Abstract:
Wooden framework building system consisting of semi-finished industrial product formed of glued boards. The construction according to the invention is made from only two bearing elements forming sill ( 1 ), purlin ( 2 ), ledge ( 4 ) and post ( 3 ). The cross-sections of the two bearing elements have each one side of the same size. The sizes for each particular case are determined by the requirements of the projects and plans, the statistical and physical aspects of the construction. To provide for an accurate, undismountable and resistant connection of the construction elements two dowels ( 9 ) are used per assembly. The lengths of the construction elements are determined from the module selected for the horizontal, respectively vertical elements.

Description:
FIELD OF THE INVENTION 
     The present invention relates to a wall frame system of framework construction for a building, in which the frame components of the wall frame are joined together via splayed notch joints and in which each frame component is provided with markings to facilitate installation. 
     BACKGROUND OF THE INVENTION 
     In prior art, roughed-out framing systems for wooden buildings are known in which, to facilitate installation, the various parts of the framework are prefabricated prior to being transported to the building site. DE specification 35 12 306 A1 presents a lattice-like frame structure in which the vertical components of each wall frame are joined to a top or bottom stringer via a mortise and tenon joint in which both the horizontal top and bottom stringers and the vertical component are provided with round holes into which separate round tenons are fitted. In joints connecting adjacent wall frames at right angles to each other, mortise and tenon joints are used in the top stringers in which e.g. a central mortise of a rectangular cross-section is made in the top side of the top stringer and the end of the wall component to be joined with it is then fitted into this mortise. The task of joining individual components together can be facilitated by providing them with markings allowing the right components to be joined to each other. This prior-art solution has the drawback of being complex and slow. Drilling small holes for the mortise and tenon joints at exactly the correct positions requires great precision and plenty of time. U.S. Pat. No. 5,170,600 presents a prefabricated housing addition in which dovetail joints are used to connect wall frame components to each other and also to other parts of the wall frame. A drawback with this solution is difficult installation, because adapting the dovetail joint so that it will be set in the correct position at both ends of the component at installation time is very difficult. Moreover, both of the aforementioned solutions are only used for rectangular joints in which the frame components are at right angles to each other. 
     SUMMARY OF THE INVENTION 
     The object of the present invention is to eliminate the drawbacks of prior-art solutions and to achieve a new type of wall frame system in which the marking on each frame component is an identifying code printed on its surface that identifies the frame component in accordance with the construction plan, and in which the notch joint consists of a notch tapering toward its bottom and a main piece fitted into it. 
     The apparatus of the invention comprises a conveyor for conveying the frame component between different machining stages, a cutting station wherein the wooden parts are cut by machine to predetermined dimensions according to the construction plan, as well as a control unit for controlling the machining operations. Moreover, the apparatus of the invention comprises a computer which can be connected to the control unit and which determines for each frame component an individual code based on the basic data for the building, a printing device, such as an ink jet printer, for printing the code on the surface of the frame component, and a milling apparatus for making the notches tapering towards the bottom as well as the main pieces to be fitted into them. 
     The system of the invention enables industrial fabrication of diversiform buildings. The building method does not impose any restrictions on architecture. The system of the invention allows easy construction of stepped structures and structures of changing height. 
     Using the system of the invention, the installation of a wooden framework for a building can be made significantly easier and faster. The markings on the frame components give a detailed definition of the type and properties of the component in question. Moreover, the notches in the component and the notch markings exactly and unambiguously define the position of the component to be joined in a particular notch. The notches, being made in exactly the right positions, add to the rigidity of the wall structure. In addition, the system of the invention allows the making of diagonal joints. As the measurements are defined relative to the centre of the notch, no measurement errors can occur even in the case of diagonal joints. 
     Moreover, the apparatus of the invention provides a better possibility than prior-art techniques to fabricate the wooden framework of a building from premachined frame components cut to size and provided with the required markings using a single apparatus directly on the building site, thus reducing storage costs and space requirements. 
     The dimensioning of the wooden frame can be effected e.g. using CAD software to control an automatic machining line that cuts all components and provides them with precise markings and notches so as to make them ready for installation, taking the requirements of frame post spacing, insulation and panelling into account. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     In the following, the invention will be described in detail by the aid of an example by referring to the attached drawings, in which 
     FIG. 1 presents a wall frame of framework construction of changing height according to the invention, 
     FIG. 2 presents a frame component according to the invention, 
     FIGS. 3,  4   5 ,  6   a  and  6   b  present notch joints according to the invention, 
     FIG. 7 a  and  7   b  are more detailed illustrations of the notch joint of the invention, 
     FIG. 8 presents an apparatus according to the invention, 
     FIGS. 9 a  and  9   b  present a turnable milling unit comprised in the apparatus of the invention, as seen from the direction of the transverse axis and in front view, 
     FIG. 10 presents a turnable milling unit comprised in the apparatus of the invention as seen from the direction of the transverse axis and applied to the milling of a diagonal joint, and 
     FIGS. 11 a  and  11   b  presents a turnable milling unit comprised in the apparatus of the invention as a projection from the direction of the transverse axis, applied to the milling of a straight joint and a diagonal joint. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     FIG. 1 shows a wall frame of framework construction of variable height according to the invention. The wall frame comprises vertical members  1  of a length that varies according to the height of the wall frame, placed at a distance from each other determined by the required frame post spacing, sloping top stringers  2  and a bottom stringer  3 . At the window opening there are vertical members  9 , at the door opening vertical members  10 , with horizontal members  4  placed above these openings, with further vertical members  6 , placed centrally relative to the openings, above the horizontal members  4 . Placed below the window opening is yet another vertical member  7 . 
     In FIG. 2, the frame component  3  (bottom stringer) is provided with two notches N about 5 mm deep extending across the stringer in its widthways direction to allow the connection of other frame components e.g. about the mid portion of the component. The notches have sloping walls, reducing the notch width towards the bottom of the notch. The notches are intended e.g. for the joining of frame components for a window, in which case the distance between them corresponds to the distance between the window frame components. Moreover, the ends of the frame component may be provided with bevellings U tapering towards the end, so the ends of the component will fit into notches provided for joints in other timber components. 
     The frame component  3  is provided with an identifying code  30  printed on its surface e.g. on the notched side at the end of the timber component, giving the type and dimensions of the component. In FIG. 2, the code S1a/AJ2500 means the horizontal member placed below the window in section a of wall frame S1 (in this case, the wall frame consists of several sections), whose length is 2500 mm. The code may naturally be composed as desired, and it may also contain other information than that proposed above. In addition, the same component can be provided with the marking  31 &lt;WINDOW printed beside the window notch N to indicate a window notch (at the first end of the window) and another marking  32  END&gt; at the other window notch N (at the second end of the window). Moreover, the bottom of the notch N may be provided with a code  33  S1a/AT2400 identifying the member to be joined to the notch, thus giving precise information as to which member is to be attached to a particular notch. 
     FIGS. 3-5 and  6   b  present different joints LI in magnified view. FIG. 3 shows a rectangular joint DET.1 between the upper end of a vertical member  7  and a horizontal member  8 , FIG. 4 shows a joint DET.2 between the right-hand end of a horizontal member  4  and a vertical member  10  and FIG. 5 shows a joint between the bottom stringer  3  and the lower end of a vertical member  10 . A skewed joint, in which the members are not at right angles relative to each other, between a vertical member  8  or  1  and a top stringer  2  is presented in FIGS. 6 a  and  6   b.    
     FIGS. 7 a - 7   c  present a more detailed view of an example of a joint between two members  4  and  10 , the members being shown separately. The end of frame component  4  has been machined into the shape of a straight letter U, forming the male member of the joint LI. The end face PPU and the splayed side surfaces SPU can be turned relative to the centre axis  100  to form an skewed joint, yet so that the components  4  and  10  are always dimensioned in relation to the centre axis  100  so that the measurements remain unaltered regardless of the joint angle. The bottom surface PPN and splayed side surfaces SPN of the notch joint are machined in locations and at angles defined in the wall construction plan. Thus, the notch N may be either perpendicular to the plane of cross-section of the object or in some other angle. 
     The surfaces PPU and SPU of the male member U are joined to the surfaces PPN and SPN, respectively, of the female member so that the bottom surface PPU goes against the end surface PPN and the side surfaces SPU go against the side surfaces SPN. The various surfaces of the joint components guide the male members U into the correct location and position in the notches provided for them. The distance PP separating surface PPU of joint component U and surface PPN of the notch N from the rear surface AP of the member  10  remains unchanged regardless of the thickness P of the frame components, so the joint ensures that the wall will preserve its design height regardless of variations in material thickness. The components of the vertical frame are so disposed that the frame component surface AP will be at the end of the wall frame, thus ensuring that the wall frame will preserve its design length regardless of variations in material thickness. In addition, all the frame components can be fastened to each other by using a fixing element and/or fixing agent. 
     Using an apparatus as presented in FIG. 8, frame components according to the construction drawing for a building with a wooden frame can be produced. The dimensions of the wooden frame are defined on a computer  81  using e.g. CAD software, which defines the measurements of each member as well as the bevellings and notches to be made in each member. Based on these data, the machining line cuts all components and provides them with precise markings, bevellings and notches as necessary so as to make them ready for installation, taking the requirements of frame post spacing, insulation and panelling into account. 
     For each frame component, the software also determines an identifying code  30  consistent with the installation drawings, each timber component being given a part code defined on the basis of input data. The code specifies the component type, i.e. the nature of the component, the place in the building where the component is to go, and its dimensions. 
     The code is composed of e.g. four parts, such as S1a/AV 562. The first part S1 indicates the wall frame in the building to which the component belongs, and the letter a following it indicates the section of the wall frame in cases where the wall frame consists of several successive sections. The third part AV defines the component type with a two-letter abbreviation; for instance, frame post TT, top stringer YJ, bottom stringer AJ, horizontal beam AV for an opening, frame post TL with a notch, frame post AL with an aperture and a notch, frame post TA with an aperture. The last part gives the length dimension of the member. 
     Once each timber component has been assigned a code defining the type and possible notches, the software will output the code data via a cable to the logic control unit  82  of the machine tool section. The logic control unit is also supplied with data specifying the measurements of each component as well as the bevellings and notches to be made in them. 
     The control unit  82  is mounted on the frame of the machine tool section of the apparatus, said frame consisting of frame beams  82 . The timber is conveyed by a roller conveyor  84  through the machine tool section. Also mounted on the frame are the following parts, listed in order starting from the raw material supply end: first milling unit  85 , first printer unit  86 , second milling unit  87  and cutting/milling unit  88 , the operation of which is described below in more detail. 
     The first milling unit  85  cuts in the frame component, which in the case of a wooden building frame  200  typically is a piece of planed wood material having a width of 200 mm and a thickness of 50 mm, two notches N about 5 mm deep, having bevelled sides and extending widthways across the timber component. The notches are intended for the joining of e.g. window frame components, in which case the distance between them corresponds to the distance between the window frame components. 
     The printer unit  86  may consist of e.g. an ink jet printer, which prints an alphanumeric identifying code  30  as described above, indicating component type and measurements, on one side of the frame component, at the end of the component, e.g. on the side with the notches. In addition, the same timber component may be provided with markings  31 - 33 . 
     The second milling unit  87  carries out the milling operations for the larger notches to be made e.g. in the narrow edge of the frame component, such as the notch for a frame beam, to be cut at the end or middle of the frame component. A marking defining such a component is correspondingly made on the surface of the component. 
     The cutting/milling unit  88 , which is provided with a saw blade, cuts the frame component to size. Moreover, it has milling cutters for the cutting of bevellings at the ends of the frame components, so that the ends will fit into notches provided in other components. The whole cutting/milling unit  88  is fitted on a swivelling frame  89  which can be turned about a transverse swing axis  90  to allow cuts to be made for skewed joints. The axis is located at the height of the centre line  100  of the timber component relative to the base  84 . Thus, the dimensioning in relation to the centre line  100  of the component remains unchanged regardless of the angular position of the cutting/milling unit  88  and the corresponding obliquity of the joint. 
     FIGS. 9 a ,  9   b ,  10 ,  11   a  and  11   b  present more detailed illustrations of the cutting/milling unit  88 . On the upper side, the unit comprises a rotating cutter combination  91  having a saw blade  92  in the middle for the cutting of the timber component and milling cutters  93  of a smaller diameter on either side of it for the making of bevellings. On the lower side there is only a milling cutter  94  for the making of bevellings on the opposite side of the frame components (FIGS. 9 a ,  11   a ). The upper combination  91  and the lower cutter  94  rotate on axles  95 ,  96 . FIG. 9 b  presents the cutter assemblies in front view. It shows that they are not exactly aligned one over the other, but their drive shafts  95  and  96  have a small distance between them in the sideways direction. With this arrangement, the saw blade  92  can cut deep enough to sever the timber component without touching the lower milling cutter  94 . In the case of a skewed joint, the cutting/milling unit  88  is turned with respect to the axis  90 , in which case the saw blade will cut in an oblique direction as shown in FIG. 10,  11   b , and the bevellings are made in accordance with this oblique cut because the whole unit  88  turns through the same angle about the same axis. Such a unit  88 , which has milling cutters on either side of a saw blade for the milling of the bevellings, makes it possible to produce several frame components from the same piece of wood because bevellings are made at each sawing end of the component in conjunction with the cutting. 
     It is obvious to the person skilled in the art that different embodiments of the invention are not restricted to the examples presented above, but that they may be varied within the claims presented below.