WO2018037222A1

WO2018037222A1 - Knife sterilisation

Info

Publication number: WO2018037222A1
Application number: PCT/GB2017/052475
Authority: WO
Inventors: Paul Anderson
Original assignee: Paul Anderson
Priority date: 2016-08-23
Filing date: 2017-08-22
Publication date: 2018-03-01
Also published as: GB201902138D0; GB201614385D0; GB2567389B; GB2567389A

Abstract

An ultra-violet (uv) knife sterilising system (1 ) comprises a knife sterilising cabinet (100) for sterilising hand knives (2, 3). The cabinet comprises a housing (10), a cavity (12) within the housing and at least one uv light source (16) that is configured to illuminate the cavity with uv light (17) for sterilisation of a knife within the cavity. The knives (2,3) to be sterilised will normally have a handle (22), a blade (23) and a shoulder (27) between the handle and the blade. The housing has a pair of apertures (4,5) each affording passage (20) for a corresponding knife inserted blade-first into the cavity. The cabinet has at least one pair of blade guides (4, 5, 26, 28) within the housing that are configured to engage with a knife to guide movement of the blade during insertion and removal of the knife. Within the cavity is at least one pair of carriages (34, 34') moveable along opposite first and second directions (36,36') relatively away from and towards a corresponding aperture. Each carriage carries an abutment (38) for making abutting contact with the corresponding knife shoulder during the guided movement of the blade. The pair of carriages are interlinked (40) whereby, in use, movement of a first carriage (34) in the first direction (36) caused by the abutting contact during insertion of a first one (2) of the knives through a first aperture (4) causes movement of a second carriage (34') in the second direction (36'), such that a second one (3) of the knives previously inserted into a second aperture (5) is moved outwards from the second aperture to assist removal of the second knife from the second aperture.

Description

Knife Sterilisation

BACKGROUND a. Field of the Invention

The invention relates to a knife sterilising cabinet for ultra-violet (uv) sterilisation of knives, for example hand knives used by workers in the catering or food preparation industries. b. Related Art

In the field of food processing, particularly the processing of meat products, it is necessary to sterilise the cutting blades of hand knives used by workers to cut or slice vegetables and other food products, and particularly meat. One common way is to use a hot water sterilising bath into which the knives are inserted. The water needs to be at no less than about 82 °C.

Such thermal sterilisers are very inefficient in terms of energy usage. Not only is heat lost radiantly, but usually the hot water container will have an overflow, so that the water does not get too dirty, and needs to be kept topped up. In the UK, the energy costs of a hot water knife sterilising station on a food production line may be around £1600 per year. A further problem arises in that the knife handles may get too hot to touch, which may be a safety hazard. To keep the handles cool, these are not typically immersed in hot water, but then the handles will not be sterilised at all. This is a particular problem with the part of the handle closest to the blade, which is more likely to become contaminated as a result.

It is an object of the present invention to provide a more convenient way of sterilising knives. SUMMARY OF THE INVENTION

According to a first aspect of the invention, there is provided a knife sterilising cabinet for sterilising knives, said knives each having a handle, a blade and a shoulder between the handle and the blade, said cabinet comprising:

a housing;

a cavity within the housing;

at least one ultra-violet (uv) light source, said light source being configured to illuminate the cavity with uv light for sterilisation of at least a part of a knife within the cavity;

at least one pair of apertures in the housing, the or each pair consisting of a first aperture and a second aperture, and each aperture affording passage for a corresponding knife inserted blade-first through said aperture into the cavity to be sterilised by said uv light and then removed blade-last out from said aperture;

- for the, or each pair of apertures, a pair of blade guides within the housing, said pair of blade guides consisting of a first blade guide being associated with the first aperture and a second blade guide being associated with the second aperture, and each blade guide being configured to engage with a knife to guide movement of said blade during said insertion and removal of said knife; and

- for the, or each pair of apertures a pair of carriages within the cavity, said pair of carriages consisting of a first carriage and a second carriage, and each carriage being moveable along opposite first and second directions relatively away from and towards a corresponding aperture and each carriage carrying an abutment for making abutting contact with a corresponding shoulder during said guided movement of said blade;

wherein for each pair of carriages said first and second carriages are interlinked whereby, in use, movement of the first carriage in the first direction caused by said abutting contact during insertion of a first one of said knives through the first aperture causes movement of the second carriage in the second direction, such that a second one of said knives previously inserted into the second aperture is moved outwards from the second aperture to assist removal of the second knife from the second aperture. According to a second aspect of the invention, there is provided a knife sterilising system, comprising a knife sterilising cabinet, the knife sterilising cabinet being according to the first aspect of the invention, and at least two knives including a first knife and a second knife, each knife having a handle, a blade and a shoulder between the handle and the blade, wherein said knives are each shaped to be received blade-first by said first and second apertures and to be engaged by said first and second blade guides to guide movement of said blades during said insertion and removal of said knives, whereby, in use, said blades when inserted into the cavity are sterilised by ultra-violet (uv) light within the cavity, and the blade handle of each one of said inserted knives is ejected from one of said first and second apertures upon subsequent insertion of another one of said knives into the other one of said first and second apertures.

Preferably, the length of each knife handle is such that the length of each knife handle is fully received within the aperture when the knife is inserted into the aperture.

Each blade guide may comprise a channel aligned with a corresponding one of the apertures. Each channel is then configured to engage with a handle of a corresponding knife to guide movement of the blade during the insertion and removal of the knife.

Each blade guide preferably comprises a slot carried by the carriage, each slot being configured to engage with a blade of a corresponding knife to guide movement of the blade during the insertion and removal of the knife.

Each blade guide may comprise a funnel carried by the carriage, each funnel having a mouth that faces towards a corresponding one of the apertures for receiving and guiding a tip of the blade into the slot.

Each abutment may be provided by an inner surface of the funnel.

In preferred embodiments of the invention, each abutment is provided by a surface that extends away from the slot which may, for example, be an inner surface of the funnel.

In some embodiments, each blade guide comprises first and second slots carried by the carriage, each slot being configured to engage with a blade of a corresponding knife to guide movement of said blade during said insertion and removal of said knife. The second slot may be spaced from the first slot along the first direction. With this arrangement, the first and second slots are aligned to keep the knife aligned with the insertion (first) direction as the knife is guided into the carriage. Each slot may be associated with a respective funnel carried by the carriage, each funnel having a mouth that faces towards a corresponding one of said apertures for receiving and guiding a tip of said blade into the corresponding slot. Each abutment may be provided by an inner surface of the funnel associated with the first slot.

Each carriage is preferably movable along a guide rail that extends between opposite surfaces within the housing, for example opposite surfaces provided by opposite walls of the housing. In some embodiments, a pair of parallel guide rails is provided for each carriage.

The guide rail may be any type of elongate guiding feature. In illustrated embodiments of the invention, the guide rails are guide rods.

In some embodiments of the invention, the pair of carriages is provided as part of a removable carriage module that is removeably affixed within the housing. The guide rails then may extend between end plates or end brackets of the module.

The carriage may comprise a sleeve that is slidably engaged with a corresponding guide rail. The sleeve and guide rail may both be cylindrical. The sleeve may include one or more bushings for engagement with the guide rail.

Each carriage may comprise an arm that extends between the corresponding guide rail and funnel. Each arm may extend substantially at right angles to the first and second directions.

The guide rails may be arranged with respect to the uv light such that the guide rails do not cast a shadow on the corresponding one of the blades when inserted.

Preferably, the first and second carriages of each pair of carriages are passively driven by the movement of each inserted knife.

For example, the first and second carriages of each pair of carriages may be interlinked by a passive mechanical linkage, rather than being actively driven by an active mechanical linkage, for example a linkage comprising electric motors operated under the control of control electronics.

In preferred embodiments of the invention, the mechanical linkage is passive, as opposed to being actively driven by an external power source, whereby movement of one carriage in the first direction caused by a worker inserting one knife drives the movement of the other carriage in the second direction out from the sterilising cavity. The mechanical linkage may comprise a flexible linkage between the carriages, such as a wire linkage. In preferred embodiments of the invention, the wire linkage comprises a first portion and a second portion, the first portion extending away from the first carriage substantially in the second direction and the second portion extending away from the second carriage substantially in the second direction. The first and second portions are then linked together by a third portion of the wire linkage, the third portion extending around a loop provided by a wire track between the first and second portions of the wire linkage.

The wire track may comprise a tubular guide for guiding movement of the wire.

Alternatively, or additionally, the wire track may comprise a roller guide for guiding movement of the wire. The wire track may guide the third portion around an arc of substantially 180°.

A flexible linkage comprising a chain, cord, or any other flexible elongate member may be provided instead of a wire linkage. The mechanical linkage may comprise one or more rigid levers in addition to or instead of flexible members.

The uv light source is preferably configured to project uv light in a projection direction towards the knife blades. The blade guides are advantageously configured to orient the blades substantially parallel with one another with one of the narrow edges of the blades, for example the cutting edge or the blade spine, facing towards the projection direction.

The cabinet preferably has reflective interior surfaces, whereby broad surfaces of the blades are illuminated substantially by uv light reflected from the surfaces and not directly from the projected uv light.

Preferably, the entire knife blade is received within the cavity for illumination with uv light when the knife has been inserted through an aperture and the respective carriage has been moved in the first direction. Thus no portion of the blade remains unsterilised after use. More preferably, at least a part of the knife handle is also received within the cavity for illumination with uv light when the knife has been inserted through an aperture and the respective carriage has been moved in the first direction.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be further described, by way of example only, and with reference to the accompanying drawings, in which:

Figure 1 is a perspective view from one side of a uv knife sterilising system according to a first preferred embodiment of invention, showing a knife sterilising cabinet having a sterilising cavity into which the blades of two knives have been inserted through a corresponding pair of apertures in one end wall of a first, main part of an external housing;

Figures 2 and 3 are views of the knife sterilising system of Figure 1 , showing a second part of the housing of Figure 1 when disconnected and separated from the main part of the housing;

Figure 4 is a view of the main part of the housing of the knife sterilising system of Figure 1 , one corner of which is drawn partially cut away to expose internal components of the cabinet including a pair of interlinked carriages that locate and support two knives that have been inserted blade first into a pair of apertures in an upper face of the cabinet;

Figure 5 is a view of the second part of the housing, which houses a uv light source including a pair of uv discharge lamps configured to project uv light into the sterilising cavity;

Figure 6 is a view of the second part of the housing, part of which is outlined in phantom to show the location of a power supply and ballast for driving the discharge lamps;

Figure 7 is a view of a main part of the housing in a second embodiment of invention, in which the uv sterilising cavity is configured to receive two carriage modules (one of which is illustrated), each carriage module having a pair of interlinked carriages;

Figure 8 is a view of the carriage module of Figure 7;

Figure 9 is a view of a removable top plate for the main housing of Figure 7, having two pairs of apertures for receiving up to four knives, one side of the top plate having a magnet the proximity of which is used by a corresponding magnetic sensor in the second housing portion to provide a safety cut-off to the power supply when the second part of the housing is disconnected from the main part of the housing; and

Figure 10 is a view of a carriage module of a third embodiment of the invention.

DETAILED DESCRIPTION

Figures 1 to 5 illustrate various views of a first embodiment of a uv knife sterilising system 1 , comprising a knife sterilising cabinet 100 and also a pair of knives 2, 3 shown inserted into a pair of corresponding apertures 4, 5 in a top face 6 of a main part 8 of a housing 10. Optionally, depending on the dimensions of the housing, there may be an additional one or more pairs of apertures. In Figure 1 , the location for one additional pair of apertures is shown in dashed outline 4', 5'. The subsequent illustrations omit these additional apertures, and corresponding internal components, particularly additional sets of a pair of interlinked carriages to be described below, only for the purpose of clarity in the drawings and conciseness in the description.

The main part 8 of the housing 10 has an interior which provides a sterilising cavity 12 and is removeably connected to a second part 14 of the housing which houses a uv light source 13 including a pair of uv discharge lamps 19 configured to project uv light into the sterilising cavity 12. In Figure 5, this uv light is indicated schematically by curved arrows 17. The lamps may be mercury vapour uv lamps. Although not illustrated, a wire screen protection and/or uv-transparent window may be provided to enclose and protect the lamps on the projection side of the second housing portion.

The tubes each consume around 15 W to 25 W of electrical power, provided by a power supply and ballast circuit 59, provided within the housing second portion. The tubes are between about 150 mm to 250 mm long and provide an output of 1600 μνν/cm² at a wavelength around 150 nm. To provide a sterilising effect, the wavelength must be less than 365 nm and is preferably in the UVC band, between about 100 nm to 280 nm. Figures 6 to 8 show various views of another embodiment of a housing main part 108 for use in a second embodiment of uv knife sterilising system, and which would be removeably connected to the same housing second part 14 as in the first embodiment 1 . In this detailed description, reference numerals in the drawings for features of the second embodiment which correspond with those of the first embodiment, are those of the first embodiment incremented by 100.

In both embodiments, the uv light source 13 is configured to illuminate the cavity 12, 1 12 with uv light for sterilisation of one or more knives 2, 3, 102, 103 within the cavity. The apertures are provided in one side or face 6, 106 of the housing, and preferably the housing is oriented with this face being an upper-most or top side. Any convenient means may be used to orient and secure the cabinet in the workplace, and in this example the main part of the housing 8, 108 has a mounting bracket 16, 1 16 provided along one upper edge of the top face with through holes 18, 1 18 by which the housing main part may be screwed to a supporting surface, for example a wall (not shown). The particular form of mounting of the knife sterilising apparatus is not central to the invention, however, the invention provides the greatest convenience when the housing main part is oriented so that knives may be inserted into and withdrawn from the apertures along a substantially vertical axis.

The apertures are arranged in side-by-side pairs, in this example numbered: (4, 5), (4', 5'), (104, 105), (104', 105). Each aperture provides a corresponding passage 20, 120 for the knife blade and handle to be inserted into and then withdrawn from the housing interior. The aperture pairs are spaced apart in a direction that is substantially perpendicular to a direction of illumination from the uv light source. Each knife 2, 3, 102, 103 will have a handle 22 and a blade 23. A shoulder 27 will be provided between the handle and blade, most commonly by an end surface of the handle, although other types of shoulder such as a bolster on the blade (not illustrated) may alternatively be provided.

The handles and/or blades preferably have a cross section such that the knife can only be inserted into an aperture with the plane of the blade 23 in one of two orientations, 180° apart. Therefore, it is preferred if the apertures are sized to match the knives, and in the second embodiment, the housing upper face 106 is provided by a removable block 15 in which the apertures 104, 105, 104', 105' are provided. The knife sterilising apparatus may therefore comprise a set of blocks adapted for different sets of knives have differently sized handles 22 and blades 23. The apertures may be rectangular, as illustrated, or any other suitable shape.

In contrast, the first embodiment 1 has apertures 4, 5, 4', 5' each of which is provided by a hole in a stainless steel upper plate of the main housing portion, this hole having a skirt 26 which extends into the sterilising cavity 12. The purpose of the skirt is both to help guide the knife 2, 3 into the cavity during insertion blade-first, and to provide a shield to uv light, so that less uv light escapes from the cavity. In the second embodiment, the block 15 has a thickness 129 comparable with a length 29 of this skirt, for the same reasons. Both structures can therefore be regarded as channels 26, 126 through the outer wall of the housing. Preferably, the channel is at least 10 mm in length along an insertion direction (36), and most preferably between 20 mm and 30 mm, but in any case no more than about 50 mm. The reason the length of the channel should not be too long, is that it is desirable if a portion of the handle closest to the blade is also sterilised. Preferably at least half, and most preferably substantially all of the length of the handle 22 is exposed to uv light within the cavity to provide sterilising to parts of handle extending away from the blade.

In both embodiments, the length of the handle and the length of the channel 26, 126, is such that a butt end 24 of the handle is held within the skirt or block, so that the skirt or block guides the handle out of the aperture when the knife is ejected blade-last from the sterilising cavity, as explained below. Most preferably, the butt end is fully received within the channel, so that the butt end does not protrude out from the channel, when the knife is fully inserted. A first knife can then only be conveniently retrieved by inserting a second knife in the other channel, which causes at least the butt end 24 of the handle of the first knife to be ejected out from the channel 26, 126.

The knife sterilising cabinet provides for each aperture an associated blade guide within the housing or cavity for guiding the movement of a knife blade, and preferably also the handle. Part of this function is provided by each aperture and its corresponding skirt or block. Each blade is also guided by a funnel 28, 128 that is aligned with and faces upwardly towards a corresponding aperture. In these examples, the funnel is V-shaped with a pair of opposite inwardly facing guide surfaces 30, 130 which lead to a blade slot 32, 132 for receiving and engaging with the blade. Therefore, a tip 25 of each blade will, in general come into contact with one or another of the inwardly tapering surfaces 30, 130 and thence be guided to the slot 32, 132 or may sometimes align directly with the slot as the knife is being inserted into the sterilising cavity 12, 1 12. The skilled person will appreciate that other suitable shapes of funnel may provide a similar effect in guiding the blade into the slot 32 132. The funnels 28, 128 may be of a plastics material, such as nylon, to avoid blunting of the knife blades during insertion and removal. The blade guide function in these examples is therefore provided by the apertures, channels, funnels and slots, in combination. The skilled person will appreciate that other mechanical arrangements may provide a similar aligning effect, such that movement of the blade is guided towards the abutment during insertion and removal of the knife.

Inside the sterilising cavity is a pair of carriages 34, 34', 134, 134' consisting of a first carriage 34, 134 and a second carriage 34', 134'. Each carriage is moveable along opposite insertion (or first) and withdrawal (or second) directions 36, 36', 136, 136' relatively away from and towards a corresponding one of the apertures. Each carriage carries an abutment 38, 138 for making abutting contact with the corresponding shoulder 27 of the knife during the guided insertion of the blade 23. In this example, the abutment is provided either by the inwardly facing guide surfaces 30, 130 of the funnel, as illustrated, or by an upper edge 31 , 131 of the funnel.

The pair of carriages 34, 34', 134, 134' are interlinked whereby, in use, movement of the first one of the carriages, for example the first carriage 34, 134, in the first direction 36, 136 caused by the abutting contact during insertion of a first one of the knives through a corresponding aperture, causes movement of the second carriage, for example the second carriage 34', 134' in the second direction 36' 136', whereby a second one of the knives previously inserted into the other aperture is moved outwards from that aperture to assist removal of the second knife from the second aperture. The carriage therefore provides a see-saw like effect in the opposite movement of the knives.

In these examples, the pair of carriages is interlinked by a mechanical linkage that involves no external power source. Therefore, the mechanical linkage is passive, whereby movement of one carriage in the first direction drives the movement of the other carriage in the second direction.

The mechanical linkage comprises a wire linkage 40, 140 between the carriages 34, 34', 134, 134'. The wire linkage comprises a first portion 41 , 141 and a second portion 42, 142 the first portion extending away from a first one of the carriages 34, 134 substantially in the second direction 36', 136' and the second portion 42, 142 extending away from the second carriage substantially in the second direction 36', 136'. The first and second portions are linked together by a third portion 43, 143 of the wire linkage, the third portion extending around a loop provided by a wire track between the first and second portions of the wire linkage. In these examples, the wire track is provided by a tubular guide 44, 144.

Each carriage is movable along a guide rail, which in these example is provided by a rod 46, 146 that extends between opposite surfaces within the housing. In the first embodiment 1 , these opposite surfaces are the inner surfaces 48, 49 of the main housing itself. In the second embodiment, these surfaces 148, 149 are provided by end brackets 51 , 52 of a carriage module 50 that is removeably affixed to a mounting plate 53 proximate an upper end of the main housing portion 108. Each carriage comprises at least one sleeve that is slideably engaged with the rod. In the first embodiment 1 , there is one such sleeve 54, and in the second embodiment there two sleeves 154, 154', spaced apart along the length of the rod 146. In both embodiments, the first and second wire portions 41 , 42, 141 , 142 are attached to one of the sleeves.

In both cases, the sleeve 54, 154, 154' and guide rod are both cylindrical. Preferably, each carriage comprises an arm 56, 156 that extends between the corresponding guide rod 46, 146 and funnel 28, 128. In the first embodiment, the arm 56 extends substantially at right angles to the first and second directions 36, 36'. The arrangement is such that the guide rod is arranged with respect to the uv light source 13 such that the guide rod does not cast a shadow on the corresponding one of the blades when inserted.

The shadow cast by other components, such as the arms or funnels should ideally be minimised. A more even uv light distribution on the external surfaces of each blade is facilitated by the orientation of the blades, which is with the broad sides oriented substantially at right angles to the uv light projection direction from the light source, and by forming the interior surfaces of the housing in a reflective material, which in this example is mirror-finish stainless steel sheets. All surfaces in close proximity with the knife blade, particularly the funnel and adjacent carriage components, are provided in polished stainless steel, also to reflect uv light. Multiple reflections within the cavity then help to ensure that all surfaces of the knife blades, as well as, preferably, portions of the handles proximate the blades, are bathed in sterilising uv light.

Although not illustrated, the sleeves may comprise a low-friction bushing.

A safety micro-switch may be used to ensure that the lamps switch off when the housing second portion is removed from the main housing portion. An alternative safety cut-off is used in the illustrated embodiments, both of which have a magnet 58, 158 in the main housing portion, proximate to the depth at which the second housing portion slots into engagement within the open side of the main housing. The housing second portion then has a magnetic sensor 60, for example a reed switch or Hall effect sensor which detects the presence of the magnet when the two portions of the housing are connected together, for example by latches 61 , 62 as illustrated in Figure 1 . The sensor may be mounted permanently to an internal wall surface 63 within the second housing portion. When the housing portions are separated, the sensor sends a signal to the power supply ballast 59 when then cuts the power to the uv lamps.

In the first embodiment, the magnet 58 is mounted permanently to the internal wall surface 48 of the main housing portion top side 6. In the second embodiment, the magnet 158 is incorporated in the removable top face block 15, which has the advantage that if the top face block 15 is be removed for cleaning or to be replaced with a different block having different sized apertures (for example, suitable for differently dimensioned knife handles), then the uv light is powered off immediately the block 15 is removed. The magnet 158 may be accommodated in a recess in the end face of the block 15, as illustrated in Figure 9. In another arrangement (not illustrated), one or more cylindrical magnets may be accommodated in a blind bore that extends from a side face of the block 15 and runs parallel to the end face. The bore is sealed by a plastic grub screw.

For ease of use it is preferred if the top face block 15 rests loosely inside a matching recess 64 at the top end of the housing main portion 108. The top face block 15 and the recess 64 may be suitably shaped so that the top face block 15 can be seated only one way round in the recess 64, for example by adding lips to one, two or three of the sides of the block 15 and shaping the periphery of the recess 64 to accommodate the lips. This ensures that the magnet 158 is in the correct position to activate the sensor 60 when the top face block 15 is fitted.

Also to help with cleaning, the housing main portion 8, 108 has in a lower face 66, 166 a drain aperture 67, 167. The drain aperture is optional and may be omitted in some embodiments. One side face 68, 168 also has a window 69, 169, shielded by uv blocking material, for example polycarbonate, which will glow with visible light, some of which will be emitted by the uv-light source. The window 69, 169 need not be slit-shaped, as illustrated, and could instead be circular or have any other suitable shape. Figure 10 shows a carriage module 250 of a sterilising cabinet according to a third embodiment of the invention, with a pair of knives 202, 203 inserted into the carriage module 250. The carriage module 250 of this third embodiment can fitted into a housing main part 108 as described above with reference to the second embodiment. The carriage module 250 is generally similar to the carriage module 50 described above with reference to Figures 7 and 8, and only the differences will be described in detail. Reference numerals in Figure 10 for features of the third embodiment which correspond to features of the second embodiment are those of the second embodiment incremented by 100.

The carriage module 250 of Figure 10 differs from the carriage module 50 of the second embodiment in that each carriage 234, 234' includes a first funnel 228 and a second funnel 228a arranged below the first funnel 228.

The blade slot 232a of the second funnel 228a of each carriage 234, 234' is aligned beneath the blade slot 232 of the first funnel 228, so that the second funnel 228a provides a further guide for the respective knife blade 23. In particular, the second funnels 228a help to keep the knives 202, 203 in a vertical orientation as they are inserted into and removed from the carriage 234, 234' in use.

Each carriage 234, 234' is moveable along a respective pair of guide rails. Each rail is in the form of a guide rod 246. The rods 264 extend between opposite surface 248, 249 provided by end brackets 251 , 252 of the carriage module. Each carriage 234, 234' includes a pair of sleeves 254 that are slidably engaged with the respective pair of rods 246. The sleeves 254 extend between the top funnel 232 and the bottom funnel 232a of each carriage 234, 234', and each of the sleeves 254 of each carriage 234, 234' is connected by a side panel 255 of the carriage. A nylon bushing (not visible) is retained in each end of each of the sleeves 254 for engagement with the corresponding rod 246.

Although not shown in Figure 10, a mechanical linkage is provided to interlink the carriages 234, 234'. The linkage is as described above and operates to move one carriage 234 in the first (withdrawal) direction when the other carriage 234' is moved in the second direction.

As in the second embodiment of the invention, in the third embodiment more than one carriage module 250 may be provided.

Use of the knife sterilising cabinet described above may result in a halving, or better, of running costs as compared with hot water sterilising equipment, owning to reduced energy costs. The knives are not significantly heated in the process, which means that workers can more easily handle the knives after sterilising.

Normally, workers may partially clean the knives in a warm water dip prior to insertion in the knife sterilising cabinet. As it takes, typically no more than 10 seconds for uv light to sterilise the knives, a worker using at least two knives can switch knives without having to be concerned that insufficient time has elapsed.

Once one knife is fully inserted, then the other knife is automatically raised into a position for the handle to be securely grasped and pulled out from the aperture of the knife sterilising cabinet.

The invention therefore provides a convenient and economical knife sterilising cabinet for sterilising knives, and also a knife sterilising system, comprising a knife sterilising cabinet and at least two knives each having a handle, a blade and a shoulder between the handle and the blade.

Claims

1 . A knife sterilising cabinet for sterilising knives, said knives each having a handle, a blade and a shoulder between the handle and the blade, said cabinet comprising:

a housing;

a cavity within the housing;

- for the, or each pair of apertures, a pair of carriages within the cavity, said pair of carriages consisting of a first carriage and a second carriage, and each carriage being moveable along opposite first and second directions relatively away from and towards a corresponding aperture and each carriage carrying an abutment for making abutting contact with a corresponding shoulder during said guided movement of said blade;

wherein for each pair of carriages said first and second carriages are interlinked whereby, in use, movement of the first carriage in the first direction caused by said abutting contact during insertion of a first one of said knives through the first aperture causes movement of the second carriage in the second direction, such that a second one of said knives previously inserted into the second aperture is moved outwards from the second aperture to assist removal of the second knife from the second aperture.

2. A knife sterilising cabinet as claimed in Claim 1 , in which each blade guide comprises a channel aligned with a corresponding one of said apertures, each channel being configured to engage with a handle of a corresponding knife to guide movement of said blade during said insertion and removal of said knife.

3. A knife sterilising cabinet as claimed in Claim 1 or Claim 2, in which each blade guide comprises a slot carried by the carriage, each slot being configured to engage with a blade of a corresponding knife to guide movement of said blade during said insertion and removal of said knife.

4. A knife sterilising cabinet as claimed in Claim 3, in which each blade guide comprises a funnel carried by the carriage, each funnel having a mouth that faces towards a corresponding one of said apertures for receiving and guiding a tip of said blade into said slot.

5. A knife sterilising cabinet as claimed in Claim 4, in which each abutment is provided by an inner surface of said funnel.

6. A knife sterilising cabinet as claimed in one of Claims 3 to 5, in which each abutment is provided by a surface that extends away from said slot.

7. A knife sterilising cabinet as claimed in any of Claims 3 to 6, in which each blade guide comprises first and second slots carried by the carriage, each slot being configured to engage with a blade of a corresponding knife to guide movement of said blade during said insertion and removal of said knife, the second slot being spaced from the first slot along the first direction.

8. A knife sterilising cabinet as claimed in Claim 7 when dependent on Claim 4, in which each slot is associated with a respective funnel carried by the carriage, each funnel having a mouth that faces towards a corresponding one of said apertures for receiving and guiding a tip of said blade into the corresponding slot.

9. A knife sterilising cabinet as claimed in Claim 8, in which each abutment is provided by an inner surface of the funnel associated with the first slot.

10. A knife sterilising cabinet as claimed in any preceding claim, in which each carriage is movable along a guide rail that extends between opposite surfaces within said housing.

1 1 . A knife sterilising cabinet as claimed in Claim 10, in which said opposite surfaces are provided by opposite walls of said housing.

12. A knife sterilising cabinet as claimed in Claim 10 or Claim 1 1 , in which the carriage comprises a sleeve that is slidably engaged with the guide rail.

13. A knife sterilising cabinet as claimed in Claim 12, in which the sleeve and guide rail are both cylindrical.

14. A knife sterilising cabinet as claimed in any one of Claims 10 to 13, when dependent from Claim 4, in which each carriage comprises an arm that extends between the corresponding guide rail and funnel.

15. A knife sterilising cabinet as claimed in Claim 14, in which each arm extends substantially at right angles to said first and second directions.

16. A knife sterilising cabinet as claimed in any one of Claims 10 to 15, in which the guide rail is arranged with respect to said uv light such that the guide rail does not cast a shadow on the corresponding one of said blades when inserted.

17. A knife sterilising cabinet as claimed in any preceding claim, in which said pair of carriages are interlinked by a mechanical linkage.

18. A knife sterilising cabinet as claimed in Claim 17, in which the mechanical linkage is passive, whereby movement of one carriage in said first direction drives the movement of the other carriage in the second direction.

19. A knife sterilising cabinet as claimed in Claim 17 or Claim 18, in which the mechanical linkage comprises a wire linkage between said carriages.

20. A knife sterilising cabinet as claimed in Claim 19, in which the wire linkage comprises a first portion and a second portion, the first portion extending away from the first carriage substantially in the second direction and the second portion extending away from the second carriage substantially in the second direction, said first and second portions being linked together by a third portion of the wire linkage, the third portion extending around a loop provided by a wire track between said first and second portions of the wire linkage.

21 . A knife sterilising cabinet as claimed in Claim 20, in which the wire track comprises a tubular guide.

22. A knife sterilising cabinet as claimed in Claim 20, in which the wire track comprises a roller guide.

23. A knife sterilising cabinet as claimed in any one of Claims 20 to 22, in which the wire track guides said third portion around an arc of substantially 180°.

24. A knife sterilising cabinet as claimed in any preceding claim, in which said uv light source is configured to project uv light in a projection direction towards said knife blades, and the blade guides are configured to orient said blades substantially parallel with one another with a narrow edge of said blades facing towards said projection direction.

25. A knife sterilising cabinet as claimed in any preceding claim, in which said cabinet has interior reflective surfaces whereby broad surfaces of said blades are illuminated substantially by uv light reflected from said surfaces and not directly from said projected uv light.

26. A knife sterilising cabinet as claimed in any preceding claim, wherein the entire knife blade is received within the cavity for illumination with uv light when the knife has been inserted through an aperture and the respective carriage has been moved in the first direction.

27. A knife sterilising cabinet as claimed in Claim 26, wherein at least a part of the knife handle is also received within the cavity for illumination with uv light when the knife has been inserted through an aperture and the respective carriage has been moved in the first direction.

28. A knife sterilising system, comprising a knife sterilising cabinet, the knife sterilising cabinet being as claimed in any preceding claim, and at least two knives including a first knife and a second knife, each knife having a handle, a blade and a shoulder between the handle and the blade, wherein said knives are each shaped to be received blade-first by said first and second apertures and to be engaged by said first and second blade guides to guide movement of said blades during said insertion and removal of said knives, whereby, in use, said blades when inserted into the cavity are sterilised by ultra-violet (uv) light within the cavity, and the blade handle of each one of said inserted knives is ejected from one of said first and second apertures upon subsequent insertion of another one of said first and second knives into the other one of said first and second apertures.

29. A knife sterilising system as claimed in Claim 28, in which the length of each blade handle is such that the length of each knife handle is fully received within said aperture when the knife is inserted into said aperture.