US 4,062,309 AGranted

Automatic feed device for sewing machine

AssigneeDurkoppwerke GmbH

InventorsKonrad Pollmeier, Franz Hannemann

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Abstract

A pair of tracks are pivotal and alignable with a stitching station of a sewing machine. Carried on each track is a clip which is normally biased away from the sewing machine but displaceable against the biasing force toward the stitching station. Each clip has a lower jaw swingable between an upper operative position and a lower return position and an upper jaw pivoted on the lower jaw and swingable between an upper open position, a lower operative position, and a third return position. In the return positions both of the jaws are below the plane of the support table adjacent the sewing machine. The trailing edge of a workpiece is clipped in one clip and the leading edge of the workpiece is fitted to the sewing station. As the clip approaches the sewing station it first automatically opens, then is automatically swung into the return position so that a workpiece whose trailing edge is held in the other clip can then pass over the returning clip to the sewing station.

In combination with a sewing machine having means for advancing a workpiece to be stitched in a transport direction through a sewing station:

a pair of elongated tracks extending next to and spaced from each other parallel to said direction;
means for displacing said tracks transversely to said direction between a pair of end positions;
a clip displaceable along each of said tracks and having means defining a mouth open toward said station for gripping the trailing edge of a workpiece being advanced through said station;
means for urging each of said clips in a direction away from said station to hold workpieces engaged by said clips taut, said tracks having downstream ends adjacent said station and upstream ends remote from said station;
and
an element connecting said tracks rigidly together at said upstream ends and provided with a pivot transverse to said direction, said means for displacing including an actuator engaging said downstream ends for swinging said tracks about said pivot, said tracks lying generally below a support plane, each of said clips comprising:
a support displaceable along the respective track,
a lower jaw pivoted on said support and having an upper face and displaceable between an operative position with said face generally parallel to and on said plane and a return position with said jaw below said plane,
an upper jaw pivoted on said support and having a lower face and displaceable between an open operative position with said upper jaw above said plane and said lower face spaced above said upper face, a closed operative position with said upper jaw above said plane and said lower face juxtaposed with and clamping a workpiece with said upper face, and a return position with said upper jaw below said plane,
means for displacing said upper jaw from said closed operative position into said open operative position on approaching a predetermined position adjacent said station for releasing said workpiece, and
means for displacing said upper and lower jaws into said return position on displacement of said support back away from said station.

8 more elements

Abstract

Claims8