| 摘要 |
The contact making device includes the tapered helical spring (1) that is manufactured of stainless steel with several turns of decreasing diameter, pressed on to an aluminium support (2) and secured with two steel pins or screws (3) at its ends. A nut (5) enables the device to be fixed to an extension of the earthing pole. A hole (7) of diameter 4 mm in the support accepts a plug at the end of a test lead (8). The end (6) of the spring is straight, to facilitate hooking.
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