JP2016079714A - Step ladder, widening structure for ladder body, and manufacturing method for ladder body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide even more convenient and compact step ladder, expansion leg structure for a ladder body, and manufacturing method for the expansion leg.SOLUTION: A step ladder includes a laterally oriented tubular fixing tube fixed between a pair of support posts on right and left of a ladder body, a tubular first expansion/contraction tube housed in the fixing tube from an opening of the fixing tube, the first expansion/contraction tube expanding from and contracting into the opening, and a tubular second expansion/contraction tube housed in the fixing tube from the other opening of the fixing tube, the second expansion/contraction tube expanding from and contracting into the other opening. The step ladder has the first expansion/contraction tube and the second expansion/contraction tube nested and overlapped with each other inside the fixing tube, at least partially of the first expansion/contraction tube and the second expansion/contraction tube.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a stepladder, a ladder body widening structure, and a method of manufacturing a ladder body.

  A ladder apparatus having a ladder body such as a ladder, a stepladder, and a work bench is constructed by laying a plurality of step bars oriented in a direction substantially orthogonal to the column between a pair of left and right columns arranged side by side. Therefore, it generally has a long shape that is long in the extending direction of the support column (hereinafter referred to as the vertical direction) and short in the extending direction of the step rail (hereinafter referred to as the horizontal direction).

  For this reason, when the ladder device is installed in a leaning manner on the object, there is a problem that the stability of the ladder device is lowered depending on the position where the load of the user or the like is applied, and there is a possibility of the side rollover. In addition, depending on the level and flatness of the ground or the like on which the ladder device is installed, there is a problem that the stability of the ladder device is lowered even when there is no load. As a technique for solving such a problem related to the instability of the ladder device, techniques of Patent Documents 1 and 2 are disclosed.

  Patent Documents 1 and 2 disclose a ladder device in which an outrigger structure is provided at a lower portion of the ladder device, and a rectangular tubular member extending in a lateral direction is installed between a pair of left and right columns extending vertically. The inside of the shaped member is divided into two front and rear chambers (front cylinder part and rear cylinder part) by a partition wall extending in the lateral direction. The front cylinder part accommodates the arm part of the left telescopic arm, and the rear cylinder part accommodates the arm part of the right telescopic arm. In the ladder device configured as described above, the stability of the ladder device can be improved by pulling out the left and right extendable arms as necessary to widen the lower portion of the ladder device.

Japanese Utility Model Publication No. 6-20899 Utility Model Registration No. 3040689

  In the above-described conventional ladder device, the left and right extendable arms have arm portions that can be extended and retracted from the left and right tube portions, respectively, and leg portions that extend in the vertical direction connected to the respective arm portions. The lower end of the section constitutes the lower end of the leg of the ladder device.

  At this time, since the left telescopic arm is housed in the front tube portion and the right telescopic arm is housed in the rear tube portion, the cores of the arm portions of the left and right telescopic arms are displaced back and forth. For this reason, when the ladder device is used tilted in the front-rear direction, the height of the lower end of the leg extending from the left and right telescopic arms will shift according to the tilt in the front-rear direction, and there is no height adjustment function for the lower end of the leg part. There was a problem that the ladder device tilted to the side and the stability was lost.

  In addition, since the front cylinder part that accommodates the arm part of the left telescopic arm and the rear cylinder part that accommodates the arm part of the right telescopic arm are arranged side by side, the rectangular cylindrical member is the arm of the telescopic arm. It will have a front and rear width of two or more parts. For this reason, there is a possibility that the front-rear width of the rectangular tubular member is wider than the front-rear width of the support column, and in this case, there is a problem that the rectangular cylindrical member has a protruding shape so as to protrude forward and backward from the support column. It was. Furthermore, when the height of the outrigger structure is increased to increase the strength, there is a problem that the width and height increase and the weight increases.

  The present invention has been made in view of the above problems, and an object thereof is to provide a more convenient and compact stepladder, a ladder widening structure, and a method of manufacturing a ladder.

  One aspect of the present invention includes a tubular fixed tube that is fixed in a horizontal direction between a pair of left and right support columns of a ladder body, and is accommodated in the tube from one opening of the fixed tube. A telescopic tubular first telescopic tube; and a tubular second telescopic tube accommodated in the tube through the other opening of the fixed tube and telescopic from the other opening, the first telescopic tube and the first telescopic tube The two telescopic tubes are stepladders that can be accommodated in the fixed tube in a state where at least a part of the first telescopic tube and the second telescopic tube overlap each other.

  Since the first telescopic tube and the second telescopic tube can be accommodated in a state of being nested in the fixed tube in this way, the telescopic lengths of the first telescopic tube and the second telescopic tube are set to the fixed tube. The length of the fixed tube can be approximately the same as the length of the tube, and the thickness of the fixed tube can be about one of the first and second telescopic tubes, so that the fixed tube protrudes forward and backward. There is no need to have a protruding shape. Thereby, it is easy to use and a compact stepladder can be realized.

  Also, one of the optional aspects of the present invention is that the state in which at least a part of the first telescopic tube and the second telescopic tube overlap each other in the fixed tube is the second telescopic tube. Is a mode in which at least a part of the first telescopic tube is accommodated therein, and an outer shape of the first telescopic tube substantially matches an inner shape of the second telescopic tube, and the fixing of the first telescopic tube is performed. The inner end on the tube side is a stepladder characterized in that the outer diameter of the tube decreases as the inner end approaches.

  Thus, by making the outer diameter of the inner end portion of the first telescopic tube on the fixed tube side closer to the inner end, at least the first telescopic tube and the second telescopic tube are included in the fixed tube. When the parts of the first telescopic tube are accommodated in a state of overlapping each other in a nested manner, the inner end of the first telescopic tube is smoothly inserted into the second telescopic tube, and the first telescopic tube and the second telescopic tube are connected. The workability of the work accommodated in the fixed pipe is improved.

  Also, one of the optional aspects of the present invention is that the state in which at least a part of the first telescopic tube and the second telescopic tube overlap each other in the fixed tube is the second telescopic tube. Is a mode in which at least a part of the first telescopic tube is accommodated therein, and an outer shape of the first telescopic tube substantially coincides with an inner shape of the second telescopic tube, and the one opening of the fixed tube A stepladder characterized in that at least a part of the inner shape near the inner diameter is reduced in diameter compared to the inner shape near the other opening of the fixed tube.

  Thus, by reducing the diameter of at least a part of the fixed tube at a position near the one opening where the first telescopic tube enters and exits, the gap between the fixed tube and the first telescopic tube is reduced, and the first tube in the fixed tube is reduced. 1 Shaking of the telescopic tube can be suppressed. Thereby, the unintentional inclination to the left-right direction of the ladder body of a stepladder is suppressed, and the usability of the stepladder comprised compactly can be improved further.

  Also, one of the selective aspects of the present invention is that a guide groove is provided along the expansion / contraction direction of the inner surface of the second expansion tube, and along the expansion / contraction direction of the outer surface of the first expansion tube. The step is characterized in that a guide protrusion is provided to engage with the guide groove.

  Thus, by providing the guide protrusion and the guide groove that engage with each other between the first expansion tube and the second expansion tube, at least a part of the first expansion tube can be expanded and contracted in the fixed tube. When accommodated in the inside of the tube, the first telescopic tube can be smoothly slid in the second telescopic tube.

  One of the optional aspects of the present invention is that the outer end of the first telescopic tube and the second telescopic tube opposite to the fixed tube has legs extending downward from the outer end. The stepladder is characterized in that each of the telescopic legs is adjustable in length.

  In this way, the length of the leg is adjusted according to the inclination and shape of the installation surface of the stepladder by providing the extensible leg at the outer end opposite to the fixed pipe of the first and second telescopic pipes. Thus, the posture of the stepladder can be adjusted appropriately.

  One of the selective aspects of the present invention is that the telescopic legs are arranged in an outer cylinder portion fixed to the outer end portion with a cylindrical axis oriented in a substantially vertical direction, and in the cylinder of the outer cylinder portion. An inner cylinder portion inserted through the lower cylinder portion, a multi-thread screw inserted into the outer cylinder portion, and a rotation operation portion fixed to an upper end portion of the multi-thread screw; A female screw part that is screwed into the multi-threaded screw is provided at the upper part, and the multi-threaded screw is fixed to the outer cylinder part so as to be rotatable about the shaft, and is accompanied by a rotation operation of the rotation operating part. The stepladder is characterized in that the outer tube portion slides relative to the inner tube portion by rotating the shaft of the multi-thread screw.

  Thus, by making the leg length of the extendable leg adjustable by rotating the screw, an extendable leg structure with high leg length adjustment accuracy can be realized.

  One of the optional aspects of the present invention is that the telescopic leg has an insertion part provided at the outer end with the direction of the insertion hole oriented substantially in the vertical direction, and a length in the insertion hole. A linear vertical member inserted with its direction oriented substantially in the vertical direction, a plate member disposed in the insertion hole, and an operation unit for adjusting the interval between the vertical member and the plate member And a first concavo-convex engaging surface is formed along the longitudinal direction on the side surface of the vertical member, and the plate member has a second concavo-convex engaging surface on the side facing the vertical member. When the first concavo-convex engagement surface and the second concavo-convex engagement surface are in contact, sliding movement of the vertical member in the insertion portion is restricted, and the first concavo-convex engagement surface and the second In the stepladder, the regulation of the sliding movement of the vertical member in the insertion portion is released when the uneven engagement surface is separated. That.

  By using the vertical member inserted into the insertion hole in this way as an extension / contraction leg, the length of the leg of the extension / contraction leg is adjusted by the concavo-convex engagement between the concavo-convex engagement surfaces. Adjustment time is short. That is, in the adjustment of the leg length using the screw rotation as described above, the length of the leg is gradually changed by continuous screw rotation. The engagement surface and the second concavo-convex engagement surface are separated from each other, the restriction of the sliding movement of the vertical member is released, and the vertical member is slid to a desired position to engage the first concavo-convex engagement surface and the second concavo-convex engagement. The length of the leg of the telescopic leg can be adjusted simply by bringing the surface into contact and regulating the sliding movement of the vertical member.

  One of the selective aspects of the present invention is that the plate member is formed of a plurality of joint members oriented in a downwardly inclined manner from the inner wall of the insertion hole toward the plate member and the plate. The stepladder is characterized in that it is connected to the inner wall of the insertion portion by a parallel link mechanism configured by connecting the back surface of the member opposite to the second uneven engagement surface.

  In this way, the inner wall of the insertion portion and the second concave and convex engagement surface of the plate member are opposite to each other using the parallel link mechanism configured by the plurality of joint members oriented in a downwardly inclined manner from the inner wall of the insertion hole toward the plate member. The first uneven engagement surface and the second uneven engagement surface with respect to the sliding movement in the insertion hole of the vertical member in the direction of shortening the length of the leg of the telescopic leg by connecting the back surface on the side. While the force that presses the mating surfaces against each other works to increase the concave-convex engagement force between these surfaces, the sliding movement in the insertion hole of the vertical member in the direction of extending the length of the leg of the telescopic leg is the first. The structure which weakens the uneven | corrugated engagement force between the 1 uneven | corrugated engagement surface and the 2nd uneven | corrugated engagement surface will be implement | achieved.

  One of the selective aspects of the present invention is that the plate member is biased by a spring member in a direction in which the first uneven engagement surface and the second uneven engagement surface are brought closer to each other. It is a featured stepladder.

  In this way, the spring member is biased in a direction in which the first uneven engagement surface and the second uneven engagement surface are brought closer to each other, so that the spring member has the first uneven engagement surface and the second uneven engagement surface. Stress is always applied in the direction in which the first and second concave and convex engaging surfaces are separated from each other, and the operation of the vertical member in the insertion portion is performed except when an operation of separating the first and second concave and convex engaging surfaces is performed. The sliding movement is restricted. Thereby, fixation of the length of the leg of an expansion-contraction leg can be stabilized.

  One of the selective aspects of the present invention is that the operation portion is formed to extend from a shaft portion on the inner wall side of the insertion portion of the joint member, and the spring member includes the operation portion. A stepladder characterized in that it is urged in a direction to separate the operation portion and the back surface of the plate member.

  In this way, the operation unit for adjusting the interval between the vertical member and the plate member by the parallel link mechanism is urged by the spring member in the direction in which the interval between the vertical member and the plate member approaches, so that the operation unit is When the operation of separating the interval between the vertical member and the plate member is performed, the operation force acts as an operation force for simultaneously releasing the biasing of the spring member in the direction in which the interval between the vertical member and the plate member approaches. It becomes. Thereby, the operativity of the operation part for performing the restriction | limiting of the sliding movement of the vertical member in the insertion part, and the cancellation | release of the said restriction | limiting can be improved.

  One of the other aspects of the present invention is a tubular fixed tube that is fixed in a horizontal direction between a pair of left and right columns of a ladder, and is accommodated in the tube through one opening of the fixed tube. A first telescopic tube that is telescopic from one opening, and a second tubular telescopic tube that is accommodated in the tube from the other opening of the fixed tube and is telescopic from the other opening. The ladder and the second telescopic tube can be accommodated in the fixed tube in a state where at least a part of the first telescopic tube and the second telescopic tube overlap each other in a nested manner. This is a telescopic leg structure. That is, the above-described configurations and operational effects are not limited to the case where a stepladder is provided, and the various configurations described above are applied to various ladder devices having a ladder configuration in which a crosspiece is horizontally mounted between a pair of support columns. Even if it is a case, there exists the same effect.

Also, one of the selective aspects of the present invention is the step of fixing a tubular fixed tube by being oriented left and right between a pair of left and right struts of the ladder, and fixing the tubular first telescopic tube to the fixed portion. A step of accommodating the tube from one opening of the tube so as to be extendable and retractable from the one opening, and a tubular second telescopic tube being accommodated from the other opening of the fixed tube to the tube and retractable from the other opening The first telescopic tube and the second telescopic tube in the fixed tube, and at least a part of the first telescopic tube and the second telescopic tube overlap each other in a nested manner. It is a manufacturing method of the expansion-contraction leg characterized by being accommodated in the state which carried out. That is, it goes without saying that the present invention can also be realized as a method for manufacturing a telescopic leg having a process corresponding to the configuration of each device described above.

  According to the first, eleventh and twelfth aspects of the present invention, the first telescopic tube and the second telescopic tube are configured to be accommodated in a state where they are nested in the fixed tube. 2 The telescopic length of the telescopic tube can be set to the same length as that of the stationary tube, and the thickness of the stationary tube can be about one of the first telescopic tube and the second telescopic tube. For this reason, it is not necessary to have a shape in which the fixed tube protrudes forward and backward. Thereby, it is easy to use and a compact stepladder can be realized.

  According to the second aspect of the present invention, the outer diameter of the inner end of the first expansion tube on the fixed tube side is reduced in diameter as it approaches the inner end, so that the first expansion and contraction in the fixed tube. When at least a part of the tube and the second telescopic tube are accommodated in a state where they are nested, the inner end of the first telescopic tube is smoothly inserted into the tube of the second telescopic tube, The workability of the work of accommodating the first telescopic tube and the second telescopic tube in the fixed tube is improved.

  According to the invention of claim 3, the fixed tube and the first telescopic tube are reduced by reducing the diameter of at least a part of the fixed tube at the position near the one opening where the first telescopic tube enters and exits. The gap between the first and second telescopic tubes can be prevented from rattling in the fixed tube. Thereby, the unintentional inclination to the left-right direction of the ladder body of a stepladder is suppressed, and the usability of the stepladder comprised compactly can be improved further.

  According to a fourth aspect of the present invention, a guide protrusion and a guide groove that engage with each other are provided between the first expansion tube and the second expansion tube, thereby providing the first expansion and contraction in the fixed tube. When at least a part of the tube is accommodated in the second telescopic tube, the first telescopic tube can be smoothly slid in the second telescopic tube.

  Moreover, according to the invention concerning Claim 5, by providing an extensible leg on the outer end of the first telescopic tube and the second telescopic tube opposite to the fixed tube, the inclination state and shape of the installation surface of the stepladder can be obtained. Accordingly, the leg length can be adjusted to appropriately adjust the posture of the stepladder.

  According to the sixth aspect of the invention, by making the length of the leg of the telescopic leg adjustable by rotating the screw, it is possible to realize a telescopic leg structure with high leg length adjustment accuracy.

  According to the invention of claim 7, the vertical member inserted into the insertion hole is used as an extensible leg, and the length of the leg of the extensible leg is adjusted by the irregular engagement between the irregular engagement surfaces. By doing so, the adjustment time of the leg length can be completed in a short time. That is, in the adjustment of the leg length using the screw rotation, the length of the leg is gradually changed by continuous screw rotation. In the aspect of the present invention, the first uneven engagement is performed. The first uneven engagement surface and the second uneven engagement surface are separated by separating the surface and the second uneven engagement surface to release the restriction of the sliding movement of the vertical member and sliding the vertical member to a desired position. The length of the leg of the telescopic leg can be adjusted only by restricting the sliding movement of the vertical member by making contact.

  Further, according to the invention according to claim 8, the inner wall of the insertion portion and the plate member are formed by using a parallel link mechanism constituted by a plurality of joint members oriented downwardly inclined from the inner wall of the insertion hole toward the plate member. By connecting between the back surface opposite to the second concavo-convex engaging surface, the first movement against the sliding movement in the insertion hole of the vertical member in the direction of shortening the length of the leg of the telescopic leg is the first. While increasing the concave-convex engagement force between the concave-convex engagement surface and the second concave-convex engagement surface, the first concave-convex engagement regarding the sliding movement in the insertion hole of the vertical member in the direction of extending the length of the leg of the telescopic leg. A structure that weakens the concave-convex engaging force between the mating surface and the second concave-convex engaging surface is realized.

  According to the invention of claim 9, the spring member is biased in the direction in which the first uneven engagement surface and the second uneven engagement surface are brought closer by the spring member, so that the spring member is engaged with the first uneven engagement surface. When a stress is always applied in the direction in which the surface and the second concavo-convex engagement surface come into contact with each other, and an operation for separating the first concavo-convex engagement surface and the second concavo-convex engagement surface is performed on the operation unit Other than the above, the sliding movement of the vertical member in the insertion portion is restricted. Thereby, fixation of the length of the leg of an expansion-contraction leg can be stabilized.

  According to the invention of claim 10, the operation part itself for adjusting the interval between the vertical member and the plate member by the parallel link mechanism is attached by the spring member in the direction in which the interval between the vertical member and the plate member approaches. When the operation is performed so that the interval between the vertical member and the plate member is separated from the operation unit, the operation force is simultaneously urged by the spring member in the direction in which the interval between the vertical member and the plate member approaches. It will act as an operating force to cancel. Thereby, the operativity of the operation part for performing the restriction | limiting of the sliding movement of the vertical member in the insertion part, and the cancellation | release of the said restriction | limiting can be improved.

It is the figure which looked at the stepladder concerning this embodiment from diagonally. It is the figure which looked at the stepladder concerning this embodiment from diagonally. It is the figure which showed the stepladder concerning this embodiment seeing from the front. It is the figure which looked at the outrigger structure of the stepladder from an angle. It is the figure which looked at the outrigger structure of the stepladder from an angle. It is the figure which looked at the outrigger structure of the stepladder from an angle. It is the figure which showed the outrigger structure of the stepladder seeing from the front. It is the figure which showed the outrigger structure of the stepladder seeing from the front. It is the figure which fractured | ruptured a part of fixed tube and showed the state of the expansion-contraction tube inside. It is the figure which showed the telescopic leg structure of the left leg part seen from diagonally. It is the perspective view which decomposed | disassembled the expansion-contraction leg structure and showed the assembly state. It is sectional drawing of an expansion-contraction leg structure. It is sectional drawing which shows the operation state of an expansion-contraction leg structure. It is sectional drawing which shows the modification of an expansion-contraction leg structure. It is sectional drawing which shows the other modification of an expansion-contraction leg structure. It is the figure which looked and showed the outrigger part concerning 2nd Embodiment from the front. It is sectional drawing cut | disconnected and shown along the YY line shown in FIG. It is sectional drawing cut | disconnected and shown along the ZZ line | wire shown in FIG. It is a figure explaining the end tool shape provided in the lower end of the leg part of the outrigger part concerning 2nd Embodiment. It is a figure explaining the leg part of the stepladder concerning 3rd Embodiment. It is a figure explaining the outrigger part of the stepladder concerning 4th Embodiment. It is a figure explaining the fixing pipe of the stepladder concerning 5th Embodiment, and the support | pillar attachment member attached to this.

Hereinafter, the present invention will be described in the following order.
(1) First embodiment:
(2) Second embodiment:
(3) Third embodiment:
(4) Fourth embodiment:
(5) Fifth embodiment:

(1) First embodiment:
First, the structure of the stepladder 1 which concerns on this embodiment is demonstrated, referring FIGS. 1-3. FIG. 1 and FIG. 2 are views showing each step of the stepladder according to this embodiment as seen from an oblique direction, and FIG. 3 is a view showing the stepladder according to this embodiment as seen from the front. As shown in FIGS. 1-3, the stepladder 1 which concerns on this embodiment is a ladder combined stepladder used also as a ladder, and is provided with a pair of ladder bodies 2 which have a mutually common structure.

  The ladder body 2 includes a pair of left and right support columns 3 that are vertical members, and a plurality of step bars 4 that are horizontally mounted between the pair of support columns 3 that are disposed at a predetermined interval.

  In the ladder body 2, a direction in which the pair of support columns 3 face each other, that is, a direction in which the step rail 4 is horizontally mounted (a horizontal direction in FIG. 1) is defined as a horizontal direction. In the ladder body 2, the pair of support columns 3 are configured symmetrically in the left-right direction.

  Each column 3 is a member made of metal such as aluminum or aluminum alloy, for example, and a vertical portion 3a parallel to each other in relation to the other column 3 and the other column 3 provided below the vertical portion 3a. Therefore, the inclined portion 3b gradually widens as the distance between the pair of support columns 3 approaches downward.

  That is, as shown in FIG. 3, the stepladder 1 has a shape in which the interval between the pair of support pillars 3 gradually expands from the upper side to the lower side in the inclined portion 3 b. In the present embodiment, in the support column 3, the upper 1/3 to 1/4 portion constituting the upper portion of the ladder body 2 constitutes the vertical portion 3a, and the remaining lower portion constitutes the inclined portion 3b. To do.

  The inclined portion 3b is arranged in an inclined manner with a predetermined angle α so as to spread outward with respect to the extending direction of the vertical portion 3a. Between the pair of struts 3 having such a configuration, the upper vertical portions 3a are parallel to each other, and the inclined portions 3b on the lower side thereof are substantially "C" -shaped so as to expand downward in a front view. Make.

  In the following description, the extending direction of the vertical portion 3a of the column 3 is the vertical direction of the ladder body 2, the inclined portion 3b side with respect to the vertical portion 3a is the lower side, and the opposite side is the upper side.

  The support | pillar 3 is a longitudinal member which has a U-shaped cross-sectional shape. The pair of support columns 3 are provided in a state where the side wall portion 3c side of the U-shaped cross-sectional shape is the inside, and the open side of the U-shaped cross-sectional shape is directed left and right. For example, the support column 3 is formed by cutting a linear extruded product having a U-shaped cross section into a predetermined length and then bending and molding it at a predetermined position corresponding to the boundary between the vertical portion 3a and the inclined portion 3b. Is done. An outrigger portion 10 to be described later is attached and fixed to the lower end portion of the column 3.

  The crosspiece 4 is, for example, a metal member such as aluminum or an aluminum alloy, and is a linear member having the installation direction with respect to the pair of columns 3 as a longitudinal direction. The crosspiece 4 is configured by, for example, a linear extruded product having a predetermined cross-sectional shape being cut into a predetermined length and a member subjected to a predetermined processing is installed between a pair of columns 3. The The step rail 4 is installed between the pair of support columns 3 and between the vertical portions 3a and between the inclined portions 3b.

  In this embodiment, between the pair of support columns 3, a total of five step bars 4, two between the vertical portions 3 a and three between the inclined portions 3 b, are spaced at substantially equal intervals in the vertical direction of the ladder body 2. Is provided.

  The two step bars 4 installed between the vertical portions 3a have the same length (dimension in the longitudinal direction). Of the two step bars 4 installed between the vertical parts 3 a, the upper step bar 4 is installed between the upper ends of the vertical parts 3 a, that is, between the upper ends of the columns 3. The length of the three traversing bars 4 installed between the inclined portions 3b is longer as the traversing rails 4 arranged on the lower side according to the interval between the pair of inclined portions 3b. The five crosspieces 4 have a common configuration other than the length, specifically, a cross-sectional shape and an end shape in the longitudinal direction, which will be described later.

  The ladder body 2 constituted by the support column 3 and the traverse 4 as described above makes a pair, and the upper end portions that are narrower with respect to the lower portion are connected to each other via a joint fitting 6 that is a connecting member. It is connected so that rotation is possible with the left-right direction as the rotation axis direction.

  The joint fitting 6 is provided at the upper end portion of each support column 3, and in a configuration in which the pair of ladder bodies 2 face each other, the support columns 3 on the common side in the left-right direction are provided at the upper end portions thereof. It is rotatably connected via a metal fitting 6.

  The joint bracket 6 is a member that forms a hinge portion between the columns 3 to be connected to each other. The corresponding columns 3 on the left and right sides of the stepladder 1 are connected to each other by the joint brackets 6 provided at the upper ends of the columns 3. By being connected so as to be rotatable with the left-right direction as the rotation axis direction, they are connected via a pair of joint fittings 6 so as to be rotatable. Thereby, the ladder bodies 2 are connected to each other so as to be rotatable with the left-right direction as the rotation axis direction.

  The joint fitting 6 is a plate-like member as a whole, and is fixed to the support column 3 and has a fixed portion 6a having a substantially rectangular outer shape. The joint fitting 6 protrudes from the fixed portion 6a and is connected to the counterpart joint fitting 6. And a hinge portion 6b which is a portion.

  In the joint fitting 6, the fixing portion 6 a is arranged along the surface on the inner side (the inner side in the left-right direction) of the side wall portion 3 c of the support column 3, that is, the surface opposite to the open side in the U-shaped cross section of the support column 3. In the state, it is fixed to the column 3 by a plurality of fixing members such as rivets.

  In a state where the joint fitting 6 is fixed to the column 3, the hinge portion 6 b protrudes toward the other column 3 to be connected. Between the struts 3 connected to each other by the joint metal fittings 6, the overlapping portions of the hinge portions 6 b of the respective joint metal fittings 6 are connected to each other by a pivotal support member such as a pivot pin so as to be relatively rotatable. The support columns 3 are rotatably connected to each other through the joint fitting 6 fixed to the bracket.

  In this way, in the stepladder 1 having a configuration in which the pair of ladder bodies 2 are connected to each other with the left-right direction as the rotational axis direction, the left and right sides are prevented from being opened between the columns 3 connected to each other via the joint metal fitting 6. A metal fitting 8 is provided. When the stepladder 1 serving also as a ladder is used as a stepladder, the opening stopper 8 restricts the rotation in the opening direction of the ladder bodies 2 by being bridged between the upper ends of the columns 3.

  That is, when the stepladder 1 is used as a stepladder, the pair of ladder bodies 2 are substantially inverted V-shaped along the hypotenuse of an isosceles triangle whose apex side is the rotation center side by the shaft support member when viewed from the side by the column 3. In this state, the opening stopper 8 is bridged between the upper ends of the support columns 3 in a substantially horizontal direction, so that the opening of the ladder bodies 2 between the predetermined amounts is restricted. .

  More specifically, the stopper metal fitting 8 is of a folding type made of two elongated rectangular (strip-shaped) plate-like members whose ends are connected to each other so as to be relatively rotatable. The opening stopper 8 has an end on one side thereof, that is, an end of one plate-like member opposite to the connection side with respect to the other plate-like member is pivotable to a predetermined position on the upper end of the column 3. It is provided in a supported state.

  Then, in the state where the stepladder 1 is used as a stepladder, the other end of the stopper metal fitting 8 is fitted with a locking recess such as a locking pin provided on the column 3 side, for example, The column 3 is locked at a predetermined position at the upper end of the column 3. As a result, the opening stoppers 8 are in a state of being spanned between the columns 3 in a linear manner along the horizontal direction on both the left and right sides of the stepladder 1, and stop the ladder bodies 2 from opening.

  The stepladder 1 of the present embodiment having the above-described configuration is configured to be foldable so that a pair of ladder bodies 2 connected to each other via a joint fitting 6 so as to be rotatable are substantially parallel to each other in a side view. ing. In the folded state of the stepladder 1, the center folding-type stopper 8 is bent in a substantially inverted V shape by the rotation of the two plate members between the ladder bodies 2 that are substantially parallel to each other.

  When the stepladder 1 is used as a stepladder, as described above, the pair of ladder bodies 2 has a substantially inverted V shape in a side view and is in a state of being opened by a predetermined amount (see FIG. 1). In the stepladder state of the stepladder 1, the opening stopper 8 restricts the opening of the ladder bodies 2 by a predetermined amount or more.

  On the other hand, when used as a ladder, the stepladder 1 is in an open state until the restriction of the rotation by the stopper metal fitting 8 is released and the pair of ladder bodies 2 are straight in a side view.

  In the ladder state of the stepladder 1, the support columns 3 connected to each other through the joint metal fitting 6 are in a state of being continuous with each other so that the upper ends thereof are in contact with each other so as to be straight in a side view. Become. That is, the ladder-like stepladder 1 has a length (height) twice that of the ladder body 2. In the ladder-like stepladder 1, the stopper metal fitting 8 is placed between the support columns 3 along the linear direction between the support columns 3 that are linearly connected to each other. It functions to fix and hold.

  Next, the outrigger structure of the stepladder 1 will be described with reference to FIGS. 4 to 6 are views showing the outrigger structure of the stepladder 1 from an oblique direction, FIGS. 7 and 8 are views showing the outrigger structure of the stepladder 1 from the front, and FIG. It is the figure which fractured | ruptured some and showed the state of the internal expansion-contraction pipe | tube.

  The outrigger portion 10 of the stepladder 1 is a fixed tube 11 that is fixed in a horizontal direction between a pair of support columns 3. The outrigger portion 10 is accommodated in the tube from one opening of the fixed tube 11. 1. A left telescopic tube 12 as a telescopic tube, a left leg 13 extending downward from the left end of the left telescopic tube 12, and a tubular tube that is accommodated in the tube from the other opening of the fixed tube 11 and is telescopic from the other opening. A right telescopic tube 14 serving as a second telescopic tube, and a right leg 15 extending downward from the right end of the right telescopic tube 14 are provided. In the state where the left telescopic tube 12 and the right telescopic tube 14 are maximally accommodated in the fixed tube 11, the left leg portion 13 and the right leg portion 15 enter the concave portion of the U-shaped cross section of the column 3 and the column 3 It will be in the state extended substantially continuously downward from.

  The fixed tube 11 is a member made of metal such as aluminum or aluminum alloy, and is a straight tube member whose longitudinal direction is the installation direction with respect to the pair of columns 3. The fixed tube 11 is configured by connecting a linear extruded product having a predetermined cross-sectional shape to a predetermined length by cutting a linear extruded product into a lower portion of a pair of columns 3. . The fixed tube 11 and the column 3 are connected to each other using a connecting member 16 fixed to the left and right ends of the fixed tube 11.

  A left opening 11 a is provided at the left end of the fixed tube 11, and a left telescopic tube 12 is inserted into the tube of the fixed tube 11 from the left opening 11 a. Similarly, a right opening 11 b is provided at the right end of the fixed tube 11, and a right telescopic tube 14 is inserted into the tube of the fixed tube 11 from the right opening 11 b.

  The left telescopic tube 12 and the right telescopic tube 14 are metal members such as aluminum or aluminum alloy, and are linear tube members having the same direction as the longitudinal direction of the fixed tube 11 as the longitudinal direction.

  The left telescopic tube 12 and the right telescopic tube 14 are members in which a linear extruded product having a predetermined cross-sectional shape is cut into a predetermined length and subjected to a predetermined processing. 11 is inserted into the tube through the left opening 11a, and the right telescopic tube 14 is configured to be inserted into the tube through the right opening 11b of the fixed tube 11.

  A retaining structure is provided between the fixed tube 11 and the left telescopic tube 12 and between the fixed tube 11 and the right telescopic tube 14, and the fixed tube 11 overlaps with the left telescopic tube 12 and the right telescopic tube 14. The range is regulated not to fall below a certain amount. Thereby, the left telescopic tube 12 and the right telescopic tube 14 are prevented from being detached from the fixed tube 11.

  The left telescopic tube 12 and the right telescopic tube 14 have at least a half length in the longitudinal direction of the fixed tube 11 in the longitudinal direction, and can be accommodated in the fixed tube 11 substantially in their entirety. The left telescopic tube 12 and the right telescopic tube 14 may be configured to have substantially the same length as the fixed tube 11. Thereby, the range which can be expanded-contracted by pulling out the left expansion tube 12 and the right expansion tube 14 from the fixed tube 11 can be lengthened.

  The right telescopic tube 14 has an outer shape in a cross-sectional shape substantially equal to or slightly smaller than an inner shape in a cross-section of the fixed tube 11. In particular, the right telescopic tube 14 has an upper surface and a lower surface of the outer shape in the cross-sectional shape that are substantially equal to or slightly smaller than the inner shape in the cross-section of the fixed tube 11. For this reason, the integral adhesion between the fixed tube 11 and the right telescopic tube 14 inserted into the tube of the fixed tube 11 is improved while allowing the right telescopic tube 14 to slide in the tube of the fixed tube 11.

  The left telescopic tube 12 has an outer shape in a cross-sectional shape substantially equal to or slightly smaller than an inner shape in the cross-sectional shape of the right telescopic tube 14. In particular, the left telescopic tube 12 has an upper surface and a lower surface of the outer shape in the cross-sectional shape substantially equal to or slightly smaller than the inner shape in the cross-section of the right telescopic tube 14. That is, the cross-sectional size of each tube is formed so as to gradually become smaller in the order of the fixed tube 11, the right telescopic tube 14, and the left telescopic tube 12. For this reason, the left telescopic tube 12 and the right telescopic tube 14 inserted into the tube of the fixed tube 11 are inserted inside the fixed tube 11 with the left telescopic tube 12 nested inside the tube of the right telescopic tube 14. An insertion state can be realized.

  This allows the left telescopic tube 12 to slide within the tube of the right tube 14 while allowing the left telescopic tube 12 to slide within the tube of the fixed tube 11. The integral adhesion between the right telescopic tube 14 and the left telescopic tube 12 inserted into the right telescopic tube 14 is improved while improving the integral adhesion with the inserted right telescopic tube 14. Further, the length of the left telescopic tube 12 and the right telescopic tube 14 in the longitudinal direction can be increased to approximately the same as the length of the fixed tube 11 in the longitudinal direction. The amount can be taken large. Further, in the fixed tube 11, the rigidity in the cross-sectional direction of the portion in which the left telescopic tube 12 and the right telescopic tube 14 are accommodated can be improved. In addition, since the left telescopic tube 12 and the right telescopic tube 14 can be accommodated in the fixed tube 11, the fixed tube 11 can be suppressed to a thickness about one of the left telescopic tube 12 and the right telescopic tube 14. it can.

  The inner shape of the cross-sectional shape of the fixed tube 11 is substantially equal to or slightly larger than the outer shape of the right telescopic tube 14, but the inner shape of the cross-sectional shape of at least a part of the fixed tube 11 near the left opening 11a. May be reduced in diameter compared to the inner shape in the cross-sectional shape of at least a part of the fixed tube 11 near the right opening 11b. For example, at least a part of the fixed tube 11 in the vicinity of the left opening 11 a is formed so that the inner shape in the cross-sectional shape is substantially equal to or slightly larger than the outer shape of the left telescopic tube 12 as compared with other parts of the fixed tube 11. May be. Specifically, for example, at least a part of the fixed tube 11 near the left opening 11a is reduced in diameter, or a thin insert is disposed along the inner surface of the fixed tube 11 near the left opening 11a. . As a result, in the left opening 11a of the fixed tube 11 through which the left telescopic tube 12 enters and exits, the gap formed between the outer surface of the left telescopic tube 12 and the inner surface of the fixed tube 11 is reduced, and the inside of the fixed tube 11 is reduced. The play of the left telescopic tube 12 can be optimized, and rattling of the left telescopic tube 12 in the fixed tube 11 can be prevented as much as possible.

  The cross-sectional shape at the distal end portion of the left telescopic tube 12 is formed in a tapered shape whose outer diameter is reduced as it approaches the inner end portion on the fixed tube 11 side. The tapered shape of the inner end portion can be realized, for example, by attaching and fixing a cap-shaped end tool 12g to the tip of the left telescopic tube 12. As a result, when the left telescopic tube 12 is inserted into the tube of the right telescopic tube 14 in the tube of the fixed tube 11, the collision between the inner end of the right telescopic tube 14 and the inner end of the left telescopic tube 12 is made as much as possible. This makes it easier to insert the right telescopic tube 14 into the left telescopic tube 12.

  In the present embodiment, the diameter reduction amount Δd1 at the tip of the left telescopic tube 12 is larger than the thickness Δd2 of the tube wall of the right telescopic tube 14. Therefore, when the left telescopic tube 12 is inserted into the right telescopic tube 14 in a state where the outer wall of the right telescopic tube 14 is in contact with the inner wall of the fixed tube 11, the tip of the left telescopic tube 12 is The distal end of the left telescopic tube 12 is guided into the tapered shape of the distal end and smoothly inserted into the tube of the right telescopic tube 14.

  Instead of making the inner end portion of the left telescopic tube 12 taper, the cross-sectional shape of the inner end portion of the right telescopic tube 14 on the fixed tube 11 side is enlarged so that the inner shape becomes larger toward the inner end. You may form in a radial shape, and you may combine making the inner end part of the left expansion-contraction tube 12 into a taper-shape, and making the front-end | tip part of the right expansion-contraction tube 14 into a diameter expansion shape. Even in this case, the inner end of the left telescopic tube 12 is smoothly inserted into the tube of the right telescopic tube 14.

  The fixed tube 11 is provided with a plurality of holes 11c and 11d penetrating the inside and outside of the tube, the left telescopic tube 12 is also provided with a plurality of holes 12a and 12b, and the right telescopic tube 14 is also provided with a plurality of holes. Holes 14a and 14b are provided.

  Locking devices 17 and 18 are fixed to the outer surfaces of the holes 11c and 11d of the fixed tube 11, respectively. The lock devices 17 and 18 are for advancing the locking projections into the pipes through the holes 11c and 11d. The maximum protrusion length of the locking projection into the fixed tube 11 is equal to or greater than the sum of the wall thickness of the fixed tube 11 and the wall surface of the right telescopic tube 14. As a result, the holes 14 a and 14 b of the right telescopic tube 14 and the holes 12 a and 12 b of the left telescopic tube 12 are overlapped with the holes 11 c and 11 d of the fixed tube 11, and the locking projections of the locking devices 17 and 18 are inserted into the fixed tube 11. When the projection is made to project, the locking projection penetrates the fixed tube 11, the left telescopic tube 12 and the right telescopic tube 14.

  Thereby, the left telescopic tube 12 and the right telescopic tube 14 can be fixed to the fixed tube 11. Further, since a plurality of holes are provided, the left telescopic tube 12 and the right telescopic tube 14 can be fixed to the fixed tube 11 with a plurality of relative positional relationships. In other words, it is possible to fix the left telescopic tube 12 and the right telescopic tube 14 from the fixed tube 11 with various amounts of extension.

Next, referring to FIGS. 10 to 15, the left leg 13 extending downward from the outer end that is the left end of the left telescopic tube 12, and the lower end from the outer end that is the right end of the right telescopic tube 14. A description will be given of a telescopic leg structure in which the lengths of the left leg part 13 and the right leg part 15 extending downward from the outer end part are adjustable. FIG. 10 is a diagram showing the telescopic leg structure of the left leg portion 13 as viewed from an oblique direction, and FIG. 11 is a perspective view showing the assembled state by disassembling the telescopic leg structure,
12 is a cross-sectional view of the telescopic leg structure, FIG. 13 is a cross-sectional view showing the operating state of the telescopic leg structure, FIG. 14 is a cross-sectional view showing a modification of the telescopic leg structure, and FIG. It is sectional drawing which shows the other modification. Since the left leg portion 13 and the right leg portion 15 have the same telescopic leg structure, the following description will be made taking the left leg portion 13 as an example.

  The left leg portion 13 has a receiving portion 21 as an insertion portion fixed to the outer end of the left telescopic tube 12 with the direction of the insertion hole 21 a oriented substantially in the vertical direction, and a longitudinal portion in the insertion hole 21 a of the receiving portion 21. It has a leg column 22 as a linear vertical member inserted with its direction oriented substantially in the vertical direction, and a holding mechanism 23 that holds the leg column 22 at an arbitrary insertion position in the insertion hole 21a. . The insertion hole 21 a extends in a direction substantially coincident with the longitudinal direction of the inclined portion 3 b of the left column 3.

  The pedestal 22 is a linear member having a longitudinal direction that is substantially the same as the longitudinal direction of the left column 3 and is a member made of an aluminum alloy. The pedestal 22 is coated with alumite treatment, thereby improving the slidability and confirming the wear state. The pedestal 22 inserted through the insertion hole 21a is oriented along the direction in which the insertion hole 21a extends, and the longitudinal direction of the pedestal 22 is substantially the same as the longitudinal direction of the inclined portion 3b of the left column 3. The leg column 22 is slidable in a direction substantially coincident with the longitudinal direction of the inclined portion 3b of the left column 3.

  The outer surface 22 a of the pedestal 22 has a concavo-convex engagement surface 22 b as a first concavo-convex engagement surface, and has an uneven shape in which irregularities appear regularly along the longitudinal direction of the pedestal 22. In addition, this uneven | corrugated shape may be formed by penetrating the metal which comprises the outer side surface 22a of the pedestal 22 in the front and back, and may be formed as a dent with the predetermined depth on the surface of the outer side surface 22a.

  The holding mechanism 23 is provided on the side of the insertion hole 21a facing the concave and convex engaging surface 22b of the pedestal 22. The holding mechanism 23 switches between a released state in which the pedestal 22 can freely slide in the insertion hole 21a and a restricted state in which the pedestal 22 is prevented from sliding in the insertion hole 21a. Can be realized. That is, the holding mechanism 23 is released and the pedestal 22 is slid and moved to an appropriate position, and then the holding mechanism 23 is switched to the restricted state, so that the pedestal 22 of any length can be moved more than the left telescopic tube 12. It can be made the state extended below. Thereby, the expansion-contraction length of the pedestal 22 can be adjusted suitably.

  In the present embodiment, in the holding mechanism 23, the concavo-convex engagement plate member 24 having the concavo-convex engagement surface 24a as the second concavo-convex engagement surface disposed inside the insertion hole 21a and the concavo-convex engagement surface 24a are parallel to each other. The expansion / contraction length of the pedestal 22 is adjusted by the parallel link mechanism 25 that moves the uneven engagement plate member 24 so as to move. The parallel link mechanism 25 includes a state in which the uneven engagement surface 24 a of the uneven engagement plate member 24 is in surface contact with the uneven engagement surface 22 b of the outer surface 22 a of the pedestal 22, and the uneven engagement surface of the uneven engagement plate member 24. The state where 24a is separated from the concave-convex engaging surface 22b of the outer side surface 22a of the pedestal 22 can be appropriately switched. The uneven engagement plate member 24 is a member made of an aluminum alloy. By applying electroless nickel plating, the surface hardness is increased to improve the slidability, the wear resistance is improved, and the durability and operability are improved. I'm allowed.

  In the present embodiment, a plurality of grooves 22c having a longitudinal direction in the left-right direction are formed on the uneven engagement surface 22b of the pedestal 22 at regular intervals along the longitudinal direction of the pedestal 22, and the uneven engagement plate A plurality of protrusions 24 b having a longitudinal direction in the left-right direction are formed on the uneven engagement surface 24 a of the member 24 at regular intervals along the longitudinal direction of the pedestal 22. The protrusions 24b and the groove 22c are formed at intervals corresponding to each other.

  The parallel link mechanism 25 includes joint members 26 and 27 that link the concave and convex engaging plate member 24 in parallel to the receiver 21, two fixed shafts that are pivotally supported by the receiver 21, and a joint member 26 and 27 have two movable shafts pivotally supported by the concave / convex engaging plate member 24. The relative positional relationship between the fixed shaft and the metal receiver 21 does not change, and the movable shaft moves together with the concave and convex engaging plate member 24 and the relative positional relationship with the metal receiver 21 varies.

  The joint member 26 includes a connecting portion 26a for connecting the fixed shaft and the movable shaft, a shaft hole 26b for inserting the shaft member 28 as the fixed shaft, a shaft portion 26c constituting the shaft portion 26c as the movable shaft, Have The shaft hole 26 b receives the shaft member 28 supported by the metal receiver 21 and is pivotally supported by the shaft member 28. The shaft portion 26c is loosely fitted in a joint recess 24d formed on the back surface 24c of the concave-convex engagement plate member 24, so that the shaft portion 26c can rotate in the joint recess 24d. Thereby, the metal receiver 21 and the concave-convex engagement plate member 24 are linked via the movable shaft and the fixed shaft.

  Similarly, the joint member 27 includes a connecting portion 27a for connecting the fixed shaft and the movable shaft, a shaft hole 27b for inserting the shaft member 29 as the fixed shaft, and a shaft portion constituting the shaft portion 27c as the movable shaft. 27c. The shaft hole 27 b receives the shaft member 29 supported by the metal receiver 21 and is pivotally supported by the shaft member 29. The shaft portion 27c is loosely fitted in a joint recess 24e formed on the back surface 24c of the concave-convex engagement plate member 24 so that the shaft portion 27c can rotate in the joint recess 24e. Thereby, the metal receiver 21 and the concave-convex engagement plate member 24 are linked via the movable shaft and the fixed shaft. The joint members 26 and 27 are made of aluminum alloy. By applying electroless nickel plating, the surface hardness is increased to improve the sliding property, and the wear resistance is improved, and the durability and operability are improved. I'm allowed.

  As shown in FIGS. 10 to 12, the shaft portions 26c and 27c of the joint members 26 and 27 have a round bar shape whose diameter is larger than the thickness of the connection portions 26a and 27a, and the shaft portions 26c and 27c are joint recesses 24d and 24e. When it is loosely fitted inside, the joints 24d and 24e are narrower than the diameters of the shaft portions 26c and 27c, and are extended from the connection portions 26a and 27a. The openings of the joint recesses 24d and 24e are formed narrower than the diameters of the shaft portions 26c and 27c and wider than the thicknesses of the connection portions 26a and 27a. The shaft portions 26c and 27c are loosely fitted into the joint recesses 24d and 24e by being slid into the joint recesses 24d and 24e from the side of the uneven engagement plate member 24. Screws or the like are not required for loose fitting of the shaft portions 26c and 27c to the joint recesses 24d and 24e, and the shaft member 28 pivotally supported by the shaft holes 26b and 27b needs to be fixed to the receiver 21 with screws or the like. is there. In the parallel link mechanism 25, it is necessary to provide at least four shafts. For the shafts provided close to each other, one is a screw-needed shaft and the other is a screw-unnecessary shaft. It is possible to prevent the interference of the screw head).

  A shaft hole 26b through which the shaft member 28 as the fixed shaft of the joint member 26 is inserted is positioned above the shaft portion 26c as the movable shaft, and a shaft hole through which the shaft member 29 as the fixed shaft of the joint member 27 is inserted. 27b is located above the shaft part 27c as a movable shaft. That is, in the parallelogram formed by connecting the two fixed shafts and the two movable shafts, the inner angle formed at the position of the shaft portion 26c and the shaft hole 27b is an acute angle, and the position of the shaft hole 26b and the shaft portion 27c. The interior angle formed in this is an obtuse angle. Therefore, the joint members 26 and 27 are inclined downward from the shaft holes 26b and 27b toward the shafts 26c and 27c.

  The joint member 26 has a lever portion 26d as an operation portion that extends to the opposite side of the shaft portion 26c across the shaft hole 26b. The lever portion 26d is exposed to the outside of the receiver 21 through an opening 21b provided in the receiver 21, and the inclination angle of the parallel link mechanism 25 can be adjusted by operating the lever portion 26d. It is like that. That is, when the lever part 26d is operated in the pulling direction, the concave / convex engaging plate member 24 is moved in a direction approaching the outer surface 22a of the pedestal 22, and conversely, when the lever part 26d is operated in the pushing direction, the concave / convex engaging plate member 24 is moved. The column 22 moves away from the outer surface 22a.

  The lever portion 26d is provided with a spring 32 as a spring member formed of a conical coil spring that is biased in a direction to separate the lever portion 26d and the concave-convex engagement plate member 24 from the concave-convex engagement plate member 24. It is disguised. The spring 32 is made difficult to be twisted so that the apex side of the cone faces the lever portion 26d and contacts the lever portion 26d at a point. By interposing the spring 32 between the lever portion 26d and the concave and convex engaging plate member 24, stress is applied in a direction in which the lever portion 26d and the rear surface 24c of the concave and convex engaging plate member 24 are separated. This maintains the state in which the concave and convex engaging surface 24a of the concave and convex engaging plate member 24 is engaged with the concave and convex engaging surface 22b of the outer side surface 22a of the pedestal 22 in a state where the lever portion 26d is not operated. The pedestal 22 is prevented from sliding in the insertion portion 21a in a state where the operation is not performed on 26d. The lever portion 26d is curved so that the concave portion faces the concave and convex engaging plate member 24, and one end of the spring 32 is brought into contact with the concave portion of the curved portion, so that the spring 32 is connected to the lever portion 26d and the concave and convex engaging plate member 24. Structurally held between them.

  The concave / convex engaging plate member 24 is provided with a lever portion 24f as an operation portion that is bent and extended in a direction away from the outer surface 22a at an upper end portion thereof. The lever portion 24f is exposed from the upper side of the metal receiver 21 and can be operated from the outside. When the lever portion 24f is operated so as to apply a downward stress, the shaft members 28 and 29 serving as the fixed shaft and the shaft portions 26c and 27c serving as the working shaft are used as the rotation shaft to resist the urging force of the spring 32. The engagement plate member 24 is translated in a direction away from the pedestal 22. That is, the uneven engagement plate member 24 can be separated from the outer surface 22a of the pedestal 22 also by operating the lever portion 24f.

  In the telescopic leg structure configured as described above, the weight of the ladder body 2 and the user using the ladder body 2 and the load loaded on the ladder body 2 act as stress that pushes down the left telescopic pipe 12 downward. A downward stress is applied to the metal receiver 21 fixed to the left telescopic tube 12 and the shaft members 28 and 29 as fixed shafts fixed to the metal receiver 21. On the other hand, since the lower end of the pedestal 22 is used in contact with the mounting surface of the ladder body 2, the concavo-convex engagement surface 24 a is concavo-convexly engaged with the concavo-convex engagement surface 22 b of the outer surface 22 a of the pedestal 22. An upward reaction force is applied to the uneven engagement plate member 24.

  Here, since the shaft members 28 and 29 serving as the fixed shaft and the shaft portions 26c and 27c serving as the movable shaft have a positional relationship offset in the horizontal direction, the movable shaft is centered on the fixed shaft in the counterclockwise direction in FIG. When the torque to be rotated is generated, and the weight of the ladder body 2 and the user who uses the ladder body 2 or the load loaded on the ladder body 2 is larger, the uneven engagement surface 24a of the uneven engagement plate member 24 is moved to the pedestal 22. The pressing force against the concavo-convex engagement surface 22b increases, and the concavo-convex engagement force between the concavo-convex engagement surfaces increases. That is, the force for maintaining the extension / contraction length of the column 22 in the extension / contraction leg structure is improved.

  Further, the protrusion 24b formed on the concave / convex engaging surface 24a of the concave / convex engaging plate member 24 has a stepped portion at the lower boundary in the vertical cross-sectional shape in the direction along the longitudinal direction of the pedestal 22 so that the concave / convex engaging surface 24a. On the other hand, the step at the upper boundary is a gentle edge shape with respect to the concavo-convex engagement surface 24a, with a steep edge shape substantially perpendicular to the surface. In other words, while suppressing the pedestal 22 from sliding upward relative to the receiver 21, the pedestal 22 slides downward relative to the receiver 21. It is easy to do. Thereby, when the lever portions 26d, 24f, etc. are not operated, shortening of the length of the telescopic leg extending below the left telescopic tube 12 is suppressed, and the length of the telescopic leg extending below the left telescopic tube 12 is easily extended. It is. Therefore, when the top of the pedestal 22 is pushed or the lower part of the pedestal 22 is pulled down, the pedestal 22 can be easily extended.

  In the above-described embodiment, the shaft structure of the joint members 26 and 27 is the shaft hole 26b for the shaft support structure with the receiver 21 and the shaft support structure with the concave and convex engaging plate member 24 is in the joint recesses 24d and 24e. However, the shaft support structure with the metal receiver 21 may have the same configuration as the shaft support structure with the concave-convex engagement plate member 24. FIG. 14 shows a shaft support structure according to this modification. In this case, since the lever part 26d cannot be provided structurally, the opening 21b for exposing the lever part 26d to the outside is not provided.

  The number of joint portions may be two or more. For example, the number of joint portions may be three as shown in FIG. Thus, by increasing the number of joint parts, the stress concerning the joint parts can be dispersed and the durability of the product can be improved.

(2) Second embodiment:
Next, another example of the outrigger portion 10 of the stepladder 1 will be described. 16 is a view showing the outrigger portion 10 according to the present embodiment as viewed from the front, FIG. 17 is a cross-sectional view taken along the line YY shown in FIG. 16, and FIG. 18 is a Z shown in FIG. FIG. 19 is a cross-sectional view taken along the line -Z, and FIG. 19 is a view for explaining an end tool shape provided at the lower end of the leg portion. In the present embodiment, the same or corresponding components as those in the first embodiment will be described with the same reference numerals.

  First, the outrigger structure shown in FIG. 16 includes a cross-sectional shape of the fixed tube 11, the left telescopic tube 12 and the right telescopic tube 14, a column mounting member 40 for mounting the column to the fixed tube 11, and the left leg 13 of the left telescopic tube 12. When the end tool 50 is attached to the lower end of the right leg 15 of the right telescopic tube 14, and the end tool 50 is attached to the lower end of the left leg 13 of the left telescopic tube 12 and the lower end of the right leg 15 of the right telescopic tube 14. The end tool mounting member 60 to be used is characterized.

  The column attachment member 40 includes an annular fitting portion 41 that is attached and fixed to the fixed tube 11, support base portions 42 and 43 that are formed so as to project from the annular fitting portion 41 in the front-rear direction, front and rear support base portions 42, 43 has a fixing wall 44 erected from at least one of 43 and screw insertion holes 45a to 45d through which screws are inserted. One support attachment member 40 is provided at each of the left and right ends of the fixed tube 11. The column attaching member 40 is fixed to the fixed tube 11 by inserting the fixed tube 11 into the annular fitting portion 41 and screwing or the like.

  A notch-like recess 46 is formed in the lower end portion of the support column 3 so as to be fitted into the cross-sectional shape of the fixed tube 11 from above. By fitting this recess 46 adjacent to the inside of the column attachment member 40 attached and fixed to the fixed tube 11 to the fixed tube 11, the left and right side walls 47 and 48 in the U-shaped cross-sectional shape of the column 3 are formed. It will be in the state which the lower end just contact | abutted to the upper surface of the support stand parts 42 and 43 just. In this state, fixing screws are inserted into the screw insertion holes 45a to 45d and fixed to the screw holes 49a to 49d of the support column 3 by screws. Thereby, the support column 3 is fixed to the fixed tube 11.

  In the present embodiment, the fixed tube 11 has a cross-sectional shape with respect to the longitudinal direction, and has an upper surface 11e and a lower surface 11f having a mountain-shaped bulging shape with the center as a protruding end, and has a substantially hexagonal cross-sectional shape as a whole. As a result, the fixed tube 11 has two types of surfaces with different inclination angles on the upper surface 11e, and the front half of the upper surface 11e of the fixed tube 11 becomes an inclined surface inclined downward on the front side, and the upper surface 11e of the fixed tube 11 The rear half is an inclined surface inclined downward on the rear side. As a result, when the ladder body 2 is installed at an angle, at least one of the front and rear surfaces of the upper surface 11e of the fixed pipe 11 is relatively horizontal, which is convenient when the fixed pipe 11 is used as a ladder for the ladder body 2. improves.

  The left telescopic tube 12 and the right telescopic tube 14 are provided with a guide structure for guiding the sliding direction of the left telescopic tube 12 within the right telescopic tube 14. This guide structure has a groove 141 as a guide groove extending in a direction along the expansion / contraction direction, which is the longitudinal direction of the pipe, on the inner side surface of the right expansion / contraction pipe 14, and the outside of the left expansion / contraction pipe 12. It is comprised by the protrusion 121 as a guide protrusion extended in the direction along the expansion-contraction direction which is a longitudinal direction of a pipe | tube in the side surface. The groove 141 is formed at the upper and lower ends of the left and right side surfaces in the cross-sectional shape with respect to the longitudinal direction of the right telescopic tube 14, and the protrusion 121 is the upper and lower ends of the left and right side surfaces in the cross-sectional shape with respect to the longitudinal direction of the left telescopic tube 12. It is formed in each part.

  For this reason, when the right telescopic tube 14 and the left telescopic tube 12 are nested in the fixed tube 11, the protrusion 121 of the left telescopic tube 12 is fitted into the groove 141 of the right telescopic tube 14 and the right A guide structure for guiding the sliding movement of the left telescopic tube 12 with respect to the telescopic tube 14 is realized.

  The end tool 50 is attached to the lower end portion of the pedestal 22 and serves as an anti-slip member between the ladder body 2 and the installation surface. In the end tool 50, the angle between the anti-slip surface 51 and the pedestal 22 is set to the inclination angle of the ladder body 2 so that the anti-slip surface 51 of the end tool 50 maintains the facing state with the installation surface of the ladder body 2. It has a structure that changes accordingly. The end tool 50 is pivotally supported by a flat anti-slip member 52 having a non-slip surface 51 on the lower surface, a pivot member 53 fixed to the upper surface of the non-slip member 52, and the pivot member 53. It has a first rotating shaft 54 and a second rotating shaft 55 as two rotating shafts. The anti-slip surface 51 of the anti-slip member 52 may be formed of a material having a high coefficient of friction such as rubber or resin, or may be provided with a non-slip uneven structure.

  The shaft support member 53 has a pair of shaft support portions (a left standing wall 53a and a right standing wall 53b) standing on the upper surface thereof. The first left shaft hole 53a1 of the left standing wall 53a and the first right shaft hole of the right standing wall 53b. 53b1 (not shown) supports the first rotation shaft 54, and the second left shaft hole 53a2 of the left standing wall 53a and the second right shaft hole 53b2 (not shown) of the right standing wall 53b are second. A rotating shaft 55 is pivotally supported. In this axially supported state, the first rotating shaft 54 and the second rotating shaft 55 are in a positional relationship that is offset from each other in the front-rear direction.

  The end tool attaching member 60 is a member used to fix the end tool 50 to the lower end portion of the pedestal 22, a curved long hole 61 for inserting the first rotating shaft 54, and the second rotating shaft 55. A curved elongated hole 62 for inserting the curved elongated hole 62, a fulcrum 63 provided in an inverted V shape between the curved elongated hole 61 and the curved elongated hole 62, and a lower end portion of the pedestal 22 with screws. A fixing portion 64 is provided.

  The curved long hole 61 and the curved long hole 62 are provided in a positional relationship in which curved concave portions are opposed to each other. For example, each of the curved long hole 61 and the curved long hole 62 is provided so as to form a part of the same virtual arc in the cross-sectional shape with respect to the extending direction of the long hole, with respect to the virtual center of the virtual circle. The curved long holes 61 and 62 are provided in a positional relationship that is point-symmetric.

  Further, the V-shaped tip 65 of the fulcrum 63 is provided at a position and shape corresponding to the virtual arc of the virtual circle described above, and is approximately between the curved long hole 61 and the curved long hole 62 in the virtual arc described above. Is located. As a result, when the first rotating shaft 54 is inserted into the curved long hole 61 and the second rotating shaft 55 is inserted into the curved long hole 62 and supported by the shaft support member, the distal end portion 65 of the end tool 50 The first rotating shaft 54 inserted into the curved long hole 61 and the second rotating shaft 55 inserted into the curved long hole 62 can swing with the top surface 65 as a fulcrum.

  The curved long hole 61 is provided in a higher positional relationship than the curved long hole 62, and the curved long hole 61 and the curved long hole 62 are angled from the direction along the longitudinal direction of the pedestal 22 toward the curved long hole 62. They are provided symmetrically about an imaginary axis inclined by θ. For this reason, when the ladder body 2 is tilted forward by an angle θ so that the longitudinal direction of the ladder body 2 and the virtual axis line are substantially parallel, the curved long hole 61 and the curved long hole 62 are bidirectional. The axis is symmetrical with respect to the axis, and the swingable range of the end tool 50 with respect to the inclination of the mounting surface of the ladder body 2 is ensured substantially equally in both the front and rear.

(3) Third embodiment:
FIG. 20 is a diagram for explaining the leg portions (the left leg portion 13 and the right leg portion 15) of the stepladder 1 according to the present embodiment. In the present embodiment, the same or corresponding components as those in the first embodiment or the second embodiment described above are denoted by the same reference numerals, and detailed description thereof is omitted. Moreover, since the left leg part 13 and the right leg part 15 are symmetrical structures, the left leg part 13 is illustrated in FIG.

  The left leg portion 13 shown in FIG. 20 has a telescopic leg structure that expands and contracts up and down by a screw structure, and the left telescopic tube 12 is oriented with the cylinder axis oriented in a substantially vertical direction substantially parallel to the column 3. An upper cylindrical portion 302 as a linear outer cylindrical portion fixed to the outer end portion of the upper cylindrical portion 302, a lower cylindrical portion 301 as an inner cylindrical portion that is inserted into the cylindrical portion of the upper cylindrical portion 302 so as to be freely detachable from below, A shaft member 303 as a multi-thread screw inserted into the cylindrical portion 302 and a knob portion 304 as a rotation operation portion fixed to the upper end portion of the shaft member 303 are configured. The upper cylindrical portion 302 is configured integrally with the left telescopic tube 12 by fixing a portion from the lower part of the side surface to the outer end portion of the left telescopic tube 12.

  The shaft member 303 is fixed to the upper end portion of the upper cylindrical portion 302 so as to be rotatable about the shaft, and a knob portion for screw-rotating the shaft member 303 at a portion protruding upward from the upper end portion of the upper cylindrical portion 302. 304 is provided. The shaft member 303 extends in the cylinder of the upper cylinder portion 302 to the upper end portion of the lower cylinder portion 301, and has a multi-threaded screw structure in which the side surface of the shaft member 303 is threaded.

  A female screw portion 305 that is screwed into the multi-threaded screw of the shaft member 303 is provided on the upper portion of the lower cylinder portion 301, and the multi-threaded screw structure of the shaft member 303 is screwed into the female screw portion 305. For this reason, when the knob portion 304 is rotated and the shaft member 303 is rotated about the axis, the shaft member 303 screwed into the female screw portion 305 of the lower cylinder portion 301 is moved upward or downward according to the rotation direction. Ascending in the direction. In conjunction with the vertical movement of the shaft member 303, the upper tube portion 302 fixed to the shaft member 303 and the left telescopic tube 12 fixed to the upper tube portion 302 also slide up and down. Thus, according to the structure concerning this embodiment, the left leg part 13 can be expanded-contracted up and down with a screw structure.

  A non-slip end tool 306 is attached to the lower end of the lower cylinder portion 301. As this non-slip end tool 306, a uniaxial non-slip end tool is adopted. The anti-slip end tool 306 is a member in which the angle between the anti-slip surface 307 and the left leg 13 changes according to the inclination angle of the ladder body 2. Of course, you may employ | adopt the cap-shaped end tool concerning 1st Embodiment mentioned above, and the end tool 50 concerning 2nd Embodiment.

  The anti-slip end tool 306 is pivotally supported by the anti-slip member 308 on the flat plate having the anti-slip surface 307 on the lower surface, the shaft support member 309 fixed to the upper surface of the anti-slip member 308, and the shaft support member 309. One rotating shaft 310 is provided. The anti-slip surface 307 of the anti-slip member 308 may be formed of a material having a high coefficient of friction such as rubber or resin, or may be provided with a non-slip uneven structure.

  The shaft support member 309 is provided with a pair of left and right shaft support portions 311 (a left standing wall and a right standing wall (the right standing wall is not shown)) standing on the upper surface thereof, and the left shaft hole 312 of the left standing wall and the right axis of the right standing wall. A rotary shaft 310 is pivotally supported between the holes. The left shaft hole 312 and the right shaft hole are in the shape of a long hole that is long in the vertical direction, and the rotary shaft 310 is movable up and down in the long hole.

  A lower end portion of the lower cylinder portion 301 is formed obliquely in a direction substantially perpendicular to the expansion / contraction direction of the left telescopic tube 12. That is, the lower end portion of the lower cylinder portion 301 is such that the front end portion of the ladder body 2 is longer than the back end portion. For this reason, when the rotation shaft 310 is located at the upper end of the left shaft hole 312 and the long hole of the right shaft hole, only the front side end portion of the ladder body 2 at the lower end portion of the lower cylinder portion 301 is the anti-slip member 308. When the rotating shaft 310 is positioned at the lower end of the left shaft hole 312 and the long hole of the right shaft hole, the entire lower end portion of the lower cylinder portion 301 is substantially in contact with the upper surface of the anti-slip member 308. Therefore, in a state where the ladder body 2 is tilted forward by a predetermined angle, the entire lower end portion of the lower cylinder portion 301 is substantially in contact with the upper surface of the anti-slip member 308, and the lower end of the ladder body 2 is stabilized.

(4) Fourth embodiment:
FIG. 21 is a diagram illustrating the outrigger portion 10 of the stepladder 1 according to the present embodiment. In the present embodiment, the same or corresponding components in the first embodiment or the second embodiment described above are denoted by the same reference numerals, and detailed description thereof is omitted. Further, the left telescopic tube 12 and the member attached thereto, and the right telescopic tube 14 and the member attached thereto are symmetrically configured, so FIG. 21 illustrates the left telescopic tube 12 and the members attached thereto. It is.

  The left telescopic tube 12 shown in FIG. 21 is not provided with the left leg 13, and the end tool 50 according to the second embodiment with respect to the end of the left telescopic tube 12 is the same as the end tool mounting member 60. It is mounted and fixed directly via the end tool mounting member 160. That is, the ladder body 2 according to the present embodiment has the outrigger portion 10 whose base width can be expanded and contracted by the left and right telescopic tubes, but the length of the leg portion extending downward from the distal end of the telescopic tube is adjusted. It is the structure which does not have the structure of the expansion-contraction leg to do.

  The end tool mounting member 160 according to the present embodiment has substantially the same shape and configuration as the end tool mounting member 60 according to the second embodiment, but is screwed to the lower end portion of the pedestal 22. The shape of the fixing portion 64 for this purpose is modified in accordance with the structure of the left telescopic tube 12.

  That is, the fixing portion 164 of the end fitting attaching member 160 is constituted by a front standing wall 165 and a rear standing wall 166 that are erected along the front surface 12c and the rear surface 12d of the left telescopic tube 12, and the front wall 165 and the rear wall 166 are connected to each other. It is attached and fixed integrally to the right telescopic tube 14 by being fixed to the front surface 12c and the rear surface 12d by screws or the like, respectively, but left and right at the lower right corner and the lower left corner on the outer side of the cross section of the left telescopic tube 12 Since the ridges 12e and 12f have a bulging shape and extend in a direction along the direction of expansion and contraction of the right telescopic tube 14, the front standing wall 165 and the rear standing wall 166 are on the side facing the front surface 12c and the rear surface 12d. Recesses 167 and 168 along the bulging shape of the protrusions 12e and 12f are provided.

  Since the front wall 165 and the rear wall 166 are fixed to the front surface 12c and the rear surface 12d while the recesses 167 and 168 are engaged with the protrusions 12e and 12f, the fixing strength of the end member mounting member 160 to the right telescopic tube 14 is improved. can do.

(5) Fifth embodiment:
FIG. 22 is a view for explaining the fixed tube 11 of the stepladder 1 and the column attaching member 40 attached to the stepladder 1 according to the present embodiment. In the present embodiment, the same or corresponding components in the first embodiment or the second embodiment described above are denoted by the same reference numerals, and detailed description thereof is omitted.

  The fixed tube 11 shown in FIG. 22 has a structure similar to that of the column mounting member 40 according to the second embodiment at the end of the fixed tube 11, but has a curved long hole similar to the end tool mounting member 60 at the lower part thereof. A column attachment member 540 provided with a 561, a curved long hole 562, and a fulcrum 563 is attached and fixed.

  In other words, in the present embodiment, the first rotation shaft 54 inserted through the curved elongated hole 561 and the second rotation inserted through the curved elongated hole 562 at the lower end of the telescopic leg of the outrigger portion 10 which can be expanded and contracted in the left-right width. An end tool 50 that swings in two axes with the shaft 55 is provided, and an end tool similar to the end tool 50 according to the second embodiment can be attached to the lower part of the left and right ends of the fixed tube 11. Yes.

  Thereby, when the outrigger part 10 which expands and contracts to the left and right is unnecessary, the left and right telescopic pipes 12 and 14 are removed from the fixed pipe 11 and at the lower ends of the left and right ends of the fixed pipe 11, By attaching the tool, it is possible to realize a biaxially oscillating rotary shaft configuration similar to that of the second embodiment at the lower ends of the pair of columns 3.

  Note that the present invention is not limited to the above-described embodiments, and the configurations disclosed in the above-described embodiments are interchanged with each other or the combinations thereof are changed, disclosed in the known technology, and in the above-described embodiments. A configuration in which each configuration is mutually replaced or a combination is changed is also included. Further, the technical scope of the present invention is not limited to the above-described embodiments, but extends to the matters described in the claims and equivalents thereof.

DESCRIPTION OF SYMBOLS 1 ... Stepladder, 2 ... Ladder body, 3 ... Support | pillar, 3a ... Vertical part, 3b ... Inclined part, 3c ... Side wall part, 3d ... End wall part, 4 ... Footpiece, 6 ... Joint metal fitting, 6a ... Fixed part, 6b DESCRIPTION OF SYMBOLS ... Hinge part, 8 ... Stop fitting, 10 ... Outrigger part, 11 ... Fixed pipe, 11a ... Left opening, 11b ... Right opening, 11c ... Hole, 11d ... Hole, 12 ... Left telescopic pipe, 12a ... Hole, 12b ... Hole, 12c ... End tool, 12c ... Front face, 12d ... Rear face, 12e ... Projection, 12f ... Projection, 13 ... Left leg, 14 ... Right telescopic tube, 14a ... Hole, 14b ... Hole, 15 ... Right leg , 16 ... connecting member, 17 ... locking device, 18 ... locking device, 21 ... receiving device, 21a ... insertion hole, 21b ... opening, 22 ... pedestal, 22a ... outer surface, 22b ... uneven engagement surface, 22c ... strip Groove, 23 ... holding mechanism, 24 ... uneven engagement plate member, 24a ... uneven engagement surface, 24b ... protrusion, 24c ... Surface, 24d ... Joint recess, 24e ... Joint recess, 24f ... Lever part, 25 ... Parallel link mechanism, 26 ... Joint member, 26a ... Connection part, 26b ... Shaft hole, 26c ... Shaft part, 26d ... Lever part, 27 ... Joint member, 27a ... connection portion, 27b ... shaft hole, 27c ... shaft portion, 28 ... shaft member, 29 ... shaft member, 32 ... spring, 40 ... post attaching member, 41 ... annular fitting portion, 42, 43 ... support Base part 44 ... Fixing wall part 45a-45d ... Screw insertion hole part 46 ... Recessed part 47, 48 ... Left and right side walls 49a-49d ... Screw hole 50 ... End tool 51 ... Anti-slip surface 52 ... Non-slip member, 53 ... shaft support member, 53a ... left standing wall, 53b ... right standing wall, 53a1 ... first left shaft hole, 53a2 ... second left shaft hole, 53b1 ... first right shaft hole, 53b2 ... second right shaft Hole 54 ... first rotation axis 55 ... second Rotating shaft, 60 ... end fitting mounting member, 61 ... curved long hole, 62 ... curved long hole, 63 ... fulcrum part, 64 ... fixing part, 65 ... tip part, 121 ... ridge, 141 ... groove, 160 ... end Tool mounting member, 164 ... fixed portion, 165 ... front wall, 166 ... rear wall, 301 ... lower tube portion, 302 ... upper tube portion, 303 ... shaft member, 304 ... knob portion, 305 ... female screw portion, 306 ... slip Stop end tool, 307 ... Anti-slip surface, 308 ... Anti-slip member, 309 ... Axle support member, 310 ... Rotating shaft, 311 ... Axle support part, 312 ... Left shaft hole, 540 ... Column support member, 561 ... Curve long hole, 562 ... curved long hole, 563 ... fulcrum

Claims (12)

A tubular fixed tube that is fixed in a horizontal orientation between a pair of left and right columns of the ladder body; and
A tubular first telescopic tube accommodated in the tube from one opening of the fixed tube and telescopic from the one opening;
A second telescopic tube that is accommodated in the tube from the other opening of the fixed tube and is extendable from the other opening, and
The first telescopic tube and the second telescopic tube can be accommodated in the fixed tube with at least a part of the first telescopic tube and the second telescopic tube overlapping each other. A stepladder. The state in which at least a part of the first telescopic tube and the second telescopic tube overlaps with each other in the fixed tube is such that the second telescopic tube accommodates at least a part of the first telescopic tube inside. It is an aspect to
The outer shape of the first telescopic tube substantially matches the inner shape of the second telescopic tube;
2. The stepladder according to claim 1, wherein the inner end portion of the first telescopic tube on the fixed tube side has a structure in which the diameter decreases as the outer shape approaches the inner end. The state in which at least a part of the first telescopic tube and the second telescopic tube overlaps with each other in the fixed tube is such that the second telescopic tube accommodates at least a part of the first telescopic tube inside. It is an aspect to
The outer shape of the first telescopic tube substantially matches the inner shape of the second telescopic tube;
The inner shape of at least a part of the fixed tube near the one opening is reduced in diameter as compared with the inner shape of the fixed tube near the other opening. The stepladder described. A guide groove is provided along the direction of expansion and contraction of the inner surface of the second expansion tube,
4. The stepladder according to claim 2, wherein a guide protrusion is provided that engages with the guide groove along the extending and contracting direction of the outer surface of the first expansion tube. The outer ends of the first telescopic tube and the second telescopic tube opposite to the fixed tube are respectively provided with telescopic legs capable of adjusting the length of the legs extending downward from the outer end. The stepladder according to any one of claims 1 to 4, wherein the stepladder is provided. The telescopic legs have an outer cylinder portion that is fixed to the outer end portion with a cylindrical axis oriented substantially in the vertical direction, an inner cylinder portion that is inserted into the cylinder of the outer cylinder portion so as to be freely removable from below, A multi-threaded screw inserted into the outer cylinder, and a rotation operation unit fixed to the upper end of the multi-threaded screw;
A female screw portion that is screwed into the multi-thread screw is provided on the upper portion of the inner cylinder portion, and the multi-thread screw is fixed to the outer cylinder portion so as to be axially rotatable. 6. The stepladder according to claim 5, wherein the outer cylinder portion slides relative to the inner cylinder portion by axial rotation of the multi-thread screw accompanying the rotation operation. The telescopic leg has a linear shape in which the direction of the insertion hole is oriented in a substantially vertical direction and is inserted in the insertion hole provided in the outer end, and the longitudinal direction is oriented in the vertical direction in the insertion hole. A vertical member, a plate member disposed inside the insertion hole, and an operation unit for adjusting a distance between the vertical member and the plate member,
A first concavo-convex engagement surface is formed along the longitudinal direction on the side surface of the vertical member,
A second concavo-convex engagement surface is formed on the plate member on the side facing the vertical member,
When the first concavo-convex engagement surface and the second concavo-convex engagement surface abut, the sliding movement of the vertical member in the insertion portion is restricted, and the first concavo-convex engagement surface and the second concavo-convex engagement surface are 6. The stepladder according to claim 5, wherein the regulation of the sliding movement of the vertical member in the insertion portion is released when separated. The plate member has a plurality of joint members oriented downwardly inclined from the inner wall of the insertion hole toward the plate member, and is opposite to the inner surface of the insertion portion and the second uneven engagement surface of the plate member. The stepladder according to claim 7, wherein the stepladder is connected to an inner wall of the insertion portion by a parallel link mechanism configured to connect the back surface. The stepladder according to claim 7 or 8, wherein the plate member is biased by a spring member in a direction in which the first uneven engagement surface and the second uneven engagement surface are brought closer to each other. . The operation portion is formed to extend from a shaft portion on the inner wall side of the insertion portion of the joint member,
The said spring member is interposed between the said operation part and the said plate member, and is urging | biasing by this in the direction which separates the said operation part and the back surface of the said plate member. Item 11. The stepladder according to item 9. A tubular fixed tube that is fixed in a horizontal orientation between a pair of left and right columns of the ladder body; and
A tubular first telescopic tube accommodated in the tube from one opening of the fixed tube and telescopic from the one opening;
A second telescopic tube that is accommodated in the tube from the other opening of the fixed tube and is extendable from the other opening, and
The first telescopic tube and the second telescopic tube can be accommodated in the fixed tube with at least a part of the first telescopic tube and the second telescopic tube overlapping each other. Ladder body widening structure. A step of fixing the tubular fixed tube by being oriented left and right between the pair of left and right columns of the ladder; and
Storing the tubular first telescopic tube into the tube from one opening of the fixed tube, and extending and contracting from the one opening;
A tubular second telescopic tube is housed in the tube from the other opening of the fixed tube, and is retractably accommodated from the other opening.
The first telescopic tube and the second telescopic tube can be accommodated in the fixed tube with at least a part of the first telescopic tube and the second telescopic tube overlapping each other. A method for manufacturing the ladder body.

Images