Joint for the angular connection of hollow profile members and method using such joint
10619405 ยท 2020-04-14
Inventors
Cpc classification
International classification
E06B3/972
FIXED CONSTRUCTIONS
E06B3/98
FIXED CONSTRUCTIONS
Abstract
Joint for the angular connection of a pair of hollow profile members (50) having an angular configuration corresponding to the angle of the assembled profile members (50) and comprising a slide base portion (2, 2, 2), a sheet metal portion (1, 1) superimposed thereupon and a bolt (5) passing through the sheet metal portion (1, 1) and screwed into a nut (4) mounted onto the base portion (2, 2, 2), wherein tightening of bolt (5) pushes upwardly extending surfaces on either side of portion (1, 1) whereby their sharp edges indent the walls of the hollow profile members being connected. The indentation and efficient angular connection of the hollow profile members is enhanced through: a) forming of the sharp edges of the sheet metal to align an aberrant edge thereof in an indentation appropriate direction, b) appropriately orienting the sheet metal portion (1, 1) to comply with a set of predetermined geometrical parameters and c) selectively employing varying embodiments of the slide base portion to obtain rapprochement of the points of indentation of the walls being indented.
Claims
1. A joint for angular connection of hollow profile members (50) to form door/window profile frames, wherein edges of the hollow profile members (50) are cut at an angle to obtain a matching contact following assembly thereof along a plane of symmetry (xx) passing through a plane of matching contact of the cut edges of said hollow profile members (50), the joint comprising: a slide base portion (2, 2, 2) having an angular configuration corresponding to an angle formed between a pair of connected hollow profile members (50), with an upper first base (20) with a centrally located cavity (20a) and with first side parts symmetrically extending on either side of said upper first base (20), each of said first side parts comprising a first section (21) extending into a second upwardly sloped section (22), each of said first side parts having outer planar surfaces (24, 25) configured to slidably contact a wall of each of a pair of chambers (53a, 53b) of the hollow profile members (50); a sheet metal mobile portion (1, 1) having an upper second base (10) with a centrally located through hole (10a) and second side parts symmetrically extending on either side of said upper second base (10), each of said second side parts comprising a first planar side surface (11) extending into an inwardly bent second planar side surface (12), said first planar side surface (11) with a length equivalent to a length of said first section (21) and said inwardly bent planar side surface (12) with a length generally equivalent to a length of said second upwardly sloped section (22) of said slide base portion (2, 2, 2), said second side surface (12) extending into an upwardly bent terminal side surface (13) oriented in a direction parallel to the plane of symmetry (xx) and terminating at sharp edges (16), said sharp edges (16) adapted to produce an indentation effect into walls of chambers (53a, 53b), said sheet metal mobile portion (1, 1) superimposed onto said slide base portion (2, 2, 2) so that said second base (10) is oriented parallel above said underlying first base (20), said first and second side parts symmetrically arranged on either side of the plane of symmetry (xx) passing through the plane of matching contact of the cut edges of said hollow profile members (50), and a bolt and nut assembly comprising a nut (4) fitted within said centrally located cavity (20a) of said slide base portion (2, 2, 2) and a bolt (5) adapted to pass through a hole (51a,b) of the hollow profile members (50) lying at said plane of symmetry (xx) and through said through hole (10a) of said sheet metal mobile portion (1, 1) and fastenable to said nut (4) to exert an upwardly pushing force onto said sheet metal mobile portion (1, 1) initiating sliding of said second side surfaces (12) thereof onto said second section (22) of said slide base portion (2, 2, 2) and lifting of said sheet metal mobile portion (1, 1) until said sharp edges (16) thereof indent the walls of chambers (53a, 53b) of the connected hollow profile members (50), wherein said second section (22) of said slide base portion (2, 2, 2) extends into an upwardly bent terminal side surface (23) oriented in a direction parallel to the plane of symmetry (xx), said second section (22) and said upwardly bent terminal side surface (23) defining a socket (22-23), said second side surface (12) and upwardly bent terminal side surface (13) on either side of said mobile portion (1, 1) nested within said socket (22-23) on either side of said slide base portion (2, 2, 2); each one of said sharp edges (16) of said sheet metal mobile portion (1, 1) comprising an edge (16c) adapted to contact and produce an indentation effect into the walls of chambers (53a, 53b), said edge (16c) formed through alignment in the longitudinal direction of said mobile portion (1, 1) of an aberrant sharp edge (16a) resulting from a cutting blade driven perpendicularly into a web of the sheet metal used in the manufacture of said sheet metal mobile portion (1, 1); said sheet metal mobile portion (1, 1) having a structure that complies with a set of geometrical parameters: an angle (a) formed by each of said upwardly bent terminal side surfaces (13) of the sheet metal mobile portion (1, 1) with a corresponding wall of each of the pair of chambers (53a, 53b) of the hollow profile members (50) whereupon said slide base portion (2, 2, 2) is mounted, and having a minimum value of 45; an angle (b) measuring 60 and formed by an inner wall of each one of the pair of chambers (53a, 53b) of the hollow profile members (50) whereupon said slide base portion (2, 2, 2) is mounted, and having a straight line passing through a terminal point (E1) of contact of the inwardly bent said second side surface (12) of the sheet metal mobile portion (1, 1) with said second section (22) of said base portion (2, 2, 2) and through a terminal point (E2) of impact of said sharp edge (16) of said sheet metal mobile portion (1, 1) respectively onto the opposing wall of chambers (53a, 53b) of the connected hollow profile members (50), and an angle (c) formed by a wall of chambers (53a, 53b) of the hollow profile members (50) indented by the sheet metal mobile portion (1, 1) with a line transversally crossing said sharp edge (16) of the sheet metal mobile portion (1, 1), and having a value with a range of 45-55.
2. The joint according to claim 1, wherein said sheet metal mobile portion (1, 1) is a sheet metal mobile portion (1) comprising the linear upwardly bent terminal side surfaces (13), said sheet metal mobile portion (1) used in the connection of hollow profile members (50) with chambers (53a, 53b) having a width with a range of 10-12 mm.
3. The joint according to claim 1, wherein said sheet metal mobile portion (1, 1) comprises the linear upwardly bent terminal side surfaces (13), each of said upwardly bent terminal side surfaces (13) extending at a zigzag extension (14-15) adapted to shift a line of impact and indentation of the sheet metal mobile portion (1) in a direction away from the plane of symmetry (xx), said zigzag extension (14-15) comprising a first segment (14) provided past a first bending point located at the end of said upwardly extending terminal side surface (23) of said slide base portion (2, 2, 2), said first segment (14) bent outwardly through a predetermined arc in a direction away from the plane of symmetry (xx) and a second segment (15) provided past a second bending point located at the end of the outwardly bent said first segment (14), said second segment (15) bent inwardly through an equivalent said predetermined arc in a direction of rapprochement of the plane of symmetry (xx), said sheet metal mobile portion (1) used in the connection of hollow profile members (50) with chambers (53a, 53b) having a width with a range of 13-25 mm.
4. The joint according to claim 1, wherein said slide base portion (2, 2, 2) comprises said upper first base (20) configured in an obtuse angle and said sheet metal mobile portion (1, 1) comprises said upper second base (10) configured in an analogous obtuse angle adapted to be mounted onto said upper first base (20) of said slide base portion (2, 2, 2), said outer planar surfaces (24, 25) forming an angle corresponding to the angle formed between the hollow profile members (50) brought in matching contact and adapted to slide in abutment with the walls of respective chambers (53a, 53b) of the connected hollow profile members (50), an indentation (45) provided at the vertex of said angle formed by the outer planar surfaces (24, 25), said indentation (45) adapted to avert an inconveniency in sliding contact of said outer planar surfaces (24, 25) abutting on the walls of the chambers 53a, 53b of the connected hollow profile members (50).
5. The joint according to claim 4, wherein said slide base portion (2, 2, 2) further comprises an additional base raising member (3) with an angular configuration identical to said angular configuration of said slide base portion (2), said additional base raising member (3) comprising a pair of intersecting sides with outer planar surfaces (34, 35) abutting on the walls of the chambers (53a, 53b) of the connected hollow profile members (50), a leg member (36) extending upwardly along the plane of symmetry (xx) from a line of intersection of said outer planar surfaces (34, 35), said leg member (36) having a top edge (30) configured in an oblique angle adapted to fit within said slight indentation (45) provided along the line of intersection of said outer planar surfaces (24, 25) of the base portion and leg members (37, 38) provided symmetrically on either side of said leg member (36), said leg members (37, 38) extending perpendicularly upwardly from said outer planar surfaces (34, 35) respectively and provided with a platform (32) extending at a curvilinear lateral edge (33) at the top thereof, said platform (32) and curvilinear lateral edge (33) thereof adapted to provide mounting thereupon of said sockets (22-23) provided on either side of the base portion (2).
6. The joint according to claim 1, wherein said slide base portion (2, 2, 2) has an angular configuration that corresponds to an angle formed between a pair of connected hollow profile members (50), with outer planar surfaces (24, 25) including said slight indentation (45) at a region of intersection thereof, an upper first base (20) with a centrally located cavity (20a) adapted to fixedly support said nut (4) and with sockets (22-23) symmetrically extending on either side of said first base (20) adapted to provide nesting of said second planar side surface (12) and of said upwardly bent terminal side surface (13) on either side of said mobile portion (1, 1), said slide base portion (2) further comprising a leg member (26) extending upwardly along the line of intersection of said outer planar surfaces (24, 25) and provided with said upper first base (20) at the top thereof and leg members (27, 28) provided symmetrically on either side of said leg member (26), said leg members (27, 28) extending perpendicularly upwardly from said outer planar surfaces (24, 25) respectively and provided with said sockets (22-23) at the top thereof.
7. The joint according to claim 6, further comprising an additional base raising member (3) with an angular configuration identical to said angular configuration of said slide base portion (2), said additional base raising member (3) comprising a pair of intersecting sides with outer planar surfaces (34, 35) abutting on the walls of the chambers (53a, 53b) of the connected hollow profile members (50), a leg member (36) extending upwardly along the plane of symmetry (xx) from a line of contact of said outer planar surfaces (34, 35), said leg member (36) having a top edge (30) configured in the shape of an oblique angle adapted to fit within said slight indentation (45) provided along the plane of intersection of said outer planar surfaces (24, 25) of said slide base portion (2) and leg members (37, 38) provided symmetrically on either side of said leg member (36), said leg members (37, 38) extending perpendicularly upwardly from said outer planar surfaces (34, 35) respectively and abutting on said outer planar surfaces (24, 25) of said slide base portion (2).
8. The joint according to claim 1, wherein said slide base portion (2, 2, 2) is a slide base portion (2) having an angular configuration that corresponds to an angle formed between a pair of connected hollow profile members (50), said slide base portion (2) comprising an upper first base (20) and sockets (22-23) symmetrically extending on either side of said first base (20) adapted to provide nesting of said second planar side surface (12) and upwardly bent terminal side surface (13) on either side of said mobile portion (1, 1) superimposed onto said slide base portion (2), said slide base portion (2) extending at side members (41, 42) adapted to fit within the chambers (53a, 53b) respectively of the connected hollow profile members, recesses (43, 44) respectively provided transversally along the surfaces of said side members (41, 42), said recesses (43, 44) adapted to receive strips of material of the walls of the chambers (53a, 53b) respectively cut through cutting blades applied exteriorly of the hollow profile members (50), said strips embedded within the recesses (43, 44) thereby enhancing stabilization of said side members (41, 42) within the chambers (53a, 53b) of the connected hollow profile members (50) in addition to the indentation of said sharp edges of the sheet metal mobile portion (1, 1) into the walls of chambers (53a, 53b).
9. The joint according to claim 1, wherein said hole (51a,b) of the hollow profile members (50) lies along said plane of symmetry (xx) and is adapted to receive a key (51) used in a tightening process of said bolt (5) comprises a first half hole (51a) medially along a first edge of chamber (53a) and a second half hole (51b) medially along a second edge of chamber (53b).
10. A method for using the joint of claim 1 for the angular connection of hollow profile members (50) to form door/window profile frames, the method comprising: a. Cutting the edges of the hollow profile members (50) adapted to angularly connect at an angle having half a value of an intended angle of connection thereof, the plane of symmetry (xx) passing through the plane of matching contact of said connected hollow profile members (50), and drilling the hole (51a,b) comprising a first half hole (51a) located centrally along the edge of a chamber (53a) of a first one of the connected hollow profile members (50) and a second half hole (51b) located centrally along the edge of a chamber (53b) of a second one of the connected hollow profile members (50), wherein said hole (51a,b) is adapted to receiving a key (51) used for tightening the bolt (5) provided along said plane of symmetry (xx); b. Selecting a slide base portion (2) or (2) with or without an additional base raising member (3) appropriately corresponding to the width of the chambers (53a, 53b) of the connected hollow profile members or a base portion (2) in combination with a sheet metal portion (1) or (11 and performing assembly of the joint through driving of the bolt (5) through the through hole (10a) of the sheet metal portion (1) or (1) and screwing the same into the nut (4) mounted onto the slide base portion; c. Introducing a first half of the assembled joint into the chamber (53a) of the first one of the connected hollow profile members (50); d. Bringing the chamber (53b) of the second one of the connected hollow profile members (50) into matching contact with chamber (53a) of the first one of the connected hollow profile members (50) and inserting a second half of the assembled joint that projects outwardly from chamber (53a) into the chamber (53b), whereby a matching contact of said first and second connected hollow profile members (50) is obtained and the hole (51a,b) is formed through abutment of matching half holes (51a) and (51b); e. Inserting the key (51) through the hole (51a,b) and rotation thereof for screwing the bolt (5) into the nut (4) until said upwardly bent parts (13) of the sheet metal mobile portion (1) or upwardly bent parts (13-14-15) of the sheet metal portion (1) impact and indent the walls of chambers (53a, 53b) thereby providing a firm connection of the connected hollow profile members (50) and alignment of the joint due to its symmetrical arrangement on either side of the plane of symmetry (xx).
Description
BRIEF DESCRIPTION OF THE DRAWINGS
(1) The invention will be made apparent to those skilled in the art by reference to the accompanying drawings, wherein:
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DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
(15) The joint of the invention relates to the angular connection of aluminium profiles without being limited thereto, as it may also be used in the connection of profile members made from other soft metals or plastics. In most circumstances, the hollow profile members to be connected are perpendicularly oriented and their ends are cut at 45 so as to obtain an aesthetically optimal matching contact and connection thereof. The drawings depict connection of perpendicularly oriented hollow profile members, without however excluding the possibility of connection at any other obtuse or acute angular orientation. Thus the joint of the invention is particularly proposed for the connection of hollow profile members used in the construction of door and window frames, such frames being adapted to house a glass or a shutter panel or an insect repellent textile surface, etc. The joint of the invention may however also be used in the connection of hollow profile members adapted to form partition panels, racking structures, railings, frames for pictures and paintings, furniture assemblies and other varying applications as appropriate. With the inventive features of the present invention, the proposed joint is appropriately adjusted for the connection of hollow profile members irrespective of the size of the receiving chambers thereof. An illustrative embodiment of such a hollow profile member 50 is presented in
(16) The joint of the present invention as shown in the exploded view of
(17) The sheet metal mobile portion 1, comprises side parts symmetrically extending on either side of a base 10, wherein each one of these side parts comprises a first planar side surface 11 extending into an inwardly bent second planar side surface 12 that eventually extends to an upwardly bent terminal side surface 13, such upwardly bent terminal side surfaces 13 having sharpened edges being adapted to indent the walls in the chambers 53a, 53b of the hollow profile members 50 being connected. The upwardly bent terminal side surfaces 13 have a straight line configuration in a first embodiment of a sheet metal mobile portion 1 shown in
(18) A bolt 5 is employed in providing interconnection of the elements of the joint of the invention, the bolt 5 having a bore and a threading such that it may be screwed using an Allen key 51, which as shown in
(19) With a scope of achieving an optimal indentation effect of the walls of chambers 53a, 53b of the hollow profile members 50 being connected and taking into account that these chambers may have a variable width, the sheet metal mobile portion 1 with the linearly configured upwardly bent terminal side surfaces 13 of the first embodiment is preferably used with chambers 53a, 53b having a width within a range of up to about 10-12 mm and the sheet metal mobile portion 1 with the zigzag extension 14, 15 of the second embodiment is preferably used with chambers 53a, 53b having a larger width that reaches up to about 25 mm, thereby advantageously displacing the line of indentation of the walls of chambers 53a, 53b by the sharpened edge of the upwardly bent parts of the sheet metal mobile portion in a direction away from the plane of symmetry xx at a distance increased in comparison with the distance of elongate upwardly bent terminal side surfaces 13 with a straight line configuration. The zigzag extension 14, 15 of the aforementioned second embodiment serves to provide an optimally effective indentation effect in hollow profile members comprising chambers 53a, 53b having a larger width that reaches up to about 25 mm.
(20) Alternatively or in addition to selective use of either the sheet metal mobile portion 1 or 1 in order to achieve an optimal line of impact and indentation onto the walls of chambers 53a, 53b, varying embodiments of the base portion 2, 2, 2 might be employed, such alternative embodiments being described hereinafter.
(21) As mentioned hereinabove the sheet metal mobile portion 1, 1 comprises an upper base 10 that is being disposed onto an underlying upper base 20 of the base portion 2. In accordance with a preferred embodiment of the invention, the upper base 10 and the upper base 20 are configured as obtuse angles with the vertex of these angles passing through the plane of symmetry xx of the joint of the invention.
(22) According to a first embodiment of the invention the sheet metal mobile portion 1, 1 is provided with side parts symmetrically arranged on either side of the base 10 and each one of these side parts comprises a first planar side surface 11 extending into an inwardly bent second planar side surface 12, wherein the abovementioned first planar side surface 11 has a length generally equivalent to the length of an underlying corresponding first section 21 and the inwardly bent planar side surface 12 abuts onto a correspondingly sized upwardly sloped section 22 of base portion 2 and has a length generally equivalent to the length of this underlying corresponding upwardly sloped section 22 of the slide base portion 2, 2, 2, such upwardly sloped sections 22 being adapted to provide, when bolt 5 is being tightened, a sliding platform for the inwardly bent flat surfaces 12, this sliding leading to the sheet metal mobile portion 1, 1 being lifted and thereby being brought at a position enabling indentation of the walls of the chambers 53a, 53b of the hollow profile members being connected. The inwardly bent planar side surfaces 12 of the sheet metal mobile portion 1, 1 are bent upwardly through an arc of 180, thereby forming the upwardly bent terminal side surfaces 13, which are oriented in a direction parallel to the plane of symmetry xx. Accordingly, the aforementioned upwardly sloped sections 22 of base portion 2 are also bent upwardly through an arc of 180, thereby forming terminal side surfaces 23, which are oriented in a direction parallel to the plane of symmetry xx, such terminal side surfaces 23 in combination with the upwardly sloped sections 22 thereby defining sockets 22-23 adapted to receive the correspondingly inwardly bent planar side surfaces 12 followed by the upwardly bent terminal side surfaces 13 of the sheet metal mobile portion 1, 1.
(23) According to the second embodiment of the invention wherein the sheet metal mobile portion 1 is employed to serve connecting of larger profile chambers 53a, 53b having a width within a range of 13-25 mm, the upwardly bent terminal side surfaces 13 extend into zigzag extensions 14-15, such zigzag extensions 14-15 being adapted to shift the line of impact and indentation of the sheet metal mobile portion 1 in a direction away from the plane of symmetry xx of the joint of the invention. In the case of the sheet metal mobile portion the intended zigzag extension 14-15 is implemented with a pair of bending points along the upwardly bent parts of the mobile portion 1, a first bending point being provided at the end of the aforementioned upwardly extending terminal side surfaces 23 of base portion 2, whilst a first portion 14 of the zigzag extension 14-15 is bent outwardly through a predetermined arc in a direction away from the plane of symmetry xx and a second bending point being provided at the end of the outwardly bent first portion 14, whereby a second portion 15 of the zigzag extension 14, 15 is being bent inwardly through the same aforementioned predetermined arc in a direction of rapprochement of the plane of symmetry xx. It is therefore clear that in this second embodiment of the invention the upwardly bent side of the sheet metal mobile portion 1 consists of three successive linear segments, i.e. a first linear segment 13 that is encased within the socket formed in between the upwardly extending terminal side surface 23 and the upwardly sloped section 22 of base portion 2, a second linear segment 14 extending between the aforementioned first and second bending points and a third linear segment 15 downstream of the second bending point, the latter inwardly bent linear segment 15 achieving displacement of the line of impact onto the wall of the chamber of the hollow profile member 50 in a position that ensures an optimal indentation thereof.
(24) It is a requirement of the joint of the invention to provide the sheet metal mobile portion 1, 1 made from a relatively hard metal, such as steel or other, so that it may have the capacity of indentation of the walls of the profile members 50 being connected, the latter being made from a relatively softer material, such as aluminium or plastic or other.
(25) The fixedly mounted slide base portion 2 as shown in
(26) With the configuration described hereinabove a certain desirable necessary length of contact of the firmly mounted base portion 2 with the overlying sheet metal mobile portion 1, 1 is ensured such length of contact providing an appropriate slide guide for the mobile portion 1, 1.
(27) The aforementioned upwardly bent terminal parts 13 of the sheet metal mobile portion 1 or 13-14-15 of the sheet metal mobile portion 1 respectively have a length such that, as shown in
(28) As characteristically shown in the enlarged detail view of
(29) As illustrated in
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(31) Alternatively or in addition to the raised slide base portion 2 described hereinabove that is appropriately applicable in the connection of hollow profile members 50 with chambers 53a, 53b of a larger width, the standard slide base portion 2 might be employed to serve connection of such profile members by means of lifting it at the desired height through using an additional base raising member 3, which, as illustrated in
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(34) In
(35) It is therefore made evident that the angular connection of varying sizes of hollow profile members necessitates using an appropriate base portion 2 or 2 or 2 in combination with an appropriate sheet metal mobile portion 1 or 1 in order to implement an optimally reliable angular connection of the hollow profile members with the joint of the invention satisfying certain predetermined geometrical parameters as enlisted hereinbelow: The angle (a) formed by each one of the upwardly bent terminal side surfaces 13 of the sheet metal mobile portion 1, 1 with a corresponding one of the outer planar surfaces 24, 25 of the base portion 2, 2, 2 with a wall of each one of the chambers 53a, 53b of the hollow profile members 50 whereupon the base portion 2, 2, 2 is mounted has a minimum value of 45 (
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(37) As mentioned in the introductory part hereinabove, an object of the present invention is to carry out an appropriate forming of the aberrant terminal edge of the sheet metal portion of the joint of the invention after cutting thereof with a scope of aligning it in the longitudinal direction of the planar sheet metal and of creating a sharpened edge thereof as appropriate for impacting and indenting the wall of the chambers of the hollow profile members being connected.
(38) As illustrated in
(39) It is herein noted that the aligned configuration of the terminal edge of the sheet metal portion is not visible to a naked eye, but it is observed as a change in the texture of the surface of the sheet metal portion 1 or 1.
(40) The use of the joint of the invention specifies an innovative method of angular connection of a pair of abutting hollow profile members made from aluminium and related materials, the method comprising the following steps:
(41) a. Cutting the edges of the hollow profile members 50 adapted to being angularly connected, such cutting being made at an angle having half the value of the intended angle of connection of hollow profile members 50, e.g. for an intended connection of hollow profile members at an angle of 90, profile edges are cut at an angle of 45, and drilling of a hole 51a,b allowing driving of the key 51 used for tightening the bolt 5, wherein one half 51a of hole 51a,b is located centrally along the edge of chamber 53a of a first one of the hollow profile members 50 being connected and another half 51b of hole 51a,b is located centrally along the edge of chamber 53b of a second one of the hollow profile members 50 being connected.
(42) b. Selecting a base portion 2 or 2 of the joint of the invention with or without an additional base raising member 3 appropriately corresponding to the width of the chambers (53a, 53b) of the hollow profile members being connected or of a base portion 2 in combination with a sheet metal portion 1 or 1 and performing assembly of the joint through driving of the bolt 5 through the through hole 10a of the sheet metal portion 1 or 1 and screwing the same into the nut 4 mounted onto the base portion.
(43) c. Introduction of a first half of the assembled joint into the chamber 53a of a first one of the hollow profile members 50 being connected.
(44) d. Bringing chamber 53b of a second one of the hollow profile members 50 being connected into matching contact with chamber 53a of the first one of the hollow profile members 50 being connected and inserting the second half of the assembled joint that projects outwardly from chamber 53a into the chamber 53b, whereby hole 51a,b is being formed through the abutment of matching half holes 51a and 51b.
(45) e. Inserting the key 51 through the hole 51a,b and rotation thereof for screwing bolt 5 into the nut 4 until said upwardly bent parts 13 of the sheet metal portion 1 or 13-14-15 of the sheet metal portion 1 impact and indent the walls of chambers 53a, 53b thereby resulting at a firm connection of the hollow profile members 50 and alignment of the joint due to its symmetrical arrangement on either side of the plane of symmetry xx.