JP5236262B2 - Pallet conveyor for game board production, game board transfer system and game board production line - Google Patents

Description

  The present invention relates to a pallet conveyor for transporting a game board placed on a pallet truck in a game board production line for attaching an accessory to a game board of a pachinko machine.

  2. Description of the Related Art Conventionally, in a game board production line for pachinko machines, an operation of assembling various parts such as a windmill and a rail is generally performed using the same production line for a plurality of models. For this reason, the game board was mounted on the pallet cart which supports the four corners of the game board.

  However, in game boards, the mounting positions of parts such as nails, windmills, rails, etc. are concentrated in the center area of the plate, so in pallet trucks that only support the corners, the screws associated with the assembly work of the parts The central area of the game board may be bent due to pressing of the fastening machine, etc., and there is a possibility that poor assembly occurs.

  Therefore, in addition to the standard support parts at the four corners common to the game board, an air cylinder is provided corresponding to the uneven position on the back of the game board for each model, and the piston rod of this air cylinder is provided with the uneven on the back of the game board for each model. A pallet truck that has been expanded and contracted in response to the above has been proposed (Patent Document 1).

  Further, proposals have been made for an automatic screw tightening machine installed at a screw tightening work position of such a game board production line (Patent Documents 2 and 3).

  The automatic screw tightening machine disclosed in Patent Document 2 uses a double-acting air cylinder to advance a bit from a standby position toward a workpiece at a relatively high speed, and a screw on which a suction pipe covering the tip of the bit contacts the workpiece By detecting that the piston rod has been lowered to a predetermined height in the vicinity of the tightening start position and holding the piston rod with a deceleration brake to decelerate, it is considered that both the avoidance of breakage of screws and screw holes and high work efficiency are achieved.

The automatic screw tightening machine disclosed in Patent Document 3 is configured such that at the start of descending, both ends of the cylinder are exhausted by switching the direction switching valve, and the exhaust amount on the lower end side of the cylinder is suppressed by the flow control valve. When the sensor detects that the tip of the screw has entered the screw insertion hole of the workpiece, supply the air to the upper end of the cylinder by switching the direction switching valve. By lowering at a speed necessary for screw tightening, screw tightening is performed so that the tip of the screw is not damaged even if it contacts the surface of the workpiece.
JP 2003-300117 A JP-A-61-284335 JP-A-8-19923

  By the way, in recent years, a synthetic resin such as an acrylic board has been adopted as a game board of a pachinko machine. Such a synthetic resin game board has a thickness of about 10 mm, and has a problem that it is easy to bend compared to an earlier wood game board (about 19 mm in thickness).

  For this reason, in the control method of the automatic screw fastening machine of Patent Document 2, when the suction pipe comes into contact with the workpiece, the synthetic resin game board is subjected to a pressing force due to concentrated load, and there is a risk of bending. Further, in the control method of the automatic screw tightening machine of Patent Document 3, although only its own weight is applied at the stage where the screw tip enters the screw insertion hole, the screw is supplied while supplying air to project the driver unit. When tightening, the synthetic resin game board may be bent.

  In particular, not only the problem of the thickness of the synthetic resin game board, but also a large opening may be provided in the game board for the recent large-scale liquid crystal display and various productions. Since it is attached in the vicinity of such a large opening, it is desired to cope with the above-described problem of poor mounting due to the bending of the game board during screw tightening.

  In addition, in recent years, pachinko machines have a shorter interval for new product development, and variations in the shape and position of openings formed in game boards are increasing.

  For this reason, in the pallet truck of patent document 1, the optimal support state cannot be realized with respect to the shapes and positions of various openings formed in the game board. There is a problem that it is not possible to sufficiently cope with the occurrence.

  Therefore, an object of the present application is to eliminate mounting defects due to bending of the game board when, for example, an accessory is screwed and fixed with an automatic screwing machine.

A pallet conveyor for manufacturing a game board according to the present invention made to achieve the above object is a pallet conveyor for placing a pallet carriage on which a game board is placed and transporting it to a work position for attaching an accessory etc. And it is characterized by having the following composition.
(1) A support tool having the same support height as the back surface height of the game board placed on the pallet carriage is installed in the frame portion of the pallet conveyor in the vicinity of the work position.

  According to the pallet conveyor for manufacturing the game board of the present invention, the game board placed on the pallet truck carried to the work position is moved from the edge of the back surface by a support tool installed in the vicinity of the work position. It will be in the state supported also by the said support tool. Therefore, in the state where the position between the reference struts that are not normally supported by the pallet cart is also supported, the attachment of the accessory etc. to the game board will be performed, even if pressure at the time of screw tightening is applied, The game board becomes difficult to bend. As a result, it is possible to prevent an attachment failure of an accessory or the like.

Here, the pallet conveyor for manufacturing a game board of the present invention may be further configured as follows.
(2) The support is configured by a horizontal rotation member configured to be rotatable about a support column erected on the frame portion as a rotation center.

  The horizontal rotation member centering on the support of the frame part is rotated in the direction of the center of the game board every time the pallet truck on which the game board is placed is moved into the work position, and is released every time it is carried out. You may make it rotate manually or automatically so that it may rotate. Further, in order to support the four corners of the game board, the game board may be fixed in a state of being rotated in the center direction of the game board in advance as long as it does not interfere with the reference column provided on the pallet carriage. In the case of fixing in this way, it is advisable to use a reference stand that is erected on the pallet truck so as to support the inner side near the four corners of the game board. And it is good to make the front-end | tip of the horizontal rotation member rotated to the game board side support the edge of a game board on the outer side of these reference | standard support | pillars. In this case, the horizontal rotation member may be rotated to a rotation position such that the tip is directed to the front side in the direction of carrying the game board to the work position. As a result, even when the game board is brought into and out of the work position, even if the horizontal rotating member and the parts of the carriage on which the game board is placed come into contact with each other, Can be carried in and out. In particular, it is better to attach a torsion spring or the like to the rotation fulcrum so that it can escape from the pressing force to the outside.

  Here, the pallet conveyor for manufacturing the game board according to the present invention is further employed together with the pallet cart for game board having the following characteristics, thereby further preventing the game board from being bent and correctly correcting the objects. It becomes a game board conveyance system suitable for mounting.

In other words, the proposed game board transport system has a pallet truck for transporting the game board to a work position for mounting an accessory, and a pallet truck for mounting the accessory, etc. And a pallet conveyor for transporting to a work position, and also having the following configuration.
(11) The pallet carriage has the following configuration.
(11a) On the upper surface, a plurality of reference columns for horizontally supporting the back surface near the four corners of the game board are installed.
(11b) At least one (more preferably two or more) of the reference struts includes a fitting protrusion that fits into an alignment reference hole formed on the back surface of the game board.
(11c) A large number of support erection hole groups are provided in an area inside the reference support on the upper surface of the pallet carriage.
(11d) Using any of the holes in the support column standing hole group, an internal support column having the same support height as the reference support column is installed so that the position can be changed.
(12) The pallet conveyor has the following configuration.
(12a) A support tool having a support height equal to the back surface height of the game board placed on the pallet carriage is installed in the frame portion of the pallet conveyor near the work position.
(12b) The support is configured by a horizontal rotation member configured to be rotatable about a support column erected on the frame portion as a rotation center.

  According to the pallet truck having the configurations of (11a) to (11d), the game board is aligned with the reference column provided with the fitting protrusion, and is in a horizontal state supported by the reference column near the four corners. Can be placed. In addition, by using any one or more holes in the group of holes for standing columns to stand the inner column, the back surface on the center side of the game board is supported at the same height as the reference column. . As for the standing position of this internal strut, the position and shape of the opening formed in the game board, the mounting position of the accessory, etc. are selected by selecting and using the optimal one from the group of holes for standing the strut It can be set to the optimum position for each model according to. At this time, if there is a part that is attached to the back side of the game board, an internal column may be erected to directly support the back side of the game board while avoiding the position of the part. Near the position where there is a part that is attached to the back side, it is difficult to bend structurally by the attached part, and it is often the case that no additional object is attached to the upper surface of such a part. Even if the portion is not supported by the internal support, the object of preventing the deflection can be sufficiently achieved.

  Therefore, according to the pallet carriage having the configurations of (11a) to (11d), it is possible to sufficiently prevent the deflection and lock a necessary one at a necessary height by installing a large number of cylinders in advance. Compared to the technique of Patent Document 1 such as using the pallet truck, there is no waste, and there is an effect that a process for adjusting the cylinder height of the pallet truck and a wasteful facility such as providing the cylinder drive source to the pallet truck are not required. The

  Thus, not only the inside of the game board is firmly supported by the pallet carriage having the configuration of (11a to 11d), but also between the reference columns at the work position by the pallet conveyor having the configuration of (12a, 12b). By supporting the position from the edge with a support tool, the horizontal support state of the game board becomes more firm.

  As a result, when screws are tightened at the work position, the base of the pallet truck is near the four corners of the game board, the internal pillar of the pallet truck is inside, and near the side edge of the game board. Can be provided by a rotating support of the pallet conveyor, and can provide a game board transport system that does not cause bending that causes poor mounting at the work position.

  Further, the pallet conveyor for manufacturing the game board according to the present invention can be used together with the following game board screw tightening station in addition to the game board pallet carriage as described above, so that the game board can be further improved. It becomes a game board production line suitable for preventing the flexure and properly attaching the accessory.

That is, the proposed game board production line includes a pallet truck for transporting to a work position for mounting a game board and mounting an accessory, and a pallet truck for mounting an accessory etc. A pallet conveyor for transporting to a work position and a screw unit with a screw head engaged with the tip of a driver bit rotated by the driver unit by raising and lowering a driver unit of an automatic screw fastening machine installed at the work position. And a screw tightening control device that performs an operation of tightening and fixing the accessory and the like by tightening the game board, and further includes the following configuration.
(11) The pallet carriage has the following configuration.
(11a) On the upper surface, a plurality of reference columns for horizontally supporting the back surface near the four corners of the game board are installed.
(11b) At least one (more preferably two or more) of the reference struts includes a fitting protrusion that fits into an alignment reference hole formed on the back surface of the game board.
(11c) A large number of support erection hole groups are provided in an area inside the reference support on the upper surface of the pallet carriage.
(11d) Using any of the holes in the support column standing hole group, an internal support column having the same support height as the reference support column is installed so that the position can be changed.
(12) The pallet conveyor has the following configuration.
(12a) A support tool having a support height equal to the back surface height of the game board placed on the pallet carriage is installed in the frame portion of the pallet conveyor near the work position.
(12b) The support is configured by a horizontal rotation member configured to be rotatable about a support column erected on the frame portion as a rotation center.
(21) The automatic screw fastening machine has the following configuration.
(21a) An air cylinder that includes a descending air chamber and an ascending air chamber and that causes the piston rod, to which the driver unit is fixed, to move in a vertical direction, and a cylinder sensor that detects that the air cylinder has started to descend. Be prepared.
(21b) The switching valve for the descending air chamber of the air cylinder is configured to open when negative pressure is generated in the descending air chamber in a state where supply and discharge are stopped, and the driver unit The air cylinder has a weight sufficient to continue to descend even when the lowering air chamber of the air cylinder is stopped to supply and discharge and the ascending air chamber is exhausted.
(22) The screw tightening control device has the following configuration.
(22a) An air supply / discharge switching device that switches the lowering air chamber and the rising air chamber of the air cylinder to any of supply, supply / discharge stop, and exhaust, and a drive device that stops driving the driver unit. Be prepared.
(23) The screw tightening control device executes the following control.
(23a) With respect to the air supply / discharge switching device, after the exhaust side air chamber of the air cylinder is exhausted and the lower side air chamber is supplied, the lower side air chamber is supplied when the cylinder sensor detects the start of lowering. The exhaust stop is performed, and after the screwing is completed, the air supply / discharge operation is performed in which the rising air chamber is supplied and the lower air chamber is exhausted.

  According to the game board production line adopting such a configuration, when tightening the screw by the automatic screw tightening machine, after giving the lowering by the air supply to the lower side air chamber, it is lowered by the driver unit's own weight, Even after screwing starts, the screw is tightened by the driver unit's own weight. Therefore, a strong concentrated load is not applied to the game board, and a mounting failure due to bending does not occur. In this descent due to its own weight, the descent-side air chamber is in a supply / exhaust stop state, not exhaust, so it slowly descends according to the air flowing in from the switching valve according to the negative pressure, and does not fall at a stretch . Therefore, even if the driver unit's own weight is increased so as to apply a sufficient pressure for screwing, the screw does not collide strongly against the game board.

  And in the game board manufacturing line concerning this proposal, the game board was aligned by the reference | standard support | pillar provided with the fitting protrusion by the pallet cart provided with the structure of (11a)-(11d) at the time of screw fastening. In the state, not only was it placed in a horizontal state where the four corners were supported by the reference struts, but also the openings that were easily bent by the internal struts that were erected using any of the holes for the strut standing hole groups, etc. In addition to being supported so that the near back surface is kept in a horizontal state, it is supported by the pallet conveyor having the configuration of (12a) and (12b) so that the back surface of the edge between the reference columns is also maintained in a horizontal state. Therefore, for example, when an accessory is screwed and fixed to an acrylic board game board having a thickness of 10 mm, an attachment failure due to bending does not occur.

Here, in the game board transport system and the game board production line proposed above, the pallet truck having the configurations (11a) to (11d) may further include the following configurations.
(11e) The internal support column is installed via a horizontal arm that is rotatably attached to any hole of the support column erection hole group.

  By adopting such a configuration as well, the internal support can be erected at an arbitrary position within a predetermined rotation range centered on the support erection hole, and the shape of the game board for each model can be more flexible. And optimal support according to the structure.

In this case, the following configuration may be further provided.
(11f) The horizontal arm is provided with a long hole extending in the axial direction as a support shaft insertion hole for rotatably supporting a hole in any of the group of holes for standing upright with a bolt or the like. Being.

  By adopting such a configuration, the pivoting radius of the horizontal arm centered on the column erection hole can be changed arbitrarily by the length of the long hole, so that the internal column can be erected. The range can be made wider.

The pallet truck including the configurations (11a) to (11d), (11a) to (11e), or (11a) to (11f) may further include the following configuration.
(11g) The reference column provided with the fitting protrusion is installed at a diagonal position.
(11h) The column support hole groups are set up at regular intervals on a straight line extending from the center of the reference column toward the opposite side edge.

  Since the holes for standing columns are formed at equiangular angles on a straight line from the position near the positioning position by the reference strut with the fitting protrusion, positioning of the support position by the internal strut becomes easy. When (11e) and (11f) are also provided, it is possible to more accurately and accurately install the internal support column at a position where each model is easy to bend.

In the proposed game board production line, it is also desirable to change the configurations (21) to (23) to the more specific configurations (31) to (33) below.
(31) The automatic screw fastening machine has the following configuration.
(31a) An air cylinder that includes a descending air chamber and an ascending air chamber and that causes the piston rod, to which the driver unit is fixed, to move in a vertical direction, and a cylinder sensor that detects that the air cylinder has started to descend. Be prepared.
(31b) The switching valve of the lowering air chamber of the air cylinder is configured to open when negative pressure is generated in the lowering air chamber in a state where supply and discharge are stopped, and the driver unit includes: The air cylinder has a weight sufficient to continue to descend even when the lowering air chamber of the air cylinder is stopped to supply and discharge and the ascending air chamber is exhausted.
(31c) a first height sensor for detecting that the driver unit has been lowered to a tightening start height, a second height sensor for detecting that the driver unit has been lowered to a tightening completion height, and the driver A torque sensor for detecting that tightening completion torque has been generated in the unit.
(32) The screw tightening control device has the following configuration.
(32a) An air supply / discharge switching device that switches the lowering air chamber and the rising air chamber of the air cylinder to any of supply, supply / discharge stop, and exhaust, and a drive device that stops driving the driver unit. Be prepared.
(33) The screw tightening control device executes the following control.
(33a) Supplying the descending air chamber to the air supply / discharge switching device when the ascending side air chamber of the air cylinder is exhausted and the descending side air chamber is supplied and the cylinder sensor detects the start of descending. After that, when the second height sensor detects a drop to the tightening start height, the air chamber on the ascending side of the air cylinder is turned on and off, and the torque sensor generates the screwing completion torque. When it is detected, control is performed to perform an air supply / discharge operation that supplies the rising air chamber and exhausts the falling air chamber.
(33b) When the second height sensor detects the lowering to the tightening start height with respect to the drive device, the tightening operation is started, and when the torque sensor detects the occurrence of the tightening completion torque, the tightening is performed. Execute control to stop operation.

  Here, the “tightening start height” means “the height at which a slight amount immediately before the completion of screwing begins to be tightened strongly”, and the height at which the screw begins to enter the screw hole formed in the game board. is not. Accordingly, before the “tightening operation” of (33b) is performed, the “operation of intruding into the screw hole while rotating the screw” is started. By replacing this configuration, in addition to the actions and effects described above, the screwing operation is stopped after the tightening completion torque has been detected and the tightening completion torque has been detected. It is possible to avoid the shortage of screwing.

Furthermore, in the proposed game board production line, it is desirable that the configurations (21) to (23) are further changed to the following specific configurations (41) to (43).
(41) The automatic screw fastening machine has the following configuration.
(41a) a chucking claw biased in a closing direction so as to form a screw receiving space between a suction pipe disposed around the tip end side of the driver bit, and a lower end of the suction pipe; and the screw A screw supply device for supplying screws such that the screw head is held by the chuck claws with respect to the receiving space;
(41b) An air cylinder that includes a descending air chamber and an ascending air chamber and that causes the piston rod, to which the driver unit is fixed, to move in a vertical direction, and a cylinder sensor that detects that the air cylinder has started to descend. Be prepared.
(41c) a first height sensor for detecting that the tip of the driver bit has been lowered from the tip of the suction pipe to a position away from the tip of the countersunk screw; and the tip of the driver bit is the tip of the suction pipe A second height sensor for detecting that the tip has been lowered to the tip position;
(41d) The switching valve for the lowering air chamber of the air cylinder is configured to open when negative pressure is generated in the lowering air chamber in a state where supply and discharge are stopped, and the driver unit is A torque sensor for detecting that a tightening completion torque has been generated and has a weight sufficient to continue to descend even when the lower air chamber of the air cylinder is stopped to supply and discharge and the upper air chamber is exhausted; Be prepared.
(42) The screw tightening control device has the following configuration.
(42a) An air supply / discharge switching device that switches the lowering air chamber and the rising air chamber of the air cylinder to any one of supply, supply / discharge stop, and exhaust, and the suction pipe is in a screw adsorption state by air. A suction device and a drive device capable of switching the rotational speed at least between high speed rotation and low speed rotation with respect to the driver unit;
(43) The screw tightening control device executes the following control.
(43a) With respect to the air supply / discharge switching device, after the exhaust side air chamber of the air cylinder is exhausted and the lower side air chamber is supplied, the lower side air chamber is supplied when the cylinder sensor detects the start of lowering. When the detection signal from the second height sensor is input, the ascending side air chamber of the air cylinder is stopped when supply and discharge is stopped. Further, when the torque sensor detects the occurrence of tightening completion torque, Control to perform air supply / exhaust operation that supplies the rising air chamber and exhausts the falling air chamber.
(43b) The drive device is rotated at a high speed from when the lower air chamber is supplied to when the detection signal by the first height sensor is input, and by the first height sensor. When the detection signal is input, control is performed to switch to low speed rotation and stop when the torque sensor detects the occurrence of tightening completion torque.
(43c) Detecting by the first height sensor by causing the adsorption device to perform an adsorption operation after supplying the descending air chamber and before inputting a detection signal by the first height sensor. Execute the control to stop the suction when the signal is input.

  By replacing with such a configuration, in addition to the above-described functions and effects, the following functions and effects are further exhibited. First, by lowering the driver unit at a high speed, the screw engaged with the tip of the driver bit can be lowered in the screw receiving space formed between the suction pipe and the chuck claw. . When the head of the countersunk screw is lowered to a height to be tightened, the driver unit is switched to low speed rotation. As a result, at the start of tightening, the rotational torque can be increased by rotating at a low speed so that reliable tightening can be performed. Then, when the second height sensor outputs a predetermined detection signal, the ascending air chamber is brought into the air supply / discharge stop state, so that the driver unit does not receive excessive weight. The screw is securely tightened by the detection by the second height sensor and the detection by the torque sensor, and the problem of insufficient screwing does not occur.

According to the present invention, it is possible to eliminate mounting defects due to bending of the game board when, for example, an accessory is screwed and fixed to the game board with an automatic screw tightening machine.

  Hereinafter, a game board screw fastening facility according to an embodiment of the present invention will be described in detail with reference to the drawings.

  As shown in FIG. 1, the game board screw tightening facility of the embodiment includes a pallet conveyor 10 that places the game board 1 on the pallet carriage 3 and conveys it to the screw tightening station S.

  The pallet conveyor 10 has a structure in which a support 12 having the same support height as the back surface height of the game board 1 placed on the pallet carriage 3 is installed in the frame portion 11 at the screw fastening station S.

  The support 12 is constituted by a horizontal rotation member 14 configured to be rotatable about a support column 13 erected on the frame portion 11 as a rotation center. The horizontal rotation member 14 is rotated in the central direction of the game board 1 each time the pallet truck 3 on which the game board 1 is placed is carried into the work position, and is rotated outward every time it is carried out. It is automatically controlled.

  As shown in FIG. 2, the pallet cart 3 is provided with a plurality of reference columns 31 to 39 that horizontally support the back surface near the four corners of the game board 1 on the upper surface thereof. Among these plurality of reference struts, three indicated by reference numerals 31 to 33 are provided with fitting protrusions 31 a to 33 a that fit into alignment reference holes formed on the back surface of the game board 1.

  Further, as shown in FIGS. 2 and 3, the pallet carriage 3 is provided with a plurality of support erection holes 41 a to 41 j in the range inside the reference supports 31 to 39 as shown in FIGS. 2 and 3. And the internal support | pillars 50 and 50 which become the reference | standard support | pillars 31-39 and the same support height are installed using either of these support | pillar standing holes 41a-41j.

  The reference struts 31 and 32 having the fitting protrusions 31a and 32a and the reference strut 33 having the fitting protrusions 33a are installed at positions that are substantially diagonal in the upper left and lower right in the figure. Further, the pillar standing holes 41a to 41j are formed at equal intervals on a straight line extending from the center of the reference pillars 32 and 33 toward the opposite side edge.

  Here, the pallet truck 3 of the present embodiment includes one of the three reference columns 31 and 32 in the upper left of the three reference columns 31 to 33 and one reference in the lower right of the drawing. The game board 1 is positioned using the support 33. As shown in FIG. 18A, the reference strut 32 on the right side of the two upper left reference struts 31 and 32 has a structure in which the fitting protrusion 32a is immersed when the knob 32c is pulled. That is, as shown in FIG. 18 (A), the normal-sized game board 1normal is used for positioning the upper left corner with the fitting protrusion 32a of the reference strut 32 on the right side of the upper left two protruding. As shown in the figure (B), the large-sized game board 1large is used for positioning the upper left corner of the reference strut 31 on the left side with the fitting protrusion 32a immersed therein. Note that, as shown in FIG. 18A, the normal size gaming board 1normal has a shape that is not supported by the left reference column 31 because of the notch shape.

  The internal strut 50 described above includes a horizontal arm 51 rotatably attached to any one of the strut standing holes 41a to 41j, a strut 52 erected on the tip side of the horizontal arm 51, The position of the column 52 is such that the position of the column 52 can be changed.

  Therefore, the internal support column 50 can be set up at an arbitrary position within the rotation range centered on the support column setting holes 41a to 41j, and can be flexibly adapted to the shape and structure of the game board 1 for each model. Optimal support is possible.

  Here, the horizontal arm 51 is formed with a long hole 56 extending in the longitudinal direction of the arm in order to insert a bolt 55 serving as a support shaft. Therefore, the position of the internal support 50 can be changed not only by rotation, but also the rotation radius of the horizontal arm 51 can be arbitrarily changed by the length of the long hole 56. The range in which the column can be erected using the column erection holes 41a to 41j is wider.

  Further, since the support column standing holes 41a to 41j are formed at equal intervals on a straight line from the vicinity of the positioning position by the reference support columns 32 and 33 including the fitting protrusions 32a and 33a, the support position by the internal support column 50 is supported. Therefore, the internal support 50 can be erected accurately and accurately at a position where it is easy to bend due to the presence of an opening for each model.

  Here, the support 12 installed on the frame portion 11 of the pallet conveyor 10 is unloaded by manually rotating the horizontal rotation member 14 in the center direction of the game board every time the pallet carriage 3 is carried into the work position. You may use it so that the horizontal rotation member 14 may be rotated manually every time. In addition, in order to support the four corners of the game board 1, a state in which the horizontal rotation member 14 is previously rotated in the center direction of the game board within a range that does not interfere with any of the reference columns 31 to 39 provided on the pallet carriage 3. It may be fixed to. In this case, the horizontal rotation member 14 may be rotated to a rotation position such that the tip is directed to the front side in the direction in which the game board 1 is carried into the work position. As a result, even when the game board 1 is brought into the work position and is taken out from the work position, even if it contacts the horizontal turning member 14 and the harness or the like coming out of the game board 1, the game board 1 smoothly. Carry in / out. In particular, it is better to attach a torsion spring or the like to the rotation fulcrum so that it can escape from the pressing force to the outside.

  Also, as shown in FIG. 4, a vertical plate 21 is attached to the frame portion 11 of the pallet conveyor 10, and a plurality of (two in this example) rollers 22 are projected from the vertical plate 21 to the inside of the conveyor line. , 22 may be attached, and a fixed support tool installed such that the upper ends of the rollers 22, 22 are the same height as the support height of the reference column 31 or the like may be used. In this case, the amount of protrusion of the rollers 22 and 22 is set so as to be within a range that does not interfere with any of the reference columns 31 to 39 provided on the pallet carriage 3.

  The screw fastening station S is provided with an automatic screw fastening machine 100 having the following configuration.

  As shown in FIGS. 5 to 10, the automatic screwing machine 100 forms a screw receiving space between the suction pipe 102 disposed around the front end side of the driver bit 101 and the lower end of the suction pipe 102. A chuck claw 103 that is biased in the closing direction, and a screw supply device 104 that supplies the screw 2 so that the screw claw 103 is held by the screw claw upward with respect to the screw receiving space.

  The automatic screw tightening machine 100 includes a descending air chamber and an ascending air chamber, and an air cylinder 112 that moves the piston rod 111, to which the driver unit 105 is fixed, in a vertical direction, and the air cylinder 112 starts to descend. And a cylinder sensor 113 for detecting this.

  Further, the automatic screw tightening machine 100 includes a first height sensor 121 that detects that the tip of the driver bit 101 is lowered from the tip of the suction pipe 102 to a position separated from the tip of the countersunk screw 2, and the driver bit 101. And a second height sensor 122 that detects that the tip has been lowered to the tip position of the suction pipe 102. Note that a detected portion 122 a for the second height sensor 122 to detect the height is attached to the rotating shaft 107 of the driver bit 101. In addition, a detected portion 121 a for the first height sensor 121 to detect the height is also attached to the first height detection rod 106 that descends together with the driver unit 105 independently of the suction pipe 102. .

  The switching valve for the lowering air chamber of the air cylinder 112 is structured such that when a negative pressure is generated in the lowering air chamber in a state where supply and discharge are stopped, the valve is slightly opened according to the negative pressure. The driver unit 105 has a weight sufficient to keep the descent when the lower air chamber of the air cylinder 112 is turned on and off, and the ascending air chamber is exhausted, and the tightening completion torque is generated. The torque sensor 123 (refer FIG. 11) which detects this is provided.

  Further, as shown in FIG. 11, the automatic screw tightening machine 100 is an air supply / discharge switching device that switches the lowering air chamber and the rising air chamber of the air cylinder 112 to any of supply, supply / discharge stop, and exhaust. 131, a suction device 132 that puts the suction pipe 102 in a screw suction state by air, and a motor driver 133 that can switch the rotational speed at least between high-speed rotation and low-speed rotation with respect to the driver unit 105.

  In the automatic screw tightening machine 100 configured in this way, the timing of the raising / lowering and rotation driving of the driver unit 105 is controlled by a screw tightening control device 200 (see FIG. 11) having the following configuration.

  The screw tightening control apparatus 200 exhausts the rising side air chamber of the air cylinder 112 and supplies the descending side air chamber to the air supply / exhaust switching device 131, and when the cylinder sensor 113 detects the descending start, the falling side air chamber When the second height sensor 122 outputs a detection signal, the ascending air chamber of the air cylinder 112 is stopped when the chamber is turned on and off. Further, when the torque sensor 123 detects the occurrence of the tightening completion torque. Control is performed to perform an air supply / exhaust operation that supplies the ascending air chamber and exhausts the descending air chamber.

  Further, the screw tightening control device 200 makes the motor driver 133 rotate at a high speed between the time when the lower air chamber is supplied and the time when the first height sensor 121 outputs a detection signal. When the sensor 122 outputs a detection signal, control is performed to switch to low speed rotation, and when the torque sensor 123 detects the occurrence of tightening completion torque, control is performed to stop.

  Furthermore, the screw tightening control device 200 causes the suction device 132 to perform a suction operation between the time when the lower side air chamber is supplied and the time when the first height sensor 121 outputs a detection signal. When the sensor 121 outputs a detection signal, control for stopping the suction is executed.

  This game board screw fastening facility is controlled by a control system as shown in FIG. Management data for game board manufacturing is input to the main controller 300. The main control device 300 is configured to communicate with the screw tightening control device 200 and the transport control device 400. Detection signals are input from the cylinder sensor 113, the first height sensor 121, the second height sensor 122, and the torque sensor 123 to the screw tightening control device 200. Then, the screw tightening control device 200 is transferred to the screw supply device 104, the air supply / discharge switching device 131, the suction device 132, the motor driver 133, and the X motor 134 and the Y motor 135 that move the base of the automatic screw tightening machine 100. And a control signal are output, and an operation completion signal from these control target devices is also input. On the other hand, the conveyance control device 400 includes a stopper sensor 411 that detects that the pallet carriage 3 has come into contact with a stopper member (not shown) of the screw fastening station S, and a game board detection sensor group arranged along the conveyance line. A detection signal from 412 is input. The stopper member is also provided immediately before the screw tightening station S, and is configured to wait for the next pallet truck immediately before the screw tightening station S. Then, the transfer control device 400 includes a transfer motor 421 for executing the transfer operation by the pallet conveyor 10, an air cylinder 431 for retracting the stopper member of the screw fastening station S, and a stopper member immediately before the screw fastening station S. A control signal is output to the air cylinder 432 for appearing and disappearing, and an operation completion signal and the like from these control target devices are also input.

  Next, the control operation performed by the game board screw tightening facility of the present embodiment will be described based on the flowcharts of FIGS. As shown in the main flow of FIG. 12, the main control device 300 first causes the transfer control device 400 to execute carry-in control for positioning the game board 1 at the screw tightening station S and setting the screw tightening start state. (S1). When a positioning completion signal is returned from the transfer control device 400 (S2: YES), the screw tightening control device 200 is instructed to start a screw tightening operation (S3). When a screw tightening completion signal is returned from the screw tightening control device 200 (S4: YES), it is determined whether or not there is a next game board (S5). If there is a next game board (S5: YES), the transport control device 400 is instructed to carry out the game board that has been screw-tightened from the screw-fastening station S0 and to start the carry-out / load-in operation for carrying in the next game board (S6). When the signal indicating that the next game board has been positioned is returned from the transfer control device 400 (S7: YES), the process returns to S3 to instruct the screw tightening control device 200 to start the screw tightening operation. . On the other hand, when it is determined in S5 that there is no next game board (S5: NO), the carry control device 400 is instructed to carry out the game board (S8).

  As shown in FIG. 13, when a command for a carry-in operation is input from the main control device 300 (S10: YES), the transport control device 400 causes the air cylinder 431 to stroke in the projecting direction to bring the stopper member into the projecting state. (S11). Then, the transport motor 421 is driven to execute a transport operation (S12). When a detection signal indicating that the pallet truck 3 is in contact with the stopper member is input from the stopper sensor 411 (S13: YES), the transport motor 421 is stopped (S14), and the main control device 300 is stopped. In response to this, a positioning completion signal is output (S15).

  On the other hand, when the command from the main controller 300 is a carry-out / carry-in operation (S10: NO, S20: YES), as shown in FIG. 14, the air cylinder 432 for protruding and retracting the stopper member immediately before the screw fastening station is projected. The air cylinder 431 for retracting and retracting the stopper member of the screw fastening station S is stroked in the retracting direction (S22). Subsequently, the transport motor 421 is driven to cause the pallet conveyor 10 to start a transport operation (S23). Then, it is determined whether or not the pallet truck 3 has been unloaded from the screw fastening station S based on a detection signal from a sensor downstream of the screw fastening station S in the game board detection sensor group 412 (S24). If it is determined that the unloading has been completed (S24: YES), the air cylinder 431 is stroked in the protruding direction to bring the stopper member of the screw fastening station S into the protruding state (S25), and the air cylinder 432 is stroked in the immersing direction. The next pallet truck that has been waiting just before the fastening station S is brought into a state where it can be moved to the screw fastening station S (S26). Thereafter, when a detection signal indicating that the pallet truck 3 is in contact with the stopper member of the screw fastening station S is input from the stopper sensor 411 (S27: YES), the conveyance motor 421 is stopped (S28). Then, the air cylinder 432 is stroked in the protruding direction to protrude the stopper member immediately before the screw fastening station S (S29). Then, a carry-out / carry-in completion signal is output to the main controller 300 (S31).

  In addition, since the conveyance motor 421 has been described here as one, it is assumed that the next pallet truck that has come into contact with the stopper immediately before the screw fastening station S during the carry-out operation is stopped in an idle state. The pallet conveyor 10 is divided into a plurality of sections in the length direction and managed, and a conveyance motor is installed on the upstream side of the screw fastening station S, the screw fastening station S, and the downstream side, and immediately before the screw fastening station S. When the next pallet carriage comes into contact with this stopper, the upstream conveying motor can be stopped. In this case, it may be configured to resume the conveyance by the upstream conveyance motor following the processing of S25 and S26.

  On the other hand, when the command from the main control device 300 is an unloading operation (S10, S20: NO), as shown in FIG. 15, the air cylinder 431 is stroked in the immersion direction to stop the screw fastening station S. Is brought into an immersive state (S41), and the carry motor 421 is driven to execute a carry-out operation (S43). Then, it is determined whether or not the pallet truck 3 has been unloaded from the transfer line based on a detection signal from a sensor downstream of the screw tightening station S in the game board detection sensor group 412 (S44). If it is determined that the process is finished (S44: YES), the transport motor 421 is stopped (S45).

  As shown in FIG. 16, when a screw tightening start command is input from the main control device 300 (S100: YES), the screw tightening control device 200 receives the X motor 134 for moving in the vertical axis direction and the horizontal axis moving command. The Y motor 135 is driven to move the automatic screw tightening machine 100 to a screw tightening position (a position where the axis of the driver bit 101 is directly above the screw hole 1c) (S101). When a movement completion signal to the screw tightening position is input (S102: YES), the screw supply device 104 is instructed to supply the screw 2 (S103).

  By the above operation, as shown in FIG. 5, the automatic screw tightening machine 100 is moved XY to the screw tightening position and the screw 2 is supplied to complete the screw tightening start preparation.

  Next, the air supply / discharge switching device 131 outputs a command for operating the switching valve for the rising air chamber to exhaust and the switching valve for the lowering air chamber to supply (S111), and to the adsorption device 132. Then, the suction operation is commanded (S112), and the motor driver 133 is commanded to rotate at high speed (S113).

  With the above operation, as shown in FIG. 6, the screw 2 is held by the driver bit 101 and is centered.

  When a descent start signal is input from the cylinder sensor 113 (S121: YES), a command for switching the descent side air chamber switching valve to the supply / discharge stop is output to the air supply / discharge device 131 (S122).

  By the above operation, as shown in FIGS. 7 and 8, the driver bit 101 is lowered together with the suction pipe 102, pushes the chuck claws 103, 103 to reach the upper surface of the game board 1, and the screw 2 reaches the upper surface of the game board 1. The screw is made to enter the screw hole 1c formed in 1. The illustrated example shows an acrylic board game board, and the screw hole 1c is formed as a through hole. In the case of a wood game board, not a through-hole but a depression by a punch or the like is formed, and a screw 2 is screwed into this depression.

  After that, the detected part 121a is lowered to the first detection height Lvel1 (see FIG. 9C), and when a detection signal is input from the first height sensor 121 (S131: YES), the motor driver 133 is Then, the switching to the low speed rotation is commanded (S132).

  With the above operation, tightening of the screw 2 is started as shown in FIG.

  After that, the detected portion 122a descends to the second detection height Lvel2 (see FIG. 10C), and when a detection signal is input from the second height sensor 122 (S141: YES), the air supply / discharge switching device 131. In response to this, a command for operating the switching valve of the ascending air chamber to stop supplying and discharging is output (S142).

  When the torque sensor 123 detects the occurrence of the tightening completion torque (S151: YES), it instructs the motor driver 133 to stop (S152). With the above operation, the tightening of the screw 2 is completed as shown in FIG.

  Thereafter, a command is supplied to the air supply / discharge switching device 131 to perform an operation of supplying the switching valve for the rising air chamber and exhausting the switching valve for the falling air chamber (S153).

  Then, when a lift completion signal is input from the cylinder sensor 113 (S161: YES), it is determined whether there is a next screw tightening position (S162). If there is a next screw tightening position (S162: YES), the process returns to S101. On the other hand, if there is no next screw tightening position (S162: NO), a screw tightening completion signal is output (S163).

  If the above control process is made into a timing chart, as shown in FIG. 17, when the supply of the descending air and the exhaust of the ascending air of the air cylinder 112 are started at time t1, the cylinder rod 111 starts to descend. At time t1, screw adsorption and high-speed driver rotation are also started.

  When the cylinder sensor 113 is turned off at time t2 and the start of lowering can be confirmed, the lowering air supply is stopped, and the lowering air chamber is brought into a supply / discharge stop state. Here, since the switching valve of the descending air chamber is structured to open by negative pressure, the air gradually flows into the descending air chamber in balance with the own weight of the driver unit 105 and slowly descends. Go.

  When the first height sensor 121 is turned on at time t3, the driver rotation speed is switched to a low speed. Also, the screw adsorption is stopped. This state corresponds to a state in which the plate portion of the head of the screw 2 is tightened from now on. Therefore, after this, the cylinder rod 111 is further lowered by the amount of the head of the screw 2, but the inclination of the descending line of the cylinder rod 111 becomes gentler because of the low speed rotation.

  When the second height sensor 122 is turned on at time t4, the ascending air chamber of the cylinder 112 is stopped to supply and discharge. As a result, the driver unit 105 does not descend any further. Then, when the torque sensor 123 is turned on at time t5, the rotation of the driver bit 101 is stopped. During the time t4 to t5, the cylinder rod 111 does not descend for control, but the screw 2 continues to be screwed to tighten the plate portion while the driver bit 101 rotates. In this embodiment, since the driver unit 105 itself has a sufficient weight, the actual height of the cylinder rod 111 is slightly corresponding to the tightening of the screw 2 during the time t4 to t5. It is descending. Then, at time t6 when the driver bit 101 stops, the descending air chamber is exhausted and the ascending air chamber is supplied, so that the cylinder rod 111 is quickly raised. Immediately after the cylinder sensor 113 is turned ON, both the descending and ascending air chambers are brought into a supply / discharge stop state.

  Since it comprised as mentioned above, in the pallet conveyor 10 of embodiment, the game board 1 mounted in the pallet cart 3 carried in to the screw fastening station S is back surface by the support tool installed in the work position vicinity. A predetermined range from the edge is supported by the support. Accordingly, in the state where the position between the reference struts that are not normally supported by the pallet carriage 3 is also supported, the accessory or the like is attached to the game board 1, and even if the pressure at the time of screw tightening is applied. The game board 1 becomes difficult to bend. As a result, it is possible to prevent an attachment failure of an accessory or the like.

  In addition, according to the pallet carriage 3 employed in the embodiment, the game board is erected by using the one or more holes among the erection holes 41a to 41j to erect the internal strut 50, The back surface on the center side of the game board is supported at the same height as the reference columns 31-39. As for the standing position of the internal support 50, the position and shape of the opening formed in the game board 1 can be selected by selecting and using the hole at the optimum position from among the numerous support holes 41a to 41j. It can be set to an optimum position for each model according to the attachment position of the accessory. At this time, if there is a part that is attached to the back of the game board 1, the internal support 50 may be erected to directly support the back of the game board while avoiding the position of the part.

  In particular, since the internal support column 50 is attached via the horizontal arm 51 provided with the long hole 56, the internal support column 50 is erected at an arbitrary position within a predetermined rotation range around the support column standing holes 41a to 41j. This enables more flexible and optimal support according to the shape and structure of the game board for each model. In addition, the number of holes to be formed in the pallet carriage 3 can be reduced despite the fact that support at an arbitrary position is possible.

  In addition, since the pillar standing holes 41a to 41j are formed at equal intervals on a straight line extending from the center of the reference pillars 32 and 33 toward the opposite side edge, positioning of the support position by the internal pillar is possible. Installation of the internal support column 50 at an easy and flexible position for each model can be carried out more accurately and accurately.

  On the other hand, according to the screw tightening station of the embodiment, when the screw 2 is tightened by the automatic screw tightening machine 100, after the lowering is given by the air supply to the lower side air chamber, the driver unit 105 descends by its own weight. Even after the screwing is started, the screw tightening is executed by the weight of the driver unit 105. Therefore, a strong concentrated load is not applied to the game board 1 and no mounting failure due to bending occurs. In addition, when descending under its own weight, the descending air chamber is in a supply / exhaust stop state, not exhaust, so it slowly descends by the amount of air slightly flowing in from the switching valve according to the negative pressure and descends all at once. There is no. Therefore, even if the driver unit 105 is increased in weight so as to apply a sufficient pressure for screwing, the screw 2 does not collide strongly with the game board 1.

  In addition, since the screwing operation is stopped after detecting that the tightening completion height has been reached and the tightening completion torque has been generated, it is possible to ensure that the screw is screwed in securely, and to avoid insufficient screwing. be able to.

  Furthermore, first, the screw 2 engaged with the tip of the driver bit 101 is centered in the screw receiving space formed between the suction pipe 102 and the chuck claw 103 by lowering the driver unit 105 at high speed. Can be lowered. Then, when the head of the countersunk screw 2 is lowered to a height to be tightened, the driver unit 105 is switched to low speed rotation. As a result, at the start of tightening, the rotational torque can be increased by rotating at a low speed so that reliable tightening can be performed. When the second height sensor 122 outputs a predetermined detection signal, the ascending-side air chamber is brought into an air supply / discharge stop state, so that the driver unit 105 does not receive excessive weight. The screw 2 is securely tightened by the detection by the second height sensor 122 and the detection by the torque sensor 123, and there is no problem of insufficient screwing.

  Although one embodiment as the best mode for carrying out the invention has been described above, the present invention is not limited to this, and various modifications can be made without departing from the scope of the invention.

It is a top view of the game board manufacturing equipment of an embodiment. The pallet trolley | bogie of embodiment is shown, (A) is a top view, (B) is a right view, (C) is a front view, (D) is a top view of an internal support | pillar, (E) is a partial cross section of an internal support | pillar It is a front view shown by. It is a top view of the pallet truck of an embodiment. It is a top view which shows the modification about the support tool provided in a pallet conveyor. The automatic screw fastening machine in embodiment is shown, (A) is a front view, (B) is a side view, (C) is an AA end view. The automatic screw fastening machine in embodiment is shown, (A) is a front view, (B) is a side view. The automatic screw fastening machine in embodiment is shown, (A) is a front view, (B) is a side view. The automatic screw fastening machine in embodiment is shown, (A) is a front view, (B) is a side view, (C) is an enlarged side view of the principal part. The automatic screw fastening machine in embodiment is shown, (A) is a front view, (B) is a side view, (C), (D) is an enlarged side view of the principal part. The automatic screw fastening machine in embodiment is shown, (A) is a front view, (B) is a side view, (C), (D) is an enlarged side view of the principal part. It is a block diagram which shows the control system of embodiment. It is a flowchart which shows the main flow of embodiment. It is a flowchart which shows the conveyance control flow of embodiment. It is a flowchart which shows the conveyance control flow of embodiment. It is a flowchart which shows the conveyance control flow of embodiment. It is a flowchart which shows the screw fastening flow of embodiment. It is a timing chart of the screw fastening flow of an embodiment. The usage method of the pallet trolley | bogie of embodiment is shown, (A) is explanatory drawing in the case of supporting a normal size game board, (B) is explanatory drawing in the case of supporting a large size game board.

Explanation of symbols

S ... Screw tightening station 1 ... Game board 2 ... Screw 3 ... Pallet cart 10 ... Pallet conveyor 11 ... Frame part 12 ... Supporting tool 13 ... Post 14 ... · Horizontal rotating member 21 ··· Vertical plate 22 ··· Rollers 31 to 39 ··· Reference struts 31a to 33a · Fitting protrusions 41a to 41j · · Post 51 ... Horizontal arm 52 ... Post 53 ... Resin cap 55 ... Bolt 56 ... Long hole 100 ... Automatic screwing machine 101 ... Driver bit 102 ... Adsorption pipe DESCRIPTION OF SYMBOLS 103 ... Chuck claw 104 ... Screw supply device 105 ... Driver unit 106 ... First height detection rod 107 ... Rotating shaft 111 ... Piston rod 112 ... Air cylinder 113 ... Cylinder sensor 121 ... 1st height sensor 121a ... 1st height detected part 122 ... 2nd height sensor 122a ... 2nd height detected part 123 ... Torque sensor 131 ... Air supply / discharge switching device 132 ... Adsorption device 133 ... Motor driver 134 ... X motor 135 ... Y motor 200 ... Screw tightening control device 300 ... Main control device 400: Transport control device 411: Stopper sensor 412: Game board detection sensor group 421: Transport motor 431, 432: Air cylinder

Claims (4)

A pallet conveyor for placing a pallet carriage on which a game board is placed and transporting the pallet carriage to a work position for attaching an accessory, etc., and having the following configuration, a pallet for manufacturing a game board Conveyor.
(1) A support tool having the same support height as the back surface height of the game board placed on the pallet carriage is installed in the frame portion of the pallet conveyor in the vicinity of the work position. The pallet conveyor for manufacturing a game board according to claim 1, further comprising the following configuration.
(2) The support is configured by a horizontal rotation member configured to be rotatable about a support column erected on the frame portion as a rotation center. A pallet carriage for placing the game board and transporting it to the work position for attaching the accessory, and a pallet conveyor for placing the pallet carriage and transporting it to the work position for attaching the accessory etc. A game board conveying system characterized by comprising the following configuration.
(11) The pallet carriage has the following configuration.
(11a) On the upper surface, a plurality of reference columns for horizontally supporting the back surface near the four corners of the game board are installed.
(11b) At least one of the reference struts has a fitting protrusion that fits into an alignment reference hole formed on the back of the game board.
(11c) A large number of support erection hole groups are provided in an area inside the reference support on the upper surface of the pallet carriage.
(11d) Using any of the holes in the support column standing hole group, an internal support column having the same support height as the reference support column is installed so that the position can be changed.
(12) The pallet conveyor has the following configuration.
(12a) A support tool having a support height equal to the back surface height of the game board placed on the pallet carriage is installed in the frame portion of the pallet conveyor near the work position.
(12b) The support is configured by a horizontal rotation member configured to be rotatable about a support column erected on the frame portion as a rotation center. A pallet truck for placing the game board and transporting it to a work position for attaching a feature, a pallet conveyor for placing the pallet truck and transporting it to a work position for attaching a feature, etc., The driver unit of the automatic screw tightening machine installed at the work position is raised and lowered, and the screw having the screw head engaged with the tip of the driver bit rotated by the driver unit is tightened with respect to the game board. A game board production line comprising: a screw tightening control device for performing an operation of fixing an object or the like with screws; and further comprising the following configuration.
(11) The pallet carriage has the following configuration.
(11a) On the upper surface, a plurality of reference columns for horizontally supporting the back surface near the four corners of the game board are installed.
(11b) At least one of the reference struts has a fitting protrusion that fits into an alignment reference hole formed on the back of the game board.
(11c) A large number of support erection hole groups are provided in an area inside the reference support on the upper surface of the pallet carriage.
(11d) Using any of the holes in the support column standing hole group, an internal support column having the same support height as the reference support column is installed so that the position can be changed.
(12) The pallet conveyor has the following configuration.
(12a) A support tool having a support height equal to the back surface height of the game board placed on the pallet carriage is installed in the frame portion of the pallet conveyor near the work position.
(12b) The support is configured by a horizontal rotation member configured to be rotatable about a support column erected on the frame portion as a rotation center.
(21) The automatic screw fastening machine has the following configuration.
(21a) An air cylinder that includes a descending air chamber and an ascending air chamber and that causes the piston rod, to which the driver unit is fixed, to move in a vertical direction, and a cylinder sensor that detects that the air cylinder has started to descend. Be prepared.
(21b) The switching valve for the descending air chamber of the air cylinder is configured to open when negative pressure is generated in the descending air chamber in a state where supply and discharge are stopped, and the driver unit The air cylinder has a weight sufficient to continue to descend even when the lowering air chamber of the air cylinder is stopped to supply and discharge and the ascending air chamber is exhausted.
(22) The screw tightening control device has the following configuration.
(22a) An air supply / discharge switching device that switches the lowering air chamber and the rising air chamber of the air cylinder to any of supply, supply / discharge stop, and exhaust, and a drive device that stops driving the driver unit. Be prepared.
(23) The screw tightening control device executes the following control.
(23a) With respect to the air supply / discharge switching device, after the exhaust side air chamber of the air cylinder is exhausted and the lower side air chamber is supplied, the lower side air chamber is supplied when the cylinder sensor detects the start of lowering. The exhaust stop is performed, and after the screwing is completed, the air supply / discharge operation is performed in which the rising air chamber is supplied and the lower air chamber is exhausted .

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