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A Combined Infinitely Variable Gear and Shock Absorber.
An ingenious variable speed gear with an infinite number of gradations from direct drive up to infinity is the subject of a patent, No. 116,846, by Pte. Rogers, of the Army Service. Corps. The principle embodied is the use of a' differential gear "and the •Control' mechanical or automatic, of the speed of the planet wheels of this differential gear, the drive being transmitted from the driving. shaft to one eon wheel through the planetary pinions to the second sun wheel, which is actually keyed to the driven shaft. With the planet wheels free to revolve, no power will, of coursp, he transmitted whatever. With these wheels, however, prevented from involving, the drive beComes direct one. These are the limits of control, with an infinite gradation between. The specification is most cinnpIete,"and describes the method of obtaining "a reverse by holding the differentialeease, as well as the means of obtaining different forward speeds. For the sake of aim
plicity we will confine ourselves to the latter, merely stating that the principle involved in obtaining the reverse is the same.
On the spindles of the planetary pinions are mounted eccentrics, the rods from which drive pistons within s,mall oil-filled cylinders or dashpots. Each of these pistons is in communication at both end; by ports, with a supplementary cylinder within which is a second piston,
this piston being mounted on a doubleended piston rod, and maintained in an approximately central position by means' of springs on that rod, one at each end. The springs are compressed between collars on the ends of the rod and the covers of the cylinder. As both cylinders are full of oil, it will be realized that movement of the piston which is secured to the eccentric rod is only possible if a•corresponding movement in the auxiliary cylinder is effected, and this, of course, is only made against the .resistance of the springs. A valVe is provided, however, by which" direct COMmunication can be effected between the two ends of the main cylinder, so that with this valve open absolute freedom of motion in this cylinder is possible. With the valve closed, and with fairly strong springs in the auxiliary cylinder, motion of the main piston becomes practically impossible. Any condition between these two extremes can be obtained Ly, the opening or closing of the valve. This valve is controlled in two ways: by a governor which, at speed, closes it and, as it slows down, opens it or by a hand lever accessible to the driver.
With the valve full open, the pistons and, therefore, the planetary pinions, run .free. The driving shaft then merely causes the planetary pinions to revolve round and round the other sun wheel. This gives title neutral gear. Closing the valve somewhat puts a definite resistance to the. motion of these pinions, and the Poe er commences to be transmitted to the driven shaft at a very high gear ratio. Further closing decreases this ratio and the wagon speeds up. When the valve is closed, the drive is direct; the gear is in 'top."
The value of the device as an absorber of sudden shocks should not be overlooked.
Ransomes' Boiler Improvement.
Ransomes, Sims and Jefferies have patented a construction of steam wagon boiler' the improvement being concerned with the roof of the firebox, which is stamped out so as to embody corrugationa of special form. The specification is No. 117,011.
A shock.absorber is.the subject of No: 116,612, by G. -P. Main and :T. Main.
The Duller-Millikin lock washer is described in specification No. 116,739.
No. 116,993, by S. G. Budd, has to do with detachable and divisible rims for pneumatic tyres.
H. Hodkinson, in No. 116,760, describes a carburetter without a float chamber, the supply of fuel being controlled by the engine suction. • E. Peroldi, in No. 116,712, cools the engine lubricating oil and warms (ho mixture by circulating the former through a jacket round the. induction Pipe, "
. A new .valve.gear is the subject of No. 117,050, by 'T.: D. Taylor : A camoperated piston valve controlling in the main the .exhaust contains an automatic_ inlet valve.