| 摘要 |
A straight-edge (1) is fitted with a weight (3) having an electrically conducting contactor (4). The contactor has a contact (5) on at least one side, fixed to the straight-edge (1) so that it is a set distance from the contactor (4) in the vertical position, with an electric control circuit. - Pref. several parts (5) are located around the contact (4). Switch (2), support (6), rod (7), locator sphere (8), support plate (9), screw (10) and cable feedthrough (11) complete the installation. |
