Abstract: A method of measuring or controlling ozone concentration by ultraviolet ray absorptiometry, includes charging air into a testing tank with its temperature controlled, measuring the disturbing gases generated from testpieces such as rubber samples inside the testing tank by regarding them as ozone, subtracting a value representative of the disturbing gases with a calculation circuit from a value indicative of the preexisting state in the tank to set the ozone concentration at zero, generating a necessary quantity of ozone with an ozonizer by using the zero ozone concentration as a reference point, suspending the generation of ozone after the passage of a predetermined time, measuring once again to obtain a new ozone concentration zero value, adjusting the ozone concentration zero value to the new value if there has been a change in the amount of disturbing gases generated, and repeating at least once the operation described above to regulate the ozone concentration to a desired ozone concentration.

Abstract: A test oven wherein heated air having a predetermined temperature is supplied and the oxygen concentration in the supplied air is controlled. The test oven has a test oven body having an air supply port and an air discharge port, a blower connected to the air supply port for blowing air thereinto, an oxygen concentration detector connected to the test oven body, an oxygen concentration setting control unit connected to the oxygen concentration detecting detector and including an oxygen concentration setter for setting a desired level of oxygen, and an oxygen concentration controller constantly comparing a reference output level generated on the basis of a concentration level set in advance in the oxygen concentration setter with an output level outputted from the oxygen concentration detector and for controling the actual output level to a set level, and at least one oxygen concentration adjusting device.

Abstract: A ventilation regulated hot air supplied constant temperature oven used for heat aging testing. Heated air of a predetermined temperature is supplied to a test oven body through an air supply port. Ventilation of the test oven is carried out through the air discharge port at a predetermined rate at predetermined time intervals.

Abstract: A tension tester in which a specimen marked with at least one measuring marking whose optical characteristic is different from that of the specimen's ground color is held by chucks at the ends and subjected to a tensile load by moving one of the chucks; in which, while the specimen is being stretched, the marking is scanned by a scanner to detect a positional change of the marking in the tensile direction; and in which electric signals which are produced due to the difference in the optical characteristic between the marking and the specimen's ground color are processed to determine the tensile characteristic of the specimen.

Abstract: A tensile testing system for use with a specimen of rubber or other material having a test region defined on its reduced midportion by a marking or markings of, for example, higher lightness than the other specimen surface. The system comprises a scanning device for repeatedly translating the optical characteristics of the specimen or specimens into an electrical signal as the specimen or specimens are subjected to increasing tensile stress, and a gate circuit for deriving from the output signal of the scanning device its portions corresponding to the test region or regions. The varying length of the test region or regions can be represented either by pulse durations or by pulse numbers. The scanning device can be either an "area scanner" such as a television camera or a "line scanner" such as a solid-state line image sensor. Various embodiments are disclosed.

Abstract: A radial ply pneumatic tire, having a high durability, comprising an improved bead portion thereof which comprises a bead wire bundle, a carcass ply of a metal tire cord fabric and a reinforcing ply, all embedded in a rubber matrix, the reinforcing ply having a portion thereof located in the outside surface layer in the bead portion and comprising a woven multifilament fabric consisting of multifilament warps in a density of 20 to 65 yarns/50 mm and multifilament wefts in a density of 20 to 65 yarns/50 mm and an endmost point of the portion of the reinforcing ply in the outside surface layer of the bead portion is located farther from the bead wire bundle than the endmost point of the carcass ply.

Abstract: A pneumatic tire provided with a plurality of slots which are provided in tread grooves and extend in the transverse direction of the grooves but at a suitable spacing from each other for the purpose of confining between the slots the growth of cracks produced in the grooves, so that each crack is prevented from growing up to an extent exceeding the spacing between the slots.