HK1129871B - Method of making a load bearing member for an elevator system - Google Patents

Description

Method of manufacturing a load bearing member for an elevator system

Technical Field

This invention generally relates to elevator systems. More particularly, the present invention relates to a load bearing member for an elevator system.

Background

There are several known types of elevator systems. Traction-based systems typically include an elevator car, a counterweight, and a load bearing member supporting the car and counterweight. The car moves between different heights due to e.g. traction forces between the load bearing members and the traction sheave.

Elevator system load bearing members are formed in different forms. Steel cords have been used for many years. More recently, other load bearing members have been introduced. Some examples include a flat belt having a plurality of tension members encased within a urethane jacket. Some examples include steel cords as the tension members, while others include aramid materials as the tension members.

Regardless of the material selected, known manufacturing methods typically result in a plurality of grooves in at least one exterior surface of the jacket. These grooves are produced as a result of known manufacturing processes.

One difficulty associated with such grooves is that they tend to introduce noise and vibration when the grooves contact the traction sheave, such as during elevator system operation. Different arrangements have been proposed to minimize vibration and noise due to the influence of such grooves.

It would be advantageous to be able to eliminate the grooves completely. The present invention addresses this need.

Disclosure of Invention

An exemplary load bearing member for an elevator system includes at least one tension member and a jacket generally surrounding the tension member. The sheath does not have any external grooves.

The jacket in one example is made by a method that includes placing at least one tension member adjacent one side of a first jacket layer that includes a polymer, and adding a second jacket layer that includes urethane to at least one side of the first jacket layer such that the tension member is between the first and second layers.

In one example, a method of making a load bearing member for use in an elevator system is disclosed, comprising the steps of: (A) placing at least one tensioning member adjacent one side of a first jacket layer comprising a polymer, the first jacket layer abutting an outer surface of a contoured wheel with a recess; and (B) subsequently, adding a second jacket layer comprising a polymer at least adjacent to at least one side of the first jacket layer such that the tension members are located between the first and second jacket layers and are at least partially encapsulated within the second jacket layer, wherein step (B) comprises employing a temperature of at least one of the first or second jacket layers sufficient to cause at least partial melting of at least one of the two layers, thereby bonding the first and second layers together.

In one example, the tension member includes a plurality of steel cords (steel cables). In one example, there are a plurality of tension members.

In one example, the first and second layers are made of the same material including urethane. In another example, each layer is selected from a different material. In one example, the different materials have different frictional characteristics.

An exemplary method of making a load bearing member for an elevator system comprises: at least one tension member is positioned adjacent one side of the first jacket layer comprising a polymer. Adding a second layer comprising urethane to at least one side of the first layer completes the load bearing member with the tension member positioned between the first and second layers.

In one example, the method includes heating the tension member sufficiently to cause the first layer to at least partially melt in the vicinity of the tension member. This ensures, for example, a good bond between the tension member and the first layer.

In one example, the second layer is extruded onto the first layer. The temperature of the extruded material is sufficient to provide bonding between the first and second layers.

In one example, a load bearing member for use in an elevator system is disclosed that includes at least one tension member generally surrounded by a jacket, the load bearing member being manufactured by the above-described method.

The different features and advantages of the invention will become clear to those skilled in the art from the following description of a generally preferred embodiment. The drawings that accompany the detailed description can be briefly described as follows.

Drawings

Fig. 1 schematically illustrates selected portions of an elevator system;

FIG. 2 is a schematic perspective end view of an exemplary embodiment of a load bearing member;

FIG. 3 schematically illustrates a configuration (or arrangement) for manufacturing one exemplary embodiment of a load bearing member; and

fig. 4A-4C schematically illustrate selected features of an exemplary manufacturing process.

Detailed Description

Fig. 1 schematically illustrates selected portions of an elevator system 20. The elevator car 22 and counterweight 24 are suspended by a load bearing member 30. The traction between the load bearing member 30 and the traction sheave 26 allows for desired movement of the elevator car 22 in a known manner.

Figure 2 illustrates an end view of an exemplary load bearing member 30 designed according to this invention. In the example of fig. 2, the tension members 32 are encased within a jacket 34 comprising urethane. In the illustrated example, the first layer 36 includes a polymer that in some examples includes urethane (or urethane). Other exemplary polymers include polypropylene and polyethylene. In some examples, the second layer 38 includes urethane. In one example, the first and second layers differ from each other in some way. In another example, the same material is used in both layers.

The illustrated example is a flat belt. The present invention is not limited to a particular geometry or configuration of the load bearing member 30.

One feature of the illustrated example is that the outer surface 40 of the second layer 38 does not include any grooves. In other words, the outer surface 40 is grooveless. This is in contrast to known configurations in which grooves generally perpendicular to the length of the load bearing member 30 are spaced along at least one outer surface of the jacket.

Similarly, the outer surface 42 of the first layer 36 does not have any grooves.

In one example, one or both of the outer surfaces 40 and 42 may be textured or formed to provide, for example, desired frictional characteristics. Generally, a smooth, non-grooved outer surface provides sufficient traction characteristics and avoids noise generation associated with load bearing members that include external grooves on the jacket.

Fig. 3 schematically illustrates a configuration (or arrangement or device) 50 for manufacturing the exemplary embodiment in fig. 2. The forming (or molding) device 52 includes a forming wheel 54. The forming wheel 54 in this example is different from, for example, a conventional forming wheel for producing coated steel strip. While such conventional form wheels have a plurality of bridges for supporting the tension members 32 during the forming process, the surface 55 (fig. 4A) of the form wheel 54 does not have any such bridges. In this example, the outer surface 55 of the forming wheel 54 supports the first layer 36. In one example, the first layer 36 is pre-manufactured and provided from a first layer supply 56, such as a reel. The first layer 36 in this example is pre-fabricated to have a desired width and thickness corresponding to the finished (final) width of the load bearing member 30.

As schematically shown in fig. 4A, the first layer 36 is received within a recess (or well) 58 on the forming wheel 54. In this position, one side 60 of the first layer 36 is facing outward relative to the center of the forming wheel 54.

The tension member 32 is supplied from a supply 64, such as a spool. In one example, a plurality of spools of wire rope are fed into the forming device 52 along with the first layer 36. The first layer 36 is supported on the outer surface 55 of the forming wheel 54 and the tension members 32 are supported on the first layer 36. This is schematically illustrated, for example, in fig. 4B. In this example, the tension member 32 is received against a side 60 of the first layer 36.

In the example of fig. 3, the heater 66 heats the tension members 32 prior to entering the forming device 52. The heated tension members cause at least a portion of the first layer 36 to locally melt in the vicinity of the tension members 32. Such partial melting bonds the tension members 32 to the first layer 36 and provides the desired pull-off strength. Different heater arrangements may be used to increase the temperature of the tension members 32 to meet the needs of a particular situation.

In the example of fig. 3, a supply 70 of urethane material feeds the material into an extruder 72. The urethane material from the supply 70 is then extruded into the molding device 52 to form the second layer 38 within the molding device 52. This is one exemplary method of adding second layer 38 to first layer 36.

Figure 4C schematically illustrates the first layer 36, the tension members 32 and the second layer 38 formed within the forming device 52.

The carrier 30 exits the forming member 52 and is completed in a known manner at a completion station (or location) 76. One example includes a cooling bath for cooling the polymer material of the jacket 34. Any surface texture or dimensional control may be accomplished in a known manner within the completion location 76.

Utilizing the first layer 36 of jacket to support the at least one tension member 32 within the molding apparatus eliminates the need to employ bridges associated with conventional molding techniques for supporting the tension members 32 in the molding apparatus. The elimination of such a bridge eliminates the final recess associated with conventional configurations. Thus, the disclosed example provides the advantage of being able to have an outer jacket 34 of the load bearing member 30 with non-grooved outer surfaces (opposite each other in the case of a flat belt, for example). Having an outer surface without grooves eliminates a significant potential source of noise and vibration in an elevator system.

In one example, the materials selected for first layer 36 and second layer 38 are selected based on the frictional characteristics of these materials. In one example, the different materials are selected so that outer surfaces 40 and 42, respectively, have different frictional characteristics. In another example, at least one material for at least one layer has a different color than the other materials. In yet another example, at least one material selected for at least one of the layers has characteristics that can be used to determine a readily visually inspected technique for the condition of the load bearing member 30 within the elevator system.

The preceding description is exemplary rather than limiting in nature. Variations and modifications to the disclosed examples may become apparent to those skilled in the art that do not necessarily depart from the essence of this invention. The scope of legal protection given to this invention can only be determined by studying the following claims.

Claims (15)

1. A method of making a load bearing member for use in an elevator system, comprising the steps of:

(A) placing at least one tensioning member adjacent one side of a first jacket layer comprising a polymer, the first jacket layer abutting an outer surface of a contoured wheel with a recess; and

(B) subsequently, adding a second jacket layer comprising a polymer at least adjacent to at least one side of the first jacket layer such that the tension members are located between the first and second jacket layers and are at least partially encapsulated within the second jacket layer,

wherein step (B) comprises employing a temperature of at least one of the first or second jacket layers sufficient to cause at least partial melting of at least one of the two layers, thereby bonding the first and second layers together.

2. The method of claim 1, wherein step (a) comprises at least partially melting the first jacket layer in the vicinity of the tension members.

3. The method of claim 2, comprising heating the tension members to a temperature sufficient to cause melting of the first jacket layer in the vicinity of the tension members.

4. The method defined in claim 1 includes heating the tension members prior to the preforming step (a).

5. The method of claim 1, wherein step (B) comprises extruding the second jacket layer onto one side of the first jacket layer.

6. The method of claim 1, wherein step (a) comprises using a pre-formed first jacket layer and supporting the tension members on one side of the first jacket layer.

7. The method of claim 6, wherein step (A) comprises supporting a preformed first jacket layer on the forming wheel with a side of the first jacket layer facing away from the axis of rotation of the forming wheel.

8. The method of claim 1 including employing a plurality of tensioning members.

9. The method of claim 1, wherein the tension member comprises a steel cable.

10. The method of claim 1, wherein the first jacket layer comprises a polymer and the second jacket layer comprises urethane.

11. The method of claim 10, wherein the polymer comprises urethane.

12. The method of claim 11, wherein the first jacket layer urethane is different from the second jacket layer urethane.

13. The method of claim 1, wherein the first jacket layer has a first frictional characteristic and the second jacket layer has a second, different frictional characteristic.

14. The method of claim 1, comprising adding a second jacket layer such that the tension members contact each of the first and second jacket layers.

15. A load bearing member for use in an elevator system comprising at least one tension member generally surrounded by a jacket, the load bearing member being manufactured by the method of any of claims 1-14.