Abstract:
A chuck device having a pair of arms rotatably supported by arm shafts and an operation member. One of the arms is provided with a roller shaft rotatable together with the arm about one of the arm shafts. The other arm is provided with an arm drive portion rotatable together with the arm. The arm drive portion is biased so as to press a second roller. Between the operation member and the roller shaft is provided a motion input mechanism for converting the motion of the operation member to rotational motion of the roller shaft about the arm shaft as the center of rotation. Between the roller shaft and the arm drive portion is provided an interlock mechanism that causes the arm drive portion to rotate about the arm shaft in conjunction with the motion of the roller shaft about the arm shaft as the center of rotation.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     The present invention relates to a chuck device for containers, a conveyor device equipped with the chuck device, and a chuck claw thereof.  
         [0002]     An example of a conveyor device used with a beer bottle inspection device or the like is a rotating star wheel device in which a disc referred to as a star wheel is formed with multiple pockets into which bottles are fit. By supporting and releasing bottles from the pockets, bottles can be placed in appropriate positions along the rotation path of the star wheel. Examples of bottle supporting structures of the star wheel device include one that uses a suction cup (e.g., Japanese laid-open patent publication number Hei 11-106039) and one that uses a pair of chuck claws that can open and close (e.g., Japanese laid-open patent publication number Hei 10-7243).  
         [0003]     Chuck-type star wheel devices are believed to be better suited for high-speed operations than suction-types, but designing a mechanical chuck device requires simple mechanisms and flexibility in operations. Also, when multiple chuck devices are to be provided, it must be possible to quickly attach and remove chuck claws to the chuck devices or else the maintenance for the chuck claws becomes too complex.  
       SUMMARY OF THE INVENTION  
       [0004]     The present invention provides a chuck device and a conveyor device using the chuck device that can improve the degree of freedom involved in operation, that can provide a simplified structure, and that can be suitable for higher conveyor speeds. The present invention also provides a chuck device with a removable chuck claw, a chuck claw used by the device, and a conveyor device that uses the chuck claw and the chuck device.  
         [0005]     According to the present invention a chuck device includes: supporting structure; a pair of arms rotatably supported on the supporting structure by way of a pair of arm shafts, chuck claws for grasping a container disposed on ends of the pair of arms that open and close in tandem with rotation around the arm shafts; and an operation member capable of being operated on externally. Inward from the pair of arms is disposed a first drive section capable of integrally rotating around the arm shaft of a first arm and being integral with the first arm, and a second drive section disposed further toward the end of the arm than the first drive section and capable of rotating integrally around the arm shaft of a second arm and being integral with the second arm. Biasing means biases the pair of arms around the arm shafts in a direction of closing the ends of the arms. A motion input mechanism is disposed between the operation member and the first drive section and converts external motion accompanying operation of the operation member to a rotation motion of the first drive section centered around the arm shaft. A coupling mechanism is disposed between the first drive section and the second drive section and converts rotational motion of the drive section around the arm shaft to a rotational motion of the second drive section around the arm shaft.  
         [0006]     With this chuck device, when the operation member is operated and the first drive section is rotated around the arm shaft, the second drive section also rotates around the arm shaft so that the pair of arms pivot to open and close the chuck claws. Since the motion of the operation member is first transmitted from the first drive section to the arm thereof, and this rotation motion is transmitted to the second drive section by way of a coupling mechanism, it is possible to define the operations of each arm by changing the way the motions are converted. For example, it is possible to change how the second arm moves without changing how the first arm moves in response to operation of the operation member, or the operation of the first arm in response to operation of the operation member can be changed while adjusting the coupling mechanism to cancel out this change so that the operation of the second arm does not change. Of course, the pair of arms can be operated symmetrically as well.  
         [0007]     In the first chuck device of the present invention, the motion input mechanism uses a cam mechanism to convert a motion of the operation member to rotation motion of the first drive section. By using the cam mechanism, the element opposing the cam surface (the cam driven element) can simply be pressed against it, eliminating the need for connecting the elements, e.g., with a linking mechanism. Thus, the structure is simplified and assembly and disassembly can be performed easily.  
         [0008]     According to another aspect, the cam mechanism of the motion input mechanism is equipped with an arm drive cam supported by the supporting structure to allow rotation around a cam axis line parallel to the arm shaft, a cam surface being formed on an outer perimeter of the arm drive cam. The arm drive cam is disposed opposite from the second drive section relative to the first drive section. The arm drive cam is rotated by external operation of the operation member. As the arm drive cam rotates, the cam surface of the arm drive cam moves back and forth between a position where the first drive section is pushed out toward the second drive section and a position where the first drive section is retracted to an opposite side from the second drive section.  
         [0009]     In this case, the arm drive cam rotates back and forth according to the direction in which the operation member is operated, and the first drive section is driven in the direction toward the second drive section or away from the second drive section. Since the second drive section is pushed against the first drive section by biasing means, the second drive section rotates around the arm shaft in tandem with the first drive section regardless of which direction the first drive section is driven.  
         [0010]     It is also possible for a first roller that comes into contact with the cam surface of the arm drive cam to be disposed on the first drive section. Using the roller can reduce the friction resistance at the cam surface, just making the mechanism operate more smoothly. Furthermore, a roller shaft parallel to the arm shaft can be disposed on the first drive section. On the roller shaft, there can be disposed a first roller coming into contact with the cam surface of the arm drive cam, and a second roller coming into contact with the second drive section.  
         [0011]     A support section can be disposed on the cam surface of the arm drive cam to support the first drive section at a position pushed out toward the second drive section. By providing this type of support section, when the first drive section is pushed out toward the second drive section by the biasing mechanism, the supporting force opposing the biasing mechanism force does not need to be applied continuously to maintain the arm drive cam at the same position. Thus, restrictions on the design of the mechanism for operating the operation member can be relaxed. For example, when the biasing mechanism biases the chuck claws in the closing direction, the absence of a supporting section would require keeping the chuck claws open by continuously guiding the operation member with a cam groove or the like so that the supporting force continues to be applied to the operation member. However, if the support section is provided, the first drive section can be guided to the support section to keep the arm drive cam and the first drive section at a fixed position without applying any force to the operation, thus allowing the chuck claws to be kept open. Thus, the mechanism for operating the operation member is simplified. Providing a cam groove or the like along the conveyor path to support the operation member leads to a larger cam and increases costs. In particular, if a cam groove is used, complex cleaning tasks are required to prevent clogging of the groove. Providing a support section on the cam surface eliminates this problem.  
         [0012]     The coupling mechanism can use a cam mechanism to convert rotation motion of the first drive section to rotation motion of the second drive section. In this case, the use of the cam mechanism eliminates the need to connect the first drive section and the second drive section together. Thus, the structure is simplified and assembly and disassembly is made easy. In particular, it is preferable to have both the motion input mechanism and the coupling mechanism use cam mechanisms. In one preferable form of the cam mechanism of the coupling mechanism, a cam surface that comes into contact with the first drive section is disposed on the second drive section. By changing the shape of the cam surface, the manner in which the second arm works in response to the first arm can be changed.  
         [0013]     The biasing mechanism can include one or more springs disposed between the support means and the second arm and biasing the second arm so that the chuck claws are biased in a closing direction. Simply providing biasing means between the arms will not restrict the arms to turn in the same direction around the arm shafts. When this type of motion takes place, the first drive section and the second drive section are displaced away from each other, and the coupling of the arms is temporarily lost, allowing the arms to move freely. However, in the above structure where the biasing mechanism is extended between the support structure and the second arm, the second drive section can be pressed toward the first drive section regardless of how the arms are operating.  
         [0014]     The biasing means can be torsion coil springs on each of the pair of arm shafts to bias the pair of arms so that the ends are biased in a closing direction. By providing torsion coil springs on the arm shaft, the pair of arms can be biased symmetrically, and the need to extend the arms back past the arm shaft is eliminated. As a result, the structure of the arms is simplified, and the space behind the arms can be used effectively.  
         [0015]     Furthermore, in the structure in which the arm drive cam is disposed on the cam mechanism as described above, it is possible to have torsion coil springs disposed as biasing means on each of the pair of arm shafts to bias the pair of arms so that the ends are biased in a closing direction; and both ends of a cam shaft can rotatably support the pair of arm shafts and the arm drive cam can be supported by the supporting structure. As a result, the arm shaft and the cam shaft of the arm drive cam can be firmly supported so that these elements are prevented from flexing.  
         [0016]     The first conveyor device according to the present invention includes: the first chuck device according to the present invention; and a mobile body moving the support structure of the chuck device along a predetermined conveyor path. With this type of conveyor device, containers can be conveyed by supporting the container with the chuck device while the mobile body moves. Multiple chuck devices can be disposed along the conveyor path of the mobile body. For example, in a star wheel conveyor device, chuck devices can be disposed along the outer perimeter of a rotating wheel and oriented outward, i.e., with the chuck claws oriented toward the outer perimeter side. Furthermore, an operation section can be provided on the conveyor path that operates an operation member by coming into contact with the operation member in response to movement of the chuck device. By operating the operation member using the operation section, the chuck claws can be closed or opened at a predetermined position on the conveyor path, so that a container can be retrieved or deposited.  
         [0017]     The operation section can include a movable section capable of moving between an active position, where the operation section is in contact with the operation member and operates the operation member, and a stand-by position away from the operation member. In this case, by switching the active unit between an active position and a stand-by position, it is possible to change whether or not the chuck claws operate at the positions where the active units are installed. Furthermore, the movable section can be driven by an electrical servo motor between the active position and the stand-by position. By using a servo motor, accurate operations can be performed at high-speeds. Thus, the invention can handle high-speed conveyors better.  
         [0018]     A second chuck device according to the present invention provides a chuck device wherein a chuck claw is removably mounted on an end of an arm driven to perform a grasping action. A cylindrically indented bearing surface is disposed on the arm. A holding piece equipped with a cylindrical outer perimeter surface curved along the bearing surface is disposed on the bearing surface using tightening mechanism. An attachment base curved along the bearing surface and capable of being inserted between the support piece and the bearing surface is disposed on the chuck claw.  
         [0019]     With this chuck device, the tightening applied by the tightening mechanism on the support piece can be loosened to enlarge the gap between the bearing surface and the support piece, the attachment base of the chuck claw can be inserted into the gap, and the support piece can be tightened against the bearing surface to have the support piece and the bearing surface support the interposed chuck claw. Since the bearing surface and the support piece have cylindrical surfaces, the chuck claw is prevented from rotating by the bearing surface and the support piece. As a result, further operations to prevent rotation of the support piece and the chuck claw are not needed. For example, even if a single bolt is used as the tightening mechanism, the chuck claw will not rotate around the bolt. Thus, according to the second chuck device of the present invention, the chuck claw can be easily attached and removed.  
         [0020]     In the second chuck device of the present invention, it is preferable for the tightening mechanism to be a bolt. Since there is no need to stop rotation, a single bolt used as the tightening mechanism for a single support piece is sufficient. When a bolt is used, it is preferable for a slit to be formed on the attachment base of the chuck claw to allow the bolt to pass through. By passing through the bolt through this type of slit, the attachment base can be inserted deeply into the gap between the bearing surface and the support piece without removing the bolt. Thus, the chuck claw can be more easily attached and removed.  
         [0021]     It is also possible to have a chuck bearing disposed on the arm to receive reaction generated on the chuck claw during the grasping action. The bearing surface may be formed to connect with a side of the chuck bearing section that comes into contact with the chuck claw. The bolt can be set up to attach to the bearing surface in such a direction that, going toward a rear end of the arm, the bolt extends from the bearing surface toward a back surface relative to a side of the arm in contact with the chuck claw. With this structure, an adequate threading depth for the bolt can be provided even if the chuck bearing is thin.  
         [0022]     Furthermore, it is also possible to have an arm shaft rotatably supporting the arm to be disposed behind the bearing surface, and to have the bolt screwed in between the bearing surface and the arm shaft. As a result, a deep threading depth for the bolt can be provided while avoiding the arm shaft.  
         [0023]     It is also possible to have left and right arms, a bearing surface disposed inward from each arm, the bolts passing through the support pieces from inward of the arms being screwed into the arm, and slits being disposed at ends of the chuck claws to allow insertion of a tool used to manipulate the bolts. With this structure, the slit toward the end of the chuck claw can be used to insert a tool such as a wrench. This allows a bolt hidden between the chuck claws to be easily and adequately manipulated.  
         [0024]     It is also possible to have a spring mechanism disposed between the support pieces attached to the bearing surfaces of the arms to draw the support pieces toward each other. In this case, loosening the bolt will result in the support piece being pulled by the spring mechanism away from the bearing surface. As a result, the attachment base of the chuck claw can be easily pulled out from the gap between the support piece and the bearing surface.  
         [0025]     The chuck claw can be formed from various materials, but it is preferable for the chuck claw to be metal. If metal is used, the chuck claw can be made thin while still maintaining adequate strength. The elasticity of the chuck claw can be used to improve the ability of the chuck claws to handle different shapes and sizes of the object to be grasped. Also, by making the chuck claw thin, when multiple chuck devices are used, the pitch between the chuck devices can be reduced, thus conserving space.  
         [0026]     In the chuck claw of the present invention, a grasping section performing grasping actions is formed on a first end; and an attachment base curved to form a cylindrical surface is formed on a second end. This type of chuck claw can be used suitably in the second chuck device of the present invention.  
         [0027]     In the chuck claw of the present invention, it is also possible to have a slit extending in a perimeter direction of a cylindrical surface defined by the attachment base disposed on the attachment base. Also, a slit that divides the grasping section along a direction of an axis of a cylindrical surface defined by the attachment base can be formed on the grasping section.  
         [0028]     Furthermore, a second conveyor device according to the present invention includes: a mobile body capable of pivoting around a predetermined center; and a chuck device. A plurality of the chuck devices are disposed along an outer perimeter of the mobile body. With this type of conveyor device, effective use can be made of the advantage of the chuck device of the present invention in that the chuck claw can be easily attached and removed.  
         [0029]     The above, and other objects, features and advantages of the present invention will become apparent from the following description read in conjunction with the accompanying drawings, in which like reference numerals designate the same elements.  
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0030]      FIG. 1  is a plan drawing of a starter wheel device in which chuck devices of the present invention are used.  
         [0031]      FIG. 2  is a side-view drawing of a chuck device from  FIG. 1 .  
         [0032]      FIG. 3  is a cross-section drawing along the line III-III in  FIG. 2 .  
         [0033]      FIG. 4  is a drawing of the chuck device as seen from the arrow IV in  FIG. 2 .  
         [0034]      FIG. 5  is a cross-section drawing along the line V-V in  FIG. 3 .  
         [0035]      FIG. 6  is a cross-section drawing along the line VI-VI in  FIG. 5 .  
         [0036]      FIG. 7  is a drawing showing the chuck device as seen from the arrow VII in  FIG. 2 .  
         [0037]      FIG. 8A  is a cross-section drawing along the line VIII-VIII in  FIG. 5 , with the chuck bearings closed.  
         [0038]      FIG. 8B  is a cross-section drawing along the line VIII-VIII in  FIG. 5 , with the chuck bearings open.  
         [0039]      FIG. 9  is a cross-section drawing along the line IX-IX in  FIG. 5 .  
         [0040]      FIG. 10  is a simplified drawing as seen from the end of the chuck device.  
         [0041]      FIG. 11  is a perspective drawing of a chuck claw.  
         [0042]      FIG. 12  is a detail drawing of the area around the entry position in  FIG. 1 .  
         [0043]      FIG. 13  is a detail drawing showing a bottle not being deposited at the first exit position in  FIG. 1 .  
         [0044]      FIG. 14  is a detail drawing showing a bottle being deposited at the first exit position in  FIG. 1 .  
         [0045]      FIG. 15  is a detail drawing showing a bottle being deposited at the second exit position in  FIG. 1 .  
         [0046]      FIG. 16  is a cross-section drawing along an arm shaft in another embodiment that uses a torsion coil spring as a biasing mechanism.  
         [0047]      FIG. 17  is a drawing showing a chuck device as seen from arrow XVII in  FIG. 16 .  
         [0048]      FIG. 18  is a plan drawing of a chuck device from  FIG. 16 .  
         [0049]      FIG. 19  is a cross-section drawing along the line XIX-XIX from  FIG. 16 .  
         [0050]      FIG. 20  is a cross-section drawing of the chuck device from  FIG. 16  corresponding to the view in  FIG. 5 .  
         [0051]      FIG. 21  is a drawing showing another example of a tightening mechanism for a support piece. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0052]      FIG. 1  is a plan drawing of a star wheel for conveying beer bottles in which a chuck device of the present invention is implemented. A star wheel device  1  is formed as an exit star wheel device, e.g., an inspection device used to inspect bottles BT. Bottles BT are received at an entry position P 1  from a separate star wheel device  2  that support bottles BT being inspected. The bottles BT are sent out from a first exit position P 2  or a second exit position P 3  to a first conveyor  3  or a second conveyor  4 . Multiple chuck devices  5 , . . . ,  5  for supporting the bottles BT are disposed along the outer perimeter of the star wheel device  1  at a fixed pitch.  
         [0053]     As shown in  FIG. 2 , the chuck device  5  is equipped with a base  10  and a chuck claw  50  for grasping the bottle BT. The base  10  is secured to the outer perimeter of a wheel (moving body)  6  of the star wheel device  1  using a securing structure  7  such as a bolt. The wheel  6  is rotated around a wheel center Cw by a drive device, not shown in the figure, in a predetermined rotation direction (indicated by arrow R in  FIG. 1 ). Thus, the chuck devices  5  are also rotated around the wheel center Cw along with the wheel  6 .  
         [0054]     A guide  13  is attached to the base  10 . The guide  13  is equipped with a guide surface  13   a  curved along the outer perimeter of the bottle BT. Taking into account the tolerance of the diameter of the bottle BT to be grasped by the chuck device  5 , the curvature radius of the guide surface  13   a  of the guide  13  is set slightly larger than the radius of the bottle BT. If the chuck device  5  is set up to handle bottles BT of multiple sizes, the guide  13  is either set up for the bottles BT with the maximum diameter or guides  13  can be set up according to the specific type of bottle BT. In this embodiment, the guide  13  can be omitted if the chuck claw  50  can adequately constrain the bottles BT.  
         [0055]     As shown in  FIG. 3  through  FIG. 6 , left and right arms  15 L,  15 R are attached on the upper surface side of the base  10  so that it can rotate around upwardly extending arm shafts  16 L,  16 R. The arm shafts  16 L,  16 R are disposed in symmetrical positions relative to a reference line CL connecting the center Cb of the bottle BT and the wheel center Cw (see  FIG. 1 ). The upper ends of the arm shafts  16 L,  16 R are connected by a top plate  14  and bolts  14   a.  As shown in  FIG. 2 , the guide  13  is attached to the top plate  14  as well. In this embodiment, the “left” and “right” of the chuck device  5  is defined in terms of when the chuck device  5  is viewed along the reference line CL from the wheel center Cw side. Thus, the side above the reference line in  FIG. 3  and the side to the right in  FIG. 4  correspond to the left side of the chuck device  5 .  
         [0056]     As shown in  FIG. 3 ,  FIG. 5 , and  FIG. 6 , a roller shaft  17  is attached at the inside of the arm  15 L and parallel to the arm shaft  16 L. A first roller  18  is rotatably attached at the outer perimeter of the lower section of the roller shaft  17 . A bracket  20  is secured using a bolt  20   a  to the lower surface side of the base  10 . A cam shaft  21  extending up and down is rotatably attached to the bracket  20 . The cam shaft  21  is disposed along the reference line CL and away from the roller shaft  17  toward the wheel center Cw (to the left in  FIG. 5 ). As shown in  FIG. 7 , the lower end of the cam shaft  21  projects below the base  10 , and a cam drive lever  22  is attached to the projected section so that it rotates integrally with the cam shaft  21 . A cam drive roller  23  is attached to the end of the cam drive lever  22  as an operating member that allows the cam drive roller  23  to rotate around a support shaft (bolt)  24 .  
         [0057]     As shown in  FIG. 5 , an arm drive cam  25  is attached to the upper end of the cam shaft  21  so that it rotates integrally with the cam shaft  21 . As shown in detail in  FIGS. 8A and 8B , the arm drive cam  25  is equipped with a cam surface  26  that comes into contact with the first roller  18 . The cam surface  26  is formed by smoothly connecting a first cavity  26   a,  a second cavity  26   b  serving as a support section, and a projection  26   c  disposed therebetween. The curvature radii of the cavities  26   a,    26   b  are the same as or slightly greater than the radius of the first roller  18 . The distance from the rotation center of the cam shaft  21  to the cam surface  26  is shortest at the bottom of the first cavity  26   a  and is greatest near the boundary between the projection  26   c  and the second cavity  26   b.  The distance from the rotation center of the cam shaft  21  to the bottom of the second cavity  26   b  is adequately larger than the distance from the rotation center of the cam shaft  21  and the bottom of the first cavity  26   a.    
         [0058]     As shown in  FIG. 3  through  FIG. 9 , an arm drive section (second drive section)  28  is disposed on the right arm  15 R so that it faces the cam shaft  21 . A cam surface  30  is disposed on the arm drive section  28 . A second roller  31  is rotatably attached to the outer perimeter of the roller shaft  17  at a position aligned with the cam surface  30 . A post  32  is disposed behind the left arm  15 L, and the top plate  14  is secured to the upper end of the post  32  (see  FIG. 5 ). As shown in  FIG. 9 , a spring bearing cavity  32   a  is disposed on the post  32 , and a coil spring  33  is attached in a compressed state between the spring bearing cavity  32   a  and a spring bearing cavity  15   a  formed at the back end side of the right arm  15 R. The post  32  is connected to the base  10  by way of the top plate  14  and the arm shafts  16 L,  16 R and serves as part of the supporting structure for the arms  15 L,  15 R. As a result, the biasing mechanism, in the form of the spring  33 , disposed between the supporting structure pushes the chuck claw  50  of the arm  15 L in the closing direction. A bolt  34  is attached to the post  32  to guide the inner perimeter of the coil spring  33 .  
         [0059]     As shown in  FIG. 3 , a coil spring  35  is attached in a compressed state as a separate biasing mechanism between spring bearings  15   b,    15   c  of the arms  15 L,  15 R below the coil spring  33 . The repulsion of the coil springs  33 ,  35  bias the arms  15 L,  15 R around the arm shafts  16 L,  16 R so that chuck bearings  40  at the ends of the arms are brought toward each other (i.e., in the direction toward the reference line CL). As a result, the cam surface  30  is pushed into the second roller  31 , and the first roller  18 , which is co-axial to the second roller  31 , is pushed into the cam surface  26  of the arm drive cam  25 . Thus, the first roller  18  and the second roller  31  move around the arm shaft  16 L in tandem with the rotation of the arm drive cam  25 , and this is accompanied by the rotation of the arm  15 L around the arm shaft  16 L. Also, the arm drive section  28  rotates around the arm shaft  16 R in tandem with the movement of the second roller  31 , and this causes the arm  15 R to also rotate around the arm shaft  16 R.  
         [0060]     As shown in  FIG. 8A , when the first roller  18  is engaged with the first cavity  26   a  of the cam surface  26 , the cam shaft  21  is positioned between the arm shafts  16 L,  16 R and on the reference line CL, and the chuck bearings  40  at the ends of the arms  15 L,  15 R are closed. As shown in  FIG. 8B , when the arm drive cam  25  rotates so that the first roller  18  moves toward the second cavity  26   b  of the cam surface  26 , the cam shaft  21  is pushed toward the outer perimeter of the wheel  6 , and the arms  15 L,  15 R rotate around the arm shafts  16 L,  16 R so that the chuck bearings  40  are opened. When the first roller  18  moves past the projection  26   c  and engages with the second cavity  26   b,  the first roller  18  stays engaged with the second cavity  26   b,  working against the coil springs  33 ,  35 , which provide bias in the direction of closing the arms  15 L,  15 R. However, when the first roller  18  applies enough rotation moment to the arm drive cam  25  to go past the projection  26   c,  the springs  33 ,  35  cause the cam  25  to rotate to a position where the first cavity  26   a  and the first roller  18  engage.  
         [0061]     In the description below, the position of the arm drive cam  25  shown in  FIG. 8A  will be referred to as the constrained position and the position shown in  FIG. 8B  will be referred to as the released position. The cam drive roller  23  shown in  FIG. 7  is associated with the arm drive cam  25  in a manner such that it is retracted toward the wheel center Cw when the arm drive cam  25  is in the constrained position, and is displaced toward the outer perimeter side of the wheel  6  when the arm drive cam  25  is in the released position.  
         [0062]     Next, the attachment structure for the chuck claws  50  will be described. As shown in  FIG. 3  through  FIG. 9 , bearing surfaces  41  are formed as cylindrical indentations on the inner surface sides of the base ends of the chuck bearings  40  of the arms  15 L,  15 R. A threaded hole  42  is formed on each of the bearing surfaces  41 . The threaded holes are formed diagonally into the arms  15 L,  15 R so that, going from inside to outside of the arms  15 L,  15 R, the threaded holes  42  are recessed radially inward. As shown in  FIG. 10 , a cylindrical support piece  43  is attached to the bearing surface  41  by threading a single bolt  44  from the inside of the arms  15 L,  15 R. The chuck claws  50  are mounted to the ends of the arms  15 L,  15 R using these support pieces  43 . Coil springs  45 ,  45 , serving as spring mechanisms, are stretched out between the upper ends and the lower ends of the support pieces  43 .  FIG. 9  shows the coil spring  45  at the upper end of the support pieces  43 . A section of the lower coil spring  45  is shown in  FIG. 3 .  
         [0063]     The chuck claws  45  are formed from by metalworking on thin, highly rigid sheets such as stainless steel. As shown in  FIG. 11 , the chuck claw  50  is equipped with a grasping section  51  for grasping the bottle BT and an attachment base  52  for attachment to the arms  15 L,  15 R. The attachment base  52  is curved so that it extends along the bearing surface  41 , and a slit  53  is formed at roughly the center of its vertical axis and extends parallel the perimeter of the attachment  52 . A slit  54  is formed in a similar manner on the side of the grasping section  51  as well. The slit  54  divides the grasping section  51  into upper and lower sections. The slit  54  on the grasping section  51  side extends across the center line of the threaded hole  42 , and the width of the slit  54  is set to be large enough to allow insertion of a tool to manipulate the bolt  44  (e.g., a hex wrench). As indicated by the dotted lines in  FIG. 11 , a stopping member  50   a  may be disposed on the inner surface of the grasping section  51 .  
         [0064]     The attachment of the chuck claws  50  will now be described. The bolt  44  is loosened so that a gap somewhat larger than the thickness of the chuck claw  50  is formed between the support piece  43  and the bearing surface. The attachment base  52  is inserted in the gap between the support piece  43  and the bearing surface  41  while turning the chuck claw  50  along the bearing surface  41 . The bolt  44  is passed through the slit  53 . The bolt  44  is then tightened so that the attachment base  52  of the chuck claw  50  is firmly clamped between the bearing surface  41  and the support piece  43 . The chuck claw  50  can be removed by loosening the bolt  44  and pulling out the attachment base  52  of the chuck claw  50  from between the support piece  43  and the bearing surface  41 .  
         [0065]     With the chuck device  5  described above, the operations of the arms  15 L,  15 R can be varied by changing the shape of the cam surface  30 . In this example, the shape of the cam surface  30  is set up so that the chuck claws  50  move symmetrically relative to the reference line CL. However, it is also possible to assign different operations to the chuck claws  50 ,  50 , e.g., to have one of the chuck claws  50  open first, by changing the shape of the cam surface  30 .  
         [0066]     As shown in  FIG. 1 , operation sections  60 ,  70 ,  80  are disposed at entry position P 1  and exit positions P 2 , P 3 , respectively. As shown in  FIG. 12 , a cam block  61  is disposed on the operation section  60  at the entry position P 1 . The cam block  61  is secured at a fixed position relative to the rotation of the wheel  6  by being attached to a fixed section, e.g., the base, of the starter wheel device  1 . A cam surface  61   a  facing the wheel center Cw is formed on the cam block  61 . When the arm drive cam  25  of the chuck device  5  is in the free position, the cam surface  61   a  comes into contact with the cam drive roller  23 , and, taking advantage of the rotation of the wheel  6  to a position where the first roller  18  can disengage from the second cavity  26   b  of the arm drive cam  25 , the cam drive roller  23  is sent toward the wheel center Cw.  
         [0067]     As shown in  FIG. 13  and  FIG. 14 , a rotor  71  is disposed as a movable section of the operation section  70  at the exit position P 2 . The rotor  71  is disposed so that it can rotate around a vertical axis, and on the outer perimeter thereof are formed a pair of arms  71   a,    71   a  that can come into contact with the cam drive roller  23 . Also, as shown in  FIG. 1 , the rotor  71  is connected to an output shaft  73   a  of a servo motor  73  by way of a transmission mechanism  72 . A belt-type transmission device or the like is used for the transmission mechanism  72 . Driven by the servo motor  73 , the rotor  71  rotates between an active position, where the arm  71   a  is projected toward the chuck device  5  ( FIG. 14 ), and a stand-by position, where the arms  71   a  are retracted away from the active position toward the wheel center Cw ( FIG. 13 ). As shown in  FIG. 14 , when the rotor  71  is at the active position, the arm  71   a  comes into contact with the cam drive roller  23  when the arm drive cam  25  of the chuck device  5  is in the constrained position. The rotation of the wheel  6  up to when the arm drive cam  25  moves to the free position is used to send the cam drive roller  23  toward the outer perimeter of the wheel  6 . When the rotor  71  is at the stand-by position, the arm  71   a  is retracted further toward the wheel center Cw than the cam drive roller  23  regardless of the position of the arm drive cam  25 .  
         [0068]     Next, the operations of the starter wheel device  1  presented above will now be described. First, the chuck devices  5  are brought out one by one to the entry position P 1  of the starter wheel device  1  as the wheel  6  rotates. The arm drive cam  25  is in the free position in front of the entry position P 1 , and the chuck claws  50  are opened. When the chuck device  5  is brought to the entry position P 1  by the wheel  6 , the cam drive roller  23  comes into contact with the cam surface  61   a  and is pushed toward the wheel center Cw. As a result, the first roller  18  disengages from the second cavity  26   b  of the arm drive cam  25  and the arm drive cam  25  returns to its constrained position. This closes the chuck claws  50 . In tandem with the closing of the chuck claws  50 , the bottle BT is passed on from the star wheel device  2  to between the chuck claws  50 , and the bottle BT is grasped by the chuck claws  50 ,  50  (see  FIG. 12 ).  
         [0069]     As the wheel  6  rotates, the bottle BT grasped by the chuck claws  50  is first conveyed to the first exit position P 2 . At the first exit position P 2 , the rotor  71  is kept at the stand-by position shown in  FIG. 13 . If the bottle BT is a bottle BT that should be sent out to the first conveyor  3 , the servo motor  73  is driven to move the arm  71   a  to the active position shown in  FIG. 14  when the cam drive roller  23  of the chuck device  5  is to be sent out to the first exit position P 2 . As a result, the cam drive roller  23  comes into contact with the arm  71   a  and is pushed toward the outer perimeter, causing the arm drive cam to be moved from the constrained position to the free position. Thus, the chuck claws  50  open and the bottle BT is sent out to the first conveyor  3 . After the bottle BT is sent out, the rotor  71  returns to the stand-by position before the roller  23  reaches the rotation range of the arm  71   a.    
         [0070]     If the bottle BT sent to the first exit position should not be sent out to the first conveyor  3 , the servo motor  73  is not activated and the rotor  71  stays in the stand-by position. Thus, the cam drive roller  23  of the chuck device  5  holding the bottle BT is not able to come into contact with the arm  71   a,  and the arm drive cam  25  is kept in the constrained position. Thus, as shown in  FIG. 13 , the bottle BT that should not be sent out is not released from the chuck claw  50 , passes by the first exit position P 2  and heads toward the second exit position P 3 .  
         [0071]     As shown in  FIG. 15 , the cam surface  81   a  comes into contact with the cam drive rollers  23  of the chuck devices  5  sent one by one to the second exit position P 3  as the wheel  6  rotates, and every arm drive cam  25  is switched from the constrained position to the release position. As a result, the chuck claws  50  are always opened at the second exit position P 3 . Thus, the bottles BT transported to the second exit position P 3  are sent out to the second conveyor  4 .  
         [0072]     With the star wheel device  1  of this embodiment as described above, the bottles BT can be selectively sent out to the first exit conveyor  3  or the second exit conveyor  4  by switching the position of the rotor  71  installed at the first exit position P 2 . For example, when the bottles BT and their contents are inspected before the star wheel device, the rotor  71  can be switched from the stand-by position to the active position when a bottle BT that passed the inspection reaches the first exit position P 2 . This allows the good products that have passed the inspection to be sent to the first exit conveyor  3  while the defective products that did not pass the inspection are sent to the second exit conveyor  4 .  
         [0073]     On the other hand, if the rotor  71  is kept in the stand-by position when a bottle BT that has passed the inspection is sent to the first exit position P 2  and the rotor  71  is put in the active position when a failed bottle BT is sent to the first exit position P 2 , the defective products that did not pass the inspection can be sent out to the first exit conveyor  3  and the good products that passed the inspection can be sent out to the second exit conveyor  4 . More specifically, the rotor  71  can be kept in the stand-by position by default so that the chuck claws  50  are kept open at the first exit position P 2 . At the second exit position P 3 , the cam block  81  can be used to open the chuck claws  50  to release the bottle BT,. When there is a need to separate the bottles BT that did not pass the inspection or the like, the rotor  71  can be switched to the active position to open the chuck claws  50  when the chuck device  5  holding the bottle BT reaches the first exit position P 2 . The rotor  71  then needs to return to the stand-by position before the next bottle BT reaches the first exit position P 2 .  
         [0074]     The star wheel device  1  and the chuck device  5  of this embodiment provide the following operations and advantages.  
         [0075]     (1) Everything from the cam drive roller  23  of the chuck device  5  to the cam surface  30  is completely mechanical. This provides superior responsiveness and reliability in the opening and closing actions of the chuck claws  50  and allows the wheel  6  to be operated at higher speeds.  
         [0076]     (2) Since the cam surfaces  26 ,  30  are pressed against the opposing (driven) rollers  18 ,  31  using the coil springs  33 ,  35 , there is no need to mechanically connect the arm drive cam  25  to the arms  15 L,  15 R, which are driven by the arm drive cam  25 . This makes assembly and disassembly easy. Also, the cam surfaces  26 ,  30  are placed into contact with the rollers  18 ,  31 , so friction resistance is reduced and operations can be made smoother. In the present invention, it is possible to convert the rotation of the cam shaft  21  using a linkage mechanism to open and close the arms  15 L,  15 R. However, if a linkage mechanism is to be used, connections must be made between the links themselves and the links to the arms and the like, increasing the number of assembly steps.  
         [0077]     (3) Since the second cavity  26   b  is formed on the cam surface  26  to keep the arm drive cam  25  in the release position in opposition to the coil springs  33 ,  35 , keeping the chuck claws  50  open does not require, on the star wheel device  1  side, keeping the cam drive roller  23  continuously at a position corresponding to the release position of the arm drive cam  25 . Thus, to keep the chuck claws  50  in an open state, the rotor  71  and the cam  81  need only push the roller  23  in until the first roller  18  goes past the projection  26   c  and enters the second cavity  26   b,  and the cam  81  and the like do not need to keep pushing the roller  23  once the arm drive cam has switched to the release position. If this type of self-supporting feature were not present for the arm drive cam  25 , it would be necessary to design the cam  61  so that, first, the chuck claws  50  are opened at the entry position P 1 , and then the chuck claws  50  are closed when the bottle BT is received. This would make the cam  61  more complicated.  
         [0078]     (4) In order to rotationally bias the arms  15 L,  15 R in the direction of closing the chuck claws  50 , it is necessary to provide the coil spring  35  between the arms  15 L,  15 R and also to provide the coil spring  33  between one of the arms  15 R and the side on which the arms  15 L,  15 R are supported (the post  32 ), thus biasing the arm  15 R in the direction that pushes the cam surface  30  thereof against the second roller  31 . If only the coil spring  35  were to be provided, the arms  15 L,  15 R could pivot around the arm shafts  16 L,  16 R clockwise (in the view in  FIG. 3 ), disengaging the second roller  31  and the cam surface  30 , and leading to instability in the chuck claws  50 ,  50 . However, by using the coil spring  33  to bias the arm  15 R around the arm shaft  16 R in the counter-clockwise direction, the arm  15 R is prevented from pivoting in this manner, and the contact between the cam surface  30  and the second roller  31  can be maintained.  
         [0079]     (5) Since the servo motor  73  is used to drive the rotor  71 , the rotor  71  can be operated at high speeds and accurately, thus allowing the invention to handle high speeds for the wheel  6 .  
         [0080]     (6) Furthermore, the attachment structure for the chuck claws  50  according to this embodiment provides the following advantages. First, since the chuck claw  50  is clamped between the cylindrical bearing surface  41  and the cylindrical support piece  43 , the use of only one bolt  44  does not lead to the chuck claw  50  rotating around the bolt  44 . Also, since a slit  53  is disposed to allow the bolt  44  to be inserted, there is no need to detach the support piece  43  or the bolt  44  from the arms  15 L,  15 R when removing or attaching the chuck claws  50 . Thus, the chuck claws  50  can be attached and removed easily. When the bolt  44  is removed, the pull from the coil spring  45  draws the support piece  43  away from the bearing surface  41 , thus making mounting of the attachment base  52  of the chuck claw  50  even easier.  
         [0081]     Since the chuck claws  50  are mounted inward from the arms  15 L,  15 R, the reaction from the force involved when the chuck claws  50  grasp the bottle BT can be applied to the arms  15 L,  15 R and not to the bolt  44 . This is useful in maintaining the rigidity of the attachment section of the chuck claws  50 . The slit  54  toward the grasping section  51  can be used to insert a tool (wrench) for manipulating the bolt  44 , so even if the chuck claw  50  is attached to one of the arms  15 L,  15 R, the chuck claw  50  for the opposite arm  15 L,  15 R can be easily attached or removed. The slit  54  is needed because the threaded hole  42  is sloped. The reason for providing the slope is as follows.  
         [0082]     Securing the chuck claw  50  firmly requires that an adequate threading depth be provided for the bolt  44 . However, reducing the pitch at which the chuck devices  5  are arranged along the perimeter and increasing the number of chuck devices  5  that can be attached to the wheel  6  requires reducing the thickness of the chuck bearing  40  as much as is possible without losing strength. As a result, orienting the threaded hole  42  to be perpendicular to the chuck bearing  40  will not provide adequate thread depth. On the other hand, since the arm shafts  16 L,  16 R are disposed behind the chuck bearings  40 , forming the threaded holes  42  from the bearing surface  41  along the reference line CL will not provide adequate length for the threaded hole  42 . By extending the threaded hole  42  diagonally outward from the bearing surface  41 , it is possible to maximize the length of the threaded hole  42  within the restricted space.  
         [0083]     Furthermore, since the grasping section  51  is divided into upper and lower sections by the slit  54  of the chuck claw  50 , the grasping section  51  can be formed with different shapes above and below the slit  54  to match the shape of the bottle BT. Also, when the chuck claw  50  is formed from metal such as stainless steel, adequate rigidity can be provided for the grasping section  51  even if it is thin, and more elastic deformation is possible as well. As a result, the chuck claw  50  can be elastically deformed even when grasping bottles BT having different diameters as shown in  FIG. 3 . Thus, the chuck claws  50  can handle bottles BT with different diameters without requiring the chucks  50  to be switched. Of course, it is also possible to switch the chuck claws  50 .  
         [0084]     In the embodiment described above, the base  10 , the arm shafts  16 L,  16 R, the top plate  14 , and the post  32  form a supporting structure. The roller shaft  17 , the first roller  18 , and the second roller  31  form the first drive section. The lever  22 , the cam shaft  21 , the arm drive cam  25 , and the first roller  18  form a motion input mechanism. The second roller  31  and the cam surface  30  form a coupling mechanism. The present invention, however, is not restricted to the embodiment described above, and various different implementations are possible. For example, in the chuck device  5 , it is possible to have multiple vertically arranged levels of chuck claws  50 . Two or more pairs of arms  15 L,  15 R can be provided in vertically arranged levels, with one or more chuck claws being attached to each arm. When multiple vertically arranged levels of the chuck claws  50  are to be provided, it is preferable to optimize the shape of the grasping sections  51  of the chuck claws  50  to match the shape of the bottle BT where it will be grasped by the chuck claws  50 . It is also possible to provide a freely rotatable roller at the inner side of the chuck claws  50 , thus allowing the bottle BT to spin while being grasped by the chuck claws  50  by way of the roller. This type of structure is suited for cases such as when the bottle BT is to be rotated during the inspection step.  
         [0085]     The biasing mechanism for the arms  15 L,  15 R is not restricted to the coil springs  33 ,  35 , and other structures can be used.  FIG. 16  through  FIG. 20  show another embodiment in which a different biasing mechanism is sued. Elements that are the same as those from the embodiment shown in  FIG. 1  through  FIG. 15  are assigned like numerals and corresponding descriptions are omitted.  
         [0086]     In the embodiment shown in  FIG. 16  through  FIG. 20 , the pair of arm shafts  16 L,  16 R project upward from the top plate  14 . To the outer perimeter of the projected sections  16   a  are fitted torsion coil springs  55 , serving as a biasing mechanism, by way of bushes  16   b.  The upper ends of the arm shafts  16 L,  16 R are connected to each other by way of a connecting plate  56  and bolts  57 . On the lower surface side of the connecting plate  56 , a block  58  used as a spring peg is secured with a bolt  58   a.  The tightening force from the bolts  57  is received by the top plate  14  by way of the bushes  16   b,  and this results in the arm shafts  16 L,  16 R being supported between the top plate  14  and base  10 , serving as a supporting structure.  
         [0087]     As shown in  FIG. 18  and  FIG. 19 , a pair of arms  55   b,    55   c  are mounted on each arm shaft  16 L,  16 R by hooking one arm  55   c  to the block  58  and the other arm  55   b  to pins  15   d  disposed on the arms  15 L,  15 R while keeping the pair of arms  55   b,    55   c  slightly open. The opening up of the arms  55   b,    55   c  causes the elastic restoring force generated in a coil section  55   a  to bias the arms  55   b,    55   c  toward each other (indicated by the arrow A in  FIG. 17 ), and this results in the arms  15 L,  15 R also being biased in the direction that closes the chuck claws  50 .  
         [0088]     By using the torsion coil spring  55  as a biasing mechanism in this manner, there is no need to extend the arms  15 L,  15 R behind the arm shafts  16 L,  16 R or to provide the spring bearing hole  15   a  ( FIG. 9 ) or the spring bearings  15   b,    15   c  ( FIG. 3 ) for the coil springs  33 ,  35 . Thus, the rear ends of the arms  15 L,  15 R only extend to where they fit the arm shafts  16 L,  16 R, and the post  32  is eliminated is as well. As a result, the shape of the arms  15 L,  15 R is simplified and the number of parts is reduced. As  FIG. 19  shows, the torsion coil spring is arranged symmetrically relative to the reference line CL. Thus, the arms  15 L,  15 R can be biased symmetrically, and the symmetry of their operations can be improved.  
         [0089]     As  FIG. 16 ,  FIG. 19 , and  FIG. 20  show, the shortening of the arms  15 L,  15 R and the elimination of the post  32  and the coil springs  33 ,  35  creates space behind the roller shaft  17 . The cam shaft  21  is extended upward to fill this space. The upper end of the cam shaft  21  is connected to the top plate  14  using a bolt  59 . As a result, both ends of the cam shaft  21  are supported, and flexure of the cam shaft  21  can be restricted more than in the structure shown in  FIG. 5 .  
         [0090]     Although the embodiments above use a bolt as a tightening mechanism, tightening means is not restricted to this. For example, as shown in  FIG. 21 , a rod  100  can be mounted using the threaded hole  42 , and a spring  101  can be attached in a compressed state between an enlarged section  100   a  and the support piece  43 . This allows the rod  100  and the spring  101  to be used as a tightening mechanism.  
         [0091]     The chuck device of the present invention is suitable for use with a star wheel device, but the present invention is not restricted to this and can be used in different types of conveyor devices in which containers need to be grasped. Also, the chuck device of the present invention is not restricted to a structure in which a pair of arms is opened and closed to grasp an object such as a container. The present invention can use different types of chuck devices. For example, instead of or in addition to having arms open and close, it is also possible to have a chuck device with arms that slide to perform a grasping action. Chuck claws can be attached to the arms according to the present invention in this case as well. The attaching of the chuck claw to the arm according to the present invention can be implemented for cases where a single arm performs a grasping action as well.  
         [0092]     With the first chuck device and conveyor device according to the present invention as described above, the motion of an operation member is first transmitted from a first drive section to an arm, the arm is rotated, and this rotation is transmitted to a second drive section by way of a coupling mechanism. By changing the modes in which motion is converted, the degree of freedom for the operations of the arms can be increased. Also, since everything from the operation member to each of the arms is formed from mechanical mechanisms, the operations are precise and reliable and higher conveyor speeds can be handled. Furthermore, by using cam mechanisms for the motion input mechanism and the coupling mechanism simplifies the structure and provides further improvements in reliability.  
         [0093]     Also, with the second chuck device and conveyor device according to the present invention, simply manipulating a tightening mechanism, e.g., a bolt, allows the chuck claws to be attached and removed and also prevents the chuck claws from rotating. Thus, the chuck claws can be easily attached and removed. In particular, with conveyor devices that use multiple chuck devices, the number of steps involved in attaching and removing the chuck claws can be significantly reduced.  
         [0094]     Having described preferred embodiments of the invention with reference to the accompanying drawings, it is to be understood that the invention is not limited to those precise embodiments, and that various changes and modifications may be effected therein by one skilled in the art without departing from the scope or spirit of the invention as defined in the appended claims.