Abstract:
The present invention relates to a closing device for sachets comprising at least two complementary closing elements ( 200, 300 ) and an associated slider ( 100 ) comprising a central bead ( 140 ), adapted for modifying the joining state of said two elements ( 200, 300 ) so as to respectively separate or engage the latter according to its direction of motion, characterized in that the slider ( 100 ) comprises at least one flexible lip ( 145, 146 ) placed on the apex of the central bead ( 140 ) opposite a lead angle ( 216, 316 ) provided on the closing element ( 200, 300 ), according to a configuration such that any attempt to pull back the slider results in autolocking hanging of the lip ( 145, 146 ).

Description:
TECHNICAL FIELD 
     The present invention relates to the field of reclosable sachets comprising at their outlet closing devices known for allowing successive multi-openings/closures, as required. 
     More precisely, the present invention relates to closing devices actuated via a slider. 
     BACKGROUND 
     Numerous closing devices for sachets have already been put forward. 
     The majority of these devices is formed on the basis of complementary male/female profiles, or even hooks or hook and loop fastener-type devices such as those sold under the trademark VELCRO. 
     Numerous slider structures for controlling such closing devices have also been proposed. 
     The aim of the present invention is to propose novel closing devices with a slider having properties superior to those of known devices. 
     More precisely, the aim of the present invention is to propose means limiting the risk of the sliders being torn off. 
     Different attempts have been made for this purpose. However, none of them provides total satisfaction. 
     The documents US 2005/041892, EP 1153552, EP 1447338 and U.S. Pat. No. 3,426,396 for example describe rigid structures on sliders, intended to be rest on complementary elements provided on the closing devices. 
     The documents U.S. Pat. No. 6,611,998 and U.S. Pat. No. 6,691,375 describe a solution consisting of placing, on the inner surfaces of the lateral flanges of the sliders flexible lips intended to cooperate with complementary elements provided on the closing devices. The drawback to this solution is forcing the lateral flanges apart when the closing devices stress said flexible lips. 
     The above aim is achieved within the framework of the present invention due to a closing device for a sachet comprising at least two complementary closing elements and an associated slider comprising a central bead, adapted to modify the joining state of said two elements by respectively separating or engaging the latter according to its direction of motion, characterized in that the slider comprises at least one flexible lip placed on the apex of the central bead opposite a lead angle provided on a closing element, according to a configuration such that any attempt to withdraw the slider results in autolocking hanging of the lip. 
     “Autolocking hanging” of the lip is understood to mean any reinforcing of the effort exerted on the flexible lip by the lead angle opposite the closing element, tending to reinforce locking of said flexible lip against said lead angle. 
     As will also be understood within the scope of the present invention since the flexible lip is carried by the apex of the central bead of the slider and not by a lateral flange of the latter, the thrust exerted on the flexible lip is distributed over the central bead and not on the lateral flanges of the slider. 
     The present invention also concerns sachets equipped with such a closing device. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Other characteristics, aims and advantages of the present invention will emerge from the following detailed description, and by means of the attached diagrams, given by way of non-limiting examples and in which: 
         FIG. 1  illustrates a transversal sectional view of a closing device according to the present invention according to a first cutting plane of the slider passing through two separate channels maintaining closure profiles in the separated position, 
         FIG. 2  illustrates a sectional view of the same device according to a second cutting plane parallel to that of  FIG. 1 , at the level of which the two channels are joined to enable the closing profiles to be engaged, 
         FIG. 3  illustrates a view similar to  FIG. 1  simulating an attempt to pull back the slider, 
         FIG. 4  illustrates a sectional view similar to a second embodiment of the closing device according to the present invention, and 
         FIGS. 5 ,  6 ,  7  and  8  illustrate views similar to  FIG. 1  in transversal section of four other variant embodiments of closing devices according to the present invention. 
     
    
    
     DETAILED DESCRIPTION 
     A slider  100  of general classical structure is evident in  FIG. 1 . 
     This slider  100  comprises a base  110 , two lateral flanges  10 ,  120 ,  130  and a central bead  140 . 
     The lateral flanges  120 ,  130  and the central bead  140  define in combination two channels  150 ,  160 , in part at least not parallel. These channels  150 ,  160  join at one end of the slider  100 , as in  FIG. 2 . The channels  150 ,  160  join together the closing elements  200 ,  300 , respectively. The specialist understands that as it is moved the slider  100 , according to the direction of motion, separates the closing profiles  200 ,  300 , as shown in  FIG. 1 , or on the contrary carries the latter engaged, as shown in  FIG. 2 . 
     The attached figures illustrate two closing elements  200 ,  300  extruded onto films  250 ,  350 , constituting the sachet proper. As a variant, and in a manner known per se, the closing elements  200 ,  300  could be made initially separately, then connected and fixed onto the films  250 ,  350  by any appropriate means, for example by thermal welding. 
     According to the embodiments illustrated in the attached figures, the two closing elements  200 ,  300  comprise support bulges  210 ,  310 , each of which carries a closing element as such  212 ,  312  respectively of complementary male and female type. By way of variant, such elements  212 ,  312  could be replaced by any equivalent means, for example structures with hooks or complementary hook and loop fastener type such as those sold under the trademark VELCRO. 
     As mentioned earlier, according to the present invention the slider  100  comprises, on the apex of the slider  100  opposite the base  110 , at least one flexible lip  145 ,  146  placed opposite a lead angle  216 ,  316  provided on a closing element  200 ,  300 , according to a configuration, such that any attempt to pull back the slider  100  results in autolocking hanging of the lip  145 ,  146 . More precisely again, preferably within the scope of the present invention, the closing device comprises two lips  145 ,  146  cooperating respectively with a lead angle  216 ,  316  provided on each of the two elements  200 ,  300 . 
     The lead angles  216 ,  316  are provided on the inner face of the closing elements  200 ,  300 . The lips  145 ,  146  are oriented towards the base  110  by moving away from a plane of symmetry 0-0 parallel to the direction of translation of the slider and passing through the plane of symmetry of the central bead  140 . 
       FIG. 3  shows that if the attempt is made to pull back the slider  100 , the lead angles  216 ,  316  stress the lips  145 ,  146 . The lips  145 ,  146  then are underpinned and deformed, their apex being brought closer to the lateral flanges  120 ,  130  (moving away from the base  110  by deformation accompanied by a pivoting movement about the zone connecting the lips  145 ,  146  at the apex of the central bead  140 ). This ends in autolocking, where the closing elements or the films  250 ,  350  are wedged between the apex of the lips  145 ,  146  and the flanges  120 ,  130 . The specialist will understand that simultaneously this produces a seal between the two film elements  250 ,  350  inside the slider  100 . 
     The height of the lips  145 ,  146 , illustrated under reference e 1  in  FIG. 3 , is preferably greater than a width e 2 , illustrated in the same  FIG. 3 , of the free opening formed between the apex of the central bead  140  and the free end of the flanges  120 ,  130 . Consequently, owing to this arrangement, it is guaranteed that during an attempt to pull back the slider  100  the apex of the lips  145 ,  146  rests against the films  250 ,  350 . 
     In the case as shown in  FIGS. 1 to 3 , the lateral flanges  120 ,  130  have a flared sole plate  121 ,  131  at their free end, more precisely, the lips  145 ,  146  are stressed against the flanks of these sole plates  121 ,  131  during an attempt to pull back the slider  100 . 
       FIG. 4  illustrates a variant embodiment according to which the lips  145 ,  146  have a length even greater, such that their apexes do not rest against the flanks of the sole plates  121 ,  131  but against lead angles  123 ,  133  formed between the flanks of the sole plates  121 ,  131  and the flanges  120 ,  130 , and directed towards the base  110 . The specialist will understand that this arrangement further reinforces the locking effect on the underpinned lips  145 ,  146 , at the same time limiting the stress by separating the lateral flanges  120 ,  130 . 
       FIG. 5  shows another variant embodiment according to which it is provided with lips  125 ,  135 ,  145 ,  146  simultaneously on the lateral flanges  120 ,  130  and on the central bead  140 . These lips  125 ,  135  and  145 ,  146  cooperate with lead angles  215 ,  315 ,  216 ,  316  provided respectively on the outer faces and on the inner faces  20  of the bulges  210 ,  310  of the closing elements. 
     According to the embodiment shown in  FIG. 5 , the lips above  125 ,  135  and  145 ,  146  are situated substantially on the same level and have substantially identical lengths and suppleness. So their apexes come into mutual contact on either side of the films  250 ,  350  when the slider  100  is stressed or pulled back. 
     On the contrary  FIGS. 6 and 7  show pairs of lips  125 ,  135  and  145 ,  146 , respectively, having different lengths. 
     According to the embodiment shown in  FIG. 6 , the longest lips  145 ,  146  are solid with the central bead  140 . 
     Conversely, according to the embodiment shown in  FIG. 7 , the longest lips  125 ,  135  are solid with the inner faces of the lateral flanges  120 ,  130   
     In the two cases of the embodiments illustrated in  FIGS. 6 and 7 , the longest lips are placed on the interior of the slider relative to the shortest lips. 
     The specialist will understand that in this case, the outer face of the longest lips comes into contact with the apex of the shortest lips during an attempt to pull back the slider. 
       FIG. 8  shows another variant embodiment according to which the lateral flanges  120 ,  130  are fitted, in the vicinity of their free end opposite the base  110 , and on their inner face, with substantially rigid flanges  122 ,  132 . These flanges  122 ,  132  each define an inclined facet  124 ,  134  forming a ramp which converges towards the plane symmetry 0-0 by moving away from the base  110 . Two lips  145 ,  146  solid with the end free of the central bead  140  opposite the base  110  are placed on the interior of these ramps  124 ,  134 . The lips  144 ,  146  converge towards the base  100  by moving away from the plane of symmetry 0-0. 
     The ramps  124 ,  134  define in combination with the lips  145 ,  146  channels  128 ,  138  which converge by moving away from the base  110 . 
     The specialist will comprehend from studying  FIG. 8  that the channels  128 ,  138  cause the films  250 ,  350  to approach one another and ensure contact between the latter at the level of a zone referenced  290  in  FIG. 8 . Such a structure obviously improves the sealing property of the device. 
     In addition, the specialist will comprehend that this sealing is further reinforced when an attempt is made to pull back the slider, with the lips  145 ,  146   30  tending to accentuate the effort and convergence of the films  250 ,  350 . 
     Scrutiny of the attached figures will clarify that the slider  100  is preferably fitted on the outer face of the base  110  with two tappets or lugs  112 ,  114  substantially adjacent to the flanges  120 ,  130 . In a manner known per se, such tappets  112 ,  114 , when they are caused to approach one another, stress the flanges  120 ,  130  to move apart and consequently accentuate the width of opening of the channels  150 ,  160  to facilitate engagement of a slider on the closing elements  210 ,  220 . 
     The lips  125 ,  135 ,  145 ,  146  can be made from the same material as the essential material of the slider  100 , or from a different material. They are preferably made from a supple material such as polyethylene or ethylene copolymer. 
     It is understood that the present invention is not limited to the particular embodiments described hereinabove but extends to any variant in keeping with its basic idea.