Abstract: An introducer along which a laryngeal mask airway can be slid into position has an open, curved channel portion shaped to extend, in use, from a mouth of a patient to the region of the patient's pharynx. At its machine end, the introducer is bifurcated into two arms extending along opposite sides of the airway, the thickness of the arms being sufficient to protect the airway from damage by the patient's teeth. The arms are curved in an opposite sense from the curvature of the channel portion so that they extend over the upper lip of the patient. A curved bridge piece extends between the two arms and lies against the skin between the patient's nose and mouth.

Abstract: A power supply system has two power supply generators connected to respective power buses, to which various loads are connected via relays. A monitor unit has a store with information about the thermo-electric performance of the generators and information relating the power drawn from the generator to the time for which that power can be drawn safely. The monitor monitors the power drawn from each generator and the time for which it is drawn and disconnects a load when power is drawn at a level and for a time that exceeds a safety limit in the store. The monitor reconnects a load when the power drawn from the generator and its thermo-electric performance indicate that this can be done safely.

Abstract: An electrical supply system with two power generators and several items of electrical equipment has a processor that controls disconnection of the equipment if demand should exceed supply. The processor has a hardware switch controlled by outputs from the generators. The processor runs two different programs at the same time but the switch supplies only one of these to the output. When equipment needs to be disconnected, the switch changes to supply the results of the other program to the output and this effects the disconnection. When sufficient supply is restored, the switch changes back to its original state to supply the results of the first program to the output of the processor.

Abstract: A patient transfer trolley has a pivoted top mounted at the upper end of an hydraulic support column of adjustable height. Two hydraulic cylinders connected to one end of the table top are connected to respective hydraulic pumps mounted at opposite ends of the trolley base so that angle of the top can be altered and either end can be put into a Trendelenburg position. A third pump is connected to both the support column and the cylinders for adjusting the angle of the top. An overpressure valve diverts pressure from the third pump initially to the cylinders for adjusting the angle so that the top is returned to a horizontal position. The valve then opens to allow pressure to flow to the support column and raise the trolley top.

Abstract: An hydraulic lift system has an actuator connected to an hydraulic circuit, having a pump, via a supply line. A balanced seated valve is connected between the supply line and a reservoir, the valve being controlled by a solenoid and an electric drive unit. The drive unit supplies a gradually increasing or decreasing voltage to the solenoid to open or close the valve gradually. The valve has a valve member that is displaceable along its length and has a valve head of frusto-conical shape. A passage along the valve member balances fluid pressure across the valve member. The solenoid has an armature with a pole face that can be displaced towards a fixed pole face to unseat the valve member. The pole faces have complementary frusto-conical surfaces and there is a non-magnetic washer between them.

Abstract: A power supply system for controlling supply of power to several inductive loads has a power monitor and a processor that determines when power consumed exceeds the capacity of the system. When overload is detected, hardware rapidly disconnects loads of low priority. A software register is loaded with software controlling staggered reconnection of the loads when power capacity becomes sufficient again. If capacity is sufficient, all the loads may be reconnected at the same time.

Abstract: A dual lane computing system has at least one processor in each lane, each processor having an associated store which stores input data supplied to the processor and their time of arrival. The lanes produce nominally-identical outputs which are supplied to a comparator that detects when there is a discrepancy between the lanes. When a discrepancy is detected, an external processor is loaded with software that simulates the operation of the lanes. The data in the store associated with one of the lane processors is supplied to the simulator processor in respect of the input just prior to the detection of the discrepancy. The simulator simulates the operation of one lane utilizing this data and its output is compared in the comparator with the actual output of that lane as recorded when the discrepancy occurred.

Abstract: A compliant contact for insertion in a plated hole in a circuit board is machined from a single piece of metal with a shank at one end, which projects through the hole, and a socket at its opposite end, which can be crimped about a conductor inserted in it. Rearwardly of the shank, the contact has an entry region with two convex surfaces tapering away from one another rearwardly to a compliant region. The compliant region has two flat sides and a slot extending between the sides, which divides the region into two resilient blades, each of which has a flat, parallel outer surface. The flat outer surfaces are divided from the flat sides by turned edge portions formed as a part of a common surface of circular section.

Abstract: Electrosurgery apparatus has a processor that generates a data stream output representing the characteristics of the electrosurgery pulses to be generated. The data stream output comprises digitally-represented values indicative respectively of the width of each pulse, the duration of a first period during which pulses are to be generated, the duration of a second period during which pulses are not to be generated, the duration of a third period during which pulses are to be generated and the duration of a fourth period during which pulses are not to be generated. The data stream also includes digital instructions as to whether or not the electrosurgery output is to be cut only and whether it is to include spray coagulation. Three switch control units receive the data stream and provide outputs to three switching circuits, which provide two monopolar and one bipolar output. Each switching circuit includes a transformer connected to receive the outputs from the switch control units.

Abstract: A patient trolley has a top that can be raised and lowered hydraulically. A guide wheel mounted on a resilient suspension is coupled to the trolley top so that, when the top is raised, the guide wheel is also raised and, when the top is lowered, the guide wheel is lowered into contact with the floor.

Abstract: An ultrasonic fuel-gauging system for an aircraft with three fuel tanks has probes in each tank connected to dual-lane data concentrator circuits. The digital outputs from one lane of the data concentrator circuits are supplied to respective tank circuits, the outputs of which are connected to two input/output circuits. The outputs of the other lanes of the data concentrator circuits are connected directly to one or the other of the two input/output circuits. The tank circuits and input/output circuits are processors of identical construction programmed with different software. If a tank circuit or input/output circuit should fail, its function is taken over by reconfiguration of one of the remaining processors.

Abstract: A monitor for the return electrode of electrosurgery apparatus has three contacts in a socket that connect with two or three contacts on a plug connected to the return electrode. One pair of contacts in the socket is connected across an oscillator that provides an output to a first primary winding of the transformer when there is a low impedance between the contacts.

Abstract: An electronic assembly has a substrate with several conductive tracks and with a switching matrix within the thickness of the substrate. Several groups of identical integrated circuits are mounted on the substrate, one circuit from each group being operatively connected into the assembly by the switching matrix. A processor detects malfunction of a circuit and controls the switching matrix to disconnect that circuit and operatively connect into the assembly an alternative circuit from the same group.

Abstract: A transfer trolley for transferring a patient onto an operating table has a removable patient support platform divided across its length into two parts coupled by a hinge. A rod and cylinder mounted at their ends to respective parts of the platform are lockable to lock the two parts of the platform and prevent bending at the hinge while on the trolley. The trolley has two arms for supporting the platform, which either extend laterally under the platform on opposite sides of the hinge or longitudinally and traversing the region of the hinge. A control unit on the trolley has infra-red emitters that emit signals to sensors on the table, to control operation of the table, only when the trolley is correctly located for transfer.

Abstract: A ramp generator has an integrator, which provides a ramp output, and a counter, which counts a clock signal during the rise period. The counter and clock are arranged so that when the actual rise time is equal to the desired rise time, the counter overflows and returns to zero. If the rise time is too slow, the counter will contain a count at the end of the rise period. A register is connected to receive this count and an adder adds the contents of the register to the contents of the adder repeatedly each time a clock pulse is generated. The adder has an output connected to the input of the integrator and, each time the adder overflows, supplies a correction pulse to the integrator so that its rise rate is increased.

Abstract: An epidural connector has a housing in two parts, one of which contains a resilient, compressible slug with an axial bore into which an epidural cannula is inserted. The slug has a hexagonal external shape with flats separated from one another by rounded corners. The inside of the first part of the housing is of circular shape so that gaps are formed between the slug and the inside of the housing. The second part of the housing is screwed into the rear of the first part and has a female bore for receiving a male coupling. The forward end of the second part of the housing engages the rear end of the slug so that the slug can be compressed about the cannula and deformed into the gaps to accommodate cannulae of different diameters.

Abstract: The handset of electrosurgery or welding apparatus has two spaced contacts which make connection with the shaft of an electrode that is insertable into the handset. A low power alternating signal generator is connected to the forward contact. When the electrode is fully inserted into the handset and contacts the rear contact, the alternating signal is supplied to a detector. The detector is connected to a power generator and rams it on when the alternating signal is detected so that electrosurgery power is supplied to the forward contact.

Abstract: A marine radar has a screen on which is displayed a radar image and several representations of the different control functions of the radar such as range, gain and sea clutter setting. The radar also has a key pad with three keys and a tracker ball that is connected to the radar control unit. The control unit generates a marker on the screen that is movable by the tracker ball. To change one of the control functions, the tracker ball is displaced until the marker moves into the region of the representation of the appropriate control function. The control unit then produces three boxes on the screen below the control function to indicate the different options available for that function. The user can select the desired option by pressing the appropriate one of the three keys.

Abstract: A catheter has a tubular plastics body and an insulated metal wire extending along the bore of the catheter through an aperture close to its patient end. The exposed end of the wire is covered by and connects with an electrically-conductive plastics material injection molded about the tubular body to form an electrode with a convex surface projecting from the surface of the catheter.

Abstract: Electrodes 11 and 12 in a cold-cathode discharge lamp have a row of holes 13 arranged side-by-side along their length. The holes are formed by laser machining and extend at an angle of between about 25.degree. and 35.degree. to the normal, the holes in the two electrodes being oppositely inclined.