Patent Description:
Elevator systems are useful for carrying passengers, cargo, or both, between various levels in a building. Some elevators are traction based and utilize load bearing members such as ropes or belts for supporting the elevator car and achieving the desired movement and positioning of the elevator car.

As buildings reach new heights in their construction, with some architectural designs over <NUM> kilometer, more advanced hoisting methods are necessary for efficient transport of people and materials throughout the building. One limitation of conventional hoisting is the weight of conventional steel cable as it is only capable of rises of ~ <NUM>. To address this, tension members have been developed using carbon fiber tension elements as these have a substantially higher specific strength and will allow hoisting solutions that can accommodate the proposed architectural designs of over <NUM> kilometer and there is an advantage of using lightweight tension members in buildings of even rises down to ~ <NUM>.

<CIT> discloses a synthetic fiber rope comprising at least an inner layer and an outer layer of load-bearing synthetic fiber strands laid together, said layers being concentric and radically separated from one another forming an interlayer space, and a tubular shaped intersheath positioned in said interlayer space between said layers and enveloping said inner layer, said intersheath being elastically deformable and having a plurality of grooves formed therein, each one of said grooves being contoured to receive an associated one of said fiber strands of am adjacent one of said layers.

<CIT> discloses a tension member for a hoisting device. The tension member is a load bearing structure comprising a center string and several load bearing strings twisted around the center string in a helical formation.

<CIT> discloses a tension member disclosing the features of the preamble of the independent claims, for a hosting system comprising a core including a plurality of individual load carrying fibers arranged unidirectionally, substantially in a direction parallel to a tension member length in a matrix material, and an outer layer secured to the core and arranged around a perimeter of the core. The outer layer comprises fiber tapes, wherein fibers are braided or woven into a flat, flexible, tape-like structure.

Where ropes are used as load bearing members, each individual rope is not only a traction device for transmitting the pulling forces but also participates directly in the transmission of the traction forces. Where belts are used as a load bearing member, a plurality of tension elements are embedded in an elastomer belt body. The tension elements are exclusively responsible for transmitting the pulling forces, while the elastomer material transmits the traction forces. Due to their light weight and high strength, tension members formed from unidirectional fibers arranged in a rigid matrix composite provide significant benefits when used in elevator systems, particularly high rise systems. The fibers are impregnated with thermosetting resins and then cured to form rigid composites that are surrounded with the elastomer to provide traction for the belt.

Subject-matter of the invention is a tension member having the features indicated in claim <NUM>, a belt having the features indicated in claim <NUM>, and a method of forming a tension member having the features indicated in claim <NUM>. Embodiments of the invention are defined in the respective dependent claims.

The detailed description explains disclosed embodiments, together with advantages and features, by way of example with reference to the drawings.

Shown in <FIG>, is a schematic view of an exemplary traction elevator system <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 tension members <NUM>. The one or more tension members <NUM> interact with one or more sheaves <NUM> to be routed around various components of the elevator system <NUM>. The one or more tension members <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 traction sheave <NUM>. The traction sheave <NUM> is driven by a machine <NUM>. Movement of drive sheave by the machine <NUM> drives, moves and/or propels (through traction) the one or more tension members <NUM> that are routed around the traction sheave <NUM>. At least one of the sheaves <NUM> could be a diverter, deflector or idler sheave. Diverter, deflector or idler sheaves are not driven by a machine <NUM>, but help guide the one or more tension members <NUM> around the various components of the elevator system <NUM>.

In some embodiments, the elevator system <NUM> could use two or more tension members <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 tension members <NUM> engage the one or more sheaves <NUM> or only one side of the one or more tension members <NUM> engages the one or more sheaves <NUM>. The embodiment of <FIG> shows a <NUM>:<NUM> roping arrangement in which the one or more tension members <NUM> terminate at the car <NUM> and counterweight <NUM>, while other embodiments may utilize other roping arrangements.

Referring now to <FIG>, a cross-sectional view of an embodiment of a tension member <NUM> is shown. The tension member <NUM> includes a core <NUM> formed from a plurality of individual load carrying fibers <NUM> arranged unidirectionally, substantially in a direction parallel to a tension member <NUM> length, within a matrix material <NUM>.

Exemplary load carrying fibers <NUM> used to form the core <NUM> include, but are not limited to, carbon, glass, aramid, nylon, and polymer fibers, for example. Each of the load carrying fibers <NUM> within the core <NUM> may be substantially identical or may vary. In addition, the matrix material <NUM> may be formed from any suitable material, such as polyurethane, vinylester, and epoxy for example. The materials of the load carrying fibers <NUM> and the matrix material <NUM> are selected to achieve a desired stiffness and strength of the tension member <NUM>.

The core <NUM> may be formed as thin layers, in some embodiments by a pultrusion process. In a standard pultrusion process, the load carrying fibers <NUM> are impregnated with the matrix material <NUM> and are pulled through a heated die and additional curing heaters where the matrix material <NUM> undergoes cross linking. A person having ordinary skill in the art will understand that controlled movement and support of the pulled load carrying fibers <NUM> may be used to form a desired linear or curved profile of the untensioned core <NUM>. In an exemplary embodiment, the core <NUM> has a cross-sectional thickness of about <NUM> millimeters to about <NUM> millimeters. In another embodiment, the core <NUM> has a cross-sectional thickness of <NUM> millimeter. Further, in some embodiments the core <NUM> has a circular cross-section, while in other embodiments the core <NUM> may have other cross-sectional shapes, such as rectangular or oval.

The tension member <NUM> further includes an outer layer <NUM> formed from braided or woven fibers that substantially envelops the core <NUM>. The outer layer <NUM> may be applied to the core <NUM> by, for example wrapping around the core <NUM> or braiding around the core <NUM>. The outer layer <NUM> is formed from fibers of, for example, carbon, glass, aramid, nylon, or polymer fibers. In some embodiments, the outer layer <NUM> material is the same as the core <NUM> material, while in other embodiments the materials may differ. Further, in other embodiments the outer layer <NUM> is formed from metallic wires. The braiding of the outer layer <NUM> orients fibers off-axis relative to the core <NUM> to support off-axis stresses on the tension member <NUM>. Further, the outer layer <NUM> can have lower stiffness which reduces bending stresses and allows the overall tension member <NUM> to have a larger thickness or diameter than just an aligned fiber tension member. While in the embodiment of <FIG>, the outer layer <NUM> and the core <NUM> are separate and distinct, in other embodiments the outer layer <NUM> and the core may be intermingled via, for example, the matrix material <NUM> flowing into the outer layer <NUM> during manufacturing or during post-processing to remove any sharp boundaries between the core <NUM> and the outer layer <NUM>. Further, the outer layer <NUM> can be formed using materials to improve performance during a fire or thermal event or during other conditions.

Referring now to <FIG>, in some embodiments one or more tension members <NUM> are utilized as cables to support and/or drive the elevator car <NUM>. In such embodiments, the tension members <NUM> are routed over the traction sheave <NUM>, which may include sheave grooves <NUM> to position the tension members <NUM> at the traction sheave <NUM>. In some embodiments, the outer layer <NUM> is configured to have sufficient flexibility to conform to the sheave grooves <NUM>.

Referring now to <FIG>, one or more tension members <NUM> may be utilized in a belt <NUM>, which suspends and/or drives the elevator car <NUM>. The one or more tension members <NUM> are arranged in a jacket <NUM>. The tension members <NUM> extend along a length of the belt <NUM>, and are arranged across a lateral width of the belt <NUM>, and in some embodiments are spaced from each other as shown in <FIG>.

The tension members <NUM> are at least partially enclosed in the jacket <NUM>, to restrain movement of the tension members <NUM> in the belt <NUM> and protect the tension members <NUM>. In embodiments including the jacket <NUM> defines a traction surface <NUM> configured to contact a corresponding surface of the traction sheave <NUM>. Exemplary materials for the jacket <NUM> include the elastomers of thermoplastic and thermosetting polyurethanes, polyamide, thermoplastic polyester elastomers, and rubber, for example. Other materials may be used to form the jacket <NUM> if they are adequate to meet the required functions of the belt <NUM>. For example, a primary function of the jacket <NUM> is to provide a sufficient coefficient of friction between the belt <NUM> and the traction sheave <NUM> to produce a desired amount of traction therebetween. The jacket <NUM> should also transmit the traction loads to the tension members <NUM>. In addition, the jacket <NUM> should be wear resistant and protect the tension members <NUM> from impact damage, exposure to environmental factors, such as chemicals, for example. One or more additive materials may be incorporated into the jacket <NUM> to enhance performance such as traction and environmental resistance. In embodiments with the jacket <NUM>, the outer layer <NUM> with the off-axis fibers promotes improved adhesion between the tension members <NUM> and the jacket <NUM>.

Referring now to <FIG>, shown is a schematic view of a process for manufacturing a tension member <NUM>, which is illustrated as a continuous manufacturing process. Load carrying fibers <NUM> are fed from a core reel <NUM>, aligned or grouped, then impregnated with the matrix material <NUM> at an impregnation bath <NUM> to form the core <NUM>. The outer layer <NUM> is formed over the core <NUM> by feeding outer yarns <NUM> into a braider <NUM> and through an impregnation ring <NUM> to impregnate the braided outer yarns <NUM> with matrix material. The braided and impregnated outer yarns <NUM> are positioned around the core <NUM> and positioned at the core <NUM> by passing the core <NUM> and the outer yarns <NUM> through one or more rollers <NUM>. The assembled core <NUM> and outer layer <NUM> are then passed through an oven <NUM> or other curing apparatus to at least partially set the matrix material. The assembly then passes through a puller <NUM> to apply tension to the load carrying fibers <NUM> of the core <NUM> to their final set position. The assembly can then be cut to length and/or spooled for subsequent fabrication of the belt <NUM>.

Claim 1:
A tension member (<NUM>) for a lifting and/or hoisting system comprising:
a core (<NUM>) including a plurality of individual load carrying fibers (<NUM>) arranged unidirectionally, substantially in a direction parallel to a tension member (<NUM>) length in a matrix material (<NUM>); and
an outer layer (<NUM>) secured to the core (<NUM>) including a plurality of outer fibers arranged around a perimeter of the core, wherein the outer layer (<NUM>) includes a plurality of outer fibers arranged off-axis relative to the load carrying fibers (<NUM>) of the core (<NUM>),
characterized in that the plurality of outer fibers are braided around the core to form the outer layer (<NUM>).