This invention relates to a security unit particularly for reducing the frequency of theft of relatively valuable items of office equipment such as personal computers, printers, fax machines, C.A.D. machines etc. It will be appreciated that in most office situations such valuable items normally remain exposed overnight or over a week-end, because of the difficulty in removing these items to a safer storage area and then retrieving these items at the start of the next working day, and repeated losses in buildings prone to theft have resulted in substantial increases in insurance premiums or even an inability to secure insurance cover.

A basic object of the present invention is to provide an office security unit which renders considerably more difficult the theft of valuable items of equipment.

According to the present invention, there is provided an office security unit comprising:

(i) a sheet metal casing including at least two spaced-apart sidewalls; (ii) a back wall interconnecting the sidewalls;

(iii) an openable or removable top wall; (iv) a front wall;

(v) a shelf located within the casing on which shelf a valuable item(s) of office equipment is adapted to be seated;

(vi) means to elevate the shelf from a lower, storage position - in which the item(s) is wholly within the

casing, is obscured, and is rendered secure by closure or replacement of the top wall and the front wall - to an upper, usable position in which, with the top wall or front wall opened or removed, the then elevated shelf presents the item(s) at a suitable working height for the user; and

(vii) means to affect controlled descent of the shelf from its upper position to its lower position.

Thus, with the office security unit in accordance with the invention, the item of equipment is securely stored overnight out of sight and consequently a prospective thief is uncertain as to the content, if any, of the office security unit and furthermore must spend additional time in the office premises attempting to gain access to the interior of the office security unit. Consequently, the office security unit in accordance with the invention is attractive not only to organisations whose premises are susceptible to theft, but also to insurers.

The sheet metal casing preferably also incorporates a rectangular base panel, connected to the sidewalls and also to the back wall. The base panel may possibly be provided with reinforcing strips or angle bars which may be apertured so that the office security unit may be screwed or bolted to a floor. Indeed, reinforcing strips or angle bars may be provided internally and/or externally of the casing, wherever deemed necessary. Although the front wall could be a fixed- position front wall, it is preferably openable or removable.

In accordance with a preferred embodiment, both the top wall and the front wall are provided by a single roller

shutter comprising a plurality of articulated laths with their ends slidably located in guide tracks extending along inside faces of the sidewalls. The shutter may be coiled into a roll in the "open" condition of the unit, or, as is preferred is located down the inside of the backwall in the "open" condition of the unit with the guide track thus being generally of inverted "U"-shape. Although the shutter could be motorised, its relatively small size and weight, particularly if of aluminium alloy, is such that it may be, without difficulty, deployed manually. In its closed, deployed position, the roller shutter may be secured by a padlock etc., passing through a hasp or other aperture. Preferably however, the terminal lath incorporates a key- operated, rotary lock connected to a pair of opposed shoot bolts to engage apertures in the sidewalls.

Preferably, the inside surfaces of the sidewalls are also provided with one, or a pair, of vertically extending guideways for elevation and descent of the shelf in a horizontal condition. Thus, two spaced-apart, hollow guideways may be provided, with lateral edges of the shelf provided with slide shoes or rollers trapped in the guideways. Alternatively, one tubular guideway may be provided at each slidable eye or bearing ring or sleeve surrounding the tubular guideway. The means to elevate the shelf may be a manually operated means or a powered means. A manually operated means may advantageously incorporate weight-balancing means, preferably in the form of adjustable, springs and/or gas

struts, with a view to having the shelf, and the items carried thereby, rise slowly and automatically, or with minimum hand assistance upon release, yet capable of being pushed down, by hand, into its storage position with relative ease. An alternative manually or semi-manually operable means could include a hand or foot operated hydraulic or pneumatic jack, possibly with an interposed scissor mechanism or chain and sprocket arrangement etc.

However, with any manual or semi-manual arrangement, it is preferred to provide means to latch the shelf in its lower position, i.e. against the action of one, two or four gas struts, and also to provide means to latch the shelf in its upper position, or preferably in a selected one of several upper positions. Alternatively, a powered elevation means using an electric motor may be employed. In detail, the powered means to elevate the shelf preferably comprises a motor and axle located inside the casing e.g. bridging the inside surfaces of the sidewalls and adjacent the rear wall, preferably with a hoisting cable adjacent each sidewall, passing over a pulley located towards the top of each sidewall and attached to the shelf. As an electrical supply would normally be available for powering the item of office equipment, there is no difficulty in providing power to an electric motor to drive the axle.

The means to effect controlled lowering of the shelf, may be the same gas spring(s) as used to elevate the shelf, with the arrangement being for the shelf to descend basically

under its own weight and that of the item(s) that it carries plus minimum hand assistance. Alternatively, the means to effect controlled descent may be a friction or other brake device, or a fluid dashpot device. If, as would frequently be the case, a VDU monitor is located on the shelf, then in accordance with another preferred feature, a secondary, lower shelf is provided to carry the associated processor, with both shelves being raisable and lowerable together. In this case, the secondary shelf is preferably a pull-out shelf, on which a keyboard etc., may be located. The pull-out shelf may be attached to pull-out slide means by toggles or levers to provide for keyboard height adjustment and/or tilting facility.

Underslung from the shelf or shelves, and raisable and lowerable with the shelf or shelves, may be a generally "U"- shaped housing for another item of office equipment of value such as a computer processor.

Static shelves, either permanently exposed or concealable may be provided externally of one or both sidewalls for low value items such as paper. Concealment may be effected by extending the roller shutter beyond inner sidewalls to one, or two, outer sidewalls. Alternatively, the static shelves at one or both sides may be provided with an individual roller shutter. It will be appreciated that the office security unit in accordance with the invention may be of modular construction so that other required items of office furniture etc., may be attached, or butted, to one or both sidewalls of

the casing .

The invention will now be described in greater detail, by way of example, with reference to the accompanying drawings, in which:- Figure 1 is a perspective view of a first embodiment of office security unit in accordance with the invention in its closed, secure condition;

Figure 2 shows the unit of Figure 1 in its open condition but with the shelves in their lower position; Figure 3 corresponds to Figure 2 but shows the shelves moved to their upper position with the lower, secondary shelf in its pulled-out position;

Figure 4 details a manner of adjustably attaching the lower, secondary shelf to the primary, upper shelf. Figure 5 details one shelf raising and lowering means; and

Figure 6 corresponds to Figure 1 but shows a second embodiment of office security unit with an alternative shelf raising and lowering means. In the drawings is shown an office security unit 1 comprising a sheet metal casing 2 including a pair of spaced- apart, rectangular sidewalls 3, 4, and a rectangular backwall

5 and a rectangular base panel 6 interconnecting the sidewalls

3, 4. An openable top wall 7, and an openable front wall 8 are constituted by a roller shutter 9. A primary shelf 10 is located within the casing and, as illustrated in Figures 2 and

3, is adapted to carry a printer 11 and a monitor 12.

Beneath the primary shelf 10 is a secondary pull-out shelf 13

and so spaced from the underside of the primary shelf 10 that an industry-standard keyboard 14 may be permanently located on the secondary shelf 13, as can be seen in Figures 2 and 3, with the height of the top wall 7 and hence the height of the secondary shelf 13 being such that the knees of the operator can be comfortably located beneath the secondary shelf 13. Underslung from the shelf 10 is a "U"-shaped housing 15 of dimensions such that it can accommodate a range of industry- standard computer processors 16. The primary shelf 10, and with it the secondary shelf

13 and housing 15, are elevatable from the lower, storage position of figure 2, to the upper, operational position of figure 3, along a pair of spaced-apart, vertically extending guide tracks 17 secured to the insides of the sidewalls 3, 4. As illustrated in Figure 5, between the tracks 17 a hoisting cable 18 extends secured at one end to the shelf, passing over a pulley 19 mounted on a pivot secured to the inside of the sidewalls 3, 4, and being wound onto a motor driven axle (not shown) extending across the insides of the sidewalls 3, 4. The inside of each sidewall 3, 4, also carries an inverted "U"-shaped guide track 20 slidably engageable by the ends of a plurality of articulated laths 21 from which the roller shutter 9 is made up, and, as can be seen in Figure 2, in the "open" condition of the unit 1 , the laths 21 are located down the inside of the backwall. With the laths 21 of aluminium alloy, a roller shutter 9 of relatively small size and weight results such that it may be, without difficulty, deployed manually and for which purpose is

provided with finger grips 22, while its terminal lath 21 is provided with "L"-shaped strips 23 to engage a strip 24 interconnecting the sidewalls 3, 4, and the backwall 5 to determine the maximum opening of the roller shutter 9. The lower lath also incorporates a key operated rotary lock 25 connected to two opposed shoot bolts 26, ends of which are adapted, in the locked position, to engage apertures 27 provided in an angled corner member 28 at the junction between each sidewall 3, 4, and the base panel 6. The top wall 7 is extended at each side by two fixed wings 29, while, in the embodiment of Figure 1 , an array of open shelves 30 is provided between the outside of each sidewall 3, 4 and supporting struts 31 extending to a floor beam 32.

As illustrated in Figure 4, the height and angle of the secondary shelf 13 and hence the keyboard 14 are adjustable by providing, at each side, links 33 pivotally attached at one end to a slider 34 via a pivot 35 with a thumb locking screw 36, and at the other end to the shelf 13 via a pivot 37 with a thumb locking screw 38, various positions of adjustment being illustrated by way of example in chain-dotted line in Figure 4.

The office security unit illustrated in Figure 6 has an array of concealable shelves 30 with the roller shutter 9 suitably extended, or with each array of shelves 30 provided with individual roller shutters, so that this embodiment has inner sidewalls 3, 4 and outer sidewalls 39, 40. Also illustrated in Figure 6 is the means for elevating and for controlled descent, of the shelf 10 etc., in the form of a gas

strut 41 located between the pair of hollow or slotted guide tracks 17.