Device for embedding threads in a rubber profiled element comprising a blunt-tipped rotary needle

1. Device for embedding an insert into a rubber profiled element in a given direction, comprising:

at least one feeder for feeding a thread continuously,

a moving support capable of moving on a structure in a rectilinear reciprocating movement between a raised position and a lowered position, said moving support comprising a base,

at least one hollow needle comprising a channel of longitudinal axis XX′ inside which the thread is able to run, which needle is fixed by one of its ends to the base of the moving support and comprising at its other end a tip capable of penetrating said rubber profiled element,

a cutting means arranged on the support, comprising a blade capable of cutting off the thread leaving the tip of the needle on each cycle of the reciprocating movement of the needle, when said tip is in a raised position so as to release a given length of thread constituting a tail at the outlet of the needle,

wherein the moving support comprises means capable of rotating the needle about its longitudinal axis XX′, and wherein the tip of said needle is blunt, such that when cutting any radial profile of said tip into segments of 0.01 mm in length, the tangent at any point of a given segment (Sk) forms an angle of less than 20° with the tangent at any other point of said segment (Sk) and at any segments (S k−1 , S k+1 ) being adjacent to said segment (S k ), the tangent at any point of said segment (S k ) forms an angle of less than 20° with the tangent at any point of the segments (S k−1 , S k+1 ).

2. Device according to claim 1 , wherein the tip comprises a line forming the edge (A) of said tip, said line is arranged substantially in a plane perpendicular to the axis (XX′) of the needle.

3. Device according to claim 1 , wherein the means for rotating the needle are capable of rotating said needle at a speed of between 5000 revolutions/min and 50 000 revolutions/min and usually between 10 000 rev/min and 35 000 rev/min.

4. Device according to claim 1 , wherein the outside diameter of the needle is between 0.7 mm and 3 mm.

5. Device according to claim 1 , wherein the cutting means is a knife with a reciprocating movement moving in a plane.

6. Device according to claim 1 , wherein the cutting means is disengageable.

7. Device according to claim 1 , in which the needle is combined with an immobilizer for immobilizing the thread that is arranged on the moving support and capable of preventing the thread from running in the needle in a direction opposite to the feed direction.

8. Device according to claim 1 , in which the channel of the needle comprises an inlet, the feeder is connected to a controller capable of maintaining the thread portion situated between said feeder and at a zero tension whatever the position of the moving support.

9. Device according to claim 1 , wherein the direction (XX′) of the needle is inclined with respect to the structure.

10. Device for embedding a thread or a plurality of threads into a rubber profiled element in a given direction, comprising

a moving support capable of moving on a structure in a rectilinear reciprocating movement between a raised position and a lowered position, said moving support comprising a base,

a plurality of hollow needles comprising a channel of longitudinal axis XX′ inside which a thread is able to run, which needles are each fixed by one of their ends to the base of the moving support and comprising at the other end a tip capable of penetrating said rubber profiled element,

a plurality of feeders for feeding thread capable of feeding each needle continuously,

a cutting means arranged on the structure, comprising a blade capable of cutting off the threads leaving the tip of each of the needles on each cycle of the reciprocating movement, so as to release a given length of thread constituting a tail at the outlet of each of the needles,

wherein the moving support comprises means capable of rotating each of the needles about its longitudinal axis XX′, and in that the tip of each of the needles is blunt such that, when cutting any radial profile of said tip into segments of 0.01 mm in length, a given segment (S k ) having two adjacent segments (S k−1 , S k+1 ), the tangent at any point of a given segment (Sk) forms an angle of less than 20° with the tangent at any point of the adjacent segments (Sk−1, Sk+1).

11. Method of embedding an insert formed by a thread portion into a rubber profiled element via one of its surfaces, using a device according to claim 1 , comprising one or more needles, in which each of the needles describes the steps during which:

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

B—lowering the tip of the needle so as to cause the tip of said needle to penetrate the profiled element to a given depth which is greater than the length of the tail,

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

E—cutting the thread off at the surface of the profiled element using a cutting means so as to release a new tail of given length,

wherein the needle is rotated about its longitudinal axis.

12. Method according to claim 11 , in which the needle is rotated at a speed of between 5000 revolutions/min and 50 000 revolutions/min.

13. Method according to claim 11 , in which, following step E:

F—moving the profiled element by a given pitch with respect to the structure so as to embed another insert.

14. Method according to claim 13 , wherein the cutting means is neutralized so as to eliminate step E, and wherein the tip of the needle is raised above the surface of the rubber profiled element by a height substantially equal to the depth, increased by the length of the pitch, so as to form a new tail.