Abstract: A toothed clutch is arranged between a first rotary clutch part and an intermediate part connected by straight splines to a second rotary clutch part. If engagement of the toothed clutch is attempted while the rotary clutch parts are in relative rotation in one direction, blocking members frictionally engaged with the intermediate member slide along surfaces, inclined to the axis of rotation, of baulking members carried by the first rotary clutch part and engage baulking abutments, whereby engagement of the toothed clutch is baulked. When the first and second rotary clutch parts are brought to rotational synchronism, e.g. by engagement of a friction clutch, movement of the intermediate part to engage the toothed clutch is accompanied by movement of the blocking members away from the inclined surfaces of the baulking members and clear of the baulking abutments.

Abstract: A pawl and ratchet mechanism has a baulking member which may be set in a ratcheting condition, a pawl free condition, and a baulking condition. A thrust member, engageable with the baulking member, is movable in first and second directions in which the baulking member is respectively moved towards and away from the ratcheting condition. A solenoid valve is settable in first and second conditions in which thrust is imparted to the thrust member to cause the latter to move respectively in the said first and second directions and detector means detects when the baulking member has moved into or out of the baulking condition, and into the pawl free condition, the detector means controlling the setting of the solenoid valve to that when the baulking member is in the baulking condition, the solenoid valve is so set that the thrust moves the baulking member towards the pawl free condition, the solenoid valve is so set that the thrust moves the baulking member towards the ratcheting condition.

Abstract: A power transmission system comprises a synchronous main toothed clutch 20 and a subsidiary toothed clutch 21 arranged in parallel in main and subsidiary power paths 6, 7 respectively between an input shaft 1 and an output shaft 2. When the main clutch 20 is engaged this causes engagement of the subsidiary clutch 21. The main power path 6 has a torsional stiffness which is substantially less than that of the subsidiary power path 7 over at least an initial part of the range of torque loading between zero and full power, such that at full power or at a pre-determined proportion of full power the main power path 6 and the subsidiary power path 7 transmit substantially the same load.

Abstract: A synchronous self-shifting toothed clutch comprises a first rotary clutch part carrying first and second rings of clutch teeth, a first intermediate member carrying a third ring of clutch teeth and a second intermediate member carrying a fourth ring of clutch teeth, the first intermediate member being mounted on a second rotary clutch part via interengaged helical splines of one hand and the second intermediate member being mounted on the second clutch part via interengaged splines of the other hand.When the first and second rotary clutch parts pass through synchronism in one direction of relative rotation the first and third rings of clutch teeth interengage to establish a first power path through the clutch and the second and fourth rings of clutch teeth interengage to establish a second power path through the clutch, and the two intermediate members react on one another so that the load is shared between the two power paths.

Abstract: A synchronous self-shifting toothed clutch, for use between a gas turbine and an electrical generator, of the type comprising an intermediate member which moves helically relative to a rotary clutch part in the direction to interengage the coacting clutch teeth upon passage of the rotary clutch parts through synchronism in one direction of relative rotation, and wherein a dashpot is provided for cushioning the final phase of clutch engagement.The improvement comprises a first ring of locking dogs carried by the said rotary clutch part, and a second ring of locking dogs carried by a control sleeve mounted for axial movement relative to the intermediate member. The dogs of the first ring are alternately short and long, the short dogs being narrower than the long dogs, and the dogs of the second ring are alternately short and long, the short dogs being wider than the long dogs.

Abstract: A toothed clutch of the type having a hydraulic dashpot to which liquid is fed to cushion the final phase of clutch engagement and to establish a holding pressure for resisting disengagement of the clutch.In accordance with the invention, means are provided for establishing, when required, a fluid pressure opposing the said holding pressure, so as to facilitate disengagement of the clutch without interrupting the feeding of fluid to the dashpot.

Abstract: Manufacture of a toothed clutch of the type comprising a first rotary clutch part provided with clutch teeth, a second rotary clutch part and an intermediate member provided with clutch teeth and movable relative to the second clutch part via interengaged splines to bring the coacting clutch teeth into and out of interengagement. The invention includes the step of grinding the clutch teeth of the intermediate member, or of grinding a datum diameter for use in subsequent grinding of the clutch teeth of the intermediate member, or of balancing or checking the balance of the intermediate member and the second rotary clutch part, whilst torque is present between the intermediate member and the second rotary clutch part whereby to simulate at least partly the torque conditions that exist between them when the clutch is transmitting torque. The invention also includes apparatus for use in the method.

Abstract: Electrical power generating plant of the pumped storage or air storage type comprising a unidirectional turbine, a unidirectional motor/generator and a unidirectional pump or compressor, with a synchronous toothed clutch between the motor/generator and the pump or compressor.According to the invention the clutch is in an arrangement such that its coacting clutch teeth interengage automatically when the motor/generator tends to rotate in its normal direction relative to the pump or compressor, or when the pump or compressor tends to rotate in the direction opposite to its normal direction of rotation relative to the motor/generator, and the clutch is capable of being set when required to a bi-directionally free condition such that when the plant is operating in the generating mode the motor/generator can be driven by the turbine without the pump or compressor being driven by the turbine.