It is important for office furniture in a modern style to have a clean and efficient appearance, and to embody the modernistic ideals that"form follows function"and"less is more". This is particularly true where office furniture is manufactured from functional materials such as sheet metal. However, problems encountered in the assembly of office furniture, as well as the need to strengthen edges of the sheet metal from which the office furniture is built, lead to characteristics that give the impression of wasted material and space.

Specifically, the front of a cabinet, credenza, or other office furniture of the same general type, will typically include doors, as well as a"reveal"or front edge that is the part of the carcase of the office furniture surrounding the doorway that receives the doors. This reveal will typically have to be thicker than a few thicknesses of sheet metal in order to impart the required strength to the reveal. This thickened reveal may give the impression of wasted material and wasted space, as, other things equal, thickening the reveal reduces the cross-sectional area of the doors.

This problem is exacerbated by a further problem associated with sliding doors. Specifically, the doors on office furniture may slide within tracks installed in the doorway of the office furniture carcase. Typically, the door is installed into these tracks by being hoisted up into a channel of a top track, swung vertical, and then dropped into channel of the bottom track. This design inevitably leads to the upper track having a very deep channel as this depth is required to accommodate that portion of the height of the door that must be accommodated for the door to clear the bottom track. As a result,

the upper track will take up a lot of space and may give the impression of inefficient use of space and materials. Further, when the door is installed between the upper track and the lower track, the top of the door will fit loosely within the channel of the upper track, which may result in a rickety fit and give the impression of shoddy manufacture.

Accordingly, a method of constructing office furniture having only a thin reveal, and in which the tracks for sliding doors are snug about the sliding doors is desirable.

An object of one aspect the present invention is to provide an improved reinforced metal sheet structure.

In accordance with an aspect of the present invention there is provided a reinforced metal sheet structure comprising a metal sheet and a reinforcing member. The metal sheet has a folded edge and the reinforcing member is for reinforcing the metal sheet at the folded edge thereof. The reinforcing member has an extended thin edge and is attached to the metal sheet so that the extended thin edge abuts the folded edge of the metal sheet.

Preferably the reinforcing member is a T-hat. In the preferred embodiment, the metal sheet structure is for use in the construction of office furniture.

An object of another aspect of the present invention is to provide an improved sliding door assembly.

In accordance with another aspect of the present invention there is provided a sliding door assembly for attachment to a door frame. The sliding door assembly comprises a lower track for attachment to a base of the door frame, an upper track for attachment to the top of the door frame, a sliding door means for installation in the lower track and upper track, and a track-

securing means for securing the upper track and the lower track having the sliding door means mounted therebetween to the door frame. The sliding door means has a lower track-engaging means for sliding engaging the lower track and upper track-engaging means for sliding engaging the upper track.

Preferably, the upper track has an upper channel for accommodating the upper track-engaging means of the sliding door means and a downward projection for securing the upper track-engaging means of the sliding door means in the upper channel, and the lower track has a lower channel for accommodating the lower track-engaging means of the sliding door means and an upward projection for securing the lower track-engaging means of the sliding door means in the lower channel. The sliding door assembly is dimensioned such that when the upper track and lower track having the sliding door means mounted therebetween is installed in the door frame, a first distance from a top surface of the upper channel to a top end of a lower projection is less than the height of the sliding door including the lower track- engaging means and the upper track-engaging means, and a second distance from a bottom surface of the bottom channel to a bottom end of the upper projection is less than the height of the sliding door including the lower track-engaging means and the upper track-engaging means.

An object of a further aspect of the present invention is to provide an improved method of installing a sliding door.

In accordance with a further aspect of the present invention there is provided a method of installing a sliding door in a door frame comprising sliding engaging a sliding door between an upper track and a lower track, then positioning the upper track and lower track and the sliding door engaged therebetween in the door frame, and the securing the track to the door frame.

A detailed description of the preferred embodiments is provided herein below with reference to the following drawings, in which: Figure 1, in a perspective view, illustrates a cabinet in accordance with the preferred embodiment of the present invention; Figure 2, in a perspective exploded view, illustrates the cabinet of Figure 1; Figure 3, in a sectional view of arrows 3-3 of Figure 1, illustrates the cabinet of Figure 1; Figure 4, in an enlarged sectional view of the cabinet of Figure 1, shows a method of installing sliding doors; Figure 5a, in an enlarged sectional view of the doors of Figure 4, shows a pair of steel sliding doors; Figure 5b, in an enlarged sectional view of the doors of Figure 4, shows a pair of glass sliding doors; and Figure 6, in an exploded perspective clamshell view, illustrates details of, an interlocking relationship between T-hats of a top panel and a left side panel of the cabinet of Figure 1.

Referring to Figure 1, there is illustrated in a perspective view, a cabinet 20 according to a preferred embodiment of the invention. This perspective view of Figure 1 is shown exploded in Figure 2. The cabinet 20 includes sliding doors 22a and 22b. The sliding door 22a is constructed of glass, while the sliding door 22b is constructed of steel. It will be appreciated by those skilled in the art that the cabinet 20 would typically include two glass doors or two steel doors, instead of one of each. Figures 1 and 2 show a cabinet having glass sliding door 22a and a steel sliding door 22b for illustrative purposes. The glass door 22a includes glass holders 46, which, in turn, include plastic guides 44. Plastic guides 44 are configured to slide within door track 42. Steel door 22b also includes plastic guides 44 (not shown in Figure 1).

The cabinet 20 additionally comprises a top panel 24, side panels 26, a back panel 28 and base panel 30. Each of the side panels 26 has an upper flange 26b for supporting and attachment to the top panel 24 and a base flange 26c for supporting and attachment to the base panel 30. The back panel 28 also has an upper flange 28a for supporting and attachment to the top panel 24, a base flange 28b for supporting the base panel 30, and two side flanges 28c for attachment to the side panels 26. Each of side panels 26 is reinforced by separate pairs of side panel T-hats 32. As shown in the drawings, each T-hat is preferably a channel section element bent from sheet metal, usually sheet steel having a top hat-like cross-section. That is, each T- hat comprises a channel section with a flange extending laterally outwardly from the end of each channel side. Back panel 28 is also reinforced by a back panel T-hat 34 and top panel 24 is reinforced at its front end by a front panel T-hat 35. At its base, the cabinet additionally includes a kick panel 36, that reinforces the base panel 30, as well as leveller brackets 38, each of which has a threaded support leg 40.

T-hats are attached to the face of the panels to which they are applied.

The leveller brackets 38 at the back of the cabinet 20 are attached to the base flanges 26c and 28b of the side panels 26 and back panel 28 respectively at the juncture of the base flanges 26c and 28b. The leveller brackets 38 at the front of the cabinet 20 are attached to the ends of the kick panel 36, and the ends of the assembled kick panel 36 and leveller brackets 38 are attached to the base flanges 26c of side panels 26. All of these attachments can be accomplished by conventional mechanical fastening arrangements-such as screws, rivets, nuts and blots for example-but preferably the elements are spot-welded together, or, where there is difficulty in accessing a part with a spot welder, are tack--welded.

Referring to Figure 3, there is illustrated, along the lines 3-3 of Figure 1, a sectional view of the cabinet 20. The sectional view of Figure 3 is shown discontinuous in order to fit all of the features of interest onto a single page.

Top panel 24 includes a front edge or J-section 24a. As shown, the front

edge or J-section 24a has been formed by bending back-crush bending-a portion of the front edge. This front edge is reinforced by a leading edge 35a of top panel T-hat 35, resulting in a finished front edge that is three thicknesses of sheet metal and is smooth-edged as well as being quite strong and thin. At the left base of the cross-sectional view of Figure 3, kick panel 36 is shown surrounding leveller bracket 38 and supporting the left (front) end of base panel 30. The back end of base panel 30 is supported by another leveller bracket 38. The base panel 30 rests freely on these supporting elements. The height of each corner of the cabinet 20 can be independently adjusted using the threaded support leg 40 of each leveller bracket 38.

Referring to Figure 4, there is illustrated, in an enlarged sectional view of the doors of the cabinet 20, a method of installing the sliding doors 22b.

As illustrated in Figure 3, J-section 24a of top panel 24 is reinforced by leading edge 35a of T-hat 35. As shown in Figure 4, a doorway is defined by T-hat 35 and by kick panel 36, as well as by J-sections 26a of side panels 26 (shown in Figure 6) into which the door assembly, including tracks 42 engaged with doors 22, can be inserted. On insertion, screw-receiving apertures 42a of tracks 42 align with screw-receiving aperture 35b in T-hat 35 and with screw-receiving aperture 36a in kick panel 36. Both of the sliding doors 22b are slid out, of the way of the apertures at one end of the front of the cabinet at which point self tap screws 48 are inserted through screw- receiving apertures 42a and into screw-receiving apertures 35b and 36a to secure one end of the tracks 42 in the cabinet. Then the doors 22 are slid to the other side of the cabinet 20 and selftap screws 48 are inserted through the screw-receiving apertures 42a and screw-receiving apertures 35b and 36a on the opposite side of the cabinet 20. As a result of this method of inserting the tracks and doors, a very snug fit may be achieved, as there is no need to insert the doors 22 after the tracks 42 have been installed. Also, in the event that repairs to the doors 22 or tracks 42 are necessary, it is a comparatively simple matter to unscrew the selftap screws 48 and remove the doors 22 and tracks 42.

Each of the tracks 42 shown in Figure 4 includes a channel that is completely occupied by plastic glides 44. The lower channel includes a bottom surface 56 and upward projection, and the top channel includes a top surface 52 and a downward projection 50. Three dimensions h,, h2 and h3 are shown in Figure 4. The dimension h, is the total height of the door 22 including plastic glides 44. The dimension h2 is the distance from the lower channel bottom surface 56 to the upper channel downward projection 50.

The dimension h3 is the distance from the upper channel top surface 52 to the lower channel upward projection 54. The components are dimensioned relative to the doorway in which they fit such that h, is greater than each of h2 and h3. This inequality expresses the snug fit provided by the tracks 42, which snug fit is permitted by the fact that the door 22 need not be removable from the tracks 42 while the tracks 42 are in the doorway.

Referring to Figure 5a, there is illustrated in an enlarged sectional view, steel sliding doors in accordance with an embodiment of the invention. The steel sliding doors 22b include plastic glides 44 for sliding within the tracks 42.

Tracks 42 are secured to top panel T-hat 35 at their upper end and kick panel 36 at their lower end by selftap screws 48 as described in relation to Figure 4.

Referring to Figure 5b, there is illustrated in an enlarged sectional view, glass sliding doors 22a in accordance with an embodiment of the invention. The glass sliding doors 22a are held by glass holders 46, which include plastic glides 44 for sliding within the tracks 42. Tracks 42 are secured to top panel T-hat 35 at their upper end and kick panel 36 at their lower end by self tap screws 48 as described in relation to Figure 4.

Referring to Figure 6, there is illustrated in an exploded clamshell view, details of the interlocking arrangement between the top panel 24 and the left side panel 26. An analogous interlocking arrangement exists between the top panel 24 and the right side panel 26. As shown, the side panel T-hat 32 includes a cut-away portion 32b that accommodates a full-length portion 35d

of top panel T-hat 35 at the juncture of top panel 24 and side panel 26 where side panel T-hat 32 and top panel T-hat 35 overlap. Similarly, the top panel T-hat 35 includes a cut-away portion 35c that accommodates a full-length portion 32c of side panel T-hat 32 where side panel T-hat 32 and top panel T- hat 35 overlap.

Other variations and modifications of the invention are possible. All such modifications or variations are believed to be within the sphere and scope of the invention as defined by the claims appended hereto.