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Power Assistance for Hydraulic Brakes

11th April 1952, Page 58
11th April 1952
Page 58
Page 58, 11th April 1952 — Power Assistance for Hydraulic Brakes
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Which of the following most accurately describes the problem?

A HYDRAULIC brake in 1-1 which the manual effort is amplified by a vacuum servomotor is described in patent No. 666.364, by A. B. Kristenson and Grahs, Stockholm, Sweden. A feature is the .method of maintaining manual control should the servo system fail to operate.

The drawing shows the servo-cylinder and its associated mechanism. The pressurefluid from the manual master41inder arrives through pipe and is led to a hydraulically operated suction control valve shown at 2. In operation, the applied suction causes the servo-piston (3) to move left and work a second hydraulic cylinder (4), the output of which is led to the wheel cylinders through Pipe 5.

The flow from the manually operated cylinder is also led to the auxiliary master-cylinder by pipe 6 and the conical valve-seating (7). Normally, the servo-piston, as soon as it moves, closes this valve, and the piston does all the. work, but if this shouldfail the driver's master-cylinder would remain in working conimunicatiqn with the wheel brakes.

RUBBER SPRINGS FOR INDEPENDENT SUSPENSION

DA TENT NO. 663,694, describes a

suspension system in which the resilience is provided by a vaned member embedded in a solid mass of rubber. Deflections of the vanes thus distort the rubber which then acts as a spring, The patentee is A. Laisne, Nantes, France.

The drawing shows (left) the general layout of the scheme, in which the wheel is mounted on a swinging arm having a shaft ball-journalled at 1 and

n40

2, and passing through a rubber block (3). The rubber members are clamped by flanges (4) which are rigidly attached to the chassis. The shaft carries a vaned member (5) which is gripped in the

rubber. Movement of the vane is resisted by the rubber which thus provides variable-rate springing.

A BATTERY-SERVICING TOOL

TO clean a dirty or corroded battery stub and the clips is never an easy job. A special tool, shown in patent No. 666,719 by Thomas Meldrum, Ltd.. Freedom Works, Sheffield, 2. enables this to be done with ease and without using several tools.

The drawing shows the tool, which needs little explanation. A spiral reamer (I) is used to clean out the taper bore of the clips, whilst the battery ends can be trimmed by a box-cutter (2). The latter unit has a spring-loaded scraperblade, so that it can accommodate the two sizes of battery terminal. The tommy-bar is formed at one end into a ring-spanner (3) for undoing the clip nuts, whilst the other end is made into a general-purpose screwdriver (4).

A NEW TWO-STROKE ENGINE rlA DESIGN for a two-stroke engine is shown in patent No. 666,507, by Texaco Development Corporation, of New York, U.S.A. The engine uses both high-pressure fuel injection and sparking-plug ignition, and is said to be capable of running with a compression ratio of anything between 4 to 1 and 10 to I, the latter being preferred. It is also not critical with regard to fuel; it will operate on any grade of oil between the limits of bestquality petrol and light lubricating oil, with or without pressure-charging.

The two valves (I) in the head are both for exhaust purposes, the air inlet consisting of a ring of ports (2) which are uncovered by the piston at bottom stroke.

The air ports are located tangentia ly, so that a vigorous swirl is imparted to the air, which persists during rie compression stroke. An injector (3) sprays tangentially down.

stream of the swirl, and a sparking-plug is located just behind it at 4.

In operation, fuel injection commences anywhere between 75 and 30 degrees before top dead centre, and ignition occurs immediately afterwards so as to fire the mixture as soon as it becomes combbstible.

AUTOMATIC BRAKE ADJUSTMENT

, A SIMPLE scheme for maintaining a constant clear-ance between shoe and drum is described in patent No. 666,342, by Girling, Ltd., Tyseley, Birmingham, 11. The scheme is applicable to any type of brake. The two shoes each abut on the back

(1) of hydraulic cylinders, the plungers (2) of which operate the other shoe. In addition, alongside each shoe is fitted a lever (3), pivoted at 4 on the back-plate, and carrying a small facing (5) of friction material at its free end. These levers always rub lightly on the drum, being held in place by hook-like abutments (6) carried on the shoes.

When the shoes are operated, each lever, although pressed harder on to the drum, gives way because of its springiness. After releasing pressure on the hydraulic cylinders, the levers recover and withdraw the shoes from drum contact, the clearance being determined by the movement of the .; spring in the levers. The springs (7) I counterbalance shoe moment.


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