DE1485341A1 - Chain stitch device for lockstitch sewing machines - Google Patents

Description

DREWiEGAND 2000 hamburgi, July 27, 1964 MDNCHEN BAUINDAMM2 « DIPL-ING. W. NIEMANN phone 33 04 75

HAMBURG

PATENT LAWYERS ·. H853A1

W. 21297/64

The Singer Company, Elizabeth, New Jersey (V.St.A.)

Chain stitch device for lockstitch sewing machines.

The invention relates to sewing machines and, more particularly, to devices for converting a lockstitch sewing machine in a chain stitch sewing machine.

It is an object of the invention to provide devices with a lockstitch sewing machine Can be connected to convert the machine for making chain stitches.

Another object of the invention is to provide a simple and effective chain stitch converting device of the type mentioned above, which are applied to instrumentalities producing double lock stitches which contain a needle, a looper, a needle thread take-up device and a cloth pusher device, and those unchanged in their structure or compared to the cooperating Location remain unchanged as they are for the

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Production of lockstitch is required.

Another object of the invention is to provide chain stitch converting devices of the above Art to create, which can be applied to instrumentalities producing double lockstitch, in which the bobbin on which the looper or interlock thread for the production of lock stitches is stored, can remain in place in the looper feed a locking thread for incorporation into the chainstitch seam.

Another object of the invention is to provide chain stitch converting devices To create of the type mentioned above, which are particularly suitable for use in a lockstitch sewing machine, which one use grippers moving on a circular path around a vertical axis.

In the drawing is a preferred embodiment the invention for example brought to the display. Fig. 1 shows an end view from the head end of a Lockstitch sewing machine in which the machine arm cover plate is removed and Parts of the base have broken off to reproduce the stitching instrumentalities, to which the chain stitch converting device used according to the invention wid. Fig. 2 is a plan view on an enlarged scale

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part of the Apbeitsstücktragfläche the Mähraaachine the Pig. 1, in which the throat plate and the base slide plate are removed, in order to remove the stitching instruments to expose within the base.

FIG. 3 is a perspective view of portions of FIG Stitching instrumentalities of the Pig sewing machine. 1 with the chain stitch converting device according to the invention »and it contains both the needle thread and the bobbin thread and includes the production of a chain stitch seam • in a locking thread again.

Flg. Fig. 4 is a perspective view of portions of the still picture instrumentalities of the sewing machine Fig. 1 with the device for converting to chain stitches according to the invention, including only the needle thread, it gives the Location of parts and thread as needle penetration occurs during chain stitch production again.

Figure 4a is a vertical cross-sectional view according to Line 4A-4A of FIG. 4.

FIG. 5 is a perspective view of portions of FIG Stitching instrumentalities of the sewing machine similar to that of FIG. 4, but in which the Position of parts and the thread shortly after

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of - ;: g.; nal inspected

capturing the needle loop while making chain stitches. Fig.5a is a vertical cross-sectional view according to

Line 5A-5A of FIG. 5.

Fig. 6 is a perspective view of parts of the stitching instrumentalities of the sewing machine similar to Fig. 4, but in the position of parts and thread as the needle moves upward and after the detected needle thread loop has been released from the hook point, and
Figure 6a is a vertical cross-sectional view taken along line 6A-6A of Figure 6.

The invention enables a conventional lockstitch sewing machine to be converted into a single-thread chainstitch sewing machine. Fig. 1 shows a side view of the head end of a conventional household lockstitch sewing machine, on which the invention can be used.

The sewing machine housing has a base 11, from which a stand 12 stands up, the one Machine arm 15 hanging above the base 11 carries. One Main shaft 14, which in the longitudinal direction in the machine arm 13 is mounted, drives all the moving parts of the sewing machine, and it can be powered by an electric motor (not shown), by a pedal or the like. be operated.

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A balanced crank 15 on the main shaft 14 is operatively connected by means of a drive link 16 to a needle bar 17, which can be pushed back and forth in a bearing 18 in the machine arm 13 in the longitudinal direction, and at its lower end a pointed needle 19 provided with an eye wearing. The crank 15 also actuates a needle thread take-up lever 20, the movement of which is limited by an anchoring link 21. M.

The path of a needle thread leads from a (not shown) Supply to a thread tensioning device 22, through an eye 23 in the thread take-up lever 20 and then through appropriate Guides, e.g. the thread guide 24 on the needle bar 17 and to the eye of the needle. This needle thread control device is typical of the type required for the production of lockstitch. The usage of Conversion devices for chain stitches .n; em according to the invention works in conjunction with these double lockstitch needle thread controls successfully. ™

In the base 11, a gripper is mounted on a gripper shaft 30, which is generally designated 3I. Of the shown in the drawings gripper 3I is a rotating one Gripper with a vertical axis (horizontal gripper), which with each up and down movement of the needle 19 two Rotations. The gripper 3I is in the form of a basket Body part 32 is provided which is provided with an inwardly extending loop-engaging tip 33

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is what thread loops from the needle 19 capture and which, as shown in Fig. 2, moves back and forth in a path which within the bowl-shaped Gripper body part 32 is located.

A bobbin case 34 is mounted within the gripper body part 32 and is held against rotational movement therewith by means of a structure 35 which prevents corrosion and which has a spring 36 which engages with an abutment 37 on the bobbin case 34. A coil 38 is within the coil housing 34 intake and can move freely, wherein the lower or locking thread from the spool 38 as shown in Fig. 3, 39 is the bobbin case y \ subjected to the action of a leaf spring on the thread to apply a voltage.

The needle I9 and the looper 31 can, as far as described, Make double lockstitch in the usual way. The loop-gripping tip 33 of the gripper 3I occurs engages with needle thread loops and carries them completely around the bobbin case 34, and therefore contributes the needle and bobbin threads are linked to real double lock stitches (Federal type = ^ = 30I) for each needle stitch. The gripper 31 can be rotated twice by means of a shaft 40 in the stand 12 for each needle up and down movement which is driven by bevel gears 41 from the main shaft 14, and in turn via bevel gears

9 0 9 8 2 7/04 41 Oi-; ^ μλι. i- ^ fücted "

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is connected to a base shaft 4}, which is the Grelfcrwelle 30 drives through a set of bevel gears 44.

As shown in Fig. 1, there is a cloth feeding device one with four movements or with one movement downwards. One attacking the work piece Knife pusher 50, which works through slots 51 in a throat plate 52 on the base 11, is screwed 53 with a material slide support beam 54 below the

Base 11 firmly connected. Feed and return movements are the material slide support beam 54 by a swinging Feed swing shaft 55 issued, which is connected to the feeder support beam 54 by means of a swing arm 56 is. The oscillating feed shaft 55 is controlled by a feed cam 58 by means of conventional connections 57 in the stator 12 pivoted on the main shaft 14. The connections 57 can contain a conventional control device 59 to control the To change the stitch length. Lifting and lowering movements are made to the material slide support beam 54 by a swinging forward | thrust lift swing shaft 60 in the base 11 granted. The feed stroke oscillating shaft 60 is provided with a swing arm 61, which by means of a link 62 with the material slide support beam 54 is connected. The feed stroke oscillating shaft 60 is secured in the stator 12 by means of conventional connections 63 pivoted on the main shaft 14 by a feed stroke eccentric 64. As is customary in technology, this is Fabric feeding device for needle reciprocation

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timed so that the knife gate valve 50 is raised and advanced while the needle 19 is out of a work piece is moved up on the needle plate 52, and the feed valve 50 is lowered under the needle plate 52 and returned while the needle 19 is following moved down.

According to Fig. 2, the conversion device to the lockstitch sewing machine explained above for the Sewing chain stitches suitable to make one with the

Thread loop engaging finger 70, which is located below the needle plate 52 and substantially parallel to the needle back-and-forth movement path between the needle path and the bobbin case 34 is downward. Of the with the thread loop in engagement finger 70 is carried on a leaf spring 7I, which extends from a Support arm 72 extends, for example by screws 75 on the base 11 is attached. The bearing arm 72 is with a down directed stepped part 74 provided, which is attached to a Side of an access opening 75 in the base 11 is provided is, and this access opening 75 exposes the gripper 31. The deposition 74 of the bearing arm 72 is preferably on the Junction of the throat plate 52 and a cover slide plate 76 arranged, which the access opening 75 locks. The stepping with the thread loop finger 70 is by the leaf spring 7I against a Abutment projection 77 pressed, which on the bobbin case J4

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and is arranged between the axis of the gripper 51 and the movement path of the needle 19.

As in the Pig. 2-6, the knife gate valve 50 is between the reciprocating path of FIG The needle 19 and the pinger 70, which is in engagement with the pad loop, are provided with a cross brace 80 which extends therefore moved up and down with the feeder valve movements and always a position above the J. . Thread threading * fen which are manipulated by the gripper 51 assumes.

4 to 6 and 4a to 6a show the sequence of handling the thread in the production of single-thread chain stitches again using the conversion device according to the invention.

In order to prepare the lockstitch sewing machine for sewing chain stitches, the bearing arm 72 must be connected to the fingers 70> holding the thread loops be attached to it on the base 11, as shown in Fig. 2, so that the finger 70 against the abutment projection 77 of the |

Bobbin case 54 is pressed / a throat plate for a conventional lockstitch sewing machine is usually provided with a round needle hole for the needle. Chain stitches can be made using a round needle plate needle hole; however, there solidification of a chain stitch involves a relative movement of the thread through the previous stitch, it is preferable to the stitch plate, which is usually used for double quilting

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Stitches used is through a similar needle plate too replace, which differs only in that a tap hole 85 is provided, which in the direction of the advance is elongated.

4 and 4a show the position of parts and the thread when the needle pierces through the workpieces and through the needle hole 85 in the needle plate. A loop of thread A from the previous needle puncture extends through the needle hole 85 and tightly around the loop-engaged finger 70 which is pulled away from the abutment projection 77 by the loop of thread A. The spring constant of the leaf spring ¹ J ^ is preferably selected so that it corresponds to the tension in the thread

the

loop A yields while the previous stitch has solidified.

In FIGS. 4 and 4a, the knife valve is located 50 in its rear position and has just finished a feed and continues to fall in preparation for a return stroke down. The strut 80 therefore catches begin to push down on the loop of thread A so as to engage the loop of thread A from the one with the loop to strip standing finger 70 after the needle I9 has passed through the thread loop A.

5 and 5a show the position of the parts and the Thread again when the needle comes out of the workpiece. The loop gripping tip 53 of the looper has

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a new loop A ¹ of needle thread is detected, and the strut 80 of the fabric slide 50 strips the previously formed thread loop A from the pinger 70 engaged with the loop. The feed valve 50 has moved against the bobbin case Jk and is in the position that it is raised for a feed stroke.

The Pig. 6 and 6a show the position of the parts when the needle is essentially at the top of its stroke A. The pinger 70 engaging with the loop has moved into engagement with the abutment projection 77 by the leaf spring 71. The new thread loop A ¹ , when sfe is thrown from the loop gripping tip 35 of the looper 31, is carried by the abutment projection 77 by being tightened around the finger 70 engaging the loop. The thread loop A previously formed is through the manipulation the new thread loop A * in size somewhat reduced, but the previous thread loop A is not detected \ drawn against the workpiece to solidify the stitch unless the needle thread take-up lever 20 the new thread loop A ¹ on the attracts the loop-bearing finger 70th When this occurs, the thread is arranged as shown in Fig. 4 and ready for the subsequent penetration of the needle 19.

Since the spring 71 returns the finger 70 carrying the loop against the abutment projection 77, the

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The risk that the loose pad loop A ¹ accidentally slides under the pinger 70 carrying the loop is avoided. The only influence which moves the pinger 70 carrying the loop away from the abutment projection 77 is the tension in the thread. However, once the loop of thread is pulled taut around the finger 70 carrying the loop, the friction prevents it from sliding off, and the strut 80, which serves as a stripping member, is necessary to forcibly move the loop of thread away from the finger 70 carrying the loop.

Fig. 3 shows the position of T _e ile and the resulting seam, which is formed if a thread-carrying coil disposed in the coil case k J> 38th The bobbin thread B is not firmly consolidated with the needle thread, as in the usual double lockstitch production, since the stitch consolidation is delayed in the production of chain stitches. The bobbin thread B is, however, linked to the needle thread in order to lock the chain stitches against the crumbling legs. The bobbin thread B, which runs loosely through the resulting chain-stitch seam, can be conveniently pulled out of the seam in the longitudinal direction and leaves a pure chain-stitch seam that can be popped open as desired.

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Claims (5)

U85341 Claims. Sewing machine with stitch-forming devices, with a thread-guiding needle provided with an eye and a revolving gripper, which are driven in relation to one another in time, a bobbin housing with thread bobbin mounted in the gripper and held against rotational movement, as well as a workpiece feed device, thereby g indicates that for the purpose of creating chain stitches using the thread carried by the needle a with the needle thread loop in engagement part (finger 70) is provided below the work piece plate is on that side of the needle up and down movement path that faces away from the feed device is, as well as a suitably worn on the bobbin case (3 ^ 0 Thread guide part (77) is provided, which comes together with the part (70) engaging with the thread loop. men works to by the gripper (31) manipulated thread I loop on this part (finger 70) and between the part that engages with the thread (70) and a stripping member (80) for thread loops is arranged in the up and down movement path of the needle, which in temporal relationship to the up and down movement of the needle back and forth and towards the free end of the thread loop engaging part (70) is movable when the needle (I9) passes through the needle hole (85). 909827/044 1 OHSINALINSPECTcD 2. Sewing machine according to claim 1, characterized in that in the bobbin carrier (34) a thread-guiding bobbin (38) is arranged carrying a locking thread for interlinking with the chain stitches. 3. Sewing machine according to one of claims 1 - 2, characterized in that with the thread loop in engagement stepping part (70) mounted on the housing in the direction of the feed movement of the workpiece and after delivery a thread loop can be moved back into the starting position by a suspension (7I) « 4. Sewing machine according to one of claims 1 to 3 * thereby characterized in that the part (finger 70) engaging with the thread loop is removable on the sewing machine housing is stored. 5. Sewing machine according to one of claims 1 to 4, characterized in that the stripping part (80) for the Loop of thread from the part (70) which engages with it as a vertical direction and a temporal one Movement to the needle movable transverse part is formed, the with the four movements executing material slide connected is. 909827/0441