Abstract:
A frame piece for a rack of a switching cabinet having fastening possibilities, torsional rigidity, material expenditure and manufacture that corresponds to requirements. The frame piece includes a section outside as a connection section between outsides of the rack that contact at right angles. Fastening sections of a section inside are connected to the connection section, which have in a longitudinal direction of the section fastening mounts and transition into section sides having second fastening mounts. The fastening sections are at a first angle to the outsides of the rack and the section sides are at a second angle to the connected fastening section. The fastening sections and the section sides form two inside edges of the section inside.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to a rack for a switching cabinet. 
     2. Description of Prior Art 
     A wide variety of requirements are imposed on a rack of a switching cabinet, all of which must be met by the cross-sectional shape of the employed frame pieces. Frame pieces that deviate in cross-sectional shape of the vertical frame piece can be used in the region of the lower or upper frame. A wide variety of fastening possibilities aligned in several directions are required precisely in the vertically aligned frame pieces of the rack. Optimal strength, preferably torsional rigidity must also be achieved with the least possible material cost for the frame pieces and simple manufacture of the frame piece must nevertheless be possible. Also, in the region of the vertical outside corner edges of the rack sufficient free space must be present to mount the hinge flap of a cabinet door and to form and accommodate sealing elements for the side walls or cabinet back wall being mounted. 
     A number of frame pieces are known for the rack of a switching cabinet that partly meet the mentioned requirements, but do not offer a satisfactory solution in all respects. Frame pieces designed as open hollow sections perform much more poorly than closed hollow sections. 
     SUMMARY OF THE INVENTION 
     It is one object of this invention to provide a frame piece for a rack of a switching cabinet, which has sufficiently high strength for universal fastening possibilities with limited material cost and simple manufacturing, particularly when used as a vertical frame piece and optimally meets the imposed requirements. 
     This object is solved according to this invention with a frame piece having a section outside as a connection section between the outsides of the rack that meet each other at right angles. The fastening sections of a section interior are connected to the connection section, which have fastening mounts in the section longitudinal direction and also grade into section sides having fastening mounts. The fastening sections are situated in a first angle to the outsides of the rack and the section sides are positioned at a second angle to the fastening section being connected. The fastening sections and section sides form two inside edges of the section interior. 
     The section outer parts designed as a connection section starting from the outsides of the rack that contact each other at right angles leave sufficient free space in the region of the outer corner edge to meet the requirements for attachment of a cabinet door and for sealing of the side walls, back wall or cabinet door being mounted. 
     The fastening sections in the section sides of the section internal side have different fastening planes in different directions, in which their alignment with respect to the outsides of the rack can be established with choice of the first and second angles. The torsional rigidity of the frame piece can be optimized and the material expenditure reduced with choice of these angles. Also, the section sides facing each other form a mount opened toward the interior of the rack for attachment of assembly rails, which can expand the variation in fastening possibilities. 
     The fastening possibilities can be improved because the fastening mounts of the fastening sections have a first identical spacing to the inner edges, and the fastening mounts of the section sides have a second identical spacing to the inside edges. 
     If the embodiment is simplified so that the first spacings are chosen equal to the second spacings, then uniformly configured assembly rails, attachment parts and the like can be mounted on all fastening planes of the fastening sections and section sides. 
     The torsional rigidity of the frame piece can be increased by joining the section sides to each other and/or to the connection section. 
     Incorporation in a rack can be simplified by designing the frame piece as having mirror-image symmetry with respect to the corresponding rack diagonal. 
     The first and second angles can be chosen as acute, right or obtuse angles so that the fastening planes can be positioned in different directions. 
     In order to configure the frame piece as a closed hollow section, in one embodiment the section sides are connected to each other directly or via a transition section. 
     Greater capabilities for selecting the angle between the outside of the rack and the fastening sections and the angle between the section sides and the fastening sections is then allowed with the transition section or direct connection of the section sides to the connection section of the section outer part. 
     The transition section between the section sides runs parallel to the facing part of the connection section and can be connected to the facing part. 
     The fastening mounts can be designed as holes and/or square or rectangular openings and extend as rows with uniform spacing in a longitudinal direction of the section. The fastening mounts in the fastening sections and section sides can then differ in design and/or spacing from those in the section sides. 
     According to one embodiment the alignment of the fastening planes can be laid out so that the fastening sections each run parallel to the section sides not contacted. 
     If the section internal side has a transition section between the section sides, then for more fastening possibilities, the transition section can have fastening mounts. 
     The frame piece can be simply produced as a part of an extruded section. 
     In another manufacturing possibility for the frame piece it is formed as a stamped-bent part, which is preferably joined in the region of the free edges of the section sides or is formed as a stamped-bent part joined in the region of the connection section. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     This invention is further explained with reference to eight practical embodiments of frame pieces shown in the drawings in cross sections as shown in FIGS. 1 to  8 . 
    
    
     DESCRIPTION OF PREFERRED EMBODIMENTS 
     In all practical examples AS 1  and AS 2  denote two outsides of a rack that contact at right angles, whose rack diagonal RGD is drawn as a bisecting line. The two outsides AS 1  and AS 2  form an outer comer edge AEK which is not adversely affected, however, by the frame piece with the section outside. The section outside is denoted as connection section  11 , which starts from the two outsides AS 1  and AS 2  and toward the outer corner edge AEK leaves a sufficiently large free space FR for attachment of a cabinet door and sealing and for introduction of the covering elements that contact here, such as side walls, a back wall, and a cabinet door. The connection section  11  can also be configured differently, but always leaves a free space FR for the outer corner edge AEK. 
     In the practical example according to FIG. 1 the ends of the connection section  11  in the region of outsides AS 1  and AS 2  transition into fastening sections  12  and  14 , which have in the longitudinal direction of the section rows of fastening mounts  13  and  15  and are at an acute angle α to the facing outsides AS 1  and AS 2 . Section sides  16  and  18  are connected to the fastening sections  12  and  14 , which also have rows of fastening mounts  17  and  19 . The fastening sections  12  and  14  and the section sides  16  and  18  form two inside edges IK 1  and IK 2 . The fastening mounts  13  and  15  of the fastening sections  12  and  14  have a first spacing A 1  from the inside edges IK 1  and IK 2 , whereas the fastening mounts  17  and  19  of section strips  16  and  18  have a second spacing A 2  from the inside edges IK 1  and IK 2 . The spacing A 1 , however, can also be chosen equal to the spacing A 2 . The section sides  16  and  18  enclose an acute angle β with the connected fastening sections  12  and  14 . The edges of section sides  16  and  18  facing away from fastening sections  12  and  14  are connected via a transition section  20 . The transition section  20  can run parallel to the facing part of the connection section  11  of the section outside and be rigidly connected to the facing part. The transition section  20  can also run at a spacing parallel to the facing part of connection section  11 . In a frame piece of this type produced as a stamped-bent part, the transition section  20  can comprise two overlapping end sections, which are connected to section sides  16  and  18 . The contact and joining site can also be situated in the region of connection section  11 . The fastening mounts  13  and  15  of the fastening sections  12  and  14  can be designed the same and aligned like the fastening mounts  17  and  19  of the section sides  16  and  18 . However, the fastening mounts  13  and  15  can also differ in design, alignment and spacing. The angle α can be chosen the same as angle β. 
     In the frame pieces according to FIG. 2 the angles α and β differ significantly from the practical example according to FIG. 1, since the section sides  16  and  18  are in direct contact and are joined in the center to connection section  11 . The frame piece according to FIG. 2 is also designed as having mirror-image symmetry with respect to the rack diagonal RGD. The spacings of the fastening mounts  13  and  17  from the inside edge IK 1  correspond to the spacings of the fastening mounts  15  and  19  from the inside edge IK 2 . By shortening the connection section  11 , the free space FR to the outer corner edge AEK can be reduced. The fastening sections  12  and  14  can be the same width as the section side  16  and  18  and half as wide as the connection section  11  so that the two cavities of the frame piece form isosceles or equilateral triangles. 
     As shown with reference to the practical example according to FIG. 3, the section sides  16  and  18  can also be directly connected to one another at a spacing from connection section  11 . In a frame piece starting as a stamped-bent part of this type it is recommended that the contact and joining site be positioned in the region of the connection section  11 . The angle α can be chosen as an acute angle and angle β as an obtuse angle. The spacings A 1  and A 2  of the fastening mounts from the inside edges IK 1  and IK 2  are different. 
     In the practical example according to FIG. 4 the fastening sections  12  and  14  are perpendicular to the facing outsides AS 1  and AS 2  and the section sides  16  and  18  are perpendicular to the fastening sections  12  and  14 , for example, α=β=90°. It is recommended that the spacings of the fastening mounts  13 ,  15 ,  17  and  19  to the corresponding inside edge IK 1  and IK 2  be chosen equally large. The section sides  16  and  18  can then be directly connected to each other or via the transition section  20  and/or connected to the connection section  11 . The section outside can have a support section  21  which lies against the facing outside AS 2  and assumes the transition from connection section  11  of the section outside to the fastening section  14  of the section inside. 
     In the practical example according to FIG. 5 both ends of the connection section  11  grade into the fastening sections  14  and  12  of the section inside via support sections  21  and  22 . The fastening sections  12  and  14  are perpendicular to the support sections  22  and  21 , for example, α=90°. The section sides  16  and  18  are connected at an acute angle β to the fastening sections  12  and  14  and are directly connected to the connection section  11 . The fastening mounts  13 ,  15 ,  17  and  19  have the same spacing from the corresponding inside edge IK 1  or IK 2 . 
     In the frame pieces according to FIG. 6 the section sides  16  and  18  are perpendicular to the fastening sections  12  and  14  being connected, for example, α=β=90°. The section sides  16  and  18  are connected to each other via the transition section  20 , which runs at a spacing parallel to connection section  11  and can have additional fastening mounts  23 . The widths of the fastening sections  12  and  14 , as well as the section sides  16  and  18 , can also be chosen equally large and the support connectors  21  and  22  can be dimensioned so that the transition section  20  or the section sides  16  and  18  can be directly connected to the connection section  11 . 
     FIG. 7 shows a frame piece in which the angles α and β are obtuse. The support sections  21  and  22  are adjusted so that the connected section sides  16  and  18  are at least supported on the connection section  11  or can be connected to it. The connection section  11  can be joined and overlapped in the region of the support or connection site. 
     As shown in FIG. 8, the connection section  11  need not run linearly and can also be designed step-like or run in any desired manner from the support sections  21  and  22 , as long as there is sufficient free space FR to the outside corner edge AEK. The fastening sections  12  and  14  are at an acute angle α to the outsides AS 1  and AS 2  and the sections sides  16  and  18  are connected at an acute angle β to the fastening sections  12  and  14 . The section sides  16  and  18  are perpendicular to each other and run parallel to their corresponding outsides AS 1  and AS 2 . The section sides  16  and  18  meet in the region of the rack diagonal RGD on the corner of the step-like connection section  11  and can be rigidly connected to the connection section  11 . 
     As shown in FIG. 4, the cross section of the frame section both in the region of the section outside and in the region of the section inside need not necessarily be designed as having a mirror-image symmetry with respect to the rack diagonal RGD. Asymmetric designs arc also conceivable, when special requirements are imposed on the fastening possibilities and fastening directions.