Abstract: A capacitance fuel-gauging probe is supported at its upper end in a fuel tank by a stress-relieving mount. The mount includes a disc assembly formed of two identical steel discs each with a central aperture. The discs are joined together at their respective outer edges and around their respective central apertures by steel rings which separate the discs from one another, forming an annular recess. The ratio of the estimated disc stress to the disc material proof stress, and the ratio of the estimated probe stress to the probe material proof stress are substantially the same and as small as possible. A bolt extends through the aperture, the probe being clamped to the center of the disc assembly by a nut. The outer edge of the disc assembly is clamped securely with the wall of the fuel tank by a collar screwed into a sleeve within which the disc assembly is located. Any vibration of the probe during use causes flexing of the disc assembly so as to damp the vibration.

Abstract: A radiation pyrometer for a gas-turbine engine has a fibre-optic cable with three discrete bundles. At one end of the cable, the bundles, are arranged in a jig with one bundle being positioned centrally, being the other bundles which are of C-shape and located on opposite sides of the central bundle. A converging lens focusses radiation from the turbine blades onto the end of the cable, the ends of the bundle being oriented such that each bundle receives radiation from a different region spaced along the length of the blades. At the other end of the cable, each bundle is connected to a respective detector.

Abstract: A warm-air hand drying installation has a floor-mounted pedestal with several drying apparatus around its periphery. A single fan supplies air to each apparatus via a central duct when any one of the apparatus is switched on. Each apparatus has a flap valve and a heater. The valve covers either the outlet of the apparatus or a side opening into the pedestal. When any one of the apparatus is switched on, the heater is energized and its valve opens to allow air flow to its outlet and onto the hands of the user. The heaters of other apparatus are not energized and their valves remain positioned such that air flow to the apparatus is directed internally between the pedestal casing and the duct, to the fan inlet. In this way, air flow can be maintained constant regardless of the number of apparatus in use. The fan remains on for a time longer than the heater.

Abstract: A control circuit is connected between a three-phase power supply and a motor and ensures the correct application of phase signals to the motor, regardless of the way in which the control circuit is connected to the power supply. A first output signal of the supply is connected directly to an input of the motor via the circuit. Supply of power to the other two inputs is controlled by four switches, two of which receive signals from the second supply output and have their outputs connected to respective motor inputs, and the other two of which receive signals from the third supply output and have their outputs connected to respective motor inputs. The switches are controlled such that two switches are on, and the other two switches are off if the third output signal is positive with respect to the first output signal when the second signal passes through zero with respect to the first signal in a positive sense.

Abstract: A pyrometer for viewing the blades of an engine has a forward lens which produces a first image of the blades in an image plane P.sub.1. Rearwardly of the image plane P.sub.1 is an assymetric faceted lens assembly having a central region with a long focal length, and an outer annular region of shorter focal length. The outer region of the rear lens assembly forms a second image of the first image in a second image plane P.sub.2. The inner region forms a third image of the forward surface of the first lens in the second image plane P.sub.2. A disc mask is fixed centrally to the forward surface of the first lens, and an annular mask is located in the first image plane P.sub.1. The forward end of a fibre-optic cable is located in the second image plane P.sub.2 and comprises a central bundle of fibres which receives the second image, and two outer bundles which receive different parts of the third image.

Abstract: A method and apparatus for mounting a video type display tube (20) in a given dynamic mechanical environment employs a plurality of mounting members (56, 56a, 56b, 56c) which are secured to the periphery of the tube (20) at four corresponding predetermined static and dynamic reaction points (1,2,3,4) where substantially minimum bending and torsional stresses occur for the mounted tube (20). Elastomeric grommets (53,54,52a,54a,52b,54b,52c,54c) having a predetermined dynamic stiffness over a desired temperature range capable of attenuating the associated dynamic G forces of the dynamic mechanical vibration and dynamic mechanical shock in the given dynamic mechanical environment are mounted in opposing pairs in an aperture (60) in each of the respective bracket members (56, 56a,56b,56c).

Abstract: A tracheostomy tube assembly has a tube the forward end of which is located within the trachea and supports an inflatable sealing cuff. The rear end of the assembly supports a soft, semi-flexible flange having slots which receive a tape by which the assembly is secured about the patient's neck. The assembly also carries a second inflatable plastics cuff mounted on the flange, which encircles the tube and has a raised portion on opposite sides of the tube. The volume of the second cuff, when inflated, is sufficient to accommodate the space between the flange and the neck without elastic deformation of the cuff.

Abstract: A radiation pyrometer has an inner tube with a lens mounted in a rear portion which is stepped to a forward portion of reduced diameter that is open at its forward end. An outer tube extends coaxially around the inner tube and is separated from it by an annular gas passage. The outer tube has an aperture at its forward end that is smaller that the external diameter of the forward end of the inner tube and larger than the internal diameter. The outer tube has gas inlets into the passage which are located rearwardly of the forward end of the inner tube, the area of the gas inlets being greater than the gap between the forward end of the inner tube and the outer tube. Gas flows through the inlets, along the passage, across the forward end of the inner tube and out the aperture, thereby setting up a substantially constant pressure in the rear portion of the inner tube and reducing the entry of contaminants.

Abstract: Heat dissipation from electronic modules is improved by clamping their edges against heat-conducting fins in a housing by means of two expanding jackscrews. Each jackscrew has a shaft mounted in bearings in the module and carries a row of alternate closed rings and split rings. The closed rings are smaller in diameter than the split rings and have a circular section. The split rings are of tubular shape, having ends of circular section which engage the closed rings. The forward end of the shaft is screw-threaded to engage a fixed nut in the housing. When the shaft is screwed into the fixed nut, it pulls a connector on the module into engagement with a cooperating connector in the housing. At the same time, the closed rings are forced against the split rings, causing them to expand radially and exert a clamping force against the edges of the modules, forcing them into thermal contact with the fins in the housing.

Abstract: A surface-mounted electrical connector, or other contact assembly, has an insulative housing which supports one end of contact pins, in two rows, one above the other. The other end of each contact pin is bent back beneath itself to extend along the lower surface of the housing in channels separated from one another by walls. The lower end of each pin has an enlarged spherical knob which contacts a respective conductive region on the surface of a printed circuit board. The roofs of the channels are rounded to receive the knobs, the height of the channels being substantially the same as the diameter of the knobs. The rear end of each contact pin is inclined downwardly, in its natural state, to project below the housing, so that it is urged resiliently into contact with the conductive region during mounting. A bolt helps secure the connector to the board.

Abstract: An actuator assembly has two actuators mounted back-to-back such that their actuator rods are displaced in opposite directions. Each actuator has a spring embracing the rod between two slidable collars. The spring urges the collars apart towards stops on the rod and stops on the actuator housing, so that, on failure of the actuator, the rod is displaced to a central position. The rod is driven by a motor which also rotates two discs of different diameters. Each disc has a notch in its edge which align only at the central position of the rod and allow a roller to drop into the notch. When the actuator fails, a solenoid releases a locking arm which engages the rollers, keeping them in the notches thereby preventing rotation of the discs and displacement of the rod.

Abstract: An electrical connector for surface mounting on a printed circuit board has a rectangular plastics housing with two rows of contact pins. The pins are each in the form of a turned metal wire of circular section having an enlarged spherical knob at its rear end. Each pin extends parallel to the base of the housing, having its rear end bent downwards so that, in its natural state, the knob lies below the housing. When mounted on the circuit board, each knob is resiliently urged into contact with a respective printed contact pad on the board and is secured thereto by solder. The forward end of each pin provides a male member that makes connection in a socket in a cooperating connector.

Abstract: A tap for a urostomy or similar bag has a first valve member which includes a male valve element located in a cap. The cap has at least one drainage hole. A second valve member including a tubular female valve element is engageable with the male valve element to close the tap, but is disengageable from the male valve element to open the tap. Flexible and/or extendible diaphragm or sheath is secured to and encloses part of the female valve element in a fluid-tight manner and is also connected to the cap in a fluid-tight manner. The diaphragm or sheath permits relative movement between the two valve members.

Abstract: The inner unit of a gyroscope is of circular shape and is formed with an inclined outer edge at one end. The inner unit slides within an outer casing having a transverse end face at one end. An annular recess of triangular section is thereby defined between the inner unit and casing which receives a ring of resilient material. During assembly the inner unit is urged against the end of the casing, to compress the ring within the recess, by reducing pressure within the casing. The inner unit is held in position, with the ring compressed, by soldering an end plate to the casing. The pressure within the casing can then be returned to normal.

Abstract: An electrical contact element for a backplane connector is of unitary construction. The element has a compliant portion of generally cylindrical shape with tapered ends and is formed with at least three radial slots equally spaced around the element, the slots intersecting one another within the element and extending axially along the element. The radial slots open into one another within the compliant portion and form three sector-shaped limbs that are urged inwards towards one another when the contact element is inserted into a plated hole in a circuit board. Below the compliant portion projects a narrower stem with flattened sides for a wire wrapped connection. The other end of the contact element is formed with a female mating portion in which may be mounted spring-wire contacts for engaging an inserted pin.

Abstract: An aircraft head-up unit includes a collimator that is automatically swung upwards out of the pilot's ejection envelope by an actuator, driven by gas pressure from an ejector seat mechanism. The collimator is supported by a first frame, and the actuator is supported by a second frame on which the first frame is pivotally mounted. The frames are held in position by spring detents, which can be overcome by an upward or downward impact. The collimator has a concave surface bearing a holographic element and is mounted below the pilot's line-of-sight, with a CRT display. A reflector, mounted above the line-of-sight, reflects a display image from the CRT display, through a combiner, to the collimator. The collimator reflects the display image to the combiner which directs it into the pilot's line-of-sight.

Abstract: The output of a capacitance fuel sensor is supplied to two switches that are controlled by a switching control unit. The two switches are opened and closed in synchronism and antiphase with one another, and in quadrature with the drive voltage applied to the sensor. The output of one switch is supplied to the input of a first integrating current-to-voltage amplifier which in turn supplies a signal representative of fuel quantity to a fuel indicator. The output of the other switch is supplied to another integrating current-to-voltage amplifier which in turn supplies a signal representative of the quantity of contaminants to a contaminant indicator.

Abstract: A hybrid CRT display includes vector generated portions for alpha-numeric data and normal raster scan portions for symbol data. A deflection yoke for a CRT is driven by a single horizontal amplifier having switching means which operate the amplifier in three modes necessary to achieve the hybrid display, enhanced by resonant retrace during raster scanning.

Abstract: An altimeter has four display panels each being a matrix array of light-emitting diodes. An energizing unit energizes selected diodes to produce a representation of a number in each panel indicative of the value of the input. A knob on the altimeter selects input signals from a barometric source or a radar source. When barometric signals are selected, the altitude is represented in the panels by bright numbers against a dark background. When radar signals are selected, the energizing unit changes the format of energization of the display to represent altitude by dark numbers against a bright background. Other formats are also possible.

Abstract: An accelerometer has a tubular coil that surrounds coaxially a cylindrical magnet. The magnet is polarized along a second axis transversely of the common axis of the coil and magnet. A sleeve of soft-iron surrounds the magnet and coil to provide a magnetic return path, the sleeve having two vertical slots which receive bearings. The bearings are carried by a shaft that extends across and above one end of the coil so that the coil is supported for angular displacement about a third axis orthogonal with the common axis and the second axis and displaced from the second axis. An optical pick-off mounted below the other end of the coil is used to sense rotation about the third axis, by detecting displacement of a portion of the former on which the coil is wound.