Method for manufacturing an opening / closing chuck and its fingers

Abstract

To provide an opening / closing chuck that improves the gripping force of work and enables the gripping of work at a position further separated from a supporting position of a finger, by easing stress concentration generated in the finger due to a load acting on the finger and three-dimensional various axial moment.SOLUTION: A finger 14 has a pair of bulging portions 16 and 18 projecting out from a body portion 20 to a side part. Outer peripheral surfaces of the bulging portions are composed of upper surfaces 16a and 18a, side surfaces 16b and 18b, lower surfaces 16c and 18c, first end surfaces 16d and 18d, and second end surfaces 16e and 18e. Crowning is performed at intersecting portions of those surfaces.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to an opening and closing chuck having a pair of fingers for gripping a workpiece and a method for manufacturing the fingers.

Background Art

[0002] Conventionally, an opening and closing chuck that supports a pair of fingers for gripping a workpiece so as to be slidable in directions of approaching and separating from each other is known. For example, Patent Document 1 describes a parallel gripper provided with a wedge hook transmission part that moves two base jaws guided movably in a housing closer to or away from each other, and adjusts the wedge hook transmission part by a piston.

[0003] Further, Patent Document 2 describes that in a grip device provided with a pair of slides, by providing a lamp on a guide flange of each slide, a wedge gap that expands toward an end face of the slide is formed.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] When gripping a workpiece using a pair of slidably supported fingers, the fingers are subjected to a load in a predetermined direction (vertical or lateral) due to the reaction force from the workpiece, as well as a moment that attempts to rotate the fingers around various axes in three dimensions. The load and moment acting on the fingers increase as the gripping force on the workpiece increases. Furthermore, the moment acting on the fingers increases as the distance between the gripping position of the workpiece on the gripping member (attachment) extending from the fingers and the support position of the fingers increases. If the load and moment acting on the fingers are large, stress concentration occurs at the contact surface between the fingers and the body, generating excessive surface pressure and damaging the sliding surfaces of the fingers and the body.

[0006] However, technologies that take into account the stress concentration that occurs in the fingers and body described above have not yet been sufficiently developed. The technology described in Patent Document 2 is somewhat effective in mitigating stress concentration that occurs when the opposing ends of a pair of slides attempt to rotate so that they open at an angle, and in preventing excessive surface pressure, but it does not take into account the fact that moments around various three-dimensional axes act on the slides.

[0007] The present invention has been made in view of the above circumstances, and aims to provide an opening / closing chuck and a method for manufacturing the fingers thereof, which enhances the gripping force of the workpiece and enables gripping of the workpiece at a position further away from the support position of the fingers by mitigating stress concentration that occurs at the contact surface between the fingers and the body due to loads such as vertical loads acting on the fingers and moments around various three-dimensional axes. [Means for solving the problem]

[0008] The opening and closing chuck according to the present invention includes a pair of fingers that slide within a guide groove of the body and are supported to slide freely in directions toward and toward each other. The fingers have a pair of overhangs that project laterally from the main body, and the outer circumferential surface of the overhangs consists of five surfaces: an upper surface, a side surface, a lower surface, a first end surface, and a second end surface, with crowning applied to the intersections of these surfaces.

[0009] The above-described opening and closing chuck can alleviate stress concentration on the fingers caused by vertical and other loads acting on the fingers, as well as moments around the three axes, thereby reducing the maximum surface pressure.

[0010] Furthermore, the first method for manufacturing a finger according to the present invention relates to a finger that slides within a guide groove of the body of an opening and closing chuck, is supported so as to be slidable in directions approaching and separating from each other, has a pair of protruding portions that project laterally from the main body, the outer circumferential surface of the protruding portions consists of five surfaces: an upper surface, a side surface, a lower surface, a first end surface, and a second end surface, the upper surface and lower surface being perpendicular to the side surface, and includes a step of crowning the intersections of the five surfaces by combining grinding the side surface with a first processing tool and grinding the upper surface and lower surface with a second processing tool.

[0011] Furthermore, the second method for manufacturing a finger according to the present invention relates to a finger that slides within a guide groove of the body of an opening and closing chuck, is slidably supported in directions approaching and separating from each other, has a pair of protruding portions that project laterally from the main body, the outer circumferential surface of the protruding portions consists of five surfaces: an upper surface, a side surface, a lower surface, a first end surface, and a second end surface, and the upper and lower surfaces are tapered surfaces that become closer to each other as they approach the side surface, and includes a step of simultaneously grinding the side surface and the upper and lower surfaces using a single processing tool, thereby crowning the intersections of the five surfaces.

[0012] According to the first and second manufacturing methods described above, crowning, which is necessary to alleviate stress concentration in the fingers and body caused by vertical loads and triaxial moments acting on the fingers, can be easily performed in fewer steps. [Effects of the Invention]

[0013] The opening and closing chuck according to the present invention has crowning applied to the intersections of the five surfaces that constitute the outer circumferential surface of the finger protrusions: the top surface, side surface, bottom surface, first end surface, and second end surface. This allows for the reduction of stress concentration when triaxial moments or vertical loads are applied to the fingers.

[0014] Furthermore, the first method for manufacturing the finger according to the present invention combines grinding the side surface of the protruding portion with a first processing tool and grinding the upper and lower surfaces of the protruding portion with a second processing tool to crown the intersections of the five surfaces of the protruding portion, thus enabling the crowning process to be easily carried out in fewer steps.

[0015] Furthermore, the second method for manufacturing the finger according to the present invention uses a single processing tool to simultaneously grind the side surface of the protruding portion and the top and bottom surfaces of the protruding portion, thereby crowning the intersections of the five surfaces of the protruding portion. This makes the crowning process even easier and requires fewer steps. [Brief explanation of the drawing]

[0016] [Figure 1] This is an external perspective view of an opening / closing chuck according to the first embodiment of the present invention. [Figure 2] This is a cross-sectional view of the opening and closing chuck in Figure 1, along the line II-II. [Figure 3] Figure 1 is a front view of the opening and closing zipper. [Figure 4] Figure 1 is a perspective view of the fingers of the opening and closing chuck. [Figure 5] This figure shows a portion of the cross-section of the fingers and body along the VV line in Figure 3. [Figure 6] Figure 6A is an enlarged view of section A in Figure 3, and Figure 6B is an enlarged view of section B in Figure 3. [Figure 7] Figure 4 is a schematic diagram illustrating the method of applying crowning to the finger. [Figure 8] This diagram schematically shows the path taken by the first workpiece when crowning the finger shown in Figure 4. [Figure 9] It is a diagram schematically showing a path for moving the second tool when performing crowning on the fingers in FIG. 4. [Figure 10] It is a front view of the opening and closing chuck according to the second embodiment of the present invention. [Figure 11] FIG. 11A is an enlarged view of part C in FIG. 10, and FIG. 11B is an enlarged view of part D in FIG. 10. [Figure 12] It is a diagram schematically showing a method of performing crowning on the fingers of the opening and closing chuck in FIG. 10. [Figure 13] It is a diagram schematically showing a path for moving the third tool when performing crowning on the fingers of the opening and closing chuck in FIG. 10. [Figure 14] It is a perspective view of the fingers of the opening and closing chuck according to the third embodiment of the present invention. [Figure 15] It is a diagram schematically showing a path for moving the third tool when performing crowning on the fingers in FIG. 14.

Embodiments for Carrying out the Invention

[0017] Regarding the opening and closing chuck and the manufacturing method of its fingers according to the present invention, a plurality of preferred embodiments will be given and described while referring to the accompanying drawings. In the following description, when words regarding the up-down, left-right directions are used, for convenience, they refer to the directions on the drawing and do not limit the actual arrangement of each member.

[0018] (First Embodiment) The opening and closing chuck 10 according to the first embodiment of the present invention will be described while referring to FIGS. 1 to 6. As shown in FIGS. 1 and 2, the opening and closing chuck 10 includes a rectangular parallelepiped body 12 and a pair of fingers 14 that are slidably supported in the longitudinal direction (X direction) of the body 12. An attachment (not shown) for gripping a workpiece is connected to the fingers 14 and used. Reference numeral 14a indicates a screw hole for attachment connection.

[0019] A cylinder chamber 24 is provided in the lower center of the longitudinal direction of the body 12, and above the cylinder chamber 24, a guide groove 22 is provided that extends in the longitudinal direction of the body 12 and opens at both ends to the end faces of the body 12. A piston 26 that can slide in the vertical direction (Z direction) is disposed in the cylinder chamber 24. The cylinder chamber 24 is divided into a first pressure chamber 24a formed below the piston 26 and a second pressure chamber 24b formed above the piston 26. The first pressure chamber 24a is closed by a cap 30.

[0020] A piston rod 28, connected to the piston 26 by a bolt 32, extends further upward through the second pressure chamber 24b. The upper part of the piston rod 28 faces into the guide groove 22 and is a cam portion 28a having a known structure for driving the fingers 14. When air is supplied to the first pressure chamber 24a and the air is discharged from the second pressure chamber 24b, the piston 26 and piston rod 28 move upward, and the pair of fingers 14 slide in a direction away from each other. Conversely, when air is supplied to the second pressure chamber 24b and the air is discharged from the first pressure chamber 24a, the piston 26 and piston rod 28 move downward, and the pair of fingers 14 slide in a direction closer to each other.

[0021] As shown in Figures 3 and 4, each finger 14 is a member with an inverted T-shaped cross-section and has a pair of overhangs 16 and 18 that project laterally from the main body 20 along the entire length of the finger 14 in the longitudinal direction (X direction). The guide groove 22 of the body 12 has an inverted T-shaped cross-section that follows the cross-sectional shape of the finger 14. The finger 14 slides within the guide groove 22 of the body 12.

[0022] To allow the fingers 14 to slide, the upper surfaces 16a, 18a, side surfaces 16b, 18b, and lower surfaces 16c, 18c of each protruding portion 16, 18 face the wall surface of the guide groove 22 with a small gap between them. A larger gap exists between the side surfaces 20a, 20b of the main body portion 20 and the wall surface of the guide groove 22.

[0023] The bottom surface 20c of the main body 20 is substantially flush with the lower surfaces 16c and 18c of the protruding parts 16 and 18. A stepped portion 22a is provided between the wall surface of the guide groove 22 facing the bottom surface 20c of the main body 20 and the wall surface of the guide groove 22 facing the lower surfaces 16c and 18c of the protruding parts 16 and 18 (see Figure 6B).

[0024] The outer circumferential surfaces of each protruding portion 16, 18 of the finger 14 consist of five surfaces: upper surfaces 16a, 18a, side surfaces 16b, 18b, lower surfaces 16c, 18c, first end surfaces (end surfaces in the X1 direction) 16d, 18d, and second end surfaces (end surfaces in the X2 direction) 16e, 18e. The upper surfaces 16a, 18a and lower surfaces 16c, 18c of each protruding portion 16, 18 are perpendicular to the side surfaces 20a, 20b of the main body 20, and also perpendicular to the side surfaces 16b, 18b of the protruding portions 16, 18.

[0025] Crowning is applied to the intersections of the five surfaces mentioned above. Specifically, crowning is applied to the intersections of the top surfaces 16a and 18a with the first end surfaces 16d and 18d, the intersections of the side surfaces 16b and 18b with the first end surfaces 16d and 18d, and the intersections of the bottom surfaces 16c and 18c with the first end surfaces 16d and 18d. Similarly, crowning is applied to the intersections of the top surfaces 16a and 18a with the second end surfaces 16e and 18e, the intersections of the side surfaces 16b and 18b with the second end surfaces 16e and 18e, and the intersections of the bottom surfaces 16c and 18c with the second end surfaces 16e and 18e. In addition, crowning is applied to the intersections of the top surfaces 16a and 18a with the side surfaces 16b and 18b, and the intersections of the bottom surfaces 16c and 18c with the side surfaces 16b and 18b.

[0026] These crownings are designed to create a gap between the protruding portions 16 and 18 of the finger 14 and the wall surface of the guide groove 22, which extends gently from the point of contact between the two. Here, the meaning of "a gap is created that extends gently from the point of contact between the two" is explained further (as is the case in other identical descriptions in this specification). When the finger contacts the body with strong pressure, one or both of the finger and the body undergo elastic deformation, and the boundary between the area of ​​contact and the area of ​​non-contact moves. The crowning is applied to the area including the starting point of this boundary and the expected ending point, and is formed to create a gentle curve throughout the entire area. In other words, it prevents the creation of sharp corners in the area where the finger contacts the body. Figure 5 shows the crowning applied to the intersection of the lower surface 16c and the first end surface 16d of the protruding portion 16. Figure 6A shows the crowning applied to the intersection of the upper surface 16a and the side surface 16b of the protruding portion 16. Figure 6B shows crowning applied to the intersection of the lower surface 16c and the side surface 16b of the protruding portion 16.

[0027] Furthermore, crowning is applied to the guide groove 22 of the body 12 at the intersection of the wall surface facing the upper surfaces 16a and 18a of the protruding parts 16 and 18 and the wall surface facing the side surfaces 20a and 20b of the main body part 20, as well as at the point where the stepped part 22a faces the lower surfaces 16c and 18c of the protruding parts 16 and 18.

[0028] These crownings are designed to create a gap that gently widens continuously from the point of contact between the protruding portions 16 and 18 of the finger 14 and the wall surface of the guide groove 22. Figure 6A shows the crowning applied to the intersection of the wall surface of the guide groove 22 facing the upper surface 16a of the protruding portion 16 and the wall surface of the guide groove 22 facing the side surface 20a of the main body portion 20. Figure 6B shows the crowning applied to the location where the stepped portion 22a faces the lower surface 16c of the protruding portion 16.

[0029] When gripping a workpiece using the opening / closing chuck 10, the fingers 14 are subjected to a pitch moment (moment around the Y axis), as well as a vertical load (Z direction), a lateral load (Y direction), a roll moment (moment around the X axis), and a yaw moment (moment around the Z axis).

[0030] The crowning applied to the intersections of the upper surfaces 16a, 18a and the first end surfaces 16d, 18d, the intersections of the lower surfaces 16c, 18c and the first end surfaces 16d, 18d, the intersections of the upper surfaces 16a, 18a and the second end surfaces 16e, 18e, and the intersections of the lower surfaces 16c, 18c and the second end surfaces 16e, 18e primarily relieves stress concentration when a pitch moment acts on the finger 14. If the radius of curvature of these crownings is R1, and the length of the overhangs 16, 18 in the longitudinal direction (X direction) is L, it is preferable that the value of R1 / L is in the range of 0.1 to 27.

[0031] The crowning applied to the intersections of the upper surfaces 16a, 18a and the side surfaces 16b, 18b, and the intersections of the lower surfaces 16c, 18c and the side surfaces 16b, 18b, primarily relieves stress concentration when a roll moment acts on the fingers 14. If the radius of curvature of these crownings is R2, and the length in the width direction (Y direction) of the protruding portions 16, 18 is W, then it is preferable that the value of R2 / W is in the range of 0.1 to 27. The crowning applied to the guide grooves 22 of the body 12 also relieves stress concentration when a roll moment acts on the fingers 14.

[0032] The crowning applied to the intersections of the side surfaces 16b and 18b with the first end surfaces 16d and 18d, and the intersections of the side surfaces 16b and 18b with the second end surfaces 16e and 18e, primarily relieves stress concentration when a yaw moment acts on the finger 14. If the radius of curvature of these crownings is R3, and the length of the overhangs 16 and 18 in the longitudinal direction is L, then it is preferable that the value of R3 / L is in the range of 0.1 to 27.

[0033] Crowning applied to the intersections of the lower surfaces 16c, 18c and the first end surfaces 16d, 18d, the intersections of the lower surfaces 16c, 18c and the second end surfaces 16e, 18e, and the intersections of the lower surfaces 16c, 18c and the side surfaces 16b, 18b alleviates stress concentration when a vertical load is applied to the finger 14. Crowning applied to the guide groove 22 of the body 12, specifically at the point where the stepped portion 22a faces the lower surfaces 16c, 18c of the protruding portions 16, 18, also alleviates stress concentration when a vertical load is applied to the finger 14.

[0034] Crowning applied to the intersections of the sides 16b, 18b and the first end faces 16d, 18d, the intersections of the sides 16b, 18b and the second end faces 16e, 18e, the intersections of the upper surfaces 16a, 18a and the sides 16b, 18b, and the intersections of the lower surfaces 16c, 18c and the sides 16b, 18b, alleviates stress concentration when a lateral load is applied to the finger 14.

[0035] According to the opening and closing chuck 10 of this embodiment, crowning is applied to the intersections of the five surfaces that constitute the outer circumferential surface of the protruding portions 16 and 18 of the fingers 14: the upper surfaces 16a and 18a, the side surfaces 16b and 18b, the lower surfaces 16c and 18c, the first end surfaces 16d and 18d, and the second end surfaces 16e and 18e. Furthermore, crowning is applied to predetermined locations in the guide groove 22 of the body 12. As a result, stress concentration when a moment around three axes or a vertical load acts on the fingers 14 can be mitigated.

[0036] Next, the manufacturing method of the fingers 14 of the opening / closing chuck 10 will be explained in detail, specifically the method of applying the crowning process to the fingers 14, with reference to Figures 7 to 9.

[0037] This crowning process can perform all of the aforementioned crowning by combining grinding of the side surfaces 16b and 18b of the pair of protruding portions 16 and 18 with grinding of the upper surfaces 16a and 18a and the lower surfaces 16c and 18c of the pair of protruding portions 16 and 18. Grinding of the side surfaces 16b and 18b of the pair of protruding portions 16 and 18 is performed using a first processing tool 34 consisting of a grinding wheel or an end mill, and grinding of the upper surfaces 16a and 18a and the lower surfaces 16c and 18c of the pair of protruding portions 16 and 18 is performed using a second processing tool 36 consisting of a grinding wheel or an end mill.

[0038] As shown in Figure 7, the first working tool 34, which is a rotating body, is made so that the shape of the surface that contacts the workpiece matches the shape of the sides 16b and 18b of the target protrusions 16 and 18, and has crowning portions 34a at both ends. The first working tool 34 is positioned so that its axis is oriented in the Z direction and can be rotated around this axis. The first working tool 34 can also be moved freely in the X and Y directions. For convenience, Figure 7 shows the finger 14 with the shape after crowning.

[0039] The second working tool 36, which is also a rotating body, is made so that the shape of the surface that contacts the workpiece matches the shape of the upper surfaces 16a, 18a and lower surfaces 16c, 18c of the target protruding portions 16, 18, and has a crowning portion 36a at one end. The second working tool 36 is positioned so that its axis is oriented in the Y direction and can be rotated around this axis. Furthermore, the second working tool 36 can be freely moved in the X and Z directions.

[0040] For crowning, first, the fingers 14 are fixed to the clamp base 38 with the pair of protruding parts 16 and 18 facing upward. At this time, the first workpiece 34 is positioned in a retracted position at a predetermined distance from the side surface 16b of one of the protruding parts 16, midway along the longitudinal direction (X direction), and the second workpiece 36 is positioned in a retracted position at a predetermined distance from the lower surface 18c of the other protruding part 18, midway along the longitudinal direction (X direction).

[0041] Next, the first workpiece 34 is moved in the Y2 direction while rotating around its axis, bringing it close to the side surface 16b of one of the protruding portions 16, and bringing it into contact with the side surface 16b with a predetermined pressure. As a result, the side surface 16b of one of the protruding portions 16 is ground at the point of contact with the first workpiece 34. In order to perform this grinding over the entire side surface 16b of one of the protruding portions 16 and the entire side surface 18b of the other protruding portion 18, the first workpiece 34 is moved in a circular motion around the outside of these surfaces.

[0042] Specifically, as schematically shown in Figure 8, the finger is moved in the X1 direction along the side surface 16b of one protruding portion 16 to the vicinity of the first end surface 16d, then moved in the Y2 direction to the vicinity of the side surface 18b of the other protruding portion 18 while increasing the distance from the finger 14, and further moved in the X2 direction along the side surface 18b of the other protruding portion 18 to the vicinity of the second end surface 18e. Next, the finger is moved in the Y1 direction to the vicinity of the side surface 16b of one protruding portion 16 while increasing the distance from the finger 14, and then moved in the X1 direction along the side surface 16b of one protruding portion 16 until it returns to its original position.

[0043] When moving the first processing tool 34, crowning is performed on one protruding portion 16 at the intersection of the side surface 16b and the first end surface 16d. At this intersection, grinding is performed while controlling the amount of movement of the first processing tool 34 in the X1 direction and the Y2 direction. Similarly, crowning is performed on the other protruding portion 18 at the intersection of the side surface 18b and the first end surface 18d. At this intersection, grinding is performed while controlling the amount of movement of the first processing tool 34 in the X2 direction and the Y2 direction. Similarly, to crown the other protruding portion 18 at the intersection of the side surface 18b and the second end surface 18e, grinding is performed at the intersection while controlling the amount of movement of the first workpiece 34 in the X2 direction and the Y1 direction. Similarly, to crown the other protruding portion 16 at the intersection of the side surface 16b and the second end surface 16e, grinding is performed at the intersection while controlling the amount of movement of the first workpiece 34 in the X1 direction and the Y1 direction.

[0044] Once grinding of the sides 16b and 18b of the pair of protruding portions 16 and 18 is completed by rotating the first processing tool 34 once, the rotation of the first processing tool 34 is stopped, and the first processing tool 34 is moved away from the side 16b of one of the protruding portions 16 and retracted.

[0045] Next, the second workpiece 36 is moved in the Z1 direction while rotating around its axis, bringing it closer to the lower surface 18c of the other protruding portion 18, and bringing it into contact with the lower surface 18c with a predetermined pressure. As a result, the lower surface 18c of the other protruding portion 18 at the point of contact with the second workpiece 36 is ground. In order to perform this grinding over the entire lower surface 18c and the entire upper surface 18a of the other protruding portion 18, the second workpiece 36 is moved in a circular motion around the outside of these surfaces.

[0046] Specifically, as schematically shown in Figure 9, the other protruding portion 18 is moved in the X1 direction along the lower surface 18c to the vicinity of the first end surface 18d, then moved in the Z1 direction to the vicinity of the upper surface 18a while maintaining distance from the finger 14, and further moved in the X2 direction along the upper surface 18a to the vicinity of the second end surface 18e. Next, it is moved in the Z2 direction to the vicinity of the lower surface 18c while maintaining distance from the finger 14, and then moved in the X1 direction along the lower surface 18c until it returns to its original position.

[0047] When moving the second workpiece 36, in order to perform crowning at the intersection of the lower surface 18c and the first end surface 18d, grinding is performed at the intersection while controlling the amount of movement of the second workpiece 36 in the X1 direction and the Z1 direction. In order to perform crowning at the intersection of the upper surface 18a and the first end surface 18d, grinding is performed at the intersection while controlling the amount of movement of the second workpiece 36 in the X2 direction and the Z1 direction. Furthermore, in order to perform crowning at the intersection of the upper surface 18a and the second end surface 18e, grinding is performed at the intersection while controlling the amount of movement of the second workpiece 36 in the X2 direction and the Z2 direction. In order to perform crowning at the intersection of the lower surface 18c and the second end surface 18e, grinding is performed at the intersection while controlling the amount of movement of the second workpiece 36 in the X1 direction and the Z2 direction.

[0048] Once grinding of the upper surface 18a and lower surface 18c of the other protruding portion 18 is completed by rotating the second processing tool 36 once around the other protruding portion 18, the rotation of the second processing tool 36 is stopped, and the second processing tool 36 is moved away from the lower surface 18c of the other protruding portion 18 and temporarily retracted.

[0049] Next, the clamp base 38 is rotated 180 degrees in the horizontal plane so that the second workpiece 36 is positioned opposite the lower surface 16c of one of the protruding portions 16. Then, the second workpiece 36 is moved in the Z1 direction while rotating it again around its axis, bringing it closer to the lower surface 16c of one of the protruding portions 16, and bringing it into contact with the lower surface 16c with a predetermined pressure. As a result, the lower surface 16c of one of the protruding portions 16 at the point of contact with the second workpiece 36 is ground. In order to perform this grinding over the entire upper surface 16a and the entire lower surface 16c of one of the protruding portions 16, the second workpiece 36 is moved in a circular motion around the outside of these surfaces.

[0050] Specifically, the protruding portion 16 is moved in the X2 direction along the lower surface 16c to the vicinity of the second end surface 16e, then moved in the Z1 direction to the vicinity of the upper surface 16a while maintaining distance from the finger 14, and further moved in the X1 direction along the upper surface 16a to the vicinity of the first end surface 16d. Next, it is moved in the Z2 direction to the vicinity of the lower surface 16c while maintaining distance from the finger 14, and then moved in the X2 direction along the lower surface 16c until it returns to its original position.

[0051] When the second processing tool 36 is moved, the amount of movement in the X direction and the amount of movement in the Z direction are controlled at the intersection of the lower surface 16c and the second end surface 16e, the intersection of the upper surface 16a and the second end surface 16e, the intersection of the upper surface 16a and the first end surface 16d, and the intersection of the lower surface 16c and the first end surface 16d, similar to the case of the other protruding portion 18.

[0052] By rotating the second workpiece 36 around one of the protruding portions 16, grinding of the upper surface 16a and lower surface 16c of one of the protruding portions 16 is completed. Once this is done, the rotation of the second workpiece 36 is stopped, and the second workpiece 36 is moved away from the lower surface 16c of the protruding portion 16. Through these steps, crowning can be applied to the intersections of the five surfaces that make up the outer circumferential surfaces of the pair of protruding portions 16 and 18 of the finger 14.

[0053] (Second Embodiment) Next, a method for manufacturing the opening / closing chuck 40 and its fingers 42 according to a second embodiment of the present invention will be described with reference to Figures 10 to 13. The opening / closing chuck 40 according to the second embodiment differs from the opening / closing chuck 10 according to the first embodiment in the shape of the pair of protruding portions on the fingers and the shape of the guide grooves provided on the body.

[0054] As shown in Figures 10 and 12, the finger 42 has a pair of trapezoidal protrusions 44 and 46 that project laterally from the main body 48 along its entire longitudinal length. The upper surfaces 44a and 46a and the lower surfaces 44c and 46c of each protrusion 44 and 46 are tapered surfaces that become closer to each other as they approach the side surfaces 44b and 46b. The guide groove 50 of the body 12 has a cross-sectional shape that follows the cross-sectional shape of the finger 42. In order to allow the finger 42 to slide, the upper surfaces 44a and 46a, the side surfaces 44b and 46b, and the lower surfaces 44c and 46c of each protrusion 44 and 46 face the wall surface of the guide groove 50 with a small gap between them, and the bottom surface 48c of the main body 48 also faces the wall surface of the guide groove 50 with a small gap between it and the wall surface of the guide groove 50.

[0055] Crowning is applied to the intersections of the five surfaces that constitute the outer circumferential surface of each protruding portion 44, 46: the upper surfaces 44a, 46a, the side surfaces 44b, 46b, the lower surfaces 44c, 46c, the first end surfaces 44d, 46d, and the second end surfaces 44e, 46e. Specifically, crowning is applied to the intersections of the upper surfaces 44a, 46a and the first end surfaces 44d, 46d, the intersections of the side surfaces 44b, 46b and the first end surfaces 44d, 46d, and the intersections of the lower surfaces 44c, 46c and the first end surfaces 44d, 46d. Similarly, crowning is applied to the intersections of the upper surfaces 44a, 46a and the second end surfaces 44e, 46e, the intersections of the side surfaces 44b, 46b and the second end surfaces 44e, 46e, and the intersections of the lower surfaces 44c, 46c and the second end surfaces 44e, 46e. Crowning is also applied to the intersections of the upper surfaces 44a, 46a and the side surfaces 44b, 46b, and the intersections of the lower surfaces 44c, 46c and the side surfaces 44b, 46b.

[0056] These crownings are designed to create a gap between the protruding portions 44 and 46 of the finger 42 and the wall surface of the guide groove 50, which extends gently and continuously from the point of contact between them. Figure 11A shows the crowning applied to the intersection of the upper surface 44a and the side surface 44b of the protruding portion 44. Figure 11B shows the crowning applied to the intersection of the lower surface 44c and the side surface 44b of the protruding portion 44.

[0057] Furthermore, crowning is applied to the guide groove 50 of the body 12 at the intersection of the wall surface facing the upper surfaces 44a and 46a of the protruding parts 44 and 46 and the wall surface facing the side surfaces 48a and 48b of the main body part 48, as well as at the point where the stepped part 50a faces the lower surfaces 44c and 46c of the protruding parts 44 and 46.

[0058] These crownings are designed to create a gap that gently widens from the point of contact between the protruding portions 44 and 46 of the finger 42 and the wall surface of the guide groove 50. Figure 11A shows the crowning applied to the intersection of the wall surface of the guide groove 50 facing the upper surface 44a of the protruding portion 44 and the wall surface of the guide groove 50 facing the side surface 48a of the main body portion 48. Figure 11B shows the crowning applied to the point where the stepped portion 50a faces the lower surface 44c of the protruding portion 44.

[0059] According to the opening and closing chuck 40 of this embodiment, crowning is applied to the intersections of the five surfaces that constitute the outer circumferential surface of the protruding portions 44 and 46 of the fingers 42: the upper surfaces 44a and 46a, the side surfaces 44b and 46b, the lower surfaces 44c and 46c, the first end surfaces 44d and 46d, and the second end surfaces 44e and 46e. Furthermore, crowning is applied to predetermined locations in the guide groove 50 of the body 12. This makes it possible to mitigate stress concentration when a moment or vertical load is applied to the fingers around three axes.

[0060] Next, the method for applying the crowning described above to the finger 42 (crowning process) will be explained with reference to Figures 12 and 13. This crowning process uses a third processing tool 52 (a single processing tool) consisting of a grinding wheel or end mill to simultaneously grind the sides 44b and 46b of the pair of protruding portions 44 and 46, and the upper surfaces 44a and 46a and lower surfaces 44c and 46c of the pair of protruding portions 44 and 46, thereby applying all of the aforementioned crowning.

[0061] As shown in Figure 12, the third working tool 52, which is a rotating body, is manufactured so that the shape of the surface that contacts the workpiece matches the shape of the upper surfaces 44a, 46a, side surfaces 44b, 46b, and lower surfaces 44c, 46c of the target protrusions 44, 46. The third working tool 52 is positioned so that its axis is oriented in the Z direction and can be rotated around this axis. Furthermore, the third working tool 52 can be freely moved in the X and Y directions.

[0062] The third processing tool 52 is provided with a first crowning section 52a and a second crowning section 52b. The first crowning section 52a is for applying crowning to the intersection of the upper surfaces 44a, 46a and the side surfaces 44b, 46b of the protruding sections 44, 46, and the second crowning section 52b is for applying crowning to the intersection of the lower surfaces 44c, 46c and the side surfaces 44b, 46b of the protruding sections 44, 46.

[0063] For crowning, first, the fingers 42 are fixed to the clamp base 38 with the pair of protruding portions 44 and 46 facing upwards. At this time, the third working tool 52 is positioned in the middle of the longitudinal direction (X direction) of one of the protruding portions 44, facing the said protruding portion 44.

[0064] Next, the third workpiece 52 is moved in the Y2 direction while rotating around its axis, bringing it closer to one of the protruding portions 44, and bringing it into contact with its upper surface 44a, side surface 44b, and lower surface 44c with a predetermined pressure. As a result, the upper surface 44a, side surface 44b, and lower surface 44c of one of the protruding portions 44 at the point of contact with the third workpiece 52 are simultaneously ground. In order to perform this grinding over the entire protruding portion 44 and the entire protruding portion 46, the third workpiece 52 is moved in a circular motion around the outside of these portions.

[0065] Specifically, as schematically shown in Figure 13, the finger is moved in the X1 direction along the side surface 44b of one of the protruding portions 44 to the vicinity of the first end surface 44d, then moved in the Y2 direction to the vicinity of the side surface 46b of the other protruding portion 46 while maintaining distance from the finger 42, and further moved in the X2 direction along the side surface 46b of the other protruding portion 46 to the vicinity of the second end surface 46e. Next, the finger is moved in the Y1 direction to the vicinity of the side surface 44b of one of the protruding portions 44 while maintaining distance from the finger 42, and then moved in the X1 direction along the side surface 44b of one of the protruding portions 44 until it returns to its original position.

[0066] When the third processing tool 52 moves, crowning is performed on one of the protruding portions 44 at the intersection of the upper surface 44a and the first end surface 44d, the intersection of the side surface 44b and the first end surface 44d, and the intersection of the lower surface 44c and the first end surface 44d. At these intersections, grinding is performed while controlling the amount of movement of the third processing tool 52 in the X1 direction and the Y2 direction. Similarly, crowning is performed on the other protruding portion 46 at the intersection of the upper surface 46a and the first end surface 46d, the intersection of the side surface 46b and the first end surface 46d, and the intersection of the lower surface 46c and the first end surface 46d. At these intersections, grinding is performed while controlling the amount of movement of the third processing tool 52 in the X2 direction and the Y2 direction.

[0067] Furthermore, for the other protruding portion 46, crowning is applied to the intersection of the upper surface 46a and the second end surface 46e, the intersection of the side surface 46b and the second end surface 46e, and the intersection of the lower surface 46c and the second end surface 46e. At these intersections, grinding is performed while controlling the amount of movement of the third workpiece 52 in the X2 direction and the Y1 direction to refine the grinding. Similarly, for the other protruding portion 44, crowning is applied to the intersection of the upper surface 44a and the second end surface 44e, the intersection of the side surface 44b and the second end surface 44e, and the intersection of the lower surface 44c and the second end surface 44e. At these intersections, grinding is performed while controlling the amount of movement of the third workpiece 52 in the X1 direction and the Y1 direction to refine the grinding.

[0068] In this way, by simply rotating the third processing tool 52 once, crowning can be applied to the intersections of the five surfaces that make up the outer circumferential surfaces of the pair of protruding portions 44 and 46 of the finger 42.

[0069] (Third embodiment) Next, the fingers 62 of the opening / closing chuck according to the third embodiment of the present invention and a method for manufacturing the same will be described with reference to Figures 14 and 15. The fingers 62 according to the third embodiment differ from the fingers 42 of the opening / closing chuck according to the second embodiment in that each protruding portion is provided with a recess and a grease reservoir.

[0070] As shown in Figure 14, a recess 72 is provided in the longitudinal center of the upper surface 64a, side surface 64b, and lower surface 64c of one of the protruding portions 64, and crowning regions CR1 and CR2 are provided at both ends of the recess 72. A grease reservoir 70 is provided opening to the bottom surface of the recess 72 formed on the upper surface 64a. A grease reservoir 70 is also provided on the other protruding portion 66 with a similar configuration. The grease stored in the grease reservoir 70 is supplied to the sliding surfaces of each protruding portion 64, 66, maintaining the lubrication function.

[0071] Since the grease reservoir 70 opens to the bottom surface of the recess 72, its edge does not come into contact with the wall surface of the guide groove, preventing stress concentration. Furthermore, since the recess 72 is connected to the sliding surfaces (surfaces that come into contact with the wall surface of the guide groove) on the upper surface 64a, side surface 64b, and lower surface 64c via the crowned areas CR1 and CR2, the presence of the recess 72 does not cause stress concentration between it and the guide groove.

[0072] Crowning is applied to the intersections of the five surfaces that constitute the outer circumferential surface of each protruding portion 64, 66: the upper surfaces 64a, 66a, the side surfaces 64b, 66b, the lower surfaces 64c, 66c, the first end surfaces 64d, 66d, and the second end surfaces 64e, 66e. In addition, crowning is applied to the guide grooves of the body 12 at the intersections of the wall surfaces facing the upper surfaces 64a, 66a of the protruding portions 64, 66 and the wall surfaces facing the side surfaces 68a, 68b of the main body portion 68. Crowning is also applied to the stepped portions of the guide grooves where they face the lower surfaces 64c, 66c of the protruding portions 64, 66.

[0073] Next, the method for applying the crowning described above to the finger 62 (crowning process) will be explained with reference to Figure 15. This crowning process uses the same third processing tool (single processing tool) 52 as in the second embodiment to simultaneously grind the side surfaces 64b, 66b of the pair of protruding portions 64, 66 and the upper surfaces 64a, 66a and lower surfaces 64c, 66c of the pair of protruding portions 64, 66, thereby applying all of the aforementioned crowning.

[0074] While rotating the third workpiece 52 around its axis, it is brought into contact with the upper surface 64a, side surface 64b, and lower surface 64c of one of the protruding portions 64 at a predetermined position in the longitudinal direction (X direction), and these surfaces are ground simultaneously. In order to perform this grinding over the entire protruding portion 64 and the entire protruding portion 66 of the other, the third workpiece 52 is moved in a circular motion around the outside of these portions.

[0075] As the third processing tool 52 moves, grinding is performed at the intersection of the side surface 64b etc. of one protruding portion 64 and the first end face 64d, the intersection of the side surface 66b etc. of the other protruding portion 66 and the first end face 66d, the intersection of the side surface 66b etc. of the other protruding portion 66 and the second end face 66e, and the intersection of the side surface 64b etc. of one protruding portion 64 and the second end face 64e, while controlling the amount of movement of the third processing tool 52 in the X direction and the amount of movement in the Y direction, as in the second embodiment.

[0076] Furthermore, for one of the protruding portions 64, in order to form crowning regions CR1, CR2 and recesses 72, grinding is performed near the longitudinal center of the one protruding portion 64 while controlling the amount of movement of the third workpiece 52 in the Y1 direction or the Y2 direction. Similarly, grinding is performed near the longitudinal center of the other protruding portion 66 while controlling the amount of movement of the third workpiece 52 in the Y1 direction or the Y2 direction.

[0077] In this way, by simply rotating the third processing tool 52 once, crowning can be applied to the intersections of the five surfaces that make up the outer circumferential surfaces of the pair of protruding portions 64 and 66, and crowning regions CR1 and CR2 and recesses 72 can be formed on the pair of protruding portions 64 and 66.

[0078] The method for manufacturing the opening and closing chuck and its fingers according to the present invention is not limited to the embodiments described above, and various configurations can be adopted without departing from the spirit of the present invention. [Explanation of symbols]

[0079] 10, 40... Zipper opening / closing; 12... Body 14, 42, 62... fingers 16, 18, 44, 46, 64, 66...Protrusion 16a, 18a, 44a, 46a, 64a, 66a...Top surface 16b, 18b, 44b, 46b, 64b, 66b… side view 16c, 18c, 44c, 46c, 64c, 66c...Bottom side 16d, 18d, 44d, 46d, 64d, 66d...first end surface 16e, 18e, 44e, 46e, 64e, 66e...2nd end surface 20, 48, 68... Main body 20a, 20b, 48a, 48b, 68a, 68b... Side view of the main body 20c, 48c...Bottom of the main body 22, 50... Guide grooves 22a, 50a... Stepped sections 34...First processing tool 36...Second processing tool 52...Third cutting tool (single cutting tool) 70...Grease reservoir 72...Recessed area CR1, CR2...Crowning area

Claims

1. A method for manufacturing a pair of fingers that slide within a guide groove of the body of an opening and closing chuck and are supported to slide freely in directions toward and toward each other, The finger has a pair of protrusions that project laterally from the main body, and the outer circumferential surface of the protrusions consists of five surfaces: an upper surface, a side surface, a lower surface, a first end surface, and a second end surface, and the upper surface and the lower surface are perpendicular to the side surface. A method for manufacturing a finger, comprising the step of applying crowning to the intersections of the five surfaces by combining grinding the side surface with a first processing tool and grinding the top surface and the bottom surface with a second processing tool, wherein the crowning forms a gap between the protruding portion and the wall surface of the guide groove that extends continuously from the contact point between the two.

2. A method for manufacturing a pair of fingers that slide within a guide groove of the body of an opening and closing chuck and are supported to slide freely in directions toward and toward each other, The finger has a pair of protrusions that project laterally from the main body, and the outer circumferential surface of the protrusions consists of five surfaces: an upper surface, a side surface, a lower surface, a first end surface, and a second end surface, and the upper surface and the lower surface are tapered surfaces that become closer to each other as they approach the side surface. A method for manufacturing a finger, comprising the step of simultaneously grinding the side surface and the top and bottom surfaces using a single processing tool, thereby crowning the intersections of the five surfaces, wherein the crowning forms a gap between the protruding portion and the wall surface of the guide groove that extends continuously from the contact point between the two.

3. A method for manufacturing a finger according to claim 2, A recess is provided in the longitudinal center of the upper surface, the side surface, and the lower surface, crowning regions are provided at both ends of the recess, and a grease reservoir is provided that opens to the bottom surface of the recess on the upper surface. A method for manufacturing a finger, wherein the crowning region is crowned by the above-mentioned step.

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