JP4617006B2 - stepladder - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a stepladder used for construction work sites, interior / exterior work such as ceilings and wall surfaces of buildings, electrical wiring work, and the like.
[0002]
[Prior art]
Conventionally, as is well known, for example, as shown in FIGS. 15 and 16, a step frame 2 is attached between a pair of support legs 1 at an appropriate interval to form a ladder frame 30. The handrail support 21 is extended upward from the upper end of the support leg 1, and the tread 6 is rotatably mounted between the opposing ladder frames 30, 30. For example, an aluminum alloy was used as the material of the handrail support column 21 and formed in a U-shaped section.
[0003]
The tread board 6 is composed of a tread board body 6a and a stay 6b that supports the tread board body 6a from below, and the stay 6b is pivotally attached at one end to a substantially central position below the tread board body 6a. The end is pivotally attached to the upper end of the support leg 1 or the lower end of the handrail support 21 or the boundary between the support leg 1 and the handrail support 21 with a mounting bracket.
[0004]
The tread board main body 6a can be pivoted at the end on which the stay 6b is not overlapped to the upper end of the support leg 1, the lower end of the handrail support 21, or the boundary between the support leg 1 and the handrail support 21 with a mounting bracket. Axis.
[0005]
The upper end portions of the handrail struts 21 and 21 are brought into contact with each other and are coupled to each other by a rectangular rotating metal fitting 11 so as to be freely rotatable. In the figure, 4 is an extension leg attached to the lower part of the support leg 1 so as to be freely extendable, 5 is a width stop material spanned between the opposing support legs 1, and 7 is a horizontal brace.
[0006]
In the case of such a stepladder, the maximum height reaches, for example, 3400 mm, so that the storage space is small, and the support leg 1 is attached to the upper and lower main legs 1a and 1b so that it can be easily carried. There are some which are divided so that the lower main leg 1b is rotatably coupled to the upper main leg 1a and can be folded upward.
[0007]
In this case, the connecting portion between the upper main leg 1a and the lower main leg 1b, for example, abuts the ends of both the upper and lower main legs 1a and 1b, and connects the connecting bracket 31 such as a channel shape to the upper main legs 1a and 1b. The upper and lower main legs 1a and 1b are connected to each other by connecting metal fittings 31 using pins or the like.
[0008]
When not in use, the pin is pulled out to remove the connecting bracket 31, the lower main leg 1b is rotated upward to overlap the upper main leg 1a, and the tread plate 6, the width stop material 5, and the horizontal brace 7 are folded to be compact. It can be easily moved and stored in a small space.
[0009]
[Problems to be solved by the invention]
When the support leg 1 is divided into upper and lower parts and can be folded, if the abutting parts of the upper and lower main legs 1a and 1b are not perfectly joined, a play due to a gap is generated, and shaking occurs when working on the tread 6. Difficult to work.
[0010]
Further, since the upper and lower main legs 1a and 1b are connected in a state where the end portions are in contact with each other, the connection strength is low, and the load from above is applied from the upper main leg 1a to the lower main leg 1b only through the joint end face. Because it is transmitted, the strength reliability of the entire stepladder is also low.
[0011]
The object of the present invention is to eliminate the inconvenience of the conventional example, and when connecting the support leg of the stepladder so that it can be folded up and down, a gap is not generated in the connecting portion so that there is no play. It is an object of the present invention to provide a stepladder that can prevent this, increase the connection strength, sufficiently support the load applied to the leg, and improve the strength of the entire stepladder.
[0012]
[Means for Solving the Problems]
In order to achieve the above object, according to the present invention, first, a ladder frame is formed by attaching a plurality of step bars between a pair of support legs at appropriate intervals, and a pair of the ladder frames are opposed to each other so that an upper end thereof is freely rotatable. In the stepladder that is pivotally attached and the tread is foldable between the ladder frames at the upper position of the support legs, the support legs are composed of the upper main legs and the lower main legs that are rotatably connected to the upper main legs. The upper main leg and the lower main leg are connected to each other by a superposed part formed with a locking part on the side, and the superposed part is pivotally attached to either the upper main leg or the lower main leg. The gist of the invention is that an engagement portion that is fastened and fixed from the outside by a metal fitting and that engages with a locking portion formed in the overlapped portion is formed on the fastening metal fitting.
[0013]
Secondly, the locking part and the engaging part are formed with irregularities, and thirdly, an outrigger that slides in the vertical direction and is rotatable in the substantially horizontal direction from the lower position is attached to the lower part of the lower main leg. This is the gist.
[0014]
According to the first aspect of the present invention, the upper main leg and the lower main leg are connected in the lateral direction because the connecting portion between the upper main leg and the lower main leg is provided with the overlapped portion. .
Therefore, there is no contact surface in the vertical direction, no gap is generated between the upper and lower sides, and no play is generated. Further, the upper main leg and the lower main leg are integrated by the overlapping portion in the lateral direction, and the strength of the connecting portion is increased.
[0015]
Further, since the overlapping portion and the fastening member are provided with the engaging portion and the engaging portion that are fitted to each other, the coupling strength with the fastening member is also increased, and the strength against the compressive load is increased.
[0016]
According to the second aspect of the present invention, in addition to the above action, the engaging portion and the engaging portion are formed with irregularities, so that the connection strength can be reliably increased with a simple structure.
[0017]
According to the third aspect of the present invention, in addition to the above action, the outriggers protrude outward in a substantially horizontal direction during use, so that even if the installation surface is uneven, the stepladder can be stably provided. Can be used. When the outrigger is not in use, the outrigger can be stored in a state parallel to the support leg 1 if it is slid upward, and is convenient for storage because it does not protrude outward.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a front view showing an embodiment of a stepladder according to the present invention, FIG. 2 is a partially cutaway front view of a connecting portion between an upper main leg and a lower main leg, which is a main part of the stepladder, and FIG. 3 is a side view of the stepladder. 4 and 4 are side views of a connecting portion between the upper main leg and the lower main leg, which are the main parts of the same, and the basic configuration of the stepladder of the present invention is the same as that of the conventional example shown in FIGS. The same reference numerals are assigned to the components.
[0019]
The stepladder of the present invention also has a ladder frame 3 formed by attaching a plurality of step bars 2 at appropriate intervals between a pair of support legs 1, and extending a handrail support 21 upward from the upper end of the support legs 1. Positioned at the upper end of the leg 1, a tread 6 is rotatably mounted between the opposing ladder frames 3 and 3, and both the column leg 1 and the handrail column 21 are made of, for example, an aluminum alloy. It was formed in a U-shaped cross section.
[0020]
The support leg 1 is divided into an upper main leg 1a and a lower main leg 1b, and superposed so that the lower outer surface of the upper main leg 1a and the upper inner surface of the lower main leg 1b can be joined to form superposed portions 7a and 7b. The upper end of the overlapping portion 7b of the lower main leg 1b is positioned at the upper end of the overlapping portion 7a of the upper main leg 1a by the rotating metal fitting 8 and is pivotally attached to the outside so as to be rotatable upward. Thereby, the lower main leg 1b is rotatably connected to the upper main leg 1a in a state where the overlapping portions 7a and 7b are overlapped.
[0021]
In the figure, reference numeral 9 denotes a fastening member for fastening the lower ends of the overlapping portions 7a and 7b, which is composed of an attachment member 20 and a fastening member 10, and the attachment member 20 is formed in a flat plate shape and is formed by a screw 13 with the upper main leg 1a. The fastening member 10 is pivotally attached to the lower portion of the mounting member 20 with a hinge 12 so as to be rotatable in the vertical direction.
[0022]
As shown in FIG. 5, the fastening member 10 is formed by overlapping a part of a pair of L-shaped metal fittings 10a and 10b and combining them in a slidable manner to form a flat U-shape. The lever 14 is provided eccentrically. An eccentric cam 14a coupled to the other metal fitting body 10b is built in, and the other metal fitting body 10b slides with respect to one metal fitting body 10a by the rotation of the lever 14.
[0023]
And in the latching | locking part of the fastening metal fitting 9 and the support | pillar leg 1, the protruding item | line 15 as a latching part is formed in the horizontal direction on the outer surface of the superposition | polymerization part 7a, 7b side, and the metal strip | board main body 10a, 10b side is formed. Grooves 16 that fit into the ridges 15 were formed on the inner surface of the ridges. The ridges 15 and the grooves 16 may be formed with the ridges 15 on the fastening bracket 9 side and the grooves 16 on the support leg 1 side.
[0024]
As shown in FIGS. 6 to 8, the outrigger 17 is attached to the lower part of the lower main leg 1 b of the support leg 1. The outrigger 17 has a main body formed in a channel shape, and is pivotally attached to a channel-shaped mounting bracket 18 fixed to the outside of the lower main leg 1b with a pin 19 so as to be pivotable in the vertical direction. Both ends of the pin 19 were inserted into an elongated hole 17a formed on the side surface of the portion, and pivotally attached to the mounting bracket 18 so as to be slidable in the vertical direction.
[0025]
Next, the usage will be described. In the storage state when not in use, the ladder frame 3 is folded up and down, and the lower main leg 1b rotates upward and is folded in parallel to the outside of the upper main leg 1a. Further, the width stop member 5 and the tread plate 6 are also folded around the center pivoting portion, and are accommodated between the opposed upper main legs 1a. The opposed upper main legs 1a, 1a are mutually connected via the rotating metal fitting 11. Close and folded in parallel.
[0026]
In order to use the stepladder from this state, the lower main leg 1b is rotated downward about the rotary fitting 8. Thereby, the lower main leg 1b protrudes below the upper main leg 1a in a state where the overlapping part 7b of the lower main leg 1b is overlapped on the outer side of the overlapping part 7a of the upper main leg 1a. At this time, the fastening member 10 of the fastening fitting 9 is lifted upward with the hinge 12 as an axis so that the lower main leg 1b does not hit the fastening member 10.
[0027]
When the overlapping portions 7a and 7b are overlapped as described above, the fastening member 10 is rotated downward to fit one metal fitting body 10a to the overlapping portion 7a, and the other metal fitting body 10b is connected to the overlapping portion 7b. And the lever 14 is further rotated to draw the metal fitting body 10b toward the metal fitting body 10a.
[0028]
The overlapping portion 7b is attracted to the overlapping portion 7a by the tightening force so that the overlapping portions 7a and 7b are integrated, and the protrusion 15 formed on the overlapping portions 7a and 7b is formed on the fastening member 10. Mates with groove 16
[0029]
In this way, the connecting portion between the upper main leg 1a and the lower main leg 1b is brought into a state where the side surfaces are in contact with each other at the overlapping portions 7a and 7b, and this portion is fastened. Therefore, the upper main leg 1a and the lower main leg 1b Are connected laterally. Therefore, there is no gap between the upper main leg 1a and the lower main leg 1b, and no play occurs. Moreover, the upper main leg 1a and the lower main leg 1b are integrated by the superposition | polymerization of a horizontal direction, and the intensity | strength of a connection part improves.
[0030]
Therefore, if the ladder frames 3 and 3 facing each other with the rotating metal fitting 11 at the upper end as an axis are opened, the step board 6 and the width stop material 5 extend, so that the work is performed on the step rail 2 or the step board 6. At this time, since the rattle does not occur at the connecting portion between the upper main leg 1a and the lower main leg 1b as described above, the tread 6 is not shaken and it is easy to work.
[0031]
Further, since the fastening fitting 9 and the support leg 1 are coupled by the fitting of the protrusion 15 and the groove 16, it is possible to exert a strong strength against an external force such as a compressive load applied to the support leg 1.
[0032]
Outrigger 17 is used when there is unevenness on the stepladder installation surface. When not in use, the outrigger 17 is housed in parallel with the outer side of the lower main leg 1b as shown in FIGS. In order to change the outrigger 17 from this stored state to the use state, as shown by the chain line in FIG. 9, if the outrigger 17 is pulled downward as it is, the elongated hole 17a slides along the pin 19 and the outrigger 17 descends.
[0033]
FIGS. 12 to 14 show the lowered position. If the outrigger 17 is rotated from the lowered position to the upper outside of the lower main leg 1b around the pin 19 as shown by a chain line in FIG. The use position shown in FIG. At this substantially horizontal position, the end of the outrigger 17 on the side of the lower main leg 1b comes into contact with the mounting bracket 18 to prevent further rotation.
[0034]
Therefore, if the lower main leg 1b and the outrigger 17 are grounded, the stepladder is installed in a stable state.
[0035]
In order to fold the stepladder after use, the outrigger 17 is accommodated on the outside of the lower main leg 1b in parallel with the above operation, and the lower main leg 1b is rotated upward to rotate the upper main leg. The leg 1a is accommodated in parallel with the outer side of the leg 1a, and the tread board 6 and the width stopper 5 are folded between the upper main legs 1a and 1a facing each other.
[0036]
When the extension leg 4 is provided, the outrigger 17 is attached to the lower end of the extension leg 4.
[0037]
【The invention's effect】
As described above, when the stepladder of the present invention is connected so that it can be folded by splitting the support leg of the stepladder vertically, the connecting portion is provided with a horizontal overlapping portion and connected at this portion. There is no gap between the two, and it is possible to prevent the play from occurring and to prevent the tread from shaking, thereby improving workability. In addition, the strength of the entire stepladder can be improved by increasing the connection strength and sufficiently supporting the load applied to the legs.
[Brief description of the drawings]
FIG. 1 is a front view showing an embodiment of a stepladder according to the present invention.
FIG. 2 is a partially cutaway front view of a connecting portion that is a main portion showing an embodiment of a stepladder according to the present invention.
FIG. 3 is a side view showing an embodiment of a stepladder according to the present invention.
FIG. 4 is a side view of a connecting portion which is a main part showing an embodiment of a stepladder according to the present invention.
FIG. 5 is a plan view of a fastener that is a main part showing an embodiment of a stepladder according to the present invention.
FIG. 6 is a front view of an outrigger which is a main part showing an embodiment of a stepladder according to the present invention.
FIG. 7 is a plan view of an outrigger which is a main part showing an embodiment of a stepladder according to the present invention.
FIG. 8 is a side view of an outrigger which is a main part showing an embodiment of a stepladder according to the present invention.
FIG. 9 is a front view of an outrigger that is a main part showing an embodiment of a stepladder according to the present invention.
FIG. 10 is a plan view when the outrigger, which is a main part showing the embodiment of the stepladder of the present invention, is stored.
FIG. 11 is a side view when the outrigger that is the main part showing the embodiment of the stepladder of the present invention is stored.
FIG. 12 is a front view when an outrigger that is a main part showing an embodiment of the stepladder of the present invention is pulled out;
FIG. 13 is a plan view when the outrigger, which is a main part showing the embodiment of the stepladder of the present invention, is pulled out.
FIG. 14 is a side view at the time of pulling out an outrigger which is a main part showing an embodiment of a stepladder according to the present invention.
FIG. 15 is a front view of a conventional stepladder.
FIG. 16 is a side view of a conventional stepladder.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Prop leg 2 ... Step 1a ... Upper main leg 1b ... Lower main leg 3 ... Ladder frame 4 ... Extension leg 5 ... Width stop material 6 ... Tread board 6a ... Tread board body 6b ... Stay 7 ... Horizontal brace 7a, 7b ... Superposition Part 8: Rotating bracket 9 ... Fastening bracket 10 ... Fastening member
10a, 10b ... metal fittings 11 ... rotating metal fittings
12 ... Hinge 13 ... Screw
14 ... Lever 15 ... Round
14a ... Eccentric cam
16 ... Groove 17 ... Outrigger
17a ... Elongated hole
18 ... Mounting bracket 19 ... Pin
20… Mounting member 21… Handrail support
30 ... Ladder frame 31 ... Connecting bracket

Claims (3)

A plurality of steps are attached between a pair of support legs at appropriate intervals to form a ladder frame. In a stepladder that is foldable, the support leg is composed of an upper main leg and a lower main leg that is pivotally connected to the upper main leg. A superposition part formed with a locking part on the side surface is provided, and the superposition part is fastened and fixed from the outside with a fastening bracket pivotally attached to either the upper main leg or the lower main leg. A stepladder characterized in that an engaging portion that engages with a locking portion formed in the overlapping portion is formed. The stepladder according to claim 1, wherein the locking portion and the engaging portion are formed with irregularities. The stepladder according to claim 1 or 2, wherein an outrigger that slides in a vertical direction and is rotatable in a substantially horizontal direction from a lower position is attached to a lower portion of the lower main leg.

Images