Patent GB-601741-A (GB)
Title: Improvements in or relating to apparatus for testing the strength of filamentary materials
IPC: G01N3/14
Filed: 1945-10-10
Abstract: 601,741. Testing physical qualities of filamentary materials. BRITISH CELANESE, Ltd. Oct. 10, 1945, No. 26473. Convention date, Oct. 10, 1944. [Class 106 (ii)] Apparatus for testing tenacity and extensibility of yarns and filaments under a substantially constantly increasing load comprises a tubular support 9, an arm 14 pivotally mounted on a knife edge 12 on the support and carrying a filament holder 19, means, such as a chain 98 attached at one end to the arm 14, for applying a constant rate of loading to the arm, a second filament holder 45 slidable by manual operation on the support to take up the increase in length of a specimen under load, and means operating automatically to prevent further increase in load on breakage of the specimen. The support 9 and a further tubular support 11 are carried by a base 8 having levelling-screws 104. One end of the arm 14 is shaped as a pointer moving over a fixed scale 17, and the other end is screwed to carry balance weights 21. Means comprising an eccentric pin, operated by a knob 25, engaging a bearing member within the support 9 enables the arm 14 to be lifted from its pivot to rest in slots in a bearing member 26. The second holder 45 has screw-threaded engagement with a screw 43 on a slide carrying a scale and movable vertically in a slot in the support 9 on the operation of a handle 35 which turns a screw 33 engaging a bracket of the slide within the support 9. The screw 43 is operated by gearing 44, 51, a rod 49, gearing 52, 53 and a manually-operated knob 55 (not shown) which is situated above the base 8. The other end of the chain 98 is secured to a plate 99 carried by a block 57 (not shown) slidable within the support 11 and operated by a chain 105 passing over a pulley 106. Downward movement of the plate 99 and block 57 is controlled by a dashpot arrangement comprising a tube 56 secured to the block and extending down the support 11 into oil. A piston secured near the end of the tube 56 prevents oil passing the space around the tube on descent thereof, but will allow oil to be byepassed on the ascent of the piston and tube. A screwed rod 59 within the tube 56 carries a valve adapted to control the opening in the bottom end of the tube, oil passing up the tube and out of openings therein above the piston and into the space in the support above the piston on descent of the tube. A scale 107 on the tube 56 co-operates with a vernier 108 secured to the support 11. The tube 56 is clamped by brake bands 67 which can be opened to release the tube on the upward movement of a rod 72 on depression of a knob 79. The brake is applied automatically on the breaking of a filament by tripping-means operated from the arm 14. This tripping-means comprises an arm 95 (not shown), engaging over the arm 14 near the balance weights 21, provided with a latch engaging a ledged portion on a vertical rod 91 slidable within a tube 87, the lower end of the rod engaging a bell-crank lever connected by a rod to a trip lever 81 (not shown) which retains the brake release rod 72 in the raised position. When the rod 91 is released, the lever 81 is .tripped. In operation, the chain 105 is pulled downwardly to adjust plate 99 carrying the chain 98 to the upper and zero position, the brake 67 is applied, the holder 45 adjusted by means of the knob 55 (not shown), and the arm 14 balanced by moving the weights 21. The arm 14 is then lifted from its pivot to rest in the slots in the bearing member 26, the test filament clamped in the holders and the arm 14 lowered to rest on its pivot and adjusted to zero by rotating handle 35. The load is applied by depressing knob 79 to release the brake, whereupon the chain 98 moves downwardly, and the arm 14 is maintained in its initial position by gradual rotation of knob 55 (not shown) to raise holder 45. On breaking the specimen, the total elongation is read from the scale over which the holder 45 moves, and the load can be read from the scale 107 and vernier 108. A background board 112 is secured to the support 9.