Abstract: An electrical limit switch (10) is provided and comprises a number of contact elements (30) each having a slot (32) with inner cutting edges (34) for penetrating the insulation of and containing a conducting element (48). The contact elements (30) are provided on a body which engages a base (56) wherein the base (56) receives a plurality of conducting elements (48). Upon engagement of the body and base (56), the conducting elements (48) are foced into respective slots (32) in the contact elements (30), thus providing a rapid electrical connection. The switching means of the limit switch (1) is provided by an actuating arrangement (14) including a plunger portion (16) and a roller (18), wherein the plunger(16) includes electrical contacts (36a, 36b) which are moveable with the plunger. Each contact (36a, 36b) provides an electrical connection between two of the contact elements (30) when the plunger (16) is in the appropriate position.

Abstract: Methods and apparatus for introducing a plurality of optical markers to a field of view, capturing a two-dimensional image of said field of view on an image plate comprising a pixel array, determining a set of marker origin offset values and using said offset values to establish a set of orientation values describing the relationship between the field of view and the image plate are disclosed. These orientation values are used to relate the area of image captured by each pixel in the image plate to the real world. By applying projective geometry, vector analysis and trigonometrical surveys an image analysis is conducted to establish a three-dimensional positional data set describing the three-dimensional position of regions of reflectivity in the captured two-dimensional image. From this data set a three-dimensional model of the field of view can be reconstructed.

Abstract: A generator controller (4) is provided which is able to detect and respond to failure of a generator output voltage sensor, whilst being able to distinguish voltage sensor failure from output voltage collapse due to the presence of an overload or short circuit condition. The presence of a voltage sensor failure is indicated by the measured output voltage being below a first voltage threshold whilst the output current is also below a current threshold.

Abstract: A fuel control system for controlling the supply of fuel to an engine, the control system comprising: pump means for providing a flow of fuel to said engine; first and second drive means for driving said pump means; and, control means for controlling said first and second drive means; wherein, said control means is arranged to control said first and second drive means such that in the event of failure of one of said first and second drive means, said pump means is driven by the other of said first and second drive means.

Abstract: A compensation circuit is provided for use in a drive arrangement for an isolation transformer in series with a capacitor. The compensation circuit applies a compensation voltage to the capacitor such that the voltage across the capacitor remains substantially invariant.

Abstract: An unpressurised aeronautical generator (2), is provided which includes a two stage oil pump (6) comprising a centrifugal pump (8) and a gerotor pump (26). The centrifugal punp draws oil through openings (18) in a manifold, pressurises it and supplies it to the gerotor pump. The gerotor pump then pumps the pressurised oil throughout the generator. A small gerotor pump is used, which is still sufficient to operate at low pressures and high altitudes.

Abstract: A rotor assembly for a dynamo electric machine, the rotor assembly comprising a rotor core incorporating radially extending rotor poles, rotor windings encircling respective rotor poles, circumferentially extending pole tips at the outer end of each pole respectively, said tips overlying the rotor winding encircling the respective pole, a plurality of rotor slot closure members, each closure member spanning the gap between a pair of adjacent poles, and including lateral flanges interposed between the respective rotor windings and the associated pole tips, a spacer member positioned beneath each closure member and engaging the radially extending faces of the adjacent windings, and, a locking wedge assembly comprising a pair of locking wedges extending axially of the rotor assembly between each closure member and the associated spacer, the locking wedges extending with their tapers in opposite directions so that moving the wedges longitudinally towards one another increases the radial dimension of the combinati

Abstract: An AC to DC converter with harmonic suppression is provided. The harmonic suppression is provided by forcing an instantaneous current conflict between series connected rectifier bridges 54, 80, such that a voltage waveform at 6 times the AC supply frequency of the AC supply is automatically generated. This waveform is then injected via a injection circuit to give harmonic cancellation.

Abstract: A drive disconnect device is provided in which a drive transfer element (12) is axially movable with respect to input and output shafts (2, 14) so as to selectively disconnect them. A collar (50) is disposed in spaced apart configuration around the drive transfer element so that they do not touch except when the disconnect device is operated to disconnect the drive. When the disconnect operation is initiated, force is provided from a resilient element (56) to move the drive transfer element.

Abstract: A data flow controller comprises two buffers 20 and 22 and a control element 24 for checking for predefined temporal constraints between items of data and for only allowing items of data to be transferred from the first buffer to the second buffer when the data items satisfy the temporal constraints.

Abstract: A generator controller (4) is provided which is able to detect and respond to failure of a generator output voltage sensor, whilst being able to distinguish voltage sensor failure from output voltage collapse due to the presence of an overload or short circuit condition. The presence of a voltage sensor failure is indicated by the measured output voltage being below a first voltage threshold whilst the output current is also below a current threshold.

Abstract: A drive disconnect mechanism is provided where a drive transfer element 12 can be moved to a disconnect position by a hydraulic actuator which itself is controlled by an electrically operated valve.

Abstract: A tagging device comprises a strap attached to a housing. A latch plate is mounted on a first length of strap and a collar is slidably mounted on a second length of strap. The latch plate has two location pegs which fit into holes on the first length of strap such that a hole fits over the lug to make the strap the correct size for a user. Two flexible barbs are formed on the collar such that the collar slides over the plate and the barbs are deformed as they slide up slopes on the plate. As the barbs slide off the end of the slopes they return to their rest position and snap into slots. Moving the collar in relation to the plate once the barbs have snapped into place in the slots causes the barbs to break, giving an indication of tampering.

Abstract: A clamp pressure controller for a variable ratio belt drive system for a generator is provided. The controller monitors the voltage at the output of the generator. If this falls the controller increases the clamp pressure so as to prepare the drive system for the additional torque/force it will be required to transmit. The increase in clamp pressure is rapid so as to prevent belt slip from occurring.

Abstract: An apparatus for determining the statues of a shut-off valve arrangement forming part of a fuelling system of an engine comprises a metering valve arrangement comprising a metering valve member for regulating fuel flow from a pump to the engine and a position sensor for monitoring the position of the metering valve member. The shut-off valve arrangement is operable between open and closed positions and the metering valve arrangement is operable between a maximum flow position, in which the flow of fuel through the metering valve arrangement to the shut-off valve arrangement is a maximum, and a minimum flow position in which the flow of fuel through the metering valve arrangement to the shut-off valve arrangement is a minimum. The position of the metering valve member is controlled by controlling fuel pressure acting on the metering valve member.

Abstract: A disconnect device is provided in which input and output elements 2 and 4 axially overlap and are drivingly interconnected by balls 14 which extend from a recess the radially innermost element into a channel in the radially outermost element. The balls are held in position by a keeper 16 which is axially movable to release the balls and disconnect the drive.

Abstract: A rotor is provided for use at high speed. The rotor comprises a stack of laminations held under compression between opposed flanges. The laminations have a plurality of teeth. Some of the laminations have lugs having passages formed therein through which the bolts that hold the stack in compression pass. The laminations serve to hold bolts against radial deformation at high speed.

Abstract: A drive disconnect device is provided in which input and output shafts are provided in splined engagement. The splines are aligned with the axes of the input and output shafts such that the force acting between the shafts in a separating direction is substantially invariant of the torque being transmitted. The shafts are spring biased to a disengaged position. The biasing force is resisted by a meltable restraining element which is arranged to melt when the temperature exceeds an acceptable value so as to allow the spring to cause the shafts to disengage from one another.

Abstract: The arrangement comprises a stop bar (1) formed from a cylindrical rod having a lengthwise slot therein. The stop bar (1) is secured to a fixed support within an actuator casing (7). A stop plate (15) is slidably secured in the slot and presents upper and lower stop edge portions (16, 17) for engagement with spaced limbs (23) of arm means for converting linear motion into angular motion. The position of the stop edge portions (16, 17) relative to the stop bar (1) is adjustable by means of replaceable shims (21) in the slot.