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A Hydraulic Transmission

21st March 1958, Page 68
21st March 1958
Page 68
Page 68, 21st March 1958 — A Hydraulic Transmission
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PATENT No. 790,125 discloses a transmission system in which an enginedriven pump supplies fluid under pressure to individual hydraulic motors driving each wheel. (N. Horwood and The Austin Motor Co., Ltd., Longbridge Works, Northfield, Birmingham.)

A general layout of the system, as applied to front-wheel drive, is shown in the drawing. The engine drives a swashplate type of pump (1), the output from which is first led to a change-over valve (2). This is used to obtain forward, neutral and reverse. From the valve, supply and return pipes are taken to the swashplate hydraulic motors 3. one on each wheel.

The patent is concerned principally with the details of the automatic action of the pump. 'Basically this is controlled by a speed-sensitive governor (4) in conjunction with a pressure-responsive unit (5). These jointly adjust the angularity of the swash-plates to give optimum efficiency and a wide variety of load conditions.

WATER INJECTION FOR OIL ENGINES

DEVICES have been proposed for humidifying the ingoing air in a petrol engine and now patent No. 790,071 shows a scheme intended for use in oil engines. (Maschinenfabrik Augsburg-NUrnberg AG., Ntirnberg, Germany.)

In a compression-ignition engine it is imperative that the addition of water should not lower the temperature enough to interfere with self-ignition of the fuel. This objection is overcome by causing the water to be supplied by a separate injection system.

The drawing shows a plan of the combustion chamber in which the air is caused to rotate in a counter-clockwise direction. Fuel issues from the nozzle I and spreads in a thin film over the walls of the chamber. The general shape of the fuel film is indicated by the closed loop 2.

The other two nozzles (3 and 4) are supplied with water and create films which are adjacent to, but separate from, the fuel film. The patent states that the heat for vaporizing the water is taken mainly from the piston crown. If, however, a fuel of low boiling-point is used, it may be an advantage to permit controlled mixing of the fuel and water.

DEPARTURE IN-TYRE DESIGN A DEPARTURE from conventional rx practice in the construction of tyres is disclosed in patent No. 789,770. (Cornpagnie Generate des Etablissements Michelin. Clermont-Ferrand, Puy de Dome, France.) Normally, the sidewalls contain inextensible threads which limit

the expansion caused by inflation. In the present design, however, these threads are absent, and the expansion forces are resisted purely by the stretch of the allrubber or plastics walls. Advantages of the design are said to lie in improved shock absorption and less wear of the tread.

The drawing shows a typical section of a tyre having rubber side walls, as indicated by the heavy cross-hatching. Other typical sections are shown in the specification, some with rather shorter rubber walls having cords extending nearer to the beads. In all cases the beads themselves are provided with the usual inextensible circumferential wires.

A TYRE LOOSENER YR ES that have been in position for some time frequently adhere to the sides of the rim, and patent No. 789,723 shows a tool for freeing them from this condition. (Dunlop Rubber Co., Ltd., 1 Albany Street, London, N.W.1.) A curved tool (1) is the main separating member, being inserted between tyre and rim and pulled away from the centre of the wheel. This action necessitates a fulcrum for the lever, and the remainder of the apparatus is intended to provide this.

A caliper unit (2) is used to grip the far side of the rim, and a chain (3) is hooked into one leg of the caliper. The chain thus forms an inextensible member,

enabling the lever to pivot about the point 4.

If a convenient hole can be found in the wheel, the caliper unit may be dispensed with as an anchorage for the chain.

A NOVEL IGNITION SYSTEM QUGGESTIONS for a new principle in

ignition systems are made in patent No. 789,949 (Siemens-Schuckertwerke A.G., Berlin and Erlangen, Germany). According to the specification, modern engine speeds are approaching the point at which a mechanical make-and-break ceases to be satisfactory, mainly on account of the mass of the moving parts. The scheme proposed uses no masses in the primary interrupter that have to be accelerated, the making and breaking of the circuit being performed by a light ray which varies the resistance of a semiconductor.

The drawing shows the proposed circuit. The high-tension portion consists of a coil (1) and a distributor (2); whilst the primary circuit comprises a light source (3) focused by a lens (4) on to a light-sensitive cell (5).

Interruption of the light ray is performed by a rotary shutter (6) driven in timed relationship with the engine. Interruption of the beam causes the resistance of the cell to rise to such a high value that the current is virtually broken with extreme rapidity.

Instead of a lamp that might burn out, the cell can be triggered by heat radiation, or even by a small piece of radio-active matter.

PLASTICS VACUUM CYLINDERS

PATENTS Nos. 789,871 and 789,872 cover in general the construction of vacuum cylinders for brakes from plastics materials. Various plastics are mentioned, some with a fibrous reinforcement such as glass. (G. D. Peters and Co., Ltd., Windsor Works, Slough, Bucks.)•


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