| 摘要 |
PCT No. PCT/US93/11368 Sec. 371 Date Jul. 15, 1996 Sec. 102(e) Date Jul. 15, 1996 PCT Filed Nov. 22, 1993 PCT Pub. No. WO95/14843 PCT Pub. Date Jun. 1, 1995A shape memory alloy actuator is disclosed. In one arrangement, a louvered window covering, such as a vertical or horizontal venetian blind, is provided with a thermal actuator to automatically rotate slats forming the louvered window covering between open and closed positions. The actuator includes at least one shape memory alloy spring that, when heated above a predetermined temperature, extends to engage and move a rack that drives a pinion gear. The pinion gear rotates, through a coupling mechanism, a rod extending the length of the blind. A second shape memory alloy spring may be installed to rotate the rod in the opposite direction. The rod intercouples the slats in a manner such that the rotation of the rod rotates the slats in unison between closed and open positions. The shape memory alloy spring may be heated with a current supplied by a controller in response to a predetermined environmental condition. The venetian blind mechanism's manual actuation would not be compromised or interfered with by the thermal actuator of the use of the thermal actuator because the thermal actuator is not physically coupled to the blind except intermittently. |
