DE102012108417A1 - Conductor loop for use in conveyer belt, has electrically conductive structure or material arranged in loop, where loop is enclosed in carrier side cover plate and in machine side cover plate by electrically conductive fabric insulation - Google Patents

Abstract

The loop (15) has a carrier side cover plate (10a) and a machine side cover plate (10b) that are provided with a polymeric material comprising elastic properties. An electrically conductive structure or material is arranged in the loop, where the loop is enclosed in the carrier side cover plate and in the machine side cover plate by an electrically conductive fabric insulation. The insulation is arranged with a coating or an encapsulation, and is arranged with an elastomer hose or a heat shrink sleeve. An independent claim is also included for a conveyer belt.

Description

The invention relates to a conductor loop according to the preamble of claim 1.

It has long been known to monitor the occurrence of longitudinal slots in conveyor belts. For this purpose, conductor loops can be introduced into the conveyor belt and, by means of a slot protection system, e.g. be checked in the form of a transmitter / receiver combination by means of electromagnetic induction on their integrity. As a result, a conveyor system should be stopped when a longitudinal slot or other major damage to the belt in the direction of A is created.

A conductor loop is an arrangement consisting of one or more endlessly connected (short-circuited) contours of an arbitrary shape, such as e.g. meandering, eight-shaped, straight, etc. exists. The contours may include various materials and construction elements such as e.g. Steel wire, steel cord, conductive textile thread, conductive mesh, conductive elastomeric material, etc. The conductor loops can be embedded directly or in an elastomer package during the production of a conveyor belt or else later in the upper or lower cover plate of the conveyor belt, e.g. be vulcanized at a distance d of about 50 m to 200 m.

A slot protection system is an electronic assembly comprising a transmitter / receiver pair which cooperates with a conductor loop of the conveyor belt according to the principle of electromagnetic induction and thereby determines whether the conductor loop is closed (undamaged) or open (damaged / destroyed).

For example, a slot protection system may have a polling station (combination of transmitter and receiver), possibly proximity detectors (or transponders) and a monitoring station (scanner). During operation of the conveyor belt system, the conductor loops are interrogated by the interrogation station. When a conductor loop passes the interrogation station, an intact conductor loop transmits an electromagnetic signal from the transmitter to the receiver via the conductor loop. The transmitter generates an alternating magnetic field that generates a current in the conductive closed contours of the conductor loop. This current in turn generates a magnetic field that is registered by the receiver (principle of electromagnetic induction).

If the conveyor belt is slotted in the conveying direction, so that the contours of the conductor loop damaged or destroyed and the transmission link transmitter / receiver is interrupted, no signal is transmitted from the transmitter to the receiver. As a result, the longitudinal slot can be detected. In this case, the conveyor belt is stopped by the slot protection system to limit the extent of damage. The maximum possible length of the slot is thereby limited to the distance d between two adjacent conductor loops.

For use as a conductor loop different contours of different materials and construction elements are known. A conductor loop often consists of meandering metal cables, in particular steel cables. The ropes in turn usually consist of at least five strands or wires. Preference is given to a cable structure of the type 7 × 7 with a single wire diameter of about 0.2 mm and a total diameter of 1.5 mm to 2 mm. There are also variants that consist of a mixed structure of copper strands and steel strands, wherein in particular the steel strands encase the copper strands. Also a version, consisting of a massive, steel wire wrapped copper wire, is known. Twines or threads can be used instead of ropes. A twine is a linear fabric made from two or more twined yarns. Each yarn consists of several twisted filaments or fibers.

The DE 10 2009 025 848 A1 describes a conductor loop referred to as a hydrolytic loop. The Hydribleiterschleife has at least one hybrid thread, which in turn consists of at least one textile first material and a conductive second material, and forms the conductor loop after its endless closure. Preferably, at least two hybrid threads form a thread composite, in particular in the form of a cord or twine.

In all these variants, the contours must be connected to form an endless conductor loop. Depending on the number of contours to be used for the closed conductor loop, correspondingly many connection points can arise. Thus, for a 7x7 type rope construction, up to seven joints may be required. These joints can be designed differently. So rope strands are often spliced and soldered or even just soldered.

A disadvantage of the use of such slot protection systems that it comes after prolonged use of the conveyor belts more often false alarms that are triggered by the conductor loops were damaged or destroyed without a longitudinal slot has occurred in the conveyor belt. This can have different causes:
The known conductor loops are exposed to a risk of corrosion. For example, water can or moisture due to damage to the conveyor belt, in particular its cover plate, penetrate into this and damage in contact with the conductor loops by corrosion or destroy, at least for the signal transmission in the context of a slot protection system unusable. This risk of corrosion is exposed both to conventional conductor loops of, for example, steel cables and hybrid conductor loops, which have at least one corrodible material.

Also, known steel conductor loops can be used when folding the conveyor belt in a conveyor belt turn, e.g. due to an accident, to be destroyed.

Likewise, in known conductor loops, the loading and fatigue strength at a Biegewechsel- or loading of the conveyor belt is not sufficient. Thus, in the case of bulk material impact, strong local strains and compressions, in particular of a steel cable contour, can be caused by e.g. a meander-shaped design of the contour can not be compensated sufficiently.

Furthermore, in the known conductor loops, the manufacturing process for the connection points of the conductor loops are very expensive. This is the case in particular with steel cord contours, in which each individual steel cord contour or several strands of a steel cord contour must be spliced separately and subsequently soldered.

The object of the present invention is to provide a conductor loop of the type described above, which has improved protection against external influences.

The object is achieved by the features of the characterizing part of claim 1. Advantageous developments are described in the subclaims.

Thus, the present invention relates to a conductor loop which is completely embedded in a body. The body has a polymeric material with elastic properties. An electrically conductive structure forms the conductor loop after its endless closure. The conductor loop is characterized in that the conductor loop is surrounded by insulation embedded in the body.

The invention is based on the finding that the contours of a conductor loop, in particular a textile conductor loop or a hybrid conductor loop embedded in an elastic body, can be chemically or mechanically attacked and damaged or even destroyed by the constituents of the elastomeric material.

For example, the conductive materials of the conductor loop may oxidize without insulation to the elastomeric material in the vulcanized state, or may be oxidized by e.g. Sulfur corrode. Also, in the course of use, the elastomeric material may migrate between the filaments or fibers of the conductor loops and force them apart so that their mechanical stability is reduced or they may rupture. In other words, by dynamic loading, the elastomeric material can separate the filaments or fibers of the conductor loops and thus disassemble the yarns.

This can be avoided according to the invention in that by means of this insulation a separation of the contours of the conductor loop from the flowing polymeric material with elastic properties (elastomeric material) during vulcanization and also during operation can be achieved.

It is also advantageous that the insulation of the conductor loop increases its elongation at break and thus the loading and the fatigue strength at a bending cycle stress of the conductor loop.

It is also advantageous that the insulation additionally protects the conductor loop from external influences, such as, for example, Water, dirt, oil and the like protects that can occur through a damaged cover plate of a conveyor belt. By penetration of e.g. Water in the cover plate of the conveyor belt to the depth of the conductor loops could be caused by this corrosion, which can lead to damage or even destruction of the conductor loops.

All of these advantages, individually or jointly, increase the life of the conductor loop.

The insulation may be provided by a plastic coating or sheath, e.g. made of TPU, or also by an elastomer tube or shrink tube, e.g. made of polyolefin, are provided. The insulation is provided around the conductor loop before it is embedded in the elastomeric material and then vulcanized.

The conductor loop is thereby produced from an electrically conductive structure which comprises a metallic material, such as e.g. Copper or steel, or also a polyamide (PA), aramid, polyester (PES), polyvinyl acetal (PVA), polyimide (PI), polyetheretherketone (PEEK), polyphenylene or a copolymer, or a combination of two or more of these materials , Of the group of polyphenylenes in particular a polyphenylene sulfide (PPS) is important.

According to one aspect of the invention, the insulation has a coating or sheathing.

It is advantageous here that the electrical conductivity of a conductor loop is not impaired. Furthermore, the sheath thickness is typically in the micrometer range, e.g. between 100 microns and 200 microns, so that the total thickness of a textile conductor loop by the insulation increases only slightly. This is very important because the total thickness of a conductor loop affects the selection of the minimum cover plate thickness of a conveyor belt.

The jacket may e.g. thermoplastic polyurethane (TPU), preferably made of TPU.

According to a further aspect of the invention, the insulation has an elastomer tube or shrink tube.

It is advantageous here that such hoses are commercially available as commercially available products and can be handled easily to produce an insulation according to the invention.

According to a further aspect of the invention, the endless closure of the conductor loop takes place at the connection point by means of splicing and / or clamping.

The advantage here is that the endless closure of the conductor loop is simplified. This can be made faster and cheaper. Also, a spliced and / or clamped joint may have higher strength than known solutions and thereby increase the life of the conductor loop.

While it has hitherto been customary to provide such joints at e.g. Spliced corded and soldered or perform only soldered, the connection in the electrically conductive textile structure by providing a splice and or or clamping over the entire width of the conductive textile structure or by multiple splices and or or clamps over several yarns or about each individual yarn separately. Prior to splicing and / or clamping, the yarns to be joined are preferably twisted together or otherwise routed around each other to produce an overlap of the respective yarn ends in the region of the splice and / or clamping. If an insulation is already provided around the electrically conductive textile structure, it must be removed at least in the region of the ends of the yarns in which the splice and / or clamping is to take place. Preferably, a shrunken tube is used as clamping, which serves as an insulation of the joint against the surrounding elastomer material at the same time. Further, as an additional reinforcement of the joint, the clamping may be achieved by a sleeve clamping, e.g. a ferrule, done.

According to a further aspect of the invention, at least the connection point of the endlessly closed conductor loop is surrounded by at least one shrunken shrinking tube.

The advantage here is that with the splice and or or clamping through the overlying at least one shrunken shrink tubing, the costly and time-consuming splices solder connections or solder joints of the strands of a steel cable at several points, as previously in a reliable commercial Steel conductor loop is common, can be saved. This advantageously benefits the life of the conductor loop.

According to a further aspect of the invention, the conductor loop has a textile transverse reinforcement.

The advantage here is that by means of a textile cross armor, which is also referred to as a breaker, a reinforcement of the conductor loop can be made against loading. As a result, the Beaufschlagungsfestigkeit the entire conductor loop and thus their life can be increased. As textile crosswise reinforcement, e.g. Polyesler polyamide (EP) fabric can be used.

The invention further relates to a conveyor belt having a body comprising a polymeric material having elastic properties, a strength member disposed in the body, and at least one conductor loop according to any one of claims 1 to 6 fully embedded in the body.

In this way, the advantageous properties of the conductor loop according to the invention can be used in a conveyor belt as part of a slot protection monitoring.

According to one aspect of the invention, the body has a support-side cover plate and / or a running-side cover plate of the conveyor belt, in which at least one conductor loop is embedded.

It is advantageous here that the conductor loop can be provided in this arrangement in the region of the conveyor belt, which is to be monitored for slot formation.

According to another aspect of the invention, the junction of the conductor loop is outside arranged the Gutbeaufschlagungsbereiches of the conveyor belt.

It is advantageous in this case that a load on the connection points of the conductor loops can be avoided or at least reduced by the application of the material. This benefits the durability of the joints and thus the life of the conductor loops. Preferably, the connection points are provided as close to the lateral edge of the conveyor belt, to be outside the Gutbeaufschlagungsbereiches and with the greatest possible distance to this.

According to a further aspect of the invention, a first connection point of a first conductor loop and a second connection point of a second conductor loop are located diagonally opposite the surface enclosed by the conductor loops in the plane of the conveying direction A.

It is advantageous in this case that in the case that a Gutbeaufschlagung on one side beyond the Gutbeaufschlagungsbereich beyond, only one connection point is thereby burdened. In other words, by a non-central bulk material in a task or transfer point or other unbalanced mechanical impairment of a conveyor belt, which may be caused by a conveyor, not both joints simultaneously strained but only a junction.

An embodiment and further advantages of the invention are explained below in connection with the following figures. It shows:

1 a perspective schematic representation of a conveyor belt system with slot protection system;

2 a perspective schematic sectional view of a conveyor belt;

3 a schematic plan view of a cut conductor loop package with two conductor loops;

4 a schematic plan view of a cut conductor loop package with a conductor loop;

5 a schematic sectional view of an electrically conductive structure with an insulation, which is embedded in an elastomeric material;

6 a schematic sectional view of a connection point of an electrically conductive structure;

7 a perspective schematic sectional view of a conveyor belt with electrically conductive structure with a textile cross reinforcement; and

8th a schematic plan view of a cut conveyor belt with two conductor loops with diagonally opposite joints.

1 shows a perspective schematic representation of a conveyor belt system 1 with slot protection system 13 . 14 . 16 . 17 , 2 shows a perspective schematic sectional view of a conveyor belt 10 , The conveyor belt system 1 has a closed conveyor belt 10 with a support-side cover plate 10a for receiving or transporting conveyed goods and a run-side cover plate 10b for unrolling on guide, support or drive elements 11 . 12 on. Between these two cover plates 10a . 10b is a strength carrier 18 embedded in the form of steel cables.

The conveyor belt 10 is at one end by means of a drive drum 11 , which rotates in the direction of rotation U, driven in the conveying direction A (belt running direction). The other end of the conveyor belt 10 is by means of a reversing drum 12 circumferentially rotatably tensioned and held. At a Gutbeaufschlagungsposition G of the conveyor belt system 1 can conveyed goods on the support-side cover plate 10a of the conveyor belt 10 abandoned and moved in the conveying direction A.

In the support-side cover plate 10a of the conveyor belt 10 are at a distance d several conductor loops 15 embedded. These conductor loops 15 can only have a single conductor loop 15 or also an arrangement of several conductor loops 15a . 15b exhibit.

3 shows a schematic plan view of a cut conductor loop package 15 with two conductor loops 15a . 15b that are concentric meandering in the plane of the conveyor belt 10 run. The first conductor loop runs 15a around the second conductor loop 15b around.

4 shows a schematic plan view of a cut conductor loop package 15 with a conductor loop 15a , This conductor loop 15a runs in the plane of the conveyor belt 10 eight shaped. The contour of the conductor loop intersects 15a without touching each other.

The slot protection system 13 . 14 . 16 . 17 has a transmitter 16 on, which is an electromagnetic signal in the direction of the conveyor belt 10 sending out. The position of the conductor loops 15 can be independent of the rotational speed U and of the Conveying direction A absolute or relative to the adjacent conductor loops 15 For example, be determined using proximity sensors, for example, on the reversing drum 12 are located. There are also known solutions for determining the position based on a transponder. Furthermore, the position of the conductor loops 15 by means of appropriate marking on the conveyor belt 10 be recognized.

For an intact contour of the conductor loop 15 is due to the electromagnetic signal of the transmitter 16 a changing magnetic field around the contour of the conductor loop 15 generated, which in turn in the contour of the conductor loop 15 causes a current. This current in turn generates a magnetic field around the contour of the conductor loop 15 that from a receiver 17 is registered.

Will now be at a position of the conveyor belt 10 at the one conductor loop 15 is present, a magnetic signal from the receiver 17 registered, it is concluded from this that this conductor loop 15 at least to the extent intact and undamaged must be that sufficient electromagnetic induction between transmitter 16 and receiver 17 over the contour of the conductor loop 15 can be done. Consequently, no damage to the conveyor belt in this area 10 suspected by a longitudinal slot.

But no magnetic signal from the receiver 17 recorded at this position, so must this conductor loop 15 if damaged or destroyed, there is no adequate electromagnetic induction between the transmitter 16 and receiver 17 over the contour of the conductor loop 15 can be done. This can be done through a longitudinal slot in the conveyor belt 10 be caused.

To generate this electromagnetic interaction are transmitters 16 and receiver 17 from an evaluation unit 13 controlled or monitored. The evaluation unit 13 can also be, for example, the rotational speed U of the drive drum 11 or the reversing drum 12 be fed to the position of the conductor loops 15 to determine. The evaluation unit 13 can send a signal eg to a central unit 14 output to indicate if the respective conductor loops 15 intact and the conveyor belt system 1 can continue to operate or whether a failure of at least one conductor loop 15 was determined and the conveyor belt system 1 for safety reasons. For this purpose, the central unit 14 with the drive drum 11 be connected.

5 shows a schematic sectional view of an electrically conductive structure 20 with insulation 25 which is embedded in the elastomeric material. The electrically conductive structure 20 is in this embodiment, a thread, which of insulation 25 surrounded in the elastomeric material of the conveyor belt 10 to the conductor loop 15 is embedded closed. The insulation 25 is in this embodiment, a plastic coating or a jacket, for example of TPU (thermoplastic polyurethane).

6 shows a schematic sectional view of a connection point 30 an electrically conductive structure 20 , Here are the two ends 21 . 22 of the electrically conductive structure 20 through a splice 30 as a connection point 30 together to form an endless conductor loop 15 connected. The two ends 21 . 22 are not on the insulation 25 surrounded or uncovered by this. The connection point 30 is so from a shrink tube 35 that covers also the ends 21 . 22 of the electrically conductive structure 20 right down to the insulation 25 coated areas of the electrically conductive structure 20 be surrounded by the shrink tube. The shrink tube 35 is in the 6 shown in the unthreaded state; after shrinking, this essentially contracts radially, so that the connection point 30 through the shrunken shrink tubing 35 protected and strengthened. Here is the overlap of the shrink tube 35 and the insulation 25 so chosen that the electrically conductive entity 20 or the closed conductor loop 15 through either the shrunken shrink tubing 35 , the insulation 25 or the overlap thereof included together and against the elastomeric material of the conveyor belt 10 is isolated.

7 shows a perspective schematic sectional view of a conveyor belt 10 with electrically conductive structure 20 with a textile cross reinforcement 28 , This serves to reinforce the conductor loop 15 against application and is between the conductor loop 15 and the support-side cover plate 10a of the conveyor belt 10 arranged.

8th shows a schematic plan view of a cut conveyor belt 10 with two conductor loops 15a . 15b with each other diagonally opposite joints 30a . 30b , The conductor loops 15a . 15b run, as in 3 represented, concentric meandering in the plane of the conveyor belt 10 , In the middle of the conveyor belt 10 is the Gutbeaufschlagungsbereich G provided. Outside the Gutbeaufschlagungsbereichs G are the diagonally opposite joints 30a . 30b arranged.

LIST OF REFERENCE NUMBERS

A

Conveying direction of the conveyor belt system 1

d

Distance between two adjacent conductor loops 15

G

Gutbeaufschlagungsposition of the conveyor belt 10

U

Direction of rotation of the drive drum 11

1

conveyor belt system

10

conveyor belt

10a

load-side cover plate of the conveyor belt 10

10b

Running side cover plate of the conveyor belt 10

11

driving drum

12

reversing drum

13

evaluation

14

central processing unit

15

Conductor loop package (s)

15a

first conductor loop

15b

second conductor loop

16

transmitter

17

receiver

18

Reinforcement of the conveyor belt 10

20

electrically conductive structure

21

first end region of a conductor loop

22

second end region of a conductor loop

25

Isolation of the electrically conductive textile fabric

28

textile cross reinforcement

30

junction

30a

Connection point of the first conductor loop 15a

30b

Connection point of the second conductor loops 15b

35

Heat shrink tubing around the junction 30

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102009025848 A1 [0008]

Claims (10)

Conductor loop ( 15 ) completely in one body ( 10a . 10b ), whereby the body ( 10a . 10b ) has a polymeric material with elastic properties, wherein an electrically conductive structure ( 20 ) after its endless closure the conductor loop ( 15 ), characterized in that the conductor loop ( 15 ) of insulation ( 25 ) surrounded in the body ( 10a . 10b ) is embedded. Conductor loop ( 15 ) according to claim 1, wherein the insulation ( 25 ) has a coating or sheath. Conductor loop ( 15 ) according to claim 1 or 2, wherein the insulation ( 25 ) has an elastomeric tube or shrink tubing. Conductor loop ( 15 ) according to one of the preceding claims, wherein the endless closure of the conductor loop ( 15 ) at the junction ( 30 ) takes place by splicing and / or clamping. Conductor loop ( 15 ) according to claim 4, wherein at least the connection point ( 30 ) of the endlessly closed conductor loop ( 15 ) of at least one shrunken shrink tubing ( 35 ) is surrounded. Conductor loop ( 15 ) according to one of the preceding claims, wherein the conductor loop ( 15 ) a textile cross reinforcement ( 28 ) having. Conveyor belt ( 10 ), with a body ( 10a . 10b ) comprising a polymeric material having elastic properties, a strength member ( 18 ) in the body ( 10a . 10b ), and at least one conductor loop ( 15 ) according to one of claims 1 to 6, which is completely in the body ( 10a . 10b ) is embedded. Conveyor belt ( 10 ) according to claim 7, wherein the body ( 10a . 10b ) a support-side cover plate ( 10a ) and / or a running side cover plate ( 10b ) of the conveyor belt ( 10 ), into which at least one conductor loop ( 15 ) is embedded. Conveyor belt ( 10 ) according to claim 7 or 8, wherein the connection point ( 30 ) of the conductor loop ( 15 ) outside the Gutbeaufschlagungsbereiches (G) of the conveyor belt ( 10 ) is arranged. Conveyor belt ( 10 ) according to one of claims 7 to 9, wherein a first connection point ( 30a ) of a first conductor loop ( 15a ) and a second connection point ( 30b ) a second conductor loops ( 15b ) diagonally across the conductor loops ( 15a . 15b ) enclosed surface in the plane of the conveying direction A opposite.

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