Stepladder

Abstract

To provide a stepladder that enables a user to work safely while maintaining a stable posture at the top of the stepladder.SOLUTION: A stepladder 1 includes a stepladder main body 2, a first arm 3 provided on the stepladder main body 2 so as to be freely rotatable in the vertical direction, and first fixing means for fixing the first arm 3 when rotated upward, the first arm 3 extending horizontally and having a horizontal shaft portion 22 held at the top of the stepladder main body 2 so as to be freely rotatable and slidable in the horizontal direction, and a vertical shaft portion 23 extending vertically from the end of the horizontal shaft portion 22; the first fixing means including a hook 31 provided on the horizontal shaft portion side end in the longitudinal direction of the vertical shaft portion of the first arm, and protrusions 32a to 32c provided on the side of the stepladder main body 2 and capable of engaging the hook 31 when the first arm 3 is rotated upward.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a stepladder. [Background technology]

[0002] BACKGROUND ART Stepladders have been proposed in the past in which pipes housed within the supports of the ladder section can be pulled out upward and used as handrails (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2001-329773 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in conventional stepladders such as those described above, the pipes are pulled out in an extension of the support poles, which poses the problem that the pipes get in the way when, for example, the user works while sitting astride the top of the stepladder.

[0005] Therefore, the present invention has been made in consideration of the above problems, and has as its object to provide a stepladder that allows a user to work safely while maintaining a stable posture at the top of the stepladder. [Means for solving the problem]

[0006] In order to solve the above problems, the present invention provides: The stepladder itself, A first arm provided on the stepladder body so as to be rotatable in the vertical direction; a first fixing means for fixing the first arm rotated upward, The first arm has a horizontal shaft portion extending horizontally and held rotatably and slidably in the horizontal direction at the upper part of the stepladder body, and a vertical shaft portion extending vertically from an end of the horizontal shaft portion, The present invention provides a stepladder characterized in that the first fixing means comprises a hook provided at the end of the horizontal shaft portion in the longitudinal direction of the vertical shaft portion of the first arm, and a protrusion provided on the side of the stepladder main body that can engage the hook when the first arm is rotated upward. [Effects of the Invention]

[0007] According to the present invention, a stepladder can be provided that allows a user to work safely while maintaining a stable posture at the top of the stepladder. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is an oblique view showing the stepladder state of the first embodiment of the present invention, where (a) shows the state in which the first and second auxiliary arms are not in use, and (b) shows the state in which the first and second auxiliary arms are in use. [Figure 2] FIG. 2 is a side view showing the stepladder according to the first embodiment in the stepladder state, where (a) shows the state seen from the first auxiliary arm side, and (b) shows the state seen from the second auxiliary arm side. [Figure 3] Figure 3 is a side view showing the stepladder state of the stepladder of the first embodiment, where (a) shows the first and second auxiliary arms not in use, and (b) shows the first and second auxiliary arms in use. [Figure 4] Figure 4 is a side view of the stepladder of the first embodiment, where (a) is an enlarged view showing the configuration of the fixing means of the first auxiliary arm, (b) is a view showing the stepladder in the ladder state, and (c) is a view showing the hook portion and protrusion portion of the fixing means of the first auxiliary arm engaged with each other. [Figure 5] FIG. 5 is a side view showing the stepladder according to the second embodiment in the stepladder state, where (a) shows the state seen from the first auxiliary arm side, and (b) shows the state seen from the second auxiliary arm side. [Figure 6] Figure 6 is a partially enlarged oblique view showing the stepladder state of the stepladder of the second embodiment, where (a) shows the configuration of the first auxiliary arm, (b) shows the configuration of the second auxiliary arm, and (c) shows the configuration of one end of the horizontal axis portion of the first auxiliary arm and the reinforcement portion. [Figure 7] Figure 7 is a side view showing the stepladder state of the stepladder of the second embodiment, where (a) shows the first and second auxiliary arms not in use, and (b) shows the first and second auxiliary arms in use. DETAILED DESCRIPTION OF THE INVENTION

[0009] Stepladders according to embodiments of the present invention will be described with reference to the accompanying drawings. (First embodiment) The stepladder 1 according to the first embodiment of the present invention shown in Figure 1(a) comprises a stepladder main body 2 and first and second auxiliary arms 3 and 4 for assisting a user who climbs onto the stepladder main body 2 to perform work.

[0010] The stepladder body 2 has the same basic configuration as a general stepladder, and has a pair of ladder sections 5a, 5b and a pair of hinge sections 6a, 6b that connect the ladder sections 5a, 5b so that they can be opened and closed freely.

[0011] The ladder section 5a is composed of two rectangular pillar-shaped supports 7a, 7b arranged in a V-shape, a plurality of rectangular pillar-shaped rungs 8, 8 (two in this embodiment) connecting the supports 7a, 7b, and a rectangular top plate 9 connecting the upper ends of the supports 7a, 7b. The configuration of the ladder section 5b is the same as that of the ladder section 5a.

[0012] The hinge section 6b is roughly feather-shaped and comprises a pair of plate-like members 11a, 11b and a rotary shaft 12 that rotatably connects the plate-like members 11a, 11b. The plate-like member 11a is fixed to the side of the upper end of the support 7a of the ladder section 5b, and the plate-like member 11b is fixed to the side of the upper end of the support 7b of the ladder section 5a. The configuration of the hinge section 6a is the same as that of the hinge section 6b. The hinge sections 6a, 6b allow the ladder sections 5a, 5b to be opened and closed freely.

[0013] The stepladder main body 2 can be placed in a stepladder state in which the ladder sections 5a and 5b are opened in a V-shape and can be used as a stepladder; in a ladder state in which the ladder sections 5a and 5b are opened 180 degrees and can be used as a ladder as shown in Figure 4(b); or in an unused state in which the ladder sections 5a and 5b are closed and can be easily carried and stored.

[0014] In addition, on both sides of the ladder sections 5a, 5b, there are provided a pair of first locking mechanisms 13a, 13b for fixing the ladder sections 5a, 5b in the stepladder state, and a pair of second locking mechanisms 14a, 14b for fixing the ladder sections 5a, 5b in the ladder state (see Figures 3(a) and 4(b)).

[0015] As shown in Figure 3(a), the first locking mechanism 13b consists of an axle 15 provided on the side of support 7b of ladder section 5a at a longitudinally intermediate position of support 7b, an axle 16 provided on the side of support 7a of ladder section 5b at a longitudinally intermediate position of support 7a, and an elongated, rounded, rectangular plate-like member 17 having one end rotatably attached to axle 16 and the other end having a groove 18 into which axle 15 can be fitted. When opening the ladder sections 5a and 5b, the user can rotate plate-like member 17 and fit axle 15 into groove 18 of plate-like member 17 to lock the ladder sections 5a and 5b in a stepladder state. The configuration of first locking mechanism 13a is the same as that of first locking mechanism 13b.

[0016] As shown in Fig. 3(a), the second locking mechanism 14b has the same configuration as the first locking mechanism 13b, and is composed of an axle 15 provided on the plate-shaped member 11b of the hinge portion 6b, an axle 16 provided on the plate-shaped member 11a of the hinge portion 6b, and a plate-shaped member 17 rotatably attached to the axle 16. As shown in Fig. 4(b), the user can use the second locking mechanism 14b to lock the ladder portions 5a, 5b in the ladder state. The configuration of the second locking mechanism 14a (not shown) is the same as that of the second locking mechanism 14b.

[0017] As shown in FIG. 2(a), the first auxiliary arm 3 is a thin, elongated rod-like member having a generally L-shape overall, and comprises a cylindrical horizontal shaft portion 22 extending horizontally, a cylindrical vertical shaft portion 23 extending vertically from one end of the horizontal shaft portion 22, and a handle portion 24 extending horizontally inward from the tip of the vertical shaft portion 23. The handle portion 24 comprises, in order from the vertical shaft portion 23 side, a cylindrical shaft portion 25 and a bale-shaped grip portion 26, and is shorter overall than the horizontal shaft portion 22. Note that the shape of the grip portion 26 is not limited to the bale shape and may be other shapes, such as a cylindrical shape. Furthermore, the shape of the vertical shaft portion 23 is not limited to the cylindrical shape and may be other shapes, such as a rectangular pillar shape.

[0018] Circular through-holes (not shown) are formed in the upper portions of the supports 7a and 7b of the ladder section 5a of the stepladder main body 2, more specifically, just below the top plate 9, so as to pass horizontally through the supports 7a and 7b. Also, circular through-holes (not shown) are formed in the plate-like members 11a and 11b of the hinge sections 6a and 6b, respectively, so as to face the through-holes in the supports 7a and 7b of the ladder section 5a. The horizontal shaft 22 of the first auxiliary arm 3 is inserted into these through-holes so as to be slidable horizontally and rotatable.

[0019] In addition, to prevent the horizontal shaft portion 22 from falling out of the through holes of the posts 7a and 7b of the ladder portion 5a, the through hole of the plate-shaped member 11a of the hinge portion 6a, and the through hole of the plate-shaped member 11b of the hinge portion 6b, a screw groove (not shown) is formed on the end of the horizontal shaft portion 22 opposite the vertical shaft portion 23, and a nut 29 is attached so that it can be removed (see Figure 2(a)).

[0020] With the above configuration, the first auxiliary arm 3 is slidable in the horizontal direction relative to the stepladder main body 2 and is rotatable in the vertical direction. Additionally, by removing the nut 29 from the horizontal shaft portion 22, the first auxiliary arm 3 can be removed from the stepladder main body 2. This allows the user to use the stepladder 1 by removing the first auxiliary arm 3 from the stepladder main body 2 depending on the type of work, or to replace the first auxiliary arm 3 with a new one if it is damaged, etc.

[0021] As shown in Fig. 4(a), a hook portion 31 having a generally rectangular pillar shape extending outward in the longitudinal direction is integrally provided on the end portion of the vertical shaft portion 23 of the first auxiliary arm 3 on the side of the horizontal shaft portion 22 in the longitudinal direction. The hook portion 31 is formed with a semicircular groove 31a that can be engaged with protrusions 32a to 32c of the hinge portion 6b, which will be described later.

[0022] As shown in FIGS. 3(a) and 4(a), the plate-shaped member 11b of the hinge portion 6b of the stepladder main body 2 is provided with three protrusions 32a to 32c aligned in the circumferential direction around the horizontal shaft portion 22, at a position closer to the rotation axis 12 than the horizontal shaft portion 22 of the first auxiliary arm 3. As shown in FIG. 4(c), each of the protrusions 32a to 32c consists of a disk-shaped head portion 33 and a cylindrical shaft portion 34 with a smaller diameter than the head portion 33. Note that the protrusions 32a to 32c may be, for example, rivet-type metal fittings attached to the plate-shaped member 11b. The protrusions 32a to 32c of the hinge portion 6b and the hook portion 31 of the first auxiliary arm 3 form a fixing means for fixing the position of the first auxiliary arm 3 when the first auxiliary arm 3 is rotated upward relative to the stepladder main body 2 in the stepladder state.

[0023] A user of the stepladder 1 configured as described above can climb onto the stepladder body 2 with the ladder sections 5a, 5b open and positioned in the stepladder state, and sit astride the top panels 9. The user then slides the first auxiliary arm 3 horizontally outward (to the right in FIG. 1(a)), rotates it upward, and slides it horizontally inward (to the left in FIG. 1(a)) to engage the hook section 31 of the first auxiliary arm 3 with one of the protrusions 32a-32c of the hinge section 6b. This allows the user to raise the first auxiliary arm 3 (to be used). Specifically, when the hook section 31 engages with the protrusions 32a-32c, the load of the vertical shaft section 23 and the handle section 24 is applied from the hook section 31 to the protrusions 32a-32c by the principle of leverage with the center of rotation of the horizontal shaft section 22 as the fulcrum. This allows the hook section 31 to remain engaged with the protrusions 32a-32c, i.e., the first auxiliary arm 3 to be maintained in use. The user can change the raised position of the first auxiliary arm 3, i.e., the height of the handle portion 24, by changing the protrusions 32a to 32c of the hinge portion 6b that engage the hook portion 31 of the first auxiliary arm 3 (see FIG. 3(b)). Also, the user can lower the first auxiliary arm 3 and return it to its unused state by reversing the above-described procedure.

[0024] 4(a), a small plate-like stopper portion 35 extending horizontally outward (toward the viewer in the direction perpendicular to the plane of the drawing in FIG. 4(a)) is integrally provided on the plate-like member 11b of the hinge portion 6b at a position on the upper end side of the support post 7b. With this configuration, when the first auxiliary arm 3 is rotated upward relative to the stepladder main body 2, the vertical shaft portion 23 abuts against the stopper portion 35, thereby preventing the first auxiliary arm 3 from rotating excessively and rising too high.

[0025] When the first auxiliary arm 3 is in use, the hook portion 31 is restricted from moving horizontally by the heads 33 of the protrusions 32a to 32c (see FIG. 4(c)). This configuration prevents the first auxiliary arm 3 from sliding outward in the horizontal direction and disengaging the hook portion 31 from the protrusions 32a to 32c unintentionally by the user, thereby preventing the first auxiliary arm 3 from rotating and descending.

[0026] A horizontally extending groove 36 is formed on the front surface of the support 7b of the ladder section 5a (the surface on the near side in Figure 1(b)). With this configuration, when the first auxiliary arm 3 is rotated downward relative to the stepladder main body 2, i.e., when the first auxiliary arm 3 is not in use, the shaft 25 of the handle section 24 can be stored in the groove 36. As a result, the first auxiliary arm 3 does not protrude from the front side of the ladder section 5a, and therefore the first auxiliary arm 3 does not get in the way when the user climbs up or down the stepladder main body 2 (see Figure 1(a)).

[0027] As shown in Figure 1(a), the length of the vertical shaft 23 of the first auxiliary arm 3 is designed so that when the first auxiliary arm 3 is not in use, the handle 24 is located immediately below the uppermost rung 8 of the ladder section 5a of the stepladder main body 2. Also, as described above, the horizontal shaft 22 of the first auxiliary arm 3 is located immediately below the top plate 9 of the ladder section 5a of the stepladder main body 2. With this configuration, the handle 24 and horizontal shaft 22 of the first auxiliary arm 3 do not get in the way when the user climbs up or down the stepladder main body 2.

[0028] The second auxiliary arm 4 has a similar basic configuration to the first auxiliary arm 3, so the same parts are given the same reference numerals and their explanations are omitted, and only the different parts will be explained. As shown in Figure 2(b), the second auxiliary arm 4 is an elongated rod-like member having an overall rectangular shape, and is composed of a horizontal shaft portion 22, two vertical shaft portions 23, 23 extending parallel to each other in the vertical direction from both ends of the horizontal shaft portion 22, and a handle portion 37 extending horizontally inward from the tip of one of the vertical shaft portions 23 to reach the tip of the other vertical shaft portion 23.

[0029] The handle portion 37 is made up of, in order from the side of the one vertical shaft portion 23 mentioned above, a cylindrical shaft portion 38, a cylindrical grip portion 39 that is thinner than the shaft portion 38, and a cylindrical shaft portion 40 that has the same diameter as the shaft portion 38. The grip portion 39 is not limited to a cylindrical shape and may have other shapes, such as a rice bag shape or a square pillar shape. The other vertical shaft portion 23 described above is integrally provided with a hook portion 31, similar to the vertical shaft portion 23 of the first auxiliary arm 3.

[0030] Similar to the supports 7a, 7b of the ladder section 5b, through holes (not shown) are formed in the upper portions of the supports 7a, 7b of the ladder section 5b of the stepladder main body 2. Also, through holes (not shown) are formed in the plate-shaped member 11b of the hinge section 6a and the plate-shaped member 11a of the hinge section 6b so as to face the through holes in the supports 7a, 7b of the ladder section 5b. The horizontal shaft portion 22 of the second auxiliary arm 4 is inserted into these through holes so as to be slidable horizontally and rotatable vertically. This configuration allows the second auxiliary arm 4 to slide horizontally and rotate vertically relative to the stepladder main body 2.

[0031] Similar to the plate-like member 11b of the hinge portion 6b, the plate-like member 11b of the hinge portion 6b is provided with three protrusions 32a to 32c and a stopper portion 35 (all not shown). As shown in Fig. 2(b), grooves 36, 36 are provided on the front surfaces of the supports 7a, 7b of the ladder portion 5b, similar to the supports 7b of the ladder portion 5a.

[0032] Here, a circular ring portion (not shown) is integrally provided at the longitudinal end of the other vertical shaft portion 23 (left side in FIG. 2(b)) of the second auxiliary arm 4, which is closer to the horizontal shaft portion 22. Also, a thread groove (not shown) is formed at the end of the horizontal shaft portion 22 closer to the other vertical shaft portion 23. The circular ring portion of the vertical shaft portion 23 is fitted onto the end of the horizontal shaft portion 22 with the thread groove, and a nut 29 is removably attached. With this configuration, the second auxiliary arm 4 can be removed from the stepladder main body 2 by removing the nut 29 from the horizontal shaft portion 22.

[0033] With the above configuration, the user can set the stepladder main body 2 to the stepladder state and put the second auxiliary arm 4 into a usable state by following the same procedure as for the first auxiliary arm 3. The second auxiliary arm 4 can achieve the same effects as the first auxiliary arm 3 described above.

[0034] With the stepladder 1 according to this embodiment, when a user climbs onto the stepladder main body 2 in the stepladder state and sits astride the top panels 9, 9 to perform work, the user can grasp the handles 24, 37 and the vertical shafts 23 of the first and second auxiliary arms 3, 4 to adjust their position by setting the first and second auxiliary arms 3, 4 to a desired height, for example, a height in which the handles 24, 37 are positioned near the user's knees (400 to 500 mm above the top panels 9, 9). Furthermore, the user can hang tools, equipment, materials, safety harnesses, etc. from the handles 24, 37 of the first and second auxiliary arms 3, 4, leaving both hands free to prepare for work or adjust their position. The user can then work in a stable position while grasping the handles 24, 37 and the vertical shafts 23 of the first and second auxiliary arms 3, 4, ensuring safety.

[0035] Furthermore, when the user needs to perform work while standing on the top boards 9, 9 of the stepladder main body 2 in the stepladder state, the user can grasp the first auxiliary arm 3 or the second auxiliary arm 4 in the usable state, thereby climbing up and down the top boards 9, 9 more safely while maintaining a balanced body position.

[0036] When the user climbs up and down the stepladder main body 2 in the ladder state or when climbing up and down the stepladder main body 2 in the stepladder state, the first and second auxiliary arms 3, 4 are not in the way by putting them into an unused state.

[0037] As mentioned above, the handle portion 24 of the first auxiliary arm 3 is designed to be shorter than the horizontal axis portion 22, so the user can climb up and down the ladder main body 2 in ladder form while leaving the first auxiliary arm 3 in use. As described above, the support post 7b of the ladder section 5a and the support posts 7a, 7b of the ladder section 5b each have the groove 36, but they may be configured not to have this. In this case, when the user climbs up or down the stepladder main body 2 in the stepladder state or ladder state with the first and second auxiliary arms 3, 4 not in use, the handles 24, 37 of the first and second auxiliary arms 3, 4 will protrude slightly from the front side of the ladder sections 5a, 5b, respectively, but the handles 24, 37 are located immediately below the rungs 8, 8 and therefore do not get in the way.

[0038] (Second embodiment) Regarding the stepladder 41 according to the second embodiment of the present invention shown in Figures 5(a) and 5(b), the same components as those in the first embodiment are given the same symbols and their explanations are omitted, and only the different components will be explained.

[0039] The first auxiliary arm 42 of the stepladder 41 according to this embodiment comprises a cylindrical horizontal shaft 43 extending horizontally, a vertical shaft 44 that is separate from the horizontal shaft 43 and extends vertically from one end of the horizontal shaft 43, and a handle 45 that extends horizontally inward from the tip of the vertical shaft 44. The handle 45 comprises only the bale-shaped grip 26.

[0040] As shown in Figure 6(a), the horizontal shaft portion 43 has thread grooves at both ends, and a hook portion 46 is integrally formed on the opposite side of the vertical shaft portion 44 in the longitudinal direction. The hook portion 46 has a configuration similar to the hook portion 31 of the vertical shaft portion 23 of the first auxiliary arm 3 in the first embodiment. Furthermore, L-shaped portions 47, 47 are integrally formed at positions that divide the horizontal shaft portion 43 into thirds in the longitudinal direction. The L-shaped portions 47, 47 are made of L-shaped plate members with through-holes 47a at their tips.

[0041] A first extension step 48 is attached to the horizontal shaft portion 43 to extend the area of ​​the top plate 9 of the ladder portion 5a when the stepladder main body 2 is in the stepladder state. As shown in Figure 6(a), the first expansion step 48 is made up of a rectangular plate-shaped portion 49 and two protrusions 50, 50 that are integrally formed on the back surface of the plate-shaped portion 49. The protrusions 50 are rectangular plate-shaped with through holes 50a at their tips, and are fixed to the L-shaped portion 47 of the first auxiliary arm 42 by fitting nuts 52 onto bolts 51 inserted into the respective through holes 47a, 50a. When fitting the nuts 52 onto the bolts 51, two washers 53, 53 are arranged to sandwich the protrusions 50 and the L-shaped portion 47 therebetween.

[0042] Specifically, the attachment angle of the first extension step 48 relative to the first auxiliary arm 42, i.e., the angle formed by the L-shaped portions 47, 47 and the protrusions 50, 50, is set so that the first extension step 48 is stored in the space below the top plate 9 of the ladder section 5a when the first auxiliary arm 42 is not in use, and is located directly beside the top plate 9 of the ladder section 5a when the first auxiliary arm 42 is in use. More specifically, when the user engages the hook portion 31 of the vertical shaft portion 44 with the lowest protrusion 32a of the hinge portion 6b when the first auxiliary arm 42 is in use, the top plate 9 of the ladder section 5a and the plate-like portion 49 of the first extension step 48 are positioned on the same plane (see Figure 7(b)).

[0043] The user can adjust the attachment angle of the first extension step 48 relative to the first auxiliary arm 42 by loosening the bolt 51 and nut 52. The user can also remove the first extension step 48 from the first auxiliary arm 42 and use the stepladder 41 depending on the work they are doing by removing the nut 52 from the bolt 51.

[0044] As shown in FIG. 6( a), the vertical shaft 44 is made of a thin, elongated rectangular plate-like member, and a circular through-hole 44a is formed at the longitudinal end of the vertical shaft 44 on the horizontal shaft 43 side, facing the aforementioned through-hole (not shown) in the support 7b of the ladder section 5a. The longitudinal end of the vertical shaft 44 on the handle section 45 side is integrally provided with a bent section 65 that is bent horizontally inward in a U-shape, and the handle section 45 is provided near the tip of the bent section 65. With this configuration, when the first auxiliary arm 42 is not in use, the bent section 65 wraps around the horizontal inside of the support 7b of the ladder section 5a, allowing the handle section 45 to be stored directly below the tread 8. Therefore, the handle section 45 of the first auxiliary arm 42 does not get in the way when the user climbs up and down the stepladder body 2.

[0045] A reinforcing portion 54, which is made by bending a rectangular thin plate member into a U-shape, is attached to the upper portion of the support pillar 7a of the ladder portion 5a so as to cover the horizontal inner side surface of the support pillar 7a. A circular through-hole 54a is formed in the reinforcing portion 54 so as to face the above-mentioned through-hole (not shown) of the support pillar 7a. Furthermore, as shown in FIG. 6(c), the reinforcing portion 54 is provided with protrusions 55a to 55c similar to those of the plate-like member 11b of the hinge portion 6b.

[0046] One end of the horizontal shaft 43 is inserted into through-holes (not shown) in the support 7b of the ladder section 5a and the plate-like member 11b of the hinge section 6b, through-hole 44a of the vertical shaft 44, and washer 57, and a nut 58 is removably attached. The other end of the horizontal shaft 43 is inserted into through-hole 54a of the reinforcing section 54, through-holes (not shown) in the support 7a of the ladder section 5a and the plate-like member 11a of the hinge section 6a, washer 59, spring 60, and washer 61, and a nut 62 is removably attached. With this configuration, the vertical shaft 44 is fixed to the horizontal shaft 43 and integrated with it, and the first auxiliary arm 42 is slidable horizontally and rotatable up and down relative to the stepladder body 2. The first auxiliary arm 42 is biased by a spring 60 toward the vertical shaft 44 in the longitudinal direction of the horizontal shaft 43.

[0047] When the user places the first auxiliary arm 42 in a usable state, the hook portion 31 of the vertical shaft portion 44 engages with one of the protrusions 32a to 32c of the hinge portion 6b, thereby causing the hook portion 46 of the horizontal shaft portion 43 to engage with the corresponding protrusions 55a to 55c of the reinforcing portion 54. This makes it possible to more securely maintain the usable state of the first auxiliary arm 42. Note that the support 7a of the ladder portion 5a may not be provided with the reinforcing portion 54, and the protrusions 55a to 55c may be provided directly on the horizontally inner side surface of the support 7a.

[0048] The first auxiliary arm 42 configured as described above can achieve the same effect as the first auxiliary arm 3 in the first embodiment. Furthermore, when the stepladder main body 2 is in the stepladder state and the first auxiliary arm 42 is in the use state, the first extension step 48 also rotates together with the horizontal shaft portion 43 and rises to the side of the top plate 9 of the ladder portion 5a, thereby expanding the area of ​​the top plate 9. This allows the user to work while sitting in a more stable position on the top plates 9, 9. Furthermore, even if the user needs to stand on the top plates 9, 9 to work, the user can work more safely while maintaining a balanced posture.

[0049] The second auxiliary arm 63 has a basic configuration similar to that of the first auxiliary arm 42, and the same parts are denoted by the same reference numerals and explanations thereof will be omitted, and only the different parts will be explained. As shown in Figures 5(b) and 6(b), the second auxiliary arm 63 is a rectangular frame-shaped member overall, and comprises a horizontal shaft 43, two vertical shafts 44, 44 extending parallel to each other in the vertical direction from both ends of the horizontal shaft 43, and a handle 45 extending horizontally inward from a bent portion 65 of one of the vertical shafts 44 to reach the bent portion 65 of the other vertical shaft 44. The handle 45 comprises only a grip portion 39 having an elongated cylindrical shape. The hook portion 31 is provided only on one of the vertical shafts 44 (the one on the right in Figures 5(b) and 6(b)). A second extension step 64 similar to the first extension step 48 is attached to the horizontal shaft portion 43 of the second auxiliary arm 63. A reinforcing portion 54 is attached to the upper portion of the support 7a of the ladder portion 5b.

[0050] Like the first auxiliary arm 42, the second auxiliary arm 63 can be switched between an in-use state and an in-use state, and can achieve the same effects as the first auxiliary arm 42 and the second auxiliary arm 4 in the first embodiment. In particular, when the stepladder main body 2 is in the stepladder state and both the first auxiliary arm 42 and the second auxiliary arm 63 are in the in-use state, the first and second extension steps 48, 64 can expand the area of ​​the top boards 9, 9 to the maximum, specifically 1.5 to 2 times. Therefore, the user can perform work both while sitting on the top boards 9, 9 and while standing on the top boards 9, 9, more stably and safely.

[0051] It is more preferable that the stepladder 41 according to this embodiment has a locking mechanism for fixing the first and second extension steps 48, 64 when the first and second auxiliary arms 42, 63 are in the use state in the stepladder main body 2 in the stepladder state. For example, a locking mechanism similar to the second locking mechanism 14a described above may be provided on the upper surface of the top plate 9 of the ladder section 5a and the surface of the plate-shaped portion 49 of the first extension step 48, and on the upper surface of the top plate 9 of the ladder section 5b and the surface of the plate-shaped portion 49 of the second extension step 64, respectively. This allows the first and second extension steps 48, 64 to more stably support the weight of the user even when applied thereto.

[0052] According to each of the above embodiments, it is possible to realize a user-friendly stepladder 1, 41 that has a simple configuration, is low cost, and allows the user to work safely while maintaining a stable posture at the top of the stepladder. In addition, from the viewpoint of strength, it is preferable that all of the components constituting the stepladders 1 and 41 according to each embodiment are made of metal, and in particular, aluminum, which is lightweight, strong, and rust-resistant.

[0053] The stepladder 1, 41 according to each embodiment includes both the first auxiliary arm 3, 42 and the second auxiliary arm 4, 63, but this is not limited thereto and the stepladder 1, 41 may be configured to include only one of them. The stepladder 1, 41 may also be configured to include the first auxiliary arm 3, 42 instead of the second auxiliary arm 4, 63, i.e., to include two first auxiliary arms 3, 42, or may be configured to include the second auxiliary arm 4, 63 instead of the first auxiliary arm 3, 42, i.e., to include two second auxiliary arms 4, 63.

[0054] Although each embodiment shows a 3-foot stepladder 1, 41 as an example, the present invention is not limited to this and may be applied to a stepladder of 3 feet or more. For example, if the present invention is applied to a 7-foot or 8-foot stepladder for working at height, the effect of the present invention will be maximized. In each embodiment, the hinge portions 6a, 6b and the reinforcing portion 54 are configured to have three protrusions 32a to 32c and three protrusions 55a to 55c, respectively, as described above, but the number of protrusions is not limited to this and may be one, two, or four or more.

[0055] The configurations of the stepladders 1, 41 according to the respective embodiments may be interchanged or combined with each other. For example, the first and second extension steps 48, 64 and the hook portions 46 and reinforcing portions 54 of the first and second auxiliary arms 42, 63 in the second embodiment may be applied to the stepladder 1 according to the first embodiment. Also, for example, the vertical shaft portions 44 of the first and second auxiliary arms 42, 63 in the second embodiment may be replaced with the vertical shaft portions 23 of the first and second auxiliary arms 3, 4 in the first embodiment.

[0056] For example, the first and second auxiliary arms 3 and 4 of the first embodiment may be configured such that the vertical shafts 23 are shorter than the horizontal shafts 22, the handles 24 and 37 are omitted, and the first and second extension steps 48 and 64 of the second embodiment are further included. This allows the first and second auxiliary arms to be used as levers to raise and lower the first and second extension steps 48 and 64 without being used to assist the user's work. First and second auxiliary arms configured in this manner are particularly useful when applied to, for example, a 3-foot or 4-foot stepladder for work at relatively low heights. In the stepladder 1 according to the first embodiment, the first and second auxiliary arms configured in this manner and the first and second auxiliary arms 3 and 4 described above may be detached and replaced depending on the type of work being performed. [Explanation of symbols]

[0057] 1, 41 Stepladder 2 Stepladder body 3, 42 First auxiliary arm 4, 63 Second auxiliary arm 5a, 5b ladder section 6a, 6b Hinge part 7a, 7b struts 8 Stepping Rail 11a, 11b plate-shaped members 12 Rotation axis 13a, 13b First locking mechanism 14a, 14b Second locking mechanism 22, 43 Horizontal shaft 23, 44 Vertical shaft 24, 37, 45 Handle 31, 46 Hook part 32a~32c protrusion 48 First Expansion Step 54 Reinforcement 64 Second Expansion Step 65 Bend

Claims

1. The stepladder body, A first arm provided on the stepladder body so as to be rotatable in the vertical direction; a first fixing means for fixing the first arm that has been rotated upward, The first arm has a horizontal shaft portion extending horizontally and held rotatably and slidably in the horizontal direction at the upper portion of the stepladder body, and a vertical shaft portion extending vertically from an end of the horizontal shaft portion, A stepladder characterized in that the first fixing means comprises a hook provided at the end of the horizontal shaft portion in the longitudinal direction of the vertical shaft portion of the first arm, and a protrusion provided on the side of the stepladder main body that can engage the hook when the first arm is rotated upward.

2. The stepladder described in claim 1, characterized in that the first arm consists of the horizontal shaft portion, the vertical shaft portion, and a handle portion attached to the tip of the vertical shaft portion, extending horizontally, and shorter than the horizontal shaft portion.

3. the first fixing means has a plurality of the protrusions, 2. The stepladder according to claim 1, wherein the height of the first arm is changeable by changing the protrusion that engages the hook.

4. the horizontal shaft portion of the first arm is provided with a first step that rotates together with the first arm, The stepladder described in claim 1, characterized in that when the first arm is rotated upward, the first step is positioned to the side of the top plate of the stepladder body to expand the area of ​​the top plate, and when the first arm is rotated downward, it is stored below the top plate.

5. 3. The stepladder according to claim 2, wherein the stepladder body is formed with a groove for accommodating the handle portion when the first arm is rotated downward.

6. The stepladder described in claim 2, characterized in that the vertical axis portion of the first arm is plate-shaped and has a bent portion at the end of the handle portion side in the longitudinal direction that is bent horizontally inward in a U-shape to follow the stepladder body, and the handle portion is provided at the bent portion.

7. a hook is provided on the horizontal shaft portion of the first arm on the opposite side to the vertical shaft portion in the longitudinal direction; The stepladder body has a reinforcing part that covers a part of the stepladder body, The stepladder according to claim 1, wherein the reinforcing portion is provided with a protrusion that can engage the hook of the horizontal shaft portion when the first arm is rotated upward.

8. the first arm includes the horizontal shaft portion and the vertical shaft portion, the horizontal shaft portion of the first arm is provided with a first step that rotates together with the first arm, The stepladder described in claim 1, characterized in that when the first arm is rotated upward, the first step is positioned to the side of the top plate of the stepladder body to expand the area of ​​the top plate, and when the first arm is rotated downward, it is stored below the top plate.

9. a second arm provided on the stepladder body opposite the first arm so as to be rotatable in the vertical direction; and second fixing means for fixing the second arm rotated upward, The second arm has a horizontal shaft portion extending horizontally and held rotatably and slidably in the horizontal direction at the upper portion of the stepladder body, and a vertical shaft portion extending vertically from an end of the horizontal shaft portion, The stepladder described in claim 1, characterized in that the second fixing means comprises a hook provided at the end of the horizontal shaft portion in the longitudinal direction of the vertical shaft portion of the second arm, and a protrusion provided on the side of the stepladder main body that can engage the hook when the second arm is rotated upward.

10. The stepladder described in claim 9, characterized in that the second arm consists of the horizontal shaft portion, the vertical shaft portion, a vertical shaft portion extending vertically from the other end of the horizontal shaft portion, and a handle portion extending horizontally connecting the tips of the two vertical shaft portions.

11. the second fixing means has a plurality of the protrusions, 10. The stepladder according to claim 9, wherein the height of the second arm can be changed by changing the protrusion that engages the hook.

12. the horizontal shaft portion of the second arm is provided with a second step that rotates together with the second arm, The stepladder described in claim 9, characterized in that when the second arm is rotated upward, the second step is positioned to the side of the top plate of the stepladder body to expand the area of ​​the top plate, and when the second arm is rotated downward, it is stored below the top plate.

13. The stepladder according to claim 10, wherein the stepladder body is formed with a groove for accommodating the handle portion when the second arm is rotated downward.

14. The two vertical shafts of the second arm are plate-shaped and have bent portions at the ends of the handle portion in the longitudinal direction that are bent inward in a U-shape in the horizontal direction so as to fit along the ladder body, The stepladder according to claim 10, wherein the handle portion of the second arm connects the bent portions of the two vertical shaft portions together.

15. The horizontal shaft portion of the second arm is provided with a hook on the other end side, The stepladder body has a reinforcing part that covers a part of the stepladder body, The stepladder according to claim 10, wherein the reinforcing portion is provided with a protrusion that can engage the hook of the horizontal shaft portion when the second arm is rotated upward.

16. the second arm includes the horizontal shaft portion and the vertical shaft portion, the horizontal shaft portion of the second arm is provided with a second step that rotates together with the second arm, The stepladder described in claim 9, characterized in that when the second arm is rotated upward, the second step is positioned to the side of the top plate of the stepladder body to expand the area of ​​the top plate, and when the second arm is rotated downward, it is stored below the top plate.

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