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3.3. The contrivance for untwisting of thread

The “moulinet” is twisted of 6 or 12 cotton threads. More thin threads are needed for lace making. They can be made by splitting (untwisting) the “moulinet”.

Manual untwisting does not prove to be simple as it seems at first sight. It becomes just clear that an operator ought to have the third and fourth hands. In other words this work can not be done without an assistant.

Splitting technique consists of three operations:

- pull out of the clew a part of “mouline”, untwist it and split at three flows of two-, three- or four-fold thread;

- rewind split threads around three intermediate spools keeping equal tension;

- stop splitting every time when the next part of “moulinet” is being pull out of the clew.

It ought to keep strictly the rule - avoid excessive touching the thread by fingers to save its cleanness.

The problem of keeping thread tension constant arises because of growing difference in length of untwisted threads. The greater is difference, the less is tension. The state of emergency takes place. One must stop splitting and eliminate thread sag in the emergence channel by means of additional rotation of the spool. Of course it is impossible in this case to avoid needless touching the thread.

Authors of the book suggest method of splitting that provides automatic compensation of thread sag using gravity strength. The principle can be seen on the cinematic scheme (Fig.3.5).

Fig.3.5. Compensation of thread sag

Mass of the clew 1 is enlarged up to 150 grams (0.33 pound) with a metallic ball inserted into it. The clew works as a plumb. It hangs at pulled out thread (L » 1.5 meter or L » 5 foots) and rotates untwisting the “moulinet”.

The comb 2 splits the “moulinet” at three threads. The split thread moves towards the comb 3 going under the roller 4 that is pulled down with gravity strength F₁.

The split thread moves farther above roller 5 and under roller 6, both being set on the disk 7. The gravity strength F₂ turns the disk 7 clockwise.

It is to be noticed that using two different compensators 4 and 7 is not obligatory. The matter is both realize the same principle. On this reason it would be possible to change the disk compensator 7 with falling roller like the roller 4. However author saved both compensators as they are to demonstrate possible variants of tension controlling.

After the roller 6 the split thread goes through a guiding comb 8 to the intermediate spool 9 set on the main roller which is rotated by hand of an operator i.e. a lace maker.

If tensions of three threads are equal, the balance of all strengths (gravity and friction) takes place. The roller 4 moves up to level of the combs 2 and 3; centers of the rollers 6 and 7 are at the horizontal line.

As soon as one of three threads becomes longer then other two, thread tension relaxes and the balance of strengths comes at other position of rollers. The roller 4 falls and the disk 7 turns clockwise. Movement of rollers stops when tension restores at this channel and becomes equal tension in other channels.

When the current piece of the “moulinet” is split, it is necessary to stop movement of disks 7 and spools 9. The pause is needed to pull the next “moulinet” piece out of the clew 1 and to untwist it.

There are many methods to work out a cinematic scheme according to the compensation principle. One of methods is presented on Fig.3.6 (front view) and Fig.3.7 (plan view).

Fig.3.6. The contrivance for untwisting of “moulinet”. Plan view

Fig.3.7. The contrivance for untwisting of “moulinet”. Side view

All basic units are seen on Fig.3.6 including:
- the main shaft with three spools and the fly-wheel;
- the reducer (on the left from the shaft);
- the eccentric mechanism and three guiding forks;
- three disk compensators and the brake lath in front of the disks;
- the frame and two combs on it;
- three lever compensators that can be seen through the frame;
- the box intended to save the clew; besides the clew there are three spools saving the split thread.
Fig.3.7 shows the following units:
- the brake of the fly-wheel;
- the lever compensators under the combs;
- the levers tied to the disk compensators with the cords