Work platform with hand-pinch prevention mechanism for working at heights

Abstract

To provide a mechanism to protect a hand other than the one holding the control lever from obstacles, on a workbench when a worker performs the lifting operation using the operating lever on the workbench for high places.SOLUTION: A workbench 1 comprises a vertical frame 3 arranged around a work floor 2 for a worker, a handrail 4 constructed between the upper end parts of adjacent vertical frames 3, 3, and a control lever 6 to control a lifting operation inside the space divided by the vertical frame 3 and the handrail 4. A handle 7 with a detector is installed at the position below the handrail 4 inside the workbench, and the detector has the function to switch between enabling and disabling lifting operation of the work bench 1 using the operation lever 6 and enables the lifting operation using the operation lever 6 when the worker grasps the lever.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a workbench with a mechanism for preventing hand pinching during high-altitude work, which is provided with a mechanism for preventing a situation where, when an operator performs a raising operation using an operation lever on a workbench at a high place, the hand on the opposite side of the hand operating the operation lever is sandwiched between a structure or installed equipment.

Background Art

[0002] A workbench (basket) that is vertically supported on a traveling vehicle and on which an operator performs work at a high place is raised and lowered mainly by operating an operation lever of an operation panel installed inside the workbench (see Patent Document 1). For the purpose of ensuring the safety and reliability of the operation by the operation lever, there is also a control method in which the operation of the operation lever becomes effective only when a foot switch installed on the work floor of the workbench is depressed (see Patent Document 2).

[0003] Since the operation lever is operated with one hand of the operator, in order to ensure the stability of the operator himself / herself when the workbench is raised and lowered, the operator tries to grasp the handrail with the other hand, so there is a risk that an obstacle such as a constructed structure (frame) or installed equipment will come into contact with or collide with the hand holding the handrail.

[0004] An operator who is operating the operation lever while holding the handrail is mainly likely to face the above risk when the workbench is rising. Therefore, it is necessary to devise a way to prevent an obstacle that relatively descends during the rising of the workbench from directly contacting the handrail.

[0005] As such a method, there are a method of arranging a movable handrail that can move along the handrail inside the original handrail that is a part of the workbench and using the original handrail as a guard member to avoid an obstacle hitting the hand (see Patent Document 3), and a method of attaching a guard member that moves up and down outside the handrail to the handrail (see Patent Document 4). However, there is no guarantee that a hand other than the hand holding the operation lever can always hold a guard member other than the handrail in an emergency.

[0006] On the other hand, there is a method to enable (make effective) operation of the operating lever by having the operator hold the operating lever and continue to press it with any finger of the same hand only when the operator is gripping the lever and attempting to operate it (see Patent Document 5). [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] Japanese Patent Publication No. 2003-73094 (Claim 1, paragraphs 0012-0017, Figure 2) [Patent Document 2] Japanese Patent Publication No. 62-205995 (Claim 1, Figure 3) [Patent Document 3] Japanese Patent Publication No. 2021-138504 (Claim 1, paragraphs 0018-0040, Figures 1-8) [Patent Document 4] Japanese Patent Publication No. 2021-88433 (Claim 1, paragraphs 0018-0030, Figure 1, Figure 2) [Patent Document 5] Japanese Patent Publication No. 2021-31293 (Claim 1, paragraphs 0010-0016, 0025, 0033, 0050-0059, Figure 3) [Overview of the project] [Problems that the invention aims to solve]

[0008] However, Patent Document 5 merely equips the operating lever with an additional safety switch for the purpose of preventing accidental operation by the operating lever alone, and does not provide guidance to move any hand other than the hand operating the operating lever away from the handrail, so there is no guarantee that the hand other than the hand gripping the operating lever can be reliably protected from obstacles.

[0009] Based on the above background, the present invention proposes a work platform with a hand-pinch prevention mechanism for working at heights that makes it possible to protect hands other than the hand gripping the operating lever from obstacles. [Means for solving the problem]

[0010] The work platform with a hand-pinching prevention mechanism for working at height according to claim 1 is supported on a traveling vehicle so as to be able to move up and down vertically, and comprises vertical frames arranged at circumferential intervals around a work platform on which a worker stands, a handrail installed between the upper ends of adjacent vertical frames, and at least an operating lever for controlling the raising operation located inside the space partitioned by the vertical frames and the handrail, A handle is mounted on the inside of the workbench, below the handrail, which has a detector that switches between a state where the workbench can be raised and a state where it cannot be raised when the operating lever is held by the worker, and enables the raising operation by the operating lever. 、 The detector enables the raising operation by the operating lever when the handle is being grasped or pressed by the operator, and disables the raising operation by the operating lever when the handle is not being grasped or pressed by the operator. The aforementioned handle consists of two handle materials placed parallel to each other at an appropriate distance, and these two handle materials are arranged so that they approach or touch each other when grasped by the worker with one hand. The constituent element is that this is the case.

[0011] Vehicles that support work platforms (aerial work platforms) include wheeled types, where tires roll on the road surface, and crawler types, where tracks roll. In terms of the vehicle's form, there are truck-mounted and self-propelled types. Lifting devices that support the work platform so that it can be raised and lowered include boom types (hydraulic cylinder type) or digging (telescopic) types that extend and lower in the axial direction, and vertical lifting types (scissors type) that extend and lower vertically like a pantograph. "Freely able to be raised and lowered" mainly refers to being able to move up and down in the vertical direction, but it also includes vertical movement accompanied by horizontal movement.

[0012] As shown in Figure 1-(a), the work platform 1 basically consists of a work floor 2, multiple vertical frames 3 fixed around the perimeter of the work floor 2, and handrails 4 supported at the upper ends of the vertical frames 3. The vertical frames 3 and handrails 4 demarcate the inside and outside of the work platform 1. Horizontal frames or doors may be installed between adjacent vertical frames 3, 3. An operation panel 5 equipped with an operating lever 6 is mounted on the inside of the work platform 1. The handrails 4 can be grasped by the worker when the work platform 1 is not being raised by the operating lever 6.

[0013] Since the operating lever 6 is held by the worker at least when the work platform 1 is raised, the entire operating lever 6 is positioned below the handrail 4, as shown in Figure 2, so that no part of the hand gripping the operating lever 6 protrudes above the upper surface of the handrail 4, preventing any obstruction from coming into contact with or colliding with the hand during the raising process. The handrails 4 are arranged continuously or intermittently around the circumferential direction of the work platform 1 (work floor 2).

[0014] "At least controlling the upward operation" means that the operating lever 6 may control not only the upward movement of the workbench 1, but also its downward movement, or both. "Controlling" refers to the control by the operating lever 6 to the controller when the operating lever 6 is pushed or tilted in the upward operation direction, causing the lifting device 11 (or its drive unit) that supports the workbench 1 to raise the workbench 1 based on a command from the controller built into the control panel 5, etc. When the operating lever 6 is operated, a signal to perform an upward operation is transmitted from the operating lever 6 to the controller, and a command from the controller based on the signal is transmitted to the lifting device 11. Note that the control of the workbench 1's upward movement by the operating lever 6 is sometimes simply referred to as the upward operation.

[0015] A handle 7 equipped with a sensor or other detector that enables the workbench 1 to be raised using an operating lever 6 is mounted on the inside of the workbench 1, below the handrail 4. Since the handle 7 is also held by the worker at least when the workbench 1 is raised, it is positioned below the handrail 4 so that no obstacles come into contact with the hand holding the handle 7 during the raising process, and no part of the hand holding the handle 7 protrudes above the handrail 4.

[0016] The handle 7 is grasped by the hand opposite to the hand (one hand) that is grasping the operating lever 6 while the worker is operating the operating lever 6. The left or right hand that grasps the operating lever 6 and the handle 7 does not matter. When the worker grasps the handle 7, the worker will be grasping the operating lever 6 with one hand and the handle 7 with the other hand, so both of the worker's hands will be simultaneously gripping two points on the workbench 1 to enable the upward operation using the operating lever 6.

[0017] "Making the upward operation by the operation lever 6 possible" means that when the operation lever 6 is operated to the upward operation side, and at the same time the handle 7 is gripped, the detector detects that the handle 7 is gripped, and the controller gives an "upward" command to the lifting device 11 (turns on the switch described later). The detector detects changes such as pressure when the handle 7 is gripped as described later.

[0018] Therefore, in order to make the upward operation by the operation lever 6 with one hand possible, it is essential to grip the handle 7 with the detector with the other hand. So, when the operator raises the workbench 1, it is necessary to grip the operation lever 6 with one hand and at the same time grip the handle 7 with the detector with the other hand. As a result, when the workbench 1 is rising, the operator's hands will not grip the handrail 4, and the handle 7 serves as a guiding measure to move the hand other than the hand operating the operation lever 6 away from the handrail 4.

[0019] In this way, when both hands of the operator are placed in the state of simultaneously gripping the operation lever 6 and the handle 7 which are part of the workbench 1, the operator will inevitably take a posture (body position) of gripping the handle 7 instead of the handrail 4 while gripping the operation lever 6. Since the operation lever 6 and the handle 7 are located below the handrail, even when the workbench 1 rises and the obstacle relatively descends, it is avoided that the obstacle contacts or collides with the operator's hand. The hand other than the hand gripping the operation lever 6 is surely protected from the obstacle, ensuring the safety of the operator.

[0020] The detector of the handle 7 has a function of switching between the possible state and the impossible state of the upward operation of the workbench 1 by the operation lever 6, and makes the upward operation by the operation lever 6 possible only when it is gripped or pushed by the operator, etc. That is, in the non-functional state, the detector restricts the upward operation by only the operation lever 6 and keeps the operation lever 6 in a restrained (locked) state.

[0021] The function of the detector that switches between the enabled and disabled states of the lifting operation of the workbench 1 by the operation lever 6 is, for example, a piezoelectric element or other pressure sensor or contact sensor built into or attached to the handle 7 itself or any part of the handle 7. When a change in pressure or the like when the handle 7 is gripped is detected, it detects that the handle 7 has been gripped, and the signal at this time enables the lifting operation (control) by the operation lever 6. In addition to this, there is also a form (capacitance type touch panel) in which the detector detects a change in capacitance due to a weak current generated when a finger directly touches the surface of the detector.

[0022] The signal detected by the detector turns on the switch 7a of the handle 7 (detector) that enables the lifting operation by the operation lever 6 as shown in Fig. 4-(b), and keeps the switch 7a off when the detector does not detect a change in pressure or the like. When the switch 7a of the handle 7 (detector) is turned on, a command for the lifting operation is transmitted from the controller to the drive unit of the lifting device 11.

[0023] The switch 7a of the handle 7 is connected in series with the command for the lifting operation from the controller by the operation lever 6 to the lifting device 11. When the switch 7a of the handle 7 is kept off, the operation of the operation lever 6 has no effect, or even if the operation lever 6 is operated, no command is transmitted from the controller to the lifting device 11, and the workbench 1 does not rise.

[0024] The handle 7 only needs to have the function of switching between the enabled and disabled states of the lifting operation of the workbench 1 by the operation lever 6. Inspect A secondary switch 8 that exhibits the same function as the detector can be provided together with the handle 7 (Claim 2). The "secondary switch that exhibits the same function as the detector" means that the secondary switch 8, such as the push button switch shown in Fig. 3-(b), has the function of switching between the enabled and disabled states of the lifting operation of the workbench 1 by the operation lever 6 and enabling the lifting operation by the operation lever 6 when the handle 7 is gripped by the operator.

[0025] "Instead of the detector" (Reference example) This means that the secondary switch 8 takes over the role of the detector, and regardless of whether the detector has detected the aforementioned pressure or other changes, pressing or otherwise operating the secondary switch 8 enables the upward operation using the operating lever 6.

[0026] "Together with the detector" means that the detector and the secondary switch 8 are used in conjunction, and that the detector and the secondary switch 8 restrict (restrain) the upward operation by the operating lever 6 in two stages. In other words, after the detector detects the above-mentioned pressure or capacitance changes, the secondary switch 8 is operated, and as shown in Figure 5-(b), the switch 7a on the handle 7 (detector) and the secondary switch 8 turn ON, and only then does the upward operation by the operating lever 6 become possible. The form of the secondary switch 8 is not limited; a push button switch or a changeover switch can be used.

[0027] In the case of having a secondary switch 8, the work platform 1 is supported on the traveling vehicle 10 so as to be able to move up and down vertically, and comprises vertical frames 3 arranged at circumferential intervals around the work platform 2 on which the worker stands, a handrail 4 installed between the upper ends of adjacent vertical frames 3, 3, and at least an operating lever 6 for controlling the raising operation located inside the space partitioned by the vertical frames 3 and the handrail 4 (Claim 2). A handle equipped with a detector is mounted inside the work platform 1, below the handrail 4, which switches between a state where the work platform 1 can be raised and a state where it cannot be raised when the operating lever 6 is grasped by the worker, and enables the raising operation by the operating lever 6 (Claim 2).

[0028] Furthermore, while the handle 7 is being held, the system switches between a state where the workbench 1 can be raised by the operating lever 6 and a state where it cannot be raised, and together with a detector that enables the raising operation by the operating lever 6 when the handle 7 is being held by the worker. Miscellaneous A secondary switch 8 is provided on the handle 7 to enable the upward operation using the operating lever 6 (Claim 2). The "function of enabling the upward operation using the operating lever 6" is performed by the detector, the secondary switch 8, or both the detector and the secondary switch 8.

[0029] The "handle having a function to enable the raising operation" refers to the above-mentioned detector and secondary switch 8, which have the function of "switching between a state where the workbench 1 can be raised by the operating lever 6 and a state where it cannot be raised, and enabling the raising operation by the operating lever 6 only when the handle 7 is being held by the worker." of This refers to the fact that handle 7 is equipped with it.

[0030] Handle 7 is 2 Because it has a secondary switch 8, the switch on the operating lever 6 remains OFF unless the secondary switch 8 is operated, and operation by the operating lever 6 is ineffective. The detector on the handle 7, or the detector and the secondary switch 8, are connected in series with the command for upward operation from the controller to the lifting device 11 by the operating lever 6, as shown in Figure 5-(b).

[0031] In claim 2, a secondary switch 8 is provided on the handle 7 along with the detector, and when the secondary switch 8 is operated after the detector detects a change in pressure or the like, the upward operation by the operating lever 6 can be restricted (locked) in two stages as described above, thereby increasing the reliability and safety of the upward operation by the operating lever 6.

[0032] In addition to the above, the reliability and safety of the lifting operation by the operating lever 6 can also be improved by installing a foot switch 9 on the work platform 2 in claim 1 or claim 2, which enables the lifting operation by the operating lever 6 when it is being stepped on by an operator (claim 3).

[0033] In addition to the detector attached to the handle 7, or the detector and secondary switch 8, the work platform 2 is equipped with a foot switch 9 that enables the raising operation by the operating lever 6 only when it is being stepped on by an operator. As a result, the detector and foot switch 9 restrict (restrain) the raising operation by the operating lever 6. Therefore, as shown in Figure 7-(b), the raising operation by the operating lever 6 can be restricted (locked) in three stages, thereby increasing the reliability and safety of the raising operation by the operating lever 6.

[0034] In this case, as shown in Figure 6-(b), the detector detects changes in pressure, etc. a Alternatively, as shown in Figure 7-(b), when the detector detects a change in pressure or other parameters, and the secondary switch 8 is operated, and the foot switch 9 is pressed, both the switch on the handle 7 (either the detector or the secondary switch 8) and the foot switch 9 turn ON, and only then does the lifting operation using the operating lever 6 become possible. In this way, when the detector on the handle 7 and the secondary switch 8 are used together, the lifting operation using the operating lever 6 is limited (locked) to three stages. [Effects of the Invention]

[0035] A handle is installed on the inside of the workbench, below the handrail, that can be gripped by the worker. This handle has a detector that switches between enabling and disabling the raising operation of the workbench via an operating lever, and enables the raising operation when the worker is gripping it. This allows the worker to simultaneously grip both the operating lever and the handle, which are part of the workbench, with both hands. Because the operating lever and the handle are located below the handrail, even when the workbench is raised, obstacles will not come into contact with or collide with the worker's hands. This ensures that the hands other than the one gripping the operating lever are protected from obstacles, thus ensuring worker safety. [Brief explanation of the drawing]

[0036] [Figure 1] (a) is an elevation view of a vehicle showing the lifting device supporting the workbench extending from a retracted state and the workbench rising, and (b) is a side view of (a). [Figure 2] This is a perspective view showing an example of the arrangement of an operating device and control panel with operating levers, and handles, mounted inside a workbench, for controlling the overall operation of a moving vehicle. [Figure 3] (a) is a perspective view showing an example of a handle with a detector, and (b) is a perspective view showing an example of a handle with a secondary switch (reference example). [Figure 4](a) is a schematic diagram showing the signal flow to the lifting device to be operated upward by the operating lever, the upward operation by the lifting device, and the relationship with the switch on the handle. (b) is a block diagram showing how the signal from the operating lever in (a) is switched by the switch on the handle. [Figure 5] (a) is a schematic diagram showing the signal flow to the lifting device to be operated upward by the operating lever, the upward operation by the lifting device, and the relationship between the handle switch and the secondary switch. (b) is a block diagram showing how the signal from the operating lever in (a) is switched by the handle switch and the secondary switch. [Figure 6] (a) is a schematic diagram showing the signal flow to the lifting device to be operated upward by the operating lever, the upward operation by the lifting device, and the relationship between the foot switch and the handle switch. (b) is a block diagram showing an example of how the signal from the operating lever in (a) is switched by the foot switch and the handle switch. [Figure 7] (a) is a schematic diagram showing the signal flow to the lifting device to be operated upward by the operating lever, the upward operation by the lifting device, and the relationship between the foot switch and the switch on the handle which a secondary switch is also installed. (b) is a block diagram showing an example of how the signal from the operating lever in (a) is switched by the foot switch and the switch on the handle. [Modes for carrying out the invention]

[0037] Figures 1-(a) and 1-(b) show an example configuration of a work platform 1 for working at height, which is supported on a traveling vehicle 10 so as to be able to move up and down vertically and is equipped with at least one operating lever 6 on the inside for controlling the raising operation.

[0038] The work platform 1 comprises a work floor 2 on which the worker stands, vertical frames 3 arranged circumferentially at intervals around the work platform 2, and at least handrails 4 that can be grasped by the worker and are installed between the upper ends of adjacent vertical frames 3, 3. As shown in Figure 2, an operating panel 5 including an operating lever 6 is mounted on the inside of the work platform 2. The work platform 1 is placed and fixed on a retractable lifting device 11 supported on a vehicle 10, for example, as shown in Figure 1-(a). The work platform 1 is supported on the vehicle 10 so as to be able to move up and down as the lifting device 11 extends and retracts.

[0039] As shown in Figure 2, an operating device 12 and an operating panel 5 are mounted inside the work platform 1 to control the forward, reverse, and other overall operations of the vehicle 10. The entire operating lever 6 is positioned below the handrail 4 so that when the work platform 1 is raised, the operator's hand will not come into contact with any obstacles while the lever is being held.

[0040] On the inside of the workbench 1, for example, on the front or side of the operating device 12, a handle 7 equipped with a sensor or other detector is attached to switch between a state where the workbench 1 can be raised by the operating lever 6 and a state where it cannot be raised, and to enable the raising operation by the operating lever 6 when it is being held by a worker. The entire handle 7 is also positioned below the handrail 4 so that when it is being held by a worker, no obstacles come into contact with the hand while the workbench 1 is being raised.

[0041] The detector is integrated into or attached to the surface of any part (section) of the handle 7 that is gripped by the operator. The detector may be a pressure sensor or similar sensor that can detect a change in some physical quantity when the handle 7 is grasped with one hand, thereby detecting that the handle 7 is being gripped.

[0042] Figure 3-(a) shows an example of a handle 7 with a detector. This handle 7 is constructed by placing two U-shaped handle materials 71, 71 in parallel at an appropriate distance from each other, and fixing both handle materials 71, 71 to a plate 72 that becomes part of the operating device 12, or a case 73 having the plate 72. The handle materials 71, 71 may be combined in such a way that when grasped by an operator with one hand, at least one of them moves closer to or touches the other, for example, by elastic deformation.

[0043] In this case, when both handles 71, 71 are gripped, the above-mentioned sensor for detecting changes in pressure, etc., is embedded or attached to the surface of at least one of the handles 71. The detector can also use a sensor that detects contact when at least one of the parallel handles 71, 71 elastically deforms and the handles 71, 71 (detectors) come into contact with each other, or a sensor that conducts electricity upon contact, and it is possible to turn on the switch 7a of the handle 7 when detection occurs, and the detector may also serve as the switch 7a.

[0044] In Figure 3-(a), two handle materials 71, 71 are arranged in parallel and joined to the plate 72 to form one handle 7, but (b) (Reference example) In some cases, a single handle material 71 can serve as the handle 7. In such cases, a pressure-detecting sensor is embedded in or attached to the surface of the single handle material 71.

[0045] In the example shown in Figure 3-(a), two handles 71, 71 are gripped, and when the detector detects a change in pressure, etc., the switch 7a on the handle 7 shown in (b) is turned ON, causing the operating lever 6 to be moved to the upward position. This activates the command from the operating lever 6 to the lifting device 11, and the workbench 1 is raised.

[0046] Figure 3-(b)) (Reference example)This example shows a case in which a single handle material 71 is either part of the operating device 12 or joined to a plate 72 of a separate case 73, and a secondary switch 8 such as a push-button switch is installed on a side of the case 73 other than the plate 72, and the secondary switch 8 is given the function of enabling the workbench 1 to be raised by the operating lever 6 together with the detector, or in place of the detector.

[0047] When the secondary switch 8 replaces the detector and enables the upward operation by the operating lever 6: (Reference example) When the secondary switch 8 is pressed or otherwise operated, it functions as the switch 7a of the handle 7 (detector), similar to the example shown in Figure 4-(b). In this case, the switch 7a shown in Figure 4-(b) is replaced by the secondary switch 8.

[0048] When the secondary switch 8, along with the detector, enables the upward operation by the operating lever 6, the switch 7a on the handle 7 and the secondary switch 8 enable the upward operation by the operating lever 6 in two steps, as shown in Figure 5-(b). In Figure 5-(b), the order of switches 7a and secondary switch 8 does not matter. In this case, the upward operation by the operating lever 6 is enabled only when the switch 7a on the handle 7 is turned ON and then the secondary switch 8 is turned ON. Therefore, the upward operation by the operating lever 6 will not be possible unless both are turned ON.

[0049] Example in Figure 3(b) (Reference example) When the handle 7 (handle material 71) is gripped and the detector detects a change in pressure, etc., the secondary switch 8 is operated, causing both the switch 7a on the handle 7 and the secondary switch 8 shown in Figure 5-(b) to turn ON. As a result, the operating lever 6 is moved to the upward position, the command from the operating lever 6 to the lifting device 11 becomes effective, and the workbench 1 rises.

[0050] Figure 6-(a) shows the relationship between the foot switch 9 and the switch 7a on the handle 7, and the operating lever 6 and the lifting device 11, when a foot switch 9 is installed on the work platform 2 of the work platform 1, enabling the work platform 1 to be raised by the operating lever 6 only when it is being stepped on by a worker. Basically, the order of the foot switch 9 and switch 7a is as shown in Figure 6-(b). However, the operating lever 6 and the foot switch 9 do not necessarily have to be connected in series as shown in the diagram; they can also be connected in parallel, and the program may only enable the raising operation by the operating lever 6 when signals from both are detected. In addition, the foot switch 9 may be connected to a motor controller equipped with a fail-safe function, controlling the motor rotation only when a signal is input, and enabling the raising operation by the raising signal.

[0051] In the example shown in Figure 6-(b), the foot switch 9 must be turned ON, and then the switch 7a on the handle 7 must be turned ON for the operating lever 6 to be able to raise the chair. Therefore, unless both are turned ON, the operating lever 6 cannot be used to raise the chair.

[0052] In this example, when the foot switch 9 is pressed and the handle 7 (handle material 71) is grasped, the detector detects a change in pressure, etc., causing both the foot switch 9 and the switch 7a on the handle 7 shown in Figure 6-(b) to turn ON. As a result, the operating lever 6 is moved to the upward position, the command from the operating lever 6 to the lifting device 11 becomes effective, and the workbench 1 rises.

[0053] Figure 7-(a) shows the case where the handle 7 shown in Figure 6-(a) is replaced with the handle 7 shown in Figure 3-(b). (Reference example)This shows the relationship between the foot switch 9 and handle 7, and the operating lever 6 and lifting device 11. In this example, when the foot switch 9 is pressed and the handle 7 is grasped, and the secondary switch 8 is operated, the foot switch 9 and the switch 7a on the handle 7 and the secondary switch 8 shown in Figure 7-(b) are turned ON, and the workbench 1 is raised as the operating lever 6 is moved to the upward position. In this example as well, the operating lever 6 and the foot switch 9 and the switch 7a on the handle 7 and the secondary switch 8 are not necessarily connected in series, but may also be connected in parallel. [Explanation of Symbols]

[0054] 1... Work platform for working at heights, 2...work platform, 3... vertical frame, 4... handrail, 5... Control panel, 6... Operating lever, 7...Handle, 7a...Switch, 71...Handle material, 72...Plate, 73...Case, 8... Secondary switch, 9... Foot switch, 10...Traveling vehicle, 11...Lifting device, 12...Operating device.

Claims

1. A work platform for working at height is provided, which is supported on a moving vehicle so as to be able to move up and down vertically, and is arranged at circumferential intervals around a work platform on which a worker stands, a handrail is installed between the upper ends of adjacent vertical frames, and at least an operating lever for controlling the raising operation is provided inside the space partitioned by the vertical frames and the handrail, A handle is mounted on the inside of the workbench, below the handrail, which has a detector that switches between a state where the workbench can be raised and a state where it cannot be raised when the operating lever is held by the worker, and enables the raising operation by the operating lever. The detector enables the raising operation by the operating lever when the handle is being grasped or pressed by the operator, and disables the raising operation by the operating lever when the handle is not being grasped or pressed by the operator. The aforementioned handle consists of two handle materials placed parallel to each other at an appropriate distance, and these two handle materials are arranged so that they approach each other or come into contact when grasped by the worker with one hand, characterized in that it is a work platform with a hand-pinching prevention mechanism for working at heights.

2. A work platform for working at height is provided, which is supported on a moving vehicle so as to be able to move up and down vertically, and is arranged at circumferential intervals around a work platform on which a worker stands, a handrail is installed between the upper ends of adjacent vertical frames, and at least an operating lever for controlling the raising operation is provided inside the space partitioned by the vertical frames and the handrail, A handle is mounted on the inside of the workbench, below the handrail, which has the function of switching between a state where the workbench can be raised and a state where it cannot be raised when the operating lever is grasped by the worker, and enabling the raising operation by the operating lever. While the handle is being held, the operation lever can switch between a state where the workbench can be raised and a state where it cannot be raised. A detector that enables the operation lever to raise the workbench when the handle is being held by the worker is attached to the handle, along with a secondary switch that enables the operation lever to raise the workbench. The detector enables the raising operation by the operating lever when the handle is being grasped or pressed by the operator, and disables the raising operation by the operating lever when the handle is not being grasped or pressed by the operator. The aforementioned handle consists of two handle materials placed parallel to each other at an appropriate distance, and these two handle materials are arranged so that they approach each other or come into contact when grasped by the worker with one hand, characterized in that it is a work platform with a hand-pinching prevention mechanism for working at heights.

3. A work platform with a hand-pinch prevention mechanism for working at height, as described in claim 1 or 2, is characterized in that a foot switch is mounted on the work platform, which enables the raising operation by the operating lever when the worker is stepping on it.

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