Sewing apparatus and method

Abstract

A tubular fabric article is gripped at either end on gripping rings ( 24 ) which can be rotated and moved axially with respect to a fixed position D-D. A fixed needle mechanism ( 30 ) extends within the tubular article. A needle ( 36 ) is oscillated between a retracted and extended position and cooperates with a hook and bobbin mechanism to form stitches.

1 . Apparatus for sewing tubular articles, comprising: 
 holding means for holding the article at both ends;    a needle assembly positioned, in use, within the article, the needle assembly comprising a needle having a needle point and an eye adjacent to the needle point, the needle drive means for cyclically driving the needle between a retracted position and an extended position;    needle thread supply means for supplying a needle thread from a reservoir to the eye of the needle;    a stitch-forming mechanism located in a position which is fixed in relation to the needle assembly and which, in use, is outside the tubular article, the stitch-forming mechanism being adapted to form a stitch using a loop formed in the needle thread; and    motion means for producing relative axial and rotational motion between the holding means and the needle assembly.    
   
   
       2 . Apparatus according to clam  1 , in which the needle assembly and the stitch-forming mechanism are stationary in position and the holding means is moved axially and rotationally, with respect to them.  
   
   
       3 . Apparatus according to  claim 2 , in which the axial and rotational motion of the holding means is produced by means of servo motors or stepping motors.  
   
   
       4 . Apparatus according to  claim 1 , in which the stitch-forming mechanism comprises a hook and bobbin or a shuttle for passing a second thread through the needle thread loop to form a lock stitch.  
   
   
       5 . Apparatus according to  claim 1 , in which the needle assembly comprises a tubular support containing the needle and the needle drive means and through which is fed the needle thread.  
   
   
       6 . Apparatus according to  claim 5 , in which the needle is of arcuate form and is pivoted to the tubular support.  
   
   
       7 . Apparatus according to  claim 6 , in which the needle drive means comprises a push rod driving the needle through a pivoted link.  
   
   
       8 . Apparatus according to  claim 7 , in which the pivot points and the stroke of the push rod are so arranged that the needle oscillates through an angle greater than 90°.  
   
   
       9 . Apparatus according to  claim 8 , in which the needle oscillates through an angle of about 1350.  
   
   
       10 . A needle for use in the apparatus of  claim 6 , comprising a needle blade formed as an arc of a circle, a first end of the needle blade being formed as a needle point and the needle blade having an eye adjacent the needle point; and a second end of the needle blade being secured to or formed integrally with a needle shank, the needle shank being adapted to receive a pivotal mounting pin at a location within said circle.  
   
   
       11 . A needle according to  claim 10 , in which a thread groove is formed in the surface of the needle blade on the outside of the arc.  
   
   
       12 . A needle according to  claim 11 , in which said thread groove extends from the eye to said second end of the needle blade.  
   
   
       13 . (canceled)  
   
   
       14 . Apparatus according to  claim 1 , including a wire guide arranged to feed a reinforcement wire to the exterior of the tubular article adjacent the needle position.  
   
   
       15 . Apparatus according to  claim 14 , in which the wire guide is movable between two positions on either side of the needle position.  
   
   
       16 . A method of sewing a tubular article comprising the steps of: 
 (a) passing a needle carrying a needle thread from the interior of the article to the exterior;    (b) forming a loop in the needle thread exteriorly of the article;    (c) using the needle thread loop to form a stitch;    (d) retracting the needle into the interior of the article;    (e) taking up the needle thread to close said loop;    (f) moving the article axially and/or rotationally with respect to the needle location; and    (g) repeating steps (a) to (f).    
   
   
       17 . The method of  claim 16 , in which the stitch is a lock stitch formed by passing a second thread through the loop of the needle thread.