JPH04313435A - Method of manufacturing main frame for shipment container - Google Patents

Abstract

PURPOSE: To dissolve a drawback that many hours are spent for manufacturing a main frame by welding components in a conventional method by forming the main frame as an integral structure, although the main frame capable of housing a refrigerating unit is required for shipping containers used for transporting freights needing temperature control and ventilation. CONSTITUTION: In a manufacturing method of a main frame for shipping containers consisting of a sheet having an integral recessed part, the recessed part is formed by exerting a force in the direction of the main surface of the sheet and by deeply drawing the sheet in the substantially orthogonal direction to it.

Description

[Detailed description of the invention]

0001

FIELD OF THE INVENTION This invention relates to a method of manufacturing main frames for shipping containers.

0002

BACKGROUND OF THE INVENTION Shipping containers are used to transport many different types of cargo. Cargoes requiring temperature control and/or ventilation require refrigeration units that include fan motors, condenser coils, liquid receivers, compressors, contactor panels, and microcomputer controls connected to the shipping container. Traditionally, each shipping container contained a refrigeration unit within the main frame of the container. The main frame was secured to the open end of the refrigeration unit with hack bolts and sealed with silicone.

A typical main frame is shown in FIGS. 1 and 2. The contours of the main frame are made by first stamping and forming sheet metal to the required contours and then welding to form the contours necessary to accommodate the refrigeration unit. However, assembling the main frame in this manner is very time consuming.

0004

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method for manufacturing a one-piece main frame.

[0005]

[Means for Solving the Problems] According to the present invention, in a method of manufacturing a main frame for a shipping container consisting of a sheet having an integral recessed portion, a force is applied in the direction of the main surface of the sheet, and a force is applied to the sheet. A manufacturing method is provided, characterized in that the recessed portion is formed by deep drawing in a substantially perpendicular direction.

The invention will now be described with reference to the illustrated embodiment.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The structural parts of a main frame manufactured in accordance with the present invention are shown in FIG. and sealed with silicone to form an enclosed space. The side part (2) has a concave part (4), a number of contour forming parts (6) and a hole (8).
including.

The first manufacturing step is shown in FIG. Recessed part (
4) is first deep drawn in a direction perpendicular to the plane of the side part (2). If the material used has low ductility in order to prevent cracking, the hydraulic device (10) applies a force on the plane of the side part (2) and the recessed part is deep drawn. Deep drawing is well known to those skilled in the art and typically forms parts from sheet or strip metal with large depth-to-diameter ratios through fairly large plastic strains. The force applied by the hydraulic device (10) causes the material of the side sections to flow uniformly to maintain a specific thickness of the main frame.

FIG. 4 shows the second stage, in which the contour forming part (1
2) is deep drawn in a direction perpendicular to the plane of the side part (2) but opposite to the plane of the recessed part (4), which is deep drawn. The contouring part (6) is also deep drawn at this stage.

In the third manufacturing stage shown in FIG.
is punched out and the excess material (14) is sheared off.

The side part (2) is then fixed to the other side, usually with hack bolts, and sealed with silicone. Preferably the material forming the side part (2) is made from aluminum, but other metals can also be used. The present invention allows the main frame to be made more quickly and efficiently than before, and even if the recessed part (4) is off-center.
The use of a hydraulic device (10) makes it possible to maintain a constant thickness of the side part (2).

Preferably, the deep drawing step is carried out using a 2000 ton hydraulic deep drawing machine. Said machine is well known to those skilled in the art and has at least two pairs of dies. Preferably, the hydraulic device (10) applies a force on the order of 50 tons. The hydraulic device is shown in Figure 6 and consists of two hydraulic cylinders (16) connected to a plate (18) that applies a uniform force on the side part (2).
). The hydraulic cylinder (16) has a hydraulic two-way valve (22
) is driven by a motor (20).

The above-mentioned embodiments are merely illustrative, and as will be apparent to those skilled in the art, the present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the present invention.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing the components of a conventional main frame.

FIG. 2 is a plan view and a cross-sectional view of a conventional assembled main frame.

FIG. 3 is a plan view and a cross-sectional view of the main frame made in the first manufacturing step of the preferred embodiment of the invention;

FIG. 4 is a plan view and a cross-sectional view of the main frame made in the second manufacturing stage of the preferred embodiment of the invention;

FIG. 5 is a plan view and a cross-sectional view of the main frame made in the preferred embodiment.

FIG. 6 is a hydraulic circuit diagram of the hydraulic device used in the preferred embodiment.

[Explanation of symbols]

2 Side part 4 Concave part 6 Contour forming part 8 holes 10 Hydraulic device 12 Contour forming part 16 Hydraulic cylinder 14. Extra materials 20 Motor 22 Hydraulic two-way valve

Claims (6)

[Claims] 1. A method of manufacturing a main frame for a shipping container comprising a sheet having an integral recessed portion, comprising applying force in the direction of the main surface of the sheet and deep drawing in a direction substantially perpendicular to the sheet. A manufacturing method characterized by forming the recessed portion. 2. A resultant force not equal to zero is applied to the sheet to eccentrically form the recessed portion in a major surface of the sheet while the sheet maintains a substantially uniform thickness. The manufacturing method described in. 3. The method according to claim 1, further comprising a deep drawing carried out perpendicularly to the sheet but in a direction opposite to the deep drawing of the recessed portion to produce at least one contouring. manufacturing method. 4. A method according to claim 1, further comprising punching the sheet to form at least one hole. 5. The manufacturing method according to claim 1, further comprising shearing edges of the sheet. 6. A method of manufacturing a main frame for a shipping container substantially as described with respect to any one of FIGS. 3-6.