Abstract: A suction device, having a suction unit for generating a suction flow and having a suction-device housing, in which a dirt-collecting chamber is arranged, which has a suction inlet and is flow-connected to the suction unit via at least one filter and a suction-extraction channel arrangement, wherein at least one external-air inlet, which can be closed by an external-air valve, is arranged on the suction-extraction channel arrangement between the filter and the suction unit, wherein the external-air valve has an external-air-valve body for closing the external-air inlet, which external-air-valve body can be moved, by movement of an actuating element along an actuation path. A transmission is arranged between the actuating element and the external-air-valve body, which transmission enables movement of the actuating element.

Abstract: A bone plate is formed with a throughgoing hole formed with a radially inwardly open outer groove. A screw fastener has a shaft engageable coaxially through the hole and a head of larger diameter than the shaft and adapted to bear axially on the plate around the hole. The shaft is formed offset from the head with a radially outwardly projecting ridge defining a radially outwardly open inner groove aligned radially with the outer groove when the fastener is fitted through the hole with the head bearing on the plate. An elastically deformable ring of a diameter generally equal to that of the hole at the outer groove is formed with at least one radially inwardly directed projection that, when the ring is fitted to the outer groove and the fastener is seated in the hole, projects radially inward into the inner groove of the fastener.

Abstract: A suction device, having a suction unit for generating a suction flow and having a suction-device housing, in which a dirt-collecting chamber is arranged, which has a suction inlet and is flow-connected to the suction unit via at least one filter and a suction-extraction channel arrangement, wherein at least one external-air inlet, which can be closed by an external-air valve, is arranged on the suction-extraction channel arrangement between the filter and the suction unit, wherein the external-air valve has an external-air-valve body for closing the external-air inlet, which external-air-valve body can be moved, by movement of an actuating element along an actuation path. A transmission is arranged between the actuating element and the external-air-valve body, which transmission enables movement of the actuating element.

Abstract: A tool for shortening an implant rod has a base housing part and a movable housing part shiftable toward and away from each other in a predetermined direction. At least one guide roller is provided on the movable housing part, and a cutter is provided on the base housing part. The rod is fittable between the cutter and the guide roller in a spread position of the housing parts. A biasing unit urges the parts together and thereby presses the cutter into the rod with a predetermined force. Thus the cutter is pressed against the workpiece with a force that does not change and that is not under the control of the user, ensuring that the force applied lies within an acceptable safe range.

Abstract: A bone plate is formed with a throughgoing hole formed with a radially inwardly open outer groove. A screw fastener has a shaft engageable coaxially through the hole and a head of larger diameter than the shaft and adapted to bear axially on the plate around the hole. The shaft is formed offset from the head with a radially outwardly projecting ridge defining a radially outwardly open inner groove aligned radially with the outer groove when the fastener is fitted through the hole with the head bearing on the plate. An elastically deformable ring of a diameter generally equal to that of the hole at the outer groove is formed with at least one radially inwardly directed projection that, when the ring is fitted to the outer groove and the fastener is seated in the hole, projects radially inward into the inner groove of the fastener.