A NEW HIGH-CAPACITY GARAGE TYRE PUMP.
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A NEW electrically driven compressor, 13-known as the David, on account/ of the ease with which it deals with giant tyres,. has been designed by Messrs. 'William and James, of Gloucester. This consists of a .9 b.h.p. electric Motor adaptable to any voltage of direct or alternating current, from the shaft of which is driven a horizontally opposed twin-cylinder air compressor, capable of inflating an 815 nun. by 105 mm. tyre in AO secs.
The crankshaft is direct coupled to the armature' spindle of • the motor, whilst phosphor-bronze connecting rods couple it to the cast-iron pistons. Mechanical lubrication is used, surplus oil being returned to the motor bearing sump. An aluminium cooler and filter purify the air, whilst an automatic release valve, which can 15e set to blow off at any requiredpressure between 1 lb.and 150 lb. per sq. in., obviates the continual reading of the pressure gauge, although this is also fitted.
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Eighteen feet of pump tubing are carried on .a fixed drum and 30 ft. of fleiible cable are stored on a revolving -drum provided with slip-ring contacts, so that no more cable than is necessary need be unwound, the whole installation being earthed to conform with Borne Office regulations.
The motor may be controlled by, a turn-button switch in close proximity to the pressure gauge and release valve, a table of recommended tee pressures and loads being prominently displayed.
The complete outfit is mounted on a hardwood trolley with • rubber-tyred ;-mheels, a brake being automatically applied when the handle is released. ft is claimed that, when using this apparatus to inflate a set of 815 mm. by 105 mm. tyres, more than 7d. can be saved as compared with the Use of a foot pump, tile relative times taken for the work being 2 mins. 40 secs. and • 40 mins. Apart from this pumping a large tyre is most fatiguing work.