| 摘要 |
<p>The passive jaws (7, 8) of a power tong (1) are mounted on jaw holders (10) which are slidable in recesses (11) in a rotary (3). The jaw holders (10) have an internally threaded bore (12) which engages a threaded shaft (13) which has a shoulder (14). An actuator (16) is mounted on the housing (2) of the power tong (1) and can advance a drive shaft (17) into a socket in a drive spindle (15) of the threaded shaft (13). Rotation of the threaded shaft (13) in one sense advances the jaws (7, 8) toward the centre of the power tong (1) whilst rotation in the opposite sense withdraws the jaws (7, 8). The drive shaft (17) is withdrawn to enable the rotary (3) to rotate. A jaw holder (10') with a resiliently mounted self-aligning jaw (7') is also disclosed.</p> |
