CN1507512A - Device for changing the bobbin of a looper thread on a sewing or embroidering machine - Google Patents

Abstract

The invention relates to a device for changing a bobbin-carrying bobbin case in a double-lock stitch sewing or embroidery machine, the bobbin case being supported by a journal arranged in a shuttle hook, the device comprising a receiving device having a carrier for the bobbin case comprising a plurality of receiving positions; and comprising a gripping device with at least one holding element for the bobbin case, which can be displaced along a predetermined guide path for changing the bobbin case between the receiving device and the shuttle, wherein the holding element (34) has at least one controllable magnet (35) contacting the bobbin case (4), and each bobbin case (4) has, in the region of its end face wall (7), a permanent magnet (8) acting as a locking element and cooperating with the journal (6), the holding force of which on the journal (6) is smaller than the force of the controllable magnet (35).

Description

Devices for changing loop bobbins on sewing or embroidery machines

technical field

The invention relates to a device according to the preamble of claim 1 for changing a loop bobbin on a double lock stitch sewing or embroidery machine.

Background technique

Double lock stitch sewing machines generally have a shuttle that includes a shuttle tip that grips the needle thread loop and an inner housing mounted in the shuttle that has a bobbin case received therefrom. The inner casing is provided with a journal concentric to the axis of the shuttle. When the bobbin casing is inserted into the inner casing, the journal is embedded in a hollow cylinder arranged in the bobbin casing. Shuttle.

In order to fasten the bobbin case to the journal of the inner housing, the journal is provided with a recess in the region of its free end, into which recess a stop provided thereon engages in the bobbin case inserted into the inner housing. The stop lever is displaceable on the bobbin case against the force of the spring and has an opening for the passage of the journal which is larger than the diameter of the journal by a predetermined amount. The stop bar thus secures the bobbin case in its end position against falling out of the inner housing and can be moved against spring force until it is disengaged by means of a stopper swingably arranged on the bobbin case and movably connected to the stop bar. Another end position of bobbin case, can take out bobbin case from inner case or shuttle in this end position. In order to prevent the bobbin from falling off the bobbin case in this position of the stop bar and thus not only during the insertion process but also during the removal of the bobbin case, a substantially right-angled flange is provided on the stop bar, which passes through the Holes provided in the walls of the bobbin case extend into its interior cavity and prevent the bobbin from falling off the bobbin case.

In order to facilitate the handling of the catch, its free end is bent out of the bobbin case a little and is easier to be grasped behind by the operator for removing the bobbin case from the inner case and inserting it into the inner case.

Since the bobbin can accommodate only small lengths of looped thread and therefore requires frequent replacement of the bobbin and the removal and reinsertion of the bobbin case associated therewith, known devices for changing the bobbin or bobbin case are imitated by technical means Change the bobbin by hand.

A device for changing the bobbin case is described in JP 8-196 766. It has a hook held by a movable bracket, which engages behind its catch for removal of the bobbin case and gives the catch a swing corresponding to a manual movement, the catch at its end touching the bracket constitute a relative position. A corresponding transverse movement of the catch lever is thereby achieved, whereby the bobbin case is disengaged and can be removed together with the bobbin from the inner housing by means of a carriage movable on a predetermined guide rail. Wherein the moving guide is designed so that it positively guides the carriage and first performs a movement positioned parallel to the axis of the shuttle, then turns to swing, followed by a movement directed downwards obliquely, at the end of which the bobbin case is handed over into the receptacle provided below and to the side of the shuttle.

Insertion of a bobbin case equipped with a filled bobbin into the inner housing is achieved analogously to this.

Since the bobbin case is thus not only in the process of moving from the shuttle to the receiving device, but also in the process of moving from the receiving device to the shuttle, it is only force-locked by means of the hook. Therefore, the hook must be locked during such a movement. Puts considerable pressure on the flap for the entire duration.

Also in the device according to US-PS 5 718 181, in order to grab the bobbin case, it is provided with a hook that engages its catch at the back, which is similar to the device according to JP 8 196 766 where the catch is moved from the shuttle to the bobbin case. During the movement into the receiving device or from the receiving device into the shuttle, it presses against a corresponding stop. Since a tongue is simultaneously formed on the stop, which engages in the groove provided on the stop when the stop is in its end position, the retaining of the bobbin case is partly form-locked and partly locked during its above-mentioned movement. This is effected force-lockingly.

The disadvantage here is also that the transfer of the bobbin case from the hook to the receptacle and from the receptacle to the shuttle takes place in a number of different motion phases, so that the device is also relatively complex, and moreover it also mimics the manual replacement of the bobbin case.

Finally, another device is known from DE-PS 1 206 713 for the mechanical replacement of the bobbin case in a double lock stitch sewing machine comprising a shuttle that rotates in a vertical plane, wherein the bobbin case moves along a direction parallel to the axis of the shuttle. The guide rail is removed from the shuttle and guided to a receiving position of the receiving device. Wherein as bobbin replacement device, be provided with an electromagnet which is movably arranged on the shuttle axis and a slide plate which can move together with it and is elastically connected with the electromagnet. The electromagnet deflects the bobbin case stop and thereby releases the lock between the bobbin case and the shuttle case on the one hand and locks the bobbin inside the case on the other hand, so that when the bobbin case is subsequently pulled out, the bobbin It is impossible for the heart to fall out of it.

In this regard, the principle of removal in DE-PS 1 206 713 is only to simulate the manual replacement of the bobbin case by means of a mechanical device.

Regarding the earlier previously unpublished DE 199 13 043 A1, a device of the same type is proposed for a double lock stitch sewing machine and a bobbin case adapted thereto, wherein the locking plate and the operation thereof which are later common are omitted The bobbin case stop used is replaced by a double-leg spring or an elastic ring inserted in a recess of the journal. Although this simplifies the construction of the bobbin case somewhat, the structural complexity for the movement of the holding elements of the corresponding gripping device is increased.

Contents of the invention

It is therefore the object of the present invention to develop a device of the same type in a targeted manner in such a way that on the one hand it simplifies the handling and holding of the bobbin case and on the other hand it reduces the structural outlay for changing the bobbin.

This object is achieved in a device of the same type in that the retaining element of the grabbing device has at least one controllable magnet that contacts the end wall of the bobbin case, and each bobbin case has in the region of its end wall a A permanent magnet acting as a locking element and cooperating with the journal has a retaining force on the journal that is less than the force of the controllable magnet.

The insertion of a permanent magnet into the end wall of the bobbin case creates a magnetic clamping force between it and the end of the journal of the inner housing, which ensures sufficient axial fixation of the bobbin case in the shuttle. It is thus possible to dispense with a later recess provided in the region of the free end of the journal. As long as the permanent magnet is inserted into the front wall of the bobbin case such that its surface extends substantially flush with the outside of the front wall of the bobbin case, the possibility arises that the position of the bobbin case in the receptacle is also secured by the permanent magnet.

Known from DE 198 40 956 C1 is a shuttle for a double-lock stitch sewing machine, in which the bobbin case can be taken out of the shuttle by means of a manually operated removal device made of steel. For this purpose a magnet is inserted into the end wall of the bobbin case 4, so that the bobbin case 4 can be removed from the shuttle by means of the removal device due to the magnetic field prevailing between the bobbin case and the removal device. Wherein there is enough control force to set out between take-out device and bobbin case 4, so that bobbin heart remains in the bobbin case in the process of taking out bobbin case, thereby bobbin case can be taken out simultaneously with bobbin heart all the time.

This solution is problematic in terms of sewing technology, because the magnetic field strength from the magnet inserted into the bobbin case 4 also acts on the bobbin during sewing, so that its rotation required for unwinding the yarn is braked. This results in different yarn unwinding forces.

According to another proposal of the invention, when the retaining element has two controllable magnets, during the movement of the gripping device it is possible to achieve The reliable positioning of the two magnets is in contact with it at positions diametrically opposed to each other on the contact surface of the end wall of the bobbin case.

In order to achieve as strong a magnetic field as possible, it is advantageous if the region of the end wall of the bobbin housing in which the controllable magnet of the gripping device contacts and the contact surface formed on the controllable magnet extend complementary to each other.

In order to facilitate the insertion of the bobbin case into the bracket of the corresponding receiving device, each bracket has at least two pins serving as positioning elements which are inserted into holes provided in the end wall of the bobbin case. These positioning elements serve on the one hand as an insertion aid when the bobbin case is inserted into the corresponding bracket to ensure the exact position of the bobbin case relative to the shuttle and on the other hand ensure this relative position during the rotation of the bobbin case to the shuttle.

In order to prevent the insertion of the bobbin case into the receptacle of the receptacle, in particular deflected by 180°, the bore and the positioning element have pairwise different cross-sections in their respective active ranges.

The structurally simple design of the carrier of the receiving device results in that it has at least one region of ferromagnetic material which cooperates with the permanent magnet in the receiving bobbin case.

When the bobbin case inserts a permanent magnet into its end wall in the area of the hollow cylinder, the basic simplification of the bobbin case can be achieved, wherein not only the later general stop bar, but also the hinged stop piece and the hinged stop bar can be omitted. Machining required later on its end walls.

This solution includes the additional advantage that the permanent magnet is able to cooperate within the receiving device with a ferromagnetic region of its corresponding holder and thereby retain the bobbin case in the holder.

When the retaining spring of a bobbin is arranged on the bobbin case, together with the cancellation of the blocking lever, it is also possible to completely cancel its hook-shaped end portion, which prevents the bobbin from being released from the shuttle when the bobbin case is taken out from the shuttle. Falling off in the housing, wherein the free end of retaining spring stretches between the two flanges of bobbin through the groove in the bobbin case side wall and keeps this free end of spring protruding beyond the side wall of bobbin case.

The end of the holding spring can be moved transversely to the longitudinal axis by means of a flange of the bobbin to simply insert the bobbin into the bobbin case.

Description of drawings

Additional advantages and details of the invention emerge from the following description of an exemplary embodiment thereof shown in the drawing. in:

Figure 1 is a sectional view of a shuttle, including the bobbin case together with a part of the receiving device and the grabbing device;

Figure 2 is a sectional view corresponding to Figure 1, including the bobbin case held by the grabbing device;

Figure 3 is a sectional view corresponding to Figure 1, comprising the bobbin case received by the bracket of the receiving means 21;

Figure 4 is a side view of the bracket of the receiving device;

Figure 5 is a sectional view of the bobbin case;

Figure 6 is a top view of the bobbin case according to Figure 5;

Fig. 7 is an arrow view of the grabbing device in the direction of arrow A in Fig. 2 .

Detailed ways

In FIG. 1, 1 marks the shuttle-side end of a horizontally arranged shuttle shaft which is installed in the base plate of a double lockstitch sewing machine not shown in more detail. The shuttle 2 connected to the shuttle shaft operates in a manner known per se with a guide (not shown) needle to form a seam.

In the shuttle 2, an inner casing 3 used to accommodate a bobbin case 4 is installed in a general manner, and the bobbin case itself carries a bobbin 5 for accommodating yarn stock. The inner housing 3 has a journal 6 for mounting the bobbin case 4, which is fastened to the bottom of the inner housing 3 in a manner known per se.

Although in the known inner housing construction its journal has a notch at its free end for the retaining rod of the bobbin case, in the journal 6 of the inner housing 3 of the present invention such a notch and Immediately thereafter the rounded top.

According to the invention, a magnetic retention of the bobbin case 4 is used in the position of the subsequent mechanical locking of the bobbin case with the journal of the inner housing. For this purpose a permanent magnet 8 is inserted into its end wall. In a preferred embodiment of the bobbin case 4 , the permanent magnet 8 is arranged and constructed in such a way that it runs flush with both the front outer wall 7 and its front inner wall 9 of the bobbin case 4 .

For this purpose, the journal 6 of the inner housing 3 is also shortened relative to the journal configuration of the common inner housing so that there is no air gap between the inner wall 9 of the bobbin case 4 and the end face of the journal 6 or only an air gap as small as possible is formed. Gap. The permanent magnet 8 can have a circular cross section whose diameter corresponds substantially to the diameter of the journal 6 . In order to achieve a particularly high holding force, the diameter of the permanent magnet 8 can be equal to or slightly larger than the diameter of the hollow cylinder 11 of the hub 10 on which the bobbin 5 is mounted.

The bobbin 5 is supported by the hollow cylinder 11 of the bobbin case 4 in a known manner. Owing to canceling the retainer lever of bobbin case 4 that is general later and thereby also canceling its hook-shaped end that prevents bobbin 5 on the hollow cylinder 11 from coming off when taking out bobbin case 4 from inner case 3 or shuttle 2 , The bobbin case 4 is provided with a retaining spring 12 . The retaining spring 12 is fastened at one end to the inner wall 9 and protrudes beyond the inner cavity of the bobbin case 4 through a groove 13 which is present after the bobbin case 4 is passed through the hook-shaped end of the catch bar. The retaining spring 12 has an elbow 14 comprising bifurcated flanges 15, 16, wherein the free end 17 of the flange 16 protrudes beyond the bobbin case 4 and can be used, for example, when removing an empty operating bobbin 5 manually at a changing station. As a handle to hold the spring 12. Since the elbow 14 protrudes only slightly into the inner chamber of the bobbin 5, when a bobbin 5 is inserted into the bobbin case 4, the elbow 14 and thus the retaining spring 12 are pressed outwards by the flange 18 of the bobbin 5. After the flange 18 has passed the elbow 14, the elbow 14 automatically returns to its position preventing the bobbin 5 in the bobbin case 4 from falling off.

The bobbin case 4 is unchanged in its cylindrical region 19 compared to known bobbin cases. A per se known clamping device for looping the thread is therefore arranged in this region in a known manner.

The changing station of the device according to the invention has a receiving device 21 for receiving the bobbin case 4 removed from the shuttle 2 and to be guided. The receiving device 21 is provided with brackets 22 arranged in a star. The bracket 22 is arranged on a shaft 23 positioned parallel to the shuttle shaft 1, and the shaft is rotated stepwise by a not shown drive device equipped with an indexing device, that is, one indexing angle at a time. .

The carrier 22 is made of a ferromagnetic material in the region where it receives the bobbin case 4 and each has two positioning elements 24 spaced apart from one another and diametrically opposite one another, which are designed as pins 25 , 26 in the exemplary embodiment shown. . The pins 25 , 26 are likewise positioned parallel to the shuttle shaft 1 and have different cross-sections in the region where they cooperate with the bobbin case 4 . The pins 25 , 26 can be slightly conical in this region.

For the cooperation of the positioning element 24 with the corresponding bobbin case 4, two holes 27, 28 are provided in the end wall of the bobbin case 4, the cross-sections of which are likewise different. The holes 27, 28 and the pins 25, 26 in the end wall 7 of the bobbin case 4 are arranged in such a way that when the bobbin case 4 is received on the pins 25, 26, its position relative to the shuttle 2 corresponds to the position of the bobbin case 4 in the shuttle. 2, wherein the limiting surfaces 29, 31 of the hole 32 provided in a common way on the bobbin case 4 contact the positioning pins provided in a common way in the inner casing 3.

Since the pins 25, 26 and the holes 27, 28 have a pair of different cross-sections, on the one hand, when inserting the bobbin case 4 into the bracket 22, it is prevented from being inserted in the opposite direction and on the other hand, during its removal from the shuttle 2. In, especially in the process that bobbin case 4 is introduced into shuttle 2, bobbin case 4 can be prevented from deflecting.

In order to remove the bobbin case 4 from the shuttle 2 and transfer it to the bracket 22 of the receiving device 21 or from the receiving device to the shuttle 2, a gripping device 33 is provided, which has a holding element 34, which 34 includes two steerable magnets 35 . The two magnets 35 cooperate with the end wall 7 of the bobbin case 4, wherein their contact surfaces 36 and the contact surfaces of the end wall 7 of the bobbin case 4 extend complementary to each other. The mutual spacing of the two magnets 35 and the width of the carriage 22 are determined in such a way that (see FIG. 4 ) one magnet 35 is moved over one side of the carriage 22 in the operating position and the other magnet 35 is moved over its other side. The two magnets 35 are connected to the same power source and switched together. The force applied to the bobbin case 4 by the two magnets 35 is greater than the force applied to the bobbin case 4 by the permanent magnet 8 .

Both magnets 35 are provided with a common slide 38 which is displaceable along a guide rail 39 positioned parallel to the shuttle shaft 1 . Wherein the arrangement of the guide rail 39 constitutes that the two magnets 35 can symmetrically contact the end wall 7 of the bobbin case 4 .

The carriage 38 is assigned a drive, which is supported by a fixedly mounted frame 41 and which can be designed as a cylinder or as a magnet 42 . It moves the carriage 38 along the guide rail 39 from the changing station to the shuttle 2 or from the shuttle 2 to the changing station. For this, the cylinder/magnet 42 is connected to the carriage 38 via a toggle lever 43 mounted on the frame 41 and a pin/long hole connection point and moves the carriage against the force of the spring 44 towards the shuttle 2 and thereby move toward the bobbin case 4.

In order to remove the bobbin case 4 from the shuttle 2 , the gripping device 33 is moved from its rest position in the region of the carriage 22 along the guide rail 39 in the direction of the shuttle 2 . The magnets 35 are energized as soon as the contact surfaces 36 of the magnets 35 are in contact with the contact surfaces 37 of the end wall 7 of the bobbin case 4 . The force applied to the bobbin case 4 by it is greater than the force from the permanent magnet 8, so that the bobbin case 4 together with the bobbin 5, which is prevented from falling off by the retaining spring 12, is guided out of the pendulum during the subsequent return movement of the slide seat. Shuttle 2 and guide carriage 22. At the end of this movement the positioning elements 24 (pins 25 , 26 ) engage in holes 27 , 28 of the bobbin case 4 , so that the carrier 22 receives the bobbin case 4 in a precisely predetermined position relative to the carrier 22 . After the magnet 35 has been disconnected, the bobbin case 4 is held on the carriage 22 by means of the permanent magnet 8 and can then be removed from the carriage 22 either manually or by means of a removal device against the force of the permanent magnet 8 .

Intermittently or subsequently, a bobbin case 4 provided with a filled bobbin 5 can be inserted onto the carrier 22 either manually or by means of a feeding device. Since the pins 25 , 26 and the holes 27 , 28 have pairwise different cross-sections, the position of the bobbin case 4 relative to the bracket 22 is predetermined and reverse insertion of the bobbin case 4 is thus excluded. Because the relative position of the bobbin case 4 to the carriage 22 conforms to the relative position between the bobbin case 4 and the shuttle 2 or the inner case 3, the bobbin case 4 must be positioned on the carriage 22 accurately. As soon as the bobbin case 4 approaches the ferromagnetic region corresponding to the carrier 22 in this relative position, the bobbin case 4 is held on the carrier 22 by the permanent magnet 8 .

Before the now subsequent movement of the carriage 38 , the magnets 35 of the holding element 34 are energized. Once the contact surfaces 36 of the magnets 35 are pressed against the end wall 7 of the new bobbin case 4 and its force exceeds the force of the permanent magnet 8, the new bobbin case 4 breaks away from the bracket 22 and moves further with its opposite direction in the gripping device 33. The exact relative position of the shuttle 2 is pushed into the shuttle 2.

After the bobbin case 4 has reached its end position in the shuttle 2, the inner wall 9 of the bobbin case 4 rests against the end face of the journal 6 of the inner case 3, so that the bobbin case 4 is clamped by the permanent magnet after the magnet 35 has been disconnected. In Shuttle 2. The gripping device 33 and its magnet 35 can be returned to their starting position in the direction away from the shuttle 2 by unloading the spring 44 of the drive.

In order to achieve a precisely positioned position of the carriage 22 , in particular when it is fed, two rods 45 spaced apart from one another and positioned parallel to the axis of the shuttle 2 are provided on the gripping device 33 . In the region of its front and rear ends, each rod 45 is provided with a slide 46 which extends at its end in a funnel-shaped expansion. The spacing of the skids 46 constituting the positioning device 47 of the carriage 22 corresponds to the corresponding width of the carriage 22, so that each carriage 22 in the operating position not only moves the gripping device 33 from the receiving device 21 to the shuttle 2 but also During its movement from shuttle 2 to receptacle 21 , its exact position is maintained by means of slides 46 .

Claims (11)

1. be used to change the device of the bobbin case that is loaded with shuttle on double-lock type stitch sewing or embroidery machine, bobbin case is by an axle journal supporting that is provided with in shuttle, and this device comprises a holding device, and this holding device has the carriage that comprises a plurality of receiving positions that is used for bobbin case; And comprise that one has the grabbing device that at least one is used for the holding element of bobbin case, for the replacing position that bobbin case is forwarded to shuttle and forwards holding device from shuttle to from the replacing position of holding device, holding element can move along a guide rail that is arranged essentially parallel to the shuttle extension, it is characterized in that, holding element (34) has the controllable magnet (35) of the end-face wall (7) of at least one contact bobbin case (4), and each bobbin case (4) respectively have in the zone of its end-face wall (7) one as locking member and with the crew-served permanent magnet of axle journal (6) (8), it affacts confining force on the axle journal (6) less than the power of controllable magnet (35).

2. according to the described device of claim 1, it is characterized in that holding element (34) has two controllable magnet (35), described magnet is contact with it on the contact-making surface (37) of the mutual diametrically contraposition of the end-face wall (7) of bobbin case (4).

3. according to claim 1 or 2 described devices, it is characterized in that contact-making surface (37) on the bobbin case (4) and controllable magnet (35) are gone up the contact-making surface (36) that constitutes and complementally extended to each other.

4. according to one of aforesaid right requirement item or multinomial described device, it is characterized in that, the carriage (22) of holding device (21) has two or more pins (25,26) as setting element (24), and these pins are embedded in the hole (27,28) that is provided with in the end-face wall (7) of bobbin case (4).

5. according to one of aforesaid right requirement item or multinomial described device, it is characterized in that hole (27,28) have different cross section in pairs with setting element (24) in its corresponding active region.

6. one of require or multinomial described device according to aforesaid right, it is characterized in that carriage (22) has the zone that at least one is made of ferrimagnet, this zone in by the bobbin case (4) of its admittance with its permanent magnet (8) co-operating.

7. according to one of aforesaid right requirement item or multinomial described device, it is characterized in that grabbing device (33) has the setting element (47) that is used for carriage (22).

8. according to the described device of claim 7, it is characterized in that, setting element (47) is made of the sled (46) that some are arranged essentially parallel to the axis location of shuttle (2), and its mutual spacing is equivalent to width and its both ends funneling expansion of carriage (22) and extends.

9. be used for changing the shuttle that device adopted of the bobbin case that is loaded with shuttle on double-lock type stitch sewing or embroidery machine, wherein bobbin case is by an axle journal supporting that is provided with on the bottom surface of inner casing and have a hollow cylinder that is used to support shuttle; It is characterized in that, a permanent magnet (8) that inserts in the zone of hollow cylinder (11) in bobbin case (4) end-face wall (7), this magnet are when bobbin case (4) inserts in the shuttle (2) and its axle journal (6) co-operating and when bobbin case (4) is admitted by one of carriage of holding device (21) (22) and a ferromagnetic region co-operating of carriage (22).

10. according to the described shuttle of claim 9, it is characterized in that, one is fixed on the maintenance spring (12) that is used for shuttle (5) on the end face inwall (9) of bobbin case (4), its free end has an elbow (14), this elbow (14) extend between two flanges (18) of shuttle (5) by the groove (13) in the bobbin case (4), and its free end (17) protrudes beyond the sidewall of bobbin case (4).

11., it is characterized in that the end of the maintenance spring (12) of bobbin case (4) can be moved transverse to its longitudinal axis by a flange (18) of shuttle (5) according to one of aforesaid right requirement item or multinomial described device.

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