Abstract: A knife has a hollow body, a blade movable longitudinally on the body between an extended position projecting from the body and a retracted position substantially wholly contained within the body, a biasing element engaged between the body and the blade for urging the blade into the retracted position. A latch device is transversely engageable with the body in a latched position for holding the blade in the extended position and is out of engagement with the body in a release position permitting the biasing element to draw the blade into the retracted position. An electronic circuit in the body including a microelectronic accelerometer generates an output when the body is subjected to an acceleration exceeding a predetermined acceleration threshold. An actuator between the circuit and the latch puts the latch means in the release position when the detector generates the output.

Abstract: The safety knife comprises a longitudinally slidable knife blade holder spring-loaded in the direction of the knife handle and a holding and guide piece on which the blade holder is engaged. The blade holder and the holding and guide piece on which it is mounted are received slidably and enclosed at least partially by a substantially rectangular-cross sectioned handle sleeve. Side members which are part of the blade holder and which enclose the blade are held on the holding and guide piece under spring tension by a tension spring. They are guided longitudinally slidable by guide ribs which engage in guide grooves in the holding and guide piece. One side member is provide with mounting pins which engage in mounting pin holes in the holding and guide piece for mounting and holding it in place even during blade changing when the other side member is tilted so that the blade is accessible.

Abstract: The apparatus for cutting off a substantially cylindrical piece from a cylindrical object comprises a handle with a gap like cavity in which a knife blade carried by a blade holder is pivotable. The blade holder is substantially U-shape. In the side arms of the U-shape blade holder recesses are provided which form supporting surfaces for the end regions of the knife blade. Advantageously a U-shape cover is provided with projecting pins which holds the knife blade in place in the blade holder. A transverse pivot passage in the blade holder outside of the blade contour with a radial slot extending therefrom can provide a catch opening for a pivot bolt anchored in the handle.

Abstract: A razor knife has an elongated housing formed of a front housing part and a rear housing part and having a longitudinally extending guide. The rear housing part is backwardly separable from the front housing part and carries a blade holder which has a seat for a razor blade and an actuator button exposed at a slot formed in the front housing part. This holder is displaceable by sliding of the actuator button from a back position with the blade wholly enclosed by the housing into a front position with a portion of the blade projecting forwardly from the housing. A tension spring inside the insert or back housing part continuously urges the holder into the back position. Interengaging formations on the operating button and the housing, however, allow the blade to be held in the outer position so long as a slight inward force is exerted on the slidable actuator button.

Abstract: A grooving tool has a support provided with a handle formed on its lower surface with a substantially flat sliding face and having a pair of generally parallel slots opening at this face and extending in a predetermined direction. A blade is secured in each of the two slots with portions of the blades extending beyond the face and the cutting edges of the blades forming a vertex in projection in the predetermined direction on a plane perpendicular to this direction. The parts of the support forming the lower surface can be displaceable relative to the blades to vary the spacing between the vertex and the surface for a different depth of cut. The tool can be drawn along a workpiece such as a board of insulating material so as to cut in it a very neat groove by excising a strip which may be of triangular section if the blades are planar or of semicircular section if the blades have curved lower ends.

Abstract: A cutter, especially for release of a passenger in an emergency from a vehicle seat belt, comprises a head gear formed on one end of a handle and having a beak-like formation projecting outwardly from the head toward the handle and defining with the head a converging mouth into which the seat belt can be inserted for engagement by a blade recessed in the head. A slot continues the line of the beak to guide the seat belt into engagement with the blade and a plate is laterally mounted on the head, either the plate or the head being provided with a recess accommodating the blade and dimensioned substantially to conform to the outline thereof.