Polarized Light Dimmer
Page 58
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DATENT No. 829,650' shows a mech anical means of obtaining any desired degree of dimming for dash panel lights. (C.A.V., Ltd., Warple Way, London, W.3,) The device employs polarizing glasses. A pair' of these, apparently both transparent, when placed together can give any degree of light regulation from being • completely transparent to being opaque; this range occurs in 90 degrees of relative movement between the glasses.
The drawing shows a lamp unit in which one polarizing window (1) is fixed to the casing while the other(2) is held in a ring (3) that can be turned by hand. The clear. window (4) acts solely as a diffuser. A ,spring disc. (5) holds the parts in any set position.
• CONTINUOUS-FLOW BRAKE CONTROL
PATENT No. 830,284 refers to powered braking systems in which the braking force is generated hydraulically by obstructing a constantly circulating liquid flow. When this is done, the only path open to the liquid is into the brake cylinders. In the event of power failure, hydraulic accumulators are provided, and the subject of the patent is the control valve for the system. (Clayton Dewandre Co., Ltd., Titanic Works, Lincoln.)
As shown in the drawing, the valve has a port (1) leading to the brake line, a pump inlet (2) and a return pipe (3). The pump inlet is also connected to the brake line. Other ports (4 and 5) lead to the hydraulic accumulator.
The action is not easy to follow on the small-scale drawing. but, in general, the valve is divided into two distinct parts. When the primary plunger (6) is moved by the pedal, it applies pressure to the brake cylinders and operates the secondary portion of the valve to open the accumulators to the developed pressure.
But if no primary pressure occurs, the second portion is worked by further pedal movement. When this happens, the brakes are activated by the stored pressure in the accumulators.
OIL-COOLED PISTON
D ATENT No. 829,971 shows a piston' cooling arrangement in which the cooling oil is fed from a port in the
cylinder wall. It would be used for engines in which oil could not be taken from the supply to the gudgeon pin. (Ricardo and Co. Engineers (1927), Ltd.. 27a Ashley Place, London, S.W.1.) Referring to the drawing, the piston is fitted with a trough (I) joined to a cup (2). lust above the cup. a cross-hole (3) is drilled through the piston skirt. In the cylinder block is a port (4) to which oil under pressure is fed. From this, a small bore leads to the cylinder wall.
At the bottom of ,each stroke the cup receives a charge of oil and the reciprocation of the piston throws it upwards into the trough. Thus, the underside of the piston crown is splashed continually with oil and so cooled.
References are made to two earlier patents numbered 724,354 and 786,985.
TIPPING LARGE TRAILERS
PATENT No. 829,752 shows an articulated tipping vehicle in which the frameless semi-trailer is tipped initially by a hydraulic ram and then by cables pulling against a swinging strut on the tractor. (E. Schronrock, P.O. Box 1543, San Angelo, Texas, U.S.A.)
In .the drawing the semi-trailer is shown in the fully tipped position. The main tipping force is provided by a pulleyand-cable mechanism (1) which pulls the trailer' towards the trac.tor. This movement. is turned into lift by a compression strut (2). When the body is down, the cable lies at an ineffective angle. To overcome this an initial booster is provided; consisting of a hydraulic ram (3) which lifts the body into a position in which the cable can achieve a mechanical advantage.
VEHICLE HEIGHT CONTROLLED A UTOMATIC height control is pro
vided by a scheme shown in patent No. 830;326. It is applicable to suspension'systems employing air springs of the bellows type. (General Motors Corp., Detroit, Michigan, U.S.A.) • The drawing shows the scheme applied to a two-wheeled axle. The axle can rise or fall on radius rods in the' form of parallel links (1). A double beam' (2) is coupled to the frame by a shock absorber (3) at one end, and the load is applied to the beam via air springs (4). The other end of the beam is linked to an air control valve (5) which alters the pressure in the bellows when it is 'displaced from its mid-position.
The patent gives details of the construction of the control valve and of a manually operated valve. By using the latter .valve, the driver can temporarily raise the whole vehicle to clear obstruc:. tions or match-up with loading ramps.
REGULATED COOLING
AHYDRAULIC coupling for interposition in the drive to the cooling fan of an engine is described in patent No. 826,926. The coupling can slip 'and the quantity of liquid in it is adjusted to give an approximately constant speed for the fan irrespective of engine speed. The patent comes from Daimler-Benz A.G., Stuttgart-Untertiirkheim, Germany.
AUTOMATIC HEIGHT CONTROL A SUSPENSION system using air IA springs to give constant frame height is shown in patent No. 830,564 by Firestone Tire and Rubber Co., Akron, Ohio, U.S.A.. The pressure control has a delay action to prevent response to transient deflection.