Tamper-proof window unit
BACKGROUND OF THE INVENTION 
     Tamper-proof window units for use in steel doors and the like have been available in the past and have been generally satisfactory. Such units, however, have normally employed tamper-proof bolts which have not always wholly obviated tampering and which have required drilling through the steel doors adjacent the window openings, providing hole layouts or templates to align door and window frame holes and, in the case of U.L. labelled fire doors, pre-drilling at the factory prior to shipment has been required. Still further, maintaining the parts of the window frame and the associated pane of glass in desired relative positions during shipment and installation has proven unwieldy and somewhat inefficient. 
     SUMMARY OF THE INVENTION 
     The general object of the present invention is to provide an improved tamper-proof window unit having no visible means of attachment from one side and wherein attachment screws are positioned within the door opening eliminating the need for drilled holes, layouts, templates, etc., and wherein a simple and yet effective means is provided for maintaining frame parts and the window pane in desired relative positions during shipment and installation prior to final assembly. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view partially broken away for clarity and illustrating a window unit constructed in accordance with the present invention and a portion of a door associated with the unit. 
     FIG. 2 is a sectional view taken generally as indicated at 2--2 in FIG. 1 and showing a first window frame member and an associated pane of glass. 
     FIG. 3 is a sectional view taken generally as indicated at 3--3 in FIG. 1 and showing a second window frame member. 
     FIG. 4 is an enlarged fragmentary sectional view taken generally as indicated at 4--4 in FIG. 1 and showing both the first and second frame members, the pane of glass, and an edge portion of a door in a condition of partial assembly. 
     FIG. 5 is an enlarged sectional view similar to FIG. 4 but showing the parts in final assembly. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring particularly to FIG. 1, it will be observed that a tamper-proof window unit constructed in accordance with the present invention is indicated generally at 10 and comprises similar first and second similar frame members 12 and 14. The tamper-proof unit is adapted for assembly in doors, partitions, etc., and, as shown in FIG. 1 the unit is assembled in a door 16 with the tamper-proof side toward the viewer. The door may be of steel or other construction and has a multilateral window opening 18, shown in the common form of a quadrilateral or four-sided opening. In accordance with the invention, the window unit is multilateral, and may include a three-sided configuration, a four-sided configuration, etc., and even circular and other arcuate forms which may be regarded as comprising an infinite number of sides. 
     With a quadrilateral window opening as shown the window frame members 12 and 14 are of course also of a quadrilateral configuration and are preferably formed from bent sheet metal although materials of construction may vary widely within the scope of the invention. As stated the frame members 12 and 14 are similar and in the preferred form shown, the said frame members are of identical cross section throughout in their initial stages of forming. Thus, the frame members may be constructed at economic advantage, for example by roll forming or press-brake forming, miter-cut and welded or otherwise joined at corners to provide finished frame members. The first frame member 12 has four small countersunk front to rear openings 13,13 and four screws 15,15 have their heads exposed. Thus, the first frame member may be on an interior or private side of the door 16 while the second frame member 14 has no visible means of attachment and is adapted for the public or tamper-proof side of the door. 
     Each of the first and second frame members has a front panel which is multilateral, quadrilateral as shown, and which takes a narrow elongated configuration extending generally in a plane parallel to the door and marginally about the door opening with an outer edge partially overlapping the door adjacent the opening. Such panels are shown at 20, 22 respectively for the frame members 12, 14 and each panel has top, bottom, left and right hand sides. To provide a finished edge, the outer edge of each of the front panels 20, 22 includes a narrow elongated flange which projects rearwardly toward the door. Such flanges are shown for the panels 20,22 respectively at 24, 26 and each of the flanges has top, bottom, left and right hand sides. 
     Each frame member also has a narrow elongated generally L-shaped integral flange which extends along the inner edge of its front panel and each such flange comprises integral first and second narrow elongated panels. As shown, the front panel 20, FIGS. 4 and 5, has an L-shaped flange with a first panel 28 and an integral second panel 30, while the front panel 22 is provided with an L-shaped flange having a first panel 32 and a second panel 34. Each of the first panels 28, 32 projects generally rearwardly from its associated front panel and, as shown, the flanges 28, 32 project rearwardly and also at a slight angle of inclination inwardly toward the center of the door opening. The second panels 30, 34 project from a rear or inner edge of their respective first panels outwardly with respect to the center of the door opening and in a plane generally parallel with the door faces and the front panels 20, 22. 
     Still referring to FIGS. 4 and 5, it will be observed that the two second panels 30, 34 are spaced apart in parallel relationship to define a groove 36. The groove 36 opens inwardly toward the center of the door opening and is adapted to receive and hold a marginal portion of a pane of glass. Two small layers of mastic 38 and 40 are shown disposed in the groove respectively between the panels 34, 30 and a pane of glass 42. It will be understood, however, that a single layer of mastic such as illustrated at 38 may suffice in a majority of installations. The pane of glass 42 may of the common window type, an impact resistant polycarbonate, or, preferably of the fire retardant type. 
     In accordance with the present invention, the second panel of one of the frame members 12, 14 is divided into first and second sections along each of at least two generally opposite sides of the panel and, as shown, the second panel 30 of the frame member 12 is divided into first and second sections along each of its four sides. Each first section of the panel 30 takes the form of a small tab 44 which is arranged substantially at right angles with the panel and which projects rearwardly toward the second panel on the other frame member 14 and adjacent the marginal edge of the pane of glass 42. That is, each tab 44 is severed and bent through approximately 90° from the panel 30 and, as best shown in FIG. 2, each tab 44 is disposed adjacent the marginal portion of the pane of glass 42. The second section of each side of the panel 30, illustrated at 46,46 resides substantially in the plane of the panel. 
     The second panel 34 of the second frame member 14 is, in accordance with the invention, provided with small front to rear openings in at least two generally opposite sides thereof, and as shown, a small opening 48 is provided in each of the four sides of the panel 34. The openings 48,48 are arranged in front to rear alignment respectively with the aforementioned openings 13,13 in the front panel 20 of the frame member 12. Further, it will be observed that the bending of the tabs 44,44 from the plane of the second panel 30 provides small additional openings or spaces 50,50 vacated by the tabs. The small additional openings 50,50 provide clearance for the screws 15,15, the said screws being entered respectively in the openings 13,13 in the front panel 20 and the openings 48,48 in the second panel 34 of the second frame member 14. Four screws 15,15 are provided as indicated above and may take the form of ordinary sheet metal screws tamper-proof construction being unnecessary. 
     Referring now particularly to a comparison of FIGS. 4 and 5, it will be observed that the pane of glass 42 is held in position against unintended or accidental movement in its plane in a loosely assembled condition of the parts by the tabs 44,44. When the screws 15,15 in the openings 13,13 and 48,48 are thereafter tightened to the condition of final assembly as shown in FIG. 5, the tabs 44,44 serve a second function as stops engaging the second panel 34 of the frame member 14. With the parts in final assembly as shown in FIG. 5 the outer edge flanges 24,26 of the frame members 12,14 clampingly engage opposite sides of the door 16 and the two second panels 30,34, albeit indirectly, clampingly hold the marginal portions of the pane of glass 42. That is, the marginal portions of the pane of glass are clampingly held indirectly by the opposing engagement of the panels 30,34 on the mastic 38,40. A simple and convenient assembly procedure is thus provided and yet a high degree of structural integrity is achieved in assembled window unit. 
     As will be apparent from the foregoing, the tabs 44,44 serve the desired purpose of maintaining the pane of glass 42 in its desired relative position during installation and they also serve the additional stop function during final assembly. The necessary additional or clearance opening for the screws 15,15 is conveniently provided for in the bending of the tabs from the second panel 30. With regard particularly to the tamper-proof feature, it will be observed that there is no visible means of attachment from the public side, i.e., the side of the window unit facing the frame member 14 and there is no necessity to drill holes in the door, the screws 15,15 being engaged with the frame members within the door opening 18. Finally, with the use of tamper-proof through bolts eliminated a small but relatively expensive item of construction is eliminated and in the event of loss, the ordinary sheet metal screws can be easily replaced at the installation site.