Cabinet locking device

Abstract: A combined locking and anti-tilt device (1) for a cabinet, and a cabinet including such a locking and anti-tilt device, having a plurality of drawers (3) mounted so as to be slidable out of the cabinet, comprising a guide, and, slidably mounted within the guide, a plurality of block units (7), a part (9) of each block unit (7) projecting to a position engageable by part (5) of an adjacent drawer (3), opening of a drawer (3) causing movement of an adjacent block unit (7) in a direction towards a first end of the guide, the length of the guide within which the block units (7) may slide being limited such that the extent of movement of the block units (7) is limited, and a lock mechanism comprising a locking member (11) movable between a locked position and an unlocked position, is characterised in that the locking mechanism also comprises an elongate locking element (13) extending from the first end of the guide to at least the region of the locking member (11); the locking element (13) is secured to the first block unit (15) closest to the first end of the guide but arranged for relative movement with respect to the other block units (7); and the lock element (13) includes lock engagement means (45) arranged such that in the locked position of the locking member (11), movement of the first block (15) towards the first end of the guide causes the lock engagement means (45) of the lock element (13) to engage against the locking member (11) thus limiting movement of the first block (15).

Description: Field of the Invention The present invention relates to a device for locking a cabinet having a plurality of drawers, the device also serving as an anti-tilt mechanism for the cabinet. The invention is applicable with particular advantage to tall cabinets. In the following specification the term "cabinet" will be used to describe filing cabinets and other items of furniture within which there are mounted drawers for access or use. They include domestic furniture, office cabinets, laboratory furniture and kitchen furniture and indeed any item of furniture having a plurality of drawers. The furniture does not need to be enclosed. Open racking can be fitted with units that slide out and the invention can be equally applied in this case. The term "drawer" will be used in its broadest sense to mean a thing capable of being drawn out which apart from encompassing a standard slidable box also includes shelves, trays and frames from which files can be suspended. Cabinets often have a plurality of drawers which are fixed to the cabinet and when slid out remain supported by it cantilevered out beyond the base of the cabinet. If several of the drawers are withdrawn simultaneously and are heavy or carry weight, for example, those drawers full of office files, there is a serious risk that the cabinet may tilt forward. A number of devices have been proposed which act as a safety device to limit the number of drawers which can be withdrawn at the same time. Indeed in some countries all office filing cabinets have to include such a safety device. One such device is described in GB Patent 2 095 322. This describes a safety device which comprises a guide extending up a wall of the cabinet and blocking elements for the drawers of the cabinet. The elements can be moved along the guide to release the drawer but limited free length on the guide restricts the number of drawers which can be released simultaneously, preferably to one only. In the example shown in the above patent, the blocks are movable manually up and down the guide which can sometimes prove cumbersome. The device described includes no means for locking all of the drawers in a closed position. A number of improvements to this design have attempted to use the movable blocks to lock all of the drawers closed. The majority of such mechanisms comprise a lock mounted at the top of the cabinet with a lock mechanism which blocks the top of the guide to prevent upward movement of any of the blocks. The disadvantage of such a system is that in a tall cabinet the lock can at times be inaccessible. Summary of the Invention According to the invention, there is provided a combined locking and anti-tilt device for a cabinet having a plurality of drawers mounted so as to be slidable out of the cabinet, comprising a guide, and, slidably mounted within the guide, a plurality of block units, a part of each block unit projecting to a position engageable by part of an adjacent drawer, opening of a drawer causing movement of an adjacent block unit in a direction towards a first end of the guide, the length of the guide within which the block units may slide being limited such that the extent of movement of the block units is limited, and a lock mechanism comprising a locking member movable between a locked position and an unlocked position, characterised in that the locking mechanism also comprises an elongate locking element extending from the first end of the guide to at least the region of the locking member; the locking element is secured to the first block unit closest to the first end of the guide but arranged for relative movement with respect to the other block units; and the lock element includes lock engagement means arranged such that in the locked position of the locking member, movement of the first block towards the first end of the guide causes the lock engagement means of the lock element to engage against the locking member thus limiting movement of the first block. Thus the locking member can be mounted at any point within the cabinet since the locking element extends from the region of the locking member to the end of the guide limiting movement of the end blocking unit and thus all of the blocking units and therefore preventing the removal of any of the drawers. The cabinet may be adapted to include vertical drawers such that the guide is horizontal across the floor of the cabinet. However, typically the cabinet is an upright cabinet with horizontal drawers so that the first end of the guide is uppermost. The cabinet may not include just drawers and thus the guide only has to extend in the region of the drawers. However, in many cases the guide extends the full length of the cabinet, and thus the invention is particularly advantageous when the cabinet is tall, since the lock can be positioned at any convenient height for the user. Preferably the locking mechanism includes a standard locking bar known in the art where rotation of a key in a lock causes movement in a transverse direction of a horizontal bar. Preferably the locking member is arranged such that when in its locked position, it can also engage the adjacent block unit for extra security. For example, the adjacent block may include a bore into which the locking member may extend when in its locked position. The elongate locking element has to be such that it does not impede the movement of the drawer. In one embodiment an elongate rod with a series of projections forming the lock engagement means can be used. Here the locking member comprises a locking rod extending transverse to the elongate rod which in its locked position engages across the locking element such that the projection bears against the lock mechanism to prevent any movement. In an alternative and preferred embodiment, the elongate locking element comprises an elongate plate which passes over the block units and includes at least one slot into which the lock member may extend when in its locked position. The edge of the slot forms the lock engagement means of the locking element which engages against the lock member to restrict the movement of the locking element with respect to the lock member. For ease of manufacture, the plate typically includes a plurality of such slots spaced along its length. In this way the same design of plate may be used in a variety of cabinets having locking mechanisms mounted at different positions. The locking element does not have to prevent movement of the block units, but simply to restrict the movement sufficiently to not allow opening of a drawer. A cabinet typically includes on each drawer a projecting elongate member with a tapered nose which engages against an adjacent block unit. Preferably the block units adjacent to the nose of each drawer extension have mounted upon them a roller which is the part engagable by part of the drawer such that opening of a single drawer automatically moves the block units above that drawer in a direction towards the first end of the guide in a smooth movement. In their raised position, such rollers block the movement of any other drawer projections. Preferably the block units are arranged such that rollers in adjacent pairs are positioned such that opening of a drawer causes engagement of part of the drawer between the rollers of the adjacent block units. This is especially useful when the part of the drawer which engages the rollers is the elongate member with a tapered nose. It will be readily appreciated by the skilled addressee of the specification that there are many different shapes, materials and forms of block units which could be used in the invention. Brief Description of the Drawings Two embodiments of combined locking and anti-tilt devices for cabinets will now be described, by way of example only, with reference to the accompanying drawings in which:- Figure 1 is a schematic perspective view of the first embodiment illustrating the opening of a drawer (with drawer assembly and cabinet side removed); Figure 2 is a schematic view of the device of Figure 1 illustrating the locking member in unlocked position; Figure 3 is a view similar to Figure 2 with the locking member in locked position; Figure 4 is an exploded view of the first system with the cabinet side removed; Figure 5 is a schematic section through a second embodiment of the invention. Description of the Preferred Embodiment A first example of a combined locking and anti-tilt device 1 for a cabinet (not shown) is illustrated schematically in Figures 1 to 4 of the accompanying drawings. The cabinet has a plurality of drawers 3 mounted so as to be slidable out of the cabinet. In the drawings the full drawer is not illustrated, purely the front of the drawer and the side rail 5 mounted upon the side of each drawer. The device includes a guide which in this case is channel shaped, upright, elongate and mounted at the side of the cabinet but is not shown in the drawings. Within the guide are slidable a plurality of block units 7. Each block unit is hollow and of U-shaped cross-section as can be seen more clearly in Figure 4. Part 9 of each block unit 7 projects to a position engagable by part 5 of an adjacent drawer 3. Opening of a drawer 3 causes movement of the adjacent block unit 7 in a direction towards the first end of the guide in this case in an upwards direction. The device also includes a locking mechanism comprising a locking member 11 movable from a locking position shown in Figure 3 to an unlocked position shown in Figure 2 and an elongate locking element 13 which extends from the region of the locking member 11 to the first end of the guide being secured to the first block unit 15 closest to the first end of the guide but arranged for relative movement with respect to the other block units 7. In the locked position of the locking member 11 movement of the first block 15 towards the first end of the guide causes the base of the locking slot 45 (the lock engagement means) of the locking element 13 to engage against the locking member 11 thus limiting movement of the first block 15. In this case the drawer side rail 5 includes a tapered nose 17 and each of the block units 7 has mounted upon it a roller 19 which forms the part 9 which projects into the path of the drawer. Each block unit 7 has only one roller 19 mounted thereon at one end. Rollers are arranged such that the rollers 19 of adjacent block unit 7 are in contact with one another when the block units 7 are in contact with one another. The opening of a drawer is illustrated in Figure 1. The drawer side rail 5 moves forward until the tapered nose 17 engages between the two adjacent rollers 9. Because no other drawer is open, there is enough room within the guide for the block unit 7 above the side rail 5 to be able to move in an upwards direction. The rollers 19 facilitate smooth automatic movement upwards. This movement upwards means that the side rail 21 below the open drawer cannot be pulled outwards since this would cause upward movement of blocks 23,25 where block 25 cannot move upwards since its roller 27 is again engaged against side rail 5. This applies to any drawer mounted below the open drawer. The side rail 29 above the open drawer cannot be moved forwards since its nose 31 would bear against roller 33 rather than between two rollers so that no further forward movement is allowed. The elongate locking element comprises an elongate ladder strip 35 coupled to projecting flanges 37 for locating the ladder strip 35. This is secured to the first block 15 through a bolt (not shown) passing through bores 39,41 to ensure that relative movement between these two is not permitted. The ladder strip 35 lies over the front face of the blocks 7 and includes a plurality of elongate slots 43 through which rollers 19 may pass. When in the position shown in Figure 1 a drawer is open, the plate moves upwards with the blocks. The plate also includes a plurality of locking slots 45 only one of which is used as shown in Figures 2 and 3. The locking member 11 is coupled to a locking mechanism which ensures that, in its locking position, the horizontal bar 11 moves such that its end 47 engages in locking slot 45. By doing this relative movement between locking member 11 and the elongate member 13 is in this case prevented. This means that movement of the first block 15 is prevented and thus this locks all of the blocks beneath it. This effectively ensures that none of the drawers can be opened. In an alternative embodiment illustrated in Figure 5, each of the blocks 51 is of more solid construction and has mounted upon it two rollers 53,55. The mechanism for opening and closing the drawers however is similar to that described in connection with Figures 1 to 4 in that the tapered nose 57 of a drawer side rail 59 engages between two adjacent rollers when a drawer is to be opened. Each of the block members 51 includes a central bore 61 into which may be engaged locking bar 63 which prevents movement of the engaged block and any blocks beneath but still allows freedom of movement of any upper blocks. An elongate locking element 65 is illustrated schematically in a dotted line. The top end 67 is affixed to the uppermost block and projections 69 are positioned such that on engagement of the locking bar 63 upward movement of the uppermost block would cause projection 69 to bear against locking bar 63 so that the upward movement is limited. It will be appreciated that the invention is applicable to systems where the guide will be arranged horizontally and the blocks move horizontally but that the system would need to include means to return the block units to their original positions on closure of a drawer.

Claims: A combined locking and anti-tilt device (1) for a cabinet having a plurality of drawers (3) mounted so as to be slidable out of the cabinet, comprising a guide, and, slidably mounted within the guide, a plurality of block units (7), a part (9) of each block unit (7) projecting to a position engageable by part (5) of an adjacent drawer (3), opening of a drawer (3) causing movement of an adjacent block unit (7) in a direction towards a first end of the guide, the length of the guide within which the block units (7) may slide being limited such that the extent of movement of the block units (7) is limited, and a lock mechanism comprising a locking member (11) movable between a locked position and an unlocked position, characterised in that the locking mechanism also comprises an elongate locking element (13) extending from the first end of the guide to at least the region of the locking member (11); the locking element (13) is secured to the first block unit (15) closest to the first end of the guide but arranged for relative movement with respect to the other block units (7); and the lock element (13) includes lock engagement means (45) arranged such that in the locked position of the locking member (11), movement of the first block (15) towards the first end of the guide causes the lock engagement means (45) of the lock element (13) to engage against the locking member (11) thus limiting movement of the first block (15). A combined locking and anti-tilt device (1) according to claim 1, further characterised in that the locking member (11) is arranged such that when in its locked position, it can also engage the adjacent block unit (7). A combined locking and anti-tilt device (1) according to claim 1 or 2, further characterised in that the elongate locking element comprises an elongate rod (65); the lock engagement means comprises a projection (69); and the locking member comprises a locking rod (63) extending transverse to the elongate rod (65) which in its locked position extends across the elongate rod (65) such that the projection (69) bears against the locking rod (63) to limit movement of the first block. A combined locking and anti-tilt device (1) according to claim 1 or 2, further characterised in that, the elongate locking element comprises an elongate plate (35) which passes over the block units (7), and which includes at least one slot into which the locking member (11) extends in its locked position, the edge of the slot forming the lock engagement means (45). A combined locking and anti-tilt device (1) according to any one of the preceding claims, further characterised in that the part (9) of each block unit (7) engageable by part (5) of an adjacent drawer (3) comprises a rotatably mounted roller (19) to ensure smooth movement of the block units (7) when engaged by part (5) of the drawer (3). A combined locking and anti-tilt device (1) according to claim 5, further characterised in that pairs of adjacent block units (7) include rollers (19) arranged in adjacent pairs such that opening of a drawer (3) causes part (5) to engage each roller (19) in the pair mounted upon the adjacent block units to cause smooth movement of the block unit (7) closest to the first end towards the first end and restrict movement of the other block unit in the pair. A combined locking and anti-tilt device (1) according to claim 6, further characterised in that each block unit (51) has two rollers (53,55) mounted upon it, the rollers (53,55) being mounted at opposite edges of the block unit (51). A combined locking and anti-tilt device (1) according to claim 4 and any one of claims 5 to 7, in which the plate (35) also includes elongate slots (43) through which rollers (19) pass, the length of the slots (43) being sufficient to allow sufficient relative movement between the locking plate (35) and the blocks (7). A cabinet including a combined locking and anti-tilt device (1) according to any one of the preceding claims. A cabinet according to claim 9, further characterised in that the part (5) of the drawer (3) which engages part (9) of an adjacent block unit (7) comprises an elongate side rail (5) including a tapered nose (17).

Inventors: LAW ANDREW JONATHAN, PARKER RAYMOND, LAW, ANDREW JONATHAN, PARKER, RAYMOND
Applicants: FLEXIFORM BUSINESS FURNITURE, FLEXIFORM BUSINESS FURNITURE LIMITED
Application year: 1995
Main classification: E05B65
IPC codes: E05B65