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 belts for supporting the elevator car and achieving the desired movement and positioning of the elevator car.

Where belts are used as a load bearing member, a plurality of tension elements are embedded in a common elastomer belt body. In an exemplary traction elevator system, a machine drives a traction sheave with which the belts, interact to drive the elevator car along a hoistway. Belts typically utilize tension members formed from steel elements, but alternatively may utilize tension members formed from other materials such as carbon fiber composites. Belts have been used in combination with a crowned traction sheave in many different system layouts and installations worldwide. The use of the crowned traction sheave ensures centering of the belt within the width of each groove of the traction sheave. However, the use of a crown on the traction sheave has several drawbacks such as uneven pressure distribution on the jacket as well as uneven load sharing by the cords inside the belt.

<CIT> discloses a lift system with a drive transmission arrangement consisting of flat belts and pulleys. The flat belt is provided on at least one of its sides with longitudinal ribs.

<CIT> discloses a load-bearing mechanism for a lift system with a drive side with two or three drive ribs and a deflecting side on the opposite side with a guide rib.

<CIT> discloses a flat belt with round tension members embedded within a jacket material.

<CIT> discloses a flat belt with grooves and transverse slots.

In one embodiment, there is disclosed a belt for an elevator system as recited in claim <NUM>.

In some embodiments a plurality of belt guide features are arrayed across a width of the belt.

In some embodiments the belt guide feature has a curvilinear cross-section.

In some embodiments the belt guide feature includes a plurality of belt guide feature segments separated along the belt length by a plurality of feature gaps.

In some embodiments the belt guide feature has a lower durometer than the traction surface.

In some embodiments the elevator system includes a hoistway, an elevator car located in the hoistway and movable along the hoistway, a traction sheave with flat traction surfaces and a belt as described above.

In some embodiments a biasing member is operably connected to the guide sheave to bias the guide sheave toward the belt.

In some embodiments a distance between the guide sheave and the traction sheave is in the range of <NUM> times and <NUM> times a traction sheave diameter.

In some embodiments a plurality of belts are arranged along a width of the flat traction sheave.

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

Referring now to <FIG>, an exemplary embodiment of an elevator system <NUM> is illustrated. The elevator system <NUM> includes an elevator car <NUM> configured to move vertically upwardly and downwardly within a hoistway <NUM> along a plurality of car guide rails (not shown). Guide assemblies mounted to the top and bottom of the elevator car <NUM> are configured to engage the car guide rails to maintain proper alignment of the elevator car <NUM> as it moves within the hoistway <NUM>.

The elevator system <NUM> also includes a counterweight <NUM> configured to move vertically upwardly and downwardly within the hoistway <NUM>. The counterweight <NUM> moves in a direction generally opposite the movement of the elevator car <NUM> as is known in conventional elevator systems. Movement of the counterweight <NUM> is guided by counterweight guide rails (not shown) mounted within the hoistway <NUM>. In the illustrated, non-limiting embodiment, at least one load bearing member, for example, a belt <NUM>, coupled to both the elevator car <NUM> and the counterweight <NUM> cooperates with a traction sheave <NUM> mounted to a drive machine <NUM>. To cooperate with the traction sheave <NUM>, at least one belt <NUM> bends in a first direction about the traction sheave <NUM>. Although the elevator system <NUM> illustrated and described herein has a <NUM>:<NUM> roping configuration, elevator systems <NUM> having other roping configurations such as <NUM>:<NUM> and hoistway layouts are within the scope of the present disclosure. The at least one belt <NUM> may also be routed over one or more other sheaves, for example, a deflector sheave <NUM> located between the traction sheave <NUM> and the elevator car <NUM>. While not shown in the embodiment of <FIG>, additional deflector sheaves <NUM> may be utilized in the elevator system <NUM> to direct the at least one belt <NUM> to selected positions in the hoistway <NUM>. For example, additional deflector sheaves <NUM> may be located between the traction sheave <NUM> and the elevator car <NUM> and/or between the traction sheave <NUM> and the counterweight <NUM>.

The elevator system <NUM> further includes one or more guide sheaves <NUM> configured to guide the belt <NUM>, such that the belt <NUM> is positioned in a desired location along the deflector sheave <NUM> and/or the traction sheave <NUM>. To prevent excessive wear of the belt <NUM> or to prevent inadvertent slippage of the belt <NUM>, the desired location is at or about a lateral center of the traction sheave <NUM>, as shown in <FIG>. Referring again to <FIG>, the belt <NUM> includes a traction surface <NUM> interactive with the traction sheave <NUM> to drive the elevator car <NUM> and/or the counterweight <NUM> of the elevator system <NUM>. The traction surface <NUM> may additionally be interactive with the deflector sheaves <NUM>. The belt <NUM> further includes a back surface <NUM> opposite the traction surface <NUM>. The back surface <NUM> is interactive with the guide sheaves <NUM> to guide positioning of the belt <NUM> relative to the traction sheave <NUM> and/or the deflector sheave <NUM>.

Referring again to <FIG>, the belt <NUM> includes plurality of tension members <NUM> extending along the belt <NUM> length and arranged across a belt width <NUM>. In some embodiments, the tension members <NUM> are equally spaced across the belt width <NUM>. The tension members <NUM> are at least partially enclosed in a jacket material <NUM> to restrain movement of the tension members <NUM> in the belt <NUM> and to protect the tension members <NUM>. The jacket material <NUM> defines the traction surface <NUM> configured to contact a corresponding surface of the traction sheave <NUM>. Exemplary materials for the jacket material <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 material <NUM> if they are adequate to meet the required functions of the belt <NUM>. For example, a primary function of the jacket material <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 material <NUM> should also transmit the traction loads to the tension members <NUM>. In addition, the jacket material <NUM> should be wear resistant and protect the tension members <NUM> from impact damage, exposure to environmental factors, such as chemicals, for example.

In some embodiments, as shown in <FIG>, each tension member <NUM> is formed from a plurality of metallic, for example steel, wires <NUM>, arranged into a plurality of strands <NUM>, which are in turn arranged into a cord, or tension member <NUM>. In other embodiments, the tension members <NUM> may be formed from other materials and may have other configurations. For example, in some embodiments, such as shown in <FIG>, the tension member <NUM> may be formed from a plurality of fibers arranged in a rigid matrix composite. While in the embodiment shown there are six tension members <NUM> in the belt <NUM>, the number of tension members <NUM> is merely exemplary. In other embodiments, for example, one, two, three, four, five, six or more tension members <NUM> may be utilized. It is to be appreciated that arrangement of wires <NUM> shown in <FIG> is merely exemplary, and that other arrangements of wires <NUM> to form tension members <NUM> are contemplated within the scope of the present disclosure.

Referring again to <FIG>, the guidance of the belt <NUM> to the deflector sheave <NUM> and/or the traction sheave <NUM> is provided by one or more belt guide features <NUM> at the back surface <NUM> of the belt <NUM> that are configured to mesh with complimentary guide sheave features <NUM> of the guide sheave <NUM>. In an embodiment of the invention, such as shown in <FIG>, the belt guide features <NUM> each include a convex arc extending outwardly from the back surface <NUM>, while the guide sheave features include a concave arc located at a guide sheave surface <NUM>. In some embodiments, multiple guide features may be utilized across the belt width <NUM> as shown in <FIG>, while in other embodiments, a single belt guide feature <NUM> and complimentary guide sheave feature <NUM> may be used to guide the belt <NUM>.

Referring now to <FIG>, in other arrangements, the belt guide features <NUM> and complimentary guide sheave features <NUM> may have other shapes, such as a "V"-shape or taper as shown. Further, a single belt guide feature <NUM> and complimentary guide sheave feature <NUM> may be utilized, as shown in <FIG>. In the arrangement of <FIG>, the "V"-shape is continuous over the entire belt width <NUM>, but in other embodiments, the "V"-shape may extend partially across the belt width <NUM>. The shapes and configurations of belt guide features <NUM> and complimentary guide sheave features <NUM> disclosed herein are merely exemplary, and one skilled in the art will recognize that other shapes and configurations of such features may be utilized.

Referring now to <FIG>, illustrated is a traction sheave <NUM> and guide sheave <NUM> arrangement for an elevator system <NUM> having multiple belts <NUM>. The traction sheave <NUM> includes a sheave location or groove <NUM> for each belt <NUM> of the elevator system <NUM>. The guide sheave <NUM> includes multiple arrangements of guide sheave features <NUM>, one set of guide sheave features <NUM> for each belt <NUM>, which interact with the belt guide features <NUM> of each belt <NUM>. The guide sheave surface <NUM> may be continuous across the multiple belt width, or as shown in <FIG>, may comprise multiple guide sheave surfaces <NUM> supported by an axle <NUM>. Further, as shown, in some embodiments, a biasing member <NUM> such as a spring may be utilized to bias a position of the guide sheave toward the belt <NUM>, urging the guide sheave features <NUM> into interactive contact with the belt guide features <NUM> of the belt <NUM>.

One concern with the addition of belt guide features <NUM> to the back surface <NUM> is a potential increase in stiffness of the belt <NUM>, limiting the ability of the belt <NUM> to conform to the shape of the traction sheave <NUM> and/or the deflector sheave <NUM>. In some embodiments, to reduce the stiffness of the belt <NUM>, a height of the belt guide features <NUM> is below about <NUM>. In some embodiments, the belt guide features <NUM> may be discontinuous along the belt <NUM> length. For example, as shown in <FIG>, the belt guide features <NUM> may comprise a plurality of feature segments <NUM> extending along the belt <NUM> length. The feature segments <NUM> are separated by a feature gap <NUM>, which results in a reduction of belt <NUM> stiffness compared to a belt <NUM> with continuous belt guide features <NUM>. In other embodiments, such as shown in <FIG>, the belt guide features <NUM> may be formed continuous along the belt <NUM> length, then segmented into feature segments <NUM> by a cutter or other tool, allowing the belt <NUM> to more readily conform to the traction sheave <NUM> and/or the deflector sheave <NUM>. The Further, the guide features <NUM> may be formed from a material different from the jacket material <NUM> with a selected hardness so the effect of the guide features <NUM> on bending stiffness of the belt <NUM> is minimized. For example, in some embodiments the guide features <NUM> may be formed having a durometer hardness of between <NUM> and <NUM> on the Shore A hardness scale, while the traction surface <NUM> has a durometer hardness of over <NUM>. The guide features <NUM> may be co-extruded with the jacket material <NUM> to form the belt <NUM> or alternatively may be formed separately and bonded to the jacket material <NUM> after the jacket material <NUM> is formed over the tension members <NUM>.

A distance between the guide sheave <NUM> and the associated deflector sheave <NUM> or traction sheave <NUM> determines a "force" necessary to steer the belt <NUM> to the desired position at the deflector sheave <NUM> or traction sheave <NUM>. The larger the distance, the smaller the force required. On the other hand the guide sheave <NUM> must be close enough to the associated deflector sheave <NUM> or traction sheave <NUM> to control the belt <NUM> position and effectively guide the belt <NUM>. In some embodiments a distance between the guide sheave <NUM> and the associated deflector sheave <NUM> or traction sheave <NUM> is between about <NUM> and <NUM> times a deflector sheave <NUM> diameter or traction sheave <NUM> diameter.

Incorporating belt guide features <NUM> at the back surface <NUM> of the belt <NUM> allows for the removal of guide features such as crowns or the like from the traction sheave reducing the stress gradient across the belt width at the traction sheave thereby reducing wear of portions of the belt. Further, flanges typically utilized at the traction sheave to contain the belt at the traction sheave may be reduced or removed. Further still, since the belt guide features <NUM> and the guide sheave <NUM> align the belt <NUM> before encountering the traction sheave <NUM>, a width of the traction sheave <NUM> may be reduced. <NUM> is between about <NUM> and <NUM> times a deflector sheave <NUM> diameter or traction sheave <NUM> diameter.

Incorporating belt guide features <NUM> at the back surface <NUM> of the belt <NUM> allows for the removal of guide features such as crowns or the like from the traction sheave reducing the stress gradient across the belt width at the traction sheave thereby reducing wear of portions of the belt. Further, flanges typically utilized at the traction sheave to contain the belt at the traction sheave may be reduced or removed. Further still, since the belt guide features <NUM> and the guide sheave <NUM> align the belt <NUM> before encountering the traction sheave <NUM>, a width of the traction sheave <NUM> may be reduced.

Claim 1:
A belt (<NUM>) for an elevator system (<NUM>) comprising:
a plurality of tension members (<NUM>) arranged along a belt width (<NUM>); and
a jacket material (<NUM>) at least partially encapsulating the plurality of tension members (<NUM>) defining:
a traction surface (<NUM>) interactive with a traction sheave (<NUM>) of an elevator system (<NUM>);
a back surface (<NUM>) opposite the traction surface (<NUM>), the back surface (<NUM>) including a belt guide feature (<NUM>) extending along a belt length and interactive with a complimentary guide sheave feature (<NUM>) of a guide sheave (<NUM>) of the elevator system (<NUM>) to orient the belt (<NUM>) to a selected location during operation of the elevator system (<NUM>); the belt guide feature (<NUM>) is a convex arc feature protruding outwardly from the back surface (<NUM>); and
characterized in that the belt guide feature (<NUM>) is discontinuous along the belt length.