JPH0781730A - Pallet conveyance device - Google Patents

Abstract

PURPOSE:To simplify a control means and improve conveyance efficiency by operating a stopper by detecting the front edge of a hole section of a pallet and bringing the stopper into contact with the rear edge of the hole section to position the pallet. CONSTITUTION:While a pallet 17 is conveyed to a work site 10A, a front fringe of a hole section 17a of the pallet 17 is detected by a sensor 24A, and a stopper 23A is operated based on the detected signal. A rear fringe of the hole section 17a of the pallet 17 is brought into contact with a contact 231 of the stopper 23A to position the pallet 17 at the work site 10A. As a consequence, it is possible to simplify the constitution of a control means because it is possible to control a stopper at each work site irrespective of presence or absence of a pallet at the other work site.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pallet transporting device for transporting and positioning a pallet to each work place of the assembly line by a free flow conveyor arranged along the assembly line.

[0002]

2. Description of the Related Art As shown in FIG. 13, in a conventional pallet conveyor, a plurality of work sites P are installed on an assembly line.
1, P2, P3, ... are provided, and the work transfer pallet 1 is transferred to the left by a free flow conveyor (not shown) arranged along the assembly line.

Pallet detection sensors S1, S2, S3, ... Provided at work places P1, P2, P3 ,.
Is a pallet 1 to the work places P1, P2, P3, ...
Is turned on just before the end of the loading of the work places P1, P2,
It is turned off when the pallet 1 has been carried out from P3, ....

Therefore, a control unit (not shown) outputs the outputs of the sensors S1, S2, S3, ... And the work places P1, P.
, 2 and 3 are controlled based on the work end signals given from 2, P3 ,.

That is, for example, when a work end signal is given from the work place P1, the stopper 2-1 is lowered. As a result, the pallet 1 is unloaded from the work place P1 and the sensor S1 is turned off. At that time, the stopper 2-1 is raised. Then, when the work end signal is given from the work place P2 while the sensor S1 is outputting the off signal, the stopper 2-2 is lowered.

When the stopper 2-2 descends, the work place P
The pallet 1 is unloaded from the sheet 2 and is conveyed until it comes into contact with the stopper 2-1 at the work place P1. Then, the control unit raises the stopper 2-2 again based on the OFF signal of the sensor S2 generated when the pallet 1 is unloaded from the work place P2.

[0007]

In the conventional conveying apparatus, the stoppers 2-1 and 2-2 are associated with the presence / absence information of the pallet 1 at the work places P1, P2, P3, ....
2, 2, 3, ... Are controlled for the following reason.

That is, for example, when the pallet 1 carried out from the work place P2 reaches the work place P1 while the pallet 1 is located at the work place P1, the pallet 1 is located at the work place P1. Because it abuts
When the work at the work place P1 is completed and the stopper 2-1 is lowered, the pallets 1 move in a state of being connected to each other.

In this case, the succeeding pallet is the work place P1.
Since the sensor S1 does not turn off until after passing through, the subsequent pallet has passed the work place P1 when the stopper 2-1 is raised based on the off signal.

On the other hand, when the pallets 1 are continuously moved as described above, it becomes impossible to bring the stopper into contact with the front edge of the pallet.

In the conventional apparatus, since the above-mentioned control is executed in order to prevent such inconvenience, the structure of the control means becomes complicated. Further, unless the pallet 1 is not present in the work area in the front, the pallet is not carried out from the work area in the rear, so that the cycle time of conveyance becomes long.

In view of the above situation, an object of the present invention is to provide a pallet transfer device which can efficiently transfer pallets using a simple control means.

[0013]

According to the present invention, there is provided a pallet transporting device for transporting and positioning a pallet to each work place on the assembly line by a free-flow conveyor arranged along the assembly line. A hole penetrating the upper and lower surfaces, and a sensor that is disposed in the passage area of the hole of the pallet in each of the work places, and detects the front edge of the hole while the pallet is being carried into the work place. A stopper arranged in the passage area of the hole portion of the pallet in each of the work locations, which contacts the trailing edge of the hole portion of the pallet carried into the work location to position the pallet, and the sensor includes the pallet. When the front edge of the hole is detected, stopper control means for activating the stopper at the corresponding work place is provided.

[0014]

The sensor provided at each work place detects the front edge of the hole portion of the pallet while the pallet is being carried into the work place. Then, the stopper is actuated based on the detection signal of the sensor, and the stopper comes into contact with the trailing edge of the hole portion of the pallet that has finished loading the pallet to the work place.

[0015]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows the configuration of a work station 10 in an assembly line for an engine or the like.

In FIG. 1, the conveyor rails 11 and 12 are arranged along the assembly line of the guide rails 11 and 12 as shown in FIG. Rollers 13 and 14 are arranged on the upper surface at predetermined intervals.

The group of rollers 13 on the conveyor rail 11 and the group of rollers 14 on the conveyor rail 12 are connected to a chain (not shown). Therefore, as the chain moves, the rollers 13 and 14 group on the conveyor rails 11 and 12. Move while rolling.

The rails 11 and 12, the rollers 13 and 1
The fourth group and the chain are the conveyor rails 11 and 12
Pallet guides 15, which are installed adjacent to each other outside the
Together with 16, a so-called free flow conveyor is configured.

The pallet 17 has a rectangular hole 17a penetrating the upper and lower surfaces of the pallet 17 at the center thereof. The pallet 17 is placed on the rollers 13 and 14 in such a manner that one side surface and the other side surface of the pallet 17 are in contact with the pallet guides 15 and 16, respectively. Transported to the left.

In the work place 10A shown in FIG. 1, a seat plate 18 is provided.
And a pair of seat plates 19 are arranged. The tip of each seat plate 18 on the rail 11 side faces each corner of one end of the pallet 17 located at the work place 10A, and the tip of each seat plate 19 on the rail 12 side is The pallet 17 faces each corner of the other end.

Lifters 20 and 20 'are provided inside the conveyor rails 11 and 12 in the work place 10A, respectively. As shown in FIG. 3, which is a sectional view taken along line BB of FIG. 1, the lifter 20 includes a flat plate-shaped bracket 201 and guide rods 202 and 203 projecting from left and right end portions of the bracket 201, respectively.
And guide cylinders 204 and 205 in which these guide rods 202 and 203 are slidably fitted, and an air cylinder 206 for raising and lowering the bracket 20. The other lifter 20 'also has a structure similar to that of the lifter 20.

The work place 10A is provided with a stopper 23A and a pair of sensors 24A and 25A, and the waiting place 10 is provided adjacent to the work place 10A on the right side thereof.
B has a corresponding stopper 23B and sensor 24B,
25B is provided.

As shown in FIG. 4, which is a sectional view taken along line CC of FIG. 1, the stopper 23A is provided with a contact 231 and an air cylinder 232 for moving the contact 231 up and down. Hole 1 of pallet 17 positioned
The position is set so that the contactor 231 can be brought into contact with the rear edge of the 7a.

The contact 231 is used for the bracket 2
Piston rod 23 of air cylinder 232 via 33
It is attached to 2a and can be tilted in the clockwise direction as shown by the broken line in FIG.

The stopper 23B at the waiting place 10B has the same structure as the stopper 23A. The position of the stopper 23B is set so that the contactor 231 contacts the rear edge of the hole 17a of the pallet 17 located at the standby place 10B.

The sensor 2 provided in the work place 10A
4A and 25A are juxtaposed on a line orthogonal to the conveyor rails 11 and 12. Then, the sensor 24A is configured to move the pallet 17 during movement of the pallet 17 at the work place 10A.
Hole portion 17a of the work place 10A
In the illustrated state in which the loading of the pallet 17 into the pallet 17 is completed, the position is set so that the upper end of the pallet 1 is covered by the rear end of the pallet 1. Also, the sensor 25A
Is set such that the lateral side end of the pallet 17 where the hole 17a does not exist passes above it. The arrangement positions of the sensors 24B and 25B are set so that the same conditions as above are satisfied in the standby place 10B.

The above-mentioned sensors 24A, 25A, 24
B and 25B are turned on by, for example, optically detecting the lower surface of the pallet 17 when the lower surface exists above them.

As shown in FIG. 6, the anti-back mechanism 26 provided at the boundary position between the working place 10A and the waiting place 10B has an anti-back piece 262 whose base is pivotally attached to a support 261 and a support 261. It includes a piston member 263 that is slidably fitted and a spring 264 that biases the piston member 263 upward.

The anti-back piece 262 is pushed up to the position shown by the urging force of the piston member 263 acting on the lower side of the anti-back piece 262.
The pin 265 provided on the support 261 is in contact with the upper inner peripheral surface of the hole 266 provided on the support 261. The anti-backpiece 262 can be locked by bringing the tip of the lock screw 267 into contact with the rear surface of the anti-backpiece 262. The posture is maintained.

7 to 10 show the manner in which the pallet 17 is conveyed, and FIG. 11 shows the sensors 24A, 25A and 2 respectively.
The lifters 20, 2 based on the outputs of 4B and 25B
0'air cylinder 206 and the stoppers 23A, 23
FIG. 12 shows an example of the configuration of the control unit 100 that controls the B air cylinder 232, and FIG. 12 shows a timing chart of the control unit 100.

The operation of this embodiment will be described below with reference to these figures. As shown in FIG. 7 (A),
The pallet 17 is conveyed to the work place 10A and the standby place 10B by the conveyor. Then, the pallet 17 has the sensors 24B, 2 of the standby place 10B.
If the vehicle passes over 5B and reaches the position shown in FIG. 7B, the sensors 24B and 25B output the signals shown in FIGS. 12G and 12H, respectively, during the passage.

In the AND circuit 111 shown in FIG. 11, the sensor 24B, the sensor 25B, and the sensor 25A are off,
The logic level of its output becomes "H" under the condition of ON and ON, but the above condition is not satisfied until the pallet advances to the position shown in FIG. Stopper 23B at location 10B
Holds the inactive state.

In the state shown in FIG. 7B, the pallet 1
The front end of 7 is positioned above the sensors 24A and 25A, and both sensors are turned on as shown in FIGS. 12 (a) and 12 (b) (at time t1 in FIG. 12). And pallet 1
7 further progresses, and as shown in FIG.
When the hole 17a of the pallet 17 is located above 4A, the sensor 24A is turned off and the sensor 25A is turned on (at time t2 in FIG. 12).
The logic level of the output of 01 changes to "H". Therefore,
The trigger circuit 102 outputs the trigger signal shown in FIG. 12C to set the flip-flop 103.

The set flip-flop 103
Output of the electromagnetic valve 1 via the valve drive circuit 104.
No. 05 is switched and operated, the air supplied from the pressurized air source 200 is supplied to the air cylinder 2 of the stopper 23A.
32 expands.

As a result, the contact 231 of the stopper 23A
Starts rising from the descent position shown by the chain line in FIG. However, in the state of FIG. 7C, since the front end portion of the pallet 17 is located above the contactor 231, the contactor 231 contacts the lower surface of the front end of the pallet during the ascending operation and moves clockwise. Tilt. Then, when the hole 17a of the pallet 17 is located above it, the tentacle 231 is returned to the position shown by the solid line in FIG. 5 by a return spring (not shown), and its upper part is inside the hole 17a. Get in.

Thereafter, the pallet 17 is further moved leftward, and eventually, as shown in FIG. 8A, the sensor 24A detects the rear end of the pallet 17 and turns on (at time t3 in FIG. 12). At this time, as shown in FIG. 5, the trailing edge of the hole 17a of the pallet 17 contacts the contactor 231 of the stopper 23A, so that the pallet 17 is forcibly stopped, and as a result, the pallet 17 is placed at the work place 10A. Positioned.

Before the pallet 17 reaches the position shown in FIG. 8A, the front end and the rear end of the pallet 17 are located at the boundary between the working place 10A and the waiting place 10B. As it passes over the back mechanism 26, the lower surfaces of their ends push down the anti-backpiece 262 shown in FIG. 6 against the spring 264. Therefore, the anti-backpiece 262 does not hinder the progress of the pallet 17.

Then, the anti-back piece 262 returns to the position shown by the solid line in FIG. 6 when the pallet 17 is conveyed to the position shown in FIG.
It is locked to the end face of the notch 17b provided at the center of the rear edge. Therefore, the pallet 17 is prevented from moving to the right by the anti-backpiece 262.

In the state of FIG. 8A, the sensor 25A is still in the ON state and the flip-flop 103
Hold the set state, the logic level of the output of the AND circuit 106 shown in FIG. 11 becomes "H" with the ON operation of the sensor 24A.

As a result, the trigger circuit 107 to FIG.
The trigger signal shown in (e) is output, and the flip-flop 108 is set as shown in FIG. Then, the output of the set flip-flop 108 switches the electromagnetic valve 110 through the valve drive circuit 109 to operate, so that the air cylinders 206 of the lifters 20 and 20 'are supplied from the pressurized air source 200. The extension operation is performed simultaneously by the air.

When the brackets 201 (see FIG. 3) of the lifters 20 and 20 'are raised by the extension operation of the air cylinder 206, first, a projection 207 protruding from the upper surface of the bracket 201 is formed in the pallet 17 as shown in the drawing. The pallet 17 is raised until it comes into contact with the seating plates 18 and 19 shown in FIGS. As a result, palette 17
Is locked at the work place 10A with its lower surface floating above the rollers 13, 14 (see FIG. 2).

On the other hand, the trigger signal output from the trigger circuit 107 is supplied as a work start instruction signal to the control means (not shown) of the assembly processing machine 30 shown in FIGS. Predetermined assembly processing is performed on a work (not shown) on the locked pallet 17.

When the assembling work for the work is completed, a work end signal is generated by the control means or the operator (at time t7 in FIG. 12). This signal is input as a reset signal to the flip-flops 103, 108 and a flip-flop 113 described later, so that both flip-flops 103, 108 are reset as shown in FIGS. 12 (d) and 12 (f). To be done.

As a result, the valves 105 and 110 are switched, and the stopper 23A and the lifters 20 and 2 are operated.
0'is moved downward, and the pallet 17 which has been located at the work place 10A until now is discharged to the left, that is, toward the next work station.

The pallet 17 is moved slightly leftward from the position shown in FIG. 8 (A), and its rear ends are sensors 24A, 25.
When passing above A, the time point (time point t8 in FIG. 12)
Both sensors will turn off.

Next, a case will be described in which the subsequent pallet 17 is carried into the waiting place 10B while the assembling work is being performed at the working place 10A.

As shown in FIG. 8 (B), when the leading end of the subsequent pallet 17 is positioned on the sensors 24B, 25B, the sensors 24B, 25 (j) as shown in FIGS.
Both 25B are turned on at that time (time t4). Then, as shown in FIG. 8C, when the pallet 17 advances and the hole portion 17a of the pallet is positioned on the sensor 24B,
At that time (time t5), the sensor 24B is turned off.

When the sensor 24B is off, the other sensor 25B remains on, and the sensor 25A at the work place 10A is on. Therefore, the logic level of the output of the AND circuit 111 shown in FIG. 11 changes to “H”, and as a result, the trigger circuit 112 outputs the trigger signal shown in FIG. 12 (k) to set the flip-flop 113.

Flip-flop 113 set above
Output of the electromagnetic valve 1 via the valve drive circuit 114.
15 is switched and operated. As a result, the pressurized air source 200
Since the air cylinder 232 (see FIG. 5) of the stopper 23B is extended by the air supplied from the hole 23 of the pallet 17, the air cylinder 232 of the stopper 23B is extended above the contactor 231 of the stopper 23B.
At the time when 7a is positioned, the upper end of the contactor 231 enters into the hole 17a.

Then, as shown in FIG. 9 (A), when the pallet 17 is further moved to the left and the carrying in of the pallet 17 to the waiting place 10B is completed, the hole 17a of the pallet 17 is completed.
The trailing edge comes into contact with the contactor 231, and the standby position 10B
The pallet 17 is positioned at.

Thus, according to this embodiment, the succeeding pallet 17 is stopped at the waiting place 10B, so that the succeeding pallet 17 can be prevented from colliding with the pallet 17 at the working place 10A.

After the completion of the positioning of the pallet 17 at the waiting place 10B or before the completion of the positioning, the work place 1
When the work end signal is output at the time t9 in FIG. 12 after the work of 0A is completed, this signal is output to the flip-flops 103 and 108 and the flip-flop 11 described above.
3 as a reset signal.

When the flip-flops 103, 108 and 113 are reset by the reset signal, the contactor 231 of the stoppers 23A and 23B descends.
While the pallet 17 of the work place 10A is unloaded,
The pallet 17 in the waiting place 10B moves to the working place 10A side.

Next, the operation when the pallets 17 are conveyed adjacent to each other, as shown in FIG. 9B, will be described. In this case, as shown in FIG. 12 (m), from the time when the rear end of the preceding pallet 17 is positioned on the sensor 24B (time t0 in FIG. 12), the succeeding pallet 17 is changed to the state shown in FIG. ), That is, the pallet 17
At the time when the hole 17a is located on the sensor 24B (see FIG.
The sensor 24B continues to be in the ON state until the time t2 'of 2).

When the sensor 24B is turned off,
At the time 2 ′, the other sensor 25B is kept in the ON state, and the sensor 25A at the work place 10A is in the ON state. Therefore, the logical level of the output of the AND circuit 111 shown in FIG. 11 changes to “H”, and as a result, the trigger circuit 112 outputs the trigger signal shown in FIG. 12 (o) to set the flip-flop 113.

Flip-flop 113 set above
The output of the above operates the stopper 23B as described above. Therefore, when the succeeding pallet 17 advances to the position shown in FIG. 10 (A), the contact 231 of the stopper 23B comes into contact with the trailing edge of the hole 17a of the succeeding pallet 17, resulting in a waiting place. The pallet 17 is positioned on 10B.

At this time, the stopper 23 of the work place 10A
A has already been actuated at time t2 in FIG. 12, so that the preceding pallet 17 moves to the stopper 23A at the time when it moves a short distance from the position in FIG. 10 (A), as shown in FIG. 10 (B). It abuts and is positioned at the work place 10A. At the time of positioning the preceding pallet 17 (time t3 in FIG. 12), as described above, the flip-flop 103 is set and the lifters 20 and 20 'are lifted.

When the work for the work on the pallet 17 at the work place 10A is completed, the work completion signal described above is generated and all the flip-flops 103, 108 and 113 currently in the set state are reset. The pallet 17 in the work place 10A is unloaded, and the pallet 17 in the standby place 10B is carried in and positioned on the work place 10A side.

Further, as shown by a chain double-dashed line in FIG. 10B, when the next pallet 17 is adjacent to the pallet 17 located at the waiting place 10B, the pallet at the waiting place 10B is adjacent to the pallet 17. As the 17 moves to the work place 10A side, the adjacent pallet 17 is moved to the waiting place 10B.
Be delivered to.

By the way, the work place 10A, the waiting place 10B, and the respective elements provided at these places are also provided at other work stations (not shown) in the assembly line.

The lifter 20 at each work station,
The control of 20 'and the stoppers 23A and 23B is executed independently in each work station, that is, irrespective of the presence or absence of a pallet in another work station and the working state, as is clear from the above description of the operation. It
Therefore, according to the present invention, the above control becomes extremely easy, and the cycle time of conveyance is shortened as much as possible.

The intervals between the above work stations are as follows.
The size is set so that a plurality of pallets 17 can be arranged between these stations, and normally, the pallets can be sent between the respective work stations.
However, it is expected that the pallet 17 will be filled between the work station and the work station behind the work station due to a failure of the assembly machine of the work station.

Therefore, in this embodiment, an appropriate sensor (not shown) for detecting the occurrence of the above situation is provided between the respective work stations, and when the sensor detects the occurrence of the above situation, the corresponding station. Palette 1 between
7 is prohibited to carry out.

In the above-described embodiment, the pallet 17 positioned at the work place 10A is lifted from the conveyor by the lifters 20 and 20 'to reduce the burden on the conveyor during work, and the subsequent pallet 17 is placed at the waiting place 10B. Therefore, the pallet 17 at the work place 10A and the subsequent pallet 17 are prevented from interfering with each other.

However, when the rigidity and driving force of the conveyor are high, the pallet 17 is clamped in a state where it does not float above the conveyor, and the subsequent pallet 17 is brought into contact with the preceding pallet 17 at the work place 10A and stopped. Is also possible. And in this case, the lifter 2
0, 20 ', the waiting place 10B, the stopper 23B and the sensors 24B, 25B are unnecessary.

Further, in the above embodiment, the stoppers 23A, 23B, etc. are controlled by the control unit 100 shown in FIG. 11, but the operation of the logic elements of the control unit 100 is controlled by the CPU.
It is also possible to obtain using a microprocessor such as.

[0067]

According to the present invention, the stopper of each work place can be controlled regardless of the presence or absence of a pallet at another work place, so that the structure of the control means can be simplified. Further, even when the pallet 1 is present in the work area in the front, the pallet can be carried out from the work area in the rear, so that the cycle time of the transfer can be shortened and the transfer efficiency can be improved. .

[Brief description of drawings]

FIG. 1 is a plan view showing an embodiment of the present invention.

FIG. 2 is an enlarged side view of the embodiment.

FIG. 3 is a sectional view taken along line BB of FIG.

FIG. 4 is a cross-sectional view taken along the line CC of FIG.

FIG. 5 is a conceptual diagram showing the structure and operation of a stopper.

FIG. 6 is a sectional view showing a configuration of an anti-back mechanism.

FIG. 7 is a conceptual diagram showing a transportation mode of pallets.

FIG. 8 is a conceptual diagram showing a transportation mode of pallets.

FIG. 9 is a conceptual diagram showing a transportation mode of pallets.

FIG. 10 is a conceptual diagram showing a transportation mode of pallets.

FIG. 11 is a block diagram showing a configuration example of a control unit.

FIG. 12 is a timing chart showing the operation of the control unit.

FIG. 13 is a conceptual diagram showing a pallet transport mode in a conventional pallet transport device.

[Explanation of symbols]

 10 work station 10A work place 10B standby place 11,12 conveyor rail 13,14 roller 17 pallet 17a hole 20,20 'lifter 23A, 23B stopper 24A, 24B, 25A, 25B sensor 100 control unit 101,106,111 AND circuit 102, 107, 112 Trigger circuit 103, 108, 113 Flip-flop

Claims (1)

[Claims] 1. A pallet transporting device for transporting and positioning a pallet to each work place on the assembly line by a free-flow conveyor arranged along the assembly line, the hole portion penetrating the upper and lower surfaces of the pallet. A sensor disposed in the passage area of the hole portion of the pallet in each of the work places, for detecting the leading edge of the hole portion during the loading of the pallet to the work place, and the pallet of the pallet in each work place. A stopper which is arranged in the passage area of the hole and contacts the rear edge of the hole of the pallet carried into the work place to position the pallet, and the sensor detects the front edge of the hole of the pallet. A pallet transporting device, comprising: stopper control means for activating the stopper at the corresponding work place at the point of time.