Patent Publication Number: US-2022234799-A1

Title: Tube closure assembly and tube comristing the same

Description:
The present invention relates to an assembly for closing a tube and a tube comprising this assembly. 
     Tubes are known which are provided with a lid associated with a perforating cap comprising a punch adapted to perforate said lid. 
     The lid allows the product contained in the tube to be kept hermetically sealed during its storage prior to its first use, which represents a very important part of the overall life of the tube. 
     There are caps in which the punch is placed in the cap and protrudes from it so that it can perforate the cap when the cap is screwed onto the tube head. In order to ensure the preservation of the seal prior to the first use, a ring is arranged between the cap and a shoulder of the tube head, so as to keep the punch away from the seal when the cap is screwed onto the neck. In this position, the cap is in a so-called transport position or waiting position before first use. 
     To pierce and/or cut the cap, the user must first unscrew the cap, then remove the ring and finally screw the cap back on until the cap is pierced and/or cut once it has reached an end position, also known as the closing position. The number of steps is restrictive for the user, who often does not understand what the ring is for, nor does he necessarily understand that a cap must be pierced before the tube is used for the first time. 
     It is known from document LU 88845 that a cap with a punch is held in the standby position without a removable ring. The neck comprises a housing in which a portion of thread, located on the cap, can be locked in such a position. The threaded portion is then used to screw the cap onto the neck to a position where the cap can be pierced and cut off when the tube is first used. The cap can then be screwed or unscrewed for later use or left in place when fitted with a reclosable dispensing system such as a service cap. However, this device has various drawbacks. 
     First of all, the placing of the cap on the neck in the waiting position is carried out according to processes operating at a very high rate. It is therefore necessary for this operation to be carried out with a high degree of reliability in order to provide satisfactory repeatability. 
     With the device of document LU 88845, a rib serving to snap the thread portion into the housing enabling it to be held in the standby position is produced by radial deformation of the cap. The manufacturing tolerances remain relatively high, typically greater than a tenth of a millimetre, in such a direction, which is detrimental to the ability to obtain the desired locking effect on all the caps produced, particularly in the case of demoulding with slides. 
     To overcome this first drawback, the present invention proposes, according to a first aspect, an assembly for closing a tube, said assembly comprising a tube head, provided with a neck, and a cap, said assembly defining a guide path, a thread and a thread portion allowing the cap to be placed on the neck by cooperation with the guide path and the thread, said assembly comprising a first and a second stop for said thread portion, said stops being angularly spaced and defining a passage between the guide path and the thread, said assembly being configured to allow axial displacement of the thread portion through the passage with a non-return effect by at least one of said stops. 
     According to this first aspect of the invention, the stops allowing the cap to be positioned at the desired location while preventing its return to the previous configuration, in particular a configuration in which the cap can be disengaged from the neck, are angularly positioned with respect to each other. In this way, the size of the corresponding passage is more precisely controlled, particularly in the case of a closure and a neck demoulded with slides. This provides a manufacturing process with improved repeatability. 
     According to this first aspect, the invention may also comprise any of the following features, taken individually or in any technically possible combination forming as many embodiments of the invention, this including with the features of the other aspects of the invention set out below:
         said tube head is further provided with a cap closing said neck,   said cap is provided with a punch adapted to perforate said cover,   said neck and said cap are configured to guide the cap from an initial position in which the cap is not engaged with the neck to a waiting position in which the punch is kept at a distance from said cover, in particular after the thread portion has passed through said passage, and then from said waiting position to a closing position in which said punch has perforated said cover   said guide path allows the passage from the initial position to the waiting position and said threading allows the passage from the waiting position to the closing position,   one of the two between the guide path and the thread induces a screwing in a clockwise direction of rotation of the cap, the other of the two between the guide path and the thread inducing a screwing in a counter-clockwise direction of rotation of the cap,   the guide path induces counterclockwise rotation of the cap and the thread induces clockwise rotation of the cap,   the neck comprises the guide path and the thread and the cap comprises the thread portion,   the first stop forms an end of said guide path,   said assembly comprises a shoulder connecting an origin of a first thread of the thread and the first stop,   the second stop is formed by an axial wall,   the second stop forms the origin of a second thread of the thread,   said assembly comprises a third stop configured to block a screwing of the cap after placing the cap on the neck,   said third stop comprises a wall, extending transversely from a bottom wall of the thread,   said wall extends axially partially through said thread,   an angular extension between the second and third stop is just greater than an angular extension of the thread portion.       

     A further drawback of the device of LU 88845 is the torque required to successfully close the cap on first use. Indeed, with the cap used in this document, it is necessary to simultaneously pierce the cap and compress a seal ensuring a tight closure of the cap. Such a torque may cause discomfort to the user. 
     To overcome this other drawback, the present invention proposes, according to a second aspect, an assembly for closing a tube, said assembly comprising a tube head provided with a neck and a cap closing said neck, said assembly further comprising a stopper provided with a punch adapted to perforate said cap, said neck and said stopper being configured to guide the stopper on the neck to a closing position in which the cap has perforated the lid, passing through an intermediate position in which the punch has finished perforating said lid, as well as to cause a deformation of the material sealing the closure, said assembly being configured so that the passage through the intermediate position takes place prior to the deformation of the material sealing the closure. 
     By material deformation is meant, for example, material crushing or the like causing a seal. 
     According to this second aspect of the invention, by sequencing the operations corresponding on the one hand to the drilling and on the other hand to the compression of the material making it possible to seal the closure, a configuration is obtained in which the torque to be exerted is more constant throughout the placing of the cap on the neck, which is more comfortable for the user. In fact, the deformation of the material used for sealing only takes place once the drilling of the cap has been completed. In other words, during the deformation used for sealing, a cut in the lid may take place at the same time, but its drilling has already taken place. In particular, in the case of a punch provided with a plurality of teeth, all the teeth have pierced the said lid. 
     According to this second aspect, the invention may also comprise any of the following features, taken individually or in any technically possible combination forming as many modes of implementation of the invention, this including with the features of the other aspects of the invention set out in the foregoing or in the following:
         the cap is screwed onto the neck when passing through the intermediate position and up to the closing position,   said neck and said cap are configured to guide the cap from an initial position in which the cap is not in engagement with the neck to a waiting position in which the punch is held at a distance from the lid, then from said waiting position to said closing position, in particular by screwing   said cap and said neck are configured so that said intermediate position is located downstream of the waiting position in the direction in which the cap is guided towards the closure position,   said assembly comprises a thread portion and a thread for screwing the cap onto the neck,   said assembly comprises a stop configured to block the screwing of the cap in said waiting position, said assembly being configured so that said thread portion has passed said stop before the piercing of the cap starts,   said assembly further comprising an anti-return stop configured to prevent the cap from leaving the closure position, said assembly being configured so that said stop is passed after passing into an intermediate position,   the punch comprises a plurality of teeth, said intermediate position being the position occupied by the punch when all the teeth have pierced said cap,   said punch comprises a base having an external cylindrical portion and said neck comprises an internal cylindrical portion,   said inner and outer cylindrical portions are intended to be crushed against each other to achieve the sealing of said closure,   said cap comprises an apex from which said punch base extends, said punch comprising an external chamfer extending said base and connected to a distal part of the punch,   said portion of the neck against which the base of the punch is intended to crush is located in axial extension of a chamfer, located at an open end of the neck   said distal part of the punch has an external diameter smaller than an internal diameter of the neck.       

     According to another drawback of the device of document LU 88845, the stopper comprises a non-return stop allowing to maintain the stopper in place once in the closed position. However, this stop is located in the thread used to guide the cap on the neck and the portion of the thread used to screw the cap on has to force its way over this stop. This can damage the stop and requires additional torque to be applied by the user. This stop can also give the user the impression of a hard point corresponding to the end of the stroke marking the closure of the cap when this is not yet the case. The perforation of the cap by the punch may not be completed, which will hinder the proper flow of the product contained in the tube. There is also a risk that the seal will not be completely achieved. 
     To overcome this other drawback, the present invention proposes, according to a third aspect, an assembly for closing a tube, the said assembly comprising a tube head provided with a neck and a cap closing the said neck, the said assembly also comprising a stopper comprising a punch adapted to perforate the said cap, said neck and said cap being configured to guide the cap to a closure position in which said punch has perforated said cover, said cap comprising a lateral skirt provided with at least one notch opening radially, said neck comprising a protrusion configured to cooperate angularly with said notch to block withdrawal of the cap, once said cap is in said closure position. 
     According to this third aspect of the invention, the protrusion for blocking the cap in the closed position does not come into contact with the shapes used to guide the cap to its closed position. Instead, it is located at a distance from and cooperates with a specific shape, namely the notch provided in the cap to effect the desired locking. In this way, damage to the shapes used to guide the cap on the neck is avoided and the correct identification of the end position is made reliable. 
     According to this third aspect, the invention may also comprise any of the following features, taken individually or in any technically possible combination forming as many modes of implementation of the invention, including with the features of the other aspects of the invention set out in the foregoing or in the following:
         said notch is open at a free edge of said skirt so as to impart radial resilience to the cap in the vicinity of said notch,   said protrusion is configured to radially spread said skirt before the plug arrives in the closed position,   said protrusion has an edge provided with an inclined portion and a straight portion, said inclined portion being configured to radially spread said cap and said straight portion being located at a part of the protrusion forming a non-return stop for the cap once in the closure position,   said assembly comprises a thread and a thread portion configured to co-operate with said thread for screwing the plug to said closure position,   said assembly is configured for said thread portion to reach said closure position by passing away from said protrusion,   said protrusion extends axially from a terminal end of a lower thread of the thread,   said assembly further comprises an end stop for the plug in the closed position,   said assembly further comprises an end stop for the plug, in the closed position, the end stop is configured to cooperate with said thread portion, once said protrusion is engaged in one of said notches,   said assembly comprises a plurality of said notches and a plurality of said thread portions, each of said thread portions being angularly located between two adjacent ones of said notches,   said cap comprises a service cap.       

     According to another drawback of the device of LU 88845, the punch protrudes into the interior volume of the receptacle in the closure position of the cap. This limits the rate of product return. Indeed, the product located in the receptacle at the level of the punch is blocked by the latter and cannot penetrate into the neck. 
     To overcome this other drawback, the present invention proposes, according to a fourth aspect of the invention, an assembly for closing a tube, the said assembly comprising a tube head provided with a neck and a cover closing the said neck, the said assembly also comprising a stopper provided with a punch adapted to perforate the said cover, said neck and said cap being configured to guide the cap to a closure position in which said punch has perforated said cover, said punch comprising one or more cover-cutting teeth extending from a free edge of the punch, at least one angular portion of said free edge, called the passage portion, being configured to remain in the neck in said closure position. 
     According to this fourth aspect of the invention, an angular portion of the punch does not penetrate the tube and therefore nothing opposes the flow of the product which can thus be more completely distributed. 
     According to this fourth aspect, the invention may also comprise any of the following features, taken individually or in any technically possible combination forming as many embodiments of the invention, this including with the features of the other aspects of the invention set out in the foregoing or following:
         said passage portion of the free edge of the punch is flush with a lower end of the neck,   said teeth are distributed over an angular portion of the punch, called the cutting portion, delimited by two of said teeth located angularly on either side of said cutting portion, said passage edge being formed by an angular portion of the punch complementary to said cutting portion   said teeth have vertices that are axially offset from one another,   the axial offset of the tops of the teeth is increasing in a direction of movement of the plug towards said closing position,   said teeth have a substantially identical height and extend axially from an angular portion of the free edge having an axial offset from one tooth to the other   said teeth have a substantially identical profile,   said cap is located at the bottom of the neck,   said cap is screwed onto said neck over at least part of its travel,   said cap comprises a service cap.       

     It should also be noted that, according to another aspect, the invention concerns an assembly for closing a tube, said assembly comprising a tube head provided with a neck and a cap closing said neck, said assembly further comprising a cap provided with a punch adapted to cut said cap, said neck and said cap being configured to guide the cap to a closing position in which said punch has perforated said cap, said punch comprising a plurality of lid cutting teeth extending from a free edge of the punch, said teeth having apices axially offset from each other, said teeth having a substantially identical height and extending axially from an angular portion of the free edge having an axial offset from one tooth to the other. 
     According to this aspect of the invention, an axial offset of the top of the teeth is achieved without having to employ smaller and therefore more fragile teeth than others. 
     The invention also relates to a tube comprising a closure assembly as described above. 
    
    
     
       Further features, purposes and advantages of the invention will be apparent from the following description, which is purely illustrative and not limiting, and which should be read in conjunction with the appended drawings, in which: 
         FIG. 1  is a perspective view of a tube head for a tube closure assembly according to a first embodiment of the invention, from a first viewing angle, 
         FIG. 2  is a perspective view of the tube head of  FIG. 1  from another view angle, 
         FIG. 3  is a side view of the tube head of  FIG. 1  from the first viewing angle 
         FIG. 4  is a side view of the tube head of  FIG. 1  from the other view angle 
         FIG. 5  is a side view of an assembly according to the invention comprising the head of  FIG. 1  and a plug illustrated in transparency, according to the first angle of view, in a first position of the plug, 
         FIG. 6  is a side view of the assembly of  FIG. 5  from the other viewing angle, in the first position of the cap 
         FIG. 7  is a side view of the assembly according to  FIG. 5 , from the first viewing angle, in a second position of the cap, 
         FIG. 8  is a side view of the assembly according to  FIG. 5 , from the other view angle, in the second position of the cap, 
         FIG. 9  is a side view of the assembly according to  FIG. 5 , from the first viewing angle, in a third position of the cap, 
         FIG. 10  is a side view of the assembly according to  FIG. 5 , from the other view angle, in the third position of the cap, 
         FIG. 11  is a side view of the assembly according to  FIG. 5 , from the first viewing angle, in a fourth position of the cap, 
         FIG. 12  is a side view of the assembly according to  FIG. 5 , from the other view angle, in the fourth position of the cap, 
         FIG. 13  is a side view of the assembly according to  FIG. 5 , from the first viewing angle, in a fifth position of the cap, 
         FIG. 14  is a side view of the assembly according to  FIG. 5 , from the other angle of view, in the fifth position of the cap, 
         FIG. 15  is a side view of the assembly according to  FIG. 5 , from the first viewing angle, in a sixth position of the cap, 
         FIG. 16  is a side view of the assembly according to  FIG. 5 , from the other angle of view, in the sixth position of the cap, 
         FIG. 17  is a diametrical cross-sectional view of the assembly according to  FIG. 5  in the fourth position of the cap, 
         FIG. 18  is a diametrical cross-sectional view of the assembly according to  FIG. 5  in the fifth position of the cap, 
         FIG. 19  is a diametrical cross-sectional view of the assembly according to  FIG. 5  in the fifth position of the cap, 
         FIG. 20  is a perspective view of a distal edge of a punch of the plug of the assembly of  FIG. 5 , the orientation of the plug having been reversed from the previous figures. 
     
    
    
     As illustrated in  FIGS. 1 to 19 , the invention relates to an assembly for closing a tube, in particular a flexible tube. 
     Said assembly comprises a tube head  3  and a cap  30 . The tube head  3  comprises a neck  10  and a cap  5  closing said neck  10 , here at the bottom of the latter. In other words, the cap is disposed at the end of the neck in fluid communication with the tube reservoir. The cap  30  comprises a punch  7  adapted to perforate said cover  5 . Said punch  7  is in particular configured to pierce and then cut said cover  5 . Advantageously, said cover is only partially cut so that it remains attached to the tube head  3  by a portion of material. 
     The neck  10  and the cap  30  extend substantially along a longitudinal axis A (see  FIG. 17 ) passing through their centre. In the following, the term “axial” is understood to be oriented parallel to the said longitudinal axis A. The cap  30  is rotatable and/or translatable relative to said neck  10  along said longitudinal axis A. 
     Said neck  10  and said cap  30  are configured to allow the cap  30  to be guided, in particular from an initial position, illustrated in  FIGS. 5 and 6 , to a waiting position, illustrated in  FIGS. 9 and 10 , and then from said waiting position to a closing position, illustrated in  FIGS. 15 and 16 . 
     When the cap  30  is in its initial position, said cap  30  is not in engagement with the neck  10 . Said cap  30  is in this initial position at the beginning of the movement of placing the cap  30  on the tube head  3 . This placement, also known as capping, is carried out in particular on production lines. It is therefore important to allow simple, reliable and repeatable kinematics in order to limit production incidents. Advantageously, when the cap  30  is placed on the tube head  3 , on production lines, the cap  30  is guided on the neck  10  along a guide path  21  along which it is simultaneously pushed towards the tube head and rotated counter-clockwise. 
     When the cap  30  is in the waiting position on the neck  10 , the punch  7  is held at a distance from the lid  5 . Said cap  30  is in this standby position at the end of the initial movement of placing the cap  30  on the tube head  3 . It is in this position that the assembly is sold before filling the tube. It is also in this waiting position that the assembly is sold to the consumer, after the tube has been filled. Such an assembly ensures that it is held in the standby position without the use of an additional part such as a spacer ring. 
     As illustrated in  FIGS. 15, 16 and 19 , when the cap  30  is in the closed position, said punch  7  has perforated said lid  5 . The cap  30  then hermetically seals the tube on which the assembly is fitted. The closed position can also be described as a position of use in that the cutting of the cover  5  determines the starting point for the use of the tube on which the closure assembly  1  according to the invention is mounted. The cap  30  may in particular be intended to remain in the closed position. This is particularly the case when the punch  7  has the shape of a hollow barrel and has an opening, not illustrated, at the upper side of the cap  30 . Thus, once the cap  30  is in the closed position on the neck  10 , access to the internal volume of the tube on which the assembly is fitted is possible through said opening. According to an embodiment not shown, the opening of the neck  30  is closed by a lid connected to the stopper  10 , the stopper and the lid possibly forming a service cap. In this way, the cap  30  can be held in the closed position on the neck  10  while allowing access to the internal volume of the tube and the closure of this access. 
     In addition to said guide path  21 , said assembly comprises a thread  22  and a thread portion  11  allowing the cap  30  to be placed on the neck  10  by cooperation with the guide path  21  and the thread  22 . The guide path  21  and the thread  22  are more particularly visible in  FIGS. 1 to 4  while the thread portion  11  is more particularly visible, in transparency, in  FIGS. 5 to 16 . 
     As more particularly illustrated in  FIGS. 5 and 6 , when guiding from the initial position to the standby position, said thread portion  11  co-operates with the guide track through a front end  12  of said thread portion  11 . 
     As more particularly illustrated in  FIGS. 11 to 16 , said thread portion  11  is intended to cooperate with said thread  22  by screwing. 
     Said cap comprises a lateral skirt  23  having an inner face at which said thread portion  11  is located. Said thread portion  11  has a substantially trapezoidal cross-section, intended to cooperate with the thread  22 . Said thread portion  11  extends longitudinally along the axis A, radially inwardly of the cap  30  from the skirt  23  and angularly between its front end  12  and a rear end  13 . The angular span of said thread portion is, for example, between 30 and 90°. 
     According to a first aspect of the invention, said assembly comprises a first stop  24  and a second stop  25  for said thread portion  11 . Said stops are angularly spaced and define a passage  26  between the guide track  21  and the thread  22 . Said assembly is configured to allow axial movement of the thread portion  11  through the passage  26 . Furthermore, once said passage  26  is passed by said thread portion  21 , at least one of said stops, here the first stop  24  is configured to prevent a return of said thread portion  21  through said passage  26 . The cap  30  is then blocked on the neck  10  by snap-fit and can no longer be disengaged from the neck  10 . 
     Such kinematics makes it possible to clearly identify the arrival in the waiting position by modifying the trajectory of the cap  30 , which passes here from a movement including a rotation along the guide path  21  to an axial movement to cross the said passage  26 , rather than kinematics according to which the arrival in the waiting position is done in the continuity of a screwing. Furthermore, the neck  10  has an outer wall  14  which remains smooth without ribs or grooves at said passage  26 , the snap-in effect of said thread portion  11  being solely due to the angular span of said passage  26 , which is chosen to be smaller than a span of said thread portion  11 . The accuracy of such ribs is more easily controlled than a radial rib and may be less than a tenth of a millimetre, in particular in the case of injection moulding of said tube head  3  and/or said cap  30 . 
     In the illustrated embodiment, said plug is in said waiting position after passing through said passage  26 . In other words, said guide path  21  allows the passage from the initial position to the waiting position and said thread  22  allows the passage from the waiting position to the closing position. 
     Advantageously, one of the two between the guide path  21  and the thread  22  induces a screwing in a clockwise rotation direction of the cap  10 , the other of the two between the guide path  21  and the thread  22  inducing a screwing in a counterclockwise rotation direction of the cap  10 . Here, the guide path  21  induces a counterclockwise rotation of the cap  10  and the thread  22  induces a clockwise rotation of the cap  10 . 
     Preferably, the neck  10  comprises the guide path  21  as well as the thread  22  while the cap  30  comprises the thread portion  11 . 
     Here, the first stop  24  forms one end of said guide path  21 . Said assembly further comprises a shoulder  27  connecting an origin of a first thread  28  of the thread  22  and the first stop  24 . Thus, the origin of the first thread  28  and the first stop  24  are axially spaced apart. In particular, the first stop  24  forms a rounding joining said guide track  21  and said shoulder  27 . 
     The second stop  25  is formed, for example, by an axial wall. The second stop  25  forms the origin of a second thread  29  of the thread  22 . 
     Said second thread  29  advantageously forms a low axial stop when said thread portion  11  passes through said passage  26 . 
     Preferably, said assembly comprises a third stop  31  configured to block a screwing of the cap  30  after the cap  30  has been placed on the neck  10  and more precisely, here, when said cap  30  is in the waiting position. 
     In other words, in the waiting position, the thread portion  11  is blocked axially upwards by the first stop  24  and downwards by the second thread  29 , unscrewing by the second stop  25  and screwing by the third stop  31 . 
     In  FIGS. 7 and 8 , the thread portion  11  is passing through the passage  26 , while in  FIGS. 9 and 10 , said thread portion  11  is positioned between the various stops mentioned in the previous paragraph. 
     Said third stop  31  comprises, for example, a wall  32 , extending transversely from a bottom wall of the thread  22 . Said wall  32  has here a constant thickness. Said assembly has a sharp angle between the wall  32  and the second thread  29 . Said wall  32  extends radially between a bottom of the thread  22  and a free distal edge and axially between said second thread  29  and a free radial edge. Preferably, said wall  32  extends axially partially through said thread  22 . The axial extension of said wall  32  allows to adjust the torque required to pass said third stop  31 . 
     Preferably, an angular extension between the second  25  and third  31  stops is just greater than an angular extension of the thread portion  11 . Said third stop  31  is here positioned under said first thread  28  being slightly angularly offset from said first stop  24  in the screwing direction. 
     Said guide path  21  is formed, for example, by a third thread ending on the first stop  24 . 
     Once said third stop  31  is passed, said thread portion  11  is configured to slide by screwing between the first  28  and second  29  threads. 
     In the further movement of the cap  30 , said neck  10  and said cap  30  are configured to guide the cap  30  on the neck  10 , here by screwing, to the closing position through an intermediate position, illustrated in  FIGS. 13 and 14 , in which the punch has finished piercing said lid  5 . In the case where, as illustrated, the punch  7  comprises several teeth  50 , said intermediate position is the position occupied by the punch  7  when all the teeth  50  have pierced said cover  5 . 
     Furthermore, as already mentioned, said neck  10  and said cap  30  are configured so that guiding, here screwing, the cap  30  onto the neck  10  causes a deformation of material making the closure tight. 
     According to a second aspect of the invention, said assembly is configured so that the passage through the intermediate position takes place prior to the deformation of the material sealing the closure. Such a configuration is obtained by the choice of the axial dimensions of the punch  7  and neck  10 . Such a sequencing avoids having to provide too much torque compared to a configuration in which the sealing would start before the end of the drilling. On the other hand, the seal can be made when the lid  5  is cut, after the end of the drilling. It has in fact been noted by the applicant that the torque required for cutting is much lower than that for drilling. 
     Advantageously, the said cap  10  and the said neck  30  are configured so that the said intermediate position is located downstream of the waiting position according to the direction of guidance, in particular screwing, of the cap  30  towards the closure position. In other words, in the example illustrated in relation to the first aspect of the invention, said assembly is configured so that said thread portion  11  has passed said third stop  31  before the piercing of the cap begins. 
     Taking  FIGS. 11 and 12  and  FIG. 17  in combination, it can be seen that the punch  7  comes into contact with the lid  5  while the thread portion  11  is still interacting with the third stop  31 . However, the drilling of the lid  5  does not begin immediately after the screwing movement. The reason for this is that the lid  5  is elastic, so that it is deformed before it is pierced. Thus, drilling only begins in a position between that shown in  FIGS. 11 and 12  and that shown in  FIGS. 13 and 14 . 
     Advantageously, as will be developed below in relation to the third aspect of the invention, said assembly further comprises a non-return stop  33  configured to prevent the cap  30  from moving out of the closed position. Even more advantageously, said assembly is configured so that said non-return stop  33  is passed by the plug  10  after passing to the intermediate position. In other words, as illustrated in  FIGS. 13 and 14 , said cap  10  does not yet cooperate with said non-return stop  33  when the cap  10  is in said intermediate position. 
     The sealing of the closure may be achieved in different ways. Here, it is a seal obtained by cooperation of an inner wall of the neck  10  and an outer wall of the punch  5 . 
     As illustrated in  FIGS. 17 to 19 , the said punch  7  comprises a base  34  with an external cylindrical portion  35  and the said neck comprises an internal cylindrical portion  36 , the said internal and external cylindrical portions  36  and  35  being intended to be crushed against each other in order to seal the said closure. In this way, a cylinder-to-cylinder seal is achieved, which has the advantage of requiring less torque than that required for the compression of a seal which would be located on an upper free edge of the neck. 
     Said cap  30  here comprises a top  37  from which said base  34  of the punch  7  extends. Said punch  7  further comprises an external chamfer  38  extending said base  34  and connected to a distal portion  39  of the punch  7 . Said neck  10  comprises at its externally open end an internal chamfer  40  axially extended by said portion  36  of the neck  10  against which the base  34  of the punch  7  is intended to be crushed. 
     In  FIG. 17 , upstream of the intermediate position, according to the screwing direction of the cap  30 , it can be seen that the chamfer  38  of the punch is axially at a distance from the chamfer  40  of the neck. In  FIG. 18 , in the said intermediate position, the chamfer  38  of the punch has just come to rest against the chamfer  40  of the neck. In  FIG. 19 , in the closed position, a compression of material has occurred between the base  34  of the punch and the corresponding portion  36  of the neck  10 . 
     Advantageously, in order to limit the necessary torque, said distal portion  39  of the punch has an external diameter smaller than an internal diameter of the neck  10 . 
     According to a third aspect of the invention, the lateral skirt  23  is provided with at least one notch  60  opening radially and said neck  10  comprises a protrusion  61  configured to cooperate angularly with said notch  60  to block a withdrawal of the cap  30 , once said cap is in said closure position. Said protrusion  61  forms the aforementioned non-return stop  33 . 
     Such a non-return stop  33  has the advantage of not being located in the thread  23 . It is therefore not likely to be damaged by the thread portion  11  when the latter moves to the closed position. In other words, in the illustrated embodiment, said thread portion  11  reaches said closing position by passing away from said protrusion  61 . 
     Preferably, said notch  60  is open at a free edge of said skirt  23  so as to give radial resilience to the cap  30  in the vicinity of said notch  60 . Such resilience has many advantages. First of all, it limits the torque required to reach the closed position by overcoming said non-return stop  33 . In addition, it facilitates an axial demoulding of the thread portion  11 . The notch  60  is, for example, substantially rectangular. 
     Advantageously, said protrusion  61  is configured to radially spread said skirt  23  before arrival of the cap  30  in the closed position. For this purpose, the said protrusion has an edge provided with an inclined portion  62  and a straight portion  63 . Said straight portion  63  axially extends the inclined portion  62  towards a base of the neck  10 . Said inclined portion  62  is configured to radially spread said cap  10  by pressing on a free edge of said skirt  23  before the cap  10  arrives in the closed position. Said straight portion  63  is located at a part of the protrusion  60  forming the non-return stop  33  for the cap  10  once in the closed position. More precisely, the notch  60  has an axial edge  64  bearing against a flank of said protrusion  33 , the latter forming said non-return stop  33 . 
     The protrusion  61  is formed, for example, by a wall extending radially from the outer wall  14  of the neck. Said wall has an upper free edge  65  terminating the second thread  29 . Said protrusion  61  extends axially from the terminal end  65  of said second thread  29 , here forming a lower thread of the thread  22 , to the base of the neck  10 . Said non-return stop  33  is intended to cooperate with the rear end  13  of the thread portion  11 . 
     Advantageously, said assembly further comprises an end-of-stroke stop  70 , in particular an angular stop, for the cap  10 , in the closed position. Said limit stop  70  is configured to cooperate with said thread portion  11 , once said protrusion  61  is engaged in said notch  60 . Said end stop  70  is intended to cooperate with the front end  12  of the thread portion  11 . Said return stop  70  extends here axially between the first thread  28  and the base of the neck. 
     In the illustrated embodiment, said assembly comprises a plurality of said thread portions  11  and a corresponding plurality of said threads  22 , in this case three, spaced at 120°. Said assembly further comprises a plurality of said notches  60  and a corresponding plurality of said protrusions  61 , in this case three, each of said thread portions  11  being angularly located between two neighbours of said notches  61 . Said side skirt  23  thereby has flaps having good radial flexibility between said notches  60 , said thread portions being located at said flaps. 
     In this configuration with several threads  22 , the first thread  28  of one of the threads forms the second thread  29  of the adjacent thread  22 . 
     At the top, the second stops  25  extend axially between an origin of the third thread forming the guide path  21  associated with one of the threads  22  and the second thread  29  of the adjacent thread  22  in a clockwise direction. 
     At the bottom, the end stop  70  of one of the threads  22  is located angularly, clockwise, just upstream of the protrusion  60  of the counterclockwise adjacent thread  22 . The first thread  28  of one of the threads  22  continues into an end portion of the second thread  29  of the counterclockwise adjacent thread  22 . 
     As illustrated in  FIGS. 17 to 20 , said tooth or teeth  50  are advantageously configured to pierce and then cut said lid  5 . Said tooth or teeth  50  extend from a free edge  80  of the punch  7 . 
     According to a fourth aspect of the invention, at least one angular portion  81  of said free edge  80 , referred to as the passage portion, is configured to remain in the neck  10  in said closing position as is more particularly apparent from  FIG. 19 . Such a configuration improves the rate of restitution of the product contained in the tube by allowing a fraction of the product located in the vicinity of a shoulder  4  of the tube head  3  to flow into the neck  10  at the level of said passage portion  81 . Advantageously, said passage portion  81  is flush with a lower end of the neck  10  opening into the interior volume of the tube. 
     Here, the said teeth  50  are distributed over an angular portion  82  of the punch  7 , known as the cutting portion, delimited by two of the said teeth  50  located angularly on either side of the said cutting portion  82 . Said passage edge  81  is formed by an angular portion of the punch complementary to said cutting portion  82 . 
     As is better illustrated in  FIG. 20  where a fictitious plane P extending orthogonally to said longitudinal axis A has been shown, said teeth  50  have vertices  51  axially offset from each other. Such a configuration makes it possible to limit the screwing torque by ensuring that the teeth  50  pierce the cover  5  successively. The axial offset of the tops of the teeth  50  increases, in particular regularly, and even more particularly linearly, in a direction of displacement of the cap  10  towards the said closed position, in other words, here, according to the screwing direction or clockwise direction (which corresponds to an anti-clockwise direction in  FIG. 20  since the latter is reversed). Thus, the tooth  50  located at a terminal end of the cutting portion  82  in the clockwise direction (counterclockwise in  FIG. 20 ) has the most protruding apex and meets the lid  5  first. 
     According to a fifth aspect of the invention, said teeth  50  have a substantially identical height and extend axially from an angular portion of the free edge of the punch  7  having an axial offset from one tooth  50  to the other. For this purpose, here, said free edge, in said cut-out portion  82 , is in the form of a ramp of increasing height in a clockwise direction (counterclockwise in  FIG. 20 ). Such an identical height of the teeth makes it possible to limit their risk of breakage compared to a configuration in which teeth of too small a size would be encountered. 
     As illustrated, said teeth  50  preferably have a substantially identical profile. This is, for example, a profile with a leading edge  52  extending substantially axially between said free edge  80  and each apex  51  and a return edge  53  extending at an angle between each apex  51  and said free edge  80 . Said peaks  51  are here formed at the junction of the leading edge  52 , the return edge  53 , an outer flank  54  of the tooth and an inclined surface  55  formed in the thickness of the teeth  50 . 
     In addition to the assembly shown in the preceding figures, said tube according to the invention comprises a skirt  102 , partially illustrated, connected to said tube head  3 .