AN INGENIOUS CHANGE-SPEED GEAR.
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A Résumé of Recently Published Patents.
I T IS CLAIMED for the change-speed gear which is described in specification-No. 194,179, by J. de Cosmo, that it is entirely progreesive, from zero to the equivalent tit a direct drive. No clutch is required on the vehicle which embodies this gear, as the facility with which the zero stage, or neutral gear, can be reached and maintained avoids the necessity for any other means of temporarily. separating the engine from the transmission.
This transmission is similar to one to which reference was made in these columns recently; in that it makes use of free-wheel clutches and a ratchet gear for its operation. The arrangement is most interesting and ingenious. The shafts are the same in number and disposition as those of an ordinary box; that is to' say, there is a main driving shaft, coupled up to the engine shaft by means of an ordinary universal joint. At its inner end this shaft is spigoted into a bearingmounted itaide the main driven shaft. A layshaft transmits the drive from one to the other of these; gearwheels, however, are absent, except
tor reverse. The' transmission is by means of a number of free-wheel clutches —there are eight shown in the drawing-which are mounted on the layshaft. The rotatable part of each free-wheel carries Iwo arms, on one of which is hinged a connecting rod, carrying, at its outer end, a roller, like that on the tappet of an ordinary valve gear.
The main driving shaft carries cams— one for each free-wheel. As the shaft revolves, the cams strike the rollers, and partially revolve the free-wheels. The arrangement of the cams is such that the effect of their consecutive impulses, imparted to the free-wheels, is to give an even rotative Movement to the layshaft, which ia transmitted to the drive shaftby a pair of constant-mesh wheels.
The other arm of each free-wheel is Controlled by springs, so that when any free-wheel is released from the influence of its corresponding cam, it is restored, by means of the springs, to a position in which this second arm makes contact with the underside of a bar. The position of this bar is controlled by what, in this gear, corresponds to the changespeed lever. When the bar is in one extreme position, the free-wheels are all moved so far round, under the influence C48 • of the second arm anal the bar, that the roller on the first arm is quite out of contact with the Cam, and no power is transmitted. This is the zero, or free engine position, of the '• gear. In the c>ther extreme position of the her the movement imparted to the free-wheels by the cams is the maximum; this provides the top speed. Any intermediate position affords a ratio corresponding to 'the movement allowed by the bar.
Other Patents of Interest.
In the driving gear for an electric lightina and starting outfit, which is described in specification No. 193,970, by A. H. Midg ey, ingenious use is made of the end thrust, which is generated when a helical too.lied wheel is used, to operate an automatic clutch. The mechanism is particular y useful in connection with single-unit combined lighting and starting motors, of the type in which the starting motor is required to drive the engine at a reduced speed, but is itself required to be driven at engine speed when running as a dynamo.
A sun-wheel on the motor shaft is in constant mesh with a planetary -pinion mounted on a plate which is–on the engine shaft. On the same spindle as the pinion, and arranged to revolve wish it, is another, having helical teeth. The latter is in engagement with a ring, which is slirlable in either direction, and
which, when .moved one way, engages, as a cone clutch, with the plate on which the other planetary pinion is mounted, and when moved in the other direction engages with the gear casing. The teeth cf the helical pinion are .set sp that, when the motor is driving the engine, the movable ring is slid, under the pressure of the teeth, to make contact with the fixed casing. This involves a reduction in gearing between motor shaft and engine shaft. When the engine drives the motor, the reverse movement takes place, and the drive is a-direct one.
A simple anti-dazzle device is described in specification No. 194,029, by J. L. Conway. The reflector is in the form of a paraboloid, in which the rear end portion is hinged to the body of the refleetor.; The important feature appears to be that the bulb is disposed under the hinge.
The carburetter improvement which is the subject of specification No. 193,932, by Brown and Barlow, Ltd., relates to that type in which the pilot jet has two delivery conduits, one of which delivers on the engine side of the throttle and the other on the rear side.. So soon as the throttle is opened, both conduits deliver to the engine. The feature of this -present construction is that the two conduits and the jet are carried in a. .part of the carburetter which may easily be removed from the rest.
Specification No. 194,009, by F. A. Sclater, describes en electrical heater for the incoming mixture, arranged to fit between the carburetter and the engine It has an electrical resistance in the form of a grid, extending completely across the passage for the gases. The feature of this invention is that the fitting embodies an additional air-inlet device, the air from which passes over the heating grid as it is admitted.
A rather ingenious method of controlling the compression ratio of an engine is proposed by C. A. VandervelL The cylinder is provided with a substantial liner, which is in connection with convenient coupling rods and levers outside the engine, by which this liner may be raised and lowered within the cylinder. The device is described in specification No. 193,948.