JP2009030309A - Ladder - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a ladder that can eliminate projection of bolt heads and nuts from posts in the ladder with rungs mounted between the front and rear walls of the posts by bolts which penetrate the front and rear walls of the posts, and nuts screwed to the bolts. <P>SOLUTION: Outside front and rear walls 6, 7 are extended laterally outward from the front and rear end side of sidewalls 5, and inside front and real walls 8, 9 are extended laterally inward from the sidewalls 5 to constitute the right and left posts 2, and the respective right and left end sides of the rung 3 are detachably mounted to the posts 2 by the bolts 17 penetrating the inside front and rear walls 8, 9 of the posts 2, and the nuts 18 screwed to the bolts 17. To prevent the heads 17a of the bolts 17 and the nuts 18 from projecting longitudinally outward from the outside front and rear walls 6, 7, the inside front wall 8 of the post 2 is offset to the longitudinal center side of the post 2 with respect to the outside front wall 6, and the inside rear wall 9 is offset to the longitudinal center side of the post 2 with respect to the outside rear wall 7. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a ladder such as a ladder used for climbing to a high place, a ladder of a stepladder, or a ladder of a work table or a scaffolding platform.

Conventionally, as a ladder provided with a pair of left and right columns and a step bar disposed between the left and right columns and connecting the left and right columns, a ladder in which the step bar is detachable from the column is disclosed in Patent Document 1. Are disclosed.
In the ladder described in Patent Document 1, the column has a horizontal cross-section in the horizontal direction from the side wall whose wall faces in the left-right direction and the front and rear walls extending inward in the left-right direction from the front and rear ends of the side wall. An inwardly open U-shape is formed, and the left and right end portions of the step rail are inserted between the front and rear walls of the column, and the bolts passing through the front and rear walls of the column and the step beam are screwed to the bolts. It is detachably attached to the column with a combined nut, and the step bar can be replaced.
JP 2006-144358 A

As described above, in the conventional ladder, the end portion of the step rail is inserted between the front and rear walls of the column, and the bolt passing through the front and rear wall of the column and the end portion of the step column and the bolt are screwed together. There is a problem in that a step bar is attached to the column by a nut, and a bolt head and a nut for attaching the step beam to the column protrude from an outer surface in the front-rear direction of the column.
SUMMARY OF THE INVENTION In view of the above problems, an object of the present invention is to provide a ladder that prevents the head and nut of a bolt for attaching a tread bar from protruding forward and backward from a column.

The technical means taken by the present invention in order to solve the technical problem is a ladder provided with a pair of left and right struts, and a step bar disposed between the left and right struts to connect the left and right struts.
The left and right struts include a side wall, outer front and rear walls extending outward in the left-right direction from the front and rear end portions of the side wall, and inner side extending from the side wall in the left-right direction. Front and rear walls, and bolts that pass through the front and rear walls inside the column and nuts screwed to the bolts are detachably attached to the left and right ends of the step rail to the column, and the bolt heads and nuts The front wall on the inner side of the column is offset to the center side in the front and rear direction of the column with respect to the outer front wall, and the inner rear wall is moved to the rear It is characterized by being offset to the center side in the front-rear direction of the column with respect to the wall.

Also, with the bolts and nuts removed between the side wall of the column and the left and right end sides of the step beam, the step beam can be It is preferable to provide a gap that can be rotated around.
In addition, there is provided a treadle mounting material fixed to the left and right end sides of the stepping bar, and the treadle mounting material is disposed between the front and rear walls on the inside of the column, and the treadle mounting material and the front and rear sides of the inner side It is good to attach to a support | pillar removably with the volt | bolt which penetrates a wall, and the nut screwed together by this bolt.

The tread bar mounting material includes a mounting wall attached to an end side of the tread bar, and mounting parts provided above and below the mounting wall. It is arranged between the walls, and is fixed to the column by bolts passing through the inner front and rear walls and the mounting portion and nuts screwed to the bolts,
By cutting a shape member having an attachment wall and an attachment part of the tread bar attachment material and having a longitudinal direction in which the bolt penetration direction of the attachment part is a longitudinal direction, the section is cut along a plane perpendicular to the longitudinal direction. It is preferable that the mounting material is formed to have a front-rear width corresponding to the interval between the front and rear walls of the support column.

  According to the present invention, the left and right end sides of the tread bar are detachably attached to the support column by bolts that penetrate the front and rear walls inside the support column and nuts that are screwed to the bolts. The front wall on the inside of the column is offset to the center side in the front-rear direction of the column with respect to the outer front wall so that it does not protrude in the front-rear direction from the outer front and rear walls, and the inner rear wall is relative to the outer rear wall Since it is offset to the center in the front-rear direction of the column, the bolt head and nut can be prevented from protruding outward from the column in the front-rear direction.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
In FIG. 1, reference numeral 1 denotes a single ladder exemplified as a ladder according to the present invention. The ladder 1 includes a pair of left and right columns 2, a step bar 3 that connects the left and right columns 2, and a horizontal direction of the step bar 3. And a tread bar attachment material 4 for attaching the end portion side to the support column 2.
In the following description, “inward in the left-right direction” refers to the direction from the left and right columns 2 toward the center in the left-right direction of the ladder 1, and “outward in the left-right direction” refers to the direction from the center in the left-right direction of the ladder 1 to the left and right columns 2. The inside in the front-rear direction refers to the direction from the end in the front-rear direction of the support column 2 toward the center in the front-rear direction of the support column 2, and the outward in the front-rear direction refers to the end in the front-rear direction from the center in the front-rear direction of the support column 2. The direction.

As shown in FIG. 1, each of the left and right support columns 2 includes a side wall 5 whose wall faces in the left-right direction, and outer front and rear walls 6, 7 extending outward in the left-right direction from the front and rear ends of the side wall 5. And inner front and rear walls 8 and 9 extending inward in the left-right direction from the side wall 5.
Further, the inner front wall 8 is offset from the outer front wall 5 to the center in the front-rear direction (inward in the front-rear direction) of the support 2, and the inner rear wall 9 is supported from the outer rear wall 7. 2 is offset to the center in the front-rear direction (inward in the front-rear direction).
A grounding member 10 is attached to the lower end of the column 2.

A plurality of step bars 3 are arranged in the vertical direction between the left and right support columns 2 and are formed in a cylindrical body (substantially cylindrical body) that is long in the left-right direction and has an axis in the left-right direction. An anti-slip groove is formed on the surface in the longitudinal direction.
As shown in FIG. 1 and FIGS. 3 to 5, the tread bar mounting material 4 includes a mounting wall 11 having a rectangular shape in a side view and a mounting portion provided at the upper and lower ends of the mounting wall 11. 12.
A mounting hole 13 is formed in the center side of the mounting wall 11 in the thickness direction, and the tread bar mounting member 4 is mounted and fixed to the left and right end portions of the tread bar 3 through the mounting hole 13. .

In the present embodiment, the left and right end portions of the step rail 3 are inserted into the mounting hole 13 and a pair of left and right formed so as to protrude radially outward by bulging the step rail 3. The mounting wall 11 is fixedly attached to the end portion side of the tread bar 3 by sandwiching the mounting wall 11 from the left and right sides by the convex portion 14.
In addition, in order to restrict the relative rotation of the step bar 3 and the step bar mounting member 4 about the left and right axis, an arcuate recess 15 is formed at the edge of the mounting hole 13, and the wall surface of the mounting wall 11 is formed. The ridges 16 are formed in the front-rear direction.

The upper and lower mounting portions 12 are provided in the front-rear direction of the mounting wall 11, and the upper mounting portion 12 is formed in a substantially cylindrical shape having an axial center in the front-rear direction and lacking a part on the upper surface side in the front-rear direction. The lower mounting wall 12 is formed in a substantially cylindrical shape having an axial center in the front-rear direction and a portion of the lower surface side missing in the front-rear direction. Bolts 17 are inserted through the upper and lower mounting parts 12 in the front-rear direction (through). ) It is possible.
Further, the end of the step bar 3 in the left-right direction is such that the end of the step bar 3 does not protrude outwardly from the upper and lower mounting parts 12 of the step bar mounting member 4 in the left-right direction. It is fixed to.

The tread bar mounting material 4 is formed to have a front-rear width W corresponding to the distance between the front wall 8 and the rear wall 9 inside the support column 2, and the left and right tread bar mounting materials 4 are the same in the left-right direction. For example, a bolt 17 that is disposed between the front and rear walls 8 and 9 of the support column 2 on the side, passes through the inner front wall 8, passes through the attachment portion 12, and passes through the inner rear wall 9, and the bolt 17 It is detachably attached to the support column 2 by a nut 18 screwed into the front end side from behind.
In the ladder 1 configured as described above, the head 17a of the bolt 17 for mounting the tread bar mounting material 4, the tip 17b of the bolt 17 and the nut 18 are in the front-rear direction relative to the outer front and rear walls 6 and 7. The front and rear walls 8 and 9 on the inner side of the column 2 are offset to the center side in the front and rear direction of the column 2 with respect to the outer front and rear walls 6 and 7 so as not to protrude outward (bolt head 17a, bolt tip portion) 17b and the nut 18 are formed so as not to protrude from the front and rear outer end surfaces of the support column 2).

  Further, as shown in FIG. 6, in the present embodiment, the tread bar mounting material 4 is formed in the same cross-sectional shape as the cross section obtained by cutting the tread bar mounting material 4 along a plane orthogonal to the front-rear direction. Profile 19 such as a long aluminum (extruded or drawn shape such as a long aluminum having the mounting wall 11 and the upper and lower mounting portions 12 and having the axial direction of the upper and lower mounting portions 12 as the longitudinal direction) Is formed by extrusion molding or pultrusion molding, and the shape member 19 has a predetermined width W (a width corresponding to the interval between the front and rear walls 8 and 9 inside the support column 2) on a surface orthogonal to the longitudinal direction of the shape member 19. And is formed by drilling the mounting hole 13.

Further, the tread bar mounting material 4 is fixedly attached to the front and rear walls 8 and 9 inside the support column 2 while being separated from the side wall 5 of the support column 2 in the left-right direction, and the bolt 17 and nut 18 are removed. In order to allow the tread bar 3 to be removed in the front-rear direction from between the columns 2, there is a gap between the tread bar mounting material 4 and the side wall 5 of the column 2 so that the tread bar 3 can be rotated about the front and rear axis. S is provided.
For example, as in the case of a conventional ladder, the left and right end portions of the step rail are arranged between the front and rear walls of the column, and the left and right ends of the step frame are in contact with the side wall of the column. Even if you remove the bolts and nuts for attaching the treadle, there are front and rear walls of the column on the front and rear sides of the side of the treadle, so remove the treadle between the left and right columns in the front and rear direction It is not possible.

Therefore, when removing the treadle on a conventional ladder, the bolts and nuts for attaching the treadle are removed, the space between the columns is widened, and the treadle is rotated around the front and rear axes, thereby The left and right ends of the column are positioned so that they do not overlap with the front and rear walls of the column, and the column is removed from between the left and right columns by moving the column back and forth in this state. There is a problem that it is difficult to replace the crosspiece.
On the other hand, in the ladder 1 according to the present embodiment, a gap S is provided between the tread bar mounting member 4 and the side wall 5 of the column 2 so that the tread bar 3 can be rotated around the front and rear axes. Therefore, by removing the bolts 17 and nuts 18 fixing the stepping bar mounting material 4, the stepping bar mounting material 4 can be rotated even if the stepping bar 3 is rotated about the front-rear axis as shown in FIG. 7. (And the left and right ends of the tread bar 3) are in contact with the side wall 5 of the column 2 so that the rotation of the tread bar 3 is not restricted, and the tread bar 3 is rotated about the longitudinal axis. Thus, the footrest mounting material 4 (and the left and right ends of the footrest 3) can be positioned at a position that does not overlap the front and rear walls 8 and 9 inside the column 2 with respect to the front and rear direction. Remove the crosspiece 3 in the front-rear direction from between the left and right struts 2 by moving the front-rear 3 Can be, it is possible to easily exchange the tread crosspiece 3 thereby.

In order to attach the step bar 3 to the column 2, without using the step frame mounting material 4, the left and right ends of the step frame 3 are directly inserted between the front and rear walls 8 and 9 inside the column 2, The step bar 3 may be attached to the column 2 by bolts passing through the front and rear walls 8 and 9 and the end of the step bar 3 and nuts screwed to the bolts. Is attached so that the end of the step bar 3 is separated from the side wall 5 of the column 2 inward in the left-right direction, and between the end of the step bar 3 and the side wall 5 of the column 2 A gap is provided so that the crosspiece 3 can be rotated around the longitudinal axis.
Further, in the present embodiment, the tread bar mounting material 4 is formed by cutting the long shape member 19 into a predetermined width W along a plane orthogonal to the longitudinal direction of the shape member 19 to thereby change Since it is formed in the front-rear width W corresponding to between the walls 8, 9, it is possible to easily cope with the pillars 2 of various sizes having different intervals between the front-rear walls 8, 9 inside the pillar 2.

In addition, in the conventional ladder, the end portion of the step rail is inserted between the front and rear walls of the column, and a bolt that passes through the front and rear walls of the column and the end portion of the column and a nut that is screwed to the bolt. Since the step rail is attached to the column, the front and rear width of the step beam must be formed to a width corresponding to the width between the front wall and the rear wall of the column. There is a problem that the material cost becomes high due to the wide width.
On the other hand, in the present embodiment, in order to removably join the tread bar 3 to the column 2, the tread bar mounting material 4 attached and fixed to the left and right ends of the step bar 3 is attached to the inside of the column 2. It is arranged between the front and rear walls 8 and 9, and the stepping bar mounting member 4 is attached to the column 2 by a bolt 17 passing through the stepping bar mounting member 4 and the inner front and rear walls 8 and 9 and a nut 18 screwed into the bolt 17. Since it is attached detachably, it is not necessary to form the front-rear width of the tread bar 3 to a width corresponding to the distance between the front and rear walls 8, 9 of the support column 2, and is suitable for ascending and descending the ladder 1. A treadle can be formed.

Further, in the case of attaching a part to the outer surface of the support column 2 in the front-rear direction, by attaching the component to the outer surface of the inner front and rear walls 8, 9, the amount of protrusion of the component in the front-rear direction can be reduced. (Or it can be prevented from protruding).
8 to 13 show a dual ladder 1 exemplified as another ladder 1 employing the present invention. The ladder 1 is movable in the longitudinal direction (movable up and down) with respect to the lower ladder 1A and the lower ladder 1A. An upper ladder 1B engaged with the upper ladder 1B, an operation rope 20 for raising and lowering the upper ladder 1B, a pair of upper and lower pulleys 21 and 22 around which the operation rope 20 is wound, and a lowering of the upper ladder 1B relative to the lower ladder 1A ( And a lock device 23 that restricts movement in the contraction direction.

In the state where the upper ladder 1B is positioned at the contracted position which is the lower limit position of the vertical movement range (contracted state), the extension direction of the upper ladder 1B relative to the lower ladder 1A (the same as the upward direction of the upper ladder 1B relative to the lower ladder 1A) It is preferable to provide an extension stop device that restricts movement in the direction).
The lower ladder 1A and the upper ladder 1B have the same configuration as the ladder 1 shown in FIGS. 1 to 7, and the same members are denoted by the same reference numerals and the description thereof is omitted.
The grounding member 10 is provided on the lower end side of the lower ladder 1A, the upper ladder 1B is disposed on the back side of the lower ladder 1A, and the upper ladder 1B overlaps the lower ladder 1A in the front-rear direction at the contracted position.

Engagement brackets 24L and 24R (referred to as upper engagement brackets) that engage with the upper ladder 1B are provided on both the left and right sides of the upper ladder 1A, and the lower ladders are provided on the left and right sides of the lower ladder 1B. Engagement brackets 25L and 25R (hereinafter referred to as lower engagement brackets) that engage with 1A are provided, and the upper ladder 1B moves up and down with respect to the lower ladder 1A via the upper and lower engagement brackets 24 and 25. The upper ladder 1B is engaged with the lower ladder 1A so as to be movable and to restrict the movement of the upper ladder 1B in the left-right direction and the front-rear direction relative to the lower ladder 1A.
The upper engagement brackets 24L and 24R are superposed on the outer surface of the side wall 5 of the column 2 of the lower ladder 1A and are bolted to the side wall 5, and the front wall 6 outside the column 2 of the upper ladder 1B. The engagement member 27 engages so as to be vertically movable with respect to the inner side and the front and rear in the left-right direction, and a holding portion 28 that holds the engagement member 27 fixedly. ing.

The engaging member 27 may be integrally formed with the holding portion 28.
Further, a pulley bracket 29 located on the outer side in the left-right direction of the side wall 5 of the column 2 of the upper ladder 1B is provided on the rear end side of the holding portion 28 on the upper engagement bracket 24R on the left and right sides (right side in the present embodiment). The upper pulley 21 is supported by the pulley bracket 29 so as to be rotatable about the left-right axis. The lower engagement brackets 25L and 25R are located on the same side in the left-right direction. The engaging brackets 24L and 24R are configured in the same manner, and the mounting portions 26 of the lower engaging brackets 25L and 25R are overlapped with the outer surface of the side wall 5 of the column 2 of the upper ladder 1B and fixed to the side wall 5 with bolts. The engaging members 27 of the lower engaging brackets 25L and 25R are engaged with the rear wall 7 outside the support 2 of the lower ladder 1A, and the pulley bracket 29 integrally formed with the lower engaging bracket 25R on the right side is the lower ladder. 1 The side pulley 5 is positioned on the outer side in the left-right direction of the side wall 5 of the column A, and the lower pulley 22 is supported by the pulley bracket 29 so as to be rotatable around the axis in the left-right direction.

One end of the operation rope 20 is fixed to the upper end of the support 2 of the lower ladder 1A. The operation rope 20 is disposed downward from the operation rope 20 and wound around the lower pulley 22 and then disposed upward. It is installed and wound around the upper pulley 21, and thereafter, the other end side is disposed downward so as to reach the lower end side of the upper ladder 1B. The other end side of the operation rope 20 and the upper pulley The upper ladder 1B is lifted by grasping the space between the two and pulling it downward.
The lock device 23 is pivotally supported by a fastener mounting seat 31 that is fixedly attached to the inner side surface of the side wall 5 of the column 2 of the upper ladder 1B, and the lower end of the stopper mounting seat 31 is rotatable about the left-right axis. A stopper 32 that is swingable back and forth and a button claw 33 pivotally supported by the stopper 32 are provided.

When the upper ladder 1B is raised, the stopper 32 comes into contact with the step 3 of the lower ladder 1A to escape backward to allow the upper ladder 1B to rise. When the upper ladder 1B is lowered with the pawls 33 positioned above the rail 3 and the lower claw 33 positioned below the step ladder 3 of the lower ladder 1A, the stopper 32 is engaged with the step ladder 3 of the lower ladder 1A from above. In combination, the lowering of the upper ladder 1B is restricted.
Further, when the upper ladder 1B is lifted, the button claw 33 comes into contact with the step bar 3 of the lower ladder 1A from the lower side to escape backward to allow the upper ladder 1B to be lifted. When the upper ladder 1B is lowered while the upper ladder 1B is positioned above the stepping bar 3 of the lower ladder 1A, the buttoning claw 33 contacts the stepping bar 3 of the lower ladder 1A from above, so that the buttoning claw 33 is fixed to the stopper 32. And the upper ladder 1B descends.

The locking device 23 is provided with a return spring that urges the stopper 32 to return to a position where it can be engaged with the step bar 3 of the lower ladder 1A.
In addition, the present invention, as in the above-described embodiment, is employed in a single or double ladder, a triple ladder, a ladder of a stepladder formed by connecting the top ends of a pair of ladders with a top plate, You may employ | adopt for ladders, such as a scaffolding platform or a work platform which connects the upper end side of a pair of ladders with a scaffold board or a step board, etc., and the ladder 1 which connected the left-right paired support | pillar 2 with the at least 1 step crosspiece 3 Can be adopted.

It is plane sectional drawing of the connection part of a support | pillar and a treadle. (A) is a front view of a ladder, (b) is a left side view of the ladder. It is a front fragmentary sectional view which shows the connection structure of the treadle with respect to a support | pillar. FIG. 4 is a sectional view taken along line AA in FIG. (A) is a side view of a tread bar mounting material, (b) is a front view of the tread bar mounting material. It is a side view of an extrusion shape member. It is the front view which showed the state which rotates a tread about a front-back axis. The double ladder which employ | adopted this invention is shown, (a) is a front view of a ladder, (b) is a left view of a ladder. It is a front enlarged view of a double ladder. It is a left side enlarged view of a double ladder. It is a right side enlarged view of a double ladder. FIG. 9 is a cross-sectional view taken along line B-B in FIG. It is CC sectional view taken on the line of FIG.

Explanation of symbols

2 strut 3 step bar 4 step bar mounting material 5 side wall 6 outer front wall 7 outer rear wall 8 inner front wall 9 inner rear wall 11 mounting wall 12 mounting portion 17 bolt 17a bolt head 18 nut 19 profile S Left and right ends of the tread bar and gap between the tread bar mounting material and the side wall of the column W W front and rear width of the tread bar mounting material

Claims (4)

In a ladder provided with a pair of left and right struts and a step bar that is arranged between the left and right struts and connects the left and right struts,
The left and right struts include a side wall, outer front and rear walls extending outward in the left-right direction from the front and rear end portions of the side wall, and inner side extending from the side wall in the left-right direction. Front and rear walls, and bolts that pass through the front and rear walls inside the column and nuts screwed to the bolts are detachably attached to the left and right ends of the step rail to the column, and the bolt heads and nuts The front wall on the inner side of the column is offset to the center side in the front and rear direction of the column with respect to the outer front wall, and the inner rear wall is moved to the rear A ladder characterized by being offset to the center side in the front-rear direction of the column with respect to the wall.   With the bolts and nuts removed, between the side wall of the column and the left and right ends of the step frame, the step frame can be rotated around the front and rear axis so that the step frame can be removed from the left and right columns to the front and rear side. The ladder according to claim 1, wherein a gap that can be rotated is provided.   A treadle mounting material fixed to the left and right end sides of the stepping bar is provided, and the treadle mounting material is disposed between the front and rear walls on the inner side of the column, and the stepping bar mounting material and the inner front and rear walls are disposed. The ladder according to claim 1 or 2, wherein the ladder is detachably attached to the support column by a penetrating bolt and a nut screwed to the bolt. The tread bar mounting material includes a mounting wall attached to the end side of the tread bar and mounting parts provided above and below the mounting wall, and the upper and lower mounting parts are provided between the front and rear walls inside the column. Is mounted and fixed to the column by a bolt penetrating the inner front and rear walls and the mounting portion and a nut screwed to the bolt,
By cutting a shape member having an attachment wall and an attachment part of the tread bar attachment material and having a longitudinal direction in which the bolt penetration direction of the attachment part is a longitudinal direction, the section is cut along a plane perpendicular to the longitudinal direction. The ladder according to claim 3, wherein the attachment member is formed to have a front-rear width corresponding to a space between front and rear walls of the support column.

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