JP2702011B2 - Manufacturing method of ladder by extruded aluminum - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing an aluminum ladder suitable for use in a truck cabin.

[0002]

2. Description of the Related Art Truck cabins are equipped with ladders so that people can go up and down on a truck roof. Conventionally, this ladder is constructed by assembling an iron pipe material by welding and applying chrome plating to the surface for the purpose of rust prevention and decoration.

[0003]

However, in the conventional iron ladder, there is a problem that rust prevention by chromium plating is insufficient and rust is generated from a welded portion.

Japanese Unexamined Patent Publication No. Sho 62-260985 discloses a ladder of a fire engine using aluminum, but this is mainly for reducing the weight and is used for a truck cabin or the like. And have a different taste.

It is an object of the present invention to provide a method of manufacturing an aluminum ladder having excellent corrosion resistance suitable for mounting on a truck cabin.

[0006]

According to the present invention, there is provided a method for manufacturing a ladder made of aluminum according to the present invention, which comprises connecting a hollow aluminum extruded material having a predetermined length to the inside and outside of the hollow. Forming a frame member by forming a punched hole and bending both end portions of the extruded material, and forming a substantially rectangular frame by joining the bent ends of the pair of frame members to each other; ,
Fixing a step of a predetermined length of aluminum extruded material to the frame by welding.

[0007] Preferably, the hollow extruded material has an irregular cross-sectional shape having an uneven portion, and the uneven portion forms a reinforcing rib along the length direction of the extruded material. In addition, the joining of the frame members is performed by fitting a joint insert into the joint portion of each other and applying an adhesive between the joint insert and the frame member. In addition, a step is provided for fixing the mounting bracket to the frame by welding to facilitate fixing the ladder to the truck cabin. After the welding step and the heat treatment step are completed, the air vent hole is sealed, and finally, the whole is subjected to a glittering treatment by electrolytic polishing and further subjected to an alumite treatment.

[0008]

[Function] By using aluminum, excellent corrosion resistance can be obtained, and by using a hollow extruded material, the structure can be reduced in weight. The air vent holes allow the thermally expanded air in the frame to escape to the outside when the bracket and the step are welded to the frame.

In addition, the irregularities of the irregular cross section become grooves or protrusions in the longitudinal direction of the member, and increase the rigidity of the extruded material, particularly the bending rigidity.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a rear view of a ladder according to an embodiment of the present invention, FIG. 2 is a sectional view taken along line II-II of FIG. 1, and FIG.
II-III sectional view, FIG. 4 is a IV-IV sectional view of FIG.
5 is a perspective view of a frame member of a ladder according to one embodiment of the present invention, FIG. 6 is a front view of a frame assembly of the ladder according to one embodiment of the present invention, and FIG. 7 is one embodiment of the present invention. It is a perspective view of the step of a ladder.

As shown in FIG. 1, the ladder 11 has a substantially rectangular shape having relatively long left and right sides parallel to each other and relatively short upper and lower sides connecting the left and right sides at upper and lower ends thereof. And a plurality of (three in this embodiment) parallel step ridges 13 which are fixed to the left and right sides of the frame 12. Further, an upper bracket 14 and two lower brackets 15 for fixing the ladder 11 to the truck cabin are fixed to the frame 12.

The frame 12 is manufactured by joining two identical frame members 12a together. This frame member 12a is made of a corrosion-resistant aluminum extruded material in the form of a hollow bar, and has both ends bent as shown in FIG. The cross-sectional shape of this extruded material is substantially a rectangular box-shaped cross-section, as is well shown in FIG. 2, for example. Shape. A hollow bar having such a cross-sectional shape is formed by extrusion, cut into a predetermined length, and both ends thereof are bent by a not-shown bender or the like so that the unevenness 12b side is on the inside, and the frame member is formed. 12a is obtained.

Further, as shown in FIG.
An air vent hole 12c communicating the inside of the hollow and the outside is formed in the uneven surface 12b of 2a.

In assembling the frame 12, FIG.
As shown in (2), two identical frame members 12a are joined to each other by fitting the joint insert 16 into their joints. The joint insert 16 has a solid short column shape having a cross section corresponding to the cross section of the frame member 12a so as to be able to just fit into the hollow portion of the frame member 12a. The joint insert 16 is fixed to the frame member 12a by an adhesive 17 applied to the inner peripheral surface of the member 12a,
The frame members 12a on both sides via the joint insert 16
Are fixed to each other.

The step 13 of the ladder 11 is also formed by cutting an extruded material of corrosion resistant aluminum into a predetermined length. As shown in FIG. 7, the step member 13 has a substantially rectangular cross section, and the short side thereof has a concave portion 13a.
have. As shown in FIGS. 1 and 3, the step ridges 13 are arranged so that the pushing direction of the members is horizontal.
2 and fillet weld 18 at both ends
Is fixed to the frame 12.

Further, as shown in FIGS. 1, 2 and 4,
An upper bracket 14 and two lower brackets 15 for attaching the ladder 11 to the truck cabin are fixed to the frame 12 by fillet welds 18. The brackets 14 and 15 have fixing bolt holes 14a and 15a, respectively.
Are drilled.

Here, in these welding steps, the air in the thermally expanded frame 12 escapes from the air vent hole 12c formed in the frame 12 to the outside, so that the pressure in the frame 12 does not become high. As a result, the occurrence of defects in the welded portion is prevented.

After the welding of the frame member 13, the upper bracket 14, and the lower bracket 15 to the frame 12 is completed, a heat treatment (T5 treatment) is performed, and then the above-described air vent hole 12c is sealed with a sealant.

The ladder 11 assembled as described above is thereafter subjected to a glittering treatment by electrolytic polishing and further to an alumite treatment to improve aesthetic appearance and corrosion resistance.

The ladder 11 thus obtained has excellent corrosion resistance and a beautiful surface as compared with a conventional iron ladder.

In this embodiment, the extruded material has an irregular cross section, and has irregularities 12b or recesses 13a. This acts as a reinforcing rib along the extrusion direction of the member, that is, the length direction, and has the effect of increasing the rigidity of the member, particularly the bending rigidity. Also, the irregularities 12b,
The concave portion 13a also has a slip-preventing effect, and prevents slippage of the limbs during lifting and lowering.

[0023]

As described above, according to the present invention, a beautiful aluminum ladder excellent in corrosion resistance and suitable for mounting on a truck cabin can be provided. .

[Brief description of the drawings]

FIG. 1 is a rear view of a ladder according to one embodiment of the present invention.

FIG. 2 is a sectional view taken along line II-II of FIG.

FIG. 3 is a sectional view taken along the line III-III of FIG. 1;

FIG. 4 is a sectional view taken along line IV-IV of FIG.

FIG. 5 is a perspective view of a frame member of a ladder according to one embodiment of the present invention.

FIG. 6 is a front view of a frame assembly of a ladder according to one embodiment of the present invention.

FIG. 7 is a perspective view of a step of a ladder according to an embodiment of the present invention.

[Explanation of symbols]

11 is a ladder according to the present invention, 12 is a frame, 12a is a frame member, 12b is uneven, 12c is an air vent hole,
13 is a step, 13a is a recess, 14 and 15 are brackets, 16 is a joint insert, 17 is an adhesive, and 18 is fillet welding.

Claims (6)

(57) [Claims] A step of forming a frame member by piercing a hollow aluminum extruded material of a predetermined length with air vent holes communicating the inside and the outside of the hollow and bending both end portions of the extruded material; Joining the bent ends of the frame member to each other to form a substantially rectangular frame, and fixing a step of aluminum extruded material having a predetermined length to the frame by welding. A method for manufacturing a ladder by using an extruded aluminum material. 2. The hollow extruded material has an irregular cross-sectional shape having an uneven portion, and the extruded material forms a reinforcing rib along the length direction of the extruded material. Item 4. A method for manufacturing a ladder from an aluminum extruded material according to Item 1. 3. A method of joining a pair of frame members to each other by inserting a joint insert into a joint between the pair of frame members and applying an adhesive between the joint insert and the frame member. A method for manufacturing a ladder using an extruded aluminum material according to claim 1. 4. The method according to claim 1, further comprising a step of fixing a bracket for fixing the ladder to the cabin of the truck by welding to the frame. 5. The method according to claim 1, further comprising a step of sealing the air vent hole after welding and heat treatment. 6. The method for manufacturing a ladder by using an aluminum extruded material according to claim 1, further comprising a step of finally performing a glittering treatment by electrolytic polishing and further performing an alumite treatment.