Patent GB-191229774-A (GB)
Title: Improvements in Electric Cable Connecting Boxes or Apparatus.
IPC: H02B1/00
Filed: 1912-12-27
Granted: 1913-12-29
Abstract: 29,774. British Insulated & Helsby Cables, Ltd., and Blades, R. W. Dec. 27. Boxes; switch mechanism interlocking with lids.-Relates to cable connexion boxes situated at the ends of main cables and provided with switches and fuses, and adapted to receive a detachable plug connector on the end of a trailing cable which is to be supplied from the main cable. The box is provided with separate compartments enclosing respectively the main cable terminals, the switch, and the fuses, and with interlocking mechanism between the switch and the cover of the fuse compartment and also between the switch and the removable plug, so that neither the fuse-cover nor the plug can be removed unless the switch is open, while both must be replaced before the switch can be closed again. In the box apparatus as illustrated in Figs. 1 and 2, for use with three-core cables, the main body of the box 1 consists of two compartments 16, 17 separated by a wall 6. The main cable 7 enters the right-hand compartment 16 through a gland 99, and the separate cores branch out to terminals 10 mounted on insulators 81. The terminal shanks pass through the insulators and are attached to switch contacts 13. The fuses 12 in the left-hand compartment 17 are seated in clips 82. The clips on the right-hand side are attached to shanks running through insulators 83 and terminating in switch contacts 14, and the clips on the left-hand side are attached to shanks running through the outer wall of the box and terminating in sockets adapted to receive the plug connectors of the trailing cable 9. The detachable coupling-member is hollow, and comprises a compartment 25 containing the cable terminals and preferably filled with an insulating-compound, a removable lid 31, and an open cup-shaped part 26 surrounding the plugs 30. The cup 26 fits into a larger conicalsided cup 27 attached to the box 1 so as to surround the outwardly projecting sockets. Springs 90 assist in guiding the detachable member into place. A separate cover attached by a chain may be fastened by bolts and nuts over the cup 27 when the plug is removed. The switch compartment consists of a deep dish 4, attached below the box 1, and a plate 5 shaped to give space for crank and lever mechanism by which the switch is operated from an outside handle 36. The stationary contacts 13, 14 are, as described above, carried on the ends of terminal shanks running through the insulators 81, 83. The movable contacts 15 are attached to a transverse bar 40 adapted to slide up and down guide-rods 41. For use with high-tension circuits, the switch contacts are immersed in oil or other insulating-liquid in a tank 85. Guide-lugs 86 and guide-rods 87 are provided to facilitate removal and replacement of the dish 4. A connecting-rod 49 and linkages 50, 51 operated by the switch mechanism are attached to catches 46, 55 which lock, respectively, the fuse cover 3 and the plug 30 in their places while the switch is closed, and unlock them when the switch is opened. Additional catches 60, 67 are actuated by springs upon the removal of the fuse cover and the plug, so as to engage the first-mentioned catches and thereby lock the switch in the open position, the lock being removed when both the cover and the plug are replaced. The cover 2 of the compartment enclosing the main cable terminals is locked on by a bolt 88 screwing through the wall 6 and accessible only through the opening of the fuse compartment when its cover has been removed. The box is earthed and is connected to the cable sheaths by a flexible conductor 97 attached at one end to a clamp 96 on the cable armouring 95, passing through a clamp 102 in connexion with the inner sheath 98, and attached at the other end to a socket 103 which is engaged by a pin 105 carried on the detachable coupling-member, the pin 105 being connected by a conductor 104 to the sheath of the cable 9. In a modification shown in Fig. 3, the box is adapted to receive two more detachable plug connectors 110, 118, which are attached respectively to the high-tension and low-tension leads of a transformer, so that the current for the main cable passes to the trailing cable via the transformer. The hightension connector fits into the fuse compartment and has pins 113 entering sockets formed at the ends of the terminal-shanks to which are attached the fuses 12. The low-tension connector fits into an additional compartment to the left of the fuse compartment, from which it is divided by a wall 125, and has pins 120 entering sockets 121 electrically united to the sockets 22 of the detachable connector for the cable 9. Both connectors are locked in their sockets by catches 126 when the switch is ' on,' and are unlocked by a rod 50 when the switch is opened. Additional catches 128, operating as previously described upon the removal of the connectors lock the switch open until the connectors have been replaced. The transformers may be mounted in the box, and a stand 131 supports the whole apparatus.