Power Clutch Contro
Page 64
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APPARATUS for the control of power-operated clutches forms the subject of patent No. 402,957, from Maybach-Motorenbau, G.m.b.H., of Friedrichshafen, Germany. If a vehic e be running downhill with the engi e idling and the clutch-automatically Ire the driver may require the engine 14r purposes of braking, With most sy tems, provision is made for this, but according to this specification it is necessary to synchronize the speeds of the clutch members before engage-. merit, otherwise the result may be, at the best a jerk, and at the worst a violent skid and mechanical breakage.
rhe method of synchronization described uses two oil pumps of the gear type, one being driven by the flywheel and the other from the clutch shaft. Oil is fed to a closed chamber by one pump and extracted by the other, so that when the rates of flow are equal, no pressure is set up in the chamber. Should tho flows be unequal, a pressure is established ; this works a piston valve which keeps the clutch in the free position until the clutch speeds synchronize; the vacuum is then destroyed and the clutch closes.
Another feature is an auxiliary vacuum cylinder which works the aceeleratot.pedal through a small range in order to speed up the engine and establish synchronization when required. This is operated by the driver using an extra foot button.
A Supercharger-cunt-inlet Valve.
D ATENT No. 403,245, from C. T. Delaney, 81, The Avenue, London, N.W.6, shows a supercharger which
serves also as an inlet valve. The usual method of placing a supercharger on the engine necessitates relatively long passages to the cylinder bead; this, it is stated, requires a high gas pressure in order adequately to fill the cylinders. In this invention the supercharger is placed on or adjacent to, the cylinder head, as shown in the drawing, where a revolving sleeve (2) B50 contains the pump rotor (1), which is of a known type. This sleeve has ports cut in its periphery; these function as inlet valves when rotated over the cylinders in a timed sequence. The pump rotor is so driven that a compressed charge is delivered into each cylinder whtn the port is uncovered.
Owingto the tendency of the explosion pressure to lift the sleeve from its seating, we should imagine some difficulty would be experienced in rendering the joint (9) gas-tight, especially with the high pressures used in compression-ignition engines. Another design is shown in which this difficulty is reduced, but is not entirely abolished.
Isolating the Battery in Accidents.
-La LIMINATION of the fire risk from the electric system in the event of a collision is the object of patent No. 403,087, from the well-known firm, Joseph Lucas, Ltd., Birmingham. This
invention makes use of the momentum of a travelling accumulator -to break the circuit in the event of a collision. In the drawing the battery (3) is housed in a casing leaving a considerable space for movement. Normally, a spring holds the battery up to the contacts (1), which are made so that they
may easily be fractured, A sudden stop would cause the battery to move against the spring, snap the contacts and so isolate the system.
The insulating sleeve (2) is designed to fall down on to the remnants of the contacts and prevent re-connection when the spring recoils.
An Improved Bendix Starter.
AN improved engine-shit-ter mechanism is described in patent No. 401,331 by the Bendix Aviation Corporation, Chicago, U.S.A. The armature shaft of the motor has an epicyclie reduction gear and clutch attached, so that the whole assembly can be bolted direct on to the engine crankshaft. The clutch, which is shown in the illustration, is constructed to allow of a uni-directional drive in order that the engine when started may overrun the motor. In addition, it is of the selfenergizing type, thus allowing a light control element to be used.
The outer drum (1) is attached te the engine crankshaft ; the shoes (2) and their pivots being rotated by the starter. The shoes are pressed into contact with the drum by a conical centre-piece (3) operated by a push-rod which runs through the centre of the armature epindle. This push-rod is so controlled as to engage the clutch shoes by the same action as that which works the starter switch, thus there" can be no jerk caused by meshing a running gear with a stationary one.