Under The Tread (1934)

in the manufacture of Brunswick tires each cord is drawn from its individual spool guided by thousands of tiny eyelets the cords are carried through a specially conditioned room where the temperature and moisture are strictly maintained to preserve full strength and elasticity of the cords the manufacture and processing of the insulated cord construction is far more costly than the processing of ordinary thick fabric here each cord must be held in positive position until it passes through huge calendars and formed into a wide sheet of ply stock containing 1,800 cords thoroughly and evenly coated with a special rubber compound rubber use for this ply stock is so compounded that it possesses high anti friction properties which give further protection against internal friction and where the angle of the chords in the ply stock is an important factor in the life of the tire because a definite angle is necessary to give proper balance to the body plies in order to ensure the correct angle and exact width applies this enormous cutting machine is used accurate to a fraction of an inch the strips are carried to the tire room individually on an immense system of conveyors another important part of attire is the bead the wire used as a breaking strength of 280,000 pounds per square inch each strand is thoroughly insulated with a special rubber compound then automatically formed into a circular band the spliced ends are taped and on another machine are covered with a special rubberized fabric this fabric covering is called the flipper it's used to anchor the bead to the body of the tire another long safe mileage feature of Brunswick tires is its famous safe and efficient tread in order to produce this top wear resisting thread stock seven different ingredients are blended in with the highest grade of raw rubber obtained of each ingredient is accurately weighed before it is mixed in the huge Banbury mixing machines these machines mix 800 pounds at a time and then dump the batch to a conveyer belt which carries it to a series of large cylindrical rolls called mills for further mixing with additional compounds these Mills not only mix the roller but needed as well much as bread dough is needed before baking another mill heats and prepares the sock cutting it into a large thick continuous ribbon before it is fed into a machine which forms it into proper shape in width and thickness here it begins to look something like a tire tread as it travels along a 300 foot conveyer to be cooled weighed in check a special compound of adhesion gum is next applied and thoroughly rolled onto the underside of the raw tread strip this layer later becomes a part of the double shock absorber unit which provides the positive adhesion between the tread and the carcass at the end of this long conveyor is an automatic cutting machine which measures out and cuts the thread stock into the exact length required for different sizes tires further check however is made on the weight of each strip of tread stock to assure proper balance to the tire if the weight is offer a fraction of an ounce the strip is rejected in the tire building room the components are assembled plies beads flippers tread stop finishing strips and double shock absorber units made ready for tire builders skillful operators with years of training and with equipment of the most modern type this cylindrically shaped machine is called a drum each ply is rolled accurately and smoothly into place one fly at a time a system of rollers shaped applies to the drum and press out all air pockets between the Flyers in order to produce positive union of all parts of each flyer after the second Flyers roll down the beads are placed on each side the flipper strips surrounding the beads are securely fastened to the edges of this second fly and the edges of the body fabric are are left over the beads locking them firmly into the body of the tire the additional Flyers of cord fabric are then added one by one until the carcass is completely built up and prepared for the trade stop one of the most common causes of premature tire failures and blowouts is a separation of the carcass in the tread in order to eliminate this hazard Brunswick has developed the double shock absorber unit that's the center unit being applied it consists of two extra layers of core materials treated and coated with a special cushion compound which not only ensures positive adhesion of carcass and tread but also protects the body of the tire from high speed road shocks by absorbing and distributing them over a wide area of focus double shock absorber is an exclusive Brunswick feature and found only in Brunswick super service tire the two black strips at the sides are chafing strips they protect the lower side walls of the tire from rim shaping and keep the flexing action of the sidewalls evenly distributed above the point of rim contact the thick top tread stock is next placed smoothly and evenly over the entire carcass the ends placed securely together it is rolled firmly and pressed to the caucus by the rollers at the bottom of the drum when it's removed from the building drum it's in the form of a hollow cylinder doesn't actually look like a tire till it's shaped in the forming bugs now here the tire is prepared for the mold a heavy rubber tube called a water bag is placed inside the assembled tire in the falling box a quick application of heat and the tire is shaped to fit the curing moles in the curing of a tire heat and pressure should be applied uniformly to the inside as well as the outside of the tire otherwise the rubber coating of the inner Flyers would be of a different consistency than the rubber of the art applies with the Brunswick hydro curing process the tire receives a thorough even cure throughout because after the tire is placed into the mold and the top hat the mold clamp down it's lowered into a huge boiler or vulcanizer and the fitting is attached to the water bag inside the tire 28 molds are placed in each vulcanizer each mole fitted with a water connection a hydraulic ram gradually lowers the mold at their place the water fittings interlock forming a pipeline when the vulcanizer is closed water at a temperature of 300 degrees Fahrenheit and that a pressure of 240 pounds per square inch is forced in the water bags inside the tire at the same time steam temperature of 300 degrees Fahrenheit is applied to the outside of the moves in the vulcanizer the temperature and pressure of the water in the water bags the steam in the vulcanizer the hydraulic pressure on the RAM and the curing time are all accurately controlled from one central point by automatic regulation slow baking process gives an even cure throughout the tire and induces full adhesion of carcass and tread not obtained where air is used in the bag and the curing is done from the outside of the molds Allah as soon as the tires are cured they're cooled by flushing the molds with cold water to prevent any possibility of over curing removed from the vulcanizer x' to a long conveyor system the moles are cracked open and the tires removed in a finishing room there strayed with tire paint trademark striped and balanced then put through a rigid inspection test in spite of the thoroughness the constant check during each phase of manufacture every tire is thoroughly inspected inside and out no blemish or imperfection is overlooked every tire must check with the exacting specifications set for it specification set by one of the most outstanding groups of research engineers and chemists in the industry in the research laboratory there's a constant quest for the better than best day after day the search for new developments and product innovations is diligently carried on anticipating the needs of tomorrow new formulas new compounds are developed in a miniature of Factory toy like in comparison to the huge equipment of the plant but exact in detail are the been very mixing machines Mills calendars and vulcanizer here small experimental batches of rubber are carefully compounded mixed in miniature Mills rolled into sheets on small calendars and cured in tiny ovens samples of these cured sheets of rubber compound are tested for their strength stretch elasticity and resistance to wear every new compound is also tested for flexibility and it's resistance to heat set up by friction plier stop is experimented with and studied just as thoroughly each component part receives its share of attention samples of cord are weighed and flexed on specially constructed devices both before and after they're conditioned in experimental evidence stretch and braking points of cords are constantly being checked and charted on tensile strength machines this laboratory checks not only experimental materials but samples of all raw materials used in production as well sections of carcass Incred welded together or vulcanized by various experimental methods and compounds are flexed and tormented by specially designed flexing machines to determine their it easy' properties other tensile strength machines are used for a full test to measure the number of pounds necessary to tear the tread from the carcass this test proves the positive adhesion attained in Brunswick super service tires by the double shock absorber unit not only on a coal full test for on heat tests as well there's a section of the laboratory known as the torture chamber it's aptly named because a tire that will run this gauntlet of tire destructing mechanisms and survived truly earns its right to be called one of the finest tires ever built here is a brunswick super service inflated to a pressure four five six times its regular inflation point pressure is forced into it until it bursts the men conducting these tests are protected by heavily insulated partitions pound by pound water is forced into the tube under pressure inflating the tire to two hundred pounds or more until something must give under this terrific pressure the steel bead snapped but the tire itself did not blow out another device is used to test the possible injury to a tire as a result of hitting into curbs or road obstructions a tire is mounted on a heavily weighted steel rim and dropped on an iron cleat this is repeated many times with a tire at many degrees of under inflation in an effort to penetrate the protecting wall at the double shock absorbing unit on a sprague machine the audrey tire doesn't last very long because here is a test that compares only with the continuous run at incredibly high speeds over the roughest possible roads for thousands of miles without a stop the tires have forced against a large dynamometer wheel at car load weights the rough surface provides traction for the tires which pull against the dynamometer load heavy iron cleats fashion to the large wheel pound the tire incessantly throughout the run for the equivalent of thousands of miles these tires had driven all on and on for days at a time imagine the heat generated in the tires with an incessant pounding the cleats and every part of a tire pounding and flexing about 2,000 times a minute the heat of the run expands the air inside the tire forcing even greater pressure against the dynamometer wheel under these conditions an ordinary tire soon fails but the Brunswick Super Service when put to this test proved definitely its resistance to destructive high-speed flexing by running continuously for the equivalent of 10,000 miles without failure comparative tests are made against competitive tires to determine the degree of heat set up inside a tires when run on the Sprague machine Thermal coughing's are used to measure the internal heat setup under varying degrees of speed and load pressure and tires that are built with pick fabric plies show a much higher temperature under the tread then the Brunswick super service with its insulated core construction even when running heat rooms where the temperature is kept at 115 degrees Brunswick super service tires have passed the straight test with no sign of failure but the most dramatic test of all is the piledriver here a heavily weighted steel wedge is suspended over the tire guided by a smoothly polished and greased runners it's drawn up at all shaft height of 90 feet that's the height of a 7-story building when this steel wedge reaches the top it's released gathering tremendous velocity in its downward plunge this destructive force strikes the tire with terrific impact sometimes rebounding 30 feet or more no ordinary tire can possibly withstand this fire driver test after each test in the torture chamber the tires are sent to the dissection room of the laboratory the tires are cut down fly by ply and studied for possible signs of injury or failure if a tire fails the cause of failure is immediately determined the final test of a tire is on the road under actual operating conditions Brunswick is one of the few companies in the industry that maintains a large fleet of test cars and trucks this test fleet proves conclusively the long safe mileage built into Brunswick tires day after day week after week Brunswick tires are subjected to every condition of road surface and speed over smooth highways uphill and down over rough roads and bumps a few drivers ever encounter accurate records of mileage and speeds are diligently kept the tires are shifted and rotated around each wheel every 300 miles so that where conditions are uniform now these tests are continuous with time out only for refueling or a change of drivers running 24 hours a day carrying on through the night in all kinds of weather these tests are ultimate proof of the performance quality and safety of Brunswick super service tires

Channel: US Auto Industry

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Id: sRwS6A2u_FY

Length: 16min 17sec (977 seconds)

Published: Wed Sep 30 2009