GB1352327A - Tensile member with tension indicator - Google Patents

Abstract

1352327 Tension indicators J V H TRIGG 12 Aug 1971 [19 Aug 1970] 39995/70 Heading F2H [Also in Division G1] To enable the tension of a tensile member 1 to be checked, a pin 3 is movable within an axial bore 2 of the member 1 towards a stop, to urge a bi-stable resilient member 4, e.g. a Belleville spring secured to the pin 3, against a surface 6 of the member 1 remote from the stop. When the member 1 sustains a predetermined tension, it is elongated sufficiently for movement of the pin 3 to the stop to cause the resilient member 4 to snap over from one stable configuration to the other with an audible click. The test pressure to move the pin 3 is applied manually, either directly or via a tool 13. A return spring 8 acts on the pin 3 to restore the resilient member 4 to its first stable configuration when the test pressure is removed. A flexible metal or platics push-button 9 is secured to the outer end of the pin 3 and is force-fitted into a counterbore in the end of the member 1. It has an internal shoulder against which the rim of the resilient member 4 bears during the return movement of the pin 3. As shown, the stop is the bottom of the bore 2. In Fig. 1, the tip of the pin 3 is initially a tubular portion (12) (Fig. 2, not shown) heat-treated to be plastically deformable. With the member 1 loaded to the predetermined tension, a pressure greater than can be applied manually is applied gradually to the pin 3 to deform its tip (12) until the spring 4 just snaps through, the pressure then being relaxed. In Fig. 3, the pin 3 is tubular and has a resilient scroll-section tube 22 pressed into its tip, the required setting pressure being greater than can be applied manually. The calibration procedure is similar to that for the previous embodiment, except that the effect of the gradually applied pressure on the pin 3 forces the tube 22 further into the pin 3. In a modification, a solid-tipped pin 3 co-operates with a volute spring lodged in the bore 2 to form a stop, the calibration procedure determining the position of the volute spring in the bore. In a further modification, a second pin in the bottom of the bore 2 has its point facing the tip of the pin 3 to be jammed in a hole therein, the calibrating pressure acting to force the point of the second pin into the hole in the pin 3.