FR2645774A1 - Improvement to devices for conveying and sorting flat heterogeneous objects - Google Patents

Abstract

The subject of the present invention is improvements to devices for conveying and sorting flat heterogeneous objects. One of the applications of the invention is its use in sorting machines for sorting postal objects. The device comprises, inter alia, a known type of conveyor having trays 2 in which a front part of the flat surface supporting the objects 1 is inclined upwards and the rear part is closed by at least one stop 18 as a catch against the object 1 while it is being moved, but allowing the object to slide over the top when it is arrested by the sorting-ejecting system. The latter comprises at least one arresting comb 13 pivoting about an axis 14 situated forward of the downstream edge 21 of the target box 3, its flexible prongs 20 are approximately vertically above this edge: this comb 13 also has flexible non-return blades 27 under each prong 20 to help to immobilise said object during the ejection.

Description

Improvement of conveyor and sorting devices
heterogeneous dishes.

 The present invention relates to improvements to conveying and sorting devices of heterogeneous flat objects.

 The technical sector of the invention is the manufacture of an automatic machine comprising a plate conveyor. for sorting heterogeneous flat objects.

 One of the applications of the invention is the production of machines for sorting so-called flat postal objects. which objects are often heterogeneous by their geometry and by their weight.

 Many systems are known. Firstly. conveying and. on the other hand. sorting for objects having the above characteristics: in general, these systems are coupled with a first sorting and feeding device of the conveyor. then this one. which is closed loop most of the time in trays. and a second sorting device for evacuating objects from said trays to boxes arranged by destination.

 These various systems are developed by various manufacturers and are used by all the companies and organizations managing heterogeneous packages and flat objects. which are therefore transported flat in said trays of the conveyor between the supply device and that of evacuation and sorting proper.

 Indeed. the volume of postal mail is increasing regularly and it exists in parallel. more and more companies offering the sale of products by correspondence: the commercial volume of the corresponding market is growing. necessitating by the very keen competition between these companies and by the growing volume of letters, packages and objects to be distributed by the postal services, sorting machines having speed characteristics. more and more efficient and reliable.

Thus, some of these known sorting machines include conveyors. including the horizontal plates closed at the front and open at the rear. are driven one behind the other at a distance such that the objects placed flat on each tray can be stopped by fingers arranged in a comb, which drop vertically as they pass and push them so that they fall before the next tray , in a box placed below, which fingers are lowered on demand in front of the object, which was noted beforehand that it corresponded to the destination assigned to the box. which thus group together all the objects having this same destination
In order to prevent the object. especially if it is very thin. to bend under the push of the fingers and therefore to fall anyway into the box, the company CHAMBERLAIN MANUFACTURING CORPORATION
GARD DIVISION in ILLINOIS in the UNITED STATES rides on a linkage connected to the lowering mechanism of said fingers a spring presser which is supposed to keep the object pressed against the plate during its evacuation movement behind it, but the result is not very satisfactory and does not make it possible to increase the rate much, or to switch relatively thick flat objects.

 Regarding the conveyor feed system for loading the trays. they are generally injectors composed of a belt conveyor driving the objects by friction, slightly inclined and placed in the same axis above the main conveyor and provided with retainers raised through and between the conveyor belts and blocking each object one after the other, then lowering and releasing the object when an empty platform advances below: the band of the injection conveyor then drives the object so that it falls if possible in the platform with an identical linear speed, which is however rarely the case and many objects are badly positioned on the platforms. which makes sorting more critical.

 Various patents have also been filed. to clarify or improve certain parts of existing conveyors and equipment for sorting and indexing objects so that they are grouped automatically by destination, in order to reduce manual handling and speed up operations.

 The present invention relates to improvements to sorting machines, such as those described above. and whose objective is to ensure the grouping of objects according to the sorting directions, directly in boxes or containers, which objects are stored there flat. placed on top of each other.

 Indeed. in existing machines to date, several problems arise at different stages of operations: first, at the injector level, objects often fall between two plates which rotate without stopping to increase the sorting rate and even if the injector conveyor is adjusted at the same speed to drive said objects in isovelocity and in synchronization with the plates. some objects. and especially when they are too light and do not adhere enough to the strip by friction, are injected too slowly. and others, especially when they are too heavy, are injected in bursts. because they find it hard to accelerate suddenly.

 Then. at the level of the trays proper on the main supply conveyor between the injector and the sorting device by ejection switch. small objects are often ejected from their tray by centrifugal force in the curves always necessary to form a flat closed circuit conveyor and closed enough not to occupy too much surface, and light objects by the frontal aerodynamic resistance due to the linear speed of the conveyor.

 Finally. at the ejection sorting device. either the objects are stored vertically, but then they have to slide against each other. which is unrealistic for very heterogeneous objects and requires very complex mechanics. either they are stored horizontally. but then they have to keep this position during their fall and they don't hit the following plateau: this requires to space them well. increasing the aerodynamic problems raised above and reducing the sorting rate by reducing the number of trays possible for a given length of conveyor. In addition the ejection system out of the trays gives the objects a brutal impulse which tends to make them then fall into a spin and store anyway in the box below which is therefore quickly and poorly filled.

 All the problems mentioned above therefore limit the general speed of the machines and each operation being independent of the others. each must be improved for better overall effectiveness.

 The objectives of the present invention are then to be able to inject heterogeneous flat objects onto a horizontal conveyor with plates at certain isovelocity and in synchronization with the latter.

bring said objects on their tray without risk of parasitic ejection during conveyance to the sorting device proper and a switch in said device which allows an object to be stopped on demand to drop it flat in a box of destination given by passing under the next tray. all of these operations must be carried out at high speed without jerks. with the greatest flexibility and the least possible noise.

 One of the objectives is achieved with a device for conveying and sorting heterogeneous flat objects of the type comprising a plate conveyor. in a closed horizontal loop, the objects being placed flat on said trays, at least one injector of said objects introducing one by one each on an empty tray and at least one sorting system ejecting -each object in a box corresponding to its destination, characterized in that each of said plates made up of lamellae has at least one front part of the flat surface receiving said object inclined upward and forward obliquely. with respect to the horizontal and comprises. along its rear side at least one heel stop, against which object which it conveys can lean without sliding during its movement with said tray and on which the object can slide when it is retained by the sorting system .

Another objective of the invention is obtained with a device whose sorting system by referral with ejection of said objects comprises at least one stop comb, the fingers of which are tilted in front of the object which is to be ejected from its tray, characterized in that said comb is articulated around an axis located upstream of the downstream edge of the destination box which corresponds to it and is composed of straight parts ending in fingers. so that when said comb is lowered into the ejection position of said object in said box. these fingers are more or less vertical below the rear edge of the latter,
In a preferred embodiment, said comb comprises under each straight part a flexible non-return blade, the long side of the section of which is horizontal, of length almost equal to that of the straight part and of curvature in the vertical plane such that its end is slightly behind and above that of the corresponding finger. in order to leave sufficient space to avoid jamming of said objects.

 Another objective is achieved with a device whose injection system comprises at least one conveyor with continuously rotating belts and. inclined and fitted with a stopping comb which retracts below to release each object one by one. characterized in that said injection system comprises a second conveyor belt in the extension of the first equipped at its injection end with a belt presser device resting and blocking said objects from the first conveyor against this second conveyor . which conveyor is stopped and driven only when an empty plate appears under it. in such a way that the object is injected in iso-speed with said plate.

 The result is a new device for conveying and sorting heterogeneous flat objects which provides each of its main equipment. new improvements and improvements compared to known equipment. providing the same loading / injection functions. conveying and sorting / ejection.

 These improvements essentially make it possible to increase the speed of each operation. in addition ensuring a better reliable operation of the corresponding equipment and a higher rate. while increasing the efficiency and accuracy of it.

 So. tests could be carried out with a device according to the invention. with a conveyor advance speed of 1.7 m / sec for a drive from the inside, which leaves the possibility of further increasing this speed to 2m / sec with a drive from the outside. which then reduces the ejection phenomena due to centrifugal force when cornering, since it is the inner side which then slows down instead of the outer side accelerating.

 In addition, thanks to the particular shape of the trays and their inclination. these can be arranged very close to each other. or for example at 90 mm, which for trays of 260 mm in length. gives a footprint per tray of 350 mm and a possible rate of the above speed of 17,000 to 21,000 objects per hour, which is more than 20% higher than the best current devices and with greater reliability. Indeed, very few objects are lost in the present invention during operation by falling between two plates. while this frequently occurs in current systems and requires increased manual control.

 Finally. another advantage is the flat storage provided in sorting outlet boxes which takes place under very good conditions, whatever the characteristics of the objects, while this is often disturbed by falling into a spin in existing equipment.

 The following description refers to the appended drawings, without any limiting character, describing examples of embodiment of the conveying and sorting devices of heterogeneous flat objects. but other achievements can be envisaged.

 Figure l shows a schematic perspective view of an assembly of the device according to the invention comprising an injector. a conveyor, of which only a part has been shown. and a two-way sorting system ejector.

 FIG. 2 represents a schematic sectional view of a trijector system and of a plate.

 Figure 3 shows a top view of a trijector system and a tray.

 Figure 1 is a perspective view of an assembly of the device according to the invention, comprising. in a known way. an injector of heterogeneous flat objects 11 and 12, such as postal, such as letters, newspapers, periodicals, catalogs etc a tray conveyor 2, of which only a part has been shown. but which is in its complete closed-loop configuration and a sorting-ejector system of which only two destinations have been shown, each corresponding to a box 3.

 The injector can be placed at any point on the conveyor loop circuit and several can be installed as required: it injects said objects 1 as the trays 2 of the conveyor pass, passing below, at constant and continuous speed , which objects 1 are then ejected by the sorting system, which can also be arranged at any point of the circuit of the conveyor loop and can include the number of destinations and associated boxes 3 desired. If this number is important. the sorting system can be distributed at several points on the conveyor.

 To simplify the description and the representation, FIG. 1 represents only a simplified assembly grouping in a single zone of the conveyor, all the important parts necessary for the operation and objects of the improvements of the present invention.

 The injector comprises a first known conveyor 4 with belts.

continuously rotating and provided with a lower retractable stop constituted by a stop comb 5. whose fingers are arranged between the bands of said conveyor and which can pivot on demand downward to release said objects each time 11. In addition. flexible blades 6, the long side of which is horizontal are arranged in a fixed comb above this conveyor 4. so that their ends are slightly behind and above the ends of the fingers of said stop comb 5 .

 These blades 6 have the same shape and the same function as those described in FIG. 2 for the tri-ejector system; they should be long enough and slightly curved downward with their ends coming in. in the absence of objects 11, approximately at the level of the plane of the conveyor belts 4.

 So. when one of said objects 11 is placed on said conveyor 4. it is driven by the rotation of the latter against the fingers of the comb 5 raised. and then sliding under said fixed blades 6, these. on the one hand, keep it pressed against the conveyor and.

on the other hand, prevents it from vibrating and bouncing back as in known injector conveyors. When the stopper 5 is lowered, the object is released and instantly driven to the second conveyor 7. Said blades 6 are made of any material ensuring their rigidity and flexibility, such as for example steel.

 A second conveyor belt 7 located in the axis and in continuity of the first, receives said objects 1 thereof. and brings these towards its end 8 near which a system of belt pressers 9 comes into permanent abutment and immobilizes against the belts of said conveyor 7 the object 12 when these are stopped: indeed. this second conveyor 7 only rotates to load an object 1. then to eject it. the rest of the time, it is stationary.

 Said pressers 9 are mounted for example on a fixed common axis from which springs keep them in abutment against them while leaving them the possibility of rising up when an object 12 passes by maintaining sufficient pressure thereon to keep it on hold, once part of its front edge is engaged on the end 8 of the injection conveyor 7.

 Preferably, said front edge of the objects 1 is the largest and this preferential direction has been previously chosen in a known manner before the loading of the first conveyor 4.

 The assembly of the two conveyors 4 and 7, the belts of which are in the same upper plane receiving the objects l, is slightly inclined towards the main plate conveyor 2 and located in the same axis of movement as the latter.

 So. when any known system for detecting objects placed upstream on the trajectory of the plates 2, signals that whatever is going to appear under the end 8 of the injection conveyor 7 is empty.

it can be ordered to inject said object 12 into said tray 2.

 This detection. then the injection control is carried out automatically by any known means. and the presser device.

associated with the conveyor 7 which starts and rotates at the same speed as that of the plates 2, with a given speed-up law then makes it possible to inject said object 12 in isovelocity with the plate 2 which is presented: thus. the object falls into it, without relative longitudinal displacement. and remains in good place, when the plate continues its conveying, while in known injection systems which use friction only as with the belts of the conveyor 4 when the stop comb 5 is retracted. the objects are ejected at a variable speed according to their characteristics and difficult to control, because the acceleration which is communicated to them is low.

 In the system according to the invention, the presser assembly 9 prevents slipping between the objects and the conveyor 7. the latter having a given and known speed setting law in order to perfectly synchronize the injection.

 The plates 2 as described in Figures 2 and 3 below are hooked on a track to each other and therefore drive each other on the closed loop circuit of the conveyor they constitute.

 These plates 2 have a flat and thin horizontal part on one of their lateral sides and protruding beyond these. so that the drive of said conveyor is carried out by adhesion of at least one belt 10 against said horizontal part 11 of several consecutive adjacent plates 2.

 In one embodiment, said drive comprises at least two belts 10. driven by any motorization and roller system 12 ctnnu, in such a way that they are pushed towards each other and pinch said horizontal portions between them 11 of said plates 2 and drive them by friction.

 For example, said rollers 12. of which only one can be a motor, can be placed one above the other in pairs. each driving or driven with one of the two belts 10. and thus connected two by two by a spring which tends to bring them together, thus maintaining a pressure between the two belts which pinch and then frictionally drive the horizontal parts 11 of said plates 2; the rollers 12 are distributed along the length of the belts to distribute the gripping force over several plates.

 In another embodiment. said drive comprises a single magnetic belt 10. and said horizontal hor-zontal part 11 is metallic so that the training takes place by adhesion. In this embodiment. there is no longer any need for intermediate rollers 12 between the ends.

 In the above drive modes and the example of FIG. 1. the belt 10 has a length sufficient to adhere to three consecutive plates 2, but depending on the drive effort required. it can be longer or longer. even to reduce local forces on the chain of chainrings. several drive systems of this type can be distributed along the conveyor, the flexibility of the grip drive then avoids mechanical forces in the transmissions, allows sliding between two drives and can ensure appreciable silence in operation.

 The minimum length of the belt 10 is equivalent to the length of two consecutive trays to be sure that there is always one driven.

 Thanks to its compactness, said drive system can be placed inside or outside the closed loop circuit of the conveyor: inside. it gives outside access to all the platforms. but causes centrifugal accelerations in the curves. while outside. it avoids this last point.

 In particular, the belt drive system 10 can be placed in the same place as the sorter-ejector system. This is described in Figure 2 and includes by destination a stop comb 13 articulated around an axis 14 and a horizontal storage box 3. Thus, when an object 13 is located on the path of the conveyor by any system known automatic recognition. and then associated with a destination corresponding to a box 3. it is stopped by the comb 13 corresponding to this, while the plate on which it is placed continues its movement on the conveyor. Thus, as shown here, the object 14 stopped by the comb 13. slides relatively back relative to the plate 24 which transports it, passes under the next plate 23 to then fall horizontally vertically into the box 31 corresponding to its previously recognized destination.

 Figure 2 shows a schematic sectional view of a tri-ejector system. as shown in perspective in FIG. 1. We see that the comb 131 lowered around its axis 14.

blocks the object 14 which is then ejected from the tray 24 to fall into the box 31
Each of the plates 2 a. in a known manner, a kind of inclined front spatula 15. serving as a ledge and may include; a part. horizontal 16 back of the flat surface. on which the object 1 is based.

 Each plate has at least one flat front part 17 on which the object thus rests. inclined upwards and a retainer 18 making a heel. against which the object can lean without sliding during the movement of the plate and on which it can pass when it is ejected from it by the comb 13.

 This retainer 18 thus prevents sliding in a straight line due to the aerodynamic effect on the object 1 and in the curve by the centrifugal effect. It can be a continuous spring blade over the entire rear edge of the plate, or only at certain points, or a solid part molded with the plate, or an elastomer blade with a high coefficient of friction.

 The inclined part 17 behind the spatula 15. if it concerns only part of the support surface of the plate 2, then provides with the rear flat part 16. a pre-curve to the objects 1 and during impacts the comb 13. prevents buckling of these objects by pressing them down against the plate, by pressing between the comb 13 and the retainer 18: the objects thus stiffened, can then pass over the latter. without the risk of swirling. by bending up. as is the case with trays having a continuous planar surface.

 Furthermore. the inclination of this flat surface 17 over a part of the plate or over its entire surface makes it easier for objects 1, especially thick objects, to pass between two plates during ejection, this allows the distance between them to be reduced and therefore d '' increase the processing rate for a given conveyor movement speed. itself limited by aerodynamic effects on objects.

 Said comb 131 is composed of a straight part 19, ending with fingers 20 and is articulated around its axis 14 so that. in the raised position, it allows the trays 2 to pass without touching them and, in the stopped position, said fingers 20 are more or less vertical below the downstream edge 21 of the box which must receive the object 1: the trays being constituted in a known manner, as as described in FIG. 3. of strips, said fingers are placed between these strips and can descend below the bearing surface of the objects.

 This straight part 19 is long enough for the descent of the fingers 20 to be almost vertical and creates a dihedral blocking the object between the plate and itself: in addition, said stop combs 13 are flexible, such so that their end fingers 20 can deform slightly when stopping objects 1. to allow a gentle deceleration of these, especially when they are heavy, to reduce stress, vibration and also then noise.

 Finally, said comb 13 comprises, under each straight part 19, a flexible non-return blade 27. whose long side of the section is horizontal, of length almost equal to that of the straight part and of curvature in the vertical plane. such that its end is slightly behind and above that of the corresponding finger 20. in order to leave sufficient space to avoid jamming of said objects 1.

 This non-return blade 27 limits the backward movement of the objects 1, including when there is deformation of the flexible comb 13 and keeps the front of the object 1 supported on the plate 2 to avoid buckling at the time of the impact d 'stop.

 The combination of the various improvements above ensures a controlled and flat fall such as the object 15 in the box 32 corresponding to its destination.

 The trays are driven on the conveyor by the system described in Figure 1 and each roll bearing on two rollers 22 located on each side of the trays as described in Figure 3. rolling themselves on the fixed tracks of the conveyor .

 FIG. 3 represents a top view of an ejector sorting system and of a plate 2. This is constituted, in a designed manner. lamellae 23 spaced between which can tilt the fingers 20 of the comb 13 rotating around the axis 14: one of these lamellae may include a stop 24 placed under its flat part receiving said objects 1. longitudinally in the axis, such so that small objects rest on it laterally in the curves and large objects cover it.

 These strips 23 are carried in a known manner by a frame which is supported vertically. on the one hand, on rollers 22 and, on the other hand, on horizontal rollers 25 which guide the plate on the conveyor circuit. Each plate 2 is connected to the adjacent plates by articulations 26 with a vertical axis which allows them to form a chain and to rest on each other.

 These plates 1 also include, as described in FIG. 1. a horizontal part It extends beyond them to ensure their entrainment by adhesion by at least one belt 10.

 All motors and motorization and belt movement systems. bands and combs. can be activated by any known power supply such as electric, pneumatic or hydraulic. For questions of silence. flexibility and speed, and to avoid the problems of inertia of fluids and movements. the drives are preferably pneumatic.

All markings and codings. and corresponding movement controls are provided by any known automatic processing system.

 The present invention is not limited to the embodiments described above and which constitute only examples of devices according to the invention and modifications and variants can be made within the framework thereof.

Claims (11)

 1. Device for conveying and sorting heterogeneous flat objects of the type comprising a plate conveyor (2) in a horizontal closed loop. the objects being placed flat on the trays at least one injector (4) of said objects (1) introducing one by one each on an empty tray and at least a sorting system ejecting each object (1) into a corresponding box (3) at its destination, characterized in that each of said plates (2). made up of lamellae. has at least one front part of the flat surface (17) receiving said object (1) inclined upwards and forwards with respect to the horizontal and comprises. along its rear side at least one stopper (18) forming a heel, against which the object which it conveys can rest without sliding during its movement with said plate (2) and on which the object can slide when it is retained by the sorting system,  2. A device for conveying and sorting heterogeneous flat objects according to claim 1, characterized in that each of said plates (2) has a horizontal rear part (16) of the flat surface receiving the object (1).  3, device for conveying and sorting heterogeneous flat objects according to any one of claims 1 and 2. and the sorting system by referral of said objects (1) comprises at least one stop comb (13). whose fingers are tilted in front of the object (1) which must be ejected from its tray (2). characterized in that said comb (13) is articulated around an axis (14) located upstream of the downstream edge (21) of the destination box (3) which corresponds to it and is composed of straight parts (19) ending by fingers (20). so that when said comb is lowered into the ejection position of said object in said box (3). these fingers are approximately vertical plumb with the rear edge (21) thereof.  4. Conveying and sorting device of heterogeneous flat objects according to claim 3, characterized in that said combs (13) stop are flexible. in such a way that their end fingers (20j can deform slightly when the objects (1) stop.  5. Conveying and sorting device of heterogeneous flat objects according to any one of claims 3 and 4, characterized in that said comb (13) comprises under each straight part (19) a blade (27) flexible non-return , whose long side of the section is horizontal. of length almost equal to that of the straight part and of curvature in the vertical plane, such that its end is slightly behind and above that of the corresponding finger (20). in order to leave sufficient space to avoid jamming of said objects (1).  6. A device for conveying and sorting heterogeneous flat objects according to any one of claims 1 to 5, and the injection system of which comprises at least one conveyor (4) with continuously rotating belts and. inclined and provided with a comb (5) stopping retracting from below to release each object (11) one by one. characterized in that said injection system comprises a second conveyor (7) with belts in the extension of the first equipped at its injection end (8) with a pressure device (9) with belts resting and blocking said objects (12) coming from the first conveyor (4) against this second conveyor (7). which conveyor is stopped and driven only when an empty plate (2) is present under it, so that the object (13) is injected at low speed with said plate (2).  7. Conveying and sorting device of heterogeneous flat objects according to claim 6. characterized in that said first conveyor (4) with bands of the injector comprises flexible blades (6) arranged in a fixed comb, the long side of which of the section is horizontal and above this conveyor (4 ;. so that their ends are slightly behind and above the ends of the fingers of said stop comb (5).  8. A device for conveying and sorting heterogeneous flat objects according to any one of claims 1 to 7, characterized in that each of said plates (2) has a horizontal and flat part (11) which is thin and flat on one of their lateral sides. and protruding beyond them. in such a way that the drive of said conveyor is carried out by adhesion of at least one belt (10) against said horizontal part (11) of several consecutive adjacent plates (2).  9. Device for conveying and sorting heterogeneous flat objects according to claim 8. characterized in that said drive comprises at least two belts (10), driven by any known motorization and roller system (12), in such a way that they are pushed towards each other and pinch between them said horizontal parts (11) of said plates (2) and cause them by friction.  10. Conveying and sorting device of heterogeneous flat objects according to claim 8. characterized in that said drive comprises a single magnetic belt (10). and said planar horizontal part (11) is metallic so that the drive takes place by adhesion.  11. Device for conveying and sorting heterogeneous flat objects according to any one of claims 1 to 10. characterized in that each of said plates (2) comprises a stop (24) placed on a strip of the flat part receiving said objects (1). longitudinally in the axis, so that the small objects rest on it laterally in the curves and the large objects cover it.