JPS6120485Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a shape measuring device for measuring the surface shape of an object to be measured.

Generally, in a shape measuring instrument, a stylus that contacts the surface of the object to be measured is attached to one end of an arm, and the vicinity of the other end of this arm is rotatably supported by an arm support, and the center of gravity of this arm is on the stylus side. The stylus is positioned so that it is slightly heavier, so that the stylus is always in contact with the surface of the object to be measured. To measure the surface shape with this shape measuring instrument, the arm support is moved in the axial direction of the arm, and as the arm support moves, the stylus is displaced according to the surface shape of the object to be measured, and the arm is moved. The arm swings around a pivot point, and the swing of the arm is measured by a measuring device such as a differential transformer.

However, in such a conventional shape measuring instrument, the stylus moves in an arc around the rotational fulcrum, so the stylus moves not only in the vertical direction but also in the direction in which the arm support is fed. Therefore, the amount of movement in the feeding direction results in a measurement error, and particularly when the surface shape of the object to be measured has large irregularities, the error becomes large and there is a drawback that accurate measurement cannot be performed.

For this reason, conventionally, one end of a link bar is rotatably attached via a cross spring to the end of the arm opposite to where the stylus is attached, and the other end of this link bar is attached to the arm support via a cross spring. (slide plate), so that when the arm rotates, the link bar swings around the support part to the arm support body, and this swing causes the arm to move in the direction to correct the arc error, and eventually A mechanism has been proposed in which the tip of the stylus moves up and down in a substantially vertical direction and does not cause arc errors, or a mechanism in which parallel links are used instead of link bars. (Tokukai Akira
53-53352).

However, such conventional mechanisms require link bars or parallel links to support the arm, which not only makes it difficult to downsize and simplify, but also makes it difficult for the arm to rotate due to the swinging of these links. There are disadvantages in that the position of the dynamic fulcrum may move up and down, reducing accuracy, or the arm may not be placed in the best position, which may cause unreasonable force to be applied to the arm or the like.

An object of the present invention is to provide a shape measuring instrument with a simple structure that can prevent excessive force from acting on an arm, etc., and can correct arc errors.

In the present invention, the tip of the stylus is placed on a line (hereinafter referred to as the reference line) connecting the fixed fulcrum of the connecting link with the arm support and the rotational fulcrum of the arm itself to make the arm move to correct circular errors. By arranging the arm so that when the arm is positioned, at least the axis of the arm located between the fixed fulcrum of the connecting link and the arm rotation fulcrum substantially coincides with the reference line, a force in an approximately axial direction is applied to the arm. By moving the arm rotation fulcrum in parallel to the feeding direction of the arm support while abutting the straight guide surface provided on the arm support, it is possible to reduce the size and simplify the structure. In addition, the above object is achieved by preventing the vertical movement of the rotational fulcrum of the arm and making it possible to more accurately correct arc errors.

Hereinafter, one embodiment of the present invention will be described based on the drawings.

FIG. 1 schematically shows the overall structure of the shape measuring instrument. In this figure, a column 2 is erected on a base 1, an X-direction drive detection mechanism 3 is attached to this column 2, and it can be moved up and down along the column 2 by driving a handle 4. There is. The X-direction drive detection mechanism 3 is a mechanism that moves the Y-direction detection mechanism 5 in the X direction, that is, in the axial direction of the arm 6 provided in the Y-direction detection mechanism 5, and detects the amount of movement thereof. The X-direction drive detection mechanism section 3 includes a drive motor 7 therein,
The rotation of this drive motor 7 is transmitted to a feed screw shaft 9 via a gear interlocking mechanism 8, and the rotation of this feed screw shaft 9 is detected by a rotation detector 10 such as a rotary encoder.
Detected by A nut member 11 is screwed onto the feed screw shaft 9, and as the feed screw shaft 9 rotates,
It is meant to move in the direction. A Y-direction detection mechanism 5 is connected to the nut member 11 via a connector 12, and is configured to move together with the nut member 11 in the X direction.

The detailed structure of the Y-direction detection mechanism section 5 is shown in FIGS. 2 to 8. In these figures, the Y-direction detection mechanism section 5 includes an arm support 13 made of cast metal or the like, and both sides and top surface of the arm support 13 in the longitudinal direction are covered with a cover 14 having a U-shaped cross section. The end faces perpendicular to the direction are covered by side covers 15 and 16.
At the center of the upper surface of this cover 14, there is provided the connection tool 12.
is arranged, and this connector 12 is connected to the arm support 13 via three stud pins 17 (see FIG. 3).
is fixed to.

As shown in FIGS. 2 and 4, the arm 6 includes a first arm 18 having a substantially small diameter cylindrical shape, and a second arm 18 having a substantially large diameter cylindrical shape that houses the first arm 18 via a bush 19. It is composed of a pair of arms including arm 20. One end of the first arm 18 protruding from the second arm 20 is made into a thin-walled pipe to reduce weight, and is joined via a joint 21, and a stylus 2 is attached to the joined end.
2 is fixed in a radially protruding state.
In addition, the joint 21 can be turned upside down, and the stylus 22 can be oriented not only downward as shown in the figure, but also upward, so that it can measure not only the upper surface of the object to be measured 23 but also the upper wall of the side hole, etc. There is. At this time, the joint 21 is provided with a stopper mechanism 24 consisting of a ball, a recess, etc., so that the joint 21 can be accurately stopped at the 180 degree inverted position. Moreover, even if the position of the stylus 22 is reversed, the joint 21
The stylus 22 is rotated on the central axis of the second arm 20 so that the tip of the stylus 22 is at the same position as before reversal.

The first arm 18 and the second arm 20 are made slidable in their axial directions, and the biasing means 2
5, so that predetermined mutual positions are always maintained. That is, a set screw 26 is fixed to the right end of the first arm 18 in FIG.
A portion of the biasing means 25 is formed between the sliding plate 27 and a flange portion 28 fully provided on the first arm 18. A first compression coil spring 29 is interposed so that the sliding plate 27 is always in contact with the head of the set screw 26. Further, the outer periphery of the sliding plate 27 is made slidable on the inner periphery of the second arm 20, and the biasing means is provided between the sliding plate 27 and the inner step of the second arm 20. A second compression coil spring 30 constituting the remainder of the second arm 25 is interposed, and this second compression coil spring 30 allows the sliding plate 27 to be attached to a cap nut 3 screwed into the right end of the second arm 20.
It is adapted to come into contact with the inner end surface of 1. A recess 32 is formed in the inner end surface of the cap nut 31 so that the head of the set screw 26 can move within this recess 32 in the axial direction of the set screw 26.
As a result, the sliding plate 27 is pressed against the inner end surface of the cap nut 31 by the second compression coil spring 30, while the set screw 2 is pressed by the first compression coil spring 29.
6 is pressed against the right end surface of the sliding plate 27,
The first and second arms 18, 20 normally maintain the state shown. In this state, the first arm 18
is pressed to the right in FIG. 2 with a force greater than the biasing force of the first compression coil spring 29, the first arm 18 resists the biasing force of the first compression coil spring 29 , the sliding plate 27 and the set screw 26 are released from contact, and the first arm 18 is moved to the second position with a force greater than the biasing force of the second compression coil spring 30.
When pulled to the left in the figure, the head of the set screw 26 fixed to the right end of the first arm 18 moves the sliding plate 2.
7 is pressed to the left, and the second compression coil spring 30
The first arm 18 is made to move to the left together with the sliding plate 27 against the urging force of.

The flange portion 28 of the first arm 18 includes:
A fulcrum shaft 33 serving as an arm rotation fulcrum is inserted in the horizontal direction, that is, in a direction perpendicular to the plane of the paper in FIG. A bearing 35 is attached to each of these protrusions. This bearing 35 is connected to a pair of needles 36 fixed to the arm support 13 which is a straight guide surface.
(See FIG. 5) The arm 6 consisting of a pair of first and second arms 18 and 20 is brought into contact with the
is supported so as to be rotatable around a fulcrum shaft 33 that serves as a fulcrum for arm rotation and to be slidable in the axial direction. Further, the fulcrum shaft 33 has its central portion fixed by a screw shaft 38 inserted through a long hole 37 (see FIG. 2) provided on the upper surface of the second arm 20. An actuating member 39 is fixed to the upper end of this screw shaft 38, and an actuating arm 42 of a micro switch 41 as a detection mechanism is attached to the outer periphery of the second arm 20 via a bracket 40. is in contact. As a result, when the first arm 18 moves against the biasing means 25 and relative movement occurs between it and the second arm 20, it can be detected by the micro switch 41. The switch 41 is connected to the power supply circuit of the drive motor 7 explained in FIG.

One end of a balancer shaft 43 extending in the axial direction of the arm 20 is fixed to the axial center of the cap nut 31 attached to the right end of the second arm 20, and the other end is attached to the outside of the side cover 16. It has been extended until. A balancer weight 44 is attached to the extension of the balancer shaft 43.
3 is mounted movably in the axial direction of the bolt 45.
This allows the position to be fixed.
This balance weight 44 is fixed at the arm 6 and integrally with the fulcrum shaft 33.
The weight on the stylus 22 side relative to the fulcrum shaft 33 of the part that swings around is set to be slightly heavier than the weight on the balancer weight 44 side relative to the fulcrum shaft 33, so that in the free state, the stylus 22 is slightly The surface of the object to be measured 23 is brought into contact with the surface of the object to be measured 23 with a strong contact force.

A pin 46 is provided in the middle of the balancer shaft 43.
is provided upright, and this pin 46 faces an eccentric cam 48 fixed to the output shaft of a DC motor 47. As a result, when the motor 47 is driven and the eccentric cam 48 comes into contact with the pin 46, the balance weight 44 side of the arm 6 is pushed down, and the stylus 2
When the stylus 22 and the object to be measured 23 are brought out of contact with each other and the motor 47 is stopped at the maximum eccentric portion (maximum diameter position) of the eccentric cam 48, the arm 6 moves the stylus 22 to the object to be measured 23. It is designed to be stopped at the farthest point from the On the other hand, when the motor 47 is driven again from this stopped position,
While in contact with the cam surface of the eccentric cam 48, the pin 46 slowly rises due to the weight unbalanced force of the arm 6, and the stylus 22 also comes into gentle contact with the surface of the object to be measured 23, causing damage to the stylus 22. etc. will be prevented. Further, the DC motor 47 is screwed and fixed to a stand 49 that is integrally provided upright from the arm support 13, and the balancer shaft 43 extends through a through hole 50 provided in the stand 49. Furthermore, stand 4
As shown in FIG. 7, limit switches 51 and 52 are installed on both sides of the upper part of the eccentric cam 48, respectively. It is enabled to come into contact with the pin 55.
These limit switches 51 and 52 are connected to the power supply circuit of the DC motor 47, and when activated by the operating pin 55, turn off the power to the DC motor 47 and stop the DC motor 47. As a result, when the limit switch 51 is activated, the motor 47 is stopped at the position shown in FIG. 7, where the maximum diameter position of the eccentric cam 48 is farthest from the pin 46 of the balancer shaft 43, while the limit switch 52 is activated. Then, the motor 47 is stopped at the position where the maximum diameter position of the eccentric cam 48 contacts the pin 46 and raises the stylus 22.

A spring hanging pin 56 is horizontally implanted in the actuating member 39 fixed to the upper end of the screw shaft 38 that fixes the fulcrum shaft 33 to the first arm 18. A coil spring 59 is stretched between the spring hanging pin 58 and the provided spring hanging pin 58. As shown in FIG. 6, this rotating body 57 is fixed to one end of a rotating shaft 61 that is rotatably supported by a pair of stands 60 that are erected integrally with the arm support 13. A knob 62 is screwed into the other end and is prevented from rotating by a pin 63. The large-diameter portion of the knob 62 for operation is protruded outward from the cover 14.
By rotating the knob 62 from the outside,
The rotating body 57 can be rotated and moved from the position shown by the broken line in FIG. 2 to the position shown by the chain line. A moderation mechanism 64 is provided between one side of the rotating body 57 and one stand 60, and the rotation angle of the rotating body 57 is regulated. This moderation mechanism 64
is a socket 65 attached to the stand 60.
and the compression spring 6 housed within this socket 65.
6 and a ball 67 that is constantly pressed against one side of the rotating body 57 by the compression spring 66. By fitting this ball 67 into a recess provided on one side of the rotating body 57, a sense of moderation is achieved. It is becoming possible to obtain it. Further, the spring hanging pins 56, 5
The coil spring 59 stretched between the rotating body 5
7 is always in the position indicated by the broken line in Figure 2,
The knob 62 is rotated so that the rotary body 57 is in a slack state that does not generate any urging force.
When placed in the position indicated by the chain line in FIG. 2, a tensile force is applied to the arm 6 via the threaded shaft 38 and
It is designed to apply clockwise rotational force around point 3. As a result, when the rotating body 57 is rotated to the chain line position, the left end of the first arm 18 in FIG. A predetermined contact force is applied to the side, and measurements can be taken while contacting the upper wall of the horizontal hole provided in the object to be measured 23 with a predetermined contact force without changing the position of the balance weight 44. ing.

3 and 4, a notch 68 is formed on one side of the center of the second arm 20, and a differential transformer 69 is erected on the arm support 13 at this notch 68. A core 70 of this differential transformer 69 is attached to the outer periphery of the second arm 20 via a bracket 71 so that the amount of rotation of the second arm 20 about the fulcrum shaft 33 can be measured.

A support link 75 having a generally U-shaped plan view is fixed to the left end of the second arm 20 in FIGS.
One end of a connecting link 78 is rotatably supported between the U-shaped opening side ends of the support link 75 via a bearing 76 and a pivot 77, and the other end of this connecting link 78 is supported between a pivot 79 and a bearing. It is rotatably supported by a pair of stands 81 integrally projecting from the arm support 13 via a support 80, and this support is used as a fixed fulcrum for the connection link 78. As shown in FIG. 8, this connecting link 78 is formed by flattening both sides of a cylinder having a through hole 82 with an oval cross section in the internal axis direction, and the pivot 77, 79 is configured to protrude, and the first arm 18 passes through the through hole 82 at a predetermined interval. These support links 75, bearings 76, 80,
The pivots 77, 79, the connecting link 78, and the stand 81 of the arm support 13 constitute an arc error correction mechanism for the arm 6.

A line P connecting the rotation fulcrum of the arm 6, that is, the center line of the fulcrum shaft 33, and the fixed fulcrum of the connecting link 78, that is, the center axis of the pivot 78 (see FIG. 2);
In other words, the line defined as the reference line (to be exact, 1
Although it is not a book line but a plane, it appears as a line in FIG. 2, so for convenience of explanation, it is called a line) which is parallel to the feeding direction of the arm support 13, that is, the X direction. Further, the axis of the arm 6 at least in the portion between the arm rotation fulcrum and the fixed fulcrum of the connecting link 78 is determined when the tip of the stylus 22 is located on the reference line P (hereinafter referred to as the reference position of the arm 6). The arm 6 is positioned approximately on this reference line P, so that the force applied to the arm 6 is approximately the tension or compression in the axial direction of the arm 6.

Next, the operation of this embodiment will be explained.

The object to be measured 23 is placed on the base 1 directly or via a predetermined mounting table or the like. Next, the handle 4 is rotated so that the stylus 22 faces the starting position of the part to be measured of the object to be measured 23 with an appropriate gap, and the stylus 22 is moved through the X-direction drive detection mechanism 3 and the Y-direction detection mechanism 5. The vertical direction (Y direction) position of the stylus 22 is set by driving the drive motor 7 of the X direction drive detection mechanism section 3 to set the left and right direction (X direction) position of the stylus 22.
At this time, the DC motor 47 that drives the eccentric cam 48
is stopped with the maximum diameter portion of the eccentric cam 48 in contact with the top of the pin 46. Therefore, the stylus 22 is stopped at a position higher than the measurement position, and the stylus 22 is stopped at a position higher than the measurement position.
is located slightly above the left end of the object to be measured 23 in FIG.

Next, the DC motor 47 is driven to drive the eccentric cam 48.
When rotated, the weight on the stylus 22 side from the fulcrum shaft 33 of the arm 6 is slightly larger than the weight on the balancer weight 44 side from the fulcrum shaft 33.
Due to the unbalanced force of this weight, the upper end of the pin 46 slowly rises while contacting the cam surface of the eccentric cam 48, while the stylus 22 slowly descends and contacts the surface of the object to be measured 23 without impact. . In this state, the drive motor 7 is driven again to rotate the feed screw shaft 9 via the gear interlocking mechanism 8,
When the Y-direction detection mechanism 5 is moved to the right in FIG. be moved towards This vertical movement of the stylus 22 is caused by the fulcrum shafts 3 of the arms 6, that is, the first and second arms 18, 20.
3, and this first and second
The rotation of the arms 18 and 20 is converted into the movement of the core 70 attached to the second arm 20 via a bracket 71, and the amount of displacement thereof is detected by the differential transformer 69. On the other hand, the X direction detection mechanism 5
The amount of displacement in the direction is detected by detecting the rotation of the feed screw shaft 9 with a rotary encoder 10,
By detecting the displacement in the X direction, that is, the feed, and the displacement in the Y direction, the surface shape of the object to be measured 23 can be measured.

When measuring the object to be measured 23, if the surface shape of the object to be measured 23 does not have large irregularities, there is not much of a problem, but if the irregularities become large, so-called circular arc error becomes a problem. That is, stylus 2
2 should ideally always move in the vertical direction (Y direction), but in reality it is a rotational movement around the fulcrum shaft 33, and therefore the distance between the fulcrum shaft 33 and the stylus 22 However, if the vertical movement of the stylus 22, that is, the rotation angle of the arm 6, increases beyond a certain level, the X-direction component of the displacement due to the upward movement of the stylus 22 becomes large enough to not be ignored, and this causes a measurement error. Therefore, some kind of correction is required. Is required. In this embodiment, this correction is performed by an arc error correction mechanism including a support link 75, a connecting link 78, and the like. Now, if the stylus 22 is moved upward, the first arm 18 will rotate clockwise, and the second arm 20 and the support link 7 integral with the second arm 20 will be rotated clockwise.
5 also rotates clockwise. On the other hand, a connecting link 78 connected to this support link 75 via a bearing 76 and a pivot 77 is
9 and the arm support 1 via the bearing 80
3, the connecting link 78 is rotated counterclockwise, and the connecting link 78 and the second arm 20 are bent upward at the pivot 77 position. do. For this reason, the distance between the pivot 79 supported at a fixed point by the stand 81 and the fulcrum shaft 33 tends to decrease, but since the pivot 79 is supported at a fixed point, the fulcrum shaft 33
is moved to the left in FIG. 2 on the needle 36 by the action of the bearing 35, and the first arm 18 and stylus 22 are also moved to the left accordingly.
Therefore, as the stylus 22 rises, the stylus 22 is moved to the left by the action of the correction mechanism.On the other hand, when viewed from the rotation side of the stylus 22 about the fulcrum shaft 33, as the stylus 22 rises, the stylus 22 moves to the left. The more the stylus arm 6 rises, the more it moves to the right due to the X-direction component caused by the rotation of the stylus arm 6. These two actions cancel each other out, and eventually the stylus 2
2 rises almost vertically, and the fulcrum shaft 33 slides in the axial direction without moving up and down on the needle 36, which is a straight guide surface, so the rotation centers of the arm 18 and the stylus 22 are always within the reference line. This prevents arc errors from occurring.

Next, rotate the left half of the first arm 18 at the joint 21 so that the stylus 22 faces upward,
A case will be described in which the shape of the upper surface of the inner wall of the horizontal hole of the object to be measured 23 is measured. When measuring with the stylus 22 facing upward, an upward biasing force is applied to the stylus 22, contrary to the above, and the object to be measured is
It is necessary to perform measurements while in contact with a predetermined relatively small contact force. For this purpose, it is possible to adjust by moving the balance weight 44,
When the stylus 22 is returned to its original position and directed downward, the balance weight 44 must be moved again for adjustment, which is cumbersome. Therefore, in order to apply an upward biasing force to the stylus 22 without moving the balance weight 44, a rotating body 57 rotated by the knob 62 and a coil spring 59 are provided. That is, when the rotating body 57 is positioned as shown by the broken line in FIG. No urging force is added. On the other hand, when the knob 62 is rotated and the rotating body 57 is moved to the position shown by the chain line in FIG. A tensile force acts. Therefore, the screw shaft 38 is biased clockwise around the fulcrum shaft 33, and the arm 6
is also biased clockwise. If the biasing force of the coil spring 59 is appropriately selected, a predetermined upward biasing force can be applied to the stylus 22 without moving the balance weight 44, and the upper surface of the inner wall of the horizontal hole of the object to be measured 23 can be measured. can.

According to this embodiment as described above, the arm 6 is
When the stylus 22 is on the reference line P, that is, when the arm 6 is at the reference position, the axis of at least the portion between the arm rotation fulcrum and the fixed fulcrum of the connecting link 78 is approximately on the reference line P. Because of this provision, unreasonable forces such as bending moments are less likely to be applied to the arm 6, and therefore distortion and the like are less likely to occur in the arm 6, reducing measurement errors. Further, since the arm 6 and its related parts are substantially on the reference line at the arm reference position, the accumulation of errors can be reduced. Further, since the cylindrical connecting link 78 is used as the arc error correction mechanism and the arm 6 is passed through the connecting link 78, the device can be made smaller. Furthermore, the connecting link 78
are relatively thin, so when assembling the bearings 76, 80 and the pivots 77, 79, if you push the bearings 76, 80 a little more toward the pivots 77, 79, the connection link 78 is deflected, and the deflection of the connecting link 78 absorbs the gap (play) between the bearings 76, 80 and the pivots 77, 79 that occurs during long-term use, so that no play occurs even during long-term use. There is no. In addition, the core 70 is connected to the second arm 20
Since it is fixedly attached to the outer periphery of the core 70 via the bracket 71, the structure for attaching the core 70 can be simplified, and the movement of the arm 6 can be accurately transmitted. In order to follow the axial movement of the first and second arms 18 and 20 due to the provision of the stylus 22 protection mechanism and circular arc error correction mechanism,
Since the arm 6 is supported by the bearing 35 and the needle 36 via the fulcrum shaft 33, the contact between the two becomes a point contact, and the movement is smooth. 36, it can be provided at low cost. Furthermore, the movement of this fulcrum shaft 33 is caused by the weight of the arm 6, balancer weight 44, etc.
5 is in contact with the needle 36, the fulcrum shaft 33 can be moved with low friction, and the height of the arm 6 remains unchanged even when the fulcrum shaft 33 moves. The arc error can be corrected more accurately, and the structure can be made simpler and more compact than the conventional structure in which the arm is suspended from a link using a cross spring or the like. Also, a rotating body 57 positioned by the moderation mechanism 64 and a coil spring 59 connected at one end to the rotating body 57.
Since the rotating body 57 can be rotated by the knob 62, the direction of applying the measuring force to the stylus 22 can be easily switched without adjusting the balance weight 44.

In addition, in the case where a breakage prevention mechanism for the stylus 22 is not provided, a single arm 6 may be used. Further, the connecting link 78 is not limited to a ring-shaped cross section as in the embodiment described above, but may be a U-shaped cross-section with one side of the ring open. In this case, the through hole 82 becomes a through groove. Further, the connecting link 78 may be divided into two pieces, one on each side of the arm 6, and supported at a side position of the rotation surface of the arm 6. In short, the connecting link 78 only needs to be one that allows the arm 6 to pass through in a substantially straight line. Further, in the embodiment described above, the arm 6 is supported by two bearings 3 each via the fulcrum shaft 33.
5 and the needle 36, but the present invention is not limited to this, and the bearing 35
and the needle 36 is omitted, a pair of integral protrusions are provided on the arm support 13 in the axial direction of the arm 6, and the upper surface of the protrusion is turned into a smooth straight surface.
The fulcrum shaft 33 may be directly supported by this protrusion.

As described above, according to the present invention, it is possible to provide a shape measuring instrument that can correct arc errors with a simple mechanism and that does not apply excessive force to the arm.

[Brief explanation of the drawing]

Fig. 1 is a front view showing the overall structure of an embodiment of the shape measuring instrument according to the present invention, Fig. 2 is an enlarged sectional view of the main part of Fig. 1, and Fig. 3 is a view taken from the - line arrow in Fig. 2. 4 is a sectional view taken approximately along the axis of the arm in FIG. 2, FIGS. FIG. 3 is a perspective view of the connecting link shown in the figure. 5... Y direction detection mechanism section, 6... Arm, 13
...Arm support, 22...Stylus, 23...
...Object to be measured, 33...Fully shaft as arm rotation fulcrum, 35...Bearing, 36...Needle forming straight guide surface, 69...Differential transformer, 7
5...Support link, 78...Connection link, 79...
...Pivot as a fixed fulcrum, 82...Through hole,
P...Reference line.

Claims (1)

[Claims for Utility Model Registration] (1) An arm having a stylus at one end, and a portion near the other end of this arm that is rotatably supported on an arm support and in a direction parallel to the feeding direction of the arm support. an arm rotation fulcrum that is movable, one end of which is rotatably supported by the arm, and the other end of which is rotatably supported by a fulcrum fixed to an arm support at a position lateral to the rotation surface of the arm; When the stylus tip is located on a reference line that includes an arm rotation fulcrum and a fixed fulcrum of the connection link, at least the arm rotation fulcrum and the fixed fulcrum of the connection link are connected. The axial center of the arm of the portion located between the arms is provided so as to substantially coincide with the reference line, and the arm rotation fulcrum is in contact with the straight guide surface provided on the arm support while moving the arm support. A shape measuring device characterized in that it is provided movably in a direction parallel to the feeding direction of the shape measuring device. (2) In claim 1 of the utility model registration claim, the connecting link has a through hole or a through groove through which the arm can be inserted, and the arm is extended to the outside by passing through the through hole or through groove. A shape measuring instrument characterized by: