Patent Publication Number: US-2006010923-A1

Title: Method of half-gauge knitting and article thus obtained

Description:
This invention relates to a method for half-gauge knitting and the article thus obtained.  
      It is known that on knitting looms with weft stitches (in other words working at a gauge smaller than the nominal gauge), a loom can be “half-gauged” particularly to reduce material consumption and knitting time, or to use thicker thread.  
      The most frequently used method for circular knitting looms is to change the machine cylinder. For example, this is what is done by the Santoni manufacturer for its 15″ (38.1 cm) machines with 1056 0.5 mm thick needles for gauge 22, becoming 1104 0.41 mm thick needles for gauge 24, 1248 0.41 mm thick needles for gauge 26, 1344 0.41 mm thick needles for gauge 28, and 1488 0.34 mm thick needles for gauge 32. This method is very expensive because the cylinder, ring, sinker and saw assemblies have to be available in stock; and furthermore, three days of work are necessary for two technicians to make the change.  
      The other conventional method is to remove or not select one out of every two needles. For example, a 15″ Santoni SM8 loom with 1344 0.41 mm thick needles for gauge 28 can be modified to knit with half of the needles, namely 672 needles. This method is very fast, there are no costs involved and it can save material consumption and machine cycle time to make an equivalent article; but the knit produced has a low quality appearance. This lower quality aspect is caused by large differences between stitch and inter-stitch dimensions.  
      The purpose of this invention is half-gauge knitting of an article with satisfactory quality, in other words with the appearance of a balanced knit.  
      The invention achieves its purpose through the use of a method for half-gauge knitting of a textile article using a weft stitches loom comprising needles separated by sinkers, of the type in which the article is knitted using one out of every two needles, characterised in that one sinker out of two has been withdrawn from the loom.  
      The fact or removing one sinker out of two enables the thread to slide better as the stitch is formed to obtain equivalent stitch and inter-stitch dimensions.  
      The invention is applicable to all looms working in weft stitches, but is particularly useful with a circular loom.  
      The invention also relates to the article obtained using the method according to the invention. Particularly on a circular loom, the article obtained can be used for manufacturing seamless articles designed to clothe the trunk (undervests, midriff tops, bras, etc.) or to wear on the legs (stockings, tights, socks, etc.).  
    
    
      Other characteristics and advantages of the invention will become clear from the following description of example embodiments. It refers to the attached drawings on which:  
       FIG. 1  is a diagrammatic view of stitches being formed on a traditional loom in normal knitting.  
       FIG. 2  shows a corresponding diagrammatic view of stitches being formed on the same loom in conventional half-gauge knitting.  
       FIG. 3  shows a corresponding diagrammatic view of stitches being formed on the same transformed loom in half-gauge knitting according to the invention.  
       FIG. 4  shows a view of the stitches of a conventional half-gauge knit.  
       FIG. 5  shows a view of the stitches of a half-gauge knit according to the invention. 
    
    
      FIGS.  1  to  3  show a part of a weft stitches knitting loom that could be straight (as shown on the drawing for reasons of simplicity) or circular. Conventionally, it comprises needles  1  with their hook  2  that will collect the thread and their mobile arm  3 . In this case, the needles are vertical and separated by sinkers  4 .  
      In  FIG. 1  that represents normal knitting, all the needles  1  of the loom work in the A, B, C, D, E positions with their associated sinker  4   a ,  4   b ,  4   c ,  4   d ,  4   e , and therefore form thread stitches  6   a ,  6   b ,  6   c ,  6   d  and  6   e . The appearance of the knit obtained is normal, and the stitches are balanced (in this case a jersey knit).  
      In  FIG. 2 , that shows conventional half-gauging knitting with one needle out of two on the same loom as in  FIG. 1 , only the needles in positions A, C, E are working, to form stitches  6   a ,  6   c ,  6   e  that are approximately the same shape as shown in  FIG. 1 . But due to the presence of two sinkers between two working needles (for example sinkers  4   b  and  4   c  between needles in positions A and C), a large inter-stitch  5  distance is formed between these two sinkers that is quite obvious in the knit between two columns of stitches  6  (see  FIG. 4 ).  
      In  FIG. 3  that represents knitting according to the invention, the loom in  FIGS. 1 and 2  has been transformed by eliminating one out of two sinkers (sinkers  4   b  and  4   d  corresponding to needles  1  in positions B and D that are not working), such that all that remains are sinkers  4   a ,  4   c  and  4   e . Consequently, during formation of stitches  6  by the needles  1 , the stitches are not hindered by an excessively close sinker and can become wider such that the inter-stitch distance  5  and the stitch size  6  are comparable and are balanced as shown by the appearance of the knit obtained (see  FIG. 5 ).  
      We will now describe a specific example embodiment.  
      A Santoni SM8 15″ circular loom is originally equipped with 1344 0.41 mm thick gauge 28 needles for knitting with all needles. Tubes were knitted with a two-ended polyamide 66 thread, 110 dtex 34 textured strands, on all knitting feeds, on an 82 cm wide prefixed (for example stabilized by steam) extension base measured at 4.3 kg. Consequently, the length of thread absorbed at a tension of 5 g is 4.50 m per cylinder turn. The tubes thus knitted based on 800 rows are used to define the original parameters: the regular appearance of the knit, thread consumption, knitting time, the absorbed thread length per turn, the width of the tube when flat, its volume at a force of 6 kg and weight per m 2 . These parameters are given in the corresponding column in table I attached.  
      Without changing the mechanical settings of the machine, half-gauge tubes were knitted using one needle out of two, therefore using 672 needles, and table I contains the corresponding parameters.  
      Finally, the machine was modified by removing one sinker out of two, and the circular spring surrounding the ring of sinkers and used to push them towards the centre of the needles cylinder was changed to compensate for the absence of one sinker out of two, providing a slightly smaller spring than is normally used, for example using a 14″ (35.5 cm) machine spring for a 15″ (38.1 cm) machine, for which one sinker out of two has been removed. The parameters are also shown in Table I.  
      The comparison of the three knitting modes given in table I shows that the width of the fixed flat tube for the knit according to the invention is narrower than for the other two modes, and the weight per m 2  is intermediate between their weights. This confirms that the knit is better balanced than a knit obtained by simply reducing the number of needles, as shown by the visual appearance of the knit obtained.  
      In the same way as for a conventional half-gauge article, the fact of knitting according to the invention reduces the thickness of the knit, but this can be compensated by increasing the thickness of the thread used in the ratio of the measured weight per m 2 .  
      For example, preparation of the transformed loom according to the invention requires about 8 hours work for a technician; therefore it is considerably faster than the method consisting of completely changing the machine cylinder.  
                                   TABLE I                                       Knit with                   Knit with       half-gauge loom   Knitting               original       using one needle   according       Based on       equipment       out of 2, namely   to the       800 rows       1344 needles       672 needles   invention                                                            thread   90.63   g   59.75   g   55.29   g       consumption       knitting time   2   min   2   min   2   min           21   s   21   s   21   s       thread length   4.50   m/t   2.65   m/t   2.57   m/t       absorbed per       cylinder turn       flat prefixed   49.5   cm   33   cm   30   cm       tube width       flat prefixed   43.5   cm   45   cm   42   cm       tube height       prefixed tube   82   cm   63   cm   58   cm       extension       prefixed tube   62   cm   84   cm   75   cm       volume       weight per   176   g   152   g   165   g       m2 of knit                             for a same   lower thread   36%   37%       height of   consumption       flat prefixed   shorter    4%    3%       tube   knitting time       For a same   lower thread   51%   50%       prefixed tube   consumption       volume   shorter   26%   17%           knitting time