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Title:
SENSOR DEVICE AND METHOD FOR DETECTING AN ABNORMAL CONDITION OF A WASTE RIBBON
Document Type and Number:
WIPO Patent Application WO/2020/048614
Kind Code:
A1
Abstract:
The invention relates to a sensor device and a method for detecting an abnormal condition of a waste ribbon in a weaving machine comprising a block (2) with a guide element (3) for the waste ribbon, wherein in a normal condition of the waste ribbon the block (2) is arranged in a nominal position, wherein the block (2) is mounted slidably along a movement path of the waste ribbon, such that the block (2) is slideable out of the nominal position in a direction opposite to the normal movement direction of the waste ribbon by forces acting on the block (2) in said direction opposite to the normal movement direction of the waste ribbon.

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JPH0619581A selvedge device
Inventors:
VERREPT SEBASTIAAN (BE)
VANDECASTEELE KOENRAAD (BE)
Application Number:
PCT/EP2018/074174
Publication Date:
March 12, 2020
Filing Date:
September 07, 2018
Export Citation:
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Assignee:
PICANOL (BE)
International Classes:
D03D47/40
Foreign References:
EP2570530A12013-03-20
JPS56103076U1981-08-12
JPS5245070U1977-03-30
JPS56103076U1981-08-12
Attorney, Agent or Firm:
PATENTANWÄLTE RUFF, WILHELM, BEIER, DAUSTER & PARTNER MBB (DE)
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Claims:
CLAIMS

1. Sensor device for detecting an abnormal condition of a waste ribbon in a weaving machine comprising a block (2) with a guide element (3) for the waste ribbon, wherein in a normal condition of the waste ribbon the block (2) is arranged in a nominal position, wherein the block (2) is mounted slidably along a movement path of the waste ribbon, such that the block (2) is slideable out of the nominal position in a direction opposite to the normal movement direction of the waste ribbon by forces acting on the block (2) in said direction opposite to the normal movement direction of the waste ribbon.

2. Sensor device according to claim 1 , characterized in that a proximity sensor (9) is provided, wherein a presence or absence of the block (2) in the nominal position is detectable by the proximity sensor (9).

3. Sensor device according to claim 1 or 2, characterized in that a guide shaft (4) is provided, wherein the block (2) is mounted to the guide shaft (4) slidably along the guide shaft (4).

4. Sensor device according to claim 3, characterized in that a mounting bracket (5) having two wings (6) is provided, wherein the guide shaft (4) is mounted between the wings (6) of a mounting bracket (5), wherein each wing (6) is provided with a guide element (7) for the waste ribbon, wherein in particular the guide elements (7) are aligned to each other along an axis extending parallel to the guide shaft (4).

5. Sensor device according to claim 4, characterized in that a movement of the block (2) in the normal movement direction of the waste ribbon towards a first wing (6) of the mounting bracket (5) is limited by an abutment element (8).

6. Sensor device according to any one of claims 3 to 5, characterized in that the block (2) is rotatably mounted to the guide shaft (4), wherein a force is applied to the block (2) for rotating the block (2) about the guide shaft (4) out of the nominal position, and wherein the block (2) is held in the nominal position against said force by a waste ribbon having a predefined tension.

7. Sensor device according to claim 6, characterized in that the block (2) is provided with a detection face (10), wherein the block (2) is considered to be arranged in the nominal position as long as the detection face (10) is arranged within a defined area.

8. Sensor device according to claim 7, characterized in that the guide element (3) for the waste ribbon of the block (2) is a guide eye, wherein an axis of this guide eye and a rotation axis (18) of the block (2) lie in a middle plane (13) of the block (2), and wherein the detection face (10) is arranged asymmetrically with respect to the middle plane (13).

9. Method for detecting an abnormal condition of a waste ribbon in a weaving machine, wherein the waste ribbon is guided by a block (2), which block (2) is arranged slidably along a movement path of the waste ribbon, wherein in a normal condition of the waste ribbon the block (2) is arranged in a nominal position, and wherein if the waste ribbon is moved in a direction opposite to its normal movement direction, the waste ribbon exerts a force on the block (2) in said direction opposite to the normal movement direction of the waste ribbon and the block (2) is moved in said direction opposite to the normal movement direction of the waste ribbon out of the nominal position.

10. Method according to claim 9, characterized in that a presence or absence of the block (2) in the nominal position is detected by a proximity sensor (9).

1 1. Method according to claim 9 or 10, characterized in that the block (2) is arranged rotatably about a rotation axis (18) extending at least essentially parallel to the movement path of the waste ribbon, wherein a force is applied to the block (2) for rotating the block (2) about the rotation axis (18) out of the nominal position, and wherein the block (2) is held in the nominal position against said force by a waste ribbon having a predefined tension.

Description:
Sensor device and method for detecting an abnormal condition of a waste ribbon

TECHNICAL FIELD AND PRIOR ART

The invention relates to a sensor device and a method for detecting an abnormal condition of a waste ribbon in a weaving machine. JP 56-103076-U shows a weaving machine with a sensor device for detecting a tension drop of a waste ribbon comprising a lever arranged swivellable about a swivel axis, wherein the lever is held in a first position at a distance from a contact by a waste ribbon against gravitational forces acting on the lever, and due to the gravitational forces, the lever is swivelled to a second position, in which the lever contacts the contact, in case a tension in the waste ribbon drops below a set value.

SUMMARY OF THE INVENTION

It is the object of the invention to provide a sensor device and a method for detecting an abnormal condition of a waste ribbon in a weaving machine.

This object is solved by the device and the method with the features of claims 1 and 9. Preferred embodiments are defined in the dependent claims.

According to a first aspect, a sensor device for detecting an abnormal condition of a waste ribbon in a weaving machine comprising a block with a guide element for the waste ribbon is provided, wherein in a normal condition of the waste ribbon the block is arranged in a nominal position, and wherein the block is mounted slidably along a movement path of the waste ribbon, such that the block is slideable out of the nominal position in a direction opposite to the normal movement direction of the waste ribbon by forces acting on the block in said direction opposite to the normal movement direction of the waste ribbon.

The waste ribbon contacts the block at the guide element. Thus, in use, in a normal condition the waste ribbon exerts a force on the block in its movement direction. In an abnormal condition, forces acting on the block in an opposite direction could be applied by a waste ribbon pulled backwards, i.e. pulled in a direction opposite to its normal movement direction, for example in case the waste ribbon is clamped between a fabric take-up device. The guide element for the waste ribbon in one embodiment is a guide groove. In other embodiments, the guide element is a guide eye.

In one embodiment, a proximity sensor is provided, wherein a presence or absence of the block in the nominal position is detectable by the proximity sensor. In one embodiment, the block has a detection face, wherein the block is considered to be arranged in the nominal position as long as the detection face is arranged within a defined area opposite to the proximity sensor, i.e. as long as the detection face is detectable by the proximity sensor.

In preferred embodiment, at least in the region of the sensor device the waste ribbon is moved along an at least essentially linear movement path, wherein the block is mounted slidably along a linear path. In one embodiment, a guide shaft is provided, wherein the block is mounted to the guide shaft slidably along the guide shaft. In the context of the application, a movement “along the guide shaft” describes a movement in the axial direction of the guide shaft. The block is provided with a groove or a through hole accommodating the guide shaft. The guide shaft is arranged at least essentially in parallel to the movement path of the waste ribbon.

In one embodiment, the guide shaft is mounted between wings of a mounting bracket, in particular between two wings of a mounting bracket, wherein each wing is provided with a guide element for the waste ribbon. The two guide elements define a movement path of the waste ribbon. In preferred embodiments, the guide elements are aligned to each other along an axis extending parallel to the guide shaft. The guide elements for the waste ribbon in one embodiment each are formed by a guide groove, in other embodiments, the guide elements are guide eyes.

In one embodiment, the block is moveable over the full length of the guide shaft between the wings of the mounting bracket. In preferred embodiments, a movement of the block in the normal movement direction of the waste ribbon towards a first wing of the mounting bracket is limited by an abutment element. In normal conditions, the waste ribbon in use exerts a force on the block in its movement direction forcing the block against the abutment element. The abutment element ensures a precise and repeatable positioning of the block in the nominal position.

In one embodiment, the block has only one degree of freedom, i.e. a movement of the block is limited to the movement along the movement path of the waste ribbon. In preferred embodiments, the block is further rotatably mounted to the guide shaft, wherein a force is applied to the block for rotating the block about the guide shaft out of the nominal position, and wherein the block is held in the nominal position against said force by a waste ribbon having a predefined tension. In other words, the block is slideable out of the nominal position as well as rotatable out of the nominal position, wherein either one of the movements out of the nominal position can be detected, for example by means of the proximity sensor. In one embodiment, the guide shaft is horizontally arranged, wherein the gravitational forces are acting on the block for rotating the block about the guide shaft out of the nominal position. In alternative or in addition, in embodiments of the invention biasing force elements, such as spring elements are provided for forcing the block out of the nominal position. In this case, the guide shaft in one embodiment is not horizontally arranged.

In preferred embodiments, the block is provided with a detection face, wherein the block is considered to be arranged in the nominal position as long as the detection face is arranged within a defined area. The block is at least slideable such that the detection face can be moved out of the defined area. In embodiments, in addition the block is rotatable such that the detection face can be moved out of the defined area.

In one embodiment, the guide element for the waste ribbon of the block is a guide eye, wherein an axis of this guide eye and a rotation axis of the block lie in a middle plane of the block, wherein the detection face is arranged asymmetrically with respect to the middle plane. With this design, an angle of rotation at which the detection face is moved out of the defined area depends on the orientation, in which the block is mounted to the guide shaft. Hence, by removing the block from the guide shaft, rotating the block 180° and re-mounting the block to the guide shaft a sensitivity of the sensor device to deviations in a waste ribbon tension can be modified.

According to a second aspect, a method for detecting an abnormal condition of a waste ribbon in a weaving machine is provided, wherein the waste ribbon is guided by a block, which block is arranged slidably along a movement path of the waste ribbon, wherein in a normal condition of the waste ribbon the block is arranged in a nominal position, and wherein if the waste ribbon is moved in a direction opposite to its normal movement direction, the waste ribbon exerts a force on the block in said direction opposite to the normal movement direction of the waste ribbon and the block is moved in said direction opposite to the normal movement direction of the waste ribbon out of the nominal position.

In one embodiment, a presence or absence of the block in the nominal position is detected by a proximity sensor. In one embodiment, the block is only moveable along a movement path of the waste ribbon. In preferred embodiments, in addition the block is arranged rotatably about a rotation axis extending at least essentially parallel to the movement path of the waste ribbon, wherein a force is applied to the block for rotating the block about the rotation axis out of the nominal position, and wherein the block is held in the nominal position against said force by a waste ribbon having a predefined tension.

BRIEF DESCRIPTION OF THE DRAWINGS

In the following, embodiments of the invention will be described in detail with reference to the drawings. Throughout the drawings, the same elements will be denoted by the same reference numerals.

Fig. 1 is a perspective view from a front of a first embodiment of a sensor device for detecting an abnormal condition of a waste ribbon in a weaving machine, which preferably is arranged at a right side of a weaving machine,

Fig. 2 shows the sensor device of Fig. 1 in a perspective view from behind in a normal condition of a waste ribbon;

Fig. 3 shows the sensor device of Fig. 2 in a perspective view from behind in an abnormal condition of a waste ribbon;

Fig. 4 is a front view of the sensor device of Fig. 1 in the normal condition of a waste ribbon of Fig. 2; Fig. 5 is a front view of the sensor device of Fig. 1 in the abnormal condition of a waste ribbon of Fig. 3;

Fig. 6 is a side view of the sensor device of Fig. 1 with a first sensitivity arrangement in the normal condition of the waste ribbon as shown in Fig. 3;

Fig. 7 is a side view of the sensor device of Fig. 6 in another abnormal condition of a waste ribbon;

Fig. 8 is a side view of the sensor device of Fig. 6 with a second sensitivity arrangement in the normal condition of the waste ribbon as shown in Fig. 3; and Fig. 9 is a perspective view from a front of a second embodiment of a sensor device for detecting an abnormal condition of a waste ribbon in a weaving machine, which preferably is arranged at a left side of a weaving machine.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION Figs. 1 to 8 show a first embodiment of a sensor device 1 for detecting an abnormal condition of a waste ribbon (not shown) in a weaving machine.

The sensor device 1 comprises a block 2 with a guide element 3 for the waste ribbon. The block 2 is mounted to a guide shaft 4. In the embodiment shown, the block 2 is slidably and rotatably mounted to the guide shaft 4 so that the block 2 can slide along the guide shaft 4 and rotate about the guide shaft 4.

The sensor device 1 comprises a mounting bracket 5 with two parallel wings 6 and a cantilever 1 1 arranged perpendicular to the two wings 6.

The guide shaft 4 is mounted between the wings 6 of the mounting bracket 5, wherein in the embodiment shown, the guide shaft 4 is mounted to the mounting bracket 5 by means of bolts 14, 15. Each wing 6 is provided with a guide element 7 for the waste ribbon.

In the embodiment shown, the guide shaft 4 is provided with an abutment element 8, wherein a movement of the block 2 towards a first wing 6 of the mounting bracket 5, which is shown on the right in Fig. 1 , is limited by the abutment element 8. The other wing 6 is referred to as second wing 6 in the following. The sensor device 1 further comprises a proximity sensor 9 with a cable 12, which is mounted to the cantilever 11 of the mounting bracket 5. The proximity sensor 9 cooperates with a detection face 10 of the block 2 as explained in more detail in the following.

In the embodiment shown, the guide element 3 of the block 2 and the guide elements 7 in the wings 6 are guide eyes, wherein a waste ribbon (not shown) is threaded through the guide element 7 provided at the second wing 6 (on the left in Fig. 1 ), through the guide element 3 of the block 2 and through the guide element 7 provided at the first wing 6. Hence, in a normal operation, the waste ribbon is moved from the left to the right in Fig. 1 , wherein the moving waste ribbon exerts a force on the block 2 forcing the block 2 towards the abutment element 8. The expressions“left” and “right” used in the context of the application are only used for describing a position of elements with respect to one another and do not limit the arrangement of the sensor device 1 on a weaving machine.

An axis 17 of the guide element 3 of the block 2 and a rotation axis 18 of the block 2 lie in a middle plane 13, indicated by a broken line. The block 2 shown in Figs. 1 to 8 is provided with three indications 16, wherein two indications 16 are provided at a common first part of the block 2 with respect to the middle plane, and one indication 16 is provided at an opposite second part of the block 2.

The guide shaft 4 is horizontally arranged, wherein gravitational forces acting on the block 2 cause a rotation of the block 2 about the guide shaft 4 until an equilibrium is reached. In case a waste ribbon with a sufficient tension is threaded through the guide elements 3 and 7, a rotation of the block 2 is prevented. In case a tension of the waste ribbon drops, the block 2 will rotate about the guide shaft 4 due to the gravitational forces acting on the block 2. In the embodiment shown, a center of gravity of the block 2 and the detection face 10 are arranged at opposite sides of the guide shaft 4, i.e. when the center of gravity is moved downwards, the detection face 10 is moved upwards. In other embodiments, the center of gravity of the block 2 and the detection face 10 are arranged at the same side of the block 2 with respect to the guide shaft 4.

Figs. 1 , 2, 4, 6 and 6 and 8 show a normal condition of a waste ribbon, wherein the detection face 10 is arranged opposite to the proximity sensor 9. In the context of the application, the block 2 is considered to be arranged in a nominal position as long as the detection face 10 is arranged within a defined area, and, thus detectable by the proximity sensor 9.

The sensor device 1 shown in the figures is suitable for detecting two distinct abnormal conditions.

Figs. 3 and 5 show a first abnormal condition, wherein the block 2 is moved along the guide shaft 4 out of the nominal position. Such a movement of the block 2 is caused by forces acting on the block 2 in a direction opposite to the normal movement direction of the waste ribbon, i.e. from the right to the left in Fig. 1. Such forces are applied to the block 2 for example if the waste ribbon is moved in a direction opposite to its normal movement direction, i.e. from the right to the left in Figs. 1 and 4. When the block 2 moves along the guide shaft 4, hence, to the left in Figs. 1 and 4, the detection face 10 of the block 2 will move away from the proximity sensor 9 and the proximity sensor 9 will give no signal. This can be an indication that something is wrong with the waste ribbon, and the weaving machine can be stopped. It will be understood by the person skilled in the art that a travel path of the block 2 before the detection face 10 leaves the sensing range of the proximity sensor 9 depends among others on a dimension of the block 2 in the axial direction of the guide shaft 4 and a length of the abutment element 8.

Fig. 7 shows a second abnormal condition, wherein the block 2 is rotated about the guide shaft 4 out of the nominal position shown in Fig. 6. Such a rotation of the block 2 is caused for example by gravitational forces acting on the block 2, in case a waste ribbon tension is not sufficient to balance the gravitational forces.

As shown in Fig. 6 and 8, the detection face 10 is arranged asymmetrically with respect to the middle plane 13. The block 2 can be mounted to the guide shaft 4 in two orientations as shown in Figs. 6 and 8, the orientations being rotated 180° with respect to each other. A sensitivity to deviations in the waste ribbon tension depends on the orientation of the block 2.

Fig. 6 shows a first orientation, also referred to as sensitive arrangement, wherein the first part of the block 2 provided with two indications 16 is arranged above the second part of the block 2 provided with only one indication 16. In this orientation, the detection face 10 extends only over a small distance downwards from a neutral position, in which the middle plane 13 is aligned with a central axis of the proximity sensor 9. Thus, a small rotation of the block 2 about the guide shaft 4 causes the detection face 10 to move upwards and out of the range of the proximity sensor 9. In other words, when the block 2 rotates a small amount, then a signal of the proximity sensor 9 already drops.

Fig. 8 shows a second orientation, also referred to as non-sensitive arrangement, wherein the first part of the block 2 provided with two indications 16 is arranged below the second part of the block 2 provided with only one indication 16, wherein the indications 16 are not visible in Fig. 8. With this orientation, compared to the sensitive arrangement, the detection face 10 extends over a larger distance downwards from a neutral position, in which the middle plane 13 is aligned with a central axis of the proximity sensor 9. Hence, compared to the sensitive arrangement, the block 2 may rotate about the guide shaft 4 over a larger angle before a signal of the proximity sensor 9 will drop. In other words, when an end of the block 2 opposite to the detection face 10 is moved downwards due to gravity and the detection face 10 is moved upwards, the proximity sensor 9 continues to measures a signal even if the block 2 has been rotated about a larger angle compared to the sensitive arrangement. The sensor device 1 shown in Figs. 1 to 8 preferably is arranged at a right side of a weaving machine, wherein the waste ribbon moves in a normal condition from the left to the right.

Fig. 9 is a perspective view from a front of a second embodiment of a sensor device 1 for detecting an abnormal condition of a waste ribbon in a weaving machine, which preferably is arranged at a left side of a weaving machine, wherein the waste ribbon moves in a normal condition from the right to the left. The sensor device 1 shown in Fig. 9 essentially corresponds to the sensor device 1 shown in Figs. 1 to 8 and for the same or similar elements coinciding reference signs are used.

In contrast to the embodiment shown in Figs. 1 to 8, in the embodiment of Fig. 9, the abutment element 8 is provided on the second wing 6, shown on the left in Fig. 9. In a normal operation, the waste ribbon (not show) is moved from the right to the left in the drawing plane forcing the block 2 against the abutment element 8.