Abstract:
The present invention relates to a device for applying runners ( 32 ) on closure profiles ( 22 ), comprising various actuator means ( 110, 120, 130, 140 ) driven by a common driving means ( 150 ), including a wheel ( 110 ) for driving a chain of runners ( 32 ) temporarily linked together by breakable bridges ( 34 ) in order to transfer successively each runner ( 32 ) towards an application station on the closure profiles ( 22 ); characterized in that the device includes means ( 170 ) for manually disengaging the driving wheel ( 110 ) relative to the other actuator members ( 120, 130, 140 ). The invention also relates to a method and a machine implementing the above-mentioned runner application device, and to the closure profiles and bags thus obtained.

Description:
This is a non-provisional application claiming the benefit of International application number PCT/EP2008/050159 filed Jan. 9, 2008. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention concerns the area of closure profiles for bags equipped with sliders. 
     Numerous closure profiles equipped with sliders have already been proposed. 
     One of the problems raised in this area relates to the engaging of the sliders on the profiles. 
     2. Description of Related Art 
     Document U.S. Pat. No. 6,490,769 gives an example of known sliders. The present invention applies in particular to use of the slider described in this document. However the invention is not limited to this particular slider. 
     Different devices have also been proposed intended to ensure the engaging of sliders on closure profiles. 
     Examples of known devices can be found in documents FR 2076345 and FR 2076728. 
     BRIEF SUMMARY OF THE INVENTION 
     The purpose of the present invention is to propose novel means designed to ensure the application of sliders onto a closure profile, having superior properties to those of the prior art. 
     This purpose is achieved under the invention by means of a device to apply sliders onto closure profiles, comprising different actuator elements driven by a common motor means including a driving wheel driving a chain of sliders provisionally joined together by scored links so as successively to transfer each slider towards a station where it is applied to the closure profile, characterized by the fact that the device comprises manual disengaging means for the driving wheel with respect to the other actuator elements. 
     The invention also relates to a method and machine using the abovementioned slider application device and to the closure profiles and bags equipped therewith. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Other characteristics, purposes and advantages of the present invention will become apparent on reading the following detailed description with reference to the appended drawings given as non-limiting examples in which: 
         FIG. 1  is a schematic perspective view of a machine to manufacture bags able to be equipped with a slider application device conforming to the invention, 
         FIGS. 2 and 3  are perspective views of the slider application device conforming to the present invention, 
         FIG. 4  is a partial cutaway side view of the slider application device conforming to the present invention, 
         FIG. 5  is a cross-sectional view of the device along the section plane referenced V-V in  FIG. 4 , and 
         FIGS. 6 and 7  are cross-sectional views of the same device along the section planes referenced VI-VI in  FIG. 5  and VII-VII in  FIG. 4 . 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The invention applies in particular to the manufacturing of bags on an automatic machine of form-fill-seal type schematically illustrated in appended  FIG. 1 . 
     Said machine  10  comprises:
         means  20  supplying a strip  22  of closure profiles,   means  30  supplying chains  32  of sliders,   a station  100  described in more detail below in the present invention intended to carry out sequential, individual application of each slider  32  onto the strip  22 ,   means  40  supplying a thermoplastic film  42 ,   a forming neck  50  associated with a filling chute  60  which conforms the film  42  from an initial planar state to a tube,   means  70  ensuring longitudinal welding of the adjacent longitudinal edges of the film  42  and fixing of the closure strip  22  equipped with sliders  32  onto the film  42 , and   transverse welding jaws  80  associated with cutting means  80  to separate the bags individually.       

     Said bag is schematically illustrated under reference  90  in  FIG. 1 . 
     The general structure of the machine illustrated  FIG. 1  is known to persons skilled in the art and will therefore not be described in further detail. 
     Also, appended  FIG. 1  shows a machine in which the closure strip  22  equipped with sliders  32  is applied longitudinally to the edges of the film  42  i.e. parallel to the direction of travel of the film  42 . As a variant the closure strip  22  equipped with sliders  32  can be applied crosswise onto the film  42  i.e. at least substantially perpendicular to the direction of travel of the film  42 . 
     According to other variants, the slider application device  100  conforming to the present invention can be used on any automatic packaging machine and on welding machines for the manufacturing of empty bags. 
     Additionally, according to the illustrated given  FIG. 1 , the slider application device  100  is designed to apply sliders  32  to the strip  22  of closure profiles before welding of the strip  22  onto the film. As a variant, however, the application device  100  according to the present invention can also be used to apply sliders  32  to the closure strip  22  after welding the closure strip  22  onto the film  42 , irrespective of the type of film conformation machine  42  that is used. 
     The application device  100  conforming to the present invention can also be used to pre-position sliders  32  on closure profile strips  22  at a fixed point, and to fix the closure strips thus equipped with sliders  32  onto a film during a subsequent, separate step and optionally on a different site. 
     The present invention applies to any type of closure strip  22  in particular closure strips comprising mating male and female profiles, hook profiles, profiles joined together by a U-shaped connection strip or equivalent to form an opening indicator, etc. . . . 
     The closure device  100 , conforming to the present invention and shown in the appended figures, comprises four actuator elements: a driving wheel  110 , a pusher  120 , a spacer  130  and a clamp  140 . These four actuator elements are driven by a common motor element  150  preferably consisting of a pneumatic jack  150  more precisely by a rod-and-valve assembly  152  joined to the jack piston  150  and driven on command in an alternate translation movement centered on axis A-A. 
     The general structure of these four actuator elements is known from the above-cited documents FR-A-2076728 and FR-A-2076345. It will therefore not be described in further detail in the remainder hereof. 
     It is recalled however:
         that the spacer  130  preferably comprises a fixed central insert  132  intended to be engaged between two profiles of the closure strip  22  for their separation, and two jaws  134 ,  136  surrounding the insert  132  and preferably driven alternately between a clamped position in which the jaws  134 ,  136  clamp support webs of the above-mentioned profiles against the outer surfaces of the insert  32  when the travel movement of the strips  22  is temporarily stopped for application of a slider  32 , and a drawn-apart position allowing travel of the closure strip  22 . The driving of the jaws  134 ,  136  between the two above-described positions by the motor  150  can have numerous configurations. Preferably, the jaws  134 ,  136  are drawn together by elastic means  131  and are drawn apart by a set of rollers  137  carried by the rod-and-valve assembly  152  and cooperating with cams  138  joined to the jaws  134 ,  136 .   that the clamp  140  positioned downstream of the spacer  130  relative to the direction of travel of the strip  22 , preferably comprises two jaws  144 ,  146 , driven alternately between a clamped position in which the jaws  144 ,  146  clamp the support webs of the above-mentioned profiles during temporary stoppage of the travel movement of the strips  22  for application of a slider  32 , and a drawn-apart position allowing travel movement of the closure strip  22 . The driving of the jaws  144 ,  146  between the two above-described positions by the motor  150  can also have numerous configurations. Preferably, the jaws  144 ,  146  are drawn together by elastic means  142  and are drawn apart by a set of rollers  147  carried by the rod-and-valve assembly  152  and cooperating with cams  148  joined to the jaws  144 ,  146 ,   that the driving wheel  110  is driven in rotation by means which will be detailed below, about an axis O-O parallel to the direction of travel of the strip  22 , to convey the sliders  32  joined together in a chain by scored links  34  successively towards an application station positioned between the spacer  130  and the clamp  140 ,   that the pusher  120  joined to the rod-and-valve assembly  152  is moved alternately in translation along axis A-A to push a slider  32 , placed opposite, onto the strip  22  (whose two profiles have been drawn apart upstream by the spacer  130 ) and to separate the slider  32  from the scored links  34  provisionally joining the sliders together (preferably by cutting these links  34  against an anvil provided at this station).       

     The chains of sliders  32  used preferably conform to those in document FR-A-2076728 with respect to their general structure. They will not therefore not be described in further detail in the remainder hereof. 
     However, preferably, each slider  32  in this chain conforms to document U.S. Pat. No. 6,490,769 in that at its top part it comprises two wings adapted to be acted upon by a tappet  122  (see  FIG. 7 ) provided at the end of the pusher  120  so as to draw apart the side walls of the slider before it is applied to the strip  22  as described in document U.S. Pat. No. 6,490,769. 
     The driving wheel  110  can have numerous configurations. On its periphery it comprises a series of teeth or bearers adapted successively to take in charge the sliders and to transfer them to the application station positioned between the spacer  130  and the clamp  140 . 
     The means to drive the wheel  110  in rotation by the rod-and-valve assembly  152  can be in the form of numerous embodiments. 
     In their general structure they preferably conform to the means defined in document FR-A-2076728. 
     More precisely, as can be seen in the appended figures, these means preferably comprise a lever  111  with two arms  112 ,  113  mounted in rotation about axis O-O. One of the arms  113  is connected to the rod-and-valve assembly  152  via a bar or connecting rod  114 . The second arm  112  carries a pawl  115  having angular clearance relative to the arm  112  and cooperating with a cogwheel  116  joined to the driving wheel  110 . 
     The pawl  115  can be associated with a return spring  117 . 
     As described in FR-A-2076728 in one direction of travel of the rod-and-valve assembly  152 , the pawl  115  drives wheel  116  and hence wheel  110  over an angular pitch. In the other direction of travel of the rod-and-valve assembly  152 , the pawl  115  pivots relative to the arm  112  to move away and reach the adjacent tooth of the cogwheel  115  before repeating a new driving operation of wheel  116 . 
     Wheel  110  and associated wheel  116  are braked by a friction brake  160  to prevent the wheel  110  from rotating in an opposite direction to that resulting from action of the lever  111  and pawl  115 . The friction brake according to the invention is formed of two friction washers or linings  162 ,  164  respectively arranged either side of the wheel  110 . More precisely, the two friction linings  162 ,  164  and the wheel  110  sandwiched therebetween are clamped between a frame of the device on one side and a disengageable actuator element  170  on the other side. 
     According to the embodiment shown in the appended figures, this element  170  is formed of a ring bearing upon the outer surface of the lining  164  and drawn into a clamping position by a set of tared springs  172 . 
     The ring  170  can however be drawn away from the wheel  110  so as to disengage the lining  164  and the wheel  110  by means of a system of screw/nut type. Numerous variants of embodiment thereof are possible. It will therefore not be described in further detail in the remainder hereof. 
     However, preferably, this screw/nut system comprises a threaded screw wheel  174  cooperating with a plate  176  carrying a set of tie rods  178  connected to the ring  170  (and on which the springs  172  for example are positioned) so that rotation of the screw wheel  174  via the plate  176  and the ties  178  ensures a pulling force on the ring  170  ensuring disengagement of the wheel  110 . 
     The general functioning of the device  100  conforming to the present invention remains identical to that known from and described in document FR-A-2076728 in particular. 
     However, the new possibility of disengaging the wheel  110  makes it possible, at the time of initial installation of a chain of sliders  32  or even during a maintenance operation, to disengage the wheel  110  with respect to the other actuator elements  120 ,  130 ,  140  and thereby ensure provisional free rotation of the wheel  110 , for example to engage or disengage a chain of sliders  32 . 
     Thereafter, the indispensable precise re-synchronization of the driving wheel  110  with the actuator elements  120 ,  130 ,  140  (this precise synchronization being mandatory since the sliders must be successively positioned with great precision relative to the pusher  120  during movement thereof) is ensured by simply placing the cogwheel  116  in abutment against the pawl  115  when tightening the screw wheel  174  to ensure engaging. 
     Evidently, the present invention is not limited to the particular embodiments just described but extends to any variant conforming to the spirit thereof.