Plastic bobbin and a method of manufacturing such a bobbin

Abstract

A method of manufacturing a bobbin of plastic that includes injection moulding a U-shaped channel including a base and two side walls, bending the U-shaped channel until ends of the U-shaped channel abut each other, and connecting the ends with each other in a position so a bottom surface of the base forms an inner circumference of a cylinder. The base includes a plurality of cylinder elements and each side wall forms a circumferential end flange. Each end flange includes a plurality of spaced-apart, radial flange elements.

1 - 12 . (canceled)  
   
   
       13 . A method of manufacturing a bobbin of plastic comprising: 
 injection moulding a U-shaped channel including a base and two side walls;    bending the U-shaped channel until ends of the U-shaped channel abut each other; wherein the base includes a plurality of cylinder elements and each side wall forms a circumferential end flange, each end flange includes a plurality of spaced-apart, radial flange elements;    connecting said ends with each other in a position so a bottom surface of the base forms an inner circumference of a cylinder.    
   
   
       14 . A method as claimed in  claim 13 , wherein the injection moulding includes injection moulding the U-shaped channel in one piece.  
   
   
       15 . A method as claimed in  claim 13 , wherein the injection moulding a U-shaped channel includes providing an axial inner groove in the cylinder between each adjacent cylinder elements.  
   
   
       16 . A method as claimed in  claim 13 , wherein the injection moulding a U-shaped channel includes providing an axial outer groove in the cylinder between each adjacent cylinder element.  
   
   
       17 . A method as claimed in  claim 13 , wherein the bending includes bending the U-shaped channel until sides of the axial inner grooves in the cylinder abut each other.  
   
   
       18 . A method as claimed in  claim 13 , wherein the connecting includes inserting between two L-shaped holder segments, formed on a cylinder element at a first end of the U-shaped channel, a projection at a second end of the U-shaped channel until a stop lug formed on the cylinder element at the first end between the two holder segments is inserted in a hole in the projection.  
   
   
       19 . A method as claimed in  claim 13 , wherein the injection moulding a U-shaped channel includes providing at an end of each flange element connected with a cylinder element of the U-shaped channel a lug which extends past the cylinder element and has an extent decreasing in a longitudinal direction of the U-shaped channel away from the cylinder element; and 
 the bending the U-shaped channel to form a cylinder includes bending the U-shaped channel until each lug is brought into abutment against a neighbouring lug.    
   
   
       20 . A bobbin of plastic comprising: 
 an injection moulded U-shaped channel, comprising a base and two side walls;    wherein the base includes a plurality of cylinder elements, each being connected to at least one adjacent cylinder element by plastic thinner than the at least one adjacent cylinder element;    wherein each side wall comprises an end flange, each end flange having a plurality of flange elements; and    wherein a first end of the U-shaped channel is provided with a first connecting element and the second end of the U-shaped channel is provided with a second connecting element, mating with the first connecting element.    
   
   
       21 . A bobbin as claimed in  claim 20 , in which the cylinder has a plurality of axial inner grooves between adjacent flange elements.  
   
   
       22 . A bobbin as claimed in  claim 21 , in which the plurality of inner grooves are wedge-shaped in cross-section  
   
   
       23 . A bobbin as claimed in  claim 20 , in which the cylinder has a plurality of axial outer grooves provided between adjacent cylinder elements.  
   
   
       24 . A bobbin as claimed in  claim 20 , in which each flange element has a lug at a radially inner end, the lug is shaped to abut an adjacent lug when the U-shaped channel is bent to form the cylinder.