Patent ID: 8181973

Claim:
A clamping apparatus for a reciprocating tool having a reciprocating spindle having a center axis and at least one radially oriented aperture and a receiving slot at its forward end for receiving a tool accessory that has a shank portion with a hole at one end and a working portion, the shank being configured to be inserted in the slot, the apparatus being configured to be attached to the spindle, said apparatus having an unclamped position and a clamped position, and comprising: a hollow generally cylindrical sleeve secured to the spindle, said sleeve having a radial aperture aligned with the spindle aperture; a hollow generally cylindrical collar configured to fit on said sleeve and being rotatable relative to the spindle and said sleeve, said collar having an inner cam surface that increases in radius from the axis through a first predetermined circumferential arc in a first direction; a spring operatively connected to provide a biasing force to said collar in a second direction opposite said first direction; and a detent pin positioned in the spindle aperture and configured to engage the hole in the tool accessory and thereby firmly hold the tool accessory in said apparatus when urged into contact with the tool accessory; said collar being biased by said spring to rotate said collar to its clamped position when the tool accessory is inserted in said slot, the rotation causing said cam surface to engage said detent pin and move it into the hole in the tool accessory and firmly hold the tool accessory in the apparatus, wherein said cylindrical sleeve has a plurality of grooves formed on an outer surface thereof and extending at an angle from the rear end forwardly, for collecting and expelling particulate material that may accumulate between said sleeve and said collar during an operation of the reciprocating tool.