JP7643282B2 - Detection device and machine tool - Google Patents

Description

The present invention relates to a detection device and a machine tool.

There is a detection device that has multiple detection units that detect the ON/OFF of a switch and detects the state of a controlled object based on the detection results of the multiple detection units. Patent Document 1 discloses a control device having a connection unit that allows a control panel to be attached and detached. The control device has a second terminal that connects to a signal line that detects the connection state of the control panel. The second terminal includes a one-side connection terminal and an other-side connection terminal for detecting whether the control panel is connected to the control device. The distance between the control device and the control panel when it is possible to detect whether the control panel is connected using the one-side connection terminal is different from the distance between the control device and the control panel when it is possible to detect whether the control panel is connected using the other-side connection terminal. The control device notifies a connection abnormality when a state in which it is possible to detect whether the control panel is connected using either the one-side connection terminal or the other-side connection terminal continues for a predetermined time.

JP 2018-122397 A

There are times when you want to eliminate a situation where the detection results of multiple detectors are different so that the control device does not determine that there is a connection abnormality.

The object of the present invention is to provide a detection device and machine tool that can switch from a state in which the detection results of multiple detection units differ to a state in which the detection results match.

The detection device according to the first aspect of the present invention is a detection device having a plurality of detection systems each including a detection switch whose conduction state is switched and a switch detection unit that detects the conduction state of the detection switch, and is characterized in that it is equipped with a switching unit for switching the states of the plurality of detection systems so that the conduction states detected by the switch detection units of the plurality of detection systems match, a determination unit for determining whether the conduction states detected by the switch detection units of the plurality of detection systems differ, and a change unit for switching the states of the plurality of detection systems by the switching unit and matching the conduction states detected by the switch detection units of the plurality of detection systems when the determination unit determines that the conduction states differ.

When the conduction states of the multiple detection switches detected by the multiple switch detection units differ, the detection device switches the states of the multiple detection systems using a switching unit so that the conduction states detected by the multiple switch detection units match. Therefore, even when the conduction states of the multiple detection switches differ, the detection device can match the conduction states detected by the multiple switch detection units.

In the first aspect, when the determination unit determines that the state in which the continuity states differ has continued for a predetermined time, the change unit may switch the states of the multiple detection systems using the switching unit, and match the continuity states detected by the switch detection units of the multiple detection systems. At that time, the detection device can prevent the continuity states detected by the multiple switch detection units from differing for a predetermined time.

In the first aspect, the switching unit may be an intervening switch that switches the conduction state between the detection switch of each of the multiple detection systems and the switch detection unit. The intervening switch can match the conduction states detected by the multiple switch detection units even if the conduction states of the multiple detection switches are different.

In a first aspect, the device further includes a position detection unit that detects position information corresponding to the position of an openable/closable door, and the detection switch switches the conductive state in response to the opening and closing of the door, and when the determination unit determines that the conductive states differ when the position information detected by the position detection unit is within a predetermined range, the change unit switches the states of the multiple detection systems using the switching unit, and matches the conductive states detected by the switch detection units of the multiple detection systems. At that time, the detection device can match the conductive states detected by the multiple switch detection units when the door is in a position that satisfies a predetermined condition.

In the first aspect, when the position information detected by the position detection unit changes from a state in the predetermined range to a state outside the predetermined range, the state of the multiple detection systems may be restored by the switching unit. At that time, the detection device can detect the conductive state of the multiple detection switches by the multiple switch detection units when the door is in a position that does not satisfy the predetermined condition.

The machine tool according to the second aspect of the present invention is characterized in that it includes the detection device according to the first aspect, the door capable of opening and closing an opening provided in the wall of the cover, and an arm that enters the inside of the cover through the open opening and conveys the workpiece held at its end toward the machine tool. According to the second aspect, the same effect as the first aspect is achieved.

FIG. 4 is a perspective view of the machine tool 1 with the door 6 closed, viewed from diagonally forward right. FIG. 4 is a perspective view of the machine tool 1 with the door 6 open, viewed from diagonally forward right. FIG. FIG. 2 is a perspective view of the arm device 12 as viewed diagonally from the front left. FIG. 2 is a block diagram showing the electrical configuration of the machine tool 1. FIG. 4 is a signal diagram when the door 6 moves from the maximum open position to the closed position. 4 is a signal diagram when the door 6 moves from the closed position to the maximum open position. 1 is a flow chart of the main process.

An embodiment of the present invention will be described. In the following description, the left/right, front/back, and up/down directions shown by arrows in the figures will be used. The left/right, front/back, and up/down directions of the machine tool 1 correspond to the X-axis, Y-axis, and Z-axis directions of the machine tool 1, respectively.

The structure of the machine tool 1 will be described with reference to Figures 1 and 2. The machine tool 1 rotates a spindle (not shown) to which a tool is attached, and cuts a workpiece fixed on a work table (not shown). The machine tool 1 includes a base 2 and a cover 5. The base 2 is provided at the bottom of the machine tool 1. The cover 5 is provided at the top of the base 2, and prevents chips and cutting fluid from scattering to the surrounding area. The cover 5 includes an operation panel 1A on the right side of the front. The cover 5 includes an opening 511, a wall 512, and a door 6 on the right side wall 51. The opening 511 is provided rearward of the center of the right side wall 51 and is formed in a substantially rectangular shape. The wall 512 is provided around the opening 511. The door 6 is provided slidably in the front-rear direction along the inner surface of the wall 512, and opens and closes the opening 511. The opening and closing mechanism of the door 6 includes, for example, guide rails (not shown) provided above and below the opening 511 in the right side wall 51, and multiple bearings provided at the top and bottom of the door 6. The guide rail extends in the Y-axis direction. The door 6 slides in the Y-axis direction as multiple bearings provided on the door 6 slide along the guide rail. Figure 1 shows the state in which the door 6 closes the opening 511. Figure 2 shows the state in which the door 6 opens the opening 511.

The transport device 10 is attached to the right side of the base 2. The transport device 10 communicates with the numerical control device 8 (see Figure 5) to transport the workpiece and open and close the door 6. The specific configuration of the transport device 10 will be described later. The cover 5 has a control box 1B on the back. The control box 1B stores the numerical control device 8. The numerical control device 8 controls the operation of the machine tool 1.

The configuration of the transport device 10 will be described with reference to Figures 1 and 2. The transport device 10 includes a moving part 11, an arm device 12, a moving mechanism 14, etc. The moving part 11 slides in the Y-axis direction by the moving mechanism 14. The arm device 12 is provided on the top of the moving part 11, is extendable in the X-axis direction and the Z-axis direction, and is capable of gripping the workpiece. Therefore, the arm device 12 can replace the workpiece held on the workbench inside the cover 5 with the door 6 open.

The movement mechanism 14 is provided on the right side of the base 2, and includes a frame 15, a movement motor 16 (see FIG. 5), a ball screw 17, a pair of travel shafts 18A and 18B, a bellows cover 19, etc. The frame 15 is formed in a generally rectangular shape when viewed from the right side, and is fixed to the right side of the base 2. The movement motor 16 is fixed so as to protrude rearward from the rear of the frame 15. The output shaft of the movement motor 16 protrudes forward within the frame 15. The ball screw 17 is disposed within the frame 15 so as to extend in the Y-axis direction, and is rotatable. The ball screw 17 is connected coaxially with the output shaft of the movement motor 16.

The traveling shafts 18A and 18B are arranged parallel to each other so as to sandwich the ball screw 17 from above and below inside the frame body 15 and extend in the Y-axis direction. The traveling shafts 18A and 18B support the moving part 11 so as to be guided in the Y-axis direction. In the following description, the traveling shafts 18A and 18B are collectively referred to as the traveling shaft 18. The moving part 11 is attached to the ball screw 17. The bellows cover 19 is provided on the frame body 15 and covers the opening of the frame body 15. The bellows cover 19 expands and contracts as the moving part 11 moves in the Y-axis direction. Therefore, the moving mechanism 14 can prevent chips and the like from entering the frame body 15. When the moving motor 16 is driven, the ball screw 17 rotates. As the ball screw 17 rotates, the moving part 11 moves in the Y-axis direction, and the arm device 12 moves in the Y-axis direction.

The arm device 12 comprises a main body 121 and an arm 122. The main body 121 is provided on the upper part of the moving part 11, and is formed in a generally rectangular parallelepiped shape that is long in the vertical direction. The main body 121 comprises a first joint 41 (see FIG. 4) on the upper front part. The first joint 41 supports a first arm 21 (described later) of the arm 122 so that it can rotate around an axis extending in the Y-axis direction. The main body 121 houses a first motor 81 (see FIG. 5) inside. The first motor 81 drives and rotates the first arm 21.

The main body 121 has a connecting mechanism 30 on the upper surface. As shown in FIG. 3A, the connecting mechanism 30 has a connecting rod 35 and sensors 36 and 37 (see FIG. 5). The connecting rod 35 is driven by an air cylinder (not shown) as a driving source so as to be able to move forward and backward in the left direction, which is the cover 5 side. As shown in FIG. 3B, the connecting rod 35 can be inserted into and engaged with a connecting hole 65 provided at the front end of the outer surface of the door 6. When the connecting rod 35 is inserted into and engaged with the connecting hole 65, the arm device 12 is connected to the door 6 via the connecting rod 35. Therefore, the door 6 can open and close the opening 511 in the right side wall 51 by moving in the Y-axis direction while connected to the arm device 12. The sensor 36 detects that the connecting rod 35 has moved to the standby position and outputs a signal. The standby position is the position of the connecting rod 35 when it is completely removed from the connecting hole 65. The sensor 37 detects that the connecting rod 35 has moved to the protruding position and outputs a signal. The protruding position is the position of the connecting rod 35 when it is engaged with the connecting hole 65.

As shown in FIG. 1, detection switch 61A is fixed to the upper rear inside wall 512. Although not shown, detection switch 62A is fixed to the lower rear inside wall 512. Detection switches 61A and 62A are limit switches. Detection switches 61A and 62A are spaced apart in the vertical direction. Detection switches 61A and 62A are collectively referred to as detection switch 6A. Detection switch 6A has contacts 601 and 602 (see FIG. 6) and a plunger 606.

The plunger 606 can come into contact with the rear end of the door 6, which slides along the inner surface of the wall portion 512. When the door 6 completely blocks the opening 511, the rear end of the door 6 comes into contact with the plungers 606 of the detection switches 61A and 62A. At that time, the contacts 601 and 602 of the detection switches 61A and 62A are conductive. When the door 6 does not block the opening 511, the door 6 moves forward away from the plungers 606 of the detection switches 61A and 62A. At that time, the contacts 601 and 602 of the detection switches 61A and 62A are not conductive. Hereinafter, when the contacts 601 and 602 are conductive, it is referred to as the detection switch 6A being ON, and when the contacts 601 and 602 are not conductive, it is referred to as the detection switch 6A being OFF.

The structure of the arm 122 will be described with reference to FIG. 4. The arm 122 includes a first arm 21 and a second arm 22 that can be folded. The first joint 41 of the main body 121 rotatably supports one end of the first arm 21. The first arm 21 includes a second joint 42 at the other end. The second joint 42 rotatably supports one end of the second arm 22 around an axis extending in the Y-axis direction. The second arm 22 includes a third joint 43 at the other end. The third joint 43 rotatably supports two gripping parts 23A and 23B (not shown in FIG. 1) around an axis extending in the Y-axis direction. The gripping parts 23A and 23B can grip the workpiece W.

The first arm 21 houses a second motor 82 (see FIG. 5) therein. The second motor 82 drives the second arm 22 via a gear (not shown) of the second joint 42. The second arm 22 houses a third motor 83 (see FIG. 5) therein. The third motor 83 rotates and drives the gripping parts 23A and 23B via a gear of the third joint 43. The gripping parts 23A and 23B each have an air cylinder 231 (see FIG. 5). The air cylinder 231 is a drive source for gripping the workpiece W. In the following description, when the two gripping parts 23A and 23B are collectively referred to as gripping parts 23.

An example of the operation of the conveying device 10 will be described. In the following description, in the X-axis direction, the direction to the right of the travel axis 18 and opposite the door 6 is the (+) direction, and the direction of the door 6 from the travel axis 18 is the (-) direction. In the Y-axis direction, the front is the (+) direction, and the rear is the (-) direction. As shown in FIG. 1, the position of the arm device 12 in the Y-axis direction when the door 6 is completely closed by the conveying device 10 is called the closed position. As shown in FIG. 2, the position of the arm device 12 in the Y-axis direction when the door 6 is completely opened by the conveying device 10 is called the maximum open position. The closed position and the maximum open position are indicated by the distance in the Y-axis direction from the origin to the arm device 12. The origin is indicated by the position of the arm device 12 when the door 6 is completely closed by the conveying device 10 (see FIG. 1). Therefore, the origin and the closed position coincide, and the distance between them is 0. The distance between the origin and the maximum open position is represented as Y(max).

As shown in FIG. 1, the conveying device 10 moves the connecting rod 35 toward the door 6 (leftward) with the arm device 12 in the closed position (FIG. 3(A) → FIG. 3(B)). The tip of the connecting rod 35 is inserted into the connecting hole 65, and the arm device 12 and the door 6 are connected. In this state, the conveying device 10 moves the arm device 12 in the Y-axis (+) direction at high speed. The arm device 12 opens the door 6 at high speed, widening the opening 511. The conveying device 10 stops after the arm device 12 has moved a distance Ymax in the Y-axis (+) direction. At that time, as shown in FIG. 2, the arm device 12 is in the maximum open position, and the opening 511 is fully open.

Next, the transport device 10 extends the arm 122 in the X-axis (-) direction. The arm 122 enters the cover 5 through the opening 511, and places the gripping portion 23 and the workpiece W inside the cover 5. The arm device 12 places the workpiece W on, for example, the top surface of the work table of the machine tool 1. After placing the workpiece W, the transport device 10 folds the arm 122 and contracts it in the X-axis (+) direction, and moves the gripping portion 23 out of the cover 5.

The transport device 10 moves at high speed in the Y-axis (-) direction with the arm device 12 connected to the door 6. When the detection switch 6A is turned ON, the transport device 10 stops the movement of the arm device 12. At that time, as shown in FIG. 1, the arm device 12 is in the closed position and the door 6 completely blocks the opening 511. The transport device 10 moves the connecting rod 35 back to the right. The connecting rod 35 comes out of the connecting hole 65 (FIG. 3(B) → FIG. 3(A)). The connection between the arm device 12 and the door 6 is released. This completes the series of operations of the transport device 10.

When only one of the detection switches 61A, 62A is ON and the other is OFF for a predetermined period of time or longer, the conveying device 10 determines that at least one of the detection switches 61A, 62A has failed. At that time, the machine tool 1 stops operating.

The electrical configuration of the machine tool 1 will be described with reference to FIG. 5. The conveying device 10 includes a control unit 70. The control unit 70 includes a CPU 71, a ROM 72, a RAM 73, a storage device 74, and an input/output unit 77. The CPU 71 controls the operation of the conveying device 10. The ROM 72 stores programs and the like for the CPU 71 to operate. The RAM 73 temporarily stores various information. The storage device 74 is a non-volatile storage device, and stores various parameters such as distance Y (max) and Y (inv) (described later). The input/output unit 77 inputs and outputs data to and from external devices. The input/output unit 77 is connected to the numerical control device 8, the encoders 16A, 81A, 82A, 83A, the moving motor 16, the first motor 81, the second motor 82, the third motor 83, the air cylinder 231, the sensors 36, 37, the detection switches 61A, 62A, and the intervening switches 61B, 62B described later.

The movement motor 16 is equipped with an encoder 16A. The encoder 16A detects the rotational position of the movement motor 16. The first motor 81 is equipped with an encoder 81A. The encoder 81A detects the rotational position of the first motor 81. The second motor 82 is equipped with an encoder 82A. The encoder 82A detects the rotational position of the second motor 82. The third motor 83 is equipped with an encoder 83A. The encoder 83A detects the rotational position of the third motor 83.

The detection mechanism 60 will be described with reference to FIG. 6. The detection mechanism 60 is a mechanism for detecting the closure of the door 6, and has detection systems 610 and 620. The detection system 610 detects the closure of the door 6 by a detection switch 61A. The detection system 620 detects the closure of the door 6 by a detection switch 62A.

The detection system 610 has a detection switch 61A, an intervening switch 61B, a switch detection unit 77A, and a switch changeover unit 77C. The switch detection unit 77A is provided in the input/output unit 77, and is capable of detecting the conductive state of the detection switch 61A. The switch detection unit 77A has a terminal block 771A that connects to the contact 601 of the detection switch 61A, and a terminal block 772A that connects to the contact 602 of the detection switch 61A via the intervening switch 61B.

The intermediate switch 61B is a photocoupler and is interposed between the contact 602 of the detection switch 61A and the terminal block 772A of the switch detection unit 77A. The emitter 603 of the intermediate switch 61B is connected to the contact 602 of the detection switch 61A. The collector 604 of the intermediate switch 61B is connected to the terminal block 772A of the switch detection unit 77A. The diode 605 of the intermediate switch 61B is connected to the switch changeover unit 77C.

The switch changeover unit 77C is provided in the input/output unit 77, and can switch the conductive state of the emitter 603 and collector 604 of the intervening switch 61B. When the emitter 603 and collector 604 are conductive, the contact 602 of the detection switch 61A and the terminal block 772A of the switch detection unit 77A are conductive. When the emitter 603 and collector 604 are not conductive, the contact 602 of the detection switch 61A and the terminal block 772A of the switch detection unit 77A are not conductive.

The detection switch 62A, the intervening switch 62B, the switch detection unit 77B, and the switch changeover unit 77D of the detection system 620 correspond to the detection switch 61A, the intervening switch 61B, the switch detection unit 77A, and the switch changeover unit 77C of the detection system 610, respectively. The terminal blocks 771B and 772B of the switch detection unit 77B correspond to the terminal blocks 771A and 772A of the switch detection unit 77A, respectively. The switch detection unit 77B and the switch changeover unit 77D are provided in the input/output unit 77.

Hereinafter, when the detection systems 610, 620 are not differentiated, they are collectively referred to as the detection system 600. When the intervening switches 61B, 62B are not differentiated, they are collectively referred to as the intervening switch 6B. When the emitter 603 and collector 604 of the intervening switch 6B are conductive, it is said that the intervening switch 6B is ON, and when the emitter 603 and collector 604 are not conductive, it is said that the intervening switch 6B is OFF. When the switch detection units 77A, 77B are not differentiated, they are collectively referred to as the switch detection unit 701. When the switch changeover units 77C, 77D are not differentiated, they are collectively referred to as the switch changeover unit 702.

The conveying device 10 performs a confirmation operation to confirm the relationship between the operation of the door 6 opening and closing the opening 511 and the rotational position of the moving motor 16 detected by the encoder 16A. In the confirmation operation, the arm device 12 connected to the door 6 is moved at a low speed between the closed position (see FIG. 1) and the maximum open position (see FIG. 2) by the drive of the moving motor 16. The conveying device 10 stores the rotational position detected by the encoder 16A at that time in the storage device 74.

A predetermined position in the Y-axis direction of the arm device 12, which is any position between the maximum open position and the closed position, is defined as the ineffective position (see Figures 7 and 8). The distance Y (inv) in the Y-axis direction between the origin (closed position) and the ineffective position is stored in advance in the memory device 74. When the arm device 12 connected to the door 6 is in any position between the ineffective position and the closed position, the contact state between the plunger 606 of the detection switch 6A and the door 6 changes. At that time, the conductive state of the detection switch 6A switches between ON and OFF.

Since the detection switches 61A and 62A are spaced apart in the vertical direction, the plungers 606 of the detection switches 61A and 62A come into contact with different positions on the door 6. There are also individual differences between the detection switches 61A and 62A. Therefore, when the arm device 12 moves from the inactive position to the closed position in the process of the door 6 closing the opening 511, the door 6 comes into contact with the plungers 606 of the detection switches 61A and 606 of the detection switches 62A at different times. Therefore, the detection switches 61A and 62A are switched from OFF to ON at different times. In the example shown in FIG. 7(A), with the intermediate switches 61B and 62B turned ON, the detection switch 62A is switched from OFF to ON first (time t11), and then the detection switch 61A is switched from OFF to ON (time t12).

The transport device 10 determines that the conductive state of the detection switch 62A detected by the switch detection unit 77B has switched from OFF to ON (time t13), and determines that the conductive state of the detection switch 62A detected by the switch detection unit 77A has switched from OFF to ON (time t14). During the period Y11 from time t13 to t14, the switch detection unit 77A detects that the detection switch 61A is OFF, and the switch detection unit 77B detects that the detection switch 62A is ON. The transport device 10 determines that the conductive states of the detection switches 61A and 62A detected by the switch detection units 77A and 77B are one ON and the other OFF.

During the confirmation operation, the arm device 12 moves at a low speed, so the period Y11 during which the conduction states of the detection switches 61A and 62A are different is longer than when the arm device 12 moves at a high speed. If this state continues for a predetermined time T11 or more before the period Y11 has elapsed, the transport device 10 determines that at least one of the detection switches 61A and 62A has failed and stops the operation of the machine tool 1. At that time, the transport device 10 cannot perform the confirmation operation while the door 6 is in the process of blocking the opening 511.

Similarly, when the arm device 12 moves from the closed position to the inactive position in the process of the door 6 opening the opening 511, the detection switches 61A and 62A switch from ON to OFF at different times. In the example shown in FIG. 8(A), with the intervening switches 61B and 62B turned ON, the detection switch 61A switches from ON to OFF first (time t21), and then the detection switch 62A switches from ON to OFF (time t22).

The conveying device 10 determines that the conductive state of the detection switch 61A detected by the switch detection unit 77A has switched from ON to OFF (time t23), and determines that the conductive state of the detection switch 62A detected by the switch detection unit 77B has switched from ON to OFF (time t24). During the period Y21 from time t23 to t24, the switch detection unit 77A detects that the detection switch 61A is OFF, and the switch detection unit 77B detects that the detection switch 62A is ON. The conveying device 10 determines that the conductive states of the detection switches 61A and 62A detected by the switch detection units 77A and 77B are one ON and the other OFF. If this state continues for a predetermined time T11 or more before the period Y21 has elapsed, the conveying device 10 determines that at least one of the detection switches 61A, 62A has failed and stops the operation of the machine tool 1. At that time, the conveying device 10 cannot perform the confirmation operation while the door 6 is in the process of opening the opening 511.

In response to this, the transport device 10 switches the state of the detection system 600 using the intervening switch 6B so that the conduction states detected by the switch detection units 77A and 77B match. This allows the transport device 10 to perform the confirmation operation even when the arm device 12 is moving at a low speed. The details are as follows.

As shown in FIG. 7B, when the conveying device 10 performs a check operation to confirm that the door 6 is blocking the opening 511, it determines that the conduction state of the detection switch 62A detected by the switch detection unit 77B has switched from OFF to ON (time t31). Note that since the conduction state of the detection switch 61A detected by the switch detection unit 77A is OFF, the conduction states of the detection switches 61A and 62A detected by the switch detection units 77A and 77B are different at this point.

After a predetermined time T12 has elapsed from time t31, the conveying device 10 controls the switch changeover units 77C and 77D to switch the intermediate switches 61B and 62B from ON to OFF (times t32 and t33). The predetermined time T12 is shorter than the predetermined time T11 (T11>T12). At that time, the conduction state of the detection switch 62A detected by the switch detection unit 77B switches from ON to OFF (time t34). The conduction states of the detection switches 61A and 62A detected by the switch detection units 77A and 77B are both OFF and match. The state in which the conduction states of the detection switches 61A and 62A detected by the switch detection units 77A and 77B are different does not continue for more than the predetermined time T11. Therefore, unlike FIG. 7(A), the conveying device 10 does not determine that at least one of the detection switches 61A and 62A has failed, and does not stop the operation of the machine tool 1. Therefore, the conveying device 10 can perform a confirmation operation while the door 6 is in the process of closing the opening 511.

Then, the conveying device 10 acquires the current position of the arm device 12 in the Y-axis direction based on the rotational position of the movement motor 16 detected by the encoder 16A. The conveying device 10 determines whether the arm device 12 has moved to the closed position based on the acquired current position. When the arm device 12 has moved to the closed position, the conveying device 10 controls the switch changeover units 77C and 77D to switch the intermediate switches 61B and 62B from OFF to ON (times t35 and t36). At time t12 before the arm device 12 moves to the closed position, the detection switch 61A switches from OFF to ON. The conductive states of the detection switches 61A and 62A are both ON. Therefore, after the intervening switches 61B and 62B are turned ON at times t35 and t36, the conduction states of the detection switches 61A and 62A detected by the switch detection units 77A and 77B are both ON and match.

As shown in FIG. 8(B), when the conveying device 10 performs a confirmation operation to confirm that the door 6 opens the opening 511, it determines that the conduction state of the detection switch 61A detected by the switch detection unit 77A has switched from ON to OFF (time t41). Note that the conduction state of the detection switch 62A detected by the switch detection unit 77B is ON, so the conduction states of the detection switches 61A and 62A detected by the switch detection units 77A and 77B are different at this point.

After a predetermined time T12 has elapsed from time t41, the conveying device 10 controls the switch changeover units 77C and 77D to switch the intermediate switches 61B and 62B from ON to OFF (times t42 and t43). At that time, the conveying device 10 switches the conduction state of the detection switch 62A detected by the switch detection unit 77B from ON to OFF (time t44). The conduction states of the detection switches 61A and 62A detected by the switch detection units 77A and 77B are both OFF and match. The state in which the conduction states of the detection switches 61A and 62A detected by the switch detection units 77A and 77B are different does not continue for more than the predetermined time T11. Therefore, unlike FIG. 8(A), the conveying device 10 does not determine that at least one of the detection switches 61A and 62A has failed, and does not stop the operation of the machine tool 1. Therefore, the conveying device 10 can perform a checking operation while the door 6 is in the process of opening the opening 511.

Then, the conveying device 10 acquires the current position of the arm device 12 in the Y-axis direction based on the rotational position of the movement motor 16 detected by the encoder 16A. The conveying device 10 determines whether the arm device 12 has moved to the invalid position based on the acquired current position. When the arm device 12 has moved to the invalid position, the conveying device 10 controls the switch changeover units 77C and 77D to switch the intermediate switches 61B and 62B from OFF to ON (times t45 and t46). At time t22 before the arm device 12 moves to the invalid position, the detection switch 62A switches from ON to OFF. The conductive states of the detection switches 61A and 62A are both OFF. Therefore, after the intervening switches 61B and 62B are turned ON at times t45 and t46, the conduction states of the detection switches 61A and 62A detected by the switch detection units 77A and 77B are both OFF and match.

The main process will be described with reference to FIG. 9. The main process starts when the transport device 10 executes a confirmation operation by having the CPU 71 read and execute a program stored in the ROM 72.

The CPU 71 controls the switch changeover units 77C and 77D to turn on the intermediate switches 61B and 62B (S11). The CPU 71 determines whether the arm device 12 and the door 6 are connected based on the signals output by the sensors 36 and 37 (S13). If the CPU 71 determines that the connecting rod 35 is in the standby position based on the signal detected by the sensor 36, it determines that the arm device 12 and the door 6 are not connected (S13: NO). At that time, the CPU 71 returns the process to S11. If the CPU 71 determines that the connecting rod 35 is in the extended position based on the signal detected by the sensor 37, it determines that the arm device 12 and the door 6 are connected (S13: YES). At that time, the CPU 71 advances the process to S15.

The CPU 71 acquires the current position of the arm device 12 in the Y-axis direction based on the rotational position of the movement motor 16 detected by the encoder 16A. The CPU 71 determines whether the acquired current position is on the (+) side of the closed position in the Y-axis direction and on the (-) side of the invalid position in the Y-axis direction based on the distance Y(inv) stored in the storage device 74 (S15). If the CPU 71 determines that the acquired current position is on the (+) side of the closed position in the Y-axis direction and on the (-) side of the invalid position in the Y-axis direction (S15: YES), the current position is between the closed position and the invalid position, and the process proceeds to S17.

The CPU 71 acquires the conductive state of the detection switch 61A detected by the switch detection unit 77A and the conductive state of the detection switch 62A detected by the switch detection unit 77B. The CPU 71 determines whether the acquired conductive states of the detection switches 61A and 62A are different (S17). If the CPU 71 determines that the acquired conductive states of the detection switches 61A and 62A are the same (S17: NO), the process returns to S11. If the CPU 71 determines that the acquired conductive states of the detection switches 61A and 62A are different (S17: YES), the process proceeds to S19.

The CPU 71 determines whether the state in which the respective conduction states of the detection switches 61A and 62A differ has continued for a predetermined time T12 or more (S19). If the CPU 71 determines that the state in which the respective conduction states of the detection switches 61A and 62A differ has not continued for the predetermined time T12 or more (S19: NO), the process returns to S17. If the CPU 71 determines that the state in which the respective conduction states of the detection switches 61A and 62A differ has continued for the predetermined time T12 or more (S19: YES), the process proceeds to S21.

The CPU 71 controls the switch changeover units 77C and 77D to turn off the intermediate switches 61B and 62B (S21) and switch the states of the detection systems 610 and 620. At that time, the conductive state of the detection switch 61A detected by the switch detection unit 77A and the conductive state of the detection switch 62A detected by the switch detection unit 77B are both OFF and match, regardless of the actual conductive states of the detection switches 61A and 62A. The CPU 71 advances the process to S23.

The CPU 71 acquires the current position of the arm device 12 in the Y-axis direction based on the rotational position of the moving motor 16 detected by the encoder 16A. The CPU 71 determines whether the acquired current position is on the negative side of the closed position in the Y-axis direction or on the positive side of the invalid position in the Y-axis direction based on the distance Y(inv) stored in the storage device 74 (S23). If the CPU 71 determines that the acquired current position is on the positive side of the closed position in the Y-axis direction and on the negative side of the invalid position in the Y-axis direction (S23: NO), the process returns to S21. If the CPU 71 determines that the acquired current position is on the negative side of the closed position in the Y-axis direction or on the positive side of the invalid position in the Y-axis direction (S23: YES), the process returns to S11. The CPU 71 controls the switch changeover units 77C and 77D to return the intermediate switches 61B and 62B that were turned OFF in S21 to their original ON states (S11).

If the CPU 71 determines in the process of S15 that the acquired current position is on the (-) side of the closed position in the Y-axis direction or on the (+) side of the invalid position in the Y-axis direction (S15: NO), the process proceeds to S25. If the CPU 71 determines that the acquired current position is on the (+) side of the invalid position in the Y-axis direction (S25: NO), the process returns to S11. If the CPU 71 determines that the acquired current position is on the (-) side of the closed position in the Y-axis direction (S25: YES), the process proceeds to S27.

The CPU 71 determines whether the current position is on the negative side of the closed position in the Y-axis direction for a predetermined time T3 or more (S27). If the CPU 71 determines that the current position is not on the negative side of the closed position in the Y-axis direction for a predetermined time T3 or more (S27: NO), the process returns to S11. If the CPU 71 determines that the current position is on the negative side of the closed position in the Y-axis direction for a predetermined time T3 or more (S27: YES), the CPU 71 outputs a notification signal to the numerical control device 8 to notify the user that the detection switch 6A may have failed. The numerical control device 8 notifies the user by displaying an error code indicating that the detection switch 6A may have failed on a display unit included in the operation panel 1A (S29). The CPU 71 ends the main process.

When the conductive states of the detection switches 61A, 62A detected by the switch detectors 77A, 77B differ (S17: YES), the conveying device 10 switches the states of the detection systems 610, 620 using the intervening switches 61B, 62B so that the conductive states detected by the switch detectors 77A, 77B match (S21). Therefore, even if the conductive states of the detection switches 61A, 62A differ, the conveying device 10 can match the conductive states detected by the switch detectors 77A, 77B. Therefore, the conveying device 10 can avoid determining that at least one of the detection switches 61A, 62A has failed during the confirmation operation, and can reliably perform the confirmation operation.

When the conveying device 10 determines that the difference in the conduction states of the detection switches 61A and 62A detected by the switch detection units 77A and 77B continues for a predetermined time T12 (S17: YES, S19: YES), the conveying device 10 switches the state of the detection systems 610 and 620 using the intermediate switches 61B and 62B (S21). In this case, the conveying device 10 can prevent the conduction states of the detection switches 61A and 62A detected by the switch detection units 77A and 77B from continuing to differ for more than the predetermined time T12. In addition, when the conduction states of the detection switches 61A and 62A detected by the switch detection units 77A and 77B continue to differ for more than the predetermined time T11 (T11>T12), the conveying device 10 determines that at least one of the detection switches 61A and 62A has failed. Therefore, the above operation allows the transport device 10 to avoid determining that at least one of the detection switches 61A and 62A has failed, so the confirmation operation can be performed reliably.

The conveying device 10 switches the conduction state between the detection switch 61A of the detection system 610 and the switch detection unit 77A by the intervening switch 61B, and switches the conduction state between the detection switch 62A of the detection system 620 and the switch detection unit 77B by the intervening switch 62B. At that time, the intervening switches 61B and 62B can match the conduction states detected by the switch detection units 77A and 77B even if the actual conduction states of the detection switches 61A and 62A differ.

The conveying device 10 acquires the current position of the arm device 12 in the Y-axis direction based on the rotational position of the moving motor 16 detected by the encoder 16A. When the current position of the arm device 12 is on the (+) side of the Y-axis direction from the closed position and on the (-) side of the Y-axis direction from the invalid position (i.e., any position between the closed position and the invalid position) (S15: YES), if the conduction states of the detection switches 61A and 62A detected by the switch detection units 77A and 77B are different (S17: YES), the conveying device 10 switches the state of the detection systems 610 and 620 by the intermediate switches 61B and 62B (S21). Note that when the arm device 12 connected to the door 6 is in any position between the closed position and the invalid position, the contact state of the plunger 606 and the door 6 changes, and the conduction state of the detection switches 61A and 62A is switched. Therefore, the conveying device 10 can match the electrical continuity states detected by the switch detection units 77A and 77B at the timing when the contact state between the plungers 606 of the detection switches 61A and 62A and the door 6 changes and the electrical continuity state is switched.

When the conveying device 10 determines that the current position is on the negative side of the closed position in the Y-axis direction, or on the positive side of the invalid position in the Y-axis direction (i.e., any position except between the closed position and the invalid position) (S23: YES), it turns on the intermediate switches 61B, 62B (S11) and returns the detection systems 610, 620 to their original states. Note that when the arm device 12 connected to the door 6 is in any position except between the closed position and the invalid position, the contact state between the plungers 606 of the detection switches 61A, 62A and the door 6 does not change, and the conductive state does not switch. At that time, the conveying device 10 can maintain a state in which the conductive state of the detection switches 61A, 62A can be detected by the switch detection units 77A, 77B.

The present invention is not limited to the above embodiment, and various modifications are possible. The conveying device 10 is not limited to being installed in the machine tool 1, but may be installed in other equipment that opens and closes an opening with a door. The conveying device 10 may be installed in other equipment that is capable of detecting the position of a moving object other than a door.

The conveying device 10 moves the arm device 12 connected to the door 6 to move the door 6 and open and close the opening 511. The conveying device 10 may also directly move the door 6 by driving the movement motor 16 to open and close the opening 511. In other words, the conveying device 10 may move the arm device 12 and the door 6 independently.

The positions at which the detection switches 61A and 62A are provided are not limited to those in the above embodiment. The number of detection systems 600 including the detection switch 6A, the intervening switch 6B, and the switch detection unit 701 is not limited to two, and may be three or more. A detection system that detects the door 6 when the arm device 12 is in the maximum open position may be further provided. The detection switch 6A is not limited to a limit switch, and may be other switches including contact and non-contact switches.

When the conveying device 10 determines that the respective conductive states of the detection switches 61A and 62A are different (S17: YES), it may turn off the intermediate switches 61B and 62B (S21) regardless of whether the state has continued for a predetermined time T12 or more, and switch the state of the detection systems 610 and 620.

The intermediate switch 6B does not have to be provided for each of the detection systems 610 and 620. That is, one intermediate switch 6B common to the detection systems 610 and 620 may be provided. The intermediate switch 6B is not limited to a photocoupler, and may be another switch (transistor switch, relay, etc.) capable of switching the conduction state between the contact and the terminal block. The conveying device 10 may switch the state of the detection systems 610 and 620 so that the conduction states detected by the switch detection units 77A and 77B match by a method other than switching the switch. For example, the conveying device 10 may forcefully pull up or pull down the terminal block 772A of the switch detection unit 77A and the terminal block 772B of the switch detection unit 77B, respectively, to match the conduction states detected by the switch detection units 77A and 77B.

The conveying device 10 may determine whether the conduction states of the detection switches 61A and 62A differ across the entire range from the closed position to the maximum open position.

The conveying device 10 may turn off only one of the intervening switches 61B and 62B in the process of S21. For example, the conveying device 10 may control the switch changeover unit 77D to change only the intervening switch 62B from ON to OFF (time t33) after a predetermined time T12 has elapsed since the conveying device 10 determined that the conductive state of the detection switch 62A detected by the switch detection unit 77B has changed from OFF to ON at time t11 in FIG. 7B. At that time, even if the intervening switch 61B is not turned off, the conductive states of the detection switches 61A and 62A detected by the switch detection units 77A and 77B will both be OFF and will match. Thereafter, for example, the conveying device 10 may control the switch changeover unit 77C to change the intermediate switch 61B from ON to OFF after a predetermined time T12 has elapsed since it was determined that the conductive state of the detection switch 61A detected by the switch detection unit 77A has changed from OFF to ON at time t12 in FIG. 7B. At that time, the intermediate switches 61B and 62B are both OFF, so that the conductive states of the detection switches 61A and 62A detected by the switch detection units 77A and 77B are both OFF and match. In other words, the conveying device 10 only needs to change the state of the intermediate switch 6B so that the conductive states detected by the switch detection units 701 of the detection systems 610 and 620 match, and the conductive states of the intermediate switches 61B and 62B do not necessarily have to match.

The conveying device 10 is an example of a "detection device" of the present invention. The machine tool 1 is an example of a "conveying device". The intervening switch 6B is an example of a "switching unit" of the present invention. The CPU 71 that performs the processes of S17 and S19 is an example of a "determination unit" of the present invention. The CPU 71 that performs the process of S21 is an example of a "changing unit" of the present invention. The encoder 16A is an example of a "position detection unit" of the present invention.

1: Machine tool 5: Cover 6: Door 6A, 61A, 62A: Detection switch 6B, 61B, 62B: Intervening switch 10: Conveyor device 16A: Encoder 60A: Detection system 60B: Detection system 71: CPU
77A, 77B, 701: switch detection section 77C, 77D, 702: switch changeover section 511: opening 512: wall section 600, 610, 620: detection system

Claims (6)

A detection device for detecting a position of a moving object , the detection device including a plurality of detection systems each including a detection switch whose conductive state is switched and a switch detector that detects the conductive state of the detection switch,
a switching unit for switching states of the plurality of detection systems so that the conduction states detected by the respective switch detection units of the plurality of detection systems coincide with each other;
a determination unit that determines whether the conduction states detected by the switch detection units of the plurality of detection systems are different;
a change unit that, when the judgment unit determines that the conduction states are different, switches the states of the multiple detection systems using the switching unit , and matches the conduction states detected by the switch detection units of each of the multiple detection systems. The change unit is
The detection device according to claim 1, characterized in that when the determination unit determines that the state in which the conductivity states differ has continued for a predetermined time period that is shorter than the time for which it is determined that at least one of the detection switches has failed, the states of the multiple detection systems are switched by the switching unit, and the conductivity states detected by the switch detection units of the multiple detection systems are made to be consistent. The switching unit is
3. The detection device according to claim 1, further comprising an intervening switch that switches a conductive state between the detection switch of each of the plurality of detection systems and the switch detection unit. The device further includes a position detection unit that detects position information corresponding to the position of the openable/closable door,
The detection switch switches the conductive state depending on whether the door is opened or closed,
The change unit is
A detection device as described in any one of claims 1 to 3, characterized in that when the position information detected by the position detection unit is within a predetermined range and the judgment unit judges that the conduction states are different, the states of the multiple detection systems are switched by the switching unit, and the conduction states detected by the switch detection units of each of the multiple detection systems are made to be consistent. The switching unit is
by switching the detection switch and the switch detector from a conductive state to a non-conductive state, the states of the plurality of detection systems are switched so that the conductive states detected by the respective switch detectors of the plurality of detection systems coincide with each other;
The detection device according to claim 4, characterized in that when the position information detected by the position detection unit changes from a state in which it is within the specified range to a state in which it is outside the specified range , the switching unit switches a state in which the detection switches of each of the multiple detection systems and the switch detection unit are not conductive to a conductive state . A detection device according to claim 4 or 5,
the door capable of opening and closing an opening provided in a wall portion of the cover;
and an arm portion that enters the inside of the cover through the open opening and transports a workpiece held at an end thereof.

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