Multi-level parking system

Abstract

To provide a parking device that can detect abnormal tilting of a pallet. To provide a monitoring method for a parking device that can detect abnormal tilting of a pallet. [Solution] A parking device according to one embodiment includes a pallet on which a vehicle can be placed, a pallet drive unit for raising and lowering the pallet, a first photoelectric sensor including a first light emitter and a first light receiving unit for receiving first light from the first light emitter, the sensor being positioned such that the pallet shields the first light in a part of the pallet's movement range, and a control unit that performs a predetermined control when the first shielding time during which the first light is shielded by the pallet is greater than or equal to a predetermined reference time.

Description

Technical Field

[0001] One embodiment of the present disclosure relates to a parking device for parking vehicles such as automobiles and a monitoring method thereof.

Background Art

[0002] As a parking device for vehicles, a so-called multi-stage parking device that places vehicles on a pallet and stacks them three-dimensionally for parking is known. In the multi-stage parking device, the pallet can be moved up and down or horizontally left and right, and vehicles can be loaded and unloaded onto the pallet that has been moved to the loading / unloading port.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] The lifting and lowering operation of the pallet in the multi-stage parking device is mainly performed by winding up or winding down the suspension chains installed on the pallet. When the pallet is lifted or lowered in this way, there is a risk that the horizontal posture of the pallet cannot be maintained due to synchronization errors of the plurality of suspension chains, etc., and the pallet may tilt. If the lifting and lowering operation of the pallet is performed in a tilted state of the pallet, the pallet may damage the device, or the vehicle placed on the pallet may tilt, damaging both the vehicle and the device.

[0005] In view of the above problems, one object of one embodiment of the present disclosure is to provide a parking device capable of detecting an abnormal tilt of a pallet.

[0006] Furthermore, in view of the above-mentioned problems, one of the objectives of this embodiment is to provide a method for monitoring a parking device that can detect abnormal tilting of a pallet. [Means for solving the problem]

[0007] A parking device according to one embodiment of the present disclosure includes: a pallet on which a vehicle can be placed; a pallet drive unit for raising and lowering the pallet; a first photoelectric sensor including a first light-emitting unit and a first light-receiving unit for receiving first light from the first light-emitting unit, the sensor being positioned such that the pallet shields the first light in a portion of the pallet's movement range; and a control unit that performs predetermined control when a first shielding time, during which the first light is shielded by the pallet, reaches a predetermined reference time.

[0008] The aforementioned predetermined control may involve stopping the upward and downward movement of the pallet.

[0009] The first photoelectric sensor may have an optical axis perpendicular to the longitudinal direction of the pallet.

[0010] The pallet has a wheel stop that defines a parking area in the direction of travel of the vehicle, and the first photoelectric sensor may be positioned so as to shield the first light from the outside of the wheel stop on the pallet.

[0011] The first photoelectric sensor may have an optical axis parallel to the longitudinal direction of the pallet.

[0012] The reference time may include a first reference time corresponding to the upward movement of the pallet and a second reference time corresponding to the downward movement of the pallet. When the pallet is moving upward by the pallet drive unit, the control unit executes the predetermined control when the first shielding time reaches the first reference time. When the pallet is moving downward by the pallet drive unit, the control unit executes the predetermined control when the first shielding time reaches the second reference time. The first reference time and the second reference time may be different.

[0013] The speed of the downward movement may be different from the speed of the upward movement.

[0014] The second reference time may be different from the first reference time.

[0015] The system may further include a second photoelectric sensor, which includes a second light-emitting unit and a second light-receiving unit that receives the second light from the second light-emitting unit, and is positioned such that the pallet shields the second light in a portion of the pallet's range of motion. The position where the first light is shielded by the pallet and the position where the second light is shielded by the pallet are different from each other. If the second light is not shielded by the pallet within a predetermined time from the timing when the first light is shielded by the pallet, or if the first light is not shielded by the pallet within a predetermined time from the timing when the second light is shielded by the pallet, the control unit may perform the predetermined control even if the first shielding time does not reach a predetermined reference time.

[0016] A parking device according to one embodiment of the present disclosure includes a pallet on which a vehicle can be placed, a pallet drive unit for raising and lowering the pallet, a first photoelectric sensor including a first light emitter and a first light receiving unit for receiving first light from the first light emitter, the pallet positioned such that it shields the first light in a part of the pallet's movement range, a second photoelectric sensor including a second light emitter and a second light receiving unit for receiving second light from the second light emitter, the pallet positioned such that it shields the second light in a part of the pallet's movement range, and the timing at which the first light is shielded by the pallet or The system includes a control unit that performs predetermined control based on the timing at which the second light is blocked by the palette, wherein the position at which the first light is blocked by the palette and the position at which the second light is blocked by the palette are different from each other, and if the second light is not blocked by the palette within a predetermined time from the timing at which the first light is blocked by the palette, or if the first light is not blocked by the palette within a predetermined time from the timing at which the second light is blocked by the palette, the control unit performs the predetermined control.

[0017] The predetermined time may include a first time corresponding to the upward movement of the pallet and a second time corresponding to the downward movement of the pallet, which is different from the first time. When the pallet is moving upward by the pallet drive unit, the pre-control unit may execute the predetermined control if the second light is not blocked by the pallet within the first time from the time when the first light is blocked by the pallet, or if the first light is not blocked by the pallet within the first time from the time when the second light is blocked by the pallet. When the pallet is moving downward by the pallet drive unit, the control unit may execute the predetermined control if the second light is not blocked by the pallet within the second time from the time when the first light is blocked by the pallet, or if the first light is not blocked by the pallet within the second time from the time when the second light is blocked by the pallet.

[0018] The second time may be different from the first time.

[0019] A monitoring method for a parking device according to an embodiment of the present disclosure includes a pallet on which a vehicle can be placed, a first light projecting unit, and a first light receiving unit that receives first light from the first light projecting unit, and a first optoelectronic sensor disposed such that the pallet shields the first light in a part of the movement range of the pallet. The monitoring method for the parking device includes performing predetermined control when a first shielding time during which the first light is shielded by the pallet reaches a predetermined reference time.

[0020] The first optoelectronic sensor may have an optical axis orthogonal to the longitudinal direction of the pallet.

[0021] The first optoelectronic sensor may have an optical axis parallel to the longitudinal direction of the pallet.

[0022] The reference time may include a first reference time corresponding to the upward movement of the pallet and a second reference time corresponding to the downward movement of the pallet. It is determined whether the pallet is moving upward or downward. As a result of the determination, if it is determined that the pallet is moving upward, it is determined whether the first shielding time has reached the first reference time. As a result of the determination, if it is determined that the pallet is moving downward, it is determined whether the first shielding time has reached the second reference time. The first reference time and the second reference time may be different.

[0023] The speed of the downward movement may be different from the speed of the upward movement.

[0024] The second reference time may be different from the first reference time.

[0025] The parking device includes a second light projecting unit and a second light receiving unit that receives the second light from the second light projecting unit, and further includes a second optoelectronic sensor arranged such that the pallet shields the second light in a part of the movement range of the pallet. The position where the first light is shielded by the pallet and the position where the second light is shielded by the pallet are different from each other. If the second light is not shielded by the pallet within a predetermined time from the timing when the first light is shielded by the pallet, or if the first light is not shielded by the pallet within a predetermined time from the timing when the second light is shielded by the pallet, even if the first shielding time does not reach a predetermined reference time, the parking device may further include performing the predetermined control.

[0026] A monitoring method for a parking device according to an embodiment of the present disclosure includes a pallet on which a vehicle can be placed, a pallet driving unit that moves the pallet up and down, a first light projecting unit and a first light receiving unit that receives the first light from the first light projecting unit, a first optoelectronic sensor arranged such that the pallet shields the first light in a part of the movement range of the pallet, a second light projecting unit and a second light receiving unit that receives the second light from the second light projecting unit, a second optoelectronic sensor arranged such that the pallet shields the second light in a part of the movement range of the pallet, and a control unit that executes predetermined control based on the timing when the first light is shielded by the pallet or the timing when the second light is shielded by the pallet. The position where the first light is shielded by the pallet and the position where the second light is shielded by the pallet are different from each other. The monitoring method for the parking device includes performing the predetermined control if the second light is not shielded by the pallet within a predetermined time from the timing when the first light is shielded by the pallet, or if the first light is not shielded by the pallet within a predetermined time from the timing when the second light is shielded by the pallet.

[0027] The predetermined time may include a first time corresponding to the upward movement of the pallet and a second time, different from the first time, corresponding to the downward movement of the pallet, and it is determined whether the pallet is moving upward or downward, and if the determination is that it is moving upward, within the predetermined first time from the time when the first light is blocked by the pallet The method may further include: if the second light is not blocked by the palette, or if the first light is not blocked by the palette within 1 hours from the time the second light is blocked by the palette, the predetermined control is executed; and if the result of the determination is a downward movement, the predetermined control is executed if the second light is not blocked by the palette within 2 hours from the time the first light is blocked by the palette, or if the first light is not blocked by the palette within 2 hours from the time the second light is blocked by the palette.

[0028] The speed of the downward operation may be different from the speed of the upward operation, and the second time may be different from the first time.

[0029] The aforementioned predetermined control may include stopping the upward and downward movement of the pallet. [Effects of the Invention]

[0030] According to a parking device according to one embodiment of the present disclosure, it is possible to detect an abnormal tilt of the pallet when the pallet is raised or lowered. As a result, if an abnormal tilt of the pallet is detected, the raising or lowering of the pallet can be stopped, preventing damage to the pallet, the vehicle placed on the pallet, or the parking device.

[0031] According to a parking device monitoring method according to one embodiment of the present disclosure, it is possible to detect abnormal tilting of the pallet when the pallet is raised or lowered. As a result, if an abnormal tilting of the pallet is detected, the raising or lowering of the pallet can be stopped, preventing damage to the pallet, the vehicle placed on the pallet, or the parking device. [Brief explanation of the drawing]

[0032] [Figure 1] This is a schematic side view showing the configuration of a parking device according to one embodiment of the present disclosure. [Figure 2] This is a schematic front view showing the configuration of a parking device according to one embodiment of the present disclosure. [Figure 3] This is a schematic block diagram showing the configuration of a parking device according to one embodiment of the present disclosure. [Figure 4] This diagram illustrates how the first light from the first photoelectric sensor is blocked by the palette. [Figure 5] This diagram illustrates how the first light from the first photoelectric sensor is blocked by the palette. [Figure 6] This is a flowchart illustrating the processing of a control unit in a parking device according to one embodiment of the present disclosure. [Figure 7] This is a schematic side view showing the configuration of a parking device according to one embodiment of the present disclosure. [Figure 8] This is a schematic front view showing the configuration of a parking device according to one embodiment of the present disclosure. [Figure 9] This is a schematic block diagram showing the configuration of a parking device according to one embodiment of the disclosure. [Figure 10] This diagram illustrates how the first light from the first photoelectric sensor and the second light from the second photoelectric sensor are shielded by the pallet. [Figure 11] This diagram illustrates how the first light from the first photoelectric sensor and the second light from the second photoelectric sensor are shielded by the pallet. [Figure 12] This is a flowchart illustrating the processing of a control unit in a parking device according to one embodiment of the present disclosure. [Figure 13] This is a schematic side view showing the configuration of a parking device according to one embodiment of the present disclosure. [Figure 14] This is a schematic front view showing the configuration of a parking device according to one embodiment of the present disclosure. [Figure 15]This diagram illustrates how the first light from the first photoelectric sensor is blocked by the palette. [Figure 16] This diagram illustrates how the first light from the first photoelectric sensor is blocked by the palette. [Figure 17] This figure illustrates an example of the placement position of a reflective photoelectric sensor according to a modified example of the present disclosure. [Figure 18] This figure illustrates an example of the placement position of a reflective photoelectric sensor according to a modified example of the present disclosure. [Modes for carrying out the invention]

[0033] The embodiments of this disclosure will be described below with reference to the drawings. However, the present invention can be implemented in many different ways and is not limited to the embodiments described below. In order to make the explanation clearer, the drawings may schematically represent the width, thickness, shape, etc. of each part compared to the actual embodiment, but these are merely examples and do not limit the interpretation of this disclosure. In addition, in this specification and each drawing, elements that are the same or similar as those described above with respect to previously shown drawings will be denoted with the same reference numeral (or a, b, A, B, etc. after a number), and detailed explanations may be omitted as appropriate. Furthermore, the letters "1st" and "2nd" appended to each element are convenient indicators used to distinguish each element and have no further meaning unless specifically explained.

[0034] In this specification, when a member or region is said to be "above (or below)" another member or region, unless otherwise specified, this includes not only cases where it is directly above (or directly below) the other member or region, but also cases where it is above (or below) the other member or region, that is, cases where another component is included between them above (or below) the other member or region.

[0035] Furthermore, in this specification, expressions such as "α includes A, B, or C," "α includes any one of A, B, and C," and "α includes one selected from the group consisting of A, B, and C" do not exclude cases where α includes multiple combinations of A through C unless otherwise specified. Moreover, these expressions do not exclude cases where α includes other elements.

[0036] <First Embodiment> [Configuration of parking device 100] Figure 1 is a schematic side view showing the configuration of a parking device 100 according to one embodiment of the present disclosure. Figure 2 is a schematic front view showing the configuration of a parking device 100 according to one embodiment of the present disclosure. Figures 1 and 2 show the main configuration of a parking device 100 according to one embodiment of the present disclosure. In this specification, the side of the parking device 100 with the entrance / exit is referred to as the front, and the opposite side as the rear. The direction from the front to the rear of the parking device 100, or the direction from the rear to the front of the parking device 100 (i.e., the direction in which a vehicle V enters or exits the parking device 100) is referred to as the front-rear direction.

[0037] The parking system 100 is a multi-story parking system capable of accommodating multiple vehicles V. The parking system 100 has a skeletal structure mainly composed of support columns 102 and beams 103 installed between the support columns 102, and has multiple partitioned vehicle loading areas capable of accommodating one vehicle V. The parking system 100 is equipped with pallets 104 on which vehicles V are loaded.

[0038] In this embodiment, the parking device 100 has, for example, four levels in the vertical direction (up and down direction) where vehicles V are stacked, and four rows in the horizontal direction (left and right direction) where vehicles V are placed side by side. The parking device 100 requires a preliminary space for raising, lowering, or moving vehicles V. Excluding the preliminary space, the parking device 100 can park and accommodate up to 10 vehicles V. That is, the parking device 100 has 10 vehicle loading areas indicated by PS1 to PS10. Pallets 104 on which vehicles V are placed are installed in each vehicle loading area.

[0039] The parking device 100 of this embodiment is not limited to the structure shown in Figures 1 and 2. The parking device 100 may have a structure with fewer than four levels or five or more levels in the vertical direction, and may have a structure with fewer than four or five or more units in the horizontal direction.

[0040] In the parking device 100, the pallet 104 is moved up and down vertically and horizontally horizontally to move the target pallet 104 to the entrance / exit, thereby enabling the vehicle V to be loaded and unloaded.

[0041] The parking device 100 shown in Figures 1 and 2 uses a method of raising and lowering 2 to 4 pallets 104 on a 1st level where no pallets 104 exist. However, the parking device 100 is not limited to this method. For example, the parking device 100 according to this embodiment can be adapted to various methods, such as a method in which three pallets 104 are installed on the 1st level of the parking device 100, with the space excluding the reserve space used as a vehicle loading area, a method in which pallets 104 are installed on the 1st level of the parking device 100, and the 1st level pallet 104 is sunk into an underground pit, and the 2nd to 4th levels pallets 104 are lowered to the 1st level, a method in which 1 to 3 pallets 104 are slid in the front-to-back direction, and the 2nd to 4th levels pallets 104 are lowered to the 1st level, or a combination of these methods.

[0042] The pallet 104 may be provided with a wheel stop 105 to prevent the vehicle V from moving to the rear. The wheel stop 105 defines the parking area in the direction of travel of the vehicle V on the pallet 104. The wheel stop 105 is provided on the rear side of the pallet 104. The height of the wheel stop 105 is lower than the height of the vehicle V. The wheel stop 105 suppresses the movement of the rear wheels of the vehicle V to the rear and prevents the vehicle V from extending outside the pallet 104. When the vehicle V enters the parking device 100 from the front, the wheel stop 105 may suppress the movement of the front wheels of the vehicle V.

[0043] The pallet 104 is provided so as to be able to move up and down along the support column 102 by an elevator 106. The pallet 104 is also provided so as to be able to move along the horizontal direction (depth direction in Figure 1, left-right direction in Figure 2). The pallet 104 may also move along horizontal guide rails (not shown) provided parallel to the horizontal direction. Within the skeletal structure, the pallets 104 are provided with sufficient spacing between them so that the vehicles do not interfere with each other when multiple vehicles V are stacked vertically.

[0044] The parking system 100 is operated by a control panel 214. The control panel 214 is located on the outside of the parking system 100. For example, as shown in Figure 1, the control panel 214 may be attached to a support column 102 near the entrance / exit of the parking system 100 (lower right side of the figure).

[0045] The control panel 214 communicates with the control unit 200, which controls the parking system 100, via wired or wireless means. The control unit 200 controls all operations of the parking system 100, including the raising and lowering of multiple pallets 104 and the opening and closing of the gate 108. Figure 1 shows an example in which the control device 200 is located behind the vehicle V.

[0046] The first level (ground level) of the parking device 100 has an entrance / exit for vehicles V. A gate 108 is installed on the first level. When a vehicle V is exiting, the gate 108 opens when the pallet 104 is moved to the entrance / exit, and is closed when the gate 108 is closed using the control panel 214 after the vehicle V has exited. When a vehicle V is entering, the gate 108 opens when the gate 108 is opened using the control panel 214, and is closed when the control panel 214 is operated after the vehicle V has entered. The gate 108 is closed except when it is opened to allow a vehicle V to enter or exit. Therefore, the gate 108 is closed even when the pallet 104 is moving. Closing the gate 108 normally prevents people from entering the parking device 100.

[0047] The sensor 220 is installed to detect objects (people or objects) in a predetermined area in the closing direction of the gate 108 in order to ensure safety when closing the gate 108. In this example, the sensor 220 is attached to a support column 102 near the entrance / exit of the parking device 100 (lower right side of the figure). The sensor 220 may also be attached to a portion that protrudes from the support column 102 towards the gate 108, so that a detection range is formed between the lower surface of the gate 108 and the ground.

[0048] The mounting position of the sensor 220 is not limited to the support column 102. The sensor 220 may be mounted on the gate 108. For example, the sensor 220 may be mounted on the underside of the gate 108. When the sensor 220 is mounted on the gate 108, the predetermined area that the sensor 200 can detect will move with the opening and closing of the gate 108. Note that the predetermined area in the closing direction of the gate 108 is not limited to the area between the gate 108 and the ground, but can be any area in the closing direction. For example, this predetermined area may include the vicinity of the area between the gate 108 and the ground. In other words, it may include the area between the vicinity of the gate 108 and the ground.

[0049] The notification unit 222 notifies users when the gate 108 is closed or opened. In this example, the notification unit 222 is mounted on the top of the support column 102 near the entrance / exit of the parking device 100 (lower right side of the diagram).

[0050] The parking device 100 includes a first photoelectric sensor 224 that detects the tilt of the pallet 104 when the pallet 104 is raised or lowered. The first photoelectric sensor 224 includes a first light-emitting unit 224a and a first light-receiving unit 224b that receives light (first light) from the first light-emitting unit 224a. In Figures 1 and 2, two pairs of first photoelectric sensors 224 are installed as an example, but the number of first photoelectric sensors 224 is not limited to this, and one or more pairs are sufficient.

[0051] The first light-emitting unit 224a and the first light-receiving unit 224b of the first photoelectric sensor 224 are positioned such that the pallet 104 blocks the first light emitted from the first light-emitting unit 224a within a portion of the pallet 104's movement range (up and down range). In other words, the first photoelectric sensor 224 is installed at a stationary position outside the pallet 104's movement range (up and down range) such that its optical axis overlaps with the pallet 104's movement range (up and down range).

[0052] For example, as shown in Figures 1 and 2, the first photoelectric sensor 224 may be installed on a beam 103 that spans between support columns 102. In this embodiment, as an example, the first photoelectric sensor 224 is installed so as to have an optical axis perpendicular to the longitudinal direction of the pallet 104. In other words, in this embodiment, the first photoelectric sensor 224 is installed in the parking device 100 so as to have an optical axis perpendicular to the left-right direction (horizontal direction) when vehicles V are placed side by side in the parking device 100. The first photoelectric sensor 224 may be installed on a beam 103 that spans between adjacent support columns 102 in the front-rear direction. The installation position of the first photoelectric sensor 224 is not limited to the beam 103, but may also be installed on the support columns 102. Furthermore, if the parking device 100 has an outer wall, the first photoelectric sensor 224 may be installed on the outer wall.

[0053] As described above, the first photoelectric sensor 224 is positioned such that the pallet 104 shields the first light emitted from the first light-emitting unit 224a within a portion of the pallet 104's movement range (lifting range). Preferably, the first photoelectric sensor 224 is installed in a position where the first light emitted from the first light-emitting unit 224a is not shielded by the vehicle V placed on the pallet 104. In other words, it is preferable that the body of the vehicle V placed on the pallet 104 does not enter the optical axis of the first photoelectric sensor 224 during the lifting and lowering operation of the pallet 104. In order to detect the tilt of the pallet 104 when it is lifted or lowered, the time (first shielding time) during which the first light emitted from the first light-emitting unit 224a of the first photoelectric sensor 224 is shielded by the pallet 104 is detected. If the body of vehicle V blocks the light emitted from the first light-emitting unit 224a (first light), the time during which the first light is blocked by the pallet 104 (first blocking time) may be incorrectly detected, potentially causing a malfunction in the parking device 100. Therefore, by installing the first photoelectric sensor 224 in a position where the first light emitted from the first light-emitting unit 224a is not blocked by the vehicle V placed on the pallet 104, the accuracy of detecting the tilt of the pallet 104 can be improved.

[0054] For example, if the pallet 104 is provided with a wheel stop 105 to prevent the vehicle V from moving toward the rear, the first photoelectric sensor 224 may be installed a predetermined distance to the rear of the wheel stop 105. This prevents the light emitted from the first light-emitting unit 224a of the first photoelectric sensor 224 from being blocked by the vehicle body of the vehicle V placed on the pallet 104. The installation position of the first photoelectric sensor 224 is not limited to this. For example, the first photoelectric sensor 224 may be installed on the front side.

[0055] Figure 3 is a block diagram showing the schematic configuration of a parking device 100 according to one embodiment of the present disclosure. The parking device 100 comprises a control device 200, an operation panel 214, a pallet drive device 216, a gate drive device 218, a pallet 104, a gate 108, a sensor 220, a notification unit 222, and a first photoelectric sensor 224.

[0056] The control device 200 includes a storage unit 204 and a control unit 206.

[0057] The memory unit 204 is a logical memory area, and is a memory area within the CPU, such as the main memory or secondary memory. The memory unit 204 includes memory devices such as RAM and ROM. The memory unit 204 stores programs and the like that enable the control device 200 to implement various functions.

[0058] The control unit 206 is a CPU (Central Processing Unit). The control unit 206 executes programs stored in the memory unit 204 using the CPU to realize various functions in the control device 200.

[0059] The control unit 206 transmits instruction signals to the pallet drive unit 216 and the gate drive unit 218 regarding the driving of the pallet 104 and the gate 108. When the control panel 214 is operated by a user, the control unit 206 transmits instruction signals to the pallet drive unit 216 and the gate drive unit 218 regarding the driving of the pallet 104 and the gate 108 based on the information received from the control panel 214. The control unit 206 also transmits instruction signals to the notification unit 222 regarding the driving of the notification unit 222 based on the information received from the sensor 220. Furthermore, the control unit 206 receives a detection signal output from the first photoelectric sensor 224 and performs predetermined control based on the received detection signal. For example, the control unit 206 transmits an instruction signal regarding the driving of the pallet 104 to the pallet drive unit 216 based on the detection signal.

[0060] The programs executed by the control unit 206 may be provided stored on a computer-readable recording medium such as a magnetic recording medium, optical recording medium, magneto-optical recording medium, or semiconductor memory. Alternatively, each program may be downloaded via a network.

[0061] The control panel 214 is a user interface in which the user inputs instructions for automatic operation (such as specifying the number of pallet 104 or instructing the opening and closing of gate 108) to the control device 200. When the control panel 214 receives instructions for automatic operation from the user, it transmits information about the pallet 104 to be operated on and information about the operation to be operated on to the control device 200.

[0062] The pallet drive device 216 drives the pallet 104 based on the instruction signal for driving the pallet 104 received from the control unit 206.

[0063] The gate drive unit 218 drives the gate 108 based on the instruction signal for driving the gate 108 received from the control unit 206.

[0064] Sensor 220 detects objects present in a predetermined area in the closing direction of gate 108. Sensor 220 is a non-contact sensor, such as an optical sensor, ultrasonic sensor, infrared sensor, or image recognition sensor (analysis of images captured by a camera). Sensor 220 may also include a contact sensor in place of or in conjunction with the non-contact sensor. The contact sensor may be, for example, a sensor that detects contact with the lower surface of gate 108, or a sensor that detects contact with the ground directly below gate 108. If the sensor detects contact with the lower surface of gate 108, it may be, for example, a piezoelectric sensor that generates power by pressure, or a switch using a movable contact. Alternatively, the current and voltage of the motor that drives gate 108 may be monitored, and contact with gate 108 may be detected by detecting an overload condition.

[0065] The notification unit 222 notifies users of the closing and opening of gate 108. The notification unit 222 may be, for example, a speaker, display, or light-emitting device.

[0066] The first photoelectric sensor 224 detects the shielding of the first light emitted from the first light-emitting unit 224a by the pallet 104. The light source used in the first light-emitting unit 224a may be a laser, visible light, or infrared light. The first photoelectric sensor 224 outputs a detection signal to the control unit 206. The detection signal is a signal indicating the amount of first light emitted from the first light-emitting unit 224a that is received by the first light-receiving unit 224b.

[0067] Figures 4 and 5 illustrate how the first light emitted from the first light-emitting section 224a of the first photoelectric sensor 224 is shielded by the pallet 104. As an example, Figures 4 and 5 illustrate a case in which the first photoelectric sensor 224, installed on a beam 103 (not shown) that spans between adjacent support columns 102 in the front-rear direction, detects the tilt of the pallet 104 in the left-right direction (horizontal direction) when the pallet 104 is lowered.

[0068] Figure 4 illustrates how the first light emitted from the first light-emitting section 224a of the first photoelectric sensor 224 is blocked by the pallet 104 when the pallet 104 is not tilted horizontally.

[0069] As shown in Figure 4(A), if there is no obstruction on the optical axis between the first light-emitting unit 224a and the first light-receiving unit 224b, the first light emitted from the first light-emitting unit 224a is received by the first light-receiving unit 224b.

[0070] As shown in Figure 4(B), when the pallet 104 descends and enters the optical axis between the first light-emitting unit 224a and the first light-receiving unit 224b, the first light emitted from the first light-emitting unit 224a is blocked by the pallet 104. At this time, the amount of first light received by the first light-receiving unit 224b changes from the amount of first light received by the first light-receiving unit 224b in the state shown in Figure 4(A).

[0071] As the palette 104 descends further and moves off the optical axis between the first light-emitting unit 224a and the first light-receiving unit 224b, as shown in Figure 4(C), the amount of first light received by the first light-receiving unit 224b returns to the amount of first light received by the first light-receiving unit 224b in the state shown in Figure 4(A).

[0072] Figure 5 illustrates how the first light emitted from the first light-emitting section 224a of the first photoelectric sensor 224 is blocked by the pallet 104 when the pallet 104 is tilted horizontally.

[0073] As shown in Figure 5(A), if there is no obstruction on the optical axis between the first light-emitting unit 224a and the first light-receiving unit 224b, the first light emitted from the first light-emitting unit 224a is received by the first light-receiving unit 224b.

[0074] As shown in Figure 5(B), when the pallet 104 descends and enters the optical axis between the first light-emitting unit 224a and the first light-receiving unit 224b, the first light emitted from the first light-emitting unit 224a is blocked by the pallet 104. At this time, the amount of first light received by the first light-receiving unit 224b changes from the amount of first light received by the first light-receiving unit 224b in the state shown in Figure 5(A).

[0075] As shown in Figure 5(C), when the pallet 104 is tilted, even if the pallet 104 descends further, the pallet 104 remains on the optical axis between the first light-emitting unit 224a and the first light-receiving unit 224b, and the first light emitted from the first light-emitting unit 224a is blocked by the pallet 104. At this time, the amount of first light received by the first light-receiving unit 224b is approximately the same as the amount of first light received by the first light-receiving unit 224b in the state shown in Figure 5(B).

[0076] As the palette 104 descends further and moves off the optical axis between the first light-emitting unit 224a and the first light-receiving unit 224b, as shown in Figure 5(D), the amount of first light received by the first light-receiving unit 224b returns to the amount of first light received by the first light-receiving unit 224b in the state shown in Figure 5(A).

[0077] A detection signal indicating the amount of first light received by the first light receiving unit 224b of the first photoelectric sensor 224 is output to the control unit 206 of the control device 200. Based on the received detection signal, the control unit 206 determines whether the shielding time of the first light by the pallet 104 (first shielding time) has reached a predetermined reference time. If the first shielding time has not reached the predetermined reference time, that is, if the first shielding time is less than the predetermined reference time, the control unit 206 determines that there is no horizontal tilt of the pallet 104 and maintains the downward movement of the pallet 104. On the other hand, if the first shielding time has reached the predetermined reference time, that is, if the first shielding time is equal to or greater than the predetermined reference time, the control unit 206 determines that the pallet 104 is tilted horizontally, generates an instruction signal to stop the downward movement of the pallet 104, and transmits it to the pallet drive device 216.

[0078] As shown in Figure 5, when the pallet 104 is tilted horizontally, the time that the pallet 104 is on the optical axis between the first light-emitting unit 224a and the first light-receiving unit 224b is longer than when the pallet 104 is not tilted horizontally, as shown in Figure 4. In other words, when the pallet 104 is tilted horizontally, the first shielding time during which the pallet 104 shields the first light traveling from the first light-emitting unit 224a to the first light-receiving unit 224b is longer than the first shielding time when the pallet 104 is not tilted horizontally. Therefore, by pre-determining a predetermined reference time and determining whether the first shielding time is less than the predetermined reference time or greater than or equal to the predetermined reference time, it is possible to determine whether the pallet 104 is tilted horizontally or not.

[0079] A predetermined reference time can be set in advance by the administrator of the parking device 100 based on the movement speed of the pallet 104. The predetermined reference time is stored in advance in the memory unit 204 of the control device 200. The predetermined reference time may be changed by the administrator of the parking device 100.

[0080] The upward and downward speeds of the pallet 104 may be different. If the upward and downward speeds of the pallet 104 are different, the predetermined reference time may include a reference time corresponding to the upward movement of the pallet 104 (first reference time) and a reference time corresponding to the downward movement of the pallet 104 (second reference time). In this embodiment, the downward speed of the pallet 104 may be faster than the upward speed of the pallet. In this case, the second reference time corresponding to the downward movement of the pallet 104 is shorter than the first reference time corresponding to the upward movement of the pallet 104. The control unit 206 determines whether the pallet 104 is moving upward or downward. If the pallet 104 is moving upward, the control unit 206 determines whether the first shielding time has reached the first reference time corresponding to the upward movement of the pallet 104, in other words, whether the first shielding time is less than the first reference time or is equal to or greater than the first reference time, and determines whether the pallet 104 is tilted horizontally. When the pallet 104 is moving downward, the control unit 206 determines whether the first shielding time has reached the second reference time corresponding to the downward movement of the pallet 104, in other words, whether the first shielding time is less than the second reference time or is equal to or greater than the second reference time, and determines whether or not the pallet 104 is tilted horizontally.

[0081] [Detection of horizontal tilt of the pallet] As described above, the control unit 206 detects whether or not the pallet 104 is tilted horizontally based on the detection signal output from the first photoelectric sensor 224.

[0082] Figure 6 is a flowchart illustrating the processing of the control unit 206 for detecting whether or not the pallet 104 is tilted horizontally in the parking device 100 according to this embodiment. In this embodiment, the explanation is based on the premise that the upward speed and downward speed of the pallet 104 are different.

[0083] When the parking device 100 starts operation, the control unit 206 checks whether the parking device 100 is in an automatic operation state (S601). If the parking device 100 is in automatic operation state (S601; YES), the control unit 206 checks whether the pallet 104 is to be raised or lowered (S602). On the other hand, if the parking device 100 is not in an automatic operation state (S601; NO), the control unit 206 repeats the process of S601 until it enters automatic operation mode. Here, cases where the parking device 100 is not in an automatic operation state include, for example, when the parking device 100 is in manual operation mode, or when it has stopped due to an error during automatic operation.

[0084] If the pallet 104 is to be moved upward, the process proceeds to S603. If the pallet 104 is to be moved downward, the process proceeds to S610. On the other hand, if the pallet 104 is neither being moved upward nor downward (S602; NO), the control unit 206 repeats the process of S602 until the pallet 104 is to be moved upward or downward. Here, cases where the pallet 104 is neither being moved upward nor downward include, for example, when the pallet 104 is being moved horizontally or when the gate 108 is being opened or closed.

[0085] When the pallet 104 is moved upward (S602; upward movement operation), the control unit 206 obtains a reference time (first reference time) corresponding to the upward movement of the pallet 104 from the storage unit 204 (S603).

[0086] Next, the control unit 206 determines whether or not the shielding of the first light has started by the pallet 104 (S604). Based on the detection signal output from the first photoelectric sensor 224 indicating the amount of light received by the first light, the control unit 206 determines whether or not the shielding of the first light has started. If the shielding of the first light has started (S604; YES), the control unit 206 starts the timer (S605).

[0087] The control unit 206 checks, using a timer, whether the shielding of the first light by the pallet 104 is maintained until the first reference time is reached. Specifically, if the first reference time is not reached (S606; NO), the control unit 206 determines, based on the detection signal, whether the first light is being shielded by the pallet 104 (S607). If the shielding of the first light by the pallet 104 has ended (S607; NO), the control unit 206 stops the timer (S608) and terminates the process. Here, if the shielding of the first light by the pallet 104 has ended before the first reference time is reached, it means that the shielding time of the first light by the pallet 104 (first shielding time) is less than the first reference time.

[0088] On the other hand, if the shielding of the first light by the pallet 104 is not yet complete (S607; YES), the control unit 206 repeats the process of S607 while counting with the timer until the first reference time is reached.

[0089] When the first reference time is reached (S606; YES), the control unit 206 determines that the pallet 104 is tilted horizontally and outputs a stop instruction signal to stop the upward movement of the pallet 104 (S609), and terminates the process. The output stop instruction signal is transmitted to the pallet drive unit 216.

[0090] When the pallet 104 is moved downward (S602; downward movement operation), the control unit 206 obtains a reference time (second reference time) corresponding to the downward movement of the pallet 104 from the storage unit 204 (S610). The second reference time may be shorter than the first reference time corresponding to the upward movement of the pallet 104.

[0091] Next, the control unit 206 determines whether or not the shielding of the first light has begun by the pallet 104 (S611). Based on the detection signal output from the first photoelectric sensor 224 indicating the amount of light received by the first light, the control unit 206 determines whether or not the shielding of the first light has begun. If the shielding of the first light has begun (S611; YES), the control unit 206 starts the timer (S612).

[0092] The control unit 206 counts with a timer and checks whether the shielding of the first light by the pallet 104 is maintained until the second reference time is reached. Specifically, if the second reference time is not reached (S613; NO), the control unit 206 determines, based on the detection signal, whether the first light is being shielded by the pallet 104 (S614). If the shielding of the first light by the pallet 104 has ended (S614; NO), the control unit 206 stops the timer (S615) and terminates the process. Here, if the shielding of the first light by the pallet 104 has ended before the second reference time is reached, it means that the shielding time of the first light by the pallet 104 (first shielding time) is less than the second reference time.

[0093] On the other hand, if the shielding of the first light by the palette 104 is not yet complete (S614; YES), the control unit 206 repeats the process of S614 while counting with the timer until the second reference time is reached.

[0094] When the second reference time is reached (S613; YES), the control unit 206 determines that the pallet 104 is tilted horizontally and outputs a stop instruction signal to stop the downward movement of the pallet 104 (S609), and terminates the process. The outputted stop instruction signal is transmitted to the pallet drive unit 216.

[0095] The above describes the flow for the control unit 206 to detect whether or not the pallet 104 is tilted horizontally in the parking device 100 according to this embodiment. However, the flow according to this embodiment is not limited to the flow described with reference to Figure 6.

[0096] For example, if the upward and downward speeds of the pallet 104 are the same, the control unit 206 may, instead of acquiring a first reference time or a second reference time, acquire a reference time common to both the upward and downward movement of the pallet 104 from the storage unit 204. In this case, when the blocking of the first light begins, the control unit 206 checks whether the blocking of the first light by the pallet 104 is maintained until the timer reaches the reference time.

[0097] <Second Embodiment> In the first embodiment described above, the detection of the horizontal tilt of the pallet 104 by the first photoelectric sensor 224 was explained. In this embodiment, the detection of the tilt of the pallet 104 in the front-rear direction (the direction in which the vehicle V enters and exits the parking device 100) by multiple photoelectric sensors will be explained.

[0098] [Configuration of parking system 100A] Figure 7 is a schematic side view showing the configuration of the parking device 100A according to this embodiment. Figure 8 is a schematic front view showing the configuration of the parking device 100A according to this embodiment. Figures 7 and 8 show the main configuration of the parking device 100A according to this embodiment.

[0099] A parking device 100A according to one embodiment of this disclosure has the same configuration as the parking device 100 according to the first embodiment described with reference to Figures 1 and 2, except that it includes a second photoelectric sensor 226. Therefore, the following description will mainly focus on the second photoelectric sensor 226, and detailed descriptions of other components will be omitted.

[0100] The parking device 100A includes a first photoelectric sensor 224 and a second photoelectric sensor 226. The second photoelectric sensor 226 includes a second light-emitting unit 226a and a second light-receiving unit 226b that receives light (second light) from the second light-emitting unit 226a. In Figure 7, as an example, two pairs of first photoelectric sensors 224 and two pairs of second photoelectric sensors 226 are installed, but the number of first photoelectric sensors 224 and second photoelectric sensors 226 is not limited to this, and one or more pairs are sufficient.

[0101] The second light-emitting unit 226a and the second light-receiving unit 226b of the second photoelectric sensor 226 are positioned such that the pallet 104 shields the second light emitted from the second light-emitting unit 226a within a portion of the pallet 104's movement range (up and down range). In other words, the second photoelectric sensor 226 is installed at a stationary position outside the movement range (up and down range) of the pallet 104 such that its optical axis overlaps with the movement range (up and down range) of the pallet 104. The position where the first light emitted from the first light-emitting unit 224a of the first photoelectric sensor 224 is shielded by the pallet 104 is different from the position where the second light emitted from the second light-emitting unit 226a of the second photoelectric sensor 226 is shielded by the pallet 104.

[0102] For example, as shown in Figures 7 and 8, the second photoelectric sensor 226 may be installed on a beam 103 that spans between the support columns 102. In this embodiment, as an example, the second photoelectric sensor 226 is installed so as to have an optical axis perpendicular to the longitudinal direction of the pallet 104. In other words, in this embodiment, the second photoelectric sensor 226 is installed in the parking device 100 so as to have an optical axis perpendicular to the left-right direction (horizontal direction) when the vehicles V are placed side by side. The second photoelectric sensor 226 may be installed on a beam 103 that spans between adjacent support columns 102 in the front-rear direction, similar to the first photoelectric sensor 224. The installation position of the second photoelectric sensor 226 is not limited to the beam 103, but may also be installed on the support columns 102. Furthermore, if the parking device 100 has an outer wall, the second photoelectric sensor 226 may be installed on the outer wall. In Figure 8, when viewed from the front (entrance / exit) side of the parking device 100A, the installation positions of the second light-emitting unit 226a and the second light-receiving unit 226b of the second photoelectric sensor 226 overlap with the installation positions of the first light-emitting unit 224a and the first light-receiving unit 224b of the first photoelectric sensor 224. Therefore, the depiction of the first photoelectric sensor 224 is omitted in Figure 8.

[0103] As an example, in this embodiment, the optical axis of the second photoelectric sensor 226 is parallel to the optical axis of the first photoelectric sensor 224. The position where the second light emitted from the second light-emitting unit 226a of the second photoelectric sensor 226 toward the second light-receiving unit 226b is shielded by the pallet 104 is separated by a predetermined distance in the longitudinal direction of the pallet 104 from the position where the first light emitted from the first light-emitting unit 224a of the first photoelectric sensor 224 toward the first light-receiving unit 224b is shielded by the pallet 1004. In other words, the optical axis of the second photoelectric sensor 226 and the optical axis of the first photoelectric sensor 224 are separated by a predetermined distance in the longitudinal direction of the pallet 104.

[0104] As described above, the second photoelectric sensor 226 is positioned such that the pallet 104 shields the second light emitted from the second light-emitting unit 226a within a portion of the pallet 104's movement range (lifting range). Similar to the first photoelectric sensor 224, it is preferable that the second photoelectric sensor 226 is installed in a position where the second light emitted from the second light-emitting unit 224a is not shielded by the vehicle V placed on the pallet 104. In other words, it is preferable that the body of the vehicle V placed on the pallet 104 does not enter the optical axis of the second photoelectric sensor 226 during the lifting operation of the pallet 104. In order to detect the tilt of the pallet 104 when it is raised or lowered, the timing at which the first light emitted from the first light-emitting unit 224a of the first photoelectric sensor 224 is blocked by the pallet 104, and the timing at which the second light emitted from the first light-emitting unit 226a of the second photoelectric sensor 226 is blocked by the pallet 104 are detected. If the body of the vehicle V blocks the light emitted from the first light-emitting unit 224a (first light) or the light emitted from the second light-emitting unit 226a (second light), the timing at which the first light or the second light is blocked by the pallet 104 may be incorrectly detected, which may cause a malfunction in the parking device 100A. Therefore, by installing the first photoelectric sensor 224 and the second photoelectric sensor 226 in positions where the light emitted from the first light-emitting unit 224a and the second light-emitting unit 226a is not obstructed by the vehicle V placed on the pallet 104, the accuracy of detecting the tilt of the pallet 104 can be improved.

[0105] In this embodiment, the first photoelectric sensor 224 may be installed at a predetermined distance to the rear from the position where the wheel stop 105 is installed. The second photoelectric sensor 226 may be installed at a predetermined distance to the rear from the position corresponding to the front end of the pallet 104. However, in this embodiment, the installation positions of the first photoelectric sensor 224 and the second photoelectric sensor 226 are not limited to these.

[0106] Figure 9 is a block diagram showing the schematic configuration of the parking device 100A according to this embodiment. The parking device 100 includes a control device 200, an operation panel 214, a pallet drive device 216, a gate drive device 218, a pallet 104, a gate 108, a sensor 220, a notification unit 222, a first photoelectric sensor 224, and a second photoelectric sensor 226. As described above, the parking device 100A according to this embodiment has the same configuration as the parking device 100 according to the first embodiment described with reference to Figure 3, except for the inclusion of the second photoelectric sensor 226. Therefore, the following will mainly describe the second photoelectric sensor 226, and detailed descriptions of the other components will be omitted.

[0107] The second photoelectric sensor 226 detects the shielding of the second light emitted from the second light-emitting unit 226a by the pallet 104. The light source used in the second light-emitting unit 226a may be a laser, visible light, or infrared light. The second photoelectric sensor 226 outputs a detection signal to the control unit 206. The detection signal is a signal indicating the amount of second light emitted from the second light-emitting unit 226a that is received by the second light-receiving unit 226b.

[0108] The control unit 206 receives detection signals output from the first photoelectric sensor 224 and the second photoelectric sensor 226, and performs predetermined control based on the received detection signals. For example, based on the detection signals, the control unit 206 transmits instruction signals regarding the driving of the pallet 104 to the pallet drive device 216.

[0109] Figures 10 and 11 illustrate how the first light emitted from the first light-emitting section 224a of the first photoelectric sensor 224 and the second light emitted from the second light-emitting section 226a of the second photoelectric sensor 226 are shielded by the pallet 104. As an example, Figures 10 and 11 illustrate a case in which the first photoelectric sensor 224 and the second photoelectric sensor 226, which are installed on a beam 103 (not shown) that is erected between adjacent support columns 102 in the front-rear direction, detect the tilt of the pallet 104 in the front-rear direction (from the front to the back of the parking device 100A, or from the back to the front of the parking device 100A) when the pallet 104 is lowered.

[0110] Figure 10 illustrates how the first light emitted from the first light-emitting section 224a of the first photoelectric sensor 224 and the second light emitted from the second light-emitting section 226a of the second photoelectric sensor 226 are shielded by the pallet 104 when the pallet 104 is not tilted in the front-to-back direction.

[0111] As shown in Figure 10(A), if there is no obstruction between the optical axis of the first photoelectric sensor 224 and the optical axis of the second photoelectric sensor 226, the first light emitted from the first light-emitting unit 224a of the first photoelectric sensor 224 is received by the first light-receiving unit 224b (not shown) which is horizontally opposed, and the second light emitted from the second light-emitting unit 226a of the second photoelectric sensor 226 is received by the second light-receiving unit 226b (not shown) which is horizontally opposed.

[0112] As shown in Figure 10(B), when the pallet 104 descends and enters the optical axis of the first photoelectric sensor 224 and the optical axis of the second photoelectric sensor 226, the first light emitted from the first light-emitting unit 224a and the second light emitted from the second light-emitting unit 226a are shielded by the pallet 104. At this time, the amount of light received by the first light-receiving unit 224b and the amount of light received by the second light-receiving unit 226b change from the amount of light received by the first light-receiving unit 224b and the amount of light received by the second light-receiving unit 226b in the state shown in Figure 10(A).

[0113] As the pallet 104 descends further and moves away from the optical axis of the first photoelectric sensor 224 and the optical axis of the second photoelectric sensor 226, as shown in Figure 10(C), the amount of first light received by the first light receiving unit 224b and the amount of second light received by the second light receiving unit 226b return to the amounts of first light received by the first light receiving unit 224b and the amount of second light received by the second light receiving unit 226b as shown in Figure 10(A).

[0114] Figure 11 illustrates how the first light emitted from the first light-emitting section 224a of the first photoelectric sensor 224 and the second light emitted from the second light-emitting section 226a of the second photoelectric sensor 226 are shielded by the pallet 104 when the pallet 104 is tilted in the front-to-back direction. As an example, Figure 11 illustrates the case where the pallet 104 is tilted downward from the rear side to the front side.

[0115] As shown in Figure 11(A), if there are no obstructions on the optical axis of the first photoelectric sensor 224 and the optical axis of the second photoelectric sensor 226, the first light emitted from the first light-emitting unit 224a of the first photoelectric sensor 224 is received by the first light-receiving unit 224b (not shown) which is horizontally opposed, and the second light emitted from the second light-emitting unit 226a of the second photoelectric sensor 226 is received by the second light-receiving unit 226b (not shown) which is horizontally opposed.

[0116] As shown in Figure 11(B), when the pallet 104 descends and enters the optical axis of the second photoelectric sensor 226, the second light emitted from the second light-emitting unit 226a is blocked by the pallet 104. At this time, the amount of second light received by the second light-receiving unit 226b changes from the amount of second light received by the second light-receiving unit 226b in the state shown in Figure 11(A).

[0117] On the other hand, in this example, since the pallet 104 is tilted downward from the back to the front, at the timing shown in Figure 11(B), the pallet 104 is not in line with the optical axis of the first photoelectric sensor 224. Therefore, the first light emitted from the first light-emitting unit 224a is received by the first light-receiving unit 224b (not shown), which is horizontally opposed to it. Consequently, the amount of first light received by the first light-receiving unit 224b maintains the amount of first light received by the second light-receiving unit 224b in the state shown in Figure 11(A).

[0118] As shown in Figure 11(C), when the pallet 104 descends further and enters the optical axis of the first photoelectric sensor 224, the first light emitted from the first light-emitting unit 224a is blocked by the pallet 104. At this time, the amount of first light received by the first light-receiving unit 224b changes from the amount of first light received by the first light-receiving unit 224b in the state shown in Figures 11(A) and 11(B).

[0119] On the other hand, at the timing shown in Figure 11(C), the pallet 104 passes along the optical axis of the second photoelectric sensor 226, and there are no obstructions along the optical axis of the second photoelectric sensor 226. Therefore, the second light emitted from the second light-emitting unit 226a is received by the second light-receiving unit 226b, which is horizontally opposed to it. Consequently, the amount of second light received by the second light-receiving unit 226b returns to the amount of second light received by the second light-receiving unit 226b in the state shown in Figure 11(A).

[0120] In the example shown in Figure 11(C), at the moment when the first light emitted from the first light-emitting unit 224a of the first photoelectric sensor 224 is blocked by the pallet 104, the second light emitted from the second light-emitting unit 226a of the second photoelectric sensor 226 is received by the second light-receiving unit 226b. However, depending on the tilt of the pallet 104, at the moment when the first light emitted from the first light-emitting unit 224a of the first photoelectric sensor 224 is blocked by the pallet 104, the second light emitted from the second light-emitting unit 226a of the second photoelectric sensor 226 may remain blocked by the pallet 104.

[0121] As the pallet 104 descends further and moves away from the optical axis of the first photoelectric sensor 224, as shown in Figure 11(D), the amount of first light received by the first light receiving unit 224b returns to the amount of first light received by the first light receiving unit 224b in the state shown in Figure 11(A).

[0122] A detection signal indicating the amount of first light received by the first light receiving unit 224b of the first photoelectric sensor 224, and a detection signal indicating the amount of second light received by the second light receiving unit 226b of the second photoelectric sensor 226, are output to the control unit 206 of the control device 200. Based on the received detection signals, the control unit 206 detects whether or not the pallet 104 is tilted in the front-to-back direction. Specifically, it determines whether or not the light output from the light emitting unit of the other photoelectric sensor will be blocked by the pallet 104 within a predetermined time from the moment when the light emitted from the light emitting unit of one of the two photoelectric sensors is blocked by the pallet 104.

[0123] The control unit 206 determines whether the second or first light is blocked by the pallet 104 within a predetermined time from the time when the first or second light is blocked by the pallet 104. If the second light is blocked within a predetermined time from the time when the first light is blocked by the pallet 104, or if the first light is blocked within a predetermined time from the time when the second light is blocked by the pallet 104, the control unit 206 determines that there is virtually no tilt of the pallet 104 in the front-rear direction and maintains the downward movement of the pallet 104. On the other hand, if the second light is not blocked by the pallet 104 within a predetermined time from the time when the first light is blocked by the pallet 104, or if the first light is not blocked by the pallet 104 within a predetermined time from the time when the second light is blocked by the pallet 104, the control unit 206 determines that the pallet 104 is tilted in the front-rear direction, generates an instruction signal to stop the downward movement of the pallet 104, and transmits it to the pallet drive unit 216.

[0124] As shown in Figure 11, when the pallet 104 is tilted downward from the rear to the front, the timing at which the second light emitted from the second light-emitting unit 226a of the second photoelectric sensor 226 is blocked by the pallet 104 is different from the timing at which the first light emitted from the first light-emitting unit 224a of the first photoelectric sensor 224 is blocked by the pallet 104. Based on the detection signal received from the second photoelectric sensor 226, the control unit 206 can determine whether or not the pallet 104 is tilted in the front-to-back direction by determining whether or not the first light is blocked by the pallet 104 within a predetermined time from the timing at which the second light is blocked by the pallet 104.

[0125] The predetermined time refers to a predetermined time range that serves as a criterion for determining whether or not the pallet 104 is tilted in the front-rear direction. The predetermined time can be set in advance by the manager of the parking device 100 based on the movement speed of the pallet 104. The predetermined time is stored in advance in the storage unit 204 of the control device 200. The predetermined time may be changed by the manager of the parking device 100. If the second light / first light is blocked within a predetermined time from the timing when the first light / second light is blocked by the pallet 104, the control unit 206 determines that there is substantially no tilt of the pallet 104 in the front-rear direction. Here, substantially no tilt of the pallet 104 in the front-rear direction includes not only the case where the pallet 104 is not tilted at all in the front-rear direction, but also the case where the pallet 104 is tilted slightly in the front-rear direction to the extent that there is no risk of damage to the pallet 104, the vehicle V placed on the pallet 104, the parking device 100A, etc., even if the pallet 104 continues to move up and down.

[0126] The upward and downward speeds of the pallet 104 may be different. If the upward and downward speeds of the pallet 104 are different, the predetermined time may include a predetermined time corresponding to the upward movement of the pallet 104 (first time) and a predetermined time corresponding to the downward movement of the pallet 104 (second time). In this embodiment, the downward speed of the pallet 104 may be faster than the upward speed of the pallet. In this case, the second time corresponding to the downward movement of the pallet 104 is shorter than the first time corresponding to the upward movement of the pallet 104. The control unit 206 determines whether the pallet 104 is moving upward or downward. If the pallet 104 is moving upward, the control unit 206 determines whether the second light / first light is blocked by the pallet 104 within one hour from the timing when the first light / second light is blocked by the pallet 104, and determines whether the pallet 104 is tilted in the front-rear direction. If the pallet 104 is moving downward, the control unit 206 determines within two hours from the time when the first light / second light is blocked by the pallet 104 whether or not the second light / first light is blocked by the pallet 104, and determines whether or not the pallet 104 is tilted in the front-back direction.

[0127] [Detection of pallet tilt in the front-to-back direction] As described above, the control unit 206 detects whether or not the pallet 104 is tilted in the front-to-back horizontal direction based on the detection signals output from the first photoelectric sensor 224 and the second photoelectric sensor 226, respectively.

[0128] Figure 12 is a flowchart illustrating the processing of the control unit 206 for detecting whether or not the pallet 104 is tilted in the front-rear direction in the parking device 100A according to this embodiment. In this embodiment, the explanation is based on the premise that the upward speed and downward speed of the pallet 104 are different.

[0129] When the operation of the parking device 100A is started, the control unit 206 checks whether the parking device 100A is in automatic operation mode (S1201). If the parking device 100A is in automatic operation mode (S1201; YES), the control unit 206 checks whether the pallet 104 is to be raised or lowered (S1202). On the other hand, if the parking device 100A is not in automatic operation mode (S1201; NO), the control unit 206 repeats the process of S1201 until it enters automatic operation mode. Here, cases where the parking device 100A is not in automatic operation mode include, for example, when the parking device 100A is in manual operation mode, or when it has stopped due to an error during automatic operation.

[0130] If the pallet 104 is to be moved upward, the process proceeds to S1203. If the pallet 104 is to be moved downward, the process proceeds to S1210. On the other hand, if the pallet 104 is neither being moved upward nor downward (S1202; NO), the control unit 206 repeats the process of S1202 until the pallet 104 is to be moved upward or downward. Here, cases where the pallet 104 is neither being moved upward nor downward include, for example, when the pallet 104 is being moved horizontally or when the gate 108 is being opened or closed.

[0131] When the pallet 104 is moved upward (S1202; upward movement operation), the control unit 206 obtains a predetermined time (first time) corresponding to the upward movement of the pallet 104 from the storage unit 204 (S1203).

[0132] Next, the control unit 206 determines whether or not the shielding of the first or second light has started by the pallet 104 (S1204). Based on the detection signal output from the first photoelectric sensor 224 indicating the amount of light received by the first light, or the detection signal output from the second photoelectric sensor 226 indicating the amount of light received by the second light, the control unit 206 determines whether or not the shielding of the first or second light (first light / second light) has started. If the shielding of the first / second light has started (S1204; YES), the control unit 206 starts the timer (S1205).

[0133] The control unit 206, while counting with a timer, checks whether the shielding of the second light or the first light (second light / first light) has started by the pallet 104 until the first time has elapsed. Specifically, if it is within the first time (S1206; YES), the control unit 206 determines, based on the detection signal, whether the shielding of the second light / first light has started by the pallet 104 (S1207). If the shielding of the second light / first light by the pallet 104 has started (S1207; YES), the control unit 206 stops the timer (S1208) and terminates the process.

[0134] On the other hand, if shielding of the second light / first light by the pallet 104 does not begin (S1207; NO), the control unit 206 repeats the process of S1207 until the first time has elapsed.

[0135] If the shielding of the second / first light by the pallet 104 does not begin after 1 hour has elapsed, that is, if the shielding of the second / first light by the pallet 104 does not begin within 1 hour (S1206; NO), the control unit 206 determines that the pallet 104 is tilted in the front-rear direction, outputs a stop instruction signal to stop the upward movement of the pallet 104 (S1209), and terminates the process. The outputted stop instruction signal is transmitted to the pallet drive unit 216.

[0136] When the pallet 104 is moved downwards (S1202; downward movement operation), the control unit 206 obtains a predetermined time (second time) corresponding to the downward movement of the pallet 104 from the storage unit 204 (S1210).

[0137] Next, the control unit 206 determines whether or not the shielding of the first or second light has started by the pallet 104 (S1211). Based on the detection signal output from the first photoelectric sensor 224 indicating the amount of light received by the first light, or the detection signal output from the second photoelectric sensor 226 indicating the amount of light received by the second light, the control unit 206 determines whether or not the shielding of the first or second light (first light / second light) has started. If the shielding of the first / second light has started (S1211; YES), the control unit 206 starts the timer (S1212).

[0138] The control unit 206, while counting with a timer, checks whether the shielding of the second or first light (second light / first light) is initiated by the pallet 104 until the second time has elapsed. Specifically, if it is within the second time (S1213; YES), the control unit 206 determines, based on the detection signal, whether the shielding of the second / first light has been initiated by the pallet 104 (S1214). If the shielding of the second / first light by the pallet 104 has been initiated (S1214; YES), the control unit 206 stops the timer (S1215) and terminates the process.

[0139] On the other hand, if shielding of the second / first light by the pallet 104 does not begin (S1213; NO), the control unit 206 repeats the process of S1214 until the second time has elapsed.

[0140] If the shielding of the second / first light by the pallet 104 does not begin after two hours, that is, if the shielding of the second / first light by the pallet 104 does not begin within two hours (S1213; NO), the control unit 206 determines that the pallet 104 is tilted in the front-rear direction, outputs a stop instruction signal to stop the downward movement of the pallet 104 (S1209), and terminates the process. The outputted stop instruction signal is transmitted to the pallet drive unit 216.

[0141] The above describes the flow for the control unit 206 to detect whether or not the pallet 104 is tilted in the front-rear direction in the parking device 100A according to this embodiment. However, the flow according to this embodiment is not limited to the flow described with reference to Figure 12.

[0142] For example, if the upward and downward speeds of the pallet 104 are the same, the control unit 206 may, instead of acquiring the first time or the second time, acquire a predetermined time common to the upward and downward movement of the pallet 104 from the storage unit 204. In this case, when the blocking of the first or second light begins, the control unit 206 checks whether the blocking of the second or first light by the pallet 104 has begun until the timer has elapsed the predetermined time.

[0143] In this embodiment, the presence or absence of tilt in the pallet 104 is determined based on the timing at which the blocking of the first or second light begins. In other words, since there is no need to wait for detection signals to be output from both the first photoelectric sensor 224 and the second photoelectric sensor 226, the presence or absence of tilt in the pallet 104 can be detected quickly.

[0144] <Third Embodiment> In the second embodiment described above, the detection of the tilt of the pallet 104 in the front-rear direction was explained using a first photoelectric sensor 224 and a second photoelectric sensor 226 having optical axes parallel to each other. In this embodiment, the detection of the tilt of the pallet 104 in the front-rear direction will be explained using a photoelectric sensor having optical axes parallel to the longitudinal direction of the pallet 104.

[0145] [Configuration of parking system 100B] Figure 13 is a schematic side view showing the configuration of the parking device 100B according to this embodiment. Figure 14 is a schematic front view showing the configuration of the parking device 100B according to this embodiment. Figures 13 and 14 show the main configuration of the parking device 100B according to this embodiment.

[0146] Parking device 100B according to one embodiment of this disclosure has the same configuration as parking device 100 according to the first embodiment described with reference to Figures 1 and 2, except for the installation position of the first photoelectric sensor 224. Therefore, the following description will mainly focus on the installation position of the first photoelectric sensor 224, and detailed descriptions of other components will be omitted.

[0147] The first light-emitting unit 224a and the first light-receiving unit 224b of the first photoelectric sensor 224 are positioned such that the pallet 104 blocks the first light emitted from the first light-emitting unit 224a within a portion of the pallet 104's movement range (up and down range). In other words, the first photoelectric sensor 224 is installed at a stationary position outside the pallet 104's movement range (up and down range) such that its optical axis overlaps with the pallet 104's movement range (up and down range).

[0148] In the parking device 100B according to this embodiment, for example, as shown in Figures 13 and 14, the first photoelectric sensor 224 may be installed on a beam 103 that spans between adjacent support columns 102 in the left-right direction (horizontal direction). In other words, in this embodiment, the first photoelectric sensor 224 is installed so as to have an optical axis parallel to the longitudinal direction of the pallet 104, that is, the front-rear direction of the parking device 100B. The installation position of the first photoelectric sensor 224 is not limited to the beam 103, but may also be installed on the support columns 102. Furthermore, if the parking device 100B has an outer wall, the first photoelectric sensor 224 may be installed on the outer wall.

[0149] Figures 13 and 14 show, as an example, a case in which the first light-emitting unit 224a of the first photoelectric sensor 224 is installed on the front side of the parking device 100B where the entrance / exit is located, and the first light-receiving unit 224b of the first photoelectric sensor 224 is installed on the rear side opposite in the front-to-back direction. However, in this embodiment, the arrangement of the first photoelectric sensor 224 is not limited to this, and the first light-receiving unit 224b may be installed on the front side of the parking device 100B, and the first light-emitting unit 224a may be installed on the rear side opposite in the front-to-back direction.

[0150] As described above, the first photoelectric sensor 224 is positioned such that the pallet 104 shields the first light emitted from the first light-emitting unit 224a within a portion of the pallet 104's movement range (lifting range). Preferably, the first photoelectric sensor 224 is installed in a position where the first light emitted from the first light-emitting unit 224a is not shielded by the vehicle V placed on the pallet 104. In other words, it is preferable that the body of the vehicle V placed on the pallet 104 does not enter the optical axis of the first photoelectric sensor 224 during the lifting and lowering operation of the pallet 104. In order to detect the tilt of the pallet 104 when it is lifted or lowered, the time (first shielding time) during which the first light emitted from the first light-emitting unit 224a of the first photoelectric sensor 224 is shielded by the pallet 104 is detected. If the body of vehicle V blocks the light emitted from the first light-emitting unit 224a (first light), the time during which the first light is blocked by the pallet 104 (first blocking time) may be incorrectly detected, potentially causing a malfunction in the parking device 100. Therefore, by installing the first photoelectric sensor 224 in a position where the first light emitted from the first light-emitting unit 224a is not blocked by the vehicle V placed on the pallet 104, the accuracy of detecting the tilt of the pallet 104 can be improved.

[0151] In this embodiment, the first photoelectric sensor 224 is installed at a position corresponding to one of the horizontal ends of the pallet 104, such that the vehicle body of the vehicle V placed on the pallet 104 does not enter the optical axis of the first photoelectric sensor 224 during the lifting and lowering operation of the pallet 104.

[0152] The schematic configuration of the parking device 100B according to this embodiment is substantially the same as the schematic configuration of the parking device 100 according to the first embodiment shown with reference to Figure 3, so redundant explanations will be omitted.

[0153] Figures 15 and 16 illustrate how the first light emitted from the first light-emitting section 224a of the first photoelectric sensor 224 is blocked by the pallet 104. As an example, Figures 15 and 16 illustrate a case in which the first photoelectric sensor 224, installed on a beam 103 (not shown) that spans between adjacent support columns 102 in the left-right direction (horizontal direction), detects the tilt of the pallet 104 in the front-rear direction when the pallet 104 is lowered.

[0154] Figure 15 illustrates how the first light emitted from the first light-emitting section 224a of the first photoelectric sensor 224 is blocked by the pallet 104 when the pallet 104 is not tilted in the front-to-back direction.

[0155] As shown in Figure 15(A), if there is no obstruction on the optical axis between the first light-emitting unit 224a and the first light-receiving unit 224b, the first light emitted from the first light-emitting unit 224a is received by the first light-receiving unit 224b.

[0156] As shown in Figure 15(B), when the pallet 104 descends and enters the optical axis between the first light-emitting unit 224a and the first light-receiving unit 224b, the first light emitted from the first light-emitting unit 224a is blocked by the pallet 104. At this time, the amount of first light received by the first light-receiving unit 224b changes from the amount of first light received by the first light-receiving unit 224b in the state shown in Figure 15(A).

[0157] As the palette 104 descends further and moves away from the optical axis between the first light-emitting unit 224a and the first light-receiving unit 224b, as shown in Figure 15(C), the amount of first light received by the first light-receiving unit 224b returns to the amount of first light received by the first light-receiving unit 224b in the state shown in Figure 15(A).

[0158] Figure 16 illustrates how the first light emitted from the first light-emitting section 224a of the first photoelectric sensor 224 is blocked by the pallet 104 when the pallet 104 is tilted in the front-to-back direction.

[0159] As shown in Figure 16(A), if there is no obstruction on the optical axis between the first light-emitting unit 224a and the first light-receiving unit 224b, the first light emitted from the first light-emitting unit 224a is received by the first light-receiving unit 224b.

[0160] As shown in Figure 16(B), when the pallet 104 descends and enters the optical axis between the first light-emitting unit 224a and the first light-receiving unit 224b, the first light emitted from the first light-emitting unit 224a is blocked by the pallet 104. At this time, the amount of first light received by the first light-receiving unit 224b changes from the amount of first light received by the first light-receiving unit 224b in the state shown in Figure 16(A).

[0161] As shown in Figure 16(C), when the pallet 104 is tilted, even if the pallet 104 descends further, the pallet 104 remains on the optical axis between the first light-emitting unit 224a and the first light-receiving unit 224b, and the first light emitted from the first light-emitting unit 224a is blocked by the pallet 104. At this time, the amount of first light received by the first light-receiving unit 224b is approximately the same as the amount of first light received by the first light-receiving unit 224b in the state shown in Figure 16(B).

[0162] As the palette 104 descends further and moves away from the optical axis between the first light-emitting unit 224a and the first light-receiving unit 224b, as shown in Figure 16(D), the amount of first light received by the first light-receiving unit 224b returns to the amount of first light received by the first light-receiving unit 224b in the state shown in Figure 16(A).

[0163] A detection signal indicating the amount of first light received by the first light receiving unit 224b of the first photoelectric sensor 224 is output to the control unit 206 of the control device 200. Based on the received detection signal, the control unit 206 determines whether the shielding time of the first light by the pallet 104 (first shielding time) has reached a predetermined reference time. If the first shielding time has not reached the predetermined reference time, that is, if the first shielding time is less than the predetermined reference time, the control unit 206 determines that there is no tilting of the pallet 104 in the front-rear direction and maintains the downward movement of the pallet 104. On the other hand, if the first shielding time has reached the predetermined reference time, that is, if the first shielding time is equal to or greater than the predetermined reference time, the control unit 206 determines that the pallet 104 is tilted in the front-rear direction and generates an instruction signal to stop the downward movement of the pallet 104 and transmits it to the pallet drive device 216.

[0164] As shown in Figure 16, when the pallet 104 is tilted in the front-to-back direction, the time that the pallet 104 is on the optical axis between the first light-emitting unit 224a and the first light-receiving unit 224b is longer than when the pallet 104 is not tilted in the front-to-back direction, as shown in Figure 15. In other words, when the pallet 104 is tilted in the front-to-back direction, the first shielding time during which the pallet 104 shields the first light traveling from the first light-emitting unit 224a to the first light-receiving unit 224b is longer than the first shielding time when the pallet 104 is not tilted in the front-to-back direction. Therefore, by pre-determining a predetermined reference time and determining whether the first shielding time is less than the predetermined reference time or greater than or equal to the predetermined reference time, it is possible to determine whether the pallet 104 is tilted in the front-to-back direction.

[0165] The predetermined reference time can be set in advance by the administrator of the parking device 100 based on the movement speed of the pallet 104. The predetermined reference time is stored in advance in the memory unit 204 of the control device 200. The predetermined reference time may be changed by the administrator of the parking device 100. Note that the predetermined reference time in this embodiment may differ from the predetermined reference time in the first embodiment.

[0166] The upward and downward speeds of the pallet 104 may be different. If the upward and downward speeds of the pallet 104 are different, the predetermined reference time may include a reference time corresponding to the upward movement of the pallet 104 (first reference time) and a reference time corresponding to the downward movement of the pallet 104 (second reference time). In this embodiment, the downward speed of the pallet 104 may be faster than the upward speed of the pallet. In this case, the second reference time corresponding to the downward movement of the pallet 104 is shorter than the first reference time corresponding to the upward movement of the pallet 104. The control unit 206 determines whether the pallet 104 is moving upward or downward. If the pallet 104 is moving upward, the control unit 206 determines whether the first shielding time has reached the first reference time corresponding to the upward movement of the pallet 104, in other words, whether the first shielding time is less than the first reference time or is equal to or greater than the first reference time, and determines whether the pallet 104 is tilted in the front-rear direction. When the pallet 104 is moving downward, the control unit 206 determines whether the first shielding time has reached the second reference time corresponding to the downward movement of the pallet 104, in other words, whether the first shielding time is less than the second reference time or is equal to or greater than the second reference time, and then determines whether or not the pallet 104 is tilted in the front-to-back direction.

[0167] The processing flow for detecting whether or not the pallet 104 is tilted in the front-rear direction, based on the detection signal output from the first photoelectric sensor 224, by the control unit 206 of the parking device 100B according to this embodiment, is substantially the same as the processing for detecting whether or not the pallet 104 is tilted in the horizontal direction, based on the detection signal output from the first photoelectric sensor 224, as explained with reference to Figure 6. Therefore, redundant explanations will be omitted.

[0168] <Variation> The following describes some modified examples of the parking apparatus described herein.

[0169] [Example 1] The configurations of the first and second embodiments described above may be combined. Specifically, in the configuration of the parking device 100A according to the second embodiment, both detection of the horizontal tilt of the pallet 104 as described in the first embodiment and detection of the front-rear tilt of the pallet 104 as described in the second embodiment may be performed. The first photoelectric sensor 224 may be used in combination for detecting the horizontal tilt and the front-rear tilt.

[0170] In this case, even if the first shielding time during which the first light emitted from the first light-emitting unit 224a of the first photoelectric sensor 224 is shielded by the pallet 104 has not reached a predetermined reference time, if the second light is not shielded by the pallet 104 within a predetermined time from the timing when the first light is shielded by the pallet 104, or if the first light is not shielded by the pallet 104 within a predetermined time from the timing when the second light is shielded by the pallet 104, the control unit 206 generates an instruction signal to stop the vertical movement of the pallet 104 and transmits it to the pallet drive unit 216. The second photoelectric sensor 226 may be used in conjunction with the first photoelectric sensor 224 for detecting horizontal tilt and vertical tilt. Furthermore, both the first photoelectric sensor 224 and the second photoelectric sensor 226 may be used in conjunction with the first photoelectric sensor 224 for detecting horizontal tilt and vertical tilt.

[0171] [Differentiation 2] The configuration of the first embodiment and the third embodiment described above may be combined. Specifically, in the parking device 100 according to the first embodiment, the horizontal tilt of the pallet 104 may be detected by a photoelectric sensor installed so as to have an optical axis in the left-right direction (horizontal direction) perpendicular to the front-rear direction, and in the parking device 100B according to the third embodiment, the front-rear tilt of the pallet 104 may be detected by a photoelectric sensor installed so as to have an optical axis parallel to the front-rear direction.

[0172] In this case, even if the shielding time for light emitted from the light-emitting unit of one photoelectric sensor that is blocked by the pallet 104 has not reached a predetermined reference time, if the shielding time for light emitted from the light-emitting unit of the other photoelectric sensor that is blocked by the pallet 104 has reached a predetermined reference time, the control unit 206 generates an instruction signal to stop the vertical movement of the pallet 104 and transmits it to the pallet drive device 216.

[0173] [Difference 3] The first to third embodiments described above describe the detection of the tilt of the pallet 104 during upward and downward movement. However, the tilt of the pallet 104 may be detected during either upward or downward movement. Whether or not to detect the tilt of the pallet 104 during upward and / or downward movement may be set by the parking system administrator.

[0174] [Differentiation Example 4] In the first to third embodiments described above, a through-type photoelectric sensor using a laser, visible light, infrared light, etc., was given as an example of a sensor for detecting the tilt of the pallet 104. However, the sensor for detecting the tilt of the pallet 104 is not limited to a through-type photoelectric sensor.

[0175] For example, a reflective photoelectric sensor can be used as a sensor to detect the tilt of the pallet 104. In this case, a reflective material is provided on the surface of the pallet 104. Light emitted from the light-emitting part of the photoelectric sensor is reflected by the reflective material provided on the pallet 104, and the reflected light is received by the light-receiving part of the photoelectric sensor. Based on the time and timing of receiving the reflected light, it is possible to detect whether the pallet 104 is tilted horizontally and tilted in the front-to-back direction.

[0176] Furthermore, when using a reflective photoelectric sensor, one or more reflective mirrors may be provided outside the pallet's movement range. In this case, the light emitted from the light-emitting part of the photoelectric sensor may have its optical path altered by the reflective mirrors. The light-receiving part of the photoelectric sensor receives the light reflected by the reflective mirrors. By adjusting the installation position of the reflective mirrors, a single photoelectric sensor can detect both the horizontal and front-to-back tilt of the pallet.

[0177] Figure 17 is a diagram illustrating an example of the placement of a reflective photoelectric sensor. In Figure 17, a reflective photoelectric sensor 1701 is used to determine whether or not the pallet 104 is tilted horizontally and in the front-to-back direction. The photoelectric sensor 1701 has a light-emitting section 1701a and a light-receiving section 1701b. In the example shown in Figure 17, the light-emitting section 1701a of the photoelectric sensor 1701 is installed so as to have an optical axis parallel to the longitudinal direction of the pallet 104. The light-emitting section 1701a is positioned such that the pallet 104 blocks the light emitted from the light-emitting section 1701a in a portion of the pallet 104's movement range (lifting range). In other words, the light-emitting section 1701a is installed at a stationary position outside the pallet 104's movement range (lifting range) so that its optical axis overlaps with the pallet 104's movement range (lifting range).

[0178] A first reflective mirror 1710 is installed opposite the light-emitting section 1701a of the photoelectric sensor 1701, across the pallet 104. The first reflective mirror 1710 is installed on the optical axis of the light-emitting section 1701a of the photoelectric sensor 1701. Light emitted from the light-emitting section 1701a of the photoelectric sensor 1701 is reflected by the first reflective mirror 1710 and incident on the second reflective mirror 1720.

[0179] The second reflective mirror 1720 is positioned on the optical axis of the first reflective mirror 1710. The second reflective mirror 1720 further reflects the light reflected by the first reflective mirror 1710. The light reflected by the second reflective mirror 1720 is received by the light receiving section 1701b of the photoelectric sensor 1701. In Figure 17, the second reflective mirror 1720 is positioned so that the optical axis of the light reflected by the second reflective mirror 1720 is parallel to the left-right direction (horizontal direction) of the pallet 104.

[0180] The light-receiving unit 1701b of the photoelectric sensor 1701 is installed on the optical axis of the second reflective mirror 1720 and receives light reflected by the second reflective mirror 1720. The light-receiving unit 1701b is installed at a stationary position outside the movement range (lifting range) of the pallet 104, such that the pallet 104 blocks the light reflected from the second reflective mirror 1720 within a portion of the pallet 104's movement range (lifting range).

[0181] Figure 18 illustrates another example of the placement of a reflective photoelectric sensor. In Figure 18, a reflective photoelectric sensor 1801 is used to determine whether the pallet 104 is tilted horizontally and in the front-to-back direction. The photoelectric sensor 1801 has a light-emitting section 1801a and a light-receiving section 1801b. In the example shown in Figure 18, the light-emitting section 1801a of the photoelectric sensor 1801 is installed so that it has an optical axis parallel to the left-to-right direction (horizontal direction) of the pallet 104. The light-emitting section 1801a is positioned so that the pallet 104 blocks the light emitted from the light-emitting section 1801a in a portion of the pallet 104's movement range (lifting range). In other words, the light-emitting section 1801a is installed at a stationary position outside the pallet 104's movement range (lifting range) so that its optical axis overlaps with the pallet 104's movement range (lifting range).

[0182] A first reflective mirror 1810 is installed opposite the light-emitting section 1801a of the photoelectric sensor 1801, across the pallet 104. The first reflective mirror 1810 is installed on the optical axis of the light-emitting section 1801a of the photoelectric sensor 1801. Light emitted from the light-emitting section 1801a of the photoelectric sensor 1801 is reflected by the first reflective mirror 1810. In Figure 18, the first reflective mirror 1810 is installed so that the optical axis of the light reflected by the first reflective mirror 1810 is parallel to the longitudinal direction of the pallet 104. The light reflected by the first reflective mirror 1810 is incident on the second reflective mirror 1820.

[0183] The second reflective mirror 1820 is positioned on the optical axis of the first reflective mirror 1810. The second reflective mirror 1820 further reflects the light reflected by the first reflective mirror 1810. The light reflected by the second reflective mirror 1820 is received by the light receiving section 1801b of the photoelectric sensor 1801. In Figure 18, the second reflective mirror 1820 is positioned so that the optical axis of the light reflected by the second reflective mirror 1820 is parallel to the left-right direction (horizontal direction) of the pallet 104.

[0184] The light-receiving unit 1801b of the photoelectric sensor 1801 is installed on the optical axis of the second reflecting mirror 1820 and receives light reflected by the second reflecting mirror 1820. The light-receiving unit 1801b is installed at a stationary position outside the movement range (lifting range) of the pallet 104, such that the pallet 104 blocks the light reflected from the second reflecting mirror 1820 within a portion of the pallet 104's movement range (lifting range).

[0185] In the examples shown in Figures 17 and 18, a single photoelectric sensor 1701, 1801 can detect both the horizontal and longitudinal tilt of the pallet.

[0186] Furthermore, a gyro sensor may be provided on the pallet 104 itself to detect its tilt. Alternatively, a limit switch may be provided on the pallet 104 itself to detect physical contact. In addition, a camera can be installed to detect the tilt of the pallet 104 through image recognition.

[0187] [Difference 5] In the parking device 100A of the second embodiment described with reference to Figures 7 and 8, both the first photoelectric sensor 224 and the second photoelectric sensor 226 are provided on a beam 103 that is installed between the support columns 102. However, the two photoelectric sensors 224 and 226 may be installed in different positions. In this case, the first photoelectric sensor 224 and the second photoelectric sensor 226 may be installed in positions that are offset from each other in the vertical direction.

[0188] If the first photoelectric sensor 224 and the second photoelectric sensor 226 are installed in positions offset from each other in the vertical direction, even if the pallet 104 is not tilted in the front-to-back direction, the light emitted from the light-emitting part of the other photoelectric sensor may not be blocked by the pallet 104 within a predetermined time frame from the moment when the light emitted from the light-emitting part of one photoelectric sensor is blocked by the pallet 104. In this case, the control unit 206 can determine whether or not the pallet 104 is tilted in the front-to-back direction by pre-incorporating an offset time based on the vertical offset (distance) between the installation position of the first photoelectric sensor 224 and the installation position of the second photoelectric sensor 226 and the movement speed of the pallet 104 into a predetermined time frame.

[0189] [Modification 6] In the first to third embodiments described above, the case of detecting the inclination of the pallet 104 within the movement range (lifting range) of the pallet 104 was described. However, the inclination of the pallet 104 at the fixed position of the pallet corresponding to each level of the parking device 100, 100A, and 100B may also be detected by a photoelectric sensor.

[0190] For example, one or more photoelectric sensors can be installed at positions corresponding to the fixed positions of the pallets corresponding to each level of the parking devices 100, 100A, and 100B. The positions where the photoelectric sensors are installed are not particularly limited, as long as the light emitted from the light-emitting part toward the light-receiving part of the photoelectric sensor is shielded by the pallet 104 at the fixed positions of the pallets corresponding to each level of the parking devices 100, 100A, and 100B.

[0191] For example, similar to the first embodiment described above, a pair of photoelectric sensors may be installed at fixed positions of the pallets corresponding to each level of the parking devices 100, 100A, and 100B, such that the optical axis is perpendicular to the longitudinal direction of the pallet 104. This makes it possible to detect the tilt in the left-right direction (horizontal direction) at fixed positions of the pallets on each level.

[0192] Furthermore, similar to the second embodiment described above, two pairs of photoelectric sensors may be installed at fixed positions on the pallets corresponding to each level of the parking device 100, 100A, and 100B, such that their optical axes are perpendicular to the longitudinal direction (front-to-back direction) of the pallet 104. This makes it possible to detect the tilt in the front-to-back direction at the fixed position of the pallet on each level. In addition, as described in Modification 1 above, by using at least one of the two pairs of photoelectric sensors to detect the tilt in the horizontal direction in addition to detecting the tilt in the front-to-back direction, it is possible to detect the tilt in both the horizontal and front-to-back directions at the fixed position of the pallet on each level.

[0193] Furthermore, similar to the third embodiment described above, a pair of photoelectric sensors may be installed at fixed positions on the pallets corresponding to each level of the parking devices 100, 100A, and 100B, such that their optical axes are parallel to the longitudinal direction of the pallet 104. This makes it possible to detect the forward and backward tilt of the pallets at fixed positions on each level.

[0194] Furthermore, as described in Modification 2 above, a pair of photoelectric sensors may be installed so as to have optical axes perpendicular to the longitudinal direction (front-to-back direction) of the pallet 104, and another pair of photoelectric sensors may be installed so as to have optical axes parallel to the front-to-back direction. This makes it possible to detect the horizontal and front-to-back tilt of the pallets at their fixed positions on each level.

[0195] As described above, when the control unit 206 detects tilting of the pallet 104 at the fixed position of each level of the parking devices 100, 100A, and 100B, it generates an instruction signal to stop the lifting and traversing movements of the pallet 104 and transmits it to the pallet drive unit 216. This prevents damage to the pallet, the vehicle placed on the pallet, or the parking device not only when the pallet 104 is lifting or moving, but also when it is moving traversing.

[0196] The embodiments described above as one embodiment of this disclosure can be combined and implemented as appropriate, insofar as they do not contradict each other. Furthermore, any configurations based on the embodiments shown, with additions, deletions, or design changes made by those skilled in the art, or with additions, omissions, or changes in processes, are also included in the scope of the invention, as long as they retain the gist of this disclosure.

[0197] Any effects or benefits other than those brought about by the embodiments described above, if they are clear from the description herein or easily predictable to a person skilled in the art, are naturally considered to be brought about by the present invention. [Explanation of Symbols]

[0198] 100, 100A, 100B... Parking system 102...post 103...beam 104...Palette 106... Elevator 108...Gate 200... Control device 204...Storage section 206... Control Unit 214...Operation panel 216...Pallet drive unit 218...Gate drive unit 220... Sensor 222... News Department 224...First photoelectric sensor 226...Second photoelectric sensor

Claims

[Claim 1] A pallet on which a vehicle can be placed, A pallet drive unit for raising and lowering the pallet, A first photoelectric sensor includes a first light-emitting unit and a first light-receiving unit that receives first light from the first light-emitting unit, and is positioned such that the pallet shields the first light in a portion of the pallet's movement range. When the first shielding time during which the first light is shielded by the palette reaches a predetermined reference time, a control unit executes a predetermined control, A parking device equipped with the following features.

Images