AN EFFECTIVE AIR STARTER.
Page 19
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Most Air Starters Use the Engine Cylinders ; this One Rotates the Starting Handle.
ANOVEL, and apparently very offs. cient power starter, operatediby compressed air, has recently been placed on the market. in this country by H. H. Square, entinel House, Southampton Row, London, W.C.
The device, which is known as the H-S, is of . French manufacture, and operates on a new principle. Fitted to a vehicle, it takes the place of the starting handle, although a special device embodied in it permits a starting handle to be used at any time, should this be required.
An important consideration is that no alterations have to be made in the chassis. Neil/m.11y the starter is bolted to the cross-bearer which usually carries the starting handle.
There are three main components—a compressor, usually driven by a belt from the engine and provided with a cut-out, which causes it -to cease pnmping when the necessary pressure is attained in a steel cylinder which acts as a. reservoir; a special starter pedal, embodying butterfly valves so arranged that the pressure admitted to the starter is at first moderate and then high; and, lastly, the starter itself, which consists of a neat, almost cylindrical, casting containing two pistons of the same diameter.
That piston nearer the engine acts directly on the starting-dog of the device, and when air is admitted through the starter valve it enters between the two pistons and the inner piston is then driven forward, causing the dog of the starter to engage with that on the engine crankshaft. As the pressuresincreases, the second piStois!is forced, in its turn, to travel along the cylinder, but in the opposite direction. It is, however, rigidly secured to a stout sleeve nut engaging with a square
sectionthread on a central tube secured to the starter dog. This not and piston are prevented from rotating in relation to the main casting, and thus, when the nut moves, the screwed sleeve operating the starter dog is forced to rotate. Im mediately the starter pedal is released, the supply of compressed air is cut off and the interior of the starter put into free connection with the atmosphere, thus releasing the air, when the pistons are returned to their original positions by springs.
To permit of hand starting, a ratchet and pawls are provided at the front end so that a straight-through drive can be obtained. • The starter is made in. various sizes suitable for engines up to 40 h.p. Actually, we saw one of thd 40 h.p. type fitted to the engine of a racing car rated at 75 h.p., which proved absolutely effective in starting this huge engine (which, incidentally, was of the four-cylinder type) from cold.
The prices range from £15 to 240, plus, fitting, and the device should certainly be very useful for municipal work with petrol vehicles, particularly .where a large number of stops has to be made, as the air reservoir permits approximately a dozen starts without recharging, and is automatically refilled within a few moments when tho engine is running. A considerable proportion of the fuel consumed by municipal vehicles is wasted while the engine is running idly during the stops. It would be manifestly impossible to stop and restart the engine by hand every time in the cue of, say, a refuse-collecting vehicle which has to make numerous halts. If fitted with a practicable starter, however, there would be no excuse for this fuel wastage.