drive 50 which is operated by handle 52 see fig3 as seen in fig3 the lever is in a substantially horizontal position parallel to the track 40 in which a roller 54 is received said roller being rotatably mounted to the free end of the lever arm 46 thus as handle 52 is rotated the lever arm 46 is also rotated about point 47 forcing the window to move upwardly as the roller traverses the track 40 as seen in fig4 it can therefore be seen that the window unit is capable of being adjusted for various opening modes however as an important feature of the present invention the window unit 14 is hingedly connected to the casement 16 by hinge means indicated generally at 60 this provides a complete separation of the window unit 14 from the fixed window casement 16 as seen in fig5 and 6 thereby permitting the vehicle to have an unobstructed opening to the ventilation of the interior of the vehicle accordingly the hinge means 60 comprises a first hinge member 62 affixed to flange 22 of the casement 16 by suitable means such as rivets 64 said hinge member 62 includes a pin 65 held in a fixed position to member 62 by hinge fingers 66 the second hinge member 67 of said hinge means 60 is affixed to an annular flange 68 of the window frame unit.