Patent Application
20120329591
The present invention relates to a belt for drive engineering, composed at least of:
Belts of this type are also termed force-transmission belts and can be flat belts, V-belts, V ribbed belts or toothed belts, or composite cables. In this connection, reference is particularly made to the following patent literature: DE 38 23 157 A1, U.S. Pat. No. 7,128,674, United States patent application publication 2008/0261739, DE 10 2007 062 285 A1, DE 10 2008 012 044 A1, U.S. Pat. No. 7,749,118 and United States patent application publication 2010/0240481, United States patent application publication 2008/0032837, U.S. Pat. No. 3,981,206, U.S. Pat. No. 5,417,618, and U.S. Pat. No. 6,491,598.
The elasticity of a belt is achieved in that the belt structure, and therefore the outer layer and the substructure, is/are composed of a polymeric material with elastic properties, and two groups of materials that may be mentioned in particular here are elastomers and thermoplastic elastomers. Elastomers based on a vulcanized rubber mixture comprising at least one rubber component and mixture ingredients are particularly important. The following are in particular used as rubber component: ethylene-propylene rubber (EPM), ethylene-propylene-diene rubber (EPDM), (partially) hydrogenated nitrile rubber (HNBR), fluoro rubber (FKM), natural rubber (NR), chloroprene rubber (CR), styrene-butadiene rubber (SBR), butadiene rubber (BR) or polyurethane (PU), and these may be unblended or blended with at least one further rubber component, in particular with one of the abovementioned types of rubber, for example in the form of an EPM/EPDM blend or SBR/BR blend. A particularly important material here is HNBR, EPM, EPDM, PU or an EPM/EPDM blend. The mixture ingredients encompass at least one crosslinking agent or one crosslinking agent system (crosslinking agent and accelerator). Further additional mixture ingredients are mostly a filler and/or a processing aid and/or a plasticizer and/or an antioxidant and optionally other additional materials, for example fibers for reinforcement purposes, and color pigments. In this connection, reference is made to the general prior art of rubber mixture technology.
The belt has an embedded tension-member system, formed from at least one tension member running in the longitudinal direction of the belt. A plurality of tension members mostly form a tension-member-system layer. Particular importance is attached here to a tension member which has a cord structure, and in this connection various materials are used in designs of the prior art. The significant types of material are: steel, polyamide (PA), aramid, polyester, glass fibers, carbon fibers, basalt, polyether ether ketone (PEEK), polyethylene terephthalate (PET), polybenzoxazole (PBO) and polyethylene-2,6-naphthalate (PEN). The preparation of the tension member moreover mostly uses an adhesive system, for example a resorcinol-formaldehyde latex (RFL), in order to provide long-term adhesion to the surrounding polymeric material.
Steel has now become a relatively unimportant material in continuous belts for vehicle construction. Tension members in particular used here are made of PA or PET or else in recent times of basalt.
However, when noncontinuous belts are used as tension element in elevator engineering—which is a central topic hereinafter—the high tensile force gives significant importance to steel as tension-member material, in particular in the form of steel cords. In relation to the prior art in this connection, reference is particularly made to the following patent literature: DE 10 2006 020 633 B3, DE 10 2008 018 191 A1, DE 10 2008 018 192 A1, DE 10 2008 037 537 A1, United States patent application publication 2011/0226562, EP 1 396 458 A2, U.S. Pat. No. 7,757,817 and United States patent application publication 2009/0166132, United States patent application publication 2002/0000346, and U.S. Pat. No. 6,739,433.
In particular the force-transmission zone of a belt is provided with an abrasion-resistant coating which also serves for noise reduction and can moreover have been rendered oil-resistant. Materials used here are a superposed flock, in particular taking the form of a cotton flock or aramid flock, a thin elastic polymer layer filled with fibers (for example, aramid fibers), a superposed textile, in particular taking the form of a woven or knitted material, or a foil (for example, PTFE foil) or a foil composition (for example, PA-PTFE foil). The woven material is particularly important here. The coatings mentioned here are mostly prepared in a manner that promotes adhesion on the side of contact with the belt structure, in particular with the substructure thereof, an example of a material used for this purpose being RFL.
A problem with belts of all types is that the polymeric material of the belt structure is very combustible. In the event of a fire, the entire belt-structure material would be consumed by combustion and sometimes also damage the tension-member system. These problems are particularly relevant to a belt-like tension element for elevator engineering, where the steel tension-element system can then be damaged. In any event, the elevator would no longer function correctly and would therefore no longer be safe.
The object of the invention then consists in providing a belt, in particular a tension element for elevator engineering, where the belt-structure material is intended to be non-combustible or self-extinguishing, in such a way that a fire does not affect the entire belt, in particular the entire tension element, and specifically capability to function correctly is retained, in particular in the case of elevator systems.
The object is achieved in that the belt structure is composed of at least two different materials A and B, namely of:
In particular in the case of the first material A, the mixture ingredients mentioned in the introduction for the polymeric material are supplemented by the fire-retardant additive.
The quantitative proportions applicable to the first material A and the second material B within the belt structure are preferably as follows:
The following classes of substance are in particular used as fire-retardant additives:
It is possible here to use a single class of substance, for example a melamine phosphate, or a two- or multicomponent system, for example a mixture of melamine phosphate and melamine cyanurate.
The additives here have been mixed in essence uniformly within the polymer matrix, in particular in the case of the first material A.
The quantitative proportion of the fire-retardant additive for the first material A is preferably from 5% by weight to 50% by weight, in particular from 10% by weight to 30% by weight.
The quantitative proportion of the fire-retardant additive for the second material B is in contrast preferably from 0% by weight to 5% by weight, in particular from 0 to 3% by weight. The focus of the fire-retardant properties is therefore exclusively on the first material A.
The outer layer of the belt, where there is no requirement for the high level of mechanical properties, comprises the first material A with its fire-retardant properties.
The substructure with its force-transmission zone, which is in contact with the traction pulley, is subject to the highest level of mechanical requirements, and in contrast the second material B, with no, or only a low level of, fire-retardant properties is therefore used here. The second material advantageously comprises no fire-retardant additives, since admixture of additives of this type can adversely affect the mechanical property profile of the polymeric material.
The tension-member-system region which also forms the transition region of outer layer and substructure can be in contact with the first material A and/or second material B, and in particular the following two variants are used here:
In another possible design, the first material A forms the belt core and the second material B forms the belt shell. In particular here, the tension-member system has been embedded in the belt core with complete sheathing by the first material A. The immediate environment of the tension-member system is thus involved in the fire-retardant properties. It is preferable that the belt shell with the second material B completely surrounds the belt core. A design using this type of material is presented in more detail in conjunction with the example in
It is mostly sufficient that the belt structure is composed exclusively of the two materials A and B, in particular in conjunction with the two abovementioned variants.
It can be advantageous, if the belt type and the position of the tension-member system are appropriate, to equip the belt structure additionally with an elastic intermediate layer with a third material C, where the tension-member system has been embedded within the intermediate layer. There can be a fire-retardant additive mixed into the intermediate layer, and reference is made here to the following example:
The concentration of the fire-retardant additive rises in the belt structure from the substructure, which is free from any fire-retardant additive, toward the outer layer.
The belt structure can additionally have at least one embedded layer. The layer is in particular composed of a textile material in the form of a woven or knitted material. The layer can also have been rendered fire-retardant in that by way of example the textile fibers have been prepared so as to be fire-retardant.
The outer layer and/or the force-transmission zone can equally additionally have a coating. A particular coating used is a superposed textile in the form of a woven or knitted material. The superposed woven material is particularly important here. The coating can likewise have been rendered fire-retardant, again in that by way of example the textile fibers have been prepared so as to be fire-retardant.
The belt is a flat belt, V-belt, V-ribbed belt or toothed belt, or as composite cable.
The belt of the invention is in particular used as tension element in elevator engineering, in particular with use of composite cables, or of a flat belt or toothed belt. In the event of a fire, the fire is not distributed by way of the tension element through the height of the entire elevator shaft. The tension element comprising these materials has very low flammability and mostly self-extinguishes after the fire has made very little progress.
The elevator retains some capability to function. Another advantage is that a tension element of this type cannot transmit a fire in a building from one storey to the next.
The invention will now be described with reference to the drawings wherein:
The outer layer 2 and the substructure 4 form, as entire unit, the elastic belt structure which is also termed main structure, for example based on PU. The belt structure here is based on a first material A and a second material B. The first material A with a high proportion of a fire-retardant additive (for example, 25% by weight) here encompasses the entire outer layer 2, where there is no requirement for the high level of mechanical properties. The second material B, which has low (for example, 3% by weight), or no, content of a fire-retardant additive encompasses almost the entire substructure 4 with the force-transmission zone 7. That is where the belt structure is subject to the greatest mechanical load. The second material B here has been arranged within a rib 5 of the substructure 4, and at the same time almost sheaths the entire tension-member system 3.
The outer layer 10 and the substructure 12 here likewise form, as entire unit, the elastic belt structure, for example again based on PU. The belt structure here is composed of a first material A and a second material B. The first material A with a high proportion of a fire-retardant additive (for example, 25% by weight) here encompasses the entire outer layer 10 and the entire region of the tension-member system 11 which means that the first material A here completely sheaths all of the steel cords. The substructure 12 with the flat force-transmission zone 13 comprises the second material B, which has low (for example, 3% by weight), or no, content of a fire-retardant additive.
In respect of the traction pulley, reference is made to the examples in
It is understood that the foregoing description is that of the preferred embodiments of the invention and that various changes and modifications may be made thereto without departing from the spirit and scope of the invention as defined in the appended claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2010 016 872.6 | May 2010 | DE | national |
This application is a continuation application of international patent application PCT/EP 2010/063776, filed Sep. 20, 2010, designating the United States and claiming priority from German application 10 2010 016 872.6, filed May 11, 2010, and the entire content of both applications is incorporated herein by reference.
| Number | Date | Country | |
|---|---|---|---|
| Parent | PCT/EP2010/063776 | Sep 2010 | US |
| Child | 13605697 | US |
