III Read and translate the following text

The Three Main Types of Needles

The needle is the basic element of loop formation.

There are three most commonly used types of needle: the latch needle (a), the spring-beard needle (b) and the compound needle (c).

We can divide a needle into three main parts:

A. the hook, which takes and retains the thread to be looped;

B. the hook opening and closing device, that allows the hook to alternatively take a new thread and release the previous one;

C. a system allowing the needle to move and form the loop.

During the loop formation the hook must be closed to transfer the previous stitch already formed on the new thread; this operation takes place in different ways according to the type of needle used.

With the latch needle, the latch is hinged at a certain distance from the hook and can revolve:

- the anticlockwise rotation, produced by the pressure of the loop, which is originally inside the hook, opens the hook to allow a new thread to be fed;

- the clockwise rotation, produced by the pressure of the loop on the stem, allows the hook to be closed and subsequently knocked over on the new thread.

In spring-beard needles, the hook is closed by an external device, the presser, which, at a specific time during the stitch formation, comes in contact with it and makes it bend and close. When the presser is pulled away, the hook springs back and opens the needle automatically.

The compound needle includes (inside the internal groove of the stem) a sliding closing element, which opens and closes the hook through its upward and downward motion.

The use of the latch needle for knitting machinery has become increasingly widespread over the last 50 years; the main advantage of this needle is that has a reduced stroke, which means a higher speed and increased production capacity without stressing the thread during the transfer steps. In addition, it offers a wider sampling potential and a better quality of the fabric manufactured. The main drawbacks include higher costs and a more complicated operating technology.

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