Background of the invention

The invention relates to a fastening element for connecting frame parts of a vehicle to each other. The fastening element is an angle element by means of which crossed frame parts are mountable to each other in the area of the corners between the frame parts.

Further, the invention relates to an arrange ^¬ ment in a frame structure of a vehicle, the arrange ^¬ ment applying the fastening element as disclosed.

The field of the invention is described in more detail in the preambles of independent claims of the application.

The frames of vehicles, such as buses, may be built by connecting beams and other frame parts of a desired profile to each other. The corners between crossed beams may be provided with angle elements and suchlike fastening elements for fastening the beams to each other and for strengthening the connection. However, it has been found that there are drawbacks in the currently used fastening elements.

Short description of the invention

The object of this invention is to provide a new and improved fastening element and arrangement in a frame structure of a vehicle.

The fastening element according to the invention is characterized by the features defined in the characterizing part of the first independent claim of the application.

The arrangement according to the invention is characterized by the features defined in the charac ^¬ terizing part of the second independent claim of the application. The idea of the disclosed solution is that the fastening element comprises two flanges positioned perpendicular to each other, such that the fastening element is shaped as an angle element. Thus, the flanges form an external angle side and an internal angle side for the fastening element. The flanges are provided with fastening holes for fastening of the fastening element to the frame parts of a vehicle. Further, the thickness of both of the flanges is ar- ranged to be greater in proximity to the angle between the flanges than at the free ends of the flanges; in other words, the flanges taper at the internal-angle- side surfaces towards the outermost portion of the flanges .

The advantage of the disclosed solution is that the structure of the fastening element has been designed by taking into account the loads applied to it during use. That is to say, the areas of the fas ^¬ tening element in proximity to the corner are subject to a greater load during use than the areas of the free ends of the flanges, and therefore the thickness and thereby strength of the flanges is arranged to be greater in proximity to the corner of the fastening element. The areas of the ends of the flanges, in- stead, are subject to a smaller load, so their materi ^¬ al thickness may be smaller. Thus, material has been directed in the fastening element only to the areas where it is needed, such that no excess material is added to the fastening element. Thus, the fastening element may be light and yet very robust.

The idea of one embodiment is that both of the flanges of the fastening element comprise two fas ^¬ tening holes at a distance from each other. Further, on the internal-angle-side surface, i.e. the second surface of each of the flanges, there are plane sur ^¬ faces in the area of the fastening holes. Also, the adjacent plane portions on each of the flanges are spaced at unequal distances from the first surfaces of the flanges, so the thickness of the flanges is une ^¬ qual at the adjacent fastening holes. Between the plane portions of the flanges there is a transitional portion that has a slanted or a curved shape. This type of transitional portion where the thickness of the structure changes smoothly is beneficial in terms of the strength of materials. The plane portions in the area of the fastening holes serve as good abutment surfaces for the support surfaces of the heads of fas ^¬ tening screws.

The idea of one embodiment is that the fas ^¬ tening element is a symmetrical element. Thus, both of the flanges are substantially similar in shape and size .

The idea of one embodiment is that the fas ^¬ tening element is mountable to a corner between two crossed frame elements by screw mounting.

The idea of one embodiment is that the fas- tening element is fastened to the frame element by means of screw mounting comprising fastening screws. Each of the fastening screws is arranged through a fastening hole and tightened against a mating element having threaded holes. The mating element may be ar- ranged in a groove on the mounting surface of the frame element, and then turned to a position where it is no longer able to come out through the groove. This type of shape-locked mating element is easy to arrange in its place through the groove. Alternatively, the mating element is arranged in the groove from one end of the beam or the frame part, and is pushed in the longitudinal direction to its place facing the fas ^¬ tening element.

The idea of one embodiment is that the mating element comprises holes for two fastening screws; in other words, one mating element may function as a mat ^¬ ing element for both of the fastening screws of one flange. Alternatively, there is a proper mating ele ^¬ ment for each of the fastening screws.

The idea of one embodiment is that the mount ^¬ ing surfaces of the fastening element comprise align- ment projections in the longitudinal direction of the flanges. These alignment projections may be located on the centre axis of the flanges. The alignment projec ^¬ tions may be sized according to the dimensions of the mounting grooves on the frame parts to be connected, such that the alignment projections may penetrate into the mounting grooves. Thus, the mounting grooves and the alignment projections align the beams to be con ^¬ nected in precisely right directions without special components and orientation. This way, accurately ori- ented connections can be implemented even by less ex ^¬ perienced and skilled mechanics. Furthermore, instal ^¬ lation is quick, as no extra measurements and instal ^¬ lation templates are needed.

The idea of one embodiment is that the mount- ing surfaces of the fastening element comprise align ^¬ ment projections arranged in the longitudinal direc ^¬ tion of the flanges and having slanted or wedge-shaped surfaces. These wedge surfaces lie at a slanted angu ^¬ lar position relative to the side surface of the beam to be connected, and they are set against the surfaces of the mounting groove on the beam. This type of wedge surface provides a stable and shape-locked connection. Similarly, the mating elements used for connecting the fastening element may comprise slanted or wedge-shaped locking surfaces, supported to the mounting groove from the inner-surface-side of the beam. When both of the alignment projections and the mating elements com ^¬ prise shaped surfaces according to this embodiment, a particularly stable connection may be achieved, where forces are also supported by means of shape-locking.

The idea of one embodiment is that the align ^¬ ment projections extend continuously from the outer- most ends of the flanges up to the angle between the flanges .

The idea of one embodiment is that the flang ^¬ es comprise at least two alignment projections at a distance from each other on the centre axis of the flanges .

The idea of one embodiment is that on both sides of the alignment projection there are plane abutment surfaces arranged to lie against the outer surface of the frame component to be connected.

The idea of one embodiment is that the fas ^¬ tening element is made from aluminium or an aluminium alloy. Aluminium is a light and corrosion-resistant metal material and is therefore well suited for use in vehicles.

The idea of one embodiment is that the fas ^¬ tening element is manufactured by cutting a piece from an elongated extruded preform bar in its transverse direction, the length of the piece corresponding to the width of the flanges. By extrusion, a dimensional- ly accurate preform bar having a good surface quality and homogeneous material structure may be manufac ^¬ tured. This type of preform bar has good strength properties. Angle element preforms of a desired width may be easily cut from the preform bar and provided with the fastening holes. Extrusion is also a quick and efficient manufacturing method, by means of which the fastening elements may be manufactured at a com ^¬ petitive price. The fastening holes may be drilled on the flanges of the angle element preform, and the alignment projections may be worked on the external- angle-side surfaces of the flanges in the longitudinal direction of the flanges by milling or other material- removing machining process. The preform bar may be ex- truded for example from aluminium or an aluminium alloy . The idea of one embodiment is that the mating elements for the fastening screws are also manufac ^¬ tured by cutting a piece of a desired length from an extruded aluminium preform bar. After cutting, the preforms are provided with holes and threads for the fastening screw.

The idea of one embodiment is that the fas ^¬ tening element is formed by an additive manufacturing process, such as by printing.

The idea of one embodiment is that the fas ^¬ tening element is of plastic or a composite material, such as reinforced plastic.

The embodiments described above and their in ^¬ dividual features may also be combined to provide a desired fastening element and fastening arrangement.

Brief description of the figures

Some embodiments of the solution are de ^¬ scribed in more detail with reference to the accompa- nying drawings, in which

Fig. 1 schematically illustrates one fas ^¬ tening arrangement for a frame of a vehicle, where fastening elements are arranged at corners between crossed beams by means of screw mounting,

Fig. 2 schematically illustrates one fas ^¬ tening element having the shape of an angle element,

Fig. 3 schematically illustrates a perspec ^¬ tive view of one fastening element, where fastening screws inserted in fastening holes have been driven into threaded holes arranged in mating elements,

Fig. 4 schematically illustrates part of one extruded elongated preform bar, from which preforms of the fastening element may be formed by cutting a piece of a desired length,

Fig. 5 schematically illustrates one fas ^¬ tening element after it has been provided with fas ^¬ tening screws and mating elements, Fig. 6 schematically illustrates an enlarge ^¬ ment of one connection between beams,

Fig. 7 schematically illustrates one fas ^¬ tening element as seen perpendicularly to the mounting surface of one of the flanges, and

Fig. 8 schematically illustrates yet another view of a connection between a longitudinal beam and a crossbeam.

In the figures, some embodiments are illus- trated in a simplified form for clarity purposes. Like parts in the figures are indicated by the same num ^¬ bers .

Detailed description of some embodiments

Fig. 1 illustrates a fastening arrangement 1 for a frame of a vehicle, where several beams disposed in the same plane are fastened to each another by means of fastening elements 3. This type of arrange ^¬ ment may be present for example in the frame structure of the chassis of a bus or a similar vehicle. The frame may comprise two longitudinal beams 2a, 2b, be ^¬ tween which there is arranged a crossbeam 2c and, as extension of beam 2c, beams 2d and 2e. At corners 4 between the beams there are arranged fastening ele- ments 3 by means of screw mounting. Further, the ends of the longitudinal beams 2a, 2b may be fastened to a single crossbeam 2f by means of the fastening elements 3. As can be seen in Fig. 1, the sides of the beams 2a - 2f may be provided with mounting grooves 5, in which there may be arranged mating elements for the screw mounting of the fastening elements 3. Of course it is possible also to use beams with other profiles, and it is not necessary to provide them with any mounting grooves at all.

As can be seen in Fig. 2, the fastening element 3 is a type of angle element with two flanges, a first flange 6a and a second flange 6b, and an angle 7 between them. Thus the fastening element 3 has an external angle 7a, and its flanges 6a, 6b have external- angle-side first surfaces 8a, and correspondingly an internal angle 7b and internal-angle-side second sur- faces 8b. The internal angle 7b may be rounded, as shown in the figure. The flanges 6a, 6b have a greater first thickness Dl in proximity to the corner 7 and a smaller thickness D2 in proximity to the ends of the flanges, i.e. the flanges taper in a direction away from the corner 7. Further, the flanges 6a, 6b comprise fastening holes 9 extending through the structure. In the area of the fastening holes 9, on the side of the second surfaces 8b, there may be plane portions or surfaces 10, against which it is good to tighten the fastening screws. Between the adjacent plane surfaces 10 there may be a slanted or curved transitional portion S. On the side of the first sur ^¬ faces 8a of the flanges 6a, 6b there may be elongated alignment projections 11 that may extend from the outermost part of the flanges up to a chamfer 12 at the external corner 72. Outermost end surfaces 13 of the flanges 6a, 6b may be rounded.

Fig. 3 shows that the fastening holes 9 on the flanges 6a, 6b of the fastening element 3 may be provided with fastening screws 14. The fastening screws 14 may be tightened against mating elements 15 having threaded holes 16. A profile P of the mating element 15 may be selected such that it corresponds to the mounting groove defined by the profile of the beam to be connected.

Fig. 4 illustrates the end part of a preform bar 17 formed by extrusion. From the preform bar 17, preform pieces 18 of a desired width may be cut, and they may be further processed into fastening elements. Cutting points 19 are indicated with a dashed line, as well as the points at which the fastening holes 9 are drilled. At the finishing stage, the preform pieces 18 may also be provided with alignment projections, be ^¬ cause they cannot be formed during extrusion.

Fig. 5 illustrates the solution described above with reference to Fig. 3 from a different angle.

Fig. 6 illustrates the arrangement 1 where the beams 2 are connected to each other by means of the fastening elements 3, the fastening screws 14, and the mating elements 15 arranged in the grooves 5.

Fig. 7 illustrates the solution as shown in Fig. 3 and 5 from yet another alternative angle.

Fig. 7 shows that the alignment projections 11 on the fastening element 3 may comprise first coni ^¬ cal surfaces or wedge surfaces Kl, and the mating ele ^¬ ments 15 may correspondingly comprise second conical surfaces or wedge surfaces K2. During tightening, these wedge surfaces Kl and K2 are set against the surfaces of the mounting grooves 5 of the beams 2, such that the elements 2, 3 and 15 are tightly locked together, and the connection may bear, by means of shape-locking, shear forces in the vertical direction, and the bending moment and torque during bending.

Fig. 8 illustrates one fastening arrangement 1 between two beams 2b and 2c. The principles de ^¬ scribed above are applied in the arrangement.

In some cases, the features described in this application may be used as such, irrespective of other features. On the other hand, the features described in this application may be combined, if necessary, in order to form various combinations.

The drawings and the accompanying description are only intended to illustrate the inventive idea. The details of the invention may vary within the scope of the claims.