Patent ID: 8393625

Claim:
A tool-less blade clamping apparatus for a reciprocating tool of the type which has a reciprocating plunger with a cylindrical end portion, at least one radially oriented aperture and a blade receiving slot at its forward end for receiving a blade of the type which has a shank portion with a hole and outwardly extending shoulders on opposite sides thereof between the distal end of the shank and a main portion, the shank being configured to be inserted in the slot, the apparatus being configured to be attached to the plunger and having an opening for receiving the blade shank therein and in the slot, said apparatus comprising: a hollow generally cylindrical clamping collar configured to fit around the plunger and be rotatable relative to the plunger, and having at least one axially oriented recess extending at least part of the length thereof and an inner cam surface that begins at the inside surface thereof and increases in radius through a first predetermined circumferential arc in a first direction; a hollow generally cylindrical control sleeve configured to fit around said clamping collar, said control being rotatable and having an inwardly directed axial rib extending at least a portion of its length, said rib engaging said axial recess of said clamping collar to rotational lock said clamping collar and said control sleeve together, said control sleeve having a circumferentially extending elongated slot with a transverse axially extending slot extension; a pin secured to the plunger and engaging said slot of said control sleeve and limiting rotational movement of said control sleeve between the ends of said circumferentially extending slot and axially between the ends of said transverse axially extending slot extension; a torsion spring having one end restrained by the plunger and its opposite end retained by said control sleeve; a compression spring effectively restrained by the plunger for biasing said control sleeve toward the forward direction; a detente positioned in the plunger rod aperture and configured to engage the hole in the blade and thereby firmly hold the blade in said apparatus when urged into contact with the blade; said control sleeve being biased by said torsion spring to rotate said clamping collar when the blade is inserted into the slot and the shoulders of the blade engage said clamping collar to move said clamping collar and said control sleeve a predetermined distance, whereby said control sleeve is released to rotate relative to said plunger, causing said clamping collar to rotate so that said cam surface engages said detente to move it into the hole in the blade and firmly hold the blade in the apparatus; the blade being ejected when the control sleeve is manually rotated in the opposite direction to its position before it was released by insertion of the blade.