Patent ID: 6601519
Filing Date: 2003-08-05
Classification: B60L,B65G

Abstract:
An apparatus (10) for supporting and stretching a film web in a tenter fame, the apparatus (10), arranged in reference to a Cartesian coordinate system, for transporting a carriage (40) along a track (20) in a non-contacting, substantially magnetically drag-free manner, comprising:a track (20) having an axis (20A) oriented along a first x-axis direction, and having one or more magnets (24) mounted on the track (20), each track magnet (24) being displaced from the first x-axis direction in a second z-axis direction and having its magnetization vector (24M) oriented in the yz-plane at a predetermined angular direction relative to the z-axis; a carriage (40), guided by the track (20), and having one or more magnets (42) mounted on the carriage (40), each carriage magnet (42) having its magnetization vector (42M) oriented in the yz-plane at a predetermined angular direction relative to the second z-axis direction to interact with the one or more track magnets (24), said interaction being magnetically stable in a third y-axis direction and magnetically unstable in the second z-axis direction, the carriage (40) having mounted thereon a clip assembly (150) adapted to grip the film being supported and apply a film-stretching load along the third y-axis direction; and a passive stabilization means (70) for stabilizing the position of the carriage (40) in the magnetically unstable second z-axis direction by substantially constraining carriage motion to the xy-plane without inducing mechanical friction or magnetic drag on the carriage (40), so that the carriage (40) may be transported in a stable path along the track (20) without mechanical contact while supporting the applied film-stretching load along the third y-axis direction, the path of the carriage (40) being displaced from the first x-axis direction in the third y-axis direction at a distance corresponding to the magnitude of the applied load.