Flat bed machines have four different classes; (i) V-bed flat machines which have two inverted V-formed needle beds; (ii) Purl machines which have double ended needles; (iii) machines that have a single bed of needles which include most domestic models and a few hand manipulated intarsia machines ; and (iv) Cotton patent machines which are single-bed machines with bearded needles arranged vertically . Bearded needles are the needles having an extended terminal hook or beard that can be flexed to close the hook .
1.2. Historical Events Contributing to the Development of Seamless Knitting
In the evolution of seamless knitting it is important to review the developments in knitting that directly affect three dimensional knitting techniques. Kadolph and Langford  explain that historical remnants of knit fabrics have been dated from A.D. 250 in the Palestine area. Knitting was accomplished by a hand process until 1589, when William Lee in England invented a flat-bed weft knitting frame to create hosiery . The first operational V-bed flat knitting machine using latch needles was invented in 1863 by Issac W. Lamb . William Cotton of Loughborough took out a patent in 1864 for his rotary-driven machine that used a flat bed to produce fully-fashioned garments . According to Hunter , in the 1800�s, the flat knitting machine was fitted with sinkers which controlled loops in order to knit single jersey tubular articles such as gloves, socks and berets. In 1940, the manufacture of shaped knitted skirts was patented in the USA. This permitted darting on knitted skirts using a technique called "flechage" (See glossary). The flechage technique not only improved drape and fit, but cut production cost. In 1955, the Hosiery Trade Journal reported on the automatic knitting of traditional berets through the shaping of components. In the 1960�s, the Shima Seiki company further explored the tubular-type knitting principle commercially to produce gloves. Also, in the mid1960's, engineers at Courtaulds in the UK established British patents on the idea of producing garments by joining tube knitting. However, the method was too advanced to be commercialized at that time. By 1995, Shima Seiki fully developed shaped seamless knitting . Recently, by employing more advanced computerized systems, simpler programming was possible, and the computerized systems enabled the production of more complicated and sophisticated knitted structures and products. Table 1 introduces the historical events of seamless knitting.