JPH044172Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a vertical axis safety device in a measuring machine. Specifically, in a measuring machine equipped with at least one of an air bearing device that reduces the sliding resistance of the vertical axis against the main body, and an air balance device that reduces the load due to the vertical axis's own weight, vertical It relates to a safety device that prevents damage to shafts and other parts, as well as various dangers.

[Background technology and its problems]

For measuring machines such as two-dimensional or three-dimensional measuring machines, which have a vertical shaft with a measuring head that can be raised and lowered vertically with respect to the main body, the vertical shaft is An air bearing device is installed to reduce the sliding resistance against the main body.
It is known that an air balance device is installed to reduce the load due to the vertical shaft's own weight.

However, in such a device that uses air pressure to smoothly move the vertical axis up and down, various problems occur when the supplied air pressure falls below a specified pressure.

For example, in the former type of air bearing device, if the supply air pressure decreases, the load capacity of the air bearing device decreases, so if the vertical shaft is raised or lowered in this state, there is a risk of damage to the vertical shaft or the air bearing device. arise.

Furthermore, in the latter air balance device, when the supply air pressure decreases, the holding force of the air balance device, that is, the air pressure that supports the vertical shaft's own weight decreases, causing the vertical shaft to fall. The vertical axis fall is
This problem not only causes damage to the measuring device and probe, but also poses a danger to workers.

Therefore, various safety devices have been proposed to prevent the vertical shaft from moving up and down in response to a drop in supply air pressure.
For example, as in Japanese Patent Application Laid-Open No. 61-54410, a locking member having a plurality of locking holes at a constant pitch along the vertical axis is provided, and the locking member is locked on the vertical shaft. There is a structure in which a lock pin inserted into the hole is provided so as to be movable back and forth, and when the air pressure drops below a specified pressure, the lock pin is projected into the locking hole of the locking member by actuation of a cylinder.

However, with this structure, when the cylinder operates, if the lock pin is not in a position that corresponds to the locking hole of the locking member, the vertical shaft will fall naturally and the lock pin will not come to the position that corresponds to the locking hole. Since it is not possible to prevent the vertical shaft from rising and falling, it takes time from the decrease in air pressure until the vertical shaft is stopped from rising and falling. Further, with such a structure, there is a problem in that it is not possible to reliably prevent the vertical axis from moving up and down, and the overall size of the device increases.

[Purpose of invention]

The purpose of the present invention is to eliminate such conventional drawbacks and provide a vertical axis safety device for a measuring machine that is small, can reliably prevent the vertical axis from moving up and down, and has excellent responsiveness. It is in.

[Means and actions for solving problems]

Therefore, the present invention includes a vertical shaft that is supported vertically vertically and has a measuring head, and an air bearing device that reduces the sliding resistance of this vertical shaft with respect to the main body, and the load due to the vertical shaft's own weight. A measuring machine equipped with at least one of an air balance device for reducing the noise, a rack provided on the vertical axis along the vertical axis, a pinion meshed with the rack and rotatably supported on the main body; A disk plate fixed coaxially with the pinion, a pair of clamp members provided on the main body so as to be openable and closable across the disk plate, and the pair of clamp members are attached in the closing direction to sandwich the disk plate. an air cylinder that presses the pair of clamp members in an opening direction against the urging means when air is supplied; and supplying air to at least one of the air bearing device and the air balance device. a solenoid valve inserted between an air source and the air cylinder that normally supplies air from the air source to the air cylinder, and a solenoid valve that switches the solenoid valve when the air pressure from the air source decreases to and control means for cutting off the supply of air to.

Therefore, when the air pressure from the air source decreases, the solenoid valve is switched via the control means and the supply of air to the air cylinder is cut off. clamps and restricts the rotation of the pinion. As a result, the rack meshing with the pinion cannot be moved, thereby preventing the vertical shaft from moving up and down.
In this way, raising and lowering of the vertical axis is reliably prevented.

〔Example〕

Hereinafter, an embodiment in which the safety device of the present invention is applied to the vertical axis of a coordinate measuring machine will be described with reference to the drawings.

Figure 1 shows the external appearance of the three-dimensional measuring machine. Base 1
A table 12 on which the object to be measured is placed is mounted on the top surface of the table 12.
are installed, and a pair of support beams 14A, 14B having Y-axis rails 13A, 13B parallel to each other and extending in the front-rear direction (Y-axis direction) of the table 12 are integrally provided at both ends thereof. There is. The gate-shaped frame 15 is attached to the Y-axis rails 13A, 13B of both support girders 14A, 14B in the Y-axis direction via an air bearing device (not shown), and the slider 16 is attached to the gate-shaped frame 15 via an air bearing device (not shown). is attached to the table 12 in the left-right direction (X-axis direction) with respect to the table 12.
They are each supported movably in the vertical direction (Z-axis direction). Here, the base 11, the gate-shaped frame 15, and the slider 16 constitute a main body that supports the vertical shaft 17 so as to be vertically movable.

During measurement, when the probe 18 is moved in three-dimensional directions and brought into contact with the object to be measured on the table 12, the amount of movement of the probe 18 in each axis direction, that is, the amount of movement of the portal frame 15 in the Y-axis direction, After the amount of movement of the slider 16 in the X-axis direction and the amount of movement of the vertical axis in the Z-axis direction are detected by displacement detectors (not shown),
Displayed digitally.

2 and 3 show specific structures of the portal frame 15, slider 16 and vertical shaft 17.
In the figure, the X-axis beam 1 of the portal frame 15
5A, the slider 16 is supported so as to be movable in the X-axis direction via a plurality of air pads 21 constituting an air bearing device. On the front side of the slider 16, holding frames 22A and 22B that are approximately square in shape when viewed from above are integrally attached vertically, and inside these upper and lower holding frames 22A and 22B, a plurality of air pads 23 constituting an air bearing device are installed. The vertical shaft 17 is supported so as to be movable up and down in the Z-axis direction.

A rack 31 is attached to one side of the vertical shaft 17 along the vertical direction of the vertical shaft 17.
A pinion 38 is engaged with the rack 31 and rotated by a motor 37 that is attached to the slider 16 side and protrudes from a cover 36 that covers the vertical shaft 17. Therefore, when the motor 37 is driven, the pinion 38 rotates, and the vertical shaft 17 is raised and lowered via the rack 31 that meshes with the pinion 38. Further, at a position above the pinion 38, a pinion 32 that similarly meshes with the rack 31 is placed on the slider 1.
6 side, that is, a member 33 connecting the holding frames 22A and 22B via a bearing 34 so as to be rotatable. A disk-shaped disk plate 35 is integrally attached to the pinion 32 coaxially therewith. Therefore, when the vertical shaft 17 moves up and down, the disk plate 35 also rotates at the same time.

On both sides of the disk plate 35, pins 43A and 43B are attached to a support block 42 whose upper end is fixed to the slider 16 via a connecting member 41.
A pair of clamp members 44A and 44B are provided which are supported so as to be openable and closable with each other. The support block 42 has respective clamp members 44A, 44.
Stopper screw 45 for adjusting the opening degree of B
A and 45B are screwed together, and a solenoid valve 47 is attached via a bracket 46.

Each clamp member 44A, 44B is provided with clamp pieces 48A, 48B that clamp both sides of the disk plate 35 in the middle.
Clamp pieces 48A and 48B are clamped by a tension spring 49 as a biasing means stretched between the lower ends of A and 44B.
is constantly biased in the closing direction to sandwich the disk plate 35. A bracket 50 is attached to the lower end of one clamp member 44A, and when air is supplied to this bracket 50, it moves the pair of clamp members 44A and 44B away from each other in the opening direction against the tension spring 49. An air cylinder 51 for pressing is attached.

Figure 4 shows the air supply system. Air source 61
The air is supplied to the air bearing device of each shaft through an air filter, a mist separator 62, and a regulator 63. Air pressure from the regulator 63 is detected by a pressure switch 64. The pressure switch 64 is turned on when the air pressure is above a specified value, and turned off when the air pressure falls below the specified pressure, and provides respective signals to a control circuit 65 serving as a control means. The control circuit 65 is
When the signal from the pressure switch 64 is on, that is, when the air pressure is higher than the specified pressure, the solenoid valve 4
7 and switch it. When the electromagnetic valve 47 is energized, it is switched to a position where air from the air source 61 is supplied to the air cylinder 51;
The structure is such that it can be switched to a position where the supply of air to the air cylinder 51 is cut off when the air cylinder 51 is not energized.

Next, the operation of this embodiment will be explained.

Here, we will consider the case where the measuring instrument is in a floating state, that is, when the pinion 38 is disconnected from the rack 31 and manually operated.

When air pressure equal to or higher than the specified pressure is supplied to the air bearing device of each axis, the pressure switch 64 is on, so the control circuit 65 switches this by energizing the solenoid valve 47, and the air source 6
1 is supplied to the air cylinder 51 through the solenoid valve 47. Then, the piston rod of the air cylinder 51 advances and presses both clamp members 44A, 44B in the opening direction away from each other against the tension spring 49, so that both clamp pieces 48,
The disk plate 35 is released from being held by A8B. Therefore, since the disk plate 35 is in a state where it can freely rotate, the vertical shaft 17 can be freely raised and lowered. At this time, since air pressure equal to or higher than the specified pressure is also supplied to the air bearing devices of each axis, movement in each axis direction can be performed easily.

If the air pressure equal to or higher than the specified pressure is not supplied to the air bearing device of each shaft, the pressure switch 64 is turned off, and the control circuit 65 cuts off the power supply to the solenoid valve 47. Then, the solenoid valve 47 is switched and the supply of air to the air cylinder 51 is cut off. When the supply of air to the cylinder 51 is cut off, the pair of clamp members 44A, 44B are closed by the urging force of the tension spring 49, so that both clamp pieces 48A, 48B clamp both sides of the disk plate 35. Therefore, since the rotation of the disk plate 35 is restricted, the vertical axis 1
7 is prevented from going up and down. Therefore, there are problems associated with raising and lowering the vertical shaft 17 when the air pressure to the air bearing device is lower than the specified pressure, that is, the vertical shaft 1
7 and the air bearing device can be avoided.

Note that if the air pressure above the specified pressure is no longer supplied to the air bearing device while the vertical shaft 17 is being moved up and down by the drive of the motor 37, the pair of clamp members 44A and 44B will close the disk. At the same time as clamping the plate 35,
The motor 37 is automatically stopped by a signal from the control circuit 65.

On the other hand, if the power supply is cut off due to a power outage or the like, for example, the power supply to the solenoid valve 47 from the control circuit 65 is cut off, so that the vertical shaft 17 is similarly prevented from moving up and down. Therefore, the vertical shaft 17 can be prevented from moving up and down even in the event of a power outage or the like. In this case, for example, even if the operation of the air source 61 stops due to a power outage and the air pressure of the air bearing device decreases, the power supply to the solenoid valve 47 is immediately cut off due to the power outage. Therefore, the vertical shaft 17 can be quickly clamped.

Therefore, according to this embodiment, the rack 31 is attached to the vertical shaft 17, and the pinion 32 that meshes with the rack 31 is rotatably supported on the slider 16.
The disk plate 35, which is integrally provided on the pinion 32, is held between a pair of clamp members 44A and 44B when the air pressure to the air bearing device drops below the specified pressure, so that the vertical shaft 17 can be moved up and down. It can be stopped quickly and reliably. Moreover. Since the component parts may be the rack 31, pinion 32, disk plate 35, and clamp members 44A and 44B that clamp them, the overall structure can be made compact and can be stored within the cover 36.

Further, a tension spring 49 is provided that urges the pair of clamp members 44A, 44B in a direction to close each other, and an air cylinder is provided that presses the clamp members 44A, 44B in the direction to open them against the tension spring 49 when air is supplied. 51, and supplies air to the air cylinder 51 when the air pressure is equal to or higher than a specified pressure, thereby clamping members 44A,
44B to allow the vertical shaft 17 to move up and down freely, while cutting off the supply of air to the air cylinder 51 when the air pressure drops below the specified pressure.
As a result, the clamp members 44A and 44B are closed by the tension spring 49 to prevent the vertical shaft 17 from moving up and down, so that the air cylinder 51 can share the air source of the air bearing device.

Furthermore, the solenoid valve 47 that switches the supply of air to the air cylinder 51 is connected to the air source 6 when energized.
1 to the position where air is supplied to the air cylinder 51, and on the other hand, when the power is off, the position can be switched to the position where the supply of air to the air cylinder 51 is cut off. For example, even if the operation of the air source stops due to a power outage and the air pressure in the air bearing device decreases, the vertical axis 17 is immediately prevented from moving up and down due to a power outage. , has the effect of extremely excellent responsiveness.

In addition, in the above embodiment, a coordinate measuring machine having an air bearing device was explained, but in addition to or instead of the air bearing device, the weight of the vertical axis is balanced by air, If the safety device of the present invention is applied to a coordinate measuring machine equipped with an air balance device of various structures to reduce the load, it is possible to reliably prevent the vertical axis from falling. Therefore, damage to the probe and the machine can be prevented, and worker safety can be ensured.

Furthermore, although the above description has focused on a three-dimensional measuring machine, the present invention can be applied to any measuring machine that has a vertical axis that can be raised and lowered in a direction perpendicular to the main body.

[Effect of idea]

As described above, according to the present invention, it is possible to provide a vertical axis safety device for a measuring machine that is small in size, can reliably prevent the vertical axis from moving up and down, and has excellent responsiveness.

[Brief explanation of the drawing]

Fig. 1 is a perspective view of a coordinate measuring machine to which the safety device of the present invention is applied, Fig. 2 is a partially cutaway front view showing the specific structure of the portal frame, slider, and vertical axis, and Fig. 3 is FIG. 4 is a partially cutaway plan view of the same as above, and is a diagram showing the air supply system. 17...Vertical axis, 18...Measuring head, 31...Rack, 32...Pinion, 35...Disc plate, 44A, 44B...Clamp member, 47...
...Solenoid valve, 49...Tension spring, 51...Air cylinder, 65...Control circuit.

Claims (1)

[Claims for Utility Model Registration] (1) An air bearing device and a vertical shaft having a vertical shaft supported vertically so as to be vertically movable and having a probe, and reducing the sliding resistance of this vertical shaft with respect to the main body. In a measuring machine equipped with at least one of an air balance device for reducing the load due to the shaft's own weight, the rack is provided on the vertical shaft along the vertical direction thereof, and the rack is engaged with the rack and rotatably supported on the main body. a pinion, a disk plate fixed coaxially with the pinion, a pair of clamp members provided on the main body so as to be openable and closable with the disk plate in between, and the pair of clamp members sandwiching the disk plate. an air cylinder that presses the pair of clamp members in the opening direction against the urging means when air is supplied; and at least one of the air bearing device and the air balance device. a solenoid valve inserted between an air source that supplies air to one side and the air cylinder and normally supplies air from the air source to the air cylinder; and when the air pressure from the air source decreases, the solenoid valve A vertical axis safety device for a measuring machine, characterized in that it is equipped with: a control means for switching off the air supply to the air cylinder to cut off the supply of air to the air cylinder; (2) Scope of the Utility Model Registration Claim Paragraph 1 provides that the solenoid valve is switched to a position where air from an air source is supplied to the air cylinder when energized, and is switched to a position where air is supplied to the air cylinder when not energized. A vertical axis safety device for a measuring machine, characterized in that it is configured to be switched to a blocking position.