Patent Publication Number: US-2022226968-A1

Title: Tweezers Device

Description:
CROSS-REFERENCE 
     This application claims priority to and the benefit of JP application number JP2021-006845, filed on Jan. 20, 2021, and incorporated herein by reference in its entirety. 
     TECHNICAL FIELD 
     The present invention relates to a tweezers device. 
     BACKGROUND TECHNOLOGY 
     Conventionally, tweezers devices are known for use in soldering and desoldering work of electronic components. As disclosed in Patent Document 1 below, this type of tweezers device has a pair of leg rotatably connected by a hinge, and a soldering iron is attached to each of the pair of leg. In the tweezers device disclosed in Patent Document 1, as shown in FIG. 5, a spring 83 to urge the pair of leg 81, 82 in a direction where the end of the pair of leg 81, 82 spreads outward, and a screw 84 to limit the opening width between the end of the legs 81 and 82 is provided. By turning the screw 84, the acceptable width opening at the end of the pair of legs 81 and 82 can be changed, and the movement of the pair of legs 81 and 82 can be reduced which suppress deterioration of the work efficiency 
     PRIOR ART DOCUMENT 
     [Patent Document] 
     [Patent Document 1] U.S. Pat. No. 5,145,101 
     SUMMARY OF INVENTION 
     However, in tweezers device disclosed in Patent Document 1, the handling of the screw 84 to adjust the acceptable opening width at the end of the pair of legs 81 and 82 could be troublesome. That is, since the screw 84 is arranged on the hand side (on the proximal end than the hinge 85) of the pair of legs 81 and 82, the screw 84 cannot be operated by the hand holding the tweezers device, and need to operate the screw 84 with the other hand. 
     An object of the present invention is to provide a tweezers device which can easily perform the adjustment of the allowable opening width between the end of the pair of legs. 
     The tweezers device according to one aspect of the present invention has a first mounting portion for attaching a first tip, a first leg to hold said first mounting portion, a second mounting portion for attaching a second tip, a second leg to hold said second mounting portion, a rotating shaft to rotatably connect said first leg and said second leg, a bias member to bias said first leg and said second leg in a rotating direction of said rotating shaft, working to push away said first distal end of said first leg and said second distal end of said second leg, and an open width adjustment means including a rotatable width adjustment wheel, wherein an acceptable opening width between said first distal end and said second distal end is adjusted by the rotation of said width adjustment wheel. Said width adjustment wheel is positioned distally toward said first distal end and said second distal end than said rotating shaft, and is rotatable centering on the axis along the opening direction of said first distal end and said second distal end. 
     In the above tweezers device, the width adjusting wheel for adjusting the acceptable opening width between the first distal end of the first leg and the second distal end of the second leg is arranged on the distal side toward the first distal end and the second distal end than said rotating shaft. Therefore, using the thumb of the hand holding the tweezers device, the width adjusting wheel can be operated. Moreover, the axial center of the width adjusting wheel extends in the direction along the opening direction of the first distal end and the second distal end. Therefore, it is easy to rotate the width adjusting wheel in the direction in which the thumb of the hand holding the tweezers device can be moved. That is, it is easy to operate the width adjusting wheel with the hand holding the tweezers device. Therefore, the acceptable opening width between the ends of the pair of legs can be easily adjusted. Further, since the width adjusting wheel is located on the distal side of the rotation shaft, the tweezers device does not become large. 
     The bias member may include a leaf spring having a first end engaged to the first leg and a second end engaged to the second leg, which is placed along the first leg and the second leg. 
     In this embodiment, the leaf spring is used to bias the first leg and the second leg. Since the leaf spring is placed along the first leg or the second leg, the bias member can be made inconspicuous. 
     The tweezers device may further include an adjusting member to adjust the position between the first distal end of the first leg and the second distal end of the second leg in the direction of said rotating shaft. The adjusting member may include a position adjusting wheel and an eccentric shaft provided in a position eccentric from the center of said position adjusting wheel. Further, the leaf spring may be formed with an elongated hole. In this case, the eccentric shaft of said position adjusting wheel is inserted into said elongated hole, and by the rotation of said position adjusting wheel, the relative position between the first distal end and the second distal end is changed in the direction of said rotating shaft. 
     In this embodiment, the eccentric shaft revolves by rotating the position adjusting wheel, so the relative position of the position adjusting wheel center with respect to the leaf spring changes. As a result, the relative position between the first distal end and the second distal end in the direction of the rotation shaft changes. Therefore this could be used when it is desired to arrange the second distal end at a position slightly deviated from the first distal end in the rotating shaft direction, or when the first distal end and the second distal end are slightly deviated in the rotation axis direction and needs to be aligned. Moreover, the position between the first distal end and the second distal end can be adjusted with a simple configuration in which the eccentric shaft of the position adjusting wheel is inserted through the elongated hole formed in the leaf spring. 
     The tweezers device according to another aspect of the present invention, the tweezers device has a first mounting portion for attaching a first tip, a first leg to hold said first mounting portion, a second mounting portion for attaching a second tip, a second leg to hold said second mounting portion, a bias member having a first bias portion where the first mounting portion is fixed and a second bias portion where the second mounting portion is fixed, wherein the bias member bias the first leg and the second leg in a direction to push away said first distal end of said first leg and said second distal end of said second leg from each other, and an open width adjusting means including a rotatable width adjustment wheel, an acceptable opening width between the first distal end and the second distal end is adjusted by the rotation of the width adjustment wheel. The width adjustment wheel is rotatable centering on the axis along the opening direction of said first distal end and said second distal end at a position distally toward said first distal end and said second distal end than the connecting portion of said first bias portion and said second bias portion. 
     In the above tweezers device, the width adjusting wheel for adjusting an acceptable opening width between the first distal end of the first leg and the second distal end of the second leg is provided at a position of the first distal end and the second distal end side than the connecting portion of the first bias portion or the second bias portion. Therefore, with the thumb of the hand holding the tweezers device, the width adjusting wheel can be touched. Moreover, the axial center of the width adjusting wheel extends in the direction along the opening direction of the first distal end and the second distal end. Therefore, it is easy to rotate the width adjusting wheel in the direction in which the thumb of the hand holding the tweezers device can be moved. That is, it is easy to operate the width adjustment wheel with the hand holding the tweezers device. This makes the adjustment of the acceptable opening width between the distal ends of the pair of legs easy. Further, since the width adjusting wheel is located on the distal side than the connecting portion, the tweezers device does not become large. 
     In the above tweezers device, the width adjusting wheel may be in contact with a surface of the first leg opposite to the second leg. In this case, the open width adjusting means may include a stopper which is positioned on the second leg on the side opposite to the first leg, which the distance between the width adjusting wheel and the stopper changes by the rotation of the width adjusting wheel. The acceptable opening width is regulated by the stopper and the width adjusting wheel. 
     In this embodiment, the width adjusting wheel and the stopper are located on the outer side the first leg and the second leg. The acceptable opening width of the first distal end and the second distal end is adjusted by changing the distance between the width adjusting wheel and the stopper. 
     The acceptable opening width may be adjustable until the first soldering tip and the second soldering tip comes into contact. In this embodiment, a very small IC component may be pinched. Also, when the first tip and the second tip in contact to each other, the tweezers device may be used as a soldering iron. 
     The width adjusting wheel may be rotatably held in place so that it will not be pushed away from said first leg. 
     In this embodiment, since the width adjusting wheel is held so as not to be separated from the first leg, when the operation of closing both legs is performed, the width adjusting wheel will move along together with the first leg. Therefore, it is possible to avoid the width adjusting wheel falling off from the first leg. 
     The first mounting portion is positioned on the opposing side of the second leg with respect to said first leg, and a space may be formed between said first leg and second leg. In this case, the width adjusting wheel may be arranged within this space. 
     In this embodiment, the width adjusting wheel is provided in the space between the first mounting portion for mounting the first tip, and the first leg for holding the first mounting portion. That is, the width adjusting wheel is arranged in the space between the members required as a tweezers device. Therefore, it is possible to prevent the tweezers device from becoming large. 
     The above tweezers device may further include a positon adjusting wheel. In this case, upon rotation of the position adjusting wheel, it may adjust the position between the first distal end and the second distal end in the direction orthogonal to the virtual plane formed by the movement trace of the first leg and the second leg. 
     In this embodiment, a position adjusting wheel is provided in addition to the width adjusting wheel. The adjustment of acceptable opening width, and the adjustment of position between the first distal end and the second distal end in the rotating shaft direction are done by the rotation of respective wheels. Therefore, it is possible to provide a tweezers device that can perform two types of adjustments, and both adjustment are easy to operate. 
     The width adjusting wheel and the position adjusting wheel may be rotatable around the axis parallel to each other. 
     In this embodiment, the adjustment of the acceptable opening width and the adjustment of the position between the first distal end and the second distal end in the rotating shaft direction, can be done by operation in the same direction. 
     The above tweezers device may further comprise a housing which covers the first mounting portion and the second mounting portion. In this case, the width adjustment wheel and the position adjustment wheel may expose from said housing from the same direction. 
     In this embodiment, the two adjustments (adjustment of the acceptable opening width and adjustment of the position between the first distal end and the second distal end in the rotation shaft direction) may be accessed from the same direction with respect to the housing. Therefore, the two adjustments can be made without changing the orientation of the housing. 
     The housing may have a first housing which covers said first mounting portion, and a second housing which covers said second mounting portion. In this case, the width adjusting wheel may be arranged in said first housing so a part of the width adjusting wheel expose from said first housing, and the positon adjusting wheel may be arranged in said second housing so a part of said position adjusting wheel expose from said second housing. 
     In this embodiment, the width adjusting wheel and the position adjusting wheel are separately arranged in the first housing and the second housing. Therefore, when using the tweezers device, it becomes easy to distinguish the width adjustment wheel and the position adjustment wheel. 
     The width adjusting wheel and the position adjusting wheel may be arranged that it will partially overlap when seen from side view. 
     In this embodiment, the space required for arranging the width adjusting wheel and the position adjusting wheel can be suppressed. Therefore, it is possible to prevent the tweezers from becoming large. 
     As described above, according to the present invention, the adjustment of the acceptable opening width between the ends of the pair of legs may be easily performed. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of a soldering device to which the tweezers device according to the first embodiment is applied. 
         FIG. 2  is a view showing the tweezers device with the housing removed. 
         FIG. 3  is a view showing a part of the tweezers device, seen from the side of the second leg. 
         FIG. 4  is a perspective view showing the tweezers device with the housing removed. 
         FIG. 5  is a view showing a tweezers device according to a second embodiment with the housing removed. 
         FIG. 6  is a view of a modification of a biasing member provided in the tweezers device according to the second embodiment. 
         FIG. 7  is a view of a conventional tweezers device. 
     
    
    
     DETAILED DESCRIPTION 
     The embodiments of the present invention will be described in detail with reference to the drawings below. 
     As shown in  FIG. 1 , the tweezers device  10  according to the first embodiment is used by attaching a pair of soldering tips  1  and  2 . By attaching the pair of tips  1  and  2  (first tip and second tip) to the tweezer device  10 , a soldering device  5  for attaching/detaching electronic components is configured. 
     The tweezers device  10  includes a housing  12 , having a first housing  12   a  on the side where the first tip  1  is held, a second housing  12   b  on the side where the second tip  2  is held, and a proximal housing  12   c  located on the proximal end side of the first housing  12   a  and the second housing  12   b.    
     As shown in  FIG. 2 , the tweezers device  10  includes a first mounting portion  15  configured to mount the first tip  1 , a first leg  16  to hold the first mounting portion  15 , a second mounting portion  17  configured to mount the second tips  2 , second leg  18  to hold the second mounting portion  17 , and a rotating shaft  19  to rotatably connect the first leg  16  and the second leg  18 . Although the housing  12  is omitted in  FIG. 2 , the first housing  12   a  is attached to the first leg  16 , and the base portion  15   a  of the proximal first mounting portion  15  is arranged in the first housing  12   a . Further, the second housing  12   b  is attached to the second leg  18 , and the base portion  17   a  of the second mounting portion  17 , which will be described later, is arranged in the second housing  12   b.    
     A power supply line  21  is connected to the first mounting portion  15 , and the electric power supplied through the power supply line  21  causes the first tip  1  attached to the first mounting portion  15  to generate heat. The power supply line  21  is also connected to the second mounting portion  17 , and by the electric power supplied through the power supply line  21 , the second tip  2  attached to the second mounting portion  17  generates heat. 
     The first mounting portion  15  is positioned on the opposite side of the second leg  18  relative to the first leg  16 . The second mounting portion  17  is positioned on the opposite side of the first leg  16  relative to the second leg  18 . That is, the first mounting portion  15  and the second mounting portion  17  are positioned outside of the first leg  16  and the second leg  18 . 
     Further, a space  20   a  is formed between the first mounting portion  15  and the first leg  16 , and also a space  20   b  is formed between the second mounting portion  17  and the second leg  18 . The first mounting portion  15  is held by the first leg  16  inclined with respect to the first leg  16 , and the second mounting portion  17  is held by the second leg  18  inclined with respect to the second leg  18 . 
     That is, the first mounting portion  15  is held by the first leg  16  so the first tip  1  faces inward with respect to the extending direction of the first leg. Further, the second mounting portion  17  is held by the second leg  18  so that the second tip  2  faces inward with respect to the extending direction of the second leg  18 . 
     The first mounting portion  15  is held by the first leg  16  and the first housing  12   a  via the first connecting portion  25 . The second mounting portion  17  is held by the second leg  18  and the second housing  12   b  via the second connecting portion  26 . 
     The first mounting portion  15  is arranged in the space defined by the first housing  12   a  and the first leg  16 , and the second mounting portion  17  is arranged in the space defined by the second housing  12   b  and the second leg  18 . On the other hand, the first connecting portion  25  is arranged so it will expose at the distal end of the first housing  12   a  (upper end in  FIG. 2 ), and the second connecting portion  26  is arranged so it will expose at the distal end of the second housing  12   b  (upper end in  FIG. 2 )(See  FIG. 1 ). However, the first leg  16  may be arranged so it will be covered by the first housing  12   a , and the second leg  18  may be arranged so it will be covered by the second housing  12   b.    
     The first connecting portion  25  is held sandwiched between the distal end (the upper end in  FIG. 2 ) of the first leg  16  and the first housing  12   a . However, the first connecting portion  25  is not limited to the configuration positioned at the distal end of the first leg  16 , and for example, may be arranged at an intermediate position of the first leg  16 . 
     The first mounting portion  15  and the second mounting portion  17  has same configuration, and also the first connecting portion  25  and the second connecting portion  26  has the same configuration. Since  FIG. 3  shows the second mounting portion  17  and the second connection portion  26 , here, with reference to  FIG. 3 , the configurations of the second mounting portion  17  and the second connecting portion  26  will be described. 
     The second connecting portion  26  is formed by an annular member, so the second mounting portion  17  is inserted. The second connecting portion  26  has a knob  26   a  with plurality of convex arranged in the circumferential direction, and a cylindrical portion  26   b  on the proximal side of the knobs  26   a . The cylindrical portion  26   b  is positioned inside the second housing  12   b , and is rotatably held between a second holding portion  18   b  of the second leg  18  and the second housing  12   b . On the other hand, the knob  26   a  is exposed outside of the second housing  12   b  and is used to rotate the second connecting portion  26 . 
     The second mounting portion  17  has a base portion  17   a , and a top portion  17   b  that is formed separately from the base portion  17   a  and is located on the distal side of the base portion  17   a.    
     The second tip  2  is inserted through the top portion  17   b  into the base portion  17   a , and is supported by the base portion  17   a . The top portion  17   b  is connected to the base portion  17   a  inside the second connecting portion  26 , and is rotatable with respect to the base portion  17   a . When the top portion  17   b  is rotated with respect to the base portion  17   a , it is configured that the second tip  2  held by the base portion  17   a  will rotate. 
     A protrusion  17   c  is provided on the top portion  17   b , and the protrusion  17   c  can engage with the convex stopper  18   e  formed on the second leg  18  when the top portion  17   b  is rotated. As a result, the rotation range of the top portion  17   b , that is, the rotation range of the second tip  2  is regulated. 
     A female screw  26   d  is provided on the inner surface of the cylindrical portion  26   b  of the second connecting portion  26 . On the other hand, a male screw  17   d  is provided on the outer surface of the tip of the base portion  17   a  of the second mounting portion  17 , and the male screw  17   d  is screwed into the female screw  26   d  of the second connecting portion  26 . Therefore, when the knob  26   a  of the second connecting portion  26  is rotated, the second mounting portion  17  is displaced with respect to the second connecting portion  26  in a front-rear direction (vertical direction in  FIG. 2 ). As a result, the second tip  2  attached to the second mounting portion  17  can be displaced in the front-rear direction. 
     Since the first connecting portion  25  is also configured in the same manner as the second connecting portion  26 , the first tip  1  attached to the first mounting portion  15  may be displaced in the front-rear direction, and also the first tip  1  may be rotated. Therefore, the relative position between the ends of the first tip  1  and the second tip  2  in the front-rear direction can be adjusted. 
     Returning to  FIG. 2 , as shown, the first leg  16  and the second leg  18  are connected to the rotating shaft  19  at the proximal end (lower end in  FIG. 2 ). The first leg  16  and the second leg  18  are each provided with a through hole which the rotating shaft  19  penetrates through. The first leg  16  is formed in a shape extending in one direction from the hole toward its distal end, and the second leg  18  is formed in a shape extending in one direction from the hole toward its distal end. At the distal end of the first leg  16 , a first holding portion  16   b  is formed for holding the cylindrical portion  25   b  of the first connecting portion  25  together with the first housing  12   a . Likely, at the distal end of the second leg  18 , a second holding portion  18   b  is formed for holding the cylindrical portion  26   b  of the second connecting portion  26  together with the second housing  12   b . The first leg  16  and the second leg  18  are made of resin. 
     On the first leg  16 , a block base  16   c  is provided at the proximal side of the hole. The power supply line  21  is arranged above of the base  16   c . Further, a leaf spring  30  is fixed to the base  16   c.    
     The leaf spring  30  works as a bias member to bias the first leg  16  and the second leg  18 , in a direction so the first distal end  16   d  of the first leg  16  and the second distal end  18   d  of the second leg  18  are pushed away from each other. The leaf spring  30  extends from the base  16   c  of the first leg  16  to the second leg  18 , along the outer surfaces of the first leg  16  and the second leg  18 . The leaf spring  30  has a first end  30   a  engaged to the first leg  16  and a second end  30   b  engaged to the second leg  18 . 
     The first end  30   a  of the leaf spring  30  is fixed to a side surface  16   e  of the base  16   c , where the side surface  16   e  extends in a longitudinal direction (vertical direction in  FIG. 2 ). When the virtual line of the side surface  16   e  is extended, it will be orthogonal to or substantially orthogonal to a shaft member  33   a  described later. The flat surface of the leaf spring  30  contacts the side surface  16   e  of the base  16   c , and extends distally. Therefore, when the position of the second end  30   b  of the leaf spring  30  is displaced by elastic deformation and urged toward the second leg  18  with respect to the virtually extended surface of the side surface  16   e  of the base  16   c , a bias force is generated in the direction in where the first distal end  16   d  of the first leg  16  and the second distal end  18   d  of the second leg  18  are pushed away from each other. 
     Therefore, when first tip  1  and second tip  2  are pushed close to each other in operation, a restoring force is generated in the leaf spring  30 . 
     The leaf spring  30  urges the first distal end  16   d  of the first leg  16  and the second distal end  18   d  of the second leg  18  to move away from each other. The acceptable opening width between  16   d  and  18   d  may be regulated by the width adjusting wheel  33   b  and the stopper  33   c , which will be described later. 
     The tweezers device  10  is provided with an open width adjusting means  33  for adjusting the allowable open width between the first distal end  16   d  and the second distal end  18   d.    
     Specifically, the open width adjusting means  33  includes a shaft  33   a  bridged between the first leg  16  and the second leg  18 , a width adjusting wheel  33   b  for performing the adjustment of allowable width, a stopper  33   c  to regulate the open width between the first leg  16  and the second leg  18  together with the width adjusting wheel  33   b , and a displacement means  33   d  to change the position of the width adjusting wheel  33   b  against the shaft  33   a.    
     The shaft member  33   a  has one end inserted into a through hole formed in the first leg  16  and the other end inserted into a through hole formed in the second leg  18 . The axial center of the shaft  33   a  extends in a direction along the opening direction of the first distal end  16   d  and the second distal end  18   d . The direction of this axial center is orthogonal to the rotation shaft  19 . In the present embodiment, the shaft  33   a  is inserted through the through hole so as not to rotate around the axis. For example, the shaft member  33   a  has a non-circular cross section instead of a circular cross section to avoid rotation. 
     The width adjusting wheel  33   b  and the stopper  33   c  are arranged to sandwich the first leg  16  and the second leg  18 . That is, the width adjusting wheel  33   b  is provided on the opposite side of the second leg  18  with respect to the first leg  16 , and the stopper is provided on the opposite side of the first leg  16  with respect to the second leg  18 . 
     The stopper  33   c  is provided at the end of the shaft  33   a , has a width larger than the shaft  33   a , and is formed in a size that will not go through the through hole. Therefore, the shaft  33   a  will not come off from the through hole of the second leg  18 . Here, the stopper  33   c  is formed integrally with the shaft  33   a , however, it may be formed separately from the shaft  33   a  and then fixed to the shaft  33   a.    
     With the shaft  33   a , the displacement means  33   d  includes a male screw  33   e  formed on the end opposite to the end where the stopper  33   c  is provided, and a female screw  33   f  provided on the inner surface of the width adjusting wheel  33   b , the width adjusting wheel  33   b  formed annular and to fit on the shaft  33   a . Therefore, when the width adjusting wheel  33   b  is rotated with respect to the shaft  33   a , the width adjusting wheel displaces in the direction of the axial center of the shaft  33   a , which will change the width of the width adjusting wheel  33   b  and the stopper  33   c . As a result, the acceptable opening width of the first leg  16  and the second leg  18  are adjusted. In the embodiment, this acceptable opening width can be minimized until the first tip  1  and the second tip  2  comes into contact with each other. The female screw  33   f  on the inner surface of the width adjusting wheel  33   b  may be formed as a nut embedded in the width adjusting wheel. 
     The width adjusting wheel  33   b  is provided in the wheel holding portion (first wheel holding portion)  16   f  formed on the first leg  16 , and is rotatably held in position by the first wheel holding portion and the first housing  12   a.    
     The first wheel holding portion  16   f  is located at an intermediate portion between the first distal end  16   d  and the base end (hole that supports the rotating shaft  19 ) of the first leg  16 , and is located outside the first leg  16  (opposite side of the second leg  18 ), and is integrally formed with the first leg  16 . Therefore, the width adjusting wheel  33   b  is arranged on the distal side of the rotating shaft  19 . In other words, the width adjusting wheel  33   b  is arranged at positions closer to the first distal end  16   d  and the second distal end  18   d  than the rotating shaft  19 . 
     The first wheel holding portion  16   f  has an inner peripheral surface matching the outer peripheral surface of the width adjusting wheel  33   b , and the first housing  12   a  is adjacent to the first wheel holding portion  16   f . Therefore, the width adjusting wheel  33   b  is held in place so as not to get away from the first wheel holding portion  16   f . That is, the width adjusting wheel  33   b  is held in place with the first leg  16 . Therefore, even if the position of the width adjusting wheel  33   b  with respect to the shaft  33   a  is displaced, the position of the width adjusting wheel  33   b  with respect to the first leg  16  does not change. Meanwhile, when the first tip  1  and the second tip  2  are operated to bring close to each other (not the adjustment of the opening width but the closing operation for pinching the electronic component), the first leg will not go away from the width adjusting wheel  33   b , but the second leg  18  will separate away from the stopper  33   c.    
     The width adjusting wheel  33   b  is arranged in the space  20   a  between the first leg  16  and the first mounting portion  15 . 
     The tweezers device  10  further includes an adjusting member  36  which adjust the relative position between the first distal end  16   d  of the first leg  16  and the second distal end  18   d  of the second leg  18  in the extending direction of the rotating shaft  19 . The adjusting member  36  adjusts the relative position of the first distal end  16   d  and the second distal end  18   d  in a direction orthogonal to the virtual plane formed by the movement trace of the first leg  16  and the second leg  18  (i.e. direction orthogonal to the paper surface of  FIG. 2 ). 
     The adjusting member  36  includes a position adjusting wheel  36   a  and an eccentric shaft  36   b . As shown in  FIG. 4 , the position adjusting wheel  36   a  is rotatably held by the second wheel holding portion  18   f  provided on the second leg  18 , and is arranged at a position in the distal side than the rotating shaft  19 . In other words, the position adjusting wheel  36   a  is arranged at position closer to the first distal end  16   d  and the second distal end  18   d  than the rotation shaft  19 . The second wheel holding portion  18   f  is provided on the surface of the second leg  18  opposite to the first leg  16 . The second wheel holding portion  18   f  is arranged at a position closer to the rotation shaft  19  than the first wheel holding portion  16   f . That is, the first wheel holding portion  16   f  and the second wheel holding portion  18   f  are arranged at positions shifted in the front-rear direction. Therefore, the width adjusting wheel  33   b  and the position adjusting wheel  36   a  are also shifted in the front-rear direction. However, the width adjusting wheel  33   b  and the position adjusting wheel  36   a  may be arranged to partially overlap when seen from a side view (viewed from the extending direction of the shaft member  33   a ). Therefore, it is possible to prevent the first leg  16  and the second leg  18  from becoming too long or big in the front-rear direction to arrange the wheels  33   b  and  36   a.    
     The eccentric shaft  36   b  is bridged between the first leg  16  and the leaf spring  30 . Therefore, the position adjusting wheel  36   a  is prevented from tilting. Further, the eccentric shaft  36   b  is arranged parallel with the shaft  33   a . Therefore, the width adjusting wheel  33   b  and the position adjusting wheel  36   a  can rotate around an axis parallel to each other. This will allow both wheels  33   b  and  36   a  to be operated in the same direction. 
     The eccentric shaft  36   b  is fixed to the position adjusting wheel  36   a  eccentric from the center of the position adjusting wheel  36   a . The eccentric shaft  36   b  is inserted into the elongated hole  16   g  (see  FIG. 4 ) formed on the first leg  16 , and into the elongated hole  30   c  (see  FIG. 3 ) formed in the leaf spring  30 . 
     The elongated hole  16   g  and the elongated hole  30   c  have lengths that cover the range in which the eccentric shaft  36   b  revolves. Therefore, when the eccentric shaft  36   b  revolves by the position adjusting wheel  36   a  being rotated, the eccentric shaft  36   b  will show reciprocate movement in the elongated hole  16   g  and the elongated hole  30   c.    
     When the eccentric shaft  36   b  revolves, the first leg  16  will cause a swing movement having the connecting portion of the rotating shaft  19  as the center, so the first distal end  16   d  will displace with respect to the second distal end  18   d  in the extending direction of the rotating shaft  19 . Accompanied by this swing movement, the relative position of the first distal end  16   d  of the first leg  16  and the second distal end  18   d  of the second leg  18  will change in direction of the rotating shaft  19 . The connecting portion between the second leg  18  and the first leg  16  has some play that will allow this swing movement. Since the first end  30   a  of the leaf spring  30  is coupled to the base  16   c  of the first leg  16 , by the revolution of the eccentric shaft  36   b , the leaf spring  30  will swing around the connection portion of the rotating shaft  19  as the center. 
     As shown in  FIG. 1 , the width adjusting wheel  33   b  and the position adjusting wheel  36   a  are exposed from the housing  12  in the same direction. That is, the housing  12  has a pair of surfaces (upper surface and lower surface in  FIG. 1 ) facing opposite to each other, and the both of the width adjusting wheel  33   b  and the position adjusting wheel  36   a  are exposed from only one of the surface (upper surface in  FIG. 1 ). The pair of surfaces face opposite to each other in the extending direction of the rotation shaft  19 . 
     The width adjusting wheel  33   b  expose from the first housing  12   a , and the position adjusting wheel  36   a  expose from the second housing  12   b . That is, the width adjusting wheel  33   b  is arranged on the first housing  12   a  side partially exposed, and the position adjusting wheel  36   a  is arranged on the second housing  12   b  side partially exposed. Since the width adjusting wheel  33   b  and the position adjusting wheel  36   a  are separately arranged in the first housing  12   a  and the second housing  12   b , it is easy to distinguish the two wheels  33   b  and  36   a  when the tweezers device  10  is used, which avoids the wheels being mistakenly operated. 
     As described above, in the present embodiment, the width adjusting wheel  33   b  for adjusting the acceptable opening width between the first distal end  16   d  of the first leg  16  and the second distal end  18   d  of the second leg  18  is provided at a distal position (toward first distal end  16   d  and second distal end  18   d ) than the rotation shaft  19 . 
     Therefore, when holding the tweezers device  10 , the thumb of the hand holding the first leg  16  and the second leg  18  can touch the width adjusting wheel  33   b . Moreover, the shaft  33   a  extends in a direction parallel to the direction connecting the first distal end  16   d  and the second distal end  18   d . Therefore, it is easy to rotate the width adjusting wheel  33   b  in the direction which the thumb will move while the hand holding the first leg  16  and the second leg  18 . That is, it is easy to operate the width adjusting wheel  33   b  with the hand holding the tweezers device  10 . Therefore, the acceptable opening width between the ends  16   d  and  18   d  of the pair of legs  16  and  18  can be easily adjusted. Further, since the width adjusting wheel  33   b  is located on the distal side than the rotating shaft  19 , the tweezers device  10  does not become large. 
     Further, in the present embodiment, the acceptable opening width can be adjusted until the first tip  1  and the second tip  2  come into contact with each other, so a very small electronic component may be pinched by the soldering device  5 . Further, when the first tip  1  and the second tip  2  are used in contact with each other, it can also be used as a soldering iron having double heat capacity. 
     Further, in the present embodiment, since the width adjusting wheel  33   b  is held by the first wheel holding portion  16   f  of the first leg  16 , it is possible to rotate the width adjusting wheel  33   b  without providing a support of the shaft  33   a  on the first leg  16 . Further, since the width adjusting wheel  33   b  is hold in place in the first leg  16 , when the operation of pinching/closing the legs  16  and  18  is performed, the width adjusting wheel  33   b  moves together with the first leg  16 . Therefore, it is possible to avoid the width adjusting wheel  33   b  falling off from the first leg  16 . When the legs  16   d  and  18   d  are closed/pinched, even the width adjusting wheel  33   b  is held in place together with the first leg  16 , the operation of closing the legs  16  and  18  is not hindered since the stopper  33   c  will be pushed away from the second leg  18 . 
     Further, in the present embodiment, the width adjusting wheel  33   b  is arranged in the space  20   a  between the first mounting portion  15  and the first leg  16 . That is, the width adjusting wheel  33   b  is arranged in the space between the components required for the tweezers device  10 . Therefore, it is possible to prevent the tweezers device  10  from becoming large in size. 
     Further, in the present embodiment, a leaf spring  30  is used to urge the first leg  16  and the second leg  18  away, and the leaf spring  30  is provided along the first leg  16  or the second leg  18 . Therefore, the bias member that urge the legs  16  and  18  can be made inconspicuous or hided. 
     Further, in the present embodiment, by rotating the position adjusting wheel  36   a , the eccentric shaft  36   b  revolves and the relative position of the center of the position adjusting wheel  36   a  with respect to the leaf spring  30  changes. As a result, the relative position between the first distal end  16   d  and the second distal end  18   d  in the extending direction of the rotation shaft  19  changes. Therefore, this function can deal in cases when it is desired to arrange the second distal end  18   d  at a position slightly deviated from the first distal end  16   d  in the rotation shaft  19  direction, or when the first distal end  16   d  and the second distal end  18   d  are slightly deviated in the rotation shaft  19  direction and needs to be aligned. Moreover, the position adjustment between the first distal end  16   d  and the second distal end  18   d  can be performed with a simple configuration in which the eccentric shaft  36   b  of the position adjusting wheel  36   a  is inserted through the elongated hole  30   c  formed in the leaf spring  30 . 
     Further, the acceptable opening width and the position adjustment between the first distal end  16   d  and the second distal end  18   d  in the rotation shaft  19  direction is adjusted by rotating the wheels  33   b  and  36   a , respectively. Therefore, the tweezers device  10  can perform two types of adjustment operations, and each of the adjustment operation can be easily performed. 
     Further, in the present embodiment, the width adjusting wheel  33   b  and the position adjusting wheel  36   a  are exposed from the housing  12  in the same direction, so the two adjustments (adjustment of acceptable opening width and the position adjustment between the first distal end  16   d  and the second distal end  18   d  in the rotating shaft  19  direction) may be accessed from the same side with respect to the housing  12 . This allows the adjustment to be performed without changing the orientation of the housing  12 . 
       FIG. 5  shows the tweezers device  50  according to the second embodiment. In  FIG. 5 , the tweezers device  50  is shown with the first housing  12   a  and the second housing  12   b  removed. Here, the same components as those in the first embodiment are indicated by the same reference numerals, and detailed description thereof will be omitted. 
     In the first embodiment, a rotation shaft  19  for rotatably connecting the first leg  16  and the second leg  18  is provided. On the other hand, in the tweezers device  50  of the second embodiment, the first leg  16  and the second leg  18  can be closed/pinched without the rotating shaft  19  being provided. 
     Specifically, the tweezers device  50  includes a bias member  52  having a first bias portion  52   a  and a second bias portion  52   b . The bias member  52  has a connecting portion  52   c  that connects the proximal end of the first bias portion  52   a  and the proximal end of the second bias portion  52   b . The bias member  52  is biased in a direction which the distal end of the first bias portion  52   a  and the distal end of the second bias portion  52   b  are pushed away from each other (opening direction). The first leg  16  is fixed to the first bias portion  52   a  on the distal side than the connecting portion  52   c , and the second leg  18  is fixed to the second bias portion  52   b  on the distal side than the connecting portion  52   c.    
     The bias member  52  has an elastic force in a direction in which the first distal end  16   d  of the first leg  16  and the second distal end  18   d  of the second leg  18  are pushed away from each other. The acceptable opening width of the first leg  16  (or the first bias portion  52   a ) and the second leg  18  (or the second bias portion  52   b ) is adjusted by the width adjusting wheel  33   b  and the stopper  33   c.    
     The width adjusting wheel  33   b  is positioned close to the first distal end  16   d  and the second distal end  18   d  than the connecting portion  52   c  of the end of the first bias member  52   a  and the end of the second bias member  52   b . The axial center of the width adjusting wheel  33   b , that is, the axial center of the shaft  33   a  is along with the opening direction of the first distal end  16   d  and the second distal end  18   d.    
     Therefore, in the second embodiment, the width adjusting wheel  33   b  for adjusting the acceptable opening width between the first distal end  16   d  of the first leg  16  and the second distal end  18   d  of the second leg  18  is arranged at a position closer to the first distal end  16   d  and the second distal end  18   d  than the connecting portion  52   c  of the first bias portion  52   a  and the second bias portion  52   b . Therefore, the hand holding the tweezers device  50  can touch the width adjusting wheel  33   b  with its thumb. Moreover, the axial center of the width adjusting wheel  33   b  extends in the direction along the opening direction of the first distal end  16   d  and the second distal end  18   d . Therefore, it is easy to rotate the width adjusting wheel  33   b  in the direction in which the thumb of the hand holding the tweezers device  50  can be moved. That is, it is easy to operate the width adjusting wheel  33   b  with the hand holding the tweezers device  50 . Therefore, the acceptable opening width between the ends  16   d  and  18   b  of the pair of legs  16  and  18  can be easily adjusted. Further, since the width adjusting wheel  50  is located on the distal side than the connecting portion  52   c , the tweezers device  50  does not become large. 
     In the bias member  52  shown in  FIG. 5 , the connecting portion  52   c  is configured that the surface of the first bias portion  52   a  and the second bias portion  52   b  is fixed together. However, it is not limited to this and for example, as shown in  FIG. 6 , the connecting portion  52   c  may have a configuration in which the end of the first bias portion  52   a  and the end of the second bias portion  52   b  are connected in series so as to have a continuous curved shape. 
     Although the description of other configurations, actions, and effects will be omitted, the description of the first embodiment can be incorporated into the second embodiment. 
     It should be noted that the embodiments disclosed are exemplary in all respects and are not considered to be restrictive. The present invention is not limited to the embodiment described above, and various modifications and improvements can be made without departing from the spirit of the present invention. For example, in the first and second embodiments, the acceptable opening width is adjusted by rotating the female screw  33   f  of the width adjusting wheel  33   b  with respect to the male screw  33   e  of the shaft  33   a , but the configuration is not limited to this. For example, the width adjusting wheel  33   b  may be integrally formed with the shaft  33   a  so that the shaft  33   a  also rotates. In this case, the female screw  33   f  is fixed to the first leg  16  and this female screw  33   f  may screw with the male screw  33   e  of the shaft member  33   a.    
     Further, when the width adjusting wheel  33   b  is provided integrally with the shaft member  33   a , the width adjusting wheel  33   b  may be allowed to be pushed away from the first leg  16 . In this case, the stopper  33   c  may be provided with the female screw  33   f , and the shaft  33   a  may be provided with the male screw  33   e , which will screw with the female screw portion  33   f . In this case, the stopper  33   c  will not be pushed away from the second leg  18 . 
     In the first and second embodiments, the width adjusting wheel  33   b  and the stopper  33   c  sandwich the first leg  16  and the second leg  18  from both sides, but the present invention is not limited to this. For example, the width adjusting wheel  33   b  may be arranged between the first leg  16  and the second leg  18 , while the shaft  33   a  being provided with a female screw (not shown) at the end opposite to the stopper  33   c , and the first leg  16  and the second leg  18  may be sandwiched from both sides by this female screw and the stopper  33   c.    
     In the first embodiment, the base  16   c  which the leaf spring  30  is engaged is provided on the first leg  16 , but the base which the leaf spring  30  is engaged may be provided on the second leg  18  instead of the first leg  16 , in the position where the base  16   c  is provided in  FIG. 2 . In this case, the second end  30   b  of the leaf spring  30  may be engaged to the base of the second leg  18 , and the first end  30   a  of the leaf spring  30  engaged to the first leg  16  will position to the distal side than the base of the second leg  18 . That is, the front-rear relationship between the first end portion  30   a  and the second end portion  30   b  is opposite to that of the first embodiment, and the leaf spring  30  extends in a direction along the base of the second leg  18  to the first leg  16 . 
     In the first embodiment, the leaf spring  30  is formed in a shape extending in one direction from the base  16   c  of the first leg  16  along the second leg  18 , but is not limited to this configuration. For example, the leaf spring  30  may be formed in a U shape and arranged along the first leg  16  and the second leg  18 . That is, the leaf spring  30  will have a configuration including a first portion located outside the first leg  16 , a second portion located outside the second leg  18 , and a connecting portion to connect the end of the first portion and the second portion. In this case, the leaf spring  30  may be arranged along the outer surface of the first leg  16  and the second leg  18 , or may be arranged along the inner surface. 
     Further, in the first embodiment, the leaf spring  30  is used as the bias member for biasing the first leg  16  and the second leg  18 , but a coil spring may be used instead of the leaf spring  30 . In this case, the coil spring will be arranged between the first leg  16  and the second leg  18  in a compressed state. 
     In the first and second embodiments, the connecting portions  25  and  26  are provided, and the first connecting portion  25  is configured so the first mounting portion  15  can be displaced in the front-rear direction with respect to the first leg  16 , but is not limited to this configuration. For example, the first connecting portion  25  may be configured so the first mounting portion  15  will not move. Further, the first connection portion  25  may be omitted. In this case, the first mounting portion  15  will be held by the first leg  16  and the first housing  12   a  without moving in front-rear direction. The second connection portion  26  can also be omitted in the same manner. 
     The first mounting portion  15  rotatably holds the first tip  1 , but is not limited to this configuration. The first mounting portion  15  may be configured to hold the first tip  1  so it will not rotate. This is same with the second mounting portion  17 . 
     In the above embodiment, the width adjusting wheel  33   b  is arranged in the space  20   a  between the first mounting portion  15  and the first leg  16 , but is not limited to this configuration. The width adjusting wheel  33   b  may be arranged at a position overlapping the first mounting portion  15 . 
     In the first embodiment, an adjusting member  36  for adjusting the position between the first tip  1  and the second tip  2  in the direction of the rotation shaft  19  is provided, but the adjusting member  36  may be omitted. Further, the adjusting member  36  may be configured to adjust the position without using the leaf spring  30 . 
     The width adjusting wheel  33   b  and the position adjusting wheel  36   a  may be exposed from the housing  12  in different directions. Further, the width adjusting wheel  33   b  and the position adjusting wheel  36   a  may both be arranged in the first housing  12   a.    
     EXPLANATION OF SYMBOLS 
     
         
           1 : first tip 
           2 : Second tip 
           10 : Tweezers device 
           12 : Housing 
           12   a : First housing 
           12   b : Second housing 
           15 : First mounting portion 
           16 : First leg 
           16   d : First distal end 
           16   f : First wheel holding portion 
           17 : Second mounting portion 
           18 : Second leg 
           18   d : Second tip 
           19 : Rotating shaft 
           20   a : Space 
           30 : Leaf spring 
           30   a : First end 
           30   b : Second end 
           30   c : Elongated hole 
           33 : Open width adjusting means 
           33   b : Width adjustment wheel 
           33   c : Stopper 
           36 : Adjusting member 
           36   a : Position adjustment wheel 
           36   b : Eccentric shaft 
           50 : Tweezers device 
           52 : Bias member 
           52   a : first bias portion 
           52   b : second bias portion