JP2540798Y2 - Torch height detector for thermal cutting machine - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a torch height detecting device for a thermal cutting machine.

[0002]

2. Description of the Related Art In a processing machine equipped with a torch for thermal cutting using plasma, laser, gas or the like, as shown in FIG. 7, a torch holder 3 is fixed to a substrate 2 attached to a processing machine body. The torch 1 is inserted.
A height detector 21 is used to reduce the torch height during the cutting operation, that is, the distance b between the lower end of the torch 1 and the upper surface of the workpiece 10 to a predetermined size. The height detector 21 is fixed to the torch holder 3 so that the lower surface of the detection unit keeps a distance a from the lower end of the torch 1. The detection unit is located at a position offset with respect to the center axis of the torch 1, and moves while keeping a constant distance from the torch 1 as the torch 1 moves.
Then, based on the detection data of the height detector 21, the torch 1
The lower end is always at the optimum height, that is, the lower end of the torch 1 and the workpiece 1
The height of the torch is controlled so that the distance from the zero upper surface becomes b.

[0003]

[Problems to be Solved by the Invention] The torch and the height detector are fixed to the same component (for example, a torch holder) or a component that does not change in relative position, and the relative position is always unchanged. Therefore, the conventional height detecting device has the following problems. (1) Spatter and dross generated during cutting adhere to the height detector near the torch,
This leads to a decrease in detection accuracy and durability. (2) Since the detection position of the height detector is not immediately below the torch but at the position around the torch, when the material to be cut is warped due to thermal strain or the like, the calculation is based on the detection value of the height detector. There is a difference between the torch height and the actual torch height. Therefore, even if the torch height is controlled based on the detection result of the height detector, the torch height is not necessarily set to the optimum torch height. (3) When a part of the material to be cut is cut off, the detection target surface of the height detector may be lost, and the height may not be detected.

[0004] The height detector also has the following problems. (1) In the non-contact type height detector, the detection value level changes when the material of the material to be cut changes. Therefore, it is necessary to adjust the detection value level each time the material changes.
(2) Since the non-contact type height detector can detect the height without directly touching the material to be cut, there is no danger of damaging the material to be cut, but cannot be detected when the detection area of the detection target portion is small. . (3) The contact type height detector directly detects the height by directly contacting the material to be cut, so the detection accuracy is high. However, since the contact height detector is constantly in contact with the material to be cut during the cutting operation, the material to be cut is damaged. Or the contact surface of the detector may be damaged.

The present invention pays attention to the above-mentioned conventional problems, and it is possible to detect the height at a position directly below the torch irrespective of the shape of the material to be cut without spatter, dross, etc. adhering to the height detector. It is another object of the present invention to provide a torch height detecting device at the start of cutting of a thermal cutting machine using a height detector whose detected value level does not change depending on the material of the material to be cut.

[0006]

SUMMARY OF THE INVENTION In order to achieve the above object, a torch height detecting device for a thermal cutting machine according to the present invention comprises a lower end of a slide rod which moves up and down and rotates on a straight line parallel to the torch center axis. A height detector is fixed via an arm, and when the slide rod is lowered and rotated, the height detector moves directly below the torch, and becomes detectable with respect to the material to be cut. When the rod is lifted, the height detector moves so as to avoid laterally above the torch.In such a configuration, the cutting start operation of the torch is performed until the height detector ends the avoiding movement laterally above the torch. Control to stop. As for the specific means for moving the height detector, the actuator and the slide guide are fixed to the substrate to which the torch is fixed via the torch holder in parallel with the torch center axis, and the piston rod end of the actuator and the slide guide slide inside. The leading end of the slide rod to be connected is connected by a connecting plate, and a straight guide groove parallel to the center axis of the slide guide and a spiral guide groove following the groove are provided on the slide guide, and a pin protruding from the slide rod is provided. By sliding in the guide groove, the slide rod interlocking with the expansion and contraction of the actuator moves up and down and rotates. The torch height detector uses a height detector that is provided at the lower end of the detector main body and includes a poppet that can move up and down in the housing and a distance sensor that detects a distance to the upper surface of the poppet. A height detector in which the poppet is biased downward by a coil spring, or a height detector in which the poppet descends by its own weight in the housing, or at least one hole penetrating the poppet parallel to the center axis of the poppet And a height detector in which a tube for introducing compressed air into the housing is connected to the detector body.

[0007]

According to the above construction, the height detector is attached to the lower end of the slide rod which moves up and down and rotates on the center axis of the slide guide, and detects the height when the slide rod is lowered. Since the vessel is placed immediately below the torch, the torch height at the torch center axis can be detected at the start of cutting. Therefore, even when the material to be cut has thermal distortion or the like, it is possible to minimize the detection error due to the distortion. Also, during the cutting operation, the height detector is raised by raising the slide rod, and moves to the upper side of the torch, so that spatter, dross and the like can be prevented from adhering to the height detector.

The height detector uses a distance sensor to detect the distance between the upper surface of the poppet abutting the workpiece and the lower surface of the sensor, so that the advantage of the contact type height detector is utilized. The detection value level does not change due to the material of the material to be cut.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a torch height detecting device of a thermal cutting machine according to the present invention will be described below with reference to the drawings, taking a plasma processing machine equipped with a cutting plasma torch as an example. 1 and 2, a substrate 2 is fixed to a device for vertically moving a torch 1 of a plasma processing machine. A torch holder 3, an actuator 5 for vertically moving a height detector 4, and a slide guide 6 are fixed to the substrate 2. Have been. The torch 1 is inserted into the torch holder 3, and the central axes of the actuator 5 and the slide guide 6 are parallel to the central axes of the torch 1, respectively. The distal end of the piston rod 5a of the actuator 5 and the distal end of the slide rod 6a sliding on the inner periphery of the slide guide 6 are connected by a connecting plate 7, and one end of an arm 8 is fixed to the distal end of the slide rod 6a. The height detector 4 is fixed to the other end of the arm 8 projecting obliquely downward.

[0010] As shown in FIG.
A guide groove 6b parallel to the center axis of the slide guide 6 and a guide groove 6c spirally twisted following this groove are provided.
A pin 6 protruding from the upper outer periphery of the slide rod 6a
d can slide along the guide grooves 6b and 6c. When the pin 6d moves down the guide groove 6c, the slide rod 6a rotates around the center axis of the slide guide 6, and the arm 8 rotates accordingly.
When the pin 6d abuts on the lower end of the guide groove 6c, the height detector 4 reaches the position A in FIG. 1 and its central axis coincides with the central axis of the torch 1. Although not particularly shown, the slide guide 6 is provided with a top dead center detection optical sensor and a bottom dead center detection optical sensor for detecting that the slide rod 6a has reached the top dead center or the bottom dead center.

The actuator 5 operates according to a control signal output from the control unit 9. When the piston rod 5a of the actuator 5 is retracted into the cylinder, the slide rod 6a is retracted into the slide guide 6 while rotating in the direction opposite to the downward movement. Set to position.

In starting the cutting process by the plasma processing machine, it is necessary to set the height of the torch 1 with respect to the workpiece 10, that is, the distance between the lower end of the torch 1 and the upper surface of the workpiece 10 to a predetermined size. Then, the control unit 9 is operated, and the actuator 5 is
Drive. When the actuator 5 is extended by the output signal of the control unit 9, the slide rod 6a connected to the piston rod 5a is also lowered, and when the pin 6d comes into contact with the lower end of the guide groove 6c, the height detector 4 moves below the torch 1. , A, and the central axes of the torch 1 and the height detector 4 coincide.

After moving to the position A, the height detector 4 detects the height of the material to be cut, and inputs the result to a plasma processing machine controller (not shown). Next, the actuator 5 is contracted by the output signal of the control unit 9, and the height detector returns to the position B. During this time, a control signal is output from the control unit 9 to the plasma processing machine control device, and the torch 1 is not operated.

When the top dead center detecting optical sensor detects that the slide rod 6a has returned to the original position, the torch vertical movement device of the plasma processing machine operates, and the substrate 2 starts lowering. Then, the lower end of the torch 1 descends to a predetermined height calculated by the control device based on the detection result of the height detector 4. Thereby, the height of the torch 1 is determined, and the cutting operation by the plasma arc is started. In the present invention, the torch initial height at the start of the cutting operation is set based on the value detected by the height detector, and the torch height control during cutting is performed by the control device.

In this embodiment, the slide guide 6 is provided with the optical sensor for detecting the top dead center and the optical sensor for detecting the bottom dead center. However, the present invention is not limited to this, and the piston rod 5a of the actuator 5 reaches the top dead center or the bottom dead center. A sensor or limit switch for detecting that the operation has been performed may be provided.

Next, an embodiment of the height detector will be described. FIG. 4 is a partial sectional view of the height detector according to claim 5.
The detector main body 11 of the height detector 4 and the housing 12 are connected by a screw joint 13, and a spacer 14 is sandwiched between the detector main body 11 and the housing 12.
Inside the housing 12, a poppet 15 having a flange on the outer periphery, a sleeve 16 fitted on the upper side of the flange of the poppet 15, an end face of the sleeve 16 and the screw joint 1
A coil spring 17 is provided between the housing 3 and the outer periphery of the flange of the poppet 15 and the outer periphery of the sleeve 16 so as to freely slide on the inner periphery of the housing 12. A distance sensor 18 is inserted into a hole provided in the axis of the threaded joint 13, and a lower end surface of the distance sensor 18 is fixed at a fixed interval from an upper end surface of the poppet 15. .

When the height detector 4 descends directly below the torch 1 and comes into contact with the upper surface of the workpiece 10, the poppet 15 is pushed up together with the sleeve 16 against the tension of the coil spring 17, and the distance sensor 18 is turned on. The distance from the upper surface of the poppet 15 is detected and input to the control device.

FIG. 5 is a partial sectional view showing an embodiment of the height detector according to claim 6. In this embodiment, the coil spring shown in FIG. 4 is omitted, and the poppet 15 and the sleeve 16 are lowered by their own weight. Other operations are the same as those of the fifth embodiment (see FIG. 4).

FIG. 6 is a partial sectional view showing an embodiment of the height detector according to claim 7. The poppet 19 is provided with at least one through hole 19 a parallel to the central axis, and the tube 20 introduces compressed air into the space inside the housing 12.
The compressed air is blown out from the through hole 19a of the poppet 19, and is blown onto the upper surface of the material 10 to be brought into contact with the poppet 19, thereby scattering foreign substances attached to this surface. When the poppet 19 comes into contact with the upper surface of the workpiece 10, the through hole 19a
The compressed air urges the poppet 19 downward. The distance detection by the distance sensor 18 is the same as that of the fifth embodiment.

[0020]

As described above, according to the present invention, the height detector is attached to the vertical movement and rotation mechanism, and the height is detected immediately below the torch only when detecting the distance between the torch and the workpiece. The height detector is moved upward during the cutting operation, so that an accurate distance that is not easily affected by thermal distortion of the material to be cut can be obtained. And no spatter or the like adheres. Therefore, it is possible to maintain the detection accuracy of the height detector for a long period of time and improve the durability.

The height detector has a structure in which the poppet is brought into contact with the material to be cut and the distance to the upper surface of the poppet is detected by a distance sensor. Therefore, the detection value level is independent of the material of the material to be cut. It is constant. In addition, detection can be performed regardless of the size of the detection target portion, and a high-precision height detector having both advantages of the conventional contact-type detector and non-contact-type detector can be obtained.

[Brief description of the drawings]

FIG. 1 is a partially omitted front view of a part around a torch of a plasma processing machine equipped with a torch height detecting device.

FIG. 2 is a partial top view around the torch shown in FIG. 1;

FIG. 3 is a partially omitted front view of a slide guide.

FIG. 4 is a partial cross-sectional view of a height detector according to claim 5;

FIG. 5 is a partial sectional view of a height detector according to claim 6;

FIG. 6 is a partial sectional view of a height detector according to claim 7;

FIG. 7 is a front view of a portion around a torch of a processing machine for thermal cutting provided with a torch height detector according to a conventional technique.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Torch 2 Substrate 3 Torch holder 4, 21 Height detector 5 Actuator 5a Piston rod 6 Slide guide 6a Slide rod 6b, 6c Guide groove 6d Pin 7 Connecting plate 8 Arm 11 Detector main body 12 Housing 15, 19 Poppet 17 Coil spring 18 Distance sensor 19a Through hole 20 Tube

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Atsushi Izui 1200 Manda, Hiratsuka-shi, Kanagawa Pref. Komatsu Ltd. Research Laboratory (56) References Hikaru 1-151973 (JP, U)

Claims (7)

(57) [Scope of request for utility model registration] 1. A height detector is fixed to a lower end of a slide rod that moves up and down and rotates on a straight line parallel to the torch center axis via an arm, and detects a height when the slide rod moves down and rotates. A torch height detecting device for a thermal cutting machine, wherein a height detector moves to a position directly beneath the torch, and a height of the slide rod rises when the slide rod rises. 2. The thermal cutting machine according to claim 1, wherein when the height detector is located at a position other than the position above and below the torch, the cutting start operation of the torch is stopped. Torch height detector. 3. An actuator 5 is mounted on a substrate 2 to which the torch 1 is fixed via a torch holder 3 in parallel with the torch center axis.
And the slide guide 6 is fixed, and the distal end of the piston rod 5a of the actuator 5 and the distal end of the slide rod 6a that slides in the slide guide 6 are connected by a connecting plate 7, and a linear guide parallel to the center axis of the slide guide 6 is provided. A groove 6b and a spiral guide groove 6c following the groove are provided in the slide guide 6, and a pin 6d protruding from the slide rod 6a slides in the guide groove 6b, 6c, thereby interlocking with expansion and contraction of the actuator 5. The torch height detecting device for a thermal cutting machine according to claim 1, wherein the sliding rod (6a) that moves and moves vertically. 4. A height detector 4 provided at a lower end of a detector main body 11 and comprising a poppet 15 which can move up and down inside a housing 12 and a distance sensor 18 which detects a distance to an upper surface of the poppet 15. The torch height detecting device for a thermal cutting machine according to claim 1, wherein: 5. The torch height detecting device for a thermal cutting machine according to claim 4, wherein said poppet is a height detector urged downward by a coil spring. 6. The torch height detecting device for a thermal cutting machine according to claim 4, wherein the poppet is a height detector which descends in the housing by its own weight. 7. The height detector according to claim 4, wherein at least one hole penetrating the poppet is provided parallel to the center axis of the poppet, and a tube for introducing compressed air into the housing is connected to the detector main body. A torch height detector for a thermal cutting machine.