DE84867C - - Google Patents

Description

IMPERIAL

PATENT OFFICE.

CLASS 52: Sewing machines.

The innovation relates to a special training of sewing machine grippers and is especially intended for the case that the hook with a needle that Crank pin is operated, cooperates and is to be prevented that the Upper thread is pulled down as a loop, while the needle through, the Arbeitsstüc'k goes up. If the upper thread were already pulled down as a loop while if the needle is still in the tough fabric, the thread would be in the needle hole of the The fabric must be pulled along next to the needle that is still there and tear easily, because it is wedged in the needle hole by the needle. Only when the needle has left the needle hole does the needle thread come loose, without finding any disadvantageous resistance in the needle hole, as a loop around the spool of thread to lead.

Care is also taken that not only the upper thread loop through the gripper is held securely during its operation until it is sufficiently short is no longer twisted or tangled when the upper thread is pulled up by the thread lifter but also that the bobbin thread is kept out of the path of the hook point and the needle, although the same is moved up and down close to the hook tip, is protected against breaking.

Gemäfs the accompanying drawings of the loop-taker hook of the gripper of a long shaft is formed α, which is thickest in its middle part and drawn, after his neck parts ^α Λ tapered shape. As a result of this tapering, the purpose mentioned at the beginning is achieved, that no thread is pulled down by the upper thread loop formed while the needle goes up through a thick work piece. Only when the needle has emerged from the workpiece (Fig. 2) does the loop widening begin.

The gripper has a wide tail piece at its rear end a ? on, which extends to under the loop catcher hook α . Between these two parts there is an opening or a slot a ^s into which the upper thread loop enters and from which it is pulled out again by the thread lifter after it has passed over the bobbin case and has wrapped around the lower thread. The tail piece a ² prevents the premature slipping of the upper thread loop, which in certain positions of the hook, for. B. in that of Fig. 3, may be caused by some impropriety. Then, however, the tail ^{piece (2)} lies in front of the noose and does not allow it to slip over the gripper under any circumstances.

The tail piece is made so wide that its front surface a ⁴ protrudes slightly towards the front side of the looper hook, whereby the bobbin thread is held laterally out of the way of the looper hook when the latter advances to grasp a loop of the upper thread. This relationship can be seen in Fig. 5, according to which the loop catcher hook α against the tail

piece ά ² jumps back to the right to something, so that a bobbin thread drawn over the front surface α ⁴ · of the tail piece cannot be caught by the hook α.

Behind the slot α ⁵ is the part a ^{6 of} the hook, the front side of which in the direction of the forward movement serves as a stop for the upper thread loop into which the loop catcher hook has entered (Fig. 2), in such a way that, while the hook moves to the position of Fig. 3, the loop enlarged and passed down around the bobbin case to be pulled up on the rear side of the bobbin case.

The wide tail piece a ² is provided with an elongated needle hole a ~ ' (Fig. 5), to the side of which an attachment a ^{8 is} in line or at least close in line with the loop catcher tip. This approach a ^& protects the needle from breaking off by moving in front of the snare hook when it catches a loop.

The tail ^{piece a 2 also} has a lateral attachment or hook a ⁹ (Fig. 5), which, when the hook is in its rearmost position, pulls enough thread length from the bobbin for the next stitch by pulling the hook a ⁹ engages behind the bobbin thread running over the front surface a ^{4 of} the tail piece a ^2.

Fig. Ι shows the position of the descending needle to the approach a ⁸ , while Fig. 2 shows the position of the looper and the needle when the loop catcher hook has entered the loop of the upper thread and the eye of the needle is above the work piece. The gripper then moves from the position of FIG. 2 to the position of FIG. 3 in order to bring the loop around the bobbin case. Fig. 3 shows the gripper in its foremost position. In the position of Fig. 4 the gripper has been moved back so far and the loop shortened so far that it can no longer be entangled:

The above-described gripper parts, ie the ^{loop catcher part consisting of the shaft a and the slot a 5} and the tail piece a ¹ with its needle hole a ⁷ and needle locking attachment α ⁸ and the protruding surface λ ⁴ and the hook a ⁹ are closely related to each other, there According to the above explanations, the long-shafted loop catcher part needs the tail piece a ² not only to form the entry ^{opening a 3} for the upper thread loop, but also the tail piece to carry a protruding surface a ^{4 that} keeps the bobbin thread away from the loop catcher part a ^{and a needle hole a 1} and - an approach a ⁸ is used, which is available to protect the needle against the loop catcher part. The tail piece a ² with its mentioned details is therefore an indispensable means of being able to use the long-shafted snare part a.

Claims (1)

Patent claim: Gripper for lockstitch sewing machines, which delays the widening of the upper thread loop until the needle emerges from the work piece by means of a tapered rear part of a long-shaft loop catcher hook (a) that glides under the loop and does not pull down a thread and to protect the bobbin thread and the needle against this hook one with the latter one entry opening for each Upper thread loop has a tail piece (a ² ) which forms and prevents the loop from slipping prematurely , which carries the bobbin thread through a front surface (cfi) protruding towards the front side of the loop catcher hook and the needle through a guide attachment (cf) to the side of its elongated needle hole (a ¹⁾ out of the area of the hook. 1 sheet of drawings.