SENTINEL BRAKES AND STEERING GEAR.
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A Résumé of Recently Published Patents.
ONE of the mential features of a l/power-braking system is the provision of some means whereby the driver i.e • able to appreciate, in sonic proportion, the degree of retarding force which he is applying. If he merely opens a cock or valve, allowing the pressure of some fluid, or a vacuum, to beecanc effective; he has not that knowledge.
Several methods of ensuring that he actually feels, through his hand or foot, same resistance which is a measure of the extent to which the brakes are actuathy being applied, have been -tie.vised.• The object is to reproduce as nearly as possible, the pressure between foot and pedal, or between hand and lever, snail as is experienced by a driver when applying a mechanically operated brake of one -of the more usual sorts. One such device has already been patented by B. E. Alley, in connection with a brake operated., by fluid pressure: he now, in
• patent specification No. 215,079, describes a means of obtaining the same effect in connection with a vacuum. brake.
The means provided are incorporated in the valve which canards the operation of the brake. The mechanism, as it is deseribecl in the specification, is particularly applicable to steam wagons, and a steam ejector is used to create-the neoe'ssary vacuum. A small ejector is, mcimted in conjunotion with the brake controlling valve, which is actually a small piston working in a vertical cylinder, and having a rod coupled direot to the operating pedal. In the side erf the rod a cam is formed, and in contact with the cam is the stem of the valve whieh controls the supply of steam to the ejector. The parts are Sr set that, as the pedal is depressed, the steam is allowed to enter the ejeetor, creating the vacuum.
There are two ports in the wall Of the piston-valve cylinder, one communicating with the ejector, the other with the brake-operating mechanism. The former is lower than. the latter, so that ite is covered first; the latter is so high that it is never quite closed by the piston even at the top of its stroke. When at the top, the piston strikes the stem of a valve in the cover of the cylinder, opening the valve to the atmosphere, and breaking the vacuum. .
Pressureupon the .brake pedal lowers the piston valve and its rod. The latter opens the ejector, valve, in proportion to its movement, thus creating a proportional degree of vacuum above the piston, which vacuum is felt by the driver as a pressure between his foot and the pedal, thus affording the -desired reaction.
ANOTHER invention by the, same
patentee, is described in specification No. 215,111. It is concerned with steering gear of a type with which we arc familiar en Sentinel wagons. In that type of gear the shaft to which .the Steering wheel is secured is threaded at its lower end, the thread engaging with a nut carried in the end of a, lever.' As the steering gear is .operated, and-the lever moves, the shaft swings a little out of its central position,' and for that reason i.a held, at the top of the steer
3348 ng column only, in. bearings designed to allow of that oscillatory movement. Ii the construction covered by this patent the steering box is designed to serve as an oil reservoir; the spherical bearings are particularly simple in their construe-. lion, and the provision for oiling thern is such that any surplus flows into the box.
.Other Patents of Interest.
THE invention of A. Fortiiii, which is concerned with the operation of fourwheel brakes, needs no fewer than throe .patent specifications for its complete de scription. Tim first of these specifications, No. 196,578, embodies the prin-Ciple, that of operating the front-wheel brakes by means of the rear-wheel brakes, or vice versa. The brakes of the Operating set in either case, are mounted on a floating bracket which, when the brake is that applied, partially rotates, following the movement of the drum, and in its movernem pulls upon a rod which is coupled to'llie brake expander lever of the other set of brakes.
In the second specifieaticm, No. 197,294, the principle is applied to diagonal braking, the brake of, say, the off-side rear wheel operating, in the Manner
already described, that on the near-side -frcint wheel, While that on the near -side rear wheeloperatesthe brake on the ail-. side front wheel.
In the third specification, No.207,780). simple .provision is made to ensure that these brakes shall operate with equal_ effect, whether the vehicle is travelling in a" forward or backward direction. To make sure that some braking effort will be avaiia.ble in the event of failure of the coneection between the operating set of brakes and the other, 'a limit is set to the, movement of the floating bracket to which the operating set is attached, and, When that limit is readied, the bracket cranes' against a stop, and the brakes of the operating set only are expanded and applied in the ordinary way:
IN the descriptien of an interesting
• design of collapsable top for a closed body in specification No. 214,643, by the Daimler Co., Ltd., it is pointed out that hoods for this purpose, when made collapsable, soon lose their shape and good appearance in side elevation. The object of the present invention is to obviate this difficulty. The sides of the hood are attached to 'longitudinal rails whieh, when the hood isia4 be collapsed, fold: hi a horizontal direction; the hood then folds back and; with these rails and the rear pillar, collapses into-7' a horizontal
position, being tiered in a small rear quarter of the hood.
SIMPLIFICATION of front wheel brake-operating gear, of the type ensbodying a shaft, supported at one end on the axle, and at. the other end upon the frame, and having flexible and telescopic joints, is described in specification' No. 214,819, by llentley Motors, Ltd. In this construction the cross-pin of the flexible joint at the frame end of the shaft is extended to form the operating lever Of the gear, thus reducing the num.her of parts necessary.
THE improved form of brake cam which is patented in specification No. 203,696, by Lancia and Co.. is best understood in reference to the aceom
panying drawing. The " cam" embodies twe. pins on which are rollers which come into contact with staggered projections on the Shoes, tha•location of pins and projections being such as to increase the effective leverage of the brake gear. In one with the oam-piece are stops, which make contact with the sides of the projections on the shoes when the brake is off.
INGENIO, US is the method of provid
ingignition for an. internal-combustion engine which is described in specificatim No. 212,636, by if1 E. Fellows. A glowing wire, initially heated by electricity, and subsequently maintained at the right temperature automatically, is the source of ignition. This wire is lOcatecl in a small chamber,which communicates with the •interior of the engine cylinder through a. narrow passage. The gases have to be driven through this passage before ignition can take place, and timing of the ignition point is effected by diverting some of the gas into auxiliary compartments.