| 摘要 |
<p>An arrangement for severing webs, particularly fabrics, of thermally severable materials includes a severing tool which is mounted on a support for displacement between an extended position and a retracted position thereof, being urged towards its extended position. The severing tool has a severing portion which is heated and which contacts and severs the web during the movement of the latter longitudinally of itself in a path past the support for the severing tool. A heat-conductive member is in heat-transmitting contact with the severing tool at the severing portion thereof in the extended position of the severing tool, the heat-transmitting relationship being interrupted when the resistance of the web to the severing action of the severing portion achieves such a value that the severing tool is displaced from its extended position toward its retracted position. The severing portion may be either a reduced cross-section portion of a U-shaped severing member mounted on the severing tool, or a replenishable section of a wire, either one of which is heated by an electric resistance accompanying the passage of electric current therethrough. The position of the abutment member relative to the severing portion of the severing tool may be adjustable, and so may the force with which the severing tool is urged toward its extended position. When the severing tool reaches its retracted position, either the entire arrangement may be shut off or the amount of electric current delivered to the severing portion may be stepped up.</p> |
