Abstract:
A sway reduction device having a cable receiving section, the cable receiving section being formed of a shock-absorbing material and comprising a flexure portion and an aperture for receiving a cable therethrough. The sway reduction device also includes a mounting section with subsections and at least one mounting member for mounting the sway reduction device to a surface. The subsections are moveable generally toward and away from each other whereby the flexure portion is flexed when the subsections are moved away from each other for installing the sway reduction device around a cable.

Description:
FIELD OF THE INVENTION 
     The present invention relates to a sway reduction device for use with a cable, and more particularly, for use with an elevator compensating cable. 
     BACKGROUND OF THE INVENTION 
     Elevator hoistways typically include at least one elevator cable that supports and moves an elevator car and counterweight during operation of the car. The elevator compensating cable can be installed through a sway reduction device designed to dampen oscillations or cable swaying motion as the car and counterweight are moved. 
     An example of a known dampening device is the Whisper-Flex® Dampening Device (WFDD) made commercially available by Republic Wire &amp; Cable of Rocky Mount, N.C., USA. The WFDD includes a series of wear resistant and flame retardant rollers that are disposed on four sides of the cable. The rollers are rotatably mounted to a metal frame by sealed bearings and brackets. A typical WFDD assembly can consume over 200 cubic inches of space. During installation, four mounting holes each receive a respective mounting bolt for mounting the assembly to a stationary surface, for example, an elevator rail or support beam in an elevator hoistway. 
     The WFDD successfully performs the sway dampening function but it may have some disadvantages, for example, manufacturing the device can be expensive and installation can be difficult. More particularly, assembly of the WFDD can be a time consuming procedure. In addition, the size and weight of the WFDD assembly can make installation difficult in a crowded elevator hoistway. 
     OBJECTS OF THE INVENTION 
     It is an object of the present invention to provide a sway reduction device for receiving a cable, comprising a cable receiving section, the cable receiving section comprising a wall defining an aperture for receiving a cable therethrough; and a mounting section, the mounting section being formed of a flexible, shock absorbing substance and comprising mounting members for mounting the sway reduction device to a surface, when the cable impacts the wall, the mounting section is operative to at least partially absorb the shock of the impact. 
     It is an object of the present invention to provide a sway reduction device comprising a cable receiving section, the cable receiving section being formed of a shock-absorbing material and comprising a flexure portion and an aperture for receiving a cable therethrough; and a mounting section, the mounting section comprising subsections and at least one mounting member for mounting the sway reduction device to a surface; the subsections being moveable generally toward and away from each other whereby the flexure portion is flexed when the subsections are moved away from each other for installing the sway reduction device around a cable. 
     It is an object of the present invention to provide an elevator system comprising an elevator car, an elevator compensating cable attached to a support bracket, and a safety support, the elevator compensating cable passing through at least one sway reduction device and is attached to a counterweight and the elevator car, the elevator cable comprising a substantial mass of material, when the elevator cable is moved during operation of the elevator system the cable impacting a wall of the sway reduction device, the sway reduction device comprising a shock absorbent mounting section that is flexible and operative to dampen the impact, at least partially absorbing and dissipating the energy transmitted from impact with the cable. 
    
    
     BRIEF DESCRIPTION OF THE DRAWING FIGURES 
     FIG. 1 is an isometric view of a sway reduction device according to the present invention with a compensating cable passing through it. 
     FIG. 2 is top view of the sway reduction device of FIG.  1 . 
     FIG. 3 is side view of the sway reduction device of FIG.  1 . 
     FIG. 4 is a side view of the sway reduction device of the present invention in a flexed state for accommodating installation thereof with an existing cable. 
     FIG. 5 is a cross sectional view of the sway reduction device of FIG. 2 taken at line  5 — 5 . 
     FIG. 6 is a cross sectional view of an alternative embodiment of the sway reduction device of the present invention. 
     FIG. 7 is a schematic view of an elevator system including sway reduction devices according to the present invention. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     With reference to FIGS. 1-5, embodiments of a sway reduction device  10  according to the present invention will be described. Sway reduction device  10  comprises a mounting section  12  and a cable passage section  20 . Mounting section  12  comprises at least two subsections  13  divided by a slit  17 . Each subsection  13  can include at least one mounting member, for example, mounting bolts  14  as shown for example in FIG.  2 . Subsections  13  can be connected by a connecting member, for example, a hex-head connecting bolt  16 . Connecting bolt  16  can be inserted into respective bores  15  formed in subsections  13 , e.g., as shown in FIG.  2 . At least one of bores  15  can be formed with a hex-shaped countersunk hole for receiving the hex head of connecting bolt  16 . Slit  17  can be a generally planar interface between facing sides of subsections  13  that generally bisects mounting section  12 . Slit  17  can be generally medially disposed between edges of sway reduction device  10 , or it may be offset to one side (not shown). In addition, slit  17  may have a generally flat shape between subsections  13 , or it may comprise arcuate shapes or a combination of flat and arcuate shapes (not shown). 
     Cable passage section  20  comprises an outer surface, for example, a semi-cylindrical outer surface  21 . Cable passage section  20  also includes a flexure portion  24  (FIG. 1) for flexing when subsections  13  are moved away from each other (FIG.  4 ). Cable passage section  20  includes a cable passage through which a cable can pass, for example, an elevator compensating cable  50  (FIG.  1 ). The aperture is defined by a through-extending, generally annular and smooth wall  22 . Wall  22  may include a profile with arcuate portions that can be defined by a constant or varying radius of curvature. For example, wall  22  may comprise an hour-glass like profile as viewed in a cross section (FIGS.  5 - 6 ). The profile may comprise a constant radius of curvature R, and/or generally parabolic arcs having a varying radius of curvature. Alternatively, wall  22  may be generally cylindrical, or it may be a combination of generally cylindrical and arcuate portions. 
     Sway reduction device  10  presents a compact design. For example, the length L, width W, and height H of device  10  (FIG. 1) can be about 6, 4, and 3 inches, respectively. In other words, sway reduction device  10  can consume a volume of roughly about 72 cubic inches of space in an elevator hoistway. In addition, the present invention includes embodiments that minimize the volume of material required to manufacture device  10 . For example, the corners of sections  12 , 20  can be tapered to reduce the volume of potentially costly thermoplastic material (FIG.  3 ). 
     Sway reduction device  10  can include a friction guard  23  (FIG. 6) formed of, for example, any suitable non-metallic material. Friction guard  23  is preferably a split ring that is removably attached to a recess formed in wall  22  so that if it becomes worn it can be easily replaced. Friction guard  23  can comprise a low-friction substance, for example, NYLON, TEFLON, a silicone additive, or a highly polished resilient metallic material, e.g., brass. Friction guard  23  can also be a composite of a non-metallic and metallic materials, for example, a metal ring coated with a suitable thermoplastic. Moreover, friction guard  23  can be a foamed substance, e.g., foamed polyurethane. 
     Manufacture of sway reduction device  10  can be accomplished in a molding process, for example, in a casting or injection molding process. Mounting section  12  and cable passage section  20  are preferably monolithically formed. A suitable thermoplastic rubber material with suitable mechanical properties can be used, for example, polyurethane with a Shore D hardness of 50-65. The mold can be an aluminum mold with a smooth finish. The mold should support mounting bolts  16 , and can include parts that will define, for example, wall  22 , slit  17 , and bores  15 . Sway reduction device  10  can be formed of any suitable moldable material that exhibits low friction, wear and impact resistance, and suitable flexibility and shock absorbing properties. For example, sway reduction device  10  can include a thermoplastic rubber other than polyurethane, a thermoset, or other suitable moldable material. Alternatively, the moldable material may comprise a thermoplastic elastomer, e.g., a block copolymer such as KRATON. The moldable material may include a flame retardant additive, and/or an inert filler, for example, fumed silica, glass beads, and/or microspheres. Additionally, the moldable material can be foamed mechanically and/or foamed with a chemical foaming agent. The moldable material may also include a noncompatible additive, for example silicone, that can migrate to the surface of wall  22  for reducing friction between sway reduction device  10  and the jacket of an elevator compensating cable. Moreover, the mold can be modified to reduce the amount of moldable material required, for example, outer surfaces can be tapered from cable passage section  20  toward mounting bolts  14  (FIG.  3 ). 
     Sway reduction device  10  can be installed in an exemplary elevator system  60  shown schematically in FIG.  7 . Elevator system  60  includes an elevator car  61 , and an elevator compensating cable  50  attached to a support bracket  62  and a safety support  63 . Compensating cable  50  passes through two sway reduction devices  10  and is attached to a counterweight support bracket  65  and a counterweight  66 . In an exemplary installation procedure, sway reduction device  10  can be installed about an existing cable  50  by separating subsections  13  and flexing flexure portion  24  so that slit  17  is opened wide enough to permit cable  50  to be received in cable receiving section  20  (FIG.  4 ). Slit  17  is then closed, mounting bolts  14  are fastened to a surface, and connecting bolt  16  is fastened so that subsections  13  are held firmly together. At this point, sway reduction device is firmly mounted and is ready to be impacted by the mass of cable  50 . A typical elevator compensating cable  50  is a substantial mass—it can include a heavy metal chain embedded in a thermoplastic, metal filler beads, and a durable outer jacket of thermoplastic. When cable  50  is moved during normal operation of system  60 , this mass of cable may sway and may repeatedly impact walls  22  of sway reduction devices  10 . 
     Sway reduction device  10  acts as a cushion in that it at least partially absorbs and dissipates the energy transmitted from impact with the heavy mass of cable  50 . This cushioning occurs because at least one of sections  12 , 20 , but preferably both sections, is formed of a flexible, shock absorbent and moldable material that can function as a flexible spring and a shock absorber. This can be analogous to a typical spring, mass, damper system for at least partially dissipating energy generated by a force acting on the mass. Mounting section  12  and/or cable receiving section  12  can function as a spring, due to flexibility of the moldable material, and as a damper, due to the inherent ability of the moldable material to cushion/dissipate impact forces. 
     The present invention has thus been described with reference to the exemplary embodiments, which embodiments are intended to be illustrative of the present inventive concepts rather than limiting. Persons of ordinary skill in the art will appreciate that variations and modifications of the foregoing embodiments may be made without departing from the scope of the appended claims. For example, the mounting and connecting members can comprise, latching structures including linearly and/or rotatably acting cam locking surfaces and/or latch arms. Mounting members may also comprise such mounting components as, for example, U-bolts, plates, brackets, angle iron, and/or stamped metal parts. The aperture defined by wall  22  can be a non-annular shape, for example, oval, elliptical, rectangular, square, etc. If an oval slope shape is used, a two-piece friction guard can be used with respective pieces located at ends of the oval with one piece having a function of fastening subsections  13  together thereby obviating the need for connecting member  16 . Furthermore, the cable receiving section may include movable, e.g. rotatable, parts for engaging the cable.