Abstract:
A unitary connector for connecting hollow muntin bars transversely includes one end with barbed projections or hooks which engage openings in the planar sides of the tubular muntin bars and which also include an opposed plug which engages the hollow open end of a muntin bar. The connector includes laterally extending tabs to engage opposed panes of glass.

Description:
BACKGROUND OF THE INVENTION 
     To provide a double glazed window with the appearance of a tranditional divided lite window having smaller panes separated by conventional muntin bars, it is customary to provide intersecting muntin bars between the panes of glass. To permit air between the panes to circulate over the muntin bar dividers, spacers called bumper buttons are adhered to the outer faces of the muntin bars or to cruciform connections joining the bars. Providing these buttons and assembling them during the production of the window adds cost to the product. 
     The internal muntin bars are usually assembled in a cruciform design, one bar intersecting another at right angles. To accommodate windows of varying size, tubular muntin bars are cut to the desired length and assembled with a plastic cruciform connector having four plugs disposed at 90° to each other, which slide into the open ends of tubular muntin bars. The bars are uniform and generally rectangular in cross section. The design is modular, it being necessary only to cut the bars to length and assemble them with the plastic cruciform connector. One of the problems in using plastic connectors is that gases and particulate matter evolve from the plastic material forming the cruciform connector at the high temperatures that prevail between the glass panes when exposed to sun light. These materials, such as polyethylene, polypropylene and some nylon compositions, may fog the glass, especially if the area enclosed by the muntin bars forming one lite does not permit air circulation within the entire space between the panes. Materials emitted by the connectors may include wax products, light oils, silicones and other materials present in the manufacturing process of the connectors. 
     THE INVENTION 
     The object of this invention is to provide a unitary connector which serves to interconnect intersecting tubular muntin bars and simultaneously provide a spacer to support the panes of glass above the plane of the internal muntin bars. Thus separate button spacers required by the prior art are completely eliminated. Another object is to provide a connector which joins an open end of a tubular muntin bar with the side wall of an intersecting muntin bar. The connector of the invention is molded from substantially less volume of plastic material and consequently reduces proportionately the gaseous or particulate material that can evolve. The connector may be used to assemble cruciform muntin bars without any tools since it frictionally engages the end of one tubular muntin bar with openings in the side wall of the intersecting muntin bar. In a preferred form of the invention the connector has hooks that slide through openings in the wall of a bar and lock against pulling out to insure a tight connection. By providing a single connector which also functions as a spacer, the cost of separate spacers and the labor to assemble and stock them is reduced or eliminated. 
     Thus an object of the invention is to provide an improved connector for muntin bars. 
     Another the object is to provide an improved connector of reduced volume relative to prior art connectors. 
     Another object is to provide a connector which also serves as a means for spacing the muntin bars from a pane of glass. 
    
    
     THE DRAWINGS 
     These and other objects and advantages of the invention will become apparent from the following description when read in conjunction with the accompanying drawings in which; 
     FIG. 1 is a plan view of a cruciform of two intersecting tubular muntin bars interconnected by means of the connectors of the invention; 
     FIG. 2 is a sectional view taken along the line to 2--2 FIG. 1 and which shows the bars disposed between panes of glass; 
     FIG. 3 is a front elevational view of the connector of the invention; 
     FIG. 4 is an end elevational view of the connector shown in FIG. 3; and 
     FIG. 5 is a side elevational view of the connector shown in FIG.3. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     As shown in FIGS. 1 and 2, a tubular muntin bar 10 is interconnected with an intersecting tubular muntin bar 12, 16. The bars are preferably formed from aluminum. The cruciform is disposed between two panes of glass which are mounted in parallel relation in a frame, not shown. The connector indicated generally at 14 has an intermediate plate or rectangular disk 26. A reticulated plug 22 extends from the inner face of the plate 26 and a pair of hooks 18, 20 project from the outer face of the plate 26. Tabs 24 project from the top and bottom edges of the plate 26 to provide spacers for the panes of glass 25, 27 which are mounted adjacent the internal muntin bars. The linear dimensions of the rectangular plate 26 are slightly larger than the internal dimensions of the hollow, generally rectangular cross section tubular muntin bar 12, 16. The plate 26 is disposed between the cut end of bars 12, 16 and the side walls of bar 10. The edges of the plate 26 should be coincident with the outer surfaces of the walls of the tubes 12, 16. Only the tabs 24 project above the surface of the tubular muntin bars. The connector is integrally molded from a thermoplastic material such as modified type 6 nylon. 
     Referring to FIG. 3-5 the reticulated plug 22 of connector 14 consists of a pair of spaced flanges 30, 32 projecting at right angles from the plane of the plate 26. A central H-shaped rib 34 extends between the flanges 30, 32 and has a front and rear cross member 38, 34. The front cross member 38 connects integrally with the inner face of plate 26. Lateral ribs 36 project from the flanges 30, 32. It will be noted that these lateral ribs are inclined toward the plate 26. The lateral edges of the rear cross member 34 are tapered away from the plate 26. This design facilitates insertion of the reticulated plug 22 into the end of the hollow tubes 12, 16. The lateral edges of the cross members 34 and 38 and of the lateral ribs 36 bear against the inside surfaces of the wall to hold the connector firmly inside the tube. 
     A pair of hooks 18, 20 are provided on the outer face of the plate 26. The hooks are V-shaped and because they are molded from a resilient plastic material, the free ends 21 of the hooks will flex inwardly to permit the hooks to pass through openings 28 in the side walls of the tubular muntin bar 10. The distance 42 between the free end 21 of the hook and the outer surface of the plate 26, is approximately equal to the thickness of the side walls 44, 45. Thus when the hooks are pushed through the openings, the free ends spring out and bear against the surface of the side wall to lock the connector in place. 
     As shown in FIG. 2 the tabs 24 provide a space 46 between the surfaces of the muntin tubes and the inner face of the glass panes 25, 27. Thus air and any gaseous particulate or material which may evolve from the plastic is not confined within a single lite bounded by the muntin bars but may circulate freely throughout the entire area within the window frame. In the preferred embodiment, the connector 14 is made from a modified type 6 nylon material. 
     By providing connectors which join one end of a tubular muntin bar with the side wall of an intersecting muntin bar the size of the connector is reduced by about one half. This in contrast to the prior art connector of cruciform design which had four plugs each fitting into one end of the intersecting tubular muntin bars. Thus the amount of volatile material emitted of evolved from plastic at elevated temperatures is significantly reduced. 
     With the present invention, a single connector may be used for all joints. That is the connector disclosed may be used in lieu of a cruciform connection, to connect muntins at a T-connection and even to form a corner. Also, it should be noted that the connector 14 may include tabs 24 only on one side thereof thereby enabling construction of a double pane window having one pane abutting the muntin bar and the second pane spaced from the bar to permit circulation. 
     While a preferred embodiment has been described, various alternative embodiments may be utilized within the scope of the invention which is limited only by the following claims and their equivalents.