WO2002098702A1

WO2002098702A1 - Haulage rack

Info

Publication number: WO2002098702A1
Application number: PCT/FI2002/000490
Authority: WO
Inventors: Simo-Pekka Sainio
Original assignee: Simo-Pekka Sainio
Priority date: 2001-06-06
Filing date: 2002-06-06
Publication date: 2002-12-12
Also published as: FI20011190A0; FI20011190A

Abstract

The invention relates to a transport bunk structure for transportation of logs (12). The transport bunk (10) comprises a bunk frame (13) with vertical stakes (14, 14') adapted at both ends therof. At least the construction of the bunk frame (13) comprises two opposedly oriented U-sections (17, 18) joined to each other at their flanges (19, 20; 19', 20'). A connecting web (21) extending over the entire length of the U-sections (17, 18) is attached parallel to the main webs (17', 18') of the U-sections (17, 18) so as to span between the flanges (19, 20; 19', 20') of the section.

Description

Haulage rack

The invention relates to a haulage rack and more precisely to its bunk structure intended for mounting on vehicle chassis particularly suited for log transportation, the transport bunk comprising a bunk frame with vertical stakes adapted at both ends thereof, whereby at least the construction of the bunk frame comprises two opposedly oriented U-sections joined to each other at their flanges.

Conventionally, transport bunk structures are made from a tubular continuous section or from different kinds of structural steel sections such as a continuous U-section, for instance. In addition to steel, also aluminum is used as the structural material. The main components of a transport bunk structure are the bunk frame having its both ends complemented with vertical stakes that may optionally be adapted removable. The bunks are mounted on the vehicle chassis by suitable fixtures either stationary or in a movable fashion. In Finnish utility model registration no. 1440 is disclosed a conventional transport bunk structure and particularly the bunk frame thereof. According to cited utility model registration, the bunk frame is made from steel plates that are welded into a beam structure.

Steel bunk constructions are heavy and their center of gravity is situated quite high. Aluminum bunks are obviously lighter than those made of steel, but they have a lower resistance to blows and reversing stress. However, transport bunks of either material are unsatisfactory in their resistance to blows, whereby they are readily subject to corrosion. This makes the service life of transport bunks short in spite of surface treatments. Moreover, the bunk frame disclosed in cited utility model application is complicated to fabricate and may deform beyond its ultimate strength under excess load situations.

It is an obj ect of the present invention to provide a transport bunk that has a strength- to-weight ratio higher than in prior-art constructions and simultaneously an extended service life in regard to conventional bunks, yet featuring easier fabrication than is required in the making of prior-art constructions. The characterizing features of the present invention will be evident from appended claims. As to the load-bearing capability, the structure of the transport bunk according to the invention is extremely advantageous. The manufacture of the bunk uses purpose-designed continuous section parts that are combined so as to form a transport bunk according to the invention. Complemented with proper selection of construction materials, a lightweight yet strong and durable transport bunk is provided. In spite of its higher service capability, the transport bunk according to the invention is uncomplicated and cost- efficient to manufacture.

Next, the invention will be examined in greater detail by making reference to the appended drawings illustrating certain applications of the invention, wherein

FIG. la shows a side elevation view of a truck having transport bunks according to the invention mounted on its bed;

FIG. lb shows a front view and a side elevation view of a part of the transport bunk according to the invention during its manufacture;

FIG. 2a shows a front view and a side elevation view of the transport bunk according to the invention after completion of its manufacture;

FIG. 2b shows a cross section of the stake portion of the transport bunk of FIG. 2a taken along plane A-A;

FIG. 2c shows a cross section of the frame portion of the transport bunk of FIG. 2a taken along plane B-B;

FIG. 3a shows an axonomerric view of the junction of frame and stake portions in an alternative embodiment of the transport bunk according to the invention;

FIG. 3b shows a cross section of the stake portion of the transport bunk of FIG. 3a; and

FIG. 3 c shows a cross section of the frame portion of the transport bunk of FIG. 3 a.

Referring to FIG. la, therein are illustrated transport bunks 10 mounted on a trailer truck 11. Later in the text, the transport bunks are simply called bunks. As shown in FIG. la, a bunk 10 according to the invention is purpose-designed for the transport of green logs 12, such a use of bunks being generally familiar to those versed in the art.

FIG. 2a shows the front and side elevation views of a ready-for-use bunk 10. The bunk 10 comprises a bunk frame 13 with vertical stakes 14 and 14' adapted to its both ends. The joints between the bunk frame 13 and the stakes 14 and 14' are complemented with stiffening plates 15 serving to improve the strength of the bunk. Accordingly, this embodiment employs permanently fixed stakes. For mounting on a vehicle chassis, the bunk 10 is provided with drilled plates 16 attached to the underside of the bunk frame 13.

FIG. 2c shows the cross section of the bunk frame. A major portion of bunk frame 13 is formed by two U-sections 17 and 18 that are opposed to each other and joined with each other by their flanges 19, 20 and 19', 20'. The reference numerals of the flanges are denoted in FIG. 3c. According to the invention, an additional connecting web 21 extending over the entire length of the U-sections 17 and 18 is attached parallel to the main webs 17' and 18' of the U-sections 17 and 18 so as to span between the flanges 19, 20 and 19', 20' of the section. By virtue of having the flanges of the U-sections connected to each other with the help of the connecting web, a box-section structure of a very high strength is formed. Furthermore, the connecting web makes deformations of the bunk frame very unlikely. Thus, the connecting web prevents bulging or buckling of the U-sections.

Advantageously, also the structure of both vertical stakes 14 and 14' is made similar to that of the bunk frame 13. To this end, the vertical stakes 14 and 14' are fabricated from purpose-designed U-sections 28 and 29 complemented with connecting webs 21'. Fabricated in this fashion, the structures of the bunk frame and the vertical stakes are inherently strong. Having the stakes connected to the bunk frame in the fashion of the present invention, a bunk structure is provided offering a uniform strength. The fabrication of the bunk is commenced, by welding the connecting webs 21 and 21' of both the bunk frame 13 and the vertical stakes 14 and 14' to each other. This step is illustrated in FIG. lb. Next, the U-sections are accurately aligned with the connecting webs and then welded with continuous seams so that the U-sections both of the bunk frame and the vertical stakes, as well as the connecting webs, are connected to each other. In this fashion, the fabrication of both the vertical stake and the bunk frame becomes easier inasmuch as only two long continuous welds 22 and 23 have to be made. Simply, a single weld need to be made to join three prefabricated plate parts with each other. Finally, the bunk is complemented, by welding thereon the stiffening plates 15 and possible mounting accessories. In fact, as shown in FIG. 3a, the stiffening plates may be omitted due to the increased strength.

In addition to the above-described optimized construction, a greater strength of the novel bunk is attained by virtue of proper material selection. According to the invention, both the U-sections and the connecting webs are made from extra-high-strength stainless steel sheet. As known, this type of construction material has a long life without any surface treatment. In accordance with its name, the material is really tough having excellent strength under reversed loads and impacts. All the parts needed in the assembly are made from sheets by bending their edges, which technique gives certain benefits. Namely, the bending of the edges of extra-high-strength steel plate gives additional toughness to the material, whereby also the overall structure becomes stronger. According to the invention, the flanges 19, 20 and 19', 20' of each one of the U-sections 17 and 18 as well as 28 and 29 are worked to include second corners 26 and 27 at which the flanges 19, 20 and 19', 20' are bent inwardly in the finished bunk section. In this context, inwardly means a direction oriented toward the cargo space formed by the bunks. Additionally, the first bends 24 and 25 serve to outdistance the flanges 19, 20 and 19', 20' of the U-sections 17 and 18 and, respectively, 28 and 29, from their main webs 17' and 18'. The second bends 26 and 27 serve to increase the strength of the finished bunk structure to provide a butt surface for joining to the connecting web. An additional feature is that in a finished bunk 10, the inward bends 24 and 26 are angled by more than 90°. In this context, inward as a term again refers to a direction oriented toward the cargo space formed by the bunks. The purpose of using an edge bent by more than 90° is to make the flanges 19 and 19' sufficiently strong.

FIGS. 3a - 3c show an alternative embodiment of the present bunk structure. Herein, the second inward bends 26 are arranged so that the edges of the corresponding flanges 19 and 19' extend beyond the level defined by the first bends 24. Thus, the edges of the flanges 19 and 19' form an anti-slip surface capable of preventing the cargo from moving in the longitudinal direction of the transport vehicle. In the first embodiment, the corresponding anti-slip surface is implemented by means of an upward-open U-section 30 welded on the top side of the bunk frame 13. In contrast, the alternative embodiment provides such an anti-slip surface naturally on vertical stakes as well, whereby the stability of the cargo is further improved. For greater clarity, same numerals are used in the diagrams for equivalent elements.

In both embodiments, the second bends 27 made on the external sides of the bunk/stake sections are angled by 30° to 60°, advantageously by 40° to 50°. The second bends 27 serve to reduce the height of the connecting web 21 and 21 ', whereby also the welding of seams 22 and 23 becomes easier. In fact, the underside of the bunk frame and the exterior side of the stakes need not be very strong, since these parts of the section are subjected to compressive stress only in a loaded vehicle. In contrast, the construction according to the invention provides substantial strength on the top side of the bunk frame and the interior side of the stakes, where the structures are subjected to high tensional stresses.

In a practicable embodiment of a bunk structure according to the invention, the U- sections were made from a 3 mm thick sheet of extra-high-strength stainless steel. The connecting webs were made from a 4 mm thick sheet. Using these material dimensions, the torsional stiffness and strength of the bunk was substantially im- proved over the prior art, yet having a lighter construction than that of conventional bunks. In fact, the overall weight of a finished bunk was about 100 kg, while a conventional bunk weighs about 150 kg. The overall weight of the present construction is also reduced, by making the vertical stakes upward tapering. For greater clarity, the upward tapering shape of the stakes is slightly exaggerated in the diagrams. In a practicable construction, the stakes taper by about 30 mm toward their upper end. As a whole, the bunk according to the present invention is extremely durable and easy to use. Uncompromisingly, the present bunk construction offers lighter weight and easier manufacture over prior-art embodiments.

Claims

What is claimed is:

1. A transport bunk structure intended for mounting on vehicle chassis (11) particularly suited for transportation of logs (12), the transport bunk (10) comprising a bunk frame (13) with vertical stakes (14, 14') adapted at both ends thereof, whereby at least the construction of the bunk frame (13) comprises two opposedly oriented U- sections (17, 18) joined to each other at their flanges (19, 20; 19', 20'), characterized in that a connecting web (21) extending over the entire length of the U-sections (17, 18) is attached parallel to the main webs (17', 18') of the U-sections (17, 18) so as to span between the flanges webs (19, 20; 19', 20') of said U-sections.

2. The transport bunk of claim 1, characterized in that the structure of either one of said vertical stakes (14, 14') is similar to that of the bunk frame (13) as to the U- section (28, 29) and the connecting web (21 ').

3. The transport bunk of claim 1 or 2, characterized in that the connecting webs (21, 21') of the bunk frame (13) and the vertical stakes (14, 14') are joined to each other by welding.

4. The transport bunk of claims 1 - 3, characterized in that the U-sections (17, 18; 28, 29) of both the bunk frame (13) and the vertical stakes (14, 14') are joined to each other and the connecting webs by welding.

5. The transport bunk of any one of claims 1 - 4, characterized in that the U- sections (17, 18; 28, 29) and the connecting webs (21, 21') are made of extra-high- strength stainless steel sheet.

6. The transport bunk of any one of claims 1 - 5, characterized in that in each one of the U-sections (17, 18; 28, 29) the edge portions of the flanges (19, 20; 19', 20') are provided with second edge bends (26, 27) in order to align the edge portions of the lateral webs (19, 20; 19', 20') in the finished transport bunk structure (13) so as to be directed inwardly toward the bunk system cargo space.

7. The transport bunk of claim 6, characterized in that in a finished bunk structure (13) the inward edge bends (24, 26) are angled by more than 90°.

8. The transport bunk of claim 6 or 7, characterized in that the second inward bends (26) are adapted so as to make the edges of said flanges (19, 19') to extend beyond the level defined by the first bends (24).

9. The transport bunk of claim 8, characterized in that the second bends (27) made on the external side of the bunk/stake sections are angled by 30° to 60°, advantageously by 40° to 50°.

10. The transport bunk any one of claims 1 - 9, characterized in that an upward- open U-section (30) is mounted on the top side of said bunk frame (13).