Abstract: A cutter (10) intended for use on a planing blade on a road planing machine is provided with a plurality of tools (14) rotatably mounted in the cutter. The tools (14) are mounted side by side and are adapted to carry out the working of the road surface (17).

Abstract: The invention relates to a method for controlling brushless d.c. motors and to a system for controlling such motors, by varying the effective value of current pulses to the phase windings. According to the invention, upon detection of a maximum current state, the effective value of the pulses is decreased by shortening pulses from a given time point within the normally remaining part of the pulses, irrespective of whether the maximum current state ceases during the time that this part of the pulses should have occurred or not. This time point may coincide substantially with the time point at which the state of maximum current was detected or may coincide substantially with the later time point at which the duration of respective pulses exceeds a predetermined minimum value. The next pulse is introduced at the same time point at which it should normally have been introduced.

Abstract: A variable reluctance motor fed by D.C. pulses is controlled by a rotation sensor. The motor has at least two phases. The stator is designed as a continuous magnetic circuit with two stator poles per phase. The stator poles for the different phases are arranged in sequence along the periphery of the rotor so that each pole adjoins poles pertaining to another phase, and such that diametrically opposed poles pertain to the same phase, each stator pole having at least two teeth per stator pole. The rotor is provided with teeth that cooperate with the stator teeth. The spaces between adjacent stator poles are shorter than the spaces between the teeth of any one stator pole.

Abstract: A device for supplying fluid at a socket for axial not displaceably mounted tools for breaking of solid material, fluid is arranged to be supplied to a nozzle adjacent to the tool when a working tool is subjected to a counteracting force.

Abstract: The invention relates to a device for supplying fluid to a tool for breaking solid material, said tool being mounted in a holder, and that a nozzle is arranged in or in connection to the tool. A connection element for fluid transmission is arranged to bridge the opposing contact surfaces on the holder and the machine part in such a way that fluid is prevented to enter between said contact surfaces.