Abstract: An apodised Bragg grating comprises a base grating section formed by a base order 5 periodic pattern of marks and spaces. The Bragg grating further comprises one or more apodised grating sections that are formed by a periodic pattern of marks and spaces, each defined by the base order pattern from which at least some of the marks are missing. The determination of which marks are missing may be performed by combining the base order pattern with a higher order modulation envelope function.

Abstract: A Bragg reflector grating comprises a plurality of chirped grating sections (65-72), in which at least a first chirped grating section and a second chirped grating section have differing ranges of grating pitches. The combined range of grating pitches provided by the first and second chirped grating sections includes at least one discontinuity, such that the first and second chirped grating sections have one or more grating pitches in common and/or there are one or more ranges of grating pitches within the combined range of grating pitches that are absent.

Abstract: A tunable laser comprises a gain section and two or more reflectors. At least one of the reflectors is a Bragg grating comprising a reduced strength section comprising a base order periodic pattern of marks and spaces from at which at least some of the marks or spaces are missing. This enables the reflective strength of the grating to be controlled relative to the other reflector. The Bragg grating may be a phase change grating with individual sections being reduced in strength by line removal.

Abstract: A Bragg grating has a local reflection strength which varies with position along the length of the grating so as to generate a non-uniform wavelength reflection spectrum, enabling compensation for a non-uniform gain profile of the gain section of a tunable laser. In another aspect, a Bragg comb grating is modulated by an envelope function which can also compensate for a non-uniform gain profile. The comb grating may be a phase change grating, with the envelope function shape being controlled by the length between phase changes and/or size of the phase changes.

Abstract: A brake system includes a brake disc having a first disc face and a second disc face on a first side and a second side, respectively, of the brake disc. The brake disc is mounted rotatably fast with but longitudinally slidable on a rotatable shaft. The brake disc is clampable between a first friction surface of a fixed brake pad positioned on the first side of the brake disc and a second friction surface of a moveable brake pad positioned on the second side of the brake disc. The system further includes a disc positioner operable to define a running clearance between the first disc face and the first friction surface. The disc positioner is adjustable to maintain the running clearance as the fixed brake pad wears. A biasing member located on the second side of the brake disc maintains contact between the disc positioner and first disc face of the brake disc.

Abstract: A parking braking system for a brake in a vehicle wherein, upon moving a parking brake selector to a park position, the brake is arranged to be mechanically locked or latched into place by means of a variable position park latch mechanism which is adapted to co-operate with an operating member of the brake so as to set the park load on the brake at a desired level. The parking braking system includes a control system which has a brake level determining means (134) to determine the brake load level at which the brake is to be parked and a control means (136) for controlling the actuation of the latching mechanism, or a combination of several latching mechanisms, to selectively maintain that brake load level during a parking phase. In order to determine the park load level to which the brake should be applied in a given situation, there is provided a static mode 1 which generates a signal representative of the static condition of the vehicle or a static compensation signal.

Abstract: A vehicle suspension system which includes a least one suspension airbag interposed between a vehicle axle and a vehicle body and a supplementary airbag positioned on a fixed support in the suspension system and extending to a structural member of the suspension system, the arrangement being such that with the suspension airbag inflated and the supplementary airbag deflated, the suspension system operates normally, and with the suspension airbag deflated and the supplementary airbag inflated, the suspension system is lifted with a consequent lifting of the axle, to bring its road wheels clear of the road surface.

Abstract: A parking braking system for a vehicle uses an electronic braking system (EBS) as a primary source for generating a parking brake force via pneumatic brake actuators. Each pneumatic actuator actuates a piston that is adapted to rotate a pivoted lever, which moves to apply brake pads against a brake disc. The parking braking system includes a hand control that controls actuation of the pneumatic brake actuators. Vehicle brakes for non-parking braking purposes are controlled by electronic signals generated in response to a driver's foot-generated braking demand. An electronic controller is adapted to control a supply of pressurized air to the pneumatic brake actuators in accordance with the driver's braking demand.

Abstract: A brake actuating apparatus includes a force transmission element operable to transmit a brake actuating force and an abutment member moveable to abut the force transmission element. A piezo-electric device operable on expansion applies a force between the abutment member and the force transmission element to move the force transmission element in a direction of brake actuation. A support member moveable independently of the abutment member supports the force transmission element in the new position following expansion of the piezo-electric device.

Abstract: A rear axle braking system for a vehicle has a primary electronic braking circuit supplied with a source of primary braking pressure and a mechanical back-up braking circuit supplied with a source of back-up braking pressure. The braking actuator receives braking pressure and thereby brakes a wheel on a vehicle axle. During braking, a changeover valve is normally actuated to apply the primary braking pressure to the braking actuator. In the event of an electronic system failure, the changeover valve is not applied and instead the source of back-up braking pressure is supplied to the actuator. A regulating valve is located in the back-up braking circuit between the source and the changeover valve and is operable as a function of axle loading and back-up brake pressure to control the supply of back-up braking pressure to the changeover valve. The application of additional braking pressure to a wheel can be limited if the loading on the axle is likely to result in vehicle instability when braking.

Abstract: A vehicle braking system having an operating member (103) by way of which a foundation braking force can be transmitted to a brake actuator in accordance with a driver's intentions, wherein there is provided a park brake mechanism (24) which provides the facility of electric motor driven actuation of the operating member (103) of the brake for the parking phase of braking.

Abstract: A parking braking system for a brake in a vehicle wherein, upon moving a parking brake selector to a park position, the brake is arranged to be mechanically locked or latched into place by means of a variable position park latch mechanism which is adapted to co-operate with an operating member of the brake so as to set the park load on the brake at a desired level. The parking braking system includes a control system which has a brake level determining means (134) to determine the brake load level at which the brake is to be parked and a control means (136) for controlling the actuation of the latching mechanism, or a combination of several latching mechanisms, to selectively maintain that brake load level during a parking phase. In order to determine the park load level to which the brake should be applied in a given situation, there is provided a static mode 1 which generates a signal representative of the static condition of the vehicle or a static compensation signal.

Abstract: A vehicle brake of the caliper type having electrically actuated active adjustment of the running clearance of a brake lining relative to a brake rotor, wherein, for brake operation, angular displacement of a rotatable component (14) of the brake by an external actuator causes axial displacement of a tappet arrangement (22, 24) within the brake whereby to transmit the actuator input load to the brake lining of the brake. The brake includes a switch for supplying a brake de-adjust signal when the brakes are to be opened for example for lining replacement. The switch is mounted on or in the body of the brake caliper and provides a non-contact switch arrangement actuated by a rotary movement provided by the rotatable component (14) of the brake in response to lining wear.

Abstract: A parking braking system for a brake in a vehicle wherein, upon moving a parking brake selector to a park position, the brake is arranged to be mechanically locked or latched into place by means of a variable position park latch mechanism which is adapted to co-operate with an operating member of the brake so as to set the park load on the brake at a desired level. The parking braking system includes a control system which has a brake level determining means (134) to determine the brake load level at which the brake is to be parked and a control means (136) for controlling the actuation of the latching mechanism, or a combination of several latching mechanisms, to selectively maintain that brake load level during a parking phase. In order to determine the park load level to which the brake should be applied in a given situation, there is provided a static mode 1 which generates a signal representative of the static condition of the vehicle or a static compensation signal.

Abstract: A parking braking system in a vehicle not having EBS wherein, for parking braking, the brakes are arranged to be supplied with actuating fluid from a pressure source under the control of a manually operated electrical device and wherein, upon selecting parking braking by actuation of the electrical device, the brakes are arranged to be applied and mechanically locked or latched in place.

Abstract: A vehicle braking system adapted to apply a brake lining to a brake rotor, and having a clearance control device for maintaining the free running clearance between the brake lining and the brake rotor during the non-braking phase, comprising an electric motor (40) for adjustment of the brake lining position relative to the brake rotor, with the adjustment being arranged to take place only during the brakes-off condition.

Abstract: A vehicle brake assembly of the kind comprises actuating means (6) for applying the brake linings (4, 5) to a brake rotor (1), adjusting means (13) adapted to be driven by the actuating means (6) for the purpose of maintaining the brake linings (4, 5) in close proximity to the brake rotor (1), and wear sensing means (60) responsive to actuation movement of the brake in a brake-applying direction. The wear sensing means (60) comprises a sensor (101) adapted to be operated by movement of an operating member (102) in a linear direction, a rotatable follower member (106) responsive to movement of the adjusting means (6), and a transmission mechanism (104) for translating rotary movement of the follower member (106) into linear movement of the operating member (102). The brake includes re-set means for resetting the relationship between a datum for the sensing means (60) and the brake during servicing of the brake.

Abstract: A brake lining wear monitor is disclosed for a brake assembly having a body and a friction lining having an operative face adapted to be applied to a brake rotor. The monitor includes an actuator which applies the brake lining to the rotor, an adjuster driven by the actuator to maintain the linings in close proximity to the brake motor, and having a wheel, and a wear sensor responsive to actuation movement of the brake which is housed within the body of the brake itself without increasing the overall package size of the brake. The wear sensor is driven from the wheel of the adjuster with an end of the sensor remote from the wheel being formed into a connector to provide a compact and integrated unit which can be removed from the brake for service without dismantling the brake assembly itself.

Abstract: A wear sensing system for the brake linings of a vehicle. Since the sensors are mounted within the brake mechanism, the reduction in the disc thickness must be taken into account to supply an accurate reading. A non-volatile memory stores the position of the brake before replacement and is compared to the position after replacement. However, the latter reading is established only after a predetermined number of brake applications to take up any starting clearances.