Abstract:
A device for separation of folders within a layer of folders includes elements for blocking the advance of a folder in the layer, elements for unlayering the folders preceding the retained folder, and elements for retaining the blocked folder and the folders following it relative to the advance of the layer acting successively on the folders.

Description:
BACKGROUND OF THE INVENTION 
   The present invention relates to a separating device to form a bundle of stacked folders, by offsetting the folders in a layer of advancing folders. 
   During stacking of the folders, there are formed bundles of stacked folders to package them for transport. To form these bundles, it is necessary to carry out a separation between two folders in the formed stack. 
   DESCRIPTION OF THE RELATED ART 
   To produce this separation between two folders, there have previously been proposed many and varied devices. Thus, there are known separators acting within the bundle undergoing formation, and others causing an interruption in the layer. 
   Thus, there is known a separator acting directly in the bundle without interruption of the layer, as described in the patent EP 0 739 843 of the applicant and in the patent EP 0 872 443. Such a separator is introduced into the stack of folders either from below the bundle, a hook introduced between two folders retaining one of the folders against the direction of advance creating a space for the introduction of the separator, or at the point of stacking, a tab being disposed between two folders and then spacing the folders to let the separator pass. 
   These separators acting within the stack of folders without interruption of the layer are not suitable for all the forms of folders, in particular deep and wide forms. Moreover, they have the tendency systematically to raise the folders for certain productions during the introduction of the separator into the bundle, even when the system uses devices for pre-introduction into the layer such as tabs. 
   For separators with interruption of the layer, there has been proposed a separator comprising a hook which acts within the layer of folders by retaining one folder relative to the adjacent folder as well as a separator with movement by a jack which also permits providing a separation. 
   However, such systems have drawbacks. In particular, these systems are not adapted for stacking devices in which the speed of the layer of folders and the flow of the folders are rapid. 
   Thus, the precision of interruption created within the layer by the separators is insufficient to be able to obtain a suitable synchronization with the movement of the bundle to be terminated, located upstream of the device. Moreover, there generally occurs too great an accumulation of folders among the folders which follow the interruption and the time of interruption that is needed is too long to be able to compensate the imprecision and to guarantee that the interruption is fairly long. 
   Moreover, the interruption caused by these separators is always greater than the interruption or the simple offset of a single folder relative to the following one so as then to introduce downstream into the bundle undergoing formation a separation member. This greater interruption permits guaranteeing the reliability of execution. 
   However, when the separator of this type operates, the folders which follow the interruption of the layer accumulate against the stop member of the layer, which gives rise to a phenomenon of inversion of the interval of the layer having as a result a disturbance of the stacking of the first folders on the downstream stacking device. 
   SUMMARY OF THE INVENTION 
   The present invention thus has for its object to overcome these drawbacks by providing a device for separating folders in the layer which permits an offset of one folder relative to another which will be equivalent to the precise height of the separation member located downstream. 
   To this end, the invention has for its object a device for the separation of folders within a layer of folders, characterized in that it comprises means for blocking one folder in the layer, means for unlayering folders preceding the blocked folder, and means for holding the blocked folder and the folders following it relative to the advance of the layer acting successively on said folders. 
   Thus preferably there is obtained a simple offset of the folders without disordering them, the holding means for the folders permitting opposing itself to their advance progressively, which permits controlling the accumulation of the folders. In this way, there is desirably reduced the interval of the layer, the blocked folders “recoiling” relative to the advance of the layer. 
   Thus, the layer of folders continues to advance and the progressive blocking of the folders after blocking permits reducing the interval of the layer in a controlled manner instead of letting the folders accumulate in a disordered manner behind the blocked folder. 
   Preferably, the blocking means and the unlayering means are positioned, relative to the direction of advance of the layer, downstream of the retention means. Preferably, the blocking means face the advance of the layer when they act. Thus, these blocking means, which have a pivotal axis permitting driving a blocking member between an inactive position above the layer and an active blocking position within the layer of folders, are positioned such that the pivotal axis is downstream of the point of blocking in the layer. In this way, there is desirably avoided the drawbacks connected with an upstream position of the pivotal axis relative to the blocking point. Thus, if there is carried out a stoppage in the layer with the pivotal axis located upstream, the separation is less reliable and can let a further folder escape, disturbing the precision of the separation. 
   This action of the blocking means, facing the layer, guarantees that no folder can jump over the blocking means. 
   According to one embodiment, the retained means are constituted by at least one lever mounted pivotally under the influence of a drive means such as a jack, relative to a support movable on a fixed frame and drivable with movement in a direction opposite the direction of advance of the layer of folders, a fixed belt being would about the lever and the support such that upon recoil of the lever and the support, the fixed belt unrolls and, being in contact with the folders of the layer, gives rise according to its unrolling, to the successive stopping of said folders interfingering between said belt and the path of the layer, thereby reducing the interval of said folders. 
   The speed of driving the movement of the support of the retaining means, also called the speed of the retained means, is proportional to the speed of advance and permits defining the interval between the folders. 
   Preferably, the speed of the retaining means is a speed proportional to the speed of advance, the ratio of the proportion being fixed no matter what the speed of the layer. For this reason, the device guarantees a synchronism of the speed of the retaining means relative to the speed of advance. 
   Thus, generally speaking, the new interval of the layer P′ resulting from the separation, can be defined by the following equation: 
   
     
       
         
           
             P 
             ′ 
           
           = 
           
             P 
             × 
             
               Vr 
               
                 Vr 
                 × 
                 Va 
               
             
           
         
       
     
   
   In which P is the interval of the layer, Vr the speed of the retaining means and Va the speed of advance of the layer of folders. 
   Thus, if the retaining means for the folders has a speed equal to the speed of advance of the layer, the interval of the layer will be reduced to half during separation. 
   In all the cases to permit a separation member of a height H to pass between the separated folders without tearing or carrying away a folder which has not arrived below, it is necessary that the separation device for the layer carries out an offset between the two upper folders at the height of the separation member to be introduced. 
   According to another embodiment, the retention means can be constituted by a series of shafts located below the layer of folders, driven independently from each other, constituting for example a portion of the conveyor of the layer of folders, said shafts being driven at a speed identical to the speed of the layer and the first shaft of the series being positioned substantially facing the blocking means for a folder such that, when said blocking means act, the first shaft is thus stopped, then the second, then the third and so on, all the folders stopping one after the other at an equal distance from the preceding one. 
   Thus the new interval of the layer P′ satisfies the following formula: 
   
     
       
         
           
             P 
             ′ 
           
           = 
           
             P 
             × 
             
               Vr 
               
                 Vr 
                 × 
                 Va 
               
             
           
         
       
     
   
   P being the interval of the layer of folders, Va the speed of the layer of folders and Vr being the speed of propagation of the stopping of the shafts in the direction of recoil, which is to say Vr=Da/T, Da being the distance between the axes of the two shafts and T the time between the stopping of one shaft and the stopping of the immediately following shaft. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention will now be described in greater detail with reference to the drawing, in which: 
       FIG. 1  is a schematic side view of a separation device according to the invention positioned above a layer of folders in the inactive position; 
       FIG. 2  shows the device according to  FIG. 1  in the position just before separation; 
       FIG. 3  shows the device of  FIG. 1  in the blocking position of the folder; 
       FIG. 4  shows the device of  FIG. 1  in the position of recoil relative to the folders; 
       FIG. 5  shows the device of  FIG. 1  after separation. 
   

   DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   The device  1  is mounted above a horizontal conveyor on which circulates a layer  2  of folders C. 
   The device according to the invention is constituted by a fixed frame  3  adapted to be mounted above the path of a layer  2  of folders. 
   The blocking means, the unlayering means and the retention means are mounted pivotally on the frame  3  so as to be driven with pivotal movement between 1) an inactive position in which they are disposed substantially in the plane of the fixed frame  3  ( FIG. 1 ) and 2) an active separation position in which they are lowered into contact with the layer  2  of folders ( FIGS. 2 ,  3  and  4 ). 
   The unlayering means are positioned, relative to the direction of advance of the layer  2  shown by the arrow A, downstream of the blocking means on a same support  4  mounted pivotally relative to the fixed frame  3 , under the action of a drive means for pivoting them, such as a jack. 
   These unlayering and blocking means are themselves disposed, relative to the direction of advance of the layer  2 , downstream of the retention means, carried by a second support  5 . 
   The blocking means are constituted of at least one blocking finger  6  pivotally mounted on the support  4  about an axis perpendicular to the direction of advance of the layer  2 , at the upstream end of said support  4 . 
   The blocking finger  6  is held in inactive position by a return means for example a resilient element, such as a spring or a motorized means and is brought to the active position under the influence of a drive means such as a jack. The pivotal axis of the blocking finger  6  being located downstream of the point of blockage in the layer  2 , the blocking finger  6  acts because of this on the surface of the layer  2 . 
   The unlayering means are constituted by at least one belt  7  driven between a wheel  8  mounted on the support  4 , opposite the blocking finger  6 , and a wheel  9  of larger diameter positioned adjacent the blocking finger  6 , downstream of this latter in the direction of advance of the folders. 
   A roller  10  whose axis of rotation is close to or coincident with the pivotal axis of the blocking finger  6 , also forms a portion of said unlayering means. Preferably, a roller R is positioned facing the unlayering wheel  9  below the layer  2  of folders. 
   Preferably, the conveyor for the layer  2  of folders comprises idle rollers below the blocking fingers  6  and the unlayering wheels  8 ,  9 , these idle rollers being driven by friction of the belt of the conveyor at the same speed as the latter and stopping when the blocking fingers  6  bear against the blocked folder but not preventing the previous folder from being extracted by the unlayering wheels  8 ,  9 . 
   Preferably, these rollers have two different diameters, one to be driven by the belt and the other larger diameter to disengage the folder from the lower belt so as not to drive it from below, when the blocking fingers  6  come to bear from above and no longer pinch it against the belt but against the idle roller which then stops. 
   The means for retaining the folders are constituted by at least one lever  11  pivotally mounted under the influence of a drive means such as a jack, relative to the support  5  and by a fixed belt  13  would about the lever  11  and the support  5 . 
   The belt  13  is fixed at one of its ends to the blocking finger  6  and at its other end to the fixed frame  3  at the upstream end of this latter. The support  5  movable relative to the fixed frame  3  is driven in the direction contrary to the direction of advance such that by recoiling the lever  11  and the support  5 , the fixed belt  13  unrolls and, being in contact with the folders of the layer  2 , gives rise to the successive stopping of the interleaved folders between said belt  13  and the path of the layer  2 , thereby reducing the interval of said folders. 
   This support  5  is drivable in movement by securement of said support under the influence of a gripping module  12  with a belt  14  driven in the reverse direction B to the direction of advance A between the upstream end and the downstream end of the fixed frame  3 . Preferably, the device also comprises rollers provided on the diagonal in the conveyor of the layer  2  of folders facing the fixed belt  13 , to perform the same function as the idle rollers, below the fixed belt  13  which unrolls. Thus, the last folder being extracted is also gripped by the fixed belt  13  which unrolls and hence also risks tearing by the extraction movement which is opposed to the gripping movement by the upper belt  13  which applies itself. 
   As can be seen from  FIG. 1 , when the first jack is actuated, the support  4  pivots toward the layer  2  and the roller  10  enters into contact with the layer  2 . 
   The blocking finger  6  is lowered simultaneously and slides on a folder which is thus located engaged between the roller  10  and the large unlayering wheel  9  ( FIG. 2 ). 
   The folder that is thus engaged is extracted by the unlayering belt  7 . As soon as the rear of the folder has cleared the roller  10 , the blocking finger  6  returned by the spring, pivots toward the layer  2  and blocks the following folder ( FIG. 3 ). 
   As soon as the length of interruption is obtained, the jack permits the support  4  to return to the inactive position ( FIG. 5 ). 
   Parallel to the lowering of the unlayering means and blocking means, the support  5  is also lowered such that the lever  11  rests against the layer  2 , the fixed belt  13  enters into contact with the layer  2 . 
   A gripping module  12  mounted on the support  5  then intervenes to pinch the belt  14  which moves in a direction opposite to the direction of advance of the layer  2 , such that the support  5  becomes secured to this belt  14 . 
   The driving movement of the support  5  and, as a result of the lever  11 , gives rise to the unrolling of the fixed belt  13  in contact with the layer  2 , which stops each folder to the extent the fixed belt  13  unrolls and has the result of reducing the interval between each folder. 
   When the interruption of the layer  2  is completed, the assembly of jacks is released, which drives the rising of the blocking finger  6  and the unlayering means, the rising of the lever  11  and the freeing of the support  5  and of the belt  14 . The fixed belt  13  rolls up again and returns the support  5  to its initial position ( FIG. 5 ). 
   The mentioned element, blocking finger  6 , fixed belt  13 , unlayering belt  7 , associated wheel  9 , roller  10  and lever  11  are described as being single but could also be, in the separation device according to the invention, two or more in number.