GB2398732A

GB2398732A - Powered opening and closing apparatus for drawers and doors

Info

Publication number: GB2398732A
Application number: GB0304296A
Authority: GB
Inventors: Jason Michael Chaplin
Original assignee: Individual
Current assignee: Individual
Priority date: 2003-02-26
Filing date: 2003-02-26
Publication date: 2004-09-01
Also published as: GB0304296D0

Abstract

An apparatus for opening and closing drawers 111 and cupboard doors mounted on runners 105 or hinges comprises a powered linear drive unit 10 mounted on the furniture housing and cooperating with a separate, disengageable driven member 40 mounted on the drawer or door. The drive unit preferably comprises a rotating threaded rod (11, Fig 1B) driving a profiled engagement block (50, Fig 1B) which translates along the unit and disengages the driven member at a predetermined load. Alternative and interchangeable driven members are disclosed, enabling the drive unit to be installed for use with both drawers and cupboard doors. The drive unit is preferably installed for opening a drawer in parallel with the drawer runner on a vertical side wall of the housing. Means are provided for disengaging the drive unit, enabling the drawer or door to be opened and closed manually. The apparatus may be installed in a medical or dental practice and operated by sanitisable switches flush mounted in a worktop.

Description

2398732 Powered opening and closing apparatus for furniture This invention

relates to powered devices for opening and closing items of furniture such as drawers and cupboard doors.

Items of furniture, which in this specification is taken to include movable elements such as drawers, cupboard doors and the like, whether in fixed or freestanding housings, are traditionally opened and closed manually by means of a handle to give access to the storage space within. However, this is sometimes difficult or undesirable. Some disabled persons for example may have difficulty in manipulating drawers, while those working in potentially contaminated environments may wish to minimise contact with handles in order to avoid the risk of cross contamination. Repetitive strain injury may result from repeated manual operation of heavy or awkwardly sited drawers. It may also be preferred to provide furniture with substantially flush, continuous outer surfaces, in order for example to avoid protruding handles which may catch on the user's clothing, or recessed handles which may act as reservoirs of contamination. In these and similar situations it is therefore desirable to employ powered means for opening and closing furniture such as drawers and the like.

Drawers are generally box shaped storage devices which are slidingly mounted in a furniture housing or carcass; each drawer is typically mounted at or adjacent its vertical sides on runners, which are sliding devices which support the weight of the drawer and its load whilst guiding the drawer as it slides in and out of the furniture housing. Generally the drawer is fitted snugly into the housing so as to minimise wasted storage volume, the sides of the drawer being just sufficiently spaced apart from the vertical sides of the housing to provide clearance for the runners. Often a number of drawers are supported one above another in a single housing by spaced-apart parallel runners attached to the vertical sides of the housing.

Drawers and cupboard doors are found in freestanding cabinets, fitted into fixed carcasses beneath worksurfaces, in specialist dental and hospital furniture, in vehicles and in numerous other situations, and in this specification the term "housing" is accordingly to be construed as including any housing or carcass, fixed or freestanding, in or on which a movable element such as a drawer or cupboard door is mounted. Drawers and cupboard doors vary according to their application in size and configuration, although in some applications, such as kitchen cabinets, their dimensions have become relatively standardized.

Drawer runners are well known and of diverse design, and are selected according to the requirements of the installation. They typically comprise upper and lower elongate members, attached respectively to the drawer and to the carcass, retained together by sliding bearing means enabling smooth reciprocal movement therebetween; additional elongate members may be interposed between the upper and lower members to extend their loadbearing capacity and range of travel. The bearing means may include wheels, ball bearings or the like. Often the lower member attached to the carcass includes a downwardly oriented section at its rearmost extremity; when the drawer is pushed into its closed position, the bearing means of the upper member attached to the drawer ride down this section, urging and retaining the drawer into the fully closed position.

Cupboard doors are similarly diverse in design and dimensions, and are typically hinged to the furniture housing at one edge. Cupboard doors may describe various complex motions as they open and close, depending on the geometry of the hinge mechanism employed, which is typically chosen to enable the door to fit snugly into its housing when closed whilst clearing the edges of the housing when it opens.

Various attempts have been made to provide powered devices for opening and closing items of furniture. US 3,028,209 to Hinkel discloses a motor mounted in a drawer and driving a pinion which protrudes through the side wall of the drawer and engages a rack fixed to the housing; similarly, US 2001/0013745 to Fulterer discloses a motor driven pinion mounted on the housing, cooperating with a rack mounted on a runner and controlled by light sensing means.

US 3,259,443 to Lavigne and Lorenzetti discloses a cabinet including drawer runners which incorporate motor driven threaded screws; each screw is rotated to displace the inner runner with respect to the outer. US 5, 080,451 to Brunnert similarly discloses a powered drawer runner which incorporates a linear motor for displacing the inner runner with respect to the outer. FR 2 476 193 to CRM discloses a motor driven belt mounted on an angled frame which is affixed to the housing beneath a drawer; the drawer is driven in and out by means of a bracket mounted on the upper surface of the belt.

All of the above apparatus require modification of the drawer or runner, or additional clearance between the drawer and its housing, in order to install the motor and drive mechanism, and the need therefore remains for a powered device which can readily be installed to open or close items of furniture of ordinary design without requiring special modification thereof. It is the aim of the present invention to fulfil this need.

According to a first aspect of the present invention there is provided an apparatus for opening and closing an item of furniture, the item of furniture including first and second surfaces mounted for relative displacement, one said surface comprising a movable element and the other said surface comprising a housing; the apparatus comprising powered reversible linear drive means adapted to be mounted on the first surface, control means for controlling the drive means, a driven member, first engagement means engaging the driven member with the drive means, and second engagement means engaging the driven member with the second surface, such that in use the driven member is driven by the drive means so as to effect relative displacement between the first and second surfaces; 1 characterized in that at least one of the said first and second engagement means includes disengagement means for disengaging the driven member respectively from the drive means or from the second surface.

According to a second aspect of the invention there is provided an apparatus for opening and closing an item of furniture, the item of furniture comprising a movable element and a housing, wherein the movable element comprises a; drawer, the drawer being slidably mounted on runners within the housing, the apparatus comprising powered elongate reversible linear drive means, control means for controlling the drive means, a driven member, first engagement means engaging the driven member with the drive means, and second engagement means engaging the driven member with the drawer, such that in use the driven member is driven by the drive means so as to open or close the drawer; characterized in that the drive means is adapted for mounting in parallel with a said runner on an inner vertical wall of the housing, and in that the driven member extends transversely to the length of the drive means from the drive means to the drawer.

According to a third aspect of the invention there is provided an apparatus for opening and closing an item of furniture, the item of furniture comprising a movable element and a housing, wherein the movable element comprises a cupboard door mounted on hinges on the housing; characterized in that the apparatus comprises powered reversible linear drive means, control means for controlling the drive means, a driven member, first engagement means engaging the driven member with the drive means, and second engagement means engaging I the driven member with the door, the driven member extending from the drive means to the door such that in use the driven member is driven by the drive means so as to open or close the door.

According to a fourth aspect of the invention there is provided an apparatus for I opening and closing an item of furniture, the item of furniture including first and t second surfaces mounted for relative displacement, one said surface comprising a s movable element and the other said surface comprising a housing; the apparatus comprising powered drive means adapted to be mounted on the first surface, control means for controlling the drive means, and a driven member engageable with the drive means and with the second surface, such that in use the driven member is driven by the drive means so as to effect relative displacement between the first and second surfaces; characterized in that the driven member is separable from the drive means.

It will be appreciated that the present apparatus can be installed in various types of furniture of generally standard design, without requiring special modification of cupboard doors, drawers or runners or enlargement of the furniture housing.

Further advantages and features of the invention will become apparent upon studying the following description wherein various illustrative embodiments of the invention are described by way of example and with reference to the accompanying drawings, in which: Fig. 1A is a side elevation (viewed in an installed position) of a first apparatus according to a first embodiment of the invention; Fig. 1 B shows the first apparatus with the cover removed; Figs. 2A, 2B and 2C are respectively side, plan and end views of the engagement block of the first apparatus; Fig. 3 is a side elevation of an interior wall of a housing containing two drawers, showing the first apparatus in an installed position; Figs. 4A and 4B show the first apparatus of Fig. 3 respectively before and after operation of the deactivation means; I 1 Fig. 5 is a plan view of a second apparatus according to a second embodiment of the invention, installed in a housing with a cupboard door near the closed position; Fig. 6 shows the second apparatus of Fig. 5 with the cupboard door in the open position; Fig. 7 shows the second apparatus of Fig. 5 after operation of the deactivation means; and l O Fig. 8 shows a side elevation of the driven member and second engagement means of the second apparatus.

Corresponding parts are referred to by the same reference numerals throughout.

Referring to Figs. 1A and 1B in a first preferred embodiment a first apparatus comprises powered elongate reversible linear drive means 10, which desirably comprise a rotatable threaded rod 11 driven by an electric motor 12 and fixedly mounted against longitudinal displacement in bearings 13 in an elongate body 20, which is conveniently moulded from aluminium or plastics material. Suitable gears (not shown) may be interposed between the motor and the rod. The body 20 is adapted for fixed mounting on a first furniture surface, preferably an interior surface of the furniture housing, by means of screw holes or the like (not shown), and has a cover 21 with a longitudinal slot 22. The body is conveniently divided into a motor compartment 23 and a compartment 24 for the threaded rod; the rod 24 may be greased, and the internal division of the body and the cover then assist in retaining the grease against spillage.

A thumbwheel 60 is mounted on the rod l I to be accessible through the cover 21, so as to form deactivation means as further described below.

Referring now to Figs. 1 and 2, a driven member 40 is engaged with the drive means 10 by first engagement means 50, comprising an engagement block 51 cooperating with a threaded block (not shown) together with the distal end 41 of the driven member 40, which in use engages a recess 52 in the engagement block.

The threaded block is threaded internally to cooperate with the rod 11, so that as the rod is rotated by the motor the threaded block translates axially along the rod.

The motor 12 is reversible so as to drive the first engagement means 50 in either direction along the longitudinal axis of the drive means, and is supplied with power via electrical wiring 30 and controlled by control means comprising user operable switch means (not shown), which will be described further below, and sensor switches 31, 32. Switch 32 is operated by a sensor pushbutton 33 which protrudes slightly through one end 25 of the body 20 to form position sensing means.

The engagement block 51 is retained slidingly in the slot 22 by a projecting rib 53 which fits into the slot; a horn 54 is formed on each end of the rib, and the horns embrace the threaded block (not shown) so that in use the engagement block 51 is driven longitudinally along the length of the drive means 10 as the rod l 1 rotates.

The engagement block 51 is conveniently moulded from plastics material, and may be retained by a clip or the like in the slot or to the threaded block; alternatively the engagement block and threaded block may be formed as a single unit, and the slot 22 widened to accommodate it; alternatively the distal end 41 of the driven member may be formed to project inwardly through the slot 22 and engage the single unit on the inside of the cover. Equivalent configurations will easily be conceived by those skilled in the art.

The driven member 40 desirably comprises a resilient leaf, which may be formed from a substantially flat sheet of spring steel, and the distal end 41 is conveniently formed by rolling the edges of the leaf into a tubular shape, forming smooth l rounded sides 42 which cooperate with the recess 52 in the engagement block. i Desirably, the mid section 43 of the driven member is elongate and in use extends upwardly or downwardly away from the drive means 10 from the drive means to the driven movable furniture element in a direction transverse or normal to the length of the drive means, as further described below.

By forming the driven member as a resilient leaf and orienting the flat sides of the leaf as shown in parallel with the longitudinal axis of the drive means, the advantage is realised that the driven member is substantially stiff in the direction of motion of the movable furniture element, and hence able to transmit substantial motive force from the drive means, whilst remaining flexible in a direction normal to its direction of motion. It will also be noted that the engagement of the distal end 41 of the driven member with the recess 52 of the engagement block creates a slidable, adjustable connection between the driven member and the drive means, such that the distal end 41 of the driven member may move up and down in the recess transversely to the direction of motion of the driven furniture element. This i adjustable connection together with the resilience of the driven member enables the driven member to absorb irregularities and inconsistencies in the motion and position of the movable furniture element with respect to the housing, and assists I in easy installation of the apparatus in a variety of different furniture types and configurations.

The opposite end 44 of the driven member is provided with second engagement means 45 which in use engage the driven member with a second furniture surface, which preferably comprises the movable or driven furniture element; conveniently the second engagement means comprise screw holes 46. This enables the driven ' member to be easily and quickly attached to the driven furniture element by i means of two screws or the like, whilst the slidable and adjustable connection of the first engagement means allows for a substantial margin of error in the positioning of the screws. Alternative arrangements of the second engagement means will readily be conceived.

It will be appreciated that the provision of a driven member which is separable from the drive means and releasably or adjustably engaged therewith greatly assists in the installation of the apparatus in a variety of different furniture configurations, by allowing for a degree of error or variation in the location of the drive means on the housing and the driven member on the movable furniture element, whilst still enabling perfect closure of the movable furniture element into its fully closed position. The provision of a sensor switch 32 on the body 20 where it is abutted in the closed position by the movable element further enhances the flexibility and ease of installation of the apparatus, as will be further described below.

The recess 52 in the engagement block 51 cooperates with the distal end 41 of the driven member 40 to form disengagement means 50 integral with the first engagement means, whereby the driven member may readily be disengaged from and reengaged with the drive means 10. This allows the apparatus to be quickly and easily installed in conventional furniture of various types, since the driven member may be conveniently separated from the drive means for attachment to the movable furniture element and the drive means separately attached to the furniture housing. By forming the driven member 40 as a separate member disengageable from the drive means, the advantage is also realised that variations in the design and configuration of different furniture housings - for example, the distance of the drawers from the sides of the housing - may be accommodated by the disengageable connection between the driven member and the drive means.

The disengagement means 50 include angled inner surfaces 52' in the recess 52 and adjacent outwardly angled surfaces 55 on the engagement block 51. These angled surfaces form disengagement surfaces which are arranged to urge the distal end 41 of the driven member out of engagement with the drive means 10 when a predetermined load is exerted on the engagement means. The engagement block 51 also includes angled reengagement surfaces 56 which form reengagement means for urging the distal end 41 of the driven member back into engagement with the recess 52 as further described below.

Referring to Figs. 3 and 4A, the first apparatus may be installed on an interior vertical wall 101 of a furniture housing 100. The housing contains drawers 110, 111 which are mounted one above the other on sliding runners 105, one of which can be seen in the drawing; for clarity the drawers are shown in cross section. The drawers and runners are of conventional design, so that the side wall 112 of each drawer is spaced apart from the interior wall 101 of the housing by little more than the width of the runner 105. Each drawer has a front panel 113 which is arranged to abut the front edge 102 of the housing when the drawer is fully closed ( 1 10), the front panels then forming together a substantially flush, continuous surface.

1 5 In the housing shown, the drawer runners 1 05 are located near the top edges 115 of the side walls 112 of the drawer; however, in other housings they may be located at the bottom edges 1 16 of drawer side walls, or anywhere in between, or even beneath the drawer, and in practice their precise location will vary from one furniture housing to another. Similarly, although the drawers in the furniture illustrated are shown as having front panels 114 which extend above the upper edges 1 15 of the drawer sides, other drawers may commonly be encountered which have front panels which extend little higher than the drawer side walls 112.

Many common drawer runners are separable to allow removal and replacement of the drawer from and into the housing without removal of the runner elements from the drawer or the housing. By providing disengagement means which allow the disengagement of the driven member from the drive means, it will be appreciated that the apparatus may therefore be particularly easily and quickly installed in drawers and housings of various common designs without modification of the drawer, runners or housing, by removing the drawer from the housing and installing the driven member and the drive means separately before 1 replacing the drawer in the housing and engaging the driven member with the drive means.

In an alternative embodiment, the second engagement means may include disengagement means such as, for example, a block similar to the engagement block S l, which is screwed to the drawer and engages or disengages the driven member; the driven member may then remain in engagement with the drive means. The block of the second engagement means may then be attached to the drawer before the drawer is replaced in the housing and the driven member engaged with the block.

The body 20 of the apparatus is preferably mounted, for example by means of screws, in parallel with the runner 105 on the interior vertical wall 101 of the housing so that the front end 25 of the body is adjacent the front edge 102 of the housing. The pushbutton 33 protrudes slightly beyond the housing, where the inner face 114 of the drawer front panel 113 abuts it when the drawer 111 is moved towards the fully closed position, as shown in Fig. 4A. The switch 32 is arranged to stop the motor 12 when the pushbutton 33 is depressed by the closing drawer.

Since it is relatively easy for the person installing the body 20 in the housing to ensure that the front end 25 of the body is accurately aligned with the front edge 102 of the housing during installation, and since it is the abutment of the front panel 113 of the drawer with the front edge 102 of the housing which determines that the drawer has reached its fully closed position, the arrangement of the sensor pushbutton 33 at the front end of the body 20 makes it easy for the installer to ensure that in operation the drawer reaches its perfectly closed position. All that is necessary is to align the front edge 25 of the body with the front edge 102 of the housing. Adjustment means such as a screw may be incorporated into the pushbutton 33 or switch 32 to enable fine adjustment after installation of the drive 1 1 means 10 in the housing. The sensor and switch 32, 33 may alternatively be substituted by a contactless proximity sensing device or the like.

The driven member 40 is conveniently attached by means of screws locating in the screw holes 46 to the vertical surface of one side wall 112 of the drawer. For clarity the driven member is shown attached to the interior face of the side wall 112, but in practice it may be attached to the exterior face so that it lies between the side wall 112 of the drawer and the interior wall 101 of the housing. Thus to install the apparatus in furniture where the runner 105 is located towards the bottom edge 116 of the drawer, the driven member may be attached for example to the outer surface of the drawer side wall at the bottom near the runner, and the drive means 10 mounted on the interior wall lot of the housing where it lies between the upper part of the drawer side wall and the housing.

Of course, it will be appreciated that the driven member and the drive means might be installed on an edge rather than a flat side of the furniture, or on a horizontal surface or in any other convenient position, and in this specification the term "surface" is accordingly to be construed as including any part of the furniture to which the apparatus may conveniently be attached.

In many housings containing several drawers mounted one above the other, with front panels of roughly the same height as the drawer side walls, there will often be no convenient horizontal surface on which the drive means may be mounted, and there may be little vertical separation between the side walls of adjacent drawers. In such installations the drive means is installed on the vertical side wall of the housing, and it is particularly advantageous for the drive means to be capable of installation in the limited clearance between the drawer side wall and the housing.

In order to facilitate location of the drive means 10 between the drawer side wall and the housing, the body 20 and drive means l O are preferably arranged as 1 1 shown with a low, flat profile, so that the body extends outwardly from the interior surface 101 of the housing by no more than the width (which is to say, the transverse dimension when viewed in plan) of the runners 105. Since drawer runners are typically of the order of 20mm to 35mm in width, the width (which is to say, the transverse dimension when viewed in plan in the installed position on a vertical surface) of the drive means 10 and body 20 is therefore desirably less than 35mm, preferably less than 25mm and most preferably less than 20mm. It is found that these dimensions may achieved in practice by using a low profile electric motor and a threaded rod as described above. Those skilled in the art will understand however that other drive means such as a linear motor, pneumatic actuator or the like might alternatively be used, together with suitable control means.

In the installed position the drive means 10 extends horizontally as shown in parallel with the drawer runners 105 and substantially towards the back of the housing 100. The driven member 40 extends transversely to the direction of motion between the drawer and the drive means, so that as the drawer slides in and out of the housing the distal end 41 of the driven member 40 translates along the longitudinal axis of the drive means.

By arranging the drive means to be mounted on the inner vertical wall 101 of the housing in parallel with the existing drawer runner, for example between the side of the drawer and the side wall of the housing, and arranging the driven member to extend transversely from the drive means to the drawer so as to transmit the drive to the drawer, it is thus seen that the apparatus may easily and quickly be installed to automate a drawer 111 of conventional design, mounted on conventional runners in a standard housing, without requiring modification of the drawer or the housing, replacement of the runners or removal of the runners from the housing. The provision of a separable driven member makes it easier still to instal the apparatus.

A dummy body 20 may be provided for installation on the opposite side of the housing from the active body 20 so as to provide a symmetrical appearance to the user.

The driven member 40 is preferably resiliently biased into engagement with the recess 52 in the engagement block 51, for example by shaping the leaf so that it is angled outwardly away from the engagement means 45. The sliding, adjustable connection between the distal end 41 of the driven member and the engagement block 51 thus allows the driven member to compensate for inaccuracies and variations in the construction or alignment of the drawer, runners or housing, as well as allowing for considerable variation in the exact location of the driven member on the drawer. The adjustable engagement of the distal end 41 of the driven member in the recess 52 also allows the driven member to absorb the slight downward motion of the rear end 117 of the drawer in the closed position when the bearings of the drawer runner 105 ride down the slight downward ramp which is often formed at the rear end of the runner as described above.

Variations in the distance between the drawer sides and the housing in different furniture configurations are similarly accommodated by the resilience of the driven member and the adjustable connection between the driven member and the drive means, further assisting the installation of the apparatus in items of furniture of varying designs. The elongate shape of the driven member combined with its generally downward, transverse orientation from the drive means to the drawer further enhances the flexibility of installation of the apparatus by allowing the driven member to adopt a variable angle to the vertical to compensate for differences in the furniture configuration. The flat side of the leaf 40 facing the housing may be forced by its resilient bias into a slightly convex shape when in the installed position, so that the distal end 41 lies against the engagement block 51 in a substantially vertical orientation.

It will readily be appreciated that instead of extending downwardly from the drive means to the drawer, the driven member may alternatively extend generally upwardly from the drive means to the drawer, the drive means then being mounted for example below the drawer runner. Alternatively, thedriven member may extend substantially horizontally from the drive means to the drawer. The driven member may also take alternative forms to that illustrated; for example it may be formed as a rigid rod, a bracket, a rubber link, a sprung stud or the like engaging the drive means or the drawer, and may be resiliently biased for example by means of a coil spring. Similarly, whilst the driven member is preferably resiliently biased, it may alternatively be formed without resilient biasing means. The disengagement means may for example include a resilient clip or the like which engages a rigid driven member. Alternative constructions will readily be conceived by those skilled in the art.

The motor 12 is advantageously arranged at the rear end 26 of the body, which may extend towards the rear of the housing beyond the rear end 1 17 of the drawer. In an alternative configuration the motor may be arranged at the side of the rod and connected to it by means of gears or the like; the slot may then extend to the rear end of the body so that the driven member may traverse the full length of the body. The driven member is preferably attached close to the rear end 1 17 of the drawer so that the engagement means 50 lies close to the rear end 26 of the body 20 when the drawer is fully closed; this maximises the distance of travel of the engagement means and enables the drawer to open as fully as possible. However, it will be noted that by mounting the driven member further from the rear end 1 17 of the drawer it is possible to use the same length drive means to operate a longer drawer in a deeper housing, the drawer then opening slightly less fully before the engagement means reaches the limit of its travel near the front end of the drive means. Thus drawers of varying depths may be automated by installing drive means which are manufactured according to the invention in only one or a few selected lengths.

The apparatus is conveniently controlled by the user by means of a user operable switch, such as a conventional switch, a proximity switch, a light sensor, a security switch using a key or card reader or the like, or any other type of switch, which is arranged to start and/or stop the motor 12. The switch may also be arranged to selectively determine the direction of rotation of the motor and hence the direction of movement of the drive means and the drawer; alternatively or additionally, sensor switches 31, 32 may be arranged to determine the direction of rotation of the motor by means of an electronic or manual toggle switch, changeover contacts or the like, as will be readily understood by those skilled in the art. The switch is arranged in a convenient location and connected to the drive means via wiring 30, which cooperates with the sensor switches 31, 32 and supplies current to the motor from a convenient supply.

In use, the driven member remains in engagement with the engagement block 51 so that when the motor 12 is operated the engagement block 51 translates axially along the rod 11 and drives the driven member 40 longitudinally along the body 20, opening or closing the drawer. When the engagement block reaches the front end of the slot 22, the threaded block contacts the sensor switch 32 which stops the motor with the drawer in the open position. In order to close the drawer, the user operates the switch to rotate the motor in the opposite direction, and the engagement block is driven back along the length of the drive means 10 until the inner face 114 of the front panel of the drawer contacts the sensor button 33, stopping the motor with the drawer in the fully closed position.

Those skilled in the art will appreciate that timing means or the like may readily be incorporated into the control means so that various operational characteristics may be imparted to the apparatus; for example, the drawer may close automatically after a certain period, or remain closed for a certain period before reopening, and so forth. Sensors may also be provided for sensing pressure against the drawer so as to initiate or interrupt the closing or opening operations. Other refinements of the control system will readily be conceived.

In environments such as dental, medical and veterinary practices, laboratories and food processing areas, as well as in domestic kitchens and the like, it is desirable that the risk of cross contamination from frequently touched surfaces such as handles, switches and the like should be reduced as far as possible. Many drawer or cupboard housings in such environments are provided with a washable worktop or the like, and in a particularly preferred embodiment the user operable switch is formed as a washable switch, such as a membrane type switch, which is flush mounted in the washable surface of the worktop. This ensures that when the worktop is wiped down, as will occur regularly in the course of basic good hygiene practice, the switch is also sanitised, reducing the risk of cross infection.

The drawers or cupboards as further described below may thus be opened and closed as required and without special precautionary procedures, but with greatly reduced risk of cross contamination, for example in order to access equipment stored therein during medical or dental procedures.

In these and other environments there may also be a risk of casual theft of drugs, instruments or the like which are stored in drawers and cupboards. The apparatus according to the invention enjoys the further advantage that the drawer and cupboard fronts of an otherwise standard installation may be selected so as to present a smooth, flush and continuous surface, making it difficult for the casual opportunist to gain access without using the switch. The switch may then be protected by a key or the like, or located in a protected place, so that a useful additional level of security is achieved.

It is envisaged that a panel of switches may thus be mounted together in a worktop or another external surface, each switch controlling an individual apparatus for opening and closing an individual drawer or cupboard door as further described below. Operation of all of the switches may then be enabled or disabled by means of a central key switch or the like.

The disengagement means 50 are preferably formed as safety means which disengage the driven member 40 automatically at a predetermined load. This i ensures that in the event of a person or object becoming trapped between the closing drawer 111 and the housing, or obstructing the opening drawer, the drawer is disengaged from the drive means 10 so as to avoid damage or injury.

This is conveniently achieved by means of the angled disengagement surfaces 52', S 55, which urge the rounded sides 42 of the distal end 41 of the driven member out of engagement with the engagement block 51 at a load which is predetermined inter alla by the depth of the recess 52, the angle of the ramped disengagement surfaces, the smoothness, lubricity and other material characteristics of the recess 52 and the sides 42 of the driven member, and the resilient loading of the driven member 40 against the engagement block 51. Thus when the moving drawer is obstructed, the moving engagement block 51 forces the distal end 41 of the driven member 40 up the angled disengagement surfaces and away from the block 51, so that the engagement block 51 continues to move along the drive means 10 but the drawer 111 is disengaged.

The safety disengagement means described benefit in that disengagement is reliably achieved in the event of an obstruction. Alternatively or in addition however, the power of the motor 12 may be limited, or a sensor or the like may be arranged to sense the obstruction, for example by sensing the current drawn by the motor, and stop the motor. Equivalent arrangements will be readily apparent to those skilled in the art.

Desirably, the disengagement block 51 is also provided as described above with angled reengagement surfaces 56 which are arranged to urge the distal end 41 of the driven member back into engagement with the recess 52. This enables the user to reengage the driven member with the drive means, for example following disengagement or during installation, merely by grasping the drawer 111 and firmly moving it towards the closed or open position so that the distal end 41 of the driven member rides up the ramped surfaces 56 and resiles into the recess 52.

The drawer may also be disengaged by the user by following the reverse procedure so as to push or pull the drawer against the drive means with a force greater than the predetermined load. This is particularly useful for example in the event of a power failure or malfunction, enabling the user to open or close the drawer manually.

Where the drawer front 113 is arranged as described above to form a flush or continuous surface, the user may be provided with a tool which slips into the narrow gap around the drawer front so as to hook around the front panel 1 13, enabling the user to pull the drawer open against the predetermined load of the engagement means. Thus the drawer may be opened manually in an emergency whilst still providing an effective barrier to the casual thief. Alternatively a handle or the like may be provided on the front of the 1 0 drawer.

The apparatus is preferably adapted to allow the drawer to be opened and closed manually after disengagement of the driven member; thus after disengagement from the engagement block 51, the driven member may slide freely along the cover 21 of the 1 S drive means as the drawer 1 1 1 is opened and closed by the user. This ensures that the drawer remains fully usable in the event of a failure.

Referring to Figs. 4A and 4B, the thumbwheel 60 is mounted on the threaded rod 11 so that the user can push it in the direction of the arrow 61 to rotate the rod manually, moving the engagement means SO into the disengaged position shown in Fig. 4B, where the engagement block 51 lies at the extreme rear end of the slot 22 beyond the rearmost position of the driven member 40 when the drawer is fully closed. Alternatively of course the engagement block 51 might be moved to the extreme forward end of the slot 22 so that it remains out of engagement with the driven member. Of course, the thumbwheel might alternatively be arranged between the motor and the gears, particularly where the gear train has a relatively high ratio; it will be understood also that the pitch of the thread on the rod may vary from that shown in the drawings, which is purely illustrative.

The thumbwheel 60 thus forms manual deactivation means whereby the user may move the engagement means into a disengaged position where the driven member remains disengaged from the drive means and the drawer 111 may be opened and closed manually. By rotating the thumbwheel in the opposite direction, the user may return the engagement means 50 to the engaged position shown in Fig. 4A, where the driven member 40 may be reengaged in the recess 52 by manually pushing the drawer against the predetermined load of the engagement means so as to force the driven member 40 back into place. The apparatus may then resume its normal function.

Automatic deactivation means might alternatively or additionally be provided, comprising for example a manually selectable sensor switch which stops the movement of the motor only when the engagement means 50 has reached the extreme rearmost disengaged position, thereby automatically disengaging the driven member by the continued motion of the drive means when the front panel 1 13 of the drawer abuts the housing in the closed position.

Referring now to Fig. 5, in a second embodiment of the invention a second apparatus is shown installed on an interior vertical side wall 201 of a cupboard housing 200 to open and close a vertically mounted cupboard door 210. The cupboard door 210 is mounted on hinges, which for clarity are not shown, on the housing 200.

The apparatus comprises powered reversible linear drive means 10 and first engagement means, comprising an engagement block 51 for engaging a driven member, which desirably are identical to those described above with reference to the first embodiment. Control means identical to those of the first embodiment are similarly provided, including a sensor button 33 as described above. It will be understood that this enables a standard drive unit 10 to be installed either in a drawer housing or in a cupboard housing so as to open and close either a drawer or a cupboard door, resulting in savings in manufacturing, stockholding and maintenance costs and convenience for the installer.

The drive means 10 functions as described above, and is installed in the housing with the front end 25 of the body aligned with the front edge 202 of the housing as described above, so that the sensor button 33 abuts the inner face 214 of the cupboard door 210 in the closed position.

In contrast to the driven member of the first apparatus, a different driven member 70 is provided which extends from the drive means 10 to the cupboard door 210.

The driven member 70 preferably comprises a cranked arm, which is to say an arm with at least two sections 71, 72 arranged at an angle to each other. A pin 73 or the like is provided on one end of the driven member and engages with the recess 52 as described above in the engagement block 51 to form first engagement to means 50, which engage the driven member with the drive means as described above with reference to the first apparatus. It will be noted that in this embodiment the driven member 70 does not move laterally with respect to the engagement block 51, but the pin 73 is free to pivot in the recess 52.

The driven member 70 engages the door 210 by second engagement means 80, comprising a bracket 81 which is conveniently screwed to the door 210 and is articulated to the arm 70 by means of a pivot 82, which is arranged substantially parallel with the axes of the door hinges (not shown).

Referring to Fig. 8, the arm 70 is conveniently formed from two flat struts 74, 75, and is resiliently biased into engagement with the engagement block 51 by means of a spring 76 which is conveniently arranged between the bracket 81 and the arm 70; equivalent constructions will easily be conceived.

Referring to Figs. 5 and 6, in operation the first engagement means 50 is driven by the drive means l O along the length of the body 20 as already described, urging the arm 70 to rotate about the pivot 82 as it opens and closes the door. In the open position, shown in Fig. 6, the cranked shape of the arm 70 enables it to clear the front edge 202 of the housing and the front end 25 of the drive means. The clearance between the arm and the housing and the freedom of movement of the arm about the pivot 82 and the pin 73 engaged in the recess 52 enables the arm 70 to accommodate the different geometries of motion which various designs of hinge may commonly impart to the cupboard door 210.

It is to be understood that the engagement, disengagement, reengagement and deactivation means and other features described above with reference to the first embodiment are enjoyed mutatis mutandis by the apparatus of the second embodiment.

Referring to Fig. 7, the driven member 70 is thus shown in the disengaged position following deactivation by the user by means of the thumbwheel 60; the arm 70 is thus free to slide along the body 20 of the drive means, enabling the user to open and close the cupboard door freely. By rotating the thumbwheel in the opposite direction the engagement block 51 is advanced towards the front end 25 of the body so that the arm can be reengaged by pushing the cupboard door inwards against the predetermined load of the first engagement means 50.

By providing two interchangeable driven members 40 and 70 as described above, each being separable from the drive unit and each cooperating with the engagement block 51 so as to be separately and alternatively engageable with the drive means, the invention thus provides an apparatus comprising a drive means and a driven member as two separable elements which may be installed in a furniture housing to operate either a drawer or a cupboard door, the correct driven member being selected according to the installation and simply engaged with the drive means once the two elements have been installed. The apparatus may thus easily and simply be installed in a wide variety of commonly available furniture housings without modification of the housing or of the movable element.

In summary, an apparatus for opening and closing drawers and cupboard doors mounted on runners or hinges comprises a powered linear drive unit mounted on the furniture housing and cooperating with a separate, disengageable driven member mounted on the drawer or door. The drive unit preferably comprises a 1 rotating threaded rod driving a profiled engagement block which translates along the unit and disengages the driven member at a predetermined load. Alternative and interchangeable driven members are disclosed, enabling the drive unit to be installed for use with both drawers and cupboard doors. The drive unit is preferably installed for opening a drawer in parallel with the drawer runner on a vertical side wall of the housing. Means are provided for disengaging the drive unit, enabling the drawer or door to be opened and closed manually. The apparatus may be installed in a medical or dental practice and operated by sanitisable switches flush mounted in a worktop.

In the embodiments illustrated, the drive means is mounted on the housing and the driven member is engaged with the drawer or door; alternatively however the drive means may be mounted on the movable furniture element and the driven member engaged with the housing. In this less preferred configuration it is necessary to provide power to the drive means as it moves together with the drawer or door, for example via flexible wiring, which requirement is avoided by mounting the drive means in the preferred configuration on the housing and the driven member on the movable element.

Similarly, in the apparatus shown the first engagement means includes disengagement means for disengaging the driven member from the drive means.

Alternatively or additionally however, the second engagement means may include disengagement means, which may be formed and function similarly to the disengagement means shown, for disengaging the driven member from the drawer or door, or where the drive means is mounted on the drawer or door, for disengaging the driven member from the housing. For example, the second engagement means might include a block having a front face shaped similarly to that of the engagement block 51, but with a flat rear face which is screwed to the drawer or cupboard door or to the housing. The front face of the block then engages the driven member so as to form disengagement means.

Alternatively, in embodiments of the invention the disengagement means may be omitted and the drive means and driven member installed together on the side wall of the housing as described above. In this case particularly the drive means preferably includes means for limiting the force applied to the movable furniture element, such as a motor of limited power or a sensor.

Alternative drive means, such as linear motors, pneumatic actuators and the like, and other variations of the invention will readily be conceived by those skilled in the art, and the present invention is accordingly not limited to the embodiments described, but rather is intended to embrace all such variations and equivalents within the scope of the appended claims. 1 1

Claims

1. An apparatus for opening and closing an item of furniture, the item of furniture including first and second surfaces mounted for relative displacement, one said surface comprising a movable element and the other said surface comprising a housing; the apparatus comprising powered reversible linear drive means adapted to be mounted on the first surface, control means for controlling the drive means, a driven member, first engagement means engaging the driven member with the drive means, and second engagement means engaging the driven member with the second surface, such that in use the driven member is driven by the drive means so as to effect relative displacement between the first and second surfaces; characterised in that at least one of the said first and second engagement means includes disengagement means for disengaging the driven member respectively from the drive means or from the second surface.

2. An apparatus for opening and closing an item of furniture, the item of furniture comprising a movable element and a housing, wherein the movable element comprises a drawer, the drawer being slidably mounted on runners within the housing; the apparatus comprising powered elongate reversible linear drive means, control means for controlling the drive means, a driven member, first engagement means engaging the driven member with the drive means, and second engagement means engaging the driven member with the drawer, such that in use the driven member is driven by the drive means so as to open or close the drawer; 1 1 characterized in that the drive means is adapted for mounting in parallel with a said runner on an inner vertical wall of the housing, and in that the driven member extends transversely to the length of the drive means from the drive means to the drawer. s

3. An apparatus for opening and closing an item of furniture, the item of furniture comprising a movable element and a housing, wherein the movable element comprises a cupboard door mounted on hinges on the housing; characterized in that the apparatus comprises powered reversible linear drive means, control means for controlling the drive means, a driven member, first engagement means engaging the driven member with the drive means, and second engagement means engaging the driven member with the door, the driven member extending from the drive means to the door such that in use the driven member is driven by the drive means so as to open or close the door.

4. An apparatus according to claim 2 or claim 3, characterized in that at least one of the said first and second engagement means includes disengagement means for disengaging the driven member.

5. An apparatus according to claim 1 or claim 4, characterized in that the driven member is resiliently biased into engagement with the said at least one engagement means.

6. An apparatus according to any of claims I, 4 or 5, characterized in that the apparatus is adapted to allow the item of furniture to be opened and closed manually after disengagement of the driven member. 1 1

7. An apparatus according to claim 6, characterised in that the drive means includes deactivation means operable by a user for moving the said at least one engagement means into a disengaged position, wherein the driven member remains disengaged and the item of furniture may be opened and closed manually; and in that the deactivation means is further operable by the user to return the engagement means to an engaged position wherein the driven member may be reengaged.

8. An apparatus according to any of claims 1, 4, 5, 6 or 7, characterised in that the disengagement means disengage the driven member at a predetermined load.

9. An apparatus according to claim 8, characterised in that the disengagement means include at least one angled disengagement surface, and the disengagement surface urges the driven member out of engagement at the predetermined load.

10. An apparatus according to any of claims 1, 4, 5, 6, 7, 8 or 9, characterised in that reengagement means are provided whereby following disengagement, the driven member may be reengaged by a user by manually moving the item of furniture towards the open or closed position.

11. An apparatus according to claim 10, characterised in that the reengagement means includes at least one angled reengagement surface, and the reengagement surface urges the driven member into engagement when the item of furniture is manually moved towards the opened or closed position.

12. An apparatus according to claim 1 or claim 2, characterised in that the driven member comprises a resilient leaf.

13. An apparatus according to claim I or claim 3, characterised in that the driven member comprises a cranked arm and the engagement means include at least one pivot.

14. An apparatus according to any preceding claim, characterised in that the drive means includes an elongate body with a first end, and the control means includes sensing means for sensing the position of the movable element, wherein the sensing means is arranged on the first end of the body and the body is mounted on an inner surface of the housing such that the first end is adjacent a front edge of the housing, such that the movable element abuts the sensing means in the closed position so as to interrupt the closing action of the drive means.

15. An apparatus according to any preceding claim, characterized in that the drive means includes a rotatable threaded rod and the first engagement means includes a block cooperating with the rod and mounted for axial translation therealong, such that in use the rod is rotated to drive the block along the rod.

16. An apparatus according to any preceding claim, wherein the housing includes a washable exterior surface, characterized in that the control means includes washable switch means operable I by a user and flush mounted in the washable exterior surface.

17. An apparatus for opening and closing an item of furniture, the item of furniture including first and second surfaces mounted for relative displacement, one said surface comprising a movable element and the other said surface comprising a housing; the apparatus comprising powered drive means adapted to be mounted on the first surface, control means for controlling the drive means, and a driven member engageable with the drive means and with the second surface, such that in use the driven member is driven by the drive means so as to effect relative displacement between the first and second surfaces; characterised in that the driven member is separable from the drive means.

18. An apparatus according to claim 1 or claim 17, characterized in that at least two interchangeable driven members are provided, and each said interchangeable driven member is separately and alternatively engageable with the drive means such that the drive means may be installed with a first said interchangeable driven member wherein the movable element comprises a drawer, and may alternatively be installed with a second said interchangeable driven member wherein the movable element comprises a cupboard door.

19. An apparatus substantially as described herein with reference to the

IS accompanying description and drawings.