Device for sewing together plies of material adjusted to equal lengths

摘要

The device is for use in a sewing unit including a sewing machine and includes a vertically oriented relatively elongated intermediate plate separating two plies of material in advance of the sewing machine. Guide elements adjacent the intermediate plate support a clasping station for movement longitudinally of the intermediate plate. The clasping station includes a support mounting two clasps each selectively engageable with a respective ply of material. Photoelectric sensing devices are movable with the clasping station, and include respective sensing devices operatively associated with each ply of material and each operable to control engagement of a respective clasp with the associated ply of material responsive to sensing of the trailing edge of the associated ply of material. A counterweight arrangement exerts an adjustable pull on the clasping station in a direction opposite to the feed direction of the plies of material. In one embodiment, a lifting carriage supports the sensing devices and effects lifting of the clasping station. In a second embodiment, the sensing devices are mounted on the same support which mounts the clasps.