FR2759355A1 - DEVICE FOR STACKING AND UNPILING WORKPIECE SUPPORTS - Google Patents

Abstract

The invention concerns a device comprising: a lift system (12) for raising and lowering a stack (24) of part supports (2), a retaining prehensile device (20), located above the lift system (12), and means for loading and/or unloading the parts (4) from their supports (2) and arranged between the lift system (12) and the prehensile device (18).

Description

 The present invention relates to a device for stacking and unstacking workpiece supports.

 For the manufacture of terracotta objects, such as for example bricks or tiles, the objects are first shaped, then dried and finally cooked.

Certain clays used for the manufacture of these objects have a high shrinkage rate. To avoid deformation of the part during cooking and to maintain the geometry of the product, each part is placed on a unitary support. Thus, during cooking, each piece can retract independently of the others while keeping its geometry.

 During the various stages of the manufacture of terracotta objects, each object is placed on a unitary support and does not leave it until it is cooked. Each object manipulation is done with the corresponding support. In terms of cooking, many manipulations of supports are carried out. The supports, each provided with a dried part, are placed on a cooking trolley. The supports are then taken one after the other and are deposited so as to form a stack. Several stacks of media are placed on a cart and the cart goes through a baking oven. At the exit of the oven, the supports are unstacked by removing the supports one after the other and depositing them on a conveyor, then the baked object is removed from its support, the latter is cleaned, possibly turned over and finally a dried clay object is placed on the clean support.

 Between each of these operations, the support is conveyed from one station to another. I1 thus goes through a cart loading station before cooking and after cooking through a cart unloading station, then a station for removing the cooked object, a cleaning station, a turning station and finally a loading.

Many trips are therefore necessary. These displacements are called horizontal displacements, because they are carried out by conveyors generally moving the object and its support in a horizontal plane. During these horizontal displacements, the supports are subjected to numerous shocks and it often happens that one of them breaks.

 In addition, these numerous conveyors used to convey the objects and / or their supports require a large space.

 The object of the invention is therefore to propose a device making it possible to avoid a large number of horizontal manipulations in order to avoid impacts to the supports and also to save space.

To this end, the device for stacking and unstacking the workpiece supports that it offers
a lifting system intended to raise and lower a stack of workpiece supports,
a gripping device, placed above the lifting system, and
means allowing the loading and / or unloading of the parts from their supports and arranged between the lifting system and the gripping device.

 This device allows unstacking and stacking of the supports without the latter being set in motion in a horizontal plane. A method for stacking and unstacking supports with this device is described below as part of the invention. The supports, and therefore also the parts which they carry undergo here, with such a device, only little impact.

 In addition, this device allows a significant saving of space. Indeed, it does not require a lot of space in surface, and can be very compact in height. It suffices to have enough space for the vertical movement of the supports and for housing the gripping device. In case of lack of space, it is possible to find such a device which is compact.

 In a first embodiment, the device as described above is such that the lifting system comprises a jack embedded in the ground and having a bearing surface mounted at the end of a piston rod, said surface noticeably flush with the ground. Of course, other lifting systems are possible. A system with electric motor and rack or even worm can also be considered. I1 also exist lifting systems, known to those skilled in the art, which do not need to be embedded in the ground.

 The gripping device of the device according to the invention advantageously comprises two claws facing each other and which can either approach or move away from one another. This configuration allows a good grip of the supports.

 In a preferred embodiment, the loading and unloading means are constituted by a loading robot and an unloading robot, each comprising a gripper arm making it possible to grasp and rest a part.

The invention also provides a method of stacking and unstacking workpiece supports, which consists in
a) unload a support from the part it is carrying and / or load this support with a new part
b) raise the stack of supports until the newly loaded support is at the height of a gripper
c) grab this support using the gripping device
d) lower the stack of supports and bring the upper support to a position allowing it to be discharged and start again at step a) until all the supports in the stack are discharged and / or recharged.

 Such a method is adapted to the device according to the invention and allows stacking / unstacking without causing a great deal of shock to the workpiece carriers and to these.

 In any case, the invention will be clearly understood with the aid of the description which follows, with reference to the appended schematic drawing, representing by way of nonlimiting example an embodiment of a device according to the invention.

 Figures 1 to 5 show in elevation a destacking and stacking device according to the invention in various working positions.

 The stacking and unstacking device according to the invention shown in the drawing is used for handling supports 2. The latter carry, for example, dried or cooked tiles 4 and are placed in stacks on a tray 6, which is intended to conduct the tiles through a baking oven. The supports 2, each provided with a tile 4, are therefore stacked on the tray 6 before cooking and are unstacked after it.

 Each support 2 is formed by a substantially horizontal plate on which the corresponding tile 4 rests and by two vertical plates. The horizontal plate is fixed substantially at mid-height of the vertical plates and it has a width greater than that of the vertical plates, so that in side view (figures), the horizontal plate forms a protruding rim 8. Such supports 2 can be stacked by overlapping the vertical plates. A stack of supports, as shown in the figures, therefore presents, in side view, a series of flanges 8 placed at equal distance one above the other.

 The stack of supports 2 and the corresponding tray 6 are placed on a lifting system. The latter is disposed in a cavity 10 made in the ground. A jack 12, for example a hydraulic jack, is placed vertically in the cavity 10. I1 comprises a cylinder, a piston and a piston rod 14, connected on the one hand to the piston moving in the rod and on the other hand to a bearing surface 16 located outside the cylinder. In the rest position, the bearing surface 16 is substantially flush with the ground. The contact between the stack of supports 2 and its plate 6 on the one hand and the lifting system on the other hand, takes place at the level of the bearing surface 16.

 The device according to the invention described here comprises a robot for loading 4 "green" tiles, that is to say which are not yet cooked, and a robot for unloading 4 cooked tiles. The figures represent only one gripping arm 18 of each of these robots. These robots are not described in more detail here, because they are known to those skilled in the art and many different types of robots can be used here depending on the application and the desired rate.

 The loading and unloading robots are arranged so as to be able to unload a support 2 located on a stack placed on the lifting system.

 Above this lifting system, and at a higher altitude than that of the gripping arms 18 when they load or unload a support 2, is a gripping device 20. The latter comprises two arms at the end of each of which are located at least two claws 22 each intended to come under a rim 8 of a support 2 in order to be able to grip the latter. The gripping device 20 can thus carry a support 2 or even a whole stack of support s 2 lying on top of each other.

 The operation of this device according to the invention is described below with reference to the figures.

 In FIG. 1, an entire stack 24 of supports 2 is located on the plate 6, itself in contact with the bearing surface 16. Each support 2 is provided with a baked tile 4. In this example, the support 2 located at the top of the stack 24 is at a good height so that the gripping arms 18 of the robots can first of all remove the cooked tile 4 located on the upper support and then place a tile 4 there. "green".

 The stack 24 of supports 2 is then lifted vertically by the jack 12 (FIG. 2) until the claws 22 of the gripping device 20 are below the flanges 8 of the newly loaded support 2.

The claws 22 then close on this support 2 and grip it. This support 2 then constitutes the first element of a second stack 26.

 The jack 12 can then lower the stack 24 of supports, deprived of a support 2 located between the claws 22 of the gripping device 20 (Figure 3). The stack 24 does not descend to ground level, but slightly higher so that the support 2 now located at the top of the stack 24 can be discharged by the robot and its gripping arm 18.

 As shown in FIG. 3, the upper support 2 of the stack 24 is then freed from the baked tile 4 which it carries and the gripper arm 18 of the loading robot then comes to place a "green" tile 4 on this support 2. The stack 24 is then lifted until it comes into contact with the stack 26 located at the level of the gripping device 20. The claws 22 of the latter are then open and the jack 12 lifts all of the supports 2 so that the ledges 8 of the recently loaded support 2 are located just below the claws 22. These can then close and retain two supports 2. The stack 26 then expands while the stack 24 becomes smaller (Figure 4). The jack 12 can then lower the stack 24 to allow the discharge of the support 2 located at its top.

 FIG. 4 also shows, using double arrows, the various movements of the elements used to unstack and stack.

 These operations are resumed until the last support 2 is provided with a "green" tile 4, as shown in FIG. 5. The jack can then mount the last support 2 until it is in contact with the stack 26 of supports. The gripping device 20 can then release the stack 26. All of the supports 2 therefore carry a "green" tile 4.

 Depending on the type of gripping device 20 and as required, the stack of supports 2 can then either be taken up by the gripping device 20 if the latter can move to deposit the supports s 2, for example on a carriage (not shown), or still stay on the tray 6 and go down again to be then brought into a baking oven.

 It goes without saying that the invention is not limited to the embodiment described above by way of nonlimiting example; on the contrary, it embraces all its variants.

 Thus, for example, the lifting device could comprise not a jack but other means allowing the lifting, such as for example a motor and a rack.

 Similarly, it is not compulsory to have a loading robot and an unloading robot. The device can only be used to load or unload the media. Even in the case of loading and unloading, there are robots or other handling devices which, with a single gripping arm, can perform these two tasks.

 The description is made with reference to a tile production line. The invention could of course relate to another industry in which parts are placed on a support to undergo various stages of a manufacturing process.

Claims (5)

 1. Device for stacking and unstacking the supports (2) of parts (4), characterized in that it comprises  a lifting system (12) intended to raise and lower a stack (24) of supports (2) for parts,  a gripping device (20), placed above the lifting system (12), and  means (18) allowing the loading and / or unloading of the parts (4) from their supports (2) and arranged between the lifting system (12) and the gripping device (18).  2. Device according to claim 1, characterized in that the lifting system comprises a jack (12) embedded in the ground and having a bearing surface (16) mounted at the end of a piston rod (14), said surface (16) substantially flush with the ground.  3. Device according to claim 1 or 2, characterized in that the gripping device (20) has two claws (22) facing each other and which can either approach or move away from each other.  4. Device according to one of claims 1 to 3, characterized in that the loading and unloading means consist of a loading robot and an unloading robot, each comprising a gripper arm (18) for gripping and install a part (4).  5. Method for stacking and unstacking supports (2) of parts, characterized in that it consists of  a) unload a support (2) from the part (4) which it carries and / or load this support (2) with a new part (4)  b) raise the stack (24) of supports (2) until the newly loaded support (2) is at the height of a gripping device (20)  c) grasp this support (2) using the gripping device (20)  d) lower the stack (24) of supports and bring the upper support to a position allowing it to be discharged and repeat in step a) until all the supports (2) of the stack (24) are discharged and / or recharged.