SE1650191A1 - Gripping device - Google Patents

Abstract

The present invention relates to a gripping device (1) comprising an attachment part (8), a core member (2), an inflatable gripping sleeve (3), a conically shaped guide member (4), said inflatable gripping sleeve (3) being arranged around said core member (2), said core member (2) defining a first passageway (20) in communication with the interior of said gripping sleeve (3) for provision of compressed air thereto wherein said inflatable gripping sleeve (3) being detachably attached to said core member (2) and clamped thereto by an axial clamping force acting upon an outer end (32) and an inner end (33) of said gripping sleeve (3).

Description

GRIPPING DEVICE TECHNICAL FIELD The present invention relates to a gripping device comprising an attachment part, a coremember, an inflatable gripping sleeve, a conically shaped guide member, said inflatablegripping sleeve being arranged around said core member, said core member defining afirst passageWay in communication With the interior of said gripping sleeve for provision of compressed air thereto.

STATE OF THE ART Inflatable gripping devices are used as an altemative to conventional multifingeredclaws and vacuum cups in robotic or mechanical pick-and-place systems (a process ofpicking parts up and placing them in new locations), particularly in so-called bin-picking. Bin-picking enables a robot to automatically move a number of randomlyplaced parts regardless of their orientation. It uses a plurality of sensors and cameras forstereoscopic vision. The standard application moves one part in any orientation Whetherloosely or tightly packed, either on the floor, conveyor, bin or container, the parts can bein any orientation. The inflatable gripping device is attached to the outer end of therobot arm and is inserted inside a product and inflated against the interior by means offriction and pressure from the sleeve against the interior of the goods, the object may be picked.

The document US 5449182 describes a universal substrate holding apparatuscomprising: a first core member having a top end and a bottom end; a first inflatabletube disposed around the first core member; a first passageway defined by the first coremember in communication With the interior surface of the first tube; a second coremember having a top end and a bottom end, a portion of the second core memberhaving a larger outer cross-sectional dimension than the first core member, Wherein thetop end of the first member is associated With the bottom end of the second member; asecond inflatable tube disposed around the second core member, a portion of the secondtube having a larger outer cross-sectional dimension than the first tube, and Whereby thesecond tube is disposed in tandem With the first tube; and a second passageway definedby the second core member in communication With the interior surface of the secondtube.

The document JP 2009-050993 describes a chucking device that comprises a base body and a rubber sleeve disposed on the outer periphery of the base body. The rubber sleeve is inflated by supplying air into an air tight chamber forrned between the base body andthe rubber sleeve. At both ends of the rubber sleeve, bead sections are forrned to embeda bead Wire around all circumferences, and on the base body bearing surfaces are formed so as to abut against all the circumferences of the bead sections.

Since a bin-picking system should be able to be unmanned for many hours the grippingdevice must be reliable and durable. Inflatable gripping devices available today areeither too large and clumsy, or they last only a few hours because the sleeve becomes Wom and breaks.

BRIEF DESCRIPTION OF THE INVENTIONIt is an object of the present invention to eliminate or at least minimize the abovementioned problems, Which is achieved by means of a gripping device according to claim l.

Thanks to the invention, a gripping device is provided Where all or some of the partseasily and quickly may be replaced When they become Wom or if the size needs to be changed.

According to one aspect of the invention the gripping device comprises a core memberthat supports a gripping sleeve at both an outer and an inner end of the gripping sleeveWhich gives the advantage that the gripping sleeve Will not be so quickly Wom and thus may last longer in use, getting a longer lifetime.

According to another aspect of the invention, the core member comprises an inner partand an outer part and said inner part comprises an inner cylindrical lip and said outerpart comprises an outer cylindrical lip and the gripping sleeve is easily arranged around these lips.

According to still another aspect of the invention the head of the core membercomprises a concave portion provided With an outlet for compressed air. Thanks to theconcave portion the Weight of the core member is minimized. The risk of the corebumping into the objects to be picked during insertion and retraction is also minimizedWhich in tum minimizes the Wear of the sleeve. Furthermore, the outlet for compressedair being placed in the concave portion secures an efficient discharge of compressed air from the sealing room.

According to another aspect of the invention, the gripping device comprises a guidemember, which preferably is conically shaped and guides the gripping device into thegoods to be picked and where the guide member is arranged in the outer end of thegripping device and gets into contact with the goods first, thereby protecting and preventing the gripping sleeve to get wom.

According to one aspect of the invention the gripping sleeve comprises an outer and aninner end, both ends comprising an annular portion extending radially inwards, towardsa circular opening. Said annular portion comprises a cylindrical edge extending in anaxial direction from the annular portion into the interior of the gripping sleeve. Thegripping sleeve is arranged around the cylindrical lips of the core member. The annularportions and the cylindrical edges are dimensioned to have a snug fit around thecylindrical lips of the core member. When assembled, the diameter of the guide memberis the same, but preferably larger, than the diameter of gripping sleeve in uninflatedstate in order to protect the gripping sleeve during insertion into the goods and in order to clamp the gripping sleeve against the head of the core member in a preferred way.

According to another aspect of the invention, the gripping device comprises a washer.When assembled, the diameter of the washer is the same, or slightly larger than thediameter of the gripping sleeve in uninflated state in order to protect the gripping sleeveduring retraction out of the goods and in order to clamp the gripping sleeve against thehead of the core member in a preferred way.

BRIEF DESCRIPTION OF FIGURESIn the following, the invention will be described in greater detail with reference to theattached figures of the drawings, in which: Fig. 1 illustrates a side view of a gripping device according to the invention, Fig. 2 illustrates an assembly drawing of the gripping device l, Fig. 3 illustrates a perspective view of a guide member according to theinvention, Fig. 4 illustrates a perspective view of a core member according to the invention, Fig. 5 illustrates a cross sectional view of a core member according to theinvention, Fig. 6 illustrates a cross sectional view across the line B-B in figure 5, of agripping device according to the invention, Fig. 7 illustrates a perspective view of a sleeve according to the invention, Fig. 8 illustrates a cross sectional view of a sleeve according to the invention,andFig. 9 illustrates a cross sectional view across the line A-A in figure l, of a gripping device according to the invention.

DETAILED DESCRIPTION OF FIGURES The following detailed description, and the examples contained therein, are provided forthe purpose of describing and illustrating certain embodiments of the invention only andare not intended to limit the scope of the invention in any way. By the terrn compressedair or air any kind of fluid suitable for the purpose is comprised, unless otherwiseindicated. Parts that in the description are defined by the terrn “inner” aredirected/arranged/extending towards the attachment part of the robot while parts that aredefined by the terrn “outer” are directed/arranged/extending outwardly, away from theattachment part of the robot. These terms are not intended to limit the scope of the invention in any way but are provided for a more easy understanding of the description.

Figure l illustrates a side view of a gripping device l according to a preferredembodiment of the invention. The gripping device l comprises, from left to right in thefigure, an attachment part 8, a washer 5, an inflatable gripping sleeve 3 and a guidemember 4 which preferably is conically shaped. The dashed lines illustrate the interiorof the gripping device l including a core member 2.

Figure 2 illustrates an assembly drawing of the gripping device l. From left to right inthe figure is seen the attachment part 8 having an inlet/radial bore 800 for provision ofcompressed air to intemal air channels, see f1g. 9. In an outer end face of the attachmentpart 8 attachment means are arranged which comprise a cylindrical recess 85 forcoupling the core member 2 to the attachment part 8. At a bottom 900 in the recess 85,the outlet 84 for one of the air channels 80b is visible. Outside the face end of theattachment part is arranged the washer 5, a sealing l0 arranged in a groove 240 on thecore member 2, the gripping sleeve 3 and the guide member 4. The core member isinserted into the washer 5 and further into the recess 85. The gripping sleeve 3 isarranged around the core member 2. A screw, see fig. 9, is used to attach the differentparts to each other via an axial passageway 20 aligned with the longitudinal axis in thefigure. The passageway 20 is formed by central bores in the attachment part 8, the coremember 2 and the guide member 4.

Figure 3 illustrates a perspective view of a guide member 4 according to the invention.

In a preferred embodiment the guide member 4 comprises an inner end 40 and an outer end 42 and a peripheral surface forrning a guiding portion 41 there between. Theguiding portion 41 is gradually tapered towards the narrower outer end 42. Preferably,the guiding portion 41 is conical but the skilled person realize that the guiding portion41 may have other tapered shapes. However, the shape is preferably symmetrical about the longitudinal axis.

Figure 4 illustrates a perspective view of a core member 2 according to the invention.The core member 2 comprises a cylindrical pipe 241 having an outer head portion 25and an inner arm portion 24, said pipe 241 def1ning a second portion 201 and a thirdportion 202 of the axial passageway 20. Radial channels 23 extend from the secondpassageway portion 201 to the outside of the head portion 25. The arm portion 24 isdirected inwards and arranged to be attached to the attachment part 8 via the attachmentmeans. The head portion 25 is directed outwards and arranged to hold the grippingsleeve 3 and the guide member 4. The gripping sleeve 3 is arranged around the headportion 25, see f1g. 9. The head portion 25 comprise inner and outer cylindrical ends252, 253 and a concave portion 250, 251 arranged there between. For cost reasons, thecore member 2 is preferably made in metal although it may also be made in plastic.Metal is preferable also for strength reasons, in that machining is easier and in a betterresistance to chemicals, among other reasons. The core member is preferablymanufactured as one integrated part for cost reasons, e.g. by tuming, but may of course also be made of several parts.

Figure 5 illustrates a cross sectional view in the longitudinal direction of a core member2 according to the invention. In the arm portion 24, the inner end 242 of the cylindricalpipe 241 comprises an outside circumferential groove 240, suitable for a seal 10, seeFig. 9, typically an O-ring or similar. The length of said arm portion 24 is adapted to thedepth of the cylindrical recess 85 in the attachment part 8 and the thickness of thewasher 5. As can be seen in f1g. 9, the depth of the cylindrical recess 85 shall besufficient for providing space for the seal 10 which acts against the inside wall of thecylindrical recess 85. The outer diameter D of the cylindrical pipe 241 is adapted to thediameter of the cylindrical recess 85 such that a snug fit is achieved upon entry of thecylindrical pipe 241 into the cylindrical recess 85 when the gripping device l isassembled. Hence, the core member 2 is supported by the cylindrical wall andpositioned axially in the cylindrical recess 85. The outer diameter D of the arm portion24 is in the interval 5-200 mm, preferably in the interval 10-150 mm and more preferred in the interval 20-90 mm.

In the head portion 25, the cylindrical pipe 241 comprises a protruding collar 256 at itsouter end with a stepped axial recess which serves to hold the guide member 4 andwhich also forms an inlet 257 to the third passageway portion 202. The head portion 25further comprises inner and outer cylindrical portions forrning a respective protrudinglip 252, 253 extending in the axial direction. A waist portion 254, formed by a firstinwardly conical part 251 and a mirrored second outwardly conical part 250, extendsthere between. Discharge openings from the radial channels 23 are arranged in the waistportion. The core member 2 has a greatest width W” in the area of the inner and outerprotruding lips 252, 253. The collar 256 extends outside the outer protruding lip 253 ina forward direction such that there is a level difference q between their end faces.Radially inside the respective protruding lips 252, 253 there is a circular groove 244,255. The grooves 244, 255 encircle the cylindrical pipe 24l and the collar 256respectively. The cylindrical lips and the grooves cooperate with the end portions of thegripping sleeve 3 such that the gripping sleeve is detachably fixed to the head portion ina firm and airtight manner, which will be further described in connection to fig. 8 andf1g 9.

The second passageway portion 201 have a diameter d1 that is larger than the diameterdz of the third passageway portion 202. The diameter d1 of the second passagewayportion 20l is also larger than the diameter d4 of the screw 9 in order to create a gap 90between the outer periphery of the screw 9 and the inner wall of the second passagewayportion 20l, best seen in Fig. 9. This gap 90 is arranged to let the compressed air flow toand from the air channels 80a, 80b in the attachment part 8, via the gap 90 along thescrew 9 in the second passageway portion 20l and further via the radial channels 23 tothe inflatable sealing room 36 for inflation and deflation of the gripping sleeve 3. Theradial channels 23 are arranged in the waist portion 254 between the first conical part25l and the second conical part 250. They extend radially between the gap 90 and thesealing room 36 which is arranged outside the head portion 25 of the core member,between the periphery of the core member 2 and the inside wall of the gripping sleeve 3.The inlet to the radial channels are preferably arranged in the zone where the secondpassageway portion 20l and the third passageway portion 202 meet although the inletmay be arranged elsewhere along the gap 90 in the head portion 25. The outlet of theradial channels 23 are preferably arranged in the very waist thus securing an efficientdischarge of compressed air from the sealing room 36, best understood from figure 5.

Figure 6 illustrates a cross sectional view of the core member 2 across the line B-B infigure 5 and shows the radial channels 23 which extend from the second passagewayportion 20l to the waist portion outside of the head 25.

Figure 7 and 8 illustrates a gripping sleeve 3 in a preferred embodiment according to theinvention. In the preferred embodiment the gripping sleeve 3 is symmetrical both inlongitudinal and transversal direction. The gripping sleeve 3 is preferably made of anelastic material with adequate fatigue strength and wear resistance, in particular abrasivewear resistance. Examples of suitable materials are rubber, silicone or polyurethane.Norrnally, the gripping device is used at temperatures around room temperature but theskilled person understands that the sleeve material shall be adapted to the actualworking temperature and selected in order to obtain the required properties. Thegripping sleeve 3 comprises a cylindrical wall 31 with partially closed ends 32, 33 in theform of an outer annular portion 320 and an inner annular portion 330 extendingradially inwards. Norrnally a gripping device of this type is used for picking small tomedium sized objects, i.e. objects with a weight in the range of 0 - 30 kg or at least inthe rage of 0 - 20 kg. Larger objects are norrnally easy to handle as they are larger andtherefore easier to grip. For obvious reasons best performance is obtained if the size ofthe gripping sleeve 3 is adapted to the objects to be picked. The outer diameter H of thegripping sleeve 3 is in the interval 10-200 mm, preferably in the interval 15-150 mmand more preferred in the interval 20-100 mm. The cylindrical wall 31 has a thickness Tin the interval 0.5-15 mm, preferably in the interval 1-10 mm and more preferred in theinterval 1.5-5 mm. The outer annular portion 320 surrounds an outer circular opening34. The wall thickness t of the outer annular portion 320 is at least as thick as the leveldifference q between the collar 256 and the outer cylindrical lip 253 of the coremember°s head 25, preferably somewhat thicker, in order to enable that the outerannular portion 320 is clamped between a back side 404 of the guide member 4 and theprotruding lip 253 when assembled. In a preferred embodiment the outer annularportion 320 has an outer cylindrical edge 321 which protrudes toward the sleeve°sinterior. The outer cylindrical edge 321 extends from the annular portion 320 into thegripping sleeve 3 in an axial direction of said gripping sleeve 3. The opposite end of thegripping sleeve 3, i.e. the inner end 33, is reversed towards the outer end 32. The innerend 33 also comprises an inner annular portion 330 surrounding an inner circularopening 35. The inner annular portion 330 ends with an inner cylindrical edge 331around the opening 35. The inner cylindrical edge 331 extends from the annular portion330 into the gripping sleeve 3 in an axial direction of said gripping sleeve in reverseddirection compared with the outer cylindrical edge 321 at the outer end 32. The innerend 33 of the gripping sleeve 3 is clamped between the washer 5 and the innerprotruding lip 252 of the core member 2 when the screw 9 is tightened upon assemblyof the gripping device. The gripping sleeve 3 may have a diameter that is smaller, larger than or as wide as the attachment part 8 but the diameter of the washer 5, the guide member 4 and the core member 2 follows the outer diameter H of the gripping sleeve 3.The guide member 4 may have a diameter W that is the same as the outer diameter H ofthe gripping sleeve 3 or wider. Preferably, the washer 5 has a diameter as wide or wideras the diameter H of the gripping sleeve 3. The greatest width W” of the core member 2is adapted to the thickness T of the gripping sleeve 3, such that the gripping sleeve 3 issupported from inside by the core member 2 but still obtains an overall diameter H inassembled state which is smaller than the diameter W of the guide member 4, typicallyin the order of a few millimeters smaller than the diameter W of the guide member 4.

Figure 9 illustrates a cross sectional view through the line A-A of the gripping device lin assembled state. The gripping device comprises an axial passageway 20 along alongitudinal axis B. The attachment part 8 comprises a hollow shaft defining a firstportion 82 of an axial passageway 20. The core member 2 comprises secondpassageway portion 20l and third passageway portion 202. The guide member 4comprises a fourth 40l and a f1fth 402 portion of the axial passageway 20. The secondto f1fth portions of the passageway 20 form a mounting bore 6 arranged concentricallyalong the longitudinal axis B. The inner end of the attachment part 8, see f1g 2, isarranged at a robot arm in a manner known per se and the outer end is provided withattachment means for attaching the other parts of the gripping device l. It shall beunderstood that the attachment part 8 may be an integrated part of the outer end of therobot arm itself and need not be a separate part which is attached to the robot arm. Theattachment means comprises a cylindrical recess 85 at the outer end face of theattachment part 8 for coupling, preferably demountable, the core member 2 to theattachment part. The cylindrical recess 85 is axially aligned with the first passagewayportion 82. At its outer end, adjacent the cylindrical recess 85, the first passagewayportion 82 is provided with a threaded portion 8 l.

When the gripping device l is in assembled state the axial mounting bore 6 aligns withthe first passageway portion 82 in the attachment part 8. The washer, core member andguide member 4 are detachably attached to the attachment part 8 and to each other by ascrew 9, see Fig. 9, or other suitable fixing means, inserted into the mounting bore 6 andengaged with the threaded portion 8l. The inflatable gripping sleeve 3 is arrangedoutside a head portion 25, see fig 5, of the core member 2 and clamped at its inner endbetween the core member 2 and the washer 5 and at its outer end between the coremember 2 and the guide member 4. The first passageway portion 82 and the axialmounting bore 6 communicates with air channels 80a, 80b, 23 in the attachment part 8and the core 2 respectively for provision of compressed air in the gripping device l.

Since the parts of the gripping device l are detachably attached to each other by thescrew (or the like), it is easy to assemble or disassemble the gripping device l, forinstance if any part is wom and needs to be replaced. An improvement is also obtainedin that it is convenient to substitute one gripping device (or parts thereof) for another ina different size if differently sized objects are to be picked up from different batches.When assembling the gripping device l, the core member 2 is inserted into the grippingsleeve 3 and the inner cylindrical edge 33l is slipped around the inner protruding lip252 and into the inner circular groove 244 of the core member and the outer cylindricaledge 32l is slipped around the outer protruding lip 253 and into the outer circulargroove 255 of the core member so that the gripping sleeve 3 is arranged around the coremember 2 in a snug fit. In a bridging area between the outer and inner cylindrical edge32l, 33l and the outer and inner annular portion 320, 330 respectively, an outsidesurface is formed with a right angled edge. The right angled edge is positioned wherethe cylindrical surface surrounding the opening 34, 35 and the radially extendingsurface of the outer and inner annular portion 320, 330 meet. The inside surface of theouter cylindrical edge 32l is preferably rounded. The outer cylindrical lip 253preferably has a correspondingly rounded edge in order to reduce wear on thecylindrical edge 32l. Letting the cylindrical edges 32l, 33l extend into the circulargrooves 244, 255 reduces the risk that the guide sleeve is pulled off the core in case theguide sleeve 3 is overinflated. This effect is pronounced due to the increased wallthickness in the bridging area. The washer 5 is slipped on to the arm portion 24 of thecore member 2. A seal l0 is arranged in the circumferential outer groove 240 of the armportion 24 and the arm is inserted into the recess 85 of the attachment part 8. The seall0 ensures an airtight mounting so that no compressed air seeps out when the grippingsleeve 3 is inflated. In next step the guide member 4 is arranged at the head portion 25of the core member 2 and the screw 9 is inserted into the common mounting bore 6 thatextends through the guide member 4, the core member 2 and into the attachment part 8.The screw 9 is threaded into a threaded part 81 inside the attachment part 8 andtightened to a predeterrnined clamping force, for example by the aid of a torque wrench.Thereby, the sleeve is clamped between the inner protruding lip 252 and the washer 5 atthe inner end and between the outer protruding lip 253 and the guide member°s backside 404 at the outer end. As the skilled person will understand, the elasticity ofgripping sleeve 3 can be varied and the pressure of the compressed air and the clampingforce can be adapted accordingly. Thereby, objects with different weights may behandled while still maintaining an airtight clamping of the protruding lips 252, 253. Theclamping force shall however not be so strong that the gripping sleeve 3 may explode in case of too high air pressure. Instead, the clamping force shall perrnit compressed air at a certain pressure to escape via the clamping gap 252a, 253a between the protruding lips252, 253 and the washer 5 and back side 404 respectively. In order to be able to vary theclamping force the length of the arrn portion 24 and/or the thickness of the washer 5 ischosen so that the end face of the arrn portion 24 does not reach the bottom of thecylindrical recess 85. Thus, a gap 86 between the bottom surface 900 and the inner endface of the arrn portion 24 is obtained which also serves as a communication gap 86 forthe compressed air.

The width W of the inner end 40 of the guide member 4 preferably is as wide as thegripping sleeve 3 in the uninflated state, or wider. In the preferred embodiment thewidth W is some few millimeters wider, typically l-2 mm wider, than the width of thegripping sleeve 3 giving the advantage that the guide member 4 protects the grippingsleeve 3, and particularly the outer end 32 of the gripping sleeve, see Fig. 8, when thegripping device 1 is inserted into the interior of the object to be picked. The guidingportion 4l further makes it easier to insert the gripping device l into the interior of thegoods to be picked /handled. The fourth 401 and fifth 402 passageway portions in theguide member 4 comprises a through bore 43 for the fastening screw 9. The fifthpassageway portion 402 in the outer end of the through bore 43 forms a countersink 402for the head 900 of the screw 9, thus avoiding the head 900 to extend outside the outerend 42 of the guide member 4. A stepped transition between the countersink 402 andthe inner, narrower fourth passageway portion 40l of the through bore 43 forms anabutment surface 403 for the head 900 of the screw 9. The screw 9 extends from theouter end of the guide member 4, through the core member 2 and into engagement withthe threaded portion 8l in the first passageway portion 82 in the attachment part 8.

The guiding sleeve 405 engages with the collar 256 of the core member 2. The collar256 forms a stepped axial recess into which a guiding sleeve 405 of the guide member 4is inserted in a tight fit with respect to the width and preferably also with respect to thedepth of the guiding sleeve 405. The stepped axial recess also forms an inlet 257 to thethird passageway portion 202. The depth of the inlet 257 is adapted to the height of theguiding sleeve 405 such that the back side 404 of the guide member 4 abuts the outwardfacing end 258, which preferably is substantially flat, of the collar 256 when assembled.The guiding sleeve 405 acts like a guide for the guide member 4 in the radial directionwhen to be assembled with the core member 2. The guiding sleeve 405 extends aroundthe opening of the fourth passageway portion 40l at the back of the guide member 4.The back side 404 radially outside the guiding sleeve 405 is preferably substantiallyflat. The inner diameter dg of the guiding sleeve 405 is preferably the same as the inner diameter d; of the third passageway portion 202. In order to prevent air leakage and 11 axial alignment between these parts, the diameter d4 of the screw 9 is preferably thesame (theoretically) as the inner diameter d; of the third passageway portion 202. Atolerance in the order of H6 or H7 between the two is desired. The third passagewayportion 202 has a diameter that is less wide than the diameter of the inlet 257. The thirdpassageway portion 202 has a diameter that is the same as the diameter on the screw 9.If desired, a seal, conventionally an O-ring, may be arranged at the bottom of the recessinto which the guiding sleeve 405 of the guide member 4 is inserted for furtherincreasing the safety against air leakage.

Thanks to this invention a gripping device 1 is provided where the guide member 4guides the gripping device 1 into the piece to be picked up and where the guide member4 gets into contact with the goods before the gripping sleeve 3 does, thereby preventingthat the gripping sleeve 3 gets wom. The guide member 4 is, at the widest part that isarranged to abut the gripping sleeve 3, preferably as wide as the diameter H of thegripping sleeve 3 or wider giving the advantage that the guide member 4 instead of thegripping sleeve 3 strikes into the goods to be picked when the gripping device 1 isseeking its way into the goods. Thereby, the gripping sleeve 3 will get a longer lifetime.The same protecting principle applies also to the washer. The washer 5 is a standardcircular washer with a diameter preferably as wide as the diameter H of the grippingsleeve 3 in order to clamp the gripping sleeve 3 against the core member 2 in an optimalway and to protect the inner edge of the gripping sleeve 3 when retracting the grippingdevice 1 from the device that has been handled. If the washer 5 has a wider diameterthan the diameter H of the gripping sleeve 3 there is also a risk that the washer 5 getshooked into details of the goods when inserting or retracting the gripping device 1 intoor out from the goods, but it is a possible modif1cation although not preferred. Thegripping device 1 according to the invention provides a gripping sleeve 3 that is moreprotected against wear and the risk that the gripping sleeve 3 will be hooked into detailsof the goods is minimized. Also, the new configuration of the edges of the grippingsleeve and the head of the core member provides a new way of clamping the grippingsleeve to the core member resulting in less wear of the guiding sleeve upon inflation inthe region where it is clamped to the core compared to bin-picking sleeves according toprior art which are subjected to sharp bending in the area where it is clamped wheninflated.

Thanks to the invention, the gripping sleeve 3 may also be easily replaced by a new one which will result in cost savings. 12 The gripping device 1 works in a conventional manner by inflation and deflation of thegripping sleeve 3. In this embodiment, compressed air is used to expand the grippingsleeve 3. For provision of compressed air to the gripping sleeve 3, the first passagewayportion 82 may be used. Existing air used for maneuvering the robot arrn may beprovided for instance through a sealed coupling at the inner end of the attachment part8. At least one but in this embodiment two air channels 80a, 80b are arranged,preferably diametrically, alongside the first passageway portion 82 in the wall of theshaft. The attachment part 8 further comprise a channel 83 between the first passagewayportion 82 and the respective air channels 80a, 80b. For ease of manufacture, a radialbore 83 is made from one side of the shaft in order to join the first passageway portion82 with the respective air channels 80a, 80b. The channel 83 runs through the shaftwall, through the closest air channel 80a, through the first passageway portion 82 andinto the opposite air channel 80b and forms a radial channel 83 between them. Thechannel°s inlet 800 in the shaft wall is then plugged. From the first passageway portion82 the compressed air flows, via the radial channel 83, into the two air channels. The airchannels 80a, 80b has a respective outlet 84 for compressed air at the bottom of thecylindrical recess 85. The compressed air flows via the communication gap 86 into thegap 90 outside the screw 9 in the second passageway portion 201, through the radialchannels 23 and into the sealing room 36 for inflation of the gripping sleeve 3. Upondeflation the compressed air flows the opposite way. As a safety measure in order toavoid rupture of the gripping sleeve and possible damage to the device to be picked,compressed air is allowed to escape via the inner clamping gap 252a where the innercylindrical edge 331 is slipped around the inner protruding lip 252 and via the outerclamping gap 253a where the outer cylindrical edge 321 is slipped around the outerprotruding lip 253 in case of overpressure in the sealing room 36.

ALTERNATIVE EMBODIMENTS The invention is not limited by what has been described hereinabove, but can be variedwithin the scope of the following claims. For instance, it will be appreciated that thedifferent parts in the gripping device may be manufactured in different dimensionsdepending on the goods that will be picked. The gripping device is controlled by meansof pneumatics and by adjusting the pressure to the gripping sleeve the gripping forcewill be adjusted. The number of radial channels in the core member may of course varyand be both more and fewer in number than described in the description. The head ofcore member need not have a convex portion but may be cylindrical although the skilledperson understands that the described benefits will not be obtained. Also, the radial channels in the head of the core member may be arranged differently. They may be 13 fewer or more, they need not be evenly spaced or extend in radial direction. The circulargrooves of the core member may be omitted or forrned in another fashion. For provisionof compressed air it is also conceivable to arrange a nozzle from an extemal source ofcompressed air at the inlet of the channel. It is also conceivable to have radial boresfrom opposite sides of the shaft for provision of compressed air into the respective airchannel in Which case the radial bore/bores doesn°t have to pass into the firstpassageway portion. The same goes for the embodiment With only one air channel incase the bore serves as an inlet for compressed air. The screw may be provided With acentral bore and a radial channel/channels Which communicates With the radial channels in the head portion of the core member.

Claims (1)

1. A gripping device (1) comprising an attachment part (8), a core member (2), aninflatable gripping sleeve (3), a conically shaped guide member (4), saidinflatable gripping sleeve (3) being arranged around said core member (2), saidcore member (2) def1ning a first passageway (20) in communication with theinterior of said gripping sleeve (3) for provision of compressed air theretocharacterized in that said inflatable gripping sleeve (3) being detachablyattached to said core member (2) and clamped thereto by an axial clamping force acting upon an outer end (32) and an inner end (33) of said gripping sleeve (3). A gripping device (1) according to claim 1, characterized in that said coremember (2) comprise an inner cylindrical end portion (252) and an outercylindrical end portion (253) and a concave portion (250, 251, 254) there between. . A gripping device (1) according to claim 2, characterized in that said end portions (252, 253) comprise an inner and outer protruding lip (252, 253) whichsupports said sleeve (3) at its inner (33) and outer ends (32). A gripping device (1) according to claim 3, characterized in an inner radialclamping gap (252a) between the inner protruding lip (252) and a washer (5) andan outer (253a) radial clamping gap between an outer protruding lip (253) and aguide member (4). . A gripping device (1) according to claim 1, characterized in that said clamping force is exerted by an attachment screw (9) acting upon said guide member (4)and running in an axial passageway (20) through said core member (3) andfurther into the attachment part (8). A gripping device (1) according to claim 1, characterized in that the attachmentpart (8) comprises a recess (85) arranged to receive an arm portion (24) of thecore member (8). A gripping device (1) according to claim 6, characterized in that a length of thearm portion (24) and/or a thickness of the washer (5) is adapted to a depth of the 10. recess (85) so that a communication gap (86) for an inflation medium is obtainedbetween a bottom surface (900) of the recess (85) and an inner end face of thearm portion (24) upon tightening of the attachment screw (9) to a predeterrnined clamping force. A gripping device (1) according to claim 7, characterized in that a secondpassageway portion (201) of said passageway (20) comprise a gap (90) for theinflation medium Which gap (90) communicates With said communication gap(86) and at least one channel (23) having a discharge opening (23a) in theconcave portion (250, 251, 254). A gripping device (1) according to claim 8, characterized in that said air gap (90) is arranged alongside the attachment screW (9). A gripping device according to claim 1, characterized in that said guidemember (4) has a Width (W) that preferably is at least as Wide as a diameter (H)of said sleeve (3) in its uninflated state.