| 摘要 |
<p>945,434. Terminal boards. WILLEM SMIT & CO'S TRANSFORMATORENFABRIEK N.V. March 13, 1961 [March 19, 1960], No. 9131/61. Heading H2E. A switch is connected directly or indirectly between an earthing terminal and one of two secondary terminals of a welding transformer (not shown), the position of the switch depending on the shape of the cable-shoe connected to the said secondary terminal. With the conventional shaped cable-shoe 28, Fig. 4, connected to the secondary terminal 24, contact block 22 attached to the inner end of terminal 24 is drawn towards earthed strips 23 against springs 26, thus closing switch 22, 23, and earthing cable 19 from the transformer and cable 31 from the workpiece. With the tubular shaped cable shoe 33, Fig. 5, attached to terminal 24, the switch 22, 23 is held open and the earth connection of cables 19 and 32 remains interrupted. Fig. 8 shows a modification which . incorporates a double switch, contact block 37 being insulatedly attached to terminal 24 and block 22 so as to contact earth-contacts 34 when the switch 22, 23 is open and thereby earth one of the direct current terminals of a rectifying system (not shown) used when welding with direct current.</p> |
