Patent Publication Number: US-2022227599-A1

Title: End effector

Description:
BACKGROUND 
     1. Technical Field 
     The present disclosure relates to an end effector. 
     2. Description of the Related Art 
     Patent Literature (PTL) 1 describes a method in which a film attached onto an adhesive sheet of a workpiece held at a predetermined position by the hand of one arm of a dual arm robot as an articulated robot is peeled off from the adhesive sheet by the hand of the other arm of the dual arm robot, and the workpiece is attached to a predetermined region by the hand of the one arm of the dual arm robot. 
     PTL 1 is Japanese Patent No. 5914308. 
     SUMMARY 
     An object of the present disclosure is to provide an end effector that can peel off release paper. 
     The present disclosure is an end effector that is connectable to a robot arm for peeling off release paper and includes a housing including a guide groove having a start position S, an intermediate position M, and an end position E and a rotary unit including a needle and a first support movable along the guide groove. There is provided an end effector that satisfies θ 1 &lt;θ 2 &lt;θ 1 +180° when it is assumed that a line segment connecting the start position S and the intermediate position M is defined as a line segment SM, a line segment connecting the intermediate position M and the end position E is defined as a line segment ME, an angle formed between the line segment SM and a horizontal direction when the end effector is placed on a floor surface is defined as θ 1 , and an angle formed between the line segment SM and the line segment ME is defined as θ 2 . This makes it possible to peel off the release paper using the end effector. 
     The present disclosure can provide an end effector that can peel off release paper. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view illustrating an appearance structure of end effector  1  according to one aspect of the present disclosure. 
         FIG. 2  is an exploded view of end effector  1  illustrated in  FIG. 1 . 
         FIG. 3  is a sectional view of rotary unit  12  illustrated in  FIG. 2 . 
         FIG. 4  is a view illustrating a step of peeling off release paper using end effector  1  (a first stage and a second stage). 
         FIG. 5  is a view illustrating a step of peeling off release paper using end effector  1  (a third stage and a fourth stage). 
         FIG. 6  is a view illustrating a step of peeling off release paper using end effector  1  (a fifth stage and a sixth stage). 
         FIG. 7  is a view illustrating three postures of rotary unit  12 , in which part (a) indicates a case where a first support is at start position S, part (b) indicates a case where the first support is at halfway position M, and part (c) indicates a case where the first support is at end position E. 
         FIG. 8  is a view illustrating a modification of a shape of guide groove  111  of end effector  1  according to an exemplary embodiment of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     Background to the Present Disclosure 
     A robot device used in a factory or the like can perform various operations by attaching an end effector to a robot arm. The work is, for example, picking components flowing on a factory production line or assembling components using a robot hand as an end effector. In general, the robot arm and the end effector are controlled by a control device (controller) connected to the robot arm. 
     As a type of end effectors, there are a type that includes fingers and grips a workpiece with the fingers, a type that can deform the distal end of a hand like a so-called soft hand, and the like. 
     When components are assembled in a factory, workpieces may be bonded to each other by an adhesive sheet such as a double-sided tape. This adhesive sheet is protected by release paper before the bonding step is performed. Accordingly, in order to perform the bonding step, the release paper needs to be peeled off from the adhesive sheet. 
     In the invention disclosed in PTL 1, the distal end portion of the claw portion needs to enter the boundary portion between the edge portion of the double-sided tape and the edge portion of the release paper corresponding thereto. In order for the robot device to automatically perform such an operation, it is necessary to accurately control the robot device. 
     Accordingly, in the present disclosure, the release paper is peeled off by a simpler method using an end effector including a needle. Such an end effector according to the present disclosure will be described below. 
     (Appearance Structure of End Effector  1 ) 
       FIG. 1  is a perspective view illustrating an appearance structure of end effector  1  according to one aspect of the present disclosure. Part (a) of  FIG. 1  illustrates a state in which cover  13  covers the tip of needle  121 , and part (b) of  FIG. 1  illustrates a state in which cover  13  is pivoted upward and the tip of the needle  121  is exposed. End effector  1  is connected to an articulated robot arm (not illustrated) to perform various operations on a workpiece. In this example, end effector  1  connectable to the robot arm performs work of peeling off the release paper from the adhesive sheet. 
     End effector  1  includes housing  11  and rotary unit  12 . End effector  1  may additionally include cover  13 . 
     Housing  11  is connected to the distal end of actuator A of the robot arm and substantially defines the outer shape of end effector  1 . Housing  11  includes guide groove  111 . Guide groove  111  is a groove that guides the movement of rotary unit  12  and has a dogleg shape in the illustrated example. However, the shape of the guide groove  111  is not limited to a dogleg shape. Guide groove  111  will be described in detail later. 
     Rotary unit  12  is disposed in housing  11 . Rotary unit  12  includes needle  121  at its distal end. Rotary unit  12  is driven by actuator A of the robot arm, pierces the release paper with needle  121 , rotates needle  121  together with rotary unit  12  to lift up the release paper in a scooping manner and peel off the release paper from the adhesive sheet. The mechanism of rotary unit  12  will also be described in detail later. 
     Cover  13  is a safety member that is provided at an end portion of housing  11  on the side opposite to actuator A and protects needle  121  of rotary unit  12  so as not to inadvertently pierce various places. In addition, cover  13  may also have a function of removing the release paper pierced by needle  121  from needle  121  as described later. Cover  13  will be described in detail later. 
     (Internal Structure of End Effector  1 ) 
       FIG. 2  is an exploded view of end effector  1  illustrated in  FIG. 1 .  FIG. 3  is a sectional view of rotary unit  12  illustrated in  FIG. 2 . The internal structure of end effector  1  will be described below with reference to  FIGS. 2 and 3 . Since a general actuator may be used as actuator A, a description of the actuator will be omitted. 
     In this example, rotary unit  12  may have a configuration like that illustrated on the right side of  FIG. 2 . First link plate  1201  is rotatably connected to one end of each of two second link plates  1202 A and  1202 B through first rotation shaft  1203 . Screw  1224  is inserted into first link plate  1201 , and screw  1224  is screwed into the distal end of actuator A (see  FIG. 3 ). 
     The other end of each of second link plates  1202 A and  1202 B is rotatably connected to holder  1204  through second rotation shaft  1205 . Holder  1204  has the shape formed by joining cylinder  1204 A and cylinder  1204 B orthogonal to each other. Second rotation shaft  1205  passes through cylinder  1204 A. Pipes  1206 A and  1206 B and ball bearings  1207 A and  1207 B are respectively provided at both ends of second rotation shaft  1205 . Second link plates  1202 A and  1202 B and ball bearings  1207 A and  1207 B are connected to second rotation shaft  1205  through pipes  1206 A and  1206 B. Ball bearings  1207 A and  1207 B constitute first support of rotary unit  12 . 
     Full screw  1209  is inserted into cylinder  1204 B of holder  1204 . As illustrated in  FIG. 3 , one end of full screw  1209  is fastened with nut  1213 , and the other end is fastened with nuts  1222  and  1223 . That is, full screw  1209  penetrates through each member between nut  1213  and nut  1223 . More specifically, full screw  1209  penetrates through nut  1213 , first hole  1212 A provided in rotation base  1212 , pipe  1208 , hole  1210 A provided in one end of U-shaped pin pressure plate  1210 , coil spring  1211  (elastic body), cylinder  1204 B, hole  1218 A provided in rotation base support  1218 , nut  1220 , pipe  1221 , hole  1210 B provided in the other end of pin pressure plate  1210 , nut  1222 , and nut  1223 . 
     Pipe  1208  is provided so as to cover a part of the outer periphery of full screw  1209 . One end of pipe  1208  is inserted and fastened in first hole  1212 A provided in rotation base  1212  (see  FIG. 3 ). The other end of pipe  1208  is inserted and fastened in hole  1218 A provided in rotation base support  1218  (see  FIG. 3 ). Pipe  1208  penetrates through hole  1210 A provided in one end of pin pressure plate  1210 , coil spring  1211 , and cylinder  1204 B. Coil spring  1211  is disposed to wind around the outside of pipe  1208 . Coil spring  1211  is disposed between one end of pin pressure plate  1210  closer to hole  1210 A and cylinder  1204 B, and exerts an elastic force between them. 
     Pipe  1221  is provided so as to cover a part of the outer periphery of full screw  1209 . Pipe  1221  passes through hole  1210 B provided in the other end of pin pressure plate  1210 , and one end of pipe  1221  is fastened with nut  1220  and the other end is fastened with nut  1222 . 
     Stepped pin  1214  is inserted into second hole  1212 B provided in rotation base  1212 . Stepped pin  1214  serves as needle  121  of rotary unit  12 . The rear end of stepped pin  1214  is reduced in diameter. The portion of stepped pin  1214  which is reduced in diameter is expressed as shoulder portion  1214 A. 
     One end of each of two pipes  1216 A and  1216 B is inserted into rotation base  1212 . The other end of each of two pipes  1216 A and  1216 B is inserted into a corresponding one of two holes  1218 C and  1218 D provided in rotation base support  1218 . Hexagon socket bolts  1219 A and  1219 B are respectively inserted into pipes  1216 A and  1216 B through holes  1218 C and  1218 D. 
     Pipe  1215  is provided between rotation base  1212  and rotation base support  1218 . Stepped pin  1214  described above is inserted into pipe  1215 . Shoulder portion  1214 A of stepped pin  1214  abuts on cylindrical receiving portion  1218 B provided on rotation base support  1218  (see  FIG. 3 ). 
     Small-diameter coil spring  1217  is disposed between rotation base support  1218  and an end of hole  1210 B of pin pressure plate  1210 . A diameter reduced portion of the rear end of stepped pin  1214  is inserted into coil spring  1217 . 
     For example, rotary unit  12  having the above structure is housed in housing  11  (see  FIG. 2 ). Guide grooves  111  are provided in both sides of housing  11 . In the illustrated example, ball bearings  1207 A and  1207 B are attached so as to cooperate with guide grooves  111 . 
     Housing  11  has holes  112 A and  112 B in its lower portion. There is a space between hole  112 A and hole  112 B. Small-diameter rod R passes through hole  112 A, cylinder  1212 C, and hole  112 B while cylinder  1212 C of rotary unit  12  is disposed in this space. Then, rotary unit  12  and housing  11  are rotatably connected to each other through small-diameter rod R. Cylinder  1212 C is the second support of rotary unit  12 . As is clear from  FIGS. 2 and 3 , cylinder  1212 C as the second support is provided on a side closer to the tip of needle  121  (stepped pin  1214 ) than ball bearings  1207 A and  1207 B as the first support. 
     Although not essential, cover  13  is attached to housing  11 . Holes  113 A and  113 B are provided in both sides of the lower portion of housing  11 . In a state where fulcrum portions  13 A and  13 B provided on both wings of cover  13  are aligned with holes  113 A and  113 B, rotation shaft  13 C passes through hole  113 A, fulcrum portion  13 A, fulcrum portion  13 B, and hole  113 B. With such a configuration, cover  13  is pivotable with respect to housing  11 . 
     (Step of Peeling Off Release Paper Using End Effector  1 ) 
       FIGS. 4 to 6  are views illustrating a process of peeling off the release paper using end effector  1 .  FIG. 4  illustrates a first stage and a second stage,  FIG. 5  illustrates a third stage and a fourth stage, and  FIG. 6  illustrates a fifth stage and a sixth stage. The step of peeling off the release paper will be described with reference to  FIGS. 2 and 3  described above as necessary in addition to  FIGS. 4 to 6 . Note that reference numerals may not be provided for constituent elements, of the constituent elements of end effector  1 , which are not directly related to the step of peeling off the release paper. 
     The first stage illustrated on the left side of  FIG. 4  illustrates the time of starting peeling off the release paper from adhesive sheet T using end effector  1 . In this example, it is assumed that adhesive sheet T is placed on a working floor surface (including the upper surface of a mounting table in a factory line). 
     At the time of starting peeling off, end effector  1  is in a state of floating from the floor surface. In addition, cover  13  is at a position to hide needle  121  to secure safety. Although ball bearings  1207 A and  1207 B constitute the first support of rotary unit  12  as described above, the first support is located at start position S of guide groove  111 . Note that the start position, end position, and intermediate position of illustrated guide groove  111  having a dogleg shape are denoted by S, E, and M, respectively. In this drawing, intermediate position M is a position where the angle of the groove changes. 
     Next, in the second stage illustrated on the right side of  FIG. 4 , the robot arm (not illustrated) moves, so that end effector  1  connected to the robot arm descends and comes into contact with the floor surface. Cover  13  pivots about rotation shaft  13 C inserted into fulcrum portions  13 A and  13 B (see  FIG. 2 ). Convex part  132  is provided on a lower portion of cover  13 . When end effector  1  descends, convex part  132  first comes into contact with the floor surface. Accordingly, when end effector  1  further descends, cover  13  pivots in the clockwise direction in  FIG. 4  so that the end of cover  13  which is located on the opposite side to fulcrum portions  13 A and  13 B rises. This pivoting exposes needle  121  hidden inside cover  13 . That is, cover  13  is removed from the tip of needle  121 . 
     Next, in the third stage illustrated on the left side of  FIG. 5 , actuator A pushes first link plate  1201  downward (see also  FIG. 3 ). Then, first rotation shaft  1203  and one end of each of second link plates  1202 A and  1202 B are pushed down. In this case, ball bearings  1207 A and  1207 B as the first support are fitted so as to be movable along guide groove  111 . Accordingly, the other end of each of second link plates  1202 A and  1202 B moves from start position S of guide groove  111  to intermediate position M along guide groove  111  together with ball bearings  1207 A and  1207 B constituting the first support. As can be seen from a comparison between the second stage and the third stage, second link plates  1202 A and  1202 B are swing links that swing in response to pressing by actuator A. 
     Reference is also made to  FIGS. 2 and 3 . When ball bearings  1207 A and  1207 B as the first support move from start position S to intermediate position M, coil spring  1211  pushed by cylinder  1204 B pushes one end ( 1210 A side) of pin pressure plate  1210 . In conjunction with this, the other end ( 1210 B side) of pin pressure plate  1210  then pushes stepped pin  1214 , and the tip of stepped pin  1214  protrudes. That is, needle  121  protrudes and lightly pierces the release paper on the surface of adhesive sheet T placed on the floor surface. With the above mechanism, coil spring  1211  has a function of adjusting the pressure applied to the release paper by needle  121 . Conversely, when it is not necessary to adjust the pressure applied to the release paper by needle  121 , coil spring  1211  is unnecessary. In this case, the configuration may be changed to a configuration in which needle  121  simply protrudes according to the movement of ball bearings  1207 A and  1207 B as the first support, for example, by placing a pipe having no elastic force instead of coil spring  1211 . Note that subtended angle α on the left side of  FIG. 5  will be described together with the fourth stage illustrated on the right side of  FIG. 5 . 
     Next, in the fourth stage illustrated on the right side of  FIG. 5 , actuator A further pushes first link plate  1201  downward (see also  FIG. 3 ). Then, first rotation shaft  1203  and one end of each of second link plates  1202 A and  1202 B are further pushed down. In this case, ball bearings  1207 A and  1207 B are fitted so as to be movable along guide groove  111 . Accordingly, the other end of each of second link plates  1202 A and  1202 B moves from intermediate position M of guide groove  111  to end position E along guide groove  111  together with ball bearings  1207 A and  1207 B constituting the first support. 
     It has already been described that ball bearings  1207 A and  1207 B constitute the first support of rotary unit  12  and that cylinder  1212 C is the second support of rotary unit  12 . Cylinder  1212 C (and hole  112 B) is in contact with the floor surface on which adhesive sheet T is placed in both the third stage and the fourth stage. That is, the position of the second support of rotary unit  12  does not substantially change even with transition from the third stage to the fourth stage. On the other hand, ball bearings  1207 A and  1207 B constituting the first support are pushed down along guide groove  111  from intermediate position M to end position E. As a result, the line segment connecting the first support and the second support falls down toward the floor surface. That is, subtended angle α between the line segment connecting the first support and the second support and the floor surface decreases with transition from the third stage to the fourth stage. As a result, rotary unit  12  itself falls down toward the floor surface with transition from the third stage to the fourth stage. Then, the angle of needle  121  with respect to the floor surface also gradually decreases. 
     As the angle of needle  121  with respect to the floor surface gradually decreases, needle  121  that has lightly pierced the release paper in the third stage lifts up a part of the release paper to peel off it from adhesive sheet T (the state on the right side of  FIG. 5 ). Release paper P being peeled off from adhesive sheet T is illustrated on the right side of  FIG. 5 . 
     Note that, in the state on the right side of  FIG. 5 , since the tip of needle  121  is not already grounded, a force for keeping coil spring  1211  (see  FIGS. 2 and 3 ) contracted does not work. In other words, the force for compressing coil spring  1211  is released. Accordingly, coil spring  1211  is in an extended state. Then, the tip of needle  121  further protrudes in conjunction with coil spring  1211 . 
     Next, in the fifth stage illustrated on the left side of  FIG. 6 , the robot arm to which end effector  1  is connected is operated to raise end effector  1  while release paper P is hooked on needle  121 . Entire release paper P is then peeled off from adhesive sheet T. 
     In the sixth stage illustrated on the right side of  FIG. 6 , cover  13  pivots counterclockwise in the drawing, the bottom surface of cover  13  comes into contact with the release paper, and release paper P pierced by needle  121  starts to be removed from needle  121 . 
     The process then returns to the first stage illustrated on the left side of  FIG. 4 . In the first stage, release paper P has already been removed. Since actuator A returns to the initial state, rotary unit  12  also returns to the initial state as illustrated on the left side of  FIG. 4 . 
     As described above, using end effector  1  according to an exemplary embodiment of the present disclosure makes it possible to easily peel off the release paper from the adhesive sheet. Since the release paper is pierced by needle  121  and peeled off by being scooped up, high accuracy is not required in the operation of the robot arm and end effector  1 . 
       FIG. 7  is a view illustrating three postures of rotary unit  12 , in which part (a) of  FIG. 7  indicates a case where the first support is at start position S, part (b) of  FIG. 7  indicates a case where the first support is at halfway position M, and part (c) of  FIG. 7  indicates a case where the first support is at end position E. Note that part (a) of  FIG. 7  corresponds to the second stage illustrated in  FIG. 4 , part (b) of  FIG. 7  corresponds to the third stage illustrated in  FIG. 5 , and part (c) of  FIG. 7  corresponds to the fourth stage illustrated in  FIG. 5 . Further, the illustration of cover  13  is omitted. 
     As described above,  FIG. 7  illustrates that the first support moves along guide groove  111  having a dogleg shape to cause needle  121  to protrude at intermediate position M and be inclined so as to lie sideways at end position E. 
     (Modification 1: Angle of Line Segment ME) 
       FIG. 8  is a view illustrating a modification of the shape of guide groove  111  of end effector  1  according to the exemplary embodiment of the present disclosure. As illustrated in part (a) of  FIG. 8 , guide groove  111  has start position S, intermediate position M, and end position E. A line segment connecting start position S and intermediate position M is defined as line segment SM. A line segment connecting intermediate position M and end position E is defined as line segment ME. The angle formed between line segment SM and the horizontal direction when end effector  1  is placed on the floor surface is θ 1 . The angle formed between line segment SM and line segment ME is θ 2 . At this time, in end effector  1  illustrated in  FIGS. 1 to 7 , start position S, intermediate position M, and end position E are determined so that line segment ME descends perpendicularly to the floor surface, that is, θ 2 =θ 1 +90°, and guide groove  111  is formed along line segment SM and line segment ME. This produces the following preferable effects. When the first support moves along line segment SM, needle  121  in rotation unit  12  protrudes, whereas when the first support moves along line segment ME, needle  121  tilts toward the floor surface to scoop up the release paper. 
     However, the angle of line segment ME is not limited to the above angle. For example, as illustrated in part (b) of  FIG. 8 , angles θ 1  and θ 2  are determined so as to satisfy θ 1 &lt;θ 2 &lt;θ 1 +180°, start position S, intermediate position M, and end position E are determined on the basis of these angles, and guide groove  111  can be formed along line segment SM and line segment ME. 
     (Modification 2: Curved Guide Groove) 
     In addition, in end effector  1  described above, the shape of guide groove  111  is formed along the locus obtained by joining the two straight lines of line segment SM and line segment ME. However, the shape of guide groove  111  can also be determined along the locus of the curve. 
     For example, consider a case where there is inflection point M′ on the curve as illustrated in part (c) of  FIG. 8 . The inflection point refers to a point on a continuous curve at which the curve changes from concave to convex or vice versa. Assuming that inflection point M′ is an intermediate position, straight line segment SM′ and line segment M′E are drawn on the basis of three points (start position S, inflection point M′, and end position E) included in the original curve, and angle θ 1  and angle θ 2  are determined in the same manner as described above on the basis of these two line segments. When angles θ 1  and θ 2  satisfy the inequality θ 1 &lt;θ 2 &lt;θ 1 +180°, the shape of guide groove  111  may be determined along the original curve. 
     In addition, as illustrated in part (d) of  FIG. 8 , when there is no inflection point on the curve, an arbitrary point on the curve may be determined as intermediate position N. Then, angles θ 1  and θ 2  are determined on the basis of line segment SN and line segment NE which are straight lines. When angles θ 1  and θ 2  satisfy the inequality θ 1 &lt;θ 2 &lt;θ 1 +180°, the shape of guide groove  111  may be determined along the original curve. 
     As described above, swing link  1202  that swings in response to pressing by actuator A may be further provided, and swing link  1202  may be connected to the first support (ball bearings  1207 A and  1207 B). As a result, the swing link receives the pressing force by actuator A and transmits the force to the first support. Accordingly, the first support appropriately moves along guide groove  111 . 
     In addition, rotary unit  12  may include coil spring  1211  (elastic body) for adjusting pressurization to release paper by needle  121 . Accordingly, the pressing force can be adjusted so that needle  121  does not pierce the release paper together with adhesive sheet T. 
     In addition, guide groove  111  may have a dogleg shape. This makes it possible to cause needle  121  to protrude and pierce the release paper and to scoop up the release paper, thereby peeling off the release paper from adhesive sheet T. 
     Assume that guide groove  111  has start position S, intermediate position M, and end position E, a line segment connecting start position S and intermediate position M is defined as line segment SM, a line segment connecting intermediate position M and end position E is defined as line segment ME, the angle formed between line segment SM and the horizontal direction when end effector  1  is placed on the floor surface is defined as θ 1 , and the angle formed between line segment SM and line segment ME is defined as θ 2 , θ 1 &lt;θ 2 &lt;θ 1 +180° is satisfied. More specifically, θ 1 +45°&lt;θ 2 &lt;θ 1 +135° is satisfied, and more specifically, θ 2 =θ 1 +90° is satisfied. As a result, the movement of rotary unit  12  and needle  121  of rotary unit  12  can be appropriately defined while first support moves from intermediate position M to end position E. 
     Rotary unit  12  may further include second support (cylinder  1212 C), and the second support may be provided on a side closer to the tip of needle  121  than the first support portion. As a result, the first support moves along guide groove  111  with the second support provided on the side close to the tip of needle  121  as a fulcrum, so that rotary unit  12  rotates to peel off the release paper by scooping up it with needle  121 . 
     Further, cover  13  for protecting needle  121  is further provided, and cover  13  pivots with respect to housing  11  to remove the peeled release paper. As a result, cover  13  can have a function of removing peeled release paper in addition to the safety function. 
     While various exemplary embodiments have been described in the foregoing with reference to the drawings, it is obvious that the present disclosure is not limited thereto. For those skilled in the art, it is obvious that various modification examples, rectification examples, substitution examples, addition examples, deletion examples, and equivalent examples could be conceived within the scope of claims, and thus it is obviously understood that those examples belong to the technical scope of the present disclosure. Additionally, each component in the various exemplary embodiments described above may be appropriately combined without departing from the spirit of the disclosure. 
     The present disclosure is useful as an end effector that can peel off release paper.