Patent GB-955433-A (GB)
Title: Improvements in or relating to devices for locating equipment on overhead lines
IPC: H02G1/02
Filed: 1961-08-21
Abstract: 955,433. Trolleys for locating equipment on overhead lines. CENTRAL ELECTRICITY GENERATING BOARD, and D. W. VAUGHAN. July 31, 1962 [Aug. 21, 1961], No. 30079/61. Heading B7L. A device for locating equipment on an overhead line such as an overhead electric conductor comprises a frame to which equipment, e.g. for testing the cross-section of a conductor 9, Figs. 1 to 4, by the use of a potentiometer 23, can be secured, the frame having a main frame member 1 and an auxiliary frame member 2 pivoted thereto by a pin 3 against the action of a biasing element, e.g. a spring 4, line engaging elements on the frame members e.g. rollers 5, 8, 8, on the member 1 and rollers 7, 6, 6 on the member 2, to engage the line and locate the members relative thereto for movement therealong, and latching mechanism 10 to 12 carried by the members 1, 2 and operable sequentially by a towing element 18 to retain the elements 5 to 8 in a first position thereof in which they are spaced apart to facilitate the initial mounting of the device on the line, to retain the elements in a second position thereof in which they are engaged with the line under the influence of the biasing element 12, and to retain the elements in a third position thereof in which they are again spaced apart to permit removal of the device from the line. The latching mechanism comprises a plate 10 on the member 1 having a continuous slot 11 with concentric portions 11a, 11b, 11c and 11d selectively engageable by a pin 12 carried by an arm on the member 2 against the urge of an auxiliary spring 12a. Before the device is mounted on the line the members are spaced apart with the pin 12 in the slot portion 11a. When the device is located on the line as described hereinafter, rotation of the member 1 is at anticlockwise direction, Fig. 1, will cause the spring 12a to move the pin 12 into the slot portion 11b and thereafter to move under the urge of both springs 4 and 12a into the slot portion 11c with all of the rollers 5 to 8 then engaging the line. The device can then be towed by the element 18 which is connected by a ring 19 to a rod 20 on the member 1, the rod having a contoured portion 21 to receive the ring 19 at this time. By shifting the ring to the left in Fig. 1 against an abutment 22 and pulling the element 18, the member 1 is again rotated anticlockwise until the spring 12a engages the pin 12 in the slot portion 11d whereafter the device can be removed from the line. As shown in Figs. 3 and 4 the member 1, 2 respectively carry locating elements 13, 14 to position the device on the line prior to moving the members 1, 2 to the position shown in Fig. 1. Pivoted to the element 13 at 16 is a link 15 connected to a cord 17. When the members are spaced apart with the pin 12 in the slot portion 11a the cord 17 is thrown up over the line 9 and the device then hauled up until portions 13a, 14a on the elements 13, 14 guide the device on to the conductor, whereafter the members 1, 2 are operated as previously described. With the members 1, 2 in positions in readiness for removal from the line, a flick of the cord 17 dislodges the device from the conductor and the device is then lowered by the cord. For the purposes, e.g. of treating the cross-section of the conductor 9 for the presence of corrosion, the potentiometer 23 on the member 2 has a pinion 24 engaging teeth 25 on the plate 10, the potentiometer being connected by a cable 26 to an indicator the cable constituting the element 18. Clearly as the rollers engage on enlargement on the conductor the potentiometer will be operated. Contacts 30, 31 on the frame members are connected via another lead 32 so that when the rollers engage a bulge on the conductor an audible signal is given so that the operator can then cause the roller 7 to be moved again over the bulge while watching the indicator.