FR2631321A1 - Device for unpiling non-standard flat articles - Google Patents

Abstract

The unpiling device includes a magazine 1 for storing the piled flat articles, having an unpiling edge 5 and a jogging edge 6, between which edges an article outlet 7 is defined, and first means 2 of entrainment and of permanent underpressure (partial vacuum), these means being interposed on the said unpiling edge upstream of the outlet of the magazine, defining an article-taking line 20 for imparting speed to the successive articles in contact on this line, and second means 3 of extraction at a speed greater than that of the first means defining substantially on the plane of the unpiling edge, downstream of the outlet of the magazine, a point for gripping the said articles 30 in order to extract them from the article-taking line 20. Application: unpiling of postal covers to be sorted.

Description

Unstacker of non-standard flat objects.

 The present invention relates to unstackers of non-standard flat objects, such as in particular postal folds.

 Such destackers are in particular used for feeding separate plies to a postal ply sorting machine. The envelopes are initially loaded in a stack in a storage warehouse.

The storage magazine presents the stack of folds to the destacker. The destacker removes and ensures the setting in speed of the folds delivered individually to the sorting machine.

 The folds of the stack to be loaded in the storage magazine have different dimensional characteristics between them.

Before loading, the stack of folds can be hand-teased for the approximate alignment of the folds on one of their edges, which will be the front edge of the folds in the storage magazine for the destacker. Advantageously, in the storage magazine, the folds of the charged stack are also also jogged against a jogging edge on which the outlet of the magazine folds is formed.

In a known way? a set of rollers on the bottom of the magazine can for example ensure this jogging of the folds against the jogging edge.

 Known destackers can be classified into two main families, depending on whether they ensure the gradual separation of the plies or the direct unitary separation of the plies taken from the Storage store.

 The destackers of the family with progressive separation of the pleats implement a phenomenon of "natural" friction of the plies entrained through the outlet of the store.

 They use separating elements, for example belts and counter-belts or rollers and counter-rollers or friction pads, mounted downstream from the outlet of the store. These are mechanical elements that hold one of the folds of a possible double grip to allow delivery of only separate unit folds to the sorting machine.

 The destackers of the family with direct unitary separation use a "positive" friction phenomenon for the unitary removal of the folds of the magazine. They use a vacuum device controlled on each desired sampling, for effective contacting of the terminal fold of the stack against drive elements.

This member is for example a vacuum wall or a drum or a vacuum belt, with which are associated means for driving or also ensuring, as the case may be, the driving of each fold through the outlet of the magazine. The depressurization of this member which is controlled at successive moments of ply sampling makes it possible to deliver separate plies one from the other.

 The destackers of the first family referred to above are robust materials which are not very prone to breakdowns and are therefore functionally reliable; their performance remains limited, mainly due to the lack of control over the interval between. the separate folds delivered to the machines they feed.

 Those of the second family, on the other hand, have high performances, thanks to the control of the time of departure of each fold of the store, leading to a very good control of the flow of the folds with a constant interval between them; on the other hand, their reliability is relatively limited, essentially due to the use of relatively sophisticated control circuits and in general of limited lifetime which they require, for obtaining very rapid response times.

 The object of the present invention is to provide a destacker which has both high friability and high performance characteristics, that is to say which, at the same time, is of reliable operation over time and allows obtaining a constant interval desired between the folds delivered.

 The present invention therefore relates to an unstacker of non-standard flat objects, comprising a magazine for storing said objects in a stack equipped with an unstacking edge and a jogging edge transverse to said unstacking edge, between which is defined. an outlet of objects from the store, and comprising unstacking means associated with the store, characterized in that said unstacking means comprise first drive means and continuous depression, flush with the plane of said unstacking bank in the store storage, upstream and parallel to the outlet of the store, substantially along a line for picking up objects successively speeded up on this line, and second extraction means, of extraction speed greater than the drive speed first means, substantially defining on the plane of said unstacking bank, downstream of said store outlet and at a distance from said object pick-up line less than the minimum length the objects, a pinch point of said objects, to extract the objects from said object picking line and deliver them unstacked.

 According to another characteristic of the invention, the destacker further comprises auxiliary means for depressurizing at least a portion of the unstacking edge, upstream of the line for picking up objects relative to the outlet from the store. , at a low vacuum value relative to that created by said first means.

 In the destacker according to the invention, the successive objects are each placed against the unstacking edge as the object being unstacked is released and put into gear as soon as they come into contact with the gripping line of objects. Successive objects leave the store tiled, while the second extraction means deliver them separate, with a constant interval between them.

 The characteristics and advantages of the present invention will become more clearly apparent during the description below of an exemplary embodiment illustrated in the attached drawings.

In these drawings
- Figure 1 is a schematic top view. partially cut off from the destacker according to the present invention,
- Figure 2 is a schematic sectional view of the destacker, taken along line II-II of Figure 1.

 The unstacker according to the invention, illustrated in FIG. 1, comprises a storage magazine 1 receiving flat articles in a stack and unstacking means formed essentially by a unstacking head 2 and an extraction member 3 associated with the head of unstacking.

 The unstacker illustrated is intended to supply a postal ply sorting machine loaded in a stack in the store. It delivers to the sorting machine folds separated from each other which are presented to it vertically.

 The storage magazine is provided for this purpose to receive the folds stacked vertically.

 The sotckage store 1 has a bottom 4 on which the feet of the folds in a pile rest, a unstacking edge 5 and a jogging edge 6. The edges 5 and 6 are substantially vertical and transverse to each other. An outlet 7 for the first fold to be taken from the stack is defined vertically between these two banks. A flexible lip 8 is fixed on the edge of the jogging edge and limits the passage through the outlet 7. A pallet 9, coming to bear against the last fold of the stack loaded in the storage magazine, ensures the retention of the pile of folds. The stack of folds is loaded by hand in the magazine. She was not represented to clearly see the organization of the destacker.

 The storage magazine 1 is equipped, on its bottom 4, with advancing means according to the arrows 10 of the folds towards the unstacking bank and with jogging means according to arrow 17 of the folds towards the jogging bank. These advancing means according to arrow 10 comprise on the one hand a set of belts 12 and on the other hand a set of threaded rollers 13. The belts 12 extend from the rearmost part of the magazine towards the front part of the store without however coming to the terminal part - before. The threaded rollers 13 extend the action of the belts to this front end portion. They are mounted in the front part of the store, interposed between the belts which terminate there. The jogging means according to arrow 11 are also mounted in the bottom of the magazine. They consist of a set of smooth rollers 14, mounted in the front part, which are interposed between the helical rollers 13 and come in the extension of the belts 12.

 A first detector 15, of the capacitive type, is mounted in the bottom of the storage magazine, in its front part. It is located at the end of one of the belts 12, between this belts and the smooth roller 14 which extends it and is made shorter for this purpose. This first detector is assigned to the belt drive control when it detects an absence of folds in the front part of the magazine.

 A second detector 16, of the pressure type, is mounted on the unstacking bank 5, towards the outlet 7 of the magazine. It is fixed by elastic means making it slightly protruding on the unstacking face, in the absence of folds against the unstacking edge.

It is assigned to the drive control of the threaded rollers 13 when it detects an absence of folds against this unstacking edge.

The smooth rollers 14 are in turn driven continuously.

 A single motor, not shown, drives the smooth rollers 14 and through two individual clutches drives the belts 12 and the threaded rollers 13 in advance. These clutches have not been shown, one is controlled by the first detector 15 and the other by the second 16.

 In the destacker according to the invention, this arrangement of storage magazine receiving the folds stacked vertically on its bottom and its equipment for advancing the folds are given only by way of example and for the application referred to above. to a vertically present ply sorting machine.

 For different applications, the magazine can be designed to receive folds stacked horizontally or with a slight inclination on the horizontal, with the first fold to be taken at the bottom of the stack and resting on the bottom of the magazine. Under these conditions, the bottom of the magazine then also constitutes the unstacking bank and the outlet of the magazine folds is defined horizontally above the bottom or unstacking bank by a jogging bank.

 The unstacking head 2 and the associated extraction member 3 are mounted relative to the unstacking edge 5. The unstacking head 2 is constituted by a rotary drum with permanent vacuum, designated by this reference 2, which is said to be the main drum . The periphery of the main drum 2 is flush on the plane of the unstacking edge 5 against the first fold to be taken from the magazine 1.

It defines a ply line 20, on the unstacking bank 5, upstream of the outlet 7 and at a relatively small distance from the outlet 7. It ensures by suction an effective and immediate contact against its periphery of any loose fold in front of the fold-taking line 20 which it immediately passes towards the exit 7. The arrow 21 symbolizes the aspiration which is achieved and by the arrow 22 its rotation, for the setting in motion of the clear fold appearing on the line 20.

 A support plate 70 defines the bottom of the outlet 7 across the width of the magazine and towards the extraction member 3. This support plate 70 extends beyond the unstacking edge opposite the storage magazine and has a crenellated edge which fits into the end of the rollers 13 and 14.

 The main drum 2 comprises a rotary external cylinder 24, and, fixedly mounted inside the cylinder, an axial vacuum line 25 and at least one communication channel 26, transverse to the line. The cylinder 24 has its permeable or perforated wall.

It is shown in Figure 1 with multiple perforations 27 over the entire wall. The vacuum line 25 is connected to a source of vacuum not shown. The communication channel 26 is connected to the vacuum line 25 and opens onto the internal face of the cylinder facing the store, slightly framing, on either side, the line 20 for taking folds on the periphery of the drum. Advantageously, as shown this channel is not centered on the line 20 of the pleat hold, but slightly offset towards the outlet 7 of the store. It thus makes it possible to print at the fold, applied against the line 20, a deformation at its front frontal part, for its passage under the lip 8 equipping the outlet 7.

 The extraction member 3 associated with the main drum 2 is constituted by a pair of designated drive belts. by 3A and 3B. These belts define between them a pinch point 30 of the folds successively set in speed by the main drum, downstream of the outlet 7 and approximately in the plane of the unstacking edge 5; they are driven to print folds, successively set in speed by the main drum and pinched together at point 30, an extraction speed greater than that known as drive given by the drum 2. As shown, advantageously the point of nipping 30 is slightly offset from the plane of the unstacking edge, on the side of the jogging edge 6.

This pinch point 30 is also at a distance from the grip line 20 on the main drum 2 less than the minimum length of any fold of the stack of folds to be unstacked.

 These belts 3A and 3B are mounted tensioned between pulleys; there is simply shown, for both, the two end pulleys 31 and 32, on the side of the outlet 7 of the store. The pulley 31 for the belt 3A has a diameter greater than that of the pulley 32; it essentially extends over the outer face of the unstacking edge and has its periphery which projects slightly on the plane of this unstacking edge. The pulley 32 of smaller diameter, for the belt 3B, is opposite the end portion of the unstacking face 5 and is very close to the outlet 7; it remains largely behind the outlet 7 with its lip 8 and in front of the unstacking edge.

 A tension pulley 33 for the belt 3B is biased elastically under pressure against the pulley 31, to define between the belts 3A and 3B the pinch point 30. It also makes it possible to provide, between the output 7 and the pinch point 30, an upstream passage without pressure exerted on the fold driven by the only main drum 2 to the pinch point 30. Downstream of the pinch point, the belts 3A and 3B constitute a feed conveyor for a downstream machine, such as the aforementioned sorting machine not shown. An arrow 35 indicates the supply of this machine with folds delivered by the destacker.

 -In the destacker according to the invention, the unstacking means formed essentially by the main drum 2 and the extraction member 3 are also associated with auxiliary means cooperating with the main drum 2. These 'auxiliary means comprise an auxiliary drum 40, upstream of the main drum 2 along the unstacking edge, the unstacking edge itself and a box 50 formed on the unstacking edge.

 The auxiliary drum 40 is a rotary drum with permanent vacuum, like the main drum 2. It is mounted just upstream of the main drum on the unstacking bank; its periphery is flush with the plane of the unstacking edge 5 in the magazine.

It has a lower vacuum than that of the main drum, as well as a lower speed than that of drive given by the main drum 2. The periphery of the auxiliary drum 40 and that of the main drum 2 interposed through the unstacking edge 5 define, with this bank, the unstacking face.

 The auxiliary drum 40 comprises, like the main drum 2, a rotary external cylinder 41 with a permeable or perforated wall, and, fixed inside the cylinder, an axial depression pipe 42 and at least one radial channel 43 communicating with the pipe and opening onto the internal face of the cylinder 40 facing the first fold of the magazine. Line 42 is connected to a source of vacuum not shown. The action of this auxiliary drum 40 on the first fold of the stack is not preponderant on that of the main drum 2.

 The arrow 44 illustrates the depression exerted by this auxiliary drum and the arrow 45 its rotation. This auxiliary drum 40 ensures, during the removal of the first ply from the stack, perfect jogging of the next ply against the jogging edge, as soon as this ply is released in front of it. The rotary cylinder 41 has been shown with perforations 46 over its entire periphery.

 The unstacking edge 5 constitutes one of the walls of the box 50, it extends beyond the box towards the pinch point 30 and towards the opposite to extend over the entire width of the magazine.

It has a vertical line 51 of slight fold just downstream of the auxiliary drum 40.-On either side of the line 51, it thus has a front portion 5A in front of the outlet 7 of the store, which is transverse to the bank of jogging, and an opposite rear part 5B, which extends slightly at an angle on the storage magazine.

 The box 50 is also a vacuum box, of low value relative to that of the auxiliary drum 40 and a fortiori of the main drum 2. It contains the two drums 2 and 40; it has been shown cut at its upper part to see more clearly the two drums it contains.

 The unstacking edge 5 is porous or perforated at least at the level of the box. A suction channel 52 opens into the box 50 through its side wall opposite the unstacking bank.

Associated with the suction channel is a suction means, not shown, which is for example constituted by a simple fan, taking into account the desired low vacuum. An arrow 53 translates the suction produced from the suction channel 52. The portion of unstacking edge constituting one of the walls of the box 50 is represented with multiple perforations 54.

 In Figure 2 there is shown schematically this same destacker seen in section through the box 50 in front of the drums 40 and 2 for its unstacking means. We see there for the advance and the jogging of the folds 60 in the storage magazine 1 of the drive pulleys, such as the pulley 17 for that of the belts 12 shown, which is under the front part of the magazine, the pulley 18 for that of the advance threaded rollers 13 shown, which is under the magazine between the belts 12, and the pulley 19 for that shown of the smooth jogging rollers 14, which is below the level of the magazine but outside the bank of unstacking 5. These pulleys 17, 18 and 19 allow, by belt transmissions not shown, the driving of the advance belts 12 and of the rollers 13 and 14 from a same motor not shown, the advance controls for the belts 12 and the rollers 13 being given by the aforementioned detectors assigned for this purpose.

 In this FIG. 2, it can also be seen that the drive of the auxiliary drum 40 is ensured by a friction pulley 47 mounted in the box and under pressure against the body of the cylinder 41.

The shaft of this friction pulley leaves the box and carries a drive pulley 48. The drive of the main drum is in turn provided by a pulley 28 mounted on its body. Belt transmissions 29, 49 couple the drive pulleys 28, 48 of the drums 2 and 40 to the aforementioned motor.

 Figure 2 further shows the arrangement of the main drum 2 and the auxiliary drum 40 relative to the level of the bottom on the outlet of the storage store, defined. by the support plate 70.

 The main drum 2 has its outer cylinder. rotary and placed under vacuum 24 which extends substantially from the level of the support plate 70 to halfway up the magazine. The auxiliary drum 40 has its rotary cylinder set to vacuum 41 of lesser height. It is appreciably centered at mid-height of the cylinder 24 t is of a height of the order of two to three times less. These comparative dimensions and the different depressions they produce on the destacking race make the action of the main drum 2 predominant over that of the auxiliary drum 4D.

 By way of example, it is specified that the vacuum value exerted by the main drum is of the order of 500 m bars, that exerted by the auxiliary drum is from 100 to 200 m bars, that exerted by the vacuum chamber 50 therefore by the unstacking edge 5 is 10 to 20 m bars. As the first fold of the stack emerges in front of the unstacking bank, the next fold tends to press against this bank, the auxiliary drum strengthens the action of the bank on a limited area of the unstacking face unstacking; the main drum accentuates very strongly, on the fold take-up line 20 near the exit from the store4, the preceding actions alone leading to the removal of the fold practically cleared entirely in front of the unstacking bank and to its speeding up through the exit of the shop.

 In operation, as appears from the description of FIG. 1, the fold line 51 on the unstacking bank and the offset of the depression exerted by the main drum 2 with respect to its fold take line 20, towards the outlet of the store, each print a slight deformation to the fold released at their level and already pressed against the unstacking bank. The passage under the lip 8 of the front edge of the fold in contact with the main drum 2, therefore put into gear by this drum, is thus favored.

 This setting in speed of the fold to be taken up is carried out almost instantaneously by the main drum, as soon as there is contact of this fold on the grip line 20.

 The sampling takes place at the speed that the main drum 2 gives to this fold, until the front edge of the fold reaches the pinch point 30 defined by the extraction member 3.

 At this instant, the strongly pinched fold receives the extraction speed given to it by the extraction member 3. This change in speed has the effect of "tearing" the fold from the main drum, by sliding, from the rear part. of this fold, still pressed and driven against the drum, on the periphery of this drum.

 The rapid release of the rear edge of this fold of the drum leads to the release of the next fold in front of the fold line 20 of the main drum and to speed it up in turn.

Before the departure of this next fold from the store, the front face of this fold is tacked against the jogging edge 6 and the lip 8 by the auxiliary drum 40. When it leaves, its front edge always overlaps the rear part , still in the store, from the previous fold being extracted. They leave the store with the rear part of the previous fold. The successive folds therefore come out tiled through the exit 7 of the storage store, the lip 8 opposing the passage of the folds not in direct contact with the main drum for their implementation. speed.

 From the instant of release of the rear edge of a fold of the drum, which gives the instant of departure of the next fold, the high speed of extraction of the first fold and the lower speed of training of the next fold, on the one hand, and the distance between the ply line 20 and the outlet 7 of the magazine and that between the pinch point 30 and the outlet 7 of the magazine, on the other hand, are the only characteristics of the destacker which lead at a constant interval between depilated folds that it delivers. The value of this constant interval is also easy to optimize for the machine supplied by the destacker.

 This interval between successive depilated folds is given from the time interval separating the arrival at the pinch point 30 of the rear edge of a fold, extracted at the speed of the extraction member, from the arrival at this same point on the front edge of the next fold, set in speed by the main drum 2. Beyond this pinch point 30, the two folds concerned have the same speed.

- l'intervalle i entre plis successifs est alors
i = (t2 - tl) Va soit

ou

By designating by Ve the speed of pleating by the main drum 2, Va the extraction speed at the pinch point 30 or speed of feeding of the machine in plies unstacked by the destacker, d1 the distance between the line 20 for the pleating by the main drum 2 and the outlet 7 from the magazine, and d2 the distance between the pinch point 30 and this outlet 7 from the magazine - the instant tl of arrival at the pinch point 30 of the rear edge of the fold during extraction and the instant t2 of arrival at the same pinch point 30 of the front edge of the next fold, defined from the common instant of release of the rear edge of the first considered fold of the drum and speed of the next fold, expressed by

- the interval i between successive folds is then
i = (t2 - tl) Go either

or

 For defined values of the characteristic parameters dl, d2, Ve, and Va of the destacker, the interval i between folds is therefore constant, regardless of the length of the folds. It can be easily optimized by the choice of the values given to these characteristic parameters, with however the sum dl + d2 remaining less than the minimum length of the folds.

In addition, for folds whose average length is 1, the flow rate q of the folds delivered is

 This flow q can itself be optimized by choosing the interval i to its minimum possible value in the machines fed by the depilated folds.

 The present invention has been described with reference to the illustrated embodiment. It is of course possible to modify it in detail and / or replace certain means with others which are technically equivalent, without going beyond the ambit of this invention.

Claims (9)

CLAIMS: 1 / Unstacker of non-standard flat objects, comprising a magazine for storing said objects in a stack equipped with an unstacking edge and a jogging edge transverse to said unstacking edge, between which an object outlet is defined of the magazine, and comprising unstacking means associated with the magazine, characterized in that said unstacking means comprise first means (2) for driving and continuous depression, flush with the plane of said unstacking bank (5r in the magazine storage (1), upstream and parallel to the outlet (7) of the store, substantially along a line (20) for picking up objects successively speeded up on this line, and second extraction means (3), extraction speed greater than the driving speed of the first means, defining substantially on the plane of said unstacking bank (5), downstream of said outlet (7) from the magazine and at a distance from said gripping line d objects less than the minimum length of the o bjets, a pinch point (30) of said objects, to extract the objects from said object picking line and deliver them unstacked. 2 / destacker according to claim 1, characterized in that said first means (2) consist of a rotary main drum and continuous vacuum. 3 / destacker according to claim 2, characterized in that said main drum has a fixed internal channel of continuous depression (25, 26) opening on its periphery on either side of said object picking line (20), by being off-center on said line for taking objects, towards the outlet (7) of the store.  4 / destacker according to one of claims 1 to 3, characterized in that said second means (3) comprise a pair of driving belts (3A, 3B) coming substantially opposite the outlet (7) of the magazine (1) in pressure one against the other to define said pinch point (30). 5 / destacker according to claim 4 characterized in that said pinch point (30) is formed back from said plane of the unstacking edge (5), on the side of the jogging edge (6).  6 / destacker according to one of claims 1 to 5, characterized in that it further comprises, on at least a portion of the unstacking edge, upstream of said object picking line (20) relative to the leaving the store, auxiliary means (40, 50) for depressurizing said unstacking bank to a value less than the depression created by said first means (2). 7 / destacker according to claim 6, characterized in that said auxiliary means comprise an auxiliary drum (40) rotary for continuous vacuum flush with the plane of said unstacking bank (5) in the storage magazine, upstream of said line for picking up objects (20), and driven at a feed speed lower than that of driving said first means (2).  8 / destacker according to claim 7, characterized in that said unstacking bank (5) has a line of slight fold (51) between said line for taking objects (20) and said auxiliary drum (40). 9 / destacker according to one of claims 6 to 8, characterized in that said auxiliary means comprise a continuous vacuum box (50) on the unstacking bank itself (5) made permeable on at least one portion adjacent to said line taking objects (20), upstream of this line.