Device and method for embedding threads in a rubber profiled element

1. A device for embedding a thread in a rubber profiled element in a given direction comprising:

a continuous thread-feed means arranged on a fixed structure;

a moving support able to run along a structure in a reciprocating rectilinear movement between a raised position and a lowered position and comprising a top and a base between which is formed a duct intended to guide the thread;

a hollow needle comprising a canal in which the said thread is able to run, which needle is fixed by one of its ends to the base of the moving support in the continuation of the duct, and comprising at its other end a tip capable of penetrating the said rubber profiled element; and

a cutting means arranged on the structure, comprising a rotary blade comprising a cutting portion able, when the needle is in the raised position, to cut off the thread at a given distance from the tip of the needle upon each cycle of reciprocating movement of the needle and to produce a tail of thread extending from the tip of the needle,

wherein the cutting means comprises a paddle arranged behind the cutting portion of the blade and intended to fold the tail around the tip of the needle just after the thread has been cut by the blade.

2. The device according to claim 1 , wherein the cutting means is a cutter that rotates about an axis parallel to the direction of movement of the needle.

3. The device according to claim 1 , wherein the feed means is connected to a regulating means configured to keep the portion of thread situated between the said feed means and the entrance to the duct of the moving support at zero tension irrespective of the position of the moving support.

4. A method for embedding an insert formed of a length of thread in a rubber profiled element via one of the surfaces thereof, using a device according to claim 1 , comprising:

A—releasing a given length of thread on the tip side to constitute a tail when the needle is in the raised position above the surface of the profiled element,

B—lowering the tip of the needle to make the tip of the needle penetrate the profiled element over a given depth,

C—extracting the needle from the profiled element while allowing the thread to run along inside the needle,

D—raising the tip of the needle by a given height, above the surface of the profiled element, so as to release a length of thread between the tip of the needle and the surface of the profiled element which length is less than the depth to which the needle penetrated the profiled element, and

E—cutting off the thread level with the surface of the profiled element using a cutting means the rotary blade of which comprises a paddle positioned to the rear of the cutting portion of the said blade, so as to release a new tail of given length,

wherein, just after cutting, the said paddle imparts to the tail an impulse in a direction substantially perpendicular to the direction of travel of the needle so as to fold the tail around the tip of the needle.

5. The method according to claim 4 , wherein, on completion of step F, the method further comprising moving the profiled element by a given step length with respect to the structure so that a new insert can be embedded.

6. The method according to claim 4 , wherein, during step E, the thread is cut off substantially level with the surface of the profiled element.

7. The method according to claim 4 , wherein the distance between the top of the paddle and the tip of the needle, when the needle is in the raised position, is adjusted so that this distance is between one and five times the diameter of the thread.

8. The method according to claim 4 , wherein the feed means is regulated in such a way that the portion of thread between the feed means and the entry to the duct of the needle forms a loop B irrespective of the position of the moving support.