FR2731895A1 - Self-sealing trocar with automatic closure - Google Patents

Abstract

The trocar, consists of a main introduction tube (1) and a guide tube (7) attached to it. It has an elastic membrane (5) and a shutter in the guide tube, both of which open under the pressure of a tube fed through the guide tube and into the introduction tube, and close automatically when it is withdrawn. The membrane (5) forms part of a ring (4) fitting onto the end of the introduction tube. It is conical in shape, is slit to form two identical sealing lips, and is made from an elastomer material such as silicone. The shutter is in the form of a plate hinged at one end to the guide tube's inner surface.

Description

SELF-LOCKING TROCART WITH AUTOMATIC CLOSING
The present invention relates to a method for automatically closing a self-locking trocar, in particular applicable to laparoscopy, as well as a device implementing it. Laparoscopy is a method of exploring the peritoneal cavity, which consists, under general or local anesthesia, of piercing the abdominal wall, in the vicinity of the region to be examined, using a perforating instrument threaded through the inside of a trocar. Once the perforation has been made, the instrument is withdrawn and a sterile gas is inserted through the trocar which remains in place inside the peritoneum, thus creating a pneumoperitoneum. The artificially created gas pocket thus allows the practitioner to intervene on the organs located inside, without being hampered by the peritoneum. To this end, the instruments necessary for the intervention are introduced inside the trocar. a light optical system, elongated laparoscopic forceps, etc. Document FR 2 689 384 is already known in the name of the applicant, which reveals a type of trocar allowing the interventions described above to be carried out. In this type of trocar, the vacuum sealing and the longitudinal maintenance of the instrument are carried out using a lip membrane. The seal during handling, that is to say when an instrument is introduced into the trocar, through the lips of said membrane, is itself provided by an O-ring located at the proximal end of said trocar. The pressure exerted by the lips of the membrane on the instrument introduced into the trocar is relatively firm, which is why said instrument passes through a coaxial tube mounted to slide inside the trocar. The sliding of this inner tube has the effect of opening the lips of the membrane and keeping them open. In this position, the instrument can slide freely inside the trocar, which makes it possible to carry out precision manipulations without risking the sliding of said trocar in the abdominal wall. However, this inner tube device has a significant drawback. In fact, it is possible for the instrument to slide out of the trocar, or for the practitioner to remove this same instrument from the trocar, without an automatic and therefore systematic closure of the lips of the membrane occurring. in the situation where, the trocar being empty of instrument and the lips of the membrane open, no sealing is no longer ensured, with the consequences that one can imagine.

The method of automatic closure of a self-locking trocar according to the present invention aims in particular to remedy this drawback so as to ensure optimum security. To this end, the present invention relates to a method for automatically closing a self-locking trocar comprising a guide tube closed at its distal end by a membrane opening onto an introduction tube integral with said guide tube, the method being characterized in that, following a longitudinal push exerted at the proximal end of said trocar, push causing the opening of said membrane
- in the presence of an instrument pressed into the trocar at least up to the level of said guide tube, said trocar is armed, that is to say that the opening of said membrane is maintained, after the release of said thrust, and this, as long as said instrument remains inserted at least as far as the guide tube and the automatic closing of said membrane occurs as soon as said instrument is sufficiently withdrawn so that its distal end has left said guide tube and,
- In the absence of an instrument inserted into the trocar at least up to the level of said guide tube, the automatic and systematic closing of said membrane occurs as soon as said thrust is released.

 The invention also relates to a device implementing the method.

 The method according to the invention conventionally makes it possible to maintain the instrument, for example the perforation instrument inside the trocar, thanks to the firm pressure exerted by the lips of the membrane. This configuration is used, for example, when the practitioner, who is about to perform the perforation of the abdominal wall, manipulates the trocar in which the perforation instrument is threaded. By a simple arming of the trocar, operation which can be carried out using the single hand holding the trocar, the practitioner causes the opening of the lips of the membrane and is placed in the configuration of light maintenance where the instrument does is held more in its longitudinal movements than by the O-ring seal located at the proximal end of the trocar. The instrument therefore slides smoothly inside the trocar, thus providing great handling precision, while ensuring safety. total. Indeed, as soon as the instrument located inside the trocar in the armed position is removed from said trocar, the automatic closing of the lips of the membrane occurs ensuring sealing. Also, as it is impossible to arm the trocar when no instrument is inserted therein, the dangerous configuration constituted by an empty trocar in which the lips of the membrane would be kept open without positive intervention by the practitioner is strictly impossible.

An embodiment of the present invention will be described below, by way of non-limiting example, with reference to the attached drawing in which
FIG. 1 is a view in longitudinal section of a trocar according to the invention, empty and in the unarmed position,
FIG. 2 is a view in longitudinal section of an instrument inserted into the trocar according to the invention, in the unarmed position,
FIG. 3 corresponds to FIG. 2 after arming the trocar according to the invention,
FIG. 4 is a sectional view along the line IV-IV of FIG. 1,
- Figure 5 is a sectional view of a gas introduction valve in the trocar according to the invention.

 An example of a trocar implementing the automatic closing process according to the invention is shown in FIG. 1. It has an introduction tube 1 extending at its proximal end by a cylindrical sleeve 2 with a diameter normally greater than that of said introduction tube 1 and externally threaded.

This cylindrical socket 2 has a radial socket 3 intended for the introduction of the inert gas inside the peritoneum of the patient. An annular ring 4 of substantially cylindrical shape engages inside the sleeve 2; this annular ring 4 is closed by an elastic membrane 5 in the form of a cone, the apex of which is directed towards the insertion tube 1 and which is split into at least two identical lips so as to provide a passage for surgical instruments. The annular ring 4 is held inside said socket 2 by a cylindrical sleeve 6 internally threaded to be screwed around the socket 2 and thus enclose said annular ring 4. Said sleeve 6 is extended at its proximal part by a tube guide 7 having successively first and second collars 8, 9 and ending with a collar 10. The guide tube 7 has at its proximal end a radial groove 11 emerging through the second collar 9 and the collar 10 two lights diametrically opposite as shown in Figure 4. A pallet 12 is articulated by one of its ends on the guide tube 7 in which it is housed. It consists of a flat straight rod 12a, one of the faces 12b of which extends towards its articulated proximal end, by an inclined plane 12c which itself is extended by a spout 12d which is connected to the other face 12e of the rod 12a by a protrusion projecting from the surface of said face 12e and constituting the head 12f of said pallet 12.

Said head 12f has a normally semi-cylindrical shape and a transverse thickness slightly less than the width of one of said slots in the groove 11 in which it is fitted. An open circular ring 13 of diameter slightly greater than that of the guide tube 7 and inserted between the second collar 9 and the collar 10, passes through the head 12f of the pallet 12 through a through bore 14 formed in said head 12f according to a diameter greater than that of the section of said open ring 13, thus ensuring the articulation of said pallet 12 around said open ring 13. The mounting of said pallet 12 inside the guide tube 7 is carried out as follows: open ring 13 is forcibly mounted between the second collar 9 and the collar 10 then turned so as to make its opening coincide with one of the ends of the groove 11, the pallet 12 is then introduced into the proximal end of the guide tube 7 and its head 12f is inserted into the end of the groove 11 coinciding with the opening of the ring 13 with its beak 12d turned towards the inside of said guide tube 7. We then move apart slightly. rement the opening of the ring 13 and the bore 14 is made to coincide with the ends of the open ring 13. Then said open ring 13 which slips inside said bore 14 and is made to rotate around its axis, thus ensuring the fixing of the pallet 12 on said guide tube 7.An inner tube 15 is slidably mounted inside said guide tube 7 from which it protrudes at the proximal end of the trocar. Said inner tube 15 has at its distal part a first shoulder 15a carrying its outside diameter to the inside diameter of the guide tube 7 over a part 15b of length corresponding to the spacing between the cylindrical sleeve 6 and the first collar 8 of the guide tube 7. Said part 15b ends with a second shoulder 15c which reduces its outside diameter and is followed by a collar 15d and at the proximal end of said inner tube 15, by a collar 15e.

The inner tube 15 also has a recess 16 consisting of an axial oblong hole extending from the collar 15d, towards the distal end of said inner tube 15, over a width greater than that of the rod 12a of the pallet 12 Said inner tube 15 is slidably mounted inside the guide tube 7 so that the recess 16 coincides radially with the pallet 12 thus blocking said inner tube 15 in rotation and the length of the recess 16 is determined. so that said rod 12a can freely move inside said recess 16 regardless of the longitudinal position of said inner tube 15. The length of the inner tube 15 is determined so that when the shoulder 15a of said inner tube 15 abuts against the inner shoulder 17 provided inside the guide tube 7 at its junction with the sleeve 6, the collar 15d slightly exceeds the position longitudinal of the spout 12d of the pallet 12 and the distal free section of said inner tube 15 comes to cause the complete opening of the elastic membrane 5 by relative spacing of its lips. A first elastic annular sleeve 18 closes the trocar at its proximal end and secures the guide tube 7 and the internal tube 15. Said first elastic annular sleeve 18 has at its distal end a flange 18a forcibly mounted between the first collar 8 and the second collar 9 of said guide tube 7. The first elastic annular sleeve 18 is extended by a recess 18b covering the collar 9 and the flange 10 of the guide tube 7 and coming to press elastically on the head 12f of the pallet 12. The recess 18b is extended by a curved annular part 18c whose internal diameter is such that it does not come into contact with the inner tube 15. This curved annular part 18c is extended by a bead 18d constituting the proximal part of said first annular sleeve elastic 18 and having an inner groove 18e in which the collar 15e of the inner tube 15 is fitted. The bead 1 8d has a crown of inner radius smaller than the inner radius of said inner tube 15 constituting an O-ring 18f.

 The trocar according to the invention is shown in the rest position in FIG. 1. The recess 18b of the first annular sleeve 18 presses on the head 12f of the pallet 12 so as to tilt the rod 12a through the guide tube 7. The elastic restoring force exerted by the first elastic annular sleeve 18 is sufficient to maintain this inclination of the pallet 12 even when the trocar is in the inverted position with respect to that shown in FIG. 1, that is to say even when gravity tends to bring the rod 12a parallel to the guide tube 7. If, in the configuration shown in FIG. 1, where the trocar is empty of any instrument, the inner tube 15 is pushed along by its proximal end, c '' that is to say by pressing the proximal end of the first elastic annular sleeve 18, we will cause the sliding of said inner tube 15 whose shoulder 15a will abut against the shoulder 17 i inside the guide tube 7. In this position, the distal end of the inner tube 15 keeps the elastic membrane 5 open by relative spacing of its lips, but as soon as the pressure exerted at the proximal end of the first elastic annular sleeve is released 18, the inner tube 15 will be recalled back by the elastic force exerted by said first elastic annular sleeve 18 and in particular by its convex annular part 18c. In fact, during this entire operation, the pallet 12 will have retained its inclined transverse position inside the recess 16 formed in the inner tube 15. However, when said pallet 12 is thus inclined, its beak 12d is sufficiently distant from the axis of the trocar to allow the inner tube 15 to slide without the collar 15d coming up against said spout 12d. The sliding of said inner tube 15 is therefore completely free and as soon as the thrust is released, said tube 15 will return to its rest position, releasing the lips of the elastic membrane 5 which, in this way, will close again. absence of instrument inside the trocar and in the absence of positive thrust voluntarily maintained at the proximal end of said trocar, that the sealing of the insertion tube 1 towards the outside of said trocar is always ensured by the membrane elastic 4. When introducing an instrument through the proximal end of the trocar, shown in FIG. 2, said instrument will cause the rod 12a of the pallet 12 to rise up inside the recess 16 in parallel to the inner tube 15. The instrument will then move the lips 5 away from the elastic membrane 4 to penetrate the introduction tube 1. In this configuration not shown in the figure, the long hold Itudinal of the instrument inside the trocar is firm, because it is ensured by pinching the lips 5 of the elastic membrane 4 on the body of said instrument. This configuration is therefore particularly suitable when the practitioner is handling the trocar which has not yet been inserted inside the patient's body. In fact, the firm longitudinal support makes it possible to manipulate the trocar by holding it, for example, by the proximal end of the perforating instrument which has been introduced therein, without risking seeing said trocar sliding around said perforating instrument and falling . The practitioner can then arm the trocar. To do this, he will compress the first elastic annular sleeve 18 held by its collar 18a pressing on the index and middle fingers, pressing with the palm of the hand on the proximal end of the '' perforation instrument. I1 thus approximates the bead 18d of said sleeve 18 of said flange 18a by elastic deformation of said sleeve 18 and in particular, of the curved annular part 18c. This approximation of the bead 18d causes the inner tube 15 to slide by its collar 15e. The rod 12a of the pallet 12 being held parallel to the axis of the trocar by the body of the perforating instrument, the spout 12d has approached the axis of said trocar relative to the position where the pallet 12 is inclined inside the inner tube 15.When the inner tube 15 slides, the flange 15d abuts against the spout 12d which disappears by radial translation of the head 12f, translation authorized by the diameter of the bore 14 which has since it is greater than that of the diameter of the section of the open ring 13 and because of the radial elasticity of the recess 18b. The flange 15d having exceeded, in its longitudinal translation, the spout 12d, the latter is biased towards the axis of the trocar with the head 12f by the recess 18b of the elastic annular membrane 18, thus blocking the translation of the tube interior 15 in return as shown in FIG. 3. The flange 15d is arranged so that when it has just exceeded the longitudinal position of the nozzle 12d, the shoulder 15a of said interior tube 15 is almost in abutment the inner shoulder 17 of said guide tube 7 and the elastic membrane 4 is open.

The instrument, in this case the perforation instrument, is then no longer braked by the lips 5 of said elastic membrane 4, but only and slightly braked in translation by the O-ring 18f formed by the flange of the first annular sleeve elastic 18.

Said O-ring 18f then provides both a soft hold and a seal along the body of the perforating instrument. This gentle longitudinal support allows the practitioner to exercise precise gestures without causing significant effort, a potential source of shifting of the insertion tube 1 inside the patient's body.

When withdrawing the perforating instrument, when the end of the latter reaches the level of the first elastic annular sleeve 18, the rod 12a of the pallet 12 is returned to its transverse inclined position inside the inner tube 15 by the elastic force exerted by the recess 18d on the head 12f of said pallet 12. This rotation of said pallet 12 and therefore of its head 12f causes the spout 12d to move apart from the axis of the trocar, thereby freeing the flange 15d from the tube interior 15 which is then returned in the proximal direction by the elastic force of the first elastic annular sleeve 18 resulting from the decompression of its convex annular part 18c. The return of the inner tube 15 releases the lips of the elastic membrane 5 which thus close the annular ring 4 and again ensure sealing. Thus, even before the distal end of the perforating instrument has left the interior of the trocar and therefore that the sealing provided by the flange 18f has ceased, the elastic membrane 4 has closed again ensuring sealing. The entire operation was carried out without sealing interruption and completely automatically, without the intervention of the practitioner. We therefore have a trocar with automatic closure.

 It is quite clear that it remains entirely possible, as with a conventional trocar, to work with a firm hold of the instrument inside the trocar, while momentarily spreading the lips of the elastic membrane 5 to facilitate the passage of said instrument. For this purpose, it suffices to press voluntarily at the proximal end of the trocar so as to slide the inner tube 15 sufficiently inside the guide tube 7 to open the lips, without however going to the end of the stroke, that is to say without arming the trocar. I1 then suffices, after having moved the instrument inside the trocar, to release the pressure exerted at its proximal end so that the inner tube 15 returns to its rest position and the holding is again exerted by the lips on the body of said instrument. This is possible thanks to the dimensioning of the inner tube 15 which causes the lips of the elastic membrane 5 to open before the trocar is armed by snapping on the flange 15d behind the spout 12d of the pallet 12.

 The complete absence of a mechanical spring has an important advantage. Indeed, between each use, the entire trocar must be brought to high temperature in order to be sanitized. These significant variations in temperature, repeated many times, end up weakening the elastic metal parts. This problem becomes particularly acute because, due to the resistance of the hepatitis B virus up to 1500C, it is now necessary to practice rapid sterilization at 250 "C. This is why, according to a particular variant of the invention, provision is made to mount on the radial outlet 3 through which the neutral gas is introduced into the peritoneum, a valve 19 with rapid opening and closing comprising no mechanical spring.

Said valve 19, represented in FIG. 5 comprises a body 20, extended upstream, by a first end piece 21 intended to receive the gas supply pipe and extended downstream, by a second end piece 22 force-fitted in the radial socket 13. Said body 20 comprises a first cylindrical part 23 separated from the first end piece 21 by a first collar 24 and extended, beyond a shoulder 25 by a second cylindrical part 26 of larger diameter, coaxial with the first and separated from said second end piece 22 by a second collar 27. Said first cylindrical part 23 comprises a bore 23a opening upstream in said first end piece 21 and peripheral radial openings 23b opening at the bottom of said first bore 23a, said second cylindrical part 26 comprises a bore 26a opening out downstream in said second endpiece 22 and peripheral radial ports 26b opening at the bottom of said bore 26a. The body 20 slides inside a second elastic annular sleeve 28 comprising, upstream, a first internal ring 28a sliding just around the first cylindrical part 23 of the body 20 and downstream, a second internal ring 28b sliding just around of the second cylindrical part 26 of the body 20. Said second elastic annular sleeve 28 also includes a third internal ring 28c also sliding just around said first cylindrical part 23, disposed between the first internal ring 28a and the second internal ring 28b and separated from said inner ring 28a by a distance less than the distance separating the first collar 24 of the radial slots 23b from said first cylindrical part 23. The second and third internal ring 28b, 28c define a recess 28d of diameter greater than that of said second part cylindrical 26.In the open position, shown in Figure 5, the first internal ring 28a is in abutment against the first collar 24 and the radial slots 23b are uncovered by the third internal ring 28c, allowing the gas entering the end piece 21 through the bore 23a, to pass through said radial slots 23b to thus penetrate into the recess 28d and then pass through the radial openings 26> to emerge from the end piece 22 through the bore 26a and penetrate into the introduction tube 1 of the trocar by the radial socket 3 of the cylindrical sleeve 2. I1 is sufficient, to pass in the closed position, to slide the second elastic annular sleeve 28 around the body 20 to bring the third internal ring 28c into contact with the shoulder 25 and thus close the radial slots 23b.

The seal between the body 20 and the second elastic annular sleeve 28 is therefore ensured by the internal rings 28a, 28b and 28c which act as O-rings.

 The trocar according to the invention then has no elastic metal part since all of the spring and sealing functions are exerted by silicone means, namely, the first elastic annular sleeve 18, the second elastic annular sleeve 28 and the annular ring 4. These, by their structure, are perfectly resistant to sterilization at 250 "C and above all, given their low cost, can be changed at each operation at the cost of simple handling. Indeed, given their external position, said first and second elastic annular sleeves 18 and 28 can be removed and replaced in a few seconds by a manipulator having no particular knowledge of the trocar and without the aid of any tool. Similarly, changing the annular ring 4 requires only the unscrewing of the sleeve 6 of the cylindrical sleeve 2. It is quite clear that any elastomer having the same characteristics, in particular d elasticity and thermal resistance that silicone, would not depart from the scope of the invention.

Said first elastic annular sleeve 18 is provided for sealing around instruments with a diameter of 10 millimeters, that is to say that the diameter of its O-ring 18f is slightly less than 10 millimeters. Fittings are provided for working with instruments of smaller diameter, such as 5 millimeters for example. In this case, it should be noted that the geometry of the head 12f of the pallet 12 and in particular of its spout 12d ensures correct arming of the trocar, even if the pallet 12, in support, by its rod 12a on the body of an instrument of reduced diameter is not entirely parallel to the guide tube 7.

Claims (14)

 1 - Method for automatically closing a self-locking trocar comprising a guide tube (7) closed at its distal end by a membrane opening onto an introduction tube (1) integral with said guide tube (7), characterized in that, following a longitudinal thrust exerted at the proximal end of said trocar, thrust causing the opening of said membrane  - in the presence of an instrument pressed into the trocar at least up to the level of said guide tube (7), said trocar is armed, that is to say that the opening of said membrane is maintained, after the release of said as long as said instrument remains inserted at least into the guide tube (7) and said membrane is automatically closed as soon as said instrument is sufficiently withdrawn so that its distal end has left said guide tube (7 ) and,  - In the absence of an instrument inserted into the trocar at least up to the level of said guide tube (7), the automatic and systematic closing of said membrane occurs as soon as said thrust is released.  2 - Self-locking trocar with automatic closure comprising an introduction tube (1) extending at its proximal end by a cylindrical sleeve (2) with a diameter normally greater than that of said introduction tube (1), said cylindrical sleeve ( 2) being closed by an annular ring (4) held inside said sleeve (2) by a cylindrical sleeve (6) fixed around the sleeve (2), said sleeve (6) extending at its proximal part by the guide tube (7), device implementing the method according to the preceding claim characterized in that all the elastic return and sealing functions are exclusively provided by elastomer means.  3 - Self-locking trocar with automatic closure according to the preceding claim characterized in that the elastomer is silicone.  4 - Self-locking trocar with automatic closure according to any one of claims 2 or 3 characterized in that it comprises an inner tube (15) sliding coaxially inside said guide tube (7) to open said membrane (5 ), the proximal end of said inner tube (15) protruding from said guide tube (7), a valve (19) mounted in a radial socket (3) provided on the cylindrical sleeve (2) and in that said means silicone consist of  - the annular ring (4) closed by an elastic membrane (5) in the form of a cone, the apex of which is directed towards the introduction tube (1) and which is split into at least two identical lips so as to provide a passage for the surgical instruments,  a first elastic annular sleeve (18) fitted around the proximal end of the guide tube (7) and the proximal end of the inner tube (15), and  - a second elastic annular sleeve (28) constituting the outer wall of the valve (19).  5 - Self-locking trocar with automatic closure according to any one of claims 2,3 or 4 characterized in that said guide tube (7) successively comprises first and second collars (8, 9), a flange (10) and a pallet (12) articulated by one of its ends on the same guide tube (7), at the level of said second collar (9) and said collar (10), and in that the first elastic annular sleeve (18) recalls said pallet (12) in its rest position, inclined transversely across the inner tube (15).  6 - Self-locking trocar with automatic closure according to the preceding claim characterized in that the pallet (12) consists of a flat rectilinear rod (12a) of which one of the faces (12b) extends towards its articulated proximal end, by an inclined plane (12c) which itself is extended by a spout (12d) connected to the other face (12e) of the rod (12a) by a protuberance projecting from the surface of said face (12e) and constituting a head (12f ) normally semi-cylindrical in shape, housed in one of the two diametrically opposite openings defined in the second collar (9) and the flange (10) of the guide tube (7) by a radial groove (11) opening at the proximal end of said tube guide (7).  7 - Self-locking trocar with automatic closure according to the preceding claim characterized in that it comprises an open circular ring (13) of diameter slightly greater than that of the guide tube (7), inserted between the second collar (9) and the collar (10), said open circular ring (13) passing through the head (12f) of the pallet (12) by means of a through bore (14) formed in said head (12f) on a diameter greater than that of the section of said open ring (13), thus ensuring the articulation of said pallet (12) around said open ring (13) with its beak (126) facing the inside of the trocar.  8 - Self-locking trocar with automatic closure according to the preceding claim characterized in that the inner tube (15) has on its distal part a first shoulder (15a) increasing its outside diameter to the inside diameter of said guide tube (7) on a part ( 15b) of length corresponding to the spacing between the cylindrical sleeve (6) and the first collar (8) of the guide tube (7), part (156) terminated by a second shoulder (15c) reducing its outside diameter, followed of a collar (15d) and at its proximal end of a collar (15e).  9 - Self-locking trocar with automatic closure according to the preceding claim characterized in that the inner tube (15) has a recess (16) consisting of an axial oblong hole coinciding radially with the pallet (12) and extending from the collar ( 15d), towards the distal end of said inner tube (15), over a width greater than that of the rod (12a) of the pallet (12) which is housed therein and over a length such that said rod (12a) can freely debate inside said recess (16), regardless of the longitudinal position of said inner tube (15) which it thus blocks in rotation.  10 - Self-locking trocar with automatic closure according to the preceding claim characterized in that the length of the inner tube (15) is determined so that, before the shoulder (15a) of said inner tube (15) comes into abutment the inner shoulder (17) provided inside the guide tube (7) at its junction with the sleeve (6), the distal free section of said inner tube (15) comes to cause the complete opening of the membrane elastic (5) by relative spacing of its lips.  11 - Self-locking trocar with automatic closure according to the preceding claim characterized in that the first elastic annular sleeve (18) has at its distal end a flange (18a) forcibly mounted between the first collar (8) and the second collar (9) of said guide tube (7), said collar (18a) extending by a recess (186) covering the collar (9) and the collar (10) of the guide tube (7) and coming to bear elastically on the head ( 12f) of the pallet (12), said recess (18b) extending by a curved annular part (18c) whose internal diameter is such that it does not come into contact with the inner tube (15), said curved annular part (18c) being extended by a bead (18d) constituting the proximal part of said first elastic annular sleeve (18) and having an internal groove (18e) in which is fitted the flange (15e) of the inner tube (15).  12 - Self-locking trocar with automatic closure according to the preceding claim characterized in that the bead (186) of the first elastic annular sleeve (18) has a crown of inner radius smaller than the inner radius of said inner tube (15) said crown thus constituting a seal toric (18f).  13 - Self-locking trocar with automatic closure according to any one of claims 4 to 12 characterized in that the valve (19) comprises a body (20), extended upstream by a first end piece (21) and extended downstream by a second end piece (22) forcibly mounted in the radial socket (13), said body (20) comprising a first cylindrical part (23) separated from the first end piece (21) by a first collar (24) and extended, beyond a shoulder (25) by a second cylindrical part (6) of larger diameter, coaxial with the first and separated from said second end piece (22) by a second collar (27), said first cylindrical part (23) having a bore (23a) opening downstream in said first endpiece (21) and peripheral radial openings (23b) opening out at the bottom of said first bore (23a), said second cylindrical part (26) having a bore (26a) opening upstream in said second endpiece (22 ) and radial lights (26h) per iphérique opening at the bottom of said bore (26a), said body (20) sliding inside the second elastic annular sleeve (28).  14 - Self-locking trocar with automatic closure according to the preceding claim characterized in that the second elastic annular sleeve (28) comprises, upstream, a first internal ring (28a) sliding just around the first cylindrical part (23) of the body (20 ) and downstream, a second internal crown (28b) sliding just around the second cylindrical part (26) of the body (20), a third internal crown (28c) also sliding just around said first cylindrical part (23), arranged between the first internal ring (28a) and the second internal ring (28b), and spaced from the first internal ring (28a) by a distance less than the distance between the first collar (24) and the radial slots (23b) of said first cylindrical part (23), said second inner ring (28b) and third inner ring (28c) defining a recess (28d) of diameter greater than that of said second cylindrical part eu (26).