Wedge clamp type termination for elevator tension member

Abstract

A tension member termination device optimized for terminating flat tension members having compressible outer coatings, the device including a wedge and a socket each having cooperating surfaces positioned at a predetermined angle for clamping the tension member therebetween. The angle reliably secures the tension member while avoiding deleterious pressure and stress upon the tension member. The invention also provides a safety clamp for optional use with the tension member termination device.

What is claimed is: 
     
       1. A termination device for a tension member, the tension member having a width W and an elastomer coating that has a maximum compressive stress capability σ c , the tension member being subjected to a tensile force T, the termination device comprising:
 a socket; and 
 a wedge that fits within the socket with the tension member wrapped around the wedge, the wedge having a clamping surface that includes a length L and is disposed at an angle ϕ, which is measured from a centerline of the wedge to the clamping surface and which relates to the length L in accordance with the formula defining a minimum of the angle ϕ:
   ϕ≥tan −1  ϕ=tan −1 (T/(σ c *L*W)).
 
 
 
     
     
       2. A method for terminating a tension member having a width W and an elastomer coating that has a maximum compressive stress capability σ c , comprising:
 feeding the tension member into an aperture of a socket; 
 wrapping the tension member around a wedge having a clamping surface that includes a length L and is disposed at an angle ϕ, which is measured from a centerline of the wedge to the clamping surface; 
 feeding the tension member back through the aperture; and 
 applying a tensile force T in the tension member so that the tension member is compressed between the wedge and the socket, wherein the tensile force T is applied in accordance with the formula defining a minimum of the angle ϕ:
   ϕ≥tan −1  ϕ=tan −1 (T/(σ c *L*W)).
 
 
 
     
     
       3. A method according to  claim 2  further comprising:
 positioning the tension member in a back-to-back arrangement; 
 placing a pair of plates on either side of the tension member; 
 inserting a plurality of fasteners through the plates; 
 tightening the fasteners; and 
 clamping the tension member between the plates in a double overlap arrangement. 
 
     
     
       4. A termination device for a tension member, the tension member having a width W and a compressible coating that has a predetermined maximum compressive stress capability σ c , the compressible coating being subject to compressive creep, the tension member being subjected to a tensile force T, the termination device comprising:
 a socket; and 
 a wedge that fits within the socket with the tension member wrapped around the wedge, the wedge having a clamping surface that includes a length L and is disposed at an angle ϕ, which is measured from a centerline of the wedge to the clamping surface and which relates to the length L in accordance with the formula defining a minimum of the angle ϕ:
   ϕ=tan −1 (T/(σ c *L*W)). 
 
 
 
     
     
       5. A method for terminating a tension member having a width W and a compressible coating that has a predetermined maximum compressive stress capability σ c , the compressible coating being subject to compressive creep, the method comprising:
 feeding the tension member into an aperture of a socket; 
 wrapping the tension member around a wedge having a clamping surface that includes a length L and is disposed at an angle ϕ, which is measured between a centerline of the wedge and the clamping surface; 
 feeding the tension member back through the aperture; and 
 applying a tensile force T in the tension member so that the tension member is compressed between the wedge and the socket, wherein the tensile force T is applied in accordance with the formula defining a minimum of the angle ϕ:
   ϕ=tan −1 (T/(σ c *L*W)). 
 
 
 
     
     
       6. A termination device for a tension member, the tension member having a width W and comprised of a plurality of inner load carrying cords and a compressible coating, wherein the compressible coating defines a traction surface for the tension member and the compressible coating has a predetermined maximum compressive stress capability σ c , the compressible coating being subject to compressive creep if the maximum compressive stress capability is exceeded, the tension member being subjected to a tensile force T, the termination device comprising:
 a socket; and 
 a wedge that fits within the socket with the tension member wrapped around the wedge, the wedge having a clamping surface that includes a length L and is disposed at an angle ϕ, which is measured between a centerline of the wedge and the clamping surface and which relates to the length L in accordance with the formula that defines a minimum of the angle ϕ:
   ϕ=tan −1 (T/(σ c *L*W)). 
 
 
 
     
     
       7. A method for terminating a tension member having a width W and comprised of a plurality of inner load carrying cords and a compressible coating, wherein the compressible coating defines a traction surface for the tension member and has a predetermined maximum compressive stress capability σ c , the compressible coating being subject to compressive creep if the predetermined maximum compressive stress capability is exceeded, the method comprising:
 feeding the tension member into an aperture of a socket; 
 wrapping the tension member around a wedge having a clamping surface that includes a length L and is disposed at an angle ϕ, which is measured between a centerline of the wedge and the clamping surface; 
 feeding the tension member back through the aperture; and applying a tensile force T in the tension member so that the tension member is compressed between the wedge and the socket, wherein the tensile force T is applied in accordance with the formula that defines a minimum of the angle ϕ:
   ϕ=tan −1 (T/(σ c *L*W)).