US2329691A - Lockstitch sewing machine - Google Patents

Description

Sept. 21,. 1943. F. ASHWORTH LOCKSTITCH SEWING MACHINE Filed Feb. 4, 19 12 Patented Sept. 21, 1943 UNITED STATE 2,329,691 .LOCKSTITCH SEWING MACHINE Fred Ashworth,

United Shoe Machinery Corporation,

Wenham, Mass, .assignor to Flemington, N. J a corporation of New Jersey Application February 4, 1942, Serial No. 429,477

Claims. (011112-48) The present invention relates to lockstitch sewing machines and more particularly to needle guides for such machines, the stitch forming devices of which comprise a curved hook needle, a rotary loop taker which acts to cast loops of needle thread over a locking thread case without itself passing bodily through the loops and in so doing, imparts a twist of 180 to each needle loop while passing over the thread case. The present invention represents an improvement in machines disclosed in U. S. Letters Patent to Hopkins No. 2,197,801 of April 23, 1940, afeature of which patent embodies an improvement in a well-known type of machine disclosed in the patent to Ashworth No. 1,169,909 of February 1, 1916.

The rotary loop takerin the machine of the patent to Ashworth above referred to is equipped with a hook having a loop entering beak for carrying each needle loop over the thread case, one leg of the loop engaging the inside of the beak between the loop taker and the thread case, and the other leg engaging the outside of the beak,

which legs are, for convenience of reference in the Hopkins patent, termed the inner and outer legs, respectively. To enable the outer leg of the needle loop to be carried across from one side of the plane of the needle to the other without becoming stranded thereon, the needle guide in the Hopkins patent is provided with a guard extending parallel to the needle to a position slightly beyond the needle barb. Such a guard deflects the outer leg of the needle loop away from the needle, while at the same'time leaving the barb free so that the inner leg of the needle loop may readily be removed from the needle. While the needle guide provided with the guard is effective for the purpose intended during removal of the loop from the needle, there frequently is a tend-* ency for each loop, after being carried about and freed from the locking thread case with its 180 twist, to become entangled with the needle or needle guide. To prevent entanglement of each needle loop with the needle or needle guide, after the loop is freed from the loop taker, the machine of the Ashworth patent is provided with a finger i secured to the frame of the machine projecting into close proximity to the needle guide when the needle and guide are in positions where the needle loop is freed from the thread case. The use of this finger requires special adjustments in the machine and a more careful regulation of the movements of the needle and guide than are required without the use of the finger;

The objects of the present invent'on are to avoid the use of a loop guiding finger projecting into proximity with the path of the needle guide in a lockstitch machine of the type referred to and to provide a needle guide with the use of which there will be no opportunity for the needle loop to be caught on the needle or guide after being freed from the loop taker, regardless of' whether a=guard on the needle guide isemployed or not. a 1

With this object in view, a feature of the invention contemplates the provision of a needle guide having an extension projecting towards the loop taker to a'point at a greater distance:

from the work than the length of the needle loop while being freed by the loop taker from the thread case so that there will be no opportunity forthe loop to become caught on the needle or guide. In the illustrated form of the'machine, each needle loop is presented to the loop taker by a loop spreader moving between the needle and the loop taker and as applied to this machine, the extension on the needle guide projects between the loop taker and spreader, thus effectively shielding the end of the extension from: the freed loop. Preferably the needle guide-is constructed with surfaces at both sides of the needle for deflecting the outer leg of each needle loop away from the hook of the needle both'while the loop is being transferred from the needle to the loop'taker and when freed from the looptaker, thus guarding the needle at the only times in each sewing cycle when danger of stranding or uncontrolled movements of the loop are likely to occur. a

The several features of the present invention 0 will be clearly understood from an inspection of the accompanying drawing, in which Fig. 1 is aview in front elevation of so much of a lockstitch sewing machine as is necessary to illustrate the connection of the invention therewith; Fig. 2-isa detailed view in side elevation of a needle guideprovided with an extension illustrating the man ner in which the extension prevents a needle loop just freed from the loop taker from becom.' ing caught on the needle or guide, the loop taker position being shown in dot-dash lines; Fig. 3 is a detailed view in frontelevation of the same parts of the machine; and Fig. 4 is a furthersimilar detail view on a somewhat enlarged scale.

The machine illustrated in the drawing, ex-

cept ashereinafter described, is the same in all essentials as the machine of the Ashworth patent.

above identified. The rotary hook is indicated at 2, the locking thread case at 4, the curved needle at'6, the needle guide at 8 and the loop spreader at ID. The rotary hook is located to rotate in a plane at right angles to the plane'defined by the path of the curved needle. The rotary hook has an open end at the front of the machine and the locking thread case a closed end exposed at the rear of the loop taker at the side adjacent the needle. Each needle loop, as indicated at l2, after being drawn through a perforation in the work l3 by the needle, is lifted by the spreader I0 and presented to a beak M on the loop taker. The outer leg of the needle loop which engagesthe outer surface of the beak I4 is supported in front of the loop spreader, as in Fig. l of the drawing, and the inner leg engaged by the inner surfaces of the loop taker, as illustrated in this figure, is still retained in the barb of the needle. The thread case has a suitable supply of locking thread It, the outer end of which extends towards thread case and to free the needle loop with a substantial length remaining outside the Work, and a needle guide provided with an extension projecting to a point at-a greater distance from the work than the length of the needle loop at the time the needle loop is being freed from the loop taker to prevent the loop from catching on pass it about the thread case, the outer leg of the loop passing across the exposed inner end of the thread case and the inner leg passing between the thread case and the loop taker without encircling the thread case. In so doing, a 180 twist is imparted to the needle loop and it is in this relation that the needle loop is drawn from the thread case and loop taker into the 'Work. To avoidthe possibility that the outer leg of the loop will become caughton the barb of the needle, while the loop is being carried about the thread case, the needle guide is formed in a manner similar to the needle guide of the Ashworth patent with a surface I8 extending at'both sides of the plane of the needle but in the present guide, the distance between this surface and the needle is somewhat greater than the corresponding distance in the Ashworth patent to insure the desired results.

The needle guide in which the present inventionis embodied comprises a radial extension 'projecting at an angle from the end of the loop deflecting surface I 8' towards the loop taker so that it enters a narrow space between the side of the loop taker and an arm of the loop spreader l0 while the needle and guide are in positions corresponding to the point in the sewing cycle where the loop is being freed from the loop taker andth-read case. When theneedle loop is freed from the loop taker, the loop taker and loop are moving rapidly towards the Work, the needle loop having a substantial length extending outside the work, as indicated in Fig. 2. As a result of its rapid movement, there is a tendency for the needle loop to twist and fly in uncontrolled fashion in all directions, but the extension 20 on the needle guide projects to a point at a greater distance from the needle perforation in the work through which the needle loop passes than the length of the loop itself at this time so that it is impossible for the bight in the loop to-be carried] about the tip of the extension. Due to the location of the needle guide along the needle when the loop is freed from the thread case, there is no possibility of the loop becoming caught on the barb, the guide beingactuated to cover, at least partially, the open hock of the needle, as indicated in Fig. 2, at the; time of freeing theneed'l'e-loop from the-loop taker.

By this construction and arrangement, the useand expense in manufacture of a separate guide finger, as in the machine of the Ashworth patent above referred to, with its accompanying difficulties of adjustment, and all possibility of catching the needle loops on the needle and guide are avoided.

Having thus described the invention, what is claimed is:

I. A lockstitch shoe sewing machine having stitch'forin-ing devices including a curved hook needle, a locking thread case, a loop taker acting to pass each loop of needle thread about the the needle guide.

2. A lockstitch shoe sewing machine having, in combination, stitch forming devices including a curved hook needle, a locking thread case, a loop taker acting to pass each loop of needle thread about the thread case and to free the loop with a substantial length remaining outside the work, a loop spreader arranged to lift each loop from the needle and present it to the loop taker, and a needle guide provided with an extension project'- ing to a point at a greater distance from the needle perforation in the work than the length of needle loop at the time the needle loop is being freed from the loop taker to prevent the loop from. catching on the needle guide.

3. A Iockstitch shoe sewing machine having, in combination, stitch forming devices including a curved hook needle, a locking thread case, a loop taker acting to pass each loop of needle thread about the thread case and to freethe loop with a substantial length remaining outside the work, a loop spreader arranged to lift each loop from the needle and present it to the loop taker, and a needle guide provided with an extension projecting between the loop taker and an arm of the loop spreader at the time the loop is being freed from the loop taker to prevent the loop from catching on theneedle guide.

4. A. lockstitch shoe sewing machine having, in combination, stitch forming devices including a curved hook needle,v a locking thread case having an. exposed end directed towards the needle, a rotary loop taker acting to twist each loop of needle thread and carry one leg thereof inside the loop. taker betweenth'e loop taker and the thread case and the other leg outside the loop taker across the exposed end of the thread case, and a needle guide'provided with a surface on both sides of the needle for deflecting the outer leg of i the needle loop away from the open hook of r the needle While leaving the needle hook free to' release the inner leg of the loop, and an extension on: the needle guide projecting at an angle to the deflecting surface to prevent the loop from being caught on the needle guide.

5. Alockstitch shoe sewing machine having, in

combination, stitch forming devices including a curved hook needleia loclzing thread case having an exposed end directed towards the needle, a rotary loop taker acting to twist each loop of needle thread and carry one leg thereof inside the loop taker between the loop taker and the thread case and the other leg outside the loop taker across the exposed end of the thread case, a loop spreader arranged to lift each loop from the needle and present it to the loop taker, a'

needle guide provided with a surface on both sides of the needle for deflecting the outer leg of the needle loop away from the open hook of the needle while leaving the needle hook free to re-' lease the inner leg of the loop, and an extension on the needle guide projecting between the loop taker and an arm of the loop spreader while the loop is being freed from the loop taker to prevent the loop from being caught onthe needle guide.

FRED ASHWORTH.

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