JP2005153123A - Gripper and work carrying device using the gripper - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a gripper of a two finger-gripping type capable of gripping works with different diameters without exchanging a finger, without causing a fluctuation in the center of the work, and maximizing a maximum opening degree of fingers. <P>SOLUTION: A pair of right and left fingers 25 are moved along a substantially L-shaped groove cam 24 of a cam plate 22 by the operation of an actuator unit 16 through a link 32 to make opening and closing operation. While the fingers 25 are opened and closed based on a parallel movement between a close position P1 and an intermediate position P3, the fingers 25 are opened and closed based on a rotational movement between the intermediate position P3 and a maximum open position P2. Therefore, even when gripping a work W with different diameters, the center of the work W is not fluctuated. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a gripper device of a so-called two-finger grip type for gripping a workpiece and a transfer type transport device using the gripper device, and more particularly to flexibly gripping workpieces of different diameters when gripping a cylindrical workpiece. The present invention relates to a gripper device and a workpiece transfer device that can cope with each other, and even if the diameter of a workpiece to be gripped changes, the center position thereof does not change.

As a typical example of this type of two-finger gripping device, as described in Patent Document 1, for example, a pair of fingers rotate in a direction approaching and separating from each other about a single or independent hinge pin as a rotation center. There are known ones that allow the opening and closing operation to be performed, and as described in Patent Document 2, a pair of fingers that are moved in close proximity to each other while being in a parallel state to perform the opening and closing operation. ing.
Japanese Patent No. 3365276 JP 2000-343474 A

  In the former gripper device, when trying to grip a cylindrical workpiece having a different diameter with a common finger, the center position of the workpiece in the gripped state is shifted each time based on the difference in diameter. Therefore, if it is desired to match the center position regardless of the workpiece diameter, it is necessary to replace the finger each time depending on the workpiece diameter difference, and the gripper operation rate decreases due to the occurrence of setup change. That is not preferable.

  On the other hand, in the latter gripper device, since the pair of fingers move in a so-called parallel manner, the center position does not shift even when gripping a cylindrical workpiece of different diameters, but the former type Unlike the finger opening, it is not possible to ensure a large opening. For this reason, for example, when used as a work gripper of a transfer type transport device mainly composed of a reciprocating transfer bar, it is necessary to move the gripper forward and backward each time the work is gripped and released, and the cycle time required for transport is reduced. Not only is it long, but there is a limit to speeding up workpiece transfer.

  The present invention has been made paying attention to such problems, and can overcome the disadvantages of the conventional two-finger gripping device, and can handle the grip of a workpiece with a particularly different diameter. In addition, it is an object of the present invention to provide a gripper device and a workpiece transfer device that can increase the speed of transfer.

  The invention according to claim 1 is a two-finger gripping type in which a workpiece is gripped by a pair of fingers that are opened and closed synchronously rotating in directions approaching and separating from each other with mutually independent parallel pins as rotation centers. It is assumed that it is a gripper device.

  In addition, each finger is displaceable between an opening / closing stroke formed by a closed position where the workpiece is gripped and a maximum opened position after the workpiece is released, and from the intermediate position of the opening / closing stroke. Each finger performs an opening / closing operation based on a rotational motion until the maximum open position, while each finger moves in a parallel manner between the intermediate position of the opening / closing stroke and the closing position so that the fingers open / close. The movement trajectory of the finger is set.

  The gripper device described above can be used as a mechanical hand or a chuck of various automated machines or transfer machines as well as a hand of an industrial robot, for example. Thus, it can also be used as a workpiece gripping part of a so-called transfer type conveying apparatus.

  In addition, in the state in which each finger is in the maximum open position, as described in claim 2, it is desirable that the opening degree of both the fingers is set to be an obtuse angle.

  Here, in order to cause each finger to perform the opening / closing operation based on the rotational motion and the opening / closing operation based on the parallel movement as described above, each finger is provided independently as described in claim 3. For the substantially L-shaped groove cam in which the straight line portion is made to coincide with the opening / closing operation direction based on the parallel movement, the finger can be rotated via a pair of pins and along the one straight line portion. The guide is supported so as to be slidable, and the finger is moved forward and backward along one linear portion of the groove cam.

  More specifically, as described in claim 4, the cam plate can be rotated via a cam plate in which a groove cam is formed, and two cam followers engaged with the groove cam with respect to the cam plate. It is assumed that there are provided fingers that are guided and supported so as to be slidable along the one linear portion, and drive means for moving the fingers forward and backward along the one linear portion of the groove cam.

  The drive means in this case is provided with a single direct acting actuator that is shared by both fingers and moves forward and backward in the direction of approaching and separating from each other as described in claim 5. And

  More specifically, as described in claim 6, the driving means includes a pair of sliders that move close to and away from each other in the same direction as the opening / closing operation direction based on the parallel movement of the fingers by the operation of the linear actuator. It is assumed that each slider and a link connecting each finger are provided.

  The invention according to claim 7 is specified as a workpiece transfer device using the gripper described above, and is capable of reciprocating in the longitudinal direction across a plurality of stages set at equal pitches and linearly. The transfer bar is equipped with a plurality of grippers at the same pitch as the inter-stage pitch, and the transfer bar moves forward after the workpiece on each stage is held by each gripper. Based on the above, it is assumed that the transfer type work transfer device is configured to transfer to the next stage all at once. In addition, the gripper according to any one of claims 1 to 6 is mounted on the transfer bar as a gripper.

  Therefore, according to the first and seventh aspects of the present invention, each finger performs an opening / closing operation based on the rotational movement between the middle position of the opening / closing stroke and the maximum opening position, and between the middle position of the opening / closing stroke and the closing position. Then, since each finger moves in parallel with each other and opens and closes, the center position of the workpiece in the gripping state does not change at all even if the diameter of the workpiece to be gripped changes.

  On the other hand, even if the fingers release the workpiece, as long as the fingers are in a parallel state, for example, even if an attempt is made to retract the entire gripper in the approaching / separating direction between the fingers based on the parallel movement, interference with the workpiece after the release is caused. Therefore, it cannot be evacuated. Therefore, between the intermediate position of the open / close stroke and the maximum open position as described above, each finger performs an open / close operation based on rotational movement, so that the gripper as a whole moves in the direction of approaching and separating the fingers based on parallel movement as described above. When retreating, the gripper can be retreated in the same direction while avoiding the interference with the released work without difficulty.

  According to the first aspect of the present invention, since the fingers move in parallel with each other between the intermediate position of the opening / closing stroke and the closing position, the fingers move in the opening / closing operation. The position does not fluctuate, and it is possible to flexibly cope with the conveyance of various kinds of workpieces, and the versatility as a gripper is enhanced, and the setup change operation can be eliminated.

  In addition, each finger performs an opening and closing operation based on rotational movement between the middle position of the opening and closing stroke and the maximum opening position, so if the fingers rotate to the maximum opening position, they will not interfere with the released workpiece. For example, there is an advantage that the entire gripper can be immediately retracted in the approaching / separating direction of the fingers based on parallel movement, and the high-speed conveyance can be flexibly handled.

  According to the seventh aspect of the present invention, as the gripper attached to the transfer bar of the transfer type conveying device, the gripper that can perform the opening / closing operation based on the rotational motion and the opening / closing operation based on the parallel movement as described above is used. If the fingers rotate to the maximum open position, the gripper will not interfere with the released workpiece, and the entire gripper can be immediately retracted in the approaching / separating direction between the fingers based on parallel movement, for example. High speed can be achieved.

  1 to 4 are views showing a preferred embodiment of a transfer type work conveying apparatus using a two-finger gripping gripper apparatus according to the present invention. 1 is a plan view of the main part, FIG. 2 is a front view of FIG. 1, and FIG. 3 is a left side view of FIG. FIG. 4 shows the structure of a transfer drive mechanism installed at a portion connected to the left end of FIG. In this embodiment, as shown in FIGS. 5 and 8, for example, a case where a small-diameter shaft portion C1 of a so-called stepped shaft-shaped workpiece W having a small-diameter shaft portion C1 and a large-diameter portion C2 is gripped is shown. .

  As shown in FIGS. 1 to 3, a plurality of stages S1, S2,... Sn for various processing, processing or work are set on the gantry 1 in a straight line and at an equal pitch. A pair of left and right transfer bars 2, 2 that can reciprocate across the stages S1, S2,... Sn are arranged in parallel to each other. A guide bar 3 having a predetermined length is provided on the gantry 1 at regular intervals via a bracket 4, and the transfer bars 2 and 2 are slid onto the guide bar 3 via a slide unit 5. Guided support is possible.

  A two-finger gripping gripper 6 is mounted at a position corresponding to each of the stages S1, S2,... Sn of the transfer bars 2 and 2 via a mounting plate 7 connecting the transfer bars 2 and 2 to each other. ing. Since the interstage pitch P (see FIG. 2) is set so as to fall within the length of the guide bar 3, the transfer bars 2 and 2 are linearly reciprocated using the interstage pitch P as a stroke. Thus, the grippers 6, 6... Also reciprocate under the same stroke so that the workpieces W of the respective stages S1, S2... Sn are gripped and conveyed to the next stage all at once. It has become.

  Here, as shown in FIG. 4, a motor 8 capable of forward / reverse rotation is provided at the end of the gantry 1 as a transfer drive mechanism, and the drive wheels 9 that are driven to rotate by the motor 8 and the gantry 1 side. A winding transmission element 11 such as a toothed belt or a chain is wound around the driven wheel 10. Further, a turning arm 12 is provided coaxially with the driven wheel 10, and this turning arm 12 is driven forward and backward with a rotation angle of 180 degrees, for example. On the other hand, the pair of transfer bars 2 and 2 are provided with a connecting bracket 13 that extends downward while connecting the two to each other, and the connecting bracket 13 and the swivel arm 12 are connected to each other via a connecting rod 14. Yes. Therefore, as described above, the swivel arm 12 is driven forward / reversely with a rotation angle of 180 degrees, so that a pair of left and right transfer bars 2 and 2 and a plurality of grippers 6 attached to the transfer bars 2 and 2 are provided. 6 ... reciprocate all at once along the guide bar 3 with the pitch P between the stages as a stroke.

  5 to 7 show details of a so-called two-finger gripper 6 attached to the above-described transfer bars 2 and 2, and as is apparent from FIG. 7, each gripper 6 has a pair of transfer bars 2 and 2. Are mounted on the mounting plate 7 connecting the two via an angle-shaped bracket 15.

  Each gripper 6 is configured symmetrically about a linear-acting actuator unit 16 having a substantially prismatic shape fixed on a mounting plate 7, and the casing 17 is disposed on both sides of a casing 17 of the actuator unit 16. A pair of rectangular block-shaped sliders 18 are arranged to face each other. These sliders 18 are guided and supported by the casing 17 through a pair of guide bars 19 and 20 so as to be able to approach and separate from each other. A rack integral with one guide bar 19 and a pinion that meshes with this rack are built in, and the built-in air cylinder extends to move the left and right sliders 18 in parallel to move in parallel, that is, move toward and away from each other. It is like that.

  Further, two upper and lower cam plates 22 having a substantially rectangular shape are mounted on the mounting plate 7 via a holder block 21 so as to overlap each other. These cam plates 22 are provided with a spacer 23 between them so that a gap corresponding to the height of the spacer 23 is secured, and each cam plate 22 has a substantially L-shape in plan view. A pair of left and right groove cams 24 are formed symmetrically. As apparent from FIG. 5, these groove cams 24 are formed in a substantially L shape by smoothly connecting a pair of long and short straight portions 24a and 24b having an arcuate corner portion. The straight line portion 24a is made to coincide with the approaching / separating direction of the sliders 18, 18. A base portion 25a of a pair of left and right fingers 25 that is also substantially L-shaped and opens and closes in synchronization with each other is mounted in the gap formed by the cam plates 22 and 22 described above.

  As is apparent from FIG. 5, these fingers 25 are movable between an opening / closing stroke formed by a closed position P1 for gripping the workpiece W and a maximum open position P2 after the workpiece W is released. In the middle of the opening / closing stroke, between the intermediate position P3 and the closed position P2, both fingers 25, 25 remain in a parallel state so as to perform a so-called parallel movement and open / close operation. Each finger 25 is set to perform an opening / closing operation based on a rotational motion between P3 and the maximum open position P2. Note that the angle formed by the fingers 25 and 25 at the maximum open position P2 is set to be an obtuse angle.

  That is, a detachable claw portion 56 is attached to the tip of each finger 25, and the base 25a of the finger 25 is paired up and down via a pin 26 or a hinge pin 27 that penetrates the base 25a itself. Two sets of the cam follower roller 28 and the drive side cam follower roller 29 are provided in the horizontal direction while maintaining a predetermined distance between the shafts. The driven cam follower roller 28 and the drive side cam follower roller 29 move relative to the upper and lower groove cams 24. Engagement possible. As is apparent from FIG. 5, it is considered that the driven cam follower roller 28 and the drive cam follower roller 29 that are adjacent to the shorter straight portion 24 b of the groove cam 24 in the horizontal direction are not located at the same time. The finger 25 is set to the maximum open position P2 when the driven cam follower roller 28 is positioned at the stroke end of the shorter straight portion 24b of the groove cam 24, while the groove cam 24 It is considered that the driven cam follower roller 28 and the driving cam follower roller 29 adjacent to each other in the horizontal direction can be simultaneously positioned in the longer straight portion 24a. As described above, the driven cam follower roller 28 and the drive cam follower roller 29 that are adjacent to the common linear portion 24a in the horizontal direction are positioned at the same time, so that the fingers 25 and 25 are parallel to each other in this state. Is set.

  In other words, each finger 25 performs an opening / closing operation based on the rotational movement between the intermediate position P3 of the opening / closing stroke and the maximum opening position P2, while each finger 25 performs an opening / closing operation based on the rotational movement. The movement trajectory of each finger 25 is set so that the fingers 25 and 25 move in parallel with each other and open and close.

  On the other hand, a pair of left and right sliders 18 are connected with extension blocks 30 having a substantially L shape in a plan view as shown in FIG. 5 by bolts 31 so as to be parallel to each other. The block 30 and the hinge pin 27 supporting the pair of upper and lower drive side cam follower rollers 29 are also connected to each other via a pair of upper and lower parallel links 32. Specifically, as shown in FIG. 7, one end of a link 32 is connected to the top and bottom of the hinge pin 27 via a collar 33, a washer 34, and a bolt 35 so as to be relatively rotatable. As shown in FIG. 6, the other end of the link 32 is connected to the upper and lower ends of the tip 30 via a hinge pin 36, a washer 37, and a bolt 38 penetrating therethrough so as to be relatively rotatable. When the left and right sliders 18, 18 are moved toward and away from each other based on the operation of the actuator unit 16, the left and right links 32 connected to the slider 18 via the extension block 30 are also moved closer to and away from each other in the longitudinal direction. As a result, the pair of left and right fingers 25, 25 connected to the link 32 are similarly moved toward and away from each other along the groove cam 24 using one hinge pin 27 as an input portion.

  In this way, a drive unit for opening and closing the pair of left and right fingers 25 while moving forward and backward is formed by the linear motion type actuator unit 16 and the pair of left and right sliders 18, the extension block 30 and the link 32.

  Therefore, according to the gripper 6 configured as described above, the pair of left and right sliders 18 and 18 are most separated from each other on the basis of the operation of the actuator unit 16, as indicated by a virtual line in FIG. 5 and a solid line in FIG. In this state, each finger 25 connected to the slider 18 via the extension block 30 and a pair of upper and lower links 32 is also short of the groove cam 24 along with the driven cam follower 28 and the driving cam follower roller 29. It has moved to the linear part 24b side. The drive side cam follower roller 29 is positioned at the longer straight portion 24a of the groove cam 24, while the driven side cam follower roller 28 is positioned at the stroke end of the shorter straight portion 24b of the groove cam 24. Therefore, in this state, each finger 25 is in an oblique state, but is in the maximum open position P2 and maintains the open state as the gripper 6.

  On the other hand, as shown by the solid lines in FIGS. 5 and 9, when the pair of left and right sliders 18 and 18 starts approaching from the maximum separated position toward the minimum separated position based on the operation of the actuator unit 16, Although the roller 29 moves linearly along the longer straight portion 24a of the groove cam 24, the driven cam follower roller 28 passes through the corner portion after passing through the shorter straight portion 24b of the groove cam 24. In this process, each finger 25 rotationally moves in accordance with the curvature of the corner of the groove cam 24 and gradually rises from the previous inclined state. 25, the driven cam follower roller 28 and the drive side cam follower roller 29 attached to 25 are both linear portions of the longer one of the groove cams 24. First both the fingers 25 and 25 to each other are parallel state at time or intermediate position P3 adapted to position in 4a.

  If the sliders 18 and 18 continue to approach each other, the driven cam follower roller 28 and the drive side cam follower roller 29 are both restrained by the longer linear portion 24a of the groove cam 24. As shown in the drawing, the 25 moves close to each other while maintaining a parallel state, and finally becomes a closed state (closed position P1) to grip the small diameter portion C1 of the workpiece W. As long as a predetermined fluid pressure is applied to the actuator unit 16, the gripping state of the workpiece W as shown in FIG.

  Further, when releasing the workpiece W gripped by the fingers 25, the actuator unit 16 is reversely operated to move the sliders 18 and 18 apart from each other. The workpiece W is released by opening operation under the completely opposite behavior.

  That is, the fingers 25 and 25 start to move with each other as the sliders 18 and 18 are separated from each other, and the fingers W and 25 are moved away from each other while being in a parallel state up to the intermediate position P3. To release. Then, after the intermediate position P3, the fingers 25, 25 gradually rotate along the cam groove 24 toward the maximum open position P2, and gradually increase the opening thereof. Finally, in FIG. In the state shown by the solid line in FIG. 8, the vehicle stops at its maximum open position P2.

  As described above, the gripper 6 according to the present embodiment always has both fingers 25, 25 between the intermediate position P3 and the closed position P1 regardless of whether it is during a workpiece gripping operation or a workpiece release operation. Will translate. Therefore, even if the diameter of the small-diameter portion C1 of the workpiece W to be gripped changes, not only does the center of the workpiece at the position where the workpiece is gripped or released not change, but also the difference in diameter is the above-described intermediate position P3 and the closed position. Scratching within the range of the stroke made with P1 can be handled without difficulty for gripping a workpiece having a different diameter without the need for changeover.

  Here, in the transfer type work conveying apparatus employing the gripper 6 described above, the distance between the adjacent grippers 6 and 6 is set to be the same as the inter-stage pitch P as shown in FIGS. By connecting the opening / closing operation of each gripper 6 to the reciprocating movement of the transfer bars 2 and 2, the work W of each stage S1, S2... Sn can be transferred to the next stage all at once. Stated.

  In this case, as shown in FIGS. 1 and 5, a distance D is secured in advance between the center of the workpiece W at the position where the workpiece W should be gripped or released and the tip of the finger 25 at the maximum open position P2. Therefore, for example, the workpiece W gripped by the stage S3 is transferred to the next stage S4 by the forward movement of the transfer bars 2 and 2, and when the workpiece W is released by the stage S4, the gripper 6 is immediately opened. The original stage S3 can be returned. That is, in the released state of the workpiece W, a distance D is secured between the center of the workpiece W and the tips of the fingers 25 and 25 in the open state, and the gripper 6 is moved back together with the transfer bars 2 and 2 as it is. Since they are set so that they do not interfere with each other even if operated, the forward and backward movement of the gripper 6 in the direction orthogonal to the reciprocating direction of the transfer bars 2 and 2 and the movement of the transfer bars 2 and 2 in the same direction Is completely unnecessary. As a result, the work transport cycle time can be shortened, and the work can be transported at high speed between a large number of stages.

The principal part top view which shows preferable embodiment of the workpiece conveyance apparatus which concerns on this invention. The front view of FIG. The left view of FIG. FIG. 3 is a schematic explanatory diagram of a transfer drive mechanism connected to the left end of FIG. 2. The enlarged plan view of the gripper in FIG. Front explanatory drawing of FIG. The left view of FIG. The top view in the workpiece | work release state of the gripper shown in FIG. FIG. 6 is a plan view of the gripper shown in FIG.

Explanation of symbols

2 ... Transfer bar 6 ... Gripper 16 ... Actuator unit (drive means)
18 ... Slider (drive means)
DESCRIPTION OF SYMBOLS 22 ... Cam plate 24 ... Groove cam 24a, 24b ... Linear part 25 ... Finger 26 ... Pin 27 ... Hinge pin 28 ... Drive side cam follower roller 29 ... Drive side cam follower roller 32 ... Link (drive means)
P1 ... Closed position P2 ... Maximum open position P3 ... Intermediate position S1, S2 ... Sn ... Stage W ... Workpiece

Claims (7)

A gripper device of a two-finger gripping type that grips a workpiece with a pair of fingers that rotate synchronously in a direction that approaches and separates from each other around mutually independent parallel pins,
Each finger is displaceable between the opening and closing strokes between the closed position where the workpiece is gripped and the maximum open position after the workpiece is released,
Each finger performs an opening / closing operation based on rotational movement between the middle position of the opening / closing stroke and the maximum opening position, while each finger moves in parallel with each other between the middle position of the opening / closing stroke and the closing position. A gripper device characterized in that the movement trajectory of each finger is set so as to operate.   The gripper device according to claim 1, wherein in a state where each finger is in a maximum open position, an opening degree formed by both of the fingers is set to be an obtuse angle. Fingers can be rotated via a pair of pins against a substantially L-shaped groove cam that is provided independently for each finger and has one straight line portion aligned with the opening / closing operation direction based on the above translation. In addition, the guide is supported so as to be slidable along the one linear portion.
The fingers are moved back and forth along one straight line portion of the groove cam to cause each finger to perform an opening / closing operation based on a rotational motion and an opening / closing operation based on a parallel movement. Item 3. The gripper device according to Item 1 or 2. A cam plate in which the groove cam is formed;
Fingers supported and supported by the cam plate so as to be rotatable through a pair of cam followers engaged with the groove cam and slidably movable along the one linear portion;
Driving means for moving the finger forward and backward along one linear portion of the groove cam;
The gripper device according to claim 3, further comprising:   5. The gripper according to claim 4, wherein the driving means includes a single linear actuator that is shared by both fingers and moves the fingers forward and backward in a direction to approach and separate from each other. apparatus. The drive means includes a pair of sliders that move closer to and away from each other in the same direction as the opening / closing operation direction based on the parallel movement of the fingers by the operation of the linear actuator.
A link connecting each slider and each finger;
The gripper device according to claim 5, further comprising: A transfer bar that can move back and forth in the longitudinal direction across multiple stages set at equal pitches and straight lines is arranged, and a plurality of grippers are mounted on this transfer bar at the same pitch as the above-mentioned inter-stage pitch. In the transfer type work transfer device that is configured to transfer to the next stage all at once based on the forward movement of the transfer bar after holding the work in each stage with each gripper,
A work conveying apparatus, wherein the gripper according to claim 1 is mounted on a transfer bar as a gripper.

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