JP5667951B2 - Pallet change motion detection device - Google Patents

Description

  The present invention detects, for example, whether or not a pallet exchanging operation has been performed normally in a pallet exchanging device for a horizontal machining center, more specifically, a pallet exchanging device for exchanging pallets between a processing position and a setup position. The present invention relates to a pallet exchange operation detection device.

  The pallet changer can be positioned at the upper limit of the lift stroke, the pallet replacement arm on which the pallet is placed, the lift mechanism that lifts and lowers the arm at a fixed stroke with the arm positioned at the setup position or the processing position. The arm is positioned at the setup position by sequence control of the turning mechanism that turns the arm at a fixed stroke so that it can be alternately advanced and retracted with respect to the setup position and the machining position, and the turning mechanism and the lifting mechanism. In this state, the arm is moved from the lower limit of the lifting stroke to the upper limit, the revolving stroke for turning the arm from the setup position to the machining position, and the arm is moved to the upper limit of the lifting stroke with the arm positioned at the machining position. And a control device that sequentially performs a descending stroke that descends to the lower limit. To have.

  In the pallet exchanging apparatus, whether the pallet exchanging operation is normal or abnormal is determined by detecting a rotation angle of a motor for turning the arm. When trouble occurs in the turning mechanism, for example, when the timing belt for transmitting the power of the motor to the arm is cut, the up / down stroke is performed even if the turning stroke is not performed. Then, there is a possibility that a workpiece different from the workpiece that should originally be loaded into the machining position is loaded, and a program operation different from the program originally performed on the loaded workpiece may be started. In this case, there is a risk of machine damage due to the machine colliding with the workpiece.

  Other pallet changing devices include a pallet changing arm on which a pallet is placed, a lifting mechanism that lifts and lowers the arm at a fixed stroke with the arm positioned at the set-up position or the machining position, and a lifting stroke upper limit. A swing mechanism that turns the arm positioned at a fixed stroke so that the arm can be alternately advanced and retracted with respect to the setup position and the machining position, and an arm positioned at the lower limit of the lifting stroke at the setup position are detected. A first sensor; a second sensor for detecting an arm positioned at the upper limit of the lifting stroke at the setup position; a third sensor for detecting an arm positioned at the upper limit of the lifting stroke at the processing position; Based on the signals of the fourth sensor for detecting the arm positioned at the lower limit of the stroke and the first to fourth sensors, Controls the turning mechanism and the lifting mechanism. With the arm positioned at the setup position, the arm is raised from the lower limit of the lifting stroke to the upper limit, and the arm is moved from the setup position to the machining position. And a control device that sequentially performs a lowering stroke for lowering the arm from the upper and lower strokes to the lower limit with the swivel stroke and the arm positioned at the machining position. Instead of controlling, the signals of the first to fourth sensors are known to be used as triggers for starting and ending the stroke (see, for example, Patent Document 1).

  In this other pallet exchanging apparatus, since four first to fourth sensors are required, there is a problem in that the structure and control for the apparatus are complicated, and the equipment cost is high.

Japanese Utility Model Publication No. 61-37479

  An object of the present invention is to detect whether or not a pallet exchanging operation has been normally performed, thereby avoiding a malfunction of the machine. This can be achieved by using a minimum number of sensors. An object of the present invention is to provide an exchange operation detection device.

  A pallet replacement operation detecting device according to the present invention includes a pallet replacement arm on which a pallet is placed, a lifting mechanism that lifts and lowers the arm at a fixed stroke in a state where the arm is positioned at a setup position or a machining position, and a lifting stroke upper limit. The swivel mechanism that swivels at a fixed stroke so that the arm positioned at the set position and the machining position can be alternately advanced and retracted, and the swivel mechanism and the lifting mechanism are controlled to bring the arm to the set position. In the state where the arm is positioned, the arm is moved up from the lower limit of the lifting stroke to the upper limit, the swing stroke that turns the arm from the setup position to the machining position, and the arm is positioned at the machining position. A pallet having a control device for sequentially performing a descending stroke that descends from the upper and lower strokes to the lower limit In the robot exchanging device, the first sensor for detecting the arm positioned at the lower limit of the lifting stroke at the setup position, the second sensor for detecting the arm during the turning stroke, and the lower limit of the lifting stroke at the machining position. It comprises a third sensor that detects the arm, and a determination means that determines whether the pallet replacement operation is normal or abnormal based on detection signals from the first sensor, the second sensor, and the third sensor.

  In the pallet replacement operation detection device according to the present invention, the position of the pallet is from the lower limit of the lifting stroke at the setup position to the lower limit of the lifting stroke at the machining position, including during the arm turning from the setup position to the machining position at the upper limit of the lifting stroke. And can be detected by three sensors. Therefore, it is possible to avoid malfunction of the machine by detecting whether or not the pallet exchanging operation is normally performed. Moreover, since the number of necessary sensors is three, the equipment cost is low.

  Further, the arm is fixed to a vertical swivel shaft extending between the setup position and the machining position, and a horizontal disc-shaped detection plate is concentrically fixed to the swivel shaft, and the outer peripheral surface of the detection plate If the second sensor is fixedly arranged so that the second sensor can detect the sensor, the sensor detects the outer peripheral surface of the detection plate that is rotated as the arm turns. The motion can be detected by one sensor.

  The detection plate is provided with a first dog and a second dog spaced in the circumferential direction of the detection plate at an interval corresponding to the turning stroke. The first dog is the first sensor, and the second dog is the third sensor. If the first sensor and the third sensor are fixedly arranged so that they can be detected, the arm's turning can be detected separately by the two sensors before and after the turning, so that the arm's turning stroke is ensured. Can be detected.

  Further, instead of providing two dogs on the detection plate, one dog is provided on the detection plate, and the first sensor and the third sensor can detect the dog by the first sensor and the third sensor, respectively. If the three sensors are arranged in a fixed manner, the detection plate and the dog can be configured simply.

  According to the present invention, it is possible to detect whether or not the pallet exchanging operation has been normally performed and to avoid malfunction of the machine, and this can be achieved by using a minimum number of sensors. An exchange motion detection device is provided.

It is a perspective view of the pallet exchanging device provided with the pallet exchanging operation detecting device according to the present invention. FIG. 2 is a perspective view of the pallet replacement operation detection device showing a part of FIG. 1 in an enlarged manner. It is explanatory drawing which shows the vertical direction arrangement | positioning aspects, such as a sensor of the pallet replacement | exchange operation | movement detection apparatus. It is explanatory drawing which shows the horizontal direction arrangement | positioning aspects, such as a sensor of the pallet replacement | exchange operation | movement detection apparatus.

  Referring to FIG. 1, the internal space of the machine tool is partitioned into a setup chamber 12 and a processing chamber 13 by a vertical plate-shaped partition wall 11. A setup position S1 is set in the setup chamber 12, and a processing position S2 is set in the processing chamber 13. The setup position S1 and the processing position S2 are respectively set on straight lines orthogonal to the partition wall 11 when viewed from the plane.

  A vertical cylindrical turning shaft 21 extends between the setup position S1 and the machining position S2. The pivot shaft 21 is covered with a rectangular tube cover 22. The upper end of the cover 22 is covered with a horizontal annular plate 23 that passes through the upper end of the pivot shaft 21. A circular rod-shaped guide post 24 held at a fixed position is passed through the turning shaft 21. The upper end portion of the guide post 24 protrudes upward from the upper end surface of the turning shaft 21.

  The turning shaft 21 is turned reversibly by 180 degrees by a turning mechanism (not shown), and is moved up and down by a fixed stroke by an elevating mechanism (not shown). The turning mechanism includes a motor with an angle detector and a timing belt that transmits the power of the motor to the turning shaft 21. The lifting mechanism includes a hydraulic cylinder in which a piston rod is connected to the turning shaft 21.

  A first arm 31 and a second arm 32 are fixed to the pivot shaft 21 in opposite directions. In FIG. 1, the first arm 31 is positioned at the setup position S1, and the second arm 32 is positioned at the machining position S2. A first pallet P1 is placed on the first arm 31, and a second pallet P2 is placed on the second arm 32, respectively.

  FIG. 2 shows the upper end portion of the pivot shaft 21 shown in FIG. 1 and its peripheral portion in detail. A horizontal disc-shaped detection plate 41 is fixed to the upper end surface of the pivot shaft 21 concentrically with the upper end surface. A horizontal disc-like support plate 42 is fixed to the upper end portion of the guide post 24 with a space above the detection plate 41. A hanging plate-like first dog 51 and second dog 52 are fixed to the outer peripheral edge of the lower surface of the detection plate 41 at intervals in the circumferential direction of the detection plate 41. A first sensor 71 and a second sensor 72 are suspended from the support plate 42 via a first bracket 61 and a second bracket 62, respectively. Further, a third sensor 73 is suspended from the support plate 42 in parallel with the first sensor 71.

In FIG. 3 (a), the turning shaft 21 is positioned at the lower limit of the lifting stroke. In this state, the first dog 51 and the second dog 52, and the first sensor 71 and the third sensor 73 are positioned at the same level. The second sensor 72 is positioned above the detection plate 41 at an upper level. When the pivot shaft 21 is positioned at the upper limit of the lifting stroke, as shown in FIG.
The first dog 51 and the second dog 52 are positioned higher than the first sensor 71 and the third sensor 73, and the outer peripheral surfaces of the second sensor 72 and the detection plate 41 are at the same level.

  The arrangement of the first and second dogs 51, 52 and the first to third sensors 71, 72, 73 as viewed from above is shown in FIGS. A straight line passing through the axis of the turning shaft 21 and connecting the setup position S1 and the machining position S2 is defined as a first reference line L1. A straight line that passes through the axis of the turning shaft 21 and is orthogonal to the first reference line L1 is defined as a second reference line L2. FIG. 4 (a) corresponds to the arrangement shown in FIGS. The first dog 51 and the second dog 52 are arranged symmetrically with respect to the first reference line L1. The first sensor 71 and the third sensor 73 are arranged symmetrically with respect to the second reference line L2. The second sensor 72 is disposed on the second reference line L2. In FIG. 4A, the first dog 51 is made to be opposed to the first sensor 71. When the turning shaft 21 is turned 180 degrees counterclockwise from the state shown in FIG. 4A, it is as shown in FIG. 4B. A second dog 52 is made to be opposed to the third sensor 73. Through FIG. 4A to FIG. 4B, the outer peripheral surface of the detection plate 41 is opposed to the second sensor 72.

  Next, the pallet replacement operation will be described. The pallet exchanging operation is sequentially performed in the following first to third steps by sequentially controlling the turning mechanism and the lifting mechanism by an NC device (not shown). In the first step, with the first arm 31 at the setup position S1 and the second arm 32 at the machining position S2, the first arm 31 and the second arm 32 are moved from the lower and upper strokes to the upper limit. Move. In the second step, the first arm 31 is turned from the setup position S1 to the machining position S2, and the second arm 32 is turned from the machining position S2 to the setup position S1. In the third step, with the first arm 31 at the machining position S2 and the second arm 32 at the setup position S1, the first arm 31 and the second arm 32 are moved from the upper and lower strokes to the lower limit. Let Through the above steps, the first pallet P1 is replaced with the second pallet P2 at the setup position S1, and the second pallet P2 is replaced with the first pallet P1 at the processing position S2. The first to third steps are performed in the reverse sequence, and the state shown in FIGS. 1 and 2 is restored by performing the fourth to sixth steps not described in detail.

  When the first arm 31 is positioned at the setup position S1, the second arm 32 is positioned at the machining position S2, and the pivot shaft 21 is positioned at the lower limit of the lifting stroke, the first dog 51 is moved to the first sensor. 71 detects. Starting from this state, if the swivel shaft 21 is raised from the lower limit to the upper limit of the lifting stroke, the first sensor 51 cannot detect the first dog 51. Instead, the outer surface of the detection plate 41 is moved to the second sensor. 72 detects. When the pivot shaft 21 is turned 180 degrees counterclockwise with the pivot shaft 21 positioned at the upper limit of the lifting stroke, the first arm 31 is moved from the setup position S1 to the machining position S2, and the second arm 32 is machined. Each is turned from position S2 to setup position S1. During the turning of the turning shaft 21, the second sensor 72 continues to detect the outer peripheral surface of the detection plate 41. When the turning of the turning shaft 21 is completed, the turning shaft 21 is lowered from the upper limit to the lower limit of the lifting stroke. Then, the second sensor 72 cannot detect the outer peripheral surface of the detection plate 41, and this time, the third sensor 73 detects the second dog 52.

  Detection signals of the first sensor 71, the second sensor 72, and the third sensor 73 are input to the NC device. In the NC unit, normal / abnormal pallet replacement operation is judged as follows. When the first sensor 71, the second sensor 72, and the third sensor 73 detect ON sequentially, the pallet replacement operation is normal. When any of the first sensor 71, the second sensor 72, and the third sensor 73 detects OFF, it is determined that the pallet replacement operation is abnormal, an alarm is displayed, and the machine is stopped.

In the above, by arranging the first sensor 71 and the third sensor 73 on the opposite side of 180 ° with respect to the turning shaft 21, both the sensors 71 and 73 can detect the first dog 51, and one dog is used. It becomes possible to comprise. Note that the positions of the sensors 71 and 73 are not limited to the opposite side of 180 °, and it is possible to appropriately change the position within a range that does not depart from the spirit of the present invention, such as widening the dog. .

  The pallet exchanging operation detecting device according to the present invention achieves detecting whether or not the pallet exchanging operation is normally performed in the pallet exchanging device that performs the pallet exchanging operation between the processing position and the setup position. Is suitable.

31, 32 arms
P1, P2 palette
S1 Setup position
S2 machining position

Claims (4)

A pallet replacement arm on which a pallet is placed;
An elevating mechanism that moves the arm up and down with a fixed stroke in a state where the arm is positioned at the setup position or the machining position;
A turning mechanism for turning the arm positioned at the upper and lower strokes at a fixed stroke so as to be alternately advanced and retracted with respect to the setup position and the machining position;
With the arm and the lifting mechanism controlled to position the arm at the setup position, the arm is raised from the lower limit of the lifting stroke to the upper limit, and the arm is swung from the setup position to the machining position. In a pallet exchanging apparatus comprising a control device that sequentially performs a lowering stroke for lowering the arm from the upper and lower strokes to the lower limit in a state where the stroke and the arm are located at the machining position,
A first sensor for detecting an arm positioned at the lower limit of the lifting stroke at the set-up position;
A second sensor for detecting an arm during a turning stroke;
A third sensor for detecting an arm positioned at the lower limit of the lifting stroke at the machining position;
Determination means for determining normality / abnormality of the pallet replacement operation based on detection signals of the first sensor, the second sensor, and the third sensor;
A pallet replacement operation detection device.   The arm is fixed to a vertical swivel shaft extending between the setup position and the machining position, and a horizontal disc-shaped detection plate is fixed to the swivel shaft concentrically. The pallet replacement operation detection apparatus according to claim 1, wherein the second sensor is fixedly arranged so that the two sensors can detect it.   The detection plate is provided with a first dog and a second dog spaced in the circumferential direction of the detection plate at an interval corresponding to the turning stroke. The first dog is detected by the first sensor, and the second dog is detected by the third sensor. The pallet replacement operation detection device according to claim 2, wherein the first sensor and the third sensor are arranged in a fixed manner so as to be able to do so.   3. The pallet according to claim 2, wherein one dog is provided on the detection plate, and the first sensor and the third sensor are fixedly arranged so that the first sensor and the third sensor can detect the dog, respectively. Exchange operation detection device.

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