Tool-less blade clamping apparatus for a reciprocating tool

A tool-less blade clamping apparatus for a reciprocating tool of the type which has a reciprocating plunger with a cylindrical end portion and 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 at least one outwardly extending shoulder 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:

• said apparatus having an unclamped position and a clamped position wherein the shank portion of the blade can be inserted into said opening when it is in said unclamped position and be securely retained therein when in said clamped position;
• at least one spring biasing said apparatus toward said clamped position;
• a releasable retaining mechanism for holding said apparatus in its unclamped position when placed in said unclamped position;
• said retaining mechanism being released when the at least one shoulder of the blade engages said apparatus as the blade shank portion is inserted into said opening and slot a predetermined distance to thereby place said clamping apparatus in said clamped position;
• said clamping apparatus engaging the at least one shoulder and pushing the blade shank portion outwardly therefrom when said retaining mechanism is moved to said unclamped position;
• said clamping apparatus further comprising:
• a hollow generally cylindrical inner sleeve configured to fit around the plunger and having structure engaging the slot so that said inner sleeve is axially movable and non-rotatable relative to the plunger, and having at least one outwardly extending protrusion and an inner ramp surface at its forward end that is axially oriented and inclined radially outwardly in the rearward direction;
• a hollow generally cylindrical outer sleeve configured to fit around said inner sleeve and move circumferentially and axially relative thereto, said outer sleeve having a circumferentially extending elongated slot with a transverse axially extending slot extension and at least one recess in the inside surface thereof forming a diagonal wall that extends at least through the same arc as the length of said circumferential slot and is diagonally oriented toward the front of said outer sleeve from said end of said elongated slot that has said transverse extension to said opposite end for contacting said protrusion therein, said recess diagonal wall causing said outer sleeve to rotate relative to said inner sleeve responsive to forward axial movement of said inner sleeve;
• a pin secured to the plunger and engaging said slot of said outer sleeve and limiting rotational movement of said outer sleeve between the ends of said circumferentially extending slot and axially between the ends of said transverse axially extending slot extension;
• a compression spring having one end effectively restrained by the plunger and positioned to bias said inner sleeve forwardly;
• 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 inner sleeve being biased to move forwardly when the blade is inserted into the slot and said inner and outer sleeves said predetermined distance, whereby said outer sleeve is released to rotate relative to said inner sleeve, causing said inner sleeve to move forwardly and engage 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 outer sleeve is manually rotated in the opposite direction to its position before it was released by insertion of the blade.