Patent GB-663899-A (GB)
Title: Improvements in or relating to tension meters
IPC: G01N3/08
Filed: 1949-06-03
Abstract: 663,899. Measuring forces; indicating- apparatus. SAXL, E. J. June 3, 1949, No. 14938/49. Classes 106 (ii) and 106 (iv). Apparatus for measuring the tension of yarns, wires or the like comprises a base or casing, a resiliently biassed element adapted to contact the yarn or the like movably mounted thereon or therein, a pair of abutments for engaging the yarn or the like spaced apart and mounted on a carrier itself mounted on or in the base or casing and a stop for limiting displacement of the carrier in the opposite direction to that in which the contact element is biassed. Thus, by displacing the carrier away from its stop, the yarn or the like may be readily engaged with the abutments and contact-element. The casing of the device is formed with a handgrip 30 and, in use, an extension 31 of a lever 16 is first pulled by the fore-finger to rock the lever against the action of a spring 27 which normally holds it against an adjustable stop 34. The lever 16 projects through a slot in the casing and is integral with a guide-plate 20 carrying a pair of abutment rollers 21, 22 which are thus lowered to enable them to be placed below the yarn or the like which itself is arranged to pass below a third contact roller 24. When the lever 16 is released, the tension in the thread urges the roller 24, which is carried by a balanced lever 35 moving in a slot in the guide-plate 20, upwardly. Counter-clockwise movement of the lever 35 is resisted by a flat spring 47, secured to a stud 50 and connected with the lever by a hooked strap 53 or by a strap having opposed knife-edges. The end of the lever 35 is toothed and engages a pinion on the shaft of an indicating pointer 15 which may carry a flywheel to reduce vibration. Stops 45, 46 limit the movement of the lever 35 and a pin 57 is adjustable to vary the effect of the spring. The slot in which the extension 31 of the lever 16 moves is normally closed by a further extension 32. The rollers have surfaces of V-shaped section and project into circular recesses in the plate 20. Each carries internally a bearing liner which engages between shoulders on a bearing screwed into the plate 20. In other embodiments, the lever 35 is loaded by a coilspring and in one arrangement, a spiral spring has one end fast to the pointer spindle to load the lever 35 indirectly and take up back-lash. In a further modification, the lever 35 is loaded by a flat spring and actuates the indicating pointer through a magnifying train of gears which are independently loaded by a spiral spring to take up backlash therein. Pointers, concentric with the indicating pointer, may be provided to be hand set to show the desirable upper and lower limits of the tension being measured. These, or alternatively the stops for the lever 35, may be insulated and co-operate with the indicating pointer electrically to control appropriate mechanism should the limits be exceeded. In order positively to lock the guide-plate normally in its upper position, the lever 164, Fig. 16, carrying it may have a cam surface 176 to co-operate with a projection 174 of a separate trigger 173. A spring 168 connects the lever to the trigger which itself is loaded by a spring 177. The parts are of metal or plastic construction.