JP6423196B2 - Ladder stepladder - Google Patents

Description

  The present invention relates to a ladder and stepladder that also serves as a stepladder and a ladder, and more particularly, to a connection structure between ladder bodies having a pair of struts and a step rail laid across the pair of struts.

  Conventionally, there is a ladder / ladder that also serves as a stepladder and a ladder. As a ladder combined stepladder, a pair of ladder bodies having a pair of struts and a step rail laid horizontally between the pair of struts are provided, and the upper ends of these ladder bodies are connected to each other via joint fittings that are connecting members. Some have a configuration in which the crossing direction (left and right direction) of the crosspiece is pivotally connected with the direction of the rotation axis as a rotation axis direction.

  The joint fitting is provided at the upper end portion of each column constituting the ladder body. And in a pair of ladder bodies facing each other, struts on the common side in the left-right direction are connected to each other via joint fittings provided at the respective upper ends. That is, the joint fitting is a member that constitutes a hinge portion between the struts to be coupled to each other, and the joint fittings provided at the upper end portions of the respective struts are rotatably coupled with the left-right direction as the pivot axis direction. Thus, the struts corresponding to each of the left and right sides are rotatably connected via a pair of fittings. Thereby, a pair of ladder bodies are connected to each other.

  Such a ladder-supporting stepladder is configured to be foldable so that a pair of ladder bodies that are coupled to each other via a joint fitting so as to be rotatable are substantially parallel to each other in a side view. When the ladder-supporting stepladder is used as a stepladder (when the stepladder is used), the pair of ladder bodies is in a state of being opened in a predetermined amount with a substantially inverted “V” shape in a side view. In such a ladder-ladder with a stepladder state, the opening of the ladders is restricted by a predetermined amount or more by a stopper metal provided between the pair of ladders. On the other hand, when the ladder combined stepladder is used as a ladder (when the ladder is used), the pair of ladder bodies are rotated and opened until they become substantially straight in a side view. In such a ladder-like stepladder in the ladder state, the columns in a state where they are connected to each other via the joint metal fittings are substantially straight in a side view with the upper end sides facing each other. Thus, the angle formed by the pair of ladder bodies in the ladder state is the maximum rotation angle of the angle formed by the pair of ladder bodies that are rotatably connected by the fittings.

  In the ladder-ladder stepladder as described above, the joint fitting for connecting the ladder bodies is generally a plate-like member, and the outer side surface (the side on which the tram is provided) at the upper end portion of each column by a fixing member such as a rivet. It is fixed with the plate surface along the opposite side surface. Each joint fitting includes a fixed portion fixed to the support column and a hinge portion protruding from the fixed portion and connected to the counterpart joint fitting. Then, the overlapping portions of the hinge portions of the joint fitting are connected to each other by a pivotal support member such as a pivot pin (see, for example, Patent Document 1).

  Thus, the plate-shaped joint fitting provided at the upper end of each column is provided with the upper end protruding above the upper end of the column. The joint brackets connected to each other support the pair of ladder bodies that are substantially straight in a side view in a ladder-like stepladder in a ladder state in which the upper end portions are in contact with each other. In other words, the pair of joints that are pivotably connected to each other between the support columns facing each other are in a state where the upper end surfaces are joined to each other in the ladder state, and are rotated so as to open from the stepladder state, and are substantially straight in a side view. Further rotation of the pair of ladder bodies in a shape is restricted, and it is involved in maintaining the ladder state of the ladder and stepladder.

  Patent Document 1 describes a technique that employs a bite-type structure as a technique for preventing a lateral shift (misalignment) between the fittings when the ladder is used, regarding the fittings for the ladder and stepladder. Specifically, in Patent Document 1, in the upper end portions of the plate-like joint fittings connected to each other between the struts facing each other, the fitting protrusion provided on one joint fitting side and the other joint fitting side are provided. The structure which has the protrusion insertion pocket provided is disclosed. According to such a configuration, the fittings connected to each other at the maximum rotation angle at which the pair of ladder bodies form a ladder state engage the fitting protrusions and the protrusion insertion pockets provided at the respective upper ends with each other. To be joined.

Japanese Utility Model Publication No. 6-31118

  Certainly, according to the configuration described in Patent Document 1, even if a large load is applied to the joint fitting when using the ladder, or wear or deformation occurs at the joint portion of the upper end of the joint fitting due to long-term use, It is possible to prevent lateral shift (misalignment) between the fittings. However, the structure using the conventional fitting as described above has the following problems.

  When using a ladder that also serves as a ladder, a very large load is applied to the fitting that joins the upper ends to each other. Such a load acts as a shearing force on a fixing member such as a rivet that fixes the joint fitting to the support column. That is, the load acting on the joint fitting when the ladder is used is received by the fixing member that fixes the joint fitting to the support column. For this reason, about fixing members, such as a rivet which fixes a joint metal fitting to a support | pillar, a considerable fixed strength is required and the number corresponding to it is required. A large number of fixing members such as rivets increases the number of parts of the ladder and stepladder and increases the number of manufacturing steps.

  In addition, since the conventional fitting is a plate-like member and receives a large load when the ladder is used with its upper ends joined to each other, the lateral displacement between the fittings as described above, From the viewpoint of preventing deformation of the metal fitting, it is necessary to ensure a considerable degree of strength for the joint member itself. For this reason, steel members are used as conventional fittings. The steel member is relatively heavy, and causes the weight of the ladder and stepladder to be increased.

  The present invention has been made in view of the above-described problems of the prior art, and relates to a joint member that rotatably connects ladder bodies to each other, and has a simple structure and sufficient load resistance when using the ladder. It is an object to provide a ladder and stepladder that can be easily reduced in weight.

  The ladder-combined stepladder according to the present invention includes a pair of ladder bodies each having a pair of support pillars that are vertical members and a step rail horizontally mounted between the pair of support pillars. A ladder-supporting stepladder that is pivotably connected with the erection direction as a rotation axis direction, and is provided at the upper end portion of each of the columns constituting the ladder body, and the pair of ladder bodies connected to each other, It has a joint member that rotatably connects the support columns on the same side in the installation direction with the installation direction as a rotation axis direction, and the connection member is inserted into the upper end portion of the support column in the state where the upper end portion is inserted. A pair of ladder bodies as mating surfaces to the joint member to be connected to each other in a state in which the rotation angle of the pair of ladder bodies is a maximum rotation angle in which the pair of ladder bodies form a ladder state. A support surface that supports the load in the direction of opening And insertion portion which protrudes from a side surface of the insertion portion, and a hinge portion connected to the catch member of the counterpart, and has a.

  Further, in the ladder-supporting stepladder according to one aspect of the present invention, the hinge portion is a plate-like portion having the erection direction as a plate thickness direction in a state where the joint member is mounted on the column, and is connected to each other. The hinge portion of each of the pair of joint members is provided so that a plate surface on one side substantially coincides with the center position of the insertion portion in the plate thickness direction.

  Also, in the ladder-supporting stepladder according to one aspect of the present invention, the insertion portion has the outer shape of the column along the outer cross-sectional shape of the column, and at least one side in the cylinder axis direction is opened as the insertion port of the column. It is a cylindrical part which forms the insertion space.

  Further, in the ladder combined stepladder according to one aspect of the present invention, the insertion portion is formed by opening both sides of the insertion space in the cylinder axis direction, and is open from the opening on the opposite side to the insertion port of the insertion space. A cap member that is fitted into the insertion portion and forms the support surface together with the insertion portion is further provided.

  Further, in the ladder-supporting stepladder according to one aspect of the present invention, the insertion portion includes the pair of members that constitute the ladder body on an outer wall surface portion in the erection direction in a state where the joint member is attached to the column. A hole for processing for fixing the step rail, which is laid between the upper end portions of the column, to the column, and the cap member is inserted into the insertion portion in the state of being inserted into the insertion portion. It has a fitting protrusion which fits into the hole from the inside of the part.

  According to the present invention, with respect to the joint member that connects the ladder bodies to each other so as to be rotatable, a simple structure can provide sufficient load resistance when the ladder is used, and the weight can be easily reduced.

It is a perspective view which shows the stepladder state of the ladder combined stepladder which concerns on one Embodiment of this invention. It is a front view which shows the stepladder state of the ladder combined stepladder which concerns on one Embodiment of this invention. It is a side view which shows the stepladder state of the ladder combined stepladder which concerns on one Embodiment of this invention. It is a front view which shows the ladder state of the ladder and stepladder which concerns on one Embodiment of this invention. It is a side view which shows the ladder state of the ladder combined stepladder which concerns on one Embodiment of this invention. It is a side view which shows the folding state of the ladder combined stepladder which concerns on one Embodiment of this invention. It is a perspective view which shows the connection structure of the ladder body which concerns on one Embodiment of this invention. It is a figure which shows the connection structure of the ladder body in the stepladder state of the ladder combined stepladder which concerns on one Embodiment of this invention. It is a figure which shows the connection structure of the ladder body in the ladder state of the ladder combined stepladder which concerns on one Embodiment of this invention. It is a figure which shows the connection structure of the ladder body in the folding state of the ladder combined stepladder which concerns on one Embodiment of this invention. It is a partial cross section figure which shows the connection structure of the ladder body in the ladder state of the ladder combined stepladder which concerns on one Embodiment of this invention. It is a top view which shows the connection structure of the ladder body which concerns on one Embodiment of this invention. It is a figure which shows the joint member which concerns on one Embodiment of this invention. It is a figure which shows the connection state of the joint member which concerns on one Embodiment of this invention. It is a figure which shows the cap member which concerns on one Embodiment of this invention. It is a figure which shows the opening stop mechanism which concerns on one Embodiment of this invention. It is explanatory drawing about the manufacturing method of the joint member which concerns on one Embodiment of this invention. It is explanatory drawing about the manufacturing method of the connection structure of the ladder body which concerns on one Embodiment of this invention. It is a top view which shows the other structural example of the connection structure of the ladder body which concerns on one Embodiment of this invention. It is a top view which shows the other structural example of the connection structure of the ladder body which concerns on one Embodiment of this invention.

  The present invention is a ladder connecting structure that rotatably connects a pair of ladder bodies in a ladder-supporting stepladder, by devising a structure of a joint member provided at an upper end portion of each column constituting the ladder body, etc. The present invention aims to simplify the structure and improve load resistance when using a ladder, and to provide a structure suitable for weight reduction. Embodiments of the present invention will be described below.

[Overall configuration of ladder-ladder stepladder]
First, the overall configuration of the ladder and stepladder 1 according to the present embodiment will be described with reference to FIGS. 1 to 6. As shown in FIGS. 1 to 6, the ladder / stepladder 1 according to the present embodiment also serves as a stepladder and 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 columns 3 that are vertical members, and a plurality of step bars 4 that are horizontally mounted between the pair of columns 3 that are disposed at a predetermined interval. The ladder-combined stepladder 1 has a configuration in which a pair of ladder bodies 2 are connected so as to be rotatable with the installation direction of the step rail 4 (the direction in which the step rail 4 is horizontally mounted) as the rotation axis direction. In the ladder body 2, the direction in which the pair of support columns 3 face each other, that is, the installation direction of the tram 4 (the left-right direction in FIG. 2) is the left-right 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 ladder-supporting stepladder 1, the inclined portions 3 b 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 when the stepladder-supporting stepladder 1 is used.

  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 formed as a portion having a U-shaped cross-sectional shape, and a side wall 3x serving as a wall surface facing each other in the pair of columns 3 and the side wall 3x continuously from both ends of the side wall 3x. And a pair of end wall portions 3y facing each other.

  The pair of support columns 3 is provided with the side wall 3x 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.

  Coupling bracket which is a coupling member in which the ladder bodies 2 constituted by the support columns 3 and the crosspieces 4 as described above are paired and the upper end portions which are narrow with respect to the lower portion function as connecting members. 6, the left and right directions are pivotally connected to each other so as to be rotatable. The joint fitting 6 is provided at the upper end of each support column 3, and in the 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 joints provided at each upper end portion. It is rotatably connected via a metal fitting 6. That is, the joint fitting 6 is a member constituting a hinge portion between the pillars 3 to be connected to each other, and the corresponding pillars 3 on the left and right sides of the stepladder 1 are provided at the upper end of each pillar 3. 6 are connected to each other via a pair of joint fittings 6 so that the left and right directions can be freely rotated. 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.

  As described above, in the ladder-supporting 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, between the columns 3 connected to each other via the joint metal fittings 6 on both the left and right sides. An opening prevention mechanism 8 is provided. The anti-opening mechanism 8 is provided on the outer side in the left-right direction of the pair of joint fittings 6 connected to each other, and is a half-fold type comprising two plate-like arm portions whose ends are connected to each other so as to be relatively rotatable. It has the structure of.

  When the stepladder 1 is used as the ladder stepladder 1, the opening preventing mechanism 8 is in a state of being spanned between the upper ends of the columns 3, thereby restricting the rotation of the ladder bodies 2 in the opening direction. That is, when the stepladder 1 is used as a ladder, the pair of ladder bodies 2 are substantially reversed so as to follow the hypotenuse of an isosceles triangle whose apex is the center of rotation of the joint bracket 6 when viewed from the side by the support 3. ”And a predetermined amount opened, and in this state, the opening preventing mechanism 8 is bridged between the upper end portions of the support columns 3 in a substantially horizontal direction, so that the ladder bodies 2 are opened more than a predetermined amount. Is regulated. The structure of the locking mechanism 8 will be described later.

  The ladder and stepladder 1 of the present embodiment having the above-described configuration can be folded so that a pair of ladder bodies 2 that are connected to each other via a joint metal fitting 6 are substantially parallel to each other in a side view. It is configured (see FIG. 6). In the folded state of the ladder-ladder 1, the folding mechanism 8 is bent in a substantially inverted “V” shape by the rotation of the two plate-like portions between the ladder bodies 2 that are substantially parallel to each other. It becomes a state.

  When the stepladder 1 is used, the pair of ladders 1 is in a state in which the pair of ladder bodies 2 has a substantially inverted “V” shape in a side view and is opened by a predetermined amount (see FIGS. 1 to 3). reference). In such a ladder-ladder 1 in a stepladder state, the opening prevention mechanism 8 restricts the opening of the ladder bodies 2 by a predetermined amount or more.

  On the other hand, when the ladder is used, the ladder-supporting stepladder 1 is in an open state until the restriction of the rotation by the opening preventing mechanism 8 is released and the pair of ladder bodies 2 are straight in a side view (FIG. 4). FIG. 5). In such a ladder combined stepladder 1 in such a ladder state, the support columns 3 connected to each other via the joint metal fitting 6 are substantially straight in a side view with the upper end sides facing each other. Are substantially continuous with each other. That is, the ladder combined stepladder 1 in the ladder state has a length (height) twice that of the ladder body 2. Thus, the angle (about 180 °) formed by the pair of ladder bodies 2 in the ladder state is the maximum rotation angle of the angle formed by the pair of ladder bodies 2 that are rotatably connected by the joint metal fitting 6. In the ladder-ladder stepladder 1 in the ladder state, the anti-opening mechanism 8 is placed between the columns 3 along the linear direction between the columns 3 that are substantially straight in a side view. It functions to fix and hold the linear form. The ladder stepladder 1 in the ladder state is used in a state where it is leaned against a wall 9 or the like as shown in FIG.

  The ladder and stepladder 1 according to the present embodiment having the above-described configuration has a characteristic configuration with respect to a connection structure of the pair of ladder bodies 2 by the fittings 6 and the like. Hereinafter, the connection structure of the ladder body 2 provided in the ladder / stepladder 1 according to the present embodiment will be described in detail with reference to FIGS. 7 to 19. 7, 12, and 19, the illustration of the opening prevention mechanism 8 is omitted.

[Ladder structure]
First, the fitting 6 provided in the connecting structure of the ladder body 2 will be described. The fitting 6 is provided at the upper end of each column 3 constituting the ladder body 2, and the columns 3 on the same side of the pair of ladder bodies 2 connected to each other in the installation direction (left-right direction) of the step rail 4. Are coupled so as to be rotatable with the left-right direction as the rotation axis direction.

  In the connecting structure of the ladder bodies 2 according to the present embodiment, a pair of ladder bodies 2 arranged in a direction in which the installation direction of the traversing rail 4 is common to each other, the upper ends of the columns 3 on the same side in the left-right direction are connected to each other. Each of the left and right sides has a configuration in which they are connected to each other by a pair of joint fittings 6 provided at the upper end of each support column 3. In other words, the support posts 3 that are located on the same side in the left-right direction in the ladder-supporting stepladder 1 and that constitute different ladder bodies 2 can rotate the joint fittings 6 provided at the upper ends of the support posts 3 with each other. By connecting, it connects so that rotation is mutually possible, and, thereby, a pair of ladder bodies 2 are connected so that rotation is mutually possible. Accordingly, the ladder / stepladder 1 of the present embodiment includes a total of four joint brackets 6 each including a pair of joint brackets 6 connected to each other.

  A pair of fittings 6 for connecting the columns 3 to each other on the left and right sides of the ladder-ladder 1 are connected to each other so that the left and right directions can be rotated. The struts 3 connected to each other by the pair of joint fittings 6 become the struts 3 facing each other in relation to the other ladder body 2 in the folded ladder / ladder 1. The position of the rotation axis of the joint fitting 6 connected to each other is the position of the rotation axis of the pair of ladder bodies 2.

  The connection structure including a pair of joint fittings 6 that connect the support columns 3 to each other on the left and right sides of the ladder-ladder 1 is provided with a common configuration and is configured symmetrically (see FIG. 12).

  The joint fitting 6 according to the present embodiment protrudes from an insertion portion 10 which is a portion fixed to the column 3 with the upper end portion of the column 3 being inserted, and one side surface of the insertion unit 10, It has the hinge part 20 connected with the joint metal fitting 6. FIG. That is, with respect to the pair of joint fittings 6 that are connected to each other, each joint fitting 6 is provided in a state of being externally fitted to each column 3 by the insertion portion 10, and the pair of joint fittings 6 are respectively hinge portions. 20 are connected to each other.

  The insertion portion 10 has a vertically long plate-like outer shape with the left-right direction as the plate thickness direction and the up-down direction as the longitudinal direction, and is configured in a substantially rectangular tube shape with both sides in the longitudinal direction opened. Therefore, the insertion portion 10 is a relatively wide plate surface portion (side wall portion) whose left-right direction is the plate thickness direction, and a pair of wide surface portions (11, 12) facing each other in the left-right direction, and the pair And a pair of narrow surface portions (13, 14) facing each other (see FIG. 12).

  Specifically, the insertion portion 10 is a pair of wide surface portions opposed to each other, and the inner wide surface portion 11 positioned on the inner side in the left-right direction in a state where the joint fitting 6 is provided at the upper end portion of the support column 3. 6 has an outer wide surface portion 12 positioned on the outer side in the left-right direction in a state where it is provided on the column 3. Moreover, the insertion part 10 is a folded state in the state in which the joint metal fitting 6 is provided in the support | pillar 3 as a pair of narrow surface part mutually opposed in the direction orthogonal to the left-right direction seeing the cylinder axis direction of the insertion part 10 The opposite side narrow surface portion 13 which is the side facing the other side of the joint metal fitting 6 connected to the ladder combined stepladder 1 and the non-opposing side narrow surface portion 14 opposite to the opposing side narrow surface portion 13 are provided.

  In this manner, the insertion fitting portion 10 constituting the joint fitting 6 has four side wall portions, that is, an inner wide surface portion 11, an outer wide surface portion 12, an opposing side narrow surface portion 13, and a non-opposing side narrow surface portion 14. These side wall portions are configured as a square cylindrical portion having both sides in the cylindrical axis direction opened. And the insertion part 10 makes the cylinder axial direction in the square cylindrical external shape the insertion direction with respect to the upper end part of the column 3, and fits the upper end part of the column 3 with the upper end part of the column 3 being fitted. Is done.

  In other words, the insertion portion 10 follows the outer shape of the cross section of the support column 3 and has an insertion space of the support column 3 opened at least on one side in the cylinder axis direction (lower side in the present embodiment) as the insertion port 10b of the support column 3. It is provided as a cylindrical part forming 10a. The insertion portion 10 forms a space having a common cross-sectional shape in the cylinder axis direction of the insertion portion 10 as the insertion space 10a, that is, a linear space along the cylinder axis direction. An insertion space 10a corresponding to the outer shape of the cross-sectional shape of the column 3 is formed so that the upper end, that is, the upper end of the vertical portion 3a is inserted.

  Specifically, in the present embodiment, the support column 3 includes a side wall portion 3x and a pair of end wall portions 3y facing each other as a portion having a “U” -shaped cross-sectional shape as described above. With respect to such a support column 3, the insertion fitting portion 10 constituting the joint metal fitting 6 has the inner wide surface portion 11 as a side wall in a state of being externally fitted to the support column 3, that is, in a state where the support column 3 is inserted into the insertion space 10a. Along the portion 3x, the opposing narrow surface portion 13 and the non-opposing narrow surface portion 14 are each along the end wall portion 3y, and the outer wide surface portion 12 is opposed to the side wall portion 3x (see FIG. 12). .

  The insertion part 10 is fixed to the support column 3 by rivets 15. In the present embodiment, as described above, the portion of the inner wide surface portion 11 along the side wall portion 3 x of the support column 3 is fixed to the side wall portion 3 x of the support column 3 by the rivet 15. That is, the rivet 15 penetrates the inner wide surface portion 11 of the insertion portion 10 and the side wall portion 3x located inside the inner wide surface portion 11 in a state where the insertion portion 10 is externally fitted to the upper end portion of the column 3. In this state, the joint fitting 6 is fixed to the column 3. For this reason, rivet holes 3r and 11r for penetrating the rivets 15 are formed in the side wall 3x of the support column 3 and the inner wide surface portion 11 of the insertion portion 10, respectively.

  In the present embodiment, two rivets 15 are used to fix the joint fitting 6 to the column 3. Specifically, the rivet hole 11r on the side of the insertion portion 10 has two positions spaced apart from each other by a predetermined distance in the width direction of the inner wide surface portion 11 at a position closer to the lower side in the vertical direction of the inner wide surface portion 11. Is provided. On the other hand, in the side wall portion 3x of the column 3, rivet holes 3r are provided at two positions corresponding to the rivet holes 11r in a state where the insertion portion 10 is externally fitted to the column 3. Note that the number, position, and the like of the fixing portion by the rivet 15 are not particularly limited.

  Thus, the insertion part 10 fixed to the support column 3 by the rivet 15 is configured such that the upper end protrudes slightly above the upper end of the support column 3 in a state of being fixed to the support column 3. That is, in a state where the insertion portion 10 is fixed to the upper end portion of the support column 3, the upper end surface 3s of the support column 3 is positioned below (inside) the opening end surface 10s on the upper side of the insertion portion 10 (FIG. 11). reference).

  The hinge part 20 protrudes from the opposing side narrow surface part 13 which becomes the side part on the other side of the joint metal fitting 6 side in the ladder-like stepladder 1 in the folded state or the stepladder among the side parts constituting the insertion part 10. Is provided. The hinge portion 20 has a plate thickness in the installation direction (left-right direction) of the treadle 4 in a state where the fitting 6 is attached to the column 3 (externally fitted, hereinafter referred to as “attached state” for the fitting 6). It is a plate-like part which makes a direction. That is, the hinge portion 20 is a flat plate-like portion in which the inner wide surface portion 11 and the outer wide surface portion 12 in the insertion portion 10 face each other (the left-right direction in FIG. 12).

  Specifically, the plate-like hinge portion 20 is provided at a substantially central position in the left-right direction in the opposed-side narrow surface portion 13 constituting the insertion portion 10. In addition, the hinge portion 20 is provided so as to protrude in a direction perpendicular to the plate surface of the opposing narrow surface portion 13 from substantially the entire vertical range of the opposing narrow surface portion 13.

  The hinge part 20 has a vertically long outer shape having a width dimension substantially half of the width dimension of the inner wide surface part 11 and the outer wide surface part 12 constituting the insertion part 10. The hinge part 20 is a vertical part 21 along the cylinder axis direction (vertical direction) of the insertion part 10 as an end surface part opposite to the insertion part 10 side, that is, an end surface part protruding from the insertion part 10, And an inclined portion 22 provided on the lower side of the vertical portion 21. The inclination part 22 inclines so that it may approach the insertion part 10 side (base end part side of the hinge part 20) gradually from the upper side to the lower side below the vertical part 21.

  The vertical portion 21 is provided in a substantially upper half portion of the hinge portion 20, and the inclined portion 22 is provided in a substantially lower half portion of the hinge portion 20. In other words, the hinge portion 20 has a substantially rectangular portion with an equal width in the vertical direction as a substantially upper half portion, and a substantially triangular portion gradually narrowing from the upper side to the lower side as a substantially lower half portion. The vertical portion 21 serving as the projecting side end surface of the substantially upper half of the hinge portion 20 has a narrow width on the opposite side of the other side to be coupled in the ladder-like stepladder 1 in the folded state where the pair of ladder bodies 2 are in the most closed state. It faces the wall surface of the surface portion 13.

  Further, the upper end portion of the hinge portion 20 is provided with a shaft support portion 23 that protrudes in a semicircular shape from substantially the entire width direction of the hinge portion 20 toward the upper side. In the vertical direction of the joint fitting 6, the shaft support portion 23 is set so that the center position of the virtual circumference along the semicircular outer shape is substantially the same as the position of the opening end surface 10 s that is the upper end surface of the insertion portion 10. Is provided. The position of the center of the virtual circumference along the semicircular outer shape of the shaft support portion 23 is the position of the center of rotation of the pair of fittings 6 that are rotatably connected to each other.

  That is, in the hinge part 20, a shaft support member such as a bolt or a pin penetrates in the plate thickness direction of the hinge part 20 in accordance with the center of the virtual circumference, and the pair of joint fittings 6 are connected to each other in a rotatable manner. To do. For this reason, a shaft support hole 24 for penetrating a shaft support member such as a bolt or a pin is formed in the center of the virtual circumference. The pair of joint fittings 6 that are connected to each other are overlapped by the hinge members 20 so that the positions of the shaft support holes 24 coincide with each other, and are inserted into the shaft support holes 24 that are overlapped with each other. The shaft is supported so as to be relatively rotatable.

  In the present embodiment, a bolt 25 is used as a shaft support member that penetrates the overlapping hinge portion 20. The bolt 25 is inserted into the overlapping hinge part 20 from the outside in the left-right direction, and the nut 26 is screwed to the inward protruding part from the hinge part 20. A washer is appropriately interposed between the bolt 25 and the hinge part 20 and between the nut 26 and the hinge part 20.

  In this way, between the columns 3 connected to each other by the pair of joint fittings 6, the overlapping portions of the hinge portions 20 of the respective joint fittings 6 are connected so as to be relatively rotatable by bolts 25 or the like serving as shaft support members. Thus, the support columns 3 are rotatably connected to each other through the joint fittings 6 fixed to the support columns 3. Such a connection structure is provided on both the left and right sides of the ladder-supporting stepladder 1, and the pair of ladder bodies 2 are connected to each other so as to be rotatable around the position of the bolt 25. The relative rotation range of the pair of ladder bodies 2 is such that the ladder of the ladder / ladder 1 in which the pair of ladder bodies 2 is in the most open state from the folded state of the ladder / ladder 1 in which the pair of ladder bodies 2 is closed. Up to the state.

  Moreover, in the connection structure of the ladder body 2 according to this embodiment, the hinge part 20 included in each of the pair of joint fittings 6 connected to each other has a plate surface on one side, and the plate of the hinge part 20 in the insertion part 10. It is provided so as to substantially coincide with the center position in the thickness direction. Specifically, it is as follows.

  As shown in FIGS. 14 (a) and 14 (b), the pair of joint fittings 6 connected to each other are bolts in a state where the hinge portions 20 are overlapped with each other in the plate thickness direction (vertical direction in FIG. 14 (a)). 25 or the like. In this embodiment, regarding the pair of joint brackets 6 on one side (left side in FIG. 12) of the ladder-standing stepladder 1 in the folded state or the stepladder state, the side view from the one side (FIGS. 10 and 14). In (b)), when the joint fitting 6 located on the left side is the first joint fitting 6A and the joint fitting 6 located on the right side is the second joint fitting 6B, the first joint fitting 6A is the hinge part 20 thereof. Is positioned on the inner side in the left-right direction with respect to the hinge portion 20 of the second fitting 6B. The fitting 6 shown in FIG. 13 corresponds to the first fitting 6A in this case.

  In such a configuration, the hinge portion 20 of the first joint fitting 6A is in the left-right direction in the mounted state of the first joint fitting 6A with respect to the insertion portion 10, that is, the thickness direction of the hinge portion 20 (FIG. 14 (a)). ) In the vertical direction), the plate surface 20a on the side facing (contacting) the hinge portion 20 of the second fitting 6B is approximately at the center position of the insertion portion 10 (see FIG. 14A, straight line M1). Match. On the other hand, the hinge portion 20 of the second fitting 6B is hinged to the insertion fitting 10 in the left-right direction (the thickness direction of the hinge portion 20) in the mounting state of the second fitting 6B. The plate surface 20b on the side facing (contacting) the portion 20 is made to substantially coincide with the center position of the insertion portion 10 (see FIG. 14A, straight line M1).

  That is, in the connecting structure on one side in the left-right direction (the left side in FIG. 12) of the ladder-supporting stepladder 1, the first joint fitting 6A for positioning the hinge portion 20 on the inner side in the left-right direction has the hinge portion 20 in the left-right direction. The outer plate surface 20a is provided so as to be positioned at the approximate center in the width direction of the outer shape of the insertion portion 10 (the thickness direction of the hinge portion 20). Further, in the connection structure, the second joint fitting 6B for positioning the hinge portion 20 on the outer side in the left-right direction has the hinge portion 20 whose inner plate surface 20b in the left-right direction has the width direction of the outer shape of the insertion portion 10 ( The hinge portion 20 is provided so as to be positioned substantially at the center).

  According to such a configuration, the position where the first joint fitting 6 </ b> A and the second joint fitting 6 </ b> B connected to each other join the hinge parts 20 is the center position of the insertion part 10 in the plate thickness direction of the hinge part 20 ( 14 (see line M1 in FIG. 14). In other words, the position of the mating surface where the pair of joint fittings 6 connected to each other join the hinge portions 20 is positioned at the approximate center of the insertion portion 10 in the thickness direction of the hinge portion 20.

  In the present embodiment, the connection structure including the pair of joint fittings 6 for connecting the columns 3 to each other on the left and right sides of the ladder-supporting stepladder 1 is symmetrically configured as described above. Therefore, as shown in FIG. 12, with respect to the pair of joint brackets 6 on the other side (right side in FIG. 12) in the left-right direction of the ladder / ladder 1 in the folded state or the stepladder state, the ladder in the folded state or the stepladder state is provided. The joint fitting 6 (6C) located on the same side as the first joint fitting 6A (upper side in FIG. 12) in the side view of the dual-purpose stepladder 1 is connected to the other joint fitting 6, that is, in the side view. It is located on the inner side in the left-right direction with respect to the hinge portion 20 of the joint fitting 6 (6D) located on the same side as the second joint fitting 6B (lower side in FIG. 12).

  Moreover, in the connection structure of the ladder body 2 according to the present embodiment, the joint fitting 6 is fastened together with the uppermost step rail 4 (4A) of the step rails 4 included in the ladder body 2 with respect to the support column 3. Fixed in state. That is, the joint fitting 6 is fixed to the support column 3 not only by the rivet 15 as described above but also by the uppermost step rail 4A. Specifically, it is as follows.

  As shown in FIG. 11, in the state in which the joint fitting 6 is mounted, the crosspiece 4 </ b> A is in a state of penetrating through the inner wide surface portion 11 of the insertion portion 10 and the side wall portion 3 x located inside the inner wide surface portion 11. The metal fitting 6 is fixed to the column 3. Therefore, treadle through-holes 3t and 11t for penetrating the treadle 4A are formed in the side wall 3x of the column 3 and the inner wide surface part 11 of the insertion portion 10, respectively.

  The step rail 4A has an enlarged diameter with respect to the step rail through holes 3t and 11t from the inner side of the left and right support columns 3 to the end portion in the longitudinal direction passing through the inner wide surface portion 11 of the insertion portion 10 and the side wall portion 3x of the support column 3. It has the collar part 18 which is a part. In the state in which the inner wide surface portion 11 and the side wall portion 3x are sandwiched between the crosspiece 4A and the main body portion 17 which is a portion located between the left and right support columns 3 by the flange portion 18, the joint fitting 6 is supported by the support rail 6A. 3 is fixed. That is, the flange portion 18 is a portion that presses and holds the inner wide surface portion 11 and the side wall portion 3x together with the main body portion 17 (see FIG. 11).

  As described above, the step rail 4A includes the main body portion 17 located between the side wall portions 3x of the left and right support columns 3 (between the inner wide surface portions 11 of the joint fitting 6) and the sandwiching portions provided on the left and right outer sides of the main body portion 14. And a collar portion 18 as The step rail 4A forms a first clamping surface 17u that contacts the outer surface 11u of the inner wide surface portion 11 of the joint fitting 6 at the longitudinal end portion of the main body portion 17, and the side wall of the column 3 at the flange portion 18. A second clamping surface 18u that contacts the inner side surface 3u of the portion 3x is formed. That is, in the state where the crosspiece 4A is fixed to the support column 3, the first clamping surface 17u that is the end surface in the longitudinal direction of the main body portion 17 and the second clamping surface 18u of the flange portion 18 that faces the first clamping surface 17u. As a result, the inner wide surface portion 11 and the side wall portion 3x, which are plate portions overlapping each other, are sandwiched from both the left and right sides.

  As described above, the step rail 4A that passes through the end portion in the longitudinal direction through the inner wide surface portion 11 and the side wall portion 3x and fixes the joint fitting 6 to the column 3 has the main body portion 17 and the flange portion 18 at the end portion in the longitudinal direction. And a cylindrical portion 17v which is a protruding portion from the first clamping surface 17u and is located in the traverse through holes 3t and 11t (see FIG. 11).

  In the fixing structure of the joint bracket 6 to the support column 3 by the step rail 4A as described above, the step rail 4A has a protruding portion from the first clamping surface 17u on both ends in the longitudinal direction in a state before processing (before fixing). The cylindrical workpiece is compressed and deformed in a state of protruding outward in the left-right direction via the step-through through holes 3t, 11t in the left and right support columns 3, thereby forming the flange portion 18 and the support column 3 On the other hand, the joint fitting 6 and the tread bar 4 are fixed by caulking.

  In the step of caulking and fixing with the formation of the flange portion 18 as described above, the cylindrical workpieces protruding from the step rail through holes 3t and 11t are pressed along the longitudinal direction of the step rail 4A at both ends of the step rail 4A. A pressing die such as a punch is used. That is, by using this pressing mold, the flange 18 is formed by compressing and deforming the cylindrical workpiece to be protruded outward in the left-right direction through the through-holes 3t and 11t, and the accompanying cross-pieces. A processing step of caulking and fixing the support column 3 and the joint fitting 6 by 4A is performed.

  Therefore, the insertion fitting portion 10 constituting the joint fitting 6 has a pair of support columns 3 constituting the ladder body 2 on the outer wide surface portion 12 which is the outer wall surface portion in the installation direction of the step rail 4 with the fitting fitting 6 attached. There is a hole for processing for fixing the crosspiece 4 </ b> A, which is mounted between the upper end portions, to the column 3. In the present embodiment, in the joint metal fitting 6, the above-described caulking process is performed in a state of being attached to the support column 3, so that the outer wide surface portion 12 facing the inner wide surface portion 11 is used as the processing hole. A hole 12t is formed.

  The processing hole portion 12t is cylindrical when the processing is performed so that the cylindrical processed portion of the step rail 4A that protrudes from the step rail through holes 3t and 11t and is located inside the fitting 6 is used as the flange portion 18. A pressing-type path such as a punch that acts on the part to be processed is secured. In other words, when processing the cylindrical processed portion of the crosspiece 4A located inside the fitting 6, the pressing die passes through the insertion space 10a of the insertion portion 10 via the processing hole 12t. It acts on the part to be processed in the metal fitting 6.

  In the present embodiment, the processing hole portion 12t provided in the outer wide surface portion 12 is a circular hole portion, and in the insertion portion 10 of the joint fitting 6, the side crossing on the inner wide surface portion 11 side is seen in a side view. It is formed in a concentric position with respect to the hole 11t with a hole diameter that is slightly larger than that of the traverse through hole 11t (see FIG. 13C). Note that the step rail through hole 3t of the column 3 and the step rail through hole 11t of the inner wide surface portion 11 and the cylindrical processed portion (tubular portion 17v) of the step rail 4 inserted into these holes are defined as a step. It has an insertion shape in which relative rotation around the axial direction with respect to the column 3 of the beam 4A is restricted.

  Specifically, in this embodiment, the step rail through hole 3t of the support column 3 and the step rail through hole 11t of the inner wide surface portion 11 have substantially the same size and shape, and these step rail through holes 3t, 11t has a hole shape in which straight portions (see reference numeral 11w) are formed at two locations that are substantially opposed to each other in the circumferential shape (see FIG. 13C). Note that the insertion shape of the through-holes 3t and 11t and the parts to be processed (cylindrical portions 17v) inserted into these holes is not limited to this embodiment, and the post of the step-line 4A Any shape may be used as long as relative rotation with respect to 3 is restricted. 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 stepped-piece through holes 3t and 11t and the portion to be processed (cylindrical portion 17v) may be an irregular shape with respect to the circumferential shape that enables the stepped-piece 4A to rotate relative to the column 3.

  Moreover, in the ladder combined stepladder 1 of the present embodiment, among the plurality of step bars 4 provided in the ladder body 2, a portion other than the portion covered by the fittings 6 of the column 3, that is, a portion other than the upper end portion of the column 3. The fixing structure / fixing method with respect to the support column 3 similar to that of the uppermost step rail 4 </ b> A is appropriately adopted for the fixed rail 4 to be fixed. When the fixing structure / fixing method is adopted, the foot cross 4 is not interposed between the main body portion 17 which is a portion positioned between the left and right support columns 3 via the flange portion 18 without the inner wide surface portion 11 interposed therebetween. The joint fitting 6 is fixed to the support column 3 with only the side wall 3x of the support column 3 sandwiched. That is, in this case, in the fixing structure of the step bar 4 other than the uppermost step bar 4 </ b> A to the column 3, the step bar 4 is the first end surface in the longitudinal direction of the main body portion 17 in a state of being fixed to the column 3. Only the side wall 3x is sandwiched from both the left and right sides by the sandwiching surface 17u and the second sandwiching surface 18u of the flange 18 facing the first sandwiching surface 17u.

  As described above, in the joint fitting 6 that has the insertion fitting portion 10 and the hinge portion 20 and is pivotally connected to the counterpart fitting fitting 6 in the shaft support portion 23 of the hinge portion 20, the insertion fitting portion 10 A support surface 6s that is a mating surface (joint surface) of the pair of ladder bodies 2 is formed in the ladder-supporting stepladder 1 in the ladder state. In other words, the insertion fitting 10 that constitutes the joint fitting 6 is such that the pair of ladder bodies 2 are connected at the maximum turning angle at which the pair of ladder bodies 2 form a ladder state. A support surface 6s that supports a load in a direction in which the pair of ladder bodies 2 opens is formed as a mating surface for the two. In this embodiment, the insertion part 10 forms the support surface 6s of the joint fitting 6 by the upper opening end surface 10s in the rectangular cylindrical outer shape.

  In the ladder combined stepladder 1, the pair of ladder bodies 2 are substantially parallel to each other when viewed from the side, that is, the angle formed by the pair of ladder bodies 2 when viewed from the side is approximately 0 ° (see FIGS. 6 and 10). By the relative rotation due to the connecting structure of the pair of ladder bodies 2, the angle between the two is about 180 ° and the rotation is restricted until the rotation is restricted, and the ladder and stepladder 1 is in the ladder state (see FIGS. 5 and 9). It becomes. The regulation of the rotation of the pair of ladder bodies 2 in the ladder state is such that the support surfaces 6s, which are the upper end surfaces of the joint fittings 6 provided at the upper ends of the support columns 3, are contacted as mating surfaces. However, this is performed by the pair of ladder bodies 2 being in a state of stretching each other. Therefore, when using the ladder of the ladder combination stepladder 1, the support surfaces 6 s in contact with each other are loaded in a direction in which the rotation of the pair of ladder bodies 2 is restricted, that is, the pair of ladder bodies 2 is brought into the ladder state from the stepladder state. It becomes a surface that receives and supports a load that acts when opening more than about 180 °.

  Moreover, the connection structure of the ladder body 2 according to the present embodiment is fitted from the upper opening 10c into the insertion portion 10 having a substantially rectangular tube shape in which both sides in the cylinder axis direction (vertical direction) of the insertion space 10a are opened. The cap member 30 is provided. The cap member 30 is fitted into the insertion portion 10 through the opening 10 c on the opposite side of the insertion space 10 a of the insertion space 10 a of the fitting portion 10 of the joint fitting 6, and forms a support surface 6 s together with the insertion portion 10. In addition, illustration of the cap member 30 is abbreviate | omitted in FIG. That is, FIG. 12 is a diagram showing a state where the cap member 30 is not attached.

  The cap member 30 provided in the connecting structure of the ladder body 2 will be described. As shown in FIGS. 11 and 15A to 15D, the cap member 30 includes a plate-like lid portion 31 that closes the opening 10 c of the insertion portion 10, and a plate surface on one side of the lid portion 31. And an insertion portion that is provided so as to protrude from the back-side plate surface 31 b and is inserted into the insertion space 10 a of the insertion portion 10. That is, the cap member 30 is inserted into the insertion portion 10 so that the opening 30c on the upper side of the insertion portion 10 is closed by the lid portion 31, and the other side of the lid portion 31 (the back side plate surface). A support surface 6s is formed together with the opening end surface 10s of the insertion portion 10 by a front side plate surface 31a which is a plate surface opposite to 31b.

  In the present embodiment, the cap member 30 is a plate-like portion that is suspended from the back side plate surface 31 b side of the lid portion 31 with respect to the lid portion 31 as an insertion portion of the insertion portion 10 into the insertion space 10 a. It has an inner support wall 32 and an outer support wall 33. The inner support wall 32 and the outer support wall 33 are plate-like portions that are substantially parallel to each other and face each other. The cap member 30 positions the inner support wall 32 on the inner side in the left-right direction, that is, on the side wall 3x side of the support column 3, and the outer support wall 33 on the outer side in the left-right direction, that is, the outer wide surface portion of the fitting fitting 6 in the mounted state. It is inserted into the insertion portion 10 in a direction to be positioned on the 12 side (see FIG. 11).

  Each part of the cap member 30 will be described. The lid portion 31 is a rectangular plate-like portion having substantially the same shape and dimensions as the opening shape of the opening 10c of the insertion portion 10, and the cap member 30 is fitted into the insertion portion 10 (hereinafter referred to as cap member). 30 is referred to as “fitted state”), and is inserted into the opening 10c with respect to the insertion portion 10, and closes the opening 10c. For this reason, the lid portion 31 exposes the front side plate surface 31a to the outside as an outer plate surface so as to be substantially flush with the opening end surface 10s of the insertion portion 10 when the cap member 30 is fitted. That is, the cap member 30 forms the support surface 6s that forms the support surface 6s that is the mating surface (joint surface) of the pair of ladder bodies 2 with the opening end surface 10s of the insertion portion 10 on the front side plate surface 31a of the lid portion 31. 30 s.

  Specifically, as described above, the insertion portion 10 is configured such that the upper end protrudes slightly above the upper end of the support 3 in a state of being fixed to the support 3. In such a configuration, the lid portion 31 of the cap member 30 is a dimension of the protrusion of the insertion part 10 with respect to the column 3, that is, a dimension of a step between the upper end surface 3 s of the column 3 and the opening end surface 10 s above the insertion part 10. And substantially the same thickness. The lid 31 is locked in a state of being in contact with the upper end surface 3 s of the support column 3 in a state of being inserted into the opening 10 c of the insertion portion 10, and the front side plate surface 31 a is connected to the opening end surface 10 s of the insertion portion 10. It is located on substantially the same plane.

  Here, the inner support wall portion 32 has a direction in which the inner support wall portion 32 and the outer support wall portion 33 face each other with respect to the lid portion 31, that is, a short direction of the rectangular plate-like lid portion 31 (FIG. 15). About (b), it is provided inside slightly, and the level | step difference surface 31c is formed in the edge part of the back side board surface 31b of the cover part 31. As shown in FIG. And the cover part 31 is latched by making the level | step difference surface 31c contact the part of the side wall part 3x of 3s of upper end surfaces of the support | pillar 3 (refer FIG. 11, FIG. 15).

  The inner support wall portion 32 is a substantially rectangular plate-like portion that protrudes substantially perpendicularly from the back-side plate surface 31 b at one end portion in the short side direction of the lid portion 31. The inner support wall 32 has a dimension that is shorter than the dimension of the lid 31 in the longitudinal direction of the lid 31 (vertical direction in FIG. 15D), and excludes both end sides of the lid 31 in the longitudinal direction. It is provided in the middle part.

  The inner support wall portion 32 is a portion along the inner side of the upper end portion of the side wall portion 3x of the support column 3 to which the joint fitting 6 is attached in a state where the cap member 30 is fitted. In other words, the inner support wall 32 brings the outer wall surface 32 a opposite to the outer support wall 33 side into contact with or substantially in contact with the inner surface 3 u of the side wall 3 x of the support column 3 in the fitted state of the cap member 30. .

  For this reason, the inner support wall portion 32 has an end shape protruding from the lid portion 31 so as not to interfere with the flange portion 18 along the inner side surface 3u of the side wall portion 3x inside the treadle through hole 3t. It has an arcuate concave portion 32b. That is, the inner support wall portion 32 has an end shape that follows the arc shape of the collar portion 18 by the concave portion 32b, and in the state where the cap member 30 is fitted, the concave portion 32b extends along the upper side of the collar portion 18, and It will be in the state which covers most of the part by the side of the upper end surface 3s rather than the collar part 18 of the upper end part of the side wall part 3x of the support | pillar 3.

  The outer support wall portion 33 is a substantially rectangular plate-like portion that protrudes substantially perpendicularly from the back-side plate surface 31 b at the other end portion in the short side direction of the lid portion 31. The outer support wall 33 has a dimension slightly shorter than the dimension of the lid 31 in the longitudinal direction of the lid 31, and is provided on substantially the entire longitudinal direction of the lid 31. The outer support wall portion 33 is suspended from the edge on one side of the rectangular plate-shaped lid portion 31 in the short direction. For this reason, the outer wall surface 33 a opposite to the inner support wall portion 32 side of the outer support wall portion 33 is substantially flush with the end surface 31 d on one side in the short side direction of the lid portion 31.

  The outer support wall portion 33 is a portion along the inner side of the outer wide surface portion 12 of the fitting fitting 6 in the mounted state when the cap member 30 is fitted. In other words, the outer support wall 33 brings the outer wall surface 33 a opposite to the inner support wall portion 32 into contact with or substantially in contact with the inner wall surface 12 a of the outer wide surface portion 12 in the fitted state of the cap member 30.

  Further, on the outer wall surface 33 a of the outer support wall portion 33, there is provided a fitting protrusion 34 that fits into the processing hole 12 t of the outer wide surface portion 12 when the cap member 30 is fitted. The fitting protrusion 34 is a disc-shaped portion that protrudes stepwise with respect to the outer wall surface 33a of the outer support wall portion 33, and the protruding portion is substantially the same as the hole shape of the processing hole 12t. When the cap member 30 is fitted, it is provided so as to close the processing hole 12t from the inner side of the insertion part 10.

  The protrusion amount (protrusion dimension) of the fitting protrusion 34 from the wall surface 33a is substantially the same as the wall thickness of the outer support wall 33, and the plate of the outer wide surface portion 12 in which the processing hole 12t is formed. It is almost the same as the thickness. Further, a wall of the outer support wall 33 opposite to the side from which the fitting protrusion 34 protrudes is concentric with the circumferential shape of the fitting protrusion 34 and is slightly smaller than the fitting protrusion 34. A concave portion 33b having a shape is formed. In the present embodiment, the inner support wall is viewed in the direction of the central axis of the fitting protrusion 34, that is, in the direction of the inner support wall 32 and the outer support wall 33 facing each other (see FIG. 15A). The inner support wall portion 32 is provided so that the arc shape of the concave portion 32 b at the protruding end of the portion 32 substantially matches the circumferential shape of the fitting protrusion 34.

  As described above, in the fitting state of the cap member 30, the fitting protrusion 34 that fits into the processing hole 12 t from the inside of the insertion part 10 has an end surface on the protruding side from the processing hole 12 t of the insertion part 10. The exposed surface 34a is exposed to the outside. The exposed surface 34 a is formed as a convex curved surface that slightly bulges with respect to the surface along the outer wall surface 33 a of the outer support wall portion 33 provided so as to form a wall surface perpendicular to the lid portion 31. . Therefore, as described above, the fitting protrusion 34 having the substantially same protruding dimension as the plate thickness of the outer wide surface portion 12 is fitted into the processing hole portion 12t in the fitted state of the cap member 30, and the outer wide surface portion 12 The exposed surface 34a is slightly bulged from the outer wall surface 12b.

  As described above, the cap member 30 according to the present embodiment is fitted into the machining hole 12t from the inside of the insertion portion 10 in a state where the cap member 30 is fitted in the insertion portion 10 at the outer support wall portion 33 thereof. Thus, it has a fitting projection 34 that closes the processing hole 12t. According to such a configuration, the cap member 30 is locked to the fitting 6 in the fitted state by fitting the fitting protrusion 34 to the processing hole 12t, and therefore the fitted cap member 30 is inserted into the fitting portion. It is possible to prevent it from falling off 10 as much as possible.

  Further, the cap member 30 is fitted into the insertion portion 10 in a state where the stepped surface 31 c on the outer side of the inner support wall portion 32 is in contact with the upper end surface 3 s of the column 3 and supported by the column 3. Further, in the fitted state, the cap member 30 is engaged with the insertion hole 10 (joint fitting 6) by fitting the fitting projection 34 into the machining hole 12t, and the joint fitting 6 The relative movement with respect to is restricted. Therefore, the cap member 30 in which the fitting protrusion 34 is fitted into the processing hole 12t restricts the movement of the joint fitting 6 with respect to the column 3 by the rivet 15 or the traverse 4A as described above, that is, This contributes to fixing to the support 3.

  When the cap member 30 in the fitted state is removed from the insertion portion 10, the outer surface is supported by elastic deformation of the cap member 30 by pressing the exposed surface 34 a of the fitting protrusion 34 fitted in the processing hole 12 t. The wall 33 is moved inward to release the fitting state of the fitting protrusion 34 with respect to the processing hole 12t. In this disengaged state, the fitting protrusion 34 is pushed upward (on the lid 31 side), or a tool is used from the gap between the joint fitting 6 and the cap member 30 on the opening end face 10s side of the insertion portion 10. The cap member 30 is removed by floating the cap member 30. Thus, the exposed surface 34a of the cap member 30 serves as a pressing operation surface when the cap member 30 in the fitted state is removed.

  On the other hand, when the cap member 30 is fitted into the insertion portion 10, the cap member 30 is oriented so that the inner support wall portion 32 is on the inner wide surface portion 11 side and the outer support wall portion 33 is on the outer wide surface portion 12 side. It inserts from the opening 10c side with respect to the insertion part 10 from the inner side support wall part 32 and the outer side support wall part 33 side. In the process of fitting the cap member 30 into the insertion part 10, the cap protrusion 30 protrudes from the outer wall surface 33 a of the outer support wall 33. The elastic deformation is temporarily performed so as to be relatively close to the outer support wall 33, and the fitting protrusion 34 reaches the position of the processing hole 12t, whereby the elastic deformation is released, and the fitting protrusion 34 is released. Automatically fits into the processing hole 12t.

  As described above, the cap member 30 is detachably attached to the insertion portion 10 of the joint fitting 6 without using a fixing tool such as a bolt, by fitting and elastic deformation to the insertion portion 10 by the fitting protrusion 34. Fitted and fixed. As the material of the cap member 30, for example, a material that is relatively easily deformed elastically such as a resin material such as plastic and a rubber material such as hard rubber is employed. However, the cap member 30 may be a metal member made of a metal material such as an aluminum alloy.

  Further, in the cap member 30 according to the present embodiment, the exposed surface 34 a of the fitting protrusion 34 is a surface that faces the outside of the insertion portion 10 from the processing hole 12 t in the fitted state of the cap member 30. In view of this, it is appropriate to apply a fluorescent paint / glow paint or a reflector to the exposed surface 34a of the fitting protrusion 34. That is, the exposed surface 34a can be used as a surface for improving the visibility in the nighttime or in a dark place.

  Next, the structure of the opening stop mechanism 8 provided in the ladder and stepladder 1 will be described. The anti-opening mechanism 8 has a half-folded structure composed of two arm parts whose ends are connected to each other so as to be relatively rotatable as described above, and the base part of the anti-opening mechanism 8 serves as two arm parts. It has the 1st metal fitting 41 which comprises the side, and the 2nd metal fitting 42 connected with the one end part of the 1st metal fitting 41. As shown in FIG. Each of the first metal fitting 41 and the second metal fitting 42 is a long and substantially plate-like member, and is provided with respect to the joint fitting 6 so that the plate surface is along the wall surface of the joint fitting 6.

  One end of the first metal fitting 41 is rotatably connected to one of the joint fittings 6 of the pair of joint fittings 6 connected to each other by an attachment screw 43. In the present embodiment, one end portion of the first metal fitting 41 is a side view (for example, see FIG. 8) from one side in the connecting structure on one side in the left-right direction of the ladder-supporting stepladder 1 (left side in FIG. 12). It is connected to a fitting 6A located on the left side. That is, the first metal fitting 41 is pivotally supported on the joint metal fitting 6 by the mounting screw 43 penetrating the first metal fitting 41 and the outer wide surface portion 12 of the joint metal fitting 6 at one end thereof. For this reason, attachment holes 12h and 41h through which the attachment screws 43 pass are formed in the outer wide surface portion 12 of the joint fitting 6 and one end of the first fitting 41, respectively.

  In the present embodiment, the attachment hole 12h is fitted with the rivet hole 11r through which the rivet 15 penetrates and the fitting protrusion 34 of the cap member 30 in the outer wide surface portion 12 in the cylinder axis direction of the insertion portion 10. It is drilled at a predetermined position in the portion between the processing hole 12t. The mounting screw 43 has a cylindrical portion 43a that is not threaded on the head side, supports the first metal fitting 41 in the cylindrical portion 43a, and penetrates the outer wide surface portion 12 in the insertion portion 10. It fixes to the outer side wide surface part 12 with the nut 44a screwed together by the screw part located in (refer FIG. 11). A washer 44b is interposed between the nut 44a and the outer wide surface portion 12.

  One end of the second metal fitting 42 is pivotally connected to the other end of the first metal fitting 41 by a pivot pin 45. That is, the first metal fitting 41 and the second metal fitting 42 can be rotated relative to each other within a predetermined rotation range by the pivot pin 45 penetrating the portion where the ends of the first metal fitting 41 and the second metal fitting 42 overlap each other. Connected. Therefore, pivot holes 41j and 42j through which the pivot pins 45 penetrate are formed in the other end portion of the first metal fitting 41 and one end portion of the second metal fitting 42, respectively. In the present embodiment, the second metal fitting 42 is provided in a state where one end of the first metal fitting 41 is overlapped on the inner side (the fitting metal fitting 6 side) with respect to the other end of the first metal fitting 41.

  The other end of the second metal fitting 42 is latched and supported by the other metal fitting 6 of the pair of metal fittings 6 connected to each other. In the present embodiment, the other end of the second metal fitting 42 is a side view (for example, see FIG. 8) from one side in the connecting structure on one side in the left-right direction of the ladder-supporting stepladder 1 (left side in FIG. 12). And is supported by the joint fitting 6B located on the right side. The other end portion of the second metal fitting 42 is supported in a state of being engaged with a locking projection 46 protruding from the outer wall surface 12 b of the outer wide surface portion 12 of the other fitting metal fitting 6.

  The locking projection 46 is provided on the outer wide surface portion 12 with the same configuration as the mounting screw 43 that pivotally supports one end portion of the first metal fitting 41. That is, the locking protrusion 46 is formed by the nut 47a and the washer 47b in a state where the locking screw 46A similar to the mounting screw 43 projects the outer wide surface portion 12 through the mounting hole 12k so that the head side protrudes from the wall surface 12b. The configuration is fixed to the outer wide surface portion 12. The locking screw 46A has a cylindrical portion 46a that is not threaded on the head side, and this cylindrical portion 46a is positioned outside the wall surface 12b, and the other end of the second metal fitting 42 is connected to the cylindrical portion 46a. To support.

  The mounting hole 12k through which the locking screw 46A that constitutes the locking projection 46 in the outer wide surface portion 12 passes is symmetrical with the mounting hole 12h of the mounting screw 43 in one of the joint metal fittings 6 in the pair of joint metal fittings 6 connected to each other. It is provided at a proper position. That is, the pivot support position on one end side of the first metal fitting 41 that is one end side of the connection mechanism of the first metal fitting 41 and the second metal fitting 42 that constitutes the locking mechanism 8 and the second end that is on the other end side of the connection mechanism. The support position on the other end side of the metal fitting 42 is provided at a symmetrical position in the pair of joint metal fittings 6.

  In order to engage with such a locking protrusion 46, the second metal fitting 42 has a substantially “U” shape in which the other end is open on one side in the short direction (the lower side in FIG. 16A). Has a notch recess 42a. The second metal fitting 42 engages with the locking projection 46 from the open side of the notch recess 42a by rotation or the like using the mounting screw 43 in a straight line with the first metal fitting 41 as a shaft support portion. In this embodiment, in the stepladder combined ladder 1, the first bracket 41 and the second bracket 42 are in a straight line, and the lower side in a state of being laid in a substantially horizontal direction between the pair of ladder bodies 2, Since it becomes the open side of the notch recessed part 42a, the 2nd metal fitting 42 will be engaged with the latching protrusion 46 from the upper side in the ladder-ladder 1 in the stepladder state. The locking projection 46 has the cylindrical portion 46a positioned in the notch recess 42a, and the second metal fitting in a state in which the head 46b having an outer diameter larger than the width of the notch recess 42a is engaged with the locking projection 46. 42, the movement of the second metal fitting 42 in the engaged state in a direction away from the joint fitting 6 is restricted.

  The engagement state of the second metal fitting 42 with respect to the locking protrusion 46 is locked and supported by a locking plate 48 provided in the opening preventing mechanism 8. The locking plate 48 is a substantially rectangular plate-like member as a whole, and is provided so as to overlap the front side (outside) of the second metal fitting 42. The locking plate 48 is positioned by a peripheral wall portion 42c or the like formed so as to stand on the front side (outside) along the peripheral edge of the second metal fitting 42, and a support protrusion protruding from the front side surface of the second metal fitting 42 It is supported in a state of passing through 42d. The locking plate 48 penetrates the support protrusion 42d at a substantially central position in the longitudinal direction and the short direction.

  A locking hole 48a is formed at one end of the locking plate 48 in the longitudinal direction to allow the locking projection 46 engaged with the notch recess 42a to pass therethrough. The second metal fitting 42 is rotatable with respect to the joint metal fitting 6 when the engagement protrusion 46 passes through the engagement hole 48a of the engagement plate 48 and is engaged with the engagement protrusion 46 by the notch recess 42a. Supported. In other words, the movement of the second metal fitting 42 in the direction away from the joint metal fitting 6 as described above is restricted by the head 46b of the locking protrusion 46 with the other end being locked to the locking protrusion 46. The movement (sliding movement) in the direction along the outer wall surface 12b of the outer wide surface portion 12 is restricted by passing the locking protrusion 46 through the locking hole 48a of the locking plate 48, so that And supported so as to be relatively rotatable.

  Further, the locking plate 48 is pressed in the direction pressed against the second metal fitting 42 by the coil spring 49 fitted on the support protrusion 42d, that is, in the direction close to the second metal fitting 42 (upward in FIG. 16B). It is provided in an energized state. The coil spring 48 is interposed between a front side (outside) surface of the locking plate 48 and a head provided at an end of the support projection 42d on the protruding side in a state where the support projection 42d is penetrated. ing.

  Thus, in the locking plate 48 provided in a state of being urged by the coil spring 49, a pressing piece portion 48b is provided at the end of the other side in the longitudinal direction (opposite side to the locking hole 48a). It has been. That is, the pressing protrusion 48b positions the support protrusion 42d penetrating the locking plate 48 between the pressing hole 48a. The pressing piece 48b is separated from the front side (outer) surface 42e of the second metal fitting 42 in the locking plate 48 provided in contact with the second metal fitting 42 on the front side (outer side) of the second metal fitting 42. In other words, it is provided in a step shape with respect to the other portions of the locking plate 48 so as to have a predetermined interval.

  The locking plate 48 corresponds to the open side of the notch recess 42a at the end on the side where the locking hole 48a is provided and supported by the second metal fitting 42 in the short direction of the locking plate 48. It has a projecting piece portion 48d protruding to the side. The projecting piece portion 48d has a substantially “T” shape, and projects through an arch portion 42g provided at an end portion of the second metal fitting 42 that is supported by the locking projection 46.

  In addition, the range of relative rotation between the first metal fitting 41 and the second metal fitting 42 that are connected so as to be capable of relative rotation is from the rotation position where the first metal fitting 41 and the second metal fitting 42 are in a straight line. At least the range up to the turning position where the ladder-supporting stepladder 1 is bent in a substantially inverted “V” shape in the folded state as described above. At the rotational position where the first metal fitting 41 and the second metal fitting 42 are in a straight line, the peripheral wall portion 42c provided on one side of the second metal fitting 42 in the short direction (upper side of the ladder-supporting stepladder 1 in the stepladder state). Becomes a stopper for the first metal fitting 41, and further relative rotation between the first metal fitting 41 and the second metal fitting 42 (in a direction opposite to the direction in which the metal fitting is folded in the folded state) is restricted.

  As described above, the opening preventing mechanism 8 of the present embodiment has one end fitting, that is, one end of the first fitting 41, that is, the end opposite to the connection side of the first fitting 41 with respect to the second fitting 42, by the mounting screw 43. 6 is provided in a state of being pivotally supported at a predetermined position in FIG. In the ladder-ladder stepladder 1 in the stepladder state, the other end of the locking mechanism 8, that is, the end opposite to the connection side of the second bracket 42 with respect to the first bracket 41 is provided in the other joint bracket 6. By engaging the notch recess 42 a with the engaging protrusion 46, the engaging protrusion 46 is engaged and supported at a predetermined position on the other fitting 6. As a result, the opening prevention mechanism 8 is in a state of being stretched between the support columns 3 in a linear manner along the horizontal direction on both the left and right sides of the ladder-supporting stepladder 1, and has a substantially inverted “V” shape in a side view. The opening of the ladder bodies 2 in the downwardly opened state that is opened by a predetermined amount is stopped.

  According to the locking mechanism 8 of the present embodiment, the pressing piece 48 b approaches the outer surface 42 e of the second metal fitting 42 by pressing the pressing piece 48 b of the locking plate 48, and the locking plate 48. However, it operates like a seesaw against the urging force of the coil spring 49, and the side opposite to the pressing piece 48 b, that is, the side of the locking hole 48 a is lifted from the second metal fitting 42. As a result, the locking state of the locking plate 48 with respect to the locking protrusion 46 due to the locking protrusion 46 passing through the locking hole 48 a is released, and the opening preventing mechanism 8 is not connected to the locking protrusion 46 of the second metal fitting 42. A state where engagement and release thereof are possible, that is, a state where attachment to and detachment from the locking projection 46 is possible. That is, in such a state, a gap is formed between the end of the locking plate 48 on the side of the locking hole 48a and the other end of the second metal fitting 42, and the engagement engaged with the notch recess 42a by the gap. A path through which the stop protrusion 46 can pass including the head portion 46 b is secured, and the second metal fitting 42 can be attached to and detached from the locking protrusion 46.

  In such an attaching / detaching operation of the second metal fitting 42 with respect to the locking protrusion 46, the substantially “T” -shaped protruding piece portion 48 d of the locking plate 48 is attached to the locking protrusion 46 of the second metal fitting 42. At this time, the back side receives pressure from the locking projection 46 and guides the insertion of the locking projection 46 into the locking hole 48a. Further, the projecting piece portion 48d also functions as an operation portion for making the end portion of the second metal fitting 42 attachable to and detachable from the locking projection 46 instead of the pressing piece portion 48b. In this case, the second metal part 42 can be attached to and detached from the locking projection 46 by lifting the projecting piece part 48 d so as to float from the second metal part 42. With regard to the operation of the protruding piece portion 48d, the arch portion 42g for allowing the protruding piece portion 48d to dive functions as a receiving portion that receives the contact of the protruding piece portion 48d.

  As a mode of use of the ladder-supporting stepladder 1, in the deformation between the ladder state and the stepladder state or the folded state, a pivotal support portion for the locking projection 45 of the second metal fitting 42 in the opening preventing mechanism 8. Is once removed. On the other hand, the deformation between the stepladder state and the folded state is the same as the linear state of the locking mechanism 8 while the supporting state of the shaft support portion with respect to the locking projection 45 of the second metal fitting 42 in the locking mechanism 8 is maintained. It is performed with deformation between the bent state.

[Manufacturing method of fittings]
An example of the manufacturing method of the joint fitting 6 according to the present embodiment will be described with reference to FIG. As shown in FIG. 17, first, a rectangular tubular pipe part 110 and a plate-like part 120 projecting vertically from an outer wall surface 113 a on one side of the pipe part 110 by extrusion molding using aluminum or an aluminum alloy as a material. A process (extrusion molding process) for forming an extruded shape member 106 that is an extrusion molded product having the above is performed.

  In the extruded shape member 106, the pipe portion 110 is a portion that constitutes the insertion portion 10 in the joint fitting 6, and the plate-like portion 120 is a portion that constitutes the hinge portion 20 in the joint fitting 6. is there. Accordingly, the four wall portions 110a, 110b, 110c, and 110d that constitute the rectangular tubular pipe portion 110 are opposed to the inner wide surface portion 11 and the outer wide surface portion 12 that are the portions that constitute the insertion portion 10 in the fitting 6. Corresponding to each of the narrow side surface portion 13 and the non-facing narrow surface portion 14, the plate-like portion 120 projects from the wall portion 110 c corresponding to the facing narrow surface portion 13.

  Further, as described above, in the joint fitting 6, the hinge portion 20 has a plate surface on one side with respect to the insertion portion 10, and the opposing direction of the inner wide surface portion 11 and the outer wide surface portion 12 in the insertion portion 10 ( The hinge portion 20 is provided so as to substantially coincide with the center position (see FIG. 14A, straight line M1). For this reason, in the extruded shape member 106, the plate-like portion 120 is provided at a position slightly shifted from the center in the width direction of the wall portion 110c. That is, the plate-like portion 120 substantially matches the plate surface 120a on one side with the center position (see the straight line N1) in the width direction of the wall portion 110c (the plate thickness direction of the plate-like portion 120) with respect to the pipe portion 110. It is provided as follows.

  Next, the extruded shape member 106 is cut into a predetermined length P1 that is substantially the same length as the overall length of the joint fitting 6 (in the cylinder axis direction of the insertion portion 10), and the cut molded product 106A is cut. A step of forming (cutting step) is performed. The cut-out molded product 106A includes a cylindrical portion 110A and a protruding piece portion 120A in which the pipe portion 110 and the plate-like portion 120 in the extruded shape member 106 have a length P1, respectively. Here, the length P1 of the cut-out molded product 106A is a hinge that protrudes the shaft support portion 23 from the insertion end portion 10 and the opening end face 10s side of the insertion portion 10 in the cylinder axis direction of the insertion portion 10 in the fitting 6. The length includes the portion 20.

  Subsequently, a step (first excision step) of cutting a part of the cylindrical portion 110A into a slit shape is performed on the cut molded product 106A. In this step, in the cylindrical portion 110A, the cylindrical shape is obtained by a predetermined process such as pressing or cutting so that an end face 110s to be the opening end face 10s of the fitting part 10 of the fitting 6 is formed as a cut end face. The portion 110A is partially cut with a very short dimension in the cylinder axis direction (see the hatched portion Q1). That is, in the cut-out molded product 106A, the portion of the cylindrical portion 110A on one of the cut end faces 110t becomes the lower open end face of the joint fitting 6, and becomes the open end face 10s in relation to the cut end face 110t. The position where the end surface 110s is to be formed is partially cut away, so that the length of the portion that finally forms the insertion portion 10 of the fitting 6 is defined in the cylindrical portion 110A.

  Therefore, according to this step, a slit-shaped gap 110u is formed in the cut-out portion of the cylindrical portion 110A, and the cylindrical portion 110A is finally inserted into the fitting portion 10 of the fitting 6 by the gap 110u. The first cylindrical portion 110B and the second cylindrical portion 110C to be cut later are divided. The length P2 of the first tubular portion 110B in the tube axis direction corresponds to the length of the insertion portion 10 of the fitting 6 in the tube axis direction. The processed product obtained in the first excision step is referred to as a first excised product 106B.

  Next, in order to cut out the final outer shape of the joint fitting 6 from the first cut-out molded product 106B, a step of cutting out the second cylindrical portion 110C and a predetermined portion of the protruding piece portion 120A (second cut-out step). Is done. In this process, with respect to the cylindrical part, the second cylindrical part 110C formed in the first excision process is excised (see the hatched part Q2), and the final hinge part 20 is formed in the projecting piece part 120A. Parts other than the part to be cut are excised.

  Specifically, on one side in the longitudinal direction of the projecting piece portion 120A (the second cylindrical portion 110C side), the corner portions 120a and 120b (following the outer shape of the shaft support portion 23 projecting in a semicircular shape at the hinge portion 20). The hatched portions Q3 and Q4) are excised. In addition, a circular portion 120c (see hatched portion Q5) is cut out in order to form the shaft support hole 24 in the central portion of the virtual circumference along the semicircular shape of the shaft support portion 23. Further, on the other side in the longitudinal direction of the projecting piece 120A, a substantially triangular portion 120d (see hatched portion Q6) along the inclined shape of the inclined portion 22 in the hinge portion 20 is cut off.

  In such a second excision step, excision processing for the first excision molded product 106B, that is, excision processing of the second cylindrical portion 110C, and the corner portions 120a and 120b, the circular portion 120c, and the substantially triangular shape in the projecting piece portion 120A. The excision of the shape portion 120d is performed at the same time or stepwise in a predetermined order by a predetermined process such as pressing or cutting. By the second excision step, the outer shape of the insertion part 10 and the hinge part 20 in the final fitting 6 is defined in the processed product. The processed product obtained in the second excision step is referred to as a second excision molded product 106C.

  Subsequently, with respect to the second cut-out molded product 106C, the treadle through hole 11t and the rivet hole 11r that the inner wide surface portion 11 has in the joint fitting 6 and the processing hole portion 12t and the attachment hole 12h that the outer wide surface portion 12 have. A step of forming each of the holes (a perforating step) is performed. In this step, first, the processing hole 12t and the attachment hole 12h are formed in the side wall 112a corresponding to the outer wide surface portion 12 in the second cut-out molded product 106C. Next, in the second cut and formed product 106C, a treadle through hole 11t and a rivet hole 11r are formed in the side wall portion 111a corresponding to the inner wide surface portion 11.

  In this drilling step, each hole is drilled by pressing or cutting using a die such as a punch. In addition, as the order of forming each hole, after forming the traverse through hole 11t and the rivet hole 11r in the side wall 111a, the processing hole 12t and the mounting hole 12h are formed in the side wall 112a. Also good. Moreover, about formation of the hole in each side wall part 111a, 112a, a some hole may be formed simultaneously and may be formed in a predetermined order.

  As described above, in an example of the manufacturing method of the joint fitting 6 according to the present embodiment, from the extrusion molding process in which the extruded shape member 106, which is an extrusion molding product made of an aluminum material, is formed as a starting member, the cutting process, the cutting process ( The joint metal fitting 6 is manufactured through the first excision step and the second excision step) and the drilling step. In addition, about each of a pair of joint metal fittings 6 mutually connected, although it becomes a common processed product from the extrusion shape member 106 which is a starting member to the 2nd cutting molded product 106C obtained by the 2nd cutting process, it is a hinge. Since the inner wide surface portion 11 and the outer wide surface portion 12 are opposite to each other in relation to the portion 20, the treadle through hole 11t and the rivet hole 11r, and the processing hole portion 12t and the mounting hole 12h are opposite to each other. It will be formed on the side wall portion on the side.

  Moreover, in this embodiment, the connection structure including a pair of joint metal fittings 6 for connecting the columns 3 to each other on the left and right sides of the ladder-supporting stepladder 1 is configured symmetrically as described above (see FIG. 12). In such a configuration, with respect to the pair of joint fittings 6 constituting the connecting structure on the opposite side in the left-right direction of the ladder-supporting stepladder 1, the width direction of the opposing narrow side surface portion 13 of the insertion portion 10 (the hinge portion 20 The direction of deviation from the center position of the hinge portion 20 in the (thickness direction) is the opposite side.

[Method of manufacturing ladder connecting structure]
An example of the manufacturing method of the connection structure of the ladder body 2 according to the present embodiment will be described with reference to FIG. As shown in FIGS. 18A and 18B, first, a process of attaching the fitting 6 to the upper end portion of each column 3 and fixing it to the column 3 with the rivet 15 is performed. In the present embodiment, the rivets 15 are provided at two positions near the lower side of the inner wide surface portion 11 of the insertion portion 10 (see FIG. 13A), and the side wall portion 3x of the column 3 and the insertion portion 10 are inserted. The rivet holes 3r and 11r formed in each of the inner wide surface portions 11 penetrate the side wall portion 3x and the inner wide surface portion 11 in a state of being overlapped with each other.

  Next, as shown in FIG. 18 (c), a step of fixing the uppermost step rail 4 </ b> A to the upper end portion of the support column 3 to which the fitting 6 is attached is performed. In this step, as described above, the cylindrical workpiece to be processed as a protruding portion from the first clamping surface 17u on both ends in the longitudinal direction in a state before the step 4A is processed (before fixing) is a punch or the like. By the pressing mold, the left and right support columns 3 are compressed and deformed in a state of protruding outward in the left-right direction via the step-through through holes 3t, 11t. As a result, the flange portion 18 is formed, and the joint fitting 6 and the tread bar 4 </ b> A are caulked and fixed to the column 3.

  In this way, by using the pressing die, the flange portion 18 is formed by compressive deformation of the cylindrical workpiece to be protruded outward in the left-right direction through the treadle through holes 3t and 11t, and the treads associated therewith. A processing step is performed in which the post 3 and the fitting 6 are fixed by caulking with the crosspiece 4A. In this process, the cylindrical covering of the step rail 4A that protrudes from the step through-holes 3t and 11t and is located inside the joint fitting 6 by the processing hole 12t formed in the outer wide surface portion 12 of the joint fitting 6. A pressing path such as a punch that acts on the processed portion is secured.

  Then, after the tread bar 4A is fixed to the column 3, as shown in FIGS. 18C and 18D, a step of fitting the cap member 30 into the insertion portion 10 from the upper opening 10c is performed. . Here, as described above, the cap member 30 has an opening 10c with respect to the insertion portion 10 with the inner support wall portion 32 on the inner wide surface portion 11 side and the outer support wall portion 33 on the outer wide surface portion 12 side. With the elastic deformation, the fitting protrusion 34 is automatically fitted into the machining hole 12t and attached to the insertion portion 10. When the cap member 30 is attached to the insertion portion 10, the opening 10 c on the upper side of the insertion portion 10 is closed by the lid portion 31 of the cap member 30, and the fitting protrusion provided on the outer support wall portion 33. By the part 34, the processing hole 12t formed in the outer wide surface part 12 of the insertion part 10 is closed from the inner side.

  Subsequently, the first joint bracket 6A and the second joint bracket 6B, which are joint brackets 6 that are located on the same side in the left-right direction and are fixed to the pillars 3 constituting the ladder bodies 2 different from each other in the ladder-ladder 1 are used. Are connected to each other so as to be rotatable. That is, the first joint fitting 6A and the second joint fitting 6B connect the hinge portions 20 to each other so as to be rotatable with the bolts 25 and the like. And the opening prevention mechanism 8 is provided between a pair of joint fittings 6 mutually connected.

  As described above, in the example of the method for manufacturing the connecting structure of the ladder body 2 according to the present embodiment, the step of fixing the joint fitting 6 to the support column 3 and the fixing of the footrail 4A to the support column 3 via the joint fitting 6 A step of attaching the cap member 30, a step of connecting the pair of joint fittings 6 to each other, and a step of providing the opening prevention mechanism 8.

  According to the ladder combined stepladder 1 according to the present embodiment described above, with respect to the joint fitting 6 for connecting the ladder bodies 2 to each other so as to be rotatable, a simple structure can provide sufficient load resistance when using the ladder. It is possible to easily reduce the weight.

  When the ladder of the ladder-ladder 1 is used, a very large load is applied to the joint fitting 6 whose upper ends are joined to each other. In the configuration in which the plate-shaped fitting is fixed with the plate surface along the outer side surface of the upper end of each column as in the prior art, such a load is fixed to a rivet or the like that fixes the coupling to the column. It acts as a shearing force directly on the member. For this reason, about fixing members, such as a rivet which fixes a joint metal fitting to a support | pillar, a considerable fixed strength is required and the number corresponding to it is required. A large number of fixing members such as rivets increases the number of parts of the ladder and stepladder and increases the number of manufacturing steps. In addition, in the conventional joint fitting, from the viewpoint of preventing the lateral displacement between the joint fittings as described above, deformation of the joint fitting, etc., it is necessary to ensure a considerable degree of strength for the joint member itself. Steel members are used as the fittings. The steel member is relatively heavy, and causes the weight of the ladder and stepladder to be increased.

  Therefore, according to the ladder-supporting stepladder 1 according to the present embodiment, the joint metal fitting 6 includes the insertion portion 10 into which the upper end portion of the column 3 is inserted, and the hinge portion 20 which is a portion connected to each other. Since the insertion surface 10 is provided with a structure that forms a support surface 6s that is a mating surface with respect to the joint metal fitting 6 to be connected, a large load is applied to the metal joint 6 in which the upper ends are joined to each other when the ladder is used. Can be received via the support surface 6s including the opening end surface 10s of the insertion fitting portion 10 of the fitting fitting 6 that is externally fitted. That is, with respect to the contact support structure between the joint fittings when the ladder is used, in the conventional technique, the ladder-supporting stepladder 1 according to the present embodiment has the support column 3 of the support structure in which the plate-like joint fittings are in a so-called line contact. A surface contact support structure is formed by the support surface 6s having a substantially rectangular outer shape including the outer shape of the upper end surface.

  Thereby, when using the ladder, the load acting on the fixing member such as the rivet 15 for fixing the joint fitting 6 to the support column 3 can be reduced while obtaining sufficient load resistance, and the fixing member such as the rivet can be reduced. Can be reduced as much as possible. As a result, the number of parts of the ladder / ladder 1 can be reduced, so that a simple configuration can be realized and the number of manufacturing steps can be reduced.

  Further, according to the support structure of the surface contact by the support surface 6s formed by the cylindrical insertion part 10, the load at the time of using the ladder can be dispersed in comparison with the support structure of the line contact. The strength required for 6 itself can be reduced. As a result, a relatively light material such as aluminum or aluminum alloy can be used as the material of the joint fitting 6, so that the weight of the connecting structure of the ladder body 2 can be reduced. The overall weight can be reduced. The material of the joint fitting 6 is not limited to aluminum or aluminum alloy as in the present embodiment, but may be other metal materials or resin materials. From the viewpoint, aluminum or an aluminum alloy is preferably used.

  Moreover, in the ladder combined stepladder 1 according to the present embodiment, together with the insertion portion 10 of the joint metal fitting 6, it is mounted on the insertion portion 10 as a member that forms a support surface 6 s that receives a load as a mating surface when the ladder is used. A cap member 30 is provided. In other words, the ladder-supporting stepladder 1 is fitted into the insertion portion 10 that opens both sides of the insertion space 10a in the cylinder axis direction from the opening 10c opposite to the insertion port 10b of the insertion space 10a, together with the insertion portion 10. A cap member 30 that forms the support surface 6s is provided.

  According to such a configuration, the load received on the support surface 6 s when the ladder is used can be received by the cap member 30 in addition to the joint fitting 6. Thereby, the load at the time of ladder use can be disperse | distributed to the joint metal fitting 6 and the cap member 30, and intensity | strength required about the joint metal fitting 6 itself can further be reduced. Therefore, it is possible to reduce the number of fixing members such as the rivets 15 for fixing the joint fitting 6 to the column 3 and to reduce the weight of the joint fitting 6 effectively.

  Moreover, in the ladder combined stepladder 1 according to the present embodiment, a configuration is adopted in which the joint fitting 6 is fixed to the support column 3 while being fastened together with the uppermost step rail 4A. According to such a configuration, it is possible to improve the fixing strength of the joint fitting 6 to the support column 3. As a result, it is possible to easily secure the fixing strength of the joint fitting 6 to the column 3 and to effectively reduce the load acting on the fixing member such as the rivet 15 when the ladder is used. The number of members can be reduced as much as possible, and the structure can be simplified.

  Further, in the ladder-supporting stepladder 1 according to the present embodiment, in the joint metal fitting 6, the hinge portion 20 has a plate surface on one side with respect to the insertion portion 10, and the width of the opposing side narrow surface portion 13 in the insertion portion 10. It is provided with a configuration in which it is provided so as to substantially coincide with the center position in the direction (plate thickness direction of the hinge portion 20). According to such a configuration, the position of the mating surface where the pair of joint fittings 6 that are coupled to each other joins the hinge portions 20 is positioned at the approximate center of the insertion portion 10 in the thickness direction of the hinge portion 20.

  Thereby, since the position of the insertion fitting part 10 in the left-right direction of the ladder-supporting stepladder 1 can be set to a common position with respect to the pair of joint brackets 6 connected to each other, the ladder body 2 including the pair of joint brackets 6 can be used. The connecting structure can be made compact. Moreover, since the position of the insertion part 10 in the left-right direction of the ladder / ladder 1 can be set to a common position, the support surfaces 6s serving as mating surfaces when using the ladder can be brought into full contact with each other. . As a result, when the ladder is used, the load applied to the support surface 6s can be evenly distributed over the entire support surface 6s, and the load on the joint fitting 6 can be effectively reduced.

  In addition, in the ladder-supporting stepladder 1 according to the present embodiment, the insertion portion 10 constituting the joint metal fitting 6 follows the outer shape of the cross section of the support column 3 and has one side in the cylinder axis direction of the insertion port 10b of the support column 3. It is comprised as a cylindrical part which forms the insertion space 10a opened as. According to such a configuration, the joint fitting 6 can firmly surround the support column 3 having a U-shaped cross-sectional shape over the entire circumference by the insertion portion 10 in the mounted state. The support surface 6s serving as a mating surface when the ladder is used is formed by the opening end surface 10s of the insertion portion 10 surrounding the support column 3 over the entire circumference. As a result, it is possible to easily ensure the support strength when the ladder is used in the joint fitting 6, that is, the load resistance.

  In addition, since the insertion portion 10 of the fitting 6 is a cylindrical part, the support column 3 is provided with the open side of the U-shaped cross-sectional shape facing the left and right outer sides, The left and right outer wall surfaces of the insertion portion 10, that is, the outer wide surface portion 12 can be used as a portion that supports the opening prevention mechanism 8. For this reason, it is not necessary to perform a process for providing the opening preventing mechanism 8 in the support column 3 or to separately provide a member for supporting the opening preventing mechanism 8, and the structure can be simplified.

  Further, in the ladder combined stepladder 1 according to the present embodiment, the insertion hole 10 of the joint fitting 6 is provided with a processing hole 12t for fixing the step rail 4A to the support column 3. A fitting protrusion 34 that fits into the processing hole 12t is provided. According to such a configuration, as described above, the cap member 30 in the fitted state can be prevented from falling off from the insertion part 10 as much as possible. In addition, since the cap member 30 is fitted into the insertion portion 10 while being supported by the support column 3 as described above, the cap member 30 is used to fit the fitting protrusion 34 to the processing hole portion 12t. The fixing of 6 to the support 3 is reinforced. This contributes to reducing the load acting on the fixing member such as the rivet 15 when the ladder is used.

  Further, in the configuration in which the exposed surface 34a of the fitting protrusion 34 is exposed to the outside of the insertion portion 10 from the processing hole 12t in a state where the cap member 30 is mounted on the insertion portion 10, as described above, Applying a fluorescent paint or luminescent paint or attaching a reflector to the exposed surface 34a is appropriately performed. According to such a configuration, for example, when the ladder-supporting stepladder 1 is used for work at night or in a dark place, the left and right sides of the upper end portion of the ladder body 2 are positioned close to the height of the human eye. The visibility of the position of the part can be improved. Thereby, at the time of work at night or in a dark place, for example, the operator can easily recognize the use state (ladder state / ladder state) of the ladder / ladder 1 or the presence of the ladder / ladder 1 itself. It is possible to improve work safety.

  About the structure of the ladder combined stepladder which concerns on this invention, it is not limited to the structure of the ladder combined stepladder 1 which concerns on embodiment mentioned above, A various aspect is employable in the range along the meaning of this invention.

  In the ladder-supporting stepladder 1 according to the above-described embodiment, the insertion part 10 constituting the joint metal fitting 6 has a structure in which both sides in the cylinder axis direction are opened, but the insertion part 10 is inserted into the column 3. The structure which opened only the opening | mouth 10b side may be sufficient. As such a configuration, for example, the side opposite to the insertion port 10b in the insertion portion 10 is closed by a surface portion perpendicular to the cylinder axis direction of the insertion portion 10, and the surface portion serves as a mating surface when the ladder is used. The structure in which a surface is formed is mentioned. In such a configuration, the cap member 30 can be omitted.

  Thus, as the insertion fitting part 10 which comprises the joint metal fitting 6, what is necessary is just the part which forms the insertion space 10a of the support | pillar 3 which opened at least one side of the cylinder axis direction as the insertion port 10b of the support | pillar 3. However, according to the configuration in which the insertion portion 10 opens both sides in the cylindrical axis direction as in the above-described embodiment, the starting member is an extrusion-molded product, for example, as in the above-described method of manufacturing the fitting 6. By adopting a process in which a certain extruded shape 106 is formed and this extruded shape 106 is cut at a predetermined length, the joint fitting 6 can be easily mass-produced. Moreover, since the thickness of the portion of the insertion portion 10 that forms the support surface 6 s can be easily adjusted by manufacturing the joint fitting 6 from an extruded product, the support strength (load resistance) of the joint fitting 6 can be adjusted. Property) can be easily secured.

  In the ladder ladder stepladder 1 according to the above-described embodiment, the connection structure including the pair of joint fittings 6 that connect the support columns 3 to each other on the left and right sides is configured symmetrically as described above (see FIG. 12). However, the present invention is not limited to this, and the connection structure may have a point-symmetric configuration as shown in FIG. 19, for example. That is, in the configuration shown in FIG. 19, for example, the arrangement relationship between the pair of joint fittings 6 in a side view from one side (left side in FIG. 19) of the ladder-standing stepladder 1 in the left-right direction is the same as The arrangement relationship of the pair of fittings 6 in a side view from the other side in the left-right direction (the right side in FIG. 19) is common to each other.

  In the example shown in FIG. 19, in the side view from either the left or right side, of the pair of joint fittings 6 connected to each other, the joint fitting 6 located on the left side is the first joint fitting 6A, and the joint fitting located on the right side When 6 is the second joint metal fitting 6B, the first joint metal fitting 6A has an arrangement relationship in which the hinge part 20 is positioned on the inner side in the left-right direction with respect to the hinge part 20 of the second joint metal fitting 6B. (See FIG. 8). According to such a configuration, for all (four) joint fittings 6 provided in the ladder-supporting stepladder 1, the process from the extrusion process to the second resection process for obtaining the second resection product 106 </ b> C is made common. It becomes possible to plan. Thereby, the manufacturing process can be simplified.

  In the case of adopting the configuration shown in FIG. 19, since the arrangement relationship of the pair of joint fittings 6 is common to the left and right, even the joint fitting 6 after being drilled by the drilling process can be used as a ladder. The four joint fittings 6 used for the stepladder 1 are only two types, two first joint fittings 6A and two second joint fittings 6B. On the other hand, as shown in FIG. 12, when the connection structure including the pair of joint fittings 6 that connect the columns 3 on the left and right sides is symmetrical, the center position of the hinge portion 20 with respect to the insertion portion 10. And the difference in the direction of deviation from the difference between the positions where the various hole portions are formed in relation to the side on which the hinge portion 20 of the pair of joint fittings 6 connected to each other is provided. There are four types of joint fittings 6.

  Moreover, in the ladder combined stepladder 1 according to the above-described embodiment, the support column 3 having a “U” -shaped cross-sectional shape has the open side of the “U” -shaped cross-sectional shape facing the left and right outer sides. However, as shown in FIG. 20, it may be provided with the open side of the “U” -shaped cross-sectional shape facing the left and right inner sides. In this configuration example, the insertion portion 10 is externally fitted to the column 3 with respect to the column 3 having a U-shaped cross-sectional shape by the side wall portion 3x and the pair of end wall portions 3y facing each other. In this state, the outer wide surface portion 12 is along the side wall portion 3x, the opposing side narrow surface portion 13 and the non-opposing side narrow surface portion 14 are along the end wall portion 3y, and the inner wide surface portion 11 is along the side wall portion 3x. It will be in the state of facing.

  In this configuration example, the portion of the outer wide surface portion 12 along the side wall portion 3 x of the column 3 is fixed to the side wall portion 3 x of the column 3 by the rivet 15. Therefore, the outer wide surface portion 12 is provided with a rivet hole 12r for allowing the rivet 15 to pass through together with the rivet hole 3r of the side wall portion 3x. Also, in this configuration example, although not shown, for example, the opening prevention mechanism 8 provided between the support columns 3 connected to each other on both the left and right sides via the joint fittings 6 is a pair of joint fittings connected to each other. 6 in the left-right direction. That is, the first metal fitting 41 and the second metal fitting 42 constituting the opening preventing mechanism 8 are supported by the inner wide surface portion 11 of the insertion portion 10. For this reason, the inner wide surface portion 11 is appropriately provided with a hole for attaching a member constituting the opening preventing mechanism 8.

DESCRIPTION OF SYMBOLS 1 Ladder combined stepladder 2 Ladder body 3 Prop 4 Foot cross 4A Foot cross 6 Joint metal fitting (joint member)
6s support surface 10 insertion part 10a insertion space 10b insertion port 10c opening 10s opening end face 12 outer wide surface part 12t hole for processing 20 hinge part 20a plate surface 20b plate surface 30 cap member 34 fitting protrusion

Claims (4)

A pair of ladder bodies each having a pair of support columns, which are vertical members, and a step rail horizontally mounted between the pair of support columns, and the pair of ladder bodies are rotated with the installation direction of the step rail as a rotation axis direction. A ladder-coupled stepladder that is movably connected,
The struts provided on the upper ends of the struts constituting the ladder body and connected to each other on the same side in the construction direction of the pair of ladder bodies are rotated with the construction direction as the rotation axis direction. It has a joint member that can be movably connected,
The joint member is
The other party that is fixed to the column with the upper end of the column inserted, and is connected in a state where the rotation angle of the pair of ladder bodies is the maximum rotation angle at which the pair of ladder bodies form a ladder state. An insertion portion that forms a support surface that supports a load in a direction in which the pair of ladder bodies opens as a mating surface with respect to the joint member;
It protrudes from a side surface of the insertion portion, and a hinge portion connected to the catch member of the counterpart, was closed,
The insertion portion is a cylindrical portion that forms an insertion space of the support column that is open along both sides in the cylinder axis direction along the outer shape of the cross section of the support column and has a closed cross section. The stepladder stepladder is characterized by forming the support surface . The hinge portion is a plate-shaped portion in which the erection direction is a plate thickness direction in a state where the joint member is mounted on the support column,
The hinge portion of each of the pair of joint members connected to each other is provided so that a plate surface on one side substantially coincides with a center position in the plate thickness direction of the insertion portion. The ladder and stepladder according to claim 1. Fitted from the opening of the upper side of the front Symbol insertion space into the inserting portion, the ladder of claim 1 or claim 2, further comprising a cap member forming the supporting surface together with the inserting portion Combined stepladder. The insertion portion is installed on the outer wall surface in the erection direction in a state where the joint member is mounted on the column, and is horizontally mounted between upper end portions of the pair of columns constituting the ladder body. Has a hole for processing for fixing to the column,
4. The ladder-supporting stepladder according to claim 3 , wherein the cap member has a fitting protrusion that fits into the hole from the inside of the insertion portion in a state of being fitted into the insertion portion. 5. .

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