Wire twisting apparatus

Abstract

A rotatable member ( 105 ) has an aperture ( 115 ) substantially aligned with an axis of rotation of the member and through which a first length of wire ( 2 a ) may extend. A recess ( 117 ) is provided in the member. An engagement surface ( 131 ) is associated with the recess. With s first length of wire ( 2 a ) extending through the aperture and a second length of wire ( 7 ) extending across and adjacent to the first length of wire, rotation of the rotatable member will cause the engagement surface ( 131 ) to engage with the second length of wire ( 7 ) and twist the second length of wire around the first length of wire ( 2 a ) to form a twisted wire joint at least substantially within the recess and which includes a plurality of full turns of the second length of wire around the first length of wire.

1 . An apparatus for twisting a second length of wire around a first length of wire to form a twisted wire joint, the apparatus comprising a rotatable member comprising:
 an aperture substantially aligned with an axis of rotation of the member and through which a first length of wire may extend;   a recess, at least a portion of which is substantially aligned with the aperture; and   an engagement surface associated with the recess;   wherein the apparatus is configured such that with a first length of wire extending through the aperture and a second length of wire extending across and adjacent to the first length of wire, rotation of the rotatable member will cause the engagement surface to engage with the second length of wire and twist the second length of wire around the first length of wire to form a twisted wire joint at least substantially within the recess and which includes a plurality of full turns of the second length of wire around the first length of wire.   
   
   
       2 . An apparatus as claimed in  claim 1 , wherein the apparatus is configured to form the twisted wire joint while allowing a remainder part of the second length of wire, other than the part in the twisted wire joint, to remain substantially undeformed. 
   
   
       3 . An apparatus as claimed in  claim 2 , wherein the apparatus does not require movement of the rotatable member along the first length of wire during the formation of the twisted wire joint or movement of the remainder part of the second length of wire along the first length of wire during the formation of the twisted wire joint. 
   
   
       4 . An apparatus as claimed in  claim 1 , wherein the engagement surface is configured to direct a free end of the second length of wire in the general direction of the aperture, during the formation of the twisted wire joint. 
   
   
       5 . An apparatus as claimed in  claim 4 , configured such that the second length of wire will have an initial point of contact with the first length of wire prior to, or as, the rotatable member is rotated, and wherein the second length of wire can substantially maintain its initial point of contact with the first length of wire during the formation of the twisted wire joint, and the twisted wire joint will extend into the recess from the initial point of contact between the first and second lengths of wire. 
   
   
       6 . An apparatus as claimed in  claim 5 , wherein the recess terminates at a substantially planar surface of the rotatable member, and wherein a portion of the remainder part of the second length of wire can remain substantially in contact with the generally planar surface during formation of the twisted wire joint. 
   
   
       7 . Art apparatus as claimed in  claim 4 , wherein the engagement surface is angled and extends substantially from an outer edge of the rotatable member toward the aperture in the rotatable member. 
   
   
       8 . An apparatus as claimed in  claim 7 , wherein the outer edge of the rotatable member defines an engagement portion to initially engage with the second length of wire upon rotation of the rotatable member. 
   
   
       9 . An apparatus as claimed in  claim 1 , wherein the recess comprises a generally centrally-disposed arcuate wall portion that is positioned adjacent the aperture. 
   
   
       10 . An apparatus as claimed in  claim 9 , wherein the aperture has a diameter, and the arcuate wall portion has a size sufficiently greater than the diameter of the aperture that the portion of the first wire extending through the aperture is supported during the formation of the twisted wire joint, and sufficient clearance is provided in the arcuate wall portion to enable the twisted wire joint to be formed. 
   
   
       11 . An apparatus as claimed in  claim 9 , wherein the recess is generally segment-shaped, and wherein a narrow portion of the generally segment-shaped recess is defined by the arcuate portion. 
   
   
       12 . An apparatus as claimed in  claim 1 , wherein, the engagement surface is defined by a wall portion of the recess. 
   
   
       13 . An apparatus as claimed in  claim 1 , comprising a positioning member configured to position a free end of the second length of wire such that rotation of the rotatable member will cause the engagement surface of the rotatable member to engage with the second length of wire. 
   
   
       14 . An apparatus as claimed in  claim 13 , wherein the positioning member is configured to bend a free end of the second length of wire extending beyond a central portion of the rotatable member. 
   
   
       15 . An apparatus as claimed in  claim 13 , wherein the positioning member comprises a ramp portion that is configured to bend the free end of the second length of wire upon relative movement between the free end of the second length of wire and the positioning member. 
   
   
       16 . An apparatus as claimed in  claim 1 , comprising a cutting member to cut a free end of the second length of wire prior to rotation of the rotatable member. 
   
   
       17 . An apparatus as claimed in  claim 1 , further comprising at least one support plate to assist in maintaining the wires adjacent one another during the formation of the twisted wire joint. 
   
   
       18 . An apparatus as claimed in  claim 17 , wherein the support plate comprises a curved portion to assist in directing a free end of the second length of wire in the general direction of the aperture, upon rotation of the rotatable member. 
   
   
       19 . An apparatus as claimed in  claim 1 , configured such that the first length of wire remains substantially undeformed during the formation of the twisted wire joint. 
   
   
       20 . A fence mesh forming machine comprising:
 a machine bed arranged to pass a plurality of substantially parallel line wires therethrough;   an apparatus arranged to deliver a stay wire across the line wires; and   an apparatus as claimed in  claim 1  arranged to twist a free end of the stay wire around one of the line wires to form a twisted wire joint.   
   
   
       21 . A fence mesh, forming machine as claimed in  claim 20 , wherein, the apparatus is arranged to twist the free end of the stay wire around an outermost line wire of the plurality of line wires. 
   
   
       22 . A fence mesh, forming machine as claimed in  claim 20 , comprising two apparatuses as claimed in  claim 1 , arranged to twist the free ends of the stay wire around the two outermost line wires of the plurality of line wires to form twisted wire joints. 
   
   
       23 . A method of twisting a second length of wire around a first length of wire to form a twisted wire joint comprising:
 providing an apparatus as claimed in  claim 1 ;   extending a first length of wire through the aperture of the rotatable member;   positioning a second length of wire across and adjacent to the second length of wire; and   rotating the rotatable member such that the engagement surface engages with the second length of wire and twists the second length of wire around the first length of wire to form a twisted wire joint at least substantially within the recess of the rotatable member and which includes a plurality of full turns of the second length of wire around the first length of wire.   
   
   
       24 . A method as claimed in  claim 23 , comprising, prior to rotating the rotatable member, bending a free end of the second length of wire so that it is engaged by the engagement surface upon rotation of the rotatable member.