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Resilience

MRPRA-Wallace Data Computer - R3

Introduction

The resilience of rubber is calculated as the ratio of rebound height of a mass to drop height. Numerous designs of apparatus have been produced including the Lüpke Pendulum and the Dunlop Tripsometer.

All are subject to errors due to air resistance, friction in moving parts, vibration in the apparatus and whip due to elasticity in solid pendula. All require a considerable degree of operator skill if acceptable results are to be obtained and all are tedious to operate.

The ratio of rebound height to initial drop height is equal to the ratio of the kinetic energies after and before impact. This in turn is equal to the square of the ratio of velocity after and before impact. Thus by measuring the velocity immediately before and after impact the resilience can be readily computed.

Velocity is measured as the time taken for a small vane to pass a sensor. By using a small vane the effects of acceleration and deceleration are insignificant.

Resilience expressed as a percentage is displayed The readout display is held until cancelled by the operator. Sensing heads can be supplied to attach to most resilience testers.

A remote 'Reset' press-button is supplied to allow the Data Computer to be positioned away from the resilience tester.

Lupke Pendulum

If the Data Computer is used in conjunction with a Wallace Lüpke Pendulum a Remote Release Solenoid' can be supplied which will release the pendulum when the 'Reset' button is pressed.

Dunlop Tripsometer

If the Data Computer is supplied with the Dunlop Tripsometer then modifications can be made enabling the solenoid brake to be released when the 'Reset' button is pressed.

When a Data Computer is used on an existing Tripsometer the 'Reset' button has to be pressed first followed by the existing brake release button.

Specification

See the table below for a run-down of this product's specifications.