Measuring instrument with automatic loading and an automatic cycle, for studying the tensile characteristics of fibres

In a measuring instrument for measuring the deformations of and tensile forces in a sample fibre or analogous material when subjecting the sample to a longitudinal tensile stress and which comprises a frame, a tensioning means carried on the frame and including a movable element to be associated with one, movable, end of the sample and a force detector also carried on the frame and including means to be associated with the other, fixed, end of the sample, the improvement in that the said instrument comprises a feed plate;

• a plurality of pairs of sample blocks with the sample blocks of each pair being provided with means firmly to hold opposite ends of a sample to be tested;
• a sample loader provided with means to receive a plurality of said pairs of sample blocks stacked with the samples carried thereby parallel one with the other, said sample loader having a discharge axis perpendicular to the direction of extent of said samples and being held fixed relative to the frame with the extent of the stack perpendicular to said feed plate;
• a feed device capable of pushing a pair of sample blocks perpendicularly to a plane formed by the samples in the loader while said pair of sample blocks is carried by the feed plate from an initial position located in line with the loader, with simultaneous translational movement of the two sample blocks to a loaded position;
• two clamps one of which is fixed and cooperates with the force detector while the other cooperates with the movable element of the tensioning means, said sample blocks in their loaded position being received in said clamps, the said feed device being retractable to its initial position to engage a new pair of sample blocks carried by the feed plate;
• control means for triggering the operation of the tensioning means when the sample blocks are in position in the said clamps;
• one measuring means, associated with the force detector, providing the value of the tensile force applied to the sample;
• other measuring means, associated with the movable element of the tensioning means, providing the value of the elongation of the sample;
• and means for returning the tensioning means to an initial position after its movable element has been subjected to sufficient translational movement for the measurement, said feed device being operable, when bringing a new pair of sample blocks into the clamps, to cause the previous two sample blocks to be driven out from the said clamps.