Window shade for curved or non-rectangular vehicle windows

A window shade (13) for motor vehicles which can be retracted and extended along an actuation path, comprising:

• a window shade web (14), which is bordered by two longitudinal edges (18, 19, 75, 76) extending generally in the direction of the actuation path and two transverse edges (17, 71, 74), one of which forms a free edge (17, 71) that moves along the actuation path in the course of retraction and extension,
• a drive (29, 47) for moving the window shade web (14) along said actuation path between extended and retracted positions;
• a stowing device (24, 25, 105, 106, 107) for stowing the retracted window shade web (14) when in said retracted position,
• said web being made of an elastic, stretchable and contractible material which as an incident to movement of the window shade web in one direction along said actuation path is stretched in a direction transverse to the longitudinal edges for increasing the transverse width of the web and as an incident to movement of the web in an opposite direction along an actuation path is contracted to reduce the transverse width of the web,
• at least two guide rails (43, 44, 72, 73) whose distance between each other changes along said actuation path for changing width of the window shade web (14) in response to movement of the web in the direction of said actuation path,
• said guide rails (43, 44, 72, 73) each defining an associated first groove (91) having a relatively narrow width groove slit (92) communicating with a relatively larger interior cavity (94) that defines a shoulder (95), and
• said window shade material (14) including pulling members (96) on its longitudinal edges (18, 19, 75, 76) which are guided in said first grooves (91) and are designed such that they extend behind the shoulder (95) in order to generate a pulling force transversely to said first grooves (91) on the window shade web material (14) in response to movement along said actuation path.