GB2345588A

GB2345588A - Surface box

Info

Publication number: GB2345588A
Application number: GB9900444A
Authority: GB
Inventors: Stephen Paley; John Trevelyan
Original assignee: Electrak International Ltd
Current assignee: Electrak International Ltd
Priority date: 1999-01-08
Filing date: 1999-01-08
Publication date: 2000-07-12
Anticipated expiration: 2019-01-08
Also published as: GB9900444D0; GB2345588B

Abstract

A surface box for insertion into an opening in a surface, for example a floor may be of the kind for providing electrical connections to an underfloor power distribution system. The surface box comprises a housing which forms a cavity into which the various electrical connections can be mounted, and a trim unit. The trim unit is intended to extend around the edges of the opening and is provided with connecting latches for connection to the housing. The latches interconnect with receiving elements mounted in the housing and the arrangement is such that the trim unit may be fitted to the housing simply by pushing the trim unit into the housing in the direction of the cavity. Once inserted into the housing the trim unit is locked in position by the latches. It may easily be unlocked from the housing for subsequent removal by simple manual manipulation of the latches, without the need for the use of tools.

Description

SURFACE BOX The present invention relates to surface boxes for inserting into an opening in a surface, and in particular to surface boxes with removable trim units.

Surface boxes are well known in the art for providing means for enabling electrical connectors, switches and the like to be located within an opening in a surface. An example well known in the art is for providing access to a plurality of three-pin sockets in an opening in a floor.

Most surface boxes comprise a housing and a trim unit. The housing is located in the opening in the surface and defines a cavity in which the desired electrical connectors or the like are located. The trim unit is located around the cavity and is usually fitted flush to the housing. The trim unit has the function of improving the appearance of the surface box and often provides means for fitting a cover to the surface box. In addition, it usually covers the join between the decorative floor covering and the edges of the opening.

It is often the case that a large number of surface boxes are fitted at the same time.

Therefore the time taken to connect the trim unit to the housing for all of the surface boxes is a significant factor in the operation. The time that it takes to connect a trim unit to a housing is dependent upon the ease of use of the connecting means, which in turn depends upon the number of tools required. Where a particular tool is required to connect a trim unit to a housing, this can be a limiting factor in the number of people performing the connecting operation at any one time. If the actual procedure for connecting the trim unit to the housing is complex, this will also increase the time taken to connect each trim unit to a housing, and increase the likelihood of error in the fitting operation.

In the case of floor boxes, the decorative floor covering, for example carpet, is often fitted before the trim units are connected. However, the housings are fitted to the underlying surface first. When the housings are fitted it is convenient to connect the trim units to the housings to prevent the trim units from being lost or damaged, for example. When the decorative floor covering is subsequently fitted it is therefore necessary to remove the trim units from the housings. Therefore, if the process of removing the trim units from the housings is particularly simple and requires no special tools, then a significant amount of time can be saved. Additionally, the thickness of the decorative floor coverings can vary considerably depending on their nature. It is therefore preferable that the connecting means between the trim unit and the housing is designed to accommodate different thicknesses of decorative floor coverings.

It is an object of the present invention to provide on surface box with an improved means of connecting a trim unit to a housing.

According to the present invention there is provided a surface box for insertion in an opening in a surface, comprising a housing, means for supporting the housing within the opening, a trim unit adapted to extend along at least one of the edges of the opening, and connecting means adapted to connect the trim unit to the housing, whereby said connecting means is operable lockingly to interconnect the trim unit and the housing by manual manipulation without the need for a tool.

Suitably, the connecting means is operable to interconnect the trim unit by relative movement between the two components; preferably, this relative movement takes place in a direction substantially perpendicular to said surface.

Preferably, the connecting means which allow the trim unit to be simply pushed into engagement with the housing comprise a first latch element on the housing and a second latch element on the trim unit, said latch elements being adapted to engage with each other on relative movement of the housing and the trim unit towards each other in a direction substantially perpendicular to said surface. The latch elements have a number of locking positions and allow the trim unit to be connected to the housing at a plurality of different positions. By providing a number of locking positions it is possible to accommodate varying thicknesses of any decorative coverings used.

Advantageously, the connecting means is also operable to disconnect the trim unit and the housing by manual manipulation without the need for a tool.

In order that the invention may be more fully understood, embodiments of the invention are now described below with reference to the accompanying drawings, in which Fig. 1 shows a perspective view of a trim unit and housing of a surface box for installation in the floor of a building, together with an opening in the floor into which the surface box may be inserted; Figs. 2a, 2b and 2c show different detailed views of a locking member of the trim unit; Figs. 3a, 3b, 3c and 3d show detailed views of a receiving element of the trim unit; Figs. 4a, 4b 4c and 4d show detailed views of a different embodiment of a receiving element; Fig. 5 shows a cross-sectional view of part of a trim unit with one locking member in the locking position and one locking member in the release position; Fig. 6 is a perspective view, partly in section, of a part of a trim unit and housing in a position for the trim unit to be secured to the housing; Fig. 7a shows a cross-sectional view of part of a trim unit connected to a housing, with the interposition of a thin decorative floor covering; and Fig. 7b shows a similar view of a trim unit connected to a housing, with the interposition of a thick decorative covering.

Referring to the drawings, Fig. 1 shows a surface box according to one embodiment of the invention. In use, the surface box is inserted into an opening 2 in a surface 1. The surface 1 is in this case the floor of a room, but it could be any other planar surface, for example a wall. The surface box comprises a housing 3 and a trim unit 4.

The housing 3 comprises a plurality of side walls 5; in this embodiment there are four side walls; and a base 6 which together define a cavity. In some embodiments the base 6 may be a separate element which is fitted to the housing. In use, various electrical connections and fittings, for example 3-pin sockets or telephone cable sockets, are located within the cavity. The opening 2 in the surface 1 is of substantially the same dimensions as the housing 3 so that the housing 3 can be inserted into the opening 2 and supported within the opening 2. The housing 3 is supported within the opening 2 by flanges 3a and may be fixed therein by any method known in the art. For further details of one such method reference is made herein to the applicants copending British patent application No. 9616708.5.

The trim unit 4 also comprises a plurality of side walls 9 of the same number of the housing 3. The trim unit 4 is of a size such that it can be inserted into the cavity defined by the housing 3 with the trim unit side walls 9 either in contact with, or in close proximity to, the housing side walls 5. Depending from at least one of the trim unit side walls 9 and extending into the cavity defined by the housing 3 is at least one enclosure 10 which houses one or more locking members 7. In the preferred embodiment two enclosures 10 depend from two opposite trim unit sidewalls 9 and each enclosure 10 extends from respective ends of the side walls 9 along the length of the side walls 9 such that a gap 11 is left between the closest end faces of the respective enclosures 10. In the preferred embodiment each enclosure houses a single locking member. The locking member will be described in more detail with reference to Figs. 2a, 2b, and 2c.

Each enclosure 10 has two windows formed therein, through which portions of the locking member protrude. The first window is in the end face of the enclosure 10 adjacent to the gap 11 between the two enclosures and the protruding portion of the locking member extends into the gap 11. The second window is in the face of the enclosure 10 which is adjacent to the base 6 of the housing 3 when the trim unit 4 is inserted into the housing 3 and the protruding portion of the locking member 7 protrudes at substantially 90 to the plane of the base 6.

The housing 3 further comprises a number of receiving portions 8 located in the base 6.

The number of receiving portions is equal to the number of locking members in the trim unit 4. Each receiving portion is positioned in the base so that when the trim unit 4 is inserted into the housing 3, the portions of the locking members 7 protruding from the second window of the enclosures 10 engage with the receiving portions 8. The receiving portions will be described in more detail with reference to Figs. 3a to 3d.

Figs. 2a to 2c shows various views of a locking member 7 in more detail. The locking member 7 comprises a locking arm 20, a lever arm 21, and a resilient element 22 all of which depend from a pivot portion 23. The pivot portion 23 is substantially cylindrical in shape with a curved surface and two planar end surfaces. The locking arm 20 and lever arm 21 each depend from the curved surface of the pivot portion 23 at substantially 90 to each other.

The locking arm 20 comprises a linear element which has a width substantially equal to, but not greater than, the width of the pivot portion 23 and a thickness less than the diameter of the pivot portion 23. On the surface of the locking arm 20 furthest from the lever arm 21 there is a latch element 45. Each latch element 45 comprises a plurality of angular ridges projecting from the surface and extending across the width of the locking arm 20. At the free end of the locking arm 20 the end surface is inclined at an angle of less than 90 from the linear axis of the locking arm 20.

The lever arm 21 also comprises a linear element having a width substantially equal to, but not greater than, the length of the pivot portion 23 and a thickness less than the diameter of the pivot portion 23. The linear element has two right angle bends in opposite directions to each other along its length such that the lever arm 21 has a"step" profile, as seen most clearly in Fig. 2a.

The resilient element 22 depends from the pivot portion 23 at a point between the locking arm 20 and the lever arm 21 and subtends an angle of less than 90 to either the locking arm 20 or the lever arm 21. The resilient element has a width substantially the same as, but not greater than, the width of the locking arm 20 and lever arm 21.

However, the thickness of the resilient element 22 is less than that of the locking arm 20 and lever arm 21 so that the resilient element 22 is elastically deformable. The length of the resilient element 22 is less than the length of the locking arm 20 or lever arm 21.

Extending from the lever arm is a further linear portion 28 and extending from the locking arm there is a second further linear portion 29. The two further linear portions 28,29 are arranged to be joined to each other at a point substantially opposite the resilient element 22. At the point where the two further linear elements 28,29 join, there is formed a movement limiting element 25. The movement limiting element 25 comprises a ridge extending across the width of the two further linear portions 28,29.

The ridge is substantially non-deformable.

The locking member 7 further comprises a tapered lug 24 depending from each of the end surfaces of the pivot portion 23. Each tapered lug 24 comprises a disc of diameter less than the diameter of the pivot portion 23 which depends from an end face of the pivot portion 23 such that the circumference of the disc and the end face of the pivot proportion are substantially concentric. Each tapered lug 24 further comprises an angled planar surface extending from a point or line of intersection between the tapered lug 24 and the end face of the pivot portion 23 to the face of the disc. When the locking member 7 is viewed from the direction of the arrow as shown in Fig. 2b, the angled planar surface appears at the top of the tapered lug 24. Figures 3a-3d show detailed views of the preferred embodiment of one of the receiving portions 8. Each receiving portion 8 comprises a substantially L shaped element 101. Depending from the foot of the L shaped element 101 and extending beyond the foot in the opposite direction thereto, is an abutment face 100. Depending from the abutment face is a latch element 44. The latch element 44 comprises a plurality of latching teeth, each of said teeth being an angular ridge of substantially the same profile as that of the latch element 45 of the locking member 7. Depending at substantially 90 from the abutment face 100 is a first planar element 102. The first planar element 102 is substantially parallel to the longest portion of the L shaped member 101 and is arranged spatially from the L shaped member 101 so that a slot 106 is formed there between. At the extremity of the surface of the L shaped member 101 which is closest to the first planar element 102, there is provided a retaining stud 105. Depending from the first planar element 103 and the abutment face 100 and at substantially right angles to both of them, there is a first supporting element 103. There is a second supporting element 104 depending from the two perpendicular parts of the L shaped member 101 in a similar manner.

In use, the receiving portion 8 according to this first embodiment of the present invention is inserted into an aperture in the base 6 of the housing 3 and slid into a further elongate aperture extending from the aperture in the base 6 of the housing 3.

The portion of the base 6 of the housing 3 adjacent to the elongate aperture is inserted into the slot 106 in the receiving portion 8 and the retaining stud 105 exerts a frictional force against the base 6 of the housing 3 to retain the receiving portion 8 in place.

Figs. 4a and 4b show detailed views of a second embodiment of one of the receiving portions 8. Each receiving portion 8'comprises four side walls 40 arranged to form a square or rectangle enclosing an aperture 43. Each side wall has a inner surface 41 adjacent to the aperture 43 and an outer surface 42. Depending from each side wall and at substantially 90 to the side wall, are flange portions 47. When viewed through a cross section of the receiving portion 8 the side walls 40 and the flange portions 47 form an L shape.

On the inner surface 41 of one of the side walls 40 is a latch element 44. The latch element 44 of the receiving portion comprises a plurality of angular ridges of substantially the same shape and profile as that of the latch element 45 of the locking member 7. On the outer surface 42 of at least one of the side walls 40 depends a further latch element 46. The further latch element 46 comprises a wedge-shaped portion and depends from the side walls 40 of the receiving portions 8'such that the thickness of the wedge-shaped portion is at a minimum the further from the flange portion 47 and increases to a maximum nearer to the flange portion, where the wedge-shaped portion has a planar surface at substantially 90 to the outer surface 42 of the side wall 40 and substantially parallel to the flange portions 47.

Figs. 4c and 4d show detailed views of a third embodiment of the receiving portion, wherein each receiving portion comprises three side walls 40 arranged at substantially 90 to each other and forming an opening 43'which corresponds to the aperture 43 of the receiving portion according to the first embodiment described above. Each side wall 40 has a flange portion 47 depending from it and an inner surface 41 and an outer surface 42 as described above with reference to Figs. 3a and 3b. On the inner surface 41 of one of the side walls is at least one latch element 44. The latch element 44 is as described above with reference to Figs. 3a and 3b. At least one other side walls 40 also has a further latch element 46 as described above with reference to Figs. 4a and 4b depending from it.

According to the second and third embodiments of the receiving portions 8'and 8", each receiving portion is inserted in to a corresponding aperture in the base 6 of the housing 3. The corresponding aperture in the base 6 in the housing has substantially the same dimensions as those defined by the outer surfaces 42 of the side walls 40 of the receiving portion 8, whereby when the receiving portion 8 is inserted in to the corresponding aperture in the base 6 of the housing 3 each further latch 46 depending from the side walls 40 of the receiving portion initially engage with the base 6. Further insertion of the receiving portion 8 can occur due to the elastic deformation of the side walls 40. Deformation of the side walls 40 continues until the full extent of the further latch 46 has passed through the corresponding aperture and beyond the base 6 of the housing 3. The receiving portion 8 is now prevented from being inserted further in to the corresponding aperture by the flange portions 47 which abut against one surface of the base 6 and is prevented from being extracted from the corresponding aperture by the planar surface of the further latch 46 which abuts against the opposite surface of the base 6 of the housing 3.

In a further embodiment, not shown, the receiving portions 8 may themselves comprise an aperture in the base 6 of the housing 3 and be integral to the base 6. In such an embodiment the latch element 44 comprises one of the edges of the base 6 adjacent to and within the aperture.

In either of the above described second or third embodiments of the receiving portions 8, the aperture 43'and opening 43'formed by the side walls 40 is sufficiently large enough to allow the locking arm 20 of a locking member 7 to be inserted therein and furthermore, large enough to allow the locking arm to move in to and out of engagement with a latch element 44.

Fig. 5 shows a cross sectional view of the trim unit 4 with two locking members 7 in place. The locking member 7 on the left hand side of Fig. 5 is shown in the locking position and the locking member 7 from the right hand side of Fig. 5 is shown in the release position. The tapered lugs 24 of each locking member 7 engage with respective recesses (not shown) formed within the enclosures 10. Engagement of the tapered lugs 24 in to the recesses is facilitated by the angled planar surface of the lugs 24.

Engagement of the lugs 24 in the recesses allow each locking member 7 to move rotationally about the axis of the pivot portion 23.

The resilient element 22 of each locking member 7 abuts against an inner surface of the enclosure 10 and urges the locking member 7 towards the locking position. The locking member is prevented from being urged beyond the locking position by the movement limiting element 25 which abuts against a stop block 12 within the enclosure 10. The locking element may be moved from the lock position to the release position by applying a force to the lever arm 21 in the direction of the arrow"A"shown on Fig. 5, whereby the locking member 7 rotates about the axis of the pivot portion 23. The rotational movement of the locking member is stopped when the lever arm 21 abuts against the stop block 12.

As the resilient element 22 already abuts against an inner surface of the enclosure 10 when the locking member 7 is in the locking position, it is prevented from moving rotationally with the locking member when it is moved to the release position and deforms elastically. The elastic deformation of the resilient element 22 when the locking member 7 is in the release position results in an increase in force with which the resilient element urges the locking member 7 towards the locking position, whereby the when the force applied to lever arm 21 is removed the locking member 7 returns to the locking position.

In use, the trim unit 4 is inserted into the cavity defined by the housing 3, in a direction perpendicular to the floor surface, as shown in Fig. 6. As the trim unit is inserted in to the cavity, the locking arms 20 of the locking member 7 engage with the receiving portions 8. Preferably there is no force being applied to the lever arms 21 of the locking member 7 and the locking members are in the locking position. The latch elements 44,45 of the receiving portions and the locking levers come into contact with each other.

However, as the trim unit 4 is further inserted into the cavity the resilient element 22 of the locking member 7 deforms sufficiently to allow the two latch elements of the respective receiving portion 8 and locking arm 20, to move over each other.

As the trim unit is inserted into the housing the two latch elements 44,45 sequentially engage in each one of the plurality of locking positions defined by the plurality of angular ridges. The trim unit 4 is continued to be inserted into the cavity defined by the housing 3 until the trim unit 4 comes into contact with either the surface 1 or any decorative covering 50 which has been placed over the surface. Where a decorative covering 50 has been applied over the surface 1 the number of locking positions which the latch elements 44,45 sequentially move into will be dependent upon the thickness of the decorative covering 50. Figure 7a shows the trim unit 4 connected to the housing 3 with a thin decorative covering 70 superimposed between the trim unit 4 and the housing 3. The locking arm 20 of the locking member 7 is engaged with the receiving portion 8 at a part of the receiving portion 8 which extends beyond the base 6 of the housing 3 in a direction away from the trim unit 4.

Figure 7b shows the trim unit 4 connected to the housing 3 with a thick decorative covering 72 in between. In this case, the locking arm 20 of the locking member 7 engages with the receiving portion 8 at a part of the receiving portion 8 which extends beyond the base 6 of the housing 3 in a direction towards the trim unit 4.

When the trim unit is fully inserted in to the cavity the resilient element 22 urges the locking members 7 fully into their locking position and the latch elements of the receiving portion 8 and locking arm 30 are fully engaged with each other. The angular ridges comprising the latch elements are shaped such that when the latch elements are engaged with each other, the locking arm 20 cannot move with respect to the receiving portion 8 in the direction that would result in the locking arm 20 being removed from the receiving portion. Therefore the trim unit 4 cannot be simply pulled out of the cavity of the housing 3.

It will be appreciated that the positioning and engagement of the trim unit can be preformed without the use of any tools in an extremely rapid and reliable manner, thus saving substantially in installation time while ensuring a secure interconnection between the two components.

To remove the trim unit from the housing, a force is applied to the lever arms 21 of the locking member 7 to move the locking members in to the release position, as described with reference to Fig. 5. In the release position the locking arms 20 of the locking members move away from the latch elements 45 of the receiving portions 8, such that the latch elements 45 with the locking arms 20 disengage from the latch elements 44 of the receiving portions 8. With the locking members 7 held in a release position, the trim unit 4 can be easily extracted from the cavity with the housing 3.

The various embodiments for the present invention described above are given by way of illustrative examples only and are not intended to limit the scope of invention in any manner.

Claims

CLAIMS 1. A surface box for insertion in an opening in a surface, comprising a housing, means for supporting the housing within the opening, a trim unit adapted to extend along at least one of the edges of the opening, and connecting means adapted to connect the trim unit to the housing, whereby said connecting means is operable lockingly to interconnect the trim unit and the housing by manual manipulation without the need for a tool.
2. A surface box as claimed in Claim 1, wherein the locking means is operable to interconnect the trim unit and the housing by means of relative movement therebetween.
3. A surface box as claimed in Claim 2, wherein the locking means is operable to interconnect the trim unit and the housing by relative movement between the trim unit and the housing in a direction substantially at perpendicular to said surface.
4. A surface box as claimed in any preceding claim, wherein said connecting means is operable to interconnect the trim unit and the housing at a plurality of different relative positions.
5. A surface box as claimed in any preceeding claim, wherein the connecting means is operable to disconnect the trim unit and the housing by manual manipulation without the need for a tool.
6. A surface box as claimed in any preceding claim, wherein said connecting means comprises a first latch element on the housing and a second latch element on the trim unit, said latch elements being adapted to engage with each other on relative movement of the housing and the trim unit towards each other in a direction substantially perpendicular to said surface.
7. A surface box as claimed in Claim 6, wherein one of said latch elements comprises a fixed abutment, while the other comprises a latch member biased into engagement with said abutment.
8. A surface box as claimed in Claim 7, wherein said latch member comprises a plurality of latching teeth each defining a locking position.
9. A surface box as claimed in Claim 8, wherein said latch member, said spring means and said unlocking element are moulded integrally from resilient plastics material. lu, A surface box as claimed in Claim 9, wherein a plurality of said latch elements are carried by said trim unit and are adapted to engage with corresponding fixed abutments on said housing.

A surface box constructed and arranged substantially as hereinbefore described, with reference to, and as illustrated in Figs. 1 to 7 of the accompanying drawings.

9. A surface box as claimed in Claim 8, wherein said latch member comprises spring means for biassing said latch element into a locking position; and an unlocking element for moving said latch member away from said locking position against the action of said spring means.

10. A surface box as claimed in Claim 9, wherein said latch member, said spring means and said unlocking element are moulded integrally from resilient plastics material.

11. A surface box as claimed in Claim 10, wherein a plurality of said latch elements are carried by said trim unit and are adapted to engage with corresponding fixed abutments on said housing.

12. A surface box constructed and arranged substantially as hereinbefore described, with reference to, and as illustrated in Figs. 1 to 7 of the accompanying drawings.

Amendments to the claims have been filed as follows CLAIMS 1. A surface box for insertion in an opening in a surface, comprising a housing, means for supporting the housing within the opening, a trim unit adapted to extend along at least one of the edges of the opening, and connecting means adapted to connect the trim unit to the housing, whereby said connecting means is operable both to lockingly interconnect and to disconnect the trim unit and the housing by manual manipulation without the need for a tool.

2. A surface box as claimed in Claim 1, wherein the locking means is operable to interconnect the trim unit and the housing by means of relative movement therebetween.

3. A surface box as claimed in Claim 2, wherein the locking means is operable to interconnect the trim unit and the housing by relative movement between the trim unit and the housing in a direction substantially at perpendicular to said surface.

4. A surface box as claimed in any preceding claim, wherein said connecting means is operable to interconnect the trim unit and the housing at a plurality of different relative positions.

5. A surface box as claimed in any preceding claim, wherein said connecting means comprises a first latch element on the housing and a second latch element on the trim unit, said latch elements being adapted to engage with each other on relative movement of the housing and the trim unit towards each other in a direction substantially perpendicular to said surface.

6. A surface box as claimed in Claim 5, wherein one of said latch elements comprises a fixed abutment, while the other comprises a latch member biased into engagement with said abutment.

7-A surface box as claimed in Claim 6, wherein said latch member comprises a plurality of latching teeth each defining a locking position.

8 A surface box as claimed in Claim 7, wherein said latch member comprises spring means for biassing said latch element into a locking position; and an unlocking element for moving said latch member away from said locking position against the action of said spring means.