A DEWANDRE IMPROVEMENT.
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A Resume of Recently Published Patent Specifications.
A LIIERT DEWANDRE, in his sped±1.fication No. 241,154, describes an addition to his specification No. 228,670, for the now well-known brake which hears his name. The point aimed at in the present invention is to provide the driver with a means by which he
can " feel " the amount of pressure he is exerting on his brakes.
The main features of the Dewandre are already so well known that it is only necessary here to give particulars of the recent improvement. The usual foot lever is mounted on a shaft which runs crosswise on the chassis. A slotted bellcrank lever actuates the vacuumregulating valve by means of a pin projecting from the pedal lever, and the rod shown. The larger of the two pistons applies the power to the brakes by means of the piston rod, which slides through the smaller piston and is connected to the lever which carries the brake cable. The vacuum pipe communicates from the source of vacuum to the part of the cylinder between the two pistons, and the effect of suction is to draw them towards each -other. The smaller piston is provided with a connecting rod which is attached to the pedal lever, as shown.
The effect when working is as followi :--zA movement of the pedal sets up a communication with the source of vacuum and the cylinder, which has the effectof tending to draw the pistons together; but, owing-to the fact that one piston is smaller than the "other, the power elected by the pistons is unequal. The larger piston operates the brake direct; whilst the smaller one exerts a comparatively slight pull on the pedal
lever. This pull, although less than that exerted on the brakes, is in exact relation to the braking effect being exerted at any time.
A New Lock-nut.
IT is strange that, considering the number of lock-nuts offered to the makers of motorcars, some of which have possessed real merit, one sees practically nothing but the castle nut and Grover washer in general use. For the vital parts such as steering joints, where failure might result in laSkl of life, there is perhaps nothing better than
the usual practice, but for many parts where a split-pinned nut is not desirable, there should be. a good opening for a nut that, when tightened, will grip its bolt so that it becomes " spanner tight."
Such a nut is shown in the specification of William Youlien, No. 249,179.
This nut is extremely simple and should practically cost no more than the ordinary nut. As will be seen from the sectional view, there is a groove formed near to the face on which the nut tightens down, and the underside of the nut is slightly convex. The effect when the nut is tightened firmly is slightly to crush in the convex face, which has the effect of closing the lower threads on to the bolt, and at the same time altering the distance of the threads in this part with those in the upper part of the nut, which still further tends to tighten the nut on its bolt (See our issue for April 20th.) We have had an opportunity of testing these nuts and find that they do ail that the inventor claims for them. This nut can be run down its bolt freely by the fingers and, after tightening, can only be turned round by a spanner, and even then requires some effort to loosen it. We suggest no better place to test such a nut than the attaching of a front mudguard stay to the frame of a commercial vehicle running on solid tyres.
An Anti-carbon Fuel.
THE Canadian Electro Products Co., Ltd., of Montreal, in their specification No. 249,348, describe a fuel which they claim will not cause the deposit of carbon to form on the heads of cylinders and pistons. They claim that by the use of their mixture of fuel, engines can run for long periods without necessitating the cleaning off of carbon deposits. Various proportions of the substances mentioned are suggested, but briefly, the invention is as follows 1—" It has been discovered that if an unsaturated hydrocarbon gas, such as acetylene gas, and an aldehyde, such as acetaldehyde and notably paraldehyde, which will diffuse readily in and make stable solutions with liquid hydrocarbon fuel, be added to gasoline or a similar hydrocarbon fuel, the accumulation of carbon when the fuel is burned is substantially eliminated."
A Japanese Invention.
IT is hard to realise what rabtoring in Japan can be like if the invention of Shinkichi Nisbida and others, of Tokio.
is any indication of the state of the art
in that country. The inventors seriously claim as a useful addition to a ear the following safety arrangement: The ear is fitted with a buffer which, whenever the driver runs into a pedestrian, releases two sprag-like members which point forward and which drop on the ground and stop and lift the car up so that the victim can be easily removed
from under the vehicle. Mention is made of the automatic and simultaneous application of the rear brakes.
No mention is made of any proposals to extricate the occupants of the car from the glass of the windscreen which they will certainly go through if the sprags,are dropped while the vehicle is travelling at high speed.
A Brake Invention.
THE Compagnie d'Applications Mecaniques, of France, in their specification No. 228,154, show a brake of the expanding type. It will be seen that in the main this brake is of ordinary design so far as the shoes and the earn for expanding them go: -Reference to the drawing will show that the expander cam is at-the bottom, w-hilst at the top willbe seen what. is" claimed as a novel point in the form of a cam for the purpose of expanding the shoes to • facilitate the adjustment. A cam is provided with a worm and wormwheel (not shown here), Iwbieb can revolve the cam so as .to push the sliding members apart and so widen the distance between those joints on which the shoe hinges, and so to adjust the brake for wear, Unless we are mistaken, we have seen such a cam employed in recent de
' signs of brake. We think, however, that the employment of some means of adjusting a brake from the hinge end of the shoes will become a general prac tice. After careful reading we are still in the dark as regards some points, and think that something plainer than the following sentence might be written : "The arrangement of the adjusting member and the shoes being such that components of the re actions of the bearing parts of the adjusting members upon the bearing pares of the brake shoes tend to force the bearing parts of the brake shoes in the same direction as that of the strains of ,the said shoes due to the application of the brakes."