JP2006193964A - Ladder and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To connect a support and a tread foot stop by an installation at a low cost regarding a mounting and a manufacturing method for the tread foot stop for a ladder. <P>SOLUTION: The ladder has the support 11, to which a stepped hole 23 elongated in the direction crossed with a length is formed, the tread foot stop 12, in which an end section is inserted into the stepped hole 23, and a connecting ring 32 fitted at the end section of the tread horizontal-muntin 12. A radial bulged pushing section 51 pushed to the peripheral surface of the stepped hole 23 through the end section of the tread foot stop 12 is formed to at least a part of the whole periphery of the connecting ring 32. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a ladder and a method for manufacturing the same.

  This type of ladder includes a column with a step hole extending in a direction intersecting the length, a step with an end fitted into the step hole, and the step hole's peripheral surface and the outer surface of the step. A coupling ring interposed therebetween, and a portion of the outer side of the coupling ring in the radial direction is compressed and deformed by a pair of molds on both sides thereof, and the edge of the step hole is There is known one provided with an engaging portion sandwiched from both sides (for example, see Patent Document 1).

The ladder requires a pair of molds to form the engaging portion, and the equipment cost is high. Further, since the engaging portion is formed by deforming only the radially outer portion of the coupling ring, the forming method is not easy, and as a result, there is a problem that the yield is deteriorated.
Japanese Patent Publication No. 48-11427

  An object of the present invention is to provide a ladder that can be coupled to a column and a step with an inexpensive facility and that can be easily manufactured, and a method for manufacturing the same.

  The ladder according to the present invention is inserted into a support column in which a step hole extending in a direction intersecting with the length is formed, a step that has an end inserted into the step hole, and the same end of the step. A coupling ring, and at least a part of the entire circumference of the coupling ring is provided with a radially bulging pressing portion that is pressed against the peripheral surface of the step hole through the same end of the step It is.

  In the ladder according to the present invention, since the strut and the step are combined only by providing a radially bulging pressing portion on at least a part of the entire circumference of the connection ring, the support and the step are combined with an inexpensive facility. In addition, it can be easily manufactured.

  The ladder manufacturing method according to the present invention includes a first step of forming a step hole extending in a direction intersecting with the length in the column, a second step of fitting the end of the step into the step hole, and a step before or after the second step. Later, a third step for fitting the coupling ring into the same end of the stepping step and a deforming part so that at least a part of the entire circumference of the coupling ring bulges outward in the radial direction is provided. And a fourth step of pressing the peripheral surface of the step hole through the same end of the bump.

  In the method of manufacturing a ladder according to the present invention, since the radial bulge-like pressing portion can be provided only by deforming at least a part of the entire circumference of the coupling ring radially outward, the pressing portion can be provided with inexpensive equipment. Can be easily manufactured.

  According to the present invention, it is possible to provide a ladder and a method for manufacturing the same that can be coupled to a column and a step with an inexpensive facility and that can be easily manufactured.

  Embodiments of the present invention will be described below with reference to the drawings.

  1 to 4 show a column 11 on one side of a ladder and one end of a step 12 that forms one step. 1 and 2 show an incomplete product ladder in the middle of manufacture, and FIGS. 3 and 4 show the finished product ladder after manufacture.

  The column 11 has a substantially I-shaped cross section, and includes a central web 21 and flanges 22 at both ends. A step hole 23 is formed in the web 21. The step hole 23 has a substantially triangular shape with rounded corners.

  A short cylindrical bracket 31 having a substantially tapered shape is riveted to the edge of the step hole 23. The tip opening of the bracket 31 has the same shape and concentricity as the step hole 23. One end of the step 12 is fitted from the step hole 23 to the opening of the end of the bracket 31. The tread 12 has a cylindrical shape having an outer surface matched with the peripheral surface of the step hole 23. A coupling ring 32 is fitted in the same end portion of the step 12.

  The support 11, the bracket 31, and the step 12 are made of A6N01SS-T5. The coupling ring 32 is made of A6063SS-T1. The former material is harder and superior in strength than the latter material, and the latter material is more extensible than the former material.

  As shown in detail in FIG. 5, the coupling ring 32 has a cross section substantially similar to the cross section of the tread 12, and is provided with three approximate positions respectively located at three corners of a triangle. It consists of a semicircular arc bent portion 41 and three flat portions 42 that connect adjacent bent portions 41 to each other. In each bent portion 41, a plurality of axial grooves 43 are formed in parallel. The surface between the adjacent grooves 43 of each bent portion 41 is brought into almost local contact with the corner portion of the inner surface of the step 12. The outer surface of the flat part 42 is brought into almost full contact with the flat part 42 on the inner surface of the step 12.

  The ladder is assembled in the state shown in FIGS. 1 and 2, and each bent portion 41 of the coupling ring 32 is deformed so as to bulge outward in the radial direction by an extension jig (not shown). Then, as shown in FIG. 3 and FIG. 4, the groove 43 of each bent portion 41 is mainly deformed so as to be crushed to form a pressing portion 51. Almost all of the bent portions 41 are brought into almost complete contact with the corners on the inner surface of the step 12. At this time, the corner portion of the inner surface of the step 12 is deformed so as to bulge at the same time, and the pressing portion 51 passes through the deformed portion so that the peripheral surface of the step hole 23 and the tip opening edge of the bracket 31 Pressed by the part. As a result, the step 12 is fixed to the column 11.

  This fixing method has the same fixing strength as the welding method. Also, the time for carrying out this method is extremely short compared to welding or the like.

  In the above description, each of the bent portions 41 of the coupling ring 32 is mainly expanded so that the expansion can be easily performed. .

It is a front view of the incomplete ladder by this invention. It is sectional drawing of the unfinished ladder. It is a front view of the completion ladder by this invention. It is sectional drawing of the completion ladder. FIG. 3 is a perspective view of a coupling ring 32 assembled with the unfinished ladder.

Explanation of symbols

11 support
12 Steps
23 Step hole
32 coupling ring
51 Pressing part

Claims (2)

  A strut having a step hole extending in a direction intersecting with the length, a stepper having an end inserted into the step hole, and a coupling ring inserted into the same end of the stepper. And a ladder in which a radially bulging pressing portion pressed against the peripheral surface of the step hole via the same end portion of the step is provided on at least a part of the entire circumference of the coupling ring. A first step for forming a step hole extending in a direction crossing the length of the column; a second step for fitting the end of the step into the step hole; A third step for fitting the coupling ring, and a pressing portion is provided by deforming at least a part of the entire circumference of the coupling ring so as to bulge outward in the radial direction; A method for manufacturing a ladder, comprising a fourth step of pressing the peripheral surface of the hole.

Images