JP2010058978A - Palletizing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a palletizing device with a simple composition capable of flexibly palletizing at high speed by preventing interference between workpieces during palletizing and generation of clearances between the palletized workpieces, even if there is variation in the dimensions of the workpieces and pallets. <P>SOLUTION: The device 1 includes a hand part 2 for holding a workpiece, an arm part 3 for moving the hand part 2, a metering part 5 for obtaining the position information of the loaded workpiece, a storage part 6 for storing the information, and a control part 10 for controlling the movements of the respective parts. When the hand part 2 holding the workpiece is moved to load the workpiece on a pallet, the control part 10 obtains the loading position of the workpiece by the metering part 5 and makes the storage part 6 store the loading position. When the next workpiece is loaded on a pallet, the control part determines the scheduled loading position of the workpiece based on the loading position stored in the storage part 6. As the loading position of the already-loaded workpiece is used as the reference, the device can deal with the variation in the dimensions of workpieces and pallets and can prevent the interference and the generation of clearances. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a palletizing apparatus that sequentially conveys workpieces and aligns and loads them on a pallet.

  Conventionally, a so-called palletizing apparatus, that is, a palletizing apparatus for loading a work on a pallet for the transportation and handling of the work, has been actively used in production factories, distribution transportation industries, and the like. When such a palletizing apparatus is automatically operated, it is desirable to align and load the workpieces on the pallet so that the workpieces are prevented from interfering with each other and there is no gap between them. Therefore, the workpiece is placed at the position on the pallet calculated from the target position of the workpiece calculated in advance on the pallet and the pressing movement amount of the workpiece, and then the workpiece is placed on the palletized workpiece. An apparatus that moves so as to press a workpiece is known (for example, see Patent Document 1).

  In addition, the palletizing device grips the workpiece without misalignment and loads it on the pallet, so that the workpiece posture and position are corrected before palletizing in order to prevent mutual interference and gaps on the pallet. A palletizing apparatus provided with a positioning station for this purpose is known (see, for example, Patent Document 2).

Japanese Patent No. 2549139 (Japanese Patent Laid-Open No. 1-222279) JP-A-8-85627

  However, the palletizing apparatus as shown in Patent Document 1 and Patent Document 2 described above has the following problems. That is, the palletizing apparatus of Patent Document 1 is unclear because it does not disclose how to calculate the target position of the workpiece on the pallet. If the target position is calculated from the default pallet position and default workpiece dimensions, problems such as mutual interference between workpieces and gaps between workpieces may occur due to the accumulation of workpiece dimensional variations. Become. Further, although the palletizing device of Patent Document 2 is effective in gripping the workpiece without positional deviation, it cannot cope with the dimensional variation of the workpiece, and there is a problem of processing time generation in the positioning station.

  The present invention solves the above problems, and prevents the occurrence of interference between palletized workpieces and gaps between palletized workpieces even when there are dimensional variations in workpieces and pallets with a simple configuration. An object of the present invention is to provide a palletizing device that can be palletized flexibly and at high speed.

  In order to achieve the above object, the invention of claim 1 is a palletizing device that sequentially conveys a workpiece from its supply location and aligns and loads the workpiece on a pallet, the hand portion gripping the workpiece, and the hand portion. An arm unit for moving the workpiece, a measuring unit for acquiring information on the loading position of the workpiece on the pallet, a storage unit for storing the loading position, and a control unit for controlling the operation of each unit, The control unit acquires the loading position of the workpiece by the measuring unit when the workpiece is loaded on the pallet by moving the hand unit that grips the workpiece by the arm unit, and stores the loading position in the storage unit. When the work is loaded on the pallet, the work loading planned position is determined based on the loading position stored in the storage unit.

  The invention of claim 2 is the palletizing apparatus according to claim 1, further comprising a workpiece measuring unit for measuring workpiece dimensions, and when the workpieces that can be loaded in multiple stages are loaded in multiple stages on the pallet, Control the hand unit so that the workpiece is loaded on the upper stage when the workpiece dimension measured by the workpiece measuring unit is larger than the dimension of the unloaded part of the pallet in the stage where loading is scheduled It is.

  According to a third aspect of the present invention, in the palletizing apparatus according to the second aspect, when the workpiece size is larger than the size of the unloaded portion, a workpiece having a size smaller than the size of the unloaded portion is placed on the unloaded portion. Select and load.

  According to a fourth aspect of the present invention, in the palletizing device according to the first or second aspect, the hand portion has at least two types of long and short claws for gripping a workpiece, and the long claws are arranged from the planned loading position. It is used to place the work on a pallet with a predetermined clearance and pull out a short claw, and then press the work to close the clearance.

  According to a fifth aspect of the present invention, in the palletizing apparatus according to the fourth aspect, the control unit measures a reaction force acting on a nail that presses the workpiece with a stress sensor when the clearance is reduced, and a reaction force equal to or greater than a predetermined value. The position where the force is measured is used as the workpiece loading position.

  According to a sixth aspect of the present invention, in the palletizing apparatus according to the fourth or fifth aspect, the work is a rectangular parallelepiped whose bottom shape upon loading onto the pallet differs depending on the loading posture, and the control unit is configured to load the pallet unloaded. The bottom surface of the workpiece at the time of loading is selected according to the dimensions of the part.

  A seventh aspect of the present invention is the palletizing apparatus according to any one of the first to sixth aspects, wherein the pallet has workpiece fall prevention members at both ends of the workpiece alignment direction, and the control portion is the workpiece. The last workpiece aligned near the rear end side of the tipping prevention member is lowered from above the planned loading position while being tilted toward the workpiece loaded earlier, and the upper rear of the workpiece loaded earlier The hand portion is controlled so that the workpiece is placed upright by being rotated around the end corner portion and loaded on the pallet.

  The invention of claim 8 is the palletizing device according to any one of claims 1 to 6, wherein the pallet has workpiece fall prevention members at both ends of the workpiece alignment direction, and the workpiece fall prevention member A guide plate for smoothly loading the last workpiece aligned near the end side is provided on the pallet side.

  According to a ninth aspect of the present invention, in the palletizing apparatus according to the first aspect, the control unit places the work at a position returned by a predetermined distance after moving the work along the work alignment direction to the planned loading position. Thus, the hand unit is controlled.

  A tenth aspect of the present invention is the palletizing apparatus according to any one of the first to ninth aspects, wherein the control unit moves the workpiece along the workpiece alignment direction on the pallet. The reaction force acting on the nail on the side that pushes the workpiece provided for is measured by a stress sensor, the position where the reaction force greater than a predetermined value is measured is set as the movement completion position, and the reaction for judging the completion position is determined. The predetermined value for the force is set according to the strength of the workpiece.

  The invention of claim 11 is the palletizing apparatus according to any one of claims 1 to 10, further comprising a workpiece measuring unit for measuring a workpiece dimension, wherein the control unit is measured by the workpiece measuring unit. By comparing the measured workpiece dimensions with the standard workpiece dimensions stored in advance, it is determined whether the workpiece types are different.

  According to the first aspect of the present invention, the actual workpiece loading position is grasped and the loading position information is fed back to the loading of the next workpiece. It is possible to cope with dimensional variations of workpieces and pallets, and to palletize flexibly and at high speed by preventing interference between workpieces during palletizing and generation of gaps between palletized workpieces.

  According to the invention of claim 2, since it is possible to determine whether loading is possible in advance and to select and load a workpiece having a loadable size, even if there is a variation in the size of the workpiece, Palletizing can be performed without generating an unloaded space on the pallet, and loading errors can be eliminated. In addition, since the device responds autonomously and flexibly, it can be handled at high speed without the device getting stuck or calling a worker.

  According to the third aspect of the present invention, it is possible to flexibly cope with dimensional variations of workpieces, palletizing without generating an unloaded space on the pallet, and eliminating loading mistakes.

  According to invention of Claim 4, a short nail | claw can be escaped and a workpiece | work can be moved so that a short nail | claw may not be pinched | interposed between workpiece | work, and contact | adherence alignment of workpieces is attained. In addition, when opening and closing the nail, there is no need to consider securing clearance for opening and closing.

  According to the invention of claim 5, the workpieces can be appropriately pushed and aligned without being influenced by the variation in the clearance. Moreover, it can prevent that a workpiece | work and a hand part are damaged by the excessive force added to the workpiece | work.

  According to the sixth aspect of the present invention, it is possible to flexibly deal with dimensional variations of individual workpieces and pallets, and to load the workpieces on the pallet appropriately, that is, without generating a gap.

  According to invention of Claim 7, when the clearance for workpiece | work loading is small, it can avoid loading with the corner | angular part of a workpiece | work, and can be loaded reliably.

  According to the eighth aspect of the present invention, when the clearance for loading the workpiece is small, the workpiece can be reliably loaded while avoiding interference between the workpiece and the corner portion of the workpiece fall prevention member.

  According to the invention of claim 9, in the case of multi-stacking, the workpiece can be placed while avoiding the protrusion of the corner portion of the lower workpiece in the vicinity of the lower portion of the front workpiece, which is generated due to variations in workpiece dimensions, etc. It is possible to prevent problems such as being placed and falling. Since the gap generated by returning the predetermined distance can be sequentially filled by the filling operation by the next workpiece, even if there is a dimensional variation in the workpiece or pallet, it can be densely stacked.

  According to the tenth aspect of the present invention, the workpiece and the hand portion can be appropriately moved without being damaged, and the gap between the workpieces can be prevented from being generated and densely loaded.

  According to the eleventh aspect of the present invention, it is possible to prevent different types of workpieces from being mixedly loaded on one pallet since the difference between the types of workpieces is determined.

1 is a perspective view of a palletizing apparatus according to a first embodiment of the present invention. The block block diagram of an apparatus same as the above. (A) is a perspective view of the hand part of an apparatus same as the above, (b) is the sectional view on the AA line of (a). The perspective view which shows the movement of the workpiece | work by an apparatus same as the above. The side view which shows the movement of the workpiece | work by an apparatus same as the above. It is a perspective view which shows the pallet loading of the workpiece | work by the apparatus same as the above, (a) is a perspective view of the state which took out the workpiece | work from the conveyor, (b) is a perspective view of the state which drops a workpiece | work on a pallet, (c) is A perspective view of the hand part with the short claws pulled out, (d) is a perspective view of the work parts aligned with the long claws of the hand part, and (e) is a perspective view of the hand parts with the workpieces loaded and pulled out. Figure. (A) is a side view showing the first workpiece just above the pallet to be aligned by the same apparatus together with its trajectory, and (b) is a side view showing the second workpiece together with its trajectory. 7 (a) and 7 (b) show a modified example, in which (a) is a side view showing the first workpiece immediately above the pallet to be aligned by the same apparatus together with its trajectory, and (b) is also the second workpiece together with its trajectory. FIG. (A) is a perspective view of a hand part of a palletizing device according to a second embodiment and a workpiece on a conveyor, (b) is a perspective view showing a state in which the workpiece is placed on a pallet by the hand unit. (A) is a perspective view of a hand part of a palletizing device according to a third embodiment and a work on a conveyor, (b) is a perspective view of a state in which the work is horizontally held by the hand part, and (c) is the same hand. The perspective view of the state which rotated the workpiece | work hold | gripped by the part. It is a perspective view which shows the pallet loading of the workpiece | work by the apparatus same as the above, (a) is a perspective view of the state which drops a workpiece | work on a pallet, (b) is a perspective view of the state which lowered the workpiece, (c) is a hand part The perspective view of the state which pulled out the short nail | claw of (2), (d) is the perspective view of the state which aligned the workpiece | work with the long nail | claw of a hand part, (e) is the perspective view of the state which the workpiece | work loading ended and the hand part was extracted. (A) is a perspective view of the hand part of the palletizing apparatus which concerns on 4th Embodiment, (b) is a perspective view of the state which hold | gripped the workpiece | work with the hand part and took out from the conveyor. It is a perspective view which shows in steps the pallet loading of the workpiece | work by an apparatus same as the above, (a) is a perspective view of the state which drops a workpiece | work on a pallet, (b) is a perspective view of the state which lowered | hung the workpiece | work and pulled out the short nail of the hand part FIG. 4C is a perspective view of a state in which the workpieces are aligned with the long claws of the hand unit, and FIG. 5D is a perspective view of the state in which the hand unit is pulled out after the workpiece is loaded. It is a side view which shows in steps the loading of the workpiece | work on the pallet by the palletizing apparatus which concerns on 5th Embodiment, (a) is a side view of the state which inclines and lowers a workpiece | work from pallet upper direction, (b) is an already loaded state. The side view which shows a mode that a workpiece | work is rotated beside a workpiece | work, (c) is a side view in the state which lowered | hung the erecting workpiece | work further, (d) is a side view in the state which finished the workpiece | work loading. The side view explaining the positional relationship between the workpieces in the state shown in FIG. The side view which shows the loading of the workpiece | work to the pallet by the palletizing apparatus which concerns on 6th Embodiment. It is a side view which shows loading of the workpiece | work on the pallet by the palletizing apparatus which concerns on 7th Embodiment, (a) is a side view before loading, (b) is a side view after loading. The side view of the loaded workpiece | work and pallet which shows the other example of the workpiece | work loading by an apparatus same as the above. It is a side view which shows loading to the pallet of the workpiece | work by the palletizing apparatus which concerns on 8th Embodiment, (a) is a side view before loading, (b) is a side view after loading. It is a side view which shows the example of the attitude | position of the workpiece | work when gripping the workpiece | work by the hand part of the palletizing apparatus which concerns on 9th Embodiment, and mounting on a pallet, (a) is a side view when a workpiece | work is not rotated, (B) is a side view when the workpiece is rotated by 90 °, (c) is a side view when the workpiece is rotated by 180 °, and (d) is a side view when the workpiece is rotated by 270 °. The side view of the workpiece | work and pallet which were arranged and loaded by the apparatus same as the above. (A) is a side view explaining the loading state of the workpieces placed in the gap in FIG. 21, and (b) is a side view of other workpieces. The flowchart of the process by the palletizing apparatus which concerns on 10th Embodiment. (A)-(d) is a side view which shows the workpiece | work loading procedure by an apparatus same as the above in time series, (a1) (b1) (d1) shows the example of a malfunction corresponding to (a) (b) (d). Side view. (A) (b) (c) is a side view which shows the pushing operation of the workpiece | work by the apparatus same as the above in time series. (A)-(e) is a perspective view which shows the loading procedure of the workpiece | work by the apparatus same as the above in time series. The relationship figure of the pushing amount and reaction force of the long nail which concern on the usage method of the stress sensor in 1st, 3rd, 4th, 10th embodiment. The block block diagram of the palletizing apparatus which concerns on 11th Embodiment. (A) is a flowchart of the process by an apparatus same as the above, (b) is a flowchart of the modification.

  Hereinafter, a palletizing apparatus according to an embodiment of the present invention will be described with reference to the drawings.

(First embodiment)
FIG. 1 shows the external appearance of the palletizing apparatus 1 according to the first embodiment, FIG. 2 shows the block configuration of the apparatus, and FIGS. 3A and 3B show the structure of the hand unit 2 of the apparatus. The configuration of the apparatus will be described with reference to these drawings, and then the operation of the apparatus will be described in detail with reference to FIGS. 1 and 2 have the same basic apparatus configuration in the other embodiments, and are therefore referred to as needed in other embodiments.

  The palletizing apparatus 1 is an apparatus that sequentially transports workpieces W from a supply place, and loads and aligns them on a portable pallet 7 previously set at a predetermined position, that is, a palletizing apparatus. The workpiece W is a long box, for example, a cardboard box, and is supplied by the conveyor 9 and positioned by the stopper 91 to be stationary. The palletizing apparatus 1 grips and conveys both ends of the workpiece W positioned on the conveyor 9 in the longitudinal direction. Therefore, the palletizing apparatus 1 has a pair of configurations on the left and right sides toward the conveyor 9. The pallet 7 is arranged on the floor surface on the center line of the palletizing apparatus 1 configured as a pair of left and right.

  The palletizing device 1 includes a hand unit 2 that grips a workpiece W, an arm unit 3 that holds and moves the hand unit 2 via a rotating unit 23, a transport unit 4 that travels and moves the arm unit 3, and a pallet 7. A measurement unit 5 for acquiring information on the loading position of the workpiece W, a storage unit 6 for storing information on the loading position, and a control unit 10 for controlling the operation of each unit are provided. In these components, except for the storage unit 6 and the control unit 10, each unit has a left-right two-pair configuration.

  Here, for convenience of explanation, an xyz orthogonal coordinate system fixed on the ground is set. The x direction is the horizontal direction toward the conveyor 9 when viewed from the hand unit 2, the y direction is the horizontal direction toward the pallet 7 when viewed from the hand unit 2, and the z direction is vertically upward. Then, the left hand unit 2 is a left-handed xyz coordinate system, and the right hand unit 2 is a right-handed xyz coordinate system. Similarly, the left and right XYZ coordinate systems are set for the hand unit 2 as well. Further, the pair of left and right hand portions 2 are in a right-and-left different relationship.

  The hand portion 2 includes a flat hand base portion 20 corresponding to a human palm, plate-like long claws 21 erected from the hand base portion 20, and short claws 22. Two long claws 21 and two short claws 22 are arranged so as to be perpendicular to each other and sandwich opposite corners of a rectangular parallelepiped. That is, the hand part 2 has four claws for gripping the workpiece W, and two long claws and two short claws are attached to adjacent positions.

  Both the above-mentioned two long claws 21 are fixed to the hand base portion 20. The two short claws 22 are both movable claws and can be moved in parallel to the hand base portion 20 by an opening / closing drive portion 2a formed of, for example, an air cylinder or a hydraulic cylinder (FIGS. 2 and 3A). By moving the short claw 22 by the opening / closing drive unit 2a as indicated by the arrows X1 and Z1, the hand unit 2 can be opened and closed by changing the distance between the long claw 21 and the short claw 22, and the workpiece W is gripped. Or release. The movement distance, that is, the stroke of the short claw 22 is a stroke that can cover the minimum to maximum dimension of the workpiece to be gripped, and can handle workpieces W having different dimensions depending on the type. In the present embodiment, among the four claws, the long claws 21 are fixed and the short claws 22 are variable, but all four claws can be movable.

  Moreover, the hand part 2 is provided with the distance sensor 2b for detecting the movement position of the above-mentioned short nail | claw 22 (FIG. 2, FIG.3 (b)). The thickness a of the short nail 22 and the distance b between the distance sensor 2b and the long nail 21 are known, and the distance d between the distance sensor 2b and the short nail 22 is a measured value. The distance L is determined as L = b−a−d. Therefore, when the distance L when the hand unit 2 is gripping the workpiece W is obtained, the cross-sectional dimensions of the workpiece W (La and Lb shown for the workpiece W in FIG. 1) can be measured. That is, a workpiece measuring unit that measures the dimension of the workpiece W is configured using the distance sensor 2b.

  Further, at least one of the long claws 21 is provided with a stress sensor 1 a for measuring an external force acting on the long claws 21. The stress sensor 1a can be configured using a strain gauge or the like. A commercially available 6-axis force sensor or load cell can be used as the stress sensor 1a.

  The arm portion 3 includes a support member 31 provided vertically from near the floor, a horizontal member 32 projecting like a cantilever from the support member 31, and a vertical member 33 suspended from the horizontal member 32. (These are collectively referred to as an arm base portion 30). The horizontal member 32 is moved up and down along the column member 31 by the vertical drive unit 3a (FIG. 2). The vertical member 33 is horizontally moved along the horizontal member 32 by the contact / separation driving unit 3b.

  The rotating portion 23 holds the hand base portion 20 of the hand portion 2 with respect to the vertical member 33 so as to be rotatable around the y axis (Y axis) as indicated by arrows R and R1. Further, the rotating unit 23 can hold the hand unit 2 at a predetermined rotation angle by a rotation driving unit (not shown).

  The transport unit 4 includes a transport base unit 40 that moves on the two rails 41 disposed on the floor surface by the transport drive unit 4a. The conveyance base unit 40 holds the above-described support member 31, and thus the arm unit 3, the rotating unit 23, and the hand unit 2 in its entirety. Therefore, the hand unit 2 moves along the rail 41 when the transport unit 4 moves along the rail 41.

  From the above configuration, the hand unit 2 can move or rotate about four axes. These axes are the axis for rotating the hand part 2 to rotate the work W by the rotating part 23, the axis for moving the work W up and down by the arm part 3, and the left and right sides so as to correspond to the length dimension of the work W. The shaft includes four axes that change the interval between the hand portions 2 and the shaft that moves the workpiece W by the transport portion 4 between the conveyor 9 and the pallet 7.

  The measuring unit 5 is configured so that the position of the long claw 21 of the hand unit 2 can be grasped as a coordinate value in a three-dimensional space by the xyz coordinate system. The acquisition of coordinate values is performed by measuring the amount of parallel movement and the amount of rotational movement of each unit by each drive unit, that is, the vertical drive unit 3a, the contact / separation drive unit 3b, the conveyance drive unit 4a, and the rotation drive unit of the rotation unit 23, This is done by accumulating. For example, when each drive unit is driven by a motor, the number of rotations of the motor can be obtained by a rotary encoder, or the corresponding movement amount can be calculated by counting the control pulses of the pulse motor.

  The pallet 7 includes a pallet body 70 provided with a work overturn prevention member 71 so that the long works W can be stacked in multiple stages. The length of the pallet main body 70 is adjusted to the length of the workpiece W, and the width of the pallet main body 70 is adjusted to a dimension capable of efficiently aligning the plurality of workpieces W without generating an empty space. The work overturn prevention member 71 prevents the work W loaded on the pallet body 70 from overturning, and is composed of a folding pole or the like. The work overturn prevention member 71 can be provided as necessary.

  The control unit 10 can be configured using an electronic computer having a general configuration including a CPU, a memory, an external storage device, a display device, an input device, and the like, a built-in control computer, a sequencer, and the like. The storage unit 6 may use a storage device built in the control unit 10.

  In the palletizing apparatus 1 having the above-described configuration, the control unit 10 receives signals and information from the sensors of each unit and the measurement unit 5 and controls each driving unit, thereby performing a palletizing operation autonomously. The control unit 10 acquires output information from the measurement unit 5, the stress sensor 1a, and the distance sensor 2b in real time for an autonomous palletizing operation. For example, as will be described in detail later, the dimension La of the workpiece W is acquired by the distance sensor 2b, and the workpiece W alignment information and the movement information from the measurement unit 5 by the stress sensor 1a are used to determine the size on the pallet main body 70 shown in FIG. The position of the point p1, which is the work loading position, can be acquired.

  The control unit 10 can also reversely calculate the position of the end point p0 of the pallet from the dimension La. The distance between both end points p0 and p2 of the pallet, that is, the width of the pallet main body 70, can be input to the control unit 10 as a predetermined value and stored in the storage unit 6 in advance. Therefore, the control unit 10 can acquire the unloaded space in the pallet main body 70, that is, the distance between the points p1 and p2 from the position information of the points p0, p1 and p2.

  From the above, when the control unit 10 moves the hand unit 2 holding the workpiece W by the arm unit 3 and the transport unit 4 and loads the workpiece W on the pallet 7, the measuring unit 5 causes the measurement unit 5 to load the workpiece W. When the loading position (point p1) is acquired and stored in the storage unit 6 and the next workpiece W is loaded on the pallet 7, the loading position of the workpiece W is estimated based on the loading position stored in the storage unit 6. Can be determined.

  According to the palletizing apparatus 1 of the present embodiment, the actual loading position of the workpiece W, that is, the position of the point p1 is grasped, and the loading position information is fed back to the loading of the next workpiece W. It is possible to cope with dimensional variations of individual workpieces W and pallets 7 with reference to the loading position of workpieces W, and it is autonomous and flexible by preventing interference between workpieces during palletizing and generation of gaps between palletized workpieces. And palletizing at high speed.

  Next, the movement of the workpiece W and the palletizing operation by the palletizing apparatus 1 will be described in detail with reference to FIGS. The above-mentioned FIGS. 1-3 are also referred suitably.

  FIG. 4 shows the workpiece W0 loaded on the pallet 7, the workpiece W moving to the pallet 7, and the workpiece W in a waiting state stationary on the side of the stopper 91 of the conveyor 9, with attention paid to the workpiece. In the example shown in this figure, the workpieces W0, W, W are translated and palletized while maintaining substantially the same posture.

  The workpiece W supplied to the palletizing apparatus 1 moves on the conveyor 9 and stops horizontally at the position of the stopper 91 on the end face of the conveyor 9. A long workpiece W positioned by the stopper 91, for example, a cardboard box in which a product is packed, is picked by two left and right hand portions 2 (not shown). The workpiece W2 is gripped (chucked) with four claws (not shown).

  FIG. 5 shows the trajectory of the hand unit 2 accompanying the palletizing operation. Due to the symmetry of the device, the trajectory is sufficient when considered in the xz plane. The positions of the points P1 to P5 in the figure indicate points that the specific part of the hand unit 2 should pass, that is, teaching points. In this example, the corner portion of the work W on the two long claws 21 side is the specific portion of the hand portion 2. The teaching point is a space reference position for maintaining the standard operation of the palletizing device 1, and hence the hand unit 2. Each position of the points P1 to P5 may be a predetermined value, may be a set value, or may be a measured value. Normally, the positions of the points P3, P4, and P5 naturally change as the work for sequentially palletizing the workpiece W progresses.

  The hand unit 2 is rotated by a predetermined angle by the rotating unit 23 (FIG. 1) in accordance with the known inclination angle of the conveyor 9 when gripping the workpiece W at the point P <b> 1 positioned by the stopper 91. Further, the posture of the workpiece W is returned to the horizontal while the hand unit 2 grips the workpiece W and lifts it to the point P2 or after the lifting. In the case of a standard workpiece, the control unit 10 moves the hand unit 2 and thus the workpiece W to the point P3 and further to the point P4. The x coordinate values of the points P3 and P4 are the same x4.

  Next, the control unit 10 controls each driving unit and pushes the workpiece W from the point P4 toward the point P5 (coordinate value x5) by the long claw 21 equipped with the stress sensor 1a. A distance Δx = x4−x5 is a push allowance (or clearance). At this time, the reaction force from the previously loaded workpiece W0 to the long claws 21 is measured by the stress sensor 1a. The control unit 10 determines that the gap for moving the workpiece W has disappeared when the measured value exceeds a predetermined value, stops the movement of the hand unit 2, and stores the coordinates of the point P5 in the storage unit 6 at that time. Remember. The position coordinates of each point are acquired by the measurement unit 5.

  The above operations are summarized as follows. That is, in the palletizing device 1, the hand unit 2 has at least two types of claws for gripping the workpiece W, and the long claws 21 are provided with a predetermined clearance Δx from the planned loading position (position of the point P5). After the work W is placed on the pallet 7 and the short claws 22 are pulled out, the work W is pushed to reduce the clearance Δx.

  In addition, the control unit 10 measures the reaction force acting on the claw (long claw 21) pushing the workpiece W when the clearance Δx is reduced by the stress sensor 1a, and the position where the reaction force greater than a predetermined value is measured is measured. Let W be the loading position. The predetermined value used for the reaction force determination can be determined based on the actual measurement value in consideration of the weight and strength of the workpiece W, the strength of the hand portion 2, and the like.

  The operation of the hand unit 2 will be described more specifically. As illustrated in FIG. 6A, the hand unit 2 grips the workpiece W and moves from the conveyor 9 onto the pallet. As shown in FIG. 6B, the movement position is a position away from the workpiece W0 on the pallet 7 by a predetermined clearance Δx. The hand unit 2 that grips the workpiece W is lowered as indicated by the arrow z1.

  Next, as shown in FIG. 6 (c), the hand part 2 spreads its short claws 22 (the opening / closing drive part 2a and the like are not shown), and then the short claws 22 come off the workpiece W and only the long claws 21 are present. Is in a state of being hung on the workpiece W. That is, the hand part 2 is pulled out in the direction of the arrow y1, and the short claw 22 is released. At this time, the workpiece W is supported by the lower long claws 21.

  Next, as shown in FIG. 6D, the hand portion 2 is moved in the direction of the arrow x1, and the workpiece W is pushed toward the workpiece W0 by the long claw 21 provided with the stress sensor 1a. The clearance Δx is filled. The pushing operation by the hand unit 2 is controlled and stopped based on the measurement value from the stress sensor 1a. Thereafter, as shown in FIG. 6E, the hand portion 2 is pulled out in the direction of the arrow y2, and the workpiece W is palletized with no gap beside the workpiece W0.

  Next, how to deal with variations in workpiece dimensions will be described. In the case of a workpiece having a standard size, as shown in FIG. 7A, the workpiece W0 first loaded on the pallet 7 is lowered to the position of the point P4 on the pallet body 70 and is laterally pushed to the position of the point P5. And palletized. The position of the point P0 at the end of the pallet main body 70 (x coordinate value x0, hereinafter the same) is known, and the x coordinate value x4 of the point P4 is sufficiently from the x coordinate value x0 of the point P0 with the point P0 as a reference point. It is set to a position with a margin. That is, if the distance D is D = x4-x0, the distance D may be larger than the upper limit value of the change in the width dimension of the workpiece W0.

  After loading the first workpiece W0, the position of the point P5 becomes the reference point instead of the point P0. The position of the point P5 is known from the coordinate value measured by the measuring unit 5. Therefore, as shown in FIG. 7B, the position of the point P7 where the second workpiece W is lowered is set to a position where a sufficient margin is provided from the point P5. That is, x7 = x5 + D. The same applies hereinafter.

  In the above description, the work W is arranged on the surface of the pallet main body 70. However, the work W can be stacked on the pallet 7 in multiple stages. Therefore, the above procedure is repeated for each stage.

  A workpiece W0 shown in FIG. 8A is a workpiece having a non-standard dimension, and is a workpiece having a dimension in the x direction larger by ΔL0 than the standard workpiece dimension described above. The dimension of the workpiece is obtained by measuring the amount of movement of the short claw 22 by the distance sensor 2b provided in the hand unit 2. Then, the setting of the point P4 with respect to the first workpiece W0 is set by correcting by ΔL0. For example, the distance D described above may be corrected to x4 = x0 + (D + ΔL0).

  Further, as shown in FIG. 8B, when the dimension in the x direction of the next workpiece W is large by ΔL, the setting of the point P7 is set by correcting by ΔL. For example, the distance D described above may be corrected to x7 = x5 + (D + ΔL). The same applies hereinafter. Whether the workpiece is standard or non-standard can be determined by comparing ΔL0 or ΔL with the distance D, and whether or not to correct can be determined based on a predetermined criterion.

  According to the palletizing apparatus 1 of the present embodiment, the actual workpiece loading position on the pallet is grasped by the measuring unit 5 and the loading position information is fed back to the loading of the next workpiece. Can be palletized without being affected. In other words, it is possible to cope with dimensional variations of individual workpieces and pallets based on the loading position of workpieces already loaded, and it is flexible by preventing interference between workpieces during palletizing and gaps between palletized workpieces. And palletizing at high speed.

  Further, according to the palletizing device 1 having the function of moving the hand unit 2 by the arm unit 3, the work can be moved while the short claws are released, so that the work can be closely aligned with each other. In addition, when opening and closing the nail, there is no need to consider securing clearance for opening and closing.

  Moreover, according to the palletizing apparatus 1 provided with the stress sensor 1a in the hand portion 2, it is possible to appropriately push and align the workpieces without being influenced by the variation in clearance. Moreover, it can prevent that a workpiece | work and a hand part are damaged by the excessive force added to the workpiece | work.

(Second Embodiment)
FIGS. 9A and 9B show the state of palletizing by the hand portion of the palletizing apparatus according to the second embodiment. As shown in FIG. 9A, the present embodiment relates to a palletizing apparatus that uses a short work as a work to be palletized as compared to the long work in the first embodiment. That is, it is not necessary to hold the workpiece W at both ends in the length direction, and the palletizing apparatus 1 of this embodiment uses the hand unit 2 only on one side. In this case, the dimensional shape of the pallet 7 is also different from the pallet 7 in the first embodiment, as shown in FIG.

  About another point, it is the same as that of 1st Embodiment. Such a palletizing apparatus 1 for palletizing a short workpiece W can be realized by using either the left or right hand part 2 of the palletizing apparatus 1 in the first embodiment. In addition, the palletizing device 1 dedicated to the short workpiece W including only the hand portion 2 on one side from the beginning can be provided.

(Third embodiment)
10 (a) to 10 (c) and FIGS. 11 (a) to 11 (e) show the state of palletizing by the hand portion of the palletizing apparatus according to the third embodiment. The palletizing apparatus according to the present embodiment includes an up-and-down rotating unit (not shown) in which the long claw 21 of the hand unit 2 is as long as the length of the workpiece W, and the hand unit 2 tilts downward from the horizontal direction to the vertical direction. The point is different from the second embodiment, and the other points are the same.

  As shown in FIGS. 10A, 10B, and 10C, the palletizing apparatus grips the workpiece W on the conveyor 9 with the hand portion 2 and rotates downward, and thereafter, FIGS. 11A to 11E. As shown, the workpieces W can be two-dimensionally arranged on a pallet (not shown).

  As shown in FIGS. 11 (a) and 11 (b), the workpiece W gripped by the hand unit 2 is lowered in the direction of the arrow z1 toward the position of the workpiece W1 indicated by the broken line adjacent to the workpiece P0 that has already been palletized. And placed. Next, as shown in FIG. 11 (c), the short claw 22 of the hand part 2 is opened to release the grip, the hand part 2 is pulled up in the direction of the arrow z2, and the short claw 22 is above the workpiece W. To escape. After that, as shown in FIG. 11 (d), the work unit 2 is moved in the horizontal direction by the two long claws 21 by moving the hand unit 2 in the directions of the arrows x1 and y1.

  By the operation of the hand unit 2 described above, the workpiece W is palletized so as to be in close contact with the workpiece P0 that has already been palletized. Each of the two long claws 21 is provided with a stress sensor 1a, and movement stop control of the hand unit 2 is performed by an output signal thereof. After the workpiece W is palletized, as shown in FIG. 11E, the hand portion 2 is pulled up in the direction of the arrow z3, and the next workpiece is palletized.

  The work loading position information acquisition, clearance setting method, and the like are the same as those in the first and second embodiments. Further, the measurement unit 5 acquires not only the x coordinate value but also the y coordinate value as the workpiece loading position information, and these pieces of information are stored in the storage unit 6 and the workpiece is two-dimensionally aligned by the control unit 10. Used for.

  According to the palletizing apparatus of the present embodiment, the actual workpiece loading position can be grasped, and the loading position information can be fed back to the loading of the next workpiece. Can be palletized by two-dimensional alignment. In addition, since it is possible to cope with dimensional variations of individual workpieces and pallets, it is possible to flexibly palletize by preventing interference between workpieces during palletizing and generation of gaps between palletized workpieces.

(Fourth embodiment)
FIGS. 12A and 12B show a hand portion of a palletizing apparatus according to the fourth embodiment, and FIGS. 13A to 13D show a palletizing operation by the apparatus. Unlike the first embodiment, the palletizing device of this embodiment differs from the first embodiment in that one of the long claws 21 in the hand portion 2 of the palletizing device 1 in the first embodiment is a fixed short claw 22. The point is similar.

  FIG. 13A shows a state where the hand unit 2 holding the workpiece W is descending toward the pallet 7 in the direction of the arrow z1, and FIG. 13B shows the short claw of the hand unit 2 when the workpiece W is lowered. The state where 22 is pulled out in the direction of the arrow y1 is shown. In this state, the workpiece W is placed in a state where the bottom surface thereof is in contact with the pallet body surface of the pallet 7.

  FIG. 13C shows a state in which the workpiece W is laterally pushed and aligned by the long claw 21 provided with the stress sensor 1a, and FIG. 13D shows that the hand portion 2 is pulled out after the workpiece is loaded. Indicates the state.

(Fifth embodiment)
14A to 14D show stepwise loading of a workpiece onto a pallet by the palletizing apparatus according to the fifth embodiment. In the present embodiment, the palletizing device 1 in the first embodiment is used to form a narrow space on the pallet, for example, a space in which a work W composed of a cardboard box is deformed and stacked in a gap (unloaded portion). The operation when loading a work will be described. As shown in FIG. 14A, the narrow space is a space S between the work W0 loaded earlier on the pallet 7 and the work fall prevention member 71 at the rear end portion in the work alignment direction.

  In order to load the workpiece W smoothly in such a space S without deforming it, the control unit 10 tilts and lowers the workpiece W. That is, the control unit 10 tilts the last workpiece W aligned near the rear end side of the workpiece overturn prevention member 71 from the upper side of the planned loading position in a state where the last workpiece W is inclined by the angle θ toward the workpiece W0 loaded earlier. , Descend in the direction of arrow z1. The positional relationship between the angle θ and the workpieces W0 and W will be described later (see FIG. 15).

  As shown in FIG. 14B, the control unit 10 stops the lowering when the lower part of the work W enters between the work W0 and the work fall prevention member 71, and the work W0 loaded earlier. The workpiece W is erected by rotating back by an angle θ around the upper rear end corner of the. Before or after the return rotation, the hand portion is pulled out by a distance that gives a predetermined margin to the length of the short claw 22 in order to release the short claw 22.

  Thereafter, as shown in FIG. 14C, the workpiece W is lowered in the direction of the arrow z2 in an upright state, and the hand portion is pulled out. Then, as shown in FIG. 14D, the workpiece W falls by its own weight, and the palletizing of the workpiece W is completed.

  Next, the relationship between the position of the upper rear end corner portion Q of the workpiece W0 and the center position G of the workpiece W will be described with reference to FIG. This determines from which position P3 the workpiece W should be lowered, and at which position the descent should stop and start rotating. That is, the x-direction distance Dx from the rear end in the alignment direction of the workpiece W0 to the center position G and the z-direction distance Dz from the position of the loading surface to the center position G are obtained.

  Here, the width dimension La, the height dimension Lb of the workpiece W, the height dimension Lc of the workpiece W0, the rotation angle θ of the workpiece W, and contact from the bottom surface of the workpiece W when the workpiece W contacts the upper rear end corner Q. It is assumed that the distance δ between the points is a measured value or a set value and is known. For example, δ and θ are set values (design values), and La, Lb, and Lc are measured values measured by the distance sensor 2b of the hand unit.

Using the above-mentioned known values, Dx and Dz are obtained as follows.
Dx = (La / 2) cos θ− (Lb / 2) sin θ + δsin θ,
Dz = (La / 2) sin θ + (Lb / 2) cos θ + δcos θ + Lc.

  According to the palletizing operation of the present embodiment, when the clearance for loading the workpiece is small (when the workpiece can be loaded but there is not enough room for loading), the workpiece is reliably loaded by avoiding interference with the corner of the workpiece. it can.

(Sixth embodiment)
FIG. 16 shows a palletizing operation by the palletizing apparatus according to the sixth embodiment. The palletizing apparatus according to the present embodiment is provided with a guide plate 8 on the pallet 7 side used for smooth loading when a work is loaded using the palletizing apparatus 1 according to the first embodiment. That is, the guide plate 8 is effectively used when a workpiece is loaded in a space having a small clearance for loading the workpiece between the workpiece W0 loaded earlier and the workpiece fall prevention member 71 at the rear end portion in the workpiece alignment direction. It is done.

  According to the palletizing apparatus of the present embodiment, when the clearance for loading the workpiece is small, the workpiece W and the corner portion (edge) of the workpiece overturn preventing member 71 can be avoided and reliably loaded. The guide plate 8 of this embodiment can be used together more effectively during the palletizing operation in the fifth embodiment described above.

(Seventh embodiment)
FIGS. 17A and 17B show the palletizing operation by the palletizing apparatus according to the seventh embodiment. The palletizing apparatus according to the present embodiment is for loading workpieces using the palletizing apparatus 1 according to the first embodiment, and relates to a case where workpieces that can be loaded in multiple stages are loaded in multiple stages on a pallet.

  That is, as shown in FIG. 17A, the control unit 10 determines that the dimension La of the workpiece W measured by the workpiece measuring unit configured using the distance sensor 2b or the like is the pallet at the stage where loading is scheduled. 7 is larger than the dimension α of the unstacked portion of the first stage (α ≦ La), as shown in FIG. 17B, the workpiece W is loaded on the upper stage, that is, the second stage. The hand unit 2 is controlled. The determination of the size comparison of the dimensions La and α can be changed depending on the type of the workpiece W. For example, in the case of a work in a corrugated cardboard box that allows a slight deformation, a certain permissible value β can be introduced and judged by an expression such as α + β ≦ La. Here, for example, when β = 5 mm, the dimension β is absorbed by deformation or movement of each workpiece.

  The palletizing operation as described above can also be applied to multi-stage loading. That is, in the example shown in FIG. 18, the work W scheduled to be loaded at the end of the second stage is loaded on the third stage without being loaded on the second stage. In addition, in the last unloaded space in the first stage in FIGS. 17A and 17B and the last unloaded space in the second stage in FIG. 18, when a work W having a size that can be loaded in this space is obtained, That is, a workpiece having a size smaller than the size of the unloaded portion is selected and loaded. Until then, the workpieces W are sequentially aligned and stacked on the upper stage.

  According to the palletizing operation of the present embodiment, it is possible to determine whether loading is possible in advance and to select and load a workpiece having a loadable size. The palletizing operation can be continued without generating an unloading space on the pallet and without stopping the palletizing operation, and a work can be efficiently loaded without a loading error.

(Eighth embodiment)
19 (a) and 19 (b) show palletizing operations by the palletizing apparatus according to the eighth embodiment. The palletizing apparatus according to this embodiment is the same as the palletizing apparatus 1 according to the first embodiment, and efficiently loads a workpiece having flexibility in shape and posture. That is, when the workpiece W has a plurality of bottom surfaces that can be loaded on the pallet and the shape of the bottom surface varies depending on the loading posture, the control unit 10 determines the bottom surface of the workpiece during loading according to the dimensions of the unloaded portion of the pallet. Load the workpiece by selecting.

  In FIG. 19A, the dimensions of the workpiece W to be loaded are the horizontal dimension La and the vertical dimension Lb, and it is assumed that there is a relationship of Lb <α <La with respect to the dimension α of the unloaded portion in the pallet 7. . The dimensions La and Lb are measured by the distance sensor 2b of the hand unit 2. The dimension α is obtained from the known pallet dimension and the workpiece loading position measured by the measuring unit 5. The work W cannot be palletized in an upright posture, but can be palletized when it is placed sideways. Therefore, as shown in FIG. 19B, the control unit 10 palletizes the workpiece W in a state of being rotated horizontally.

  According to the palletizing operation of the present embodiment, it is possible to flexibly cope with dimensional variations of individual workpieces and pallets, and to load the workpieces on the pallet appropriately, that is, without generating a gap.

(Ninth embodiment)
FIGS. 20A to 20D show examples of the posture of the work when the work is gripped by the hand unit of the palletizing apparatus according to the ninth embodiment and placed on the pallet. The present embodiment relates to a method of using the hand unit 2 of the palletizing apparatus 1 in the first embodiment. That is, when there are a plurality of selectable stacking orientations of the workpiece W, when the control unit 10 laterally presses the workpiece W on the pallet, the position of the long claw 21 of the hand unit 2 becomes the pressing side position. As described above, the work W is gripped after the hand unit 2 is rotated in advance. In this case, the workpiece can always be laterally pushed and moved by the specific long pawl 21. Therefore, the stress sensor 1a may be provided for the minimum necessary, that is, one long pawl 21 and the cost can be reduced.

  Therefore, the hand unit 2 holds the workpiece W as shown in FIG. 20A when the workpiece W is not rotated, and holds the workpiece W as shown in FIG. 20B when the workpiece is rotated 90 °. When the work is rotated 180 °, it is gripped and rotated as shown in FIG. 20 (c), and when the work is rotated 270 °, as shown in FIG. 20 (d). Grasp and rotate.

  According to the usage method of the hand part 2 described above, the loading of the workpieces W1 to W10 onto the pallet 7 as shown in FIG. 21 is realized. In this loading example, in order to increase the loading efficiency, the vertical and horizontal positions are mixed, and the stacking is reversed by 180 ° in consideration of the weight balance of the workpiece.

  In the above workpiece loading example, the workpieces W1 to W4, W6, W8, and W9 are laterally pushed by the long claws 21 and loaded. The workpieces W5, W7, and W10 are loaded by the loading method in the fifth embodiment or its application. For example, the workpiece W7 is tilted and stacked as shown in FIG. 22A, and the workpiece W10 is tilted and stacked as shown in FIG. 22B.

  The stacking example shown in FIG. 21 shows an example in which the vertical and horizontal dimensions of the workpiece are greatly different. If the difference between the vertical and horizontal dimensions is slight, it is possible to realize stacking using the stacking method according to the eighth embodiment. For example, when placing and stacking workpieces in sequence in a certain loading stage, by laying down the remaining several workpieces from the relationship between the workpiece dimensions acquired in real time and the unloaded space on the pallet It can be predicted that it can be packed densely.

  Therefore, the control unit 10 loads a plurality of workpieces sideways instead of laying down only the last workpiece as in the eighth embodiment. When the work in the middle is laid down and stacked, as described above, the hand unit 2 may be rotated in advance so that the work can be pushed sideways with the long claws 21, and then the work may be gripped.

  As in the present embodiment, the palletizing device 1 can measure the measurement unit 5 by selecting the direction of the workpiece freely to achieve dense loading or loading in consideration of the center of gravity of the entire workpiece on the pallet. This is because the workpiece measuring unit by the distance sensor 2b is provided, and the workpiece loading position on the pallet, the dimension of the unloaded portion, and the workpiece dimension can be measured and grasped. By grasping such dimensions, it is possible to feed back such information to subsequent loading, and it is possible to set not only the next workpiece but also the loading position and loading method of the workpiece one after another.

(Tenth embodiment)
23 to 26 show a tenth embodiment. This embodiment is different from the other embodiments described above in that the workpiece is moved along the workpiece alignment direction to the planned loading position and then placed at a position returned by a predetermined distance. That is, as shown in the flowchart of FIG. 23, the control unit 10 conveys the workpiece to a predetermined position on the pallet (S1), presses the workpiece against the already loaded workpiece or the tipping prevention member 71 (S2), and then The workpiece and the hand unit are moved backward by a predetermined distance (S3), the workpiece is placed on the pallet (S4), and the processing is continued or terminated (S5). Specifically, as shown in FIG. 24A, when the workpieces W1 to W7 are already loaded on the pallet 7, and the workpiece W8 is placed on the upper surface of the workpiece W3 and before the workpieces W6 and W7. Will be explained. As shown in FIG. 24 (b), the control unit 10 spreads and pulls out the short claw 22, and then presses the workpiece W8 against the workpieces W6 and W7 to move to the planned loading position. Then, as shown in this figure, when the upper surface of the workpiece W2 is higher than the upper surface of the workpiece W3, the corner portion Q of the workpiece W2 is projected. Next, as shown in FIG. 24 (c), the control unit 10 moves the workpiece W8 backward by a predetermined distance δ, and as shown in FIG. 24 (d), pulls out the long pawl 21 and moves the workpiece W8 to the workpiece W3. Place on top. At this time, the workpiece W8 is placed in an upright state on the workpiece W3 while avoiding the protruding corner Q of the workpiece W2.

  However, as shown in FIGS. 24 (a1) and 24 (b1), when the work W8 is placed at the expected loading position without being retracted, the work W8 is positioned at the protruding angle of the work W2 as shown in FIG. 24 (d1). It rides on the part Q and is placed in a tilted state. If such climbing onto the corner Q occurs, in the worst case, the tilted workpiece may fall or fall, and the subsequent work may not be continued normally. The present embodiment can avoid such a problem.

  As shown in FIGS. 25 (a) and 25 (b), the gap of the predetermined distance δ is closed by the pushing operation by the workpiece W9 to be placed next. At this time, the obstacle due to the protruding corner portion Q of the workpiece W2 is eliminated by deformation of the workpieces W2 and W8. The subsequent workpiece W9 is placed at a distance δ from the workpiece W8, as shown in FIG. Since there is no adjacent work in the last work in each alignment direction, a gap remains. Therefore, if there is a problem, the work part 2 may be pushed after the work is placed (dropped).

  Another example of exception handling and workpiece loading for the palletizing process described above will be described. As shown in FIGS. 26A to 26D, all the workpieces already loaded on the pallet 7 are packed together without any gaps. This is because when the workpiece is placed directly on the pallet main body 70 or when the workpiece is placed in contact with the workpiece overturn prevention member 71, there is no protruding corner portion Q of the workpiece W2, and therefore, only the predetermined distance δ. This is due to exception handling that omits the backward processing. When the workpiece W is loaded as the second piece following the second-stage workpiece W0, the hand unit 2 is sequentially moved as indicated by arrows z1, y1, x1, and x2, and finally, as shown in FIG. As described above, the workpiece W is moved in the direction of the arrow y2 and loaded at a position away from the workpiece W0 by the distance δ. Before moving the hand part 2 in the direction of the arrow y1, the short claw 22 is spread. Further, of the two long claws 21 of the hand unit 2, the long claw on the side that pushes the work is provided with a stress sensor 1a that measures a reaction force when the work is pushed. As shown in FIGS. 26B and 26C, when the stress sensor 1a moves the work W in the direction of the arrow x1 to close the gap with the work W0, the gap Δx is filled (Δx = 0). It is used to judge. The reaction force acting on the long claw 21 that pushes the workpiece W is measured by the stress sensor 1a, the position where the reaction force greater than a predetermined value is measured is Δx = 0, and the position returned by a predetermined distance δ from that position. The loading position of the workpiece W is set.

  According to this embodiment, in the case of upper stacking, the work can be placed avoiding the protrusion of the corner of the lower work, etc., so that it is possible to prevent problems such as the work being placed obliquely and falling. Since the gap generated by returning the predetermined distance can be sequentially filled by the filling operation by the next workpiece, even if the workpiece W or the pallet 7 has a dimensional variation, the gap between the palletized workpieces is prevented. It can be packed densely. There is no gap between the last workpiece in the workpiece alignment direction, so there will be a gap. However, if there is a problem, after placing (dropping) the workpiece, it may be pushed further by the hand unit 2. it can.

(Regarding the stress sensor in the first, third, fourth and tenth embodiments)
With reference to FIG. 27, the threshold value (predetermined value) compared with the reaction force measured by the stress sensor 1a will be described. When the workpiece W is pressed against another object by the long claws 21, the amount of pressing after the contact with the other object (the amount of movement after the reaction force F starts to rise from zero) and the reaction measured by the stress sensor 1a. The relationship with force shows different characteristics depending on what other objects are pressed against and how they are distributed. For example, when the opponent is a pole-shaped fall prevention member, the workpiece is likely to bend at the left and right ends of the workpiece without the fall prevention member, and the reaction force is considered to be small. According to the actual measurement result, when the workpiece W is pressed against another workpiece, a characteristic like a straight line a is shown, and when the workpiece W is pressed against the tipping prevention member 71, a characteristic like a straight line b is shown. Further, if the work W has different strengths, naturally, data having different characteristics can be obtained. Therefore, it can be understood from the measured value of the reaction force what the workpiece W is pressed against and what strength the workpiece W is.

  Accordingly, the determination of the completion of pushing, that is, the judgment of whether the work W is pushed and moved to close the gap or clearance can be made by comparing the measured value of the reaction force with a predetermined value (threshold value). . More generally, the control unit 10 measures, by a stress sensor, a reaction force that acts on a claw on the side pressing the workpiece provided in the hand unit 2 when the workpiece is moved along the workpiece alignment direction on the pallet. The position where the reaction force equal to or greater than the predetermined value is measured is set as the movement completion position (push-in completion position), and the predetermined value for the reaction force for determining the completion position is set according to the strength of the workpiece. In order to make this determination effectively, a threshold value is set or switched according to the difference in the strength of the workpiece W due to the difference in the product type or the difference in the other party against which the workpiece W is pressed. The strength of the workpiece W may be close to a rigid body or flexible depending on the type of the workpiece W, but is considered to be constant for each type. Therefore, threshold values Fa and Fb may be set for a predetermined push-in amount d for each type, and the threshold value Fa and the threshold value Fb may be appropriately switched during palletizing. The pushing amount d for setting the threshold value Fa and the threshold value Fb may be different. Since the control unit 10 always knows whether the opponent who presses the workpiece W is a workpiece or a fall prevention member, the threshold values Fa and Fb can be switched reliably. By switching between the threshold values Fa and Fb and determining the completion of pushing, the workpiece W palletized by the palletizing device 1 can be properly grasped without being deformed or damaged, and the pushing completion point can be grasped. The work W can be densely loaded on the pallet by preventing the generation of the gap.

(Eleventh embodiment)
28, 29 (a) and 29 (b) show an eleventh embodiment. As shown in FIG. 28, the present embodiment further includes a workpiece measuring unit 50 that measures a workpiece dimension, and the control unit 10 stores the workpiece dimension measured by the workpiece measuring unit 50 and the storage unit 6 in advance. By comparing with the standard workpiece dimensions, the difference in workpiece type is determined. About another point, it is the same as that of the 1st thru | or 10th embodiment mentioned above. The workpiece measurement unit 50 is substantially the same as the workpiece measurement unit in the first embodiment described above, and acquires the vertical and horizontal dimensions of the workpiece W based on the information from the distance sensor 2b of the short claw 22, that is, the measurement. To do. In the first embodiment, the workpiece dimension is used for measuring whether or not the dimension of the workpiece W varies. In this embodiment, it is determined whether the workpiece types are the same or different. This is effective when, for example, the difference between the varieties is unknown, and conversely, it is considered that the size of the workpiece W currently being gripped is unknown. Therefore, when gripping the workpiece W, the gripping is started from the position of the maximum stroke, which is the position where the short claws 22 are most widened, and the distance from the distance sensor 2b when the hand unit 2 is gripping the workpiece W. The cross-sectional dimension of the workpiece W is measured based on the information.

  The palletizing process is performed as shown in FIG. The control unit 10 controls the hand unit 2 to grip the workpiece W (S11), acquires the dimension of the workpiece W (S12), compares the dimensions (S13), and the dimensions are the same within a predetermined allowable range. If there is, it is determined that the type is the same as the previous work (Yes in S14), and is loaded on the pallet (S16). When it is determined that the dimensions are different and the type is not the same as the previous workpiece (No in S14), the control unit 10 outputs a pallet replacement instruction to the outside and loads the workpiece on the replaced pallet. (S16). Thereafter, if the work is not finished (No in S17), the process from Step (S11) is repeated, and if the work is finished (Yes in S17), the process is finished.

  The processing including dimension measurement and comparison in the above-described flowchart is performed for all the workpieces. Usually, the type switching of workpieces is notified or input to the palletizing device 1 in advance, and therefore it is not necessarily performed every time. It is necessary to judge whether the product is different or not at the point when notification or input of product change is made, for example, the distance between processes is long, and after the notification or input of product change is made, the final work before product change is made. Such as when a time lag occurs. Therefore, as shown in FIG. 29 (b), it is first determined whether or not there is a product type change (# 1), and if there is a product type change (Yes in # 1), the same processing as above including pallet replacement is performed ( If there is no change in product type (No in # 1), the workpiece W may be held (# 2) and loaded on the pallet as it is (S16). In this case, it is possible to shorten the time for dimension measurement and determination processing performed by extending the short claw 22 to the maximum stroke, and the palletizing efficiency can be increased. According to the present embodiment, since the difference between the types of workpieces W is determined, it is possible to prevent different types of workpieces W from being mixed on one pallet 7.

  The present invention is not limited to the configuration of each embodiment described above, and various modifications can be made. For example, the configurations of the embodiments can be combined with each other. Moreover, as an opening / closing mechanism of the short claw 22, the example in which the short claw 22 is translated using a cylinder has been shown. However, the present invention is not limited to this, and the short claw 22 can be opened and closed using a hinge. You can combine opening and closing. The number of claws may be two, that is, at least one fixed long claw 21 and one movable short claw 22 that face each other. As another example of the configuration of the hand unit 2, the upper and lower claws can be provided with two upper and lower claws and one side claw for pushing operation, and the upper claw can be a movable claw. In this case, the lengths of the three claws can be the same length, and since there are no claws on the pushed side, there is no need to perform an intermediate operation such as pulling out the short claws before the pushing operation.

  In addition, the determination of the completion position of the operation of moving, pushing, and stuffing the workpiece along the alignment direction does not necessarily have to be based on the measurement value of the reaction force by the stress sensor, but at the loading position stored in the storage unit. You may just make a judgment based on it. In addition, the work shape is not limited to the box shape, and it is sufficient that the work can be aligned and loaded with at least a bottom surface and a left and right surface. , And can be the target of palletizing.

  Moreover, although the length of the pallet showed the same example as the length of the workpiece W in the longitudinal direction in 1st Embodiment, for example, it does not necessarily need to be the same. Moreover, although the workpiece | work measuring part showed the example comprised by the distance sensor 2b, it is not restricted to this, A workpiece | work dimension is acquired by image processing, or a plurality of light-shielding type sensors are arranged, and a workpiece | work dimension in steps from light transmission condition. Or may be measured.

  Further, the measuring unit 5 measures the moving position of each moving unit with a laser distance meter without counting the rotary encoder and control pulses, or acquires position information by laser radar or image processing to obtain the position of the hand unit 2. The position of the long nail 21 may be measured.

DESCRIPTION OF SYMBOLS 1 Palletizing apparatus 10 Control part 1a Stress sensor 2 Hand part 21 Long claw 22 Short claw 2b Work measurement part (distance sensor)
3 Arm part 5 Measuring part 50 Work measuring part 6 Storage part 7 Pallet 71 Work fall prevention member 8 Guide plate W, W0 to W10 Work Q Corner part

Claims (11)

A palletizing device that sequentially conveys workpieces from its supply location and arranges and loads them on a pallet,
A hand portion for gripping a workpiece;
An arm part for moving the hand part;
A measuring unit for obtaining information on the loading position of the workpiece on the pallet;
A storage unit for storing the loading position;
A control unit for controlling the operation of each unit,
The control unit acquires the loading position of the workpiece by the measuring unit when the workpiece is loaded on the pallet by moving the hand unit that grips the workpiece by the arm unit, and stores the loading position in the storage unit. A palletizing apparatus, wherein when a workpiece is loaded on a pallet, a planned loading position of the workpiece is determined based on a loading position stored in the storage unit. It further includes a workpiece measuring unit for measuring workpiece dimensions,
When loading workpieces that can be stacked in multiple stages on a pallet,
The control unit is configured to load the workpiece on the upper stage when the workpiece dimension measured by the workpiece measuring unit is larger than the dimension of the unloaded portion of the pallet in the stage where loading is scheduled. The palletizing device according to claim 1, wherein the palletizing device is controlled.   3. The palletizing according to claim 2, wherein when a workpiece size is larger than a size of an unloaded portion, a workpiece having a size smaller than the size of the unloaded portion is selected and loaded on the unloaded portion. apparatus. The hand portion has at least two types of claws for gripping a workpiece,
2. The long claw is used for pressing the work and closing the clearance after placing a work on a pallet with the predetermined clearance from the expected loading position and pulling out the short claw. Or the palletizing apparatus according to claim 2.   When the clearance is reduced, the control unit measures a reaction force acting on a claw pushing the workpiece by a stress sensor, and sets a position where the reaction force of a predetermined value or more is measured as a workpiece loading position. The palletizing apparatus according to claim 4. The work is a rectangular parallelepiped whose bottom shape when loading onto the pallet differs depending on the loading posture.
6. The palletizing apparatus according to claim 4, wherein the control unit selects a bottom surface of the workpiece at the time of loading according to a dimension of an unloaded portion of the pallet. The pallet has workpiece fall prevention members at both ends of the workpiece alignment direction,
The control unit lowers the last workpiece aligned near the rear end side of the workpiece overturn prevention member from above the planned loading position in a state where the last workpiece is inclined toward the workpiece loaded earlier, 7. The hand unit is controlled so that the work is erected and loaded on a pallet by rotating around an upper rear end corner of the work being carried. The palletizing apparatus according to one item. The pallet has workpiece fall prevention members at both ends of the workpiece alignment direction,
7. The guide plate according to claim 1, further comprising a guide plate on the pallet side for smoothly loading the last workpiece aligned near the rear end side of the workpiece overturn prevention member. The palletizing device described.   2. The control unit according to claim 1, wherein the control unit controls the hand unit to place the workpiece at a position returned by a predetermined distance after the workpiece is moved along the workpiece alignment direction to the planned loading position. The palletizing device described in 1. The control unit measures, by a stress sensor, a reaction force acting on a nail on the side of pressing the workpiece provided in the hand unit when the workpiece is moved along the workpiece alignment direction on the pallet, and the reaction force exceeding a predetermined value is measured. The position where the force is measured is the completion position of the movement,
The palletizing apparatus according to any one of claims 1 to 9, wherein a predetermined value for the reaction force for determining the completion position is set according to a strength of a workpiece. It further includes a workpiece measuring unit for measuring workpiece dimensions,
2. The control unit according to claim 1, wherein the control unit determines whether the workpiece types are different by comparing a workpiece size measured by the workpiece measuring unit with a standard workpiece size stored in advance. The palletizing apparatus according to claim 10.

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