Abstract: A control for a variable reluctance motor, comprising a d.c. source, a power control circuit, and a command circuit, in which the power control circuit comprises main control switches in series with the windings of the motor to form terminal branches, the terminal branches being connected in groups of two in series between the two poles of the source in such a way that two complementary windings are never in series, as well as free-wheel branches to close the circuit of each winding when at most one main control switch in a branch is conducting, and a turn-off circuit for the main control switches, and including at least one current detector to register the current in the windings; each free-wheel branch includes a coil and a diode, the diode polarized to oppose normal current flow through its associated main control switch.

Abstract: This invention is relative at a position coder used with a variable reluctance machine to control the commutations of the stator windings on this machine, said coder being characterized by having magnetic circuits for its rotor and its stator which are identical to those on the variable reluctance machine and which are set in an identical manner.

Abstract: In a method of producing mouldings containing a thermoset binder and a fibre type filler, a fraction of the binder is injected into a heated mould while the mould parts are moving into their closure position and the remainder of the binder is injected after the mould is closed.

Abstract: A photogrammetric plotting apparatus comprises means to move two stereographic plates in their plane with respect to two respective optical systems which are arranged to project onto a single screen images of reference marks indicating the trace of the line of sight of each optical system on the respective plate. Different polarizers are disposed on the lines of sight of the optical systems so that an operator looking at the said screen through two analyzers corresponding to the polarizers sees the images of the region of one plate and its respective reference mark with one eye and the image of the corresponding region of the other plate and its respective reference mark with the other eye.

Abstract: This invention is relative to a vehicle-guiding system provided with support means and a steering means such as a roller running along a flange way, characterized in that it comprises a points system connecting a track to two tracks and formed by a point and a matching point each secured at their heel end facing the two tracks, the other ends of point and matching point bearing against one another and pivoting between a position in which tracks are connected.

Abstract: A system for detecting the distance L between two objects A and B, either or both of which may be in motion, comprising approach detector means and proximity detector means operational within overlapping distance ranges; each detector means includes an emitter mounted on a first one of the objects, which radiates a primary signal toward the second object, a responder on the second object, which radiates a similar secondary signal back toward the first object, and a signal comparator for measuring the time differential between the primary and secondary signals to determine the distance L between the objects. A range switch coupled to both comparators develops an output indicative of the distance L within a comprehensive distance range encompassing both the approach range and the proximity range and extending down to zero distance.

Abstract: Electronic safety circuit intended to produce an output signal in the event of wearing out or failure of one of its components, the circuit comprising a magnetic circuit having a rectangular hysteresis cycle, a control circuit connected to the magnetic circuit and to the other components which are under surveillance, this control circuit acting in a balanced fashion on the magnetic circuit when all the components of the circuit under surveillance function normally, but producing an unbalanced action when at least one of these components is defective, and an output circuit producing an output signal in the event of an unbalanced action on the magnetic circuit.

Abstract: The rest frequency of an oscillator supplying a sub-carrier modulated in frequency by the chrominance signal from a SECAM television transmitter, is servocoupled to a reference frequency during the frame return periods and a phase shift of the oscillator is effected during the line return periods, shorter than the frame return periods. The servocoupling device comprises a reference frequency generator, and a servocoupling loop comprising a switch member and storage means for storing a parameter which controls the rest frequency of the ocillator, and control means for actuating the switch into closed condition, so closing the loop during the frame sweep return periods. The oscillator comprises means for phase setting during line return periods, shorter than the frame return periods.

Abstract: An anti-collision safety control for vehicles travelling on tracks; the control comprises two safety loops per vehicle, linked to two common loops in a central control station. Each vehicle loop comprises control circuits for determining the distance to the next preceding vehicle, for determining a safe stopping distance for the vehicle, and for stopping the vehicle if the distance to the preceding vehicle becomes smaller than the safe stopping distance or if there is a failure of a safety circuit. The distance control circuit comprises a detector for detecting reference points provided along the track, a counter for calculating the distance of a vehicle from a given zero location, and a delay circuit for converting this distance into a position signal timed to a synchronization pulse received by all vehicles. Position signals from all vehicles are transmitted to the central control and back to the vehicles; the distance to an immediately preceding vehicle is determined by comparing the position pulses.