New Time and MoneySavers
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IN the quantity -production of valve rockers for overhead-valve engines, a special machine is required to grind the face which operates the valve. This is of varying radii, and although the amount of metal removed is in the ordcr of only 0.005-0.010 in., the face . must conform accurately to the designer's specification.
A machine designed for this purpose has been produced by Arthur Scrivener, Ltd., Tyburn Road, Birmingham. It employs two grinding wheels, each 20 in. in diameter by 1 i in. wide, running at 1,140 r.p.m. The workpiece in its holding fixture is caused to move downwards and upwards by hydraulic means.
On its downward travel, both radii are rough ground and on the upward movement the finishing cut is given. Once the machine is set, the process is automatic, and removing stock to the extent mentioned, the production rate is 700 pieces per hour,
The Type D.28 battery charger recently introduced by Easco Electrical (Holdings), Ltd., Brighton Place, London, S.W.9, is notable for its handiness and attractive appearance. Wired for 200-250v. 40-60 cis supplies, output is either 12v. at 3 amp. or 6v. at 5 amp. By selecting the 6v. range, 12v. batteries can be charged at I-1 amp.
The case is made of 20 g. sheet steel Bonderized and stove enamelled in yellow. It has a plated carrying handle and the feet are of rubber.
A portable shop crane incorporating a number of interesting features has recently been added to the range of lifting equipment produced by Chamberlain Industries, Ltd., Staffa Works, Lcyton, London, E.10. The fabricated steel base frame, for instance, embraces a set of twin 7-in.-diameter wheels mounted on needle-roller bearings and located in a rotating assembly which can be steered by the towing handle.
By depressing the handle the rear of the crane is raised, making the unit mobile on the wheels, of which there are also two mounted on tubular outriggers. Normally the base frame sits firmly on the ground.
Lifting is by hydraulic power, the hydraulic cylinder being trunnionmounted on the base frame and the piston connected to the rear of the jib. A Staffa Duo two-stage hand pump provides the pressure, and with both pistons in operation, 24 strokes will elevate the lifting hook to the maximum lift of 6 ft. The pressure is 630 psi.
With the larger of the two pistons "out of circuit," 320 strokes give the
6-ft. lift, the pressure being 5,000 p.s.i. I hus it is possible to obtain a quick adjustment of jib height or to lift light loads quickly, or to obtain a slowet lift with the maximum load of 5.000 lb. on the hook.
Premature burning-out of exhaust valves can be a serious matter for the small operator running only one or two vehicles. Special valves may cost a few shillings more than the standard product, but in the long run may pay for themselves. The Farnborough Engineering Co., Ltd., Farnborough, Kent, the makers of Tranco valves, produce a type having what they term an armoured seat.
An addition to the range of products available from Douglas Holt (Est. 1919), Ltd., Holborn, London, is a kit for carrying out repairs in oil lines, fuel tanks, petrol pipes, roofs, and so on. The materials consist of fabric sheeting and a solvent.
A representative of The Commercial Motor repaired a leaky fuel pipe by wrapping a length of fabric, softened in the solvent, over the joint between a flexible pipe and the petrol pipe. The result was in every way satisfactory.
The most recent addition to the wide range of portable electric tools made by Wolf Electric Tools, Ltd., Pioneer Works, Hanger Lane, London, W.5, is a 3-in, electric belt sander, Type BS3, It is a heavy-duty tool and has been designed for continuous operation. The sander belt is 3 in. wide and band length is 24 in. On lieu load its speed is 1,200 ft. per min.
MOST prophecies of technical progress tend to differ from pure prophecy, in the Biblical sense, in that they attempt to indicate the advantages that might be realized in a given time by pursuing certain lines of research, rather than the inevitable results of man's endeavours or shortcomings. This forecast falls into the former category; it speculates on what could be achieved in half a decade or less if the best brains and research facilities in the industry were concentrated on evolving the " ideal " single-deck passenger vehicle for tiSe as a service bus or luxury coach.
It is assumed that there will be no drastic changes with regard to fuel cost or tax and the supply of raw materials, and that operators will still demand a vehicle that will provide the maximum passenger space in the normal dimensions, run economically, have a long life and be easy to maintain.
The development time-limit of five years and the high cost of fuel probably rule out the gas turbine as a potential power unit, although in this period the prototype of a high-efficiency turbine might be developed, with a gas producer in the form of a freepiston compressor. Judging by the results of marine applications in France, the unit would have the efficiency of an oil engine, and the low operating temperature of the turbine would enable low-grade blading to be employed.
The day of the mercury-vapour closed-cycle turbine with atomic firing, used to power a 120-m.p.h. streamlined 90-seater running on super highways, is definitely too far in the future for practical consideration, even if the time limit were extended: The use of integral chassis-body construction provides for substantial weight saving and gives the bodybuilder