Method and an apparatus for twisting and tightening a wire

Abstract

A method and apparatus for twisting and tightening a wire with a free end portion around at least two objects, e.g. iron bars for reinforced concrete, for binding the objects together. The method and apparatus enables a tighter and stronger binding to be performed even by means of a portable device and with the use of less binding wire than required by conventional devices.

1 . A method for twisting and tightening a wire with a free end portion around at least two objects for binding the objects together, the method comprising: 
 arranging the two objects in close contact,    placing a twisting member in a position next to the objects, the twisting member having a surface facing the objects,    guiding the free end portion through a hole or groove in the twisting member,    guiding the free end portion in a path at least one time around the objects, so as to wind a wire portion in at least one loop around the objects,    guiding the free end portion through or into the twisting member whereby the wire forms a closed loop and defines an intersection of two wire portions, so that said surface of the twisting member is between the intersection and the objects,    gripping the end of the free end portion of the wire,    tightening the wire by pulling,    turning the twisting member, so as to twist the wire, characterised in that the wire is cut by a cutting edge of the twisting member.    
     
     
         2 . An apparatus ( 1 ) for twisting and tightening a wire around two objects and comprising: 
 a twisting member ( 9 )( 44 ) having a surface ( 64 ) facing the objects, the twisting member being mounted in such a way that said surface may contact or be in close contact with the two objects,    two jaws ( 7 ) adapted to encircle the two objects, the jaws being arranged opposite to each other and facing each other in a loop-shaped configuration, each of the jaws having one free end portion and one end pivotally mounted near the twisting member,    power-driven means ( 17 ) for feeding a wire through a first hole ( 53 ) in the twisting member and along guiding means ( 56   a , 58 ) In a first one of the two jaws to the free end portion of that jaw and further to the free end portion of the second jaw and therefrom along guiding means ( 56   b , 58 ) in the second jaw and further through a second hole ( 53 ) In the twisting member, so as to wind a portion of the wire at least one time around the objects; whereby the wire forms a loop and defines an intersection ( 28 ) of two wire portions, so that said surface of the twisting member is between the intersection and the objects,    gripping means ( 36 ,  61 ) for gripping a free end portion of the wire when the wire has been fed around the objects,    tightening means ( 29 ) for tightening the wire when gripped by the gripping means,    power-driven means ( 12 ) for rotating the twisting member, so as to twist two portions of the tightened wire around each other, characterised in that the twisting member defines a cutting edge which is adapted to cut the wire when the twisting member is rotated.    
     
     
         3 . An apparatus according to  claim 2 , wherein the jaws are provided with a non-circular shape.  
     
     
         4 . An apparatus according to claim  2 - 3 , wherein the means for feeding the wire comprises an electrically driven motor.  
     
     
         5 . An apparatus according to any of claims  2 - 4 , wherein the means for rotating the twisting member comprises an electrically driven motor.  
     
     
         6 . An apparatus according to any of claims  2 - 3  or  5 , wherein the means for feeding the wire comprises pneumatically driven means.  
     
     
         7 . An apparatus according to any of claims  2 - 4  or  9 , wherein the means for rotating the twisting member comprises pneumatically driven means.  
     
     
         8 . An apparatus according to any of claims  2 - 3  or  5  or  7 , wherein the means for feeding the wire comprises hydraulically driven means.  
     
     
         9 . An apparatus according to any of claims  2 - 3  or  6  or  8 , wherein the means for rotating the twisting member comprises hydraulically driven means.  
     
     
         10 . An apparatus according to any of claims  2 - 11 , wherein the same electrically driven motor is used for twisting and feeding.  
     
     
         11 . An apparatus according to any of claims  2 - 3  or  6 - 7 , wherein the same pneumatically riven motor is used for twisting and feeding.  
     
     
         12 . An apparatus according to any of claims  2 - 3  or  8 - 9 , wherein the same hydraulically riven motor is used for twisting and feeding.  
     
     
         13 . An apparatus according to any of claims  2 - 12 , wherein the gripping means comprises echanical or electromechanical actuation means and wherein the mechanical or electroechanical actuation means is selected from a group comprising: 
 electromagnets,    hydraulic actuators,    pneumatic actuators.    
     
     
         14 . An apparatus according to any of claims  2 - 13 , wherein the operation of the first and/or the second electrically, pneumatically or hydraulically driven motor is being controlled by a control system.  
     
     
         15 . An apparatus according to  claim 14 , wherein the control system is comprised in means or electronically processing such as a CPU.  
     
     
         16 . An apparatus according to  claim 15 , further comprising a display connected to the CPU for displaying information to the user.  
     
     
         17 . An apparatus according to  claim 15  or  16 , further comprising an interface for communication between the CPU and external processing means.  
     
     
         18 . An apparatus, according to claim  15 - 17 , wherein the means for electronically processing are adapted to vary the tightening force in correspondence to a user-selectidn.  
     
     
         19 . An apparatus according to any of claims  2 - 1 - 8 , wherein at least the part of the twisting member which faces the objects is made of a hardened steel alloy such as titanium alloys or similar metallic or ceramnic materials.  
     
     
         20 . A apparatus according to any of claims  2 - 19 , wherein each of the free end portions of the jaws forms a funnel-shaped opening extending away from the contact between the free end portions of the two jaws.  
     
     
         21 . An apparatus according to any of claims  2 - 20 , wherein the jaws are spring-biased towards a closed position.  
     
     
         22 . An apparatus according to any of claims  2 - 20 , wherein the jaws are closed by hydraulic, pneumatic or electrically driven means.  
     
     
         23 . An apparatus according to  claim 22 , wherein the closing by hydraulic, pneumatic or electrically driven means is controlled by the CPU.  
     
     
         24 . An apparatus according to any of claims  2 - 23 , wherein a carrying support arm can be attached to the housing of the apparatus for carrying the weight of the apparatus and to enable. the apparatus to be used in a distance from the hands of the operator.  
     
     
         25 . An apparatus according to any of claims  2 - 24 , further comprising a contact face for supporting the apparatus against the objects.  
     
     
         26 . An apparatus according to any of claims  2 - 25 , wherein the wive is an elastic wire for binding an object, said wire having an elasticity of at least 50,000 MPa.  
     
     
         27 . An apparatus according to  claim 26 , wherein the wire is made from an iron alloy comprises in the range of 1.2-2.0% manganese (Mg), 0.8-1.2% silicon (Si) and 0.06-0, 15% carbon (C).