JPH0477243B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention provides a probe that is supported movably in three orthogonal axes directions via an X slider, a Y slider, and a Z slider attached to a base, and is applied to a workpiece surface. The present invention relates to an improvement in a tracer for measuring a surface shape, which detects the surface shape of a workpiece as an electrical signal while contacting and sliding along the surface of the workpiece.

[Conventional technology]

Attach a surface shape measurement tracer to a CNC three-dimensional measuring machine, etc., and slide the probe of this tracer on the surface of the workpiece (object to be measured).
A contact surface shape measuring device that continuously tracks and measures the surface shape of a surface is known.

Conventionally, this type of surface profile measurement tracer
An X slider, a Y slider, and a Z slider that are movable in each axis direction are sequentially attached to a base that is fixed to a CNC three-dimensional measuring machine, etc., and one of them is
The gauge head is fixed to two sliders, and the gauge head is movable in three orthogonal axes directions with respect to the base, and when not in contact with the workpiece, the gauge head can be moved to a neutral position with respect to the base, that is, the origin of X, Y, and Z. Generally, the structure is provided with a neutral position holding means for returning to the neutral position. For example, U.S. Pat.
In the surface profile measurement tracer disclosed in No. 3869799, each slider is supported by parallel springs, and the parallel springs allow each slider to move in each axial direction to ensure measurement force, and furthermore, the measuring head is A neutral position holding means for returning to the origin is formed. However, there was a drawback that the error in the Z-axis direction caused by variations in positional accuracy, nonlinear characteristics, and degree of deformation when assembling and fixing the parallel springs was large, resulting in directional characteristics in the measured values. On the other hand, X, Y, Z
In order to provide stable measurement force (contact force) or movement characteristics in the three-axis directions of the An improved surface shape measuring tracer is disclosed in Japanese Patent Laid-Open No. 2003-12002, which has a configuration in which it is slidably supported in orthogonal directions and the neutral position holding means is formed from a return spring, eliminating the drawbacks of the return spring.
61-50007.

[Problem that the invention seeks to solve]

However, even the above-mentioned conventional surface shape measuring tracers, especially the improved latter tracers, are no longer able to satisfy current demands such as reduction in size and weight and high precision measurement.

In other words, since each slider is assembled in a so-called three-stage stacking system in which each slider is assembled so as to be able to slide freely in orthogonal axes directions one after another, it becomes large and not only puts a heavy load on the contact type surface profile measuring device, but also narrows its effective measurement space. There were problems in that the measurement efficiency deteriorated and the workpieces had to be limited to small ones. Further, the fact that the neutral position holding means is interposed between each slider or disposed on the outer periphery of each slider also leads to further increase in size.

Furthermore, when the surface shape measuring tracer becomes larger, there is a problem in that the characteristics of the tracer itself cannot be improved beyond a certain level. In other words, the above 3
In the structure of the tiered stacking method, the loads on the sliders other than the slider disposed at the lowest level increase, resulting in differences in movement characteristics and the directionality of the measured values becoming more pronounced. Furthermore, the biasing force of the neutral position holding means must be increased, making it difficult to reduce the measuring force, which not only tends to cause measurement errors, but also causes problems such as the inability to measure the shape of plastic products and the like. Also,
In order to smoothly slide and guide the connections between the sliders, the finishing accuracy of each part must be improved, and assembly and adjustment requires excessive labor and time, which is also economically disadvantageous. Furthermore, the neutral position holding means is generally formed of a homing means in the horizontal plane and an origin returning means in the vertical plane, but due to the length of the structure, the structures, loads, and biasing forces of the two means are naturally different. This caused directional variations and further complicated problems such as natural vibration.

The present invention was made in view of the above circumstances, and its object is to provide a surface shape measuring tracer that is small and lightweight and has excellent directionality and responsiveness.

[Means for solving problems]

The present invention focuses on the fact that the above-mentioned conventional problems are caused by the slider structure using a three-stage stacking method, and has two
The above-mentioned drawbacks are solved by a structure in which two sliders are directly supported on a common base so that they can be slidably guided and their positions can be regulated, and the neutral position holding means of the probe is accommodated in each slider.

For this reason, the X slider attached to the base fixed to the movable body of the measuring device, the Y slider, and the Z slider are used to contact and slide the probe, which is supported movably in three orthogonal axes directions, along the workpiece surface. In the surface shape measurement tracer that detects the surface shape of a workpiece as an electrical signal while moving the workpiece, the Y slider is supported on the base body so as to be movable in the Y-axis direction and immovable in the X and Z-axis directions, and The X slider is supported on a slider so as to be movable in the X-axis direction and immovable in the Z-axis direction, and the Z slider is provided with a measuring element and has a hollow cylinder portion extending in the Z-axis direction. An XY origin return means is provided which is movable in the axial direction and is formed of a wire spring whose base end is fixed to the base body and whose distal end is inserted into the hollow cylindrical portion and returns the X and Y sliders to the origin, The above object is achieved by providing a Z origin return means which is housed in a hollow cylindrical portion and is formed of a coil spring for returning the Z slider to its origin.

[Effect]

In the present invention having such a configuration, the Z slider mounted on the X slider (or Y slider) so as to be movable in the Z-axis direction, that is, the measuring tip fixed to the Z slider, is brought into contact with the workpiece, and the base body and the workpiece are moved relative to each other. When moved, the X slider and Y slider, which are directly supported by the base body, slide in the X-axis direction and the Y-axis direction while their positions are restricted in the Z-axis direction. It can be slid smoothly. Furthermore, when the probe is released from the pressing force in the X-axis direction and the Y-axis direction, the XY origin return means made of a wire spring acts, and when the probe is released from the pressing force in the Z-axis direction, the return means made of a coil spring acts. The Z origin return means works, and the measurement person returns X, Y,
It automatically returns to the Z origin and is held at the neutral position.

〔Example〕

A preferred embodiment of the shape measurement tracer according to the present invention will be described based on FIGS. 1, 2, and 3 to 7.

The shape measurement tracer of this embodiment is roughly divided into a base body 10, an X slider 20, a Y slider 40, a Z slider 50, a neutral position holding means 60, and a displacement detection means 80.
The slider 40 is directly supported on the base 10, and the Z
The slider 50 is supported by the X slider 20 in a two-stage stacking system, and the neutral position holding means 60 is housed in each slider to achieve lightweight and compact design.

Each component will be explained below.

As shown in FIGS. 1 to 4, the base 10 is fixed to a movable body of a contact type surface shape measuring device (not shown), and is composed of an upper plate 11, side plates 19l and 19r, and a lower plate 17. . A hollow portion 15 having a rectangular cross section is formed in the base 10 and extends horizontally through the base 10 in a direction (X axis) perpendicular to its longitudinal direction (Y axis).

That is, the hollow portion 15 is located at the guide surface 16 of the upper plate 11.
The slide members 31, which are part of the X slider 20, and the slide members 46l, 46r, which are part of the Y slider 40, are surrounded by parallel planes spaced apart vertically (Z axis) between u and the guide surface 16d of the lower plate 17. It is for fitting. In addition, the upright portion 13 of the upper plate 11
As shown in FIG. 2, guide surfaces 14l and 14r, which are parallel side surfaces spaced apart in the X-axis direction, are formed on the outer surface of the Y slider 4.
0 sliding surfaces 43l and 43r are brought into contact with each other to restrict movement of the Y slider 40 in the X-axis direction.
Therefore, instead of the conventional configuration in which the Y slider 40 is movably supported by the X slider 20, or conversely, the X slider 20 is movably supported by the Y slider 40,
Since both the sliders 20 and 40 are directly slidably guided, the length can be reduced at least in the Z-axis direction.
Further, a female thread 12 is provided in the center of the upper plate 11, and a through hole 18 is provided in the center of the lower plate 17. Note that the symbol B in FIG. 4 is a reference line indicating the center of the hollow portion 15 in the Y-axis and Z-axis directions, and the symbol A is a reference line indicating the center of the base body 10 in the X-axis and Y-axis directions. Yes, that is, it is the Z axis.

As described above, the X slider 20 is supported by the base 10, and as shown in FIGS. 1, 2, 6, and a part of FIG.
The slide member 31 is bolted to the upper side of the main body 21 and is a part of the X slider 20, and the lid member 35 is bolted to the lower side of the main body 21. As shown by the same reference lines A and B in FIGS. 4 and 6, the slide member 31
5, its sliding surface 32u is in close contact with the guide surface 16u of the base body 10, and its sliding surface 32d is in close contact with the guide surface 16d. Therefore, both guide surfaces 16u, 1 are connected to the air pipe 90 attached to the base body 10.
If compressed air is supplied to 6d to form an air bearing, the slide member 31 (X slider 20) becomes immovable in the Z-axis direction and movable in the X-axis direction. Note that the slide member 31 is a Y slider 40.
It is also movable in the Y-axis direction.

As shown in FIGS. 1, 2, and 6, the main body 21 is provided with a rectangular hollow part 23 penetrating in the center thereof, that is, on the Z-axis axis, and the inner surfaces on all four sides thereof are provided with a guide surface 24.
a to d, and these guide surfaces 24
Compressed air is jetted and supplied from an air pipe 91 to a to d. In addition, as shown in parts of FIGS. 1 and 7, a lid member 3 bolted to the lower part of the main body 21 is provided.
A cylindrical portion 36 extending upward is provided at the center of the cylindrical portion 5 .

The Y slider 40 is supported by the base body 10 as described above, and as shown in FIGS. 1, 2, and 5, a pair of upper plates 41l and 41r are disposed opposite to each other with the base body 10 in the X-axis direction. A pair of lower plates 49l, 49r
and a side plate 45l that connects these upper and lower plates,
45r (consisting of a pair sandwiching the base 10 in the X-axis direction)
It consists of an approximately square pipe when viewed from the front, and approximately H when viewed from the side.
It is assembled into letters. And side plate 45l (4
5l) As seen in FIGS. 1 and 5, there is provided a slide member 46l that is fitted through the hollow part 15 of the base body 10 in the X-axis direction, and the side plate 45r
A slide member 46r is similarly provided between (45r). These slide members 46l, 46
The dimension r in the Z-axis direction is the same as that of the slide member 31 of the X slider 20, and the slide member 31 is sandwiched in the Y-axis direction via an air bearing supplied from an air pipe 91. Sliding surfaces 47u, 47 are provided on the upper side of each slide member 46l, 46r.
Sliding surfaces 47d and 47d are formed on the lower side of u, respectively. Therefore, when compressed air is supplied from the air pipe 90 to the guide surfaces 16u and 16d of the base 10 to form an air bearing, the Y slider 40 cannot move in the Z-axis direction but can move in the Y-axis direction with low friction.

The position of the Y slider 40 in the X-axis direction is controlled by guide surfaces 14l, 14r provided on the outside of the upright portions 13, 13 of the base 10, and upper plates 41l, 41r.
This is achieved through cooperation with the sliding surfaces 43l and 43r, and is immovable in the X-axis direction. Further, air bearings are formed on the guide surfaces 14l and 14r to allow smooth movement of the Y slider 40 in the Y-axis direction. Also,
Reference lines A and B in FIGS. 4 and 5 are the same reference line.

Next, the Z slider 50 has a measuring element 58 (having a stylus 59) attached to the lower end side via a collar 57.
is supported by the X slider 20 as described above, and as shown in FIGS. An opening 53 is provided. The four side peripheral surfaces of the main body 51 are sliding surfaces 52a to 5 corresponding to the guide surfaces 24a to 24d of the X slider 20.
Form 2d. That is, the Z slider 50
It is fitted into the slider 20 and can move in the Z-axis direction with low friction via an air bearing using compressed air supplied from the air pipe 91. Moreover, the square hollow part 23 of the X slider 20 and the square column-shaped main body 51 fitted therein
This function functions to prevent the Z slider 50 from rotating around the Z axis A with respect to the X slider 20.
In this way, the X slider 20 and the Y slider 40 are guided and supported directly by the base 10, and the Z slider 5
0 is guided and supported by the X slider 20, so
When a pressing force is applied to the gauge stylus 58 due to a shape change from the work, the gauge stylus 58 is displaced in three axial directions,
The amount of movement displacement is detected as the amount of movement of each slider. Displacement detection means 80 provided for this purpose is formed from an X sensor, a Y sensor, and a Z sensor. The X sensor consists of a scale 82 attached to the base 10 and a detector 83 fixed to the protrusion 26 of the X slider 20, as shown in FIG. The Y sensor consists of a scale 85 attached to the upright part 42 of the Y slider 40 and a detector 86 fixed to the upright part 13 of the base 10, as shown in FIG. As shown in the figure, it is formed from a scale 88 that is integrally attached to the X slider 20 and a detector 89 that is fixed to the Z slider 50 via a support member 56 that penetrates the opening 25 of the X slider 20 from the inside to the outside. Both sensors are photoelectric type.

Next, the neutral position holding means 60
In a non-contact state where no pressing force is applied to the stylus 59 from the workpiece, the stylus 5
In this embodiment, there is an XY origin return means 61 for returning and maintaining the measuring stylus 58 to its origin in the XY plane, and a means for returning and maintaining the origin on the Z axis. Z origin return means 7
It is composed of 1. First, the XY origin return means 61 is formed of a so-called wire spring 63 in the shape of a rod, the base end 64 of which is fixed to the base body 10 via a nut member 62 screwed into the female screw 12 so that its position in the Z-axis direction can be adjusted. At its tip 65 is an X slider 2
A ball 66 that is slidable in the Z-axis direction is attached to the hollow cylindrical portion 37 of the ball 66. Note that, on the contrary, it is also possible to make the base end 64 slidable in the Z-axis direction with respect to the base body 10 and to fix the distal end 65 to the X slider 20 or the Z slider 50. The X slider 20 (hollow cylindrical portion 37) and the ball 66 have a shape sufficient to eliminate looseness in the X and Y axis directions, and in order to further reduce the sliding resistance (remove the damper effect). The cover member 35 of the X slider 20 is provided with an air hole 39. Further, in order to ensure uniform measurement force and return force in any direction on the XY plane, the wire spring 63 is arranged to be aligned with the Z axis in an unloaded state.
Therefore, the through hole 18 of the base body 10, the X slider 2
0 through hole 33, upper opening 5 of Z slider 50
3. Cylindrical portion 36 of the X slider 20 (hollow cylindrical portion 3
7) and the probe 58 (stylus 59) are assembled concentrically. Therefore, when an external force is applied to the stylus 59 in the X-axis direction and/or the Y-axis direction, the X slider 20 and the Y slider 40 can smoothly slide in the axial direction against the biasing force of the wire spring 63. on the other hand,
The wire spring 63 allows both sliders 20 and 40 to slide, and when the external force is removed, allows both sliders 20 and 40 to return to their original positions (origins) with respect to the base body 10. Both sliders 2
When the ball 66 moves by 0 and 40, the ball 66 moves toward the cylindrical portion 36.
The stylus 59 slides on the sliding surface 38 in the Z-axis direction.
The position in the Z-axis direction is held constant. Furthermore, the biasing force of the wire spring 63 becomes the contact force of the stylus 59 against the workpiece, that is, the measuring force, but the deforming force of the wire spring 63 in all directions is uniform, making the measuring force constant in any direction on the XY plane. be able to. Note that the measuring force is applied by rotating the nut member 62 and applying the force to the wire spring 6.
The increase or decrease can be adjusted by changing the effective length of No. 3 (the position of the ball 66 in the Z-axis direction).

Further, the Z origin return means 71 has an upper end 73 locked to the Z slider 50 and a lower end 74 locked to the cylindrical portion 36.
It is comprised of a coil spring 72 that is fitted and locked (locked to the X slider 20), and is housed and disposed within the Z slider 50. From this point of view, it is understood that since there is no need to provide a plurality of hanging springs around each slider as in the conventional tracer, the structure is simple and the size and weight can be reduced. Moreover, the coil spring 72 is Z
Since it is only necessary to hold the weight of the slider 50 and the measuring element 58, the urging force can be relatively weak, and the measuring force can be reduced. Furthermore, since it can be made short, it is configured to reduce variations in characteristics due to deformation.

Next, the action will be explained.

In a normal state where the probe 58 (59) is not in contact with the workpiece, the wire spring 63 forming the XY origin return means 61 is aligned with the Z axis, so the X slider 2
The 0 and Y sliders 40 are stationary at predetermined positions relative to the base 10. Further, since the Z slider 50 is weight balanced by the coil spring 72 forming the Z origin return means 71, it is kept stationary at a predetermined position in the Z-axis direction with respect to the X slider 20, that is, the base body 10. Therefore, the probe 58 (stylus 59) attached to the Z slider 50 is held at the origin, which is one intersection of the X, Y, and Z axes.

Here, when the stylus 59 is brought into contact with the surface of the workpiece (not shown) and moved relatively, the X slider 20 moves in the X-axis direction while holding the Z slider 50 due to the pressing force on the stylus 59 in the X-axis direction. do.
Since the slide member 31 is fitted into the hollow portion 15 of the base body 10, it does not move itself in the Z-axis direction but moves smoothly via the air bearing. The measuring force in this case is equal to the restoring force of the wire spring 63 forming the XY origin return means 61. Also, the stylus 59 is
When a pressing force in the axial direction is applied, the Y slider 40 moves in the Y-axis direction via the Z slider 50 and the X slider 20. Slide member 4 of this Y slider 40
6l and 46r are also fitted into the hollow part 15 of the base body 10, and the sliding surfaces 43l and 43r are engaged with the guide surfaces 14l and 14r of the base body 10, so that the Y slider 40 moves in the Z-axis direction and the X-axis direction. is immovable. In this case, in the present invention, the X slider 2
Since the X slider 2 and the Y slider 40 are directly supported on the base 10 without being stacked,
0 also moves integrally with the Y slider 40 in the Y-axis direction. The measuring force in the Y-axis direction is also measured using the XY origin return means 61.
is equal to the restoring force of the wire spring 63. Next, the stylus 59
When a pressing force is applied in the Z-axis direction, the Z slider 50
moves within the X slider 20 in the Z-axis direction while compressing the coil spring 72, which is the Z origin return means 71.
Both sliders 20 and 50 are prevented from rotating by their own square shapes, and the X slider 20 and Y slider 40 are supported so as not to be movable in the Z-axis direction in a plane parallel to the base 10, so that the Z slider 5
0 moves only in the Z-axis direction.

Here, the amount of movement of the X slider 20 is
2,83, the amount of movement of the Y slider 40 is determined by the Y sensor 8
5, 86 and the Z slider 50 are detected by Z sensors 88, 89, and as a result, the displacement detecting means 80 can detect the shape of the workpiece surface that the stylus 59 contacts as an electrical signal.

Then, when the pressing force in the Z-axis direction is removed, the Z slider 50 is moved by the coil spring 72 (Z origin return means 7
The restoring force of 1) returns the stylus 59 (stylus 58) in the Z-axis direction (downward in the figure) and returns to the Z origin. Similarly, when released from the pressing force in the X-axis direction,
The slider 20 is connected to a wire spring 63 (XY origin return means 6
The restoring force of 1) causes the Y slider 40 to move within the hollow portion 15 of the base body 10 and return to the X origin, and the Y slider 40, released from the pressing force in the Y axis direction, returns to the Y origin. In this way, the measuring element 58 (stylus 59) is moved in three orthogonal axes directions by the function of the neutral position holding means 60 and returned to and held at the X, Y, and Z origin.

However, according to this embodiment, the X slider 20
and the Y slider 40 directly and slidably supported on a common base without stacking them, and the XY origin return means 61 and Z that form the neutral position holding means 60.
Since the origin return means 71 is accommodated within the slider, the overall structure can be made extremely small and lightweight.

Further, the X slider 20 and the Y slider 40 are arranged on parallel surfaces 16 that are spaced apart from each other in the Z-axis direction of the base body 10.
Since it is fitted and directly supported within the hollow portion 15 surrounded by u and 16d, the dimension in the Z-axis direction can be significantly shortened (downsized). Also,
Since both sliders 20 and 40 slide on the same planes 16u and 16d and are regulated in position in the Z-axis direction, there is little interference and high accuracy and uniform directionality can be achieved. This also means that the sliders and their moving structures are easy to process and assemble.

In addition, since it has a stable structure in which the X slider 20 and Y slider 40 are directly supported on the base 10,
The Z slider 50 can be stably supported by the X slider 20 with good followability, and the Z slider 5
0 Z-axis direction movement does not affect the posture of the X slider 20 and/or the Y slider 40. High precision can also be achieved from this point of view.

Further, since the Z origin return means 71 is accommodated and disposed within the Z slider 50, each slider 20, 4
Compared to the conventional structure provided on the outside of 0.50, the dimensions in the X-axis direction and the Y-axis direction are shortened (miniaturized), and together with the shortening and smallness in the Z-axis direction, the size and weight are extremely reduced. I can do it. At the same time, the coil spring 72 forming this means 71 only needs to hold the load of the Z slider 50 and the probe 58, so it becomes a weak biasing force, and the measuring force can be reduced. Moreover, since the coil spring 72 has a single spring structure arranged on the Z-axis, it does not cause deviation errors in the X-axis and Y-axis directions when moving in the Z-axis direction, so the tracer as a whole can be highly accurate. It is possible to further improve the

Furthermore, based on the direct support structure of the X slider 20 and Y slider 40 to the base body 10, the wire spring 63 forming the XY origin return means 61 can be shortened, which not only reduces the variation in characteristics due to spring deformation, but also The restoring force for moving the sliders 20, 40 can be reduced, and the measurement force can be set small.
From this point of view as well, it is possible to achieve small size, light weight, stable characteristics, and high precision. It is also possible to trace soft materials such as plastic products.

Furthermore, the biasing forces of the XY origin return means 61 and the Z origin return means 71 are close to each other, and both have small dimensions, so there are fewer natural vibration problems due to imbalance between the two, and the natural frequency of the tracer itself is Since it can be made larger based on the reduction in size and weight, it is possible to eliminate errors caused by resonance with vibrations of coordinate measuring machines, etc. Further, when trying to make the sliding starting point uniform, etc., there is an effect that it is easy to introduce a viscous liquid or mechanical friction means. Simplification and stable operation of the entire neutral position holding means 60 are guaranteed.

Furthermore, the X slider 10 of the Z slider 50
Since the sliding guidance to and the sliding guidance of the X, Y sliders 20 and 40 to the base body 10 are performed via air bearings, the sliding resistance can be extremely small. Furthermore, only two air pipes 90 and 91 are required.

In the above embodiment, the Z slider 50 is provided at the lowest position with respect to the base body 10, but the point is that the hollow portion 15 is surrounded by a parallel plane separating the X slider 20 and the Y slider 40 in the Z-axis direction. For convenience, the base body 10 can be placed in two stacks.
The Z slider 50 is placed at the lowest position, and the X slider 20 and Y slider 40 are placed on the Z slider 5.
It is also included in the present invention to support it through a second substrate divided into two parts. However, if the structure is as in the above embodiment, the Z origin return means 71 can be made smaller.

Further, although the Z slider 50 is supported by the X slider 20, it may be supported by the Y slider 40. Similarly, although the tip 65 (ball 66) of the wire spring 63 forming the XY origin return means 61 is engaged with the X slider 20, it can also be implemented as a structure in which it is directly engaged with the Z slider 50.

Furthermore, the displacement detection means 80 may be of other types such as electromagnetic type or electrostatic type instead of photoelectric type.

〔Effect of the invention〕

As is clear from the above explanation, the structure is such that the X slider and Y slider are directly supported on the base and slide in the same plane, providing a small and lightweight surface shape measurement tracer with excellent directionality and responsiveness. can.

[Brief explanation of the drawing]

The figures show an embodiment of the surface shape measurement tracer according to the present invention, with FIG. 1 being a cross-sectional front view and FIG.
FIG. 3 is an overall plan view, and FIGS. 4 to 7 are schematic exploded perspective views of each element of the surface shape measurement tracer. FIG. 4 is a base body, and FIG. Y slider, Figure 6 shows X slider,
FIG. 7 shows the Z slider and part of the X slider, respectively. DESCRIPTION OF SYMBOLS 10... Base body, 14l, 14r... Guide surface forming parallel side surfaces, 15... Hollow part, 16u, 16
d... Guide surface forming a parallel surface, 20... X slider, 31... Slide member that is a part of the X slider, 40... Y slider, 46l, 46r...
A slide member that is part of the Y slider, 50...
Z slider, 58... Measuring tip.

Claims (1)

[Claims] 1. A measuring element supported movably in three orthogonal axes directions via an X slider attached to a base fixed to a movable body of a measuring device, a Y slider, and a Z slider is attached to a workpiece surface. In the surface shape measurement tracer that detects the surface shape of a workpiece as an electric signal while contacting and sliding along the surface, the Y slider is supported on the base body so as to be movable in the Y-axis direction and immovable in the X and Z-axis directions; The X slider is supported on the base body and the Y slider so as to be movable in the X-axis direction and immovable in the Z-axis direction, and the
The Z slider having a hollow cylindrical portion extending in the axial direction is provided so as to be movable in the Z-axis direction, and the base end is fixed to the base body so as to be adjustable in the Z-axis direction, and the distal end is inserted into the hollow cylindrical portion. An XY origin return means formed of a wire spring that returns the X and Y sliders to the origin is provided, and a Z origin return means is provided that is housed in the hollow cylindrical portion and formed of a coil spring that returns the Z slider to the origin. A tracer for surface shape measurement featuring: