Abstract: A power transfer unit includes a differential gear set, first and second pump/motors, an electric motor/generator, and first and second hydraulic circuits. The differential gear set includes a first input/output member, a second input/output member, and a third input/output member. The first pump/motor is coupled to the first input/output member. The second pump/motor is coupled to the second input/output member. The electric motor/generator is coupled to the third input/output member. The first hydraulic circuit is hydraulically coupled to the first pump/motor. The second hydraulic circuit is hydraulically coupled to the second pump/motor and hydraulically separated from the first hydraulic circuit.

Abstract: A coupling for use in a transmission system and between coaxial rotary members which are arranged for driving engagement through axially engaging teeth thereon, one of said members being connected, directly or indirectly by helical splines to a further part such that in normal rotation, the said one member has a force exerted upon it tending to separate the teeth, such force being resisted by a fusible element which will melt when temperature rises above a predetermined value, melting of said element permitting axial movement of said one member relatively to said further part, through the splines to permit disengagement of the teeth, bearings supporting said further part, being substantially free from axial loading and spring means being provided for preventing re-engagement of the teeth after the element has melted.

Abstract: A coupling for use in a transmission system and between rotary members which are arranged for driving engagement through axially engaging teeth thereon, the teeth being shaped to tend to disengage when normally driving in one direction, one of said members having two components connected by helical splines, the components being prevented from moving axially to disengage the teeth by a fusible element which will melt when temperature rises above a predetermined value, melting of said element permitting movement of the components axially to disengage the teeth and the helical splines permitting axial relative movement between the two components, when reverse rotation is taking place, to permit ratcheting of the teeth.

Abstract: A transmission system including two axially spaced torus discs or rotors, one serving as an input and the other as an output and between which there is a set of circumferentially spaced drive rollers in frictional rolling contact with part toroidal surfaces on the discs, each roller being mounted in a bearing structure which can tilt about an axis at right angles to the axis of rotation of each roller to vary the distances from the gear axis at which the roller engages the two discs respectively to vary the ratio of the gear, means being provided for moving each roller bearing structure generally tangentially of the gear axis, and arranged to apply a force to said structure in a direction non-parallel with respect to the plane which is perpendicular to the gear axis and there being means for accommodating the effective movement of the roller bearing axes relatively to the gear axis in a direction parallel to the gear axis.

Abstract: An electric generator arrangement comprises a generator and a continuously-variable ratio drive, whereby the generator can be driven at a constant speed over a range of speeds applied to an input shaft. The drive comprises an epicyclic differential gear having a planet gear carrier driven by the input shaft, a sum gear coupled to coupled to the generator and a ring gear. The ring gear can be driven at varying speeds by hydraulic units to vary the ratio of the speeds of the input shaft and the sun gear. The hydraulic units are driven by the input shaft and the speed of the ring gear is controlled by an electro-hydraulic control system which is responsive to the frequency of an output signal from a part of the generator. Fluid under pressure for the hydraulic units and the hydraulic control system is provided by a combined pump and de-aerator on the shaft of another part of the generator.

Abstract: An axial loading device for use, for example, in a transmission system having toroidal discs with rollers engaged between toroidal surfaces thereon, the device including spring means acting beween an abutment and a member to which axial pressure is applied, the member being axially movable relatively to the abutment and the spring means acting on one part of said member in a first axial position of said member and acting on a further part of said member when it is in a further axial position, the said one part of the member being spaced from said further part of the member radially of the axis thereof so that differential axial loading is applied to said member by said spring means when the member occupies said first and said further axial positions, respectively.

Abstract: A transmission system comprising two axially spaced torus discs or rotors, one serving as an input and the other as an output, and between which there is a set of circumferentially spaced drive rollers in frictional rolling contact with part toroidal surfaces on the discs, each roller being rotatably mounted in a bearing structure which can tilt about an axis at right angles to the axis of rotation of each roller so as to vary the distances from the gear axis at which the roller engages the two discs respectively, thus varying the drive ratio of the gear and means for moving each of the roller bearing structures generally tangentially with respect to the axis and arranged to apply a force to said structure in a direction to vary the castor angle, there being means for accommodating effective movement of the roller bearing axes relatively to the gear axis in a direction parallel to the gear axis.

Abstract: An electrical generator arrangement includes a variable-ratio drive device, an alternator driven by the drive device and a generator which is separately excited by the alternator output. An over-running clutch connects the alternator and generator rotors so that in the event of an alteration in the driving output from the drive device the generator can continue to rotate with its normal speed and direction but the frequency of the alternator output provides an indication of the operating state of the drive device.