The card cylinder and cards are practically the same as used on the purl stitch machine and explained in a former chapter, but obviously the application must be somewhat different owing to the different construction and manner of operating the needles in this machine. Inasmuch as there are two sets of needles opposed one to the other, and each set forms the stitches which show on their respective sides of the fabric, it is possible and customary to make the designs in solid colors, differing in this respect from the links and links or purl stitch machine.
Fig. 83.
Dubied Automatic Jacquard Flat Bed Machine.
Fig. 84.
Back of Flat Jacquard Machine Showing a Set of Cards, Mounted.
The jacquard designed fabrics are usually made in what would, on an ordinary machine, be the one and one rib or plain stitch. The tuck or cardigan stitch is not resorted to to bring out the design as in some other systems. Strictly speaking, however, the stitch is not what could properly be called a rib stitch, but is a combination of a plain rib and jersey stitch when made on the single jacquard, and is almost wholly of the jersey stitch construction when made on the double jacquard where the design is brought out on both sides of the fabric. The single jacquard is so called when the jacquard arrangement is on one plate only, usually the back one. The double jacquard machine is one which has the jacquard attachment on both the front and back plates. With the single jacquard the design can be brought out on one side of the fabric only, while with the double jacquard the design may be brought out on both sides of the fabric, but the colors would be reversed.
Type of Fabric Produced
Before going into the mechanical construction of the attachment we will to some extent analyze the fabric to find out what must be done to produce it. Referring to Fig. 87, which is a photographic reproduction of a fabric made on the machine under discussion, it will be noted that both the design and the ground are in solid colors. The rectangular figures which might be called the design are in solid black, while the squares, both the large ones and the small ones, which would be the ground, are solid white. It should be understood that there are two yarn carriers used in making this fabric, one for the white yarn and one for the black, and that these carriers are changed every round; that is, one round of white, and one round of black, alternating throughout the fabric.
Now inasmuch as we know that the fabric is made in the plain stitch, it is quite obvious that in order to make this design means must be provided to permit only those needles to knit which are making the white ground on any course in which the carrier with the white yarn is being used. Similarly only those needles making the black design must be permitted to knit on the course in which the carrier with the black yarn is used. The needles or wales, of course, run vertically in the fabric, while the rectangular design is diagonal, therefore it is plain that the number of needles or their relative positions must be changed each course.
In this fabric the design is brought out on one side only, the back plate, and the needles on the opposite side or front plate are knitting each time the carriage is moved across the machine as explained in detail later. This may be plainly seen in Fig. 87, where the corner is turned over to show the back of the fabric.