2.558 I. Nasch, for improvements in the construction of sewing machines for over-sewing, embroidering, eye letting and button holing.
February 22, 1886
This invention consists, first, in an improved mechanism for giving a lateral, or to and fro, motion to the needle bar, and to the looper or other interlocking thread mechanism and secondly, to an improved thread controller for sewing machines.
It is well known that in this class of sewing machines, the loop passing through the material and those passing over the edge have to be tied together to cover the edge, and to form the loops into stitches. For this purpose loopers of various kinds have been used in single thread machine, to bring the one loop interlock with the other below the material, and shuttles or other loopers in lock-stitch machines to lay a locking thread in the successively formed loops of the needle thread. This invention refers to shifting laterally the acting position of the underlooping or interlocking thread mechanism, whether it be of the looper class or circular, oscillating shuttles or other locking thread mechanism, so that the acting positions of such mechanism shall correspond to the positions that the needle takes in passing alternately through the work and over the edge of the fabric and it will be easily understood that the application of the principle embodied in this invention is equally applicable to either of the above classes of loopers or shuttles, whether of single or double thread machines. The action of the machine is as follows : the needle descends, say through the left hand-side of the needle hole, passing through the material on the throat or work-plate and throws out its loop in the ordinary manner. The looper, which at this time is held by a cam in its most advanced lateral position, enters the loop of the needle thread, opening it out, the looper is now withdrawn laterally to the right-hand position by the action of the spring and there held, the concentric part of the cam serving as a stop. The needle having been withdrawn from the work, its swinging head is rocked over to its right-hand position by the action of the spring, and the feed of the work takes place (mechanism of well-known or ordinary description being employed for this purpose). The needle again descends, this time through the right-hand side of the needle hole, and presents another loop to the looper now in a lateral position. The looper, still holding the first loop of the needle thread, enters this second needle loop and carries it through the previous one. As the needle again rises out of the work the looper releases the first loop in the usual manner, and the thread controller, operated by the cam. will now clamp the thread as before mentioned, namely, between the finger and the plate of the swing head, thus stopping the supply of thread from the spool, whereby the rise of the needle will draw up the slack of the released loop and tighten the stitch. The descent of the loop controller bar to clamp the thread will cause the end of the controller bar to press upon the inclined recess on the needle head ; and as the needle is rising to its highest position the head will be rocked to its first position, that is, immediately over the left hand side of the needle hole. A succession of the above movements produces the overhead stitch employed for edge binding or ornamentation. The above described mechanism for rocking the needle head so that the reciprocations of the needle shall take place on two vertical planes alternately, and for bringing the looper mechanism into position to act upon the needle loop at both these vertical planes, is equally applicable whether the shaft carries a looper of the class shown or any of the well known circular shuttles or locking thread-laying mechanism.