Erroneous delivery prevention device and method for cart

Abstract

To prevent a cart 1 loaded with a component 2 from being delivered to an erroneous cart carry-in position 5 on a line side.SOLUTION: A lock mechanism 7 that collides with wheels of the cart 1 to prevent the cart 1 from entering, when locked, is provided at each of the plurality of cart carry-in positions 5. When a transport operator scans an identification code 3 attached to the component 2 with a portable identification code reader 9, a controller 11 identifies the cart carry-in position 5 corresponding to the identification code 3 and unlocks the lock mechanism 7. At the same time, a spotlight 13 and an LED light 26 at the cart carry-in position 5 flash, so that an erroneous delivery is reliably prevented.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a device and method for preventing erroneous removal of a cart, which prevents an operator from placing a cart for transporting parts on an assembly line in a factory, in an incorrect cart carry-in position other than the appropriate cart carry-in position. [Background technology]

[0002] For example, in an automobile assembly line, a relatively large part may be transported to a supply entrance on the side of the line while still mounted on a cart. Patent Document 1 discloses a so-called push cart that is moved manually by a worker. With such a push cart, the worker moves the cart to a predetermined cart entry position (i.e., the supply entrance) on the side of the line corresponding to the part while checking a mark or the like on the floor, thereby performing so-called removal of the cart. Note that "removal" refers to the transportation of parts, pallets, or carts to a location on a production line or the like where part supply is required, and here particularly refers to moving the cart to a predetermined cart entry position and placing it at the cart entry position. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2020-6781 A Summary of the Invention [Problem to be solved by the invention]

[0004] In this manner, in which the worker moves the cart to the cart carry-in position corresponding to the part, the worker may make a careless mistake and the cart may be delivered to the wrong cart carry-in position. [Means for solving the problem]

[0005] The device for preventing erroneous dispensing of a cart according to the present invention comprises: A cart for transporting a part having an identification code; a locking mechanism that is provided at each of the plurality of trolley loading positions and that prevents the trolley from entering in a locked state and allows the trolley to enter in an unlocked state; An identification code reader; a controller that identifies a corresponding carriage loading position based on the identification code read by the identification code reader and unlocks a locking mechanism at the carriage loading position; It is equipped with:

[0006] In this way, the locking mechanism of the cart carry-in position corresponding to the identification code of the part being transported by the cart is unlocked, so that the worker can move the cart to this cart carry-in position. If the worker attempts to move the cart to the wrong cart carry-in position, the locking mechanism physically prevents the cart from entering the cart carry-in position. Effect of the Invention

[0007] According to this invention, even if a worker mistakenly attempts to push a trolley into a trolley input position that does not correspond to the part's identification code, the locking mechanism physically prevents the trolley from entering, thereby reliably preventing the trolley from being pushed out erroneously due to a careless mistake, etc. [Brief description of the drawings]

[0008] [Figure 1] FIG. 2 is an explanatory diagram showing a system configuration of an embodiment of a device for preventing erroneous dispensing of a cart. [Diagram 2] FIG. 4 is a plan view of the locking mechanism according to the embodiment; [Diagram 3] FIG. 4 is a side view of the locking mechanism of the embodiment. [Figure 4] FIG. [Diagram 5] FIG. 13 is a plan view showing the position of the locking mechanism within the compartment where the cart is loaded. [Figure 6] 11 is a flowchart showing the processing flow of the erroneous dispensing prevention device according to one embodiment. [Figure 7] 11 is a flowchart showing the flow of processing when removing an empty cart. [Figure 8]11 is an explanatory diagram showing the operation of the locking mechanism when the cart is brought in and removed. FIG. [Figure 9] FIG. 11 is a plan view of a locking mechanism according to a second embodiment. [Figure 10] FIG. 13 is a front view of the locking mechanism according to the second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] An embodiment of the present invention will be described in detail below with reference to the drawings. Fig. 1 is a configuration explanatory diagram showing the system configuration of an erroneous delivery prevention device of an embodiment applied to parts conveyance in an automobile assembly line L (for example, an outfitting line).

[0010] In an automobile assembly line L, workers (assembly workers) assemble various parts onto the vehicle bodies that move along the assembly line L. If the parts to be assembled are relatively small, they are supplied sequentially, for example on box-shaped containers or pallets, to a storage area for each part called a supply entrance that is provided on the side of the line, and the assembly workers pick up the parts from here and assemble them into the vehicle bodies.

[0011] On the other hand, when the parts are relatively large, for example, insulators or undercovers that are longer than 1m, the parts are supplied by leaving the parts loaded on the dolly that transports the parts at the dolly entrance position, which is a specified supply opening. In this case, the assembly worker takes the parts directly from the dolly and assembles them on the vehicle body. When all the parts loaded on the dolly are gone, an empty dolly is pulled out from the dolly entrance position, which is the supply opening, and the next dolly is parked in its place. This embodiment is a technology applied to parts transportation using such dollies.

[0012] As shown diagrammatically in FIG. 1, parts 2 are mounted or loaded on a cart 1, and each part 2 or a pallet on which the parts 2 are loaded is affixed with an identification code 3 such as a barcode or a QR code (registered trademark). The cart 1 is a hand-pushed type that can be moved manually by a worker (transport worker). Although only one cart 1 is shown in FIG. 1, multiple carts 1 are connected together and transported near the assembly line L by being pulled by a powered vehicle. Then, after being detached from the powered vehicle near the assembly line L, the worker moves the cart manually.

[0013] A plurality of carriage entrance positions 5 serving as supply entrances are provided in a line for the carriage 1 along the assembly line L. Each carriage entrance position 5 has a rectangular section slightly larger than the outer shape of the carriage 1, and is indicated, for example, by painting boundary lines on the factory floor. Each carriage entrance position 5 is also assigned a number or code for identification.

[0014] The erroneous dispensing prevention device of one embodiment includes a locking mechanism 7 provided at each of a plurality of trolley loading positions 5, an identification code reader 9 (e.g., a barcode reader or a QR code (registered trademark) reader) that reads an identification code 3 attached to a part 2 transported by a trolley 1, and a controller 11 that identifies a corresponding trolley loading position 5 based on the read identification code 3 and unlocks the locking mechanism 7 at the trolley loading position 5. In addition, as part of the erroneous dispensing prevention device, a spotlight 13 (corresponding to a second indicator light) made of, for example, an LED is provided above each trolley loading position 5 to indicate an unlocked trolley loading position 5.

[0015] The lock mechanism 7 will be described in detail later, but in the locked state, it is configured to physically interfere with the wheels 1a (front wheels) of the dolly 1 to prevent the dolly 1 from entering. In one embodiment, the identification code reader 9 is a portable code reader that is always carried by the transport worker, and this identification code reader 9 is connected to the controller 11 via short-range wireless communication 12 (e.g., Bluetooth (registered trademark)) with the communication unit 11a of the controller 11. The controller 11 identifies the dolly carry-in position 5 corresponding to the identification code 3 sent from the identification code reader 9, and unlocks the lock mechanism 7 as described later. At the same time, a spotlight 13 provided above the corresponding dolly carry-in position 5 flashes, for example, in blue. This allows the transport worker to put out the dolly 1 into the section of the predetermined dolly carry-in position 5 that is unlocked. Even if the transport worker mistakenly tries to put the cart 1 into another cart carry-in position 5, the lock mechanism 7 prevents the cart 1 from being retained in the cart carry-in position 5. Therefore, erroneous removal of the cart is reliably prevented.

[0016] Next, the lock mechanism 7 of one embodiment will be described with reference to Figures 2 to 4. Figure 2 is a plan view of the lock mechanism 7, and Figure 3 is a side view of the lock mechanism 7. The lock mechanism 7 of the illustrated example is configured with a substantially rectangular base plate 21 fixed to the floor surface of a factory, a footplate 23 supported rotatably about a rotation shaft 22 extending parallel to the base plate 21, an electromagnetic latch mechanism 24 that prevents the footplate 23 from rotating in one direction, a photoelectric switch 25 that detects when the footplate 23 is in the unlocked position, and a tape-shaped LED light 26 that serves as an indicator lamp that displays the state of the lock mechanism 7.

[0017] 2, arrow D indicates the direction of entry when the cart 1 is brought in, and the wheels (front wheels) 1a of the cart 1 move across the footboard 23. The rotating shaft 22 is supported at both ends by bearings 27, 28 on the base plate 21, and is positioned so as to be perpendicular to the entry direction D.

[0018] The step 23 made of a steel plate has a front portion 23A on the front side in the approach direction D (the rear side in the compartment of the cart carry-in position 5) and a rear portion 23B on the rear side in the approach direction D (the entrance side in the compartment of the cart carry-in position 5) with the rotation shaft 22 in between, and as shown in Fig. 3, the front portion 23A and the rear portion 23B are bent to each other so as to form an obtuse angle. In one embodiment, the front portion 23A and the rear portion 23B form an angle of 120°, but the appropriate angle differs depending on the size of the wheel 1a, etc., and is not limited to 120°.

[0019] 3 shows the position of the footboard 23 in the locked state, in which the rear portion 23B is positioned along the upper surface of the base plate 21, and the front portion 23A is positioned rising from the upper surface of the base plate 21. With the front portion 23A rising in this way, in the locked state, the movement of the wheel 1a approaching along the approach direction D is prevented.

[0020] In the unlocked state, that is, in the state where the step 23 can freely rotate around the rotation axis 22, the wheel 1a of the cart 1 passes over the step 23, causing the step 23 to rotate. For example, when the wheel 1a moves along the approach direction D, the wheel 1a presses the raised front part 23A, causing the step 23 to rotate forward, and the wheel 1a can pass over the step 23. When the step 23 rotates as the wheel 1a passes over it in this way, the front part 23A is positioned along the upper surface of the base plate 21, and the rear part 23B is raised. In this state, when the wheel 1a moves in the opposite direction to the approach direction D (the pull-out direction), the wheel 1a presses the raised rear part 23B, causing the step 23 to rotate in the opposite direction. This allows the wheel 1a to pass over the step 23 in the pull-out direction. In one example where the rear portion 23B and the front portion 23A form an angle of 120°, the foot plate 23 can rotate about 60° in both the clockwise and counterclockwise directions in FIG.

[0021] The electromagnetic latch mechanism 24 is located opposite one side edge of the rear portion 23B. The electromagnetic latch mechanism 24 has a latch bolt 31 that is constantly biased in a protruding direction by a spring against a case 30, and this latch bolt 31 engages with the upper surface of the side edge of the rear portion 23B as shown in Fig. 3. This prevents the foot plate 23 from rotating in the clockwise direction in Fig. 3, and therefore the lock mechanism 7 is in a locked state.

[0022] 4 shows the electromagnetic latch mechanism 24 alone, with a rectangular column-shaped latch bolt 31 protruding from the end face of the case 30. The latch bolt 31 is biased in the protruding direction by a spring, but the latch bolt 31 retracts when electricity is applied to the solenoid of the electromagnetic latch mechanism 24 as a release signal. Therefore, while the solenoid is energized, the mechanism is in an unlocked state, allowing the foot plate 23 to rotate in the clockwise direction in FIG. 3.

[0023] In addition, the upper surface of the tip portion of the latch bolt 31 protruding from the case 30 forms a tapered surface 31a of about 45°. This allows the footboard 23 to rotate in the counterclockwise direction in FIG. 3 even when the solenoid is not energized. In other words, when the wheel 1a passes over the footboard 23 in the pull-out direction, the upright rear portion 23B moves in the counterclockwise direction in FIG. 3 and contacts the tapered surface 31a of the latch bolt 31. The component force generated according to the angle of the tapered surface 31a causes the latch bolt 31 to move back against the spring force, and the rear portion 23B can enter the lower side of the latch bolt 31 (i.e., the lock position). Therefore, the movement of the wheel 1a in the pull-out direction is always permitted without the need for energizing the solenoid. Note that a cushioning material may be attached to one or both of the tapered surface 31a and the corresponding portion of the rear portion 23B that contact each other to prevent abnormal noise.

[0024] 2, photoelectric switch 25 is disposed so as to face the side edge of front portion 23A, and detects front portion 23A and outputs an ON signal when front portion 23A is in a position along the upper surface of base plate 21. In other words, it detects that footboard 23 has rotated to the unlocked position. Tape-shaped LED light 26 is disposed on one of bearing portions 27, and is capable of emitting a plurality of colors (e.g., blue, purple, red).

[0025] In addition, the locking mechanism 7 of the embodiment shown in Figures 2 and 3 is provided with a gently sloping entrance side inclined plate 33 and an exit side inclined plate 34 on both the front and rear sides of the base plate 21 in order to reduce the step between the floor surface and the footboard 23.

[0026] 5 is a plan view showing the position of the locking mechanism 7 (in other words, the base plate 21) in the compartment of each cart loading position 5. As shown in the figure, in a preferred embodiment, the locking mechanism 7 is located toward the front of the compartment of the cart loading position 5 in correspondence with one of the wheels (e.g., the right wheel) at the front in the approach direction D. By arranging the locking mechanism 7 toward the front of each compartment in this way, it is less likely to get in the way of a work vehicle walking on the floor surface. In addition, when the cart 1 is pushed out into the compartment, the wheels are less likely to go around the locking mechanism 7.

[0027] Spotlights 13 provided above each section are positioned so as to illuminate the area around the locking mechanism 7.

[0028] Fig. 6 is a flowchart showing the process flow of the erroneous dispensing prevention device of one embodiment, and below, with reference to Fig. 6, the operation of the controller 11, the locking mechanism 7, etc. when dispensing the cart 1 to the corresponding cart loading position 5 will be described. Note that the flowchart in Fig. 6 includes manual processes performed by the transport operator as well as processes performed by the controller 11.

[0029] First, in step 1, after the cart 1 is separated from the power vehicle near the assembly line L, a transport worker scans the identification codes 3 of the parts 2 loaded on the cart 1 with an identification code reader 9. In the case of Bluetooth (registered trademark), the identification code reader 9 is paired with the communication unit 11a of the controller 11 before scanning.

[0030] In step 2, the controller 11 searches for a supply entrance, i.e., a trolley delivery position 5, corresponding to the loaded part 2, based on the identification code 3 transmitted from the identification code reader 9. Then, in step 3, it is determined whether or not there is a trolley delivery position 5 corresponding to the part 2 (hereinafter, this will be referred to as the "target delivery position"). If NO, the process ends. This determination is made within an area of ​​about several tens of meters. If there is a target delivery position, the current state of the target delivery position (locked state, presence or absence of a trolley 1, etc.) is confirmed (detection signal is obtained) (step 4), and it is determined whether the photoelectric switch 25 is off (step 5). The photoelectric switch 25 being off means that there is no trolley 1 at the target delivery position, and the footboard 23 is in the locked position.

[0031] If the photoelectric switch 25 is off, the process proceeds to step 6, where the electromagnetic latch mechanism 24 is unlocked (solenoid on) and a 40-second timer is started. The solenoid is energized for 40 seconds. At the same time, the LED light 26 of the lock mechanism 7 and the spotlight 13 are made to flash blue.

[0032] The transport worker can know the target delivery position by following this flashing blue light, and in step 7, pushes the cart 1 into the target delivery position (i.e., pushes it out). At this time, the right front wheel 1a of the cart 1 passes over the footboard 23 of the locking mechanism 7. Because the electromagnetic latch mechanism 24 is unlocked, the footboard 23 rotates as the cart 1 moves in.

[0033] The controller 11 again checks the state of the target loading position (step 8) and determines whether the photoelectric switch 25 is on or not (step 9). If the cart 1 has been properly loaded into the target loading position and the footboard 23 has rotated, the photoelectric switch 25 is turned on. If the photoelectric switch 25 is on, the process proceeds to step 10, where the LED light 26 of the locking mechanism 7 and the spotlight 13 are turned off. At the same time, an appropriate completion sound is output from the speaker.

[0034] If the photoelectric switch 25 is not turned on during the 40 seconds that the solenoid is energized (NO in step 9), the controller 11 ends the timer (step 11), stops the energization of the solenoid of the electromagnetic latch mechanism 24, and puts the locking mechanism 7 in the locked state again. At the same time, the LED light 26 and the spotlight 13 of the locking mechanism 7 are turned off (step 12). This means that for some reason the cart 1 was not dispensed during the preset time of 40 seconds.

[0035] If the answer is NO in step 5, that is, if the photoelectric switch 25 at the target carry-in position is on (this includes both cases where a cart 1 is present or not present at the target carry-in position), the controller 11 outputs an error and blinks the LED light 26 in red in step 13. The transport worker presses a reset switch provided at an appropriate position around the cart carry-in position 5, thereby notifying the manager that there is an abnormality.

[0036] In this manner, in the above embodiment, the transport worker scans the identification code 3 of the part 2, and the target carry-in position to which the trolley 1 should be removed, in other words the target carry-in position from which the locking mechanism 7 has been released, is displayed by the LED light 26 and the spotlight 13 flashing blue. This allows the transport worker to deliver the trolley 1 to the target carry-in position without making a mistake. Even if the transport worker mistakenly attempts to insert the trolley 1 into another trolley carry-in position 5 (for example, the adjacent trolley carry-in position 5), the locking mechanism 7 is physically blocked by the locked state, so erroneous removal will not occur.

[0037] Next, Fig. 7 is a flow chart showing the process flow when removing an empty trolley. As shown in step 21, the trolley 1, which is empty after all the loaded parts 2 have been used, is manually removed from the trolley carry-in position 5 by the transport worker. The trolley is then coupled to a powered vehicle and returned to the dump site where parts are loaded. When removing the trolley 1, as described above, the footboard 23 of the locking mechanism 7 can freely rotate counterclockwise in Fig. 3, so there is no need to energize the solenoid of the electromagnetic latch mechanism 24. In other words, the transport worker can take the empty trolley 1 out of the compartment of the trolley carry-in position 5 at any time, which improves workability.

[0038] The controller 11 checks the state of the target loading position (step 22) and determines whether the photoelectric switch 25 is off (step 23). If it is not off, it waits until an empty cart is pulled out and the photoelectric switch 25 is turned off. When the photoelectric switch 25 is turned off, the process proceeds to step 24, where the LED light 26 of the locking mechanism 7 is illuminated in purple and the spotlight 13 is illuminated in blue. Note that the solenoid of the electromagnetic latch mechanism 24 remains de-energized, and the footplate 23 of the locking mechanism 7 rotates counterclockwise in FIG. 3, causing the locking mechanism 7 to enter the locked state.

[0039] When the cart 1 is not present in the compartment of the cart loading position 5, the LED light 26 of the locking mechanism 7 is on, so that the worker is less likely to trip over it by mistake.

[0040] 8 is an explanatory diagram showing a schematic diagram of the lock mechanism 7, particularly the operation of the step plate 23, associated with the delivery (removal) of the cart 1 to the target delivery position and the removal of the cart 1. FIG. 8(a) shows the state in which the wheels 1a of the cart 1, which has been pushed along the approach direction D, come into contact with the step plate 23. If the target delivery position is not corresponding to the part 2, the step plate 23 does not rotate, and the entry of the cart 1 is prevented. If the target delivery position is corresponding to the part 2, the step plate 23 rotates as pushed by the wheels 1a as shown in FIG. 8(b), allowing the cart 1 to enter. After that, when the cart 1 becomes empty and is to be removed, the step plate 23 rotates as pushed by the wheels 1a as shown in FIG. 8(c), allowing the cart 1 to be removed.

[0041] Although one embodiment of the present invention has been described above in detail, the present invention is not limited to the above embodiment and various modifications are possible. For example, in the above embodiment, an example in which the present invention is applied to a cart in an automobile outfitting line has been described, but the present invention can also be applied to carts for other purposes. In addition, the identification code reader 9 may be a fixed identification code reader that scans the identification code 3 when a cart loaded with parts passes by, instead of a portable identification code reader 9 carried by a transport worker. In addition, the identification code 3 may be attached to the cart 1 instead of the parts. Furthermore, the latch mechanism is not limited to the above-mentioned electromagnetic latch mechanism combining a solenoid and a spring, but may be any suitable type of latch mechanism that can lock and unlock using a suitable actuator such as a motor.

[0042] Furthermore, the locking mechanism 7 is not limited to the configuration of the above embodiment, and may be any type of locking mechanism that can restrict the entry of the dolly. For example, the locking mechanism may be configured to interfere with the body of the dolly instead of the wheels.

[0043] 9 and 10 show a second embodiment of the locking mechanism 7. The locking mechanism 7 of the second embodiment is configured to include a substantially rectangular base plate 41 fixed to the floor surface of a factory, a support shaft 42 erected at one end in the longitudinal direction of the base plate 41, a wheel stop bar 43 supported on the support shaft 42 so as to be openable and closable along the horizontal direction, an electromagnetic latch mechanism 44 that prevents the wheel stop bar 43 from rotating in one direction (i.e., the direction in which the cart enters), a photoelectric switch 45 that detects that the wheel stop bar 43 has rotated to the unlocked position, and a tape-shaped LED light 46 that serves as an indicator lamp that displays the state of the locking mechanism 7.

[0044] The wheel stopper bar 43 is always biased to return to a neutral state by the action of a spring 47 provided between the wheel stopper bar 43 and the support shaft 42.

[0045] The electromagnetic latch mechanism 44 has a latch bolt 51 with a tapered surface 51a at its tip, similar to the electromagnetic latch mechanism 24 of the embodiment described above, and engages with the tip edge of the wheel stop bar 43 on the side opposite to the approaching direction D of the bogie 1. When the solenoid of the electromagnetic latch mechanism 44 is not energized, the wheel stop bar 43 cannot rotate in a direction along the approaching direction D of the bogie 1 (counterclockwise direction in FIG. 9). On the other hand, rotation of the wheel stop bar 43 in the opposite direction is always permitted by the action of the tapered surface 51a of the latch bolt 51.

[0046] Therefore, basically the same effect as the lock mechanism 7 of the above-mentioned embodiment can be obtained. [Explanation of symbols]

[0047] 1...Trolley 2. Parts 3. Identification code 5…Truck loading position 7...Locking mechanism 9...Identification code reader 11…Controller 13…Spotlight 21…Base plate 23…Stepping board 23A…Front 23B…Rear 24...Electromagnetic latch mechanism 25...Photoelectric switch 26...LED light 31…Latch bolt 31a...Tapered surface

Claims

1. A cart for transporting a part having an identification code; a locking mechanism that is provided at each of the plurality of trolley loading positions and that prevents the trolley from entering in a locked state and allows the trolley to enter in an unlocked state; an identification code reader for reading the identification code; a controller that identifies a corresponding carriage loading position based on the identification code read by the identification code reader and unlocks a locking mechanism at the carriage loading position; A device for preventing erroneous dispensing of a trolley comprising:

2. The locking mechanism allows the movement of the cart in the pull-out direction when the cart has entered and is located at the cart loading position. The device for preventing erroneous dispensing of a trolley according to claim 1.

3. maintaining the locking mechanisms of the carriage loading positions other than the carriage loading position corresponding to the identification code in a locked state; The device for preventing erroneous dispensing of a trolley according to claim 1.

4. An indicator light is provided above each carriage loading position to indicate an unlocked carriage loading position. The device for preventing erroneous dispensing of a trolley according to claim 1.

5. each of the locking mechanisms includes a second indicator light for indicating when the locking mechanism is unlocked; The device for preventing erroneous dispensing of a trolley according to claim 1.

6. The lock mechanism is installed on a floor surface at the carriage loading position, It is located toward the front of the compartment of the cart loading position in correspondence with the wheels at the front of the entry direction, The device for preventing erroneous dispensing of a trolley according to claim 1.

7. The locking mechanism is A base plate fixed to a floor surface; A footboard supported rotatably about a rotation axis parallel to the base plate; A latch mechanism that prevents rotation of the footboard to lock it in place; Equipped with The device for preventing erroneous dispensing of a trolley according to claim 1.

8. The locking mechanism is A base plate fixed to a floor surface; A wheel stopper bar is supported on a support shaft erected on the base plate so as to be openable and closable along a horizontal direction; A latch mechanism that locks the wheel stop bar by preventing the wheel stop bar from rotating in the opening direction; Equipped with The device for preventing erroneous dispensing of a trolley according to claim 1.

9. The latch mechanism is A latch bolt having a tapered surface on the protruding portion, the protruding portion is biased in a protruding direction by a spring and retracts in response to a release signal from the controller; The tapered surface is provided at a position where it comes into contact with the step plate or the wheel stop bar as the step plate rotates or the wheel stop bar rotates, When the carriage is pulled out, the latch bolt is retracted by the tapered surface, thereby allowing the carriage to move in the pull-out direction. The device for preventing erroneous dispensing of a trolley according to claim 7 or 8.

10. The step plate has a front portion on the front side in the approach direction and a rear portion on the rear side in the approach direction, with the rotation axis between them, The front and rear portions are bent relative to each other at an obtuse angle, and when in a locked state, the rear portion is positioned along an upper surface of the base plate, and the front portion is positioned rising from the upper surface of the base plate; When the wheels of the cart pass, the footplate receives a rotational force. The device for preventing erroneous dispensing of a trolley according to claim 7.

11. An identification code is assigned to the parts transported by the cart moved by the worker, A locking mechanism is provided at each of the multiple trolley entry positions to prevent the trolley from entering, When a cart is transported to an area that includes multiple cart loading positions, the identification code is read, The controller identifies a corresponding carriage loading position based on the identification code, and unlocks the locking mechanism at the carriage loading position. A method for preventing the erroneous dispensing of trolleys.

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