An Albion Preselector Gearbox
Page 54
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PATENT No. 448,356 comes from H. Fulton and Albion Motors, Ltd., South Street, Scotstoun, Glasgow, and
deals with a preselector gearbox and a method of controlling a change of gear by the clutch-pedal movement, The gearbox itself is of the epicyclie type and is illustrated in the drawing at 7. The desired ratio is preselected by the lever (4), but no change occurs until the clutch pedal is depressed. The pedal movement causes a pawl (5) to turn a snail-cam (2), which operates a vacuum valve (1), a snap-action link (10) being interposed to ensure an open or shut position. This cycle results in the gear-change arm (6) being operated by the servo motor (11).
The return to a normal position in readiness for a further change is brought about by two movements. A striker (8) on the gear-change rod meets a similar one (9) on the valve control, and shuts off the vacuum. A trip-arm (3) on the clutch pedal knocks the pawl (5) out of engagement with its cam, so that when the clutch ip reengaged the complete gear change has occurred.
Manufacture of Hardened Piston Rings.
THE high pressures and tempera' tures met with in modern power units, particularly in oil engines, demand standards of high durability from all components, and this is specially true of piston rings. Patent No. 447,932, by Sheepbridge Stokes Centrifugal Castings Co., Ltd., Chesterfield, describes a method of manufacturing cast-iron piston rings having any hardness up to 1,000 Brinell units. This concern states that, hitherto, any attempt at hardening has resulted in not only a deformation of the shape of the ring, but also a loss of resiliency, and the improved method is claimed to avoid these defects.
The proposed method is to mount the slotted rings on a mandrel, with packing pieces in the slots to spring them open to the necessary amount. The whole assembly is then subjected to a hardening process (nitriding is instanced) so that the tensioning and hardening operations take place simultaneously ; this is claimed to produce a ring entirely free from deformation.
The Latest Ricardo Injection Nozzle.
I T is usual to increase the force of the nozzle-closing springs when starting an oil engine, and in patent No. 448,752 044
is shown a scheme whereby this operation is conveniently effected by. a remote control, The patentee is H. R. Ricardo, 21, Suffolk Street, London, S.W.1.
The drawing shows the scheme applied to two injectors, but it may be applied to any extent in a multicylinclered engine. For normal running the needle-closing spring (3) abuts at the upper end against a plunger (2), which in turn is pressed against the end of a screwed sleeve.
When it is desired to increase the spring pressure, the plunger (2) is forced in a downward direction by a second plunger (4), the head of which
is subject to hydraulic pressure from a manually operated master cylinder. This may be situated at a distance, only a stiff piping being required for the transmission of the fluid.
The patent mentions also a single.. cylinder outfit with mechanical control.
A Pre-heated Sparking Plug. DURING cold weather some drivers remove the sparking plugs and heat them slightly in order to facilitate starting, and this same end is the object of a scheme dealt with • in patent No. 446,489 by W. J. Vincent, 17, The Hayes, Cardiff. This inventor suggests the use of a low voltage, internal heating coil (1) positioned around the central electrode of the
high tension system, and supplied from the accumulator for a few minutes before .starting.
The intentor states also that the heated coil will run the engine if the normal ignition should fail, but we should imagine that such operation of a petrol engine would be as irregular as that produced by preignition. He mentions, too, that the plug is also useful for oil engines.
A Simple Injection-pump Control.
Fr() retard the moment of injection for starting purposes is the object of the plunger design, shown in patent No. 448,175 by Robert Bosch, A.G., of Stuttgart, Germany.
The specification states that when starting an oil engine it is usual to place the pump control in the fully open position; at the same time, how-. ever, the injection must be retarded. Hitherto, this has involved a separate mechanism, but the present patent shows a simpler method.
The drawing shows a plunger of the
common type, except for the addition of a small notch (1). The usual operation of such a plunger is as follows :—When the engine is idling, the plunger is turned so that the depth of the helical edge is at its least, whilst partial rotation .lengthens this depth and
gives full injection.
In the present scheme the plunger can be rotated beyond the full-load position; this brings the notch (1) opposite the port.
As the start of injection is governed by the top 'edge, and duration by the depth to the helical groove, it will be appreciated that the foemer is retarded, whilst the latter remains constant.