US3186782A

US3186782A - Knock-down cabinet construction

Info

Publication number: US3186782A
Application number: US207639A
Authority: US
Inventors: Jr Myron E Ullman
Original assignee: Mullins Manufacturing Corp
Current assignee: Mullins Manufacturing Corp
Priority date: 1962-07-05
Filing date: 1962-07-05
Publication date: 1965-06-01
Anticipated expiration: 1982-06-01

Description

June 1, 1965 M. E. ULLMAN, JR

KNOCK-DOWN CABINET CONSTRUCTION 7 Sheets-Sheet 1 Filed July 5, 1962 INVENTOR.

ATTORNEYS June 1, 1965 M. E. ULLMAN, JR 3,186,782

KNOCK-DOWN CABINET CONSTRUCTION Filed July 5, 1962 7 Sheets-Sheet 2 INVENTOR.

MYRON E. ULLMAN, JR-

June ,1, 1965 M. E. ULLMAN, JR

KNOCK-DOWN CABINET CONSTRUCTION 7 Sheets-Sheet 3 Filed July 5, 1962 Ill-z 80 I 58 INVENTOR.

MYRON E. ULLMAN, JR.

BY Aswana. i

2 8 7 "v 5 A u. 4 I, 6/ n. mm a .w v a n.

H6. IO

FIG. ll

iiuwu TTO N EYS June 1, 1965 M. E. ULLMAN, JR 3,186,782

KNOCK-DOWN CABINET CONSTRUCTION Filed July 5, 1962 7 Sheets-Sheet 4 INVENTOR.

MYRON E. ULLMAN, JR.

June 1, 1965 E. ULLMAN, JR

KNOCK-DOWN CABINET CONSTRUCTION 7 Sheets-Sheet 5 Filed July 5, 1962 lOl' FIG. I6

uvmvrox. MYRON E. ULLMAN, JR.

June 1, 1965 M. E. ULLMAN, JR 3,186,732

KNOCK-DOWN CABINET CONSTRUCTION Filed July 5, 1962 7 Sheets-Sheet 6 FIG. I9

' INVENTOR. MYRON E. ULLMAN, JR.

Y FIG. 2| mom ATTOR EYS June 1, 1965 M. E. ULLMAN, JR 3,136,732

KNOCK-DOWN CABINET CONSTRUCTION Filed July 5, 1962 1 7 Sheets-Sheet 7 INVENTOR. I26 MYRON E. ULLMAN, JR.

AT TOR EYS {mill 3,186,782 KNQCII-BQWN CABINET EGNS'IRUC'IIIIN Myron Illlrnan, In, Canrleld, Ghio, assignor to'P/iuiiins Manufacturing (Iorporation, Warren, Ghio, a corporation of Qhio Filed Italy 5, 1952, Ser. No. 2-fi7,639 iaims. (Ill. 312-263) This invention relates to a sheet metal cabinet construction and particularly to a new and novel method of assembling prefabricated and prefinished panels to form a rigid cabinet body structure which can be assembled economically at the point of use.

It is well known that so called knock-down cabinet constructions are economical from the standpoint of packaging, storage, and shipment because of savings in space. Knock-down construction also permits complete surface coverage of individual component parts with enamel finishes, which is impossible when applying a finish to a factory assembled and welded structure.

One of the principal objects of this invention is to provide simple locking means between adjoining preiinished panel members with universal application to an entire line of kitchen cabinetry including wall, linen, broom, utility, oven, base and undersink cabinet body structures. Field assembly can be carried out with a minimum of separate fastener means and tools to attain a rigid structure.

Another object of this invention is to provide interlocking means between main cabinet wall members and interior article supporting members to give strength and rigidity to the assembled cabinet body structure.

Another object of this invention is to provide a novel hinge bracket for interlocking vertical front panel members to horizontal front panel members for strength and rigidity of the assembled cabinet body structure.

Another object is to provide hinge brackets for a knock-down cabinet body structure for mounting cabinet doors in accordance with United States Patent No. 2,835,359.

Other objects will become apparent from the following description of the accompanying drawings, in which- FIGURE 1 is a perspective view of an assembled wall cabinet body structure, shown with door panels removed for purposes of clarity.

FIGURE 2 is a perspective exploded view of a cabinet body structure.

FIGURE 3 is a section of a lanced hook along line 33 of FIGURE 2.

FIGURE 4 is a section of clearance holes in back panel shown along line 4-4 of FIGURE 2.

FIGURE 5 is a section of .a lanced hook along line 5-5 in rear flange of end panel of FIGURE 2.

FIGURE 6 is an enlarged fragmentary sectional view along offset vertical planes indicated by lines 66 of FIGURE 1, showing the inter-relationship of basic components.

FIGURE 7 is a fragmentary top view of a front corner showing the relationship of hinge bracket, end panel and top panel.

FIGURE 8 is a fragmentary front view of the same upper front corner showing relationship of hinge bracket, end panel and top panel.

FIGURE 9 is a sectional view along line 99 of FIG- URE 8 showing hinge and end panel locating detents or embosses.

FIGURE 10 is a front upper center fragmentary view showing the relationship of hinge brackets, top panel and a vertical mullion.

' of FIGURE 10 showing the interlocking relationship of 7 hinge brackets, top panel and mullion.

FIGURE 12 is a perspective view of one of a pair of hinge brackets required for mounting each door.

FIGURE 13 is a sectional view showing the relationship of the rear center support for a long shelf panel and the lanced hook of FIGURE 3 in the back panel mem ber.

FIGURE 14 is a partial sectional view along line 14-44 of FIGURE 8 showing the front mullion and flanges of an end panel.

FIGURE 15 is a perspective view of a composite base cabinet body structure upon which a work top, sink or other cabinet body structure may be placed, andwhich shows one possible assembly of prefinished elements using difierent height door closures, drawer support guides, shelves, front and back mullions and a strike channel.

FIGURE 16 is an enlarged fragmentary View along the I plane indicated by lines 16-16 in FIG. 15.

FIGURE 11 is a sectional view taken along line 11--11 FIGURE 17 is a sectional view taken along lines 17-fl7 of FIGURE 21 of drawer guide rear tab in locked position with a vertical back mullion.

FIGURE 18 is a sectional view taken along line 18-48 of FIGURE 21 showing interlock of rear drawer guide tab in locked position with rear vertical flange of right hand end panel.

FIGURE 19 is a sectional view taken along line 19-19 of FIGURE 16 showing interlock of drawer guide front tab with notch in inturned flange of front mullion of right hand end panel.

FIGURE 20 is a sectional view taken along line 2tl-2d of FIGURE 16 showing hinge bracket assembly to right hand end panel to secure horizontal strike channel interlocked in notch of inturned flange of end panel front mullion.

FIGURE 21 is an enlarged fragmentary section taken along the partial plane indicated by lines 21-21 of FIG- URE 15 showing drawer and shelf supporting means in back mullions, rear flange of an end panel, and the back panel member.

FIGURE 22 is a perspective fragmentary view of the lower front corner of a left hand end panel of a base cabinet body.

FIGURE 23 is a fragmentary sectional view showing a kick plate hooked to the recessed vertical flange portion of left hand end panel shown in FIGURE 22.

FIGURE 24 is a perspective view of a vertical center mullion for wide base cabinet body structures having multiple compartments. 7

FIGURE 25 is a perspective view of a vertical rear mullion for supporting rear shelf flanges and rear drawer guide tabs.

FIGURE 26 is a perspective view of a left hand drawer guide of a pair of left and right hand guides for support ing sliding drawers.

The wall cabinet FIG. 1 illustrates one of several possible embodiments of a wall cabinet structure contemplated by this invention. Basically, the body structure comprises the following panels: a top 50, ends 51 and 52, a back 53, a floor 54, and a bottom 55. In addition a shelf 56 is shown mounted within the body structure formed by the aforesaid panels.

Referring now to FIGS. 1, 2 and 6, top panel 50 has a depending front flange terminating with an inturned flange 8'5, and a rear flange 8t) terminating in hookedge portion 82. As best shown in FIG. 2, portions of front flange 8d are provided with pairs of adjacent clearance n (9 counter-part of each other, only the structural formation of panel 51 will be described in detail. As best shown in FIGS. 2, 6 and 14, end panel 51 has top and

bottom flanges

70 and 71, front mullion 66 with

inturned flanges

67 and 68, and a'back'flange 69.

Referring more particularly to FIG. 6,

flanges

67 and 68 are notched at their upper. and lower end portions to receive top panel 50 and floorand bottom 54 and 55.

Flanges

67 and 68 are-also notched as at 72 to receive and support the front edge of shelf 56. Back flange 69 is lanced, as shown in FIG. 5, to form hooks 73 for sup porting rear flange 84' of shelf 56, and rear flange 87' of floor 54. i

' As illustrated in FIGS. 2 and .6, the upper portion of back panel 53 is provided with an angular offset 76, a vertical flat portion'77, and a top right angle flange 78 which terminates in a down turned flange 79. As a result flange 79 is received in and interlocks with hook-edge portion 82 of top 50 as shown in FIG. 6. 'Along the sides and adjacent the edges of the main vertical flat portion of back panel 53,rectangular holes 74 are provided to re ceive hooks '73 which project from flanges 69 of

end panels

51 and 52. Additional lanced hooks 75am pro videdin the center of the main vertical portionof panel 53 to provide center support to back flange 84' of shelf 56 and rear flange 87' of floor'54. i

Bottom panel 55, as shown in FIGS. 2 and 6, has upturned

end flanges

96 and 96, a rear upturned flange 91' and a front edge formation which has a front face portion 91, an inturned upper flange 94, and an inturned lower portion 92 which is spaced above the main flat panel area by a right angle offset portion 93. As illustrated in FIG. 2, front face 91 has one or'more rectangular holes 97 to receive catches for door strikes not shown herein. Clearance holes 100 are provided in the ends of front face 91 for lower detents 98 in end panels'Sl and 52, and bolt holes'95. Bottom 55 rests on bottom flanges 71'of end panels 51 and 52.,

As shown in FIGS. 2 and 6, floor panel 54, which has downturned

end flanges

88 and 88, and front and rear

downturned flanges

87 and 87,"rests on bottom 55 with front flange 87 supported on the ledge formed by portion 92, while end flanges 88 and, 88' are supported on the floor panel end flanges 96 and 96' and the rear flange 87 is locked against back panel 53 by the lower hooks 73 in end panel rear flanges 69. Floor panel 54 is further securely held in position as a result of its front flange 87 resting in abutment with inturned flange 94 of bottom 55. Notches 90in front flange 87'clear catches inserted in holes 97 of front face or mullion 91 of bottom 55. End notches 89 inflange 87 are for clearance 'of hinge bracket mounting means presently described.

FIGS. 8 and 9, which are front and side views respectively, of the upper left topcorner of the wall cabinet, show how a hinge bracket 58 (FIG. 12) is located by inserting the rear projection of detent 60, provided on bracket 58, into receiving detent 98 which is formed in front mullion 66 of end panel 51, and by inserting a pan head bolt 61 through holes 63 in the hinge bracket and aligned holes 99 in end panel .

mullion

66 and 95 in mullion 80 of top panel 50. Hole 100 in'mull-ion 80 of top panel is large enough to clear detent 98 in end panel mullion 66. The offset 65, which is formed on hinge bracket 58 (FIG. 12), abuts on the surface of mullion 80 so as'to take up the metal thickness of end panel mullion 66, which is in lapped abutment with the outer surface of mullion "80. When the nut is tightened on bolt 61, this corner becomes quite rigid against any movement of any of its parts.

In the event it is desired to have a wide cabinet with four doors, FIG.' 1 showsthe use of a center vertical mullion57 and two additional pairs of

hinge brackets

58 and 59. The mounting of the toppair of hinge brackets is shown in FIGS. 10 and 11. In this case the receiving detents 98 for hinge detents are formed on the front face of mullion 57 adjacent its upper. and lower edges. Thus bolts 61 secure the hinge brackets to vertical mullion 57 and front mullion of top panel 50. The bottom endof vertical mullion 57 is similarly attached to front mullion 91 of bottom panel 55 adding further rigidity to a wide cabinet body, structure while supplying additional door mounting means.

It is understood .that cabinet body structures may be assembled similarly whether one, two or more doors are required to serve as front closures. It is also understood that one or more shelves may be used and each made adjustable by providing additional notches 72 in

end panel flanges

67 and 68 depending on the body height, and corresponding flanges of any center mullions required. Furthermore when additional or adjustable shelf locations are desired, additional appropriately positioned lanced hooks 73 and 75 in end panel flanges 69 and back panel 53, respectively, are made to suit.

The assembly of a cabinet body structure from the component panels and members herein described is relatively simple. The back panel 53 is placed on a flat surface, top panel'50 is hooked onto top flange 79 by its hook edge 82. Each of the end panels, 51 or 52, is positioned at the appropriate end of panel 50 so that the upper edge of top panel 50 is under top flange 70 of the end panel, and hooks 73 are received in rectangular holes 74 of back panel 53. The upper front corners are then fastened by assembling

hinge brackets

58 and 59 as above described and as shown in FIGS. 7 and 8. The bottom panel 55 is then positioned between the opposite end panels 51 and 52', so as to rest on flanges 71'. The lower front hinge bracket is assembled as was the top bracket. Another pair of

hinge brackets

58 and 59 are then secured to the lower front corners. If a single door cabinet is involved, bolts 61 are used without the hinge brackets inserting them through upper and lower end panel holes 99, and top and bottom panel holes of the unhinged upper and lower front corners. Floor panel may then be placed on top of bottom panel 55 with its rear flange portion 87' engaged by hook 73 and its front flange 87 resting on portion 92 of panel 55. A shelf 56 may then be placed within the cabinet and supported in front notches 72- and rear hooks 73 of each end panel and also by upper hook 75 of back panel 53. g

It will become apparent that when the floor panel 54 and one or more shelves 56 are in place, back panel 53 is firmly locked in position, since back flange 84 of the shelves 56 and back flange 87' of the floor panel 54 are between hooks 73 of the end panels and hooks 75 of the back panel member 53, thus holding back panel in place and adding strength and rigidity to the cabinet body structure.

The base cabinet The basic principles of construction which are the subject matter of this invention and which were used to provide the wall cabinet assembly described above, may also be employed in the construction of a base cabinet. One embodiment, of the many arrangements which are possible, is shown in FIG. 15.

Any arrangement in a single base cabinet unit can be combined with one or more similar units so that only one pair of end panels will be required by using intermediate front and rear vertical mullions to separate the various storage compartments. A top channel frame and floor panel govern the overall length of the body structure.

The combination base cabinet structure shown in FIG. 15 has a set of

end panels

151 and 152, a top channel frame upon which'is secured a'separate worktop, sink, or range top, or, combinations thereof, none of which are shown here since this invention deals only with the cabinet body structure. In addition, the cabinet structure has a partial back panel or panels 153, floor panel 154, kick plate 155, front mullion 157,

rear mullions

158 and 159, a horizontal strikechannel-160 and a pair of drawer support guides 161 and 162 (FIG. 21).

Since

end panels

151 and 152 are dpposite counterparts, a reference to the basic structural arrangement of either one will likewise pertain to the other. The top of

end panels

151 and 152 have an inturned flange 101, and down turned flange 162 which hooks over the ends of top channel 150 as shown in FIG. 21 at 101' and 102 which are the corresponding flanges of end panel 152. The front flange 103 forms a vertical mullion having an inturned flange 104. Inturned flange 104 has a series of notches 1155 and 1116 spaced to determine the proper location and front support for drawer guides 161' and 162, shelves 156 and strike channels 160. Rear inturned flange 107 of end panel 151 has a series of lanced brackets 198 and lanced hooks 109, alignedv with front flange notches and 106, respectively. By these means drawer guides 161 (FIG. 26) and 162 are supported by inserting hook portion 126 into notch 165 and the wedge shaped flange into lance bracket 1118. Shelf 156 is supported by inserting its front flange portion into notch 196 and by hooking its rear flange 135 over hook 109, as shown in FIG. 16.

The upper and lower portions of front mullion 163 have provisions for mounting a pair of

hinge brackets

58 and 59 with detent-s and holes 98 and 99, respectively (FIG. 20), as described above in relation to the end panel front mullions and hinge brackets of wall cabinets.

The lower front corners of

end panels

151 and 152 are cut out to provide toe clearance inasmuch as the end panels rest on the floor of the room in which they are installed. In FIG. 22, a partial perspective view of the lower front corner of end panel 151 shows the

flanging

111, 112, 113 and 114 which define the toe clearance space. Bottom inturned flange 110 of end panel 151 rests on the floor of the installation area.

Flanges

113 and 114 support the front corners of floor 154 of the cabinet body structure.

inturned flanges

111 and 112 are shown in partial section in FIG. 23 in relation to the interlocking of a kick plate 155. FIGS. 15 and 16 show

end panel members

151 and 152 and a hooked bracket 135 which is spot welded to the back of kick plate 155 and which slides into hooked and locked relationship with

flanges

111 and 112.

A front vertical mullion 157 is shown in FIG. 24 with top inturned flange 117 and downturned flange 118 which hooks over front channel member 136 (FIG. 15) of top frame 150. Bottom flange 119 supports the front center portion of floor 154. Detents 98 and holes 99 in the front face of mullion 157 are for mounting

hinge brackets

58 and 59 previously described in relation to the wall cabinet body structure. Notches 155 and 1116 in inturned side flanges and 116 are aligned with and correspond to similarly identified notches in end panel flanges 1114 and 19d of

end panels

151 and 152, respectively.

The smaller notches 1135 provide location and support for front lanced hooks 126 in drawer guides 161 (FIG. 26) and 162. FIG. 16 shows the interlock of drawer guide front hook 126' in notch 1115 of end panel 152.

FIG. 15, 16 and 20 show the manner of supporting and locking strike channel 169 in large notches 166. The hook means 131 formed on the inturned flanges at the opposite ends of the front web portion of the channel 160, fit into notch 166 of flange 104, and over the unnotched portion of flange 115. of center mullion 157. Hinge bracket 59 (FIGS. 16 and 20) fits into detent 98 nearest to flange 115 of mullion 157 and bolt 61 secures strike channel 169 to the mullion using hole 63' of hinge bracket as shown in FIG. 12. Rectangular holes 97 in strike channel 169 are to receive strike catches, not shown. Shelf 156, as shown in FIG. 16, is similar to the shelving used in the previously described wall cabinet, and is supported at its front channel edge by notches 1% in mullion 157 and by hook 169 in end panel 152.

Floor 154 has the same exterior dimensions as top channel frame 150, and its front corner edges are supported by

flanges

113 and 114 of end panel 151, and by corresponding

flanges

113 and 114 of end panel 152 as shown in FIG. 16. The center front section of floor 154 is supported by flange 119 of mullion 157 (FIGS. 15 and 24).

It is noted here that end panel flanges 194 and 194' and mullion 157 side flanges 115 and 116'are notched out at the top to clear top channel frme 150. Likewise the bottom portions of these flanges are notched to permit entrance of the front edge section of floor 154-. The front edge faces of both top frame 151? and floor 154, have clearance holes 108 for receiving detents 98, and holes 95 to receive bolts 61 for the mounting of

hinge brackets

53 and 59

toend panel members

151 and 152, as well as to vertical mullion 157. As shown in FIG. 16, kickplate 155 has an outward turned top flange 1353 Supporting floor panel 154, and inturned bottom flange 134 in the same plane as the bottom flanges 11d and 11d of

end panels

151 and 152.

A pair of rear

vertical mullions

58 and 159 are shown in position in FIG. 21. The right rear vertical mullion 159 is shown in perspective in FIG. 25 and has an angular cross section with a back leg 129 and a forward leg 121. Back leg 12% has a top inturned flange 122 and downturned flange 123 which hooks over the rear channel section 137 of top frame 15%). Leg 121 is notched out at the top to clear top channel section 137 when

flanges

122 and 123 of

mullions

158 and 159 are hooked over it. Floor panel 154 is supported, in part, by having its rear flange portion 135 in resting engagement within notch 124, and also within the wide angled hook 125 formed in back leg 12% of

mullions

158 and 159.

The back legs 12% of

mullions

153 and 159 have a number of lanced hooks 169 and lanced brackets 1118 corresponding in structure and position with hooks and brackets in inturned back flanges 1117 and 1117' of

end panels

151 and 152. A portion of lanced hooks 159 are aligned with front flange notches 166 for supporting shelves at diflerent locations within the cabinet. Lanced brackets 1193 are aligned with front flange notches 1115 for locating and supporting drawer guides 161 and 162; Rear flange orv tab 127 of drawer guide 161 has a reduced portion slightly tapered as at 128 which fits into lanced bracket 1118 and notch 129 serves as a stop against the side of 103 lanced bracket as shown in FIG. 21. The positioning of guide 162 is shown similarly in FIG. 21.

Back panel 153 while of less height than the full height of the end panels, extends from the floor toa height about half the height of the end panels. Rectangular holes as at 74 in back panel 53 shown in FIG. 2 fit over the lanced hooks 1199 and lanced brackets 1%. Either the back flanges of shelves and floors in lanced hooks 1119, or the rear flange tab 127 of the drawer guides in brackets 1138 lock the back panel to the inside of flanges 167 of the end panels and back leg 12!) of rear

vertical mullions

158 and 159 as shown in FIGS. 16 and 21.

Top frame 151) is rectangular and made up of channel sections and 137 as shown in FIGS. 16 and 21. Gussets 132 are welded at each corner for stiffness. Front channel member 136 acts as a strike channel with rectangular holes 97 for strike catches not shown, and

top supported drawer in sliding position in a pair of.

drawer guides 161 and 162. The assembly of a base cabinet body structure is similar to the procedure followed in assembling the wall cabinet structure.

It will be understood that two or more compartments may be provided in a single base cabinet body structure and any combination of shelves and drawers may be used slides, all serving to provide a rigid, sturdy structure zontal strike channel located intermediate the top andbottom panels ofthe cabinet body, similar to that-shown above for base cabinets, but are adapted to receive two sets of" strike catches and two pairs of. hinge brackets. The additional-mounted hinge brackets add greatly to the rigidityof. these tall narrow cabinet. structures which also have full height locked in back panels for additional strength.

' Thesetallcabinets are readily adapted for installations of built-in ovens located at. convenient. working heights, with doors mounted above. and. below the oven. Shelves, drawer guides and oven supporting means are readily installed using the notches located inend panel flanges, and the combination ofv mounted hinge brackets,horizontal front mullions, and locked in back wallpanelmembers, assure the. strength and rigidity. required for, such. an installation.

Having thus. described my invention, what I now claim is" horizontal front mullions for inserting and securing asingle fastener means to form a rigid corner structure and hinge bracket mounting.

2. In a cabinet body structure assembledfrominterlocking prefinished panel members, the combination of,

rear vertical flanges of vertical panel members, a back panel-member, shelf panels nadother article supporting means Withinthe cabinet body, wherein the, vertical rear flanges. of vertical panel members have lanced hooks and brackets therein for supporting the rear downturned flanges of shelves or flanges of other article supporting means,

clearance holes along the vertical, edges of said back panel member for the lanced hooks and brackets of vertical rear flanges of vertical panel members, the back 1. In a cabinet body structure assembled from inter-' panel member being placed against the rear flanges of. the vertical panelmembers so that the lanced hooks and brackets protrude inwardly through the clearance holes so thatthe rear down-turned shelf flanges and flanges of other internal articlesupporting' means are supported by the lanced hooksand brackets andatthe same time hold the back panel member securelyin relation to adjoining flanges of verticalpanel membersf 3. In a cabinet body structure inaccordance with claim 1, inwhich'at leastthree front corners formed by vertical end panels and:horizontal top and bottom body structure members aresecuredagainst inovement by interfittinghinge brackets. i i I i 4. In a cabinet body structure in accordance. with claim 3, comprising in addition a horizontal strike channel member extending parallel to said horizontal front mullion and-atleast two interfittinghinge brackets being securedto said horizontal strike channel member. 7

,5. In a cabinet body structure assembled.- from interlocking prefinishedfcomponents consisting of top, bottom, end, back and front components, wherein front mullion portions of. top, bottom and end components are secured-to each other and to any separate front mullion components by single fasteners in each hinge bracket attachedtoa pair of: vertical. and horizontal adjoining front mullion surfaces, said hinge bracket being located.

on verticalmullion surfaces by projections and depressions of matchingdetents embossed in saidlhinge. bracket and in saidfr ont vertical mullion surfaces spacedrelative to said single fasteners to prevent twisting of. said hinge brackets relative to said front mullion surfaces.

References, Cited; by theExanziner UNITED I STATES PATENTS

Claims

1. IN A CABINET BODY STRUCTURE ASSEMBLED FORM INTERLOCKING PREFINISHED PANEL MEMBERS, THE COMBINATION INCLUDING A FRONT CORNER OF THE BODY STRUCTURE FORMED BY ADJOINING VERTICAL AND HORIZONTAL FRONT MULLIONS OF VERTICAL AND HORIZONTLA PANEL MEMBERS, A HINGE BRACKET HAVING A DETENT EMBOSSED THEREIN, A DETENT FORMED IN THE FRONT MULLION OF THE VERTICAL PANEL MEMBER TO RECEIVE SAID HINGE BRACKET DETENT EMBOSS, CLEARANCE FOR SAID DETENT IN THE FRONT MULLION OF THE HORIZONTAL PANEL MEMBER, ALIGNED HOLES IN THE HINGE BRACKET AND ADJOINING VERTICAL AND HORIZONTAL FRONT MULLIONS FOR INSERTING AND SECURING A SINGLE FASTENER MEANS TO FORM A RIGID CORNER STRUCTURE AND HINGE BRACKET MOUNTING.