CN109563664B

CN109563664B - Sewing machine with bobbin case replacing device

Info

Publication number: CN109563664B
Application number: CN201780032380.9A
Authority: CN
Inventors: K-L·曼纽尔
Original assignee: Pfaff Industriesysteme und Maschinen GmbH
Current assignee: Pfaff Industriesysteme und Maschinen GmbH
Priority date: 2016-04-30
Filing date: 2017-04-30
Publication date: 2023-02-28
Anticipated expiration: 2037-04-30
Also published as: WO2017186353A1; EP3449052A1; JP2019515743A; CN109563664A; DE102016005166A1; EP3449052B1

Abstract

In order to improve the operational safety of a sewing machine with a bobbin case changing device in which a bobbin case (4) with a bobbin for guiding an upper thread can be accommodated and a bobbin case changing device (8) with which one bobbin case (4) can be removed from a magazine (9) and this bobbin case (4) can be inserted into the rotary hook (5) in a sewing machine for needle return, the bobbin case changing device (8) is fixed to an upper frame part (2) of the sewing machine, the invention proposes that the bobbin case changing device be fixed to the rotary hook (5).

Description

Sewing machine with bobbin case replacing device

Technical Field

The invention relates to a sewing machine for sewing a loop stitch, which is provided with a needle bar for receiving a needle for guiding an upper thread, and with a rotary hook in which a bobbin housing having a bobbin for guiding a lower thread can be received, and with a bobbin housing changing device by means of which one bobbin housing can be removed from a bobbin housing magazine (also referred to as magazine, rotary magazine) in which a large number of bobbin housings can be arranged and can be inserted into the rotary hook.

Background

The sewing machine forms a seam in a manner using a needle that guides a reciprocating oscillating motion of an upper thread. In a double back needle sewing machine, a needle guides an upper thread, and the upper thread is interwoven with a preliminary yarn for a lower thread disposed on a bobbin into a double back needle. The bobbin is in a rotating hook which performs a rotating movement relative to the bobbin and in each stitch the needle hooks the upper thread in the sewing and interweaves it with the lower thread.

The bobbin is usually in a bobbin case, inserted into a rotary hook of a double back needle sewing machine together with the bobbin, and after the bobbin is evacuated, it is taken out together with its bobbin case and replaced with a full bobbin. Such a changing process of changing an empty bobbin with a full bobbin has to be carried out relatively frequently, since the usual bobbin has only a small yarn receiving capacity. Therefore, a bobbin case exchanging apparatus is known which can automatically exchange a bobbin case having a vacant bobbin in a rotary hook with a full bobbin case. The bobbin case in which the bobbin filled with the yarn is arranged may be arranged in the bobbin case magazine.

DE 10 2010 003 182 B4 discloses a cartridge of this type, for example. An endless warp conveyor is disclosed on which a number of receptacles for the bobbin case are arranged along the warp yarns. The exchange process and the removal of the bobbin case from the warp thread conveyor are carried out by a push-pull process carried out by means of a lever. However, in such replacement devices, the operational safety may not be satisfactory.

Disclosure of Invention

In view of the above, it is an object of the present invention to improve the operational safety of a sewing machine having a bobbin case changing device of the type described in the opening paragraph.

To achieve the above object, according to the invention, in a sewing machine of the type mentioned in the opening paragraph, the bobbin case changing device is fixed to an upper part of a frame of the sewing machine. Since in the previously known bobbin case changing devices the components and/or the rotary hook thereof are fixed to different carrier parts of the sewing machine, it is possible in the prior art to impair the operational safety of the bobbin case changing device due to the very small relative movements and variations in orientation between the sewing machine frame and the fixing point of the bobbin case changing device. Temperature changes may cause such damage. According to the invention, the bobbin case changing tool, i.e. in particular the gripper element thereof, is arranged on the upper frame part of the sewing machine, on which frame part a rotary hook with a holder is likewise fastened. This ensures that, for example, thermally related expansion or contraction of the frame acts in the same way on all components of the changing tool and the rotary hook, so that the distance between the above-mentioned components is not changed or is changed at most to a lesser extent. Thus, in the case of a rotary hook, operational safety can be ensured without readjustment of the orientation of the bobbin case changing device. The solution of the present invention to achieve the above object is also the bobbin case exchanging device described in the embodiments.

In a preferred embodiment of the invention, which can have independent significance, the bobbin case changing device can have deflectable gripper members, by means of which one bobbin case can be transferred from the bobbin case magazine to the hook of the sewing machine and inserted. With this solution, on the one hand, a very fast movement between the bobbin case magazine and the rotary hook can be implemented, which contributes to a reduction in the unproductive time for bobbin change. On the other hand, this solution makes the bobbin case changing device of the present invention particularly compact. The compact bobbin case changing device achieved by the present invention is also suitable for retrofitting sewing machines which hitherto have no bobbin case changing device or only a less than satisfactory bobbin case changing device.

A further preferred embodiment of the invention, which can likewise have an independent meaning, is to provide the bobbin case changing device with a bobbin case magazine which is rotatable about a rotational axis and which has several receptacles, preferably more than two receptacles, each for one bobbin case, distributed about the rotational axis. This preferred measure of the invention likewise facilitates a particularly compact design of the bobbin case changing device according to the invention and also facilitates the changing process to be carried out in a particularly rapid and safe manner.

Other preferred embodiments of the invention are described in the claims, the description and the drawings.

Drawings

The invention will be elucidated in detail on the basis of an embodiment which is shown purely schematically in the drawing, in which:

FIG. 1 is a partial perspective view of a needle return sewing machine below a bed in the area of a rotating hook and bobbin case changer of the present invention, with the bed and upper portion of the sewing machine deflected to a service position; the bobbin case replacing device is in a standby position;

fig. 2 is the view according to fig. 1 with the bobbin case changing device in the removal position for removing the bobbin case from the bobbin case magazine;

fig. 3 is another view according to fig. 2 with the bobbin case changing device in the removal position for removing the bobbin case from the bobbin case magazine;

fig. 4 is a view according to fig. 1, wherein the gripping member of the bobbin case changing device takes out the bobbin case from the bobbin case magazine;

fig. 5 is a view according to fig. 1, wherein the gripping member of the bobbin case changing device is in a transfer position with respect to the rotary hook;

fig. 6 is a view according to fig. 1, wherein the gripping member of the bobbin case changing device transfers the bobbin case to the rotary hook;

fig. 7 is a view according to fig. 1, wherein the gripping member of the bobbin case changing device releases the bobbin case in the rotary hook;

fig. 8 is a view according to fig. 1, wherein the gripping member of the bobbin case changing device is again in a standby position after transfer of the bobbin case to the rotary hook;

FIG. 9 is a cross-sectional view of the handling hook of the gripping member of FIG. 1;

FIG. 10 is a cross-sectional view of the carrier of FIG. 9 with the flip cover of the bobbin case deflected and gripped by the carrier;

Detailed Description

Fig. 1 shows an example of a sewing machine 1 embodied as a double-looper sewing machine in a single detail, the housing 2 of which has a lower, so-called bed plate, from which the stands 3 extend substantially vertically upwards. The upper extremity of the stand is connected to an arm generally parallel to the base plate.

The sewing machine has an arm shaft supported in an arm, which is likewise not shown in fig. 1 or is optionally only partially or greatly simplified, as other essential components of the sewing machine described below. The arm shaft drives a needle bar that can be oscillated back and forth, and can fix a needle for accommodating an upper thread (not shown) on a needle holder of the needle bar. On the base plate, a hook device 3 with a rotary hook is arranged, the rotary movement of which is synchronized with the oscillating movement of the needle bar. The lower thread is on a bobbin which is arranged in a multipart bobbin case. The hook device 3 guides the needle-guided upper thread around the bobbin case 4 with its rotary hook in a known manner, so that this upper thread can form a seam together with the lower thread. The needle bar and the hook device are usually driven by the same drive, i.e. a servomotor, not shown in detail, and the machine spindle takes the drive movement of the servomotor relative to the needle bar and relative to the hook device 3 and converts it into a certain ratio. In other embodiments of the invention, however, it is also possible to provide sewing machines which employ constructive solutions deviating from the above-described solution, for example by not driving the needle bar and the rotary hook with the same main shaft.

Furthermore, the sewing machine has a feed device, not shown in detail, which comprises a needle transport device and/or a top transport device. The material slide for the needle threading, which is also driven by the machine spindle via a corresponding transmission, is therefore provided with a needle hole.

Fig. 1 to 8 show the components of the hook device 3 arranged in the base plate, which components are located directly below the needle plate in the base plate. The hook device 3 has a wraparound rotary hook 3 in a vertical plane, adapted to house, in a known manner, a bobbin containing a preliminary yarn, together with its bobbin case. Fig. 1 shows a rotary hook without a bobbin and a bobbin case. Whereas in fig. 8, the bobbin with the preliminary lower thread is arranged in the rotary hook 5. For this purpose, the bobbin 11 is in the bobbin case 4 and can be inserted into the rotary hook 5 and removed from the rotary hook 5 in such a way that it is arranged in the bobbin case.

Fig. 1 to 8 also show a preferred embodiment of the bobbin case changing device 8 of the present invention. This bobbin case changing device has a bobbin case magazine constructed as a bobbin case magazine 9 for arranging a plurality of bobbin cases 4. The disk-shaped bobbin case 9 can be rotated about a rotational axis, wherein a drive movement for the rotational movement is generated by means of an electric motor 10. The electric motor 10 provided for this purpose is located behind the bobbin case 9, with the rotational axis of the electric motor 10 being aligned with the rotational axis of the bobbin case 9. On the top side of the disk-shaped bobbin case 9, along an imaginary circumference extending concentrically around the axis of rotation, a socket 12 is provided. A bobbin case 4 may be disposed on each of these insertion openings. The plurality of pin-shaped sockets 12 are evenly distributed along an imaginary circumference. In the embodiment shown, the bobbin case magazine 9 has a total of 9 receptacles. The insertion opening 12 is matched to the bobbin case 4 in such a way that, in the case of a pin-shaped insertion opening 12, the bobbin case can be arranged only in a specific rotational position and locked against rotational movement on the insertion opening 12.

Finally, the bobbin case changer 8 also has a first sensor 14 arranged in the region of the bobbin case magazine, by means of which the bobbin case can be brought into a predetermined transfer or change position. The transfer or replacement position is always the same rotational position in which the transport shuttles of the bobbin case replacement device 8 each receive one bobbin case 4 and remove it from the bobbin case magazine 9. It can be determined by means of a second sensor 15 arranged in the area of the transfer or replacement position whether the bobbin case 4 is still arranged in the receptacle 12 in the transfer or replacement position. The signals of the

sensors

14, 15 can be used by a control device of the sewing machine and the electric motor 10 can be controlled by the control device in accordance with these signals. Depending on the signals of the

sensors

14, 15, the bobbin case magazine is stopped in particular when the bobbin case reaches the transfer position.

Furthermore, the bobbin case changer 8 is assigned a deflection arm 18, which is mounted on one of its ends so as to be deflectable about a deflection axis 18 a. In order to perform a pivoting movement in each of the two pivoting directions, the pivoting arm 18a is operatively connected to a motor 19, in particular an electric motor. The motor 19 of the deflecting arm 18 is also controlled by the control device of the sewing machine.

The deflecting arm 18 with its motor drive and the bobbin case 9 with its motor drive are jointly fixed on and held by a supporting part 24. The support part 24 is in turn fixed to the housing 2 of the sewing machine below the bed plate of the sewing machine, i.e. to the upper part of the sewing machine. As can be seen from the embodiment of fig. 1-8, the support element is fixed to the upper part of the sewing machine by means of several screws. On the same housing part of the sewing machine, here on the upper part of the sewing machine, a hook device with a rotary hook 5 is likewise fixed and arranged. In the views of fig. 1-8, the upper portion of the sewing machine is open and is thus disposed in a service position.

The deflecting arm 18 is provided at its free end with a handling hook 20 for the bobbin case. The handling shuttle 20 is arranged on a support 21, which in turn is fixed to the deflecting arm 18. The carriage 21 is linearly movable relative to the deflecting arm 18 in a direction parallel to the deflecting axis 18 a. By this movement, the handling hook 20 can be moved in the direction of the bobbin case magazine 9 and can be pulled back again with it being arranged in front of the bobbin case magazine 9 by the deflecting arm 18. The transport hook 20 can also be placed in front of the rotary hook 5 of the sewing machine, with the transport hook placed in front of the rotary hook 5 by means of the deflecting arm.

By means of the handling of the hook 20 and the feed movement to the bobbin case magazine 9, the bobbin case 4 with the bobbin arranged therein can be removed from the bobbin case magazine 9 and transferred to the rotary hook 5 by means of the deflecting movement of the deflecting arm 18 and the feed movement to the rotary hook 5. The carrier loop 20 shown in detail in figures 9 and 10 has a loop socket 22 for arranging the bobbin case 4 on the rotary loop 5, the geometry of which matches that of the loop 4. The handling hook 20 has a mating surface which corresponds to the outer shape of the outer surface region of the bobbin case, in particular in the transition region of the bobbin case for enclosing the closed end side of the bobbin case 4. The insertion opening 22 has a parabolic counter surface 23 against which a section of the peripheral region of the closed end side of the bobbin case 4 can be at least substantially form-fittingly placed. The bobbin case 4 in the carrying hook is thus unambiguously positioned in a total of three spatial directions, with respect to the longitudinal axis of the bobbin case 4, until its rotational position is reached.

Furthermore, the transport hook 20 has a bobbin case holding hand 25 with an inclined contact surface 26 in terms of the orientation of the longitudinal axis of the bobbin case 4 in the transport hook 20 and with a free end 27 which tapers off. Bobbin case retaining finger 25 may be pushed against bobbin insertion opening 22 and transversely to the longitudinal axis of bobbin case 4. This movement is carried out in a driven manner and is determined by the control device. In this movement, the tip of the free end 27 of the bobbin case retaining finger 25 reaches between the bobbin case flap 28 and the top side of the closed end side of the bobbin case 4, based on the unambiguous only possible rotational orientation of the bobbin case 4 in the transport hook 20. Subsequently, in a further linear movement of the bobbin case retaining finger 25, the bobbin case flap 28, which is pivotably articulated on the bobbin case 4, is pivoted towards the counter-slope 29 of the hook insertion opening 22. The bobbin case flap 28 is thereby pressed along the major part of its longitudinal extension into the groove 30 of the counter-ramp 19. The bobbin case retaining finger 25 rests against the bobbin case flap 28 on the side of the bobbin case flap 28 facing away from the groove 30 and retains the bobbin case flap 28 in the groove. The width of the slot 30 corresponds approximately to the width of the bobbin case flap 28. The bobbin case flap 28 is thus held in this case in the groove 30 and in the carrying hook 20 in a form-fitting, in particular passive form-fitting manner. Furthermore, the bobbin case 4 is thus clearly positioned in the transport hook 20 in its spatial position as well as in its rotational position.

Further, the carrier hook 20 can release the bobbin case lid 28 and the bobbin case 4 as a whole again by pulling back the bobbin case retaining pointer 25. This can be used to insert and locate the bobbin case 4 in the rotary hook 5 or, if necessary, in the receptacle of the bobbin case magazine 9.

Furthermore, the sewing machine is equipped with a known sensor 32 for identifying the remaining yarn, i.e. a sensor which can be used to determine whether or when the lower thread bobbin has reached a certain degree of emptying so that there is still a certain amount of remaining yarn on the bobbin. The sensor 32 for identifying the remaining yarn on the bobbin transmits a signal representing this detection result to the sewing machine control which then performs bobbin replacement based on identifying the amount of remaining yarn as the remaining preparatory yarn, but at least informs the operator that bobbin replacement is required. In the case of automatic exchange of the bobbin or bobbin case 4, the control device should not interrupt the seam being sewn at the time of manufacture up to the amount of yarn remaining. Therefore, the sewing machine sewed at that time can not become waste.

The control device initiates a replacement to replace the near-empty bobbin with a full bobbin in the rotary hook. For this purpose, the last sewing process must first be ended and the needle must be arranged outside the rotary hook 5. The deflecting arm 18 is then first deflected from its standby position shown in fig. 1 to a first deflected position in front of the rotary hook. If at this point in time the bobbin case 4 has been arranged in the carrying hook 20, the carrying hook 20 is in a position in which the longitudinal axis of the bobbin case 4 is aligned in the rotary hook 5 with the course of the longitudinal axis of the bobbin case in the carrying hook 20.

The carriage 21 is thus moved towards the bobbin case along the longitudinal axis of the bobbin case 4 or parallel to the longitudinal axis of the bobbin case with the position of the deflecting arm 18 unchanged, so that the receptacle for carrying the hook 20 is directly above the bobbin case 4. As shown in fig. 9 and 10, the bobbin case holding finger 25 is moved toward the bobbin case lid 28 and presses this bobbin case lid into the slot 30 toward the bobbin case mating face 29. Thus, the bobbin case 4 is held in the carrier hook 20. This enables the bobbin case 4 with the nearly spent bobbin to be removed from the rotary hook 5 by movement of the bracket 21 back to the deflecting arm 18.

Subsequently, the deflecting arm 18 is moved in the direction of the cartridge 9. In the appropriate position, the bobbin case retaining finger 25 is pulled back before reaching the final position in front of the bobbin case magazine 9, i.e. between the final position of the deflecting arm 18 of the rotary hook 5 and the other final position in front of the bobbin case magazine 9. The spring-loaded bobbin case flap 28 is thereby released and is thereby deflected to the closed end side of the bobbin case 4 and rests against this end side. The near-empty bobbin case 4 can be dropped from the carrying hook 20 in a predetermined manner. The bobbin case holding pointer 25 is preferably pulled back at a position where the carrier hook 20 is above the container to which the bobbin case 4 with the nearly spent bobbin can be dropped.

The deflecting movement of the deflecting arm 18 is stopped in the case where the deflecting arm 18 reaches its second final position opposite the bobbin case 9 (fig. 1). In this final position, the handling hook 20 is arranged opposite the exchange position of the bobbin case magazine 9, in which the bobbin case magazine rotates one of the respective insertion openings 12, so that the bobbin case 4 arranged in this insertion opening 12 is removed together with its bobbin filled with the lower thread by the handling hook 20. By means of the second sensor 15, it is determined whether any further bobbin case 4 is in the respective receptacle. It is determined by means of the first sensor 14 whether the corresponding bobbin case 4 is in the predetermined exchange position.

In this case, the handling hook 20 is also arranged by means of the deflecting arm 18 in such a way that, after the handling hook 20 has been brought into its second deflected position, it is then merely necessary to guide the hook by means of a parallel displacement of the carrier 21 relative to the deflecting arm 18 to the bobbin case arranged in the replacement position of the bobbin case magazine 9 in order to arrange the bobbin case in the insertion opening 22 of the handling hook 20 (fig. 2). After the carrier hook 20 has been brought into the change position in this way (fig. 3), the bobbin case flap 28 is mounted by means of the bobbin case retaining finger 25 in the manner already described on the counter ramp 29 of the insertion opening 22 and is inserted into the groove 30 arranged in the ramp, so that the bobbin case 4 on the carrier hook 20 remains in the predetermined orientation and is detected (fig. 10). Subsequently, the support 21 can be pulled back again (fig. 4) and the deflecting arm 18 can be positioned in its first final position (fig. 5) in front of the rotary hook 5. Subsequently, the handling hook 20 with the bobbin case 4 inserted therein is transported towards the rotary hook 5 by means of the translational movement of the carriage 21 and inserted into this rotary hook (fig. 6). The bobbin case 4 is separated from the carrier hook 20 and secured in the rotary hook 5 by pulling back the bobbin case retaining finger 25 and deflecting the bobbin case flap 28 back (fig. 7). The standardized bobbin case 4 is fixed in the rotary hook 5 in a known manner, the bobbin case 4 also being fixed in the receptacle 12 of the bobbin case 9 in a manner which is in principle the same.

After the support 21 has been moved back in the direction of the deflecting arm 18, the deflecting arm 18 can be deflected again into its standby position and arranged in this standby position until it is necessary to replace the bobbin case 4 currently arranged in the rotary hook 5 with a new bobbin case 4 in the bobbin case magazine 9 (fig. 8).

List of reference numerals

1. Sewing machine

2. Shell body

3. Shuttle device

4. Bobbin case

5. Rotary shuttle

6

7

8. Bobbin case replacing device

9. Bobbin case box

10. Electric motor

11. Shuttle peg

12. Socket

13

14. First sensor

15. Second sensor

16

18. Deflection arm

18a deflection axis

19. Electric motor

20. Shuttle carrier

21. Support frame

22. Shuttle socket

23. Parabolic mating surface

24. Bearing part

25. Bobbin case holding pointer

26. Contact surface

27. Free end

28. Bobbin case flip

29. Paired inclined planes

30. Trough

31

32. Residual yarn sensor

33

Claims

1. A sewing machine for sewing a backstitch is provided with a needle bar for receiving a needle guiding an upper thread, with a rotary hook (5) in which a bobbin housing (4) with a bobbin guiding a lower thread can be received, and with a bobbin housing changing device (8) with the aid of whose gripping means the bobbin housing (4) can be removed from a bobbin housing (9) and this bobbin housing (4) can be inserted into the rotary hook (5),

it is characterized in that the preparation method is characterized in that,

the bobbin case changing device (8) is fixed to the same housing part as the rotary hook (5), in particular to the housing (2) of the sewing machine, wherein the rotary hook (5) and its support are fixed to the base plate of the housing (2).

2. Sewing machine as in claim 1, characterized in that said bobbin case changing device (8) has a deflectable gripping member by means of which the bobbin case (4) can be transferred from the bobbin case magazine (9) to the rotary hook of the sewing machine and inserted in a manner applying a deflecting movement of the gripping member.

3. Sewing machine as in claim 2, characterized in that the deflectable gripping member has a deflection arm (18) deflectable about a deflection axis, on the end of which, arranged at a distance from the deflection axis, a handling hook (20) for receiving and transferring the bobbin case is provided.

4. Sewing machine as in claim 3, characterized in that it has a support (21) arranged on said deflecting arm (18), on which support said handling hook (20) for the bobbin case is located, wherein said support (21) is movable with respect to said deflecting arm.

5. Sewing machine as in claim 3, characterized in that said carriage is movable in a rectilinear motion along an axis of motion parallel to the deflection axis (18 a) of said deflection arm (18).

6. Sewing machine as in any one of claims 2 to 5, characterized in that the gripping element is provided with a receptacle (22) for the bobbin case (4), by means of whose bobbin case retaining pointer (25) the bobbin case (4) can be arranged in a rotationally fixed manner in the receptacle (22) by clamping a deflectable bobbin case flap (28), wherein the bobbin case retaining pointer (25) is in a groove (30) of the face of the receptacle (22), which groove (30) extends obliquely to the longitudinal axis of the bobbin case (4).

7. Sewing machine as in any claim from 2 to 5, characterized in that said bobbin case changing device (8) has a bobbin case magazine (9) rotatable about a rotation axis, said bobbin case magazine having several receptacles for the bobbin cases distributed about said rotation axis.

8. Sewing machine as in claim 7, characterized in that the axis of rotation of said cartridge (9) is at least substantially parallel to the axis of rotation of said rotary hook (5).

9. Sewing machine as claimed in any of the claims 2-5, characterized in that the deflecting axis of the gripping member is at least substantially parallel to the axis of rotation of the cartridge.

10. Sewing machine according to any one of claims 2-5, characterized in that it has a support part (24) on which the gripping member together with its motor drive and the bobbin case (9) together with its motor drive are arranged together, wherein the support part (24) is in turn detachably fixed on the housing (2) of the sewing machine below the bed plate.