Disposable handcuffs

1. Disposable handcuffs comprising:

a flat strap of flexible material including a central section, two outer sections and two loop sections between said outer sections and said central section;

a box for locking the flat strap therein having a first side, a second side and a pair of passages for receiving the flat strap for longitudinal motion within the passages, the ends of the outer sections extending from the passages on the first side of the box and the loop sections extending from the passages on the second side of the box;

a fixing element able to fix the central section on the box;

each of the passages having a strap supporting wall and an opposite partially offset wall forming a cavity between said walls open to the first side of the box;

a rotational body located within each of the cavities for contact of the rotational surface thereof with the offset wall on one side and the flat strap on the other side;

a boss including a sharp end formed as a tip extending from the rotational surface to engage the flat strap in the area adjacent to the first side of the box and to protrude inside the flat strap to a position where the tip leans against the strap supporting wall; and

a cover fixed on the first side of the box and overlapping the cavities.

2. The disposable handcuffs of claim l, wherein a holding down member is disposed between the rotational body and the cover to keep the sharp end of the boss in contact with the flat strap.

3. The disposable handcuffs of claim 2 , wherein the holding down member is a roller made of elastic material.

4. The disposable handcuffs of claim 1 , wherein each cavity narrows from the first side of the box in that the offset wall is inclined at an angle of 2 to 5 degrees.

5. The disposable handcuffs of claim 1 , wherein the box has two central passages in its central part between the passages for fixing the central section of the flat strap in the box.

6. The disposable handcuffs of claim 5 , wherein the box has a recess in the central part of the first side for fixedly mounting the cover on the box to secure the central section of the flat strap to the box.

7. The disposable handcuffs of claim 5 , wherein the cover has a central edge and two lateral ledges and the first side of the box has complementary surfaces to crimp the flat strap between the central edge and the lateral ledges of the cover and the first side of the box.

8. The disposable handcuffs of claim 1 , wherein the flat strap is made of a textile material.

9. Disposable handcuffs comprising:

a flat strap of flexible material including two outer sections, a central section and two loop sections between said outer sections and said central section;

a box having a first side and a second side and a pair of passages each for receiving outer sections of the strap for longitudinal motion within the passages, the ends of the outer sections extending from the first side of the box and the loop sections extending from the second side of the box;

each of the passages having a strap supporting wall and an opposite partially offset wall forming a cavity between said walls open to the first side of the box and narrowing from the first side of the box by inclining the offset wall;

a cover fixed on the first side of the box and overlapping the cavities;

a rotational body located within each of the cavities for contact of the rotational surface thereof with the offset wall on one side and with the flat strap on the other side;

a boss including a sharp end formed as a tip extending from the rotational surface to engage the flat strap in the area adjacent to the first side of the box and to protrude inside the flat strap to a position where the tip leans against the strap supporting wall; and

a holding down member located between the rotational body and the cover to keep the sharp end of the boss in contact with the flat strap.