Patent Publication Number: US-2021190183-A1

Title: Variable pitch device

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is based upon and claims the benefit of priority from Japanese Patent Application No. 2019-229621 filed on Dec. 19, 2019, the contents of which are incorporated herein by reference. 
     BACKGROUND OF THE INVENTION 
     Field of the Invention 
     The present invention relates to a variable pitch device for, in a process of transporting a plurality of workpieces, changing an interval separation between workpieces arranged in parallel from an interval separation at a supply source to an interval separation corresponding to a supply destination and then supplying the workpieces to the supply destination. 
     Description of the Related Art 
     Conventionally, for example, on a factory production line or the like, a workpiece, which is placed on a table, is gripped by a transport device provided with a suction pad at a distal end thereof, and the workpiece is transported to a predetermined position. In recent years, a variable pitch device has been known, which is capable of simultaneously grasping a plurality of workpieces which are arranged in parallel on a table, adjusting the plurality of workpieces to a predetermined interval spacing in accordance with an arrangement condition of a supply destination, and supplying the workpieces to the supply destination. 
     In such a variable pitch device, for example, as disclosed in Japanese Laid-Open Patent Publication No. 2007-105857, a motor is attached to a rear surface of a base plate, and a plate cam which is formed in a disk-like shape, two levers, and a slide shaft are provided on a front surface of the base plate. Additionally, a cam groove is formed in the plate cam, and the plate cam is disposed to be capable of rotating under a driving action of the motor via a rotating shaft provided in the center of the cam groove. The cam groove is formed in an annular shape centered about the rotating shaft. 
     Further, the two levers are disposed so as to be capable of swinging about fulcrums supported on the base plate in the vicinity of upper and lower sides of the plate cam, follower rollers which are inserted into the cam groove of the plate cam are provided on the front surface thereof, and a plurality of roller pins are disposed on the rear surface thereof. 
     Furthermore, the slide shaft extends along a widthwise direction of the base plate, and eight slide blocks are movably retained thereby. In addition, the slide blocks are capable of sliding substantially in parallel with each other, and grooves are formed on the rear surface thereof. Respective roller pins provided on the levers are rotatably engaged with the grooves. 
     In addition, the plate cam is rotated under a driving action of the motor, and by the levers being made to swing about the fulcrums by the respective follower rollers which are coupled to the cam groove, the slide blocks which are connected via the roller pins move in parallel along the slide shaft. Since movement of the slide blocks is symmetrical in the longitudinal direction of the slide shaft, the respective slide blocks undergo movement while always keeping the interval spacing therebetween constant. 
     SUMMARY OF THE INVENTION 
     In the variable pitch device described above, a configuration is provided in which the slide blocks are made to slide by transmitting a rotational driving force of the motor to the plate cam, causing the plate cam to undergo rotation, and causing the levers to swing. Therefore, the configuration for transmitting the rotational driving force from the motor to the slide blocks is complex, and there is a concern of bringing about an increase in the size of the variable pitch device, as well as leading to a steep rise in manufacturing costs. 
     A general object of the present invention is to provide a variable pitch device, which with a simple configuration, is capable of reducing manufacturing costs and decreasing the size of the variable pitch device. 
     An aspect of the present invention is characterized by a variable pitch device comprising a body, a drive unit connected to the body, a plurality of movable fingers disposed movably along a longitudinal direction of the body, and a driving force transmission mechanism configured to transmit a driving force of the drive unit to the movable fingers, the variable pitch device moving the plurality of movable fingers in a manner so that an interval separation between the movable fingers becomes even along the longitudinal direction under a driving action of the drive unit, wherein the driving force transmission mechanism includes a cam plate provided on the body, and configured to be movable in a direction perpendicular to a direction of movement of the movable fingers, and a plurality of cam grooves, which are inclined with respect to the direction of movement, are formed in the cam plate, and portions of the movable fingers are inserted through the cam grooves. 
     According to the present invention, the body constituting the variable pitch device is equipped with the plurality of movable fingers that are capable of being moved along the longitudinal direction, together with the cam plate that is capable of moving in a direction perpendicular to the direction of movement of the movable fingers, and the plurality of cam grooves, which are inclined with respect to the direction of movement, are formed in the cam plate, and portions of the movable fingers are inserted through the cam grooves. 
     In addition, the driving force of the drive unit is transmitted to the cam plate that constitutes the driving force transmission mechanism, and the cam plate is moved in a direction perpendicular to the direction of movement of the movable fingers, whereby the plurality of movable fingers which are inserted respectively through the cam grooves undergo movement in a manner so that the interval separation between the movable fingers becomes even along the longitudinal direction of the body. 
     Accordingly, by providing the cam plate including the cam grooves as a driving force transmission mechanism that transmits the driving force of the drive unit to the plurality of movable fingers, the configuration can be simplified in comparison with a conventional variable pitch device in which the rotational driving force of a motor is transmitted to slide blocks via a plate cam and two levers, and along therewith, it is possible to make the variable pitch device smaller in size and to reduce manufacturing costs. 
     The above and other objects, features, and advantages of the present invention will become more apparent from the following description when taken in conjunction with the accompanying drawings, in which preferred embodiments of the present invention are shown by way of illustrative example. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an external perspective view of a variable pitch device according to a first embodiment of the present invention; 
         FIG. 2  is an external perspective view of the variable pitch device of  FIG. 1  as viewed from another (rear side) direction; 
         FIG. 3  is an exploded perspective view of the variable pitch device shown in  FIG. 1 ; 
         FIG. 4  is a cross-sectional view taken along line IV-IV of  FIG. 1 ; 
         FIG. 5  is a cross-sectional view taken along line V-V of  FIG. 1 ; 
         FIG. 6  is a cross-sectional view taken along line VI-VI of  FIG. 5 ; 
         FIG. 7  is a cross-sectional view taken along line VII-VII of  FIG. 5 ; 
         FIG. 8  is a cross-sectional view taken along line VIII-VIII of  FIG. 5 ; 
         FIG. 9  is an overall cross-sectional view showing a drive unit that constitutes the variable pitch device shown in  FIG. 1 ; 
         FIG. 10  is an external perspective view showing an open state in which movable fingers are opened in the variable pitch device shown in  FIG. 1 ; 
         FIG. 11  is a cross-sectional view taken along line XI-XI of  FIG. 10 ; 
         FIG. 12  is a cross-sectional view taken along line XII-XII of  FIG. 10 ; 
         FIG. 13  is a cross-sectional view taken along line XIII-XIII of  FIG. 12 ; 
         FIG. 14  is a cross-sectional view taken along line XIV-XIV of  FIG. 12 ; 
         FIG. 15  is an external perspective view of a variable pitch device according to a second embodiment of the present invention; 
         FIG. 16  is an exploded perspective view of the variable pitch device shown in  FIG. 15 ; 
         FIG. 17  is an overall front surface view of the variable pitch device shown in  FIG. 15 ; 
         FIG. 18  is a cross-sectional view taken along line XVIII-XVIII of  FIG. 17 ; 
         FIG. 19  is a cross-sectional view taken along line XIX-XIX of  FIG. 17 ; 
         FIG. 20  is an external perspective view showing a closed state in which the movable fingers of the variable pitch device shown in  FIG. 15  approach one another; 
         FIG. 21  is an overall front surface view of the variable pitch device shown in  FIG. 20 ; 
         FIG. 22  is an external perspective view of a variable pitch device according to a third embodiment of the present invention; 
         FIG. 23  is a partially omitted external perspective view of the variable pitch device of  FIG. 22  as viewed from another (rear side) direction; 
         FIG. 24  is an exploded perspective view of the variable pitch device shown in  FIG. 23 ; 
         FIG. 25  is an overall front surface view of the variable pitch device shown in  FIG. 22 ; 
         FIG. 26  is an overall rear surface view of the variable pitch device shown in  FIG. 22 ; 
         FIG. 27  is an overall cross-sectional view showing a drive unit that constitutes the variable pitch device shown in  FIG. 23 ; 
         FIG. 28  is a cross-sectional view taken along line XXVIII-XXVIII of  FIG. 26 ; 
         FIG. 29  is an overall front surface view showing an open state in which movable fingers are opened in the variable pitch device shown in  FIG. 25 ; 
         FIG. 30  is an overall rear surface view of the variable pitch device shown in  FIG. 29 ; 
         FIG. 31  is a cross-sectional view taken along line XXXI-XXXI of  FIG. 30 ; 
         FIG. 32  is an external perspective view of a variable pitch device according to a fourth embodiment of the present invention; 
         FIG. 33  is a partially omitted external perspective view of the variable pitch device of  FIG. 32  as viewed from another (rear side) direction; 
         FIG. 34  is an exploded perspective view of the variable pitch device shown in  FIG. 33 ; 
         FIG. 35  is an overall front surface view of the variable pitch device shown in  FIG. 32 ; 
         FIG. 36  is an overall rear surface view of the variable pitch device shown in  FIG. 32 ; 
         FIG. 37  is a cross-sectional view taken along line XXXVII-XXXVII of  FIG. 36 ; 
         FIG. 38  is an overall cross-sectional view showing a drive unit that constitutes the variable pitch device shown in  FIG. 33 ; 
         FIG. 39  is an overall front surface view showing an open state in which movable fingers are opened in the variable pitch device shown in  FIG. 35 ; 
         FIG. 40  is an overall rear surface view of the variable pitch device shown in  FIG. 39 ; 
         FIG. 41  is a cross-sectional view taken along line XLI-XLI of  FIG. 40 ; 
         FIG. 42  is an overall rear surface view of a variable pitch device according to a first modification in which a first stopper mechanism is provided in the variable pitch device shown in  FIG. 33 ; 
         FIG. 43  is an overall rear surface view showing a state in which a sub-cam plate in the variable pitch device of  FIG. 42  has been moved and placed in engagement with the first stopper mechanism; 
         FIG. 44  is an overall rear surface view of a variable pitch device according to a second modification in which a second stopper mechanism is provided in the variable pitch device shown in  FIG. 33 ; 
         FIG. 45  is an overall rear surface view showing a state in which movable fingers in the variable pitch device of  FIG. 44  are engaged by the second stopper mechanism; 
         FIG. 46  is an overall rear surface view of a variable pitch device according to a third modification in which a third stopper mechanism is provided in the variable pitch device shown in  FIG. 33 ; 
         FIG. 47  is an overall rear surface view showing a state in which a sub-cam plate in the variable pitch device of  FIG. 46  has been moved and placed in engagement with the third stopper mechanism; and 
         FIG. 48  is an overall rear surface view showing an open state in which movable fingers are opened in the variable pitch device shown in  FIG. 46 . 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     As shown in  FIGS. 1 to 8 , a variable pitch device  10  according to a first embodiment of the present invention includes a body  12 , a drive unit  14  mounted on a rear surface of the body  12 , a plurality of movable fingers  16   a  to  16   d  which are disposed so as to be capable of moving along a longitudinal direction (the direction of arrows A 1  and A 2 ) of the body  12 , and a driving force transmission mechanism  18  that transmits a driving force of the drive unit  14  to the movable fingers  16   a  to  16   d . In this instance, a description will be given concerning a case in which four movable fingers  16   a  to  16   d  are provided. In addition, the above-described variable pitch device  10  is attached, for example, to the distal end of an arm in a non-illustrated transport device, and suction units P (see FIGS.  6  to  8 ) are mounted and used respectively on the movable fingers  16   a  to  16   d.    
     The body  12  is formed in an elongate shape along the longitudinal direction (the direction of arrows A 1  and A 2 ), and is equipped with a main body portion  20  that retains the movable fingers  16   a  to  16   d  in a movable manner, and a cover member  22  that is mounted on a rear side (in the direction of the arrow B 1 ) of the main body portion  20 . 
     The main body portion  20  includes a finger accommodating section  24  which is formed on the front side (in the direction of the arrow B 2 ) perpendicular to the longitudinal direction of the body  12  and in which the movable fingers  16   a  to  16   d  are accommodated, and an accommodation chamber  26  formed on the rear side (in the direction of the arrow B 1 ) opposite to the front side. 
     The finger accommodating section  24  is recessed at a predetermined depth from first end surfaces  28  on the front side and is formed substantially in parallel with the first end surfaces  28 , and a pair of engagement grooves  30  (see  FIG. 8 ) recessed in a vertical direction (height direction) are formed at a position on the rear side (in the direction of the arrow B 1 ) with respect to the side of the first end surfaces  28 . Stated otherwise, as shown in  FIG. 8 , the finger accommodating section  24  is formed so as to be wider in the height direction (in the direction of arrows C 1  and C 2 ) on the rear side (in the direction of the arrow B 1 ) thereof. Additionally, the engagement grooves  30 , in the same manner as the finger accommodating section  24 , extend from a later-described fixed finger  32  to both ends in the longitudinal direction along the longitudinal direction of the body  12 . 
     Further, the fixed finger  32  is formed at the center in the longitudinal direction of the main body portion  20 . The fixed finger  32  is elongated in the vertical direction (the direction of arrows C 1  and C 2 ) with a substantially rectangular cross section, is disposed in a manner so as to divide the finger accommodating section  24  into two parts in the longitudinal direction (the direction of arrows A 1  and A 2 ), and is formed so as to connect the upper first end surface  28  (in the direction of the arrow C 1 ) and the lower first end surface  28  (in the direction of the arrow C 2 ) that are divided by the finger accommodating section  24 . 
     In addition, the fixed finger  32  protrudes slightly more outward (in the direction of the arrow B 2 ) than the first end surfaces  28  (see  FIG. 6 ), while in addition, the protruding portion thereof includes a first mounting surface  34  substantially in parallel with the first end surfaces  28 . For example, a suction unit P for attracting a workpiece is attached to the first mounting surface  34  via mounting holes  34   a.    
     As shown in  FIG. 4  and  FIGS. 6 to 8 , the accommodation chamber  26  is recessed at a predetermined depth with respect to a second end surface  36  on the rear side of the main body portion  20 , is formed substantially in parallel with the second end surface  36 , and is formed at a constant depth along the longitudinal direction (the direction of arrows A 1  and A 2 ) of the main body portion  20 . Further, as shown in  FIG. 4 , the outer edge of the accommodation chamber  26  is covered by an outer wall of the main body portion  20  on the rear side, and a set of convex portions  38  having a rectangular cross section are disposed in a downwardly protruding manner on the outer wall above the accommodation chamber  26  (in the direction of the arrow C 1 ). On the other hand, on the outer wall below the accommodation chamber  26  (in the direction of the arrow C 2 ), corner portions  40  that bulge outward in a tapered shape are formed at the corners thereof. 
     Further, as shown in  FIGS. 1 to 8 , the main body portion  20  includes a separating wall  42  that separates the finger accommodating section  24  and the accommodation chamber  26 , and a pair of guide holes  44  are formed in the separating wall  42  at substantially central positions in the height direction. The guide holes  44  are formed in straight line shapes with the fixed finger  32  being at the center along the longitudinal direction (the direction of arrows A 1  and A 2 ) of the main body portion  20 , extend from the fixed finger  32  to the vicinity of both ends of the main body portion  20  in the longitudinal direction, and are formed to penetrate through the separation wall  42  so as to provide communication between the finger accommodating section  24  and the accommodation chamber  26 . 
     As shown in  FIGS. 1 to 4  and  FIGS. 6 to 8 , the cover member  22  is formed in a plate-like shape that entirely covers the rear side (in the direction of the arrow B 1 ) of the main body portion  20 , and a hole  46  extending in the height direction (in the direction of arrows C 1  and C 2 ) perpendicular to the longitudinal direction is formed in the center of the cover member  22  in the longitudinal direction. The hole  46  is formed in an elongate and linear shape in the height direction of the cover member  22 , and due to being formed so as to penetrate through the cover member  22 , provides communication between the accommodation chamber  26  of the main body portion  20  and the exterior. 
     In addition, the accommodation chamber  26  is placed in a covered state by the cover member  22  being fixed by a plurality of mounting bolts  48  in a state of being mounted on the rear side of the main body portion  20 . 
     As shown in  FIGS. 1 to 5  and  FIG. 9 , the drive unit  14  is made up from, for example, an electric actuator which is capable of moving a rod (output shaft)  58  forward and rearward in the axial direction (the direction of arrows C 1  and C 2 ) under an energizing action. As shown in  FIG. 9 , the drive unit  14  includes a housing  50 , a motor  52  accommodated in the interior of the housing  50 , a feed screw  54  rotatably provided in the interior of the housing  50 , a transmission mechanism  56  that transmits a driving force of the motor  52  to the feed screw  54 , the rod  58  that moves forward and rearward along the housing  50  under a rotating action of the feed screw  54 , and an end block  60  connected to a distal end of the rod  58 . 
     Additionally, as shown in  FIG. 2 , on the rear side (in the direction of the arrow B 1 ) of the body  12 , the drive unit  14  is arranged in a manner so as to be perpendicular to the longitudinal direction (in the direction of arrows A 1  and A 2 ) of the body  12 , and is connected to the cover member  22  by non-illustrated bolts or the like. 
     As shown in  FIG. 9 , the housing  50  includes first and second bore portions  62  and  64  formed in a hollow shape, and the first bore portion  62  and the second bore portion  64  are disposed respectively along the height direction (in the direction of arrows C 1  and C 2 ) perpendicular to the longitudinal direction (the direction of arrows A 1  and A 2 ) of the body  12  and are disposed adjacently in the longitudinal direction. In addition, the motor  52  is accommodated in the interior of the first bore portion  62 , and the feed screw  54 , a slider  76 , and the rod  58  are accommodated in the interior of the second bore portion  64 . 
     Further, a pulley cover  66  is connected to upper end portions of the first and second bore portions  62  and  64 , and connects and closes the first bore portion  62  and the second bore portion  64 , and a portion of the transmission mechanism  56  is accommodated in the interior thereof. 
     The feed screw  54  is made up from a shaft body having a predetermined length along the axial direction (the direction of arrows C 1  and C 2 ), and a screw thread is formed on the outer circumferential surface thereof, the feed screw  54  being accommodated inside the second bore portion  64  so as to extend in the height direction, and being rotatably supported via bearings  68 . 
     The transmission mechanism  56  includes a drive pulley  70  connected to a drive shaft  95  of the motor  52 , a driven pulley  72  connected to one end portion of the feed screw  54 , a timing belt  74  placed between the drive pulley  70  and the driven pulley  72 , and the slider  76  that is screw-engaged on the outer circumference of the feed screw  54 . 
     The slider  76  is made up from a cylindrical body having a female screw thread formed on an inner circumferential surface thereof, and is screw-engaged with the male screw thread of the feed screw  54  that is inserted in the interior thereof, and the rod  58  formed in an annular shape is connected to the other end thereof. The rod  58  is made up from a tubular body in which the feed screw  54  can be accommodated, and is provided in a manner so that the other end thereof is exposed to the exterior with respect to a lower end portion of the second bore portion  64 , the other end being covered and closed by a socket  78 . 
     The end block  60  is formed in an L-shaped cross section and is disposed on the exterior of the second bore portion  64 . A short end portion  84  thereof is connected to the other end portion of the rod  58  by the socket  78  and a fixing bolt  82  substantially perpendicular to the rod  58 , and a side portion  86  thereof extending in a substantially perpendicular manner from one end of the end portion  84  extends in the vertical direction (the direction of arrows C 1  and C 2 ) laterally of the second bore portion  64 . 
     Further, a guide block  88  is provided on the side portion  86  on a side surface thereof facing toward the second bore portion  64 , and the guide block  88  engages with a concave guide rail  90  formed on the side wall of the second bore portion  64 . Consequently, the end block  60  which includes the side portion  86  is movably guided along the height direction (in the direction of arrows C 1  and C 2 ) of the second bore portion  64 . 
     Furthermore, on the side portion  86 , a connecting block (connecting member)  92  that constitutes a later-described driving force transmission mechanism  18  is connected by two bolts  94  to a side surface opposite to the side surface on which the guide block  88  is provided. 
     In addition, when the drive shaft  95  is rotated under an energizing action of the motor  52 , the rotational drive force thereof is transmitted to the feed screw  54  via the drive pulley  70 , the timing belt  74 , and the driven pulley  72 , and the feed screw  54  is rotated in a state of being supported by the bearings  68 . Consequently, the slider  76 , which is screwed-engaged by rotation with the feed screw  54 , moves forward and rearward in the axial direction (the direction of arrows C 1  and C 2 ) along the second bore portion  64  together with the rod  58 , and the end block  60  moves in the height direction along the guide rail  90 . 
     As shown in  FIGS. 1, 3, and 5 to 8 , the movable fingers  16   a  to  16   d  are formed, for example, with rectangular shapes in cross section, which are substantially the same shape as the fixed finger  32 , and are arranged so that elongated directions thereof are in the height direction (the direction of arrows C 1  and C 2 ). The movable fingers  16   a  to  16   d  each include, at both ends in the height direction, pairs of flange portions  96  (see  FIGS. 3 and 8 ) protruding in the height direction. 
     In addition, the movable fingers  16   a  to  16   d  are accommodated in the finger accommodating section  24  of the body  12 , and the flange portions  96  thereof are arranged so as to be located in the vertical direction (the direction of arrows C 1  and C 2 ), and inserted and placed in engagement, respectively, with the engagement grooves  30 . Consequently, the movable fingers  16   a  to  16   d  are retained movably in the longitudinal direction (the direction of arrows A 1  and A 2 ) along the finger accommodating section  24  of the body  12 . 
     Further, on the body  12 , two movable fingers  16   a  and  16   b  from among the four movable fingers  16   a  to  16   d  are arranged on one side in the longitudinal direction (the direction of the arrow A 1 ) with respect to the fixed finger  32 , whereas the remaining two movable fingers  16   c  and  16   d  are arranged on the other side in the longitudinal direction (the direction of the arrow A 2 ) with respect to the fixed finger  32 . More specifically, the four movable fingers  16   a  to  16   d  are arranged so as to have the same number on one side in the longitudinal direction (the direction of the arrow A 1 ) and on the other side in the longitudinal direction (the direction of the arrow A 2 ) with the fixed finger  32  being sandwiched therebetween. 
     Furthermore, in a state of being accommodated in the finger accommodating section  24 , the front sides of the movable fingers  16   a  to  16   d  protrude slightly more outward (in the direction of the arrow B 2 ) than the first end surfaces  28  of the body  12 , and second mounting surfaces  98  substantially in parallel with the first end surfaces  28  are provided on the protruding portions thereof. The second mounting surfaces  98  are formed so as to lie flush with the first mounting surface  34  of the fixed finger  32 , and for example, in the same manner as the fixed finger  32 , suction units P for attracting workpieces are attached thereto via mounting holes  98   a.    
     Further still, pin holes  100  are formed in the centers of the rear surfaces of the movable fingers  16   a  to  16   d , and the finger pins  110  of the driving force transmission mechanism  18 , which will be described later, are press-fitted and fixed in the pin holes  100 , respectively. On the other hand, as shown in  FIGS. 3 and 5 , pairs of spring holes  104  into which springs (elastic member)  102  are inserted are formed respectively at positions above and below the pin holes  100  (in the direction of arrows C 1  and C 2 ), in opposing side surfaces of the adjacent movable fingers  16   a  and  16   b  and of the movable fingers  16   c  and  16   d.    
     The spring holes  104  are formed respectively at a predetermined depth along the direction of movement (the direction of arrows A 1  and A 2 ) of the movable fingers  16   a  to  16   d , in the side surface of the movable finger  16   a  ( 16   d ) and the side surface of the movable finger  16   b  ( 16   c ) that lie adjacent to each other. In addition, the springs  102  are disposed between the spring holes  104  of the movable finger  16   a  ( 16   d ) and the spring holes  104  of the movable finger  16   b  ( 16   c ). More specifically, the springs  102  are disposed along the direction of movement of the movable fingers  16   a  to  16   d , and namely, along the longitudinal direction (the direction of arrows A 1  and A 2 ) of the body  12 . 
     The springs  102  are made up, for example, from coil springs, an elastic force thereof is applied in a direction in which two adjacent movable fingers  16   a  ( 16   d ) and  16   b  ( 16   c ) are separated from each other, and by such an elastic force, rattling is prevented from occurring between the adjacent movable fingers  16   a  and  16   b  ( 16   c  and  16   d ), and the movable fingers are maintained in a substantially parallel state at all times. 
     As shown in  FIGS. 2 to 8 , the driving force transmission mechanism  18  is equipped with the connecting block  92 , which is connected to the end block  60  constituting the drive unit  14  and includes a connecting bolt (connecting member)  106 , a cam plate  108  accommodated in the accommodation chamber  26  of the body  12  and connected to the connecting bolt  106 , and the finger pins  110  which are inserted through first to fourth cam grooves  122 ,  124 ,  126 , and  128  of the cam plate  108  and are connected to the movable fingers  16   a  to  16   d.    
     The connecting block  92  is made up, for example, from a block body having a rectangular cross section, is connected to the side portion  86  of the end block  60 , and is disposed so as to protrude from the side portion  86  toward the side (in the direction of the arrow A 1 ) opposite to the housing  50  of the drive unit  14 . In addition, the connecting bolt  106  is connected to the center of the connecting block  92  in the height direction, so as to protrude toward the side of the body  12  (in the direction of the arrow B 2 ). 
     Further, the connecting block  92  is positioned so as to face toward the hole  46  of the cover member  22 , in a state with the drive unit  14  being fixed to the rear surface of the body  12 , and the connecting bolt  106  is inserted through the hole  46  and enters inside the accommodation chamber  26  (see  FIG. 6 ). 
     As shown in  FIGS. 3 to 8 , the cam plate  108  is made of an elongate plate material extending along the longitudinal direction of the body  12  (in the direction of arrows A 1  and A 2 ), and is formed in a shape having substantially the same dimension as the longitudinal dimension of the accommodation chamber  26 , and roughly half of the height dimension of the accommodation chamber  26 . In addition, the cam plate  108  is accommodated in the accommodation chamber  26  so as to be capable of moving in the vertical direction (in the direction of arrows C 1  and C 2 ), and wear rings  112  are provided respectively on side portions of the cam plate  108 , such that when the cam plate  108  moves, it is guided in the vertical direction while the wear rings  112  are in contact with inner walls of the accommodation chamber  26 . 
     In the center of the cam plate  108 , the connecting bolt  106  is inserted from the rear side through a bolt hole  114  that penetrates in the thickness direction, and a nut  116  (see  FIGS. 3 and 6 ) is screw-engaged on the distal end thereof, whereby the cam plate  108  is connected to the connecting bolt  106 . 
     Further, as shown in  FIG. 4 , a pair of recesses  118  into which the convex portions  38  of the body  12  can be inserted are formed at the upper end of the cam plate  108  so as to be recessed downward (in the direction of the arrow C 2 ), and notched portions  120  that are notched diagonally are formed on lower ends of both ends thereof in the longitudinal direction. 
     Furthermore, the cam plate  108  is provided with four first to fourth cam grooves  122 ,  124 ,  126 , and  128 , which extend radially from the vicinity of the lower end toward the upper end side thereof. Two first and second cam grooves  122  and  124  are formed on one side in the longitudinal direction (in the direction of the arrow A 1 ) with the hole  46  at the center in the longitudinal direction being sandwiched therebetween, and two third and fourth cam grooves  126  and  128  are formed on the other side in the longitudinal direction (in the direction of the arrow A 2 ) with the hole  46  being sandwiched therebetween. 
     Further, the first and third cam grooves  122  and  126  on both end sides of the cam plate  108  in the longitudinal direction are formed so as to be inclined respectively at a first angle of inclination θ 1  with respect to a virtual line L passing through the center of the hole  46  in the vertical direction (the direction of arrows C 1  and C 2 ), and are formed so as to have a symmetrical shape with respect to the virtual line L. In addition, the upper ends of the first and third cam grooves  122  and  126  extend to the vicinity of the upper end of both ends of the cam plate  108  in the longitudinal direction. 
     On the other hand, the second and fourth cam grooves  124  and  128  are formed so as to be inclined respectively at a second angle of inclination θ 2 , which is smaller than the first angle of inclination θ 1 , with respect to the virtual line L (θ 2 &lt;θ 1 ), and are formed so as to have a symmetrical shape with respect to the virtual line L. In addition, the upper ends of the second and fourth cam grooves  124  and  128  extend to the vicinity of inner sides of the recesses  118  in the longitudinal direction. 
     More specifically, the first and second cam grooves  122  and  124  and the third and fourth cam grooves  126  and  128  are formed so as to have a symmetrical shape with respect to the center of the cam plate  108  in the longitudinal direction, and the first and third cam grooves  122  and  126  are formed to be longer than the second and fourth cam grooves  124  and  128 . 
     By being fixed in the pin holes  100  of the movable fingers  16   a  to  16   d , the finger pins  110  protrude toward the rear side (in the direction of the arrow B 1 ) (see  FIG. 7 ), are inserted respectively through the guide holes  44  of the body  12 , and are also inserted respectively through the first to fourth cam grooves  122 ,  124 ,  126 , and  128  in the cam plate  108 . Consequently, the finger pins  110  can be moved only in the longitudinal direction (the direction of arrows A 1  and A 2 ) of the body  12  by the guide holes  44 . 
     The variable pitch device  10  according to the first embodiment of the present invention is constructed basically as described above. Next, operations and advantages thereof will be described. The closed state in which the four movable fingers  16   a  to  16   d  shown in  FIGS. 1 and 5  are moved toward the side of the fixed finger  32 , which is in the center of the body  12  in the longitudinal direction, and approach one another will be described as an initial state. 
     In such an initial state, the end portion  84  is placed in close proximity to the other end of the second bore portion  64  (see  FIG. 2 ) by the end block  60  being moved upward (in the direction of the arrow C 1 ) under the driving action of the drive unit  14 , and as shown in  FIGS. 4 and 6 , the cam plate  108  is positioned upwardly (in the direction of the arrow C 1 ) inside the accommodation chamber  26 , and the finger pins  110  are positioned at lower ends of the first to fourth cam grooves  122 ,  124 ,  126 , and  128 . 
     Therefore, as shown in  FIG. 4 , the respective finger pins  110  are gathered together and approach the center of the body  12  in the longitudinal direction, and a state is brought about in which the movable fingers  16   a  to  16   d  to which the respective finger pins  110  are connected are gathered together toward the side of the fixed finger  32  in the center in the longitudinal direction, and are arranged in close proximity to each other at an interval separation D 1  (see  FIG. 5 ). 
     In the aforementioned initial state, by outputting a control signal from a non-illustrated controller to the motor  52  of the drive unit  14 , the drive shaft  95  of the motor  52  is rotated, the rotational driving force is transmitted to the drive pulley  70 , the timing belt  74 , and the driven pulley  72 , and the feed screw  54  is rotated in a state of being supported by the bearings  68 . 
     The slider  76  is lowered accompanying rotation of the feed screw  54 , and the rod  58  is lowered together with the slider  76 , whereby the end portion  84  of the end block  60  moves in a direction to separate away from the housing  50  (in the direction of the arrow C 2 ). In addition, the connecting block  92  is lowered together with the end block  60 , whereby the cam plate  108  connected by the connecting bolt  106  is lowered in the accommodation chamber  26  under a guiding action of the wear rings  112 . 
     As shown in  FIGS. 11 and 12 , accompanying lowering of the cam plate  108 , the respective finger pins  110  which are inserted into the guide holes  44  move respectively toward both end sides in the longitudinal direction (the direction of arrows A 1  and A 2 ), and separate away from each other in the longitudinal direction by way of the first to fourth cam grooves  122 ,  124 ,  126 , and  128 , respectively. 
     In greater detail, with respect to the finger pins  110 , by the first to fourth cam grooves  122 ,  124 ,  126 , and  128  moving from the lower end to the upper end, the respective finger pins  110  that are inserted through the first and second cam grooves  122  and  124  move along the guide hole  44  to one side in the longitudinal direction (in the direction of the arrow A 1 ) with respect to the fixed finger  32 . At this time, the finger pin  110  inserted through the first cam groove  122  further moves to one side in the longitudinal direction (in the direction of the arrow A 1 ) with respect to the finger pin  110  that is inserted through the second cam groove  124 . 
     On the other hand, the respective finger pins  110  that are inserted through the third and fourth cam grooves  126  and  128  move along the guide hole  44  to the other side in the longitudinal direction (in the direction of the arrow A 2 ) with respect to the fixed finger  32 . The finger pin  110  inserted through the third cam groove  126  further moves to the other side in the longitudinal direction (in the direction of the arrow A 2 ) with respect to the finger pin  110  that is inserted through the fourth cam groove  128 . 
     At this time, since the first and second cam grooves  122  and  124  and the third and fourth cam grooves  126  and  128  are formed so as to have a symmetrical shape with respect to the direction of movement of the cam plate  108  (in the direction of arrows C 1  and C 2 ), the movement speed and the movement distance of the respective finger pins  110  to both end sides in the longitudinal direction (the direction of arrows A 1  and A 2 ) are equivalent to each other, respectively. 
     In addition, accompanying movement of the finger pins  110 , in a similar manner, the movable fingers  16   a  to  16   d  connected to the finger pins  110  move toward both end sides in the longitudinal direction so as to separate away from the fixed finger  32 , while maintaining a state of being evenly spaced from each other in the finger accommodating section  24 . 
     Finally, as shown in  FIGS. 11, 12, and 14 , the cam plate  108  moves to the lower end in the accommodation chamber  26  under the driving action of the drive unit  14 , and the notched portions  120  thereof are placed in positions facing toward the respective corner portions  40 . Consequently, as shown in  FIGS. 10, 12, and 13 , in the longitudinal direction of the body  12 , the movable fingers  16   a  to  16   d  and the fixed finger  32  are arranged at an equal interval separation D 2  in the open state. 
     On the other hand, in the case that the aforementioned movable fingers  16   a  to  16   d  shown in  FIG. 10  are restored from the open state to the closed state, the motor  52  of the drive unit  14  is rotated in an opposite direction by a control signal from the non-illustrated controller, whereby the feed screw  54  is rotated in the opposite direction via the drive pulley  70  and the driven pulley  72 , and the rod  58  is moved so as to be drawn into the second bore portion  64 . Consequently, the end block  60  and the connecting block  92  move upward (in the direction of the arrow C 1 ) along the housing  50 , and along with such movement, the cam plate  108  moves upward inside the accommodation chamber  26 . 
     In addition, accompanying rising of the cam plate  108 , the respective finger pins  110  inserted into the guide holes  44  move respectively toward the side of the fixed finger  32  by way of the first to fourth cam grooves  122 ,  124 ,  126 , and  128 . Then, as shown in  FIG. 5 , the movable fingers  16   a  to  16   d  which are connected to the finger pins  110  approach one another, and are placed in the closed state with the interval separation D 1  therebetween. More specifically, in the above-described variable pitch device  10 , the direction of movement of the rod  58  in the drive unit  14  (the output direction, the direction of arrows C 1  and C 2 ) and the direction of movement of the movable fingers  16   a  to  16   d  (the direction of arrows A 1  and A 2 ) are perpendicular to each other. 
     Next, a description will be given concerning a case in which the above-described variable pitch device  10  is attached to the distal end of an arm in a non-illustrated transport device, and a plurality of workpieces are transported by respective suction units P that are attached to the fixed finger  32  and the movable fingers  16   a  to  16   d.    
     At first, in the closed state, which is the initial state of the variable pitch device  10  shown in  FIGS. 1 and 7 , five workpieces that are placed on the supply source are attracted and gripped by the suction units P which are provided on the fixed finger  32  and the movable fingers  16   a  to  16   d . At this time, the interval separation between the respective workpieces corresponds to the interval separation D 1  of the fixed finger  32  and the movable fingers  16   a  to  16   d  in the closed state. 
     Next, during transport of the workpieces from the supply source to the supply destination for the workpieces, under the driving action of the drive unit  14 , the four movable fingers  16   a  to  16   d  are moved toward both ends of the body  12  in the longitudinal direction with respect to the fixed finger  32 , whereby the interval separation is increased in a manner so that the five workpieces which are gripped by the suction units P are separated from each other. In addition, by movement of the cam plate  108  of the variable pitch device  10  to the lower end, as shown in  FIGS. 10, 12, and 13 , the fixed finger  32  and the four movable fingers  16   a  to  16   d  are placed in the open state of being separated at the maximum interval separation D 2 , and the five workpieces are also placed in a state of being separated at the interval separation D 2 . 
     After the five workpieces, which are separated from each other at the maximum interval separation by operation of the variable pitch device  10 , have been transported to the supply destination by the transport device, the state of being attracted by the suction units P is released, whereby the five workpieces are supplied to the supply destination at an interval separation that differs from that at the supply source. 
     As described above, in the first embodiment, the cam plate  108  which is capable of moving in the vertical direction (in the direction of arrows C 1  and C 2 ) under the driving action of the drive unit  14  is provided in the interior of the accommodation chamber  26  in the body  12 , and the first to fourth cam grooves  122 ,  124 ,  126 , and  128  that are inclined at predetermined angles with respect to the direction of movement thereof (in the vertical direction) are included in the cam plate  108 . Further, the four finger pins  110 , which are inserted through the guide holes  44  that extend in the longitudinal direction (the direction of arrows A 1  and A 2 ) of the body  12 , are inserted respectively through the first to fourth cam grooves  122 ,  124 ,  126 , and  128 . In addition, the finger pins  110  are connected to the four movable fingers  16   a  to  16   d  which are disposed so as to be capable of moving in the longitudinal direction along the finger accommodating section  24  of the body  12 . 
     As a result, in the variable pitch device  10 , with a simple configuration in which the cam plate  108  and the finger pins  110  that transmit the driving force from the drive unit  14  to the plurality of movable fingers  16   a  to  16   d  are provided between the movable fingers  16   a  to  16   d  and the drive unit  14 , it becomes possible to make the size of the device smaller in the thickness direction (the direction of arrows B 1  and B 2 ), and to reduce manufacturing costs, in comparison with a conventional variable pitch device in which the driving force of the motor is transmitted to slide blocks via a plate cam and two levers. 
     Further, between each two of the movable fingers  16   a  to  16   d  that are adjacent to each other, the springs  102 , which bias the adjacent movable fingers  16   a  to  16   d  in directions away from each other (in the directions of arrows A 1  and A 2 ), are provided. Therefore, rattling is prevented from occurring between each two of the movable fingers  16   a  to  16   d  that are adjacent to each other, and the adjacent movable fingers  16   a  and  16   b  ( 16   c  and  16   d ) are suitably maintained in a substantially parallel state at all times. 
     Furthermore, since the wear rings  112 , which can slidably contact the inner walls of the accommodation chamber  26 , are provided on the side portions of the cam plate  108 , the cam plate  108  is prevented from coming into direct contact with the body  12 , and in addition, the cam plate  108  is suitably guided when moving in the vertical direction (in the direction of arrows C 1  and C 2 ) inside the accommodation chamber  26 . 
     Next, a variable pitch device  150  according to a second embodiment is shown in  FIGS. 15 to 21 . The same reference numerals are used to indicate the same constituent elements as those of the above-described variable pitch device  10  according to the first embodiment, and detailed description of such features is omitted. 
     The variable pitch device  150  according to the second embodiment differs from the variable pitch device  10  according to the first embodiment, in that it comprises a pair of guide rods (guide members)  156   a  and  156   b  for guiding a plurality of movable fingers  152   a  to  152   d  along the longitudinal direction (the direction of arrows A 1  and A 2 ) of a body  154 , and a pair of spring rods  160   a  and  160   b  for guiding springs (elastic members)  158 . 
     As shown in  FIGS. 15 to 17 , the variable pitch device  150  is equipped with end walls  164   a  and  164   b  provided respectively on both ends, in the longitudinal direction, of a main body portion  162  constituting the body  154 , and the pair of guide rods  156   a  and  156   b  and the spring rods  160   a  and  160   b  are disposed, respectively, substantially in parallel with each other in the finger accommodating section  24 . 
     The guide rods  156   a  and  156   b  are disposed on upper and lower sides in the finger accommodating section  24 , and are disposed along the longitudinal direction (the direction of arrows A 1  and A 2 ) of the body  154 , one end thereof being retained by the end wall  164   a , and the other end thereof being retained by the end wall  164   b.    
     Further, the guide rods  156   a  and  156   b  are inserted through first rod grooves  168 , which are recessed with respect to the first mounting surface  34  of a fixed finger  166 , and are inserted through first rod holes  170 , which are formed in the plurality of movable fingers  152   a  to  152   d . The first rod holes  170  are formed to penetrate along the direction of movement of the movable fingers  152   a  to  152   d , and more specifically, along the longitudinal direction (the direction of arrows A 1  and A 2 ) of the body  154 , and in the vicinity of the upper ends and the lower ends, respectively, of the movable fingers  152   a  to  152   d.    
     In addition, when the plurality of movable fingers  152   a  to  152   d  move in the finger accommodating section  24  of the body  154 , they are guided highly accurately in the longitudinal direction (the direction of arrows A 1  and A 2 ) along the pair of guide rods  156   a  and  156   b  that are inserted through the first rod holes  170 . 
     The spring rods  160   a  and  160   b  are disposed in the finger accommodating section  24  closer to a central side in the height direction than the guide rods  156   a  and  156   b , and are disposed along the longitudinal direction (the direction of arrows A 1  and A 2 ) of the body  154 , one end thereof being retained by the end wall  164   a , and the other end thereof being retained by the end wall  164   b.    
     Further, the spring rods  160   a  and  160   b  are inserted through second rod grooves  172  of the fixed finger  166 , which are recessed with respect to the first mounting surface  34 , and are inserted through second rod holes  174 , which are formed in the plurality of movable fingers  152   a  to  152   d.    
     The second rod holes  174  are formed to penetrate along the direction of movement of the movable fingers  152   a  to  152   d , and more specifically, along the longitudinal direction (the direction of arrows A 1  and A 2 ) of the body  154 , at positions closer to the side of the pin holes  100  than the first rod holes  170 , and at symmetrical positions with respect to the heightwise center of the movable fingers  152   a  to  152   d  having the pin holes  100 . Further, the second rod holes  174  are formed coaxially with the spring holes  104  into which the springs  158  are inserted. 
     In addition, between the two adjacent movable fingers  152   a  and  152   b  ( 152   c  and  152   d ), the springs  158  are inserted onto outer circumferential sides of the spring rods  160   a  and  160   b , and both ends of the springs  158  are inserted respectively into the spring holes  104  (see  FIG. 16 ). More specifically, the spring rods  160   a  and  160   b  are used as a guide unit that retains, in the longitudinal direction of the body  154 , the springs  158  interposed between the movable fingers  152   a  and  152   b  ( 152   c  and  152   d ). 
     The variable pitch device  150  according to the second embodiment of the present invention is constructed basically as described above. Next, operations and advantages thereof will be described. Moreover, concerning operations that are the same as those of the variable pitch device  10  according to the first embodiment, detailed description of such features will be omitted. 
     First, in the closed state shown in  FIGS. 20 and 21 , the cam plate  108  is positioned upwardly (in the direction of the arrow C 1 ) inside the body  154 , and against the elastic force of the springs  158  provided between the movable fingers  152   a  to  152   d , the four movable fingers  152   a  to  152   d  are in a state of being moved and placed in close proximity to the side of the fixed finger  166 , which is located in the center in the longitudinal direction of the body  154 . Moreover, the aforementioned springs  158  are accommodated respectively inside the spring holes  104  in the movable fingers  152   a  to  152   d.    
     Next, the cam plate  108  is lowered inside the body  154  under a driving action of the drive unit  14 , whereby the finger pins  110  start to move toward both end sides (in the directions of arrows A 1  and A 2 ) in the longitudinal direction of the body  154  by way of the first to fourth cam grooves  122 ,  124 ,  126 , and  128 , and accordingly, as shown in  FIGS. 15 and 17 , the respective movable fingers  152   a  to  152   d  move toward both end sides in the longitudinal direction so as to be separated from the fixed finger  166 . 
     At this time, the movable fingers  152   a  to  152   d  are guided smoothly and with high accuracy along the longitudinal direction of the body  154  by the pair of guide rods  156   a  and  156   b . Further, by the springs  158  provided between the adjacent movable fingers  152   a  and  152   b  ( 152   c  and  152   d ), rattling is prevented from occurring between the movable fingers  152   a  and  152   b  ( 152   c  and  152   d ), and since the springs  158  are arranged symmetrically with respect to the heightwise center of the movable fingers  152   a  to  152   d , the adjacent movable fingers  152   a  to  152   d  are maintained in a substantially parallel state at all times. 
     In addition, as shown in  FIG. 17 , the cam plate  108  moves to the lower end inside the accommodation chamber  26  under the driving action of the drive unit  14 , whereby in the longitudinal direction of the body  154 , the respective movable fingers  152   a  to  152   d  and the fixed finger  166  are arranged respectively at an equal interval separation D 2  in the open state. 
     As described above, in the second embodiment, the cam plate  108  which is capable of moving in the vertical direction (in the direction of arrows C 1  and C 2 ) under the driving action of the drive unit  14  is provided in the interior of the body  154 , and the first to fourth cam grooves  122 ,  124 ,  126 , and  128  that are inclined at predetermined angles with respect to the direction of movement thereof (in the vertical direction) are included in the cam plate  108 . Further, the four finger pins  110 , which are inserted through the guide holes  44  that extend in the longitudinal direction (the direction of arrows A 1  and A 2 ) of the body  154 , are inserted respectively through the first to fourth cam grooves  122 ,  124 ,  126 , and  128 . In addition, the finger pins  110  are connected to the four movable fingers  152   a  to  152   d  which are disposed so as to be capable of moving in the longitudinal direction along the finger accommodating section  24  of the body  154 . 
     As a result, in the variable pitch device  150 , with a simple configuration in which the cam plate  108  and the finger pins  110  that transmit the driving force from the drive unit  14  to the movable fingers  152   a  to  152   d  are provided between the plurality of movable fingers  152   a  to  152   d  and the drive unit  14 , it becomes possible to make the size of the device smaller in the thickness direction (the direction of arrows B 1  and B 2 ), and to reduce manufacturing costs, in comparison with a conventional variable pitch device in which the driving force of the motor is transmitted to slide blocks via a plate cam and two levers. 
     Further, in the finger accommodating section  24  of the body  154 , the pair of guide rods  156   a  and  156   b  which extend along the longitudinal direction are provided, and the guide rods  156   a  and  156   b  are inserted through the first rod holes  170  of the movable fingers  152   a  to  152   d . Consequently, when the movable fingers  152   a  to  152   d  move along the longitudinal direction (the direction of arrows A 1  and A 2 ) of the body  154  under the driving action of the drive unit  14 , they can be guided in the longitudinal direction by the guide rods  156   a  and  156   b , whereby it becomes possible for the plurality of movable fingers  152   a  to  152   d  to be operated smoothly and with high accuracy. 
     Furthermore, in the finger accommodating section  24  of the body  154 , by providing the spring rods  160   a  and  160   b  for guiding the springs  158  along the longitudinal direction, the elastic force of the springs  158  can be applied in the longitudinal direction with respect to the movable fingers  152   a  to  152   d . Therefore, the adjacent movable fingers  152   a  to  152   d  can be maintained in parallel at all times, and the distance between the movable fingers  152   a  to  152   d  can be managed in a highly accurate manner. 
     Next, a variable pitch device  200  according to a third embodiment is shown in  FIGS. 22 to 31 . The same reference numerals are used to indicate the same constituent elements as those of the above-described variable pitch device  150  according to the second embodiment, and detailed description of such features is omitted. 
     The variable pitch device  200  according to the third embodiment differs from the variable pitch device  150  according to the second embodiment, in that a drive unit  202  is arranged substantially in parallel along the longitudinal direction (the direction of arrows A 1  and A 2 ) of a body  204 , and a sub-cam plate (conversion member)  208  connected to the drive unit  202  and constituting a driving force transmission mechanism  206  is provided. 
     As shown in  FIGS. 22 to 27 , the variable pitch device  200  includes the body  204 , the drive unit  202  mounted on a rear surface of the body  204 , a plurality of movable fingers  152   a  to  152   d  which are disposed so as to be capable of moving along the longitudinal direction (the direction of arrows A 1  and A 2 ) of the body  204 , and the driving force transmission mechanism  206  that transmits the driving force of the drive unit  202  to the movable fingers  152   a  to  152   d.    
     The body  204  is formed in an elongate shape along the longitudinal direction (the direction of arrows A 1  and A 2 ), and is equipped with the main body portion  162  that retains the movable fingers  152   a  to  152   d  in a movable manner, the cover member  22  that is mounted on a rear side (in the direction of the arrow B 1 ) of the main body portion  162 , and a box-shaped casing  210  that covers the rear side of the main body portion  162  together with the cover member  22 . 
     As shown in  FIGS. 23, 24, 26, and 27 , the drive unit  202  is made up from an electric actuator that can be driven under an energizing action, and the housing  50  is connected to the rear surface of the cover member  22  so as to extend along the longitudinal direction (the direction of arrows A 1  and A 2 ) of the body  204 . In addition, in the drive unit  202 , the rod  58  moves forward and rearward along the longitudinal direction of the body  204  under the energizing action. 
     Moreover, the main structure of the drive unit  202  is substantially the same as that of the drive unit  14  used in the variable pitch devices  10  and  150  according to the first and second embodiments, and one end side thereof on which the pulley cover  66  is provided is fixed so as to be on one side in the longitudinal direction (in the direction of the arrow A 1 ) of the body  204 . 
     Further, as shown in  FIGS. 23 and 26 , the sub-cam plate  208  that constitutes the driving force transmission mechanism  206  is movably provided on the rear side of the cover member  22 . The sub-cam plate  208  includes a base portion  212  formed in a rectangular plate-like shape, and a connecting piece  214  that is erected from the base portion  212 . In addition, the sub-cam plate  208  is disposed in a manner so that the base portion  212  is in contact with the rear surface of the cover member  22 , and the upper end and the lower end thereof are retained movably in the longitudinal direction (the direction of arrows A 1  and A 2 ) by a pair of guide pieces  216   a  and  216   b  which are provided in the vicinity of the upper end and the lower end of the cover member  22 . 
     A sub-cam groove (second cam groove)  218  is formed in the base portion  212  between the upper end and the lower end which are retained by the pair of guide pieces  216   a  and  216   b . The sub-cam groove  218  is formed in an inclined manner at a predetermined angle with respect to the direction of movement (the direction of arrows A 1  and A 2 ) of the sub-cam plate  208  such that, with respect to the central lower end on which the connecting piece  214  is provided, the upper end thereof is formed on the side of the drive unit  202  (in the direction of the arrow A 1 ), and the lower end thereof is formed on the opposite side (in the direction of the arrow A 2 ) from the drive unit  202 . In addition, the connecting bolt  106  which is connected to the cam plate  108  is movably inserted through the sub-cam groove  218 . 
     The connecting piece  214  protrudes in a direction away from the cover member  22  (in the direction of the arrow B 1  in  FIGS. 23 and 28 ) substantially perpendicular to the base portion  212 , and the other end of the rod  58  in the drive unit  202  is connected thereto via the socket  78  and the fixing bolt  82  (see  FIG. 27 ). 
     In addition, by the rod  58  moving forward and rearward in the axial direction under a driving action of the drive unit  202 , the sub-cam plate  208  moves along the longitudinal direction (in the direction of arrows A 1  and A 2 ) of the body  204  in a state of being retained by the pair of guide pieces  216   a  and  216   b.    
     Further, the drive unit  202  and the sub-cam plate  208  described above are covered by the casing  210  which is mounted on the rear side of the main body portion  162  (see  FIG. 23 ). 
     The variable pitch device  200  according to the third embodiment of the present invention is constructed basically as described above. Next, operations and advantages thereof will be described. 
     First, in the closed state shown in  FIGS. 22 and 25 , in the drive unit  202 , the other end of the rod  58  is pushed out to the other side in the longitudinal direction (in the direction of the arrow A 2 ), and along therewith, the sub-cam plate  208  is moved to the other side in the longitudinal direction as shown in  FIGS. 23 and 26 , and the connecting bolt  106  is positioned at the upper end in the sub-cam groove  218  (see  FIG. 28 ). Therefore, the cam plate  108  connected to the connecting bolt  106  is positioned upwardly (in the direction of the arrow C 1 ) inside the body  204 , and against the elastic force of the springs  158 , the four movable fingers  152   a  to  152   d  are in a state of being moved and placed in close proximity to the side of the fixed finger  166 , which is located in the center in the longitudinal direction of the body  204 . 
     In the aforementioned initial state, by inputting a control signal from a non-illustrated controller to the drive unit  202 , the rod  58  moves in the axial direction (in the direction of the arrow A 1 ) and is drawn into the housing  50  under a rotating action of the motor  52 . In addition, accompanying movement of the rod  58 , the sub-cam plate  208  moves to one side in the longitudinal direction (in the direction of the arrow A 1 ) of the body  204  under a guiding action of the guide pieces  216   a  and  216   b.    
     By movement of the sub-cam plate  208 , the connecting bolt  106 , which is inserted through the sub-cam groove  218 , is lowered, and the cam plate  108  connected thereto is lowered inside the accommodation chamber  26 . In addition, as shown in  FIGS. 29 and 30 , accompanying lowering of the cam plate  108 , the respective finger pins  110  which are inserted into the guide holes  44  move respectively toward both end sides in the longitudinal direction (the direction of arrows A 1  and A 2 ), and separate away from each other in the longitudinal direction by way of the first to fourth cam grooves  122 ,  124 ,  126 , and  128 , respectively. 
     Accompanying movement of the finger pins  110 , in a similar manner, the movable fingers  152   a  to  152   d  connected to the finger pins  110  move toward both end sides in the longitudinal direction so as to separate away from the fixed finger  166  in the finger accommodating section  24  of the body  204 . 
     Finally, as shown in  FIGS. 29 to 31 , the cam plate  108  moves to the lower end inside the accommodation chamber  26  under the driving action of the drive unit  202 , whereby in the longitudinal direction of the body  204 , the respective movable fingers  152   a  to  152   d  and the fixed finger  166  are arranged at an equal interval separation D 2  (see  FIG. 39 ) in the open state. Moreover, the above-described variable pitch device  200  is configured in a manner so that the direction of movement of the rod  58  in the drive unit  202  (the output direction, the direction of arrows A 1  and A 2 ) and the direction of movement of the movable fingers  152   a  to  152   d  (the direction of arrows A 1  and A 2 ) are in parallel with each other. 
     More specifically, the aforementioned sub-cam plate  208  functions as an output conversion unit for converting the output along the longitudinal direction from the rod  58  of the drive unit  202  into the vertical direction (the direction of arrows C 1  and C 2 ), and transmitting the converted output to the cam plate  108 . 
     As described above, in the third embodiment, the cam plate  108  which is capable of moving in the vertical direction (in the direction of arrows C 1  and C 2 ) via the sub-cam plate  208  under the driving action of the drive unit  202  is provided, and the first to fourth cam grooves  122 ,  124 ,  126 , and  128  that are inclined at predetermined angles with respect to the direction of movement thereof (in the vertical direction) are included in the cam plate  108 . Further, the four finger pins  110 , which are inserted through the guide holes  44  that extend in the longitudinal direction (the direction of arrows A 1  and A 2 ) of the body  204 , are inserted respectively through the first to fourth cam grooves  122 ,  124 ,  126 , and  128 . In addition, the finger pins  110  are connected to the four movable fingers  152   a  to  152   d  which are disposed so as to be capable of moving in the longitudinal direction along the finger accommodating section  24  of the body  204 . 
     As a result, in the variable pitch device  200 , with a simple configuration in which the cam plate  108 , the sub-cam plate  208 , and the finger pins  110  that transmit the driving force from the drive unit  202  to the movable fingers  152   a  to  152   d  are provided between the plurality of movable fingers  152   a  to  152   d  and the drive unit  202 , it becomes possible to make the device smaller in size and to reduce manufacturing costs by eliminating the need for a swinging member, in comparison with a conventional variable pitch device provided with two levers that swing with respect to a base plate. 
     Further, by arranging the drive unit  202 , which is made up from an electric actuator, along the longitudinal direction (the direction of arrows A 1  and A 2 ) of the body  204 , the drive unit  202  does not protrude in the height direction (the direction of arrows C 1  and C 2 ) from the body  204 . Thus, it becomes possible to reduce the height of the variable pitch device  200 . Therefore, the variable pitch device  200  is suitable for a case in which there is a restriction in the height direction, for example, when the variable pitch device  200  is attached to a non-illustrated transport device. 
     Next, a variable pitch device  250  according to a fourth embodiment is shown in  FIGS. 32 to 41 . The same reference numerals are used to indicate the same constituent elements as those of the above-described variable pitch device  200  according to the third embodiment, and detailed description of such features is omitted. 
     The variable pitch device  250  according to the fourth embodiment differs from the variable pitch device  200  according to the third embodiment, in that a fluid pressure cylinder is used as a drive unit  254  instead of an electric actuator. 
     As shown in  FIGS. 32 to 41 , in the variable pitch device  250 , the drive unit  254  is mounted on the rear surface of the cover member  22  that constitutes a body  252 , along the longitudinal direction (the direction of arrows A 1  and A 2 ) of the body  252 , and the drive unit  254  is made up, for example, from a fluid pressure cylinder in which a piston  256  and a piston rod (output shaft)  258  move forward and rearward in the axial direction under a fluid supplying action. 
     As shown in  FIGS. 36 and 38 , the drive unit  254  comprises a cylindrical cylinder tube  260  fixed to the cover member  22 , the piston  256  displaceably provided along a cylinder chamber  262  of the cylinder tube  260 , and a piston rod  258  extending in the axial direction (the direction of arrows A 1  and A 2 ) from the center of one end of the piston  256 , and a pair of ports  264   a  and  264   b  formed in the cylinder tube  260  communicate with the cylinder chamber  262  which is divided by the piston  256 . In addition, the drive unit  254  is fixed in a manner so that the axial direction of the piston  256  and the piston rod  258  lie along the longitudinal direction (the direction of arrows A 1  and A 2 ) of the body  252 . 
     Further, a rod cover  266  is attached to an open end of the cylinder tube  260  and closes the cylinder tube  260 , and a distal end of the piston rod  258  which is inserted through the center of the rod cover  266  is exposed to the exterior, and connected to a connecting piece  270  of a sub-cam plate (conversion member)  268  via a bolt  272 . The connecting piece  270  is disposed in the vicinity of an end portion of the sub-cam plate  268  on the side of the drive unit  254  (in the direction of the arrow A 2 ) (see  FIG. 36 ). 
     In addition, by the fluid being supplied to the cylinder chamber  262  of the cylinder tube  260  through either one of the ports  264   a  and  264   b , the piston  256  and the piston rod  258  move in the axial direction (the direction of arrows A 1  and A 2 ), and the sub-cam plate  268  moves integrally along the longitudinal direction of the body  252 . 
     The variable pitch device  250  according to the fourth embodiment of the present invention is constructed basically as described above. Next, operations and advantages thereof will be described. 
     First, in the closed state shown in  FIGS. 32 and 35 to 37 , in the drive unit  254 , the piston rod  258  is drawn into the interior of the cylinder tube  260 , and along therewith, the sub-cam plate  268  is moved to the other side in the longitudinal direction (in the direction of the arrow A 2 ), and the connecting bolt  106  is positioned at the upper end in the sub-cam groove  218  (see  FIG. 36 ). 
     Therefore, the cam plate  108  connected to the connecting bolt  106  is positioned upwardly (in the direction of the arrow C 1 ) inside the body  252 , and as shown in  FIG. 35 , against the elastic force of the springs  158 , the four movable fingers  152   a  to  152   d  are in a state of being moved and placed in close proximity to the side of the fixed finger  166 , which is located in the center in the longitudinal direction of the body  252 . 
     In the above-described initial state, by supplying a fluid from the non-illustrated fluid source to the cylinder chamber  262  through the port  264   a , the piston  256  is biased toward the side of the rod cover  266  (to one side in the longitudinal direction), and by the piston rod  258  moving integrally therewith, the sub-cam plate  268  moves to the one side in the longitudinal direction (the direction of the arrow A 1 ) of the body  252  under a guiding action of the guide pieces  216   a  and  216   b.    
     By movement of the sub-cam plate  268 , the connecting bolt  106 , which is inserted through the sub-cam groove  218 , is lowered along the hole  46 , and the cam plate  108  connected thereto is lowered inside the accommodation chamber  26 . In addition, accompanying lowering of the cam plate  108 , the respective finger pins  110  which are inserted into the guide holes  44  move respectively toward both end sides in the longitudinal direction (the direction of arrows A 1  and A 2 ), and separate away from each other in the longitudinal direction by way of the first to fourth cam grooves  122 ,  124 ,  126 , and  128 , respectively. 
     In addition, accompanying movement of the finger pins  110 , in a similar manner, the movable fingers  152   a  to  152   d  connected to the finger pins  110  move toward both end sides in the longitudinal direction (the direction of arrows A 1  and A 2 ) so as to separate away from the fixed finger  166  in the finger accommodating section  24  of the body  252 , as shown in  FIGS. 39 and 40 . 
     Finally, as shown in  FIGS. 39 and 41 , the cam plate  108  moves to the lower end inside the accommodation chamber  26  under the driving action of the drive unit  254 , whereby in the longitudinal direction of the body  252 , the respective movable fingers  152   a  to  152   d  and the fixed finger  166  are arranged at an equal interval separation D 2  (see  FIG. 29 ) in the open state. 
     On the other hand, in the case that the movable fingers  152   a  to  152   d  are restored from the aforementioned open state to the closed state, the fluid is supplied to the port  264   b , which is opposite to the port  264   a , with respect to the drive unit  254 . Consequently, the piston  256  and the piston rod  258  move toward the other side in the longitudinal direction (in the direction of the arrow A 2 ) of the body  252 , and are drawn into the interior of the cylinder tube  260 , and along therewith, the sub-cam plate  268  is moved to the other side in the longitudinal direction (in the direction of the arrow A 2 ) along the body  252 . Along therewith, the connecting bolt  106  that is inserted through the sub-cam groove  218  rises, and the cam plate  108  moves upward (in the direction of the arrow C 1 ) inside the accommodation chamber  26 . 
     In addition, accompanying rising of the cam plate  108 , the respective finger pins  110  inserted into the guide holes  44  move respectively toward the side of the fixed finger  166  by way of the first to fourth cam grooves  122 ,  124 ,  126 , and  128 , respectively, and as shown in  FIG. 35 , they approach one another and are placed in the closed state with the interval separation D 1  therebetween. More specifically, the above-described variable pitch device  250  is configured in a manner so that the direction of movement of the piston rod  258  in the drive unit  254  (the output direction, the direction of arrows A 1  and A 2 ) and the direction of movement of the movable fingers  152   a  to  152   d  (the direction of arrows A 1  and A 2 ) are in parallel with each other. 
     Moreover, the aforementioned sub-cam plate  268  functions as an output conversion unit for converting the output along the longitudinal direction from the piston rod  258  of the drive unit  254  into the vertical direction (the direction of arrows C 1  and C 2 ), and transmitting the converted output to the cam plate  108 . 
     As described above, in the fourth embodiment, the cam plate  108  which is capable of moving in the vertical direction (in the direction of arrows C 1  and C 2 ) via the sub-cam plate  268  under the driving action of the drive unit  254  is provided, and the first to fourth cam grooves  122 ,  124 ,  126 , and  128  that are inclined at predetermined angles with respect to the direction of movement thereof (in the vertical direction) are included in the cam plate  108 . Further, the four finger pins  110 , which are inserted through the guide holes  44  that extend in the longitudinal direction (the direction of arrows A 1  and A 2 ) of the body  252 , are inserted respectively through the first to fourth cam grooves  122 ,  124 ,  126 , and  128 . In addition, the finger pins  110  are connected to the four movable fingers  152   a  to  152   d  which are disposed so as to be capable of moving in the longitudinal direction along the finger accommodating section  24  of the body  252 . 
     As a result, in the variable pitch device  250 , with a simple configuration in which the cam plate  108 , the sub-cam plate  268 , and the finger pins  110  that transmit the driving force from the drive unit  254  to the movable fingers  152   a  to  152   d  are provided between the plurality of movable fingers  152   a  to  152   d  and the drive unit  254 , it becomes possible to make the device smaller in size and to reduce manufacturing costs by eliminating the need for a swinging member, in comparison with a conventional variable pitch device provided with two levers that swing with respect to a base plate. 
     Further, by arranging the drive unit  254 , which is made up from a fluid pressure cylinder, along the longitudinal direction (the direction of arrows A 1  and A 2 ) of the body  252 , since the drive unit  254  does not protrude in the height direction (the direction of arrows C 1  and C 2 ) from the body  252 . Thus, it becomes possible to reduce the height of the variable pitch device  250 . Therefore, the variable pitch device  250  is suitable for a case in which there is a restriction in the height direction, for example, when the variable pitch device  250  is attached to a non-illustrated transport device. 
     Furthermore, by using the fluid pressure cylinder as the drive unit  254 , in comparison with the variable pitch device  200  according to the third embodiment in which an electric actuator is used as the drive unit  202 , it is possible to make the size of the device smaller in the thickness direction (the direction of arrows B 1  and B 2 ). 
     Next, a description will be given concerning variable pitch devices  280 ,  300 , and  310  equipped with stopper mechanisms which are capable of adjusting the interval separation between the plurality of movable fingers  152   a  to  152   d  in the open state. The same reference numerals are used to indicate the same constituent elements as those of the above-described variable pitch device  250  according to the fourth embodiment, and detailed description of such features is omitted. 
     First, as shown in  FIGS. 42 and 43 , the variable pitch device  280  according to a first modification includes a first stopper mechanism  282  that faces toward the direction of movement (the direction of arrows A 1  and A 2 ) of the sub-cam plate  268  on the rear surface of the cover member  22 . The first stopper mechanism  282  is provided, for example, on one side in the longitudinal direction (the direction of the arrow A 1 ) of the body  252 , and includes a holder  284  fixed to the rear surface of the cover member  22 , a stopper pin (stopper member)  286  screw-engaged with the holder  284 , and a lock nut  288  that regulates forward and rearward movement of the stopper pin  286 . 
     The holder  284  is disposed substantially at a right angle with respect to the rear surface of the cover member  22 , and additionally, is disposed at a position on the axis of the piston rod  258  in the drive unit  254 . In addition, a screw hole  290 , which penetrates along the longitudinal direction (the direction of arrows A 1  and A 2 ) of the body  252 , is formed at the center of the holder  284 , and the stopper pin  286  is screw-engaged therein. 
     The stopper pin  286  is made up from a shaft body having a screw thread formed on the outer circumferential surface thereof, is screw-engaged into the screw hole  290  of the holder  284 , is provided so as to be movable forward and rearward in the axial direction (the direction of arrows A 1  and A 2 ) by being screw-rotated with respect to the holder  284 , and is formed coaxially with the piston rod  258  that constitutes the drive unit  254 . Stated otherwise, the stopper pin  286  is provided so as to be capable of approaching toward and separating away from the sub-cam plate  268 . 
     The lock nut  288  is screw-engaged with the stopper pin  286 , and is provided so as to be on one side in the longitudinal direction (in the direction of the arrow A 1 ) of the body  252  with respect to the holder  284 . Further, when the lock nut  288  comes into contact with the side surface of the holder  284 , screw-rotation of the stopper pin  286  with respect to the holder  284  is restricted. 
     On the other hand, a stopper block  292  substantially in parallel with the connecting piece  270  is formed on the sub-cam plate  268 . The stopper block  292  is substantially perpendicular to the base portion  212 , protrudes in the same direction as the connecting piece  270 , and is disposed on one side in the longitudinal direction (in the direction of the arrow A 1 ) of the base portion  212 . Further, the stopper block  292  is formed at a position forming a straight line with the connecting piece  270  in the direction of movement of the sub-cam plate  268 , and is arranged so as to face toward the distal end of the stopper pin  286  of the first stopper mechanism  282 . 
     Next, a description will be given concerning a case in which the interval separation between the plurality of movable fingers  152   a  to  152   d  in the open state is adjusted. First, in the closed state (the initial state) shown in  FIG. 42 , the stopper pin  286  of the first stopper mechanism  282  is screw-rotated, and the distal end of the stopper pin  286  is moved so as to be placed on the side of the drive unit  254  (in the direction of the arrow A 2 ) beyond the position of the sub-cam plate  268  in the open state of the movable fingers  152   a  to  152   d . In addition, in order to prevent further rotation of the stopper pin  286 , the lock nut  288  is screw-rotated and placed in contact with the holder  284 . 
     In a state in which the stopper pin  286  is positioned and fixed in the axial direction as described above, the sub-cam plate  268  moves toward the side of the first stopper mechanism  282  (in the direction of the arrow A 1 ) under the driving action of the drive unit  254 , whereby further movement thereof is restricted by the stopper block  292  coming into contact with the distal end of the stopper pin  286 . More specifically, the sub-cam plate  268  is stopped at a position that is nearer to the front side (in the direction of the arrow A 2 ) by a predetermined distance than the movement position E (see  FIG. 43 ) at the maximum interval separation in which the movable fingers  152   a  to  152   d  are fully opened. 
     Therefore, as shown in  FIG. 43 , movement of the sub-cam plate  268  to one side in the longitudinal direction (in the direction of the arrow A 1 ) is restricted, whereby the lowering operation of the cam plate  108  is stopped midway during movement thereof, and the finger pins  110  are also placed in a state of being stopped between the upper end and the lower end of the first to fourth cam grooves  122 ,  124 ,  126 , and  128  in the cam plate  108 . 
     As a result, the plurality of movable fingers  152   a  to  152   d  do not open from the closed state to the fully open state at the maximum interval separation D 2 , but are placed in the open state at an equal interval separation D 3  which is smaller than the interval separation D 2  (D 3 &lt;D 2 ). 
     In the foregoing manner, the stopper pin  286  of the first stopper mechanism  282  is moved forward and rearward in the axial direction, and the movement distance (movement position) when the sub-cam plate  268  is moved is capable of being adjusted, whereby it is possible to freely adjust the interval separation between the movable fingers  152   a  to  152   d  in the open state. 
     Further, the present invention is not limited to a case, as in the above-described first stopper mechanism  282 , in which the stopper mechanism is provided on the rear side of the body  252  and regulates the amount of movement of the sub-cam plate  268 . For example, as in the variable pitch device  300  according to a second modification shown in  FIGS. 44 and 45 , a second stopper mechanism  302  may be provided which is capable of directly regulating the movement of the movable fingers  152   a  to  152   d  along the longitudinal direction. 
     In this variable pitch device  300 , for example, a screw hole  304  that penetrates in the longitudinal direction is formed in the end wall  164   b  on the other side in the longitudinal direction of the main body portion  162  that constitutes the body  252 , a stopper pin (stopper member)  306  is screw-engaged in the screw hole  304  while being capable of moving forward and rearward, and a lock nut  308 , which is screw-engaged with the stopper pin  306 , is disposed so as to be on the outer side (in the direction of the arrow A 2 ) of the end wall  164   b.    
     The stopper pin  306  is disposed in a manner so as to protrude from the end wall  164   b  toward the side of the finger accommodating section  24  (in the direction of the arrow A 1 ) in which the movable fingers  152   a  to  152   d  are accommodated, and is provided movably along the longitudinal direction of the body  252  under a screw-rotating action thereof. 
     In accordance with such a configuration, when the plurality of movable fingers  152   a  to  152   d , which are in the closed state shown in  FIG. 44 , move toward both end sides in the longitudinal direction under the driving action of the drive unit  254 , then as shown in  FIG. 45 , further movement thereof is restricted due to the movable finger  152   c , which faces toward the stopper pin  306  of the second stopper mechanism  302 , coming into contact with the distal end of the stopper pin  306 . In addition, by the movable finger  152   c  coming into contact with the stopper pin  306 , downward movement of the cam plate  108  through which the movable finger  152   c  is inserted is also restricted, whereby movement of the three movable fingers  152   a ,  152   b , and  152   d  other than the movable finger  152   c  is also regulated and stopped at the same time. 
     As a result, the plurality of movable fingers  152   a  to  152   d  do not open from the closed state to the fully open state at the maximum interval separation D 2 , but are placed in the open state while being separated from each other by an interval separation D 4  which is smaller than the interval separation D 2  (D 4 &lt;D 2 ). 
     In the foregoing manner, by moving the stopper pin  306  of the second stopper mechanism  302  forward and rearward in the axial direction, and bringing the movable finger  152   c  into contact with the stopper pin  306 , the movement distance (movement position) when the movable fingers  152   a  to  152   d  are moved is capable of being adjusted, whereby it is possible to freely adjust the interval separation between the movable fingers  152   a  to  152   d  in the open state. 
     Further, a variable pitch device  310  according to a third modification shown in  FIGS. 46 to 48  includes a third stopper mechanism  312  that faces toward the direction of movement (the direction of the arrow A 1 ) of the sub-cam plate  268  on the rear surface of the cover member  22 , and the third stopper mechanism  312  is constituted from a cylinder device  314  that is driven under a fluid supplying action. Moreover, since the cylinder device  314  that constitutes the third stopper mechanism  312  has the same configuration as that of the drive unit  254  according to the fourth embodiment, detailed description of this feature will be omitted. 
     The cylinder device  314  constituting the third stopper mechanism  312  faces toward the stopper block  292  of the sub-cam plate  268 , and a piston rod (stopper member)  316  thereof is disposed coaxially with the piston rod  258  that constitutes the drive unit  254 . 
     Further, in the drawn-in position in which the piston rod  316  shown in  FIG. 46  has been moved to the one side in the longitudinal direction (in the direction of the arrow A 1 ) of the body  252 , the cylinder device  314  is arranged so that the distal end of the piston rod  316  does not come into contact with the sub-cam plate  268 , whereas in the pushed-out position in which the piston rod  316  shown in  FIG. 48  has been moved to the other side in the longitudinal direction (in the direction of the arrow A 2 ), the cylinder device  314  is arranged so that the distal end of the piston rod  316  is capable of contacting the sub-cam plate  268 . 
     In addition, in the case that the distance between the plurality of movable fingers  152   a  to  152   d  in the open state is to be adjusted, the fluid is supplied to a port  318   a  in the cylinder device  314  in the closed state (initial state) shown in  FIG. 46 , whereby the piston rod  316  is moved to the pushed-out position of being pushed out toward the side of the sub-cam plate  268  (in the direction of the arrow A 2 ) (see  FIG. 48 ). 
     Consequently, as shown in  FIG. 47 , when the sub-cam plate  268  is moved to the side of the cylinder device  314  (in the direction of the arrow A 1 ) under the driving action of the drive unit  254 , further movement of the sub-cam plate  268  is restricted by the distal end of the piston rod  316  coming into contact therewith. As a result, lowering of the cam plate  108  is stopped midway during movement thereof, and the finger pins  110  are also placed in a state of being stopped between the upper end and the lower end of the first to fourth cam grooves  122 ,  124 ,  126 , and  128  in the cam plate  108 . As a result, the plurality of movable fingers  152   a  to  152   d  do not open from the closed state to the fully open state at the maximum interval separation D 2 , but are placed in the open state while being separated from each other by an interval separation D 5  which is smaller than the interval separation D 2  (D 5 &lt;D 2 ). 
     Further, as shown in  FIG. 48 , by placing the cylinder device  314  in the drawn-in position under the action of supplying the fluid to a port  318   b , the sub-cam plate  268  does not contact with the distal end of the piston rod  316  when moving to the side of the cylinder device  314 . Therefore, the sub-cam plate  268  moves to a desired position along the body  252 , and along therewith, the cam plate  108  is moved to the lower end of the accommodation chamber  26 , whereby the plurality of movable fingers  152   a  to  152   d  can be placed in the fully open state of being opened at the maximum interval separation D 2 . 
     In the foregoing manner, in the variable pitch device  310  equipped with the third stopper mechanism  312 , it is possible to displace the piston rod  316  under the action of supplying the fluid to the cylinder device  314 , and to freely switch between the pushed-out position (regulated state) in which movement of the sub-cam plate  268  in the longitudinal direction can be regulated, and the drawn-in position (unregulated state) in which movement of the sub-cam plate  268  is not hindered. 
     As a result, by the supply of the fluid, the movable fingers  152   a  to  152   d  can be switched by the third stopper mechanism  312  between an open state in which the cam plate  108  is moved to the lower end and the movable fingers  152   a  to  152   d  are fully opened, and an intermediate open state between the closed state and the open state in which the cam plate  108  is stopped at an intermediate location. Consequently, when a plurality of workpieces are transported using the variable pitch device  310 , the workpieces can be supplied to a supply destination at two different intervals D 2  and D 5 . 
     The variable pitch device according to the present invention is not limited to the embodiments described above, and it goes without saying that various configurations could be adopted therein without deviating from the essence and gist of the present invention.