Construction and Operating Principles of a Ricot Warp Knitting Machine

What are the construction and principles of tricot warp knitting machines? These machines have a wide adaptability to raw materials and fabric types and have a high machine productivity, hence fast development.

Construction of tricot warp knitting machines

Using one or several parallel sets of yarn feeding into all working needles in the warp direction, a loop knit fabric is formed, a process called warp knitting which results in warp knitted fabrics. The machines that complete this process are called tricot warp knitting machines. The main circular components of tricot warp knitting machines are knitting needles, guiding needles, sinkers, and pressers. Knitting needles are arranged on the needle bed and move together with it; guiding needles are mounted on the comb, and the warp yarns pass through the holes to form loops on the needles which knit together with sinkers and other circular components to form the fabric.

Working Principles of tricot warp knitting machines

The tricot warp knitting machines mainly consist of knitting mechanism, comb transverse mechanism, warp feeding mechanism, traction winding mechanism, and transmission mechanism. Their working principles are as follows:

• The knitting mechanism includes needle bed, comb, sinker bed, and presser. It is generally driven by cams or eccentric connecting rods. Cams are commonly used in tricot warp knitting machines with low speeds and complicated circular component movement. Eccentric connecting rods are easier to process, run at high speeds with minimal wear and noise, and are widely used in high-speed tricot warp knitting machines;

• The comb transverse mechanism moves the comb to move horizontally according to the requirements of the fabric structure, which helps to knit warp yarn onto needles to form a knitted fabric with a certain organizational structure, typically in the form of a flower or cam;
  

• The warp feeding mechanism feeds the warp yarn into the knitting area. There are usually two types: passive and active. Passive mechanism feeds the warp yarn by pulling it with tension without the need for a specialized warp shaft drive device, which is suitable for low-speed tricot warp knitting machines with more complex feeding rules. Active feeding mechanism uses a specialized drive device to rotate the warp shaft to feed the warp yarn, and it can be divided into tension sensing type and line speed sensing type;
  

• The traction winding mechanism pulls the fabric out of the knitting area at a predetermined speed and rolls it up into fabric roll.
  

Classification of tricot warp knitting machines

According to the direction of the fabric leading-out, tricot warp knitting machines can be divided into two types

Tricot warp knitting machines (also known as high-speed tricot warp knitting machines) and Raschel tricot warp knitting machines (also known as patterned tricot warp knitting machines). Originally, the difference between the two types of tricot warp knitting machines was that the former was a fine hook knitting machine with high speed and relatively single products, and the latter was a rough tongue needle knitting machine with low speed and more varied patterned products.

Nowadays, both types of tricot warp knitting machines use the most advanced composite needles: groove needles, and both machines have high speed. The type of warp knitting machine can be determined by the angle between the fabric and the knitting needle when they are separated. Specifically, the angle is close to 90° on Tricot machines, and close to 180° on Raschel machines, which is nearly vertical. Some fabrics are only suitable for Raschel machines, such as spandex mesh fabrics, while others are more suitable for Tricot machines, such as bi-directional elastic plain fabrics;

According to the needle density, tricot warp knitting machines can be divided into two types

Single needle bed tricot warp knitting machines and double needle bed tricot warp knitting machines.