Patent Description:
Elevator sheaves include a surface that engages the roping. Different roping configurations exist, such as round steel ropes and flat belts. There are different sizes of belts for different duty or load capacities. While a variety of roping options are useful, they present the challenge of maintaining inventory of a corresponding variety of sheaves for installation or replacement over time.

<CIT> discloses a belted elevator system including a hoistway and an elevator car suspended in the hoistway via a suspension member and drivable along the hoistway. The suspension member is routed over a plurality of sheaves. A sheave of the plurality of sheaves includes a shaft defining a central axis of the sheave, the sheave rotatable about the central axis. A sheave outer member is operably connected to the shaft and rotatable about the central axis. The sheave outer member includes a sheave outer surface interactive with the suspension member. The sheave outer member is formed from a molded plastic material.

<CIT> discloses a modular pulley assembly for a continuous belt conveyor can be assembly from a plurality of modular pulley disks that can be axially aligned and abut against each other to provide pulleys of differing lengths per demand. The modular pulley disks can be made from a non-metallic material such as a polymer and can manufactured by a suitable molding process.

The invention provides an elevator sheave assembly according to claim <NUM> and a method of making an elevator sheave assembly according to claim <NUM>.

Preferred features are set out in the dependent claims.

<FIG> schematically illustrates selected portions of an elevator system <NUM>. An elevator car <NUM> is coupled to a counterweight <NUM> by roping <NUM>. Although not shown in detail, the roping <NUM> includes a plurality of tension members, which in this case comprise flat belts. The roping <NUM> follows a path defined, at least in part, by sheaves <NUM>. At least one of the sheaves <NUM> is a traction sheave associated with a machine <NUM> that selectively causes movement of the roping <NUM> to control the movement and position of the elevator car <NUM> for providing elevator service to passengers. The other illustrated sheave <NUM> is an idler sheave that rotates as the roping <NUM> moves during movement of the elevator car <NUM>.

<FIG> shows an elevator sheave assembly (not covered by the claims but useful for understanding the invention) that is useful, for example, as the idler sheave <NUM>. The elevator sheave assembly includes a plurality of polymer rings that are secured together to establish at least one belt-guiding surface. The plurality of polymer rings in the example embodiment of <FIG> includes two polymer rings, one of which is a first polymer end ring <NUM> at a first longitudinal end of the sheave assembly. The first polymer end ring <NUM> includes an outer circumferential surface <NUM> having a first profile that defines a portion <NUM> of a belt-guiding surface. A flange <NUM> is situated along an outer lateral edge of the first polymer end ring <NUM>. The flange <NUM> establishes one end of the belt-guiding surface.

The other of the two polymer rings in this example embodiment is a second polymer end ring <NUM> situated at a second, opposite longitudinal end of the elevator sheave assembly. The second polymer end ring <NUM> includes an outer circumferential surface <NUM> that defines another portion <NUM> of the belt-guiding surface. A flange <NUM> at an outer lateral edge of the second polymer end ring <NUM> establishes another outer edge of the belt-guiding surface.

Each of the two polymer end rings <NUM>, <NUM> includes a bearing <NUM> supported within the ring. The polymer material of the polymer rings <NUM>, <NUM> is over-molded onto the respective bearing <NUM> so that the bearing is maintained within a groove <NUM> that is molded about the exterior of the bearing <NUM>.

The example of <FIG> is configured to accommodate a single belt on the belt-guiding surface comprising the portions <NUM> and <NUM>. Other embodiments are configured to accommodate a plurality of belts.

An example embodiment configured to accommodate two belts is shown in <FIG> where the outer circumferential surface <NUM> defines a first portion <NUM> of a first belt-guiding surface and the outer circumferential surface <NUM> defines a first portion <NUM> of a second belt-guiding surface. At least one polymer intermediate ring <NUM> is situated between and connected to the first polymer end ring <NUM> and the second polymer end ring <NUM>. The polymer intermediate ring <NUM> includes an outer circumferential surface <NUM> having a profile that includes a rib <NUM>. The profile of the outer circumferential surface <NUM> defines a second portion <NUM> of the first belt-guiding surface and a second portion <NUM> of the second belt-guiding surface. The rib <NUM> separates the first belt-guiding surface <NUM>, <NUM> from the second belt-guiding surface <NUM>, <NUM>.

The first polymer end ring <NUM> is connected to the polymer intermediate ring <NUM> along adjacent lateral edges of those rings. Similarly, the second polymer end ring <NUM> is connected to the polymer intermediate ring <NUM> along adjacent lateral edges of those rings. All of the polymer rings <NUM>, <NUM> and <NUM> are fixed together so that they rotate in unison during movement of the flat belts of the roping <NUM>.

The first polymer end ring <NUM> and the second polymer end ring <NUM> in this embodiment each include a bearing <NUM>. The polymer material of each ring is over-molded onto the bearing <NUM> such that the bearing remains fixed in a desired location between the lateral edges of the ring. Over-molding the polymer material onto the bearing <NUM> of each ring allows for strategically placing the bearing <NUM> at a location where load on the ring will be concentrated as the sheave <NUM> engages the roping <NUM>, which suspends the load of the elevator car <NUM> and counterweight <NUM>.

As shown in <FIG>, retention rings <NUM> are received in notches in a shaft <NUM> that defines an axis of rotation of the sheave <NUM>. The bearings <NUM> rotate about the shaft <NUM> to facilitate rotation of the sheave <NUM>.

In the embodiment shown in <FIG>, the intermediate ring <NUM> does not include its own bearing <NUM>. Another example embodiment is shown in <FIG> in which the intermediate ring <NUM> includes its own bearing <NUM>. The embodiment in <FIG> is configured to accommodate belts of a wider width compared to those that would be used with the sheave <NUM> shown in <FIG>. The additional width of the belt guiding surfaces is accommodated by a larger longitudinal dimension of the polymer intermediate ring <NUM> in the embodiment shown in <FIG>.

<FIG> shows another embodiment of an elevator sheave assembly that includes a plurality of polymer intermediate rings. A first polymer intermediate ring <NUM> is received against and connected to an inner lateral edge of the first polymer end ring <NUM>. The first polymer intermediate ring <NUM> has an outer circumferential surface <NUM> with a profile that defines a second portion <NUM> of the first belt-guiding surface. The outer circumferential surface <NUM> also defines a first portion <NUM> of a third belt-guiding surface. A rib <NUM> separates the second portion <NUM> of the first belt-guiding surface from the first portion <NUM> of the third belt-guiding surface.

A second polymer intermediate ring <NUM> has one lateral edge received against an inner lateral surface of the second polymer end ring <NUM>. Another lateral edge of the second polymer intermediate ring <NUM> is received against an adjacent lateral surface on the first polymer intermediate ring <NUM>. All of the rings <NUM>, <NUM>, <NUM> and <NUM> are secured together to rotate in unison.

The second polymer intermediate ring <NUM> includes an outer circumferential surface <NUM> that defines a second portion <NUM> of the second belt-guiding surface and a second portion <NUM> of the third belt-guiding surface. A rib <NUM> separates the portions of the second polymer intermediate ring <NUM> that contribute to the second and third belt-guiding surfaces, respectively.

The embodiment of <FIG> is configured to accommodate three belts. <FIG> shows another embodiment that is configured to accommodate four belts. In this example embodiment, a third polymer intermediate ring <NUM> is situated between the first polymer intermediate ring <NUM> and the second polymer intermediate ring <NUM>. The third polymer intermediate ring <NUM> also has an outer circumferential surface <NUM>. The profile of the outer surface <NUM> defines a second portion <NUM> that cooperates with the portion <NUM> of the first polymer intermediate ring <NUM> to establish a third belt-guiding surface. Another portion <NUM> of the outer surface <NUM> cooperates with the portion <NUM> of the second polymer intermediate ring <NUM> to establish a fourth belt-guiding surface. A rib <NUM> separates the portions <NUM> and <NUM> and establishes an inner edge of each of the third belt guiding surface and the fourth belt guiding surface.

The embodiment in <FIG> includes another polymer intermediate ring and is configured to accommodate five belts. In this embodiment, the polymer intermediate ring 100A includes an outer circumferential surface 102A having a profile including a portion 104A that, together with the portion <NUM> of the first polymer intermediate ring <NUM>, defines a third belt-guiding surface. The polymer intermediate ring 100B has an outer circumferential surface 102B including a portion 104B that, together with the portion <NUM> of the second polymer intermediate ring <NUM>, defines a fourth belt-guiding surface. Portions 106A and 106B define a fifth belt-guiding surface at a longitudinal center of the sheave assembly.

As can be appreciated from the drawings, the first polymer end ring <NUM> and the second polymer end ring <NUM> have the same configuration with the same profile on the outer circumferential surfaces <NUM> and <NUM>. In other words, the polymer end rings <NUM> and <NUM> are interchangeable because they are identical components. Similarly, the first polymer intermediate ring <NUM> and the second polymer intermediate ring <NUM> are identical components. The polymer intermediate rings <NUM>, 100A and 100B are identical. With just those three configurations of a polymer ring, a variety of elevator sheave assembly configurations are possible to accommodate a desired number of belts. Additionally, depending on which polymer ring is selected for each position in the elevator sheave assembly, different belt widths can be accommodated.

Including an intermediate ring such as the polymer intermediate ring <NUM> shown in <FIG> brings the total number of different ring components up to four. It follows that with just four types of rings, a wide range of elevator sheave assembly configurations are possible. The modularity and interchangeability of the polymer rings simplifies the task of maintaining adequate inventory of sheave assembly components to meet the needs of a variety of elevator installations.

One way in which the example elevator sheave assemblies differ from traditional, metal sheave configurations is that the bearings <NUM> are strategically placed at selected locations along the entire length of the sheave assembly. With traditional, metal sheave configurations, bearings could be press fit only into the ends of a sheave but were not present in the central portion of the sheave. With the individual polymer rings each having a bearing, it is possible to strategically distribute the load across the bearings along the entire length of the sheave. The position of the bearings <NUM> within each ring can be selected to be aligned with a concentration of load on that ring when the elevator sheave assembly is used in the elevator system <NUM>.

In some embodiments, the polymer material used for making the rings is a plastic material comprising nylon. One example material is known in the industry as nylon <NUM> and includes glass fiber content on the order of <NUM>% to <NUM>%. Such polymer materials provide some flexibility or resilience along the length of the elevator sheave assembly. That aspect of the polymer material contributes to being able to strategically locate a bearing at a position where the load on the ring is most concentrated when the elevator sheave assembly is in use in an elevator system.

The polymer rings of the illustrated example embodiments may have the entire profile of the outer circumferential surface established during a molding process in which the ring is molded. Alternatively, as shown in <FIG>, a separate flange <NUM> may be secured to an outer lateral edge of a polymer end ring.

The elevator sheave assemblies described above can be made or assembled by connecting selected polymer rings together. <FIG> shows one example arrangement in which the polymer rings include recesses <NUM> on at least one lateral surface of the ring. Connectors <NUM> are received in the recesses for securing two adjacent rings together. <FIG> shows another example embodiment in which spring pins <NUM> are used as the connectors.

<FIG> illustrates an embodiment in which the rings include recesses <NUM> and proj ections <NUM> on at least one lateral surface. The arrangement of recesses <NUM> and projections <NUM> are the same on each of the illustrated rings <NUM> and <NUM>. The projections <NUM> are configured to be at least partially received within the recesses <NUM> for securing two adjacent rings together. Depending on the configuration of the connectors <NUM>, <NUM> or the projections <NUM>, an adhesive may be used to establish a permanent connection between adjacent rings.

<FIG> illustrates an embodiment including first and second polymer end rings <NUM> and <NUM> with one intermediate ring <NUM> between the end rings. The rings <NUM>, <NUM> and <NUM> collectively establish a single belt-guiding surface having portions <NUM>, <NUM> and <NUM>. Each of the rings <NUM>, <NUM> and <NUM> includes a bearing <NUM> within the ring. The single belt-guiding surface has three associated bearings <NUM>, which can be useful, for example, when the expected load on the corresponding belt requires such support.

The example embodiments include multiple rings and multiple bearings <NUM> for each belt-guiding surface. In some of the disclosed embodiments, the number of bearings equals the number of rings and there are at least two bearings for each belt-guiding surface because each ring has an associated bearing. In other embodiments, there are more than two bearings for each belt-guiding surface or less than two bearings for each belt-guiding surface.

<FIG> includes a flow chart diagram <NUM> that summarizes a method of making an elevator sheave assembly consistent with the embodiments discussed above. In the case of <FIG>, at least one polymer intermediate ring is included between the first and second polymer end rings <NUM>, <NUM>. The example method includes, at <NUM>, situating the first polymer end ring <NUM> at a first longitudinal end of the sheave assembly. At <NUM>, a polymer intermediate ring <NUM> is connected to the first polymer end ring <NUM>. At <NUM>, the polymer intermediate ring <NUM> is connected to the second polymer end ring <NUM> to situate the second polymer end ring at a second longitudinal end of the sheave assembly.

Utilizing polymer rings of the type shown in the drawings and described above allows for accommodating a variety of sheave requirements in a variety of elevator system configurations. Having four basic polymer ring components allows for any number of belts to be accommodated and for establishing belt-guiding surfaces that can accommodate belts of different widths.

Claim 1:
An elevator sheave assembly (<NUM>), comprising a plurality of polymer rings (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, 100A, 100B) that are secured together, the plurality of polymer rings (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, 100A, 100B) including at least two polymer rings (<NUM>, <NUM>) that each have an outer circumferential surface (<NUM>, <NUM>) that defines a portion of a belt guiding surface adjacent a flange at a longitudinal end of the sheave assembly (<NUM>), the at least two polymer rings (<NUM>, <NUM>) each including a bearing (<NUM>) supported inside the ring; wherein
the at least two polymer rings are a first polymer end ring (<NUM>) and a second polymer end ring (<NUM>);
the first polymer end ring (<NUM>) is at a first longitudinal end of the sheave assembly (<NUM>);
the outer circumferential surface (<NUM>) of the first polymer end ring (<NUM>) has a first profile that defines a first portion (<NUM>) of a first belt-guiding surface;
the second polymer end ring (<NUM>) is at a second longitudinal end of the sheave assembly (<NUM>);
the outer circumferential surface (<NUM>) of the second polymer end ring (<NUM>) has a second profile that defines a first portion (<NUM>) of a second belt-guiding surface;
the plurality of polymer rings (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>) includes at least one polymer intermediate ring (<NUM>, <NUM>, <NUM>, <NUM>, 100A, 100B) situated between and connected to the first (<NUM>) and second (<NUM>) polymer end rings; and
charactenzed in that the
at least one polymer intermediate ring (<NUM>, <NUM>, <NUM>, <NUM>, 100A, 100B) includes an outer circumferential surface having a profile that defines a second portion (<NUM>) of the first belt-guiding surface and a second portion (<NUM>) of the second belt-guiding surface.