| 摘要 |
The invention provides a device for facilitating the repositioning of a rail having a rail base and which is moveable between first and second positions. The device includes rollers pressed against an underside of the rail base by the action of spring means when the rail is located between the first and second positions. The rollers are articulated to pivot, whereby, when the rail base is in one of those first and second positions, the rollers are pressed by the force of the spring so as to move in a direction above the underside of the rail base by a distance which is at least one-third the height of the rail base, and thus engage an edge of the rail base. The rollers can comprise separate rollers, each of which is forced against a respective opposite edge of the rail base by the spring means when the base is in the first and second positions, and the rollers preferably are articulated to pivot about a common pivot axis.
|
