Motor operated stapler

A motor-operated stapler, comprising:

• a magazine containing a plurality of staples to be driven out of said magazine into a bundle of sheets;
• a clincher base movable in thickness direction of said bundle of sheets held by both the magazine and the clincher base;
• a drive source provided on the magazine side for moving the clincher base;
• a pair of pivotally movable clinchers mounted on said clincher base for bending at a predetermined angle staple leg portions projecting downward from said bundle of sheets;
• a control means to increase a force for clinching the staple at the bottom surface of the bundle by said clinchers, irrespective of the thickness of said bundle of sheets when the leg portions of the staple are bent along the bottom surface of the bundle of sheets;
• a clincher pivoting mechanism for moving said clinchers pivotally;
• and
• driving cams installed on the side which holds the magazine, said driving cams coming into contact with said driven cam surfaces of the clincher links and being rotated by said drive source provided on the magazine side.

A motor-operated stapler, comprising:

• a magazine containing a plurality of staples to be driven out of said magazine into a bundle of sheets;
• a clincher base movable in thickness direction of said bundle of sheets held by both the magazine and the clincher base;
• a drive source provided on the magazine side for moving the clincher base;
• driving cams installed on a fixing means side holding said magazine;
• a pair of pivotally movable clinchers mounted on said clincher base for bending at a predetermined angle staple leg portions projecting downward from said bundle of sheets;
• control means to keep the amount of pivotal movement of said clinchers constant irrespective of the thickness of said bundle of sheets;
• a clincher pivoting mechanism for moving said clinchers pivotally, comprising clincher links installed on said clincher base to move said clinchers pivotally in vertical direction, driven cam surfaces formed respectively on said clincher links and extending in the thickness direction of said bundle of sheets to be stapled, and fulcrums provided on clincher base to convert swing motions of said cam surfaces into pivotal movement of said clinchers;
• a forming plate to form a U-shaped staple;
• and
• a driver to pierce said staple into the bundle of sheets,
• wherein said driving cams come into contact with said driven cam surfaces of the clincher links and being rotated by said drive source provided on the magazine side, and said control means are formed respectively on upper areas of said driven cam surfaces with which said driving cams come into contact and are constituted respectively by projections for causing said clinchers to further turn in a direction toward a surface of said bundle of sheets;
• position of the clincher base varies vertically depending on the thickness of the sheet bundle;
• the driving cams come into contact with the clincher links at nearly constant angle and the amount of pivotal movement of the clincher links is constant irrespective of the thickness of the bundle of sheets;
• and
• when the thickness of said bundle of sheets exceeds the predetermined value, a distance between each of said fulcrums and an abutting point formed between each of said clincher links and a driving cam is increased relatively.