Abstract: The present invention relates to a grinding machine comprising an expansion jack whose piston is connected to the expansion rod of a grinder, means for detecting the position of the piston of this jack and for supplying an electric signal as a function of this position, therefore of the expansion of the grinder, and means for comparing this signal with a reference value and for emitting, when this value is attained, a signal for stopping displacement of the piston, wherein said grinding machine comprises means for modifying the reference value in the event of wear of the grinder or shift in dimensions.

Abstract: A grinding tool with a cylindrical sleeve, having several longitudinally extending slots penetrated by radially shiftable wedge-shaped bars with abrasive outer faces, is provided with a mandrel received in the sleeve and axially displaceable therein for shifting the bars radially outward and inward. The mandrel has longitudinal guide grooves with sloping bottoms, engaged by the correspondingly sloping inner faces of respective bars, and a shallower annular groove of frustoconical bottom intersecting these guide grooves; segments of a frustoconical ring, lodged in the annular groove and projecting into the intersecting guide grooves, engage in mortises of adjacent flanks of respective bars sliding in the guide grooves for positively shifting the bars when the mandrel is displaced in one of the other axial direction.

Abstract: A tool for lapping internal surfaces of holes.Lapping tools conventionally have an expandable working portion for variable diameter operation. Known tools tend to expand in a barrel shape leading to inaccurate lapping. The invention seeks to avoid this by providing a working portion of a tubular tool with slots in a plurality of rows each having several slots. Slots in each row are staggered relative to those in adjacent rows.

Abstract: A device for supporting a steering and driving wheel of an automobile vehicle comprises a hollow hub constituting the outer element of a ball joint of which the inner element is fixed on a drive shaft, a seal element made of sheet metal being provided at the open end of the hub, opposite the joint. A brake disc having a central opening is fixed on the hub on the same side as the wheel. The seal element is in the form of a bowl whose closed end is fitted in the hollow hub and whose length is such that the other end, of outer diameter substantially equal to the diameter of the opening in the brake disc, opens outside the hollow hub and passes through the disc, centering same.

Abstract: A two-speed drive coupling for connecting an engine of a motor vehicle with an accessory such as an alternator. The coupling comprises a driving member and a driven member with a sun gear being mounted on the driven member. A planet gear wheel holder is carried on the driving member and carries planet gear wheels which mesh with the sun gear and with a crown gear locked against rotation and surrounding the sun gear. A unidirectional coupling is provided between the driving member and the driven member and a centrifugal clutch between the driving member and the holder. At low speeds of the driving member, the clutch is engaged and the driven member is rotated at a greater speed than the driving member through the planet gear wheels and the sun gear. At higher speeds of the driving member, the clutch disengages and the driven member is rotated directly by the driving member through the unidirectional coupling.

Abstract: A disc brake comprises an operating piston mounted in a cylinder rigid with a stirrup. The piston is movable in the cylinder to cause axial movement of friction linings under the action of hydraulic pressure or the force of a mechanical brake actuator. An operating clearance is provided to allow a limited retraction of the friction linings when the hydraulic pressure or the mechanical actuating force is released. The mechanical actuator comprises a screw rotatable in the cylinder. A nut engaged by the screw is connected to the piston by a unidirectional coupling device comprising teeth on the nut co-operating with teeth on a ring fixed for rotation with the piston. The nut is mounted for translatory movement in relation to the piston solely through a limited distance corresponding to the operating clearance, and the ring is mounted for axial displacement relative to the piston.

Abstract: A grinding head of the type comprising an expansible grinder adjusted by an expansion cone connected to an expansion rod, comprises a differential action hydraulic ram for operating the expansion rod. The piston of the ram is connected to the expansion rod, and the piston is slaved in position by means of a hydraulic slide valve. The valve slider is operated by a stepping motor which is program-controlled.

Abstract: A tool for lapping internal surfaces of holes. Lapping tools conventionally have an expandable working portion for variable diameter operation. Known tools tend to expand in a barrel shape leading to inaccurate lapping. The invention seeks to avoid this by providing a working portion of a tubular tool with slots in a plurality of rows each having several slots. Slots in each row are staggered relative to those in adjacent rows.

Abstract: An apparatus for removing a dead-head from a casting comprises a device for exerting on the dead-head or the casting a force which does not pass through the joining neck between the dead-head and the casting. This force generates bending moments which cause the dead-head and casting to break apart at the neck. The force can be applied by a fluid-actuated cylinder which acts on the dead-head or casting either directly or via a linkage comprising one or more levers.

Abstract: A device for controlling the expansion of an expansible grinding tool includes control means for effecting controlled axial movement of a cone in the tool. The control means includes a screw engaging a fixed nut and controllably rotatable by a driving motor, the resultant axial movement of the screw being transmitted to the cone. The expansion control device is provided in the form of a removable grinding head unit arranged to be inserted between a grinding machine and the grinding tool. The grinding head unit also includes means for transmitting rotary motion from the grinding machine to the grinding tool.