ARTICLE HOLDING DEVICE

An article holding device includes a base portion whose lower surface has a holding portion, flow paths communicated with holes in the holding portion, and needles provided on the base portion in a posture inclined with respect to the holding portion. The holding portion sucks and holds a sheet-like article using a negative pressure generated, by supplying a fluid to the flow paths and ejecting the fluid from the holes, between the holding portion and the article on the holding portion. When the article is easily allows air to pass through, the needles is moved to a protruding position in which the needles protrude downward from the holding portion, and the holding portion holds the article by piercing the article using the protruded needles.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to Japanese Patent Application No. 2017-015317, filed on Jan. 31, 2017, the content of which is hereby incorporated by reference.

BACKGROUND

The present disclosure relates to an article holding device.

There is a known device that holds a thin planar component, such as a semiconductor wafer, using non-contact suction. The device is provided with a base body. The lower surface of the base body has a recessed portion provided with a fluid ejection portion that ejects a fluid (air). The periphery of the recessed portion is a non-contact suction portion. The device holds the article through non-contact suction, using a negative pressure that is generated between the device and the article as a result of the fluid ejected by the fluid ejection portion passing through the non-contact suction portion.

SUMMARY

The known device holds the article through non-contact suction using the negative pressure generated between the device and the article. Therefore, when the article is a sheet-like article having good air permeability and easily allows air to pass through, there is a possibility that the negative pressure will not be generated between the device and the article and the device will not be able to suck the article. In this case, the device cannot hold the article.

It is an object of the present disclosure to provide an article holding device capable of holding an article even when the article is a sheet-like article that easily allows air to pass through.

Embodiments provide an article holding device includes a base portion, flow paths, needles, drivers, an acquisition portion, and a control portion. The base portion includes a holding portion provided on a lower surface of the base portion. The flow paths are communicated with holes provided in the holding portion. The holding portion configured to suck and hold a sheet-like article using a negative pressure. The negative pressure is generated between the holding portion and the sheet-like article on a lower surface of the holding portion by a fluid. The fluid is supplied to the flow paths and is ejected from the holes. The needles are provided on the base portion in a posture inclined with respect to the holding portion. The drivers are configured to move the needles between a protruding position and a retracted position. The protruding position is a position in which the needles protrude downward from the holding portion. The retracted position is a position in which the needles are retracted above the holding portion. The acquisition portion is configured to acquire a command as to whether to move the needles to the protruding position. The control portion is configured to drive the drivers and to move the needles from the retracted position to the protruding position when the acquisition portion acquires a command to move the needles to the protruding position. The control portion is also configured to maintain the needles in the retracted position and to supply the fluid to the flow paths when the acquisition portion acquires a command to prohibit a movement of the needles to the protruding position.

DETAILED DESCRIPTION

First and second embodiments of the present disclosure will be explained sequentially with reference to the drawings. A schematic configuration of a conveyance system1that is common between the first and second embodiments will be explained. In the following explanation, left and right directions, front and rear directions, and up and down directions as indicated by arrows in the drawings are used.

As shown inFIG. 1andFIG. 2, the conveyance system1is provided with a frame2, an articulated robot arm device (hereinafter referred to as an “arm device”)3, article supply devices4and5, a work table6and a PC100(refer toFIG. 9). The frame2is formed by assembling rod members made of iron or aluminum into a rectangular shape. The arm device3, the article supply devices4and5, and the work table6are disposed on the inside of an outer frame of the frame2. The arm device3is an industrial robot, and is able to convey a sheet-like article9held by an article holding device23of the article supply devices4and5to a predetermined conveyance position. The conveyance position of the present embodiment is a position in which the article holding device23is above the work table6and in which the position of the article holding device23in the up-down direction is lower than the position shown inFIG. 2. The conveyance position may be changed as appropriate depending on the structure of the conveyance system, such as an upper portion of a bed portion of a sewing device. The article9of the present embodiment is a cloth piece having a trapezoid shape with round corners. Together with the article supply devices4and5, the arm device3conveys the article9onto the work table6. The arm device3is provided with arm portions11and12, a support portion13and a base portion14. The arm portion11is provided with a rotation linear drive device (hereinafter referred to as a “drive device”)15.

The drive device15is provided with a ball screw16, a first motor18and a second motor19. The ball screw16extends in the up-down direction. The ball screw16is inserted through one end portion of the arm portion11. The drive device15can rotate the ball screw16around its axis by the first motor18. The drive device15can move the ball screw16along its extending direction by the second motor19. The rotation around the ball screw16is rotation around an axis line of the ball screw16in a clockwise direction or a counterclockwise direction. The arm portion12extends in the front-rear direction, and the front end portion of the arm portion12rotatably supports another end portion of the arm portion11. The support portion13extends in the up-down direction, and the upper end of the support portion13rotatably supports the rear end portion of the arm portion12. The base portion14has a plate shape that extends horizontally, and is fixed to the frame2. The base portion14is coupled to the lower end of the support portion13. The arm device3is fixed to the base portion14. The arm device3can rotate each of the arm portions11and12.

The article supply devices4and5have the same structure. Therefore, the article supply device4will be explained in detail and an explanation of the article supply device5will be omitted. As shown inFIG. 3, the article supply device4is provided with an article supply mechanism24and the article holding device23. The article holding device23is common between the article supply devices4and5. The article supply mechanism24supplies the sheet-like article9to the article holding device23. The article supply mechanism24is fixed to the inside of the frame2(refer toFIG. 1). The article supply mechanism24is provided with a placement table21, an air cylinder22and a shaft25. The placement table21has a surface31on which a plurality of the sheet-like articles9can be placed. The surface31extends substantially horizontally, and has a rectangular shape in a plan view. The area of the surface31is larger than the area of the article9. The air cylinder22has a shaft26that extends in the up-down direction, and can move the placement table21in the upward direction. The air cylinder22is a so-called rod-less cylinder. The air cylinder22is provided with a piston (not shown in the drawings) and a main body portion27. The piston is provided inside the shaft26, and has a magnet (not shown in the drawings). The main body portion27is provided on the outer periphery of the shaft26and has a magnet (not shown in the drawings). The magnet of the piston is coupled, by magnetic attraction, with the magnet of the main body portion27via the shaft26. The air cylinder22supplies air to the interior of the shaft26and moves the piston, thus moving the main body portion27along the shaft26. The shaft25extends parallel to the shaft26. The shaft25is inserted through a hole provided in the rear end portion of the placement table21. A rear portion of the placement table21is coupled to the main body portion27. The placement table21moves along the shaft25together with the main body portion27. The air cylinder22is connected to an air compressor (not shown in the drawings) via an air tube (not shown in the drawings). A control portion (not shown in the drawings) of the article supply mechanism24controls an electromagnetic valve (not shown in the drawings) provided in the air tube, and controls the drive of the air cylinder22.

The article holding device23is connected to the arm device3. The article holding device23is fixed to the lower end of the ball screw16. The article holding device23can hold the article9placed on the placement table21in a holding position that faces the placement table21. The holding position is a position shown inFIG. 3. When the article holding device23is in the holding position, a base portion32is located above the placement table21. When the article holding device23is in the holding position, the base portion32is located above the article supply mechanism24.

As shown inFIG. 3toFIG. 11, the article holding device23is provided with the base portion32, flow paths70to78, needles52and54, air cylinders35and36, and a control portion80. The base portion32is a rectangular shaped member in a plan view. As shown inFIG. 6, a virtual line that extends in the front-rear direction at the center of the base portion32in the left-right direction is called a center line M. The base portion32is provided with a holding portion33, a mounting portion34, support portions38,39,48and49, and a supply port37(refer toFIG. 11). The holding portion33is the lower surface of the base portion32and holds the article9. An outer peripheral portion of the holding portion33is a horizontal portion331that extends horizontally. The flow paths70to78are provided in the base portion32, and are communicated with holes61to68provided in the holding portion33.

The holding portion33is provided with a first flow path portion41, a recessed portion43, a second flow path portion42, a first inclined portion44and a second inclined portion45. The horizontal portion331surrounds the first flow path portion41, the recessed portion43, the second flow path portion42, the first inclined portion44and the second inclined portion45. The first flow path portion41, the recessed portion43and the second flow path portion42have a rectangular shape that is long in the front-rear direction in a bottom view. The first flow path portion41, the recessed portion43and the second flow path portion42have the same length in the left-right direction, and are aligned on the center line M of the base portion32from the front to the rear in that order. The first flow path portion41and the second flow path portion42have the same length in the front-rear direction, and their length is longer than the length of the recessed portion43in the front-rear direction. The first flow path portion41is provided with the holes61,63,65and66, and protrudes below the recessed portion43. The holes61,63,65and66are provided on one side of the holding portion33in a predetermined direction. The predetermined direction of the present embodiment is the front-rear direction, and the one side is the front side. The predetermined direction is parallel to the horizontal portion331of the holding portion33. The holes61and65are provided in the right surface of the first flow path portion41and open rightward direction, and the holes63and66are provided in the left surface of the first flow path portion41and open leftward direction. The holes65and66are disposed forward of the holes61and63such that the holes65and66face each other. The recessed portion43is provided between the hole61and the hole62, and is recessed above the horizontal portion331of the holding portion33. The recessed portion43is recessed above the holes61to68. The second flow path portion42is disposed on the opposite side to the first flow path portion41with respect to the recessed portion43, is provided with the holes62,64,67and68, and protrudes below the recessed portion43. The holes62,64,67and68are provided on the other side of the holding portion33in the predetermined direction. The other side is opposite from the one side. In the present embodiment, the other side is the rear side. The holes64and67are provided in the right surface of the second flow path portion42and open rightward direction, and the holes62and68are provided in the left surface of the second flow path portion42and open leftward direction. The holes61to68are provided below the upper end of the recessed portion43. The holes67and68are disposed rearward of the holes62and64such that the holes67and68face each other. The direction in which the holes61,63,65and66are open is parallel to the direction in which the holes62,64,67and68are open. The holes61to68have the same size and are in the same position in the up-down direction. The holes61,64,65and67are located to the right of (in a first direction from) the center line M of the base portion32. The holes62,63,66and68are located to the left of (in a second direction from) the center line M. In the front-rear direction, a distance from the holes61and63to a rear end portion of the first flow path portion41and a distance from the holes62and64to a front end portion of the second flow path portion42are shorter than half the length of the recessed portion43.

The first inclined portion44is provided to the right of the first flow path portion41, the recessed portion43and the second flow path portion42. The first inclined portion44is connected to the upper end of the first flow path portion41, the recessed portion43and the upper end of the second flow path portion42, and is inclined downward to the right. The second inclined portion45is provided to the left of the first flow path portion41, the recessed portion43and the second flow path portion42. The second inclined portion45is connected to the upper end of the first flow path portion41, the recessed portion43and the upper end of the second flow path portion42, and is inclined downward to the left. The first inclined portion44and the second inclined portion45are disposed facing each other in the left-right direction such that the first flow path portion41, the recessed portion43and the second flow path portion42are positioned therebetween. The article holding device23ejects, from the holes61to68, a fluid supplied to the flow paths70to78. Thus, the article holding device23sucks and holds the article9, using the negative pressure generated between the holding portion33and the article9. The fluid of the present embodiment is air.

The flow path70extends in the front-rear direction. The flow path70branches into the eight flow paths71to78that extend in the left-right direction. The flow path71is communicated with the hole61, and extends to the right (in the first direction) toward the hole61. The flow path72is communicated with the hole62, and extends to the left (in the second direction), which is the opposite direction from the first direction, toward the hole62. The flow path73is communicated with the hole63and the flow path71. The direction from the flow path73toward the hole63is the leftward direction. The flow path74is communicated with the hole64and the flow path72. The direction from the flow path74toward the hole64is the rightward direction. The flow paths75and77extend to the right, and are communicated with the holes65and67, respectively. The flow paths76and78extend to the left, and are communicated with the holes66and68, respectively.

As shown inFIG. 4,FIG. 7andFIG. 9, the mounting portion34is detachably mounted on the lower end of the ball screw16of the arm device3. The mounting portion34is provided at the center of the upper surface of the base portion32. The mounting portion34has a circular cylindrical shape in a plan view, and is inserted through the lower end of the ball screw16.

As shown inFIG. 5toFIG. 9, the needles52and54are provided in the base portion32in an inclined posture with respect to the holding portion33. In the left-right direction that is parallel to the horizontal portion331, the needles52and54are disposed facing each other such that the holes61to68are positioned therebetween. The needles52and54are inclined with respect to the holding portion33in a direction in which the leading end of each of the needles52and54are separated from the holes61to68. The needles52are located to the right of the center line M. The needles52include six needles521to526and their leading ends are directed to the lower right side. The needles521to526are aligned at substantially equal intervals in the front-rear direction. The needles54are located to the left of the center line M. The needles54include six needles541to546and their leading ends are directed to the lower left side. The needles541to546are aligned at substantially equal intervals in the front-rear direction. The needles52and54are respectively inserted through the holes51and53provided in the holding portion33. The holes51and53have a rectangular shape and extend in the front-rear direction.

The support portions38and48are provided to the right of the center line M, and the support portions39and49are provided to the left of the center line M. The support portion38extends in the front-rear direction and movably supports the needles52. The support portion38has members381and382. The member381has an L shape in a front view, and has a section383that is inclined upward to the right and a section384that is inclined downward to the right from the left end of the section383. The member382has a plate shape that extends in parallel to the section384, and is coupled to the section384. The support portion38supports the needles52by sandwiching the needles52between the section384and the member382. The support portion39extends in the front-rear direction and movably supports the needles54. The support portion39has members391and392. The member391has an L shape in a front view, and has a section393that is inclined upward to the left and a section394that is inclined downward to the left from the right end of the section393. The member392has a plate shape that extends in parallel to the section394, and is coupled to the section394. The support portion39supports the needles54by sandwiching the needles54between the section394and the member392.

The support portions48and49extend in the front-rear direction and are provided on the upper surface of the base portion32. The support portion48is provided with members481and482, and movably supports the support portion38between the members481and482. The hole51extends between the members481and482such that it is inclined downward to the right. The support portion48guides the movement of the support portion38. The support portion49is provided with members491and492, and movably supports the support portion39between the members491and492. The hole53extends between the members491and492such that it is inclined downward to the left. The support portion49guides the movement of the support portion39.

The air cylinders35and36are provided on the upper surface side of the base portion32. The air cylinder35moves between the protruding position in which the needles52protrude downward from the hole51of the holding portion33and a retracted position in which the needles52are retracted above the holding portion33. The air cylinder35includes air cylinders351and352that are aligned in the front-rear direction. The air cylinder36moves between the protruding position in which the needles54protrude downward from the hole53of the holding portion33and the retracted position in which the needles54are retracted above the holding portion33. The air cylinder36includes air cylinders361and362that are aligned in the front-rear direction. Each of the air cylinders35and36has a piston (not shown in the drawings) and an urging member (not shown in the drawings) that urges the piston upward. The piston of the air cylinder35is coupled to the needles52via the support portion38. The piston of the air cylinder36is coupled to the needles54via the support portion39.FIG. 6andFIG. 7show the protruding position andFIG. 8andFIG. 9show the retracted position. As shown inFIG. 10, a protruding amount of the needles52and54from the holding portion33in the protruding position is smaller than the thickness of the article9. The protruding amount may be changed in accordance with the thickness of the article9. The air cylinders35and36are connected to an air compressor (not shown in the drawings) via an air tube95. The supply port37(refer toFIG. 10) is provided in the upper surface of the base portion32, communicated with the flow path70, and connected to the air compressor via an air tube (not shown in the drawings). The air tube connected to the supply port37is different from the air tube95connected to the air cylinders35and36.

The control portion80controls the drive of the air cylinders35and36and the supply of the fluid to the flow paths70to78. When a command to move the needles52and54to the protruding position is acquired, the control portion80drives the air cylinders35and36and moves the needles52and54from the retracted position to the protruding position. When a command to prohibit the movement of the needles52and54to the protruding position is acquired, the control portion80drives the air cylinders35and36, maintains the needles52and54in the retracted position, and supplies the fluid to the flow paths70to78.

As shown inFIG. 2, the work table6is a cuboid shaped table that is disposed to the right of the article supply devices4and5. The upper surface of the work table6is substantially horizontal. The height of the upper surface of the work table6is substantially the same as the height of the upper ends of the article supply devices4and5. The PC100is a known computer. The PC100is electrically connected to the article holding device23, the article supply mechanism24and the arm device3, and transmits and receives signals to and from each of the devices.

An electrical configuration of the article holding device23will be explained with reference toFIG. 11. The control portion80of the article holding device23is provided with a CPU81, a ROM82, a RAM83, a communication I/F84and an input/output I/F85. The CPU81, the ROM82and the RAM83are electrically connected to the input/output I/F85via a signal line87. The CPU81performs processing in accordance with various programs stored in the ROM82, and controls the article holding device23. The ROM82stores the various programs including an article supply program, various initial setting parameters and the like. The RAM83temporarily stores calculation results of the CPU81, various data and the like. The communication I/F84is electrically connected to the input/output I/F85. The communication I/F84is an interface for serial communication, for example. The communication I/F84is connected to a communication I/F of the PC100, and the CPU81acquires various commands from the PC100. The communication I/F of the PC100is connected to a communication I/F provided in a control portion of the arm device3, and a communication I/F provided in a control portion of the article supply mechanism24. The control portion80of the article holding device23may directly control the article supply mechanism24.

The input/output I/F85is electrically connected to electromagnetic valves91and92. The electromagnetic valve91is provided in a supply channel of the air that is supplied to the supply port37by the air compressor. The electromagnetic valve92is provided in a supply channel of the air that is supplied to the air cylinders35and36by the air compressor. The CPU81opens and closes the electromagnetic valves91and92, and thus controls the drive and non-drive of the article holding device23.

An overview of the processing performed by the conveyance system1will be explained. In the conveyance system1, the arm device3, and the article holding device23and the article supply mechanism24of the article supply devices4and5work in concert with each other, and convey the uppermost article9placed on the placement table21by the article supply mechanism24to the conveyance position on the work table6. In accordance with a command from the PC100, the arm device3controls the position of the article holding device23in the up-down direction and the horizontal direction. The control portion80of the article holding device23controls the drive of the air cylinders35and36and the supply of the fluid to the flow paths70to78. In accordance with a command from the PC100, the article supply mechanism24moves the placement table21upward.

Article holding processing that is performed by the article holding device23of a first embodiment will be explained with reference toFIG. 12. When the operator inputs a start command to the control portion80via the PC100, the CPU81reads out the article supply program from the ROM82to the RAM83. This processing is performed in a state in which the arm device3disposes the article holding device23in the holding position and the uppermost article9placed on the placement table21is in contact with the holding portion33. When the processing is started, the electromagnetic valves91and92are closed. The start command includes the command as to whether or not to move the needles52and54to the protruding position. When the command to move the needles52and54to the protruding position is acquired, the article holding device23drives the air cylinders35and36, moves the needles52and54from the retracted position to the protruding position, and does not supply the fluid to the flow paths70to78. When the command to prohibit the movement of the needles52and54to the protruding position is acquired, the article holding device23maintains the needles52and54in the retracted position, and supplies the fluid to the flow paths70to78. The operator inputs the command as to whether or not to move the needles52and54to the protruding position to the article holding device23depending on the material of the article9. The input is performed by the operator via the PC100. When the article9easily allows air to pass through, the operator inputs the command to move the needles52and54to the protruding position. When the article9easily allows air to pass through, the material of the article9is a mesh cloth, a sponge cloth, or a cloth with a relatively rough texture. When the article9does not easily allow air to pass through, the operator does not input the command to move the needles52and54to the protruding position. When the article9does not easily allow air to pass through, the material of the article9is a resin sheet cloth or a cloth with a relatively fine texture.

The CPU81acquires the command as to whether or not to move the needles52and54to the protruding position, the command being included in the start command (step S1). The CPU81determines whether or not to move the needles52and54to the protruding position, on the basis of the start command acquired from the PC100at step S1(step S2). When it is determined that the needles52and54are to be moved to the protruding position (yes at step S2), the CPU81switches the electromagnetic valve92from the closed state to the open state, and moves the needles52and54from the retracted position to the protruding position (step S3). When the electromagnetic valve92is open, the air flows to the air cylinders35and36via the air tube95. The air cylinders35and36respectively push the support portions38and39diagonally downward along the extending directions of the holes51and53. As shown inFIG. 6andFIG. 7, the support portions38and39respectively move diagonally downward along the holes51and53. The needles52and54respectively supported by the support portions38and39protrude downward from the horizontal portion331of the holding portion33. The needles52and54pierce the uppermost article9placed on the placement table21, and hold the uppermost article9. The needles52and54are inclined such that the lower the position of the needles52and54, the further they are separated from the center line M. The needles52and54are inclined in mutually opposite directions with respect to the center line M. Therefore, the article holding device23can hold the article9such that the article9is pulled in the left-right direction, and wrinkles are not easily formed on the article9when the article9is held. The CPU81determines whether or not the holding is completed (step S5). As shown inFIG. 14, after moving the article holding device23upward in accordance with the command from the PC100, the arm device3moves the article holding device23to the conveyance position. While the article holding device23is moving from the holding position to the conveyance position, the article holding device23maintains the state of holding one sheet of the article9. The PC100inputs a signal indicating whether or not the article holding device23is in the conveyance position, to the control portion80, on the basis of the signal acquired from the arm device3. When, on the basis of the signal acquired from the PC100, it is determined that the article holding device23is in the conveyance position, the CPU81determines that the holding is completed.

When the holding is not completed (no at step S5), the CPU81returns the processing to step S5. When the holding is completed (yes at step S5), the CPU81switches the electromagnetic valve92from the open state to the closed state, and moves the needles52and54from the protruding position to the retracted position (step S6). When the electromagnetic valve92is closed, the air does not flow to the air cylinders35and36via the air tube95. The piston of each of the air cylinders35and36receives a diagonally upward force of the urging member. As shown inFIG. 8andFIG. 9, the support portions38and39respectively move diagonally upward along the holes51and53. The needles52and54respectively supported by the support portions38and39are retracted above the horizontal portion331of the holding portion33. The needles52and54are removed from the article9, and the article9separates from the holding portion33. The article9is placed on the work table6. Then, the CPU81ends the article holding processing.

When it is determined that the needles52and54should not be moved to the protruding position (no at step S2), the CPU81switches the electromagnetic valve91from the closed state to the open state, and maintains the electromagnetic valve92in the closed state. The CPU81thus maintains the needles52and54in the retracted position, and supplies the fluid to the flow paths70to78(step S8). The air flowing through the flow paths71to78is ejected from the holes61to68along the holding portion33. The air moves along the inclined portions44and45of the holding portion33, between the holding portion33and the uppermost article9. The air ejected from the holes61,63,65and66provided to the front of the recessed portion43and the holes62,64,67and68provided to the rear of the recessed portion43flows away from the center line M (refer toFIG. 6). The holes61,64,65and67, and the holes62,63,66and68are disposed on both sides of the center line M. The air ejected from the holes61to68tends to flow together with the air present in the recessed portion43. Therefore, the recessed portion43tends to have a negative pressure. The article holding device23sucks and holds the uppermost article9using the negative pressure generated between the holding portion33and the uppermost article9placed on the placement table21.

In the same manner as in the processing at step S5, the CPU81determines whether or not the holding is completed (step S9). When the holding is not completed (no at step S9), the CPU81returns the processing to step S9. When the holding is completed (yes at step S9), the CPU81switches the electromagnetic valve91from the open state to the closed state, maintains the electromagnetic valve92in the closed state, and stops the processing that supplies the fluid to the flow paths70to78(step S10). The article holding device23stops the ejection of the air along the holding portion33from the holes61to68of the holding portion33. The article9is placed on the work table6by its own weight. Then, the CPU81ends the article holding processing.

Article holding processing of a second embodiment will be explained with reference toFIG. 13. In the same manner as the article holding device23of the first embodiment, the article holding device23of the second embodiment receives, from the operator, the command as to whether or not to move the needles52and54to the protruding position. When the operator inputs the start command to the control portion80via the PC100, the CPU81reads out the article supply program from the ROM82to the RAM83, and performs this processing. When the processing is started, the electromagnetic valves91and92are closed. The start command includes the command as to whether or not to move the needles52and54to the protruding position. When the command to move the needles52and54to the protruding position is acquired, the article holding device23drives the air cylinders35and36, moves the needles52and54from the retracted position to the protruding position, and supplies the fluid to the flow paths70to78. When the command to prohibit the movement of the needles52and54to the protruding position is acquired, the article holding device23maintains the needles52and54in the retracted position, and supplies the fluid to the flow paths70to78. In summary, the article holding processing of the second embodiment is different from the article holding processing of the first embodiment in that the fluid is supplied to the flow paths70to78when the command to move the needles52and54to the protruding position is acquired.

InFIG. 13, processing that is the same as the article holding processing of the first embodiment inFIG. 12is denoted by the same reference numeral. The article holding processing of the second embodiment is different from the article holding processing of the first embodiment in that processing at step S4is performed between step S3and step S5, and processing at step S7is performed after step S6. Hereinafter, the processing at step S4and the processing at step S7that are different from the first embodiment will be explained and an explanation of the same processing in the first embodiment will be omitted. When it is determined that the needles52and54are to be moved to the protruding position, on the basis of the start command (S1, yes at step S2), the CPU81switches the electromagnetic valve92from the closed state to the open state, and moves the needles52and54from the retracted position to the protruding position (step S3). The CPU81switches the electromagnetic valve91from the closed state to the open state, and supplies the fluid to the flow paths70to78(step S4). The air is ejected from the holes61to68along the holding portion33. The air flows along the inclined portions44and45of the holding portion33, between the holding portion33and the uppermost article9. The air ejected from the holes61,63,65and66provided to the front of the recessed portion43and the holes62,64,67and68provided to the rear of the recessed portion43flows away from the center line M (refer toFIG. 6). The holes61,64,65and67, and the holes62,63,66and68are disposed on both sides of the center line M. The air ejected from the holes61to68tends to flow together with the air present in the recessed portion43. Therefore, the recessed portion43tends to have a negative pressure. The article holding device23can suck and hold the uppermost article9, not only by piercing the article9using the needles52and54that have moved to the protruding position at step S3, but also by using the negative pressure generated between the holding portion33and the uppermost article9placed on the placement table21. The CPU81determines whether or not the holding is completed (step S5). When the holding is completed (yes at step S5), the CPU81switches the electromagnetic valve92from the open state to the closed state, and moves the needles52and54from the protruding position to the retracted position (step S6). The CPU81switches the electromagnetic valve91from the open state to the closed state, and stops the processing that supplies the fluid to the flow paths70to78(step S7). The article holding device23stops the ejection of the air along the holding portion33from the holes61to68of the holding portion33. The article9is placed on the work table6by its own weight. Then, the CPU81ends the article holding processing.

By supplying the fluid to the flow paths70to78, the article holding device23can suck and hold the sheet-like article9, such as a cloth, using the negative pressure generated between the sheet-like article9and the holding portion33. The article holding device23can also hold the sheet-like article9that easily allows air to pass through, by moving the needles52and54to the protruding position and piercing the article9using the needles52and54. Thus, the article holding device23can hold the article9even when the article9is the sheet-like article9which easily allows air to pass through and which is unlikely to be sucked and held because the negative pressure is unlikely to be generated between the article9and the holding portion33.

The needles52and54of the article holding device23of a present aspect are disposed facing each other in a direction parallel to the horizontal plane such that the holes61to68are positioned therebetween. In the article holding device23, the needles52and54are disposed facing each other such that the holes61to68are positioned therebetween. Therefore, in comparison to a device in which the needles52and54are positioned on one side of the holes61to68, or a device in which the single needle52and the single needle54are provided, the sheet-like article9that easily allows air to pass through can be stably held on the holding portion33using the needles52and54.

When the needles52and54of the article holding device23are in the protruding position, the leading end of each of the needles52and54is inclined with respect to the holding portion33in the direction of separating from the holes61to68. As shown inFIG. 7, the leading end of the needle52(522) is inclined diagonally rightward and downward with respect to the holding portion33, and the leading end of the needle54(542) is inclined diagonally leftward and downward with respect to the holding portion33. When the needles52and54pierce the article9, the article holding device23can inhibit the article9from bending. Therefore, in comparison to a device in which the leading end of each of the needles is not inclined with respect to the holding portion in the direction of separating from the holes, the article holding device23can stably hold the sheet-like article9that easily allows air to pass through on the holding portion33, using the needles52and54.

The article holding device23acquires the command as to whether or not to move the needles52and54to the protruding position, via the PC100. The control portion80of the article holding device23controls the drive of the air cylinders35and36and the supply of the fluid to the flow paths70to78. When the command to move the needles52and54to the protruding position is acquired (yes at step S2), the control portion80drives the air cylinders35and36and moves the needles52and54from the retracted position to the protruding position (step S3). When the command to prohibit the movement of the needles52and54to the protruding position is acquired (no at step S2), the control portion80maintains the needles52and54in the retracted position, and supplies the fluid to the flow paths70to78(step S8). The article holding device23can control whether or not to move the needles52and54. When the article9is not held by the needles52and54, the article holding device23maintains the needles52and54in the retracted position. Therefore, the article9is not damaged by the needles52and54. That is, the article holding device23can hold the article9without damage by the needles52and54when the article9is able to be sucked and held by the article holding device23. The article holding device23moves the needles52and54to the protruding position only when the article9is to be held by the needles52and54. It is thus possible to hold the article9by piercing the article9using the needles52and54only when the article9easily allows air to pass through.

The control portion80of the article holding device23of the first embodiment drives the air cylinders35and36, and controls the needles52and54between the retracted position and the protruding position. The control portion80controls the drive of the electromagnetic valve91that switches whether or not to supply the fluid to the flow paths70to78. When the command to move the needles52and54to the protruding position is acquired, the control portion80drives the air cylinders35and36and moves the needles52and54from the retracted position to the protruding position (step S3). When the command to move the needles52and54to the protruding position is acquired, the control portion80does not switch the electromagnetic valve91from the closed state to the open state. When the article9is held by the needles52and54, the article holding device23of the first embodiment need not necessarily supply the fluid to the flow paths70to78.

The control portion80of the article holding device23of the second embodiment drives the air cylinders35and36, and controls the needles52and54between the retracted position and the protruding position. The control portion80controls the drive of the electromagnetic valve91that switches whether or not to supply the fluid to the flow paths70to78. When the command to move the needles52and54to the protruding position is acquired, the control portion80drives the air cylinders35and36and moves the needles52and54from the retracted position to the protruding position (step S3). The control portion80switches the electromagnetic valve91from the closed state to the open state and supplies the fluid to the flow paths70to78(step S4). Therefore, the article holding device23of the second embodiment can supply the fluid to the flow paths70to78regardless of whether or not the article9is to be held using the needles52and54. Therefore, when the article holding device23holds the article9on the holding portion33, it is sufficient that the article holding device23supplies the fluid to the flow paths70to78. Thus, it becomes easy to control the supply of the fluid to the flow paths70to78. When the article holding device23holds the article9on the holding portion33, the fluid ejected from the holes61to68flows between the article9and the holding portion33. Therefore, wrinkles are not easily formed on the article9held by the holding portion33.

The article holding device23is provided with the holes61,62,65and68, the flow paths71,72,75and78, and the recessed portion43. When the article holding device23supplies the fluid to the flow paths71,72,75and78, the fluid is ejected in the first direction from each of the holes61and65, and the fluid is ejected in the second direction from each of the holes62and68. In this manner, the holes61and65and the holes62and68eject the fluid in mutually opposite directions with the recessed portion43positioned therebetween. It is thus possible to effectively generate a negative pressure in the space of the recessed portion43between the holding portion33and the article9, and the article9that faces the holding portion33can be drawn to the recessed portion43side more strongly than in a device that is not provided with the recessed portion43. Therefore, the article holding device23can easily increase the suction power to be larger than that of a known device, and can more reliably suck and hold the sheet-like article9, such as a cloth.

The article holding device23is provided with the holes63,64,66and67, and the flow paths73,74,76and77. Since the article holding device23supplies the fluid to the flow paths71to78, in comparison to a device that supplies the fluid only to the flow paths71,72,75and78, it is possible to more reliably generate a negative pressure in the space of the recessed portion43between the holding portion33and the article9. Thus, the article9that faces the holding portion33can be drawn to the recessed portion43side.

The article holding device23has the first flow path portion41, the second flow path portion42, the first inclined portion44and the second inclined portion45. In the article holding device23, the fluid ejected from the holes61,64,65and67moves along the first inclined portion44and the fluid ejected from the holes62,63,66and68moves along the second inclined portion45, between the holding portion33and the article9. Therefore, in comparison to a device that is not provided with first and second inclined portions, the article holding device23tends to flow the fluid, can more reliably generate a negative pressure in the space of the recessed portion43between the holding portion33and the article9, and can draw the article9that faces the holding portion33to the recessed portion43side.

The article holding device23of the present disclosure can be changed in various ways besides the above-described embodiments. The article holding device23need not necessarily be provided for the article supply devices4and5of the conveyance system1. The article holding device23need not necessarily be detachably mounted on the arm device3. When the article holding device23is mounted on the arm device3, the structure of the arm device3may be changed as appropriate. The structure of the base portion32may be changed as appropriate. The base portion32may have a shape other than a rectangle, such as an elliptical shape in a plan view. The number, the angle of inclination with respect to the holding portion33, and the arrangement etc. of the needles52and54may be changed as appropriate. The needles52and54need not necessarily be disposed facing each other with the holes61to68positioned therebetween. The structure and arrangement of the support portions38,39,48and49that support the needles52and54may be changed as appropriate. The needles52and54may be inclined with respect to the holding portion33in a direction in which the leading end of each of the needles52and54are closer to the holes61to68. The leading end of each of the needles52and54may be directed diagonally downward in the front-rear direction. In this case, the support portions38and39may extend in the front-rear direction and may movably support the needles52and54.

In the second embodiment, the electromagnetic valve91may be communicated not only with the supply port37but also with the air cylinders35and36, and the control portion80may perform the processing that supplies the fluid to the flow paths and the processing that controls the positions of the needles at the same timing. It is sufficient that the holes61to68be provided such that the fluid can be supplied along the holding portion33. The number, arrangement, direction with respect to the flow paths, and size etc. of the holes may be changed as appropriate. The holes of the article holding device may be the hole61and the hole62only. The holes of the article holding device may be at least one of the holes61and65and at least one of the holes62and68. In order to effectively generate a negative pressure in the recessed portion43, in the article holding device, it is preferable that the first hole be provided in the vicinity of a boundary between the recessed portion43and the first flow path portion41, in comparison to when the first hole is provided in a position separated from the boundary. In the article holding device, it is preferable that the second hole be provided in the vicinity of the boundary between the recessed portion43and the second flow path portion42, in comparison to when the second hole is provided in a position separated from the boundary. For example, regarding the holes of the article holding device, it is preferable to provide the holes61and62only, in comparison to when the holes65and68only are provided. The holes of the article holding device may be the holes61,62,63and64only, or may be the holes65,66,67and68only. The flow paths may be changed as appropriate in accordance with the number, shape, size and arrangement of the holes. The flow paths of the article holding device may be at least one of the flow paths71and75and at least one of the flow paths72and78. The first flow path and the second flow path of the article holding device may have different supply ports to supply the fluid. The flow paths of the article holding device may be the flow paths71,72,73and74only. The holding portion33of the article holding device23need not necessarily include all or some of the first flow path portion41, the recessed portion43, the second flow path portion42, the first inclined portion44and the second inclined portion45. The shapes, sizes and arrangement etc. of the horizontal portion331, the first flow path portion41, the recessed portion43, the second flow path portion42, the first inclined portion44and the second inclined portion45may be changed as appropriate. The recessed portion43may be recessed upward in a hemispherical shape.

It is sufficient that an article holding program to execute the article holding processing inFIG. 12andFIG. 13may be stored in a storage device provided in the article holding device23until the article holding device23executes the program. The acquisition method and acquisition route of the program and each of the storage devices that store the program may be changed as appropriate. The article supply device4may receive the program to be executed by a processor, from other devices via a cable or wireless communication, and may store the received program in the storage device. The other devices include, for example, a PC and a server that is connected via a network. The storage device provided in the article holding device23may be a storage device, such as a HDD or a SSD.

Each of the steps of the article holding processing inFIG. 12andFIG. 13is not limited to the example in which the CPU81performs each of the steps, and another electronic device (an ASIC, for example) may perform part or all of the processing. Each of the steps of the above-described processing may be distributed and processed by a plurality of electronic devices (a plurality of CPUs, for example). Each of the steps of the article holding processing of the above-described embodiments may be changed in order, omitted or added, if necessary. The present disclosure (invention) also includes an aspect in which an OS or the like working on the article holding device23performs part or all of the actual processing in accordance with a command from the processor of the article holding device23and realizes the functions of the above-described embodiments. The control portion80may acquire the material of the article as the command as to whether or not to move the needles to the protruding position. In this case, the control portion80may store, in advance, a list of the materials that easily allow air to pass through and may determine whether the material of the acquired article easily allows air to pass through. The control portion80may move the needles to the protruding position when the material of the acquired article easily allows air to pass through, and may maintain the needles in the retracted position when the material of the article does not easily allow air to pass through. The control portion80may read a radio frequency identification (RFID) or the like assigned to the article or the placement table21, and may acquire the command as to whether or not to move the needles to the protruding position. The control portion80may control the article supply mechanism24.