A Brake-power Limiting Device
Page 66
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A Resume of Recently Published Patent Specifications That Are Obtainable From the Patent Office, Price is. Each
'ROM Bendix, Ltd., and G. P. 1 Roberts, both of King's Road, Tyseley', Birmingham, comes patent No. 455,788 describing a means for limiting the pull that can be transmitted to a brake mechanism. Several designs are shown, in some of which the tension of the rod or cable is given a definite upper limit, whilst another scheme employs the deceleration of the vehicle as the controlling condition.
This unit, shown in the accompanyitig drawing,. comprises a body portion through which a sliding member (4), forming part of the cable system, may move. The limitation of movement is brought about by a ring of balls (1) surrounding the slider, and housed externally in a conical cup. Normally, the balls are held clear of the cup by a sleeve (3) and the slider can then move freely. In the event of violent deceleration, however, the bob-weight (2) rocks to the right and, taking the sleeve with it, causes the balls to wedge into the conical cup, and thus lock the brake against further application. .
Preventing the Over-heating of Clutch Springs.
TROM Fichtel and Sachs A.G., Schweinfurt, Germany, comes patent No. 455,494, describing an improve meat in the design of plate clutches. The chief novelty is the systematic restriction of the areas in contact in the operating mechanism so as to minimize the transmission of heat to the springs.
The accompanying drawing shows the points at which the principle is applied. The pressure cups of the springs are made with an upstanding bead (4), and the pull-bolts (1) make only a line contact with the operating lingers at point 3; moreover the heads of these bolts are fitted loosely in the pressure plate (2). Whilst the feature of poor heat transmission may form the subject of the patent, there are considerable mechanical advantages to be obtained from this rolling-edge method of construction.
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rmake the adjustment of mixture strength proportional to the engine temperature (assuming this to be a function of time) is the object of the device shown in patent No. 456,228 by J. N. Jarvis, 34, Fairview Road, Oxton, Birkenhead. The device consists of a cylinder containing a spring-returned cup-washered piston. This is connected to the strangler valve of the carburetter, and A set to give a rich mixture in the spring-returned , position, as shown.
An oil-pipe (2) is taken to the engine lubricating system, an adjustable restriction valve (3) being interposed. In operation, the engine is started with the piston as shown, set for a rich mixture. As the engine runs, the oil pressure gradually moves the piston to the left, progressively weakening the mixture, until normal strength is reached. When the engine is stopped, the oil gradually leaks back via an adjustment (4) and thus the potential mixture is slowly richened as the engine cools off. An 'electrical contact (1) serves to operate an oil-pressure warning light.
An Unorthodox Design of Piston. nURABILITY and high heat conductivity are always conflicting claims in the design of pistons, and
many attempts have been made to combine the two properties in a bi
metallic construction. Such a scheme is shown in patent No. 456,190 by the Light Production Co., Ltd., 60-66, Rochester Row, London, S.W.1.
The piston is made in the form of a thin cast-iron or steel shell (2), thickened at the upper end to take the rings. The upper portion is internally screwed with a square thread, and aluminium inserts (1 and 3) are united thereby. A square thread is chosen because it permits of a diametrical expansion clearance without looseness in an endwise direction. An unusual feature is the ball-ended connectingrod, which is held in a socket formed by the two alloy inserts.
Starting Oil Engines on Petrol.
THERE is no doubt that the starting of oil engines during cold weather is often a problem, and a method of facilitating this operation is shown in patent No. 456,107 by Daimler-Benz A.G., Stuttgart, Germany. This concern states that whilst it has been proposed to use a normal carburetter on the air intake for starting purposes, such a scheme has the drawback of unequal mixture distribution, and is subject to_ condensation in the inlet pipe, owing to the low air velocity.
The proposed improvement consists of the provision of an extra smalldiameter pipe (3), fixed midway in the induction pipe, and fitted at the other end with a small carburetter (1) and a heater-coil (2). Control is effected by means of the main throttle arm (4) which also works the small throttle.