DE918547C - Lockstitch sewing machine with revolving hook - Google Patents

Description

Lockstitch sewing machine with revolving hook The invention refers to lockstitch sewing machines with a rotating hook, and on the lower stitch forming device.

After the invention of the revolving hook, the double lockstitch sewing machines were mainly looking for an increase in production by increasing the number of minute stitches, and even after years of detailed work, they were able to overcome the difficulties that occurred again. Man. has reached 30.00 or 5,000 stitches per minute.

When it came to the following: types of construction, the main focus was on the With the increased speed it is particularly difficult to pass through the needle thread loop through the limited cutout of the basket-like, fixed bobbin case comprehensive gripper. With this design of the mechanisms used one was forced other factors, which in connection with the increased speed of circulation also lead to an increase in production to the same extent, can be neglected. Because an increased stitch performance requires to achieve an actually increased Production also increases the thread take-up of the machine bobbin when it is not by replacing the expired machine bobbin, which increases to the same extent should be illusory. However, this enlargement of the machine reel is; in the mechanisms used are not feasible.

In practice, the high number of minute stitches in high-speed machines has the following effect: With a number of minutes of 3000 stitches, the seam length would be 3 = per minute with a stitch length of i mm, 4.5 m with a stitch length of 1/2 mm, and a seam length of 6 m with a stitch length of 2 mm generated.

The thread length on the machine bobbins that can now be used is im Average no more than 45 m. With a stitch length of 1 mm, the seamstress would have to do every 15 Minutes, with 1l / 2 mm stitch length every 10 minutes, with 2 mm stitch length every 7l / 2 minutes replace the empty machine spool.

This would be four times per hour with a stitch length of 1 mm, with 11/2 mm stitch length must be done six times, with 2 mm stitch length eight times.

When replacing this coil, the following steps are now required: Take out the bobbin case, take out the empty bobbin, put it on the bobbin winder and bobbin winding., Insertion of the full bobbin in the bobbin case, thread insertion under the brake spring, reinserting the bobbin case.

If you have this unreasonable loss of time, what a possible re-sewing the blind seam produced by the run-off bobbin must be expected with If 2 minutes are used, then with a stitch length of 1 mm the hour would be 8 minutes, with 8 hours 64 minutes, with 1l / 2 mm stitch length in the hour 12 minutes, with 8 hours 96 minutes, with 2 mm stitch length 16 minutes per hour, with 8 hours 128 minutes more daily Production downtime occurs.

Expressed as a percentage, this would be 13.3, 20 and 26.6 ° / o.

The higher the speed of the machine is increased without that the thread take-up of the machine bobbin is increased, the above percentages would be the inevitable loss of production and the desired increase in production become illusory.

Furthermore, the bearing rib of the gripper is for the carrier disk the bobbin case is extremely sensitive to the finest ingress of fiber dust, the lubrication of the same is cumbersome and easily contaminates the Sewing thread. It is therefore neglected and thus carries the risk of overheating, the seizing or jumping of the gripper in itself. To prevent the bobbin from rotating to secure with the gripper, it is common to provide the bobbin case with a groove, a tongue that prevents rotation of the bobbin case loosely enters, because is attached to the machine frame. Each dropped around the bobbin case The needle thread loop therefore measured the revolution between these contacting walls the bobbin case-preventing tongue and groove of the bobbin case go through, before this loop becomes free and can be tightened on the fabric.

By using a bobbin case located in the gripper, in which the machine bobbin with the bobbin thread is completely covered, , the sewing thread can only run through the blind seam that occurs when the bobbin is empty are noticed while sewing and is always felt to be unpopular.

The majority of garment factories, especially tricot and shirt manufacturers, have no advantage from excessive minute stitches, because with the short seam lengths the machine must come to a standstill immediately after a short start-up so that the full number of tours can never be achieved and also cannot be used.

Essential for increasing production in most garment factories is therefore with a usable circulation speed of 20oo to 30oo tours in the: Minute, the previously used mechanisms in the lower stitch! to be designed in such a way that I. by separating the gripper from the one previously connected to it The bobbin case simplifies the turning of the upper thread loop and thus the large one Sensitivity to penetrating fiber dust is eliminated, II. By using one: larger machine bobbin increases the thread take-up of the same and thereby the Replacement of the expired machine bobbins is reduced, III. by omission the mobile bobbin case now required, the replacement of the machine bobbin is accelerated, IV. the thread run-off through visible mounting of the machine bobbin observed by the same and thereby the disadvantageous & lind sewing is avoided, V. through. Simplification of the previously used mechanisms make the Manufacturing is achieved.

This object is to be achieved by the invention.

According to the invention, the gripper is outside of the machine spool receiving body, hereinafter referred to as the coil housing, arranged next to it, in such a way that the hook the needle thread grasped by it as a loop around the mentioned Bobbin case and thus under the bobbin thread. The gripper thus receives a from the previously usual semicircular or full-round shape of a hollow body, which only through Complicated manufacturing processes can be produced, completely different shape and no longer carries a bobbin case. Rather, he just sits on one revolving., freely cantilevered mounted shaft as an arm at the free end of the same.

The coil housing has a circumferential edge that is wedge-shaped in cross section so that the O'berfa @ den loop through the. Grab a branch with her one, with its other branch on the other side of the wedge edge of the bobbin case is placed. The edge, which is wedge-shaped in cross section, is only useful in the upper third the scope is available, the remaining part is removed; the bobbin case is included so gesteIllt that the loop after release by the gripper in the area of this Deposition is pulled up slightly.

The bobbin case is attached to its side by two pairs of support arms held outer stepped peripheral edge, which engage in recesses of the same and with their mutual evasion to create a passage for the front upper thread legs also alone the bobbin case in its immovable, hold upright position.

The back and forth swinging movement is carried out by these support arms each has a connecting bracket, which comprises a distance from a Mitnehmer.erwinke9 will. A headed connection bracket engages through the latter fixed driving pin around which a compression spring rests and the distance between fills the two angles by holding back on one and pressing on the other. The driver bracket is hinged to a movement lever, which is on the side of the bobbin case mounted oscillating shaft.

Behind the vertical retaining plate are on the main drive shaft two cams of 60 ° each and two curves of 80 ° each eccentric effect fixed, which with their revolving movement the forks gripping them into one back and forth make a swinging movement. One arm of each fork grips the cam and one arm of each fork on the curve, such that for the swinging motion .the support arms only the cams alternately exert their effect for the swinging Movement of the support arms only make the curves act reciprocally and on the other arm reach past the fork. Through this. causes the pairs of support arms to hold their Function of the bobbin case only alternately for 60 ° when the shaft is rotated give up for the upper thread passage.

The figures show an exemplary embodiment, namely: FIG. 1 the device from the side at the moment in which the needle thread loop slides off the gripper nose after a slightly more than 180 ° rotation of the same, FIG. 2 shows the front view of FIGS. 3 the horizontal. Middle section of FIG. 1 from A to A, seen from above, FIG. 4 the rear view of the movement mechanisms in partial section from B to B of FIG. 2, FIG. 5 the rear drive mechanism, FIG. 6 the vertical section of the drive mechanisms from D to D of FIG. 5, FIG. 7 the vertical section from C to C of FIG. I, FIG. 8 the partial section of the coil housing 5 and the foldable coil carrier arm 15 with support at the moment in which the hook tip i 'grasps the needle thread loop, Fig. 9 to ii the folding of the needle thread loop around the bobbin case after 90 ° and more than 180 ° rotation of the hook, Fig. 12 to 14 the mechanisms 21 and 26 from above, seen from the front and the rear, FIGS. 15 and 16 the gripper nose seen from the front and the gripper i seen from the rear.

The gripper i is in the form of an arm at the free end of the gripper shaft 2 'attached, freely projecting in a vertical holding plate 3 of the machine base is stored. The arm-shaped gripper i, which is cranked at an obtuse angle, is located next to a housing 5 receiving the coil S, hereinafter referred to as Coil housing is designated. The bobbin thread 6 is out of the bobbin case 5 through a sliding hole of the foldable coil support arm 15 is led out. Through the throat plate 7, the needle 9, which guides the needle thread io, occurs in the usual manner.

The coil housing 5 has a wedge-shaped cross section on its circumference Edge i i, whose two wedge surfaces in the upper third of the bobbin case 5 through the wedge edge 12, the remaining part expediently by flattening the wedge edge 12 are separated. The wedge edge 12 and the flattening are concentric on the inside the circular movement path to be covered by the nose of the gripper i.

In order to keep the coil S inserted into the coil housing 5 visible, the same is open at the top, so that the coil S both over its diameter and is visible in its length dimension, with a rear wall 14 of the coil housing 5 serves as a stop to prevent the coil S from sliding off the carrier pin 15 '. Front of that Spool housing 5 is a collapsible spool support arm 15 with a spool support pin 15 'attached, on which the spool S rotates.

The bobbin case 5 is facing the needle 9! Or @ w. the gripper i so that the needle thread loop 16 of the upper thread grasped by the hook point i '(Fig. 8) by the circular movement of the arm-shaped gripper i from the position of Fig. 8 is placed in that of Fig. 10 around the bobbin case 5, with one branch 16 ' the upper thread loop 16 on one side, the other branch 16 ″ of this loop on the other side of the wedge edge 12 comes to fly. Will loop 16 through the gripper i is released, which position is shown in Fig. i and i i pulled them up through the thread yellow. The upper thread loop is then. under the Bobbin thread 6 placed, as required to produce the lockstitch seam is.

The storage of the coil housing 5 takes place on both sides of the same by a pair of movable support arms 17, which swing in articulated levers i9, the protruding horizontally from the vertical retaining plate 3 above and below Straps 2o are hingedly attached.

The support arms 17 engage on both sides of the bobbin case 5 with their pins 30 in recesses 18 (Fig. 4) of the same so that the opposing action of the upper and lower support arm 17, the pins 3o clamp eccentrically on the wall of the recesses 18 and thereby hold the bobbin case 5 in its vertical position.

When the entire device is moved, the two sides swing Support arms 17 reciprocally back and forth, the pins 3o holding their function Exercise in the recesses 18 of the bobbin case 5 sliding in and out alternately or give up to for the upper thread leg 16 'each to create a passage. The coil housing 5 is also supported by a pair of carriers 17 held in its vertical position.

When the device is at a standstill, the machine spool has to be replaced this holding function exercised on one side by a pair of carriers 17 in their over the limited engagement in the recesses 18 of the coil housing 5 addition. eccentric clamping effect reinforced by the compression spring z9. For this purpose are the support arms 17 at its outer end according to their arrangement by the screws 22 with the connection bracket 21 (Fig. 13) hinged, which with its recess 23 includes the support pin 24 of the movement lever 25 and slides on it.

Behind the connecting bracket 2-1 is, articulated to the support pin 24, the driver bracket 26 (Fig. 14), the angle 26 'of which includes the angle 21' at a distance (Fig. 12). The driver pin 27 provided with a head (FIG. 2) is fixed at its end with the angle 21 'and slides through the hole 2.8 (FIG. 13) of the angle 26'. The distance between the angle 21 '(Fig. I) and the angle 26' is filled by the compression spring 29, -which, lying around the driver pin 27, has its support at the angle 26 'and exerts its pressure on the angle 21' (Fig. 13).

It is thereby achieved that the support arms 17 hinged to the connecting bracket 21 through the existing recess 23, which only slides on the support pin 24, are limited by the pressure of the spring 29. Engagement of their pins 30 in the recesses 18 of the coil housing 5 also obtained an eccentric clamping effect.

The carrier pin 24 is fixedly attached to the lever arm 25 (Fig. 7), this on the side of the coil, housing 5 in the vertical retaining plate 3 of the Machine base mounted oscillating shaft 31, which their oscillating movement through the free end protruding from the rear of the holding plate 3 the rocker shaft 31 seated lever 32 (Fig. 5) receives.

On the main drive shaft 2 sit two cams 33, 33 '(Fig. 5 and 6) of 60 ° each and two curves 34, 34 'of 180 ° each, which have two a common axis 35 (Fig. 6) pivotably arranged forks 36, 36 '(Fig. 5) set in a pendulum motion, whereby one arm of each fork is only attached to the cam, the other arm of each fork only grabs the curve. This ensures that the holding function of the support arms 17 extends to 3oo °, the task of holding Function of the support arms 17 is limited to 6o °.

One arm of the forks 36, 36 '(Fig. 5) has a lateral projection, on which the connecting lever 37 is hinged to the lever 32 and .auf this is transmitted by the oscillating movement of the forks 36, 36 '. The foldable bobbin arm i5 is slightly extended at the top beyond the bobbin case 5 (Fig. i) and into the Inside of the same over the coil S angularly reinforced, 39 (Fig. 8), flattened upwards. This extension and reinforcement has the task of having reached the lowest point When the needle retreats, it tightens the upper thread next to the flattening the outside of the needle and thus the looping of the upper thread to secure the inside for the engagement of the hook point in the loop.

On the inside of the projection 4o (Fig. 4) of the foldable arm 15, the bobbin thread tensioning device 41 (FIGS. 8 to 11) is attached. In contrast to the previous unwieldy thread tensioning device by a leaf spring up the bobbin case is conveniently adjustable in the same way as the normal upper thread tensioning device with only one clamping disc 42, a compression spring 43 and the regulating nut 44 held. The bobbin thread is guided to the outside of the bobbin case 5 through a sliding hole (Fig. i).

The pivoting of the arm 15 is due to the bottom of the bobbin case 5 attached .Gelenk 45 (Fig. 8) allows. Above it is on Joint of the inside of the arm 15 has a flattening 46 on which the inside of the Spul.engehäuses 5 fixed leaf spring 47 pushes the arm 15 in its vertical Holds position. The arm 15, which has been folded through 90 °, is supported by the fixed holding plate 3 attached rash 48. To limit the flying movement of the needle thread loop 16 of the gripper nose i 'serves the protective part 49 (Fig. I).

The protruding gripper nose i '(Fig. 16) moves at their circular trajectory to be covered concentrically over the edge of the wedge 12 and their flattening of the bobbin case 5, so that after detecting the upper thread loop 16 (Fig. 8) by the gripper tip i 'during the further rotation of the gripper i the same slides back under the gripper nose i 'to the approach 5o (Fig.16). Has the projection of the looper nose i 'the task of keeping the upper thread loop 16 wide, so that the branch 16 "of the same through the wedge edge i2 on one side, the branch 16 'to the other side of the edge i i of the coil housing, which is wedge-shaped in cross section 5 comes to rest. A sliding of the branch 16 "of the upper thread loop 16 after Side beyond the hook nose i 'prevents the small extension 51 (Fig. 15 and 16) of the gripper arm i, the sliding of the branch 16 'under the gripper nose -'beindliche approach 5o (Fig. U and and 16).

The gripper nose i 'is expediently forward at its rear end so rounded, 52 (Fig. 15 and 16) that the upper thread loop 16 after rotation of the Gripper i can easily slide forward from the same by more than 90 °.

As can be seen, there is first a significant improvement in accordance with the invention in that the gripper of. the Spu.lengehäus.e is completely separated, whereby the upper thread loop no longer over the looper or through the cavity same between the bobbin disc experiences its assignment, but next to the same. This increases the sensitivity of the machine to penetrating or inevitable threads Fiber dust into the groove of the gripper for the flange of the spool carrier disc, there is also the risk of the gripper overheating or jumping if the gripper is defective Oiling of the groove completely eliminated. The elimination of the multifaceted mechanisms the previous gripper and the Spu: steering capsule caused an increase in the movement mechanisms, however, they are limited to short-swinging levers, making a fairly Noiseless gear with little oiling and wear is achieved. The machine spool can be replaced without special care even if the needle is is in its lowest position.

Another valuable improvement according to the invention over the Machines now being created means that by keeping the bobbin case open visible thread run-off from the machine bobbin, the handy replacement - the same thanks to the foldable bobbin support arm 15 and the practical bobbin thread tensioning device41. According to the invention, the individual parts of the device are also simplified, whereby the production is cheaper. The functioning of the same can, as all Elements are exposed, can be observed at all times and is also available to the layperson. understandable. The machine coil, which has been enlarged by 5o% compared to the previously used ones, increases the Automatic performance of the machine due to the increased thread take-up and less frequent replacement of the expired machine spool.

Claims (13)

PATENT CLAIMS: i. Lockstitch sewing machine with a one loop of the upper thread around the bobbin thread, continuously revolving looper, thereby characterized in that the gripper is mechanically arranged separately next to the bobbin case is, the circumference of which it revolves with its protruding nose. 2. Sewing machine according to claim i, characterized in that the coil housing has a has wedge-shaped circumferential edge in cross section, so that the circumferential gripper nose the upper thread loop with its one branch on one branch, with its other branch on it the other side of the wedge edge in the upper third of the bobbin case. 3. Sewing machine according to claims i and 2, characterized in that the diameter of the coil housing and length dimension of the bobbin is kept open at the top, so that the thread run off can be observed from the bobbin, leaving a rear wall as a bobbin holder is. 4. Sewing machine according to claim i to 3, characterized in that on. the front On the side of the bobbin case there is a bobbin support arm that is slightly extended and foldable over the same (15) is attached to the bobbin carrier pin (15 ') for the bobbin. 5. Sewing machine according to claims i to 4, characterized in that the foldable bobbin support arm (15) has an inwardly reinforced projection on its upper left side, which serves to accommodate the bobbin thread tensioning device on its inside and to secure the loop formation of the upper thread for the engagement of the looper point. 6. Sewing machine according to claim i 'to 5, characterized in that the thread tensioning device for the machine spool consisting of a tensioning disc, compression spring and adjustable by hand Regulating nut. 7. Sewing machine according to claim i to 6, characterized in that that the Spulenge'häuse is diagonally opposite in its edge, which is wedge-shaped in cross section each has two recesses, in each of which a pair of pins from support arms (17) - Intervene so that each of them alone the Spulenge'häuse (5) in its vertical Can hold position. B. Sewing machine according to claims i to 7, characterized in that that the carrier arms (17) sit in swinging levers (19) which are articulated over mechanical intermediate links of eccentrics (33, 34) can be moved out. G. Sewing machine according to claims i to 8, characterized in that that two cams (33, 33 ') and two cams (34, 34) sit on the gripper shaft, the two forks (36, 36 ') pivoted on a common axis (35) set in a pendulum motion, so that one arm of each fork only with the cam, the other arm of each fork only works with the curve, with each fork (36, 36 ') via a connecting lever (37) assigned to it on an oscillating shaft (31) sit - the lever (32) and thus its oscillating shaft (31) oscillating movements issued, which are transferred from the oscillating shaft (31) to another lever (25) that its movement in turn via a driver bracket (26), a connecting bracket (21) conveyed to the carrier arms (17) connected to the latter articulated. ok sewing machine according to claims i to 9, characterized in that the angle arm (26 ') is the angle arm (21 ') includes at a distance, the distance by a compression spring (29) with the task is filled in via the connecting bracket (21) against the driver: bracket (26) the retaining pins (3o) of the support arms (17) after their engagement in the recesses (18) to give an eccentric clamping effect. i i. Sewing machine: according to claim i Abis io, characterized in that the gripper is arm-shaped cranked and the gripper nose (i ') is designed expansively, furthermore an approach (5o), a Extension of the gripper arm (51) and a rear rounding that runs obliquely forwards (52) owns. 12. Sewing machine according to claim i 'to i i, characterized in that that the foldable: bare coil carrier arm (15) after its swiveling out by 9o ° from a stop ($ 4) is supported. 13. Sewing machine according to claim i to 12, characterized characterized in that to limit the flying off movement of the needle thread loop from the hook nose at the bottom left next to the bobbin case (5) a protective part (49) is appropriate.