Half-complete flat body and method for manufacturing the same

Abstract

To provide a half-complete flat body expected to be greatly improved in deliver by ensuring rusting difficulty and durability even while it is made of iron and forming a ladder frame which serves as a ladder-shaped base which requires a most important technique.SOLUTION: A half-complete flat body P formed separately from a truck 9 and attached on a frame 92 of the truck comprises: an iron ladder frame RF formed by setting a plurality of horizontal sills 3 across at least two separated vertical sills 2 to weld and join them in a ladder shape and welding and joining a side rocker 4 to the end surface of the horizontal sills 3 protruding outside the vertical sills 2; and a molten galvanized layer 1 in which the entire outer peripheral surface of the ladder frame is covered to be integrated.SELECTED DRAWING: Figure 9

Description

[Technical field]

[0001] The present invention relates to a semi-finished flat body, which is the most important and technically demanding part in manufacturing a flatbed truck bed, and a manufacturing method thereof. [Background technology]

[0002] Truck manufacturers basically manufacture in their own factories only the frame 92 shown in Figure 11, which does not have the loading platform, and this state of the truck 9 becomes the finished product after it comes off the production line. The loading platform has a variety of shapes to suit the various loads, such as solids, liquids, gases, and the various sub-loads that can be subdivided from those, and they are manufactured in a variety of places, from specialized manufacturers to local body factories. Finally, local body factories, which receive requests from each dealer, carry out secondary bodywork, including painting, to a greater or lesser extent, and the vehicle is then newly registered at the Land Transport Bureau and delivered. The two most common body shapes are the wing type and the flat type. Here, only medium-sized flatbed cars are available as finished vehicles, and flatbed cars larger than medium-sized cars are mostly made by hand at local body factories that receive orders from dealers, which is called "made body". However, the labor shortage is serious in every industry these days, and the shortage of craftsmen is particularly noticeable. Furthermore, not only is the number of local body factories that were responsible for the production of large flatbed cars decreasing, but because there were only a limited number of craftsmen who could assemble made bodies, the situation is becoming even more severe in terms of both delivery time and quality.

[0003] In addition, conventionally, vertical joists made of wood or iron are placed on two frames 92 extending from the front and rear of the truck, and horizontal joists made of wood or iron are crossed and attached to these. However, in terms of quality, wood has the disadvantage of being prone to corrosion, and iron has the disadvantage of being prone to rust. In this context, a joist structure has been proposed that overcomes the shortcomings of wood and steel structures (for example, Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Utility Model Registration No. 3079112 Summary of the Invention [Problem to be solved by the invention]

[0005] However, Patent Document 1 only proposes "a joist structure in a truck bed, characterized in that both or one of the vertical and horizontal joists are made of FRP," as stated in claim 1. It is true that FRP does not corrode, is light, and has mechanical strength comparable to that of metal materials, but it has a heat resistance of about 100 to 140 degrees Celsius, which means that it not only burns when exposed to high heat, but also cracks when subjected to impact. In addition, there are rare cases of bodies made entirely of aluminum, which are light, resistant to corrosion and rust, but the material cost is more expensive than iron, and because the material is weak, the number of joists must be increased to ensure the strength of the body. This limits the contribution to weight reduction and increases the manufacturing process, resulting in an overall expensive loading platform, and in terms of corrosion and rust prevention measures alone, it cannot be said to be cost-effective.

[0006] The present invention aims to solve the above problems by providing a semi-finished flat body and a manufacturing method thereof which is made of iron but is rust-resistant and durable, and which can be expected to dramatically improve delivery times by fabricating the ladder frame, which serves as the ladder-shaped base, which is the most important and requires the most skill. DISCLOSURE OF THEINVENTION [Means for solving the problem]

[0007] In order to achieve the above object, the first aspect of the present invention is a semi-finished flat body that is formed separately from a truck and is attached to the frame of the truck, and is characterized by comprising an iron ladder frame in which at least two separated vertical joists are crossed and welded in a ladder shape, and side rockers are welded to the end faces of the horizontal joists that protrude outward on both sides from the vertical joists, and a hot-dip galvanized layer that coats and integrates the entire outer periphery of the ladder frame.The semi-finished flat body of the second aspect of the present invention is characterized in that, in the first aspect, a plurality of floor hooks, a plurality of center stanchion pockets, and a plurality of side stanchion pockets are welded to the ladder frame, and the hot-dip galvanized layer is also integrally coated on the outer periphery of all of these. In addition, a third aspect of the present invention is a manufacturing method for a semi-finished flat body that is formed separately from a truck and attached to the frame of the truck, characterized in that a plurality of horizontal joists are crossed and welded to at least two spaced apart vertical joists in a ladder shape, and side rockers are welded to the end faces of the horizontal joists that protrude outward on both sides beyond the vertical joists to form an iron ladder frame, and then the ladder frame is immersed in a hot-dip galvanizing tank and cooled to form a hot-dip galvanized coating that is integrated onto the entire outer peripheral surface of the ladder frame. The manufacturing method for a semi-finished flat body of the fourth aspect of the present invention is characterized in that, in the above-mentioned third aspect, a plurality of floor hooks, a plurality of center stanchion pockets, and a plurality of side stanchion pockets are welded to the ladder frame, the ladder frame to which these are joined is immersed in a molten zinc plating tank and then cooled to form an integrated molten zinc plating coating on the entire outer peripheral surfaces of the ladder frame as well as the entire outer peripheral surfaces of the floor hooks, the center stanchion pockets, and the side stanchion pockets.

[0008] (action) The present invention, which comprises an iron ladder frame and a hot-dip galvanized layer integrally coating the entire outer periphery of the frame, is more effective in preventing rust on the iron ladder frame than electrolytic galvanization due to the physical rust prevention effect of the thick galvanized layer and the chemical rust prevention effect of the sacrificial corrosion prevention effect, and is effective in improving durability, weather resistance, etc. Moreover, unlike electrolytic galvanization, hot-dip galvanization forms an alloy layer between the iron and zinc, which provides high adhesion between the two and results in a semi-finished flat body with a galvanized layer that is resistant to impacts. Furthermore, when the ladder frame is made into a semi-finished flat body with the entire outer surface coated with a hot-dip galvanized layer, the ladder frame is a flat body in which the technically difficult parts have already been assembled, so it does not take much time to complete the flat body, which has the advantages of shortening delivery times, standardizing quality, and optimizing equipment. If a semi-finished flat body is made in which multiple floor hooks, multiple center stanchion pockets, and multiple side stanchion pockets are welded to the ladder frame, and all of the outer peripheral surfaces are integrally coated with the hot-dip galvanized layer, floor hooks and the like will be added as standard equipment, which will further improve quality uniformity and also help shorten delivery times. Effect of the Invention

[0009] The semi-finished flat body and its manufacturing method of the present invention is a semi-finished body comprising a ladder frame, which is the most important and technically demanding ladder-shaped base part, and a hot-dip galvanized layer integrally covering the entire outer periphery of the ladder frame, and by using this, the manufacturing period of the body can be shortened and the quality can be made uniform regardless of the skill of the craftsman. Furthermore, the hot-dip galvanized layer integrally covering the entire outer periphery of the ladder frame provides a great advantage in that it is possible to provide a semi-finished mass-produced body that is completely rust-proofed. [Brief description of the drawings]

[0010] [Figure 1] FIG. 2 is a perspective view of a semi-finished flat body without a hot-dip galvanized layer, as seen from the front of the vehicle. [Diagram 2] FIG. 2 is an enlarged rear perspective view of FIG. [Diagram 3] FIG. 2 is a plan view of FIG. [Figure 4] FIG. 4 is an enlarged view of the upper part of FIG. 3 on the front side of the vehicle. [Diagram 5] FIG. 4 is an enlarged view of the lower part of FIG. 3 on the rear side of the vehicle. [Figure 6] 6 is a view taken along line VI-VI in FIG. 4. [Figure 7] This is an enlarged view in which the enlarged view within the circle in Figure 6 has been replaced with a semi-finished flat body. [Figure 8] 8 is a view taken along line VIII-VIII in FIG. 5 and is an enlarged view of a semi-finished flat body provided with a hot-dip galvanized layer. [Figure 9] This is an oblique view of the semi-finished flatbed body seen from the rear side of the vehicle. [Figure 10] FIG. 2 is a perspective view of a finished truck after it has been rolled off the production line at a truck manufacturer. [Figure 11] FIG. 11 is a schematic side view of the completed truck of FIG. [Figure 12] FIG. 11 is a schematic side view of the semi-finished flat body attached. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] The semi-finished flat body and the manufacturing method thereof according to the present invention will be described in detail below. Figures 1 to 12 show one embodiment of the semi-finished flat body (hereinafter also referred to as "semi-finished flat body") of the present invention and its manufacturing method, in which Figure 1 is an oblique view of a semi-finished flat body without a hot-dip galvanized layer (hereinafter also referred to as "semi-finished flat body before hot-dip galvanized treatment"), Figure 2 is an enlarged view of the rear of Figure 1, Figure 3 is a plan view of Figure 1, Figure 4 is an enlarged view of the upper part of Figure 3, Figure 5 is an enlarged view of the lower part of Figure 3, Figure 6 is a view taken along line VI-VI of Figure 4, Figure 7 is an enlarged view in which the enlarged view within the circle in Figure 6 is replaced with a semi-finished flat body, Figure 8 is a view taken along line VIII-VIII of Figure 5, and is an enlarged view of a semi-finished flat body provided with a hot-dip galvanized layer, Figure 9 is a perspective view of the semi-finished flat body, Figure 10 is a perspective view of a completed truck after it has been shipped out of the truck manufacturer's production line, Figure 11 is a schematic side view of Figure 10, and Figure 12 is a schematic side view of Figure 11 with the semi-finished flat body attached. In order to make each figure easier to understand, the main parts are emphasized and parts that are not directly related to the present invention are omitted. The plate pieces for mounting the torii gate are omitted in Figures 3 and 4, and hatching of the cross-section of the plating layer is omitted except for the enlarged view of the circle in Figure 8.

[0012] (1) Semi-finished flat body The truck 9 is shipped from the truck manufacturer without a body. The semi-finished flat body P of the present invention is a flat body formed separately from the truck 9 shown in Fig. 11 and mounted on the frame 92 of the truck 9, and includes an iron ladder frame RF of a semi-finished flat body G before hot-dip galvanizing treatment, and a hot-dip galvanized layer 1 integrally coating the entire outer circumferential surface of the ladder frame. Here, "iron" in the iron ladder frame RF refers to a metal material such as steel containing iron components.

[0013] The ladder frame RF is an iron base part equipped with vertical joists 2, horizontal joists 3, and side rockers 4. At least two separated vertical joists 2 are crossed by a plurality of horizontal joists 3 and welded together in a ladder shape, and side rockers 4 are welded together at the end faces of the horizontal joists 3 that protrude outward on both sides beyond the vertical joists 2, forming a lattice-like ladder frame RF that is a vertically long rectangle in plan view (Fig. 3). The symbol ε indicates a lattice-like opening. In the present invention, the terms "upper" and "lower" refer to the upper and lower sides perpendicular to the paper surface in Fig. 3, and the front and rear of the vehicle refer to the upper and lower sides of the paper surface in Fig. 3.

[0014] The ladder frame RF is an iron lattice-like body elongated in plan view, in which two iron vertical joists 2 made of square cylindrical pipes are arranged approximately parallel to each other, as shown in Figs. 10 and 11, the ladder frame RF according to the semi-finished flat body P of the present invention is attached to two frames 92 of a truck 9 so that the two vertical joists 2 of the ladder frame RF are placed in the front-rear direction of the vehicle. Both the frame 92 and the ladder frame RF are provided with mounting plates (not shown), and the ladder frame RF can be attached and fixed to the frame 92 by bolting. A plurality of steel horizontal joists 3 made of rectangular cylindrical pipes are placed in a ladder shape at predetermined intervals on the two vertical joists 2, perpendicular to the vehicle width direction, as shown in the figures, and the vertical joists 2 and the horizontal joists 3 are welded together by applying L-shaped plates 72 as joist connectors to the side portions 24, 34 of the intersections. Through holes 20, 30 are provided at appropriate intervals on the undersides 22, 32 or side surfaces 24, 34 of the vertical joists 2 and horizontal joists 3 that constitute the ladder frame RF (Fig. 6). The vertical joists 2 and horizontal joists 3 are arranged in a ladder shape, and the side edges of the upper surface parts 41 of the side rockers 4 made of elongated steel members that have approximately the same length as the vertical joists 2 are joined to the end edges of the upper surface parts 31 on both sides of each horizontal joist 3 that protrudes outward from the vertical joists 2, and the joint parts j are welded together (Fig. 6), forming a lattice-shaped ladder frame RF that is vertically elongated in plan view.

[0015] 1 to 5, the ladder frame RF of this embodiment is further welded to a plurality of floor hooks 5, a plurality of center stanchion pockets 61, a plurality of side stanchion pockets 62, a center stanchion pocket 611 for a seat rope, a plate piece 73 for mounting the torii 8, a rope hook 75, and a bracket 74 for a side bumper. In addition, rectangular flat plates 71 each having a side length of about 1 / 3 of the vehicle width are welded to both side edges of the ladder frame RF at required locations, with the upper side edges of the plates welded to be approximately flush with the upper surface parts 31 of the horizontal joists 3 and the upper surface parts 41 of the side rockers 4. The floor hook 5 is a member for hooking a rope, belt or hook for securing luggage, and the floor hook 5 is a semi-arc-shaped ring that is rotatably attached to a bearing 51 fixed to the top surface 41 of the side locker (Fig. 4). Around the side locker 4 where the floor hook 5 is provided, a receiving plate piece 77 for receiving the floor hook 5 when it is lowered is welded to the side locker 4 while being kept almost flush with the top surface 41 of the side locker 4, and if the horizontal joist top surface 31 is nearby, it is also welded to this. Reference numeral 52 denotes a guard frame that stores and protects the floor hook 5 when it is lowered. The center stanchion pocket 61, the side stanchion pocket 62, and the center stanchion pocket 611 for the sheet rope are rectangular tubular, with the pocket openings that become the stanchion holes 610, 620, and 6110 facing upward, and each has an outer flange 76 near the upper end (FIG. 5). The upper surfaces of the outer flanges 76 are set to be substantially flush with the upper surface 31 of the horizontal joist 3 and the upper surface 41 of the side rocker 4 (FIGS. 2 and 8). The outer flanges 76 are welded to the horizontal joist 3 and the side rocker 4 so that the pocket openings that become the center stanchion hole 610, the side stanchion hole 620, and the stanchion hole 6110 for the sheet rope protrude slightly above the upper surfaces 31 and 41 of the horizontal joist 3 and the side rocker 4.

[0016] The plate piece 73 for mounting the torii 8 is an iron plate piece that can be used to detachably mount the separate torii 8 to the ladder frame RF with bolts and nuts. The plate piece 73 is welded to the horizontal joist 3 (or end bar member) in the width direction of the vehicle at the front end of the vehicle, and has a bolt hole 730 in the protruding part that protrudes upward (Figure 1). The rope hook 75 is a metal fitting as shown in the figure for fixing objects to the truck 9. Here, it is welded and fixed at an appropriate interval so that it protrudes downward from the lower part of the side rocker 4. It becomes the rope hook 75 around which the rope is wound. The side bumper bracket 74 is an angle member (equal leg angle iron) that is L-shaped when viewed from the side. The vertical part of the L-shape is welded and fixed to the side part 34 of the horizontal joist 3 that requires the bracket 74, and a through hole is provided in the protruding horizontal part.

[0017] On the other hand, the hot-dip galvanized layer 1 is a coating layer comprising an alloy layer formed from zinc and the iron base of the ladder frame RF by a film-forming technique of hot-dip galvanizing, the alloy layer bonding the zinc to the iron base, and integrally coating the entire outer circumferential surface of the ladder frame RF, and a pure zinc layer thereon. Galvanizing can be broadly divided into electrogalvanizing, which uses electricity to plate zinc, and hot-dip galvanizing, which immerses the steel ladder frame RF of the present invention in molten zinc to plate it. Unlike electrogalvanizing, hot-dip galvanizing, which forms the hot-dip galvanized layer 1, can be used for large products with a total length of about 10 m, such as the ladder frame RF of the present invention. Moreover, the ladder frame RF is immersed in a high-temperature zinc plating solution, and an alloying reaction occurs between the zinc and the steel base of the ladder frame RF, forming an alloy layer that strongly bonds the zinc and the steel base. Thus, the alloy layer, which cannot be obtained by painting or electrogalvanizing, also has the excellent effect of making the zinc plating less likely to peel off.

[0018] In this embodiment, the floor hooks 5, the pockets 61 for the center stanchions, the pockets 62 for the side stanchions, the pockets 611 for the center stanchions for the seat ropes, the plate pieces 73 for mounting the torii gates 8, the rope hooks 75, the brackets 74 for the side bumpers, and the rectangular flat plates 71 are all made of iron, and the ladder frame RF equipped with these has the hot-dip galvanized layer 1 formed on its outer peripheral surfaces as well as the vertical joists 2, the horizontal joists 3, and the side rockers 4. As described above, the lower surfaces 22, 32 or the side surfaces 24, 34 of the vertical joists 2 and the horizontal joists 3 constituting the ladder frame RF have through holes 20, 30 provided at appropriate intervals (FIG. 6). Therefore, when the plating layer 1 is formed by immersing the ladder frame RF in a molten zinc plating tank, the molten zinc smoothly penetrates not only the surface portions such as the upper surface portions 21, 31 and side surface portions 24, 34 of the ladder frame RF to be molten zinc plated, but also the inner surface portions 25, 35 of the square pipes of the vertical joists 2 and horizontal joists 3 which are exposed to the outside air, forming a coating 1a of the plating layer. The thickness of the hot-dip galvanized layer 1 formed on the entire outer surface of the ladder frame RF is about 50 μm to 100 μm. Compared to electrolytic galvanization, this method has the advantage of being able to make the layer much thicker, resulting in the desired semi-finished flat body P with excellent rust prevention properties. In the figure, reference numeral 91 denotes a cab and reference numeral 93 denotes a tire.

[0019] (2) Manufacturing method of semi-finished flat body The manufacturing method of the semi-finished flat body P is a manufacturing method of a flat body formed separately from the truck 9 and mounted on the frame 92 of the truck 9, in which a plurality of horizontal joists 3 are crossed and welded to at least two separated vertical joists 2 in a ladder shape, and side rockers 4 are welded to the end faces of the horizontal joists 3 that protrude outward on both sides beyond the vertical joists 2 to assemble into an iron ladder frame RF. Next, the ladder frame RF is immersed in a hot-dip galvanizing tank and then cooled to form a hot-dip galvanized coating 1a that is integrally coated on the entire outer periphery of the ladder frame RF.

[0020] In this embodiment, the above-mentioned floor hooks 5, the above-mentioned center stanchion pockets 61, the above-mentioned side stanchion pockets 62, the center stanchion pocket 611 for the seat rope, the plate piece 73 for mounting the torii 8, the rope hook 75, and the bracket for the side bumper 74 are further welded to the ladder frame RF. Then, the ladder frame RF to which these are joined is immersed in a hot-dip galvanizing bath and then cooled, so that the method for manufacturing a semi-finished flat body forms a coating film 1a of hot-dip galvanization integrally covering the entire outer peripheral surfaces of the floor hooks 5, the center stanchion pockets 61, the side stanchion pockets 62, the center stanchion pocket 611 for the seat rope, the plate piece 73 for mounting the torii 8, the rope hook 75, and the bracket for the side bumper 74, as well as the entire outer peripheral surfaces of the ladder frame RF that are in contact with the air.

[0021] The manufacturing method for the semi-finished flat body is to first complete the iron product of the ladder frame RF, which is a vertically long rectangle in plan view and has a total length of about 10 m, as shown in Figure 3. Here, the ladder frame RF is welded to which the floor hook 5, the pocket 61 for the center stanchion, the pocket 62 for the side stanchion, the pocket 611 for the center stanchion for the seat rope, the plate piece 73 for mounting the torii 8, the rope hook 75, and the bracket 74 for the side bumper are joined.

[0022] Next, the iron product of the ladder frame RF is immersed in a bath of molten zinc at a high temperature of about 440℃ to 450℃ for a predetermined time, and an alloy layer of iron and zinc is formed not only on the outer peripheral surfaces of the floor hooks 5, etc. and the outer peripheral surfaces of the top surfaces 21, 31, etc. of the ladder frame RF, but also on the inner peripheral parts 25, 35 of the vertical joists 2 and horizontal joists 3, which are rectangular tubes. Furthermore, a hot-dip galvanized coating 1a is integrally formed by coating the alloy layer on the outer peripheral surfaces of the floor hooks 5, etc. and the entire outer peripheral surface and inner peripheral parts 25, 35 of the ladder frame RF. In this way, a hot-dip galvanized coating 1a having a thickness of 50μm to 100μm is produced. As mentioned above, the vertical joists 2 and horizontal joists 3, which are made of square tubes, have through holes 20, 30 drilled therein, so that molten zinc flows smoothly into their inner surfaces 25, 35. Furthermore, when the floor hooks 5, the center stanchion pocket 61, the side stanchion pocket 62, the center stanchion pocket 611 for the seat rope, the mounting plate 73 for the torii 8, the rope hook 75, and the bracket for the side bumper 74 are provided, a molten zinc coating 1a is formed that integrally coats the entire outer peripheral surfaces of these components as well as the entire outer peripheral surface and the inner surfaces 25, 35 of the ladder frame RF.

[0023] After the hot dip galvanized coating 1a having the required thickness is formed, the desired semi-finished flat body P is completed by water cooling and / or air cooling.

[0024] The other components are the same as those in (1), and their explanation will be omitted. The same reference numerals as those in (1) indicate the same or corresponding parts. Incidentally, the iron torii 8, which is separate from the ladder frame RF, is also coated with a hot-dip galvanized coating 1a integrally on the entire outer periphery of the torii 8 in the same manner as the ladder frame RF.

[0025] (3) Effects In the semi-finished flat body and its manufacturing method configured in this manner, when the hot-dip galvanized layer 1 is provided integrally covering the entire outer peripheral surface of the iron ladder frame RF, a zinc-plated passive film 1a is formed on the outer peripheral surface of the ladder frame RF, which prevents the intrusion of air and water into the iron base of the ladder frame RF and provides an anti-rust effect. Furthermore, unlike painting or electroplating, hot-dip galvanizing forms an alloy layer by a chemical reaction between zinc and iron material, which strongly bonds the zinc and iron material, making the plating less likely to peel off and resulting in a ladder frame RF with a hot-dip galvanized layer 1 that has excellent rust prevention effects for a long period of time.

[0026] Furthermore, since the hot-dip galvanized layer 1 can have a thicker film 1a than an electrolytic galvanized layer, it is ideal for the semi-finished flat body P that is placed in a harsh outdoor environment. In addition, even if the galvanized layer 1 is scratched and the iron ladder frame RF is exposed, the zinc around the scratch dissolves before the iron does and provides electrochemical protection, providing an excellent effect of preventing the iron ladder frame RF from rusting. In particular, the rust problem has become more serious in recent years as calcium chloride, a snow-melting agent used in winter, has come to be used widely and in large quantities throughout the country.Under these circumstances, a semi-finished flat body P in which a large steel ladder frame RF with a total length of approximately 10m is immersed in a hot-dip galvanizing bath to form a hot-dip galvanized layer 1 that exerts the above-mentioned excellent effects on the entire outer surface of the ladder frame RF has never existed before, and this is a groundbreaking invention in improving the durability of steel ladder frames RF.

[0027] Furthermore, when the ladder frame RF is manufactured as in the present invention and a hot-dip galvanized layer 1 is provided on it to make a semi-finished flat body P, the product is provided in a state where the ladder-shaped base part, which requires difficult assembly techniques in the manufacture of the flat body, is already assembled, which has excellent effects on the standardization of the quality of the flat body, optimization of the equipment, and shortening of delivery times. For example, it is the difference between a house built by a carpenter and a modular house produced in a quality-controlled factory, and a consistent quality is ensured regardless of the skill of the craftsman. Also, even if a mounting factory does not have the technology to build a body from scratch, it has the advantage of being able to manufacture flat-body vehicles by using this semi-finished body. A mounting factory that receives the semi-finished flat body P of the present invention can simply attach and fix the semi-finished flat body P to the frame 92 of the truck 9 in Figure 11 as shown in Figure 12, and then attach the gates 8, tailgates m, floor panels, etc. according to the orders of each user (transport company), and can easily complete a flat-body vehicle.

[0028] And by deliberately leaving it semi-finished as in the present invention, the semi-finished flat body P can be made to meet the special requirements of each user (transportation company). This enables optimization of equipment. Since we provide a standardized product of the semi-finished flat body P, which is based on the base of the flat body, we can flexibly respond to special orders from end users. If a semi-finished flat body P in which a plurality of floor hooks 5, a plurality of center stanchion pockets, and a plurality of side stanchion pockets are welded to the ladder frame RF, and in which the outer circumferential surfaces of all of these are integrally coated with the hot-dip galvanized layer 1, were to be standardized and offered for sale, it would be possible to eliminate the trouble of welding these parts together later, and also to avoid damage to the hot-dip galvanized layer 1 that would otherwise accompany welding, resulting in a more preferable semi-finished flat body P. Incidentally, there is no standard shape for the torii 8 in terms of its height, the presence or absence of a seat deck, the shape of the side ladder, etc. Therefore, the torii 8 is constructed separately from the semi-finished flat body P, making this an invention that can meet various custom requests for the torii 8. By not including the torii 8 in the semi-finished flat body P, there is also the advantage that it becomes easier to immerse the ladder frame RF, which is the semi-finished flat body G before the plating process, in the hot-dip galvanizing treatment tank.

[0029] In addition, the production period for a prefabricated body at a body factory is about 3 to 4 months, but by using the semi-finished flat body P of the present invention, the production period can be significantly shortened. Since the semi-finished flat body P of the present invention serves as the foundation, which is the most important and requires the most skill in manufacturing a flat body, it can be produced even at bodywork factories that have never produced prefabricated bodies before or at factories that can no longer take on the job due to a shortage of craftsmen, making this an excellent invention that is expected to dramatically improve delivery times, quality, etc. in the future. Thus, the semi-finished flat body and the method for manufacturing the same exhibit the various excellent effects described above and are extremely beneficial.

[0030] The present invention is not limited to the above embodiment, and can be modified in various ways within the scope of the present invention according to the purpose and use. The shape, size, number, material, etc. of the plating layer 1, vertical joists 2, horizontal joists 3, side rockers 4, floor hooks 5, center stanchion pocket 61, side stanchion pocket 62, mounting plate 73 for torii 8, bracket 74 for side bumper, rope hook 75, etc. can be appropriately selected according to the use. [Explanation of symbols]

[0031] 1. Hot-dip galvanized layer (plated layer) 1a Hot-dip galvanized coating (coating) 2 Vertical joists 3 Horizontal joists 4 Side Rocker 5 Floor Hooks 61 Center stanchion pocket 62 Side stanchion pocket 9 Tracks 92 frames P Semi-finished flat body (Semi-finished flat body) G Semi-finished flat body before hot-dip galvanizing treatment

Claims

1. A semi-finished flat body that is formed separately from a truck and is mounted on a frame of the truck, A semi-finished flat body comprising an iron ladder frame in which a plurality of horizontal joists are crossed and welded to at least two spaced apart vertical joists in a ladder shape, and side rockers are welded to the end faces of the horizontal joists that protrude outward on both sides beyond the vertical joists, and a hot-dip galvanized layer that integrally covers the entire outer periphery of the ladder frame.

2. 2. The semi-finished flat body according to claim 1, wherein a plurality of floor hooks, a plurality of center stanchion pockets, and a plurality of side stanchion pockets are welded to the ladder frame, and the outer peripheral surfaces of all of these are integrally coated with the hot-dip galvanized layer.

3. A method for manufacturing a semi-finished flat body of a flat body which is formed separately from a truck and is mounted on a frame of the truck, comprising the steps of: A method for manufacturing a semi-finished flat body, comprising the steps of: crossing a plurality of horizontal joists around at least two spaced apart vertical joists and welding them together in a ladder shape; further welding side rockers to the end faces of the horizontal joists that protrude outward on both sides beyond the vertical joists to form an iron ladder frame; and then immersing the ladder frame in a molten zinc plating tank and cooling it to form a molten zinc plating coating that is integrally coated on the entire outer peripheral surface of the ladder frame.

4. 4. A method for manufacturing a semi-finished flat body as described in claim 3, further comprising welding and connecting a plurality of floor hooks, a plurality of center stanchion pockets, and a plurality of side stanchion pockets to the ladder frame, immersing the ladder frame thus connected in a hot-dip galvanizing tank and then cooling the same to form an integrated hot-dip galvanizing coating on the entire outer peripheral surfaces of the ladder frame as well as the entire outer peripheral surfaces of the floor hooks, the center stanchion pockets, and the side stanchion pockets.

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