Abstract: When sanding for instance panelled doors in a belt sanding machine it must be prevented that transversely extending parts (16) are sanded since it would be harmful to sand across the direction of the grain of the wood. A machine according to the invention is therefore provided with a combined sensing and control device which in a simple and effective manner will prevent damage caused by the sanding process by controlling the contact of the sanding belt with the workpiece. The device consists of a disc (14, 20) which is mounted on the sanding equipment. The disc (14, 20) protrudes a distance beyond the sanding position of the sanding belt (15), in order that the disc will sense the workpiece when the workpiece is moved under the sanding belt. When the disc (14, 20) rolls across a frame piece (16) the sanding belt (15) is pivoted up above the wood, and when the disc (14, 20) meets a recessed part (18), the sanding belt (15) is pivoted to a non-sanding position.

Abstract: To be able to control the admission of compressed air or liquid to a machine in a hand tool, the working medium can be admitted to the machine through a handle with a built-in valve. By turning the handle (1) the valve opens or closes. The valve body itself (7,9) is secured to a stay in the form of a bolt (10) and a pipe (8) screwed into the bottom of the handle casing (1), whereas the valve seat (14) is formed as a recess in a bushing (2) being stationary relative to the casing. The handle has an oblique track (4) wherein a bolt (3) secured in the bushing moves the casing (1) and thereby the valve body relative to the bushing (2) when the handle is turned. When the handle is released in the open position of the valve (FIG. 3), the pressure exerted by the medium will move the casing so as to close the valve since the area of the casing is larger than that of the bush (2). The machine can thereby be safely and reliably disconnected by releasing the hold on the handle.