Stepladder

Abstract

To provide a stepladder that can reduce the burden on workers in installation work (opening / closing legs) and improve efficiency.SOLUTION: A stepladder includes a moving device 5 having crawlers 52 at the bottom end of each support 4 that can move in a forward and backward direction, and a limiter device 6 that stops the moving device 5 when front and rear legs 2 are in an open and closed state, in which the moving device 5 has drive means that drives the crawlers 52 and an open / close switch S1 that activates the drive means, and is equipped with a limiter device 6 that stops the drive means of the moving device 5 when the front and rear legs 2 are in an open and closed state, wherein operating the open / close switch S1 causes the front and rear moving devices 5 to move in directions away from each other to open the legs 2, and causes the front and rear moving devices 5 to move in directions toward each other to close the legs 2.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a stepladder that can be set up in a stable state by automatically opening its legs with the operation of a switch when placed at an installation location. [Background technology]

[0002] When using a stepladder, the worker must first check that each leg (support) is stable and can be set up at the installation location, and then open the legs from the closed position and set it up by himself. For relatively small stepladders, setting up the stepladder is not a burden, but for larger stepladders, the setting up process can be quite burdensome.

[0003] Furthermore, if the stepladder is installed on a slope, uneven surface, or if there are obstacles, it takes time to ensure that the stepladder is level, which reduces work efficiency.

[0004] In particular, when performing wiring work, for example, workers must climb on and off the ladder many times, and each time they must close and open the ladder's legs, making installation work a significant burden.

[0005] Patent Document 1 describes a stepladder in which each leg can be extended or retracted to ensure that the stepladder is level after installation. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2022-45977 Summary of the Invention [Problem to be solved by the invention]

[0007] In the stepladder described in Patent Document 1, the extension and retraction of each leg can be remotely controlled using an extendable leg device to ensure horizontality, and it is possible to visually check whether the extension and retraction state of the support poles is locked or unlocked, thereby making the installation work more efficient and confirming safety.

[0008] However, even with the stepladder described in Patent Document 1, the opening and closing of the legs involved in setting up the stepladder still remains the same as before, and the worker must do it by himself, which means that there is a problem that it is not possible to reduce the workload or improve efficiency.

[0009] Therefore, the object of this invention is to provide a stepladder that has crawlers at the bottom end of each support pole and that can be driven by operating a switch to open and close the legs of the stepladder, thereby reducing the burden of installation work and improving efficiency. [Means for solving the problem]

[0010] In order to solve the above problem, the invention of claim 1 is a stepladder comprising ladder-shaped legs with several steps between two supports, the two legs facing each other front to back and connected at the top via a hinge, a moving device having crawlers at the lower end of each support that can move in a front to back direction, and a limiter device that stops the moving device when the front and rear legs reach an open leg state and a closed leg state, the moving device having a drive means for driving the crawlers and a switch for activating the drive means, and a limiter device that stops the drive means of the moving device when the front and rear legs reach an open leg state and a closed leg state, and by operating the switch, the front and rear moving devices move away from each other to open the legs, and the front and rear moving devices move towards each other to close the legs.

[0011] The invention of claim 2 is characterized in that the stepladder described in claim 1 is provided with an extension mechanism provided on each of the supports that extends or retracts the length of each, and a horizontal sensor provided on the leg that detects the degree of horizontality, and the horizontal state is ensured by adjusting the length of a specified support based on the detection result of the horizontal sensor. [Effects of the Invention]

[0012] According to the invention of claim 1, a moving device having crawlers is provided at the lower end of each support pillar, and by driving the crawlers by operating a switch, the legs of the stepladder can be opened and closed automatically, eliminating the need for the worker to open and close the legs of the stepladder by themselves, thereby reducing the workload.

[0013] This is particularly effective for large stepladders, when the legs of the stepladder must be opened and closed repeatedly, such as when performing wiring work.

[0014] Moreover, since the moving device is provided at the lower end of the stepladder's support and uses crawlers for the moving device, the moving device can move even if the installation surface is uneven or not slippery, and it can be used regardless of the condition of the installation surface.

[0015] According to the invention of claim 2, each support pole is equipped with an extension mechanism and a spirit level (level sensor) is provided, which senses the inclination state (degree of horizontality) of the stepladder and automatically ensures a horizontal state, allowing work on the stepladder to be done safely. [Brief explanation of the drawings]

[0016] [Figure 1] 2 to 7 show a stepladder according to an embodiment of the present invention, and this figure is a perspective view showing the stepladder in an upright position with its legs spread apart. [Figure 2] FIG. 10 is a side view showing the legs in an upright position. [Figure 3] FIG. 10 is a side view showing the legs in a closed position. [Figure 4] 5 shows an enlarged view of the moving device, and this figure is a schematic side view of the main part when the legs are closed and the support column is vertical. [Figure 5] FIG. 10 is a schematic side view of the main part when the legs are spread and the support column is tilted. [Figure 6] 7 shows an enlarged view of the extension mechanism and the anti-slip mechanism, and this figure is a schematic front view of the main parts when the support pole is retracted and the anti-slip mechanism is not activated. [Figure 7] FIG. 10 is a schematic front view of the main parts with the support rod extended and the anti-slip mechanism activated. DETAILED DESCRIPTION OF THE INVENTION

[0017] The present invention will be described below based on the illustrated embodiments.

[0018] (Embodiment) 1 to 3 show the entire stepladder 1 according to this embodiment, with Fig. 1 being a perspective view of the stepladder 1 in an open-legged state, Fig. 2 being a side view of the stepladder 1 in an open-legged state, and Fig. 3 being a side view of the stepladder 1 in a closed-legged state. Note that the directions of the stepladder 1 are indicated by the arrows in Fig. 1 (F is forward, B is backward, R is right, and L is left).

[0019] The stepladder 1 is composed of two ladder-like legs 2 connected at the top by a hinge 3.

[0020] The legs 2 are provided with four step bars 41 that are hung vertically at a predetermined height between two left and right support posts 4, the uppermost step bar being a top plate 41U, and a hinge 3 is provided at the joint between the two top plates 41U.

[0021] The upper ends of the left and right support posts 4 of the front leg 2 are connected by a U-shaped upper frame 4a, which is used by workers as a handrail when climbing up the stepladder 1, or to hang tools, etc.

[0022] At the lower end of each support column 4, a moving device 5 is provided for moving the lower end of the support column 4 back and forth.

[0023] The moving device 5 comprises a housing 51, crawlers 52 provided on the left and right sides of the housing 51, and a drive motor (not shown) provided inside the housing 51 for driving the crawlers 51, and the housing 51 is supported at the lower end of the support 4 so that it can swing freely forward and backward and up and down.

[0024] The moving device 5 starts a drive motor (not shown) by operating an open / close switch S1 provided on the support 4, and drives each crawler 52. When the crawler 52 is driven, the lower end of each support 4 moves forward or backward, and the legs 2 open or close in the leg opening or closing direction.

[0025] That is, when the stepladder 1 is in the closed leg state, turning on the "open" switch S1 causes the movement devices 5 of the two front legs 2 to move forward and the movement device 5 of the rear leg 2 to move backward, thereby opening the legs of the stepladder 1 (see Fig. 2). Also, when the stepladder 1 is in the open leg state, turning on the "close" switch S1 causes the two front movement devices 5 to move backward and the rear movement device 5 to move forward, thereby closing the legs of the stepladder 1 (see Fig. 3).

[0026] When the moving device 5 moves forward or backward, each support 4 tilts, causing the angle between the moving device 5 and the support 4 to change. However, as described above, the housing 51 of the moving device 5 is configured to be able to swing freely relative to the support 4, allowing for angle changes.

[0027] A limiter device 6 is provided at the top of the two front and rear support pillars 4 so as to span them.

[0028] The limiter device 6 includes two bars 61 and a case body 62 that connects the two bars 61 and has a hinge built in. The case body 62 houses two limit switches (not shown).

[0029] The non-connected ends of the two bars 61 are supported rotatably on the tops of the two front and rear support posts 4, respectively, and can be bent around the case body 62 when the stepladder 1 is opened or closed (see Figures 2 and 3).

[0030] When the stepladder 1 is in a closed leg state (see Figure 3), the opening / closing switch S1 is turned on to "open" to move the moving device 5, and when the stepladder 1 reaches an open leg state (see Figure 2), that is, when the two bars 61 are approximately horizontal, one of the limit switches is activated and the motor of the moving device 5 is stopped.

[0031] Furthermore, when the stepladder 1 is in the open leg state (see Figure 2), the open / close switch S1 is turned on to "close" to move the moving device 5, and when the stepladder 1 reaches the closed leg state (see Figure 3), that is, when the two bars 61 are bent and each support 4 is in an almost vertical position, the other limit switch is activated and the motor of the moving device 5 is stopped.

[0032] In this way, the leg opening and closing operations of the stepladder 1 are both performed automatically by simply operating the open / close switch S1, and are automatically stopped when a predetermined angle is reached.

[0033] Further, at the lower end of each support column 4, an extension mechanism 7 is provided so that the movement device 5 can be extended and retracted in the direction in which the support column 4 extends.

[0034] By adjusting the four extension mechanisms 7, the length of each support 4 (more precisely, the distance between the bottom end of the support 4 and the moving device 5) can be increased or decreased, thereby ensuring that the stepladder 1 is kept horizontal.

[0035] The telescopic mechanism 7 consists of a motor M provided inside the housing 51 of the moving device 5, a feed screw 71 connected to the motor M and provided so as to penetrate deep into the support 4, and a nut 72 that is threaded with the feed screw 71 and fixed to the lower end of the support 4.

[0036] A feed screw cover 4b is provided at the bottom of the support column 4 so as to surround the feed screw 71 (see FIGS. 6 and 7).

[0037] This telescoping mechanism 7 is activated by operating the horizontal switch S2. When the horizontal switch S2 is turned "ON," the feed screw 71 rotates. Since the feed screw 71 is threaded into a fixing nut 72 on the support 4 side, the distance between the lower end of the support 4 and the moving device 5 increases or decreases. As a result, the amount by which the moving device 5 protrudes from the support 4 increases or decreases, and the length of the support 4 is adjusted (see Figures 6 and 7).

[0038] A level 73 is provided on the top board 41U, and this level 73 also serves as a level sensor. When the level switch S2 is turned "ON," the inclination (degree of level) of the stepladder 1 detected by the level 73 determines whether or not the length of any of the support pillars 4 needs to be adjusted, and based on this, a specified extension mechanism 7 is driven to automatically maintain the level of the stepladder 1.

[0039] An anti-slip mechanism 8 is provided at the bottom of the housing 51 of the moving device 5.

[0040] The anti-slip mechanism 8 comprises an anti-slip member 81 provided on the underside of the housing 51 so as to be movable in the vertical direction, and a hydraulic device 82 that can move the anti-slip member 81 in the vertical direction. In the drawings, only the pump P of the hydraulic device 82 is shown (see FIGS. 6 and 7).

[0041] The anti-slip material 81 is made of a material, such as rubber, that is not slippery on the installation surface G, and is protruded downward from the housing 51 by a hydraulic device 82 that operates in conjunction with the stopping of the moving devices 5, and is pressed against the installation surface G (see FIG. 7). As a result, when the stepladder 1 is in the open leg state and the crawlers 51 of each moving device 5 are stopped, the crawlers 51 will not slip, even if the installation surface G is sloped or uneven, and the stepladder 1 can be used in a stable state.

[0042] As described above, according to the present invention, the crawler can be driven simply by operating the open / close switch S1, and the limiter device 6 can detect that the legs are in the open position, thereby automatically stopping the leg-opening operation. This eliminates the need for the worker to open and close the legs of the stepladder, thereby reducing the workload.

[0043] This is particularly effective for large stepladders, or when the legs of the stepladder must be opened and closed repeatedly, such as when performing wiring work.

[0044] Moreover, since the moving device 5 is provided at the lower end of the support 4 of the stepladder 1 and the moving device 5 uses a crawler 52, the moving device 5 can move even if the installation surface G is uneven or not slippery, and can be used regardless of the condition of the installation surface G.

[0045] Furthermore, in the stepladder 1 of this embodiment, each support 4 is equipped with an extension mechanism 6, and a spirit level (horizontal sensor) 73 is provided, which senses the inclination state (degree of horizontality) of the stepladder 1 and automatically ensures a horizontal state, allowing work to be done safely on the stepladder 1.

[0046] The above describes the embodiments of the present invention, but the specific configuration is not limited to the above-mentioned embodiments, and even if there are design changes within the scope of the present invention that do not deviate from the gist of the present invention, they are included in the present invention.

[0047] For example, in the above embodiment, one horizontal switch S2 is used to automatically ensure that the stepladder 1 is level, but the present invention is not limited to this. A separate switch may be provided for each extension mechanism 7, and the length of each support 4 may be manually adjusted to ensure that the stepladder is level. [Explanation of symbols]

[0048] 1 stepladder 2 legs 3 Hinge 4 pillars 41 Step 5. Mobile Devices S1 Open / close switch (switch) 52 Crawler 6 Limiter device 7 Telescopic mechanism 73 Level (Level Sensor)

Claims

1. A stepladder is a ladder-like leg section with several steps provided between two posts, and the two legs are arranged facing each other in the front and rear and connected at the top via a hinge, a moving device having crawlers at the lower ends of the support columns that can move in the forward and backward directions; a limiter device that stops the movement device when the front and rear legs are in an open leg state or a closed leg state, the moving device has a drive means for driving the crawler and a switch for activating the drive means, a limiter device that stops the drive means of the moving device when the front and rear legs are in the open leg state or the closed leg state, By operating the switch, the front and rear moving devices are moved in directions away from each other, causing the legs to open, and by operating the switch, the front and rear moving devices are moved in directions approaching each other, causing the legs to close. A stepladder characterized by:

2. an extension mechanism provided on each of the support columns for individually extending or shortening the length of each support column; a horizontal sensor provided on the leg portion for detecting the horizontality of the step; The length of the predetermined support pole is adjusted based on the detection result of the horizontal sensor to ensure a horizontal state.

2. The stepladder according to claim 1 .

Images