JP2016033304A - Rung fixing structure, stepladder provided with the same, and manufacturing method for rung fixing structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a simple structure for fixing a rung securely on a support post and enhance productivity, when at least a part of the support post is inclined to a direction orthogonal to an axial direction of the rung.SOLUTION: A rung fixing structure is for fixing ends of a rung 4 to a pair of support posts 3, the rung being spanned between the pair of support posts 3. The support post 3 includes an inclined part 3b that inclines with regard to a direction orthogonal to an axial direction of the rung 4, and the inclined part 3b includes a perpendicular surface part 31 that forms, on both inner and outer surfaces of the support post 3, support surfaces (31x, 31y) orthogonal to the axial direction of the rung 4 when the rung 4 is spanned between the pair of support posts 3 with both ends of the rung 4 fixed on the support posts. The rung 4 includes a body part 14 that forms a first sandwiching surface 21 coming into contact with the inner support surface 31x as an edge surface on both ends in the axial direction, and a flange part 15 that forms a second sandwiching surface 22 opposite the first sandwiching surface 21 and coming into contact with the outer support surface 31y, and is pressed against and sandwiches the perpendicular surface part 31 along with the body part 14.SELECTED DRAWING: Figure 12

Description

  TECHNICAL FIELD The present invention relates to a fixing structure for a step rail that is horizontally mounted between a pair of columns that are vertical members in a stepladder, a ladder, and the like, and a stepladder including the structure and a method for manufacturing the fixing structure for the step rail.

  In general, a stepladder, a ladder, a workbench, or the like includes a pair of columns that are vertical members and a plurality of step bars that are horizontally mounted between the pair of columns. In such a configuration, a structure using a fixing member such as a rivet, a bolt, or a screw, or welding / adhesion is used as a fixing structure of a step rail that is horizontally mounted between a pair of support columns with both ends fixed to the support columns. There are structures used. However, according to these fixed structures, there are problems such as an increase in the number of parts and production problems such as an increase in the number of steps in the manufacturing process.

  Therefore, as a fixing structure for the support of the step pedestal, conventionally, a cylindrical member is used as a member constituting the step pedestal (hereinafter referred to as “step pedestal member”), and at each of the end portions on both sides of the step pedestal member, There is a mode in which a side wall portion of a column is crimped by a pair of hook-shaped portions formed by press molding or the like (see, for example, Patent Document 1 and Patent Document 2). Such a fixing structure of the crosspiece is manufactured as follows, for example.

  In the vicinity of the end portions on both sides of the step member, an inner hook-shaped portion that comes into contact with the side wall portion of the column from the inner side in the left-right direction is formed in advance, and a portion outside the left and right hook-shaped portions in the step beam member is It inserts from the inner side of the left-right direction into the insertion hole formed in the side wall part of the left-right support | pillar. Then, the treadle member is deformed by a pressing force directed inward in the axial direction from both end sides protruding from the side wall portion of the support column in a state where it is fixedly supported by a predetermined mold or the like. An outer flange-like portion that comes into contact with the sidewall from the outside in the left-right direction is formed, and the sidewall portions of the support column are caulked by the inner and outer flange-like portions, and are pressed and sandwiched.

  In this way, according to the fixing structure of the traverse by forming a hook-like portion at the end of the traverse, compared to the structure using the fixing member as described above, the structure using welding / adhesion, etc. The number of points can be reduced and productivity can be improved.

JP-A-60-109486 Japanese Utility Model Publication No. 52-147537

  By the way, on a stepladder, ladder, work table, etc., the pair of struts are not parallel to each other for the purpose of improving the stability by increasing the distance between the ground contact positions by the pair of struts on which the traversers are horizontally mounted. Some have a structure in which the interval between the pair of support columns is partially or entirely gradually widened from the upper side to the lower side. In such a structure, when the extending direction of the support column when the pair of support columns are arranged in parallel to each other is a vertical direction, a part or all of the support column gradually spreads outward from the upper side to the lower side, It becomes the aspect arrange | positioned in the inclined form with a predetermined angle with respect to the perpendicular direction.

  In such a configuration having struts partially or wholly inclined, a structure for fixing a tram such as that described above by forming a hook-like portion at the end of the tram is applied. It becomes difficult. This is due to the fact that the side wall portion of the column sandwiched by the saddle-shaped portion of the step rail is not a surface portion perpendicular to the axial direction (cylinder axis direction) of the step rail member but an inclined surface portion. In other words, since it is relatively difficult to form the bowl-shaped portion so as to be inclined with respect to the axial direction of the step rail in accordance with the side wall portion of the inclined support column, in a configuration having a downwardly extending support column, It becomes difficult to apply the fixing structure using the hook-shaped portion of the crosspiece.

  Therefore, the end surfaces on both sides of the step member contacting the side wall of the column from the inner side in the left-right direction are inclined with respect to the axial direction of the step member in accordance with the inclination of the side wall of the column. It is possible to process. However, the process of making the end surface of the crosspiece member an inclined surface increases the number of steps in the manufacturing process and causes a decrease in productivity. Specifically, for example, the crosspiece member is an extruded product such as aluminum, and the process of cutting the crosspiece member obliquely with respect to the axial extrusion direction is cut perpendicular to the extrusion direction. This is troublesome compared to the processing to be performed, and the processing to cut obliquely causes a loss of material.

  As described above, in the configuration including a pair of struts extending downward, there is room for improvement in terms of improving productivity with respect to the fixing structure of the tram.

  The present invention has been made in view of the above-described problems of the prior art, and has a simple structure in a configuration in which at least a part of the support column is inclined with respect to a direction perpendicular to the axial direction of the step rail. Therefore, it is possible to securely fix the step rail to the support column, and to provide a step rail fixing structure capable of improving productivity, a stepladder including the same, and a method of manufacturing the step rail fixing structure. Objective.

  The fixing structure of the traversing rail according to the present invention includes a pair of struts that are vertical members, and a traversing rail that is horizontally mounted between the pair of struts, and the end of the traversing rail is fixed to the strut. The strut has an inclined portion inclined at least partially with respect to a direction perpendicular to the axial direction of the step rail, and the end of the step rail is fixed to the inclined portion. A vertical portion that forms support surfaces perpendicular to the axial direction of the step rail in a state of being laid between the pair of columns on both the inner and outer sides of the column, A main body forming a first clamping surface that contacts the inner support surface of the support surfaces as end surfaces on both sides in the axial direction, and contacts the outer support surface of the support surface while facing the first clamping surface Forming a second clamping surface, and having a clamping part that press-clamps the vertical part together with the main body part Than is.

  Further, in the fixing structure of the crosspiece according to one aspect of the present invention, the holding portion has an insertion hole in which a cylindrical protruding portion that is a portion protruding in a cylindrical shape from the first holding surface is formed in the vertical portion. It is a bowl-shaped part formed by being deformed in a penetrating state.

  Further, in the fixing structure of the step rail according to one aspect of the present invention, the step rail has an annular shape in a cross-sectional shape, and forms a cylindrical projecting portion by both end portions in the axial direction. And a tread surface forming portion that is provided outside the cylindrical core portion and forms a flat tread surface.

  Further, in the fixing structure of the step rail according to one aspect of the present invention, the cylindrical projecting portion is configured to expose the cylindrical core portion by removing portions of the step surface forming portion at both ends of the step rail. Is formed.

  Further, in the fixing structure of the crosspiece according to one aspect of the present invention, the tread surface forming portion is a hollow portion having a cross-sectional shape and an outer shape along a substantially triangular shape, and a side portion on one side in the cross-sectional shape. Thus, the tread is formed.

  Further, in the fixing structure of the step rail according to one aspect of the present invention, the cylindrical projecting portion and the insertion hole have an insertion shape that restricts relative rotation of the step rail with respect to the column in the axial direction. Is.

  The stepladder according to the present invention is provided with the fixing structure of the step rail.

  The manufacturing method of the fixing structure of the foot cross according to the present invention includes a pair of support pillars that are vertical members, and a foot support that is horizontally mounted between the pair of support pillars, and an end portion of the foot support is fixed to the support pillar. A method for manufacturing a structure for fixing a traverse, wherein at least a part has an inclined portion that is inclined with respect to a direction perpendicular to an axial direction of the traverse, and the end of the traverse is provided on the inclined portion As a portion to which the rail is fixed, there are provided vertical portions that have support surfaces that are perpendicular to the axial direction of the step rail in a state of being laid between the pair of columns on both the inner and outer sides of the column and that have insertion holes. And a main body portion forming a first clamping surface that contacts an inner supporting surface of the supporting surfaces as end surfaces on both sides in the axial direction, and a cylindrical projection from the first clamping surface A cylindrical projecting portion, which is a part that is formed, and is fixed between the pair of struts to A step of preparing a crosspiece member to be formed; a step of causing the cylindrical protruding portion to penetrate the insertion hole; and causing the cylindrical protruding portion to protrude outward in the axial direction from the vertical portion; and the first clamping surface With the pressing mold having a pressing surface in contact with the end surface of the cylindrical protruding portion in a state where the cylindrical protruding portion is in contact with the inner support surface, the cylindrical protruding portion is opposed to the protruding direction from the first clamping surface. By pressing in the direction, the sandwiching portion that forms the second sandwiching surface that faces the first sandwiching surface and contacts the outer support surface among the support surfaces is bent, and the sandwiching portion and the main body portion And the step of pressing and clamping the vertical portion.

  Further, in the method for manufacturing the fixing structure of the crosspiece according to one aspect of the present invention, the step of preparing the crosspiece member includes a hollow cylindrical core portion having an annular shape in a cross-sectional shape, and the cylindrical core portion. And a step of preparing a linear molded part having a tread surface forming part that forms a flat tread surface, and removing the tread surface forming part at both ends of the molded part. And exposing the core part to form the cylindrical projecting part.

  According to the present invention, in a configuration in which at least a part of the column is inclined with respect to a direction perpendicular to the axial direction of the step rail, the step rail can be reliably fixed to the column with a simple structure. , Productivity can be improved.

It is a perspective view which shows the stepladder which concerns on one Embodiment of this invention. It is a front view which shows the stepladder which concerns on one Embodiment of this invention. It is a perspective view showing one mode of a stepladder concerning one embodiment of the present invention. It is a perspective view which shows the fixing structure of the crosspiece which concerns on one Embodiment of this invention. It is a partial cross section perspective view which shows the fixing structure of the crosspiece which concerns on one Embodiment of this invention. It is a side view which shows the fixing structure of the crosspiece which concerns on one Embodiment of this invention. It is front sectional drawing which shows the fixing structure of the crosspiece which concerns on one Embodiment of this invention. It is side surface sectional drawing which shows the fixing structure of the crosspiece which concerns on one Embodiment of this invention. It is a perspective view which shows the crosspiece member which concerns on one Embodiment of this invention. It is explanatory drawing about the crosspiece which concerns on one Embodiment of this invention. It is a perspective view which shows the fixing structure of the crosspiece which concerns on one Embodiment of this invention. It is a partial cross section perspective view which shows the fixing structure of the crosspiece which concerns on one Embodiment of this invention. It is a side view which shows the fixing structure of the crosspiece which concerns on one Embodiment of this invention. It is front sectional drawing which shows the fixing structure of the crosspiece which concerns on one Embodiment of this invention. It is side surface sectional drawing which shows the fixing structure of the crosspiece which concerns on one Embodiment of this invention. It is explanatory drawing about the manufacturing method of the fixing structure of the foot cross which concerns on one Embodiment of this invention. It is explanatory drawing about the manufacturing method of the fixing structure of the foot cross which concerns on one Embodiment of this invention. It is explanatory drawing about the manufacturing method of the fixing structure of the foot cross which concerns on one Embodiment of this invention. It is explanatory drawing about the manufacturing method of the fixing structure of the foot cross which concerns on one Embodiment of this invention. It is explanatory drawing about the manufacturing method of the fixing structure of the foot cross which concerns on one Embodiment of this invention. It is explanatory drawing about the other structural example of the foot cross which concerns on one Embodiment of this invention. It is a side view which shows the other structural example of the fixing structure of the crosspiece which concerns on one Embodiment of this invention. It is side surface sectional drawing which shows the other structural example of the fixing structure of the foot cross which concerns on one Embodiment of this invention. It is front sectional drawing which shows the fixing structure of the crosspiece which concerns on another embodiment of this invention. It is a front view which shows the fixing structure of the crosspiece which concerns on another embodiment of this invention.

  The present invention provides a structure in which the distance between a pair of struts on which a traverse is horizontally mounted is changed in the same distance gradually, for example, in a configuration in which the distance gradually changes like a configuration in which the distance gradually increases from the upper side to the lower side. The present invention intends to simplify the structure and improve the productivity by devising the shape and the like of the fixed portion and the both end portions fixed to the support column of the step rail. Embodiments of the present invention will be described below.

  In the following, an embodiment of a fixing structure for a foot cross and a method for manufacturing the same according to the present invention will be described with reference to a ladder stepladder as an example. However, the structure for fixing the crossing and the manufacturing method thereof according to the present invention are not limited to the ladder-ladder stepladder, and for example, a pair of left and right columns such as a stepladder (dedicated stepladder), a ladder, a workbench, etc. The present invention can be applied to various lifting and lowering equipment having a ladder including a ladder that is installed between the columns.

[Configuration of stepladder]
First, the structure of the stepladder 1 which concerns on this embodiment is demonstrated using FIGS. 1-3. As shown in FIGS. 1 to 3, a stepladder 1 according to the present embodiment is a ladder-supporting stepladder also used as a ladder, and includes a pair of ladder bodies 2 having a common configuration. 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 tram 4 is horizontally mounted (a horizontal direction in FIG. 2) 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 provided below the vertical portion 3a in parallel with each other in relation to the other column 3 and below the vertical portion 3a. The column 3 extends in the direction perpendicular to the axial direction of the traversing rail 4, that is, the vertical portion 3a extends. It consists of the inclined part 3b which is a part inclined with respect to the direction. The inclined portion 3b gradually changes the distance between the pair of support columns 3 depending on the position of the ladder assembly 2 in the vertical direction in relation to the other support column 3 in the ladder assembly 2. In the stepladder 1, when the stepladder 1 is used as a stepladder, the inclined portions 3b of the pair of struts 3 have a downwardly expanding shape that gradually increases the distance between the pair of struts 3 from the upper side to the lower side.

  In this embodiment, in the column 3, the upper 1/3 to 1/4 portion constituting the upper portion of the ladder body 2 is the vertical portion 3a, and the remaining lower portion is the inclined portion 3b. (See FIG. 2). The inclined portion 3b is inclined at a predetermined angle α so as to spread outward with respect to the vertical direction when the extending direction of the vertical portion 3a (vertical direction in FIG. 2) is the vertical direction (see straight line L1 in FIG. 2). The form arranged in the shape. 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. (See FIG. 2). In the description of this embodiment, the extending direction (vertical direction in FIG. 2) of the vertical portion 3a of the column 3 is the vertical direction of the ladder body 2, and the inclined portion 3b side (lower side in FIG. 2) with respect to the vertical portion 3a. Is the lower side, and the opposite side (the upper side in FIG. 2) is the upper side.

  The support column 3 is a metal member made of aluminum or an aluminum alloy, and is a longitudinal member having a “U” -shaped cross-sectional shape for the purpose of ensuring strength and the like. The column 3 is a portion having a U-shaped cross-sectional shape, and includes a side wall portion 11 serving as a wall portion facing each other in the pair of columns 3 and a side wall portion 11 continuously from both ends of the side wall portion 11. And a pair of end wall portions 12 that are perpendicular to each other and face each other.

  The pair of support columns 3 are provided with the side wall 11 side as the inner side, that is, with the open side of the “U” -shaped cross section facing the left and right outer sides. The column 3 is formed, for example, by bending a linear extruded product having a U-shaped cross section into a predetermined length and then bending it at a predetermined position, whereby a vertical portion 3a and an inclined portion 3b. It is comprised as a member which has. Further, a cap-like end tool 5 having a function of preventing lateral deviation is attached to the lower end portion of the support column 3 in a state where it is fitted.

  The crosspiece 4 is a metal member made of aluminum or an aluminum alloy, and is a linear member having an erection direction with respect to the pair of support columns 3 as an axial 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 the present embodiment, between the pair of support columns 3 constituting the ladder body 2, a total of six traversers 4, two between the vertical portions 3 a and four between the inclined portions 3 b, are arranged in the vertical direction of the ladder body 2. They are provided at substantially equal intervals. The two crosspieces 4 constructed between the vertical portions 3a have the same length (dimension in the axial direction). One (upper side) of the two step bars 4 provided between the vertical portions 3 a is provided between the upper end portions of the vertical portions 3 a, that is, the upper end portions of the columns 3. Further, the length of the four crosspieces 4 installed between the inclined portions 3b is longer as the stepped crosspieces 4 are arranged on the lower side according to the interval between the pair of inclined portions 3b. The six traversers 4 installed between the pair of pillars 3 in the ladder body 2 have a configuration other than the length, specifically, a common configuration with respect to a cross-sectional shape and a longitudinal end shape which will be described later. Have.

  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. That is, the joint bracket 6 is a member that forms a hinge portion between the columns 3 to be connected to each other, and the columns 3 corresponding to the left and right sides of the stepladder 1 are provided at the upper ends of the columns 3. They are connected to each other via a pair of joint fittings 6 by being connected to each other with the left-right direction as a rotation axis direction. 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. The joint fitting 6 has the fixing portion 6a on the inner surface (inner side in the left-right direction) of the side wall portion 11 of the support column 3, that is, on the surface opposite to the open side in the “U” shape of the cross section of the support column 3. In the state of being along, 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 connected column 3. 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 rotation axis direction, the left and right sides are opened between the support columns 3 connected to each other via the joint bracket 6. A fastener 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 reversed “V” so as to follow 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 ladder bodies 2 can be opened by a predetermined amount or more. Be regulated.

  The stopper metal fitting 8 is a half-folded 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 stopper 8 is pivotally supported so that an end on one side thereof, that is, an end of one plate-like member opposite to the connecting side with respect to the other plate-like member can be rotated to a predetermined position on the upper end of the column 3. It is provided in the state that was done. 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 folding-type stopper 8 is bent in a substantially reverse “V” shape by the rotation of the two plate-like members between the ladder bodies 2 that are substantially parallel to each other. It becomes.

  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 the stepladder 1 is used as a ladder, the restriction of the rotation by the locking bracket 8 is released, and the stepladder 1 is in an open state until the pair of ladder bodies 2 are straight in a side view (FIG. 3). reference). 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. And in the ladder-like stepladder 1, the stopper metal fitting 8 is set 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.

  The stepladder 1 according to the present embodiment as described above includes the shapes of the column 3 and the step rail 4 and the like, and has a characteristic structure with respect to the fixing structure of the column 3 and the step rail 4 coupled to each other and the manufacturing method thereof. . Hereinafter, these will be described in detail.

[Structure of the fixing structure of the pedestal]
A fixing structure (hereinafter referred to as a “step rail fixing structure”) of the tread bar 4 included in the stepladder 1 according to the present embodiment will be described. The step rail fixing structure according to the present embodiment includes a pair of struts 3 and a step rail 4 laid across the pair of struts 3, and fixes the end of the step rail 4 to the column 3. . In each ladder body 2 constituting the stepladder 1, the traversing bridge 4 constructed between the left and right columns 3 is coupled to the pair of columns 3 by fixing the ends on both sides in the axial direction to the columns 3. It becomes a state. In the present embodiment, the end portion of the traverse 4 is fixed to the side wall portion 11 that is a surface portion orthogonal to the left-right direction in the column 3 having a U-shaped cross section.

  As described above, the tram 4 is installed between the pair of columns 3 and between the vertical portions 3a and between the inclined portions 3b. Therefore, in the ladder body 2, there are a fixing structure for the vertical portion 3 a of the support column 3 and a fixing structure for the inclined portion 3 b of the support column 3 as the footrail fixing structure. According to the step rail fixing structure of the present embodiment, a common fixing structure and manufacturing method are applied to the fixing of the step rail 4 to the vertical portion 3a and the fixing of the step rail 4 to the inclined portion 3b.

  First, a step rail fixing structure in the vertical portion 3a of the column 3 will be described with reference to FIGS. 5 is a partial cross-sectional enlarged perspective view of the AA position in FIG. 4, FIG. 6 is a B arrow view in FIG. 4, and FIG. 7 is a CC arrow cross section in FIG. 8 is a cross-sectional view taken along the line DD in FIG. 7, FIG. 10 (a) is a cross-sectional view taken along the arrow E in FIG. 9, and FIG. It is.

  As shown in FIGS. 4 to 7, in the step rail fixing structure in the vertical portion 3 a of the column 3, the step rail 4 is an upper side wall portion which is a portion constituting the vertical portion 3 a among the side wall portions 11 constituting the column 3. It is fixed to 11a. The upper side wall portion 11 a is a plate-like portion perpendicular to the axial direction (longitudinal direction) of the step rail 4 along the left-right direction, and plate surfaces on both sides in the left-right direction are used as support surfaces for the step rail 4. That is, the upper side wall portion 11a serves as a support surface that is perpendicular to the axial direction of the traverse 4 and has an inner support surface 11x that serves as an inner (left and right inner) support surface between the pair of columns 3 and an outer side (left and right outer). And an outer support surface 11y serving as a support surface.

  On the other hand, the tram 4 includes a main body portion 14 positioned between the side wall portions 11 of the left and right support columns 3 and a flange portion 15 as a clamping portion provided on both the left and right outer sides of the main body portion 14. The crosspiece 4 forms a first clamping surface 21 that contacts the inner support surface 11x of the upper side wall portion 11a at the longitudinal end portion of the main body portion 14, and the outer support surface of the upper side wall portion 11a at the flange portion 15. The 2nd clamping surface 22 which contacts 11y is formed. That is, in a state in which the crosspiece 4 is fixed to the column 3, the first clamping surface 21 that is an end surface in the longitudinal direction of the main body portion 14 and the second clamping surface 22 of the flange portion 15 that faces the first clamping surface 21. Thus, the upper side wall portion 11a is sandwiched from both the left and right sides.

  The main body portion 14 is a portion constituting most of the step rail 4 other than the left and right end portions, and the inner support surface 11x of the support surfaces of the upper side wall portion 11a as end surfaces on both sides of the step rail 4 in the axial direction. The 1st clamping surface 21 which contacts is formed. That is, the main body portion 14 is a portion located between the left and right side wall portions 11, that is, between the left and right inner support surfaces 11 x in a state in which the step rail 4 is installed between the left and right support columns 3, and The first clamping surface 21 is brought into contact with the surface 11x.

  The flange portion 15 is a portion on both outer sides of the main body portion 14 in the longitudinal direction of the step rail 4, that is, a portion constituting both left and right end portions of the step rail 4, and is opposed to the first clamping surface 21 of the main body portion 14 and is an upper portion The 2nd clamping surface 22 which contacts the outer side support surface 11y among the support surfaces which the side wall part 11a has is formed. That is, the flange portion 15 is a portion that is mostly outside the left and right side wall portions 11, that is, outside the outer support surface 11y in the left-right direction in a state in which the step rail 4 is installed between the left and right support columns 3. Yes, the second clamping surface 22 is brought into contact with the outer support surface 11y. And the collar part 15 becomes a part which press-clamps the side wall part 11 (upper side wall part 11a) with the main-body part 14. FIG.

  The flange portion 15 is a portion that protrudes from the first clamping surface 21 that is the left and right end surfaces of the main body portion 14, passes through the insertion hole 16 (see FIG. 8) formed in the side wall portion 11, and A diameter-enlarged portion with respect to the hole diameter of the insertion hole 16 is formed on the outer side (outer support surface 11y side), and the second clamping surface 22 contacts the peripheral portion of the insertion hole 16 on the outer support surface 11y. The flange portion 15 has a flange-shaped main body portion 15a which is an enlarged diameter portion located outside the side wall portion 11 and a cylindrical shape (annular shape) protruding from the first clamping surface 21 of the main body portion 14 by the wall thickness of the side wall portion 11. ) And a cylindrical portion 15b that connects the main body portion 14 and the bowl-shaped main body portion 15a.

  The cylindrical portion 15b is a portion located in the insertion hole 16 of the side wall portion 11, and the first clamping surface 21 and the second clamping surface that are opposed to each other on both the left and right sides (both sides in the cylindrical axis direction) of the cylindrical portion 15b. A surface 22 is formed. And the part which forms the penetration hole 16 in the side wall part 11 (periphery part of the penetration hole 16) will be in the state clamped by the 1st clamping surface 21 and the 2nd clamping surface 22. As shown in FIG. That is, the main body part 14 and the bowl-shaped main body part 15a are respectively positioned on both wall surfaces of the side wall part 11 via the cylindrical part 15b, and the outer side of the cylindrical part 15b in the radial direction when viewed from the axial direction of the traverse 4 In addition, a first clamping surface 21 and a second clamping surface 22 that sandwich the side wall portion 11 from the left and right are formed.

  Specifically, the bowl-shaped main body part 15a constituting the collar part 15 includes an inner annular part 15c and an outer annular part 15d, which are annular plate-like parts that are folded on each other. The inner annular portion 15c is an annular plate-shaped portion that expands along a surface substantially perpendicular to the axial direction of the traverse 4 from the end portion of the cylindrical portion 15b opposite to the main body portion 14 side, The inner surface (main body part 14 side) is the second clamping surface 22. The outer annular portion 15d is an annular plate-like portion like the inner annular portion 15c, and overlaps the outer side in the left-right direction with respect to the inner annular portion 15c. That is, each of the inner annular portion 15c and the outer annular portion 15d is a plate-like annular portion whose plate surface is a surface perpendicular to the left-right direction in the same manner as the inner support surface 11x of the side wall portion 11 and the like. The flange-shaped main body portion 15a is formed in a state of being concentrically overlapped with the diameter-shaped portion 15b.

  In the present embodiment, the bowl-shaped main body part 15a is a part formed by bending a cylindrical part as described later, and therefore, the inner annular part 15c and the outer side constituting the bowl-shaped main body part 15a. The annular portion 15d is connected to each other at the peripheral edge portion of the bowl-shaped main body portion 15a. In the present embodiment, the outer annular portion 15d has a slightly larger inner diameter in the annular outer shape than the inner diameter of the cylindrical portion 15b that is the inner diameter of the inner annular portion 15c. In other words, as shown in FIG. 7, the inner diameter D1 of the outer annular portion 15d is slightly larger than the inner diameter D2 (of the tubular portion 15b) of the inner annular portion 15c. Therefore, the exposed portion 15e exposed in an annular shape exists along the inner periphery of the outer annular portion 15d at the inner peripheral edge portion of the inner annular portion 15c in the axial view of the step rail 4 (see FIG. 6). However, the flange-shaped main body portion 15a has a structure in which the inner diameter of the outer annular portion 15d is approximately the same as or larger than the inner diameter of the inner annular portion 15c. The edge may be structured to be folded toward the inner annular portion 15c (inside the cylindrical portion 15b).

  In the present embodiment, as shown in FIG. 9, the eaves portion 15 that constitutes the traverse 4 is formed by deforming the cylindrical projecting portions 23 provided at both ends of the main body portion 14 by a predetermined processing method. It is the part which was done. The cylindrical projecting portion 23 has a substantially cylindrical shape with the longitudinal direction of the tread bar 4 as the cylinder axis direction, and is provided in a form projecting from the first clamping surface 21 of the main body portion 14. The cylindrical projecting portion 23 has a cross-sectional shape having substantially the same shape and size with respect to the entire cylindrical axis direction. The cylindrical protrusions 23 at the left and right ends are provided on concentric shafts.

  The flange portion 15 is formed by bending and deforming the cylindrical protruding portion 23 provided in this manner so that the diameter of the cylindrical protruding portion 23 increases from the substantially central position in the cylindrical axis direction to the outside in the radial direction. The cylindrical projecting portion 23 is a process for forming the flange portion 15 in a state of penetrating the insertion hole 16 formed in the side wall portion 11, that is, a state of projecting outward from the inside of the side wall portion 11 through the insertion hole 16. Receive. Therefore, a flange-shaped main body portion 15 a of the flange portion 15 is formed by a portion protruding from the insertion hole 16 of the cylindrical protrusion portion 23 to the outside of the side wall portion 11, and the base of the cylindrical protrusion portion 23 located in the insertion hole 16 is formed. The end portion becomes the cylindrical portion 15b.

  As described above, the flange portion 15 serving as a holding portion that holds the side wall portion 11 together with the main body portion 14 has the cylindrical protruding portion 23 that is a portion protruding in a cylindrical shape from the first holding surface 21 of the main body portion 14. It is a bowl-shaped part formed by being deformed in a state of penetrating through the insertion hole 16 formed in. Specifically, although the details will be described later, a predetermined pressing die is used, and the pressing force in a direction in which the cylindrical protruding portion 23 faces the protruding direction (both lateral directions in the left-right direction) from the first clamping surface 21. By receiving, the flange part 15 is formed by bending. As the cylindrical protrusion 23 for forming the flange 15 is formed, the upper side wall 11 a is pressed and clamped between the main body 14 and the flange 15.

  The step 4 will be described in detail. The step rail 4 of the present embodiment includes a hollow cylindrical core portion 24 that constitutes an axial core portion thereof, and a pair of hollow tread surface forming portions 25 provided on the outer peripheral side of the cylindrical core portion 24. . In the case where the step rail 4 is formed of an extruded product, the cylindrical core portion 24 and the tread surface forming portion 25 are an integral part having a predetermined cross-sectional shape.

  The cylindrical core portion 24 has an annular shape with a cross-sectional shape, and the cylindrical protruding portion 23 is formed by both end portions in the axial direction. The cylindrical core portion 24 is a cylindrical portion as a whole in the step rail member 4A, which is the step rail 4 in a state before being subjected to the processing for forming the flange portion 15 by the cylindrical protrusion 23. Both end portions in the axial direction are referred to as cylindrical projecting portions 23. The cylindrical core portion 24 is provided over the entire longitudinal range of the main body portion 14 in the crosspiece member 4A to constitute the main body portion 14 and linearly extends from the portion constituting the main body portion 14. 14, projecting from the first sandwiching surface 21, which is the left and right side end surfaces of the left and right sides, the left and right side cylindrical projections 23 are formed on the concentric axes. That is, the cylindrical core part 24 is a part having the same cross-sectional shape as the cylindrical protruding part 23, and has an insertion shape corresponding to the hole shape of the insertion hole 16 into which the cylindrical protruding part 23 is inserted.

  In the present embodiment, the cylindrical projecting portion 23 is formed by removing the tread surface forming portion 25 at both ends of the step rail 4 (step rail member 4A) and exposing the cylindrical core portion 24 as described later. It has been done. In addition, in the crosspiece member 4 </ b> A, the cylindrical core portion 24 is provided so as to be within the range of the outer shape of the pair of tread surface forming portions 25 when viewed in the axial direction.

  The tread surface forming portion 25 is a portion that is provided outside the cylindrical core portion 24 and forms a flat tread surface 25s. The tread surface forming portion 25 constitutes the main body portion 14 together with an intermediate portion other than both end portions (cylindrical protruding portions 23) of the cylindrical core portion 24 in the tread bar 4 (the tread bar member 4A).

  The tread surface forming portion 25 is the center of the cylindrical core portion 24 in the axial direction view (side view) of the tread bar 4 in the tread bar 4 in a state of being laid between the pair of support columns 3 (hereinafter referred to as “installed state”). It is provided at two locations so as to be substantially symmetrical vertically with a straight line passing through the position in the left-right direction (left-right direction in FIGS. 10A and 10B) as a center line. That is, the pair of tread surface forming portions 25 are provided so as to have a vertically symmetrical shape above and below the cylindrical core portion 24. In the pedestrian crossing 4, one of the two tread forming portions 25 is provided on the outer side (outer peripheral side) of the upper portion of the cylindrical core portion 24, and the other tread forming portion is provided. 25 is provided on the outer side (outer peripheral side) of the lower part of the cylindrical core part 24.

  In the present embodiment, the tread surface forming portion 25 is a hollow portion having a cross-sectional shape and an outer shape along a substantially triangular shape, and the tread surface 25s is formed by one side portion in the cross-sectional shape. Specifically, as shown in FIGS. 10A and 10B, the tread surface forming portion 25 includes a main surface portion 25 a serving as a side portion forming the tread surface 25 s in the cross sectional shape of the tread bar 4, and a cross sectional shape. And 2 main connecting surface portions 25b and 25c, which are portions having a substantially triangular shape together with the main surface portion 25a. The main surface portion 25a is a portion provided so as to be tangential to the substantially annular cylindrical core portion 24 with a dimension longer than the outer diameter of the cylindrical core portion 24 in the cross-sectional shape. Each of the connection surface portions 25b and 25c is a straight portion that forms an acute angle with the main surface portion 25a in the cross-sectional shape, one end side is connected to the end portion of the main surface portion 25a, and the other end side is the outer periphery of the cylindrical core portion 24. It is a part connected to the cylindrical core part 24 in a manner in contact with the surface. In the cross-sectional shape, an acute angle portion formed by the main surface portion 25a and the connection surface portions 25b and 25c has a rounded angle curved in an R shape.

  The main surface portion 25a and the connection surface portions 25b and 25c constituting the tread surface forming portion 25 are strip-like portions along the longitudinal direction of the tread bar 4 so as to form a common cross-sectional shape in the main body portion 14 of the tread bar 4. Is provided. Therefore, the tread surface forming portion 25 has a substantially triangular shape with a cross-sectional shape in which the arc surface portion including the portion with which the main surface portion 25a contacts the cylindrical core portion 24 is held by the two connection surface portions 25b and 25c. The outer shape along the substantially triangular prism shape formed by the main surface portion 25 a along the two connecting surface portions 25 b and 25 c is formed, and the hollow portion is configured together with the outer peripheral surface of the cylindrical core portion 24.

  Of the two upper and lower portions, the upper tread forming portion 25 has a tread 25 s in the erected state in the direction perpendicular to the vertical direction in the side view of the ladder body 2 (in FIGS. 10A and 10B). With respect to the left-right direction), the ladder body 2 is provided so as to incline downward toward the climbing surface side (right side in the figure). The degree of inclination of the tread surface 25s is adjusted so that the tread surface 25s is substantially along a horizontal plane in a state where the ladder body 2 is inclined with respect to the vertical direction when the stepladder 1 is used as a stepladder. That is, the plate-like main surface portion 25a forming the flat tread surface 25s is formed so as to incline the tread surface 25s in a predetermined direction. Note that a non-slip-shaped portion such as a ridge portion (groove-shaped portion) along the longitudinal direction of the tread bar 4 is appropriately formed on the tread surface 25s.

  Since the main surface portion 25a forming the tread surface 25s is inclined as described above, in the configuration in which the pair of tread surface forming portions 25 are provided vertically symmetrically as described above, between the main surface portions 25a of the upper and lower tread surface forming portions 25. Is narrow on the climbing surface side (the right side in FIGS. 10A and 10B) of the ladder body 2 and wide on the anti-climbing surface side (the left side in FIG. 10). In other words, with respect to the upper and lower tread surface forming portions 25, the interval between the ridge line portions by the main surface portion 25a and the connecting surface portion 25b on the climbing surface side is the interval between the ridge line portions by the main surface portion 25a and the connecting surface portion 25c on the anti-climbing surface side. It is narrower than. In such a configuration, the tread surface forming portion 25, together with the cylindrical core portion 24, has a substantially “M” shape on the climbing surface side and a substantially “W” shape on the anti-climbing surface side in the cross-sectional shape. Make.

  In the present embodiment, the main surface portion 25a forming the tread surface 25s is connected to the cylindrical core portion 24 so as to be tangential to the substantially annular cylindrical core portion 24 in a cross-sectional view. For this reason, between the cylindrical core part 24 and each tread surface formation part 25, the hollow part is formed in two places, the climbing surface side and the anti-climbing surface side. Specifically, on the climbing surface side, the connecting surface portion 25b on the climbing surface side, the portion on the climbing surface side of the main surface portion 25a that forms a corner portion together with the connecting surface portion 25b, and the peripheral wall portion of the cylindrical core portion 24 A hollow portion 26a having a substantially triangular prism shape is formed. Further, on the anti-climbing surface side, the connection surface portion 25c on the anti-climbing surface side, the portion on the anti-climbing surface side of the main surface portion 25a that forms a corner portion together with the connection surface portion 25c, and the peripheral wall portion of the cylindrical core portion 24 A hollow portion 26b having a substantially triangular prism shape is formed.

  Of the treads 25s on both sides formed by the tread forming parts 25 positioned above and below the cylindrical core part 24, one tread 25s is located on the upper side when the stepladder 1 is used as a stepladder. It functions as 25s. The other tread surface 25s is in an inverted state (a state in which the side where the distance between the pair of support columns 3 is relatively wide is on the upper side) depending on the direction of the ladder when the stepladder 1 is used as a ladder. And functions as a tread 25s.

  As described above, in the configuration including the cylindrical core portion 24 and the tread surface forming portion 25, the tread surface forming portion 25 is a portion that forms the tread surface 25 s on the outer peripheral side of the cylindrical core portion 24, and is viewed in the cylinder axis direction. Thus, an overhanging portion that projects outward from the cylindrical core portion 24 is configured. That is, the tread surface forming portion 25 projects outward with respect to the cylindrical core portion 24, thereby forming stepped portions with respect to the cylindrical projecting portion 23 at both ends of the stepped rail 4, and the stepped surface is formed on the stepped rail 4. The first clamping surface 21 is perpendicular to the axial direction. The shape of the tread surface forming portion 25 is not limited to the present embodiment, and may be a predetermined shape portion that forms the tread surface 25s on the outer peripheral side of the cylindrical core portion 24. Therefore, the tread surface forming portion 25 may be, for example, a plate-like portion that forms a tread surface, instead of a portion that forms a hollow portion as in the present embodiment.

  Further, in the configuration in which the traverse 4 is installed in a state of passing through the insertion hole 16 of the column 3, the insertion hole 16 and the tram 4 have a shape that restricts relative rotation of the tram 4 with respect to the column 3. . As described above, in the state where the tram 4 is fixed to the column 3, the tubular portion 15 b formed by the proximal end portion of the tubular projecting portion 23 of the traverse member 4 </ b> A is replaced with the insertion hole 16 of the side wall portion 11. Located within. As described above, the tubular projecting portion 23 has a cross-sectional shape having the same shape and dimensions as a whole, and the tubular portion 15 b that is the base end portion of the tubular projecting portion 23 is inserted into the insertion hole 16. It becomes a state. That is, the hole shape of the insertion hole 16 and the outer shape of the cross-sectional shape of the cylindrical portion 15b, that is, the outer shape of the cross-sectional shape of the cylindrical projecting portion 23 of the stepping bar member 4A are substantially the same shape and size. .

  Therefore, the hole shape of the insertion hole 16 and the cross-sectional shape of the cylindrical protrusion 23 having substantially the same shape and dimensions as each other, that is, the insertion shape of the cylindrical protrusion 23 with respect to the insertion hole 16 are determined as follows. It has a shape that regulates relative rotation with respect to. In this embodiment, as such an insertion shape, a shape in which a pair of linear portions parallel to each other is formed at positions facing each other in the circumferential shape (see FIG. 8).

  Therefore, the insertion hole 16 has a pair of linear portions 16m parallel to each other at positions facing each other in the inner peripheral portion having a substantially circular hole shape. Moreover, the cylindrical part 15b of the collar part 15 has a pair of linear part 15m mutually parallel in the position which mutually opposes in the substantially annular | circular shaped external shape. Moreover, the cylindrical protrusion part 23 which makes a base end part the cylindrical part 15b has a pair of plane part 23m mutually parallel in the position which mutually opposes in the surrounding wall part which makes a substantially cylindrical external shape. The flat surface portion 23m is a flat surface portion that forms a predetermined two-surface width in the substantially cylindrical tubular protrusion 23. In the present embodiment, the pair of straight portions 16m, the pair of straight portions 15m, and the pair of flat portions 23m are in a direction (the left-right direction in FIG. 8) in which the opposing directions are substantially orthogonal to the vertical direction in a side view. It is formed to become.

  As described above, in the treadle fixing structure of the present embodiment, the cylindrical protruding portion 23 and the insertion hole 16 have an insertion shape in which relative rotation of the treadle 4 with respect to the support column 3 around the axial direction is restricted. The insertion shape of the cylindrical protruding portion 23 and the insertion hole 16 is not limited to the present embodiment, and any shape that restricts the relative rotation of the traverse 4 with respect to the column 3 may be used. As such an insertion shape, various shapes such as an elliptical shape, a polygonal shape, a star shape, and a gear shape can be employed. That is, the insertion shape of the cylindrical protrusion 23 and the insertion hole 16 may be an irregular shape with respect to the circumferential shape that enables relative rotation of the traversing rail 4 with respect to the column 3.

  Next, the structure for fixing the crosspiece at the inclined portion 3b of the column 3 will be described with reference to FIGS. 12 is a partially sectional enlarged perspective view of the position FF in FIG. 11, FIG. 13 is a sectional view taken along arrow G in FIG. 11, and FIG. 14 is a sectional view taken along arrow H-H in FIG. 15 is a partial cross-sectional view taken along line JJ in FIG. In addition, the description of the contents common to the traverse fixing structure in the vertical portion 3a of the column 3 will be omitted as appropriate.

  In the step-bar fixing structure in the inclined portion 3b, the shape of the step-bar 4 is the same as that of the step-bar fixing structure in the vertical portion 3a. On the other hand, since the inclined portion 3 b of the support column 3 is inclined so as to form a downwardly expanding shape between the pair of support columns 3, the inclined portion 3 b of the side wall portion 11 that configures the support column 3 is formed. A certain lower side wall portion 11b is inclined along the inclination of the inclined portion 3b. Therefore, in the inclined portion 3b of the column 3, in order to correspond to the step rail 4 having a shape corresponding to the upper side wall portion 11a in the step rail fixing structure in the vertical portion 3a, the axial direction of the step rail 4 is the same as the upper side wall portion 11a. A vertical surface portion 31 that is a plate-like portion perpendicular to the (left-right direction) is provided.

  As described above, in the step rail fixing structure of the present embodiment, the inclined portion 3b of the column 3 is horizontally mounted between the pair of columns 3 as a part to which the end portion of the column 4 is fixed (installed state). ) Including vertical surface portions 31 as vertical portions that form support surfaces perpendicular to the axial direction of the traverse 4 on both the inner and outer sides of the column 3. In other words, in the step rail fixing structure in the inclined portion 3b, the vertical surface portion 31 is similar to the upper side wall portion 11a in the vertical portion 3a, and the first clamping surface 21 formed by the main body portion 14 in the step rail 4 and the flange portion. 15 and a second clamping surface 22 formed by 15, which is a part that is pressed and clamped. Accordingly, the vertical surface portion 31 is a portion in which the insertion holes 16 through which the left and right end portions of the step rail 4 pass are formed, and the vertical surface portions 31 of the columns 3 are parallel to each other between the pair of columns 3. It becomes a surface part.

  As shown in FIGS. 11 to 14, in the step rail fixing structure in the inclined portion 3 b of the column 3, the step rail 4 is fixed to the lower side wall portion 11 b. The lower side wall portion 11b has a vertical surface portion 31 that is a plate-like portion perpendicular to the axial direction (longitudinal direction) of the step rail 4 along the left-right direction. The supporting surface of the crosswalk 4 is used. That is, the vertical surface portion 31 serves as a support surface perpendicular to the axial direction of the traverse 4, and an inner support surface 31 x serving as an inner (left and right inner) support surface between the pair of support columns 3 and an outer (left and right outer) support surface. It has the outer side support surface 31y used as a support surface.

  The vertical surface portion 31 is provided in the lower side wall portion 11b so as to have a size including at least a portion sandwiched between the first sandwiching surface 21 and the second sandwiching surface 22 as a portion where the insertion hole 16 is formed. In the present embodiment, the vertical surface portion 31 has a size including all of the flange-shaped main body portion 15a of the flange portion 15 in the axial direction view (side view) of the crosspiece 4, and the extending direction of the column 3 is elongated. It has a substantially rectangular shape as a direction.

  The vertical surface portion 31 is provided via the inclined surface portion 32 in the lower side wall portion 11b. In other words, the slope portion 32 is a portion surrounding the periphery of the substantially rectangular vertical surface portion 31 and is a portion that forms a step of the vertical surface portion 31 with respect to the overall slope-shaped portion of the lower side wall portion 11b. is there. On the upper side of the vertical surface portion 31, the slope portion 32 becomes a slope portion 32 a that gradually inclines from the inner side to the outer side in the left-right direction from the upper side to the lower side so that the lower side wall portion 11 b bulges outward in the left-right direction. In addition, the inclined surface portion 32 is formed on the lower side of the vertical surface portion 31 with an inclined surface portion 32b that gradually inclines from the inner side to the outer side in the left-right direction from the upper side to the lower side so that the lower side wall portion 11b bulges in the left-right direction. Become.

  The vertical surface portion 31 has a portion corresponding to a position where the step rail 4 is supported in an overall slope-shaped portion constituting the lower side wall portion 11b with respect to the axial direction of the step rail 4 by predetermined processing such as embossing. In other words, it is formed together with the slope portion 32 by being bent so as to be a vertical surface portion. In addition, as a process for forming the vertical surface part 31 and the slope part 32, even if it performs simultaneously the drilling process for forming the insertion hole 16 which the cylindrical protrusion part 23 of 4 A of traverse members penetrates. Good.

  As described above, in the inclined portion 3 b of the support column 3, the lower side wall portion 11 b has the vertical surface portion 31, so that the vertical surface portion 31 is the same as the upper side wall portion 11 a in the vertical portion 3 a of the support column 3 in the trawl fixing structure. It becomes a portion that is pressed and clamped by the main body portion 14 and the flange portion 15 of the step rail 4, and the end portion in the axial direction of the step rail 4 is fixedly supported by the column 3. That is, in the step rail fixing structure in the inclined portion 3 b of the column 3, the first clamping surface 21 formed by the main body portion 14 of the step rail 4 is in contact with the inner support surface 31 x of the vertical surface portion 31, and the flange portion 15 The formed second clamping surface 22 is in contact with the outer support surface 31y of the vertical surface portion 31, and the vertical surface portion 31 is sandwiched from both the left and right sides by the first clamping surface 21 and the second clamping surface 22 facing each other. Become.

  Therefore, in the step rail fixing structure in the inclined portion 3b of the column 3, the main body portion 14 contacts the inner support surface 31x of the support surfaces of the vertical surface portion 31 as end surfaces on both sides in the axial direction of the step rail 4. The first clamping surface 21 is formed. The flange 15 forms a second clamping surface 22 that faces the first clamping surface 21 of the main body 14 and contacts the outer support surface 31 y of the support surfaces of the vertical surface portion 31. That is, the flange portion 15 is a portion of the pedestrian crossing 4 in the erected state that is positioned on the outer side of the left and right side wall portions 11, that is, on the outer side of the vertical support portion 31 in the left-right direction. The second clamping surface 22 is brought into contact with the surface 31y. And the collar part 15 becomes a part which press-clamps the side wall part 11 with the main-body part 14, specifically, the vertical surface part 31 of the lower side wall part 11b.

[Manufacturing method of the fixing structure of the crosspiece]
Then, the manufacturing method of the foot fixing structure according to this embodiment will be described with reference to FIGS. Since the method for manufacturing the footrail fixing structure according to the present embodiment is performed in the same manner for each of the vertical portion 3a and the inclined portion 3b of the support column 3, the following description will be mainly given of the case of the inclined portion 3b.

  The manufacturing method according to the present embodiment includes the above-described treadle fixing structure, that is, a pair of support columns 3 that are vertical members, and a treadle 4 that is horizontally mounted between the pair of support columns 3. This is a method for manufacturing a structure in which is fixed to the column 3. Therefore, in the manufacturing method according to the present embodiment, first, a step of preparing each of the column 3 and the footpiece member 4A is performed.

  In the step of preparing the column 3, as described above, the vertical portion 3 a and the inclined portion 3 b are provided, and the end portion of the traverse 4 is fixed to the inner support surface 31 x and the outer support surface 31 y and the insertion hole. A support column 3 provided with a vertical surface 31 on which 16 is formed is prepared. Specifically, such a support | pillar 3 is manufactured as follows, for example.

  First, a linear molded part having a U-shaped cross-sectional shape including a side wall portion 11 and a pair of end wall portions 12 is manufactured by extrusion molding using aluminum or an aluminum alloy as a material. Next, the extruded part having a U-shaped cross section is cut into a predetermined length suitable as a member constituting the ladder body 2.

  Next, by performing processing using a predetermined pressing die such as embossing on an extrusion molded part having a predetermined length, the fixed portion of the crosspiece 4 on the lower side wall portion 11b of the inclined portion 3b is The vertical surface portion 31 is formed together with the slope portion 32 by being partially bent. In the step of forming the vertical surface portion 31, drilling for forming the insertion hole 16 is simultaneously performed. That is, in processing using a predetermined pressing die, the lower side wall portion 11b is formed by bending to form the vertical surface portion 31, and the insertion hole 16 is formed in a portion corresponding to the vertical surface portion 31 of the lower side wall portion 11b. Processing is performed at the same time. However, the step of forming the vertical surface portion 31 and the step of forming the insertion hole 16 may be performed as separate steps. Further, as described above, the insertion hole 16 is formed with a hole having linear portions 16m at two locations facing each other in the hole diameter direction (see FIGS. 8 and 15).

  And the linear extrusion molded product in which the vertical surface part 31 and the insertion hole 16 were formed is bent by bending, and the inclined part 3b with respect to the vertical part 3a is formed. In addition, after performing the bending process for forming the inclined part 3b, the process of forming the vertical surface part 31 and the insertion hole 16 may be performed.

  In this way, the support column 3 having a cross-section “U” shape, having the inclined portion 3 b and provided with the vertical surface portion 31 in which the insertion hole 16 is formed in the inclined portion 3 b is manufactured and prepared. The material of the support 3 is not limited to aluminum or aluminum alloy, but may be other metal material or resin material, but aluminum or aluminum alloy is used from the viewpoint of ease of processing and weight reduction. Preferably used.

  In the step of preparing the crosspiece member 4A, as described above, the main body portion 14 that forms the first clamping surface 21 that contacts the inner support surface 31x of the vertical surface portion 31 as the end surfaces on both sides in the axial direction, and the first clamping surface 21 4A. A tread bar member 4A constituting the tread bar 4 is prepared by being fixed between the pair of support columns 3 and having a cylindrical projecting portion 23 that is a portion projecting in a cylindrical shape from the upper end. Specifically, such a crosspiece member 4A is manufactured as follows, for example.

  First, a cylindrical cylindrical core portion 24 constituting the core portion of the tread bar 4 and two tread surfaces formed symmetrically around the cylindrical core portion 24 by extrusion molding using aluminum or an aluminum alloy as a material. A linear molded part having the forming part 25 is manufactured. That is, such an extrusion-molded part includes a hollow cylindrical core portion 24 having an annular shape in cross section, and a tread surface forming portion 25 that is provided outside the cylindrical core portion 24 and forms a flat tread surface 25s. It becomes a linear molded part having. In addition, the tread surface forming portion 25 is a hollow portion having a cross-sectional shape that follows a substantially triangular shape, and a side portion on one side in the cross-sectional shape is a main surface portion 25a that forms the tread surface 25s. The cross-sectional shape of such an extrusion-molded part is the same as the cross-sectional shape of the main body 14 of the crosspiece 4 (see FIG. 10B).

  Next, this extrusion molded part is cut into a predetermined length suitable as a member constituting the ladder body 2. Here, the extrusion molded part is cut to a length corresponding to the interval between the pair of support columns 3 having the vertical portion 3a and the inclined portion 3b and extending downward in the inclined portion 3b. In this way, first, as shown in FIG. 16, a linear molded part (hereinafter referred to as “step rail molded part”) 4B having a cylindrical core part 24 and a pair of tread surface forming parts 25 is prepared. The process to perform is performed. The crosspiece molded part 4B has a shape that forms a common cross-sectional shape (see FIG. 10B) in the entire longitudinal direction (extrusion direction).

  Then, the process of forming the cylindrical protrusion part 23 by exposing the cylindrical core part 24 by removing the portions of the tread surface forming part 25 at both ends of the molded part 4B for the crosspiece is performed. In other words, at both ends in the longitudinal direction of the molded part 4B for the treadle, a tubular surface that forms the tubular protrusion 23 by cutting off the portion of the tread surface forming portion 25 around the tubular core portion 24 by a predetermined cutting process or the like. Both end portions of the core portion 24 are cut out. Specifically, for example, a cutting tool is used, and one of the cutting tool and the molded part 4B for the crosspiece is fixedly supported by a predetermined mold or the like, and the other is rotated. The cylindrical core part 24 is cut out at both end portions of the molded part 4B for the foot crossing by rotational cutting while the molded part 4B rotates relatively.

  As a result of such processing, cylindrical protrusions 23 are formed at both ends of the molded part 4B for the treadle, and at the same time, a first sandwiching surface serving as an end surface of the main body 14 as a cut-out end surface of the tread surface forming portion 25. 21 is formed. As a result, a crosspiece member 4A as shown in FIG. 9 is formed. In addition, about the plane part 23m of the cylindrical protrusion part 23 which forms the two linear parts 15m which mutually oppose in the cylindrical part 15b of the final step-bar fixing structure, it is the cylindrical core part 24 as a shaping | molding shape in extrusion molding. The flat surface portion 24m corresponding to the flat surface portion 23m may be formed, and the cylindrical core portion 24 after being cut out at both ends of the molded part 4B for the crosspiece is subjected to a predetermined process to be extruded. You may form the plane part 23m in a process different from shaping | molding.

  Thus, it has the cylindrical core part 24 and the tread surface formation part 25, and has the cylindrical protrusion part 23 formed by the both ends of the axial direction of the cylindrical core part 24, and the cylindrical protrusion part 23 protrudes. The footpiece member 4A having the first clamping surface 21 serving as the base end surface is manufactured and prepared. In addition, the processing method for removing the tread forming part 25 and exposing the cylindrical core part 24 at both ends of the molded part 4B for the tread is not particularly limited. Further, as the material of the footpiece member 4A, similar to the column 3, other metal material or resin material may be used, but aluminum or aluminum alloy is preferably used from the viewpoint of ease of processing and weight reduction. It is done.

  After the support column 3 and the footpiece member 4A are prepared as described above, the cylindrical protruding portion 23 is passed through the insertion hole 16, and the cylindrical protruding portion 23 is moved outward from the vertical surface portion 31 in the axial direction (left-right direction). A projecting step is performed. In this step, as shown in FIG. 18 (a), the step rail member 4A is positioned between the left and right columns 3, and the cylindrical protrusions 23 on both ends of the column member 4A are arranged from the inside of the column 3 to the vertical surface portion 31. The pair of struts 3 and the tread bar member 4A are set in a predetermined support state by being inserted through the insertion holes 16 formed in the above. In the state where the pair of support columns 3 and the footpiece member 4A are set in this way, most of the cylindrical protrusions 23 protrude outward from the vertical surface portions 31 of the left and right support posts 3, and The first clamping surface 21 is in contact with or substantially in contact with the inner support surface 31 x of the vertical surface portion 31. Moreover, the support | pillar 3 and the crosspiece member 4A will be in the state fixedly supported by the predetermined type | mold etc. in the set state.

  Then, the protruding portion of the cylindrical protruding portion 23 is compressed and deformed with respect to the pair of struts 3 and the crosspiece member 4A set as described above to form a flange portion 15 as a sandwiching portion, and A step of caulking and fixing the crosspiece member 4A to the column 3 is performed. In this step, as shown in FIGS. 17 and 18, a pair of pressing dies that press the cylindrical projecting portion 23 projecting from the insertion hole 16 of the support column 3 along the cylindrical axis direction on both ends of the tread bar member 4A. Punch 40 is used.

  Here, the punch 40 used with the manufacturing method of the foot fixing structure of this embodiment is demonstrated using FIG. The punch 40 has a substantially cylindrical outer shape as a whole, and includes an insertion portion 41 that constitutes a portion on the distal end side in the pressing direction of the punch 40, a pressing portion 42 that is a diameter-expanded portion with respect to the insertion portion 41, A proximal end portion 43 that constitutes a portion on the rear end side of the pressing portion 42. The insertion part 41, the pressing part 42, and the base end part 43 are provided concentrically with each other.

  The insertion portion 41 is a portion having a cylindrical outer shape, and in the cylindrical core portion 24 (inside the cylindrical protruding portion 23) of the stepping bar member 4 </ b> A in the process of press molding with respect to the column 3 and the stepping bar member 4 </ b> A. It becomes a part to be inserted into. That is, the punch 40 functions as a male mold that inserts the insertion portion 41 into the cylindrical core portion 24 of the traverse member 4A. Therefore, the insertion portion 41 has an outer diameter that is substantially the same as the inner diameter of the cylindrical core portion 24 so as to be inserted into the cylindrical core portion 24. Moreover, the insertion part 41 has the taper part 41a which is gradually diameter-reduced toward the front end side at the front-end | tip part of a press direction. Insertion of the insertion portion 41 into the cylindrical core portion 24 is guided by the taper portion 41a. In addition, since a pair of plane part 23m is formed in the cylindrical protrusion part 23, the insertion part 41 inserted in the cylindrical protrusion part 23 is the cylindrical protrusion part 23 which has the plane part 23m, for example. It may have a cross-sectional shape corresponding to the inner peripheral shape.

  The pressing portion 42 is an annular plate-like portion protruding outward in the radial direction so as to form a bowl-shaped portion in the punch 40. That is, the insertion portion 41 protrudes from one plate surface side of the pressing portion 42. The annular plate surface of the pressing portion 42 on the side from which the insertion portion 41 protrudes becomes a pressing surface 42 a that contacts the opening end of the cylindrical protruding portion 23 and presses against the cylindrical protruding portion 23. The pressing surface 42 a is a surface perpendicular to the cylinder axis direction (center axis direction) of the punch 40.

  The base end portion 43 is a portion having a cylindrical outer shape, and is configured to protrude from a surface opposite to the pressing surface 42 a of the pressing portion 42. In the present embodiment, the base end portion 43 has an outer diameter that is smaller than the outer diameter of the insertion portion 41. The base end portion 43 is a portion that fixes the punch 40 to a movable portion in a predetermined molding machine via an attachment plate or the like. That is, the punch 40 is supported and fixed to the movable portion by the base end portion 43 in a predetermined molding machine, and is provided so as to reciprocate along the cylinder axis direction (center axis direction).

  The punch 40 as described above is used, and a processing step is performed in which the flange portion 15 is formed by compressive deformation of the cylindrical projecting portion 23 and caulking and fixing between the traverse member 4A and the support column 3 are performed. Such a processing step can be said to be the following step. That is, with the punch 40 having the pressing surface 42 a that contacts the end surface 23 a of the cylindrical projecting portion 23 in a state where the first clamping surface 21 of the tread bar member 4 A is in contact with the inner support surface 31 x of the vertical surface portion 31 of the column 3. By pressing the cylindrical projecting portion 23 in a direction opposite to the projecting direction from the first sandwiching surface 21, the second sandwiching is opposed to the first sandwiching surface 21 and contacts the outer support surface 31y of the vertical surface portion 31. In this step, the flange portion 15 that forms the surface 22 is bent and the vertical surface portion 31 is pressed between the flange portion 15 and the main body portion 14. A processing process using such a punch 40 will be described in detail.

  As shown in FIGS. 17 and 18 (a), the punch 40 is set to the left and right outer sides, that is, from the left and right struts 3 in the left-right direction with respect to the pair of struts 3 and the footpiece member 4A set as described above. It is arrange | positioned in the left-right outer side rather than the cylindrical protrusion part 23 which protruded outside. Each punch 40 is arranged so that the taper portion 41a side faces the opening end of the cylindrical protrusion 23 and the central axis coincides with the position of the central axis (of the cylindrical core portion 24) of the traverse member 4A. Is done.

  From such an arrangement, as shown in FIG. 18 (a), linearly along the central axis direction so that each punch 40 approaches the cylindrical projection 23, that is, the punches 40 on both sides approach each other. (See arrow F1). As for the direction of movement along the central axis direction of the punch 40, the direction approaching the cylindrical protrusion 23 (see arrow F1), that is, the direction of pressing the cylindrical protrusion 23 along the central axis direction is forward, The opposite is considered backward.

  As the punch 40 moves forward, the punch 40 inserts the insertion portion 41 into the cylindrical projection 23 from the distal end side (tapered portion 41a side), and the pressing surface 42a of the pressing portion 42 is inserted into the cylindrical projection 23. Is brought into contact with the end face 23a. From this state, when the punch 40 further moves forward (see arrow F2), the cylindrical protrusion 23 is bent and deformed.

  Specifically, as shown in FIG. 18B, the cylindrical projecting portion 23 is compressed in the central axis direction by being pressed by the punch 40 and having a substantially central position in the central axis direction as a bending position. At the same time, it is deformed so as to expand in diameter, that is, to bend radially outward (see arrow G1). That is, the cylindrical projecting portion 23 is bent and deformed so as to have a mountain shape with a substantially central position in the central axis direction as a ridge line portion and a radially outer side as a top side in a longitudinal sectional view. Therefore, as shown in FIGS. 18B and 19A, in the cylindrical projecting portion 23 in the process of pressing deformation by the punch 40, as described above, the outer side in the radial direction is the top side in the longitudinal sectional view. A base-side slope portion 23c and a tip-side slope portion 23d having a mountain shape are temporarily formed.

  Further, the cylindrical projecting portion 23 is compressed and caulked in the direction of the central axis by the pressing action accompanying the further advancement of the punch 40, and the support column 3 in a state where the proximal-side inclined surface portion 23c and the distal-end-side inclined surface portion 23d are folded on each other. It will be in the state press-contacted to the vertical surface part 31 of this. In such a state, the base-side inclined surface portion 23c is pressed from the left and right outer sides to the vertical surface portion 31 in which the inner support surface 31x which is the left and right inner surface is pressed against the first clamping surface 21 of the main body portion 14 of the crosspiece 4. It will be in the state.

  That is, as shown in FIGS. 18 (c) and 19 (b), the proximal-side inclined surface portion 23 c in the deformation process of the cylindrical protrusion 23 finally holds the vertical surface portion 31 in the flange portion 15. The inner annular portion 15 c that forms the clamping surface 22, and the distal-side inclined portion 23 d that is located on the left and right outer sides of the proximal-side inclined portion 23 c becomes the outer annular portion 15 d of the flange portion 15. In this way, the flange portion 15 of the step rail 4 is formed, and the vertical surface portion 31 of the column 3 is pressed and clamped by the main body portion 14 and the flange portion 15, that is, the step having the main body portion 14 and the flange portion 15. The crosspiece 4 is formed, and the support post 3 and the treadle 4 are fixed to each other.

  The manufacturing method of the step-bar fixing structure of the present embodiment as described above is performed in the vertical portion 3a of the column 3 in the same manner as in the inclined portion 3b. Specifically, in the case of the inclined portion 3b, the point where the step rail 4 is fixed to the column 3 is the vertical surface portion 31. In the case of the vertical portion 3a, the insertion hole 16 in the upper side wall portion 11a of the column 3 is used. This is the part where is formed. The method for manufacturing the foot fixing structure in the vertical portion 3a of the column 3 will be described with reference to FIGS. 19 and 20 with the portions common to the inclined portion 3b omitted as appropriate.

  After the support column 3 and the footpiece member 4A are prepared as described above, the cylindrical protruding portion 23 is passed through the insertion hole 16, and the cylindrical protruding portion 23 protrudes outward from the upper side wall portion 11a in the axial direction (left-right direction). The process of making is performed. In this step, as shown in FIG. 20 (a), the step rail member 4A is positioned between the left and right support columns 3, and the cylindrical protrusions 23 on both ends of the step beam member 4A are connected to the upper side wall portion from the inner side of the support column 3. It is inserted into the insertion hole 16 formed in 11a, and the pair of support columns 3 and the tread bar member 4A are set in a predetermined support state. Thus, in the state in which the pair of support columns 3 and the traverse member 4A are set, most of the cylindrical protruding portion 23 protrudes outward from the upper side wall portions 11a of the left and right support columns 3, and the traverse member 4A. The first clamping surface 21 is in contact with or substantially in contact with the inner support surface 11x of the upper side wall portion 11a.

  And the punch 40 is used and the process process which performs the caulking fixation of 4 A of stepping bar members 4A and the support | pillar 3 accompanying the formation of the collar part 15 by the compression deformation of the cylindrical protrusion part 23 is performed. That is, in the case of the vertical portion 3 a, the pressure that contacts the end surface 23 a of the cylindrical projecting portion 23 in a state where the first clamping surface 21 of the traverse member 4 A is in contact with the inner support surface 11 x of the upper side wall portion 11 a of the column 3. The punch 40 having the surface 42a presses the cylindrical projecting portion 23 in a direction opposite to the projecting direction from the first clamping surface 21, thereby opposing the first clamping surface 21 and supporting the outer side wall portion 11a on the outside. The flange 15 that forms the second clamping surface 22 that contacts the surface 11 y is bent and the upper side wall 11 a (the portion where the insertion hole 16 is formed) is pressed and clamped by the flange 15 and the main body 14. A process is performed.

  As shown in FIG. 20 (a), the punch 40 moves forward from the state in which the punches 40 are arranged on the left and right outer sides with respect to the pair of support columns 3 and the footpiece member 4A set as described above. (See arrow H1). The punch 40 is inserted into the cylindrical projecting portion 23 from the distal end side (tapered portion 41a side) by the forward movement, and the pressing surface 42a is brought into contact with the end surface 23a of the cylindrical projecting portion 23. The cylindrical protrusion 23 is pressed and deformed by bending (see arrow H2 and arrow J1).

  Then, as shown in FIGS. 19 (a) and 20 (b), in the process of pressing deformation by the punch 40, a proximal-side inclined surface portion 23c and a distal-end-side inclined surface portion 23d are temporarily formed in the cylindrical projecting portion 23. Finally, as shown in FIGS. 19B and 20C, the cylindrical projecting portion 23 is compressed and caulked in the direction of the central axis, and the proximal-side slope portion 23c and the distal-side slope portion 23d are Are in a state of being in pressure contact with the upper side wall portion 11a of the support column 3 in a state of being folded on each other. In such a state, the base-side inclined surface portion 23c is formed from the left and right outer sides with respect to the upper side wall portion 11a in which the inner support surface 11x which is the left and right inner surface is pressed against the first clamping surface 21 of the main body portion 14 of the step rail 4. It will be in the state of pressure contact.

  That is, the base end side slope portion 23c finally becomes the inner annular portion 15c that forms the second clamping surface 22 that sandwiches the upper side wall portion 11a in the flange portion 15, and is located on the left and right outer sides of the base end side slope portion 23c. The tip side inclined surface portion 23 d becomes the outer annular portion 15 d of the flange portion 15. In this way, the collar portion 15 of the traverse 4 is formed, and the inner support surface 11x of the column 3 is pressed and clamped by the main body portion 14 and the collar portion 15, that is, the main body portion 14 and the collar portion 15 are provided. The step rail 4 is formed, and the column 3 and the step rail 4 are fixed to each other.

  As described above, the crosspiece fixing structure of the present embodiment is manufactured in each of the vertical portion 3a and the inclined portion 3b of the column 3. In the present embodiment, in the caulking process using the punch 40, the two punches 40 located on both the left and right sides of the pair of support columns 3 and the footpiece member 4A are caulked (right and left symmetrically) (press molding). However, the caulking process by the punch 40 may be performed at the timing when the left and right are different from each other, that is, the left and right sides.

  According to the foot fixing structure and the manufacturing method thereof according to the present embodiment described above, the structure in which the support column 3 includes the inclined portion 3b that is the portion inclined with respect to the direction perpendicular to the axial direction of the foot rail 4 is simple. With this simple structure, the step rail 4 can be securely fixed to the support column 3 and the productivity can be improved.

  In the configuration having the inclined portion 3b so as to spread downward, like the pair of support columns 3 constituting the ladder body 2 in the stepladder 1 of the present embodiment, the inclined step 3 is not perpendicular to the axial direction of the tram 4 It is difficult to realize a fixing structure in which the lower side wall portion 11b itself serving as a surface portion is an object to be clamped by a hook-shaped portion formed at the end portion of the traverse 4. Therefore, the footboard fixing structure according to the present embodiment is a support that is perpendicular to the axial direction (longitudinal direction) of the footrail 4 as a portion where the end of the footrail 4 is fixed to the inclined portion 3b of the column 3. While the vertical surface portions 31 that form the surfaces (the inner support surface 31x and the outer support surface 31y) on both the inner and outer sides of the support column 3 are provided, the tread bar 4 has the first clamping surface 21 that contacts the inner support surface 31x as the left and right end surfaces. The main body 14 and the flange 15 that is provided outside the main body 14 via the vertical surface 31 and forms the second clamping surface 22. The vertical surface 31 is formed by the main body 14 and the flange 15. Uses a structure that clamps and presses.

  With such a configuration, the number of parts and the number of man-hours in the manufacturing process can be reduced with respect to the fixing of the pedestal to the column, compared to the conventional structure using fixing members such as rivets and screws, and welding / bonding. The configuration can be realized and the productivity can be improved. Further, since the plate portion sandwiched by the step rail 4 on the column 3 side becomes a surface portion perpendicular to the axial direction of the column 4, the support surface on the column 3 side and the clamping surface on the step rail 4 side are entirely covered. Therefore, as the press-clamping state of the support column 3 by the first clamping surface 21 and the second clamping surface 22 of the tread bar 4, a reliable and stable fixed state can be obtained. As a result, high safety can be obtained in the ladder body 2 constituting the stepladder 1.

  In addition, the step rail fixing structure and the method of manufacturing the same according to the present embodiment are configured so that the vertical portion, which is a portion that forms a support surface perpendicular to the axial direction of the step rail 4 in the erected state, is sandwiched between the step rails 4. Since it is an object to be clamped by the surface, a common structure can be adopted as to the structure on the side of the tram 4 as long as it has a part corresponding to the vertical part in the column 3 and a common manufacturing method. Can be adopted. In the present embodiment, the column 3 has an upper side wall portion 11a corresponding to the vertical portion in the vertical portion 3a, and a vertical surface portion 31 that is a vertical portion in the inclined portion 3b. The same fixing structure and the manufacturing method thereof can be applied to all the traversing bars 4 constituting the. Thus, according to the foot fixing structure and the manufacturing method thereof according to the present embodiment, in the configuration in which the pair of support columns 3 have the vertical portion 3a and the inclined portion 3b, for example, like the ladder body 2 according to the present embodiment, Even if it is a straight ladder part or a ladder part where the width between the support columns 3 changes, it is possible to cope with the fixing structure of the crossing and the manufacturing method in one pattern, so that high versatility can be obtained. it can.

  In addition, according to the step rail fixing structure and the manufacturing method thereof according to the present embodiment, the side wall portion of the column 3 is clamped together with the flanges 15 positioned on the left and right outer sides of the column 3 at the fixing portion of the column 4 to the column 3. As a part, it is not necessary to previously form a hook-like part positioned on the left and right inner sides of the column 3 as in the prior art. For this reason, it is possible to simplify the step of forming the crosspiece member 4A for constituting the crosspiece fixing structure, and to improve productivity.

  Further, in the step-bar fixing structure of the present embodiment, the cylindrical protruding portion 23 protruding from the first holding surface 21 is inserted as a holding portion for holding the vertical surface portion 31 or the upper side wall portion 11a together with the main body portion 14 of the step-piece 4. It has a configuration that employs the flange portion 15 formed by being compressed and deformed in a state of passing through the hole 16. According to such a configuration, the holding portion that holds the vertical surface portion of the column 3 together with the main body portion 14 can be easily formed by, for example, compression molding using the punch 40 as described above, and the holding portion can be formed. At the same time, since the crosspiece 4 can be caulked and fixed to the support column 3 by the main body portion 14 and the flange portion 15, a surely fixed state can be obtained. As a result, while the productivity can be improved, the step rail 4 can be securely fixed to the column 3.

  Moreover, according to the manufacturing method of the foot fixing structure according to the present embodiment, as described above, the holding portion that holds the vertical surface portion of the column 3 together with the main body portion 14 can be easily formed by compression molding using the punch 40. Therefore, it is possible to easily realize the automation of the manufacturing process of the crosspiece fixing structure.

  In addition, the step rail fixing structure of the present embodiment includes a hollow cylindrical core portion 24 that has an annular shape in cross section and has a cylindrical protrusion portion 23 formed by both end portions in the axial direction. A configuration having a tread surface forming portion 25 that is provided outside the core portion 24 and forms a flat tread surface 25s is employed. According to such a configuration, the tread 25 s can be provided with a high degree of freedom without being limited by the shape of the portion inserted into the insertion hole 16 of the support column 3 in the tread bar 4.

  For example, in the case where the crosspiece 4 is configured by a linear molded part having a cross-sectional shape of the portion inserted into the insertion hole 16 as a whole in a common cross-sectional shape, that is, in this embodiment, the cylindrical core portion 24 is formed. In order to increase the tread surface, it is necessary to enlarge the entire tread member including the portion inserted into the insertion hole 16, and therefore it is necessary to increase the hole diameter of the insertion hole 16. Arise. However, increasing the hole diameter of the insertion hole 16 causes a decrease in strength of the support column 3 as a molded part.

  Therefore, as described above, according to the configuration including the cylindrical core portion 24 and the tread surface forming portion 25 in the step rail 4, the insertion portion of the column 3 in the insertion hole 16 in the step rail 4 is the cylindrical core portion 24. Therefore, the tread surface forming portion 25 that is a portion located between the left and right cylindrical protruding portions 23 and is an overhang portion with respect to the cylindrical core portion 24 is inserted into the insertion hole. It is possible to design with a relatively high degree of freedom without being restricted by the 16 shapes. Accordingly, since the insertion hole 16 can have a hole diameter corresponding to the size of the cylindrical protrusion 23, a sufficiently wide tread 25s is provided without making the insertion hole 16 larger than necessary. be able to. In other words, the tread surface 25s can be widened to some extent with respect to the size of the hole diameter of the insertion hole 16, so that the strength of the column 3 can be secured and the stability and safety when the stepladder 1 is used. Can be improved easily.

  Further, in the step rail fixing structure of the present embodiment, the cylindrical protrusion 23 of the step rail 4 removes the portion of the tread surface forming portion 25 at both ends of the step rail 4 (step rail member 4A) to form a cylindrical core. It is configured to be formed by exposing the portion 24. In this regard, in the manufacturing method of the foot fixing structure, the step of preparing the foot member 4A includes the step of preparing a linear molded part having the cylindrical core portion 24 and the tread surface forming portion 25, and And a step of exposing the cylindrical core portion 24 by removing portions of the tread surface forming portion 25 at both end portions to form the cylindrical projecting portion 23.

  According to such a configuration, the step surface forming portion 25 at both ends of the crosspiece member 4A is cut away by cutting or the like, so that the end surface from which the tread surface forming portion 25 is cut, that is, the step surface from which the cylindrical protruding portion 23 protrudes. It becomes possible to make the 1st clamping surface 21 used as a surface perpendicular | vertical with respect to the axial direction of the footrail 4 reliably.

  In this regard, for example, as a method of forming the cylindrical protrusion 23, it is conceivable to form a small-diameter portion by drawing at both ends of the extruded product as the cylindrical protrusion 23. The step portion between the small-diameter portion and the large-diameter portion, which is a non-machined portion, tends to be tapered, making it difficult to make the step surface perpendicular to the axial direction. When the stepped surface that is the clamping surface is not vertical, in the configuration in which the step rail 4 is fixed to the column 3 by pressing and clamping the plate-like portion of the column 3 such as the vertical surface portion 31, a sufficient clamping operation cannot be obtained and fixed. May be insufficient.

  Therefore, in the configuration having the cylindrical core portion 24 and the tread surface forming portion 25 as in the present embodiment, a method of forming the cylindrical projecting portion 23 by cutting off the tread surface forming portions 25 at both ends of the crosspiece member 4A. According to this, the first clamping surface 21 as the step surface can be easily and surely made a vertical surface by cutting the cylindrical core portion 24. Thereby, the support surface in the support | pillar 3 and the clamping surface in the tread bar 4 can be made to surface-contact reliably completely, sufficient clamping effect | action can be obtained and a reliable fixed state can be obtained.

  In addition, the crosspiece fixing structure of the present embodiment is a hollow portion having a cross-sectional shape and an outer shape along a substantially triangular shape with respect to the tread surface forming portion 25, and a main surface portion that is a side portion in the cross-sectional shape. The structure which forms the tread 25s by 25a is employ | adopted. According to such a configuration, it is possible to easily secure a large area for the tread surface 25s, and it is possible to obtain a high strength with respect to the tread bar 4 in relation to the cylindrical core portion 24, and the hollow portion. Can achieve weight reduction. However, as described above, the shape of the tread surface forming portion 25 is not particularly limited as long as it is a predetermined shape portion that forms the tread surface 25 s on the outer peripheral side of the cylindrical core portion 24.

  Here, regarding the shape and the like of the tread surface forming portion 25, another configuration example of the tread bar 4 (the tread bar member 4 </ b> A) will be described with reference to FIGS. 21 and 22. As shown in FIGS. 21 and 22, in this configuration example, the tread surface forming portion 25 </ b> X that is provided substantially symmetrically in the vertical direction and forms the planar tread surface 25 s is a pair of extending plates that extend from the cylindrical core portion 24. It is comprised by the parts 25d and 25e.

  The pair of extending plate portions 25d and 25e has a cylindrical core portion 24 in a cross-sectional shape within a range longer than the outer diameter of the cylindrical core portion 24 with respect to the substantially annular cylindrical core portion 24. Are extended in a straight line from the end of each of the two ends along tangents in opposite directions. The pair of extending plate portions 25 d and 25 e extend from positions spaced from each other at a predetermined interval at the end of the cylindrical core portion 24. The pair of extending plate portions 25 d and 25 e are provided as strip-like portions along the longitudinal direction of the step rail 4 so as to form a common cross-sectional shape in the main body portion 14 of the step rail 4.

  The tread surface 25s formed by the pair of extending plate portions 25d and 25e in each of the upper and lower tread surface forming portions 25X is predetermined as in the case of the tread surface forming portion 25 (see FIGS. 10A and 10B). Inclined in the direction of That is, in the configuration in which the pair of tread surface forming portions 25X is provided symmetrically in the vertical direction, the interval between the integral plate-like portions formed by the pair of extending plate portions 25d and 25e in the upper and lower tread surface forming portions 25X is the ladder. The climbing surface side (the right side in FIGS. 21A and 21B) of the body 2 is narrow and the anti-climbing surface side (the left side in FIG. 21) is wide.

  Further, in each of the extended plate portions 25d and 25e constituting the tread surface forming portion 25X, the extended plate portions 25d and 25b that are linear in the cross-sectional shape are provided at the ends on the protruding side from the cylindrical core portion 24. An anti-slip portion 25f is provided which has a substantially circular shape with respect to the main body portion 25e. The anti-slip portion 25 f is provided as a linear portion along the longitudinal direction of the traverse 4 at the edge on the protruding side from the cylindrical core portion 24 in each of the extension plate portions 25 d and 25 e.

  Further, in this configuration example, a reinforcing protrusion 24 a is provided on the outer peripheral side of the cylindrical core portion 24. The protruding portion 24 a is a portion that has a cross-sectional shape and protrudes from the outer peripheral surface of the cylindrical core portion 24 in a substantially semicircular shape, and is provided as a linear portion along the longitudinal direction of the traverse 4. In the example shown in FIGS. 21A and 21B, a base portion 25g with respect to the cylindrical core portion 24 of the extension plate portion 25d is provided between the upper and lower extension plate portions 25d having a relatively large distance between each other. , Four protrusions 24 a are provided at substantially equal intervals in the circumferential direction of the cylindrical core 24. In addition, between the upper and lower extension plate portions 25e having a relatively narrow distance between each other, the circumference of the cylindrical core portion 24 is related to the base portion 25g with respect to the cylindrical core portion 24 of the extension plate portion 25e. Two protruding portions 24a are provided at substantially equal intervals in the direction. The base portions 25g of the extended plate portions 25d and 25e are portions that have a wide base shape with respect to the main body portions of the extended plate portions 25d and 25e that are linear in cross section.

  In such a configuration example, the tread surface forming portion 25 </ b> X is a portion that constitutes an overhanging portion that protrudes outward with respect to the cylindrical core portion 24 when viewed in the cylinder axis direction, and is cylindrical at both end portions of the tread bar 4. A stepped portion is formed with respect to the protruding portion 23, and the stepped surface is defined as a first clamping surface 21 that is perpendicular to the axial direction of the traverse 4. According to this configuration example, in comparison with a configuration in which the tread surface forming portion 25 is provided as a hollow portion having a cross-sectional shape and having an outer shape along a substantially triangular shape (see FIGS. 10A and 10B), Since the shape of the forming portion 25X becomes simple, the weight can be reduced, and the strength of the tram 4 can be secured by the protruding portion 24a.

  In addition, the step rail fixing structure of the present embodiment employs a configuration having a shape in which relative rotation is restricted as an insertion shape of the cylindrical protrusion 23 and the insertion hole 16. According to such a configuration, it is possible to reliably prevent the tread bar 4 from rotating in a fixed state between the pair of support columns 3 with a simple structure. Accordingly, the position of the tread surface 25s formed by the tread surface forming portion 25 can be reliably held at a predetermined position, so that the positioning property of the tread surface 25s at the time of manufacturing the stepladder 1 can be improved, and the stepladder 1 The stability and safety during use can be improved. However, as described above, the insertion shapes of the cylindrical protrusion 23 and the insertion hole 16 are not particularly limited.

  Here, the other structural example of the insertion shape of the cylindrical protrusion part 23 and the insertion hole 16 is demonstrated using FIG. In the example shown in FIG. 23A, a portion that is linear in the circumferential shape in a cross-sectional view is provided only on the climbing surface side (right side in the drawing). That is, in the example shown in FIG. 23 (a), the insertion hole 16 has a straight portion 16m at a position on the climbing surface side in the inner peripheral portion having a substantially circular hole shape. The substantially circular outer shape has a straight portion 15m at a predetermined position on the climbing surface side. In the case of this configuration as well, the planar portion 23m is formed at a position corresponding to the straight portion 15m in the cylindrical protruding portion 23. Further, FIG. 23 illustrates a configuration having the tread surface forming portion 25X including the extending plate portions 25d and 25e as described above as a portion for forming the tread surface 25s.

  In the example shown in FIG. 23 (b), the straight portion provided only on the climbing surface side (the right side in the drawing), that is, the straight portion 16m of the insertion hole 16 and the straight portion 15m of the cylindrical portion 15b are in a cross-sectional shape. It is provided along the direction perpendicular to the tread 25s along the straight line. 23 (a) and 23 (b) show a configuration in which the straight line portion in the insertion shape is provided only on the climbing surface side, the same straight line portion is provided only on the anti-climbing surface side (left side in the figure). The structure provided in may be sufficient.

  In the example shown in FIG. 23C, the cylindrical protrusion 23 and the insertion hole 16 are inserted into a shape in which a pair of linear portions parallel to each other are formed at positions facing each other in the circumferential shape. The straight portion has a shape provided so as to be along a direction perpendicular to the tread surface 25s along the straight line in the cross-sectional shape. That is, in the example shown in FIG. 23C, the pair of straight portions 16m of the insertion hole 16 and the pair of straight portions 15m of the tubular portion 15b are both perpendicular to the tread 25s along the straight line in the cross-sectional shape. It is provided along the direction. Even in the case of these configurations, the planar portion 23m is formed at a position corresponding to the straight portion 15m in the cylindrical protruding portion 23.

  Also by the fitting shape of the cylindrical protrusion 23 and the insertion hole 16 as described above, the tread bar 4 is reliably prevented from rotating in a fixed state between the pair of columns 3 with a simple structure. Since the position of the tread surface 25s of the tread surface forming portion 25 can be reliably held at a predetermined position, the positioning property of the tread surface 25s can be improved when the stepladder 1 is manufactured, and the stability when the stepladder 1 is used can be improved. Can improve safety and safety.

  In the step-bar fixing structure and the manufacturing method thereof according to the present embodiment described above, the column 3 constituting the ladder body 2 of the stepladder 1 includes the vertical portion 3a and the inclined portion 3b, and partially includes the inclined portion 3b. Although it is a thing of a structure, as the support | pillar 3 which erected the step pedestal 4, it is slanted with respect to the direction perpendicular to the axial direction of the step pedestal 4 as a whole, that is, the structure in which the ladder body 2 is generally spread downward. It may be. In other words, the support column 3 may be configured to have at least a part of an inclined portion that is inclined with respect to a direction perpendicular to the axial direction of the traverse 4.

  Further, the support column 3 according to the present embodiment has a “U” -shaped cross-sectional shape by the side wall portion 11 and the end wall portion 12, and the open side of the “U” shape is directed to the left and right outer sides. Although it is a thing of a structure, as the support | pillar 3, the thing of the structure which orient | assigned the open side of the cross-sectional shape of a "U" shape toward the left-right inside may be sufficient. In this case, the joint fitting 6 has, for example, the fixing portion 6a as the outer side (outside in the left-right direction) of the side wall portion 11 of the support column 3, that is, the open side in the “U” shape of the cross-sectional shape of the support column 3. In a state along the surface on the opposite side, it is fixed to the column 3 by a plurality of fixing members such as rivets.

  Further, the stepladder 1 according to the present embodiment is configured to include a plurality of (six) step bars 4 in the ladder body 2, but the step bars 4 may be single. Moreover, in this embodiment, in the support | pillar 3, the part (upper side wall part 11a and the vertical surface part 31) which forms the support surface which contacts the 1st clamping surface 21 and the 2nd clamping surface 22 is a plate-shaped part. The shape is not particularly limited as long as it is a portion that forms a support surface perpendicular to the axial direction of the traverse 4.

  Moreover, although the support | pillar 3 which concerns on this embodiment has the perpendicular | vertical part used as the clamping part by the 1st clamping surface 21 and the 2nd clamping surface 22 in the inclination part 3b as the vertical surface part 31 which is a part of molded components, The vertical portion serving as the sandwiching portion may be constituted by a part different from the molded part constituting the support column 3. That is, for example, a component having a vertical plate-like portion corresponding to the vertical surface portion 31 is prepared as a separate component from the main body of the column 3 as a molded component, and this component is fixed to the main body of the column 3. Thereby, you may comprise the perpendicular | vertical part in the inclination part 3b. An example of such a configuration will be described with reference to FIGS. 24 and 25 as another embodiment of the foot fixing structure according to the present invention. In addition, the same code | symbol is used about the part which is common in embodiment mentioned above.

  As shown in FIG. 24 and FIG. 25, in the step rail fixing structure of the present embodiment, on the left and right inner sides of the inclined portion 3 b of the column 3, as in the upper side wall portion 11 a and the vertical surface portion 31, An attachment metal 50 constituting a plate-like portion (vertical portion) perpendicular to the surface is attached. That is, the attachment 50 is a separate part from the main body of the support column 3 as a molded part, and constitutes a vertical portion by being fixed to the main body of the support column 3. As described above, in the step-bar fixing structure of the present embodiment, the step-bar 4 is fixed to the left and right columns 3 via the attachment metal 50.

  The attachment metal 50 is attached to the main body of the support column 3 with the inner (left and right inner) surface between the pair of support columns 3 as an attachment surface 11 c in the lower side wall portion 11 b of the inclined portion 3 b of the support column 3. The attachment metal 50 includes a vertical surface portion 51 as a vertical portion that forms a support surface that is perpendicular to the axial direction of the standing rail 4 in the erected state, as a portion to which the end of the rail 4 is fixed. That is, in the crosspiece fixing structure of the present embodiment, the vertical surface portion 51 is the first clamping surface formed by the main body portion 14 in the crosspiece 4 like the upper side wall portion 11a and the vertical surface portion 31 in the above-described embodiment. 21 and the second clamping surface 22 formed by the flange 15 are portions that are pressed and clamped. Accordingly, the vertical surface portion 51 is a portion in which the insertion holes 56 through which the left and right end portions of the traverse 4 pass are formed, and the vertical of the attachment metal 50 attached to each of the columns 3 between the pair of columns 3. The surface portion 51 is a surface portion parallel to each other.

  Specifically, the attachment 50 has a main body 52 formed in a box shape or a bowl shape, and a flange-shaped flange 53 formed around the opening edge of the main body 52. In the mounting bracket 50, a vertical surface portion 51 is formed by a portion corresponding to the bottom plate portion of the main body portion 52.

  The attachment metal 50 is a part formed by pressing a plate-like metal member by press working such as embossing. As for the processing for forming the attachment metal 50, the cylindrical protrusion 23 of the footpiece member 4A penetrates in the press work for forming each part of the attachment metal 50 such as the main body 52 and the flange 53. You may perform the drilling process for forming the insertion hole 56 simultaneously.

  The attachment metal 50 is fixed to the attachment surface 11c of the lower side wall portion 11b of the support column 3, thereby forming a vertical surface portion 51 on the left and right inner sides of the lower side wall portion 11b. As shown in FIG. 24, the attachment metal 50 is a substantially right-angled triangle having a lower side wall part 11 b on the column 3 side and a lower side wall part 11 b as an oblique side part by a main body part 52 forming a vertical surface part 51 in a front sectional view. Make a shape. That is, with respect to the depth of the main body portion 52, the attachment metal 50 has a shape that is shallower on the upper side and deeper on the lower side when fixed to the lower side wall portion 11 b, and is perpendicular to the vertical surface portion 51. The lower side surface portion 52a formed substantially vertically from the lower end portion of the surface portion 51 forms a substantially right triangle with the lower side wall portion 11b. For this reason, the side part 52b on the upper side of the main body part 52 makes the dimension in the depth direction (left and right direction in FIG. 24) of the main body part 52 shorter than the side part 52a on the lower side.

  The flange portion 53 is perpendicular to the axial direction of the step rail 4 by the bottom portion of the main body portion 52 in a state where the attachment metal 50 is fixed to the lower side wall portion 11 b inclined with respect to the direction perpendicular to the axial direction of the step rail 4. It is formed along the inclination of the lower side wall portion 11b so that a vertical surface portion 51 is formed. That is, the flange portion 53 is a flange-like plate-like portion formed along the inclination of the lower side wall portion 11b in accordance with the relationship between the vertical surface portion 51 and the lower side wall portion 11b. The plate surface 53a opposite to the side from which the main body portion 52 of the portion 53 protrudes is attached to the lower side wall portion 11b in a state where the plate surface 53a is in full contact with the mounting surface 11c of the lower side wall portion 11b.

  The attachment metal 50 is fixed to the lower side wall portion 11b by a portion of the flange portion 53 that overlaps the lower side wall portion 11b. Specifically, for example, as shown in FIGS. 24 and 25, the fixing hole 11 d formed in each of the lower sidewall portion 11 b and the flange portion 53 in a portion where the lower sidewall portion 11 b and the flange portion 53 overlap each other. , 53d, and the attachment metal 50 is fixed to the lower side wall portion 11b by the rivet 55. Fixing portions by rivets 55 are provided at a plurality of locations as appropriate. The fixing member for fixing the attachment metal 50 to the lower side wall portion 11b is not limited to the rivet 55, and screws, bolts, nuts, and the like are appropriately employed. Moreover, welding and adhesion | attachment etc. may be used about fixation with respect to the lower side wall part 11b of the attachment metal 50. FIG.

  In such a configuration, the plate surfaces on both sides in the left-right direction of the vertical surface portion 51 formed by the attachment metal 50 serve as support surfaces for the footrail 4. That is, the vertical surface portion 51 serves as a support surface that is perpendicular to the axial direction of the traverse 4 and has an inner support surface 51x that is an inner support surface between the pair of support columns 3 and an outer support surface 51y that is an outer support surface. And have.

  As with the vertical surface portion 31, the vertical surface portion 51 is provided so as to have a size including at least a portion sandwiched between the first clamping surface 21 and the second clamping surface 22 as a portion where the insertion hole 56 is formed. . Note that the insertion hole 56 does not rotate relative to the support column 3 of the tram 4 in the axial direction in the relationship with the cylindrical protrusion 23 as in the insertion hole 16 formed in the vertical surface portion 31 in the above-described embodiment. It has a controlled insertion shape.

  As described above, the footboard fixing structure of the present embodiment has the vertical surface portion 51 formed by the mounting metal 50 attached to the lower side wall portion 11b in the inclined portion 3b of the column 3, and the vertical surface portion 51 is the above-described implementation. Similar to the vertical surface portion 31 in the form, it becomes a portion that is pressed and clamped by the main body portion 14 and the flange portion 15 of the stepping rail 4, and the end portion in the axial direction of the stepping rail 4 is fixedly supported to the column 3 via the attachment metal 50. The That is, in the crosspiece fixing structure of the present embodiment, the first clamping surface 21 formed by the main body portion 14 of the crosspiece 4 is in contact with the inner support surface 51x of the vertical surface portion 51 and is formed by the flange portion 15. The second clamping surface 22 is in contact with the outer support surface 51y of the vertical surface portion 51, and the vertical surface portion 51 is sandwiched from both the left and right sides by the first clamping surface 21 and the second clamping surface 22 facing each other.

  Therefore, in the footrail fixing structure of the present embodiment, the main body portion 14 serves as the first sandwiching portion that contacts the inner support surface 51x of the support surfaces of the vertical surface portion 51 as end surfaces on both sides in the axial direction of the footrail 4. Surface 21 is formed. The flange 15 forms a second clamping surface 22 that faces the first clamping surface 21 of the main body 14 and contacts the outer support surface 51 y of the support surfaces of the vertical surface 51. In other words, in the present embodiment, the flange portion 15 is a portion of the pedestrian crossing 4 in which the most part is located on the left and right outer sides of the vertical surface portion 51, that is, on the outer side in the left and right direction than the outer support surface 51 y of the vertical surface portion 51. Yes, the second clamping surface 22 is brought into contact with the outer support surface 51y.

  In the present embodiment, most of the flange portion 15 is located in the main body portion 52 of the attachment metal 50. In other words, in a state in which the crosspiece 4 is fixed to the support column 3 via the attachment metal 50, most of the flange portion 15 is located in the closed space 50a formed by the attachment metal 50 and the lower side wall part 11b. become.

  As a manufacturing method of the treadle fixing structure of the present embodiment, a step of preparing the attachment metal 50 is performed in addition to the step of preparing the support post 3 and the stepping member 4A as described above. And, by the same process as the above-described embodiment, after the attachment metal 50 is fixed to both ends of the traverse member 4A, the left and right attachment metal 50 are respectively fixed to the lower side wall part 11b of the support column 3, A pedestal 4 is configured.

  That is, first, a step is performed in which the cylindrical protruding portion 23 of the crosspiece member 4A is passed through the insertion hole 56 of the mounting bracket 50, and the cylindrical protruding portion 23 is protruded from the vertical surface portion 51 outward in the axial direction (left-right direction). Is called.

  Next, the punch 40 as described above is used, and a processing step is performed in which the flange portion 15 is formed by compressive deformation of the cylindrical projecting portion 23 and the tread bar member 4A and the support column 3 are fixed by caulking. . In such a processing step, the pressing surface 42 a that contacts the end surface 23 a of the cylindrical protrusion 23 is formed in a state where the first clamping surface 21 of the crosspiece member 4 </ b> A is in contact with the inner support surface 51 x of the vertical surface portion 51 of the mounting bracket 50. By pressing the cylindrical projecting portion 23 in a direction opposite to the projecting direction from the first sandwiching surface 21 by the punch 40 having, it faces the first sandwiching surface 21 and contacts the outer support surface 51y of the vertical surface portion 51. In this step, the flange portion 15 forming the second clamping surface 22 is bent and the vertical surface portion 51 is pressed and clamped by the flange portion 15 and the main body portion 14.

  And the attachment metal 50 fixed to the both ends of the axial direction of the footrail 4 is fixed to the lower side wall part 11b of the support | pillar 3 with the rivet 55. FIG. As described above, the end portion of the traverse 4 is fixed to the support column 3 via the attachment metal 50.

  As described above, in the structure of fixing the tram, the first clamping surface 21 and the second clamping surface 22 are pressed and clamped by the mounting member such as the mounting bracket 50 that is a separate component from the main body of the column 3. It may constitute a vertical part. According to the crosspiece fixing structure of the present embodiment, the following operations and effects can be obtained in addition to the same operations and effects as in the above-described embodiment.

  According to the step-bar fixing structure of the present embodiment, in a configuration in which a plurality of step bars 4 are installed between a pair of support columns 3, each of the other step beams 4 is maintained in a fixed state between the pair of support columns 3. It becomes possible to perform the attachment and detachment of the step rail 4 with respect to the column 3 independently. That is, in the crosspiece fixing structure of the present embodiment, each of the crosspieces 4 is fixed to the support post 3 via the attachment metal 50, so that the removal of the attachment metal 50 from the support post 3 allows the It can be removed from the column 3 and can be similarly installed. Therefore, for example, when one step rail 4 is deformed or damaged, only the step rail 4 can be easily replaced. As described above, according to the step rail fixing structure of the present embodiment, each step rail 4 can be independently replaced, so that the durability as the stepladder 1 can be improved, and the use site of the stepladder 1 can be improved. It is possible to meet a wide range of applications and customer needs.

  Note that the mounting member 50 as described above is used for the mounting member that is interposed between the crosspiece 4 and the main body of the column 3 and that constitutes the vertical portion that is pressed and clamped by the first clamping surface 21 and the second clamping surface 22. Without being limited to the above, various shapes and materials can be adopted. The mounting member is not a part having a shape that forms the closed space 50a together with the lower side wall portion 11b as in the case of the mounting metal 50. For example, the vertical surface portion 51 and the flange portion 53 appearing in a front sectional view as shown in FIG. It may be a component in which a plate-like member is simply bent so as to have a shape portion corresponding to. Further, the attachment member is not limited to a metal part such as the attachment metal 50, and may be a resin part. Further, the processing method for manufacturing the attachment metal 50 is not limited to press processing, and may be injection molding or the like.

DESCRIPTION OF SYMBOLS 1 Stepladder 2 Ladder body 3 Support | pillar 3b Inclined part 4 Treading bar 4A Treading bar member 4B Molded part for treading bar 11a Upper side wall part 14 Main body part 15 Gutter part (clamping part)
15 m linear portion 16 insertion hole 16 m linear portion 21 first clamping surface 22 second clamping surface 23 cylindrical protruding portion 23 m flat portion 24 cylindrical core portion 25 tread surface forming portion 25 a main surface portion 25 s tread surface 31 vertical surface portion (vertical portion)
31x inner support surface 31y outer support surface 40 punch (pressing type)
42a Press surface 50 Mounting metal 51 Vertical surface portion 51x Inner support surface 51y Outer support surface 56 Insertion hole

Claims (9)

A fixing structure for a traverse, comprising a pair of struts that are vertical members, and a traverse horizontally mounted between the pair of struts, the end of the traverse being fixed to the strut,
The support column has an inclined portion inclined at least in part with respect to a direction perpendicular to the axial direction of the crosspiece,
The inclined portion is a portion to which the end portion of the step rail is fixed. Including the vertical part to form,
The crosspiece has a main body portion forming a first clamping surface that contacts an inner support surface of the support surfaces as end surfaces on both sides in the axial direction, and is opposed to the first clamping surface and out of the support surfaces A structure for fixing a treadle, comprising: a second clamping surface that contacts an outer support surface; and a clamping part that press-clamps the vertical part together with the main body part. The clamping part is a bowl-shaped part formed by deforming a cylindrical projecting part, which is a part projecting cylindrically from the first clamping surface, through an insertion hole formed in the vertical part. The fixing structure for a foot cross according to claim 1, wherein: The tram is
A hollow cylindrical core that forms an annular shape in a cross-sectional shape and forms the cylindrical protrusion by both axial ends; and
The treadle fixing structure according to claim 2, further comprising: a tread surface forming portion that is provided outside the cylindrical core portion and forms a flat tread surface. 4. The step according to claim 3, wherein the cylindrical projecting portion is formed by removing portions of the tread surface forming portion at both ends of the step rail to expose the cylindrical core portion. 5. Fixed structure of the crosspiece. The said tread surface formation part is a hollow part which makes the external shape which follows a substantially triangular shape with a cross-sectional shape, and forms the said tread surface by the one side part in a cross-sectional shape. Item 5. The fixing structure of the crosspiece according to Item 4. 4. The step according to claim 2, wherein the cylindrical projecting portion and the insertion hole have an insertion shape that restricts relative rotation of the step rail with respect to the support column around the axial direction. 5. Fixed structure of the crosspiece.   A stepladder comprising the fixing structure for a foot cross according to any one of claims 1 to 6. A manufacturing method of a fixing structure of a trawl that includes a pair of struts that are vertical members and a traverse horizontally mounted between the pair of struts, and that fixes an end of the traverse to the strut,
At least in part, there is an inclined portion that is inclined with respect to a direction perpendicular to the axial direction of the step rail, and the end portion of the step rail is fixed to the inclined portion between the pair of struts. A step of preparing a support column provided with a vertical portion having an insertion hole while forming support surfaces perpendicular to the axial direction of the step rail in a horizontally mounted state on both the inside and outside of the column;
A main body portion forming a first clamping surface that contacts an inner support surface of the support surfaces as end surfaces on both sides in the axial direction, and a cylindrical projection portion that is a portion protruding in a cylindrical shape from the first clamping surface; And preparing a step rail member that constitutes the step rail by being fixed between the pair of columns, and
Passing the tubular projecting portion through the insertion hole, and projecting the tubular projecting portion from the vertical portion outward in the axial direction;
In a state where the first clamping surface is in contact with the inner support surface, the cylindrical projecting portion is separated from the first clamping surface by a pressing die having a pressing surface that contacts the end surface of the cylindrical projecting portion. By pressing in a direction opposite to the protruding direction, a sandwiching portion that forms a second sandwiching surface that faces the first sandwiching surface and contacts the outer support surface of the support surface is bent and the sandwiching is performed. And a step of press-clamping the vertical portion between the portion and the main body portion. The step of preparing the crosspiece member includes
A step of preparing a linear molded part having a hollow cylindrical core part having an annular shape in cross section and a tread surface forming part provided outside the cylindrical core part to form a flat tread surface; ,
The step of forming the cylindrical projecting portion by exposing the cylindrical core portion by removing portions of the tread surface forming portion at both end portions of the molded part. Of manufacturing a fixing structure for a pedestrian crossing.

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