Abstract: A vulcanizing mold includes an upper mold and a lower mold. At least the lower mold is provided with a cavity in which unvulcanized sample rubber is charged, heated, and subjected to press vulcanization, so as to be formed into a rubber specimen for blowing limit observation continuously changing in vulcanization degree in a longitudinal direction. The cavity is provided with a first cavity that changes in depth in the longitudinal direction and is for producing the rubber specimen, and additionally provided with a second cavity that connectedly extends from the first cavity and is a space in which a temperature sensor is disposed to plot a temperature rise curve of the sample rubber during the vulcanization.

Abstract: A curing characteristics measuring apparatus in which a sample chamber having a fixed surface and a rotation-vibrating drive surface is charged with a sample having a viscoelasticity, a torsional vibration is applied to the sample through the drive surface, a shearing stress generated in the sample is observed as a torque through the fixed surface or the drive surface, wherein mechanism is provided for reducing volume of the sample chamber following volume contraction generated in curing process of the sample.

Abstract: In an apparatus for measuring viscoelasticity, dies are provided in their working face with a plurality of grooves arranged in a radial pattern, each groove cut to increase in width toward the periphery of the die face. Because of this groove design, air bubbles are unlikely to remain in the specimen. In addition, the specimen is far much less likely to slip between the opposed die faces in rotational oscillation generated therein for purposes of measurement, so that reduction in oscillatory angle, lessening of torque and friction disturbances that might otherwise occur as a result of slippage, are prevented. Since the shearing stresses generated in the specimen are transmitted to a torque detection die accurately as torques, precise detection of torque as a function of the viscoelastic stress in the specimen becomes possible.

Abstract: A dynamic viscoelasticity measuring apparatus of torsional vibration type comprising a driving portion for converting a rotary movement to a rotary vibratory movement having a driving shaft having an eccentric end for rotation at an isometric velocity, a driven shaft supported at a right angle to said driving shaft for rotation, an intermediate arm revolving along the side of a cone having a top at the point of intersection of the center line of said driving shaft and the center line of said driven shaft disposed at right angles to each other and a bottom at a circle described by the eccentric end of the driving shaft, and connecting means for operatively connecting opposite ends of said intermediate arm to said driven shaft and said driving shaft and a driving dice for imparting vibration to a specimen, dynamic viscoelasticity of which is to be measured, through said swinging shaft, said vibration having an approximately sinusoidal waveform with complete symmetry.