| 摘要 |
<p>A knee joint having first and second members (10, 30) pivoted together for fiexion and extendion has a spring loaded plunger (18) in the knee member (10) that latches into a socket (34) in the knee housing (30) to hold the knee in its extended position. A solenoid (40) operatively connected to the plunger (18) unlatches the plunger (18) from the socket (34) and a sensor (46, 47) detects unlatching movement of the solenoid (40). A circuit (44) responds to activation of operating switch (45) and to the sensor (46, 47) to reduce the current through solenoid (40) to a holding value when unlatching occurs within a set time after operation of switch (45) and in the absence of movement substantially de-energises the solenoid (40). The solenoid is reliable in operation and failure to release does not bring about undue power drain.</p> |
