High-altitude work equipment

Abstract

The present invention provides a work device for working at heights that is configured to support the top plate at selectable low and high positions. [Solution] The left and right legs (1A) and (1B) that support the left and right top plates (2A) and (2B) of the top plate body (2) are each composed of a series of ladder legs (10) made by stacking multiple ladder legs (9). The series of legs are configured as telescopic legs in which one of the overlapping ladder legs is connected to the other so that it can slide vertically and engage and disengage at a predetermined sliding position, thereby supporting the top plate body from a low position to a high position. Furthermore, the left and right... This is a work platform for working at heights in which the top plate (2) is in an unfolded position (P1) when the legs (1A) and (1B) are in an open position (L1), and the top plate (2) is in a folded position (P2) when the legs are in a closed position (L2). When the legs are in an open position (L1), a brace device (29) is provided to connect the left and right lower ladder legs (9a) (9a) to each other, and a link device (34) is provided to connect the top plate to the upper ladder legs (9c) to each other.

Description

Technical Field

[0006] , ,

[0007] ,

[0001] The present invention relates to an aerial work device in which a top plate is supported by left and right legs, and more particularly to an aerial work device configured to support the top plate at a selected position between a low position and a high position.

Background Art

[0002] Conventionally, a work device in which a top plate providing a work floor for aerial work is supported by left and right legs is known.

[0003] For aerial work, the work position may be high or low depending on the site. Therefore, it is preferable that the aerial work device can support the top plate at a selected position between a low position and a high position. In that case, it is good to configure the legs as telescopic legs that can be extended and retracted in the vertical direction.

[0004] And, considering the safety and workability of aerial work, it is desirable that the aerial work device provides a wide work floor and is configured such that the legs supporting the top plate are installed stably on the floor.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] In order to meet the above needs, it is inevitable to increase the size of the aerial work device. However, since a large work device has a large weight, when the legs are configured with simple telescopic legs, there is a risk of deformation and deterioration due to the load of the top plate due to insufficient strength.

[0007] Furthermore, the legs supporting the large tabletop are widely spaced apart, making the legs prone to shaking and unstable. Moreover, because the legs supporting the tabletop are also far apart, the central part of the tabletop is not adequately supported.

[0008] Furthermore, as the weight increases, it becomes difficult to lift the top plate from a low position to a high position, and when lowering it from a high position to a low position, there is a risk of the heavy object slipping from the worker's hands and falling.

[0009] Furthermore, it is desirable that larger aerial work equipment be designed to be able to be compactly folded when not in use, but there remains an unresolved problem regarding how to design the folding structure.

[0010] The object of this invention is to provide a high-altitude work device that solves some or all of the above problems. [Means for solving the problem]

[0011] Therefore, the first means configured by the present invention is a high-altitude work device in which a top plate is supported by a pair of legs arranged spaced apart in the left-right X direction with respect to the left-right direction X and the front-back direction Y which are orthogonal on a plane, the top plate is connected so that it can change its posture between an unfolded position in which a pair of top plates divided into left and right are arranged on the same plane and a folded position in which they are bent in a mountain-fold direction and arranged facing each other, the left and right legs are arranged to move so that they can change their posture between an open leg position in which they are spaced apart from each other and a closed leg position in which they are close together, the top plate is in an unfolded position when both legs are in an open leg position and the top plate is in a folded position when they are in a closed leg position, and an internal space is formed between the legs in the open leg position on the underside of the top plate in which a worker can enter and exit, the left and right legs are each connected to a plurality of ladder legs arranged on the inside and outside facing the internal space The structure is configured with a series of interconnected legs, with the innermost ladder leg serving as the lower end ladder leg to allow movement on the floor surface, and the outermost ladder leg serving as the upper end ladder leg to support the top plate. The interconnected legs are configured to be telescopic, with the outer ladder leg slidably connected vertically to the inner ladder leg, so that they contract when the outer ladder leg moves downward and extend when it moves upward. The structure is configured to support the top plate at a high position, raised from a low position, by fixing the inner and outer ladder legs detachably in at least the extended state. Bracing devices are provided on both sides of the internal space in the front-rear direction Y, connecting the lower end ladder legs of the left and right leg bodies to each other. The bracing devices are configured to unfold when the left and right leg bodies are in an open position to support the lower end ladder legs of both leg bodies to each other, and to fold when the leg bodies are in a closed position by bending.

[0012] In the illustrated embodiment, each of the multiple ladder legs constituting the linked legs is composed of a pair of parallel column base members spaced apart in the front-rear direction Y and extending vertically, and a rung installed on the pair of column base members. The bracing device is composed of bracing members that connect the column base members facing each other between the lower end ladder legs of the left and right legs.

[0013] Preferably, the bracing devices arranged on both sides of the internal space in the front-rear direction Y each include a first bracing member and a second bracing member that are flexible from an extended state via a pivot fitting. In this case, the first bracing member and the second bracing member are arranged to cross between one column base member and the other column base member facing each other in the left-right direction X, and when the left and right legs are in an open position, the first bracing member in the extended state is inclined upward from the column base member of one leg member to the column base member of the other leg member, and the second bracing member in the extended state is inclined downward from the column base member of one leg member to the column base member of the other leg member, in which case they support each other. When the left and right legs are in a closed position, the first bracing member and the second bracing member are flexed in a mountain-fold shape via a pivot fitting between the column base members of the two adjacent legs, and the pivot fittings of both bracing members are arranged to overlap substantially in the front-rear direction Y.

[0014] The first and second brace members are formed by pivotally connecting a long arm and a short arm of different lengths using a pivot fitting so that they can be bent. The first brace member has the end of the long arm pivotally connected to the vicinity of the lower end of the column base member on one of the left and right legs, and the end of the short arm pivotally connected to a position a predetermined height (h) away from the lower end of the column base member on the other left and right leg. The second brace member is positioned in the opposite direction to the first brace member, with the end of the long arm pivotally connected to the vicinity of the lower end of the column base member on the other left and right leg, and the end of the short arm pivotally connected to a position a predetermined height (h) away from the lower end of the column base member on one of the left and right legs. The predetermined height (h) is configured to be a dimension corresponding to the difference in the length dimensions of the long arm and the short arm.

[0015] Furthermore, in the second means configured by the present invention, the top plate is supported by a pair of legs positioned spaced apart in the left-right X direction with respect to the left-right direction X and the front-back direction Y which are orthogonal on a plane, the top plate is connected so that it can change its posture between an unfolded position in which a pair of left and right divided top plates are positioned on the same plane and a folded position in which they are bent in the mountain-fold direction and positioned facing each other, the left and right legs are arranged to move so that they can change their posture between an open leg position in which they are spaced apart from each other and a closed leg position in which they are close together, and when both legs are in the open leg position the top plate This is a work platform configured to be deployed in an unfolded position and folded when the legs are closed, and to form an internal space between the legs in the open position, allowing workers to enter and exit below the top plate, and the left and right legs each consist of multiple ladder legs arranged in overlapping positions on the inside and outside facing the internal space, with the innermost ladder leg serving as the lower end ladder leg to move along the floor, and the outermost ladder leg serving as the upper end ladder leg to support the top plate, and the connected legs consist of the inner ladder legs The outer ladder legs are connected to the top plate so that they can slide vertically, thereby creating telescopic legs that retract when the outer ladder legs are moved downward and extend when they are moved upward. The inner and outer ladder legs are fixed together so that they can be engaged and disengaged, at least in the extended state, thereby supporting the top plate at a high position raised from a low position. Link devices are provided to connect the upper ladder legs on the left and right legs to the left and right top plates, respectively. The link device consists of a lower link member pivotally connected to the side of the upper ladder leg and a lower link member near the side edge in the middle of the top plate. The link mechanism is configured to be extendable and retractable by pivoting an upper link member to the lower surface of the main body, and by connecting both link members so as to be slidable in the longitudinal direction. When the legs are in the open position and the top plate is in the unfolded position, the middle part of the top plate is supported by the upper ladder leg via the retracted link mechanism. When the legs are in the closed position with the connected legs retracted and the top plate is in the folded position, the lower link member of the extended link mechanism is positioned along the side of the connected legs, and the upper link member is stored along the lower surface of the top plate.

[0016] In the illustrated embodiment, each of the multiple ladder legs constituting the linked legs is composed of a pair of parallel column legs spaced apart in the front-rear direction Y and extending vertically, and a rung installed on the pair of column legs. The lower link member of the link device has a base pivotally connected to the side surface of the column leg and an extension extending from the base towards the top plate via a bent portion, and the upper link member is slidably connected to the extension. When the linked legs are retracted to a closed leg position and the top plate is folded, the base of the lower link member extends from the side surface of the lower ladder leg to the side surface of the upper ladder leg in the linked legs, and the extension is raised upward via the bent portion, thereby storing the upper link member along the lower surface of the top plate. [Effects of the Invention]

[0017] According to the present invention, in a work device in which a top plate is supported by left and right legs, the top plate can be supported at selectable low and high positions, making it possible to provide a high-altitude work device that can accommodate work sites requiring work at different heights.

[0018] Furthermore, with the configuration that includes the bracing device, a structure is created in which the lower ladder legs of the left and right leg bodies are mutually connected and support each other, allowing the tabletop to be well supported while the lower ladder legs are stabilized.

[0019] Furthermore, with the configuration that includes a linking device, the connection structure between the top plate and the upper ladder legs can be made robust by a reinforcing structure formed by a frame with three sides of roughly equal length, which are roughly triangular in shape, using the column base material of the upper ladder legs, the top plate, and the linking device. [Brief explanation of the drawing]

[0020] [Figure 1] Regarding embodiments of the present invention, a high-altitude work device is shown with the legs in an open position and the top plate in an extended position. (A) is a perspective view with the top plate supported at a low position, and (B) is a perspective view with the top plate supported at a high position. [Figure 2]It is a perspective view showing the state where the connecting legs of each of the left and right leg bodies are extended. [Figure 3] Regarding the high-place work device with the leg body in the spread-leg posture and the top plate in the deployed posture, it shows the state where the top plate is supported at a low position by contracting the connecting legs. (A) is a front view, (B) is a side view, and (C) and (D) are enlarged views showing the connection parts of the left and right top plates. [Figure 4] Regarding the high-place work device with the leg body in the spread-leg posture and the top plate in the deployed posture, it shows the state where the top plate is supported at an intermediate position between the low position and the high position by moving the upper ladder leg of the ladder legs of the connecting legs upward. (A) is a front view, and (B) is a side view. [Figure 5] Regarding the high-place work device with the leg body in the spread-leg posture and the top plate in the deployed posture, it shows the state where the top plate is supported at a high position by extending the connecting legs. (A) is a front view, and (B) is a side view. [Figure 6] It shows the high-place work device. (A) is a front view, (B) is a front view showing the state where the lock mechanism of the link device is released, and (C) is a front view showing the state where the link device starts to extend. [Figure 7] Regarding the operation when folding the high-place work device, (A) is a front view showing the state during folding, and (B) is a front view showing the state where folding is completed. [Figure 8] It is a perspective view showing the state where the ladder legs of the connecting legs constituting the leg body are disassembled. [Figure 9] It is a cross-sectional view showing the state where the ladder legs of the connecting legs are disassembled. [Figure 10] It is a perspective view showing one column leg member of the disassembled ladder legs regarding the connecting legs. [Figure 11] It is a cross-sectional view showing the state where the ladder legs of the connecting legs constituting the leg body are overlapped with each other and slidably combined. [Figure 12] It is a perspective view showing one column leg member of the slidably combined ladder legs regarding the connecting legs. [Figure 13] It is a perspective view showing the state where the connecting legs constituting the leg body are contracted. [Figure 14] This is a perspective view showing the twin landing gear extended by moving the upper ladder leg upward. [Figure 15] This perspective view shows the twin landing gear in a state where it is further extended by moving the intermediate ladder leg upward along with the upper ladder leg. [Modes for carrying out the invention]

[0021] Preferred embodiments of the present invention will be described in detail below with reference to the drawings.

[0022] (Overall composition) As shown in Figures 1 to 7, the elevated work platform is constructed by supporting a top plate 2 with a pair of legs 1A and 1B that are spaced apart in the left-right direction X with respect to the left-right direction X and the front-back direction Y which are orthogonal to each other on a plane, and the top plate 2 is used as a work platform for working at heights.

[0023] The top plate body 2 is designed to allow for a change in orientation between an unfolded orientation P1 in which a pair of top plates 2A and 2B, divided in the left-right direction X, are positioned on the same plane, and a folded orientation P2 (see Figure 7(B)) in which they are bent in the mountain-fold direction and arranged facing each other.

[0024] Therefore, as shown in Figure 3, the top plates 2A and 2B are each composed of a support portion 2a located at the tail end in the left-right direction X and extending in the front-rear direction Y, and a floor portion 2c connected to the support portion 2a via a pivot portion 2b that is rotatable around a horizontal axis. The front ends of the floor portions 2c facing each other between the left and right top plates 2A and 2B are rotatably connected to each other by a connecting means 3. The connecting means 3 is equipped with a substantially upward-facing U-shaped connecting fitting 3a, and is located at both ends of the connecting fitting 3a, pivotally supporting the operating pieces 4, 4 provided at the front ends of the floor portion 2c so that they are rotatable around a horizontal axis.

[0025] The aforementioned leg bodies 1A and 1B are each composed of a series of legs that are extendable and retractable in the vertical direction, as described later, and are connected to support the support parts 2a of the top plates 2A and 2B from below.

[0026] The left and right leg bodies 1A and 1B are movable on the floor so as to be able to change their posture between an open-legged position L1, where they are separated from each other, and a closed-legged position L2, where they are close together (see Figure 7(B)). When both leg bodies 1A and 1B are in the open-legged position L1, the tabletop body 2 is in the unfolded position P1, and when they are in the closed-legged position L2, the tabletop body 2 is in the folded position P2.

[0027] To enable the orientation of the top plate 2 as described above, as shown in Figure 3, the connecting means 3 is provided with a rod 5 that passes through the connecting fitting 3a in the vertical direction and is movable up and down, and a pivot fitting 6 is fixed to the lower end of the rod 5. The pivot fitting 6 and the operating piece 4 are connected by a push-down link 7, and furthermore, the left and right leg bodies 1A and 1B and the pivot fitting 6 are connected by a push-up link 8.

[0028] Figures 3(A) and 3(B) and 6(A) show the state in which the tabletop 2 is in the unfolded position P1 by setting the legs 1A and 1B to the open position L1, and Figure 7(B) shows the state in which the tabletop 2 is in the folded position P2 by setting the legs 1A and 1B to the closed position L2. Figure 7(A) shows the state during the change of posture.

[0029] As shown in Figure 7(A), when the legs 1A and 1B are moved in a direction that brings them closer to each other, the top plates 2A and 2B are tilted in the mountain-fold direction, with the floor portions 2c and 2c rotating upward between the support portions 2a and 2a via the connecting means 3.

[0030] In this process, a quadrilateral link is formed by the leg body 1A (1B), the floor portion 2c, the push-down link 7, and the push-up link 8. The push-down link 7 lowers the pivot fitting 6 by the rotation of the operating piece 4. When the leg bodies 1A and 1B are moved toward each other, as shown in Figures 3(C) and 3(D), the floor portion 2c of the top plates 2A and 2B rotate upward with the pivot portion 2b as the fulcrum, and the push-up link 8 rotates upward away from the leg body 1A (1B), lifting the connecting means 3.

[0031] In this way, the movement of the legs 1A and 1B and the tilting of the top plates 2A and 2B are synchronized and interconnected. Then, as shown in Figure 7(B), when the device is in the folded position P2, the top plates 2A and 2B are positioned parallel to each other in a nearly vertical position on both sides of the connecting means 3, and the legs 1A and 1B are positioned on either side of them, facing each other and nearly parallel, thereby making the high-altitude work device compact when folded.

[0032] (Leg structure) As shown in Figures 1(A) and 2, the work platform is configured to form an internal space S on the underside of the top plate 2, between the left and right legs 1A and 1B, which are in an open-leg position L1, allowing a worker to enter and exit.

[0033] As shown in Figure 2, the left and right leg bodies 1A and 1B (hereinafter, when left and right are not distinguished, simply referred to as "leg body 1") each constitute a linked leg 10 by stacking multiple ladder legs 9 on the inner X1 and outer X2 sides facing the internal space S, respectively. In the illustrated embodiment, the linked leg 10 is composed of three ladder legs 9, and the innermost ladder leg will be referred to as the lower end ladder leg 9a, the middle ladder leg as the middle ladder leg 9b, and the outermost ladder leg as the upper end ladder leg 9c. However, in addition to the configuration shown, the linked leg 10 may also be composed by stacking two ladder legs 9 from the inside to the outside, or by stacking four or more ladder legs 9 from the inside to the outside. Hereafter, when the lower end ladder leg 9a, the middle ladder leg 9b, and the upper end ladder leg 9c are not distinguished, they will simply be referred to as "ladder leg 9".

[0034] In the illustrated embodiment, a caster device 11 is provided at the lower end of the lower ladder leg 9a, thereby enabling the leg body 1 to move in the left-right direction X on the floor. The upper end of the upper ladder leg 9c is connected to the lower side of the support portion 2a of the top plates 2A and 2B, thereby supporting the top plate body 2.

[0035] As shown in Figures 3 to 5, an outrigger device 12 can be attached to the inside of the lower ladder leg 9a. In the illustrated example, a ground wheel 13 is provided at the tip of the outrigger device 12's extended arm, and it travels on the floor together with the caster device 11.

[0036] The aforementioned linked legs 10 connect the outer ladder legs 9 to the overlapping inner ladder legs 9 so that they can slide vertically. In the illustrated embodiment, the intermediate ladder leg 9b is slidably connected to the lower end ladder leg 9a, and the upper end ladder leg 9c is slidably connected to the intermediate ladder leg 9b. As a result, the linked legs 10 constitute telescopic legs that contract when the outer ladder legs 9 are moved downward relative to the inner ladder legs 9, and extend when they are moved upward. Hereinafter, the linked legs 10 may be referred to as telescopic legs 10.

[0037] Incidentally, when the telescopic legs 10 are extended or retracted, a fixing device 23 is provided that detachably locks and secures the inner and outer ladder legs 9, 9 in that state, thereby enabling the tabletop body 2 to be supported at a high position raised from a low position. In the illustrated embodiment, the fixing device 23 is configured to lock and secure the inner and outer ladder legs 9, 9 even when the tabletop body 2 is supported at a low position L by retracting the telescopic legs 10, but it is sufficient if it locks and secures at least in the extended state.

[0038] In the illustrated embodiment in which the linked legs 10 are composed of three ladder legs, as shown in Figure 3, when the telescopic legs 10 of the leg body 1 are in the retracted state, that is, when the intermediate ladder leg 9b and the upper ladder leg 9c are all positioned at a predetermined low position and overlap with the lower ladder leg 9a, the top plate body 2 is supported at the lowest position (low position L).

[0039] From this state, as shown in Figure 4, when the upper ladder leg 9c is lifted and moved upward relative to the intermediate ladder leg 9b and locked in place by the fixing device 23, the telescopic leg 10 is extended, and the top plate body 2 is supported at an intermediate high position (intermediate position M). Although not shown in the figure, the upper ladder leg 9c can be moved upward in stages from the low position L shown in the figure to the intermediate position M, and is configured to be locked in place by the fixing device 23 at each stage.

[0040] Furthermore, as shown in Figure 5, by lifting the intermediate ladder leg 9b so that the upper ladder leg 9c, which has been moved upward relative to the lower ladder leg 9a, is raised and locked in place by the fixing device 23, the telescopic legs 10 extend further, reaching their maximum extension state, and the top plate body 2 is supported at the highest position (high position H). Although not shown in the figure, the intermediate ladder leg 9b can be moved upward in stages from the intermediate position M to the high position H, and is configured to be locked in place by the fixing device 23 at each stage.

[0041] (Structure of the telescopic legs) As shown in Figures 2 and 8 through 15, the ladder legs 9 consist of a pair of parallel column base members 14, 14 spaced apart in the front-to-back direction Y and extending vertically, and a rung 15 installed on the pair of column base members. The column base members 14 are equipped with a sliding mechanism that allows the inner and outer ladder legs (9a and 9b, 9b and 9c) to slide relative to each other, and the rung 15 provides a means for workers to ascend and descend between the floor (ground) and the top plate 2. It should be noted that the term "ladder" does not necessarily mean that its shape is strictly that of a ladder.

[0042] In the illustrated embodiment, when the telescopic legs 10 are extended, the inner ladder legs 9 are positioned lower and the outer ladder legs 9 are positioned upper. Therefore, when the legs are extended as described above, a worker can climb from the internal space S by ascending the innermost lower ladder leg 9a, then the intermediate ladder leg 9b positioned above and on the outside, and then the uppermost ladder leg 9c positioned further above and on the outside, thereby easily placing the soles of their feet on the rungs 15.

[0043] In this case, as shown in Figure 1, the top plate body 2 is provided with an opening 16 that connects the upper space and the space S, and this opening 16 is closed by a hatch 17 that can be opened and closed. Therefore, a worker ascending or descending the ladder legs 9 of the extended telescopic legs 10 can move between the upper space of the top plate body 2 and the space S by passing through the opening 16. The hatch 17, when closed, constitutes the floor surface of the top plate body 2.

[0044] The sliding mechanism that connects the inner and outer ladder legs 9 constituting the telescopic leg 10 so that they can slide against each other is constructed by extending rail sections 18 that protrude opposite each other along the column base member 14 and engaging the two rail sections 18, 18, thereby connecting the outer ladder leg 9 to the inner ladder leg 9 so that it can slide vertically and does not separate in the left-right direction X.

[0045] As shown in Figures 8 to 12, with respect to the inner side X1 facing the internal space S and the opposite outer side X2, the column base member 14 of the lower end ladder leg 9a is made of a molded material made by metal extrusion molding, and is composed of a groove-shaped member 14a (hereinafter also referred to as column base member 14a) into which the end of the rung 15 is fitted, and a pair of rail portions 18a, 18a are provided from the outer groove side wall of the groove-shaped member 14a toward the outer side X2.

[0046] The column base member 14 of the intermediate ladder leg 9b is made of a molded material made by metal extrusion molding, and is composed of a groove-shaped member 14b (hereinafter also referred to as column base member 14b) into which the rungs 15 are fitted. The groove-shaped member 14b is provided with a pair of rail sections 18f, 18f extending inward from the inner groove side wall toward the inside X1, and a pair of rail sections 18r, 18r extending outward from the outer groove side wall toward the outside X2.

[0047] Furthermore, the column base member 14 of the upper ladder leg 9c is made of a molded material made by metal extrusion molding, and is composed of a groove-shaped member 14c (hereinafter also referred to as column base member 14c) into which the end of the rung 15 is fitted, and a pair of rail sections 18c, 18c are provided from the inner groove side wall of the groove-shaped member 14c toward the inside X1.

[0048] As shown in Figures 9 to 12, the column base member 14a of the lower ladder leg 9a and the column base member 14b of the intermediate ladder leg 9b are slidably connected by fitting the rail sections 18a, 18a, which are spaced narrowly, into the rail sections 18f, 18f, which are spaced wide apart. At this time, the column base members 14a and 14b are engaged with each other in a way that allows for sliding movement and prevents separation in the left-right direction X by fitting the rib 19 provided at the tip of the rail section 18 of one column base member 14 into the retaining groove 20 formed in the other column base member 14.

[0049] Similarly, the column base member 14b of the intermediate ladder leg 9b and the column base member 14c of the upper ladder leg 9c are slidably connected by fitting the rail sections 18r, 18r, which are spaced narrowly, into the rail sections 18c, 18c, which are spaced wide apart. In this case, the column base members 14b and 14c are engaged with each other in a way that allows for slidable movement and prevents separation in the left-right direction X by fitting the rib 19 provided at the tip of the rail section 18 of one column base member 14 into the retaining groove 20 formed in the other column base member 14.

[0050] As a result, the ladder legs 9, 9, which are stacked from the inside out, have adjacent rungs 15, 15 spaced apart via the rail section 18, forming a spaced space Q (see Figure 11) into which a worker's hand can be inserted. Therefore, as described above, when a worker extends or retracts the telescopic legs 10 by manually lifting or lowering the ladder legs 9, they can do so by inserting their fingers through the spaced space Q to grasp the desired rung 15.

[0051] (Configuration of the biasing mechanism) The connected leg 10, which is formed by stacking multiple ladder legs 9, has a storage chamber R surrounded by the rail section 18 between the column leg members 14, 14 that are slidably connected to each other, and the biasing means 21 is housed inside the storage chamber R (see Figures 11 and 12). In the illustrated embodiment, the biasing means 21 is composed of a cylinder 22a and a rod 22b that are fitted together, as shown in Figure 8, and a known gas-type or spring-type damper 22 is used, which is biased in the extension direction from a contracted state by compressing gas or a spring between them. However, the biasing means 21 is not limited to a damper.

[0052] Between the column base member 14a of the lower ladder leg 9a and the column base member 14b of the intermediate ladder leg 9b, a storage chamber R is formed, enclosed by the groove side walls of the groove-shaped members 14a and 14b and the rail sections 18f and 18f. A damper 22 is housed in this storage chamber, and the lower end of the extended damper 22 is fixed near the lower end of the column base member 14a of the lower ladder leg 9a, while the upper end is fixed near the upper end of the column base member 14b of the intermediate ladder leg 9b.

[0053] Similarly, between the column base member 14b of the intermediate ladder leg 9b and the column base member 14c of the lower ladder leg 9c, a storage chamber R is formed, surrounded by the groove side walls of the groove-shaped members 14b and 14c and the rail sections 18c and 18c. A damper 22 is housed in this storage chamber, with the lower end of the extended damper 22 fixed near the lower end of the column base member 14b of the intermediate ladder leg 9b and the upper end fixed near the upper end of the column base member 14c of the upper ladder leg 9c.

[0054] Figure 8 shows the damper 22 in an extended state with the cylinder 22a facing upward and the rod 22b facing downward, but it may also be positioned upside down. In this configuration, the intermediate ladder leg 9b is lifted upward relative to the lower ladder leg 9a, and the upper ladder leg 9c is lifted upward relative to the intermediate ladder leg 9b, and both are supported by the damper 22.

[0055] Therefore, the intermediate ladder leg 9b and the upper ladder leg 9c can each move downward from the lifted state shown in the figure to a predetermined lower position so as to overlap with the lower ladder leg 9a, while the damper 22 is contracted against the biasing force. As a result, the telescopic leg 10 is brought into the contracted state shown in Figure 13.

[0056] (Fixing device) In this retracted state, the intermediate ladder leg 9b and the upper ladder leg 9c are biased upward by the damper 22, but are fixed by the fixing device 23 to prevent them from moving upward from a predetermined lower position. In the illustrated embodiment, the fixing device 23 is provided between the lower ladder leg 9a and the intermediate ladder leg 9b, and between the intermediate ladder leg 9b and the upper ladder leg 9.

[0057] As shown in Figures 9 to 12, the fixing device 23 is composed of a locking rod 24 that detachably locks and fixes adjacent ladder legs 9, 9 among the stacked ladder legs 9. The locking rod 24 has a rod body 24a that is positioned on a groove-shaped member of the column base member 14 of one ladder leg 9 and held so as to be movable in the front-rear direction Y, and a locking portion 24b formed by bending the rod body into a substantially U shape. The locking portion 24b is configured to detachably lock and fix the rails 18, 18 that are fitted into and overlap each other on the column base members 14, 14 of adjacent ladder legs 9, 9.

[0058] (Securing the intermediate ladder legs to the upper ladder legs) Between the column base member 14b of the intermediate ladder leg 9b and the column base member 14c of the upper ladder leg 9c, the rod body 24a is inserted through a retaining fitting 25 that is inserted into the groove-shaped member of the column base member 14b. This configuration allows the operator to hold the operating part 24c, formed by the bent portion between the rod body 24a and the locking part 24b, by hand and move it back and forth, thereby locking the locking part 24b by inserting it detachably into the locking holes 27 and 26 provided in the rail parts 18r and 18c, respectively, which are fitted together between the two column base members 14b and 14c.

[0059] Although not shown in the illustration, the locking hole 26 of the rail section 18c provided on the upper ladder leg 9c has two holes: a downward locking hole 26a located at a high position in the vertical direction of the rail section 18c, and an upward locking hole 26b located at a low position. In contrast, the locking hole 27 of the rail section 18r provided on the intermediate ladder leg 9b consists of a single hole located at a high position in the vertical direction of the rail section 18r.

[0060] When the upper ladder leg 9c is moved downward so that it overlaps with the intermediate ladder leg 9b (when the telescopic leg 10 is retracted), the locking holes 26a and 27 align and communicate between the rail sections 18c and 18r during downward movement, and the locking rod 24 is locked by inserting the locking portion 24b of the locking rod 24 through it.

[0061] In the illustrated embodiment, the locking rod 24 is biased to advance the locking portion 24b by providing a spring 28 on the rod body 24a. Therefore, when the operator pulls the operating portion 24c to retract the locking rod 24, the locking portion 24b is pulled out from the locking holes 27 and 26.

[0062] As a result, the lock is released and the ladder leg 9c is moved upward relative to the intermediate ladder leg 9b. When the ladder leg 9c moves upward, the locking rod 24 is biased in the forward direction by the spring 28, so the locking portion 24b at its tip slides in contact with the outer surface of the rail portion 18c as it moves upward, maintaining the unlocked state.

[0063] Then, when the upward-moving rail section 18c reaches the position of the locking hole 26b located at a lower position on the rail section 18r and communicates with the locking hole 27, the biasing force of the spring 28 causes the locking section 24b to automatically advance and be inserted into both locking holes 26b and 27.

[0064] Furthermore, it is preferable that the retaining fitting 25 is configured such that the axis of the locking portion 24b is positioned and held toward the locking holes 26 and 27 by providing a guide retaining portion 25a that inserts and holds the locking portion 24b.

[0065] As described above, when the upper ladder leg 9c is moved downward to a predetermined lower position so that it overlaps with the intermediate ladder leg 9b (with the telescopic leg 10 retracted as shown in Figure 13), the locking part 24b is inserted through the locking hole 26a for downward movement of the rail part 18c and the locking hole 27 of the rail part 18r, locking and fixing both rail parts 18c and 18r so that they cannot slide. As a result, the upper ladder leg 9c is fixed in the predetermined lower position after being moved downward against the biasing force of the damper 22.

[0066] When the locking mechanism 24b is released and the upper ladder leg 9c is lifted to a predetermined upper position (as shown in Figure 14), the locking hole 26b for upward movement of the rail section 18c aligns with the locking hole 26 of the rail section 18r, and the locking mechanism 24b is inserted through both holes 26b and 27 to lock and fix both rail sections 18c and 18r so that they cannot slide. As a result, the top plate body 2 is supported at an intermediate position M via the upper ladder leg 9c that has been moved upward.

[0067] Figure 14 shows the upper ladder leg 9c raised to its highest position, but as described above, it is preferable to configure the top plate 2 to be supported in stages between a low position L and an intermediate position M. In this case, the rail section 18c is provided with a plurality of locking holes 26 at a predetermined interval between the locking hole 26a for downward movement and the locking hole 26b for upward movement, and the locking holes 26 are connected to the locking holes 27 at the desired height position, and the locking part 24b is inserted through them, thereby locking and fixing both rail sections 18c and 18r so that they cannot slide.

[0068] Furthermore, when lifting the upper ladder leg 9c, the damper 22 applies an upward biasing force, which reduces the lifting force required of the worker even when the top plate 2 is a heavy object.

[0069] (Securing the lower ladder leg to the intermediate ladder leg) The configuration of the fixing device 23 and locking holes 26, 27 provided on the column base member 14a of the lower ladder leg 9a and the column base member 14b of the intermediate ladder leg 9b is the same as the configuration of the fixing device 23 and locking holes 26, 27 provided on the column base member 14b of the intermediate ladder leg 9b and the column base member 14c of the upper ladder leg 9c described above. Therefore, identical components are indicated by the same reference numerals, and redundant explanations are omitted, relying on the explanations above.

[0070] As described above, when the upper ladder leg 9c is lifted to a predetermined upper position and moved upward (as shown in Figure 14), the column base member 14a of the lower ladder leg 9a and the column base member 9b of the intermediate ladder leg 9b are connected when the locking hole 26a for downward movement of the rail section 18f aligns with the locking hole 27 of the rail section 18a, and the locking portion 24b of the locking rod 24 is inserted through both holes to lock and fix them in place.

[0071] From this state, after releasing the locking mechanism, as shown in Figure 15, when the intermediate ladder leg 9b is lifted and moved upward to a predetermined upper position, the locking hole 26b for upward movement of the rail section 18f aligns with the locking hole 27 of the rail section 18a between the column base member 14a of the lower ladder leg 9a and the column base member 9b of the intermediate ladder leg 9b. By inserting the locking portion 24b of the locking rod 24 through both holes, the locking mechanism is secured. As a result, the top plate body 2 is supported at a raised position H via the upper ladder leg 9c and the intermediate ladder leg 9b, which have been moved upward.

[0072] When lifting the intermediate ladder leg 9b, the upward biasing force from the damper 22 is applied, reducing the lifting force required by the worker.

[0073] In this case as well, Figure 15 shows the intermediate ladder leg 9b raised to its highest position, but it is preferable to configure the top plate body 2 to be supported in stages between the intermediate position M and the high position H, similar to the case of the upper end ladder leg 9c described above. In this case, the rail portion 18f of the column base member 14b is provided with a plurality of locking holes 26 at a predetermined interval between the locking holes 26a for downward movement and the locking holes 26b for upward movement, and the rail portions 18f and 18a can be locked and fixed so as not to slide by connecting the locking holes 26 to the locking holes 27 at the desired height position and inserting the locking portion 24b.

[0074] (Relationship between biasing means and fixing device) In the illustrated embodiment described above, since a biasing means 21 such as a damper 22 is provided, when the telescopic leg 10 is in the retracted state, the intermediate ladder leg 9b and the upper ladder leg 9c, which are superimposed on the lower ladder leg 9a, may unexpectedly rise due to the upward biasing force received from the biasing means 21. For this reason, as described above, the fixing device 23 is configured such that the locking portion 24b of the locking rod 24 is inserted into the locking hole 26a and the locking hole 27 for downward movement, thereby locking and fixing the upper ladder leg 9c to the intermediate ladder leg 9b, and locking and fixing the intermediate ladder leg 9b to the lower ladder leg 9a.

[0075] However, if the high-altitude work device of the present invention does not require the lifting force of the worker to be reduced as described above, the biasing means 21 may not be provided. In this case, when the telescopic legs 10 are in the retracted state, the intermediate ladder legs 9b and upper ladder legs 9c, which are superimposed on the lower ladder legs 9a, are not in danger of rising on their own, so it is sufficient to provide a stopper or the like to receive them in the lowered position, and it is not necessary to provide a locking hole 26a for lowered movement for inserting and locking the locking portion 24b of the fixing device 13.

[0076] In short, the fixing device 13 only needs to be able to detachably lock and fix the column base members of both ladder legs when the telescopic legs 10 are extended, that is, when they are moved upward, the upper end ladder leg 9c and the intermediate ladder leg 9b, and the intermediate ladder leg 9b and the lower end ladder leg 9a, when they are moved upward. Furthermore, if the biasing means 21 is equipped as described above, it is preferable to provide a locking hole 26a for downward movement to lock and fix the telescopic legs 10 in the retracted state, but if the biasing means 21 is not equipped, it is not necessary to provide a locking hole 26a for downward movement.

[0077] (Brace device) As shown in Figures 1 to 7, the work platform is equipped with a bracing device 29 that connects the opposing column base members 14, 14 of the lower ladder legs 9a, 9a between the left and right leg bodies 1A, 1B.

[0078] The brace device 29 is composed of two sets of brace devices: a front brace device 29A located at the front and connecting opposing column base members 14, 14 in the front-rear direction Y, and a rear brace device 29B located at the rear and connecting opposing column base members 14, 14. The internal space S is formed between the two brace devices 29A and 29B. Since the front brace device 29A and the rear brace device 29B have the same configuration, they will be simply referred to as the brace device 29 in the following description unless otherwise distinguished.

[0079] As shown in Figures 1 to 6, the brace device 29 is configured to unfold when the left and right legs 1A and 1B are in an open position L1, thereby mutually supporting the lower ladder legs 9a, 9a between the two legs 1A and 1B, and to bend and fold when the legs are in a closed position L2. It is composed of a first brace member 30a and a second brace member 30b that intersect in an approximately X shape.

[0080] The first brace member 30a is positioned facing the outside of the internal space S, and the second brace member 30b is positioned facing the inside of the internal space S. In this case, the first brace member 30a and the second brace member 30b are constructed by pivotally connecting a long arm 31a and a short arm 31b, which have different lengths, with a pivot fitting 32 so that they can be bent.

[0081] Therefore, the first brace member 30a and the second brace member 30b are arranged to intersect as shown in the figure, thereby forming a brace device 29.

[0082] As shown in Figures 2 and 6, between the left and right leg bodies 1A and 1B, the first brace member 30a is pivotally connected via a bracket 33a to the vicinity of the lower end of the column base member 14 of the lower ladder leg 9a on the left leg body 1A, and via a bracket 34a to the end of the short arm 31b on the right leg body 1B at a position a predetermined height h away from the lower end of the column base member 14 of the lower ladder leg 9a.

[0083] The second brace member 30b is positioned opposite to the first brace member 30a, with the end of the long arm 31a pivotally connected via a bracket 33b to the vicinity of the lower end of the column base member 14 of the lower ladder leg 9a on the right leg body 1B, and the end of the short arm 31b pivotally connected via a bracket 34b to a position a predetermined height h away from the lower end of the column base member 14 of the lower ladder leg 9a on the left leg body 1A.

[0084] As a result, the first brace member 30a and the second brace member 30b intersect each other at their long arms 31a, 31a, and the pivot fitting 32 is positioned above the intersection.

[0085] Therefore, when the left and right legs 1A and 1B are in a spread-leg position L1, the first brace member 30a is tilted upward from the column base member 14 of the left leg 1A toward the column base member 14 of the right leg 1B, and the second brace member 30b is tilted upward from the right leg 1B toward the column base member 14 of the left leg 1A, crossing each other and supporting the column base members 14, 14 of both legs 1A and 1B.

[0086] When the top plate 2 of the high-altitude work device is used at a high position H, the left and right legs 1A and 1B are in an open position L1, and the telescopic legs 10 are extended. As shown in Figures 1(B), 2 and 5, the lower ladder legs 9a and the intermediate ladder legs 9b, and the intermediate ladder legs 9b and the upper ladder legs 9c are connected only by the overlapping rail sections 18, which can cause swaying and make the device unstable. In particular, the upper ladder legs 9c are fixed to the top plate 2 and are therefore relatively strong, but the lowest-positioned lower ladder legs 9a are unstable. For this reason, a brace device 29 is provided to connect the lower ladder legs 9a, 9a of the left and right legs 1A and 1B to each other, creating a structure in which they support each other, thereby stabilizing the lower ladder legs 9a, 9a and providing good support for the top plate 2. Incidentally, regarding the oscillation in the longitudinal direction Y, since the first brace material 30a and the second brace material 30b intersect in close proximity in each of the brace devices 29A and 29B, oscillation can be effectively prevented.

[0087] By extension, when the telescopic legs 10 are extended to support the top plate body 2 at a high position H, and then the intermediate ladder legs 9b and upper ladder legs 9c are moved downward toward the lower ladder legs 9a to overlap them, thereby retracting the telescopic legs 10, the brace device 29 is provided on the innermost lower ladder leg 9a. Therefore, the downward movement of the intermediate ladder legs 9b and upper ladder legs 9c is not obstructed, and the telescopic legs 10 can be retracted appropriately.

[0088] Then, when the left and right leg bodies 1A and 1B are set to the closed leg position L2 and the top plate body 2 is set to the folded position P2, as shown in Figure 7(A), as the left and right leg bodies 1A and 1B move toward each other, each brace member 30 of the brace device 29 is folded by bending the long arm 31a and the short arm 31b via the pivot fitting 32.

[0089] As described above, the first brace member 30a and the second brace member 30b are pivotally connected at a predetermined height h away from the lower end of the column base member 14 of the lower end ladder leg 9a, and this predetermined height h is formed to correspond to the difference in length between the long arm 31a and the short arm 31b.

[0090] Therefore, as shown in Figure 7(B), when the left and right leg bodies 1A and 1B are in a completely closed position L2 and the top plate body 2 is in a completely folded position P2, the first brace member 30a and the second brace member 30b are preferably bent in a mountain fold shape, and the pivot fitting 32 bent between the two brace members 30a and 30b can be positioned so as to overlap almost in the front-to-back direction Y, thereby allowing the long arm 31a and the short arm 31b to be folded properly.

[0091] (Link device) As shown in Figures 1 and 2, and Figures 6 and 7, the column base members 14 of the upper ladder legs 9c, 9c of the left and right leg bodies 1A, 1B, and the left and right top plates 2A, 2B are connected by link devices 34. In other words, four link devices 34 with the same configuration are provided on each of the four column base members 14.

[0092] The linkage device 34 consists of a lower link member 35 located in the vertical middle of the column base member 14 at the upper end ladder leg 9c and pivotally connected to the outer side surface via a bracket 37a, and an upper link member 36 pivotally connected to the lower surface near the side edge in the horizontal X middle of the top plate 2A (2B) via a bracket 37b.

[0093] As shown in Figure 6, the lower link member 35 comprises a base 35a pivotally connected to the side surface of the column base member 14, a bent portion 35b formed by bending the tip of the base 35a toward the top plate 2A (2B), and an extension portion 35c extending from the bent portion 35b toward the top plate 2A (2B). In contrast, the upper link member 36 is slidably connected to the extension portion 35c.

[0094] In the illustrated embodiment, an extension 35c made of a rod is slidably inserted into an upper link member 36 formed of a pipe. As a result, as shown in Figure 6(A), when the left and right legs 1A and 1B are in an open position L1 and the top plate 2 is in an unfolded position P1, the ends of both link members 35 and 36 abut together, causing the link device 34 to be in a contracted state. Then, from this state, when the left and right legs 1A and 1B are in a closed position L2 and the top plate 2 is in a folded position P2, the upper link member 36 slides along the extension 35c and moves away from the lower link member 34, causing the link device 34 to be in an extended state.

[0095] Therefore, when the link device 34 is in a contracted state and the ends of the lower link member 35 and the upper link member 36 are brought together, a locking mechanism 38 is provided that locks the abutting ends of both link members 35 and 36 so that they can be engaged and disengaged from each other.

[0096] As shown in Figures 6(A) and 6(B), the locking mechanism 38 consists of a lever 38a pivotably supported on one end of the butt joint ends of the two link members 35 (the end of the lower link member 35 in the illustrated embodiment), a locking member 38b consisting of a ring fitting or the like that is pivotably attached to the lever 38a, and a locking member 38c such as a hook fixed to the other end (the end of the upper link member 36 in the illustrated embodiment).

[0097] The lever 38a is rotatable between a locked position along the end of the lower link member 35 shown in Figure 6(A) and an unlocked position away from the end of the lower link member 35 shown in Figure 6(B), and is configured to allow the locking member 38b to be detachably locked to the locked member 38c when in the unlocked position.

[0098] Therefore, after rotating the lever 38a to the unlock position to engage the locking member 38b with the locked member 38c, rotating the lever 38a to the locked position locks the abutting ends of the lower link member 35 and the upper link member 36 so that they cannot separate. From this state, rotating the lever 38a to the unlock position again allows the locking member 38b to be released from the locked member 38c, thereby unlocking the abutting ends so that they can separate.

[0099] When the top plate 2 of the high-altitude work device is used at a high position H, the left and right legs 1A and 1B are in an open position L1, and the telescopic legs 10 are extended. As shown in Figures 1(B), 2, and 5, the lower ladder legs 9a and the intermediate ladder legs 9b, and the intermediate ladder legs 9b and the upper ladder legs 9c are connected only by the overlapping portions of the rail sections 18, which can cause swaying and make the device unstable. As mentioned above, the lower ladder legs 9a are reinforced by a brace device 29. Therefore, the link device 34 reinforces the upper ladder legs 9c that support the top plate 2.

[0100] In this configuration, the link device 34 contracts the lower link member 35 and the upper link member 36, locking the locking mechanism 37, and connects the vertically intermediate portion of the column base member 14 at the upper ladder leg 9c to the horizontally intermediate portion of the top plate 2A (2B). This forms a relatively large frame with three sides of approximately equal length, which are roughly triangular in shape, using the column base member 14, the top plate 2A (2B), and the link device 34. Consequently, this reinforcing structure makes the connection between the top plate body 2 and the upper ladder leg 9c robust.

[0101] Incidentally, when the telescopic legs 10 are extended to support the top plate body 2 at a high position H, and then the intermediate ladder legs 9b and the upper ladder legs 9c are moved downward toward the lower ladder legs 9a to overlap them, thereby retracting the telescopic legs 10, the link device 34 pivotally connects the lower link member 35 to the outer side surface of the column leg member 14 on the upper ladder leg 9c. Therefore, it does not obstruct the downward movement of the upper ladder legs 9c and the intermediate ladder legs 9b, and the telescopic legs 10 can be retracted appropriately.

[0102] By the way, when the left and right legs 1A and 1B are in the closed position L2 and the top plate 2 is in the folded position P2, as shown in Figures 6(B) and 6(C), the locking mechanism 37 is unlocked, and then as shown in Figure 7, the left and right legs 1A and 1B are moved in the direction of proximity.

[0103] In this case, as shown in Figure 7(A), the lower link member 35 and the upper link member 36 rotate upward while extending from each other. Then, as shown in Figure 7(B), when the left and right leg bodies 1A and 1B are in a completely closed position L2 and the top plate body 2 is in a completely folded position P2, the base 35a of the lower link member 35 passes from the outer surface of the column base member 14 of the upper ladder leg 9c, through the outer surface of the column base member 14 of the intermediate ladder leg 9b, to the outer surface of the column base member 14 of the lower ladder leg 9a, and from there the extension 35c is raised upward via the bending portion 35b, thereby allowing the upper link member 36 to be conveniently stored along the lower surface of the top plate 2A (2B), enabling a compact folded state. [Explanation of Symbols]

[0104] X Left / right direction X1 Inside X2 outside Y (forward / backward direction) P1 Deployment posture P2 Folding position PM intermediate posture L1 Leg-spread position L2 Closed leg posture S interior space L low position M intermediate position H high position Q Separate space R storage room 1A, 1B Legs 2 Top panel 2A, 2B Top 2a Support part 2b Pivotal connection 2c floor part 3 Connection means 3a Connecting fittings 4 Actuating piece 5 rods 6. Pivoting fittings 7. Click the link 8 Oshiage Link 9 ladder legs 9a Bottom side ladder leg 9b Intermediate ladder leg 9c Upper end ladder leg 10-section landing gear (extendable legs) 11 Caster device 12 Outrigger device 13 Grounding wheels 14 Pillar base material 14a, 14b, 14c channel-shaped members 15 Stepping stones 16 Opening 17 Hatch 18, 18a, 18f, 18r, 18c Rail section 19 Ribs 20 Retaining groove 21. Biasing means 22 dampers 22a 1 / 2 22b Rod 23 Fixation device 24 Locking rod 24a Rod body 24b Lock section 24c Control unit 25 Retaining hardware 25a Guide holding section 26, 27 Locking holes 26a Locking hole for downward movement 26b Locking hole for upward movement 28 Springs 29, 29A, 29B Brace device 30a First brace material 30b Second brace material 31a Long arm 31b Short Arm 32 Pivoting fittings 33a, 33b, 34a, 34b brackets 34 Link device 35 Lower link material 35a base 35b Refractive section 35c extension 36 Upper link material 37a, 37b brackets 38 Locking mechanism 38a Lever 38b Locking member 38c Locked member

Claims

1. With respect to the left-right direction X and the front-back direction Y, which are orthogonal to each other on a plane, the top plate is supported by a pair of legs that are spaced apart in the left-right X direction. The top plate body (2) is connected such that it can change orientation between an unfolded position (P1) in which a pair of top plates (2A) and (2B), which are divided into left and right halves, are arranged on the same plane, and a folded position (P2) in which they are bent in the direction of a mountain fold and arranged facing each other. The left and right legs (1A) and (1B) are arranged to be movable so as to be able to change their posture between an open leg position (L1) where they are separated from each other and a closed leg position (L2) where they are close together. The system is configured such that when both legs are in the open leg position (L1), the top plate is in an unfolded position (P1), and when they are in the closed leg position (L2), the top plate is in a folded position (P2). An internal space (S) is formed between the legs (1A) and (1B) in the open leg position (L1) on the underside of the top plate (2) so that a worker can enter and exit. The left and right leg bodies (1A) and (1B) respectively form a connected leg (10) by a plurality of ladder legs (9) arranged in overlapping positions on the inside and outside facing the internal space (S), with the innermost ladder leg serving as the lower end ladder leg (9a) to allow movement on the floor surface, and the outermost ladder leg serving as the upper end ladder leg (9c) to support the top plate body (2). The aforementioned connected legs (10) are configured to be telescopic legs that retract when the outer ladder legs are moved downward and extend when they are moved upward, by connecting the outer ladder legs to the inner ladder legs so that they can slide vertically. The inner and outer ladder legs are fixed detachably in at least the extended state, thereby supporting the top plate body at a high position raised from a low position. Brace devices (29) are provided on both sides in the front-rear direction Y of the internal space (S) to connect the lower ladder legs (9a) (9a) of the left and right leg bodies (1A) (1B) to each other. The brace device (29) is configured to extend when the left and right legs are in an open position (L1) to mutually support the lower end ladder legs (9a) (9a) of both legs, and to fold when the legs are in a closed position (L2) by bending.

2. Each of the multiple ladder legs (9) constituting the aforementioned linked legs (10) is composed of a pair of parallel column base members (14) (14) spaced apart in the front-rear direction Y and extending vertically, and a rung (15) installed on the pair of column base members. The aerial work device according to claim 1, characterized in that the brace device (29) is composed of a brace member (30) that connects column base members (14) (14) that are opposite to each other between the lower end ladder legs (9a) (9a) of the left and right leg bodies (1A) (1B).

3. The brace devices (29A) and (29B) arranged on both sides in the front-rear direction Y of the internal space (S) each comprise a first brace member (30a) and a second brace member (30b) that are flexible from an extended state via a pivot fitting (32), Between one column base member (14) and the other column base member (14) facing each other in the left-right direction X, the first brace member (30a) and the second brace member (30b) are arranged to cross each other. When the left and right legs (1A) and (1B) are in an open-leg position (L1), the first brace member (30a) in the extended state is inclined upward from the column base of one leg (1A) toward the column base of the other leg (1B), and the second brace member (30b) in the extended state is inclined downward from the column base of one leg (1A) toward the column base of the other leg, and the two columns are configured to support each other. The high-altitude work device according to claim 2, characterized in that when the left and right leg bodies (1A) (1B) are in a closed position, the first brace member (30a) and the second brace member (30b) are bent in a mountain-fold shape between the column base members of the two adjacent leg bodies via a pivot fitting (32), and the pivot fittings (32) (32) of both brace members are arranged to overlap substantially in the front-rear direction Y.

4. The first brace member (30a) and the second brace member (30b) are formed by pivotally connecting a long arm (31a) and a short arm (31b) of different lengths with a pivot fitting (32) so that they can be bent. The first brace member (30a) has the end of the long arm (31a) pivotally connected to the vicinity of the lower end of the column base member (14) on one of the left or right legs (1A), and the end of the short arm (31b) pivotally connected to a position a predetermined height (h) away from the lower end of the column base member (14) on the other left or right leg (1B). The second brace member (30b) is positioned opposite to the first brace member (30a), with the end of the long arm (31a) pivotally connected to the vicinity of the lower end of the column base member (14) on the other left or right leg (1B), and the end of the short arm (31b) pivotally connected to a position a predetermined height (h) away from the lower end of the column base member (14) on one of the left or right leg (1A). The elevated work device according to claim 3, characterized in that the predetermined height (h) is configured to be a dimension corresponding to the difference in length between the long arm (31a) and the short arm (31b).

5. With respect to the left-right direction X and the front-back direction Y, which are orthogonal to each other on a plane, the top plate is supported by a pair of legs that are spaced apart in the left-right X direction. The top plate body (2) is connected such that it can change orientation between an unfolded position (P1) in which a pair of top plates (2A) and (2B), which are divided into left and right halves, are arranged on the same plane, and a folded position (P2) in which they are bent in the direction of a mountain fold and arranged facing each other. The left and right legs (1A) and (1B) are arranged to be movable so as to be able to change their posture between an open leg position (L1) where they are separated from each other and a closed leg position (L2) where they are close together. The system is configured such that when both legs are in the open leg position (L1), the top plate is in an unfolded position (P1), and when they are in the closed leg position (L2), the top plate is in a folded position (P2). An internal space (S) is formed between the legs in the open leg position (L1) on the underside of the top plate, allowing a worker to enter and exit. The left and right leg bodies (1A) and (1B) respectively form a connected leg (10) by a plurality of ladder legs (9) arranged in overlapping positions on the inside and outside facing the internal space (S), with the innermost ladder leg serving as the lower end ladder leg (9a) to allow movement on the floor surface, and the outermost ladder leg serving as the upper end ladder leg (9c) to support the top plate. The aforementioned connected legs (10) are configured to be telescopic legs that retract when the outer ladder legs are moved downward and extend when they are moved upward, by connecting the outer ladder legs to the inner ladder legs so that they can slide vertically. The inner and outer ladder legs (9)(9) are fixed detachably in at least the extended state, thereby supporting the top plate body (2) at a high position raised from a low position. Link devices (34) are provided to connect the upper ladder legs (9c)(9c) of the left and right leg bodies (1A)(1B) to the left and right top plates (2A)(2B), respectively. The link device (34) is composed of a lower link member (35) pivotally connected to the side of the upper ladder leg (9c) and an upper link member (36) pivotally connected to the lower surface near the side edge in the middle of the top plate, and the link device is configured to be extendable and retractable by connecting both link members so that they can slide in the longitudinal direction. When the legs are in the open position (L1) and the tabletop is in the extended position (P1), the middle part of the tabletop is supported by the upper ladder legs (9c) via the retracted link device (34). A high-altitude work device characterized in that, when the linked legs (10) are retracted and the leg body is in a closed position (L2) and the top plate body is in a folded position (P2), the lower link member (35) of the extended link device (34) is positioned along the side of the linked legs (10) and the upper link member (36) is stored along the underside of the top plate body.

6. Each of the multiple ladder legs (9) constituting the aforementioned linked legs (10) is composed of a pair of parallel column base members (14) (14) spaced apart in the front-rear direction Y and extending vertically, and a rung (15) installed on the pair of column base members. The lower link member (35) of the link device (34) comprises a base (35a) pivotally connected to the side surface of the column base member (14), and an extension (35c) extending from the base towards the top plate via a bent portion (35b), with the upper link member (36) slidably connected to the extension (35c). The high-altitude work device according to claim 5, characterized in that when the linked legs (10) are retracted to a closed leg position (L2) and the top plate is folded to a folded position (P2), the base (35a) of the lower link member (35) extends from the side surface of the lower ladder leg (9a) of the linked legs to the side surface of the upper ladder leg (9c), and the extension (35c) is raised upward via the bending portion (35b), thereby causing the upper link member (36) to be stored along the lower surface of the top plate.

Images