Sunshade device for motor-vehicles, with shape memory actuator

Abstract

A sunshade device comprises a sunshade in the form of a roller blind forming part of a roller-blind device, comprising a supporting structure, a shaft for rolling of the sunshade blind, mounted so that it can rotate on the aforesaid supporting structure, and a shape-memory actuator device for causing displacement of the blind from the rolled-up condition to the distended condition.

1 . A sunshade device for motor vehicles, comprising a sunshade that can be displaced between an inoperative position and an operative position with respect to a supporting structure, and a shape-memory actuator for controlling displacement of the sunshade from its inoperative position to its operative position, said device being characterized in that said sunshade is constituted by a blind of a roller-blind device, comprising a supporting structure and a shaft for rolling-up of the blind, mounted so that it can rotate in the supporting structure. 
     
     
         2 . The sunshade device according to  claim 1 , wherein the shape-memory actuator is provided for controlling movement of the sunshade only from its inoperative position to its operative position, said device further comprising: engagement means for withholding the sunshade in its operative position once this has been reached so as to enable de-activation of the shape-memory actuator element; means for de-activation of the aforesaid engagement means; and elastic means that bring back the sunshade into its inoperative position. 
     
     
         3 . The sunshade device according to  claim 1 , wherein a first shape-memory actuator element and a second shape-memory actuator element are provided for controlling movement of the sunshade into its operative position and into its inoperative position, respectively. 
     
     
         4 . The sunshade device according to  claim 1 , wherein the shape-memory actuator is of a bistable type, designed to cause at each successive activation a movement of the sunshade from the inoperative position to the operative position, or vice versa. 
     
     
         5 . The sunshade device according to  claim 1 , wherein the shape-memory actuator comprises: a shape-memory element wound around a rotatable disk, having one end connected to said rotatable disk and the opposite end connected to a fixed structure; means for electrical supply of said shape-memory element, designed to cause a heating of said shape-memory element beyond the transition temperature so as to bring about shortening thereof, with a consequent rotation of the aforesaid disk-like body on which the shape-memory element is wound; and a gear transmission for transmitting rotation of the aforesaid disk of the shape-memory actuator element to the shaft for rolling-up of the blind. 
     
     
         6 . The sunshade device according to  claim 1 , wherein said shape-memory actuator comprises a pair of shape-memory wires that can be activated for controlling rotation of two oscillating arms, each having one end supported in a rotatable way by the supporting structure of the roller-blind device and the opposite end connected in an articulated way to a slider that can slide along a cross member fixed to the free edge of the blind, in such a way that said oscillating arms are displaceable between an aligned retracted condition, corresponding to the rolled-up condition of the blind, and a condition where they are rotated outwards, in which they cause unrolling of the blind. 
     
     
         7 . The sunshade device according to  claim 1 , wherein said blind is made of fabric or of flexible plastic material and has two longitudinal edges englobing two metal wires or strips sufficiently flexible to enable rolling-up within the casing of the roller-blind device in the rolled-up condition of the blind, but sufficiently rigid to bestow upon the blind a rigid and self-bearing condition, in the distended condition of the blind. 
     
     
         8 . The sunshade device according to  claim 1 , wherein the supporting structure of the roller blind is connected to a bracket to be recured the structure of the motor vehicle via a ball-and-socket joint. 
     
     
         9 . The sunshade device according to  claim 8 , wherein the aforesaid articulated joint is provided in such a way as to maintain the casing of the roller-blind device clamped in any selected orientation and is in particular shaped in such a way as to enable an adjustment of the inclination of the plane of the blind in the distended condition. 
     
     
         10 . The sunshade device according to  claim 1 , wherein it comprises means for activation of the shape-memory actuator, comprising a control pushbutton, an electronic control unit, which activates a circulation of electric current through the shape-memory actuator following upon operation of the control pushbutton.