Rack with extruded custom struts

Abstract

A rack for holding panels, includes a pair of extruded specially-shaped struts (30, 32) at opposite sides of the rack that enable rapid mounting of a panel (11-15) at any height along the struts. Each strut includes a front mount portion (70) that forms a cavity (72) with a front vertical strip-shaped opening (86) and a pair of flanges (82, 84) at laterally opposite sides of the opening and includes an integral column portion (150) that increases resistance to lateral strut buckling. A side of the panel is supported on the mount portion by a screw (102) that passes through a hole (94) in the panel and that threadably engages a nut (104) that lies in the mount portion cavity and against the flanges. The front-to-rear length J of the cavity is short enough to allow a compression spring (106) to fit in the cavity and press the nut against the flanges until a screw can be installed.

Description

BACKGROUND OF THE INVENTION

Electrical equipment is commonly mounted on a frame that supports electrical components and that includes a front panel, and with switches, displays, etc. accessible from the front of the panel. The panel is mounted on a rack that lies on a floor and that commonly supports a plurality of panels at different heights. One design of such a rack includes a pair of laterally-spaced vertical struts that are joined by beams that keep the struts parallel. Each strut has a front with a vertical row of threaded holes. The most common standard panel width is 19 inches, the lateral spacing between the rows of vertical holes of the two struts is a standard 18 5/16 inches (18.31 inches), and each panel has a plurality of holes at each of its laterally opposite sides that are also spaced by 18.31 inches. A panel is mounted on the rack by projecting screws through the panel holes and into the strut holes, and turning the screws to threadably fix them to the threaded strut holes. Because of the fixed vertical hole spacing, this type of rack often results in large gaps between vertically spaced panels, and because of the strut cross-section previously used this type of rack results in exposed side edges of the panels, both of which detract from the appearance of the rack. Also, in such a rack, a threaded hole in a strut can be damaged, which makes that hole unusable thereafter. Furthermore, the screw rear ends are exposed to the electrical equipment on a frame and can abrade against wires of the electrical equipment.

SUMMARY OF THE INVENTION

In accordance with one embodiment of the present invention, a rack is provided which has struts of simple and sturdy construction that facilitate clamping of panels to the struts at any chosen height, and to avoid large gaps between plates and to avoid the need for threaded strut holes that can be stripped, the struts concealing the laterally opposite edges of the panels and isolating the ends of mounting screws. Each strut is an extruded element of custom cross-section, with a front mount portion on which a front panel can be mounted and with an integral column portion that adds to the stiffness against buckling of the struts under the weight of the panels and equipment thereon. The front mount portion has walls that form a mount cavity with a front that forms a vertical strip-shaped opening, the cavity walls including a pair of flanges at laterally opposite sides of the opening. A side of a panel is mounted on a strut by projecting a screw rearward through a hole in the panel and through the vertical strip-shaped opening, with the screw rear portion being threadably connected to a nut that lies in the cavity. The nut has opposite ends that lie against the rear faces of the flanges. As the screw is tightened on the nut, the nut presses firmly against the flanges, and the panel is clamped between the head of the screw (or a washer thereon) and the front surface of the cavity walls at the flanges.

Each strut preferably has a front projection at its side that projects forward of the mount cavity front wall, by the thickness of a panel. This conceals the edge of the panel and results in a rack with a flush front surface. The walls of the cavity of the front mount portion, preferably include laterally opposite side walls and a rear wall, all of which isolate the rear end of the screw from equipment mounted on a panel. A compression spring holds the nut in position, and the cavity has a limited front-to-rear length to allow the spring to press against the rear wall of the cavity while the spring presses the nut against the flanges, without spring buckling.

The strut is preferably of a shape that allows two struts of identical cross-sections to be used as the two struts that lie at laterally opposite sides of the rack. This can be done by constructing each strut so it is symmetrical about a lateral vertical mid plane, with a rear mounting portion that is identical to the front mounting portion. As a result, when a second strut is used that is identical to a first strut that lies at the first side of the rack, the second strut can be turned 180° about its vertical axis and then serves the same purposes as the first strut at the first side of the rack.

The novel features of the invention are set forth with particularity in the appended claims. The invention will be best understood from the following description when read in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a front isometric view of a rack of the present invention, shown with panels mounted thereon.

FIG. 2 is a partial and sectional rear isometric view of the rack of FIG. 1.

FIG. 3 is a sectional view of one of the struts of the rack of FIG. 2, showing a fastener assembly and a portion of a panel that is mounted on the strut.

FIG. 4 is an isometric view of the fastener assembly of FIG. 3.

FIG. 5 is a sectional view of a strut of another embodiment of the invention.

FIG. 6 is a sectional view of a strut of another embodiment of the invention.

FIG. 7 is a front elevation of a portion of a panel, showing another design of a hole therein.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 shows a rack 10 which supports a plurality of panels 11-15. Each panel generally is part of a frame 20 that supports electrical equipment 22, and each panel may have switches 24 and other controls as well as displays that are accessible from its front face 26. The rack includes a pair of struts, including a first strut 30 and a second strut or second strut element 32 at laterally L opposite sides of the rack, which support the weight of the panels and equipment thereon onto a floor. The upper ends of the struts are held spaced apart at fixed positions by top beams 40, 42. The lower ends of the struts are held spaced apart by lower beams 50, 52 that have flanges 54 that prevent the rack from tipping in forward F or rearward R longitudinal directions M. Applicant notes that the panels 11-15 have laterally opposite edges 60, 62 that lie inward of the laterally outer sides 64 of the struts. FIG. 2 shows that the two struts 30, 32 have identical cross-sections, but are turned 180° from each other.

FIG. 3 shows the cross-section of each strut such as 30, which is uniform along the height of the strut. The strut has a front mount portion 70 with a cavity 72 formed by a pair of laterally opposite cavity side walls 74, 76, and a rear cavity wall 78. The cavity has a front wall 80 formed by a pair of flanges 82, 84 that leave a vertical strip-shaped opening 86 between the flanges. The flanges have a pair of rearwardly-facing flange surfaces at 90s at bumps 90 at opposite sides of the front of the cavity. One side 92 of the panel 11 is mounted on the strut by a screw 102 that passes through a hole 94 in the panel. The screw is part of a fastener assembly 100 that includes the screw 102, a nut 104 and a compression spring 106. The screw has a screw head 110 that presses (through a washer 112) against the front face 114 of the panel. The screw shank 116 passes through the hole 94 in the panel, through the opening 86, and into the cavity. The rear portion of the screw is threadably engaged with the nut, and when the screw is tightened it causes opposite ends 120 of the nut to press against the opposite cavity flanges at the bumps 90 thereon.

When the screw 102 is tightened, it clamps the panel 11 against a front surface portion 122 of the strut, at the flanges 82, 84. The purpose of the spring 106 is to hold the nut 104 at a constant position in the cavity before the screw is installed and tightened. Applicant prefers to attach the front end 124 of the spring to the nut so they remain together. The nut is initially moved to a position close to the desired position at which the panel hole will lie. The panel hole is aligned with the nut and the screw is inserted through them and partially tightened on the nut. The same procedure is performed for all fastener assemblies on each side of the panel. Then, the panel is moved up or down to the precise desired vertical height, and all screws are tightened. Normally, the panel is initially positioned with its panel top edge 130 (FIG. 1) lying spaced below the bottom edge 132 of the panel that lies above it, or below the lower edge 134 of the top beam. Then the panel is raised until its panel top edge lies against the bottom of the next higher panel or the bottom of the top beam, and then all of the screws that will hold that panel in place are tightened. This not only allows a maximum number of panels to be mounted on the rack, but avoids vertical gaps between panels that are unsightly and that allow dust and particles to more easily fall onto the electrical equipment.

FIG. 4 shows that the nut 104 has a width A that is less than its length B between its ends 120. The width A is small enough to allow the nut to be inserted through the vertical opening 86 in the strut, with such insertion facilitated by mounting the nut at the end of the screw 102. Thereafter, the nut is turned 90° so its ends abut the flanges as shown in FIG. 3. The spring could be inserted through the vertical opening even if it had a slightly greater width than the opening.

Applicant constructs the two struts 30, 32 so they are identical but are turned 180° from each other about a vertical axis 140. To this end, the strut 30 of FIG. 3 is provided with a rear mount portion 142 that is identical with the front mount portion and that has a rearwardly-facing vertical opening 144. The strut is symmetrical about a lateral mid plane 146 that extends through the axis 140. In most cases, the rear of the rack is left open so the rear mount portion is not used to hold a panel. However, when the strut is turned 180°, the rear mount portion 142 becomes the front mount portion for the opposite strut 32. As shown in FIG. 2, the formerly rear mount portion 142 then lies opposite the front mount portion 70 of the opposite strut 30.

The strut 30 of FIG. 3 has a column portion 150 which lies beside the front and rear mount portions 70, 142 and that is integral with them. The column portion 150 adds lateral width to the strut and adds material to the strut, other than what is required to form the walls 74, 76, 78, 82, 84 of the mount cavity. The column portion 150 prevents the strut from buckling laterally as indicated at 32B in FIG. 1, despite use in a tall rack. The column 150 (FIG. 3) has a front projecting part 160 that projects forward of the front portion at the flanges 82, 84 by the thickness of the panel such as 11. This keeps the panel lateral side edges from jutting out. Instead, the entire front of the rack, including the panel and the projecting sides of the struts (except for the mounting screws and forwardly projecting controls and displays), are flush to lie in a common plane, for an enhanced appearance. The column portion also has a projecting rear portion 162 that is useful for the other strut. As shown in FIG. 2, the column portions 150 lie at laterally opposite sides of the rack beyond the front mount portions 70, 142.

The strut cross-section of FIG. 3 shows a recess 170 between the front and rear mount portions. This results in a somewhat C-shaped strut, with the recess often not used. The rear mount portion 142 forms a channel 172 that is useful to hold wires. It is easy to install wires in the channel 172. Such wires also can be run through the recess 170 without lengths of wires extending outside the rack. The strut has a longitudinal middle 174 that connects the front and rear mount portions 70, 142.

Applicant prefers to construct the struts by extrusion. Aluminum extrusions are preferred because the dies and the extrusion process are of lower cost than for steel, and because aluminum is corrosion-resistant. Applicant has constructed and successfully tested extrusions of the shape shown in FIG. 3, with the extrusion having a lateral width E of 1.34 inch and a longitudinal length G of 3.00 inches, and used in a rack that supports panels of 19 inches lateral width. Each cavity had a width H of 0.713 inch and a longitudinal length J of 0.643 between the rear cavity wall and the projections on the flanges. The vertical opening had a width K between flanges that was 0.437 inch. It is desirable that the length J of the cavity be no more than twice the width K of the cavity opening, in order that a compression spring of moderate length can be used which will not buckle, and to strengthen the strut. A compression spring can be of wound wire, soft rubber, etc., and applicant prefers that a spring be used that is tapered to prevent buckling.

FIG. 5 illustrates the cross-section of a strut 180 of another design, which has front and rear mount portions 182, 184 of the same construction as in FIG. 3. The strut is symmetrical about a lateral midplane 190 that divides the strut in two. However, the strut does not have a forward projection to conceal the lateral edge 192 of the panel indicated at 194. Also, the strut is far less resistant to strut buckling. A column portion 202 can be added to strengthen the strut against buckling and to provide projections 210, 212.

FIG. 6 illustrates a strut 220 of another design, which is not symmetric about a lateral mid plane 222, and which is about as weak in buckling as the strut of FIG. 5. An added column portion 224 would add resistence to buckling and provide projections. Struts of the same construction as shown in FIG. 6 with the mount portion 224, can be used at opposite sides of the rack by turning a strut upside-down to use the same design at each side. Such upside down turning (turning 180° about a lateral axis) can be used with the struts of FIGS. 1-3 and 5.

FIG. 7 illustrates a side portion of a panel 11, with a hole 230 and with a screw head and screw shank indicated. The hole includes a slot portion 232 that extends to the side edge 234 of the panel. This allows a panel side to be slid sideward into or off of a pair of screws of installed fastener assembles.

Thus, the invention provides a rack and struts for the rack, which enables a panel to be installed at a closely desired height and enables the panel height to be adjusted to avoid gaps between panels, which avoids the need for a vertical row of threaded holes in the strut, which allows the panel to lie flush with an exposed front face of the struts, and which provides a channel(s) through which wires can be extended. The rack is an extruded member with at least a front mounting portion and with a column portion that strengthens the strut against lateral buckling. The front mounting portion has walls forming a mounting cavity with a vertical front opening, the walls including flanges on laterally opposite sides of the vertical opening. This allows the use of a fastening assembly that includes a screw that projects rearwardly through a panel hole and through the vertical opening and that has a screw rear portion that is threadably connected to a nut. The nut has opposite ends that press against the opposite flanges, so when the screw is tightened it clamps the panel between the screw head and the front surface of the mount portion at the flanges. The column portion is formed by an integral longitudinally elongated strut portion that lies on a side of the mount portion that is opposite the opposite strut, to considerably increase the strut strength against buckling. The column portion preferably forms a forward projection that projects forward of the flanges by the thickness of a panel, to conceal the edge of a panel. The two struts of a rack are preferably identical, and the strut is preferably symmetric about a lateral mid plane. This provides a mount portion at the rear of the first strut which can pass wires, and which is used as the front mount portion of the second strut when a strut identical to the first one is turned 180° about its vertical axis.

Although particular embodiments of the invention have been described and illustrated herein, it is recognized that modifications and variations may readily occur to those skilled in the art, and consequently, it is intended that the claims be interpreted to cover such modifications and equivalents.

Claims

1. A rack with front and rear longitudinally spaced ends, for supporting panels with holes, which includes a pair of laterally spaced and parallel vertical struts and a plurality of beams that extend between said struts to fix the spacing of the struts, wherein:

each of said struts forms a front mount portion with cavity walls that form a mount cavity with a front that forms a vertical strip-shaped opening and that forms a pair of flanges on laterally opposite sides of said opening, said flanges forming rearwardly-facing flange surfaces at opposite sides of the front of the cavity;

a plurality of fastener assemblies that each fastens a location on one of said panels to said rack, each fastener assembly including a screw that extends through one of said panel holes and a nut that is threadably engaged with the screw, the nut lying in said cavity and having nut opposite ends that each presses forwardly against one of said flange surfaces;

each of said struts is of constant cross-section along its height and forms a column portion of increased thickness at a side of said mount portion that adds to the buckling resistance of the strut and that is integral with said front mount portion.

2. The rack described in claim 1 wherein:

each of said struts has a rear mount portion that lies behind said front mount portion and that forms a vertical channel with a vertical strip-shaped opening.

3. The rack described in claim 1 wherein:

said panels each have a predetermined thickness;

said column portion has a forward projection that lies laterally adjacent to said front mount portion and that projects forward of said front mount portion by a distance equal to the thickness of said panels.

4. The rack described in claim 1 wherein:

said pair of struts are identical in cross-section, with each strut having a predetermined longitudinal length and having a rear mount portion with cavity walls that form a rear mount cavity having a vertical strip-shaped rear opening and a pair of flanges on laterally opposite sides of said rear opening;

said front and rear mount portions of each strut are longitudinally spaced, and said column portion of each strut extends along the full longitudinal length of the strut and merges with walls of each mount portion;

said column portions of said pair of struts lie at laterally opposite sides of said rack, with said mount portions lying laterally between said column portions of said pair of struts.

5. The rack described in claim 4 wherein:

the column portion of each strut extends longitudinally forward and rearward of the mount portions of the strut, by distances that are each equal to the thickness of said panels.

6. The rack described in claim 1 wherein:

said mount cavity has a predetermined width rearward of said flanges, and said mount cavity has a rear cavity wall spaced longitudinally a predetermined distance rearward of said flanges;

each of said fastener assemblies includes a compression spring lying in said mount cavity behind said nut, with the rear cavity wall positioned so the spring is compressed.

7. The rack described in claim 1 wherein:

each of said struts has a rear mount portion that lies behind said front mount portion and that forms a vertical channel, with a recess between said front and rear mount portions, and with said column portion lying on one lateral side of said recess and with the other lateral side of the recess being open.

8. A strut that is useful to form one lateral side of a rack on which panels can be mounted comprising:

an elongated extrusion of constant cross-section along its length which forms a front mount means on which a panel can be mounted and which forms an integral column means on one lateral side of the mount means, said front mount means including walls forming a front cavity with a rear wall and side walls and with a front wall that includes laterally opposite flanges that extend toward each other and that leave a front cavity opening between said flanges.

9. The strut described in claim 8 including said rack, wherein said panel has a hole, and including:

a nut lying in said cavity, said nut having opposite ends lying against rear faces of said flanges;

a screw having a screw head lying forward of said panel and having a screw shank that extends through said cavity opening between flanges and that is threadably engaged with said nut, said screw clamping said panel against front faces of said flanges.

10. The strut described in claim 8 wherein:

said extrusion forms a rear mount means lying behind said front mount means, said rear mount means having a rear cavity with a front wall and side walls and with a rear wall that includes laterally opposite rear flanges that extend toward each other and that leaves a vertically-extending rear cavity opening between said rear flange.

11. The strut described in claim 8 including said rack, wherein said rack includes said strut at a first lateral side of the rack and a second strut element at an opposite second side of the rack;

said strut and said strut element are of identical shape and orientation if one of them is turned 180° about an axis, but on said rack the column means of the strut and strut element lie on internally opposite sides of the corresponding front mount means.