Dimension measuring apparatus

Abstract

To provide a dimension measuring device for suppressing the resonance of a finger and improving the dimension measuring accuracy of a work by changing the natural frequency of the finger by a low-cost and simple method.SOLUTION: A dimension measuring device 60 includes a gauge head 300 abutting on a workpiece W, a long member 31 supporting the gauge head 300 on one end side and swingably supported by a body on the other end side, and an axial force adjusting means 30 for adjusting the axial force of the long member 31.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present disclosure relates to a dimension measuring device for measuring the shape or dimensions of a workpiece being processed, and in particular to a dimension measuring device having a means for changing the natural frequency of a finger used in the dimension measuring device. [Background technology]

[0002] Conventionally, a dimension measuring device has been known in which a finger with a contact at the tip is attached so as to be able to swing freely in the measurement direction and the retraction direction, and the finger is swung in the measurement direction to bring the contact into contact with the outer surface of the workpiece, and an electrical signal based on the amount of displacement is detected by a differential transformer to measure the outer diameter of the workpiece (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2001-027502 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the conventional dimension measuring device described in Patent Document 1, when the finger resonates at its natural frequency, the vibration is transmitted to the contact at the tip of the finger, causing the tip of the contact to vibrate in the measurement direction according to the natural frequency of the finger. As a result, the strength of the contact varies between the tip of the contact and the outer surface of the workpiece, and the amount of finger displacement changes according to the vibration of the finger, resulting in the problem that the outer diameter of the workpiece cannot be measured accurately.

[0005] To solve this problem, conventionally, when resonance occurs in the fingers, a mass (weight) is added to the base of the finger or parts in the finger area are replaced to avoid the resonance problem.

[0006] However, while the method of adding a mass to the finger can suppress the resonance of the finger, the moment of inertia increases as the mass increases, which causes the measurement of the displacement amount using a differential transformer to become unstable, resulting in a problem of reduced accuracy in measuring the outer diameter dimensions of the workpiece.

[0007] The present disclosure has been made in consideration of the problems with conventional dimension measuring devices described above, and aims to suppress finger resonance and improve the accuracy of workpiece dimension measurement by changing the natural frequency of the finger in a low-cost and simple manner without sacrificing measurement accuracy. [Means for solving the problem]

[0008] The present disclosure has been made in consideration of the above problems, and is characterized by comprising a measuring probe that contacts a workpiece, an elongated member that supports the measuring probe at one end and is supported by a main body at the other end so as to be swingable, and axial force adjustment means that adjusts the axial force of the elongated member. [Effects of the Invention]

[0009] According to the present disclosure, by changing the natural frequency of the finger using a low-cost and simple method, resonance of the finger is suppressed and the accuracy of measuring the dimensions of the workpiece is improved. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a schematic perspective view showing an example of use of a dimension measurement system including a dimension measurement device according to an embodiment. [Figure 2] FIG. 2 is a partial cross-sectional schematic view of a dimension measuring device according to an embodiment. [Figure 3] FIG. 3 is a schematic cross-sectional view taken along dashed line AA of the dimension measuring device according to the embodiment. [Figure 4A] FIG. 4A is a cross-sectional view showing a first modified example of the finger shown in FIG. [Figure 4B] FIG. 4B is a cross-sectional view showing a first modification of the finger shown in FIG. [Figure 5] FIG. 5 is a cross-sectional view showing a second modified example applied to a lever shaft. [Figure 6] FIG. 6 is a cross-sectional view showing a third modification of the finger shown in FIG. [Figure 7] FIG. 7 is a cross-sectional view showing another embodiment applied to a conveyor. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, embodiments of a dimension measuring device according to the present disclosure will be described with reference to the drawings. Note that the same reference numerals are used to designate the same components throughout the drawings. Furthermore, the embodiments shown in the drawings are merely examples and do not limit the present disclosure in any way. Furthermore, the embodiments and their variations described below can be combined in any manner, and such combinations are within the scope of the present disclosure.

[0012] FIG. 1 is a schematic perspective view showing an example of use of a dimension measurement system including a dimension measurement device according to an embodiment. The dimension measurement system 1 includes a pair of dimension measurement devices 60 that measure the outer diameter of a workpiece W and a control device 20 that controls the operation of the dimension measurement devices 60 and processes signals from the dimension measurement devices 60. In this example, for convenience of explanation, the dimension measurement devices 60 are shown as a pair separated in the Z-axis direction, but this is not limited to this and they may also be configured as an integrated unit. The workpiece W may be, but is not limited to, a CNC (Computer Numerical Control) machined part or the like. The workpiece W may be stationary or rotating about its central axis. The control device 20 and a compressed air source (not shown) may be attached to a general-purpose measuring head (not shown). Note that the dimension measurement device 60 in this example is a device that measures the outer diameter of the workpiece W, but the parameter (dimension) measured is not limited to the outer diameter. It may also be the inner diameter of the workpiece W as long as it is measured by contacting a measuring probe. The dimension measuring device may also be for plane measurement (for measuring height, thickness, etc.), and may be incorporated into a back grinder in the semiconductor manufacturing process.

[0013] The control device 20 is connected by wire or wirelessly to the operator's work terminal 10, the compressed air source, and the differential transformer 180 included in the dimension measuring device 60. The dimension measuring device 60 has a probe 300 attached to the tip end of a long finger 234 extending in the Y-axis direction (described later), and a differential transformer 180 attached to the rear end, opposite the probe 300. In response to a command issued through the operator's work terminal 10, the control device 20 controls the operation of the compressed air source so that compressed air from the compressed air source flows into a retraction mechanism of the dimension measuring device 60. The tip of the probe 300 contacts the surface of the workpiece W due to the action of the retraction mechanism (described later). A signal based on the displacement of the probe 300 from a predetermined reference point is amplified by the differential transformer 180 and transmitted to the control device 20 by wire or wirelessly. The control device 20 accurately calculates the outer diameter of the workpiece W based on the signal received from the differential transformer 180 and displays the calculated value on the operator's work terminal 10.

[0014] FIG. 2 is a partial cross-sectional schematic diagram of a dimension measuring device 60 according to an embodiment. The dimension measuring device 60 includes a substantially rectangular parallelepiped case member 190, and a retraction mechanism 100, which is a pneumatic cylinder, and a differential transformer 180 housed therein. A lever shaft 132, which is connected to a measuring element 300 via a finger 234, extends laterally (in the Y-axis direction) from the case member 190. A bellows 220, which enables precession of the lever shaft 132, is disposed between the case member 190 and the lever shaft 132. Engagement portions 222 and 224 are formed at both ends of the bellows 220. A pivot shaft 140 is disposed within the case member 190 in a direction substantially perpendicular to the lever shaft 132, and the pivot shaft 140 is fitted into a through-hole provided in a support base (main body) 142 disposed in the longitudinal middle of the lever shaft 132. Therefore, the lever shaft 132 can swing around the swing shaft 140 .

[0015] One side of case member 190 has an opening, and one end of bellows 220 described above is held airtight in the opening by locking portion 222. The other end of bellows 220 is airtightly connected to end 132b of lever shaft 132 by locking portion 224. End 132b of lever shaft 132 on the attachment side of bellows 220 is coupled to finger 234 via position fine adjustment device 237 so that its position can be finely adjusted.

[0016] The finger 234 is provided with a means for changing the natural frequency (described later), thereby suppressing resonance of the finger 234. The position fine adjustment device 237 includes a stay 231, made of, for example, a metal, with a substantially T-shaped cross section, connected to the end 132b of the lever shaft 132; a plate-shaped elastic member 232 having an end surface contacting the end surface of the stay 231; a plate-shaped rigid member 233 sandwiching the plate-shaped elastic member 232 together with the stay 231; and a connecting member 235 having an end surface contacting the end surface of the plate-shaped rigid member 233 and connecting the opposite end surface to the end surface of the end of the finger 234. The plate-shaped elastic member 232 may be, but is not limited to, a rubber sheet. The plate-shaped rigid member 233 may be, but is not limited to, a metal, ceramic, or resin sheet. The connecting member 235 may be a rectangular parallelepiped or cylindrical member made of metal, ceramic, or rubber.

[0017] The stay 231, the plate-shaped elastic member 232, the plate-shaped rigid member 233, and the connecting member 235 have a plurality of through-holes that penetrate in the Y-axis direction and are rotationally symmetrical on the XZ plane, and the respective through-holes are aligned with one another. Therefore, the stay 231, the plate-shaped elastic member 232, the plate-shaped rigid member 233, and the connecting member 235 can be fixed to one another by inserting bolts through the through-holes and fastening them with nuts. In this way, a multi-layer structure is formed by stacking a plurality of members with different elastic moduli, and the relative position of the contact portion 240 at the tip of the probe 300 with respect to the lever shaft 132 can be finely adjusted by adjusting the tightness of each bolt that is arranged rotationally symmetrically.

[0018] The fine position adjustment in the Y-axis direction can be performed by adjusting the position of the finger 234 in the Y-axis direction using a position adjustment device (not shown) disposed between the lever shaft 132 and the stay 231. The position adjustment device 237 not only finely adjusts the position of the tip of the probe 300 relative to the lever shaft 132, but also has the function of adjusting distortion of the finger 234 in the longitudinal axis direction (Y-axis direction), as will be described later. That is, as will be described later, distortion of the finger 234 when a force is applied in a direction perpendicular to the longitudinal axis direction (Y-axis direction) of the finger 234 can be finely adjusted by the position adjustment device 237 so that there is no apparent distortion. As a result, highly accurate dimensional measurements are ensured. The configuration of the position adjustment device 237 is not limited to that described above.

[0019] A probe holder 236 for holding the probe 300 is attached to the tip of the finger 234 on the side opposite to the side connected to the lever shaft 132. By adjusting a set screw 238 that engages with the probe holder 236, the position of the contactor portion 240 at the tip of the probe 300 can be adjusted in the vertical direction (Z-axis direction) in Fig. 2. When measuring the outer diameter as shown in Fig. 1, the upper contactor portion 240 of this example is pressed downward, and the lower contactor portion 240 of this example is pressed upward, thereby clamping the workpiece W and measuring the outer diameter.

[0020] The upper dimension measuring device 60 will be described below, but the lower dimension measuring device 60 has the same configuration and functions as the upper dimension measuring device 60 except that it is upside down.

[0021] To press the contact portion 240 downward, a tension spring 146 is disposed inside the case member 190 on the opposite side 132a of the lever shaft 132 from the holder 142 toward the measuring element. One end of the tension spring 146 is engaged with a support shaft 148 protruding inside the case member 190, and the other end of the tension spring 146 is engaged with a locking member 134 provided at the longitudinal middle of the lever shaft 132. Therefore, the tension spring 146 acts to attract the lever shaft 132 at that position, causing the lever shaft 132 to swing around the swing shaft 140 and then pressing the finger 234 downward. This enables measurement. The differential transformer 180, tension spring 146, and swing shaft 140 constitute a swinging means.

[0022] A displacement shaft 182 is attached perpendicular to the lever shaft 132 near the end of the lever shaft 132 on the side 132a opposite to the probe, and a coil 184 is wound around the displacement shaft 182 to form a differential transformer 180. A signal from the differential transformer 180 is input to a terminal processing unit 186, where it is processed, and then transmitted to the control device 20 (see FIG. 1).

[0023] When the measurement is completed or when preparation for the measurement is being made, the contactor portion 240 is moved away from the workpiece W to protect both the contactor portion 240 and the workpiece W. For this reason, a retraction mechanism 100, which is a pneumatic cylinder, is disposed in the longitudinal direction of the lever shaft 132, between the tension spring 146 and the differential transformer 180.

[0024] The retraction mechanism 100 includes a cap-shaped cylinder 110, a piston 120 that is slidable within the cylinder 110 and has a piston head 116 and a piston rod 118, a cylinder base 112 that is located below the cylinder 110 and in sliding contact with the lower part of the piston rod 118, and a coil spring 122 that is wound around the piston rod 118 and is disposed between the piston head 116 and the cylinder base 112. One end (upper side) of the piston rod 118 is housed within the cylinder 110, and the other end (lower side) extends downward from the cylinder base 112. An abutment portion 136 that is the lower end of the piston rod 118 can abut against a lever shaft 132.

[0025] Next, the operation of the retraction mechanism 100 will be described. During measurement, pressurized air from the compressed air source is not introduced into the space 108 formed between the cylinder 110 and the piston head 116, and the pressure in the space 108 becomes approximately the same as the pressure in the space 106 of the piston head, which is connected to the outside atmosphere (approximately atmospheric pressure). As a result, the restoring force (elastic force) of the coil spring 122 becomes dominant, and the piston rod 118 is pulled upward. At this time, the lever shaft 132, which had been in contact with the piston rod 118, rotates clockwise around the swing shaft 140 by the tension spring 146, and the probe 300, located at the tip of the finger 234 connected to the tip of the lever shaft 132, moves downward. The downward movement stops as soon as the probe 300 comes into contact with the workpiece W, and the amount of displacement between this position and the reference point is measured by the differential transformer 180, which is provided at the end of the lever shaft 132 opposite the probe 300.

[0026] On the other hand, when measurement is not being performed, pressurized air is introduced from a compressed air source into the space 108 formed between the cylinder 110 and the piston head 116, urging the coil spring 122 in the compression direction, causing the piston rod 118 to move downward against the elastic force of the coil spring 122. The abutting portion 136 of the piston rod 118 abuts against the lever shaft 132, pushing the lever shaft 132 downward and causing it to rotate counterclockwise around the swing shaft 140 in the figure, causing the probe 300 located at the tip of the finger 234 connected to the tip of the lever shaft 132 to move upward. In this way, the contact portion 240 moves away from the workpiece W. When the lever shaft 132 has rotated to a position where the force applied by the abutting portion 136 of the piston rod 118 to the lever shaft 132 and the elastic force of the tension spring 146 are balanced, the position of the probe 300 in the Z-axis direction is maintained.

[0027] 3 is a schematic cross-sectional view of the dimension measuring device according to the embodiment taken along the dashed line A-A. For convenience of explanation, the measuring element 300 is indicated by an arrow.

[0028] The finger 234 is provided with an elongated member 31 and an axial force adjusting means 30 that adjusts the axial force of the elongated member 31 to convert the natural vibration. The elongated member 31 includes a rod member 32, which is an inserted member extending along the longitudinal direction (Y-axis direction) of the finger 234, and an outer cylinder 35 that houses the rod member 32. The rod member 32 includes a shaft portion 33 with a threaded portion 33a and a large-diameter support portion 34 fixed to the shaft portion 33. The large-diameter support portion 34 of the rod member 32 is exposed to the outside at the other end of the outer cylinder 35. A general-purpose bolt can be used as the rod member 32. The probe 300 may be fixed to the rod member 32. The outer cylinder 35 has an internal space 35a. In this embodiment, the outer cylinder 35 is cylindrical, but is not limited thereto and may be, for example, rectangular.

[0029] The axial force adjusting means 30, which adjusts the axial force of the long member 31 to convert the natural frequency, has a nut 36, which is a fastening member, and this nut 36 is screwed into a threaded portion 33a exposed to the outside from one end side of the outer cylinder 35. The nut 36 sandwiches the outer cylinder 35 between itself and the large diameter support portion 34 of the rod member 32, and the fastening force of the nut 36 changes the fixed position of one end of the rod member 32, thereby adjusting the tensile force, which is the axial force of the rod member 32. As a result, the natural frequency of the rod member 32 is converted.

[0030] In other words, when the nut 36 is rotated in the tightening direction, a gradually increasing compressive force is applied to the outer tube 35 in accordance with the thread pitch, and a tensile force is applied as a reaction to this force on the rod member 32. Conversely, when the nut 36 is rotated in the loosening direction, the compressive force on the outer tube 35 gradually decreases in accordance with the thread pitch, and a tensile force on the rod member 32 is weakened as a reaction to this force.

[0031] In this way, by varying the fixed position (thread engagement position) of the nut 36, the tensile force acting on the rod member 32 can be adjusted. In this embodiment, the axial force adjustment means 30 has the nut 36 as a fastening member that fixes one end of the insertion member (rod member 32). However, the configuration of the axial force adjustment means 30 is not limited to the above. The fastening member only needs to be able to adjust the amount of protrusion of one end of the insertion member from the outer tube 35. In other words, the fastening member only needs to be able to fix the insertion member that has protruded a predetermined amount from the outer tube 35 in that position. Known members such as a collet nut, a shaft collar, a cotter pin, and a snap ring can be used as the fastening member.

[0032] In this embodiment, one end of the insertion member (rod member 32) is fixed to the outer tube 35 by a fastening member (nut 36). However, the fastening member may be configured to adjust the amount of protrusion of the insertion member at both ends of the outer tube 35 and fix it. Specifically, instead of the large diameter support portion 34, another threaded portion may be provided at the end of the rod member 32, and it may be fixed to the outer tube 35 by another nut.

[0033] In the above configuration, assume that measurement is started by the dimension measuring device 60, and an external force (including external vibration) causes the structure including the fingers 234 to resonate at its natural frequency, resulting in a malfunction such as a sudden jump in the measured value.

[0034] The measurer varies the fastening state of the nut 36, which is the axial force adjusting means 30, and varies the tensile force of the rod member 32 as described above. This varies the natural frequency of the entire structure including the fingers 234. If the resonant vibration is not corrected even with this natural frequency, the measurer again varies the tensile force acting on the rod member 32. This change in the tensile force of the rod member 32 is repeated until the structure including the fingers 234 no longer resonates. This makes it possible to eliminate problems caused by the resonant vibration of the structure including the fingers 234.

[0035] Furthermore, the natural frequency of the structure including the fingers 234 can be changed by the nuts 36, which are the axial force adjusting means 30 provided on the fingers 234. In other words, since there is no need to rely on expensive equipment such as vibration sensors, the natural frequency of the fingers 234 can be changed using a low-cost and simple method, thereby suppressing resonance of the fingers 234 and improving the dimensional measurement accuracy of the workpiece W.

[0036] Furthermore, since the natural frequency can be adjusted as described above, it can be changed to any natural frequency. If a filter is applied to this natural frequency, it is possible to reliably prevent resonant vibration.

[0037] In this embodiment, since only a tensile force acts on the rod member 32, it is sufficient that the large diameter support portion 34 of the rod member 32 is rotatably supported on one end of the outer tube 35, and it is not necessary to fix it non-rotatably. However, if the large diameter support portion 34 of the rod member 32 is fixed non-rotatably on one end of the outer tube 35, the nut 36 can be rotated without the rod member 32 spinning freely, improving the ease of adjustment work.

[0038] In this embodiment, a nut 36 disposed on the outside of the other end of the outer tube 35 is threaded onto the threaded portion 33a of the rod member 32, and the outer tube 35 is sandwiched between the large diameter support portion 34 of the rod member 32 and the nut 36. As a variation of this, a threaded hole may be formed on the inner surface of the other end of the outer tube 35, and the threaded portion 33a of the rod member 32 may be threaded into this threaded hole. However, if the threaded portion 33a of the rod member 32 is threaded into the threaded hole of the outer tube 35, it is necessary to provide the large diameter support portion 34 so that it can rotate freely and not fixed to the outer tube 35 so that it cannot rotate.

[0039] In this embodiment, an outer cylinder 35 is provided on the finger 234, and the rod member 32 is passed through this outer cylinder 35 and sandwiched between the large diameter support portion 34 of the rod member 32 and the nut 36. Therefore, in Figure 3, the vertical cross section of the outer cylinder 35 has a double cross section structure in which the shaft portion 33 of the rod member 32 is disposed at the center and the outer cylinder 35 is disposed around the shaft portion 33 in a ring shape. Therefore, compressive forces from the large diameter support portion 34 and the nut 36 act evenly on the outer cylinder 35, and excessive internal force does not act on only a portion of the outer cylinder 35. Therefore, it is possible to prevent the outer cylinder 35 from being broken or damaged while ensuring space for arranging the rod member 32.

[0040] (First Modification) As shown in FIG. 3, in this embodiment, a finger 234 is provided with an elongated member 31 and an axial force adjusting means 30 for adjusting the axial force of the elongated member 31 .

[0041] In the first modified example, the same components as those in the above embodiment are denoted by the same reference numerals in FIG. 4, and the description thereof will be omitted, and only the different components will be described.

[0042] That is, the insertion member is a connecting structure 37. In the connecting structure 37, a plurality of rigid portions 38 are connected in a row at their connecting points so as to be freely bendable, thereby connecting the rigid portions 38 and the joint portions 38b alternately. A large-diameter support portion 34 is provided at one end of the connecting structure 37, and a thread-forming member 39 is rotatably connected to the other end via a rigid pin 39a having a rotation pin portion 39b. The rigid pin 39a, which serves as a joining means, does not bend even when subjected to a compressive force from the thread-forming member 39, and instead applies the compressive force to the plurality of rigid portions 38. A ball joint configuration may be used instead of the rigid pin.

[0043] The connecting structure 37 has a plurality of rigid portions 38 inserted into the internal space 35a of the outer tube 35, at their mutual connecting points (joint portions 38b) where they can bend freely. The large diameter support portion 34 of the connecting structure 37 is fixed to one end of the outer tube 35. The thread forming member 39 of the connecting structure 37 is exposed from the other end of the outer tube 35, and a nut 36 is threaded into the exposed portion. As in the previous embodiment, the outer tube 35 is sandwiched between the large diameter support portion 34 and the nut 36. However, in this first modified example, the large diameter support portion 34 and the nut 36 are both fixed to the outer tube 35 and cannot rotate.

[0044] The axial force adjusting means 30 is configured by a thread forming member 39 which is a fastening member, and an axial force acts on the connecting structure 37 by rotating the thread forming member 39 .

[0045] In other words, when the thread forming member 39 is rotated in a direction that compresses the outer tube 35, a gradually increasing compressive force acts on the outer tube 35 according to the thread pitch, and as a reaction to this, a gradually increasing tensile force acts on the connecting structure 37 (see Figure 4A).

[0046] When thread forming member 39 is rotated in the direction of extending outer tube 35, connecting structure 37 bends and deforms in accordance with the thread pitch, and the range of motion of joint portion 38b is limited (a structure that prevents bending and deformation beyond a predetermined angle), so that the compressive force can be maintained without rigid portion 38 coming into contact with the inner wall (not shown), or the bending and deformation can be restricted by the inner wall of outer tube 35 (see FIG. 4B). When thread forming member 39 is rotated further from this state, a gradually increasing tensile force acts on outer tube 35 in accordance with the thread pitch, and as a reaction to this, a gradually increasing compressive force acts on connecting structure 37 (see FIG. 4B).

[0047] By varying the screw fastening position (thread engagement position) of the thread forming member 39 in this way, the tensile force and compressive force acting on the connecting structure 37 as axial forces can be adjusted.

[0048] As described above, for the same reasons as in the above embodiment, the first modified example can also prevent resonant vibration of the structure including the fingers 234. In particular, in the first modified example, since not only the tensile force but also the compressive force of the connecting structure 37 can be adjusted, the range of natural frequencies of the structure including the fingers 234 is wide, and resonant vibration of the structure including the fingers 234 can be prevented more reliably than in the above embodiment.

[0049] In the first modified example, the rigid portion 38 of the connecting structure 37 has a chain shape, but it may also have a spherical, ellipsoidal or other shape.

[0050] (Second Modification) 5 is a cross-sectional view of a measurement head using a cross spring 41. The cross spring 41 is held in contact with both the arm member and the measurement head body so as to be sandwiched between them, and functions as a swing fulcrum for the measurement head. A finger 234 is attached to the tip of the arm member, and a probe 300 (contactor) is attached to the tip of the finger 234. A differential transformer 180 is attached to the rear end of the arm member.

[0051] In addition, a compression coil spring 40 is provided between the measuring head body and the arm member to apply a measuring pressure to the measuring element 300, and a stopper screw provided on the measuring head body is used to set the swing lower end of the arm member.

[0052] The measuring head has an arm member that performs a seesaw motion with the cross spring 41 as the fulcrum, so that the amount of movement of the measuring probe 300 when the measuring probe 300 is brought into contact with the workpiece W is detected by a differential transformer, enabling highly accurate measurements to be performed.

[0053] Furthermore, as shown in FIG. 5 , the shaft portion 33, large-diameter support portion 34, outer tube 35, and shaft 182 are fixed together, and the axial force is adjusted by turning the holding member 42 like a nut. This allows the axial force to be adjusted from outside the measuring instrument, thereby adjusting vibration, without rotating the shaft 182 inserted into the differential transformer. That is, in the second modification, unlike the above embodiment, a long member 31 and an axial force adjustment means 30 are attached to a lever shaft 132 connected to one end of the finger 234. The long member 31 includes a rod member 32, which is an insertion member, and an outer tube 35 into which the rod member 32 is inserted. The rod member 32 includes a shaft portion 33 with a threaded portion 33a and a large-diameter support portion 34 fixed to the shaft portion 33. The large-diameter support portion 34 is shaped like a bolt head so that it can easily transmit torque using a rotary tool or the like. The rod member 32 can be substituted with a general-purpose bolt.

[0054] The large diameter support portion 34 is rotatable about the outer cylinder 35, and the threaded portion 33a of the rod member 32 is threaded into a screw hole in the holding member 42. The holding member 42 is a component that holds the finger 234. The holding member 42 is fixed to the outer cylinder 35.

[0055] That is, the outer cylinder 35 is sandwiched between the large diameter support portion (head portion) 34, which is the axial force adjustment means 30, and the holding member 42. When the large diameter support portion (head portion) 34 is rotated, a tensile force acts on the rod member 32 for the same reason as in the above embodiment.

[0056] In the second modified example, the same components as those in the above embodiment are denoted by the same reference numerals in FIG. 5, and the description thereof will be omitted, and only the different components will be described.

[0057] As described above, the second modified example differs in that the finger 234 is provided on the lever shaft 132 instead of the finger 234, but for the same reasons as in the above embodiment, it is possible to prevent resonant vibration of the structure including the finger 234.

[0058] (Third Modification) As shown in Fig. 6, in the third modified example, similar to the above embodiment, a finger 234 is provided with an elongated member 31 and an axial force adjusting means 30. In the third modified example, the same components as those in the above embodiment are denoted by the same reference numerals in Fig. 6, and explanations thereof will be omitted, and only different components will be explained.

[0059] That is, the outer cylinder 35 of the finger 234 is provided with protruding members 43 at multiple locations (six locations in FIG. 5 ) in the longitudinal direction (Y-axis direction). Each protruding member 43 protrudes into the internal space 35a of the outer cylinder 35, and its tip surface abuts against the shaft portion 33 of the rod member 32 at a 0-degree position (the apex of the circumferential direction in the Z-axis direction in side view) and at an intermediate 180-degree rotation position (the lowest point of the circumferential direction in the Z-axis direction in side view; or a position greater than this). By abutting against the shaft portion 33, each protruding member 43 prevents vibration at the intermediate position; that is, when the shaft portion 33 vibrates, the position where the protruding member 43 abuts becomes a vibration node (restraint position).

[0060] In this third modified example, for the same reasons as in the above embodiment, it is possible to prevent resonant vibration of the structure including the finger 234. In particular, in the third modified example, the protruding member 43 abuts against the shaft portion 33 of the rod member 32 at the initial position (the above-mentioned 0 degree position) and the intermediate position (the above-mentioned 180 degree position), so that the natural frequency of the rod member 32 also changes with the protruding member 43.

[0061] As described above, in the third modified example, in addition to varying the tensile force of the rod member 32 as described in the previous embodiment, the natural frequency of the rod member 32 can also be changed by the protruding member 43. Therefore, the range of natural frequencies of the structure including the fingers 234 is wider, and resonant vibration of the structure including the fingers 234 can be prevented more reliably than in the previous embodiment.

[0062] (Other embodiments) In the above embodiment, the adjustment of the natural frequency by adjusting the axial force is applied to a dimension measuring device. However, the mechanism for adjusting the natural frequency by adjusting the axial force can also be applied to other devices as long as the device has a cantilever beam structure. Below, other devices to which an axial force adjustment means is applied will be described.

[0063] Fig. 7 is a cross-sectional view showing another embodiment in which the configuration for adjusting the natural frequency is applied to a conveyor. Conveyor 50 has a conveyor body 51 and a mounting table 52 held by conveyor body 51. This conveyor body 51 is provided with a long member 31 and an axial force adjustment means 30. Conveyor 50 does not have a measuring element 300, and instead has a mounting table 52, but the configuration of each member for adjusting the axial force is the same as in the above-mentioned embodiment of the dimension measuring device. Specifically, the configurations of long member 31 and axial force adjustment means 30 are the same as in the above-mentioned embodiment, and the same reference numerals are used in Fig. 7, and their description will be omitted.

[0064] In this other embodiment, for the same reason as in the above embodiment, it is possible to prevent resonant vibration in a structure having the conveying body 51 as a constituent member.

[0065] (Other variations) In each of the above embodiments and variants, the elongated member 31 is provided with an insert member and an outer tube 35 that extends in the longitudinal direction in the same manner as the insert member, but the outer tube 35 may also be provided separately and independently at two spaced apart locations.

[0066] In each of the above-described embodiments and modifications, the internal space 35a of the outer cylinder 35 may be filled with a fluid and / or powder (damping material), thereby improving the damping performance of the rod member 32, the connecting structure 37, etc.

[0067] In the above embodiment and other embodiments, the large diameter support portion 34 is fixed non-rotatably to one end of the outer cylinder 35, and the nut 36 is configured to be rotatable on the other end of the outer cylinder 35. However, conversely, the large diameter support portion 34 may be rotatably supported on one end of the outer cylinder 35, and the nut 36 may be fixed non-rotatably to the other end of the outer cylinder 35. In this case, the large diameter support portion 34 serves as the axial force adjustment means 30.

[0068] In each of the above-described embodiments and modifications, one side of the insertion member is fixed and the other side is rotatable, but it may be configured so that both sides are selectively rotatable.

[0069] In each of the above-described embodiments and modified examples, the fastening member of the axial force adjustment means 30 has a screw structure, and fine adjustment is possible by changing the thread pitch. However, as described above, the axial force adjustment means 30 may be configured with a fastening member other than a screw.

[0070] In the above embodiment and each modified example, examples have been shown in which the present invention is applied to the finger 234 of the dimension measuring device 60, but the present invention may also be applied to components other than the finger 234 of the dimension measuring device 60, and may also be applied to measuring devices other than those for measuring dimensions.

[0071] In the other embodiment described above, an example was shown in which the mechanism for adjusting the natural frequency by adjusting the axial force was applied to the conveying body 51 of the conveying machine 50, but it may be applied to components other than the conveying body 51, and it can also be applied to devices other than the conveying machine 50. In other words, it can be applied to all devices that have a structure that vibrates as a whole due to an external force (including external vibration). Structurally, even if it is not a conveying machine, if it is a device that has a long member with a cantilever structure, resonant vibration can be prevented by using a similar axial force adjustment means.

[0072] Although the embodiments and modifications have been described in detail above, the present invention is not limited to the specific embodiments, and various modifications and changes are possible within the scope of the claims. Furthermore, it is also possible to combine all or a plurality of components of the above-described embodiments. [Explanation of symbols]

[0073] 31 Long members 32 Rod member (insertion member) 33 Shaft 33a Thread forming part 34 Large diameter support portion (axial force adjustment means) 35 outer cylinder 35a Interior space 36 Nut (fastening member, axial force adjustment means) 37 Connecting structure (insertion member) 38 Rigid part 39 Thread forming member (fastening member, axial force adjusting means) 30 Axial force adjustment means 43 Protruding member 60 Dimensional measuring device 142 Holding stand (main body) 300 Probe

Claims

1. a measuring head that contacts the workpiece; an elongated member that supports the probe at one end and is swingably supported by a main body at the other end; an axial force adjusting means for adjusting the axial force of the elongated member; A dimension measuring device comprising:

2. The elongated member includes an insertion member extending along a longitudinal direction thereof, 2. The dimension measuring device according to claim 1, wherein the axial force adjusting means adjusts the axial force by changing a fixing position of at least one end of the insertion member.

3. The elongated member includes an outer cylinder that accommodates the insertion member, 3. The dimension measuring device according to claim 2, wherein the axial force adjusting means includes a fastening member that fixes the one end of the insertion member that protrudes from the outer cylinder.

4. 4. The dimension measuring device according to claim 3, wherein the other end of said inserting member is fixed to said outer cylinder.

5. 4. The dimension measuring device according to claim 3, wherein the inserting member is configured to be bendable within the outer cylinder, and the other end of the inserting member is joined to the outer cylinder by a joining means.

6. The dimension measuring device according to claim 5 , wherein the insertion member has a structure in which rigid portions and articulated portions are alternately connected along the longitudinal direction.

7. 4. The dimension measuring device according to claim 3, wherein the outer cylinder is filled with a damping material.

8. The dimension measuring device according to claim 3 , further comprising a protruding member that penetrates the outer cylinder and is capable of contacting the inserting member.

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