So-called "demountable" interior partition wall systems have been available from Partition Components, Inc. (Markham, Ontario), the Gold Bond Building Products Division of National Gypsum Company (Dallas, Texas), and Gravity Lock Systems, Inc. (Houston, Texas) since at least the issuance of U.S. Patent Nos. 3,948,011 and 4,128,979 (in 1976 and 1978, respectively). Both those prior patents are disclose a two-part suspension clip for demountably supporting gypsum wall board from an erect support or framework having horizontal channel members mounted thereto on which the clip rests when affixed to the gypsum board. Although these demountable wall systems have been improved over the years to the point that the only tool need for their installation is a rubber mallet, labor costs are such a significant component of the cost of the finished partition wall that efforts to reduce the time to install such walls continue.

Much of the effort to simplify the installation of such walls has focused on the suspension clip, which has proved to be the most important component of a demountable wall system. Such clips have undergone evolutionary changes such as are shown in U.S.

Patent No. 4,245,448, issuing in 1981 and showing the clip in an embodiment in which it is available commercially to this day. However, such clips require the assembly of two pieces to support the wall board, and that assembly increases the time required to install the wall.

Until recently, all the patents directed to improvements of this suspension clip, for instance, U.S. Patents Nos. 4,693,047 and 4,811,539, issued to National Gypsum Company in 1987 and 1989, respectively, and 5,435,111, issued to GNS UK Limited in 1995, as well as an International Application No. WO 91/14057 which appears to correspond in content to that U.S. Patent No.5,435,111, disclose two piece clips.

Recently, several patents/patent applications have been issued/published which disclose single piece clips. So far as is known, the first was disclosed in U.S. Patent No.

5,060,434, which issued in 1991. The clip disclosed in that patent was modified in U.S. Patent No. 5,216,859, which issued in 1993 on an application which was a continuation- in-part of the application which issued as Patent No. 5,060,433, the rights to both patents currently being owned by Gravity Lock Systems, Inc. Since then, a single piece clip has

been disclosed in PCT Application No. WO 83/02635 and in U.S. Patent No. 5,531,052, the latter being licensed to Partition Components, Inc. and Gravity Lock Systems, Inc.

However, the clips shown in U.S. Patent Nos. 5,060,434 and 5,216,859 are of limited utility and are very different in structure than the clip of the present invention. The clip disclosed in U.S. Patent No. 5,531,052 is expected to be of much greater utility. However, the clip disclosed in U.S. Patent No. 5,531,052 still leaves room for improvement, especially in one aspect noted in that patent, namely, the structure of that clip which enables the clip to be affixed to wall board at a site remote from the site at which the wall is to be erected.

A clip which can be affixed to the wall board at a remote location enables such economies as the use of automated equipment for simultaneously affixing several clips to a gypsum board panel and the shipping of the panel, having the clips affixed thereto, to the location of the vertical support structure to which the panel is to be mounted. Alternatively, such structure enables the use of a separate crew on site which, for instance, uses a die or other instrument for precisely locating the clips on the panel and applies them to the wall board quickly and accurately for a second crew to use to mount to the vertical support structure. It is, therefore, an object of the present invention to provide a clip having structure which facilitates affixation of the clip to a gypsum board panel or other type of wall board at a location other than the location of the vertical support structure to which the panel is to be mounted.

The structural feature of the clips disclosed in the aforementioned U.S. Patent Nos.

3,948,011, 4,128,979, 4,245,448, and 5,531,052 which confers upon them an advantage over all other known clips, regardless of whether they are two-piece or unitary clips, is the structure which confers upon those clips their 'Wcamming" action when mounted to the vertical support structure. This advantage results from the provision of a bearing surface on the clip which is angled relative to the gang nail plate which comprises a portion of the clip, and which is therefore also angled relative to the gypsum board panel to which the clip is affixed. This angled bearing surface engages the horizontal support members of the vertical support structure to draw the gypsum board panel tight against the studs of the vertical support structure as a result of the weight of the panel. This camming action helps provide a finished wall in which adjacent gypsum board panels are drawn flush with each other so as to improve the appearance of the wall and which are effectively retained in that flush relationship and tight against the vertical support structure by the downward force on the panels.

An important aspect of this structure is the need to insure that the angled bearing surface of the clip actually does engage the horizontal support members of the vertical

support structure. In other words, because of the heavy weight and rather unwieldy shape of the gypsum board panel, it is sometimes difficult to insure that the angled bearing surfaces of each of the clips affixed to the gypsum board panel actually engage the horizontal support members when the gypsum board panel is lifted up and against the vertical support structure during the erection of the partition wall. Further, because of the heavy weight of the gypsum board panel and the load which may be affixed to the panel once the partition wall is finished (for instance, by a wall-mounted book shelf and the books which might subsequently be stored on that shelf), it is very important that the angled bearing surface of each of the several clips affixed to the gypsum board panel engage the horizontal support members.

It is, therefore, another object of the present invention to provide a single piece suspension clip for demountably supporting a gypsum board panel or other wall board from a vertical support structure which includes structure which facilitates engagement of the horizontal support member of the vertical support structure by the angled bearing surface of the clip when the gypsum board panel, having the clip affixed thereto, is erected to the vertical support structure.

As described above, the camming action which is so important to the appearance of the finished wall results from translation of the downward movement of the gypsum board panel into movement toward the studs of the vertical support structure. This camming action is advantageous not only during the erection of the partition wall but also after the wall is erected so that the wall board is continuously biased toward the studs of the vertical support structure. Continuously biasing the wall board against the studs improves the appearance of the finished wall. resists rattling of the wall board against the studs, and resists the flexing of the wall board. This continuous camming results from the engagement of the angled bearing surface of the clip with the horizontal support members of the vertical support structure. The clips disclosed in U.S. Patent No. 5,435,111 and International Application Nos. WO 83/02635 and WO 91/14057 lack this feature. Those clips are therefore limited in their utility in the sense that, to obtain a finished wall with the flat, smooth surface required for proper esthetics, the installer must spend extra time installing the wall panels so as to minimize variation from one panel to the next and then, after the panels are mounted to the vertical support structure, taping and floating the joints between panels. Even after taping and floating, the resulting wall rattles and flexes.

It is, therefore, also an object of the present invention to provide a single piece clip which functions to continuously bias the gypsum board panel into engagement with the studs of the vertical support structure to which the gypsum board panel is mounted by action of the

weight of the panel on the angled bearing surface of the clip so that adjacent gypsum board panels.

One of the unique properties of a demountable wall system having a wall board which is erected to the vertical support structure by suspension clips is the ease with which the wall board can be moved laterally once it is supported by the suspension clips on the horizontal support member of the vertical support structure. Even though the gypsum board panel is quite heavy, sliding the gypsum board panel into tight engagement with the adjacent gypsum board panel was a simple matter in light of the structure of the suspension clips.

However, a problem wliich has arisen in connection with the use of a single piece, or unitary, suspension clip such as the clip disclosed in U.S. Patent No. 5,531,052 is that when the wings of the several clips which are affixed to a gypsum board panel rest on the horizontal support member of the vertical support structure, it is the edges of the wings which engage the edge of the horizontal support member. Further, the clips are preferably stamped from a sheet of metal. Likewise, the horizontal support members are preferably made of metal. When the horizontal support member is the type shown in the above- mentioned U.S. Patent Nos. 3,948,011, 4,128,979, 4,245,448, commonly referred to in the industry as a channel member (other types of channel members are also shown in U.S. Patent Nos. 4,693,047 and 4,811,539, issued to National Gypsum Company), the edge of the channel member engaged by the clip is also stamped from a sheet of metal such that the cut edge of the clip engages the cut edge of the channel member.

This engagement of the cut edge of the wings of the unitary metal clip and the cut edge of the channel member makes it difficult to slide the gypsum board panel along the channel member against an adjacent gypsum board panel. Indeed, the resistance to the sliding of the gypsum board panel along the channel member is enough of a problem that it even affects the use of the unitary suspension clip disclosed in U.S. Patent No. 5,531,052 with horizontal support members of the type disclosed in U.S. Patent Nos. 5,060,434, 5,216,859, and 5,426,904 (on information and belief, the latter patent is licensed to Partition Systems, Inc. (Edmonton, Alherta)), in which the edge of the horizontal support member is formed by the folding, or bending, of the metal sheet comprising the support member.

It is, therefore, another object of the present invention to provide a unitary suspension clip having structure which facilitates sliding the gypsum board panel to which the clip is affixed laterally, e.g., along the horizontal support member of a vertical support structure, when the gypsum board panel is erected to the vertical support structure by supporting on the horizontal support member.

Other objects, and the advantages, of the present invention will be made clear by the following detailed description ofthe clip ofthe present invention.

These objects are attained by providing a one piece, or unitary, suspension clip for demountably supporting a gypsum board panel, or other type of wall panel, on the horizontal support member of an erect, or vertical support structure. The clip comprises a substantially flat gang nail plate having a plurality of panel-piercing members extending from one face thereof and a wing, or outwardly extending projection, formed on opposite edges thereof.

The wings are bendable from a first position substantially co-planar with the plate to a second position forming an angle relative to the plate. The clip is affixed to the panel when the wings are in the first position and the panel, having the clip affixed thereto, is mounted on the vertical support structure when the wings are in the second position. Each of the wings is provided with a bearing surface for engaging the horizontal support member of the vertical support structure having a convex curve formed along at least a substantial portion thereof for facilitating engagement of the horizontal support member of the vertical support structure by the wing and camming the gypsum board panel to which the clip is affixed into engagement with the studs of the vertical support structure.

In a second embodiment, the wing of the unitary suspension clip of the present invention is provided with raised edges to facilitate the insertion of a putty knife or other bending tool under the wings to bend the wings from their first position to their second position and so that, once the wings engage the horizontal support member of the vertical support structure to which the gypsum board panel is erected, the gypsum board panel is easily moved from side-to-side along the horizontal support member, thereby facilitating positioning of the gypsum board panel into close proximity with the adjacent gypsum board panel.

In a third embodiment, the unitary suspension clip of the present invention is provided with a stop for preventing insertion of the tool used for bending the wings from the first position to the second position too far under the clip so that neither the clip nor the gypsum board panel to which the clip is affixed are damaged by the bending tool when the wings are bent.

Referring now to the figures, Figure 1 is a top plan view of the unitary suspension clip of the present invention.

Figure 2 is a bottom plan view of the suspension clip of Fig. 1.

Figure 3 is a side elevational view of the suspension clip of Fig. 1 showing the wings of the clip in the first position for affixing to a gypsum board panel or other wall panel.

Figure 4 is a top plan view of the suspension clip of Fig. 1 showing the wings of The, clip in both the first and second positions (the latter being shown in phantom lines) for- engaging the horizontal support member of a vertical support structure.

Figure 5 is a side elevational view of the suspension clip of Fig. 1 showing the wings of the clip in the second position for engaging the horizontal support member of a vertical support structure.

In more detail, the unitary suspension clip of the present invention is indicated generally at reference numeral 10 in the figures. The clip 10 is comprised of a generally rectangularly-shaped gang nail plate 12 having upper 14 and lower 16 portions with a plurality of panel-piercing members 18 extending from one face 20 thereof. In a particularly preferred embodiment the clip 10 is stamped from a piece of galvanized steel. The die utilized to stamp the clip 10 from the piece of metal preferably introduces a twist into each of the panel-piercing members 1 8 of about 60° (from straight) as they are punched, but the degree of twist is set out for purposes of exemplification, not limitation. The twist of the members 18 functions to increase the "grip" of the clip 10 to a gypsum board panel, and this enhancement can be accomplished with a twist of some (instead of all) of the panel-piercing members and/or with a twist of as little as 5-10° from straight. Although reference is made herein to a gypsum board panel, it will be apparent from This disclosure that the clip of the present invention is used to advantage to mount any type of wall board or panel to a vertical support structure.

A transverse line of weakness, indicated generally at reference numeral 22, extends substantially across the plate 12 between the upper and lower portions 14 and 16, respectively, thereof. The line of weakness, as taught by U.S. Patent Nos. 4,128,979 and 4,245,448, is formed of a combination of aligned, inwardly extending notches 24 and/or slots 26 cut in plate 12 or in the edges of plate 12 as the case may be, about which plate 12 bends to improve anchorage of the clip 10 to a gypsum board panel 28 (shown in Fig. 4) under applied loads as more completely described in those two patents, the disclosures of both patents being incorporated herein in their entirety by this specific reference thereto.

As best shown in Figs. 1 and 2, a wing 30 is formed integrally with plate 12 along the opposite edges 32 thereof, e.g.. along the long sides of the rectangularly-shaped plate 12, and extends outwardly from edge 32. One edge 34 of wing 30 is angled relative to the long edge 32 of plate 12 and is formed by the channel 36 which extends inwardly from the edge 32 of the plate 12. Channel 36 is formed at an acute angle relative to the edge 32 of plate 12 and extends inwardly therefrom to terminate at a point spaced inwardly from the edge 32 of

the plate, thereby forming a part of the line of weakness 22. The edge 34 of wing 30, which will be referred to herein as a bearing surface for reasons set out below, therefore.extends outwardly from the long edge 32 of plate 12 at an angle relative to the edge 32.

A second line of weakness is formed in the plate 12 along the long edge 32 thereof by the slots 38 cut in plate 12 from a point near the notch 24 at the inside end of the channel 36, in a direction substantially co-linear with the edge 32 of the plate 12 to a point adjacent the notch 25 formed in the same edge 32 of the plate 12 on the side of wing 30 opposite channel 36. The second line of weakness fonned by the slots 38 between plate 12 and wing 30 weakens the plate 12 so that the wing 30, which comprises the portion of plate 12 outside that line of weakness, is easily pivoted by bending from a first position (shown in Figs. 1-3) in which the surface of wing 30 is substantially co-planar with the surface of plate 12 to a second position (shown in Figs. 4 and 5) in which the surface of wing 30 forms an angle relative to the surface of plate 12 and gypsum board panel 28.

When in this second position, the wing 30 extends from plate 12 in a direction opposite the direction of the panel-piercing members 1 8 and from the face 40 opposite the face 20. In this manner, the bearing surface 34 of wing 30 and the surface 40 of plate 12 form an inverted "V," best shown in Fig. 5, for receiving the edge of the horizontal support member (not shown) of a previously-erected vertical support structure. As used herein, the phrase "vertical support structure" refers to the wall studs and horizontal support members described in the above-incorporated U.S. PatentNos. 4,128,979 and 4,245,448, as well as the vertical support structure shown in the above-referenced U.S. Patent Nos. 4,693,047, 4,811,539, 4,837,988, 5,060,434, 5,216,859, 5,435,111, and 5,426,904. Because the edge 34 of wing 30 rests on the edge of the horizontal support member, thereby supporting the gypsum board panel 28 to which the panel-piercing members 18 of plate 12 are engaged on the vertical support structure, the edge 34 is referred to herein as a bearing surface. As shown in the above-referenced U.S. Patent No. 5,531,052, the edge of the horizontal support member of the vertical support structure on which the bearing surface 34 rests does not extend all the way to the top of the acute angle formed by the bearing surface 34 and the face 40 of plate 12. Instead, the bearing surface 34 of wing 30 functions to pull the gypsum board panel 28 tight against the face of the stud of the vertical support structure as the weight of the gypsum board panel causes the edge of the horizontal support member to slide along the bearing surface 34 upwardly towards the inverted "V," effectively camming the gypsum board panel 28 into engagement with the studs and, coincidentally, into alignment with any adjacent such panels (also not shown).

The positioning of the bearing surface 34 of the horizontal support member at-a position in which the edge of the horizontal support member does not extend all the way up into the acute angle formed by the inverted "V" of clip 10 is important for a second reason.

Specifically, after the gypsum board panel 28 is erected to the vertical support structure by resting the bearing surface 34 on the horizontal support member, gravity causes the bearing surface 34 to slide down over the edge of the support member. The provision of a bearing surface 34 which is long enough that the bearing surface slides only part way down that edge insures that the action of gravity on gypsum board panel 28 can cause the bearing surface 34 to slide further down over the edge of the horizontal support member. In this manner, the camming action is continuous, i.e., gypsum board panel 28 is continually biased against the studs of the vertical support structure.

As a result of this continuous camming, the gypsum board panels of the partition wall resist flexing and rattling. Further, if several of the clips 10 pull part way out of the gypsum board panel (for instance, as a result of excess applied load on the panel or the wetting of the panel), this continuous camming action helps compensate for the "looseness" of the panel which would otherwise result.

An important aspect of this ability of the clip 10 of the present invention to cam the gypsum board panel 28 to which it is affixed into engagement with the studs of the vertical support structure and into alignment with the adjacent gypsum board panel (not shown) is to insure that the bearing surface 34 of the wings 30 rests on the horizontal support member.

Further, because of the weight of the gypsum board panel 28 (and the load applied to the gypsum board panel by, for instance, shelving which may be mounted to the finished wall), it is important that the wings of each of the clips affixed to an individual gypsum board panel engage the horizontal support member. Because of the difficulty in lifting the heavy panel into place on the vertical support structure and the fact that, when the wings are bent upwardly from the first to the second position as described below, not all of the wings will be bent at the same angle, catching the horizontal support member with the wings of the clips of the present invention can be problematical. Consequently, the bearing surface 34 is provided with a convex curve 42 along at least a substantial portion of the length Thereof.

The convex curve 42 along bearing surface 34 serves at least two functions. First, the convex curve opens up the inverted 'V" described above between the face 40 of plate 12 and bearing surface 34 so as to increase the likelihood of "catching" the edge of the horizontal support member when the gypsum board panel 28, having the clip 10 affixed thereto, is erected to the vertical support structure. The second function of the convex curve

along bearing surface 34 is to cause the gypsum board panel 28 to be cammed into tighter engagement with the studs of the vertical support structure than is achieved with a straight- bearing surface 34. This enhanced camming action results from the mechanical advantage conferred upon the structure of clip 10 by the greater effective angle of the curved portion 42 of bearing surface 34 relative to the surface 20 of plate 12 as compared to the angle of, for instance, the straight bearing surface of the clip shown in the aforementioned U.S. Patent No.

5,531,052. This mechanical advantage is of particular utility in enhancing the continuous camming action ofthe clip ofthe present invention as described above.

As shown by the shadow lines in Figs, 1, 3, and 5, the edges of the wings 30 are bent upwardly, or dished, at reference numeral 44 so that the wings 30 are slightly concave when viewed in the plan view shown in Fig. 1 (convex when viewed in Fig. 2). In other words, the side of the wings 30 which is adjacent the gypsum board panel 28 (the side of the wing which is continuous with the face 40) is convex so that the edges of the wing 30 are raised slightly up off of the surface of gypsum board panel 28. These raised, or dished, edges 44 serve at least two functions. First, when the wings 30 are bent from the first position to the second position (Figs. 4 and 5), the dished edges 44 facilitate insertion of a putty knife or bending tool (not shown) in the manner described below for use in bending the wings 30.

The second function of the dished edges 44 is to facilitate the sliding of the gypsum board panel 28 to which the clip 12 is affixed along the horizontal support member of the vertical support structure (not shown) when erected thereto, the dished edges acting to decrease the resistance to the movement, or sliding, of the cut edges of the wing 30 along the cut edge of the horizontal support member.

Because one object of the clip of the present invention is to improve the economics of its use, the clip is affixed to the gypsum board panel 28 at a location remote from the site at which the gypsum board panel is erected to a vertical support structure to form a partition wall. To facilitate affixing the clip 10 to gypsum board panel 28 at a location other than the location of the vertical support structure, the wings 30 are not quite co-planar with the face 40 of plate 12. Instead, the wings 30 are angled upwardly from a co-planar position by approximately 2" toward the second position as shown in Fig. 5. This slight angling of the wings 30 is shown at reference numeral 46 in Fig. 4. This slight bend 46 toward the second position is accomplished at the time the clip 10 is stamped or when the clip is affixed to gypsum board panel 28. If the latter, the bend is accomplished in a number of ways.

Depending upon how weak the line of weakness formed along the edge 32 of plate 12 by slots 38 is, the slight upward bend 46 results from the driving of the panel-piercing members

1 8 into the panel, i.e., if the plate 12 is considerably weakened along the second line of weakness and affixed to gypsum board panel 28 by application of pressure or impact on the portion of The face 40 of plate 12 other than wings 30, the gypsum board panel under plate 12 is compressed enough that the uncompressed portion of the gypsum board panel causes the wings 30 to bend upwardly from the surface of the gypsum board panel. That upward bend 46 can also be accomplished by interposing a thin piece of metal or other material (not shown) between the wing 30 and panel 28 (but not between the face 20 of plate 12 and panel 28) when the clip 10 is affixed to the gypsum board panel.

Once applied to gypsum board panel 28, the wings 30 must be bent from the first position to the second position so that gypsum board panel 28 can be erected to the vertical support structure. The bending of the wings is accomplished by, for instance, inserting a putty knife or other tool (not shown) between the wing 30 and the surface of gypsum board panel 28 to which the clip 12 is affixed and then levering or prying the wing 30 upwardly from the surface of gypsum board panel 28. Insertion of the putty knife, however, can damage the surface of the gypsum board panel or, more importantly, partially pry the clip 10 out of gypsum board panel 28. For this reason, the face 20 of plate 12 is provided with a stop, in the form of the dimple 48 (best shown in Figs. 2 and 3), located along the second line of weakness at the edge 32 of plate 12, to prevent the putty knife from being inserted too far under the plate 12.

Although described in conjunction with the embodiment shown in the figures, certain variations in the component parts of the embodiment shown which do not change the manner in which those component parts function to achieve their intended result are intended to fall within the scope of the following claims.