Order picking system

Abstract

An order picking system includes an automatic guided trolley for picking objects for an order in at least one shelving and having at least two running wheels and gear wheel supports cooperating with two pairs of uprights so as to allow the trolley to rise along the uprights. A stretched roller chain is fixed on each of the uprights, the chain extending substantially parallel to the longitudinal axis of the upright to which it is fixed to receive a tooth of the gear wheel cooperating with the upright to which it is fixed. Two adjacent rollers of the chain are spaced apart by the pitch value of the gear wheel. Each movable support has a securing element with one of the four uprights to maintain a predetermined distance between the axis of the gear wheel mounted on the movable support and the chain receiving the teeth of the gear wheel.

Claims

1. An order picking system comprising: first and second pairs of uprights each pair attached to two separate shelvings delineating a centre aisle; an automatic guided vehicle having a chassis, at least two running wheels for picking up objects for an order in at least one of said shelvings, and a motorised climbing module, which cooperates with said uprights so as to allow said vehicle to rise along said uprights, said climbing module comprising first, second, third and fourth gear wheels of substantially parallel axes, each gear wheel cooperating with one of the uprights, the axes of the gear wheels being substantially orthogonal to axes of the running wheels, each of the gear wheels being mounted on a support that can be moved relative to the chassis of said vehicle between: a spaced-apart position in which at least a portion of said gear wheel mounted on said support protrudes laterally out of alignment with said chassis; a retracted position, in which the gear wheel mounted on said support is facing said chassis; a substantially stretched roller chain fixed on each of said uprights, said chain extending substantially parallel to a longitudinal axis of the upright to which it is fixed and receiving at least one tooth of the gear wheel cooperating with the upright to which it is fixed, first and second adjacent rollers of said chain being substantially spaced apart by a pitch value of said gear wheel, and wherein each movable support is secured with one of said uprights so as to maintain a predetermined distance between the axis of the gear wheel mounted on said movable support and the chain receiving the teeth of said gear wheel.

2. The order picking system according claim 1, wherein said movable supports are mounted substantially at first, second, third and fourth ends of the chassis of said vehicle.

3. The order picking system according to claim 1, wherein at least one of said uprights comprises a longitudinal groove adapted to receive said chain.

4. The order picking system according to claim 1, wherein at least one of said uprights is an omega profiled rail.

5. The order picking system according to claim 1, wherein said vehicle comprises a gripper configured to grip an object storage bin.

6. The order picking system according to claim 1, further comprising a brake for braking said climbing module.

7. The order picking system according to further comprising first and second independent motors each driving one of pair of the gear wheels.

8. The order picking system according to claim 1, further comprising a securing mechanism for securing each movable support to one of said four uprights, which comprises at least one support wheel and a counter-wheel of axes parallel to the axis of the gear wheel mounted on the movable support, suitable for rolling on one of said uprights.

9. The order picking system according to claim 8, wherein at least one of said uprights comprises at least one aisle extending substantially perpendicular to the longitudinal axis of said upright, said support wheel bearing upon one side of said aisle and said counter-wheel bearing upon an opposite side of said aisle.

10. The order picking system according to claim 1, wherein each of said chains is attached substantially to both ends of one of said uprights.

11. The order picking system according to claim 10, further comprising an adjustment mechanism, which adjusts a position at which at least one of said chains is fixed substantially at one end of one of said uprights, along the longitudinal axis of said upright, allowing said chain to be stretched.

12. The order picking system according to claim 11, wherein said adjusting mechanism comprises a spring.

Description

5. LIST OF FIGURES

(1) Other features and advantages of the invention will appear more clearly on reading the following description of an embodiment of the invention, given as a simple illustrative and non-limiting example, and the appended drawings among which:

(2) FIG. 1 is a schematic view, in perspective of a warehouse equipped with an exemplary embodiment of an order picking system according to the invention;

(3) FIG. 2 is a schematic perspective representation of an automatic guided vehicle used in the warehouse illustrated with reference to FIG. 1;

(4) FIG. 3 is a top view in which the vehicle presented in reference to FIG. 2 climbs against two parallel shelvings;

(5) FIG. 4 is a detailed view of the base of a shelving upright shown with reference to FIG. 1;

(6) FIG. 5 is a detailed cross-sectional view of a climbing module of the vehicle presented with reference to FIG. 2;

(7) FIG. 6 is a top view of a vehicle climbing module that cooperates with an upright of the shelvings shown in reference to FIG. 1;

(8) FIG. 7 is a detailed view of the drive system for the climbing modules of the vehicle presented with reference to FIG. 2;

(9) FIG. 8 is a detailed view of the device for compensating the gap between the two profiled rails fitted to a climbing module of the vehicle presented in reference to FIG. 2.

6. DETAILED DESCRIPTION OF THE INVENTION

(10) 6.1. First Exemplary Embodiment of the Invention

(11) FIG. 1 shows a warehouse 1 for storing products for shipment. This warehouse is divided into a storage area 10 and an order picking area 11.

(12) The picking area 11 comprises order picking stations 12 on which operators 13 prepare packages 14 with the products of an order.

(13) The storage area 10 is organised into shelvings 100 with shelves on several levels 101 supported by uprights 105, shelves on which are stored bins 102 that contain the stored products or articles.

(14) A fleet of automatic guided vehicles 103 ensures the transport of the bins 102 between the storage area 10 and the order picking stations 12.

(15) Each robot 103 receives the location information of the bin 102 containing the item to be picked up, to complete an order processed by one of the operators 13. The robot 103 goes to the location where the bin 102 is located and takes it out of the shelve 101 of the shelving 100 specified by the location information received. Then, the robot 103 transports the bin 102 from the shelving 100 via aisles 104 to the order picking station 12. The operator 13 only has to pick the quantity of items ordered and pack them. The robot 103 then returns the bin 102 to its location in the storage area 10.

(16) The shelvings 100 are identical and arranged in parallel. The space between two shelvings 100 forms a span 104 which serves as a centre aisle for robots 103.

(17) FIG. 2 shows a robot 103 consisting of a chassis 200 that is carried by two idle wheels 201 and towed by two drive wheels 202 powered by motors 203 which are independent from each other. Thus, on a substantially flat and horizontal ground, the self-guided vehicle 103 can follow straight, curved paths and revolves around itself depending on the rotation control of the motors 203.

(18) To climb shelvings 100, the chassis of the robot 103 is equipped, approximately at the four ends of the chassis, with a retractable climbing module 204. The extension and retraction of these climbing modules 204 is powered by a motor (not shown) that translates two lateral telescopic forks 205 carrying the climbing modules 204 between a spaced apart position and a retracted position.

(19) Thus, the robot 103 can be mounted on uprights of two parallel shelvings 100 facing each other, distributing its weight over the four uprights 105.

(20) Each side telescopic fork 205 consists of a control rod 206, a deflection rod 207 and two sliding arms 210, each carrying a climbing module 204.

(21) For each telescopic fork 205, the deflection rod 207 is held in its centre by a pivot link using a first so-called central axis 208 with the distal end of the substantially perpendicular control rod 206. In addition, the deflection rod 207 at each distal end is pivotally connected by a second axis 209 to a sliding arm 210.

(22) Thanks to these pivot links, the robot tolerates a variation in the distance between the uprights 105 of the shelvings 100 to be climbed. These pivot links also make it possible to correct a deviation in parallelism between the longitudinal axis of the robot 103 and each pair of uprights 105. Indeed, the successive contact of the climbing modules of the same fork, followed by a simultaneous thrust, allows the position deviation to be corrected. This mechanism is supplemented by a gap compensation device between the uprights 105 (not shown in FIG. 2), which will be described in more detail below in FIG. 8.

(23) Each telescopic fork 205 is also equipped with a drive system for two climbing modules 204 located on the same side of the chassis. This drive system consists of a drive shaft 211 with a driven pulley 212 attached to it, and is connected at each end to a gear wheel of a climbing module 204 (visible in the detail view in FIG. 4).

(24) The driven pulley 212 is driven by a toothed belt 213 which transmits the movement of a driving pulley 214 driven by a climbing motor 215. In addition, the transmission shaft 211 is equipped with a cardan shaft 216 with two seals that allows a lateral position deviation between the two climbing modules 204 of the telescopic fork 205, which allows a constant velocity transmission to be achieved.

(25) Each climbing motor 215 is independently controlled by a motor shaft position control module (not shown in FIG. 2), to ensure that the robot 103 remains horizontal and the load does not fall. Thus, the control module adapts the speed of each motor 215 to compensate for the deviation between the rollers of the chains fixed on each upright 105, whose length may vary during their manufacture, taking into account manufacturing tolerances.

(26) It should be noted that, on 10 to 12 meters long uprights 105, equipped with chains of the same type, the position difference between the end rollers of two chains can reach 20 mm.

(27) FIG. 3 shows a robot 103 in top view, while climbing two shelvings 100 using the four climbing modules 204 which cooperate with two pairs of uprights 105 of the two substantially parallel shelvings 100 which delineate the aisle 104.

(28) The robot 103 is equipped with a system for translating the telescopic forks 205 between a spaced apart position and a retracted position. This translation system consists of two pulleys and a toothed belt (not shown in FIG. 3) attached to the chassis in the median transverse plane of the robot 103. In addition, on each opposite strand of this toothed belt is fixed the proximal end of one of the two control rods 206. To extend or retract the climbing module 204, the driving pulley, driven by a fork control motor 205 (not shown in FIG. 3), drives the toothed belt that controls the translation of the climbing module 204.

(29) It is therefore the direction of rotation of the stepper motor controlled by a module for controlling the position of the shaft of the fork control motor 205 (not shown in FIG. 3) that allows the climbing modules 204 to be moved between the retracted position for ground travel and the spaced apart position for climbing on the shelvings.

(30) Thus, the climbing modules 204 extend or retract simultaneously on both sides or lateral sides of the robot 103. In addition, if the climbing modules 204 of a telescopic fork 205 come into contact with the uprights 105 on either side of the aisle 104 before the other, due to a centring deviation of the robot 103 in the aisle 104, the pressure exerted by the telescopic fork 205 will redirect the robot 103 between the uprights 105 on either side of aisle 104.

(31) FIGS. 4 to 6 show in more detail the climbing module 204 and the upright 105 to which an Omega () profiled rail 410 is attached. As shown in FIG. 4, each climbing module 204 includes a base 400 which supports a gear wheel 401, a centring wheel 402, two support wheels 403 and two counter-wheels 404.

(32) In addition, it should be noted that the base of the profiled rail 410 is held in a support 411 which includes a groove 412 on the front to guide the centring wheel 402 of the climbing module 204 when it is extended, in order to centre and thus guarantee the position of the climbing module in relation to the profiled rail 410.

(33) In addition, the profiled rail 410 is at its base reduced to a U-shaped profile forming a clearance 414 in this section to allow the two counter-wheels 404 of the climbing module 204 to pass behind the aisles 413. This centring wheel 402 therefore guarantees the relative position of the gear wheel 401, the two support wheels 403 and the two counter-wheels 404 with respect to the Q profiled rail 410.

(34) In FIG. 5, which is a cross-sectional view of the retractable climbing module 204 in the spaced apart position, the 401 gear wheel cooperates with the links of an ordinary roller chain 500, held tight at the bottom of the Omega profiled rail 410. For this purpose, the first end of the roller chain 500 is bolted to a hooking point (not shown in the figures) at the base of the profiled rail 410 used as the origin point for climbing or moving according to axis Y. The second end of the chain is substantially secured to the top of the profiled rail 410 by a second bolt. The position of this second bolt is adjustable to correct the chain tension 500 whose length increases with the operating time.

(35) As can be seen in more detail from above in FIG. 6, the profiled rail 410 has a groove 600 delineated by a bottom 601 which is substantially perpendicular to two flanks 602 higher than the diameter of a counter-wheel 404 and parallel to each other.

(36) In addition, each side wall 602 is extended by an aisle 413 which extends substantially perpendicularly in a transverse orientation from the flank 602 to the outside of the profiled rail 410. In addition, each flank 602 has a greater width than the width of the support wheels 403 and the counter-wheels 404, thus forming a front support face 603 or a rear support face 604 for these wheels 403, 404.

(37) In FIG. 6, the climbing module 204 is shown in a spaced apart position where the gear wheel 401 is engaged on the chain 500. In this climbing configuration, each wheel 403 is supported on the front face 603 of a first aisle 413 while each counter-wheel 404 is supported on the rear face 604 of a second aisle 413 of the Q profiled rail 410. It can therefore be seen that the front 603 and rear 604 faces of an aisle 413 form a runway pinched by the assembly 610 formed by the support wheel 403 and the counter-wheels 404. Thus, each assembly 610 guides and maintains the relative position of the climbing module 204 with respect to the profiled rail 410 and therefore that of the rotation axis of the gear wheel 401 with respect to that of the chain 500. The grippers 610 compensate for the low winding arc of the chain 500 on the gear wheel 401, well below the usual 90 minimum limit, by ensuring that the gear wheel 401 is constantly engaged with the chain 500.

(38) To climb up the shelvings 401, the robot 103, after aligning itself with the uprights 105, deploys the four gear wheels 401, which allows the gear wheels 401 to engage with the chains 500 present in the profiled rails 410 of the four uprights 105. The rotation of the gear wheels 401 then allows the robot 103 to move vertically, which can climb up or down along the uprights 105.

(39) To initiate climbing, the shaft position control module of the fork extension control motor 205 controls the extension of the climbing modules 204 so that the support wheels 403 exert pressure on the front face 603 of the aisles 413 of the profiled rails 410 until the counter-wheels 404 have crossed the clearance zone 414 to contact the rear face 604 on the reverse side of the aisles 413.

(40) Thus, each gear wheel 401 remains engaged with the chain 500 due to the pressure exerted by the support wheels 403 on the profiled rail 410, which prevents the chain from coming off.

(41) When clearance zone 414 is crossed, the motor shaft position control module reverses the direction of rotation of the fork control motor 205 by a fraction of a revolution smaller than the functional clearance of the transmission that must be caught up with when the direction of rotation of the motor is reversed in order to drive the belt in the opposite direction. The transverse movement of the forks 205 is then free in the interval of the functional clearance. In this way, the distance between two climbing modules 204 in the same transverse plane can vary slightly to compensate for variations in distances between two uprights 105 facing each other on either side of aisle 104. Each set 610 of each climbing module 204, then guarantees that each gear wheel 401 remains engaged with the chain 500 facing each other.

(42) During descent, the motor shaft position control module instructs the fork control motor 205 to apply pressure to the profiled rails 410 near and inside the clearance area 414.

(43) As shown in FIG. 7, which is a detailed view of the drive system 700 of the two climbing modules 204 of each telescopic fork 205, the drive system 700 also comprises a clutch system 701 of the belt 213 with the driving pulley 214 and the driven pulley 212, using a tensioner roller 702. This tensioner roller 702 is mounted movably in a bracket above the toothed belt 213 to support the outer part of the upper belt 703. This tensioning roller 702 can be moved between three positions: a disengaged position in which the driving pulley 214 and the driven pulley 212 are decoupled, because the tensioner roller 702 is not in contact, therefore does not tension the belt 213; an engaged position corresponding to nominal operation, in which the roller 702 tensions the belt 213 and ensures proper transmission of torque from the motor 215 to the transmission shaft 211; and a safety position in the event of a breakage of the toothed belt 213, which causes the tensioner roller 702 to automatically fall off, coming into contact with the driven pulley 212 and blocking it by friction.

(44) During normal operation, the roller 702 is in the engaged position to transmit the motor torque to the gear wheels 401.

(45) If the robot 103 is blocked during an escalation, such as by a broken belt 213, maintenance personnel can then disengage the motor by manually disengaging the tension roller 702 in order to lower the robot 103.

(46) FIG. 8 shows in detail a compensation device 800 for the distance between the two profiled rails 410 of a pair of uprights 105 of a shelving 100, which is inserted between the end of the sliding arm 210 and the base 400 of the climbing module 204. Each telescopic fork 205 is equipped with a single compensation device 800 on the sliding arm 210 opposite the drive system (not shown in FIG. 8). The compensation device 800 consists of a slide 801 formed by a bearing connected to the sliding arm 210 and a slide 802 formed by an axis integral with the base 400, both sliding relative to each other over a length of one centimetre according to the longitudinal orientation of the robot 103.

(47) Thanks to this articulation of the compensation device, the robot 103 tolerates a variation of +/5 mm between the two profiled rails 410 of each pair of uprights 105.

(48) 6.2. Other Optional Features and Advantages of the Invention

(49) In embodiment variants of the invention detailed above, the following can also be provided: fitting the automatic guided vehicle with two driving wheels centred on it, while two idle wheels are arranged on the periphery and ensure the stability of the vehicle. This geometry of the running gear is then coupled with a balance system that guarantees isostatism and distributes the weight of the robot and its load over all four wheels, regardless of ground imperfections; a braking device for the vehicle during descents; an automatic lowering of the vehicle in the event of an anomaly, for example in the event of a loss of electrical power. In this situation, the brakes are released, and the rate of descent to the ground is limited by exerting a magnetic field on the motor(s) of the climbing equipment, so as to create a viscous brake; a location at altitude, by recognising the shelvings that support bins, by recognising bins for example using an RFID chip (Radio Frequency Identification); fitting the automatic guided vehicle with a fork or telescopic shovel to lift, move and lower a bin or an object; fitting the automatic guided vehicle with telescopic side arms, or a telescopic fork with a finger at the end of which is mounted, for pushing or pulling bins, by sliding them onto their shelving; fitting the vehicle with a bin weighing scale to carry out an inventory of the contents of the bins; installing the uprights in the immediate vicinity of the shelvings, to allow the robot to move up and down along the shelvings, these uprights can be fixed to the ground or to a shelving; providing a profiled upright with a single side aisle associated with a climbing module that has a single support wheel and a single counter-wheel capable of cooperating with the single side aisle; rail-shaped profiled uprights whose bottom and flanks form a dovetail-shaped female footprint; fitting each climbing module with two parallel gear wheels and each upright with a double chain; providing at one end of the uprights means for adjusting the chain tension using a spring; uprights which have a groove in which to accommodate a chain and aisles for supporting the wheels of the climbing modules, on the outside of the uprights in relation to the shelving; providing for each climbing module at least one longitudinal guide wheel with an axis perpendicular to the gear wheel and capable of rolling on one flank of the profiled rail so as to substantially guarantee the centring of the gear wheel with respect to the chain of the profiled rail; a slide linked to the base and a ram 802 fixed to the sliding arm; a securing mechanisms including skids intended to slide on the uprights.

(50) The examples of order picking systems described above can be used in different types of industrial environments, for example in an order picking supply centre or in a supply chain for spare parts or components in a production chain.

(51) An exemplary embodiment of the invention therefore particularly aims to overcome the disadvantages of the state of the art mentioned above.

(52) An exemplary embodiment of the invention aims to provide an order-picking technique that limits human intervention and is simple to implement.

(53) An exemplary embodiment of the invention provides an inexpensive order-picking technique.

(54) An exemplary embodiment of the invention provides a low-noise order-picking technique.

(55) An exemplary embodiment of the invention provides an order-picking technique that can be easily adapted to changes in the storage area.

(56) An exemplary embodiment of the invention provides a picking technique that is compatible with a dense storage area.

(57) An exemplary embodiment of proposes such a technique that allows the use of shelving of different heights and/or orientations in the same warehouse.

(58) An exemplary embodiment of the invention also provides an order-picking technique while using existing shelvings.

(59) Another object of an exemplary embodiment of the invention is to provide an order-picking technique that is safe for operators.

(60) Although the present disclosure has been described with reference to one or more examples, workers skilled in the art will recognize that changes may be made in form and detail without departing from the scope of the disclosure and/or the appended claims.