HK1011391B - 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 of artificial fibre rails for lifts.

The failure occurs due to the combination of the different stresses in the lifting ropes, low tensions, but high pressures at high play rates. In normal lifting construction, we speak of a controllable rope failure. This means that the residual useful life can be determined from the degree of external destruction of the wire. The number of wire breaks and the number of the number of pre-breaking wire breaks correspondingly produces a considerable amount of residual power.

The method described above for determining the maturity of the artificial fibre rope cannot be used to assess the possible wear state of an artificial fibre rope, because the outer shell of the new type of supporting organ prevents the visual detection of fibre or strand fractures.

GB-PS 2 152 088 introduces a synthetic fibre rail in which one or more electrically conductive indicator fibres are inserted into the strips to monitor the condition of the rope. The coal indicator fibres surrounded by the synthetic fibres and the line shall have the same mechanical properties so that they fail at the same time. A voltage source can be attached to the indicator fibre to detect a crack in the fibre. This allows each individual stripe of a synthetic fibre rail to be checked and the rope to be replaced if a certain number of strips are broken.

In the above-described invention, the indicator fibers are sized so that they tear simultaneously with the supporting ribbons. In the extreme case, it is therefore difficult to obtain sufficient residual breaking force, since the tear of an indicator fiber means the failure of an entire supporting ribbon and not only of a single fiber of a ribbon. The time span between an apparently intact rope and a necessary replacement of the rope is very small due to this method. The wear progression is therefore not detectable. This device cannot meet the safety requirements in the lift.

The purpose of the invention is to propose a method of detecting the age of deposition of a fibre-reinforced rail for lifts of the type described above, which does not have the abovementioned disadvantages and which enables the replacement of the ropes to be reliably carried out in good time but not unnecessarily prematurely.

This problem is solved by the invention described in claim 1.

The advantages of the invention are essentially shown by the fact that the different characteristics of the conductive indicator fibres and the supporting fibres allow an accurate assessment of the residual breaking strength of the artificial fibre wire.

The measures listed in the subclauses allow for beneficial training and improvements in the deposition detection of artificial fibre ropes as described in claim 1. Each strip position of the artificial fibre ropes preferably has more than one indicator fibre to avoid any randomness in the assessment of the condition of the ropes. The coal indicator fibres twisted or worn with the fibres into strands can be assigned a colour per location to facilitate connection to a voltage source. Installation of indicators in at least two lines allows for a predictive estimation of the deposition point. Furthermore, an inspection cycle with the indicator fibres in place will automatically check the overlap of the ropes in a specific way. The optical overlap of the ropes can be checked at a specific speed and speed so that the speed of the ropes can be easily adjusted to a specific speed and speed limit.

The drawing shows an example of the invention and a detailed explanation of the following: Fig.1, a schematic representation of a lifting system,Fig.2, 3an artificial fibre rail with indicator fibres,Fig.4a slice of an artificial fibre rail with a coal indicator fibre,Fig.5a contacting of indicator fibres at one end of a rope,Fig.6a switch diagram of the inspection control, andFig.7an artificial fibre rail in cross section with a multi-coloured coat.

Fig.1 shows a schematic representation of a lift system. A cabin 2 in a lift shaft 1 is driven by a drive motor 3 with a drive 4 via an artificial fibre rail 5. At the other end of the cable 5 there is a counterweight 6 as a balancing organ. The attachment of the cable 5 to the cabin 2 and to the counterweight 6 is by means of rope connections 7. The friction between the cable 5 and the drive 4 is dimensioned in such a way that, if a counterweight 6 is placed on a buffer 8, further advancement of the cabin 2 is prevented.

Fig.2 and Fig.3 show a synthetic fibre rail 5 with indicator fibres. The synthetic fibre rail 5 shown, constructed in a counter-clockwise design, is trilayered. A rope coat 12 surrounds an outermost seat position 13. A friction-reducing support coat 15 is placed between a middle seat position 14 and the outermost seat position 13. Then an inner seat position 16 and a rope coat 17 follow. The rope coats 18 are twisted or blurred from individual aramid fibres. Each individual strand 18 is treated with an impregnating agent, e.g. polyurethane solution, to protect the aramid fibres.The other fibre, a carbon fibre 19, has a brittle behaviour, i.e. less good bending ability and a lower tensile strength than the aramid fibres. These values of the carbon indicator fibres 19 can be between 30% and 75% of the values of the aramid fibres, depending on the application. According to the different rope tension in rope 5, carbon indicator fibres 19 are positioned in rope 5 with different tensile strengths.A voltage source can be used to determine the number of cracked coal indicator fibres 19.

Fig. 19 shows a sheet 18 of a synthetic fibre rail 5 with a carbon indicator fibre 19. Both types of fibre, aramid fibres 20 and carbon fibres 19, are arranged in parallel and twisted or blurred together in the production of the strip. The carbon fibre 19 can also be placed exactly in the middle of the sheet 18 or run in a spiral on the mantle line. The carbon fibre 19 should be arranged within the impregnating agent to provide adequate protection against compression and friction. Otherwise, a premature failure of the carbon indicator fibre 19 is to be expected and the original false-fading of the rope 5 is to be expected. In any case, in the course of operation, the number of carbon indicator fibres 19 will be either increased or decreased by a large margin due to a change in the dynamic characteristics of the coal indicator fibre 18, which is usually characterised by a good dynamic change rather than by a change in the dynamic characteristics of the aramid fibre 20.

Fig.5 shows a contact between the coal-indicator fibres 19 at one end of a cable 5. The key to this discovery is the good electrical conductivity of the coal-indicator fibres 19. The indicator fibre 19 is placed in at least two lines 18 in each seating position 13, 14, 16 or in the outermost and innermost seating position 13, 16. In a few cases, even one indicator fibre 19 in each seating position 13, 14, 16 is sufficient.The indicator fibres 19 are removed from the cable assembly from the cable attachment 7 and are always connected in pairs. In cabin 2 the cables are also removed from the cable assembly 7 and the indicator fibres 19 are removed from the cable assembly. There the coal indicator fibres 19 are selected by means of a passage measurement and connected to marked electrical lines. These leads on cabin 2 to an inspection control. To facilitate the connection to the inspection control, layers 13, 14, 16 of different colours are assigned to each layer. In the inspection control all the necessary electronic components are located, allowing a continuous inspection of the artwork.

A low-pass filter TP filters the incoming pulses and directs them to a threshold switch SW. The threshold switch SW compares the measured voltages. If specific limits are exceeded, i.e. due to the moving indicator fibers 19, the resistance is so large that the permissible peak resistance value is exceeded. This excess voltage is stored by a non-volatile spike meter. This meter is then automatically discharged by means of a T-shaped switch or a continuous logarithmic discharge.

In order to ensure a certain residual load capacity of cable 5, only a certain percentage of the indicator fibres 19 must fail. This value can vary, depending on the dimension of the coal indicator fibres 19, between 20% and 80% in relation to all the coal indicator fibres 19. The lift is then driven to a predetermined stop and turned off automatically. Fault messages can be transmitted and displayed via a display. The wear condition can be checked via a modem from anywhere.

This detection also allows the testing of strands 18 located in the middle or innermost strands 14, 16 of the cable 5 without the need for visual assessment or inductive testing. To take into account the different mechanical stress states in the strands 13, 14, 16 in the artificial fibre cable 5, the individual strands 13, 14, 16 are assigned to coal indicator fibres 19 with appropriate break stretch. The outermost indicator fibres 19, which must withstand the highest push loads in addition to the pressures, can be assigned to indicator fibres 19 with a slightly higher break width. This allows optimum control of the cable's break.

Fig.7 shows a cross-sectional fibre rail 5 with a multicolored coating. For the visual assessment of a fibre rail 5 for a possible wear-and-tear condition, the existing coating surface is checked. This must be able to ensure that an abrasion of the coating 12 is produced on the surface. This abrasion is generated over the slip occurring in running operation. The slip represents the measure of the relative movement between the 5th and the 4th drive. It is defined as the difference in the speeds of the 5th and the 4th drive in relation to the slipperiness of the rope.When running over the drive 4 the weights hanging on both sides cause different pulling forces, tensile stresses will occur in any case, even if the pulling capacity is extremely large. The rope 5 has different stresses in front of and behind the drive 4 at different pulling forces. This creates different pulling forces in front of and behind the drive 4. When running over the drive 4 the new pulling state is introduced by sliding the rope 5.

The rope 5 always slides on the drive 4 in the direction of the greater rope pull, regardless of the direction of rotation of the drive 4. The size of the extension loop increases in proportion to the buoyancy of the rope coat 12 and the groove geometry of the drive 4.

The surface of the rope coat 12 can be described as a mountain/valley structure. Due to the material combination of the artificial fibre coat 5 and the cast/steel drive 4 it is no longer subject to abrasive wear, so that in principle it can be called a defined running surface 30. Any fluids on the drive 4 can be displaced from the defined running surface due to the mountain/valley structure of the rope coat 12. The greatest pressures applied to the coated sheets 18 are applied in the groove base 31 of the drive 4 to the ridges 32 of the 5th.The surface wear is caused mainly by the elongation coil, but also to a certain extent by the sliding coil. The experience with steel ropes will show the greatest changes on the acceleration lines. In order to determine the amount of abrasion, i.e. to provide the tester with a means of visually checking whether there is sufficient coat thickness until the next test, the coat of ropes 12 is extruded in an inner 33 and an outer 34 coat. The thickness of the coat of extrusion, i.e. the second 33 coat, measures a specific strength which still provides a sufficient load capacity. The coat of 12 18 lines is protected and produces the necessary traction.If the examiner detects on a visual inspection the extruded second colour 33 of the rope coat 12, he will know that rope 5 must be replaced in the foreseeable future.

For the optimal assessment of the rope condition of a synthetic fibre rope, a combination of the two test methods, the self-monitoring with indicator fibres 19 and the visual rope coat inspection with a two-colour coat, should be used.

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.