Abstract: A piston driving a brake and a clutch is split into a main piston and a secondary piston that can travel axially and that are related through limiting bolts. The main piston has a larger surface for the pressurized fluid than the secondary piston. The main piston has a duct through which the fluid flows to the secondary piston which is in turn fitted with springs that bias it, against the fluid tension, against the main piston. Therefore, when connection is made, the secondary piston first approaches the clutch discs without actually contacting the latter. After the brake is released, there is a first connection stage at which the secondary piston approaches the main piston and a second stage, after both pistons come into contact, at which the assembly works conventionally, as a single piston.

Abstract: A brake-clutch assembly applicable as a safety element in machines having a start-stop movement, such as presses, shears and the like, has a hub which is to be mounted on a machine shaft and a brake-side cover having a cylindrical part defining a cylindrical cavity for admitting compressed air. A friction disc is mounted on the cylindrical part. The hub also carries a central piston-plate which supports two rings having frictional linings on both the brake side and the clutch side. The inner diameter of the cylindrical part is considerably larger than the inner diameter of one of the locking rings, thereby allowing a maximum power to be achieved because the cylindrical cavity defining a pressure chamber can be extended to attain a diameter close to that of the friction disc. This is achieved by removing the material in an area of the central piston-plate.

Abstract: A threaded coupling includes a male part and a female part, of which one is made of a hard material such as metal and another of soft material such as plastic. The part made of the soft material is formed with a groove at a first turn of the screw thread thereof, which receives a metallic resilient ring to define a guide portion for the part of the hard material as the latter is being threaded to another part having the ring in the groove thereof.

Abstract: One planet wheel of each pair of planet wheels of a double reduction torque converter is positioned axially intermediate the or each other pair of planet wheels, in order that the unsupported length of the interconnecting gudgeon pins is reduced to the axial thickness of the or each planet wheel intermediate the said pairs of planet wheels.