EP2176156B1 - Device for cutting a thread-shaped body - Google Patents

Abstract

The device (1) is used to cut a longitudinally moving thread-shaped body (9). It comprises a cutting blade (5) and an anvil (6) interacting with the cutting blade (5). A solenoid actuator for the cutting blade (5) comprises a plunger coil (3), a two-piece magnet return path yoke (21, 22), and a solenoid plunger (4) connected to the cutting blade (5). A supporting structure (7) carries the plunger coil (3) and the two half-yokes (21, 22). The half-yokes (21, 22) are attached by elastically deflectable arms (81, 82) by means of engaging closures (71-74) on the supporting structure (7). The device (1) therefore has a simple design and is easy and cost-effective to produce.

Description

AREA OF EXPERTISE

The present invention is in the field of severing filamentary material. It relates to a device for cutting a thread-like, preferably longitudinally moving body according to the preamble of the first claim. Their preferred use is in yarn cleaners, as are common for monitoring and guaranteeing yarn quality on spinning or winding machines.

STATE OF THE ART

Devices for automatically detecting and cutting out defective yarn sections from a longitudinally moved yarn are referred to in the textile industry as yarn cleaners. They are attached in large numbers to spinning and winding machines for yarns at each spinning or winding unit. Also for cutting other elongate textile structures such as rovings, ribbons, etc. cutting devices are needed.

From the WO-00/06479 A1 For example, a generic cutting device is known in which, as in previously known devices of this type, a perpendicular to the longitudinal direction of the longitudinally moved filamentary body movable back and forth cutting blade is provided which cooperates with a fixed counter-attitude. To cut the longitudinally moving thread-like body, the cutting blade is moved towards the counter-holding until it bounces on the counter-holding. This causes a cut in the body. Then the cutting knife is moved back to its original position, where it remains until a new cut is due.

FIG. 1 shows a perspective view of a cutting device 1 ', as known from the prior art, such as WO-00/06479 A1 , is known. The cutting device 1 'includes a carrier 10'. A yoke 2 ', a cylindrical plunger 3' and a cylindrical, along its longitudinal axis movable plunger armature 4 'form a drive for a knife holder 51' and thus also for a cutting blade 5 '. An opposing or anvil 6 'is in the embodiment of FIG. 1 formed as a part of the carrier 1 '. The anvil 6 'has a hardened surface 60', in front of which a longitudinally moved thread-like body 9, such as here for example a yarn, is moved in the direction of an arrow 90. On the carrier 1 'can be seen parts of two screw 11' and 12 ', via which the device 1' can be attached, for example, on a textile machine such as a spinning or winding machine. The cutting blade 5 'is preferably fixedly connected to the knife holder 51', which in turn here via a releasable positive connection 52 'with a plunger 43' ( FIG. 2 ), which forms an extension of the plunger anchor 4 ', is connected. It is known per se, and therefore not shown here in detail, that the plunger coil 3 'has turns, which are connected via lines to a control circuit, not shown in this figure, via which the plunger 3' is driven to the cutting blade 5 'to actuate.

In FIG. 2 are essential parts of the cutting device 1 'of FIG. 1 shown. The view is different than in FIG. 1 : While in FIG. 1 a view from the left is shown FIG. 2 a view from the right behind. Furthermore, the view is from FIG. 2 partially disclosed; In particular, the plunger coil 3 'is not shown, so that a view is given in the space enclosed by the plunger coil 3' interior. A front end 41 'of the plunger armature 4' is conical and can be received by a correspondingly complementary, cylindrical, aligned along a longitudinal axis receiving piece 21 'of the return yoke 2'. The plunger armature 4 'continues in a plunger 43', which protrudes from the yoke 2 'and the blade holder 51' and the cutting blade 5 '(in FIG. 2 for the sake of simplicity are not shown) carries. The plunger 43 'has a purely mechanical function; it must not be made of a ferromagnetic material so as not to disturb the magnetic operation of the system described below. It can also be seen a part of a return spring 49 ', which is stretched during the cutting movement and after the cutting operation, the plunger armature 4' back into the in FIG. 2 shown starting position presses.

To a longitudinally moved filamentary body 9 ( FIG. 1 ), ie cut such that defective parts are removed therefrom, a cut is produced for which the cutting blade 5 'is moved as fast as possible and with sufficient force or high kinetic energy towards the counterstay or the anvil 6'. The thread-like body 9 is thereby clamped between the cutting blade 5 'and anvil 6' on the surface 60 'and cut by the cutting blade 5'. The drive of the cutting device is based on the principle of magnetic reluctance. The plunger armature 4 'and the yoke 2' each consist of a ferromagnetic material. Together they form a ferromagnetic core, which is partially enclosed by the plunger coil 3. In the initial position there is a gap 44 'between the front end 41' of the plunger armature 4 'and the rear end of the receiving piece 21'. To trigger the cutting process, the plunger coil 3 is energized, whereby in each of the two U-shaped bracket of the yoke 2 'a closed magnetic field is generated. The magnetic field energy of the system is the smaller the smaller the gap 44 'is. The system tends to minimize its magnetic field energy and thus reduce the gap 44 ', so that the plunger armature 4' is accelerated towards the receiving piece 21 '. This acceleration causes the cut. After the cut, the plunger armature 4 'can be returned to the starting position by the return spring 49'.

The disadvantage of devices 1 'constructed in this way is to be seen in particular in the fact that their manufacture and assembly is complicated and costly. The yoke 2 'is made of a pressed steel profile. It must be the two holes for the plunger anchor 4 'and the plunger 43' are mounted, and the outer contours are milled. Thereafter, the plunger coil 3 'is inserted, and the likewise made of steel separately receiving piece 21' is pressed into the front hole so that it is surrounded by the plunger coil 3 '. The carrier 1 must also be made separately and the yoke 2 'thereon by means of screws 11', 12 'are attached.

GB-2'065'375 A discloses a magnetic drive with a plunger coil and a U-shaped half-yoke that drive a plunger anchor in a known manner. The plunger coil is wound on a coil holder, which has a flange at its two ends. The two flanges and the two legs of the half yoke are each with one Provide projection or a groove which are designed so accurate that the coil holder engages when inserted into the half-yoke. The coil holder and the half yoke are held together by a mutual elastic positive connection. A disadvantage of this structure is that the production of the half-yoke with its mounted on the inner sides of the legs grooves is expensive. In order to ensure the elasticity required for latching, the legs of the half yoke must be sufficiently thin; However, this requirement is contrary to those for a thick semi-yoke as possible, which is needed to obtain the largest possible magnetic flux through the half-yoke. The half-yoke must also be wide enough to accommodate the coil mount in a U-shaped slot in one of the legs, resulting in a large footprint.

PRESENTATION OF THE INVENTION

It is therefore an object of the invention to provide a cutting device which avoids the disadvantages of the prior art. The cutting device should in particular be made of easily manufactured parts, have a particularly simple structure, be inexpensive, allow a large magnetic flux and occupy little space.

These and other objects are achieved by the inventive cutting device, as defined in the first claim. Advantageous embodiments are given in the dependent claims. A method is also specified for mounting the device according to the invention.

The invention uses a further developed magnetic drive for cutting a thread-like body compared to the prior art.

The inventive device for cutting a thread-like body thus includes a stationary cutting member and a movable, provided with a magnetic drive cutting member whose interaction causes a cut in the thread-like body. The magnetic drive has a stationary plunger coil for generating a Magnetic field, a stationary return yoke, a movably guided, with the movable cutting member operatively connected plunger armature and a support structure which carries at least two stationary elements of the magnetic drive on. The support structure has at least one elastically deflectable arm for forming at least one latching closure, by means of which one of the at least two stationary elements can be fastened to the support structure. The plunger coil, the yoke yoke and the plunger armature are arranged and arranged in relation to one another such that the magnetic field is closed and runs essentially in the plunger armature and in the yoke yoke. The support structure carries and connects to each other the plunger coil, the yoke yoke or part of the yoke yoke, as well as the fixed cutting member.

In a preferred embodiment of the device according to the invention, the carrier structure carries the plunger coil and two half yokes, which act as yoke yokes, and connects them to one another. The half yokes are attached to the support structure via two snap fasteners each. The plunger coil is preferably wound directly on the support structure. The support structure is preferably made of plastic and is manufactured in one piece by injection molding.

The advantages of the invention are particularly evident when the support structure combines as many functions as possible. It is preferably at the same time carrier of the winding of the plunger, positioning and holder for the two Halbjoche, linear guide for the plunger and the plunger, and support for the return spring and positioning and holder for the anvil or the cutting blade.

In the inventive method for mounting the device according to the invention, a support structure is provided, and at least two stationary elements of the magnetic drive are introduced into the support structure. One of the at least two stationary elements is fastened to the carrier structure via at least one latching closure, which is formed by at least one elastically deflectable arm. The plunger coil, the return yoke or a part of the yoke yoke, as well as the fixed cutting member are attached to the support structure and connected to each other.

The advantages achieved by the invention are in particular to be seen in the fact that this device is very easy to assemble, so that unqualified workers or even machines can be entrusted with this task. This construction also reduces the risk of making assembly errors and thus reduces the expected rejects during production.

TITLE OF DRAWINGS

Figuren 1 und 2

zeigen perspektivische Darstellungen einer Schneidvorrichtung gemäss dem Stand der Technik.

Figuren 3 und 4

zeigen eine teilweise explosionsartige perspektivische Ansicht einer Schneidvorrichtung bzw. einen Längsschnitt durch dieselbe.

Figuren 5 und 7

zeigen teilweise explosionsartige perspektivische Ansichten der wichtigsten Teile von drei Ausführungsformen der erfindungsgemässen Vorrichtung.

Figuren 6 und 8

zeigen Längsschnitte durch die Ausführungsformen der Figuren 5 bzw. 7.

In the following the invention will be explained in more detail by means of examples and with reference to the accompanying figures.

Figures 1 and 2

show perspective views of a cutting device according to the prior art.

FIGS. 3 and 4

show a partially exploded perspective view of a cutting device or a longitudinal section through the same.

FIGS. 5 and 7

show partially exploded perspective views of the most important parts of three embodiments of the inventive device.

FIGS. 6 and 8

show longitudinal sections through the embodiments of Figures 5 or 7.

EMBODIMENT OF THE INVENTION

FIGS. 3 and 4 show a cutting device 1. Important parts of the device are held together by a support structure 7, that is supported and interconnected. The support structure 7 is a one-piece injection-molded part made of a plastic, for example. Of polyamide, and may be supplemented with fillers and / or reinforcing materials such as glass fibers. It consists essentially of a bobbin 75, four snap fasteners 71-74 and a bracket 76. The bobbin 75 is z. Example, a tube having a substantially rectangular profile, on which in the construction of the device 1 from the outside, a coil winding of a plunger coil 3 is applied. The profile of Interior of the bobbin 75 and the outer shape of a plunger armature 4 with a rectangular cross-section are matched to one another so that the plunger armature 4 is guided inside the coil support 75 and is movable along its longitudinal direction back and forth. Accordingly, the inner surfaces of the bobbin 75 are formed as guide surfaces suitable. Of the Immersion anchor 4 is made of a ferromagnetic material and is, for example. By means of a screw, connected to a plunger 43, which consists of a non-ferromagnetic material. About the plunger 43, a return spring 49 is slipped so that it surrounds the plunger 43 and in the assembled state, on the one hand on the plunger armature 4 and on the other hand on the bracket 76 is supported. The bracket 76 has a bore 77 through which the plunger 43 passes and in which it is guided. In the assembled state, a knife holder 51 is attached to the plunger 43 via a suitable, preferably detachable connection 52. The knife holder 51 carries, as its name implies, a cutting blade 5, which cooperates with a stationary anvil 6. Between the anvil 6 and the cutting blade 5, the path of a thread-like, longitudinally moved body 9, z. B. a yarn. The snap locks 71-74 serve in pairs the attachment of two substantially U-shaped half yokes 21, 22. They are identical to each other and each have a pair of deflectable arms 81, 82 on. Each arm 81, 82 is provided with inwardly directed lugs 83, 84. The arms 81, 82 are so elastic that they can be deflected outwards.

When assembling the device, a half yoke 21 is inserted from above (or below) into the two associated snap fasteners 71, 73. The guidance of the half-yoke 21 in the longitudinal direction provide stops 85-88; two more such attacks are in the FIG. 1 hidden and therefore not visible. When inserting the half yoke 21, the lugs 83, 84 slide along the half yoke 21, so that the arms 81, 82 are deflected outwards. When the half-yoke 21 has reached its end position, the lugs 83, 84 snap over (or under) it, and the arms 81, 82 return to their final state thanks to their elasticity from their lateral deflection. Thus, the half-yoke 21 is held by the two snap fasteners 71, 73 assigned to it and the stops 85, 87 assigned to it. The plunger armature 4 with the return spring 49 is inserted into the coil carrier 75. At the end of the knife holder 51 is attached to the plunger, which rests on the bracket 76 so that the plunger armature 4 can not be moved out of the bobbin 75. This keeps the device together. The longitudinal axes of plunger coil 3, coil support 75, plunger 4, plunger 43, return spring 49 and cutting blade 5 are preferably centered on each other and coincide in a single longitudinal axis a.

The plunger armature 4 and the half yokes 21, 22 each consist of a ferromagnetic material. In the assembled final state together they form a ferromagnetic core, which is partially enclosed by the plunger coil 3. The two half-yokes 21, 22 serve as the yoke 2 'in the prior art, the closure of two symmetrical to each other magnetic circuits 31, 32, which have a common branch in the plunger armature 4 and can drive the plunger armature 4. In the rear part of the device 1, in the region of the snap-in closures 73, 74, the corresponding legs of the two half yokes 21, 22 are mounted very close to the plunger armature 4, which is movable back and forth in the rear passage 24 formed by them. In the front part of the device, in the region of the snap fasteners 71, 72, the corresponding legs of the half yokes 21, 22 also form a front passage 23 for the plunger armature 4. In its initial position, the plunger armature 4 is outside or at least only partially in the front passage 23 (see also FIG. 4 ). Only the non-ferromagnetic ram 43 protrudes through the front passage 23, but does not affect the magnetic field 31, 32. To trigger the cutting process, the plunger coil 3 is energized, whereby closed magnetic fields 31, 32 in the plunger armature 4 and in the two half-yokes 21, 22 are generated. The magnetic field energy of the system is the smaller, the more the front passage 23 is filled with ferromagnetic material. The system tends to minimize its magnetic field energy and thus to fill the forward passage 23 with the plunger armature 4, so that the plunger armature 4 is accelerated into the front passageway 23. The plunger armature 4 moves according to FIG. 1 to the left against the anvil 6, wherein in a known manner, the thread-like body or the yarn 9 is separated. After the cut, the excitation of the plunger coil 3 is stopped, and the return spring 49 brings the plunger armature 4 to the right in the starting position according to FIG. 4 back.

Calculations show that the force exerted on the plunger armature 4 is independent of its position. On the plunger armature 4 thus acts during its entire movement, an approximately constant Beschennigungskraft. This has the advantage that the plunger armature 4 is accelerated from the beginning with a relatively large force and thus the cut takes place more quickly. In contrast, according to the prior art Figures 1 and 2 the force inversely proportional to the square of the length of the gap 44 '. The Acceleration is therefore very small at the beginning of the movement, for pouring gaps 44 ', and increases sharply only for small gaps 44'. In such a force curve, the cut is made later than the approximately constant force curve according to FIGS. 3 and 4 , However, the invention can be carried out alternatively with the known from the prior art, less advantageous magnetic drive.

The plunger armature 4 and the two half yokes 21, 22 can be produced as simple stamped parts. This is an important advantage over the prior art, where the manufacture of the yoke 2 'is much more complex and expensive.

The support structure 7 united in the device 1 of FIGS. 3 and 4 several functions in itself. It is at the same time carrier of the winding of the plunger coil 3, positioning and holder for the two Halbjoche 21, 22, linear guide for the plunger armature 4 and the plunger 43 and support for the return spring 49. This combination of several functions in a single, easy to produce and inexpensive injection molded part 7 is another advantage.

The entire device 1 shown here is usually installed in a housing, which is not shown here. But it is sufficient a single attachment to connect the entire device to the housing, with several possibilities exist.

FIGS. 5 and 6 show a first embodiment of the inventive device 1. This first embodiment is in many of the device 1 of FIGS. 3 and 4 similar, so here's the one out FIGS. 3 and 4 recognizes already known elements, which are designated by the same reference numerals. A snap fastener 71 is made in this embodiment with only one elastic arm to indicate that there are many possibilities known per se for the snap fasteners 71-74. In deviation from the device 1 of FIGS. 3 and 4 Here is an anvil 6 connected via an anvil support 61 with the lower half yoke 22 or preferably made with this one piece. The part that combines half yoke 22, anvil carrier 61 and anvil 6 in itself can be produced as a simple stamped part. As a result, the device 1 of the FIGS. 5 and 6 compared to the state of the art yet more compact, easier to produce and less expensive. The longitudinal axes of plunger coil 3, coil carrier 75, plunger armature 4, plunger 43, return spring 49, cutting blade 5 and anvil 6 are preferably centered on each other and coincide in a single longitudinal axis a.

In FIGS. 7 and 8 In turn, most of the elements are already recognizable Figures 3-6 are shown. Notwithstanding the devices 1 according to FIGS. 3, 4 respectively. FIGS. 5, 6 Here an anvil 6 is attached to the plunger 43, and a cutting blade 5 is fixedly arranged on a knife carrier 53. Here, like the anvil carrier 61 in the first embodiment, the knife carrier 53 adjoins the lower half yoke 22, but is slightly offset, so that the cutting edge of the cutting knife 5 lies in the axis a, which is the axis of movement and the axis of the coil. The longitudinal axes of plunger coil 3, coil carrier 75, plunger 4, plunger 43, return spring 49, cutting blade 5 and anvil 6 are preferably centered on each other. Of course, the cutting blade 5 could also be fastened differently than at the lower half yoke 22.

LIST OF REFERENCE NUMBERS

1, 1 '

contraption

10 '

carrier

11 ', 12'

screw

2 '

return yoke

21, 22

half-yokes

23

front passage for plunger anchor

24

rear passage for plunger anchor

3, 3 '

moving coil

31, 32

magnetic fields

4, 4 '

plunger

41 '

front end of the plunger anchor

43, 43 '

tappet

44 '

gap

49.49 '

return spring

5, 5 '

cutting blade

51, 51 '

knife holder

52 '

Connection between knife holder and plunger

53

blade carrier

6

anvil

60

anvil surface

61

anvil support

7

support structure

71-74

Einrastverschlüsse

75

coil carrier

76

hanger

77

Hole in the bracket

81, 82

Arms of a snap closure

83, 84

nose

85-88

attacks

9

threadlike body

90

movement direction

a

longitudinal axis

Claims (13)

1. A device (1) for cutting a thread-like body (9), with a stationary cutting element (6) and a moving cutting element (5) provided with a magnetic drive, whose cooperation causes a cut in the thread-like body (9), said magnetic drive comprising
   a stationary plunger-type coil (3) for producing a magnetic field (31, 32),
   a stationary magnetic yoke (21, 22),
   a movably guided plunger-type armature (4) actively connected to the moving cutting element (5), and
   a carrier structure (7) which carries at least two stationary elements (3, 21, 22) of the magnetic drive,
   wherein
   the plunger-type coil (3), the magnetic yoke (21, 22) and the plunger-type armature (4) are of a nature and are arranged with respect to one another, such that the magnetic field (31, 32) is closed and runs essentially in the plunger-type armature (4) and in the magnetic yoke (21, 22),
   characterized in that
   said carrier structure (7) comprises at least one elastically deflectable arm (81, 82) for forming at least one lock-in closure (71-74) adapted for fastening one of the at least two stationary elements (3, 21, 22) on the carrier structure (7), and
   the carrier structure (7) carries and connects to one another the plunger-type coil (3), the magnetic yoke (21, 22) or a part of the magnetic yoke (21), and the stationary cutting element (6).
2. The device (1) according to claim 1, wherein the plunger-type coil (3) is wound directly on the carrier structure (7).
3. The device (1) according to one of the preceding claims, wherein the magnetic yoke (21, 22) or the part of the magnetic yoke (21) is fastened on the carrier structure (7) via the at least one lock-in closure (71-74) and preferably two lock-in closures (71, 73),
4. The device (1) according to claim 3, wherein the at least one lock-in closure (71) comprises two elastically deflectable arms (81, 82) which engage around the magnetic yoke (21, 22) or the part of the magnetic yoke, with a positive fit.
5. The device (1) according to one of the preceding claims, wherein the magnetic yoke (21, 22) contains two semi-yokes (21, 22) which are arranged symmetrically to the plunger-type coil (3), for forming two magnetic circuits (31, 32).
6. The device (1) according to one of the preceding claims, wherein the carrier structure (7) is manufactured of one piece.
7. The device (1) according to one of the preceding claims, wherein the carrier structure (7) is manufactured of plastic, for example polyamide, and is preferably manufactured by injection molding.
8. The device (1) according to one of the preceding claims, wherein the carrier structure (7) forms a guide for the plunger-type armature (4).
9. The device (1) according to one of the preceding claims, wherein the stationary cutting element (6) is designed as one piece with the magnetic yoke or a part of the magnetic yoke (22).
10. The device (1) according to one of the preceding claims, wherein the stationary cutting element is an anvil (6) and the moving cutting element is a cutting knife (5).
11. The device (1) according to one of the claims 1-9, wherein the stationary cutting element is a cutting knife (5) and the moving cutting element is an anvil (6).
12. The device (1) according to one of the preceding claims, wherein a restoring spring (49) is arranged between the plunger-type armature (4) and the carrier structure (7).
13. A method for the assembly of the device (1) according to one of the preceding claims, wherein
    a carrier structure (7) is provided, and
    at least two stationary elements (3, 21, 22) of the magnetic drive are introduced into the carrier structure (7),
    characterized in that
    one of the at least two stationary elements (3, 21, 22) is fastened to the carrier structure (7) via at least one lock-in closure (71.74) which is formed by at least one elastically deflectable arm (81, 82), and
    the plunger-type coil (3), the magnetic yoke (21, 22) or a part of the magnetic yoke (21), and the stationary cutting element (6) are fastened on the carrier structure (7) and thus connected to one another.

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