Patent Publication Number: US-2012030919-A1

Title: Device and method for placing a slider on a bag with closure profiles

Description:
The present invention concerns the field of bags provided with mating closure profiles actuated by a slider. 
     It more particularly concerns a device and method for placing a slider on a bag with mating closure profiles. 
     French patent 07 59545, filed on 4 Dec. 2007 to the present applicant, describes a device and method for positioning a slider on a bag with closure profiles, this slider being provided with urging lugs projecting from its sidewalls, in the vicinity of the ends thereof opposite its base, in order provisionally to open the slider and facilitate its engaging onto the closure profiles when demand is placed on the lugs. 
     This technique generally gives satisfaction. 
     However, the vast majority of sliders available on the market are devoid of such lugs, which means that the solution described in this patent application cannot be applied thereto. 
     In addition, a device for positioning sliders is known from document U.S. Pat. No. 6,161,271 which makes use of a carousel. A slider is placed in housing and a pin acts on the base thereof so that it is ejected. The edges of the slider come into contact with abutments of triangular shape slidingly mounted along diverging guide walls. As the slider moves, its wings push the abutments which force the free ends of the bag to come together. 
     The present invention sets out to remedy the shortcoming set forth above by proposing a device and method which allow the positioning of a slider on a bag with closure profiles, this slider being devoid of said projecting urging lugs, without having recourse to a carousel whose structure and functioning by definition are complicated. 
     Therefore, according to a first aspect, the present invention relates to a device for mounting a slider to actuate closure profiles, in particular for a closure assembly fitted to a bag, which comprises a base, two sidewalls or flanges and means adapted respectively to urge said closure profiles to draw together or to draw away from each other depending upon the direction of travel of the slider along the profiles, so as to move the profiles between an engaged closed position and a separated open position, on a bag with mating closure profiles or on an assembly of mating closure profiles, this device comprising at least one clamp to hold the profiles in stable position and means for pushing the slider towards means for provisionally drawing apart said flanges of the slider with a view to causing it to cooperate with said profiles in stable position, these drawing-apart means comprising cam paths with rising slope. 
     According to the invention, said means are composed of retractable cams which, in a first non-retracted position, interact with said slider so that during its travel the inner face of its flanges comes into contact with the cam paths so as gradually to draw them apart, and which in a second retracted position no longer interact with said slider so that said flanges are drawn close to one another, 
     the changeover from the first to the second position taking place by contact of the base of said slider with said cams, during the travel of the said slider. 
     From the foregoing, it will be understood that the changeover from the first to the second position of the cams occurs simply during the movement of the slider when its base comes into contact with said cams. 
     It is therefore the sliding or relative movement of the slider relative to the cams which causes retraction thereof. 
     According to other advantageous, non-limiting characteristics of this device:
         the said cams are cams with pivoting axis, the changeover from the first to the second position occurring by pivoting around this axis;   the said axis extends over a plane generally parallel to the plane in which the base of said slider is contained;   it comprises means for retaining said cams in said first position, holding them in this position for as long as the base of the slider is not contact therewith;       

     the said retaining means are composed of springs;
         the said cams have one bevelled face, the changeover from the first to the second position taking place by wedge effect when said base of the slider comes into contact with this bevelled face;   it comprises two pairs of cams, each pair being positioned to come into contact with one same flange of said slider;   said pairs are separated by a positioning gap for said profiles;   it comprises at least one abutment for immobilising the said profiles,   it comprises a pair of abutments, each being positioned so that it comes into contact with one side of said profiles;   said abutments are each joined to a jaw of said clamp;   said abutment is retractable and is adapted so that it can be moved to a retracted position in which it no longer immobilises the said profiles when said slider is in position thereupon.       

     Another aspect of the invention concerns a method for placing a slider on a bag with mating closure profiles, this slider comprising a base, two flanges and means adapted respectively to urge said closure profiles to draw together or to draw away from each other depending upon the direction of travel of the slider along the profiles, to move said profiles between an engaged closed position and a separated open position, by means of clamps, a method which comprises the steps of: 
     a) opening the jaws of each clamp and engaging therein the edge of the bag provided with mating profiles; 
     b) clamping the jaws to immobilise the bag; 
     c) pushing said slider in the direction of the bag so that the flanges thereof are gradually drawn apart in order to engage the slider on the profiles, then gradually drawing together the flanges to lock the slider on the said profiles. 
     According to the invention, this method is noteworthy in the fact that at step c):
         the flanges of said slider are gradually drawn apart by means of retractable cams which, in a first non-retracted position, interact with the said slider so that as it moves the inner face of its flanges comes into contact with the cam paths with rising slope carried by these cams so as gradually to draw them away from each other;   the flanges are then drawn towards each other by moving said cams to a second retracted position in which the inner face of the flanges is no longer in contact with the cam paths with rising slope;   the changeover from the first to the second position taking place by contact of the base of the said slider with the said cams during the movement of the said slider.       

     According to one particular embodiment of this method, cams with pivot axis are used, the changeover from the first to the second position occurring by pivoting around this axis. 
     Advantageously, the cams used have one bevelled face, the changeover from the first to the second position taking place by wedge effect when the said base of the slider comes into contact with this bevelled face. 
     Other characteristics and advantages of the present invention will become apparent on reading the following detailed description of a preferred embodiment. 
    
    
     
       This description is made with reference to the appended drawings in which: 
         FIG. 1  is a partial, simplified view along a longitudinal and vertical median sectional plane of a device conforming to the invention; 
         FIGS. 2A to 7A  are partial views of the device in  FIG. 1 , intended to illustrate different steps of the method according to the invention, 
         FIGS. 2B to 7B  are magnified views of the corresponding regions in  FIGS. 2A to 7A , identified by a circle; 
         FIGS. 2C to 7C  are similar views to  FIGS. 2A to 7A  as cut by the plane indicated in these latter figures; 
         FIGS. 2D to 7D  are magnified views of the corresponding regions in  FIGS. 2C to 7C , identified by a circle; 
         FIGS. 9A and 9B  are perspective views of a cam of the above-mentioned device; 
         FIGS. 9C and 9D  are side and overhead views of this cam; 
         FIGS. 10A to 14A  are simplified side views of a slider and associated cams, in different positions illustrating the main steps of the method; 
         FIGS. 10B to 14B  are similar to  FIGS. 10A to 14A , the sliders and cams being shown this time from overhead. 
     
    
    
     The device for placing a slider, such as chiefly illustrated  FIG. 1  and in the other appended figures, is a device of generally known type for mounting a slider on bags with mating closure profiles. 
     For example the general structure of said device is described in document FR-A-2076728. 
     In the example of embodiment described herein, the device illustrates the positioning of a slider  1  on a bag S provided with mating profiles P 1 , P 2 . 
     As illustrated in  FIG. 1 , each profile P 1 , P 2  of generally known structure is carried by a strip  4  (or is an integral part of said strip). These two strips are both respectively attached to the inner face of two films  2  and  3  forming the large sides of the bag  3  to be equipped. 
     This description evidently applies also to the positioning of a slider on profiles P 1 , P 2  not yet associated with a bag. In said hypothesis, the attaching of the profiles to the bags is conducted at a later stage. 
     The bag is part of a continuous web of bags (not illustrated) which is moved step-by-step so that each in turn is equipped with a slider. The direction of travel of this web of adjacent bags is illustrated by the arrow f in  FIG. 1 . 
     In manner known per se, the device  6  comprises a pair of clamps  7  having parallel movement, the upper jaw thereof being referenced  70  whilst the lower jaw is referenced  71 . 
     Each jaw, to some extent, is composed of two parallel semi-jaws joined to each other. 
     Therefore if reference is made to  FIG. 2C , it is ascertained that the upper jaw  70  is formed of two semi-jaws  700  which are the image of each other relative to a longitudinal axis Y-Y′ perpendicular to the travel axis of the bag S. 
     The same applies to the lower jaw  71  which is the reverse image of jaw  70 . 
     The two semi-jaws of each jaw are separated from each other by a channel C identified in  FIG. 2C  having an axis Y-Y′. 
     In manner known per se, this device comprises means, not illustrated, for the feeding of sliders  1 . These sliders may be bulk packed and distributed by a vibrating feeder with loading magazine, or they may be arranged in a line one after the other. 
     Evidently, and in accordance with the known state of the art as described in the above-cited document for example, said device comprises slider feed means whose functioning is controlled by the functioning of its other constituent members and in particular by those which allow the mounting of said slider on the profiles. 
     As can be seen in particular in  FIG. 1 , the device is provided with a double-acting cylinder  61  in which the free end of the rod carries a piston  60  or linear actuator. 
     This piston is capable of sliding in predetermined travel sequences inside the above-mentioned channel C, along the axis Y-Y′. Ahead of this piston there is a space, not illustrated, for receiving a new slider  1  to be placed in position. 
     The back and forward movements of the piston are referenced by arrows g and h in  FIG. 1 . 
     With particular reference to  FIG. 2C , it can be seen that the two semi-jaws  700  of the upper jaw  70  (and similarly for the lower jaw  71 ) comprise a cavity  701  arranged transversally whose opening opens opposite the second semi-jaw. 
     Inside each cavity  701  there is arranged a retractable cam  5  whose structure and function is explained below. 
     Still with reference to this figure, it can be seen that the space between the two semi-jaws  700 , to within clearance, is very slightly larger than the length of the slider  1  to be placed in position. 
     It will also be ascertained that the free ends of the two upper semi-jaws  700  (and of the two lower semi-jaws) are connected by an abutment  72  which comprises a nose  720  extending inside the aforementioned channel C. 
     This is a retractable abutment, this abutment being slidingly mounted on rods  721  on which helical springs  722  are press-fitted. These springs tend to return the abutment  720  to its position illustrated  FIG. 2C  in which the nose  720  is engaged inside the channel C. 
     Reference will now be made to  FIGS. 9A to 9D  to describe the aforementioned retractable cams. 
     As indicated above, each semi-jaw is equipped with a cam  5 . They are all identical and mounted so that they are the mirror image of each other. 
     Therefore a description of only one thereof will be given, this description applying to the others. 
     The cam  5  under consideration can be seen in perspective in  FIG. 9A . 
     It comprises an upper body  51 , a lower body  53  and an intermediate portion  52 . 
     The upper body  51  lies substantially within a rectangular parallelepiped whose upper and lower faces are referenced  512  and  513 . 
     Its large side faces  511  extend longitudinally i.e. parallel to the aforementioned axis Y-Y′ when the cam is in the first non-retracted position. 
     A cylindrical through-hole  510  provides communication between the upper face  512  and lower face  513  of the cam. 
     The axis of this orifice is referenced X-X′. A rotating shaft is press-fitted therein so that it is possible to cause the cam to undergo a rotational movement relative to this axis. 
     The upper body  51  is continued on the side of its lower face  513  by an intermediate portion  52  which imparts a stepped profile thereto. 
     This intermediate portion connects to a lower body  53  which partly extends in the continuation of the upper body. 
     This lower body comprises two longitudinal faces  530  whose mutual separating distance is greater than the distance between the faces  511  of the upper body. 
     It will be noted however that one of the faces  530  extends over the same plane as the face  511  arranged on the same side. 
     On the opposite side, the lower body therefore projects laterally to form on its upper face a rising slope cam path  50 , this rising slope originating on the side of the upper body  51  in the direction of the free end of the lower body  53 . 
     Also, it can be seen that the longitudinal face  530  which borders the aforementioned cam path  50  connects to the intermediate portion  52  via a bevelled portion  531  whose function is explained below. 
     The aforementioned face  530  connects to the bevelled portion  531  via a lug  532 . 
     These cams  5  are mounted in the device so that the lower body  53  is engaged in the aforementioned cavities  701 . 
     Helical springs  5 ′ are mounted in these cavities and bear upon the face  530  opposite the cam path  50 , tending to place demand thereupon so that the body  53  projects from the cavity  701 . 
     More precisely, the cam paths  50  and the bevelled portion  531 , as shown  FIG. 2C , extend inside the channel C when the cams  5  take up their first non-retracted position. 
     Evidently, the cavity  701  is conformed also to receive the upper body  51  and its associated pivot axis. 
     With reference to  FIGS. 2A to 8D  and also to  FIGS. 10A to 14B , a description will now be given of the manner in which a slider is placed on the mating profiles P 1 , P 2  such as those illustrated  FIG. 1 . 
     The slider concerned is particularly visible in  FIG. 2B . 
     It is a slider  1  in plastic of usual type which comprises a base  10  and two parallel flanges  11  and  12  and means  13  which extend parallel to the flanges  11  and  12  from the base  10  and which are adapted to urge the closure profiles P 1 , P 2  respectively to draw together or to draw apart depending on the direction of travel of the slider along these profiles. 
     In manner known per se, the flanges  11  and  12  have sufficient elasticity so that they can be drawn apart to allow the profiles P 1 , P 2  to be positioned inside corridors which are delimited by the means  13  and the two flanges  11  and  12 . 
     The method of the invention comprises the following steps. 
     At a preliminary step which corresponds to  FIGS. 2A to 2D  and to  FIGS. 10A and 10D , the jaws  70  and  71  of the clamp  7  are drawn away from each other in open position. 
     Mechanized means, conveying a web of bags to be equipped with sliders, position one bag and immobilise it level with said clamp as shown  FIG. 2A . At the same time, a slider  1  is brought inside the device, inside the channel C by means not illustrated. 
     At the next step, illustrated  FIGS. 3A to 3D  and  11 A and  11 B, the jaws  70  and  71  are closed over the profiles P 1 , P 2 . 
     The mobile abutments  72  are arranged so as to clamp these profiles tightly against each other and, being constantly urged by the springs with which they are equipped, they oppose any undue movement thereof in the direction of the arrow g, i.e. in a direction which would distance them away from the slider  1 . 
     The piston or linear actuator  60  of the cylinder is then gradually moved in the direction of the arrow g so that it comes to bear against the base  10  of the slider to push it in the direction of the profiles P 1  and P 2 . 
     During this movement, the adequately arranged cams  5  gradually enter inside the slider  1  so that the cam paths  50  come into contact with the inner faces of the flanges  11  and  12  of the slider. 
     It will therefore be understood that as and when this movement takes place, the flanges  11  and  12  will draw away from each other so as to release sufficient space between themselves and the means  13  to allow the engaging of the profiles P 1 , P 2 . 
     After a certain travel distance, which corresponds to the step which can be seen  FIGS. 4A to 4D  and in  FIGS. 12A and 12B , the hooks of the profiles P 1 , P 2  come to abut inside corridors delimited by the flanges  11  and  12 , and the means  13 . 
     In addition, the base  10  of the slider comes into contact with the retractable cams  5 . 
     This contact is made at the bevelled face  531  which, by wedge effect, causes rotation of the cams around the axis X-X′ so that they gradually move inside the cavities  701 . 
     At this step, the cams  5  are still partly engaged in the slider with the result that the slider flanges continue to be drawn apart. 
     At a following step which corresponds to  FIGS. 5A to 5D  and  13 A and  13 B, the piston  60  continues to cause the slider  1  to move forward. 
     Under the effect of this forward movement, the mobile abutments  72  move back against the springs with which they are equipped, whilst maintaining a counter-pressure on the profiles which contributes towards the insertion of the end of these profiles inside the slider. 
     Under the action of the movement of the base of the slider, the cams  5  continue their rotation so that they remain inside the slider  1  whose flanges continue to draw away from each other. 
     At a subsequent step illustrated  FIGS. 6A to 6D  and  14 A and  14 B, the piston  60  is in maximum forward position and therefore has continued to move the slider in the direction of the arrow g. 
     Under the action of the base  10  of the slider, the cams  5  continue their rotation against the springs  5 ′ and when the base  10  of the slider has reached the lugs  532  of the cams  5 , the cams retract fully inside the cavities  701  so that they move out of the slider  1 , the result being that the flanges  11  and  12  close over the profiles P 1 , P 2 . 
     At the following step, illustrated  FIGS. 7A to 7D , the piston  60  is guided so that it moves back in the direction of arrow h under the effect of the force exerted on the profiles P 1 , P 2  by the mobile abutments  72 . The slider  1 , press-fitted onto the profiles P 1 , P 2 , also moves backwards. 
     The side faces of the cams  5  are then in contact with the outer side faces of the slider  1  so that only the lugs  532  are slightly inserted inside the slider. 
     At the following step illustrated  FIGS. 8A to 8D , the jaws  70  and  71  of the clamp open to release the web of bags of which one bag has just been equipped with a slider. 
     At the time of opening of these jaws, and by means of the inclined face of the cams  5 , these cams are drawn slightly aside on account of their axis of rotation and move fully outside the slider without opening it. 
     It is therefore possible to allow the web of bags to move forward by one pitch for the mounting of a new slider.