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21st October 1924
Page 30
Page 30, 21st October 1924 — AN AUTOMATIC TRAILER BRAKE.
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Which of the following most accurately describes the problem?

A Resume of Recently Published Specifications.

AN AUTOMATIC trailer brake is described . in specification No. 208,131, by the Soc. des Trains Chenard et WaIckes, F.A.R. Actually, the brake-operating gear is controlled by a spring, which is always tending to apply the brakes.. It is prevented from doing so -by a rod which is direct coupled to the tractor, and so long as the distance between he tractor and the trailer remains constant, the automatic brakes do not act, for the simple reason that the coupling rod in question persists in holding the brake in the off position against the action of the spring. The draWbar between the tractor and trailer is. a telescopic one, and embodks a stiff spring, which maintains it fully extended, even when the tractor is not actually pulling the trailer.

So long as the drawbar remains in this normal state, the brakes are not applied, but when the resistance of the spring in the drawbar is overcome, as it is when the brakes are suddenly applied to the tractor, or when the trailer commences to try to overrun the tractor when travelling down a hill, then the distance between the tractor and trailer is lessened, the rod which is holding the brakes off is partially released, and the spring in the 'brake gear applies the

brakes. So long as the tractor is accelerating, or travelling at an even pace along the road, the trailer brakes are inoperative, but when the tractor is decelerated, or the trailer accelerated beyond the speed of the tractor, by some external influence, then the brakes are applied.

A Series of Inventions for Improving Vehicle Suspension.

THERE is much that is of interest in the design of spring which is described in specification No. 221,247, by C. If. Littman and J. L. Ardern. The springs are of the kind in which each link comprises two elements which, on light loads, are normally separated from one another for most of their lengths, but which progressively make contact with each other as the load increases, thus automatically stiffening the spring suspension in proportion to the load. Each of these spring units consists of a minimum number of plates, or leaves, bat gives the maximum resiliency, and, at the same time, offers greater resistance to torsional stresses than is possible with ordinary springs. The leaves of the spring taper in width from the point of rigid attachment to frame or axle, as the case may be, to the outer or comparatively free ends. They are in contact at the wider portions, and diverge towards the narrow ends. In the simplest form a unit may consist of two plates, but the principle of the construction is applicable to all forms of leaf spring. Considering the simplest form, and referring to one of the accompanytniillustrations, which shows suoh a spring of the quarter-. elliptic type, it will be observed that the upper leaf is straight, but the lower one is curved. The two plates are in contact at the broad ends of the leaves, and are actually connected by rivets or 018 other means. It is at this point that the spring is anchored, to the chassis. The outer end of the lower leaf is 'attached to the axle in the manner customary with quarter-elliptics, and the two outer ends of the leaves are connected by a shackle of the special design which is illustrated in the sketch. The lower end of the shackle supports the lower leaf on a roller : its upper end embraces the upper leaf, to which it is positively secured by means of a belt which passes through a hole in the shackle and engages a longitudinal slot in the spring leaf. It will be understood that, by moving the shackle lengthways to a fresh position in the slot, the degree of initial tension which is placed upon the lower leaf can be altered.

ANOTHER interesting springing in

vention is described in specification No. 221,425, by J. Gaupillat and E. Thinard. The wheels are independently sprung, in a most ingenious manner, as can be seen by reference to ono a the illustrations on this page. Each is mounted on a stub axle, and each stub axle is carried at the outer end 01 a double-armed lever, the arms being of unequal length, and having the longer arm as the one to which the stub axle is attached. The lever is pivoted on a shaft which runs across the chassis, so that' the one shaft carries the two levers for two wheels. The shaft is supported by a pair of comparatively short quarter-elliptic springs which are attached

to the upper side of the frame of the chassis. The short arm of the lever is attached, at its outer end, through an ordinary shackle, to the outer end of a longer quarter-elliptic spring attached to the underside of the chassis frame, and which curves upwards to meet the shorter one supporting the shaft on which the levers are fulerumed.

IMPROVEMENTS iii cars nowadays

take the form of providing ultra refinement, particularly in the case of such chassis as the Rolls-Royce, and a case in paint 3s exemplified by the invention of F.II. Royce, which is described in specification No. 221,299. It is a protector for spring shackles, and takes the form of an open-ended steel box, which replaces the usual jaw braeket supporting the shackle. The box is bolted to the underside of the frame with one open end presented to the frame and the other facing downwards. Through the sides of the „box are holes to receive and support the ends of the upper shackle pin, about which the shackle swings, with its main part projecting through the lower open end of the box. A suitably shaped member made in halves (which are bolted together) envelops the projecting part of the shackle and the end of the spring. This member fits on the lower end of the box, to which it is bolted,‘ and has a mouth (through which the spring passes) wide enough to allow for the range of movement of the spring. The edge of the month is flanged to receive and hold the end of a leather gaiter which surrounds the spring. Proper provision is made for lubrication of the various parts.

SIMPLE means for dumping the vibra tions of leaf springs are described in specification No. 215,332, by Manufacture Generale de Ressorts. The lowest leaf of the spring is covered by another on which are projections with sloping sides. A spring shoe, in contact with the slopes, and pivoted on a rocking lever, the position of which is easily adjustable, is forced to climb up the slopes as the spring vibrates, and by its pressure upon the slopes tends to damp out the vibrations.

ANOTHER aid to better springing is described in specification No. 221,408, by L. Stas de Richelle. It is a stabilizer, and consists of a double-ended horizontal lever mounted on the axle, and coupled at one end to one side of the triune and at the other to the opposite side.

GREASE guns and oil guns are fre quently found to be inconvenient to refill. Benton and Stone, Ltd., provide, on the oilcan or receptacle, a nipple similar to those which are fitted to the parts to be lubricated and to which the gun is applied when in use, so that, on attaching the gun to the nipple, the cylinder can be filled by drawing its charge directly from the receptacle. This invention, which is referred to in specification No. 221,111, is particularly applicable to the apparatus used for charging oil into spring gaiters.


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