Tank car

Abstract

To provide a tank car which includes a movable handrail and effectively prevents a worker from climbing a tank in a state that the handrail is not erected with a simple structure.SOLUTION: A tank car includes: a tank 20 mounted on a vehicle; a ladder 30 for enabling a worker to climb the tank 20; a handrail 40 which is provided at the upper surface side of the tank 20 and may be changed to an erection state and a non-erection state; a handrail operation switch 80 which is used in an operation for bringing the handrail 40 into the erection state or the non-erection state; blocking means 50 which may be changed to a blocking state that the blocking means 50 blocks a path of the ladder 30 and a non-blocking state that the blocking means 50 does not block the path; and detecting means 60 which detects the erection state and the non-erection state of the handrail 40. The blocking means 50 has a blocking fixing part 53 which fixes the blocking state. It is not possible to release fixture by the blocking fixing part 53 when the detecting means 60 detects the handrail 40 being in the non-erection state.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a tank vehicle equipped with a tank, such as a high-altitude water washing vehicle, a tank truck, or a sludge suction vehicle. [Background technology]

[0002] High-altitude water washers are capable of spraying water at high altitudes and over a wide area, and are therefore used in steel mills and other facilities to remove deposits and suppress dust. High-altitude water washers are equipped with a water tank, and since workers performing maintenance, cleaning, and water supply may climb into the water tank, handrails (safety fences) are installed on the left and right sides of the top of the water tank to prevent falls. Handrails are also sometimes installed on the top of the tanks of other tank vehicles, such as tank trucks, sprinkler trucks, and sludge suction trucks. For example, Patent Document 1 discloses a vehicle safety fence that has a fence height change structure that, when in use, has a fence height that ensures the safety of workers and, when not in use, has a lower fence height; the fence height change structure is composed of a folding mechanism that collapses the fence body, an extension mechanism that extends and contracts the fence body along the fence height direction, or a detachable mechanism that detachably attaches the fence body. Furthermore, Patent Document 2 discloses a tank car in which a protective frame is erected on a work platform above the tank so that it can be moved between two positions, an upright position and a tilted position, while a link mechanism that moves the protective frame between the two positions is connected to the protective frame, extends downward from the work platform, and is provided so that it can be operated from below the tank. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2000-326784 [Patent Document 2] Japanese Patent Application Laid-Open No. 2002-308005 Summary of the Invention [Problem to be solved by the invention]

[0004] Even if a tanker truck has handrails to prevent falls, if the handrails are movable and are not securely in an upright position when a worker is on top of the water tank, there is a risk that the worker may fall. Here, in Patent Document 1, workers can climb onto the tank even when the safety fence is not erected. In addition, Patent Document 2 aims to prevent forgetting to raise the protective frame by rotating the rotating ladder section to put the ladder in a usable or unused state, and by linking the usable or unusable state of the ladder with the upright or tilted state of the protective frame; however, the configuration is complex and the cost is high. Therefore, the present invention aims to effectively prevent, with a simple configuration, the unsafe behavior of workers climbing onto a tank when the handrails are not installed in a tank car equipped with movable handrails. [Means for solving the problem]

[0005] The tank car 1 of the present invention described in claim 1 comprises a tank 20 mounted on the vehicle, a ladder 30 for climbing up to the tank 20, a handrail 40 provided on the upper surface of the tank 20 and changeable between an upright state and a non-upright state, a handrail operation switch 80 used to operate the handrail 40 to be in an upright state or a non-upright state, an obstruction means 50 changeable between an obstruction state that blocks the path of the ladder 30 and a non-obstruction state that does not block the path, and a detection means 60 that detects the upright state and the non-upright state of the handrail 40, wherein the obstruction means 50 has an obstruction fixing part 53 that fixes the obstruction state, and the fixation by the obstruction fixing part 53 cannot be released when the detection means 60 detects that the handrail 40 is in a non-upright state.

[0006] The present invention described in claim 2 is characterized in that, in the tank car 1 described in claim 1, when the obstructing means 50 is not in an obstructing state, the operation of placing the handrail 40 in a non-upright state using the handrail operating switch 80 is invalid.

[0007] The present invention described in claim 3 is characterized in that, in the tank car 1 described in claim 2, it is provided with a non-standing state operation prevention switch 100 that disables the operation of placing the handrail 40 in a non-standing state, among the operations using the handrail operation switch 80.

[0008] The present invention described in claim 4 is characterized in that, in the tank car 1 described in any one of claims 1 to 3, the obstruction means 50 has a main body portion 51 having a length greater than or equal to the width of the ladder 30, and a base end support portion 52 provided on one side of the ladder 30 and supporting the base end of the main body portion 51, and the main body portion 51 is oriented horizontally so that its tip is positioned on the other side of the ladder 30, thereby blocking the path of the ladder 30 and thereby entering an obstruction state.

[0009] The present invention as set forth in claim 5 is characterized in that in the tank car 1 as set forth in claim 4, the main body 51 is oriented horizontally at a height between the first and second steps of the ladder 30.

[0010] The present invention as set forth in claim 6 is characterized in that in the tank car 1 as set forth in claim 4 or claim 5, the main body 51 is a hard rod-shaped member.

[0011] The present invention described in claim 7 is characterized in that, in the tank car 1 described in claim 6, the main body 51 is rotatable up and down around the base end support part 52 as an axis, and the obstruction means 50 is placed in a non-obstructing state by rotating the main body 51 upward to a vertical orientation, and in a obstructing state by rotating the main body 51 downward to a horizontal orientation. [Effects of the Invention]

[0012] According to the present invention, in a tank car equipped with movable handrails, the unsafe behavior of workers climbing onto the tank when the handrails are not installed can be effectively prevented with a simple configuration. [Brief explanation of the drawings]

[0013] [Figure 1] FIG. 1 is a left side view of a tank car according to an embodiment of the present invention. [Figure 2]FIG. 10 is a diagram showing the periphery of the location where the inhibiting means is provided. [Figure 3] FIG. 10 is a diagram showing the periphery of the location where the inhibiting means is provided. [Figure 4] FIG. 10 is a diagram showing a control flow of the control means for the obstruction fixing unit. [Figure 5] The figure shows the main flow of control for the up and down movement of the handrail. [Figure 6] FIG. 10 is a diagram showing a flow of the handrail up / down operation process based on the handrail upper limit position. [Figure 7] FIG. 10 is a diagram showing a flow of the handrail up / down operation process based on the handrail lower limit position. [Figure 8] FIG. 10 is a diagram showing a flow of the handrail up / down operation process based on the handrail midway position. DETAILED DESCRIPTION OF THE INVENTION

[0014] A tank car according to a first embodiment of the present invention comprises: A tank mounted on the vehicle; A ladder to climb onto the tank, A handrail provided on the upper surface side of the tank and changeable between an upright state and a non-upright state; A handrail operation switch used to operate the handrail to be in an upright state or a non-upright state; an obstructing means that can be changed between an obstructing state that obstructs the ladder path and a non-obstructing state that does not obstruct the path; A detection means for detecting whether the handrail is in an upright position or a non-upright position, a control means for determining a detection result by the detection means; Equipped with The inhibiting means has an inhibiting fixing part that fixes the inhibited state, When the control means determines from the detection result of the detection means that the handrail is in a non-standing state, Fixation by the inhibitory fixation part maintain This is what we do. According to this embodiment, in a tank car equipped with movable handrails, workers can be effectively prevented from climbing onto the tank when the handrails are not installed.

[0015] In the second embodiment of the present invention, in a tank car according to the first embodiment, when the obstructing means is not in an obstructing state, the operation of placing the handrail in a non-upright state using the handrail operating switch is invalid. According to this embodiment, the handrails can be maintained in an upright state when an operator is on the tank, thereby improving safety.

[0016] The third embodiment of the present invention is a tank car according to the second embodiment, which is equipped with a non-standing state operation prevention switch that disables the operation of placing the handrail in a non-standing state, among the operations using the handrail operation switch. According to this embodiment, it is possible to prevent other workers on the ground from accidentally lowering the handrail when there is a worker on the tank.

[0017] In a fourth embodiment of the present invention, in a tank car according to any one of the first to third embodiments, the obstruction means has a main body portion having a length greater than the width of the ladder and a base end support portion provided on one side of the ladder and supporting the base end of the main body portion, and the main body portion is oriented horizontally so that its tip is located on the other side of the ladder, thereby blocking the ladder's path and creating an obstruction state. According to this embodiment, the ladder path can be effectively blocked with a simple configuration.

[0018] A fifth embodiment of the present invention is a tank car according to the fourth embodiment, wherein the main body is oriented horizontally at a height between the first and second steps of the ladder. According to this embodiment, it becomes easier for the worker to recognize that the obstructing means is in the obstructing state before climbing the ladder.

[0019] A sixth embodiment of the present invention is a tank car according to the fourth or fifth embodiment, in which the main body is a hard rod-shaped member. According to this embodiment, even with a relatively simple configuration, it is possible to effectively prevent workers from climbing the ladder by avoiding the main body of the obstructing means that is in an obstructing state.

[0020] The seventh embodiment of the present invention is a tank car according to the sixth embodiment, in which the main body can be rotated up and down around the base end support part as an axis, and the obstruction means is configured to be in a non-obstructing state by rotating the main body upward to a vertical orientation, and to be in an obstructing state by rotating the main body downward to a horizontal orientation. According to this embodiment, it is possible to easily and quickly switch between the blocked state and the non-blocked state. [Example]

[0021] A tank car according to one embodiment of the present invention will now be described. FIG. 1 is a left side view of a tank car according to this embodiment. The tank car 1 in this embodiment is a high-altitude water washing vehicle used to remove deposits and suppress dust at high altitudes in steelworks, etc. The tank car 1 is equipped with an engine separate from the vehicle engine for driving, and can operate a water pump while driving to spray water in the front-to-rear and / or side directions of the vehicle, and can also use the truck crane installed on it to clean high altitudes. The tank car 1 comprises a cab (cabin) 10 provided at the front of the vehicle body, a tank 20 provided behind the cab 10, a ladder 30 provided with a handle and steps, a retractable handrail (safety fence) 40 provided on the top side of the tank 20, an obstruction means 50 that blocks the path of the ladder 30, a detection means 60 that detects the state of the handrail 40, and a scaffolding 70 provided on the top of the tank 20. The tank 20 has a substantially elliptical vertical cross section and stores water, etc. The ladder 30 is used to climb up to the tank 20 and is provided on the rear side of the tank 20.

[0022] A pair of handrails 40 are provided on the left and right ends of the tank 20, and can be moved up and down from an upper limit position to a lower limit position. When the handrails 40 are in the upper limit position, they are in an upright state (installed state) with their upper ends positioned at a predetermined level or higher than the top surface of the scaffolding 70, and when they are in the lower limit position, they are in a non-upright state (stored state) with their upper ends positioned near the height of the top surface of the scaffolding 70. By placing the handrails 40 in the upright state, workers who have climbed onto the tank 20 can be prevented from falling. The handrail 40 is moved up and down by manual operation by an operator or the like using a handrail operation switch 80, which can select between an up operation to raise the handrail 40 and a down operation to lower the handrail 40. There are two handrail operation switches 80: an in-cab handrail operation switch 81 and an external handrail operation switch 82 on an external operation panel provided on the side of the vehicle, and either can be used for operation. However, both cannot be used at the same time, and the operator selects whether to use the in-cab handrail operation switch 81 or the external handrail operation switch 82 using an operation selector switch 91. The in-cab handrail operation switch 81 and the operation selector switch 91 are provided on an in-cab operation panel 90 installed inside the cab. The detection means 60 has an upper limit switch that detects when the handrail 40 is at the upper limit position, and a lower limit switch that detects when the handrail 40 is at the lower limit position.

[0023] If the tank car 1 were to travel with the handrail 40 in the upright position, there is a possibility that the handrail 40 would come into contact with pipes, roofs, etc. that are installed at high altitudes. Therefore, the tank car 1 is provided with a parking lever lock mechanism that locks the parking lever (side brake lever) so that the tank car 1 cannot travel unless the handrail 40 is in the upright position. The parking lever lock mechanism utilizes a solenoid, and is configured so that a lock pin pops out when energized and is retracted by the force of a spring when de-energized. When the handrail 40 is in the upright position and the vehicle engine key is ON, an electric current flows through the parking lever lock mechanism. The lock pin that pops out when the current is applied is inserted into the lock pin hole in the parking lever, thereby locking the parking lever.

[0024] In addition, the tank car 1 is provided with a non-standing state operation prevention switch 100 near the top of the handrail 40 to prevent other workers on the ground from accidentally lowering the handrail 40 while a worker is working on the tank 20. The non-standing state operation prevention switch 100 can select between "down operation disabled," which disables the down operation, which is the operation of lowering the handrail 40, among the operations performed by the handrail operation switch 80, and "down operation enabled," which does not disable the down operation.By having the worker going up to the tank 20 select "down operation disabled" on the non-standing state operation prevention switch 100, even if another worker selects the down operation on the handrail operation switch 80, the handrail 40 will not lower, thereby ensuring safety.

[0025] FIG. 2 is a diagram showing the periphery of the location where the obstructing means is provided, with FIG. 2(a) being a left side view and FIG. 2(b) being a rear view. The obstruction means 50 has a main body 51 having a length equal to or greater than the width of the ladder 30. The main body 51 is a rod-shaped member made of metal that can rotate approximately 90 degrees, and is oriented approximately horizontally at the lower limit of rotation and approximately vertically at the upper limit of rotation. The inhibiting means 50 has a base end support portion 52 that supports the base end which is the rotation center of the main body portion 51, an inhibiting fixing portion (horizontal state maintaining portion) 53 that fixes the main body portion 51 in an approximately horizontal orientation, and a rotation inhibiting portion 54 that prevents the main body portion 51 from rotating downward from an approximately vertical orientation. The base end support portion 52 and the rotation prevention portion 54 are provided on one side of the ladder 30 at a position protruding further rearward than the ladder 30 towards the rear of the vehicle. The obstruction fixing portion 53 is provided on the other side of the ladder 30 at a position protruding further rearward than the ladder 30 towards the rear of the vehicle. The rotation prevention portion 54 is located on the base end side of the main body portion 51 and has a pin that can protrude into the rotation path of the main body portion 51. When the main body portion 51 is oriented substantially vertically, if the pin is protruding into the rotation path in the vicinity of the main body portion 51, even if the main body portion 51 tries to rotate downward, it will come into contact with the pin and will not be able to rotate any further, so that the main body portion 51 can be prevented from rotating downward unintentionally. Furthermore, a lock key 55 protrudes from the tip of the main body 51, and the obstruction fixing part 53 has an insertion port into which the lock key 55 is inserted. The obstruction fixing part 53 is, for example, an electromagnetic lock that uses a spring or solenoid. When the handrail 40 is not in an upright position, inserting the lock key 55 into the insertion port with the main body 51 in a substantially horizontal position locks the lock key 55 by the force of the spring, maintaining the obstruction state of the obstruction means 50. At this time, the solenoid is OFF. Then, when a predetermined condition is met, the solenoid turns ON, releasing the lock and allowing the lock key 55 to be removed. Figure 2 shows the main body 51 in an approximately vertical orientation, and at this time, the obstruction means 50 is in a non-obstructive state in which the main body 51 does not cover the ladder 30 and does not block the ascent / descent path when viewed from the front side (rear side of the vehicle), allowing workers to climb up to the tank 20 using the ladder 30. After descending from the tank 20 to the ground, the worker rotates the main body 51 downward to a substantially horizontal orientation and inserts the lock key 55 into the insertion opening of the obstruction fixing part 53. When the handrail 40 is placed in a non-upright position with the lock key 55 inserted, the main body 51 is locked by the obstruction fixing part 53. When the user wishes to climb back onto the tank 20, the lock on the inhibiting fixing part 53 is released and the main body part 51 is rotated upward to a substantially vertical orientation. After the main body part 51 is rotated vertically, the pin of the rotation preventing part 54 is protruded into the rotation range to prevent the main body part 51 from rotating downward unexpectedly.

[0026] FIG. 3 is a diagram showing the periphery of the location where the obstructing means is provided, with FIG. 3(a) being a left side view and FIG. 3(b) being a rear view. 3 shows the main body 51 of the obstructing means 50 in a substantially horizontal orientation. The tip of the substantially horizontally oriented main body 51 is located on the other side of the ladder 30. When the ladder 30 is viewed from the front side (the rear side of the vehicle), the obstructing means 50 in this state is in an obstructing state where the main body 51 covers the ladder 30 and blocks the ascent / descent path, preventing workers from climbing the ladder 30. In this way, the obstructing means 50 can effectively block the path of the ladder 30 with a simple configuration. The distance between the ladder 30 and the main body 51 when the obstructing means 50 is in the obstructing state is set appropriately so that workers cannot climb the ladder 30 by avoiding the main body 51. For example, by setting the horizontal distance between the main body 51, which is oriented approximately horizontally, and the step or side frame of the ladder 30 at the same height to about 20 cm to 30 cm, it is possible to effectively prevent workers from climbing the ladder 30 by passing through the gap between the ladder 30 and the main body 51 or climbing the ladder 30 by straddling the main body 51. Furthermore, the main body 51 is oriented substantially horizontally at heights between the first and second steps of the ladder 30. This makes it easier for workers to recognize that the obstructing means 50 is in an obstructing state before climbing the ladder 30. Furthermore, the main body 51 can be a chain, a door, or the like, but is preferably a hard rod-shaped member such as a metal rod, as in this embodiment. By using a hard rod-shaped member for the main body 51, it is possible to effectively prevent a worker from climbing the ladder 30 by avoiding the main body 51 of the obstructing means 50 in the obstructing state, even with a relatively simple configuration. Furthermore, the main body 51 can rotate up and down around the base end support part 52 as an axis, and the obstruction means 50 can be placed in a non-obstructing state by rotating the main body 51 upward so that it is oriented vertically, and in a obstructing state by rotating the main body 51 downward so that it is oriented horizontally, so that the obstructing state and the non-obstructing state can be easily and quickly switched between.

[0027] The tank car 1 is equipped with a control means, and the control means controls the locking and unlocking of the obstruction fixing part 53. Figure 4 is a diagram showing the control flow of the control means for the obstruction fixing part. The control means first determines whether the engine key of the vehicle is ON or not (step S1). Although it is possible to control the inhibition fixing unit 53 even when the key is in the ACC (accessory position), it is preferable that the vehicle engine is running to prevent the battery from running out. If the control means determines "Yes" in step S1, that is, if the vehicle engine key is ON, it determines whether the power switch on the control panel is ON (step S2). The power switch on the control panel switches the main power supply ON / OFF.

[0028] If the control means determines "No" in step S2, that is, if the power switch of the control panel is OFF, the control means ends the process. In this case, the lock of the inhibition fixing unit 53 is not released. On the other hand, if it is determined in step S2 that the power switch on the control panel is "Yes," that is, if it is determined that the power switch on the in-cab operation panel 90 is ON, it is determined whether or not the power switch on the in-cab operation panel 90 is ON (step S3).

[0029] If the control means determines "No" in step S3, that is, if the power switch of the in-cab operation panel 90 is OFF, the control means ends the process. In this case, the lock of the obstruction fixing unit 53 is not released. On the other hand, if it is determined in step S3 that the answer is "Yes," that is, if it is determined that the power switch on the in-cab operation panel 90 is ON, it is determined whether or not the handrail 40 is at the upper limit position (step S4).

[0030] If the control means determines "No" in step S4, that is, if it determines that the handrail 40 is not at the upper limit position, the control means ends the process. In this case, the lock of the obstruction fixing portion 53 is not released. On the other hand, if the answer to step S4 is "Yes," that is, if it is determined that the handrail 40 is at the upper limit position, the lock on the obstruction fixing part 53 is released (step S5). In this way, the lock of the obstructing fixing part 53 is released only when the handrail 40 is in the upper limit position, so in principle, the worker cannot put the obstructing means 50 into the non-obstructing state when the handrail 40 is not in the upright state. Therefore, the worker is prevented from climbing onto the tank 20 when the handrail 40 is not in the upright state.

[0031] If the control means determines "No" in step S1, that is, that the engine key of the vehicle is OFF, it determines whether or not the special switch is ON (step S6). If the control means determines "No" in step S6, that is, if the special switch is OFF, the process ends. In this case, the lock of the inhibition fixing unit 53 is not released. On the other hand, if it is determined in step S6 that the result is "Yes," that is, if it is determined that the special switch is ON, the process proceeds to step S5, where the lock on the inhibition fixing unit 53 is released. For safety reasons, the lock on the obstruction fixing part 53 will not be released unless the handrail 40 is in the upper limit position, but depending on the work situation, there may be cases where workers are forced to climb onto the tank 20 with the handrail 40 not deployed, and providing an exception switch can be used to deal with such situations. Note that, because the unlocking of the obstruction fixing part 53 by turning on the exception switch is an exception only, it is preferable that the exception switch be installed in a location where it cannot be easily touched by people and that measures be taken to prevent it from being turned on unintentionally, such as by enclosing it in a cover.

[0032] The control means also controls the up and down movement of the handrail 40. Figure 5 is a diagram showing the main flow of control over the up and down movement of the handrail. The control means first determines whether the engine key of the vehicle is ON or not (step S11). Note that, even if the ACC (accessory position) is selected, the handrail 40 can be moved up and down, but it is preferable that the vehicle engine is running to prevent the battery from running out. If the control means determines "No" in step S11, that is, if the engine key of the vehicle is turned off, the process ends. In this case, the worker cannot move the handrail 40 up and down. On the other hand, if the answer is "Yes" in step S11, that is, if it is determined that the engine key of the vehicle is ON, it is determined whether the power switch of the control panel is ON (step S12).

[0033] If the control means determines "No" in step S12, that is, if the power switch on the control panel is OFF, the control means ends the process. In this case, the worker cannot move the handrail 40 up and down. On the other hand, if it is determined in step S12 that the power switch of the control panel is "Yes," that is, if it is determined that the power switch of the in-cab operation panel 90 is ON, it is determined whether or not the power switch of the in-cab operation panel 90 is ON (step S13).

[0034] If the control means determines "No" in step S13, that is, if the power switch of the in-cab operation panel 90 is OFF, the control means ends the process. In this case, the operator cannot move the handrail 40 up and down. On the other hand, if it is determined in step S13 that the answer is "Yes," that is, that the power switch on the in-cab operation panel 90 is ON, it is determined whether or not the handrail 40 is at the upper limit position (step S14).

[0035] If the control means determines "Yes" in step S14, that is, that the handrail 40 is at the upper limit position, it enters a state in which it is ready to accept handrail up / down operation processing based on the handrail upper limit position. In this case, the worker can operate the handrail 40. On the other hand, if the answer to step S14 is "No," that is, if it is determined that the handrail 40 is not at the upper limit position, it is determined whether or not the handrail 40 is at the lower limit position (step S15). The order of steps S14 and S15 may be reversed. That is, it is also possible to determine whether the handrail 40 is at the lower limit position, and then determine whether the handrail 40 is at the upper limit position.

[0036] If the control means determines "Yes" in step S15, that is, that the handrail 40 is at the lowest position, it enters a state in which it is ready to accept handrail up / down operation processing based on the handrail lowest position. In this case, the worker can also operate the handrail 40. If step S15 returns "No," that is, if it is determined that the handrail 40 is not at the lowest position, the system enters a state in which it is ready to accept handrail up / down operation processing based on the intermediate handrail position. In this case, the worker can still operate the handrail 40.

[0037] FIG. 6 is a diagram showing a flow of handrail up / down operation processing based on the handrail upper limit position. As described above, when the control means determines that the handrail 40 is at the upper limit position, it performs the handrail up / down operation process based on the handrail upper limit position. When the handrail 40 is in the upper limit position, i.e., in the upright state, the upper limit lamp, red light, and warning buzzer provided on the in-cab control panel 90 are set to be ON to alert those in the vicinity, so that the upper limit lamp and red light come on and the warning buzzer sounds. Also, because the parking lever is locked by the parking lever lock mechanism described above, the tanker 1 cannot be driven.

[0038] The control means determines whether the cab inside handrail operation switch 81 or the outside handrail operation switch 82 is selected on the operation changeover switch 91 (step S21). If it is determined in step S21 that the in-cab handrail operating switch 81 is selected, it is determined whether or not the up operation is selected on the in-cab handrail operating switch 81 (step S31). On the other hand, if it is determined in step S21 that the external handrail operating switch 82 is selected, it is determined whether or not the up operation is selected on the external handrail operating switch 82 (step S41).

[0039] If the control means determines "Yes" in step S31 or step S41, that is, that the up operation has been selected, it invalidates the up operation and ends the process. On the other hand, if it is determined in step S31 that "No," that is, that the up operation has not been selected, it is determined whether the down operation has been selected with the in-cab handrail operating switch 81 (step S32). If it is determined in step S41 that "No," that is, that the up operation has not been selected, it is determined whether or not the down operation has been selected with the external handrail operation switch 82 (step S42).

[0040] If the control means determines "No" in step S32 or step S42, that is, if it determines that the down operation has not been selected, it ends the process. On the other hand, if it is determined that "Yes" in step S32 or step S42, that is, that the down operation has been selected, it is determined whether the parking brake is ON (step S33, step S43).

[0041] If the control means determines "No" in step S33 or step S43, that is, if the control means determines that the parking brake is not ON, it invalidates the down operation and ends the process. On the other hand, if the answer is "Yes" in step S33 or step S43, i.e., if the parking brake is ON, it is determined whether the lock key 55 attached to the main body 51 of the inhibiting means 50 is inserted into the inhibiting fixing portion 53 (in an inhibiting state) (step S34, step S44).

[0042] If the control means determines "No" in step S34 or step S44, i.e., that the lock key 55 attached to the main body 51 of the obstruction means 50 is not inserted into the obstruction fixing portion 53, it invalidates the downward operation and terminates the processing. On the other hand, if the answer is "Yes" in step S34 or step S44, that is, if it is determined that the lock key 55 attached to the main body 51 of the inhibiting means 50 is inserted into the inhibiting fixing portion 53, it is determined whether or not the down operation enable is selected in the non-standing state operation prevention switch 100 (step S35, step S45).

[0043] If the control means determines "No" in step S35 or step S45, that is, if it determines that the down operation enable has not been selected in the non-standing state operation prevention switch 100, it invalidates the down operation and ends the process. On the other hand, if it is determined in step S35 or step S45 that "Yes", that is, if it is determined that the non-standing state operation prevention switch 100 has selected "down operation enabled", the handrail 40 is moved downward. In this way, by making it so that the handrail 40 cannot be lowered unless the lock key 55 attached to the main body 51 of the obstruction means 50 is inserted into the obstruction fixing portion 53, the handrail 40 can be reliably maintained in an upright position when an operator is on the tank 20, thereby increasing safety. Furthermore, if "downward operation disabled" is selected on the non-standing state operation prevention switch 100, even if a worker on the ground inserts the lock key 55 attached to the main body 51 into the obstruction fixing part 53 and then selects downward operation on the handrail operation switch 80 while there are still other workers on the tank 20, the handrail 40 will not lower, ensuring the safety of the workers on the tank 20.

[0044] FIG. 7 is a diagram showing the flow of the handrail up / down operation process based on the handrail lower limit position. As described above, when the control means determines that the handrail 40 is at the lowest limit position, it performs handrail up / down operation processing based on the handrail lowest limit position. When the handrail 40 is in the lowest position, i.e., when it is not in an upright position, the lower limit lamp is set to be ON and illuminated.

[0045] The control means determines whether the cab inside handrail operation switch 81 or the outside handrail operation switch 82 is selected on the operation changeover switch 91 (step S51). If it is determined in step S51 that the in-cab handrail operating switch 81 is selected, it is determined whether or not the up operation is selected on the in-cab handrail operating switch 81 (step S61). On the other hand, if it is determined in step S51 that the external handrail operating switch 82 is selected, it is determined whether or not the up operation is selected on the external handrail operating switch 82 (step S71).

[0046] If the control means determines "Yes" in step S61 or step S71, that is, if it determines that the up operation has been selected, it determines whether or not the parking brake is ON (step S62, step S72). If the control means determines "Yes" in step S62 or step S72, that is, if the parking brake is ON, the control means moves the handrail 40 upward. On the other hand, if the answer is "No" in step S62 or step S72, that is, if it is determined that the parking brake is not ON, the up operation is invalidated and the process ends.

[0047] Furthermore, if the control means determines "No" in step S61, i.e., that the up operation has not been selected, it determines whether or not the down operation has been selected with the in-cab handrail operation switch 81 (step S63). Similarly, if the control means determines "No" in step S71, i.e., that the up operation has not been selected, it determines whether or not the down operation has been selected with the external handrail operation switch 82 (step S73). If the control means determines "Yes" in step S63 or step S73, that is, that the down operation has been selected, it invalidates the down operation and returns to step S51. On the other hand, if it is determined in step S63 or step S73 that the answer is "No," that is, if it is determined that the down operation has not been selected, the process ends.

[0048] FIG. 8 is a diagram showing the flow of the handrail up / down operation process based on the handrail midway position. As described above, when the control means determines that the handrail 40 is in the midway position, it performs the handrail up / down operation process based on the midway position. When the handrail 40 is between the upper and lower limit positions, the red light and alarm buzzer on the in-cab control panel 90 are set to be ON to alert those in the vicinity, so that the red light comes on and the alarm buzzer sounds. Also, because the parking lever is locked by the parking lever lock mechanism described above, the tanker 1 cannot be driven.

[0049] The control means determines whether the cab inside handrail operation switch 81 or the outside handrail operation switch 82 is selected on the operation changeover switch 91 (step S81). If it is determined in step S81 that the in-cab handrail operating switch 81 is selected, it is determined whether or not the up operation is selected on the in-cab handrail operating switch 81 (step S91). On the other hand, if it is determined in step S81 that the external handrail operating switch 82 is selected, it is determined whether or not the up operation is selected on the external handrail operating switch 82 (step S101).

[0050] If the control means determines "Yes" in step S91 or step S101, that is, that the up operation has been selected, the control means determines whether the parking brake is ON (step S92, step S102). If the control means determines "Yes" in step S92 or step S102, that is, if the parking brake is ON, the control means moves the handrail 40 upward. On the other hand, if the answer is "No" in step S92 or step S102, that is, if it is determined that the parking brake is not ON, the up operation is invalidated and the process ends.

[0051] Furthermore, if the control means determines "No" in step S91, i.e., that the up operation has not been selected, it determines whether or not the down operation has been selected with the in-cab handrail operation switch 81 (step S93). Similarly, if the control means determines "No" in step S101, i.e., that the up operation has not been selected, it determines whether or not the down operation has been selected with the external handrail operation switch 82 (step S103). If the control means determines "No" in step S93 or step S103, that is, if it determines that the down operation has not been selected, it ends the process. On the other hand, if it is determined that "Yes" in step S93 or step S103, that is, that the down operation has been selected, it is determined whether the parking brake is ON (step S94, step S104).

[0052] If the control means determines "No" in step S94 or step S104, that is, if the control means determines that the parking brake is not ON, it invalidates the down operation and ends the process. On the other hand, if the answer is "Yes" in step S94 or step S104, i.e., if the parking brake is ON, it is determined whether the lock key 55 attached to the main body 51 of the inhibiting means 50 is inserted into the inhibiting fixing portion 53 (in an inhibiting state) (step S95, step S105).

[0053] If the control means determines "No" in step S95 or step S105, i.e., that the lock key 55 attached to the main body 51 of the obstruction means 50 is not inserted into the obstruction fixing portion 53, it invalidates the downward operation and terminates the processing. On the other hand, if the answer is "Yes" in step S95 or step S105, that is, if it is determined that the lock key 55 attached to the main body 51 of the obstruction means 50 is inserted into the obstruction fixing portion 53, it is determined whether or not the down operation enable is selected in the non-standing state operation prevention switch 100 (step S96, step S106).

[0054] If the control means determines "No" in step S96 or step S106, that is, if it determines that the down operation enable has not been selected in the non-standing state operation prevention switch 100, it invalidates the down operation and ends the process. On the other hand, if it is determined in step S96 or step S106 that "Yes", that is, if it is determined that the down operation enable is selected in the non-standing state operation prevention switch 100, the handrail 40 is moved down. In this way, by making it so that the handrail 40 cannot be lowered unless the lock key 55 attached to the main body 51 of the obstruction means 50 is inserted into the obstruction fixing portion 53, safety for workers when they are on the tank 20 can be increased. Furthermore, if "downward operation disabled" is selected on the non-standing state operation prevention switch 100, even if a worker on the ground inserts the lock key 55 attached to the main body 51 into the obstruction fixing part 53 and then selects downward operation on the handrail operation switch 80 while there are still other workers on the tank 20, the handrail 40 will not lower, making it easier to ensure the safety of workers on the tank 20. [Explanation of symbols]

[0055] 1 tank car 20 Tank 30 ladder 40 Handrail 50 Obstruction measures 51 Main body 52 Proximal support part 53 Inhibitory fixation part 60 Detection Methods 80 Handrail operation switch 100 Non-standing state operation prevention switch

Claims

1. A tank mounted on the vehicle; a ladder for climbing onto the tank; A handrail provided on the upper surface side of the tank and capable of being changed between an upright state and a non-upright state; A handrail operation switch used to operate the handrail to the upright state or the non-upright state; an obstructing means that can be changed between an obstructing state that obstructs the ladder's path and a non-obstructing state that does not obstruct the path; A detection means for detecting the standing state and the non-standing state of the handrail; a control unit that determines a detection result by the detection unit, the inhibiting means has an inhibiting fixing part that fixes the inhibiting state, A tank car characterized in that the control means maintains the fixation by the obstruction fixation part when it determines from the detection result of the detection means that the handrail is in a non-upright state.

2. 2. A tank car as described in claim 1, characterized in that when the obstructing means is not in the obstructing state, operations using the handrail operation switch to place the handrail in the non-upright state are invalid.

3. 3. The tank car according to claim 2, further comprising a non-standing state operation prevention switch that disables operations using the handrail operation switch to place the handrail in a non-standing state.

4. A tank car described in any one of claims 1 to 3, characterized in that the obstructing means has a main body portion having a length greater than or equal to the width of the ladder, and a base end support portion provided on one side of the ladder and supporting the base end of the main body portion, and the obstructing state is achieved by the main body portion being oriented horizontally so that its tip is positioned on the other side of the ladder, blocking the path of the ladder.

5. 5. The tank car according to claim 4, wherein the main body is oriented horizontally at a height between the first and second steps of the ladder.

6. 6. The tank car according to claim 4, wherein the main body is a hard rod-shaped member.

7. The tank car described in claim 6, characterized in that the main body portion is rotatable up and down around the base end support portion as an axis, and the obstructing means enters the non-obstructing state by rotating the main body portion upward to a vertical orientation, and enters the obstructing state by rotating the main body portion downward to a horizontal orientation.

Images