Card file punch

A punch mechanism for providing openings in a card-like object so it can be mounted on the rails of a file card index structure;

• said punch mechanism having a punch plate member movably hinged to a die plate member;
• said punch plate member carrying a pair of spaced punching teeth adapted to engage openings in said die plate member when said punch plate member is moved closely adjacent said die plate member;
• each of said punching teeth having a maximum of two sharp peak-like portions or crests diametrically opposite to each other for producing initial penetration of said card-like object;
• each of said punching teeth having rounded wider cutting portions or roots continuous with said peak-like portions to produce further and sequential cutting of said card-like object after said initial penetration by said peak-like portions while providing additional wear surfaces for said teeth;
• said punching teeth and said openings in said die plate member producing two cut away generally T-shaped notches in said card-like object;
• said punch plate member being hinged along an axis extending through at least two cylinders in said punch plate member and a plurality of cylinders in said die plate member;
• a cam slot in one of said cylinders of either said punch plate member or said die plate member;
• said cam slot having a shoulder therein;
• a lug on the other of said members, said lug being positioned to engage or disengage said cam slot only when said members are
• a. in a predetermined physical relationship to each other, and
• b. when manual force is applied along the direction of the hinge axis to snap said lug over said shoulder of the said cam slot, thereby resulting in a structure having a semi-press fit assembly;
• whereby said lug engages said cam slot when said members are in said predetermined physical relationship to permit assembly of said members, and said lug in cooperation with said cam slot guides said members into a coarse alignment and prevents disassembly of said members when said members are in other than said predetermined physical relationship;
• thereby resulting in a structure which can be assembled and disassembled using only manual force, yet which is not subject to inadvertent disassembly because of said semipress fit assembly even when said members are in said predetermined physical relationship.