1. Field of the Invention
The present invention relates to a window blind for use between double panes of glass.
2. Description of the Prior Art
It is well known in the art that double panes of glass in a window provides better insulation than a single pane of glass. It is also known in the art to provide venetian type blinds or pleated shades between two panes of glass. A pleated blind between window panes is disclosed in the U.S. Pat. No. 4,913,213 to Schnelker. A venetian or slat blind between panes of glass is disclosed in the U.S. Pat. No. 4,687,040 and 4,664,169. Control means for lifting, lowering and tilting the blind from one side of the window must be provided while maintaining the window seal.
The U.S. Pat. No. 4,664,169 to Osaka et al. discloses a device for tilting slats of a venetial blind between double panes of glass. The device uses electrical power driving means to move piezoelectric bimorph device in a horizontal plane. The piezoelectric bimorph device is mounted to a block having a threaded bore. The block is secured to a screw which is threaded to a nut after passing through one pane of glass. The piezoelectric bimorph device mechanically moves an elongated V-shaped beam under two cross arms which control the rotation of the slats. When the beam is moved, the cross arms are tilted, thereby rotating the slats.
The U.S. Pat. No. 4,687,040 to Ball discloses a device for adjusting the tilt angle of slats of a slat blind positioned between the panes of glass. The device includes a hole in one pane of glass and a flexible cable passing through the hole. The cable is connected to a rectangular member which controls the rotation of the slats. When the cable is turned by external torque, the slats are tilted.
The U.S. Pat. No. 4,913,213 discloses a pleated blind between double window panes and blind control means for raising and lowering the blind. One embodiment is comprised of an aperture in one pane of glass and a bolt with a center hole mounted in the aperture. An actuator cord passes through the bolt hole and further up and over a screen, if desired, thereby providing an external control mechanism. Another embodiment provides routing the actuator cord over the glass housing and any screen housing provided. One of the problems with this blind is that sharp edges of the bolt cuts the actuator cord thereby shortening the life of the blind.
All of these control systems either have complicated mechanisms or require a headrail which is too wide to fit between the panes of those windows whose panes are not more than 3/4 inches apart. Thus, the prior art blinds are either not suitable for currently popular double or triple windows, or difficult to make, install and maintain.