Sheet metal part for use in a housing for accommodating devices such as electrical, electronic and optical devices

Abstract

A sheet metal part for use in housing for accommodating devices such as electrical, electronic and optical devices is described. The sheet metal part comprises a penetrable opening through which the shank of a screw may be provided to bring the penetrable opening from an unpenetrated state to a penetrated state. The penetrable opening in the unpenetrated state is covered by an airtight coating layer, has a central area configured to accommodate a threaded shank of the screw and a lug extending radially outward from the central area over some distance, and the lug of the penetrable opening is configured to be bent back with the central area without coming loose from the sheet metal part when the penetrable opening is brought in the penetrated state by the shank of the screw.

Claims

1. A sheet metal part for use in a housing for accommodating devices, the sheet metal part comprising: a penetrable opening that comprises an area in the metal sheet part that has been weakened by having weakened boundaries, through which a threaded shank of a screw may be provided to bring the penetrable opening from an unpenetrated state to a penetrated state in order to mechanically and/or electrically connect a device or other part to the sheet metal part, wherein the penetrable opening being in a closed and unpenetrated state is covered by an airtight coating layer, and includes a central area of sheet metal in the plane of the sheet metal part configured to accommodate the threaded shank of the screw, and a lug in the plane of the sheet metal part extending radially outward from the central area over a distance, and wherein the lug of the penetrable opening is configured to be bent back around its connection with the sheet metal part together with the central area while remaining attached to the sheet metal part when the penetrable opening is brought in an open and penetrated state by the threaded shank of the screw.

2. The sheet metal part according to claim 1, wherein the airtight coating layer is provided at one or both sides of the sheet metal part.

3. The sheet metal part according to claim 1, wherein the central area is circular.

4. The sheet metal part according to claim 1, wherein the penetrable opening extends over part of a thickness of the sheet metal part or extends over the complete thickness of the sheet metal part.

5. The sheet metal part according to claim 1, wherein the airtight coating layer has a thickness and the penetrable opening in the unpenetrated state extends over the thickness of the sheet metal part and, optionally, over part of the thickness of the airtight coating layer.

6. The sheet metal part according to claim 1, wherein the airtight coating layer comprises a coating layer selected from a powder coating layer, a wet paint coating layer, a low-emissivity coating layer, an Electro-coating layer, a hot dipped galvanizing layer, a zinc coating layer, and/or a plastic dip coating layer.

7. The sheet metal part according to claim 1, wherein the lug extends radially outward from the central area over a distance of at least a diameter of the central area of the penetrable opening.

8. The sheet metal part according to claim 1, wherein the penetrable opening comprises one lug only.

9. The sheet metal part according to claim 1, wherein the lug has rounded edges.

10. The sheet metal part according to claim 1, wherein the lug is shaped such that the penetrable opening has a shape of a tennis racket and/or has a drop-like shape.

11. The sheet metal part according to claim 1, wherein the penetrable opening has been provided in the sheet metal part by laser cutting the boundaries of the weakened area to weaken the boundaries by a reduced thickness or by being cut through the complete thickness of the sheet metal part and obtain a flush outer surface between the penetrable opening and other parts of the sheet metal part, and/or by punching the weakened area with a punching tool that has a shape of the area defining the penetrable opening and weaken the boundaries by deforming these boundaries out of a plane of the sheet metal part.

12. The sheet metal part according to claim 1, wherein the lug of the penetrable opening is configured to be bent back plastically upon tightening the screw.

13. The sheet metal part according to claim 1, wherein the sheet metal part comprises a plurality of the penetrable openings arranged along a side edge of the sheet metal part.

14. The sheet metal part according to claim 1, wherein a wall thickness of the sheet metal part does not exceed 3 mm.

15. An assembly of a sheet metal part according to claim 1 and a device or other part connected thereto, the connection being provided by a screw with a head from which a shank emanates that is provided through the penetrable opening.

16. The assembly according to claim 15, wherein the sheet metal part comprises a protective electrically insulating layer on a side facing a head of the screw to be provided through the penetrable opening, and the head is at a shank side thereof provided with a cutting edge that cuts through the electrically insulating layer when tightening the screw, thereby providing an electrical connection between the screw and the sheet metal part to bring them to the same voltage level or for grounding purposes.

17. The assembly according to claim 15, wherein the shank is received and tightened in a cavity of the device or other part.

18. A housing for accommodating devices, the housing comprising at least one sheet metal part according to the assembly in accordance with claim 15.

19. A housing for accommodating devices, the housing comprising at least one sheet metal part according to claim 1.

20. The housing according to claim 18, wherein the sheet metal part comprises a wall of the housing, selected from an upstanding front, back or corridor wall, a floor wall or a roof wall of the housing.

Description

BRIEF DESCRIPTION OF THE FIGURES

(1) The invention will now be further elucidated on the basis of several non-limitative embodiments, as shown in the attached schematic figures. In the figures:

(2) FIG. 1 represents a perspective view of a housing or rack in which the invention may be applicable;

(3) FIG. 2 represents a detail of the rack shown in FIG. 1;

(4) FIG. 3A represents a schematic top view of a sheet metal part provided with a penetrable opening according to an embodiment of the invention;

(5) FIG. 3B represents a schematic side view of the sheet metal part of FIG. 3A according to an embodiment of the invention;

(6) FIG. 4 represents a schematic top view of a sheet metal part provided with a penetrable opening according to another embodiment of the invention;

(7) FIG. 5 represents a schematic top view of a sheet metal part provided with a penetrable opening according to yet another embodiment of the invention;

(8) FIG. 6A represents a schematic back view of a thin sheet metal part comprising an opening according to an embodiment of the invention in a closed (left), a used (middle) and an open state (right); and

(9) FIG. 6B finally represents a schematic front view of the thin sheet metal part of FIG. 6A in a closed (left), a used (middle) and an open state (right).

DESCRIPTION OF EXEMPLARY EMBODIMENTS

(10) Referring to FIG. 1, a rack 1 for accommodating devices such as electrical, electronic and optical equipment (not shown) according to an embodiment of the invention is shown. The rack comprises a rectangular floor 10 comprising four interconnected floor frame members 10a that extend between four floor corner elements 10b. Likewise, a rectangular roof 11 is provided, which comprises four interconnected roof frame members 11a that extend between four roof corner elements 11b. The floor 10 and roof 11 are held at a vertical distance 13 from each other by vertically extending side frame members 12, each side frame member 12 being provided between a floor corner element 10b and a roof corner element 11b. The frame members 10a, 11a and 12, and the corner elements (10b, 11b) together form a load bearing structure for accommodating equipment.

(11) The roof 11 in the embodiment shown is provided with three contiguous roof plates 11c made from a thin sheet metal, preferably steel. The sheet metal plates 11c have a thickness of 1.0 mm, but may have another thickness. In the embodiment shown in FIG. 1, two vertically oriented mounting rails 14 are provided in between each pair of side frame members 12, at least in two side planes 15 of the rack 1. Each mounting rail 14 is at an end thereof connected to a floor frame member 10a, and a roof frame member 11a, according to known practice. The 19 inch mounting rails 14 extend parallel to each other at a mutual standardized distance 16 of typically 17.7 inches. Each mounting rail 14 is further provided with a plurality of square openings 14a, extending along a longitudinal direction 14b of each mounting rail 14, and provided at equal height between mounting rails 14. Standardized, suitable equipment may be provided with fixation lips to be connected to the openings 14a, for instance by screws. In this way, multiple units of equipment (not shown) may be suspended on top of each other in the rack 1. The mounting rails 14 may be provided with other openings 14c for the same purpose, or for connecting to auxiliary parts of the rack 1, such as stiffening brackets, side walls (not shown) and the like. The rack 1 may, apart from the roof plates 11c that together form a roof wall part, be provided with other wall parts, such as side wall parts 17 or floor wall parts 18 to form a substantially closed cabinet. Surfaces of the roof plates 11c may be provided with a protective electrically insulating layer, such as a powder coating layer 111. Such a layer 111 protects the roof plates 11c but, on the other hand, electrically insulates the roof plates 11c, which may not be desirable for grounding purposes.

(12) Referring now to FIG. 2, a detail of a floor corner of the rack 1 is schematically shown. As shown, sheet metal parts such as side wall parts 17 may be provided with a plurality of openings 3. The openings 3 are shown as open, but according to the invention qualify to be embodied as penetrable openings 5 in accordance with embodiments of the invention. Possible shapes of these penetrable openings 5 will be elucidated further below, for instance with reference to FIGS. 3, 4 and 5.

(13) According to the invention, and for instance shown in the embodiment of FIGS. 6A and 6B, the sheet metal part in the form of wall part 17 comprises a penetrable opening 5 through which the shank 41 of a screw 4 may be provided to bring the penetrable opening 5 from an unpenetrated state (left side of FIGS. 6A and 6B, referred to as closed, before use) to a penetrated state (middle of FIGS. 6A and 6B, referred to as used) in order to mechanically and/or electrically connect a device or other part to the wall part 17. As shown, the penetrable opening 5 in the unpenetrated state is covered by an airtight coating layer 19 which closes off the underlying opening. The right side of FIGS. 6A and 6B, referred to as open, after removal of screw shows the penetrable opening 5 as an open opening 3, resulting from removing the screw 4 from the penetrable opening 5 in the penetrated state.

(14) Please note that the states referred to as closed, before use (left) and used (middle) provide airtightness to the wall part 17, whereas the state referred to as open, after removal of screw does not.

(15) To make the connection, any suitable screw 4 may comprise a head such as a panhead head 40 from which a threaded shank 41 emanates. The head 40 may be provided with a recess 42 for receiving a screw driver. The head 40 may at a shank side thereof be provided with a cutting edge (not shown) that cuts through the airtight coating layer 19, that for this purpose is also electrically insulating, when tightening the screw 4. This provides an electrical connection between the screw 4 and the wall part 17, for instance to bring these parts to the same voltage or for grounding purposes.

(16) An embodiment of a penetrable opening 5 is schematically shown in FIGS. 3A (top view) and 3B (side view). The penetrable opening 5 in the unpenetrated state is covered by an airtight coating layer 19 and further is defined by a central circular area 50 configured to accommodate the threaded shank 41 of the screw 4. A lug 51 is seen to extend in a radial direction 52 outward from the central area 50 over some distance 53, which in the embodiment shown is about 3.8 mm. The lug is shaped such that the penetrable opening 5 has a shape of a tennis racket. The central area has a diameter 54 of about 3.15 mm. As shown in FIG. 3B, the penetrable opening 5 is made by punching the wall part 17 or other sheet metal part with a punching tool to deform the wall part 17 in the shape of the penetrable opening 5. This deformed wall part is also shown in FIGS. 6A and 6B (left) and the boundaries thereof are weakened and will tend to break easily when a screw 4 is inserted in the penetrable opening 5. When the shank 41 of the screw 4 penetrates the central area 50, this central area 50 will be moved together with the lug 51 to which it remains connected. This situation is for instance shown in the middle of FIGS. 6A and 6B. In this process, the lug 51 of the penetrable opening 5 is bent back around its connection with the rest of the sheet metal part 17 together with the central area 50 without coming loose from the sheet metal part 17. The connection between the lug 51 and the rest of the sheet metal part 17 remains in place. As shown at the right of FIG. 6B, after removal of the screw there remains an opening 3 which has the shape of the penetrable opening 5 comprising an open circular central area 30 and an open lug shape 31. The lug 51 and moved central part 50 may remain attached to the sheet metal part 17, as shown at the right of FIG. 6A, but may also be removed with a tool.

(17) Other embodiments of the penetrable opening 5 are shown in FIGS. 4 and 5. These embodiments were made by laser cutting boundaries of the penetrable opening 5 to form weakened areas in the sheet metal part 17. The weakened areas will preferentially break along the boundaries when a screw 4 is inserted into the penetrable opening 5.

(18) The embodiment of FIG. 4 shows a number of circular penetrable openings 5 comprising round holes attached to the rest of the sheet metal part 17 through ribs 55, made by laser cutting. Embodiments having to diametrically opposed ribs tend to need some force to push it out. Also, round parts may come loose from the sheet metal part 17 more easily, potentially leaving debris.

(19) The embodiment of FIG. 5 shows a number of improved penetrable openings 5 having a lug 51 that is shaped such that the penetrable openings 5 have a drop-like shape, made by laser cutting as well. This embodiment may show a relatively weak connection between the lug 51 and the rest of the sheet metal part 17 (because it has less material around the screw 4 when inserted in the opening). This embodiment may be selected when it is desired to easily break off the penetrable opening material after insertion and removal of the screw 4.

(20) It will be apparent that many variations of the above described embodiments may be envisaged by one skilled in the art within the scope of the invention as determined by the attached claims.