said lever is out of engagement with the reel to permit rotation thereof for unreeling of wire therefrom;
• and support structure for releasably mounting said cassette on the face plate in a mounting condition with said discharge portion disposed for supplying wire to the wire feed mechanism.