JPH0330817Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to an automatically driven three-dimensional measuring machine, and in particular a safety device that is activated when there is a difference between the actual mode and the preset mode by a program. This invention relates to a three-dimensional measuring machine equipped with a three-dimensional measuring machine.

[Background technology and its problems]

The object to be measured placed on the stage and the detector attached to the tip of a vertically movable spindle are moved relative to each other in three dimensions, and the two are brought into contact with each other and involved. 2. Description of the Related Art Three-dimensional measuring machines are known that measure the shape, dimensions, etc. of an object to be measured based on the amount of relative displacement. In recent years, automatic drive type three-dimensional measuring machines have become popular in which the relative movement is automatically performed by a computer program to improve the efficiency of measurement work and save labor.

Conventionally, when an automatically driven three-dimensional measuring machine employs a touch signal type probe as a detector, the object to be measured is determined based on theoretical calculations or data collected by scanning along a reference object. The relative movement locus and speed with respect to the probe were programmed, and actual measurements were performed by placing and fixing the object to be measured on a stage and then automatically driving it according to the program. When the object to be measured and the detector become involved before the standard target value of the program, or when the object and the detector become involved beyond the standard target value, or when the relative overrun of the detector to the object to be measured exceeds a certain amount. When this occurs, the relative movement is stopped. The overrun tolerance is set based on the structure of the detector and is generally several mm.

In any case, considering the main body structure, drive mechanism, inertia, etc. of the coordinate measuring machine, when the touch signal is transmitted from the touch signal type probe, the relative movement is decelerated or stopped. Or it was configured to slow down and then stop.

However, even if measures are taken to stop the device when the allowable overrun amount is exceeded, or to decelerate and stop the device when a touch signal is transmitted, practical problems still remain. In other words, if the measurement surface of the object to be measured is not near the predetermined target value, the detector will collide with the measurement surface during high-speed operation before switching to low speed, which will not only make it impossible to collect the measurement data but also prevent detection. In the case of soft measuring objects such as children or plastics, there is a problem that the measuring object may be damaged. On the other hand, if the target value is exceeded after the low speed changeover but still does not reach the measurement surface, time will be wasted unnecessarily, resulting in a problem that work efficiency will be reduced.

If the object to be measured is not fixed to the stage in the same three-dimensional position as the previous measurement, the above-mentioned inconvenience will be noticeable and occur in many places, so in order to avoid this, extremely sophisticated mounting jigs are required. must be prepared for each object to be measured, and the work of installing and removing them also imposes a heavy economic burden.

When the object to be measured is set on the stage far from the predetermined position, the structure of the measuring machine other than the detector will collide with the object to be measured, so the structure of the measuring machine will absorb absorption characteristics such as overstroke of the detector. Since there is no such thing, the damage will be significant.

There are various types of automatically driven three-dimensional measuring machines, especially those that are not configured to automatically measure all measurement points on the object to be measured.
Or there are things that don't operate that way. For example, there is a system in which the same program is used to drive an approximate object to be measured, and the remainder is corrected using data measured by an auxiliary measuring device instead of a detector.

During automatic operation of this type of coordinate measuring machine, the measuring machine structure collides with the measuring worker, or the worker is caught between the measuring machine structure and the object to be measured, which not only causes damage to the equipment, but also causes damage to the machine. There were problems with worker safety measures.

In addition to the above, accidents involving contact with measuring equipment structures and collisions can occur, for example, when other long parts are accidentally protruded into the measuring range when being carried in, or when someone other than the measuring worker looks into the measuring equipment. also occurs.

[Purpose of invention]

This invention solves each of the above problems using a three-dimensional measuring machine using NC.
Unlike machine tools, where the drive is controlled toward a machining target value, it is special in that the drive is controlled toward a so-called guideline target value that has a certain width that includes the true value to be measured. having sex,
In addition, the measurement accuracy is in μm and the measurement force is 50g, for example.
The measurement conditions are extremely sophisticated, and the object to be measured and the structure of the measuring machine undergo three-dimensional relative movement, and this relative movement occurs at a location that protrudes from the base. This was done with the recognition that it is caused by the characteristics of
The present invention was developed to equip an automatically driven three-dimensional measuring machine with a safety device that detects an abnormality before the detector is activated and takes specific action.

The purpose of this invention is to avoid the possibility that an object to be measured is set far from the specified position on the stage, or a measuring worker or other person who acts carelessly touches or collides with the spindle, or that the object to be measured and the spindle are If an unexpected situation occurs that is not planned for the program, such as a measurement worker being caught between the equipment, the system will detect this and stop automatic operation to prevent further situations, ensuring the safety of workers, equipment, etc. An object of the present invention is to provide an automatically driven three-dimensional measuring machine that can ensure the following.

In addition, the purpose of this invention is to detect not only when a foreign object such as an object to be measured collides with the spindle with a large impact force, but also when it lightly contacts or reaches the point of contact, thereby making it possible to detect abnormal situations. The purpose of the present invention is to provide an automatically driven three-dimensional measuring machine equipped with a safety device that can perform a wide range of operations.

[Means and actions for solving problems]

Therefore, the automatic drive type three-dimensional measuring machine according to the present invention consists of a measuring object placed on a stage, and a detector attached to the tip of a spindle that is supported vertically displaceably on the main body structure. In an automatic drive type three-dimensional measuring machine that measures the shape, dimensions, etc. of the object to be measured based on the amount of relative movement and displacement when both are involved, the tip side of the spindle and the main body are A light emitter on one side of the structure,
On the other hand, a light receiver that receives the light beam from the light emitter is installed covering at least four sides of the spindle so that the light beam is in the longitudinal direction of the spindle, and the light receiver emits an output when a foreign object blocks the light beam. The apparatus includes a detection device connected to the device, and an emergency stop device for forcibly stopping the relative movement using an output signal from the detection device.

In the above, the four directions are the four directions in the three dimensions, for example in the horizontal direction.

A switching action occurs when the foreign object blocks the light beam, and as a result, the emergency stop device urgently stops the drive device that causes the object to be measured and the detector to move relative to each other based on the output signal from the detection device. let This emergency stop operation is performed when a foreign object blocks the light beam, and can be realized regardless of the magnitude of the collision force between the foreign object and the spindle, or whether or not there is a collision.

By providing a light emitter and a light receiver so as to cover four directions in the three-dimensional horizontal direction of the spindle, it becomes possible to discriminate the direction of the collision, etc.
This not only stops the drive but also
It is also possible to move the spindle backward in the direction opposite to the direction in which the collision or the like occurred.

〔Example〕

FIG. 1 is an overall perspective view of a coordinate measuring machine according to this embodiment. A stage 2 is disposed on the base 1 so as to be movable in the Y-axis direction, and cross beam members 4 are disposed across the top of columns 3 fixed to the left and right sides of the base 1. A slider 5 is provided on the cross beam member 4 so as to be slidable in the X-axis direction, and a spindle 7 is supported on a spindle support member 6 integrated with the slider 5 so as to be movable in the vertical direction, that is, in the Z-axis direction. .
A detector 8 is attached to the lower end of the spindle 7, and in this embodiment, the detector 8 is a touch signal type probe that outputs a touch signal by contacting a measurement object 9 placed and fixed on the stage 2. It's getting old.

By moving the stage 2 with respect to the base 1, the detector 8 and the object to be measured 9 are moved relative to each other in the Y-axis direction, and by moving the slider 5 with respect to the crossbeam member 4, The detector 8 moves in the X-axis direction with respect to the object to be measured 9, and moves toward the spindle support member 6.
When the spindle 7 is displaced relative to the detector 8, a relative movement occurs between the detector 8 and the object to be measured 9 in the Z-axis direction. The amount of relative displacement in the above three orthogonal axes directions is determined by the Y-axis displacement detection device 10 (see Fig. 4) installed between the base 1 and the stage 2, the crossbeam member 4, and the slider 5. X-axis displacement detection device 11, spindle support member 6 and spindle 7 provided between
The displacement is detected by a Z-axis displacement detection device 12 provided between the two, and these detection devices 10, 11, and 12 are composed of optical scales, photoelectric conversion elements, and the like.

Here, the spindle support member 6 is attached to the spindle 7
This is the main body structure of the coordinate measuring machine.

The movement of the stage 2 in the Y-axis direction, the slider 5 in the X-axis direction, and the spindle 7 in the Z-axis direction are carried out by the Y-axis, X-axis, and Z-axis motors 13, 14,
This is carried out by a drive device having a drive source 15, and this drive device is composed of, for example, a feed screw shaft, a pulley, a belt, etc. Each motor 13,
14 and 15 are connected to a CPU (central processing unit) 20 via drivers 16, 17, 18 and a drive control circuit 19.
The CPU 20 is connected to the detection device 10, 1.
The driver 16 has a calculation function for determining the shape, dimensions, etc. of the object to be measured 9 based on the data of the electric signals from the motors 1 and 12, and is provided for each motor 13, 14, 15 according to a preset program. It has a function of outputting an electric command signal to the drive control circuit 19 that controls the motors 17, 18, and thereby controls each motor 13, 14,
The activation timing, number of rotations, rotation speed, etc. of the detector 15 are controlled, and the detector 8 moves automatically while drawing a three-dimensional trajectory with respect to the object to be measured 9, thereby performing two-dimensional measurement.

Here, the program is not set to drive and control the detector 8 toward a fixed target value like an NC machine tool, but instead is set to drive and control the detector 8 toward a so-called reference target value with a certain range. It is set to be driven and controlled, and the true value to be measured is included in this standard target value, so that it can correspond to a different true value for each measurement object 9. Therefore, the spindle 7 and the detector 8 perform different displacements for each object to be measured 9 within the range of the standard target value.

FIG. 2 shows a longitudinal sectional view of the spindle support member 6 around the spindle 7. As shown in FIG. An air bearing 21 that guides movement of the spindle 7 in the Z-axis direction is provided inside the spindle support member 6 as the main body structure of the coordinate measuring machine.
is held by the main body 6B of the spindle support member 6, which is covered with a cover 6A. A flange 22 is attached to the tip or lower end of the spindle 7, and a light emitter 2 is attached to either the upper surface of the flange 22 or the lower surface of the main body 6B vertically opposite to the flange 22.
3 is provided with a light receiver 24 on the other side. A light beam 25 is constantly irradiated between the light emitter 23 and the light receiver 24 in the longitudinal direction of the spindle 7 during automatic operation of the coordinate measuring machine. The light receiver 24 also serves as a photoelectric converter, and the light emitter 23 and the light receiver 2
4. A photoelectric switch 26 is constructed by the light beam 25.

As shown in FIG. 3, the spindle 7 has a rectangular flat cross section with four sides facing in the four horizontal directions of the X and Y axes, and the photoelectric switch 26 has one photoelectric switch on each of these four sides.
26A, 26B, 26C, and 26D are provided, so that the four horizontal directions of the X-axis and Y-axis of the spindle 7 are covered.

Next, we will discuss the effect.

The operation of the CPU 20 based on the program drives the Y-axis, 8 performs a relative three-dimensional movement with respect to the measurement target 9, and this relative three-dimensional movement displacement amount is
Detected by each displacement detection device 10, 11, 12 of the shaft, each displacement detection device 10, 11, 12
The sine wave and cosine wave electric signals from the displacement detection circuit 2
The pulses are divided and waveform-shaped in steps 7, 28, and 29, and a number of pulses corresponding to the amount of displacement are transmitted. The number of pulses is counted by counters 30, 31, and 32, and a count signal is input to CPU 20.
When the detector 8, which is a touch signal type probe, comes into contact with a measurement point of the object 9, a touch signal is transmitted from the detector 8, and this is input to the CPU 20.
As a result, counter 3 when transmitting a touch signal
The shape, dimensions, etc. of the measurement object 9 are calculated in the CPU 20 based on the count value signals from 0, 31, and 32, and the calculation results are displayed on a display device connected to the CPU 20 and recorded in a recording device.

When the detector 8 is connected to the counters 30, 31, 32, when the touch signal is transmitted from the detector 8, the number of pulses counted by the counters 30, 31, 32 is held, and this held The CPU 20 calculates the dimensions, shape, etc. of the measurement object 9 based on the number of pulses.

For example, if the object 9 to be measured is set on the stage 2 far from the predetermined position, or if the operator accidentally touches the 3D measurement area during automatic operation of the 3D measuring machine, the object 9 may move in 3D. A foreign object such as the object 9 to be measured comes into contact with or collides with the spindle 7 . When such a situation outside the program schedule occurs, a photoelectric switch 26 is installed on the spindle 7.
is provided, the object to be measured 9 etc. blocks the light beam 25 of the photoelectric switch 26, and a switching signal related to this blocking is output from the light receiver 24. Light emitter 23 and light receiver 24 of photoelectric switch 26
Since the spindle support member 6 and the spindle 7, which move relative to each other in the Z-axis direction, are installed separately, the light beam 25 is attached to the spindle support member 6 regardless of the amount of protrusion of the spindle 7 from the spindle support member 6. It extends over the entire length of the outer surface of the spindle 7 exposed from 6 in the Z-axis direction,
If a foreign object collides with the outer surface of the spindle 7, the light beam 25 will be surely blocked.

As shown in FIG. 4, an abnormality detection circuit 33 is connected to the light receiver 24 of the photoelectric switch 26, and this abnormality detection circuit 33 is connected to the drive control circuit 19 via an emergency stop circuit 34. Based on the switching signal from the light receiver 24 based on the interruption of the light beam 25, the abnormality detection circuit 33 transmits an output signal such as a pulse,
This output signal is amplified in the emergency stop circuit 34 in order to be inputted to the drive control circuit 19. The drive control circuit 19 controls each motor 13, 14, 15 of the drive device via the drivers 16, 17, 18 using a signal amplified and processed by the emergency stop circuit 34.
, and the movement and displacement of the spindle 7 and detector 8 relative to the measurement object 9 is forcibly stopped.
As a result, the automatic operation of the coordinate measuring machine is stopped urgently, and further abnormal situations are prevented.

In this embodiment, the abnormality detection circuit 33 is a detection device that sends an output signal when the light beam 25 is interrupted, and the emergency stop circuit 34 is the abnormality detection circuit 3.
This serves as an emergency stop device for stopping the drive device in response to an output signal from the sensor 3 and stopping the relative movement between the detector 8 and the object to be measured 9. This emergency stop device may be one that directly stops the drive device as in this embodiment, but may also be one that operates a brake device to indirectly stop the drive device.

In addition, the output signal of the abnormality detection circuit 33 is sent to the CPU 20.
The program may be interrupted by inputting the signal to the driver 16, 17, and 18, thereby causing the drive device to stop urgently. You can also do this. In the former case, the CPU
20 also serves as an emergency stop device, and in the latter case, drivers 16, 17, and 18 also serve as emergency stop devices.

In the above, even if a foreign object such as the measurement object 9 collides with the spindle 7 with a large impact force, lightly contacts it, or approaches just before contact, if the light beam 25 is blocked by the foreign object, The drive is stopped, so that a wide range of abnormal situations can be detected.

In addition, since the photoelectric switch 26 performs a switching action when a foreign object blocks the light beam 25, it is not necessary to install the photoelectric switch 26 in a fixed position relative to the spindle 7. The position of the light beam 25 from the outer surface of the spindle 7 can be freely set.

FIG. 5 shows the four photoelectric switches 26A, 26.
An embodiment will be shown in which the electric circuit to which the light receivers 24 of B, 26C, and 26D are connected is used as an abnormality detection and direction discrimination circuit 35. Similar to the abnormality detection circuit 33, this circuit 35 transmits an output signal based on the signal from the photoreceiver 24, and also transmits a photoelectric switch 26A, which is provided on the spindle 7 in alignment with the four horizontal directions of the X-axis and the Y-axis. It is determined which of the photoelectric switches 26B, 26C, and 26D performed the switching action. As a result, it is determined from which direction a foreign object such as the object to be measured 9 has collided with the spindle 7, and the signal from the abnormality detection and direction discrimination circuit 35 is sent to the CPU 20 for processing. As a result, the drive device not only makes an emergency stop, but also moves the spindle 7 backward in the direction opposite to the direction in which the foreign object collided with it, thereby avoiding the spindle 7 and the detector 8 from the abnormal situation. The spindle 7 is moved in the composite direction of the X-axis and the Y-axis until the detector 8 approaches the measurement location on the object 9 to be measured to shorten the measurement time, but after that, the detector 8 comes into contact with the measurement location. Until recently, the spindle 7 was generally moved in either the X-axis or Y-axis direction, so the four photoelectric switches 2 were used to distinguish the direction of collision, etc.
6 is enough.

Note that the photoelectric switch 26 may be arranged as shown in FIG. 6 in consideration of the case where a foreign object such as the object to be measured 9 collides with the spindle 7 while it is moving in the combined direction of the X-axis and the Y-axis. That is, the photoelectric switch 26 is arranged at the four corners of the spindle 7, which has a rectangular planar cross section.
photoelectric switches 26E, 26F, 26G, 26
H is provided in four diagonal horizontal directions of the X and Y axes. When two photoelectric switches 26 (for example, 26E and 26F) are activated at the same time, one photoelectric switch 26 (for example, 26
E) When activated, it is possible to distinguish whether the object to be measured 9 or the like has collided with the spindle 7 from one of the four diagonal directions. The number of photoelectric switches 26 is not limited to four in each of the above embodiments, but may be eight by combining the embodiments shown in FIGS. It can also be applied to cases where the planar cross section is circular.

In the above, when the direction of collision etc. is not discriminated, the light receivers 24 of the respective photoelectric switches 26 are connected in parallel or in series to form an abnormality detection circuit 33 or an electric circuit having a similar function. may be connected to.

The three-dimensional measuring machine shown in Fig. 1 has a detector on the fixed side and an object to be measured on the moving side with respect to movement in the Y-axis direction.
Regarding axial movement and Z-axis direction movement, the detector was on the moving side and the object to be measured was on the fixed side. Three-dimensional measurement can be applied whether the object is fixed or moving, and if necessary, the object to be measured and the detector move relatively three-dimensionally to measure the dimensions, shape, etc. of the object. Any machine is fine. Further, in the above embodiment, the detector was a touch signal type probe that outputs a touch signal by contacting the object to be measured, but the type of detector may be arbitrary. For example, a non-contact detector using a laser beam may be used. It may be.

[Effect of idea]

According to the present invention, if an abnormal situation that is not planned in the program occurs, such as contact or collision between the spindle and the object to be measured or the measuring worker, etc., this will be detected and the automatic operation of the coordinate measuring machine will be stopped immediately. This makes it possible to ensure the safety of workers and equipment, and is effective in putting automatic drive type three-dimensional measuring machines into practical use.

Furthermore, according to the present invention, if a foreign object blocks the light beam, a switching action occurs, so that an abnormal situation can be detected regardless of the degree of collision force between the spindle and the foreign object, or whether there is contact or not, and a wide range of detection is possible.

[Brief explanation of drawings]

Figure 1 is an overall perspective view of the coordinate measuring machine, Figure 2 is a vertical sectional view of the spindle support member around the spindle, Figure 3 is a cross-sectional view of Figure 2, and Figure 4 is a cross-sectional view of the coordinate measuring machine. Block diagram showing electrical configuration, No. 5
The figure is a block diagram of a main part according to another embodiment, and FIG. 6 is a diagram similar to FIG. 3 showing another embodiment regarding the arrangement position of a photoelectric switch using a light emitter and a light receiver. 2... Stage, 6... Spindle support member which is main body structure, 7... Spindle, 8... Detector,
9...Measurement object, 23...Emitter, 24...Light receiver, 25...Light ray, 26...Photoelectric switch, 3
3... An abnormality detection circuit which is a detection device, 34... An emergency stop circuit which is an emergency stop device.

Claims (1)

[Claims for Utility Model Registration] (1) The object to be measured placed on the stage and the detector attached to the tip of a spindle supported movably in the vertical direction on the main body structure in a three-dimensional direction. In an automatic drive type three-dimensional measuring machine that measures the shape, dimensions, etc. of the measurement target from the amount of relative displacement when both are involved,
A light emitter is provided on one of the tip side of the spindle and the main body structure, and a light receiver that receives light from the light emitter is provided on the other side, covering at least four sides of the spindle so that the light beam is in the longitudinal direction of the spindle. and a detection device connected to the light receiver that emits an output when a foreign object interrupts the light beam, and includes an emergency stop device for forcibly stopping the relative movement with an output signal of the detection device. Automatically driven coordinate measuring machine with configured safety equipment. (2) Utility Model Registration An automatically driven three-dimensional measuring machine as set forth in claim 1, wherein the four directions are four directions in the three-dimensional horizontal direction.