EP0731209B1 - Device for detecting the end of service life for synthetic fibre ropes - Google Patents

Description

The invention relates to a device for detecting the Maturity for synthetic fiber ropes for lifts.

Steel cables are still used in elevator construction today, which with the cabins or the load handling devices and Counterweights are connected. These running steel cables are not permanent. Through swelling tensions and supported by the wear occur in the Bending zones gradually break open. The Failure occurs through the combination of different Stress in elevator ropes, low tensile stress, but high pressures with high game numbers. in the Elevator construction is called controllable Rope failure. This means that from the outside Degree of destruction of the rope the safe Remaining service life can be read. From the number of Broken wires and especially on the number of outer ones Broken wires can only partially affect the remaining Rope breaking force must be closed. Internal wire breaks may go unnoticed. Because of that the number of wire breaks by a certain number of Broken wires defined on a section of rope. Of the The inspector counts the number of wire breaks accordingly. If the wire rope is ready to be discarded on the The number of wire breaks recognized in good time usually remains receive a sufficient residual breaking force that the occurring cable pulling force exceeds.

In this respect, a synthetic fiber rope is not a steel rope to compare. Due to the synthetic fiber rope style the method described above for determining the Discard maturity not for the assessment of a possible Wear condition of a synthetic fiber rope used become. The outer jacket of the new support element prevents the visual detection of fiber or Strand breaks.

With GB-PS 2 152 088 is a synthetic fiber rope become known in which one or more electrically conductive indicator fibers are inserted into the strands, to monitor the rope condition. The synthetic fibers Surrounded carbon indicator fibers and the braid are said to have the same mechanical properties so that they fail at the same time. By creating one Voltage source on the indicator fiber can tear of the fiber can be detected. In this way, everyone single strand of a synthetic fiber rope checked and attached Exceeding a certain number of torn strands Rope to be replaced.

In the invention described above, the Indicator fibers dimensioned so that they are simultaneously tear with the carrying strands. So in the extreme case it is difficult to obtain sufficient residual breaking strength because the tear of an indicator fiber is the failure of one entire stranded wire means and not just one single fiber of a strand. The period between an apparently intact rope and a necessary one Changing the rope is very much due to this method small. The wear progress is therefore not recognizable. This facility can Safety requirements in elevator construction are not sufficient. Furthermore, the diameter is reduced Synthetic fiber rope, or wear of the sheath, too optically not after a large number of bending changes detect.

The invention has for its object a Discard maturity detection for a synthetic fiber rope for lifts of the type mentioned at the beginning, which the does not have the aforementioned disadvantages and by means of which a replacement of the ropes reliably in time, but cannot be done prematurely unnecessarily.

This object is achieved by the in claim 1 characterized invention solved.

The advantages achieved by the invention are in essential to see that through different Properties of the conductive indicator fibers and the bearing fibers an accurate assessment of the Residual breaking strength of the synthetic fiber rope is possible.

By the measures listed in the subclaims are advantageous developments and improvements of discard maturity detection for Synthetic fiber ropes possible. Every strand of the Synthetic fiber rope preferably has more than one Indicator fiber, so a randomness in the Assessment of the condition of the rope is excluded. The one with the fiber twisted or twisted carbon indicator fibers can be assigned one color per layer are to be connected to a voltage source simplify. Indicator fibers in at least everyone Strand position enables a predictive assessment the time of filing. By means of a Indicator fibers related Inspection control takes place at certain intervals the rope is checked automatically. At a The elevator automatically closes when the limit value is exceeded drove to a certain stop and switched off. In addition, the rope can be covered with a two-layer different colored rope sheath can be equipped so that the degree of wear of the rope in a simple way can be checked visually.

Fig.1

eine schematische Darstellung einer Aufzugsanlage,

Fig.2, 3

ein Kunstfaserseil mit Indikatorfasern,

Fig.4

eine Litze eines Kunstfaserseils mit einer Kohle-Indikatorfaser,

Fig.5

eine Kontaktierung von Indikatorfasern an einem Seilende,

Fig.6

ein Schaltschema der Inspektionssteuerung, und

Fig.7

ein Kunstfaserseil im Querschnitt mit mehrfarbigem Mantel.

In the drawing, an embodiment of the invention is shown and explained in more detail below. Show it:

Fig. 1

1 shows a schematic representation of an elevator installation,

Fig. 2, 3

a synthetic fiber rope with indicator fibers,

Fig. 4

a strand of a synthetic fiber rope with a carbon indicator fiber,

Fig. 5

contacting of indicator fibers at one end of the rope,

Fig. 6

a circuit diagram of the inspection control, and

Fig. 7

a cross section of a synthetic fiber rope with a multicolored sheath.

1 shows a schematic representation of a Elevator system. One guided in an elevator shaft 1 Cabin 2 is powered by a drive motor 3 Traction sheave 4 driven by a synthetic fiber rope 5. At the other end of the rope 5 hangs a counterweight 6 as Compensation body. The attachment of the rope 5 to the Cabin 2 and on counterweight 6 takes place over Rope end connections 7. The coefficient of friction between the rope 5 and the traction sheave 4 is dimensioned so that at a counterweight 6 placed on a buffer 8 further promotion of the cabin 2 is prevented.

2 and 3 show a synthetic fiber rope 5 with Indicator fibers. The shown, in counterblow execution assembled synthetic fiber rope 5 is three layers. A Rope sheath 12 surrounds an outermost strand layer 13. Between a middle strand layer 14 and the outermost one Strand layer 13 becomes a friction-reducing support jacket 15 appropriate. Then an inner strand layer 16 and a rope core 17. The strands 18 are made of individual Aramid fibers twisted or twisted. Every single strand 18 is used to protect the aramid fibers with a Impregnating agents, e.g. Treated polyurethane solution. The The principle of discard maturity is based on the Merging two types of fibers with different ones Properties to a strand 18. The one fiber, the Aramid, has a high ability to change bends and a high specific elongation. The other fiber, one Carbon fiber 19 has a more brittle behavior, i.e. one less good bending ability and a lower one Elongation at break than the aramid fibers. These values of the carbon indicator fibers 19 can be 30% - 75% depending on the application the values of aramid fibers. According to the im Rope 5 occurring different cable tension are carbon indicator fibers 19 with different Elongation at break positioned in rope 5. Due to the Seilmachart takes the strand length to the core 17 of the rope 5 down, so that the inner strands during operation will have the least stretch. The stretch Accordingly, 19 become conductive for the indicators Fibers with decreasing towards the rope core 17 Elongation at break used. With the help of a voltage source the number of broken carbon indicator fibers 19 be determined.

4 shows a strand 18 of a synthetic fiber rope 5 with a carbon indicator fiber 19. Both types of fibers, Aramid fibers 20 and carbon fiber 19 are used in the Strand production arranged in parallel and with each other twisted or twisted. The carbon fiber 19 also be placed exactly in the middle of the strand 18, or run helically on the surface line. The Carbon fiber 19 should be within the impregnating agent be arranged to provide adequate protection against Pressure and friction is given. Otherwise, is a premature failure of the carbon indicator fiber 19 too expect and the rope 5 appears incorrectly ready for discard. In ongoing operation, the Carbon indicator fiber 19 either due to too large Stretching or too many bending cycles more likely to tear or break than the aramid fibers 20 one Strand 18, which is characterized by exceptionally good characterized dynamic properties.

5 shows a contacting of the carbon indicator fibers 19 at one end of a rope 5. Crucial for this maturity detection is the good electrical one Conductivity of the carbon indicator fibers 19. The Indicator fiber 19 is in each strand layer 13, 14, 16 or in the outermost and innermost strand layer 13, 16 placed in at least two strands 18. In a few cases only one indicator fiber 19 is sufficient in each Strand layers 13, 14, 16 from. With 1: 1 suspended lifts are always two indicator fibers 19 of a strand 13, 14, 16 on the counterweight 6 by connecting elements 22 connected together or connected in series. At This process can be hung in 2: 1 attachments Engine room to be carried out. The indicator fibers 19 are from the composite of the rope end attachment 7th led out rope end and always in pairs connected with each other. On the cabin 2 Rope ends also from the rope end connection 7 led out and the indicator fibers 19 from the Rope assembly released. There they belong together Carbon indicator fibers 19 by means of continuity measurement picked out and marked with electrical Lines connected. These lines run on the Cabin 2 in an inspection control. To the connection to simplify inspection control will individual strands 13, 14, 16 different colors assigned. In the inspection control are all necessary electronic components, one enable constant testing of the synthetic fiber rope 5.

Fig. 6 shows a circuit diagram of the inspection control. A constant current Ik into the indicator fiber 19 running towards the counterweight 6 fed. The carbon indicator fiber 19 represents one Resistor R. A low-pass filter TP filters the incoming impulses and leads them to you Threshold switch SW closed. The SW threshold switch compares the measured voltages. If exceeded specific limit values, i.e. due to the tearing The indicator fibers 19 the resistance becomes so great that the permissible voltage value is exceeded. This One does not exceed the limit volatile memory M stored. This memory M can be deleted by means of a reset button T or there his information to someone on the cabin 2 Logic L further. This logic L is from the Elevator control queried automatically. Each Indicator pairing is made according to the above Arrangement wired and constantly checked. The Elevator control continuously checks the logic and switches the elevator off if too many fiber tears from the logic be transmitted.

So that a certain residual load capacity of the rope 5 only a certain one can be guaranteed Percentage of indicator fibers 19 fail. This value can, depending on the dimensioning of the carbon indicator fibers 19, are between 20% and 80% on all carbon indicator fibers 19. Then the elevator automatically moved into a predetermined stop and switched off. Malfunction reports can be made on a display passed on and displayed. Of the Wear status can be checked by anyone via a modem can be queried from any location.

This maturity detection also enables testing of strands 18 that are in the middle or innermost Strand layer 14, 16 of the rope 5 are arranged without the a visual assessment or an inductive test would be necessary. So that the different mechanical Tension states in the strand layers 13, 14, 16 in Synthetic fiber rope 5 can be taken into account the individual layers 13, 14, 16 carbon indicator fibers 19 associated with corresponding elongations at break. The outermost indicator fibers 19 in addition to the pressings can withstand the highest shear loads Indicator fibers 19 with a somewhat higher elongation at break be assigned. In this way, an optimal controlled rope wear control can be guaranteed.

7 shows a synthetic fiber rope 5 in cross section, with multicolored coat. For the visual assessment of a Synthetic fiber rope 5 to a possible tire The existing condition becomes worn Rope jacket surface checked. This must be guaranteed can be that an abrasion of the cable sheath 12 on the Surface takes place. This abrasion is over the in slip occurring during operation. Of the Slip sets the measure for the relative movement between Rope 5 and traction sheave 4. It is defined as the Difference in speeds of rope 5 and Traction sheave 4 based on the rope speed. Has a rope 5 when running onto the traction sheave 4 is not their speed, one speaks of sliding slip. If when running over the traction sheave 4 on both sides hanging weights different cable tensile forces cause expansion slip will occur in any case, even if the driving ability were extremely high. The rope 5 has different pulling forces in front and behind the traction sheave 4 different voltages. Thereby are different strains in front of and behind the Traction sheave 4 generated. When running over the traction sheave 4 the new state of stretching arises when the Rope 5 a. With a small rope force ratio, the resulting sliding movement in the area of the Point of expiry on, with fully exhausted driving ability on the other hand, there is a slide across the entire Wrap on.

The rope 5 always slides on the traction sheave 4 in Direction of the greater rope pull, regardless of the Direction of rotation of the traction sheave 4. The order of magnitude of the Elongation slip increases according to the driving ability of the Rope sheath 12 and the groove geometry of the traction sheave 4th

The cable sheath 12 should be one of the strand structure get appropriate surface. The surface of the Rope sheath 12 can be referred to as a mountain / valley structure become. Due to the material combination of the Synthetic fiber rope 5 and the cast / steel drive pulley 4 this is no longer subject to abrasive wear, so that in principle from a defined tread 30 can be spoken. Any liquids on the Traction sheave 4 can due to the mountain / valley structure Rope sheath 12 displaced from the defined tread become. The largest pressings on the jacketed Strands 18 act in the groove base 31 of the Traction sheave 4 on the mountain areas 32 of the rope 5 exercised. As a result, the largest are there Signs of wear can be recognized. Especially due to the expansion slip, but also to a certain extent due to the slip, the surface wear generated. Experience with the steel cables turns them into biggest changes on the acceleration routes be recorded. So the amount of abrasion determined, i.e. the auditor a means of visual Control can be made available up to the next test, there is sufficient sheath thickness the cable sheath 12 in an inner 33 and an outer Color 34 extruded. The thickness of the inner rope extrusion, i.e. the second color 33 measures a specific strength, which still guarantees a sufficiently large running ability. The jacket 12 protects the strands 18 and generates the necessary traction ability. The examiner recognizes at a visual inspection the extruded second color 33 of the rope sheath 12, he knows that the rope 5 in foreseeable future needs to be replaced.

For optimal assessment of the rope condition of a Synthetic fiber rope should be a combination of the two Test methods, self-control by means of Indicator fibers 19 and the visual rope sheath control with a two-tone coat.

Claims (10)

1. Equipment for recognising when synthetic fibre cables (5) for lifts are ripe for being discarded, wherein the synthetic fibre cable (5) is built up of several strand layers (13, 14, 16) and its strands (18) consist of aramide fibres (20) and electrically conductive carbon indicator fibres (19), characterised thereby, that the carbon indicator fibres (19) are dimensioned for a lower specific expansion and a lower bending fatigue strength than the aramide fibres (20).
2. Equipment according to claim 1, characterised thereby, that the breaking elongations of the carbon indicator fibres (19) become smaller towards the cable core (17).
3. Equipment according to one of the claims 1 and 2, characterised thereby, that each strand layer (13, 14, 16) displays at least one carbon indicator fibre (19).
4. Equipment according to one of the claims 1 to 3, characterised thereby, that the carbon indicator fibres (19) are twisted or turned together with the aramide fibres (20) out of a parallel arrangement.
5. Equipment according to one of the claims 1 to 4, characterised thereby, that the carbon indicator fibres (19) extend centrally in the strands (18).
6. Equipment according to one of the claims 1 to 4, characterised thereby, that the carbon indicator fibres (19) extend helically on the surface of a strand (18).
7. Equipment according to one of the claims 1 to 6, characterised thereby, that the lift control automatically interrogates the state of the cable (5) or strands (18) from a logic system (L).
8. Equipment according to one of the claims 1 to 7, characterised thereby, that different colours are allocated to the individual strand layers (13, 14, 16).
9. Equipment according to one of the claims 1 to 8, characterised thereby, that a cable sheath (12) of the synthetic fibre cable (5) displays an inner sheath colour (33) and an outer sheath colour (34).
10. Equipment according to claim 9, characterised thereby, that the thickness of the cable seath (12) in the region of the inner sheath colour (33) guarantees a sufficiently great running capacity.

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