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AN INFINITELY VARIABLE AUTOMATIC GEAR.

16th September 1924
Page 28
Page 28, 16th September 1924 — AN INFINITELY VARIABLE AUTOMATIC GEAR.
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Which of the following most accurately describes the problem?

A Résumé of Recently Published Specifications.

RATCHETS afford the means whereby C. W. Siddle'rprovides an infinitely variable change-speed gear, wherein the speed of the driven member can be varied by arbitrary 'control, and is also variable, automatically, in proportion to the load on the driven member, below the maximum sceed imposed by the arbitrary control.

According to specification No. 219,434 there is a movable eccentric, mounted on a stationary one which is solid with the driving shaft. The movable eccentric has a ball bearing as a sheave, and, as the driving shaft revolves, the sheave operates a series of cams mounted on the spindles of one-way or ratchet clutches, which are themselves mounted inside the pinions of an epicyclic gear. These pinions transmit the motion to a aunwheel which is keyed to the driven member of the gearbox. That sums up, in outline, the arrangement • of this change-speed gear.

The movable eccentric has the same throw as the fixed . one. Consequently, by altering the angularity of the one . with respect to the oilier, variations in the total throw can be effected from a. maximum of ,twice the throw of either, which is available when they arc acting in conjunction, to zero, which is the throw when they are exactly opposed to. one another. As the amount of the throw is a direct measure of the movement given, on each revolution, to the cams, the method of altering the speed ratio will be apparent. The arbitrary control is through the medium of a quick-threaded screw mounted en the main shaft in the box, so that as a collar on the screw is traversed, by manual means, the angularity of the two eccentrics, one to -another, is altered. The automatic variation is effected by the reaction of the cams on the eccentric rotating it, when the load is great, in a direction to reduce the eccentricity. The automatic action takes place against the resistance of a spring, and the maximum speed ratio is always set by the manual, or arbitrary, means.

Other Patents of Interest.

THE suspension system which is described in specification No. 219,071, by T. Summerson and Sons, Ltd., incorporates coil springs arranged in pairs, of which there are two, one at each side of the frame, to each axle. The springs are vertical, and are enclosed between the top and bottom horizontal member of a collapsable frame, the sides of which are formed by pairs of toggle levers, so devised that the resistance increases according to the shock which the springs have to absorb.

AN interesting invention is the subject of patent No. 219,073, by Aveling and Porter, Ltd., and T. L. A veling. It relates to boilers of the Belpaire type, in which the crown of the firebox is a corrugated plate. The principal object of the inventors has been to design a boiler of this type which can be built of interchangeable parts, capable of being made in the shop, and assembled by unskilled labour. The boiler and firebox plates have machine-finished surfaces near their edges and are drilled to jig. They are riveted to the foundation frame, and the corrugated plate forming the crown and sides is riveted to the bent-over ends of the firebox plates. The latter, after having the crown and sides secured to than, are riveted to the frame, thus forming a complete firebox C48 unit. After this unit is made, the shell plates, which have also machined surfaces near their edges, and are jig drilled, are riveted to the frame. •

A SIMPLE coupling, designed to facilitate the attachment of two-wheeled trailers to tractors has been designed by J. J. N. Sparrow, of Knutsford Motors, Ltd., and the Eagle Engineering Co., Ltd. and is described by the patentees in specification No. 219,086. A jaw-shaped bracket is secured to the tractor, and this carries •a form of Hooke -joint, the other end of which is designed to be attached to the drawbar of the trailer.

THAT form of valve gear in which the drive from the engine shaft to the camshafts is transmitted by a triangular connecting rod occasionally gives trouble when some slight alteration in the centres of the shafts occurs, either on account of expansion or for some other rea.ion. A. Craig . suggests that the coupling means take the form of a Y• shaped piece, sufficiently flexible to accommodate itself to such variations. His design is described in specification No. 219,102.

IN the form of friction-drive gear which is described in specification No. 219,110, by R. Blakoe, the driven discis horizontal, and is carried on the forward end of the propeller shaft casing. The latter is designed to swing in a vertical plane about the rear axle as a centre, thus moving the driven: disc across the face of the driving disc, to effect changes in. the transmission ratio. The driven disc is on the upper end; of a short vertical spindle, the lower end of which carries abevel pinion engaging with another on the front end of the ' propeller shaft.

H C. WEBB AND CO., LTD., propose. that the friction lining for brakes shall be attached to the surface of tlie drum, instead of, as is customary, to the shoes. They claim that by this modification the heat-dissipating qualities of the .brake,are.improved. The invention is described in speeifica• • tiori No. 219,152.

THE equipment detail , for an industrial truck which is

patented in specification No. 219,0'75, by H. W. Howe, is particularly applicable tothose-trucks which are.frequently ' used for the conveyance of articles .which have to be weighed. ' A typical example of merchandise of this kind is cotton, for it arrives at the docks in bales, which, on their discharge ' from a steamer, have to be trucked and transferred to a weighing scale. The lifting of such heavy bales from a horizontal position on a truck platform to the scale, and then back again to the truck after, the weighing, entails heavy manual labour, thus increasing the cost of handling such. cargo. To obviate much of this extra labour this inventor . equips a truck with a supplementary platform at the back, and arranges for it to be hinged to a downwardly projecting extension of the frame. This platform, in its normal position, when the truck is ready for moving, is sloped back, from the vertical, as it appears in the accompanying illustration. It is held in that position by a spring catch. A projecting portion of the platform is horizontal, and very close to the ground, when the platform extension is in its vertical position, which it occupies when about to be loaded, Or when. the bale is about to be weighed. This projecting portion of the platform extends over the platform of the • sca4e, and allows of the bale.lsefng tipped off on to the scale and heels

again with the minimum of trouble. '

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