Patent Description:
Elevator systems utilize a lifting means, such as ropes or belts operably connected to an elevator car, and routed over one or more sheaves, also known as pulleys, to propel the elevator along a hoistway. Lifting belts in particular typically include a plurality of wires at least partially within a jacket material. The plurality of wires are often arranged into one or more strands and the strands are then arranged into one or more cords.

Lifting belts may be required to meet certain established standards to be certified for fire resistance, and/or may require the installation of fire mitigation systems. Thus, the jacket material is often formed of a material with increased fire resistant properties at the outer surface of the belt. Such materials, however, can have non-optimal wear durability and other mechanical performance characteristics.

<CIT> discloses a steel-cored wire rope which is resistant to high temperatures and aging. <CIT> discloses a belt for driving technology consisting of two polymeric materials with elastic properties, comprising a cover layer as a belt back, a substructure with a force transmission zone and a tension member embedded in the belt body. <CIT> discloses a hoist rope for an elevator made from synthetic, non-metallic materials.

In one embodiment, a belt for suspending and/or driving an elevator car of an elevator system includes a plurality of tension members arranged in a lengthwise direction and a jacket substantially retaining the plurality of tension members. The jacket includes a traction portion, a back portion, and an inner portion between the traction portion and the back portion. The traction portion is formed from a first material and the inner portion is formed from a second material having an increased fire resistance compared to the first material. The belt further comprises an edge treatment at one or more lateral edges of the belt to increase fire resistance of the lateral edges. The edge treatment has a C-shaped cross-section and mechanically interlocks with the j acket.

Additionally, in alternative embodiments of the belt one or more intermediate layers are located between the traction portion and the inner portion, and/or between the inner portion and the back portion.

Additionally, in alternative embodiments of the belt the one or more intermediate layers are formed from a fiberglass fabric, another fire-resistant fabric, or a wire metal mesh.

Additionally, in alternative embodiments of the belt the back portion has increased fire resistance relative to the traction portion.

Additionally, in alternative embodiments of the belt the traction portion and the back portion are formed from the same material.

Additionally, in alternative embodiments of the belt the edge treatment includes a layer of material located at one or more lateral edges of the belt having increased fire resistance relative to the traction portion.

Additionally, in alternative embodiments of the belt the layer of material is formed from the second material.

Additionally, in alternative embodiments of the belt the edge treatment extends in board partially along the traction portion and/or the back portion.

Additionally, in alternative embodiments of the belt the edge treatment includes an at least partially exposed tension member.

Additionally, in alternative embodiments of the belt the tension member is one of a cord formed from a plurality of metal wires, or metallic strips located at the edge portion.

Additionally, in alternative embodiments of the belt, the edge treatment is preformed and secured to the jacket during formation of the jacket.

In another embodiment, an elevator system includes an elevator car movable along a hoistway, a machine located in the hoistway to drive rotation of a traction sheave, and a belt as herein described operably connected to the elevator car and interactive with the traction sheave such that rotation of the traction sheave drives movement of the elevator car along the hoistway.

Additionally, in alternative embodiments of the elevator system one or more intermediate layers are located between the traction portion and the inner portion, and/or between the inner portion and the back portion.

Additionally, in alternative embodiments of the elevator system the one or more intermediate layers are formed from a fiberglass fabric, another fire-resistant fabric, or a wire metal mesh.

Additionally, in alternative embodiments of the elevator system the back portion has increased fire resistance relative to the traction portion.

Additionally, in alternative embodiments of the elevator system the back portion and the traction portion are formed from the same material.

Additionally, in alternative embodiments of the elevator system the edge treatment comprises a layer of material having increased fire resistance relative to the traction and/or back portions.

Additionally, in alternative embodiments of the elevator system the layer of material is formed from the second material.

Additionally, in alternative embodiments of the elevator system the edge treatment extends partially along the traction portion.

Additionally, in alternative embodiments of the elevator system the edge treatment includes an at least partially exposed tension member.

In yet another embodiment, a method of forming an elevator system belt (e.g. a belt as herein described) includes arranging a plurality of tension members in a lengthwise direction and securing the plurality of tension members in a jacket by at least partially enclosing the plurality of tension members in the jacket. The jacket includes a traction portion, a back portion, and an inner portion having a greater fire resistance than the traction portion. The belt further comprises an edge treatment at one or more lateral edges of the belt to increase fire resistance of the lateral edges. The edge treatment is preformed and secured to the jacket during formation of the jacket.

Additionally, in alternative embodiments of the method the jacket is trimmed to expose the inner portion at a lateral edge of the jacket thus forming an edge treatment having an increased fire resistance.

Additionally, in alternative embodiments of the method one or more fire retardant edge portions are formed, and the one or more edge portions are secured to one or more lateral edges of the jacket.

Additionally, in alternative embodiments of the method the one or more edge portions are preformed, and the one or more edge portions are guided into a forming tool together with the plurality of tension members. The plurality of tension members are at least partially enclosed in the jacket at the forming tool, and the one or more preformed edge portions are secured to the jacket at the forming tool.

The subject matter, which is regarded as the invention, is particularly pointed out and distinctly claimed in the claims at the conclusion of the specification. The foregoing and other features, and advantages of the invention are apparent from the following detailed description taken in conjunction with the accompanying drawings in which:.

Shown in <FIG>, <FIG> and <FIG> are schematics of exemplary traction elevator systems <NUM>. Features of the elevator system <NUM> that are not required for an understanding of the present invention (such as the guide rails, safeties, etc.) are not discussed herein. The elevator system <NUM> includes an elevator car <NUM> operatively suspended or supported in a hoistway <NUM> with one or more belts <NUM>. The one or more belts <NUM> interact with one or more sheaves <NUM> to be routed around various components of the elevator system <NUM>. The one or more belts <NUM> could also be connected to a counterweight <NUM>, which is used to help balance the elevator system <NUM> and reduce the difference in belt tension on both sides of the traction sheave during operation.

The sheaves <NUM> each have a diameter <NUM>, which may be the same or different than the diameters of the other sheaves <NUM> in the elevator system <NUM>. At least one of the sheaves could be a drive sheave <NUM>. The drive sheave <NUM> is driven by a machine <NUM>. Movement of the drive sheave <NUM> by the machine <NUM> drives, moves and/or propels (through traction) the one or more belts <NUM> that are routed around the drive sheave <NUM>.

At least one of the sheaves <NUM> could be a diverter, deflector or idler sheave <NUM>. Diverter, deflector or idler sheaves <NUM> are not driven by the machine <NUM>, but help guide the one or more belts <NUM> around the various components of the elevator system <NUM>.

In some embodiments, the elevator system <NUM> could use two or more belts <NUM> for suspending and/or driving the elevator car <NUM>. In addition, the elevator system <NUM> could have various configurations such that either both sides of the one or more belts <NUM> engage the one or more sheaves <NUM> (such as shown in the exemplary elevator systems in <FIG>, <FIG> or <FIG>) or only one side of the one or more belts <NUM> engages the one or more sheaves <NUM>.

<FIG> provides a <NUM>:<NUM> roping arrangement in which the one or more belts <NUM> terminate at the car <NUM> and counterweight <NUM>. <FIG> and <FIG> provide different roping arrangements. Specifically, <FIG> and <FIG> show that the car <NUM> and/or the counterweight <NUM> can have one or more sheaves <NUM> thereon engaging the one or more belts <NUM> and the one or more belts <NUM> can terminate elsewhere, typically at a structure within the hoistway <NUM> (such as for a machineroomless elevator system) or within the machine room (for elevator systems utilizing a machine room). The number of sheaves <NUM> used in the arrangement determines the specific roping ratio (e.g. the <NUM>:<NUM> roping ratio shown in <FIG> and <FIG> or a different ratio). One skilled in the art will readily appreciate that the configurations of the present disclosure could be used on elevator systems other than the exemplary types shown in <FIG>, <FIG> and <FIG>.

Referring to <FIG>, a cross-sectional view of an exemplary belt <NUM> is shown. The belt <NUM> is constructed of one or more cords <NUM> in a jacket <NUM>. The cords <NUM> of the belt <NUM> may all be identical, or some or all of the cords <NUM> used in the belt <NUM> could be different than the other cords <NUM>. For example, one or more of the cords <NUM> could have a different construction, formed from different materials, or size than the other cords <NUM>. As seen in <FIG>, the belt <NUM> has an aspect ratio greater than one (i.e. belt width is greater than belt thickness). Each cord <NUM> comprises a plurality of wires <NUM>, which in some embodiments are formed into strands <NUM>, which are then formed into the cord <NUM>.

The belt <NUM> is constructed to have sufficient flexibility when passing over the one or more sheaves <NUM> to provide low bending stresses, meet belt life requirements and have smooth operation, while being sufficiently strong to be capable of meeting strength requirements for suspending and/or driving the elevator car <NUM>.

The jacket <NUM> includes a traction portion <NUM> interactive with and contacting the drive sheave <NUM> and a back portion <NUM> opposite the traction portion <NUM>. Further, a width of the belt <NUM> is defined by edge portions <NUM>. An inner portion <NUM> of the belt <NUM> may be located between the traction portion <NUM> and the back portion <NUM>. The traction portion <NUM> and back portion <NUM> each have thicknesses extending across a thickness of the belt <NUM> so that the desired materials of the traction portion <NUM> and back portion <NUM> are present at these locations over a service life of the belt <NUM>.

The jacket <NUM>, for example, inner portion <NUM>, can substantially retain the cords <NUM> therein. The phrase substantially retain means that the jacket <NUM> has sufficient engagement with the cords <NUM> such that the cords <NUM> do not pull out of, detach from, and/or cut through the jacket <NUM> during the application on the belt <NUM> of a load that can be encountered during use in an elevator system <NUM> with, potentially, an additional factor of safety. In other words, the cords <NUM> remain at their original positions relative to the jacket <NUM> during use in an elevator system <NUM>. The jacket <NUM> could completely envelop the cords <NUM> (such as shown in <FIG>), substantially envelop the cords <NUM>, or at least partially envelop the cords <NUM>.

The portions <NUM>, <NUM>, <NUM> and <NUM> of the jacket <NUM> may be formed from a number of different materials. For example, in one embodiment, the traction portion <NUM> is formed from a first material, for example a thermoplastic polyurethane (TPU) material. The first material has desired mechanical properties for desired traction, low noise and wear properties. Further, in embodiments of elevator systems <NUM> where the back surface <NUM> back portion <NUM> contacts sheaves <NUM>, it may be desired to form back portion <NUM> from the first material to provide the same mechanical properties at the back portion <NUM> as at the traction portion <NUM>.

As stated above, the inner portion <NUM> of the belt <NUM> is located between the traction portion <NUM> and the back portion <NUM>. The inner portion <NUM> is configured to have a degree of fire resistance greater than the traction portion <NUM>. The inner portion <NUM> may be formed from a second material, such as a material including a percentage of melamine cyanurate (MC) to increase its fire resistance relative to the traction portion <NUM> material. In some embodiments, the inner portion <NUM> is approximately <NUM>% to <NUM>% of a thickness <NUM> of the belt <NUM>. The material layer thickness of the traction portion <NUM> and/or the back portion <NUM> may vary in thickness. Some embodiments may include an intermediate layer <NUM>, for example, a fiberglass fabric or wire metal mesh between the traction portion <NUM> and the inner portion <NUM> or as a replacement for the inner portion <NUM>. The intermediate layer <NUM> may be either embedded in the belt <NUM> or located at the back portion <NUM>. The inner portion <NUM> and/or the intermediate layer <NUM> are positioned and configured to prevent burn through or melt through of the belt <NUM> thus leading to improved fire resistance of belt <NUM>, while the traditional first material is utilized at the traction portion <NUM> to provide the expected traction, noise level, wear rate and other properties of belt <NUM> operation.

Referring to <FIG>, in an alternate embodiment the traction portion <NUM> is formed from the first material, and the remaining thickness of the belt <NUM>, extending to the back portion <NUM>, is formed from the second material, the inner portion <NUM> extending from the traction portion <NUM> and extending to and defining the back portion <NUM>.

Referring again to <FIG>, embodiments include one or more edge treatments to reduce the effect of flame spread and wraparound from the traction portion <NUM> to the back portion <NUM>, or vice versa. In the embodiment of <FIG>, the belt edge portion <NUM> are formed from the fire resistant second material, but in other embodiments may be formed from a different fire resistant material. The edge portion <NUM> extends inboard partially across the traction portion <NUM> and/or the back portion <NUM>. It is desired to minimize the wraparound flame spread so that the fire resistance of the edge portion <NUM> is maintained while minimizing the impact on performance of the traction portion <NUM>. In some embodiments, the edge portion <NUM> extends laterally inboard about <NUM>, but can vary according to desired performance.

The edge portions <NUM> may be formed in any one of several ways. One method of forming the edge portion <NUM> is illustrated in <FIG>. In the embodiment of <FIG>, the edge portion <NUM> is formed oversized in both thickness <NUM> and width <NUM>, and may be formed via, for example, co-extrusion with the traction portion <NUM>, the back portion <NUM> and the inner portion <NUM>, or may be formed via a secondary extrusion or other process. After forming, the edge portion <NUM> is trimmed along trim lines <NUM> to a selected shape to expose the fire retardant material of the edge portion <NUM>. The trimming operation allows for a well-defined transition area <NUM> between the first material of the traction portion <NUM> and the second material of the edge portion <NUM>, and ensures a selected thickness of the first material at the transition area <NUM>.

Referring now to <FIG>, in another embodiment the edge portion <NUM> is formed by trimming or by extruding or otherwise forming the belt <NUM> so that at least a portion of an end cord <NUM> is exposed. The metal material of the cord <NUM> acts as a fire resistant material to protect the belt <NUM>. In some embodiments, about <NUM>% to <NUM>% of a lateral width of the cord <NUM> is exposed, so the cord <NUM> provides fire resistance while still being securely retained in the jacket <NUM>. The cord cross-section for these end cords could deviate from circular and, for example, could be constructed of metallic strips or other fire resistant materials.

In other embodiments of belt <NUM> shown in <FIG>, the edge portion <NUM> is pre-formed separately rather than being formed as the material flowing through the extruder screw in an extrusion process. The pre-formed edge portion <NUM> is then fed into the extrusion die along with the cords <NUM>. The preformed edge portion <NUM> then joined to the other jacket portions <NUM>, <NUM>, <NUM> of the belt <NUM> via a combination of adhesion and mechanical interlocking. In the embodiments of <FIG>, the edge portion <NUM> is formed as a "C" geometry shape that achieves mechanical interlocking, but those skilled in the art will readily appreciate that edge portions <NUM> may be formed to other geometric shapes. In some embodiments, such as in <FIG>, one or more cords <NUM> may be positioned within an envelope of the edge portion <NUM>, particularly in those embodiments where edge portion <NUM> material has desired wear and noise performance properties. With this approach, materials with greater fire resistance can be used without the need to be processable in the extruder screw and/or at the same time as the remaining jacket material. These preformed edge portions <NUM> can be made by separate extrusion, machining, lamination and other continuous processes.

Claim 1:
A belt (<NUM>) for suspending and/or driving an elevator car (<NUM>) of an elevator system (<NUM>) comprising:
a plurality of tension members arranged in a lengthwise direction; and
a jacket (<NUM>) substantially retaining the plurality of tension members, the jacket (<NUM>) defining a traction portion (<NUM>), a back portion (<NUM>), and an inner portion (<NUM>) between the traction portion (<NUM>) and the back portion (<NUM>);
wherein the traction portion (<NUM>) is formed from a first material and the inner portion (<NUM>) is formed from a second material having an increased fire resistance compared to the first material, and
characterized in that said belt (<NUM>) further comprises an edge treatment at one or more lateral edges of the belt (<NUM>) to increase fire resistance of the lateral edges and wherein the edge treatment has a C-shaped cross-section and mechanically interlocks with the jacket.