A punch tool for punching a slug from a workpiece. The punch of the punch tool has a reciprocating travel path with a transition region where the punch changes direction. A die plate of the punch tool has an aperture. A support bushing disposed in the aperture of the die plate provides support for the workpiece and has an underside and an opening through which the punch and the slug pass. A nozzle disposed in the aperture of the die plate provides an internal passage for the removal of punch slugs from the tool. The nozzle has a top and a side wall with a hole disposed in the side wall adjacent the transition region of the reciprocating travel path of the punch. The nozzle, the support bushing, and the die plate are integrated to form a flow path delivering a gas flow to the hole in the nozzle. The flow path and the hole direct the gas flow on a slug attached to the punch in the transition region of the reciprocating travel path of the punch to remove the slug from the punch.

According to this invention, there is disclosed a thermal conductivity substrate which includes an aluminum nitride sintered body and a coating layer formed on the body of aluminum phosphate and having a surface roughness of 1 .mu.m or less, and which has excellent humidity resistance and chemical resistance.

A holding device for a cage for roll bodies of longitudinal leaders on pillars of a tool, in particular a blanking or punching die or a mould, the tool consisting of a plurality of assembled plates, and having at least a first part and a second part. The holding device comprises a holding part which includes a hollow cylindrical rod, held displaceably in a longitudinal bore made on the free end of each pillar. Said rod is provided on its face with a disk projecting beyond the circumference of the pillar. Also inserted into the longitudinal bore is a screw. Provided on the shank of said screw is an elastic element over which an annular element, inserted into the hollow cylindrical rod, is pushed when the holding part is in pushed-in position. The elastic element holds the annular element in this position in a firmly clamping fashion. The disk in this position prevents the cage from being able to move out beyond the end of the pillar and be damaged, in particular when the tool is tilted with respect to the pillars.

A stamping device includes a base body; an elongated punch having a longitudinal axis; a supporting arrangement for holding the punch in the base body and for guiding the punch for axial displacements between an advanced position and a retracted position; a driving unit releasably held in the base body and including a driving device for axially displacing the punch; a coupling device having a first state in which the coupling device operatively connects the driving device with the punch and a second state in which the driving device is disconnected from the punch; and a receiving arrangement for holding the punch in a desired axial position when the coupling device is in its second state.

A shredding machine includes a housing which defines a passageway through which a sheet of material to be shredded may pass, a punching mechanism comprising a plurality of punch members, a mechanism to move the punch members from a retracted position in which the punch members are spaced from the passageway to an advanced position in which the punch members extend through the passageway, and a feeding mechanism for feeding the sheet of material through the punching mechanism so that repeated movement of the punch members between the retracted and the advanced positions effects shredding of the material. A method of shredding sheet material comprises feeding a sheet of material to be shredded past a punching mechanism and repeatedly punching the sheet material so as to shred the entire sheet.