582 



THE INDIA RUBBER WORLD 



May 1, 1921 



MACHINES FOR RETREADING AND REGROOVING 

 SOLID TIRES 



REPAIRERS AND USERS nioum because the solid tire does not 

 lead itself to repair as does the pneumatic. In other words, 

 retreading — that is, attaching a new tread, slipping in new 

 sections and all ordinary air-tire repairs, arc not done. Never- 

 theless, the bis tires arc rctrcaded. but by cutting away the worn 



Firestone Solid-Tire Grooving Machine 



outer surface and getting down to a new unworn one. So also 

 the double or treble grooved tire, if worn down or ground down, 

 must be regrooved. 



For this purpose, several machines are employed. What is 

 known as the Firestone machine is shown in the accompanying 

 illustration. This employs a V-shaped knife A which is forced 

 against the tire by means of a lever B swinging on a bolt in a 

 steel standard fastened to a wood base. A can C bolted above 

 the knife allows water to drip on the blade to facilitate cutting 

 the rubber. While forcing the knife against the tire, the operator 

 steadies the machine by standing on the wood base. This very 

 simple and compact tool has been in effective use in many solid 

 tire applying stations. 



Another machine for trimming and grooving worn solid truck 

 tires has a wooden base, recnforced with angle iron to prevent 



Boucher's Solid-Tire Trimming and Grooving Machine 



vibration, and is movable on steel wheels controlled by a handle. 

 The knife on the machine is so designed that its tendency is to 

 sharpen itself rather than to get dull with use. Four tires can 

 be trimmed with it in fifteen minutes.' The motive power of the 

 truck is used for turning the rear wheels when the latter are 

 presented to the trimming machine, but the front wheels are 



turned by hand. When the machine is set against a solid tire • 

 and the latter is revolved the turning of the crank at the side 

 causes the carriage holding the knife to travel transversely on 

 the tire, cutting its surface perfectly flat. The motion is reversed 

 with a crank on the opposite side. The depth of a groove can 

 be delcrmined and then made by first setting the carriage and 

 turning the crank at the end of the machine, the crank being 

 connected with an adjusting screw at the end of which is the 

 knife. The machine weighs 100 pounds. 



It is claimed that with this device, the life of many solid tires, 

 ready to be discarded because badly cupped and flattened, can be 

 greatly prolonged and a service offered solid tire owners that has 

 often been unobtainable. — Atkin & Boucher, 8414 South I'igueroa 

 street, Los Angeles, California. 



A NEW SHOCK ABSORBER 



The wide use of automobiles for pleasure touring has 

 created a great demand for shock absorbers to smooth out 

 the roughness of country highways. Metal shock absorbers 

 or combinations of metal and liquid, have been found of little 

 use in improving the spring action of the car as a whole. 

 Air shock absorbers have usually been somewhat impractical 

 because of voluminous receptacles and high air-pressure. 



The newest shock absorber "J. H. — AR" (a-r or air) com- 

 bines the metal with the pneumatic spring in such manner 

 as to take away from each kind of spring its disadvantages 

 and to produce an auxiliary spring with no after-vibration, 

 as it possesses the power of checking its own oscillations. 

 The construction includes a ring made of spring band steel 

 which is inserted between the existing laminated spring and 

 the frame of the chassis in place of the shackles. This ring 

 supports an air spring consisting of a cylinder ball containing 

 a rubber air cushion and a piston working against it. The 

 cylinder is clamped to the upper part of the ring and the 

 piston to the lower by means of flanges. 



The distribution of work in this 

 shock absorber is such that 

 the spring ring carries the 

 greater and the pneumatic spring 

 the smaller part of the load 

 to be supported. If there 





667 A» 



Wl' 



The "J. H. — AR" Pneumatic Spring 



is no air in the rubber air cushion the ring will be nearly 

 closed. By pumping air into the rubber air spring the upper 

 part of the auto body is lifted into its normal position, which 

 balances the car. By increasing the air pressure according 

 to the weight to be carried the metal spring can always be 

 kept in its open position and it is thus possible to give the 

 shock absorber its original resistance. There are no frictional 

 parts, therefore the absorber does not require lubricating 

 bolts or grease cups. The simple action of the piston com- 

 pressing the air in the rubber cylinder ball absorbs all shocks^ 

 — W. A. Wetterwald Co., 160 Fifth avenue, New York, N. V. 



