Classifications

• • D—TEXTILES; PAPER
  • D07—ROPES; CABLES OTHER THAN ELECTRIC
  • D07B—ROPES OR CABLES IN GENERAL
  • D07B1/00—Constructional features of ropes or cables
  • D07B1/16—Ropes or cables with an enveloping sheathing or inlays of rubber or plastics
• • D—TEXTILES; PAPER
  • D07—ROPES; CABLES OTHER THAN ELECTRIC
  • D07B—ROPES OR CABLES IN GENERAL
  • D07B1/00—Constructional features of ropes or cables
  • D07B1/005—Composite ropes, i.e. ropes built-up from fibrous or filamentary material and metal wires
• • D—TEXTILES; PAPER
  • D07—ROPES; CABLES OTHER THAN ELECTRIC
  • D07B—ROPES OR CABLES IN GENERAL
  • D07B1/00—Constructional features of ropes or cables
  • D07B1/22—Flat or flat-sided ropes; Sets of ropes consisting of a series of parallel ropes
• • D—TEXTILES; PAPER
  • D07—ROPES; CABLES OTHER THAN ELECTRIC
  • D07B—ROPES OR CABLES IN GENERAL
  • D07B2201/00—Ropes or cables
  • D07B2201/20—Rope or cable components
  • D07B2201/2083—Jackets or coverings
  • D07B2201/2087—Jackets or coverings being of the coated type
• • D—TEXTILES; PAPER
  • D07—ROPES; CABLES OTHER THAN ELECTRIC
  • D07B—ROPES OR CABLES IN GENERAL
  • D07B2501/00—Application field
  • D07B2501/20—Application field related to ropes or cables
  • D07B2501/2007—Elevators

Definitions

• the present invention relates to elevator systems, and more particularly to tension members for such elevator systems.
• a conventional traction elevator system includes a car, a counterweight, two or more ropes interconnecting the car and counterweight, a traction sheave to move the ropes, and a machine to rotate the traction sheave.
• the ropes are formed from laid or twisted steel wire and the sheave is formed from cast iron.
• the machine may be either a geared or gearless machine.
• a geared machine permits the use of higher speed motor, which is more compact and less costly, but requires additional maintenance and space.
• a principal feature of the present invention is the flatness of the tension member.
• the increase in aspect ratio results in a tension member that has an engagement surface, defined by the width dimension, that is optimized to distribute the rope pressure. Therefore, the maximum pressure is minimized within the tension member.
• the thickness of the tension member may be reduced while maintaining a constant cross-sectional area of the tension member.
• the tension member includes a plurality of individual load carrying cords, strands and/or wires encased within a common layer of coating.
• the coating layer separates the individual cords, strands and/or wires and defines an engagement surface for engaging a traction sheave.
• the rope pressure may be distributed more uniformly throughout the tension member.
• the maximum rope pressure is significantly reduced as compared to a conventionally roped elevator having a similar load carrying capacity.
• the effective rope diameter 'd' (measured in the bending direction) is reduced for the equivalent load bearing capacity. Therefore, smaller values for the sheave diameter 'D' may be attained without a reduction in the D/d ratio.
• minimizing the diameter D of the sheave permits the use of less costly, more compact, high speed motors as the drive machine without the need for a gearbox.
• the cords, strands and/or wires in the tension member of the invention are preferably steel and organic fiber in a number of combinations.
• the two materials may be maintained separately and comprise distinct steel cords and organic fiber cords in the common jacket; the two materials may be combined into a single cord, a plurality of which cords are dispersed in the common jacket; the materials may be wrapped one around the other in ordered arrays within the common jacket; and the organic fibers may be randomly dispersed in the common jacket with steel cords being also dispersed therein.
• Each of the combinations noted provides a hybrid flexible flat tension member having strengths and advantages not available in steel cord flat tension members or organic fiber flat tension members. Advantages of each material individually include for steel: nondestructive examination capabilities; high heat resistance; low stretch.
• the present invention provides several embodiments which allow the two materials to "share-the-load" which requires consideration of load carrying capability of each of the types of material; the long term bending fatigue resistance of the individual materials; the stretch of each material and belt tracking stability achieve such synergistic benefits.
• FIGURE 1 is perspective view of an elevator system having a traction drive within which the tension member of the invention functions;
• FIGURE 2 is a schematic cross section of a first embodiment of a hybrid flexible flat tension member of the invention
• FIGURE 3 is a schematic cross section of a second embodiment of a hybrid flexible flat tension member of the invention
• FIGURE 4 is a schematic cross section of a third embodiment of a hybrid flexible flat tension member of the invention.
• FIGURE 5 is a schematic cross section of a fourth embodiment of a hybrid flexible flat tension member of the invention.
• FIGURE 6 is a graphic representation of elastic modulus of a tension member of the invention.
• FIGURE 7 is a graphic representation of strength of a tension member of the invention.
• FIGURE 1 Illustrated in FIGURE 1 is a traction elevator system 12.
• the elevator system 12 includes a car 14, a counterweight 16, a traction drive 18, and a machine 20.
• the traction drive 18 includes a tension member 22, interconnecting the car 14 and counterweight 16, and a traction sheave 24.
• the tension member 22 is engaged with the sheave 24 such that rotation of the sheave 24 moves the tension member 22, and thereby the car 14 and counterweight 16.
• the machine 20 is engaged with the sheave 24 to rotate the sheave 24.
• geared machine 20 Although shown as a geared machine 20, it should be noted that this configuration is for illustrative purposes only, and the present invention may be used with geared or gearless machines.
• the invention provides hybrid material flexible flat tension members having superior properties to single material flexible flat tension members. It should be noted that all possible mixtures of the load carrying material do not provide a synergistic result in the tension member created. Rather, careful analysis of structural load carrying capacity is required to balance the load applied between the types of load carrying materials and obtain superior characteristics as well as excellent tension member tracking stability.
• FIGURE 2 a first embodiment of a hybrid flexible flat tension member of the invention is illustrated schematically in cross section.
• Tension member 22 comprises a common urethane or other polymeric jacket 26. Steel load carrying material is located in areas marked 28 while organic load carrying material is identified as 30. As one of ordinary skill in the art will appreciate the load carrying material is relatively evenly spaced over the width of tension member 22.
• the organic fibers 30 are illustrated as having a larger cross section than the steel cords 28 but this is not required. Rather the question is what weight rating is desired and what heat resistance is desired as well as similar parameters.
• Mathematical calculation which is within the level of skill of one of ordinary skill in the art to conduct, is then carried out to determine the amount of organic fiber to be used and the amount of steel cord to be used. The calculations are employed to ensure that the load will be shared among the various cords in the flat tension member allowing the benefits and properties of each to be utilized. It is also important that the axial stiffness of the tension member be such that at any given applied load, both types of cords share in the elastic response of the tension member. The twist and construction of these two cord types can be chosen to enable this load sharing.
• the cords themselves are not restricted in size, number or distribution (other than for tracking) to enable this result nor is it required that an equal number of organic fiber cords and steel cords be employed. What is important is that the characteristics of the two cord types be balanced with respect to the desired properties of the tension member so that those desired properties may be achieved. More than one way of laying out the cords and dimensions, etc. is possible for each desired result. It is noted that distribution is important to facilitate a tracking aspect of the tension member and one of the more easily accomplished distribution schemes for proper tracking is an even distribution of cord types across an axial centerline of the tension member.
• One parameter that it is preferred to control is bending. It is preferable for steel cords to fail before organic cords in bending so that nondestructive examination methods may be employed to determine the integrity of the tension member. Such methods include electrical resistance or magnetic flux leakage.
• each cord of the tension member 22 is hybrid in nature. Depicted is a tension member in cross section where an organic fiber material is located in an annulus 32 around a core 34 of steel. Although the tension member is illustrated with material types only one way it is to be understood that the organic fiber material may make up the core while steel is used for the annulus. It should also be appreciated that all of the cords used in the embodiment need not employ the same core material. One or more of the cords may employ steel as core 34 while one or more other cords may employ organic fiber as core 34. The twist and construction of each cord at the level of the annulus and the level of the core will affect the properties of the total tension member and this must be taken into account.
• each cord 38 is composed of several strands e.g. nine (eight around one) and each strand is hybrid in nature.
• the strands 40 in the drawing are illustrated as having an organic center wire 42 and eight steel wires 44 positioned therearound. Six of these strands are then positioned around a center strand 46 to form a hybrid cord 38. It will be understood that the positioning of the steel wires 44 and the organic fibers 42 could be reversed. Similar calculations must be made for this embodiment as are noted in the foregoing embodiments, such calculations being within the level of skill of the ordinary skilled artisan.
• Hybrid cords are also beneficial in that the particular makeup of the cords can vary for specific purposes. For example, where a crowned sheave (not shown) will be used with a particular elevator system with which the tension member will be used to improve tracking, the cords that ride near or directly over the crown will be loaded more highly than other cords in the tension member.
• the hybrid cords can be tailored to handle the higher loading. Referring now to figure 5, yet another embodiment of the invention is illustrated. Figure 5 is an enlarged view showing only two cords. It will be understood that the embodiment may contain more cords.
• steel cords 50 having preferably seven wires each in a pattern of six around one are provided by themselves and are not directly hybrid cords.
• the tension member 22 is hybrid as it includes, in the common coating material 28 which surrounds the cords, individual organic fibers 52. Fibers 52 are preferably oriented in parallel to the tension member major axis and are distributed throughout material 28.
• the stiffness of the steel cords 50 of this embodiment is controlled by the stiffness of the steel wires while organic fibers provide their own stiffness.
• Material 28 in this embodiment is preferably, as it is in the foregoing embodiments, composed of polyurethane.
• the elastic modulus of the tension member can be increased by increasing the volume percent of steel used therein.
• modulus calculations are based upon the "rule of mixtures", to wit:
• E i l o fiber 2 longitudinal modulus
• E m matrix modulus
• V f i volume percent fiber 1
• V ⁇ volume percent fiber 2
• V m volume percent matrix 3 the change in elastic modulus is seen graphically in figure 6.
• a calculation of the tensile strength of an exemplary tension member of the invention as a function of steel/organic fiber (e.g. Kevlar) content within the common coating of the tension member, i.e. the polyurethane coating in a preferred embodiment, is illustrated graphically in figure 7 where the volume percent of steel/Kevlar to the common coating material is maintained at 60 v/o (volume percent) but the percentage of steel and Kevlar relative to each other is varied.
• steel/organic fiber e.g. Kevlar
• V s ( ⁇ k / ⁇ s ) V k

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• Ropes Or Cables (AREA)
• Lift-Guide Devices, And Elevator Ropes And Cables (AREA)

Priority Applications (4)

Applications Claiming Priority (2)

Publications (1)

Family

ID=22536389

Family Applications (1)

Country Status (8)

Cited By (19)

Families Citing this family (16)

Citations (5)

Family Cites Families (11)

• 2000
  • 2000-08-21 CN CNB008118310A patent/CN1188567C/zh not_active Expired - Lifetime
  • 2000-08-21 DE DE60015771T patent/DE60015771T2/de not_active Expired - Lifetime
  • 2000-08-21 KR KR1020027001732A patent/KR100697742B1/ko not_active IP Right Cessation
  • 2000-08-21 WO PCT/US2000/022943 patent/WO2001014630A1/en active IP Right Grant
  • 2000-08-21 ES ES00957636T patent/ES2231242T3/es not_active Expired - Lifetime
  • 2000-08-21 JP JP2001518494A patent/JP4832689B2/ja not_active Expired - Fee Related
  • 2000-08-21 BR BRPI0013514-3A patent/BR0013514B1/pt not_active IP Right Cessation
  • 2000-08-21 EP EP00957636A patent/EP1208265B1/de not_active Expired - Lifetime

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