JPH0129403B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a first member having a scale and a displacement detection unit, such as a measuring machine such as a two-dimensional measuring machine, a three-dimensional measuring machine, a shape measuring machine, or a machine tool. The present invention relates to a scale protector used in equipment in which a second member having a second member is movable relative to each other.

Generally, in this type of equipment, in order to measure the amount of relative displacement between the first and second members with high precision, a highly precisely processed scale such as a glass scale, magnetic scale, metal plate reflective scale, etc. is used. In order to maintain high accuracy, it is necessary to protect the surface of the scale. That is, if damage occurs due to oil adhesion due to contact by an operator, accumulation of iron chips, dust, etc., or damage due to contact with tools, etc., the desired measurement accuracy cannot be obtained.

For this reason, conventional equipment is provided with a scale surface protection device. However, conventional devices have problems such as a decrease in measurement accuracy due to an increase in sliding resistance, and difficulty in assembly and disassembly. For example, according to Japanese Utility Model Publication No. 39-32506 and Japanese Utility Model Publication No. 56-35765, a single strip member is used, and this strip member is laid along the longitudinal direction of the rack or scale. A structure is shown in which the belt-like member is placed through a slider or slider that is movable relative to the scale, and is brought into close contact with the surface of the scale storage case or the scale surface by the tension applied when passing the belt-like member. There is. However, since these known structures use a band-like member that is integrated with the case or scale, it is necessary to increase the tension in order to strengthen the adhesion, which increases the sliding resistance of the slider and increases the , which caused a return error when reversing the direction of movement. In addition, the thickness of the slider, etc. in the direction perpendicular to the thickness of the strip member is increased, making the device larger and the structure more complicated, which not only makes it inconvenient to assemble and disassemble, but also makes it difficult to inspect the scale. It was becoming an inconvenience. Furthermore, there is also the problem that a gap may be created between the band member and the case due to expansion and contraction due to temperature changes, separation due to vibration, etc., and movement of the slider may be inhibited due to sagging of the band member.

It is an object of the present invention to effectively protect a scale, reduce sliding resistance during relative movement between a first member having a scale and a second member having a displacement detection unit, and facilitate assembly and disassembly thereof. is to provide easy scale protector.

The present invention constitutes a scale protection device by a band-shaped constant pressure spring whose one end is attached to a first member having a scale, and whose other end can be wound up by a winding device provided on a second member, As a result, when the first and second members move relative to each other, the constant pressure spring is stretched along the scale or is wound up by the winding device to reduce sliding resistance, and this winding structure allows the constant pressure spring to be stretched along the scale or wound around the winding device. This object is achieved by simplifying the overall structure by not penetrating the two members and making assembly and disassembly easier.

An embodiment in which the present invention is applied to a coordinate measuring machine will be described below with reference to the drawings.

In the overall configuration diagrams shown in FIGS. 1 and 2, a plurality of screw holes 2 for mounting the object to be measured are provided on the upper surface of a base 1 consisting of a stone surface plate, and on the front and rear end surfaces perpendicular to the longitudinal direction. Each handle 3 is provided with an L-shaped cross section. On both left and right sides of this base 1, there are two guide rails 4, 5 as a first member.
are attached via a plurality of implantation shafts 6, and these guide rails 4, 5 are formed longer than the length in the longitudinal direction (Y-axis direction) of the base 1.
It is provided below the upper surface of the base 1, parallel to the upper surface, and protruding from the side surface of the base 1. Further, both guide rails 4 and 5 are made by cutting down both sides of the cylinder in parallel so that the cross-sectional shape perpendicular to the longitudinal direction has a substantially oval shape consisting of a circular arc portion and a straight portion (see Fig. 3). On the other hand, on the outer surface of the guide rail 4 at the front in FIG. 7
is attached with the scale surface perpendicular (see FIGS. 3 and 4), and the surface of this scale 7 is protected by a scale protection device 8, which will be described later.

A probe support member 9 as a second member is supported by the guide rails 4 and 5 on both sides so as to be able to reciprocate in the Y-axis direction along the longitudinal direction of both the guide rails 4 and 5. This gauge head support member 9 includes a pair of support columns 10, a dimension regulating shaft 11 fixedly attached between the support columns 10, and a pair of support columns 10 attached via a position adjustment block 12 between the upper portions of the support columns 10. , an X slider 14 slidably supported along the pair of X axes 13 , a spindle support 15 tiltably attached to the X slider 14 , and a spindle support 15 attached to the X slider 14 so as to be tiltable. A spindle (Z
The gauge head 17 is removably supported at the lower end of the spindle 16 of the gauge head support member 9, and the workpiece 1 of the gauge head 17 is
A displacement detector 33 (to be described later), which is built into the scale 7 and the lower part of the column, detects the three-dimensional displacement with respect to the scale 7.
(See Figure 4) Y-direction displacement amount, the X-axis 13
A scale (not shown) and X slider 1 provided in
4 and a displacement detector (not shown) provided in the spindle 16 and a displacement detector (not shown) provided in the spindle 16 and the spindle support 15. It is becoming more and more like this.

Shock absorbers 20 are attached to both ends of the one guide rail 4, and
Stoppers 21 having a larger diameter than the guide rail 5 are attached to both ends of the other guide rail 5, and these shock absorbers 20 and stoppers 21 prevent the probe support member 9 from falling off the guide rails 4 and 5. There is.

3 and 4 show the detailed structure of the engagement portion between the support column 10 and the guide rail 4 at the lower part of the support column 10 of the probe support member 9. In these figures, there is a support block 22 at the bottom of the column 10.
A pair of upper and lower rollers 23 are provided on the support block 22 and are rotatable via a support shaft 24, which roll in contact with the outer surface of the guide rail 4, that is, the flat surface on which the scale 7 is attached. is supported by A spacer 25 as a first cylindrical member is interposed between the pair of rollers 23 on the outer periphery of the support shaft 24, and a pincushion-shaped collar 26 as a second cylindrical member is disposed on the outer periphery of the spacer 25. The spacer 25 maintains the dimension between both rollers 23, and the spool-shaped collar 26 made of a low-friction material such as fluororesin
This maintains the smooth rotation of the roller 23. At this time, the support shaft 24, the spacer 25, and the collar 26 constitute a winding device 27. On the outer periphery of the collar 26 of this winding device 27, one end of the scale protection device 8 is attached to the shock absorber 20, and the other end of the scale protection device 8 is attached so as to be able to be wound up. This protection device 8 is composed of a belt-shaped member made of a constant pressure spring wound in a spiral shape. Here, the reduced inner diameter in the free state of the constant pressure spring constituting the protection device 8 is designed to be smaller than the outer diameter of the constant pressure spring winding portion of the collar 26, and the constant pressure spring is automatically wound using the characteristics of the constant pressure spring. I'm starting to get injured.

Further, upper and lower rollers 29 and 30 are rotatably supported on the support block 22 via support shafts 31 and 32, which roll into contact with the upper and lower cylindrical surfaces of the guide rail 4. The guide rail 4 is moved by these rollers 29, 30 and the pair of rollers 23.
The support block 22, ie, the probe support member 9, can be slid smoothly along the guide rail 4 by being held in the 120-degree direction. Further, the roller group consisting of these rollers 29, 30, and 23 is connected to the support block 22, that is, the measuring element support member 9.
One set is provided on each side of the guide rail 4 along the longitudinal direction. In this case, both sides do not necessarily have to mean both ends; in the one shown in FIG. Good too,
In other words, it is sufficient that the support block 22 is provided with at least two sets. Further, in the roller group on the right side in FIG. 4, a spacer 25 as a first cylindrical member is also provided on the support shaft 24 of the upper and lower pair of rollers 23.
and a pincushion-shaped collar 26 as a second cylindrical member are fitted, and these support shafts 24, spacers 25, and collars 26 also constitute a winding device 27. Eventually, the winding device 27 is connected to the support block 2.
Two scale protectors 8 are provided in the longitudinal direction of the guide rail of FIG. It is wound up. Therefore, one end of the scale protector 8, the other end of which is wound up by both winding devices 27, is extended left and right along the surface of the scale 7 attached to the guide rail 4, so as to protect the scale 7. was made,
As the measuring element support member 9 moves along the guide rail 4, one constant pressure spring is stretched, and the other constant pressure spring is wound up by a winding device 27. Further, the constant pressure springs constituting both scale protection devices 8 have substantially equal spring characteristics, so that the measuring element support member 9 can be moved to either the left or the right with substantially the same force.

As shown in the schematic diagram of FIG. 4, the support block 22 includes a displacement detection device which together with the scale 7 constitutes a Y-direction displacement amount detection device for measuring the amount of movement of the probe support member 9 in the Y-axis direction. A unit 33 is provided. This unit 33 includes an index scale 34 in which a scale similar to that of the scale 7 is formed on a transparent plate such as glass, a light emitting element 35 that emits light onto the surface of the scale 7 through the index scale 34, and It is composed of a light receiving element 36 that receives light emitted from the light emitting element 35 and reflected by the scale 7, and the light is transmitted to the light receiving element 36 by changing the amount of received light due to the brightness and darkness of both scales based on the relative movement of both scales 7 and 34. The amount of displacement of the support member 9 in the Y direction can be measured using the generated sinusoidal current. At this time, the optical axes of the light-emitting element 35 and the light-receiving element 36 are arranged in a V-shape, so that the light from the light-emitting element 35 is reflected by the scale 7 and reaches the light-receiving element 36 reliably.

5 and 6 show the detailed structure of the shock absorber 20, and in these figures,
The absorber 20 is configured as follows. That is, a substantially cylindrical slider having an inner circumferential protrusion 37A that is slidably engaged with the end of the guide rail 4 and can come into contact with a step end surface 4B formed at the end of the guide rail 4. 37, a spring receiver 38 that is screwed into the end of the guide rail 4 and whose outer periphery is in almost sliding contact with the inner periphery of the slider 37, and between this spring receiver 38 and the inner peripheral protrusion 37A of the slider 37. and a compression spring 39 which is interposed in and urges the mover 37 to constantly contact the step end surface 4B,
When the measuring element support member 9 is brought into contact with the moving element 37,
By bending the spring 39, the impact received by the support member 9 is reduced.

Further, one end of the scale protector 8 made of a constant pressure spring is held between a bush 40 and a nut 41, and is attached to the shock absorber 2 by a bolt 42.
It is fixed to the mover 37 of 0.

Note that the engagement between the guide rail 5 at the rear left in FIG. (not shown), and the support member 9 as a whole can be smoothly moved in the Y-axis direction.

When measuring the shape, etc. of the object to be measured 18 using this embodiment configured as described above, the lower end of the spindle 16 is held and the measuring head 17 is placed under the cover, just as in conventional three-dimensional measuring machines. The X, Y,
The amount of displacement in the Z-axis direction is detected by the displacement amount detection unit 33 or the like. At this time, the scale 7 is always covered with a protection device 8, and it is effectively prevented from being contaminated by oil or the like or being damaged by contact with tools or the like.

According to this embodiment as described above, there are the following effects. That is, a belt-shaped constant pressure spring with one end wound in a spiral shape is used as the scale protection device 8, and this protection device 8 is placed between both ends of the guide rail 4 having the scale 7 and both sides of the measuring head support member 9. Since two pieces are used, one piece for each type, the scale can be sufficiently protected while maintaining smooth sliding of the measuring piece support member 9. In addition, since both protection devices 8 are configured to have approximately equal characteristics, the support member 9 can be moved approximately equally in any direction, and the load on the support member drive device can be kept constant during automation. This can be advantageous for automation. Furthermore, since the protection devices 8 are provided separately on the left and right sides, there is no need to bypass the displacement detector 33 as in the conventional case, the internal structure can be simplified, and assembly and disassembly can be facilitated. Further, since the winding device 27 is configured using the support shaft 24 of the roller 23 that engages the support member 9 with the guide rail 4, the structure can be simplified and downsized from this point of view as well. The gap with the scale surface can be guaranteed.

Further, since the winding device 27 is provided with a pincushion-shaped collar 26 as a second cylindrical member, by appropriately setting the outer diameter of the winding portion of this collar 26, a protection device consisting of a constant pressure spring can be used. 8 and the scale surface can be set at an appropriate interval. Furthermore, the flange portion of the threaded collar 26 can prevent the constant pressure spring from coming into contact with the upper and lower rollers 23, effectively preventing the generation of noise and malfunction of rotation. Also,
Since the collar 26 is made of a low-friction material,
The collar 26 and the spacer 25 can always rotate smoothly, so even if the winding force of the constant pressure spring is increased, the movement of the support member 9 will not be hindered by the winding of the spring.

Furthermore, since one end of the constant pressure spring, the free end side, is attached to the mover 37 of the shock absorber 20, the mover 37 can be attached to the mover 37 without impairing its function as an absorber.
Can be used to stop rotation. In addition, assembling the support member 9,
When disassembling, there is no need to remove the highly precisely set scale 7, which is convenient, and because the slider 37 is fixed at one end, the open end of the constant pressure spring can be easily wound during disassembly. It does not get completely caught in the device 27, and from this point of view as well, the disassembly work can be carried out smoothly.

Furthermore, since the free end of the constant pressure spring constituting the scale protection member 8 is attached to the scale 7 side and the winding end is attached to the detection unit 33 side, the roller 2
It becomes possible to use the support shaft 24 of 3 and the winding device 2
Not only is there no need to provide a special shaft for 7, but the scale surface will not be damaged by bending of the constant pressure spring that occurs at the free end fixing part. That is, contrary to the embodiment, if the free end is fixed to the detection unit 33 side, the bent part generated at this fixed part will constantly move relative to the scale 7, which may damage the scale surface. It is.

Furthermore, by making the natural winding diameter (initial winding diameter) of the constant pressure spring smaller than the outside diameter of the winding part of the pincushion-shaped collar 26, the constant pressure spring is prevented from sagging due to loose winding, and linearity is maintained. Yes, scale 7
It is possible to effectively prevent damage to etc., and to ensure smooth withdrawal.

In addition, the scale 7 is attached to the guide rail 4 with the scale surface vertical, and the constant pressure spring is also provided parallel to this, so unlike when the scale surface is installed horizontally upward, the sagging of the constant pressure spring causes the scale surface to Further, damage caused by this contact can be effectively prevented.

Note that in implementation, the winding device 27 does not necessarily need to use the support shaft 24 of the roller 23, but if it is used, the above-mentioned advantages can be obtained. Furthermore, either or both of the spacer 25 and the collar 26 of the winding device 27 may be omitted if some noise and poor movement are not a problem. Also,
The constant pressure springs may not be provided equally on the left and right sides, but may have different strengths between the two springs so that the probe support member 9 always returns to one end side of the guide rail 4 in the free state. Further, the scale 7 is not limited to an optical reflection scale, but may be a light transmission scale, an electromagnetic scale, a magnetic scale, a capacitance scale, or even a contact scale, and the detector unit 33 is also used accordingly. Of course, this type of unit is used. Furthermore, in the above embodiments, an example in which the present invention is applied to a three-dimensional measuring machine has been described, but the present invention is not limited to this.
In addition to large measuring machines such as two-dimensional measuring machines and shape measuring machines, small measuring instruments such as calipers, height gauges, and dial gauges, as well as independent length measuring instruments that measure linear movement, such as linear scales ( Trademark), and can also be applied to sliding parts of machine tools, etc. In short, it can be applied to measuring the amount of displacement of two objects that can move relative to each other in a linear direction. Furthermore, the application mode may be such that the guide rail 4 side, which is the first member, is fixed or movable, as long as it can be moved relative to the measuring head support member 9, which is the second member.

As described above, according to the present invention, it is possible to provide a scale protection device that can protect the scale effectively, allows smooth sliding of the first and second members, and is easy to assemble and disassemble. There is.

[Brief explanation of drawings]

Fig. 1 is a partially cutaway perspective view showing an embodiment in which the present invention is applied to a three-dimensional measuring machine, Fig. 2 is a plan view thereof, and Fig. 3 shows a schematic configuration inside the support block of this embodiment. Figure 4 - Enlarged sectional view along the line, No. 4
5 is an enlarged sectional view showing the inside of the shock absorber of this embodiment, and FIG. 6 is a sectional view taken along the line -- in FIG. 5. DESCRIPTION OF SYMBOLS 1... Base, 4... Guide rail as a first member, 7... Scale, 8... Scale protection device,
9... Gauge head support member as a second member, 20...
...Shock absorber, 22...Support block,
23...Roller, 24...Support shaft, 25...First
A spacer as a cylindrical member, 26... a thread-shaped collar as a second cylindrical member, 27... a winding device, 33... a displacement detection unit, 37... a mover.

Claims (1)

[Claims] 1. A scale fixed to a first member, and a scale attached to a second member that is movable relative to the first member to adjust the amount of relative displacement between the first and second members in cooperation with the scale. A protection device for a scale installed in a device equipped with a displacement detection unit for detecting
The scale is attached to the member side, and the other end is capable of being wound up by a winding device provided on the second member side, and expands and contracts along the surface of the scale as the first member and the second member move relative to each other. A scale protection device comprising a band-shaped constant pressure spring. 2. In claim 1, the winding device winds the other end of the belt-shaped constant pressure spring around a cylindrical member rotatably attached to the second member, and uses the winding characteristic of the belt-shaped constant pressure spring to automatically wind the winding device. A scale protector characterized in that it is configured to be removable. 3. The scale protection device according to claim 2, wherein the cylindrical member is rotatably mounted on a support shaft of a roller that is attached to a second member and rolls along the first member. . 4. The scale protection device according to claim 2 or 3, wherein the belt-shaped constant pressure spring has a contracted inner diameter smaller than an outer diameter of the cylindrical member in a free state.