The invention to which this application relates is to apparatus for dispensing packaging material and, in particular, although not necessarily exclusively, to the dispensing of a packaging material in a form which it is intended to be expanded in its area and/ or volume when being dispensed.

Increasingly, the use of plastics-based packaging material is discouraged due to the environmental concerns about the recyclability of plastic material and the amount of plastics material which reaches landfill sites and/ or creates hazardous waste. It is known to provide an alternative form of packaging material which is manufactured from new and/or recycled material and/or a combination of the same in for example, the form of card and/ or paper-based products. One form of recyclable packaging material which is used typically comprises at least one sheet of the material and in which a plurality of slits are formed. Each of the slits may be provided with a shallow arrow shape or another suitable shape and the slits are arranged in rows, with each row located along an axis and the axes of the rows are respectively substantially parallel. Furthermore the axes are typically located such that they are perpendicular to the direction of movement of the leading edge of the packaging material from a supply roll of said material. Typically the slits in one row are located so as to be offset to the slits in adjacent rows with a pattern which repeats across and along the said sheet material.

The slits, the shape of the same and pattern of the location of the same on the sheet material is all controlled so as to allow the packaging envelope of the material to be expanded from a first condition in which the slits are substantially closed and the sheet material is in a relaxed substantially two dimensional form and in which the sheet material is located on the supply roll, to a second condition in which the slits are moved to an opened position by the application of stretching forces to the sheet material to expand the same in one or more directions so as to expand the size of the slits, and hence expand the area and/ or volume of the packaging material to move the same into an enlarged three dimensional form so that the packaging material provides a greater cushioning effect when it is used to surround and package an article or articles. It will therefore be appreciated that this arrangement of packaging for an article, is completely recyclable and therefore increases the attractiveness of use of this form of packaging material whilst, at the same time, ensuring that the protection of the article in question can still be achieved.

This form of packaging material has been known for some considerable time and is typically the supply roll fits into a bespoke dispensing apparatus which means that, as the leading edge of the sheet material is pulled away from the roll there is sufficient resistance so as to cause the packaging material to also be moved to the second, expanded, condition whilst, simultaneously, allowing the dispensing of the required length of the sheet material from the roll to be achieved by a person pulling manually on a portion of the sheet material which has already been dispensed from the roll.

Furthermore, the apparatus can be used to dispense a single sheet of material or in certain embodiments, may be used to dispense two or more overlapping sheets of materials simultaneously.

One known form of dispensing apparatus includes a bar which is provided to be selectively positioned by the user onto the core of the supply roll and about which the sheet material is wound so as provide a user selected level of resistance to the rotation of the core with respect to the dispensing apparatus and hence controls the dispensing of the sheet material from the roll so that the dispensing resistance is sufficient to cause expansion of the sheet material to the second condition whilst, at the same time, ensuring that the roll can still be rotated by the user. In practice it is found that this can lead to error in that the level of resistance is reliant upon the user making the correct selection and, if they don’t, and the resistance to the roll rotation is too light, then the sheet material is dispensed without being expanded and subsequent expansion can be difficult to achieve in a uniform manner or, if the resistance to rotation is too great, then the sheet material is not expanded at all or is dispensed at a very slow rate which therefore acts as a bottieneck in the packing process. It is also found that the level of resistance required to be applied to the core of the roll in order to maintain a substantially uniform dispensing rate and expansion performance changes as the amount of the said sheet material remaining on the roll changes from a full roll to an empty supply roll in which only the core remains. Typically, the length of the portion of the sheet material which is dispensed at any given time, may alter depending on the particular article which is to be wrapped in the packaging material and/ or the size of the container in which the article and/ or packaging material is to be placed. Furthermore, the type of item which is to be packaged may define the length of the portion of sheet material required to provide sufficient protection to prevent damage of the packaged article during transit. For example, an article which is formed of glass will typically require more packaging material to be used than an article formed of wood.

Cutting of the sheet material to form the required length of the dispensed portion is required and, given that the sheet material will be in an at least partially expanded form at the location of cutting, it is found that in practice, it is difficult to obtain an efficient, uniform and quick cut. This can cause time delay in the packaging of articles using the sheet material and can also cause rough or indefinite cuts to be created which may require repeated cuts to be performed. Typically, the cut is conventionally achieved by the operator using a knife or scissors which in itself can be dangerous.

It is therefore an aim of the present invention to provide a dispensing apparatus of a form which is particularly suited for dispensing an expandable sheet material in a form which allows the dispensing to be performed reliably and efficiently. It is a further aim to ensure that the sheet material is dispensed in a manner which allows the same to expanded whilst also ensuring that the rate of dispensation means that the apparatus does not form a bottieneck in the process of packing items. It is a yet further aim to provide dispensing apparatus in a form which allows a substantially uniform dispensing rate to be achieved throughout the dispensing of sheet material from a supply roll as it changes from full to empty conditions.

A further aim of the present invention is to provide a means for forming a cut line across a portion of sheet material which is typically perpendicular with respect to the direction of dispensing the sheet material supply and to do so in a manner which provides a clean, efficient and easily repeatable cuts to be achieved to define successive portions of dispensed sheet material. In a first aspect of the invention, there is provided dispensing apparatus for a packaging sheet material formed from one or more layers, said dispensing apparatus including first and second spaced apart end walls defining an exit path for sheet material dispensed from a supply roll of said sheet material by rotation of the same, said supply roll supported in location between said first and second end walls and a braking assembly is provided to provide resistance to rotation of said roll wherein said braking assembly includes a braking member arranged to contact locating means for said supply roll and a control member, said control member provided to be in contact with an external surface of the said roll and the position of said control member determines, via a biasing means, the level of braking force applied by the braking member to the rotation of the supply roll when dispensing sheet material therefrom.

Typically the said sheet material is an expandable sheet material and the said expansion is to be at least partially achieved during the dispensing of the sheet material from the said roll.

In one embodiment the said braking assembly braking member is located at, or adjacent to, an end of the supply roll.

Typically the relative position of the control member and the braking member and biasing force applied to the braking member changes automatically with respect to the change in the radius length of the supply roll from a full to an empty condition so as to ensure that adjustment of the torque and hence braking force occurs during the change in condition of the supply roll from full to empty due to sheet material being disposed therefrom and thereby ensures a substantially uniform manual performance of the dispensing and expansion of the sheet material from the supply roll between full and empty conditions as a result of the variation in resistance applied to rotation of the supply roll as it changes from full to empty conditions.

Typically the longitudinal axis of the said supply roll is substantially parallel with the pivot axis of the control member as it pivots to maintain contact with the external surface of the supply roll. In one embodiment a portion of the core of the supply roll extends at least to the side of the sheet material at which the braking assembly is located.

In one embodiment the said external surface with which the control member contacts is the external surface of the outer layer of the sheet material which is provided to be dispensed from the supply roll. In another embodiment the core of the supply roll is longer than the width of the sheet material and the said control member contacts with an external surface of the said core.

In one embodiment the braking force applied reduces as the condition of the supply roll changes from full to empty.

Typically the braking force which is applied is selected to be such that the force required to be applied to the sheet material when dispensing of the sheet material from the supply roll and the degree of expansion of the sheet material from the first to a second condition is substantially uniform throughout the dispensing of sheet material from the supply roll and substantially matches the dispensing requirements of the user of the dispensing apparatus.

In one embodiment the said braking member is in the form of a shoe of a material such as rubber or other gripping material and the locating means with which the same engages typically includes a disc or annular shaped member which is mounted with it’s centre axis substantially in-line with the longitudinal axis of said supply roll of sheet material.

Typically each of the locating means includes a portion which engages with the core of the supply roll and so the said location means portions and supply roll rotate together as one integral unit when fitted. This in turn allows the braking force applied to the disc or annular shaped member to be passed to act as a braking force on the rotation of the supply roll as the sheet material is dispensed and expanded.

In one embodiment the said supply roll of sheet material is located on the core which typically spans the said end walls and is located thereon. In one embodiment the said sheet material is formed of one or more layers through which a series of spaced apart slits are formed and said slits are opened and expanded during the dispensing of the sheet material so as to allow the area and/ or volume of the sheet material to increase to a form suitable for use as a packing material. In one embodiment the sheet material is of a form described in the applicant’s co-pending application number GB 2015669.1, the contents of which are incorporated herein by reference.

Typically, once a full supply roll is installed in position in the said apparatus and the control member positioned with respect to the same, the subsequent provision of the braking force applied by the braking member and change in the level of braking force applied to the supply roll during the dispensing of sheet material therefrom until an empty condition is reached, occurs automatically. Thus, in accordance with the invention, there is no need for user interaction with the braking assembly or user selection of the braking force and hence resistance to the rotation of the supply roll during the dispensing of the sheet material therefrom.

Typically the biasing means which acts on the braking member is a spring, and in one embodiment the spring is mounted on an end wall of the apparatus, typically the end wall which is adjacent the braking member.

Typically the control member can be moved between a disengaged position to allow the full roll to be introduced and the empty supply roll core to be removed, and an engaged position in contact with said external surface.

In one embodiment the braking assembly biasing means and the tension applied thereby can be adjusted and, once adjusted, the change in tension occurs with reference to the amount of the sheet material on the core of the supply roll at that time.

In one embodiment the adjustment may be made with respect to the specific type of the sheet material which is provided on the supply roll located with the apparatus at that time.

In one embodiment the said braking assembly, end walls and support means for the supply roll are provided as a container or in another embodiment as a frame. In one embodiment a braking assembly is located at each end of the supply roll. In another embodiment a braking member is provided to act at each end of the roll and the said braking members are connected to and react to the condition of a common control member.

In a further aspect of the invention there is provided a method of dispensing a packaging sheet material formed from one or more layers, said method including the steps of providing a dispensing apparatus including first and second, spaced apart, end walls defining an exit path for the said sheet material dispensed, placing a supply roll of said sheet material in location between said first and second end walls and retaining the same in position via first and second locating means which locate and engage with respective ends of a core of said supply roll, rotating the supply roll by pulling a leading edge of the sheet material along said exit path and away from said supply roll and providing a brake assembly to provide resistance to rotation of said supply roll wherein said brake assembly includes a braking member located to exert a braking force on rotation of said roll, and a control member, positioning said control member to contact with an external surface of the said supply roll such that the position of said control member determines, via a biasing means, the level of braking force applied by the braking member to the rotation of the supply roll when dispensing sheet material therefrom.

In one embodiment the apparatus and method includes a cutting assembly including a moveable blade to separate a portion of sheet material from the said supply roll by moving the cutting assembly along guide means of the apparatus. Typically the cutting assembly can be used in the same apparatus as, and in conjunction with the braking assembly or the braking and cutting assemblies can be used independently.

In a further aspect of the invention there is provided a dispensing apparatus for a packaging sheet material formed from one or more layers, said dispensing apparatus including first and second spaced apart end walls defining an exit path for sheet material dispensed from a supply roll of said sheet material by rotation of the same, said supply roll supported in location between said first and second end walls and wherein the apparatus includes a cutting assembly which is movable along a guide means cut through the sheet material and separate a portion of dispensed sheet material from said supply roll. In one embodiment, the cutting assembly is mounted on a guide means of the apparatus and the guide means has a longitudinal axis which is substantially perpendicular to the direction of movement of the free end of the sheet material from the dispensing apparatus.

Typically, the said cutting assembly is located on the guide means so as to be slidably moveable therealong.

In one embodiment, the apparatus further includes a cutting mat which is located on the opposing side of the sheet material from the cutting assembly.

In one embodiment, the cutting mat underlies the sheet material and the cutting assembly is located above the sheet material. Typically, the cutting blade, extends from the top-side of the sheet material and through the same to cut and separate the said portion of sheet material.

Typically, the sheet material includes a series of slits formed therein and the sheet material supply is held in the dispensing apparatus in a compressed state, typically, as a supply roll of the sheet material.

Typically, the force exerted on the free end is such as to allow the required length of sheet material to be dispensed therefrom and, once this has been achieved, the exertion force on the sheet material may be released and the cutting assembly moved across the sheet material so as to cut through and release the said portion of sheet material for subsequent use in packaging.

In one embodiment, the blade is provided to be rotatable and the rotation of the blade occurs as a result of the movement of the cutting assembly along the guide means.

In one embodiment, the cutting assembly includes a housing in which the cutting blade is mounted and said housing is connected to bearings which engage with the guide means to allow the cutting assembly to slide therealong. In one embodiment, at least one portion of the housing is selectively removable so as to allow access to be gained to the cutting blade to allow the same to be replaced and/ or cleaned.

In one embodiment, the cutting assembly can be moved in opposing directions along the guide means and preferably, movement of the cutting assembly in a first direction, allows the cutting through of the sheet material and release of a portion and then once a further portion has been extended from the dispensing apparatus, the movement of the cutting assembly in the opposing direction, causes the cutting through of the sheet material to define said subsequent portion of sheet material. This therefore allows a relatively fast cutting action and formation of portions or packaging material which, in turn, improves throughput of the packaging process of items.

Typically the apparatus includes tensioning means which apply a resistive force to the movement of the supply roll of sheet material.

In a further aspect of the invention, there is provided a method of dispensing a sheet material from a dispensing apparatus, said method comprising the provision of a roll of said sheet material supply, extending a free end of said sheet material from the dispensing apparatus, providing a cutting assembly on a guide means and moving the cutting assembly to a position on the guide means so as to allow free movement of the sheet material from the dispensing apparatus by exerting a pulling force on the free end of the sheet material to extend a portion of the sheet material from the apparatus and wherein the cutting assembly is moved along the said guide means so as to allow a cutting blade of the assembly to cut across and through the sheet material and hence attach the said portion of the sheet material from the sheet material supply.

Typically, the steps of extending the free end of the sheet material from the dispensing apparatus, and movement of the cutting assembly along the said guide means are repeated so as to allow successive portions of the sheet material to be defined. Thus, in accordance with the invention, the advantages of providing a substantially uniform dispensing condition is achieved and altered automatically as the condition of the sheet material roll changes from a full to an empty condition, and there can be provided means to allow the efficient separation of successive portions of the sheet material.

Specific embodiments of the invention are now described with reference to the accompanying drawings; wherein

Figures la-d illustrate one form of sheet material to which the application relates in a first, relaxed, condition and a second, expanded condition respectively;

Figures 2a-e illustrate on embodiment of dispensing apparatus in accordance with the invention;

Figures 3a-b illustrate the loading of a roll of sheet material of the type shown in Figures la-d to the apparatus of Figures 2a-e;

Figures 4a-g illustrate the apparatus of the embodiment of Figures 2a-e with the full roll of sheet material located there with to be dispensed;

Figures 5a-b illustrate the braking assembly of the apparatus in one embodiment;

Figures 6a-b illustrate the manner in which the control member of the braking assembly alters as the roll changes between full and empty conditions;

Figures 7a-h illustrate use of dispensing apparatus in accordance with another embodiment including a cutting assembly;

Figures 8a-d illustrate a dispensing apparatus in accordance with one embodiment of the invention;

Figures 9a and b illustrate an example of replacement of the cutting blade of the cutting assembly. Referring firstly to Figures la-d, there is illustrated a packaging material 2 in accordance with a conventional form in which there is provided a sheet material formed of one or more layers and with opposing external surfaces 4 and 6. The sheet material has formed therein, a series of apertures in the form of slits 8 in a predefined pattern, with each of the slits provided in rows 9, each row with a longitudinal axes which are parallel and parallel to a general axis 10 which is perpendicular to the direction of movement 16 of the sheet material as will be explained. Furthermore, the slits 8 in a first row are offset along its longitudinal axis with respect to the location of the slits on the longitudinal axes of adjacent rows as shown in Figure Id which shows in detail a part of the sheet material 2 as shown in Figure la . In Figures la and Id it is shown that the sheet material may initially be provided as a packaging material supply in the first, relaxed, condition in which the slits 8 are closed and provided on a roll 12 and for use with the dispensing apparatus 14.

To use the packaging material a movement force is applied to the leading edge 18 of the sheet material in the direction of arrow 16 to draw the leading edge 18 from the roll and a retention force is created by the dispensing apparatus on the sheet material 2 which is sufficient to act to open the slits 8 due to the flexibility of the material, to open the same to form a series of substantially diamond or hexagon shaped apertures 8’ as shown towards the leading edge 18 in Figure la and in Figure lb, which shows the detailed part 20 of the packaging material in the expanded, second condition. Thus, in the second condition the area and volume of the sheet material 2 is increased so as to provide a three dimensional packaging material and provide a greater cushioning effect and coverage area for the packaging material when used to surround and package an article. It will be seen that the whole of the section of the sheet material which has been removed from the dispensing apparatus is expanded to the second condition of Figure lb, and Figure lc illustrates that the packaging material extends from a substantially thin section to have an increased depth so that the volume of the packaging material also increases. Typically, an appropriate sized section of the sheet material for the packaging of the one or more articles is cut-off from the roll 12 to provide a sufficient amount of the packaging material to enclose the article which is to be packaged and provide sufficient cushioning effect on the article so as to protect the article during the subsequent transportation of the same. Referring now to Figures 2a-e there is illustrated apparatus 24 in accordance with one embodiment of the invention. The apparatus includes first and second spaced apart end walls 26,28 which are spaced apart and retained by members 30, 32. The end walls have feet 34, 36, 38, 40 to allow the apparatus to be securely located on a support surface 42 and which may exert a gripping force on the said support surface so as to aid the retention of the apparatus in location during use. The said end walls define an exit path 46 for the dispensing and expanding of the sheet material from the apparatus as shown in Figure 2b

Mounting means 44 for a roll of the sheet material include a spindle 48, and at each end a location means 50, 52 is located. In this embodiment the location means 50 includes a cup portion 54 which is formed so as to be received in an end of the tubular core of the roll and exert a gripping force thereon. The location means 52 also includes a cup portion 54 which is received within the end of the core of the roll and also includes a disc 56 which is connected in a fixed relationship with the cup portion 54 and hence core of the roll when fitted thereto. The disc 56 acts as the interface with a braking assembly 58 which includes a braking member 60, biasing means 62 and control member 64 and which will be described in further detail subsequentiy.

Figures 3 a and b illustrate the manner in which a sheet material roll 70 which includes the core 72 and the quantity of rolled up sheet material 74 in an unexpanded form, is mounted on the apparatus. The roll 70 is moved onto the spindle 48 as indicated in the direction of arrow 76 such that the spindle passes along the interior of the core with location means 52 located at the end 78 and the cup portion 54 of the location means 50 is located in the end 80 of the core. The location means 50, 52 are then moved, along with the mounted roll 70 as indicated by arrows 82,84 so that the protruding ends of the spindle 48 are moved into the respective receiving slots 86,88 and then retained in that position by movement of the spool lock 68 as indicated by arrow 90 to overlie the slot entry 88 and thereby trap the end of the spindle 48 therein.

The apparatus is then loaded with the full roll 70 as shown in Figures 4a-g and the leading edge of the sheet material on the roll can then be gripped and moved in the direction 46 along the exit path so as to dispense the required length of sheet material required for a packaging operation and, at the same time expand the slits in the sheet material and expand the sheet material to a three dimensional form with increased volume and area. During the loading of the roll 70, the control member 64 will typically be moved to a disengaged position 64’ as shown in broken lines in Figure 4a so as to allow free movement of the roll into position. Once the roll is in position the control member is moved into position to contact the external surface 92 of the roll and the control member remains in contact as the roll is rotated to dispense material and as the distance between the external surface 92 of the roll from the core reduces as the material is dispensed from the roll and so the roll moves from the full position shown to an empty condition in which only the core remains and needs to be replaced.

The braking assembly 58 is shown in greater detail in Figures 5a and b and it can be seen how the control member 64 is located on the member 32 and pivotally moves around the longitudinal axis 94 of the same which is substantially parallel with the axis 96 of the spindle 46. The braking member 60 is mounted with respect to a base member 98 which is located on the end wall 28 and a gap 100 is defined between the base member 98 and the braking member 60 and the disc 56 is positioned such that a circular path of the disc always lies in the gap 100. The width of the gap 100 is determined by the relative position of the braking member 60 with respect to the base member 98 and the movement of the braking member is determined by the act of the biasing means 62 thereon and with which the braking member 60 is located. The action of the biasing member 62 is determined by the position of the control member 64 at that time and the control member is in contact with a location bracket 102 for the biasing means 62 which is coaxially mounted with the control member on the member 32 and the bracket is slidingly movable along the support member whilst being biased by the biasing means 62 towards contact with a sloped contact face 104 of the control member and to follow the same. The contact position between the contact face 104 and the bracket 102 is determined by the position of the control member and hence the position of the external face and hence amount of amount of sheet material on the roll at that time.

As shown with reference also to Figures 6a and 6b, when as shown in Figure 6a, the roll is full, the position of the contact member 64 on the external face 92 means that the same is over the centre of the member 32 and the position of the contact face 104 and bracket 102 on the support member 32 are such that the biasing means 62 closes the gap 100 and the braking member 60 is exerting a maximum braking force on the rotation of the disc 56, and hence the roll 70, during dispensing of the sheet material by pulling the leading edge 110 along the exit path 46 and hence there is sufficient retention on the rotation so as to cause the material to be dispensed and expanded.

When the roll 70 is nearly empty as shown in Figure 6b, the position of the control member 64 is still over centre of the member 32 and has pivoted further as indicated by arrow 108 by maintaining contact on the support surface 92 and, as a result the contact face 104 has rotated around the member 32 such that the bracket 102 has moved along the support member 32 in a direction away from the end wall 28 and so the force applied by the biasing means 62, which is moved by the bracket 102, on the braking member 60 is reduced and the gap 100 is opened so that the braking force has been reduced to a minimum braking force and hence the aim of automatically altering the braking force so as to achieve a reliable and substantially uniform dispensing and expansion of the sheet material throughout the change in the roll from full to empty conditions, is achieved.

The level of tension on the biasing means 62 before commencing operation of dispensing from a roll may be adjusted by using the control means 66 which alters the position of the biasing means 62.

Referring now to Figures 7a-h, and 8a-d there is illustrated another embodiment of dispensing apparatus 112 for use in the dispensing of sheet material 116 therefrom. The sheet material 116 is typically provided on a roll 114 as a sheet material supply and the roll is held on a core 118 to allow the same to be located with the side walls 120,122of the apparatus and to rotate about the longitudinal axis 124. A braking assembly 64 as previously described with respect to Figures 1-6 is again provided so as to allow the roll of sheet material to be held under tension and furthermore to be a substantially uniform tension regardless of the amount of sheet material held on the roll at that time, so as to provide a level of resistance to the dispensing of the sheet material 116 and so open the slits in the sheet material. Ffowever it should be noted that the cutting assembly as herein defined may be used to advantage on apparatus which is not provided with the braking assembly. The side walls of the apparatus are located on a base 128 and, at the dispensing side 130 of the base, there is provided a cutting mat 132 which may be formed of a rubber or similar absorbent material.

Also provided, are guide means 134 at the dispensing side of the apparatus and, on the guide means, there is mounted a cutting assembly 136 which is capable of being slid in a first direction 140 along the guide means and in a second, opposition direction 138 along the guide means. The cutting assembly typically includes a housing 142 in which there is mounted a cutting blade 144 and which is located so it is to extend towards and in touching contact with the cutting mat 142. The housing is located with bearing 146 which in turn are located with the guide means 134 so as to allow a relatively smooth sliding movement of the cutting assembly along the same. The housing is also provided in location with a handle 148 which is provided to be grasped by a user’s hand 150 as indicated in Figure 8c and so allow manual movement of the cutting assembly along the guide means to be achieved.

In operation, the cutting assembly 136 is first moved to a position such as that shown in Figure 8a and Figure 8b in which the same is offset to one side of the width X of the sheet material supply. This therefore prevents the cutting assembly from being an obstacle to the dispensing of the sheet material leading edge 150. In order to dispense the material, the leading edge 152 is grasped by an operator and as indicated in Figure 8c is pulled away from the roll in a direction 154 until a portion 156 of a required length of the packaging material has been extended away from the dispensing apparat. At the same time as exerting the force on the leading edge to pull the portion away from the dispensing apparatus, the slits which are formed in the sheet material, are expanded so as to bring the packaging material into a form for use in packaging.

Once the required length of the portion 156 has been pulled away from the apparatus, the cutting assembly 136 is then slidably moved across the sheet material in the appropriate direction 138 towards the opposing side as indicated in Figure 8a and, as it does so, the blade 144, as indicated in Figures 8c and d, will pass and cut through the sheet material 116 thereby leaving the portion 156 of the sheet material separated from the supply. The said portion 156 can then be removed and used for packaging purposes.

Typically, therefore a cut through of sheet material will be achieved for each pass of the cutting assembly, and thereby allows a relatively fast throughput and formation of portions of the sheet material.

Over time, it may be necessary to remove a blunt blade and replace the same and/ or to clean the blade and Figures 9a and b illustrate the housing 142 a release mechanism 158 in the form of a button which is biased towards an engaged position but which can be forced against the biased means to release a lock. This then allows the outer part 160 to be rotated and then disengaged from the remainder 162 of the housing and this results in access being gained to the blade 144 to allow the same to be cleaned and/ or replaced.