Patent Publication Number: US-3874133-A

Title: Systems for interconnecting plates

Description:
United States Patent [1 1 Silvius [451 Apr. 1, 1975 [76] Inventor: Arthur Aurelius Xaverius Silvius,  
 Leerdamseweg 34, Asperen, Netherlands [22] Filed: June 9, 1972 [21] App]. No.: 261,426  
 [30] Foreign Application Priority Data June 10. 1971 Netherlands 7107973 [52] US. Cl. 52/758 ll), 52/285 [51] Int. Cl. F161) 5/06 [58] Field of Search 287/l89.36 D, 189.36 C  
 287/l89.35, 20.92 D, 20.92 C, 20.924; 1 46/29, 31; 52/285, 288  
 Primary Examiner-Werner ll-l. Schroeder Assistant Examiner-Wayne L. Shedd Attorney, Agent, or Firm-Sh.erman &amp; Shalloway [57] ABSTRACT A system for interconnecting plates, panels or the like to one another includes a plurality of interconnecting elements which are inserted into slots formed in the plates or panels and a main coupling with which the interconnecting elements are mated to join the plates or panels. Preferably, the interconnecting elements have flanges thereon, which engage opposite sides of the plates adjacent to the edges of the slots. The flanges are joined by web portions which extend therebetween. The main couplings have portions extending either therefrom or therein which slide into openings in the interconnecting elements which extend between the web portions. In order to achieve a snug fit between these projecting portions and the interconnecting elements, the projecting portions either dove-tail into the interconnecting elements, or engage with slots with ribs extending between the web portions of the interconnecting elements.  
 12 Claims, 27 Drawing Figures PATENTLL; 1 W5 saawzure PMENIEDAPR 11975 3,874,133  
 sum 5 [1F 6 PNEN MFR 1 I975 SHEET 6 OF 6 SYSTEMS FOR INTERCONNECTING PLATES BACKGROUND OF THE INVENTION This invention relates to a system for interconnecting a plurality of plates, panels or the like. More particularly. this invention relates to a system for interconnecting plates, panels or the like, wherein separate couplings are used to effect the interconnection.  
  For quickly and detachably interconnecting plates and boards a number of systems are known in the furniture industry. Such systems generally use a rotatable hook, mounted in a recess in the edge of one plate or board. which grips an eye or pin, in or on another plate or board. Such a system forms a good connections, but the mounting of the connecting components is rather complicated and expensive. Consequently, an object of this invention is to avoid these disadvantages and to accomplish a considerable simplication and reduction in costs.  
  To this end the system according to the invention uses two or more interconnected clamping pieces of which the crosssection has the shape of an I or a double dove-tail or a shape derived therefrom which is adapted to be clamped in a notch or plate to be connected.  
  The clamping pieces are preferably made from elastomeric material. However, they may be manufactured from stiff material, in which case the clamping force is effected by the elasticity of the connected plates.  
  In the case where a clamping piece has an I-shaped crosssection the web of the I may be pushed into a notch of a plate and both flanges will engage respectively opposite surfaces of the plate. Clamping can then be effected by the fact that the notch is slightly narrower than the web of the I and/or by the fact that the distance of the facing surfaces of the flanges is somewhat smaller than the thickness of the plate.  
  When. however. the crosssection ofa clamping piece has the shape of a double dove-tail, clamping will only be effected by the fact that the notch has approximately a similar shape. but is of somewhat smaller dimensions.  
  The invention has the advantage that the plates to be connected need only be provided with simple notches and that the interconnection of various plates can be realized without tools by simply pushing the clamping pieces into the notches of the various plates. It has appeared that the connection can be very solid by proper selection ofthe elasticity of the material and of the mutual proportion of the dimensions of the clamping pieces and notches.  
  A compact connecting element for interconnecting four plates contains four clamping pieces which are mutually arranged in the form of a cross.  
  When additionally at least one slot has been applied in the web of a clamping piece it will be possible to clamp a glass sheet or a similar sheet of hard material into this slot in a position perpendicular to the board into a notch of which that clamping piece has been applied.  
  Clamping of glass sheets into a slot of a rather stiff connecting element is described in the Dutch patent application No. 6.902.537 of applicant.  
  In this case the web of each of the clamping pieces comprises preferably two slots which are separated by a partition wall. In that case the I-shaped crosssection of a clamping piece will actually be H-shaped and the H-shape can be considered as being derived from the I-shape.  
  A slot can be applied in the web of each I or in the mentioned partition wall, which slot is intended for clamping receiving an adaptor with an I-shaped profile, which itself is adapted to clamp into a notch in a plate.  
  This combination of connecting elements and adaptors is suitable to be applied for various plate thicknesses and eventually also to various notch widths. A similar adaption to different plate thicknesses or notch widths can also be obtained if the facing surfaces of the two flanges of each I-shaped clamping piece or adaptor are stepped.  
  In some cases it may be advantageous to divide the element into two halves according to a central longitudinal plane, one of the halves being provided with at least one protruding pin on the web of each clamping piece, which pin fits in a hole of the other half.  
  If the clamping pieces define a central aperture in which can be received and clamped a separate filling piece, there is a possiblity to interconnect a number of boards and then to close the channel defined by the edges of the boards by means of the filling pieces. These filling pieces will also increase the strength of the connecting element and consequently also of the connection.  
 In the Dutch patent application No. 6,902,537 of applicant a stiff elastic disc is described provided with four slots mutually enclosing an angle of which are adapted to clamp thin hard sheets, such as glass sheets. The invention gives the possibility to use such a disc additionally for the connection of relative thick boards. so that thin window-panes and thick board can be interconnected.  
  To this end elastic parts are protruding on both sides of at least one of said slots which parts form the flanges of a clamping member with an I-shaped crosssection which can be clamped into a notch of a thicker board.  
  The possibility of application of the stiff elastic disc for the connection of relative thick boards will be optional if the elastic protruding parts are composed of two detachably interconnected halves and are applied in openings between the said slots of the connecting el&#39; ement.  
  The disc which is provided with elastic protruding parts can be adapted in a similar manner to the connection of boards of different thicknesses by providing each of the elastic protruding parts with a longitudinal slot parallel to the plane of the element for receiving a reducer.  
  It is within the scope of the invention to interconnect the clamping pieces of a connection element in a detachable manner. The advantage thereof may be that the separate clamping pieces can be manufactured in a simpler and less expensive way; it might also be desirable to clamp each of the clamping pieces into a notch of a board before they are interconnected. Furthermore the mutual detachable connection of the clamping pieces gives the possibility to choose the number of clamping pieces per connection element.  
  In the following the invention will be further explained referring to the FIGS., in which are shown various embodiments of connecting elements according to the invention.  
  FIG. 1 shows a perspective view of a connecting element with four clamping pieces arranged in the form of a cross and is a view of the boards to be connected by this element.  
  FIGS. 2a and 2b show respectively connecting elements with three and two clamping pieces with an I- shaped crosssection.  
  FIG. 3 shows a connecting element which is also appropriate for the connection of glass sheets.  
  FIGS. 4 to 13 inclusive show different possibilities of the shape of the clamping pieces of connecting elements.  
  FIGS. 14a to l4e inclusive show a connecting element according to the Dutch patent application No. 6,902,537 with additional accessories which can form together an I-shaped clamping piece.  
  FIGS. 15 and 16 are perspective views of additional embodiments of interconnecting systems in accordance with the present invention showing a pair of interconnecting elements joined by main couplers.  
  FIGS. 17 and 18 are perspective views of still another embodiment of interconnecting systems in accordance with the present invention showing main couplings which mate with interconnecting elements to join panel members.  
  FIG. 1 shows a connecting element 1, which is preferably manufactured from elastomer material, for interconnecting four boards 20 to 2d inclusive, which are each provided with a narrow notch 3. The connecting element comprises four webs 4 which are arranged crosswise and each of which being adapted to be pushed into a notch 3 ofa board. The webs are on both sides defined by flanges perpendicular to the pushing direction. These flanges form in FIG. 1 the corner pieces of a square but they are in FIG. 2 much smaller. In both cases the connecting element can be considered as a number of interconnecting clamping pieces 5-4-5 of which the crosssection perpendicular to the pushing direction are I-shaped. The clamping effect between clamping piece and board is realized by the fact that the web 4 is somewhat bigger than the width of the notch 3 and/or by the fact that the distance of the facing surfaces of the two flanges of each clamping piece is somewhat smaller than the thickness of the board. The four webs enclose in FIG. 2 a connection part 6 which has the same thickness as the flanges 5 but this part could also have in principle the same thickness as the webs 4 and can even be omitted in some cases or be realized in a detachable manner. It will be evident that no tools are needed for realizing the connection or for loosening the connection.  
  FIG. 2a shows the connection element with three clamping pieces and FIG. 2b a connecting element with two clamping pieces, all having an I-shaped crosssection.  
  FIG. 3 shows a connection element with clamping pieces which are arranged crosswise with respect to each other the web of each of these clamping pieces being provided with two slots 9, which are separated from each other by means ofa partition wall 11. Consequently the crosssection of each clamping piece is actually I-I-shaped, which shape can be considered as to be derived from the I-shape. As appears from the figure the web 4 of two clamping pieces is pushed into a notch 3 of a board 2b, 2d respectively. A glass sheet 12 can be clamped into the slot 9,10 of each web 4. In order to support the bottom edge of the glass sheet 12 a shallow narrow slot 13 has been applied in the board 2d (FIG. 3). This slot 13 could be omitted if a strip of a suitable length and width is cut from the bottom edge of the glass sheet.  
  FIGS. 4 and 7 show varieties of the connecting elements with clamping pieces with I-shaped crosssection according to FIGS. 1 and 2.  
  FIG. 5 shows a connection element with four clamping pieces which are arranged crosswise with respect to each other and which have a double dove-tailshaped crosssection. In this case no separate flanges are present, so that the clamping effects only can be realized in that the board to be connected is provided with a slot of similar shape which, however, has smaller dimensions. The connection can be compared with a double dove tail connection.  
  FIG. 6 shows a connection element which can be considered as to be a combination of FIG. 3 (each web has slots 9, 10 for engaging a glass sheet) and FIG. 5 (the shape of the web is a double dove-tail).  
  FIG. 8 shows a connection element which as such and in connection with a I-I-shaped adaptor 14, which has been previously pushed into a board notch, is suitable for different widths of the notches 3 and for different thicknesses of the boards 2. A slot 13 has been applied in the partition wall of the I-I-shaped adaptor into which is clamped the web 4 of a clamping piece of a connecting element. This situation is shown in crosssection in FIG. 8b. The facing surfaces of the flanges of the clamping pieces are stepped to make them usable for the notch widths and board thicknesses shown in FIGS. 86 and 8d.  
  FIGS. 9 and 10 show varieties of the connecting elements with the H-shaped clamping pieces according to FIG. 3. In FIG. 9 the slots in the web of the H are V- shaped.  
  FIG. 10 shows a connection element composed of two halves. The halves are interconnected by means of detachable pin-sleeve connections 17.  
 FIGS. 11, 12 are varieties of FIGS. 1,2.  
 FIG. 13 is a variety of FIG. 5.  
  It is noted that in FIGS. 10 to 13 inclusive the four clamping pieces which are arranged crosswise with respect to each other define a central aperture which can be closed by a detachable filling piece 16. This gives the possibility to interconnect a number, for example four, of boards, subsequently to fill the channel defined by the board edges which are turned to each other, by means of a lath and finally to apply the filling pieces into the respective connecting elements.  
  Referring now to FIGS. 14a, 14b, 14c, 14d and 14e, there is shown a system for connecting thin sheets, such as glass sheets (not shown) to relatively thick boards, designated generally by the numeral 102. The system includes a main coupling 103 which is in the form of a disc, such as that disclosed in the applicants Dutch patent application No. 6,902,537. The main coupling or disc 103 has four slots 105, which extend therein and are spaced apart from one another. The slots 105 receive the afore-mentioned thin sheets or glass panels (not shown).  
  In order to also connect the relatively thick panels or boards 102 shown in FIG. Me to the coupling means 103, it is necessary to utilize pairs of interconnecting elements, designated generally by the numeral 106 and shown in FIGS. 14c, 14b and 14c. Each interconnecting element has two halves 106a and 10619, which are disposed on opposite sides of the coupling element 103 and have generally triangular portions 107 thereon which fit into openings 108 disposed in the discs 103. The projecting portions 107 on the halves 106a and 106!) of the interconnecting elements have a thickness which is approximately one-half the thickness of the disc 103, so that the portions extend to abutt one another half-way through the openings 108 (see FIG. 148).  
  In order to securely mount the interconnecting elements 106 on the discs 103, the discs 103 have opposed projections 111 and 112, which extend into the opening 108 to define a substantially triangular configuration for positioning the projecting portions 107 (see FIGS. 14a in conjunction with FIG. 14b). The projections 111 and 112 prevent the interconnecting elements 106 from rotating relative to the discs 103. Each projecting portion 107 is a semi-circular shaped pin 113 which extends into a recess 114 on the opposite projection portion 107, when the two halves 106a and 10612 of the interconnecting means are snapped together (see FIG. 1412 in conjunction with FIG. 14c). Each half 106a and 106b of the interconnecting elements 106 has a hub 116 extending therefrom, which in turn registers with the opposite hub via a pin-inaperture arrangement 117-118. The hubs 116 are disposed to abutt outside of the periphery of the disc 103 when the interconnecting elements 106a and 10612 are snapped together on the hub 116. In order to facilitate snapping together the two halves 106a and 10617 of the interconnecting elements, the interconnecting elements are made of an elastomeric material.  
  Each half 106a and 10612 has a pair of flanges 121 and 122 extending outwardly therefrom, as seen in FIGS. 14a, 14b and 140. These flanges 121 and 122 receive the thick panels or boards 102 therebetween to hold the panels or boards in engagement with the disc 103 (see FIG. 142). If one of the boards 102 happens to be too thin to be tightly engaged between two sets ofthe flanges I21 and 122, a shim such as the shim 127 shown in FIG. 14d. may be placed around the flanges as shown in FIG. 140 to take up the slack. Each interconnecting element 106 has auxiliary flanges 128 thereon, which serve to hold the shims 127 in place on the flanges 121 and 122.  
  From the afore-described arrangement, it is readily seen that the coupling or disc 103 can connect together thin sheets. such as glass (not shown) and thick panels, such as boards 102, by receiving the thin sheets in the slots 21 and receiving the boards 102 between the flanges 121 and 122.  
  In FIG. 15 and 16 is shown in which way a number of separate [shaped clamping pieces 5-4-5 can be interconnected to a connecting element according to the invention. In both cases the clamping pieces have triangular extensions 30, whereby four of these triangular extensions can be shifted onto each other in such a way that a square is formed. Each of the triangles is provided with an opening 31 into which a pin 32 of a connecting member 33a, 33b fits in a clamping way. According to the embodiment according to FIG. 15 the connecting member consists of two caps 33a and 33b, of which the one 33a is provided with pins 32 and the other 3311 with openings not visible in the figure. For the interconnection of the clamping pieces the pins 32 of cap 33a are inserted through the openings 31 of the triangular extensions and the openings of the cap 33!).  
  In the embodiment according to FIG. 16 the connecting member also consists of two caps 33a, 33b, which, however, both are provided with pins 32 as well as with openings 34; the openings 31 in the triangular extensions 30 ofthe I-shaped clamping pieces 5-4-5 are elongated and can each receive a. pin 32 of the cap 33a and a pin 32 of the cap 33b. In mounted position the end of a pin of cap 33a will fall into an opening 34 next to a pin of cap 33b, and the other way around. One of the caps can be provided with a centering member fitting into recesses at the opposite angle points of the triangular extensions 30. If less than four clamping pieces per 1 connecting element according to the invention are applied triangular filling pieces are applied to the place which would be destined for the triangular extensions if four clamping pieces would be applied.  
  Referring now to FIG. 17, there is shown a main coupling, designated generally by the numeral 36, which mates with a plurality of interconnecting elements, designated generally by the numeral 42. The main coupling 36 is cruciform in shape with four arms, designated generally by the numerals 4343, which extend outwardly from a main core 44. Each arm 43 mates with one of the interconnecting elements 42 (only one of which is shown) to interconnect four of the panels 2 so as to radiate from the core 44 of the main coupling 36. Since the main coupling 36 is cruciform in configuration, two panels 2 will extend in a vertical plane of FIG. 17 as drawn.  
 Each panel 2 has a slot 46 formed therein, which slidably receives one of the interconnecting elements 42. f  
 In order for the interconnecting elements 42 to seat securely in the slot 46, each interconnecting element 42 has a top flange 47 and a bottom flange 48, which engage opposite sides 49 and 51 of the panel 2, respec tively.  
  In the embodiment illustrated in FIG. 17, flanges 47 and 48 are U-shaped so as to extend around the periphery of the opening forming the slot 46.  
  The flanges 47 and 48 are joined by a web 52 which, in the illustrated embodiment, is also generally U- shaped to conform to the U-shaped configuration of the flanges. The web 52 has a bend formed along line 53 occurring therein, so as to form a dove-tail type opening 54 within the interconnecting element 42 to receive one of the arms 43 from the main coupling 36.  
  Each arm 43 of the main coupling 36 is formed into an upper fork 57 and a lower fork 58 separated by a slot 59. Each of the forks 57 and 58 have converging sides 61 and 62, respectively, which converge toward the slot 59. When the arm 4.3 is received in the dovetail opening 54 of the interconnecting element 42, the upper arm 61 fits between the bend 53 and the top flange 47, while the lower fork 58 is received between bend 53 and the bottom flange 46. Preferably, the lower portion 520 of the web 52 and the upper portion 52b of the web 52 converge toward the bend 53 at the same angle that the sides 61 and 62 of the arm 43 converge toward the slot 59. However, since the element 46 is made of an elastomeric material and the webs 52 can be relatively flexible, at least along the bend 53, the angles assumed initially by the upper and lower portions 52b and 52a of the web 52 may be different from the angles of the walls 61 and 62, so that when the arm 43 is dove-tailed with the slot 59, the web 52 will deform slightly to conform with the shape of the arm 43. This will result in a tight fit between the sides or surfaces 61 and 62 and the interior surface or surfaces of the web 52. This will also force the exterior surfaces of the web 52 against the sides of the slot 46 in which the element 42 is seated.  
  In order to further rigidify the interconnecting between the main coupling 36 and the interconnecting elements 42, each arm 43 of the main coupling is relieved at the top and bottom surfaces of the forks 57 and 58, respectively, to form a land 66 and a shoulder 67 thereon. Since only the land 66 and shoulder 67 of the top fork 57 is shown, only the relationship between the top fork and the top flange 47 will be explained, but it should be understood that the lower fork 58 has a land 66 and a shoulder 67 thereon, which are similar in structure and function to the land and shoulder on the upper fork. When the arm 43 is dove-tailed in the interconnecting element 42, the land 66 engages the lower side 68 of the flange 47, while the shoulder 67 engages the inner surface 69 of the flange. This causes the outer lower surface 71 of the flange 47 to engage the top surface 49 of the panel 2 more tightly. Since both the top and bottom forks 57 and 48 have lands 66 and shoul ders 67 engaged similarly with the top and bottom flanges 47 and 48, respectively, the various aforementioned elements of the arm 43 and interconnecting elements 42 will seat in tight engagement.  
  Additional rigidity is obtained in the aforementioned interconnection by a pin 71 which is passed through aligned holes 72 and 73, respectively, in the top and bottom forks 57 and 58 of each arm 43. This prevents the top and bottom forks from tending to skew out of alignment in relation to one another, so that they form an angle therebetween which might tend to tilt the panels 2 out of the illustrated planes. This skewing could be caused by either one or both of the forks 57 and 58 starting to bend as they extend from the core 44 of the main coupling 36. Finally, according to the illustrated embodiment, the web 52 and the flanges 46 and 47 terminate in ends 76 and 77, respectively, which engage shoulders 78 on the core 44 and the shoulders 67 on the adjacent arms. In the illustrated embodiment, this engagement will occur only with those elements 46 connecting panels 2 extending in the same plane. The elements 46 connecting panels 2 extending in a plane perpendicular to this plane will have end portions that will abutt with only the outer surfaces of the top and bottom flanges 47 and 48.  
  Referring now to FIG. 18, there is shown a main coupling, designated by the numeral 81, which is similar in configuration to the coupling or plate-shaped body disclosed in applicants prior U.S. application, Pat. No. 3,687,500, issued Aug. 29, 1972. The coupling 81 has four slots 82 which extend therein and are spaced 90 apart so that, in terms of the orientation shown in FIG. 18, four panels 2 may be connected together to extend in horizontal and vertical directions. For purposes of clarity, only one panel 2 is shown in FIG. 18.  
  The panel 2 has a thickness 83 which is greater than the width 84 of the slots 82 and, therefore, an arrangement needs to be made so that the panels 2 can be connected to the coupling 81. This is accomplished by making a slot 86 in each panel 2 to receive an interconnecting element, generally designated by the numeral 87.  
  The interconnecting elements 87 have a rib portion 88 which extends between and connects a pair of web portions 89-89 between which it extends. The thickness of the rib 88 approximates the width 84 of the slots 82, so that the ribs may be received in the slots. The width of the slots 88 approximates the width 91 of the coupling 81, so that as the rib 88 is received in the slots 82, the coupling 81 will be received between the webs 89. The length of each interconnector 87 is such that the rib 88 will fill the entire slot 82. In this way, a snug relationship is achieved between the interconnectors 87 and the coupling 81.  
  In order to firmly seat each interconnector 87 in the slots 86 formed in the panels 2, each interconnector has top flanges 9494 extending outwardly and normally to the webs 89, and bottom flanges 9696 extending normally and outwardly from the bottom of the webs 89. The interconnecting elements 87 can, by the afore-described structure, enable one to use the couplings 81 to connect together relatively thick panels 2 and, thus, allow the couplings 81 to have a more general utility than is disclosed in US. Pat. No. 3,687,500.  
  All the connecting elements discussed have in common that they comprise a number of fixedly or detachably interconnected clamping pieces of which the crosssection have the shape of an I or a double dove-tail or a shape derived therefrom. Further many varieties are possible.  
 What we claim is:  
  1. A system for interconnecting relatively thin sheets to one another and to relatively thick panels and for interconnecting relatively thick panels to one another and to relatively thin sheets, comprising:  
 interconnecting means for fitting into slidable engagement with the relatively thick panels;  
 flange means extending from said interconnecting means for overlying opposite sides of the relatively thick panels to effect a tight fit between the panels and the interconnecting means; and  
 coupling means having a plurality of slotmeans therein, said coupling means slidably receiving said interconnecting means to secure the relatively thick panels to the coupling means, said slot means having a width approximating the thickness of the thin sheets and extending in the coupling means for receiving the thin sheets and retaining the thin sheets on the coupling means.  
  2. The apparatus of claim 1, wherein said slot means is received in said interconnecting means to retain the relatively thick panels on said coupling means.  
  3. The apparatus of claim 2, wherein the interconnecting means has a rib which extends thereacross having a thickness that approximates said slot means and which is received in said slot means when said coupling is received by said interconnecting means.  
  4. The apparatus of claim 2, wherein there are a plurality of said slot means disposed at intervals in said coupling means.  
  5. The apparatus of claim 4, wherein said coupling means has a central portion and four arms projecting therefrom, each of which contains one of said slot means and each of which is received by one of said interconnecting means.  
  6. The apparatus of claim 5, wherein the interconnecting means has webs which extend between said flanges and which converge toward one another to form a slot, and wherein the arms have surfaces thereon which converge toward one another to approximate the convergence of the webs, so that the arms dove-tail into engagement with the slots formed by the converging webs.  
  7. The apparatus of claim 1, wherein the interconnecting elements are formed into two halves having projecting portions extending therefrom, and wherein the coupling means has openings extending therethrough into which the projecting portions of the interconnecting elements fit when the interconnecting elements are mounted on the coupling means.  
  8. The apparatus of claim 7, wherein shim means are secured to the flange means projecting from said interconnecting means to allow relatively thick panels to be retained on said coupling means.  
  9. A system for interconnecting panels of various thicknesses, comprising:  
 interconnecting elements having oppositely facing flanges extending therefrom for engaging opposite sides of the panels and webs extending between the flanges to connect the flanges together;  
 coupling means having arms extending therefrom for nesting with said interconnecting means by sliding between said oppositely disposed flanges; and  
 slot means extending in each of said arm means for receiving relatively thin panels therein to connect the relatively thin panels to the panels engaged by said interconnecting means.  
  10. The apparatus of claim 9, wherein each arm means has an aperture extending therethrough which registers with said slot means and receives a pin therethrough to rigidify said arm means when said arm means is nested with said interconnecting means.  
  11. An apparatus for interconnecting relatively thick panels to relatively thin sheets, comprising:  
 interconnecting means having pairs of upper and lower flange portions projecting outwardly therefrom for engaging opposite surfaces of the thick panels;  
 a pair of web portions for connecting the upper and lower flanges to one another;  
 a rib portion extending between the web portions;  
 and  
 coupling means having a plurality of slots therein for receiving the rib means therebetween and for receiving relatively thin panels therein.  
  12. The apparatus of claim 11, wherein the slot means are disposed at intervals in said coupling means.