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A Five-speed Transmission

25th October 1957
Page 68
Page 68, 25th October 1957 — A Five-speed Transmission
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PATENT No. 782,389 shows a fivespeed and reverse gearbox suitable for a heavy vehicle. The primary drive is through a torque-converter which is used in conjunction with an epicyclic

gear, the whole being built into a unit construction. (Borg-Warner Corp., 310 South Michigan Avenue, Chicago, Illinois, U.S.A.) The drive from the engine enters via two paths, one directly through the flywheel and the impeller (1) with its shaft, the other being through the driven turbine (2). . Each ratio is automatically brought into action by engaging and/or releasing one of the friction clutches (3 and 4) and the brake bands (5, 6 and 7).

A feature of the scheme is that for fourth and fifth speeds the torque is diVided, about 35% 'passing through the • fluid coupling and 65% direct. A large spur gear (8) is provided for mating with the .pinion of a power take-off. Two built-in oil 13-Limps provide the power for hydraulically operating the clutches and controlling the amount of fluid in the torque-converter.

A TORQUE CONVERTER LOCK

P'ATENT No. 782,338 refers to transmissions comprising a torque-converter in series with a gearbox and incorporating a clutch operated by a servo-motor. When the gear lever is moved, electric contacts actuate the clutch and cause the gear to change. (Fichtel and Sachs A.G., Schweinfurt am Main, Germany.)

In the case of heavy vehicles, it is often necessary to start the engine by towing, or to use it as a stationary brake. The inclusion of a torque-converter in the drive would prevent this, and the essence of the patent is an automatic device that Locks the torque-. converter solid at speeds below the idling speed of the engine.

The drawing shows the device which is very simple in principle. A ratchet-toothed disc (1) is attached to one part of the torqueconverter and an outer ring (2) to the other. Spring-loaded pawls (3) connect the two parts when at a standstill, but as soon as rotation commences they are thrown out centrifugally into an ineffective position. To prevent shock by sudden engagement of the pawls, the hub of the ratchet mechanism is driven through a clutch (4) which will transmit only about 40 per cent, of full engine torque.

A PISTON-RING ALLOY

PATENT No. 781,027 discloses a new formula for an alloy suitable for casting pistnn-ring blanks in sand moulds, In .addition to iron, a typical alloy contains 3.5 per cent. carbon, 2.2 per cent. silicon, 1 per cent. manganese, 0,7 per cent. copper, 0.06 per cent. phosphorous and 0.1 per cent. sulphur, with the possible addition of a very small quantity of tellurium not exceeding 0.05 per cent. (Regie Nationale des Usines Renault, 8-10 'Avenue Emile Zola, Billancourt, Seine, France.) A CRACK-DETECTING MACHINE AMACHINE designed for testing PA crankshafts, camshafts and similar shapes for cracks is disclosed in patent No. 782,074. (E. Bartlett, 6 Grace Ro ad, Aylestone Park, Leicester.) The workpiece is first magnetized and then covered with " magnetic ink" which is a finely powdered iron suspended in oil. Any cracks present show up as thin black lines.

A general layout is shown in the drawing. A pair of wound bobbins (l) is provided with V-blocks in which the workpiece (2) is placed. The magnetic circuit comprises the bobbin cores, the workpiece and an adjustable iron base (a). The

flow of magnetic ink is provided by a motor-driven pump (4), .

For the test, direct current is used, supplied by a transformer and rectifier. After test, the bobbins are switched to AC. which demagnetizes the workpiece. The chief subject of the patent is this switch-over for the purpose of demagnetization.

A NOVEL TRAILER COUPLING MPROVED. coupling arrangements for heavy-duty trailers such as earth scrapers are shown in patent No. 782,387, the object being to make the coupling transfer extra weight to the tractor in circumstances conducive to wheel slip. (Sentinel (Shrewsbury), Ltd., Whitchurch Road, Shrewsbury and L. Hamblin.) The scraper front axle swivels about the axis of the king-pin (1), it also pivots about A horizontal pin (2). The swan-neck (3) forms part of a subassembly and it too pivots about the king-pin.

A tow bar (4) is pivoted at the points 5 and 6, and connects the assembly to the tractor. In parallel with the towbar is a pair of hydraulic rams (7). By expanding or contracting thege rams, it is possible to transfer any desired proportion of the axle weight to the tractor. .

If, even with maximum added weight, the tractor should still dig itself in, the rams can be used to extricate it.. To achieve this, the upper drawbar is disconnected and the rams extended to their full length. The tractor then

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