Abstract: A chainless drive mechanism for a bicycle using pedal arms, one on each side of the bicycle, each pedal arm carrying a pedal engageable with a rider's foot. Each pedal arm is mounted to a crank by a rotating joint and connected to the frame of the bicycle by a link, each link having rotating joints at each end. The cranks are connected by a shaft passing through the hub of to the driven wheel of the bicycle. The cranks may be connected to the driven wheel by a multi ratio free wheeling gear mechanism.

Abstract: A gear reduction mechanism, particularly for use in an offset final drive unit for vehicular applications, has an input gear meshing directly with the output gear and two additional gear trains between the input and output gears. Three separate load paths therefore exist for the transmission of torque from the input gear to the output gear which means that the face widths of all the gears can be substantially reduced in comparison with a conventional single-mesh arrangement and the overall mechanism can therefore be of reduced width.

Abstract: A drive configuration for a skid steered vehicle comprises a pair of electric motors for propulsion of the vehicle, one each coupled to drive a respective track on a respective side of the vehicle, and one or more electric steer motors coupled through a differential gear mechanism to impose a speed difference between the tracks. An associated control system controls the current to each motor so that substantial contributions to the differential torque to turn the vehicle are made both by the steer motors and by the propulsion motors, in variable proportions preferably as a function of the vehicle speed.

Abstract: A controlled differential, particularly for exercising steering control of skid steered vehicles, having a compound planetary gear set coupling two shafts. Respective ring gears turn with the shafts and mesh with a compound planet gear in a planet carrier, the ratios of the number of gear teeth between each ring gear and the respective gear of the compound planet being unequal so that when the planet carrier is stationary the two shafts are coupled through the differential to turn together in the same sense but with a speed difference, and controlled rotation of the planet carrier varies the speed difference between the shafts in accordance with the sense and speed of rotation of the planet carrier.

Abstract: A drive configuration for a skid steered vehicle incorporates a controlled differential for use in exercising steering control of the vehicle, comprising a compound planetary gear set (8) coupling two shafts (7a, 7b). Respective sun gears (10a) and (10b) turn with the shafts and mesh with compound planet gears (12) in a common planet carrier (13), the ratios of the number of gear teeth between each sun gear and the respective gears (14a) or (14b) of the compound planets being unequal so that when the planet carrier is stationary the two shafts are coupled through the differential to turn together in the same sense but with a speed difference, and controlled rotation of the planet carrier varies the speed difference between the shafts in accordance with the sense and speed of rotation of the planet carrier.

Abstract: A final drive assembly, particularly for a skid steered vehicle, comprises a planetary gear reduction mechanism of which the input is through the sun gear 38 and the output is through the planet carrier 43. The sun gear is formed on a hollow shaft 26 which is driven by a coupling shaft 18a extending coaxially within it. These shafts are coupled through a coupling member 31 splined to each shaft, the larger diameter coupling 32 with the hollow shaft 26 being a crowned spline coupling to accommodate angular misalignment between the shafts.

Abstract: A gear reduction and coupling assembly, particularly for incorporation in a transverse drive arrangement for a skid steered vehicle, comprises a planetary gear mechanism having an input through the sun gear and an output through the planet carrier. A coupling member is coupled to the carrier through a crowned spline coupling and is coupled to a subsequent transmission member such as a shaft through a parallel splined coupling, the diameter of the crowned spline coupling being substantially greater than the diameter of the parallel splined coupling. In this way a degree of angular misalignment between the subsequent transmission member and the planet carrier can be accommodated while a similar torque transmitting capacity can be achieved for both of the couplings with the coupling member.

Abstract: A drive configuration for a skid steered vehicle comprises a pair of electric motors for propulsion of the vehicle, one each coupled to drive a respective track on a respective side of the vehicle, and one or more electric steer motors coupled through a differential gear mechanism to impose a speed difference between the tracks. An associated control system controls the current to each motor so that substantial contributions to the differential torque to turn the vehicle are made both by the steer motors and by the propulsion motors, in variable proportions preferably as a function of the vehicle speed.

Abstract: A controlled differential, particularly for exercising steering control of skid steered vehicles, having a compound planetary gear set coupling two shafts. Respective ring gears turn with the shafts and mesh with a compound planet gear in a planet carrier, the ratios of the number of gear teeth between each ring gear and the respective gear of the compound planet being unequal so that when the planet carrier is stationary the two shafts are coupled through the differential to turn together in the same sense but with a speed difference, and controlled rotation of the planet carrier varies the speed difference between the shafts in accordance with the sense and speed of rotation of the planet carrier.

Abstract: An electric drive transmission for a skid steered vehicle has a central casing housing a pair of propulsion motors comprising respective stators and rotors, each rotor being coupled to drive a respective through shaft via a respective epicyclic gear change mechanism. The through shafts are coupled at their inboard ends to a controlled differential with an input from a steer motor, and are coupled at their outboard ends to respective epicyclic gear reduction mechanisms. The through shafts are supported in the casing by respective bearings and the propulsion motor rotors are supported on the through shafts by respective bearings. By supporting the rotors on the through shafts rather than in separate bearings to the casing the diameter and speed rating of the requisite rotor bearings can be reduced.

Abstract: A self-energising brake assembly, particularly for braking a drive shaft of a heavy tracked vehicle such as a tank, has a pair of discs carrying friction pads borne to rotate with the shaft. These friction discs are located to either side of a central non-rotating water-cooled disc assembly. A control brake disc is also borne to rotate with the shaft but capable of turning relative to the same via a ball screw assembly. To apply the brake the control disc is retarded relative to the shaft by means of an associated caliper, which causes relative axial movement between the inner and outer rings of the ball screw. This movement drives the friction disc axially along the shaft, on a ball spline, towards the friction disc, thus clamping the non-rotating disc between the two friction discs and braking the shaft.

Abstract: A liquid-cooled brake disc comprises a central stationary aluminium cooling plate (14) with an internal chamber (17) for the circulation of water or other liquid coolant, and a series of cast iron sectors (20) mounted on opposite sides of the plate for contact by conventional brake friction material carried by discs on a shaft to be braked (not shown). The cooling plate (14) and sectors (20) are separated by thin air gaps (22) or other thermally insulative layers. In use the sectors (20) have sufficient thermal capacity to store the heat generated by a braking event over a relatively short period, and this heat is then transferred to the coolant over a relatively longer period at a rate determined by the conductance of the air gaps. In particular this form of construction can absorb and dissipate the heat of braking without bulk boiling of the coolant.

Abstract: A drive configuration for a skid steered vehicle incorporates a controlled differential for use in exercising steering control of the vehicle, comprising a compound planetary gear set (8) coupling two shafts (7a, 7b). Respective sun gears (10a) and (10b) turn with the shafts and mesh with compound planet gears (12) in a common planet carrier (13), the ratios of the number of gear teeth between each sun gear and the respective gears (14a) or (14b) of the compound planets being unequal so that when the planet carrier is stationary the two shafts are coupled through the differential to turn together in the same sense but with a speed difference, and controlled rotation of the planet carrier varies the speed difference between the shafts in accordance with the sense and speed of rotation of the planet carrier.

Abstract: A gear change mechanism coupling a pair of shafts employs a planetary gear set comprising a sun gear fast with a first of the shafts, planet gears in a planet carrier, and an annulus or ring gear, the latter being fixed. A selector hub slidable on the other of the shafts has sets of radially spaced dogs to engage with corresponding dogs on the planet carrier and sun gear respectively, so as to couple the shafts at two different ratios depending on the axial position of the selector hub. This results in a more axially compact package than conventional dog clutch gear changers. In an alternative embodiment a reversing mechanism is provided by fixing the planet carrier and engaging the selector hub with the sun gear or annulus depending on its axial position.

Abstract: An electric drive configuration for a tracked vehicle comprises a pair of propulsion motors (1a, 1b) each in operable communication with one of a first pair of track drive sprockets (3a, 3b) for driving a pair of tracks (4a, 4b) of the tracked vehicles; a steer motor (5) in driveable communication with a controlled differential steer gear unit (6) positioned centrally of a pair of steering cross-shafts (7a, 7b) and in driveable communication with each shaft, the opposing ends of the steering cross-shafts (7a, 7b) being each in operable communication with one of a second pair of track drive sprockets (9a, 9b) for controlling the relative speeds of the two track to steer the tracked vehicle; the first pair of track drive sprockets (3a, 3b) being engageable with the tracks (4a, 4b) at a first end of a tracked vehicle and the second pair of track drive sprockets (9a, 9b) being engageable with the tracks at a second end of the tracked vehicle.

Abstract: An electric drive configuration for a tracked vehicle comprises a pair of propulsion motors (1a, 1b) each in operable communication with one of a first pair of track drive sprockets (3a, 3b) for driving a pair of tracks (4a, 4b) of the tracked vehicle: a steer motor (5) in driveable communication with a controlled differential steer gear unit (6) positioned centrally of a pair of steering cross-shafts (7a, 7b) and in driveable communication with each shaft, the opposing ends of the steering cross-shafts (7a, 7b) being each in operable communication with one of a second pair of track drive sprockets (9a, 9b) for controlling the relative speeds of the two track to steer the tracked vehicle; the first pair of track drive sprockets (3a, 3b) being engageable with the tracks (4a, 4b) at a first end of a tracked vehicle and the second pair of track drive sprockets (9a, 9b) being engageable with the tracks at a second end of the tracked vehicle.