JPH0374314B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention protrudes a small number of protrusions at a predetermined distance from the top and bottom of a strip-shaped steel plate, and
After covering and sandwiching the interior material for the door, which has been bent into a letter shape, a "dog" shape, or any other suitable form to make it self-supporting, between the upper and lower steel plates, the protrusion pieces are turned off by applying electricity from the protrusion piece to the steel plate. The present invention relates to a door manufacturing method that allows the door to be manufactured in a flat shape without causing cracks, irregularities, etc. due to melting, and moreover, more easily than in the past.

[Conventional technology]

As shown in Figure 6, for example, as a means of manufacturing doors made of steel plates, which have been widely used in the past,
(i) An interior material 3 with a horizontal U-shaped cross section is interposed inside the upper and lower (or front and back, hereinafter referred to as upper and lower for convenience of explanation) steel plates 1 and 2, and the end of the horizontal part _h2 is attached to the steel plate 2. Welding is performed, and then a hole is made using a punching machine (not shown) across the horizontal portion _h1 and the steel plate 1, and this hole is filled with welding material and welded to form the three parts, the steel plates 1 and 2 and the interior material 3, into one piece. (ii) Then, the "burrs" i ₁ and i ₂ that protrude to the outside of the steel plates 1 and 2 by welding are removed using a sander (not shown), and (iii) the above-mentioned burrs are removed using putty (not shown). After correcting the unevenness at the excised portion and making it flat, the outer surfaces of the steel plates 1 and 2 are painted to produce a usable door 4.

[Problem to be solved by the invention]

In the production method using the conventional technology mentioned above, traces of the parts removed by the sander remain, and even though a putty finish is applied, the presence of uneven parts cannot be avoided. It is extremely difficult to do so. As shown in FIG. 7, one way to improve this problem is to install horizontal parts h ₃ and h 4 of the interior material 7, which has a horizontal U-shaped cross section, on the inside of the upper and lower steel plates 5 and ₆ . By bringing small protrusions e ₁ and e ₂ into contact and applying current to the welding materials 8 and 9 set at the top and bottom, respectively, spot welding is performed and the burrs i ₃ and i ₄ generated by welding are removed. In this case, the protrusion pieces e 1 and e 2 are twisted in the vicinity of the protrusion pieces e ₁ and e ₂ due to the local electricity supply to the protrusion pieces e ₁ and e ₂ . There is a high possibility that cracks or unevenness will occur, and the protrusions e ₁ and e ₂ will cave in due to excessive energization, causing the steel plates 5 and 6 to collapse.
are curved convexly toward the interior material 7, and therefore,
It becomes virtually impossible to make corrections in the vicinity of protrusions e ₁ and e ₂ , which not only wastes time and effort, but also leads to the disposal of the material itself, which has the disadvantage of being uneconomical. ing.

This invention was proposed in view of the above-mentioned drawbacks, and its purpose is to make it possible to manufacture flat, uniform, and high-quality doors without creating cracks or unevenness on the upper and lower surfaces, and It is an object of the present invention to provide a door manufacturing method that can reduce the labor and time required during manufacturing compared to conventional methods.

[Means to solve the problem]

In order to achieve the above-mentioned object, the door manufacturing method according to the present invention includes a process in which an appropriate number of through holes are formed near the inner side of the upper and lower edges along the longitudinal direction of an interior material made of a belt-shaped bendable steel plate, and the holes are bulged outward. Each of the protruding pieces is brought into contact with the inner wall surface of a pair of opposing steel plates, and after the pressing body is brought into close contact with the outside of each of these steel plates, an electrode is brought into contact with each of the protruding pieces, and an electrode is brought into contact with each of the steel plates, The protruding piece and the pair of steel plates are integrally joined by melting the protruding piece by applying electricity from the protruding piece to the pair of steel plates.

〔Example〕

The embodiment of the present invention will be described below with reference to FIGS. 1 to 5. A steel plate S is formed into a band shape and bent into a wave shape so that it can stand on its own. A piece of interior material 21 is produced by protruding and forming a protrusion piece a with a mountain-shaped cross section (normally 1.0 mm or more is preferable, but an appropriate value may be adopted as needed). As shown in FIG. 1, this interior material 21 is arranged and interposed between the upper and lower rectangular steel plates 22 and 23 in an appropriate number of rows (four rows in this case) along the longitudinal direction thereof. . By bringing the pressing bodies 24 and 25 into close contact with the upper and lower surfaces of the steel plates 22 and 23, respectively, the occurrence of unexpected situations such as deformation and rocking during welding of the interior material 21 to the steel plates 22 and 23 can be prevented in advance. It is desirable to do so.

In addition, when forming the projection pieces a, as shown in FIG. 5, an appropriate number (here, two pieces) are punched (not shown) at predetermined intervals near the inner side of the upper and lower edges of the steel plate S. By drilling the through hole q, the edge swells slightly outward to form the protruding piece a, and as described later, the protruding piece a melts and disappears, and the upper and lower parts of the interior material 21 By flattening each edge, the momentary shock or vibration generated when the interior material 21 is joined to the steel plates 22 and 23 sandwiched above and below is alleviated and absorbed by the through hole q, and the protruding piece a The interior material 21 and the steel plates 22, 23 can be integrally joined together smoothly and quickly based on the melting and disappearance of the material, and the occurrence of deformation, twisting, etc. in the vicinity of the projection piece a can be effectively prevented.

[Effect]

The interior material 21 is parallel and sandwiched between the upper and lower rectangular steel plates 22 and 23 along the longitudinal direction, as shown in FIG.
After the pressing bodies 24 and 25 are brought into close contact with the upper and lower surfaces of each at the position _P1 , the electrodes of the protruding piece a are brought into contact with the electrodes of the steel plates 22 and 23, respectively, and energized (energized by alternating current). ), and spot welding is performed until the projection piece a melts and disappears (albeit momentarily). Then, by this energization, only the protruding piece a melts momentarily, and the interior material 21 and the steel plate 22,
23 are integrally joined. Then the pressing body 24,
When the interior material 21 and the steel plates 22 and 23 are integrally joined at the position P ₂ of the door 25 in the same manner as described above, one usable door D can be manufactured. It should be noted that when copper powder or a mixture of copper powder and silver powder is applied to the protruding piece a prior to welding, the current flow can be further improved and the welding can be performed more satisfactorily.

〔effect〕

According to this invention, since there are many small welded spots throughout the door, there are very few scars caused by the heat generated during welding, and no visible irregularities remain, allowing the steel plate to remain flat. Furthermore, since the interior material and the steel plate are welded instantaneously and at multiple locations at the same time, the time and effort required for processing is much greater than conventional welding, sancer finishing, and putty finishing. The width is reduced, and
Traditionally, steel plates were arc welded,
Normally, a thickness of at least 1.6 mm is required, but in this invention, the interior material and the steel plate can be interconnected by spot welding, so the thickness of the steel plate can be reduced to 1/2 of the conventional thickness. In other words, approximately 0.8 mm is sufficient, which not only saves materials, but also greatly reduces the weight of the entire door compared to conventional doors. The part of the protrusion that melts due to energization is offset by the deformation of the through hole itself drilled near the inside of the protrusion, and the melting of the protrusion also reduces the impact and vibration caused by the momentary contact between the interior material and the steel material. The entire surface of the steel plate can be formed into a flat shape, and a pressing body is placed in close contact with the outside of each steel plate, so that unexpected situations such as deformation and shaking can occur when the interior material and the steel plate come into contact. In addition, it is possible to prevent this from occurring in advance, and because the interior material, which has a horizontal U-shaped cross section, is joined to the steel plate, it is possible to avoid conventional manufacturing methods, which inevitably result in visible twists, cracks, or irregularities during welding. In comparison, the interior material is shaped like a band and has small protrusions at predetermined intervals, and is interposed between the steel plates. Furthermore, since the protrusions of this interior material are used to supply electricity to each of the pair of opposing steel plates, the melting time is shorter than that of the conventional material. It is possible to shorten the welding time compared to the conventional welding process, and it is possible to perform uniform welding at all times.It is also possible to distribute external force evenly, greatly reducing the risk of twisting or cracking, and it is also possible to manufacture the interior material itself. It's extremely simple, and since it's bent at the right places, it can be stacked, so you don't need unnecessary space when storing and arranging it, and you can easily connect the electrodes by checking where the through holes are set. This prevents the worker from misidentifying the contact member of the electrode, and allows the welding work to be performed quickly and safely.

In addition, welding does not require any skill, experience, or sensitivity on the part of workers, and any number of people can weld it very easily.Furthermore, uniform doors can be manufactured without the use of tools such as sanders or putty, making it possible to produce large quantities of doors. It is inexpensive, and has higher precision than conventional methods.
It also has the characteristics of being able to supply the market with doors with great strength.

Incidentally, if an appropriate number of desired through holes are formed in the interior material 21, the weight of the door can be further reduced.

[Brief explanation of drawings]

Fig. 1 is a plan view of a door to which the interior material of the present invention is attached, Fig. 2 is an enlarged sectional view of the main part taken along the - line in Fig. 1, and Fig. 3 is a fabrication of an embodiment taken along the - line in Fig. 1. Figure 4 is an enlarged sectional view of the main parts of the process, Figure 4 is a plan view of the main parts of the interior material, Figure 5 is an enlarged view of the vicinity of the protruding piece, Figures 6 a, b, and c are explanatory diagrams of the conventional door manufacturing process.
FIGS. 7a and 7b are explanatory diagrams of other conventional door manufacturing steps. 21... Interior material, 22, 23... Steel plate, 24,
25...Press body, D...Door, a...Protrusion piece, q...
...through hole.

Claims (1)

[Claims] 1. A suitable number of through holes are drilled near the inside of the upper and lower edges along the longitudinal direction of the interior material made of a belt-shaped bendable steel plate, and protrusions that bulge outward are attached to the inner wall surfaces of a pair of opposing steel plates. After bringing the pressing body into close contact with the outside of each of these steel plates, an electrode is brought into contact with each of the protruding pieces, and an electrode is brought into contact with each of the steel plates, and the protruding pieces are melted by applying current from the protruding pieces to the pair of steel plates. A door manufacturing method in which the protruding piece and a pair of steel plates are integrally joined.