A New /3-ton
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Mobile Crane
AN interesting feature of the new mobile Staffa 2-3-ton crane made by Chamberlain Industries, Ltd., Staffa Works, Staffa Road. Leyton, London, E10, is that it is built on the unit principle. Should any major component call for replacement, a complete sub-assembly can be supplied; accurate
fitting is ensured as the locating holes for any particular subassembly are jig drilled.
The power unit is a NewageAustin industrial-type overheadvalve petrol engine which develops 15 b.h.p. at 1,800 r.p.m. A single dry-plate clutch takes the drive to a four-speed synchromesh gearbox, from which the propeller shaft drives an axle incorporating a differential and doublereduction gear.
Steering is through two close-coupled trunnion-mounted rear wheels which can be turned through an angle of 150 degrees. Braking is on the front driving wheels. The drum dimensions are 101 ins, by 3,1 ins. The brakes are interconnected for both hand and foot operation. All wheels are fitted with 27 by 6 pneumatic tyres.
In addition to two side lamps arid a rear light, there is a spotlight Which illuminates the load at all jib angles.'
The jib is raised and lowered by hydraulic means, a conveniently located lever controlling a valve enclosed in the oil reservoir. An engine-driven hydraulic pump supplies the power. a specially developed non-return valve which is included in the hydraulic circuit preventing damage to the ram unit.
The hoisting mechanism comprises a fan-cooled worm-reduction gear, upon which is mounted the wire-rope drum. Power is transmitted by a propeller shaft and chain drive from a marinetype forward-and-reverse gearbox which is shaft coupled to the engine.
The jib is of lattice design and of riveted construction. It is mounted on an all-welded support frame.
The centre of gravity is unusually low, so that the crane is -fully stable under all conditions.