WO2008041000A2

WO2008041000A2 - Surface cleaning apparatus

Info

Publication number: WO2008041000A2
Application number: PCT/GB2007/003795
Authority: WO
Inventors: Sheila Hamilton; Charles Jonathan Kennett
Original assignee: Teknek Holdings Limited
Priority date: 2006-10-06
Filing date: 2007-10-05
Publication date: 2008-04-10
Also published as: WO2008041000B1; WO2008041000A3; GB0619754D0

Abstract

A surface cleaning apparatus adapted to control the positioning of a work- piece to be cleaned, the apparatus comprising a framework; spaced first and second work-piece supporting surfaces; a contact cleaning assembly positionable between said spaced supporting surfaces, the assembly adapted to receive a work-piece to be cleaned and being mountable on said framework and movable thereon; wherein the contact cleaning assembly is provided with first and second supporting members each adapted to support a portion of the respective supporting surfaces; and wherein movement of the contact cleaning assembly on the framework causes corresponding movements of the first and second supporting members to cause a complementary increase and decrease in the lengths of the respective work-piece supporting surfaces.

Description

Surface Cleaning Apparatus

This invention relates to surface cleaning apparatus and particularly, but not exclusively, to surface cleaning apparatus having a reduced footprint area and employing a cleaning roller and an adhesive roller for removing contamination and/or debris from a work-piece to be cleaned.

Surface cleaning apparatus employing cleaning and adhesive rollers is known. Such apparatus operates by providing the cleaning roller with a surface of relatively low tackiness that contacts an adhesive roller of relatively high tackiness, the respective rollers being arranged parallel to one another and contacting each other over substantially their entire length. As a web or sheet material (hereinafter referred to as a work piece) is conveyed over the surface of the cleaning roller, debris on the work piece is removed. In order that the cleaning roller remains effective over a period of time, the removed debris is transferred to, and retained by, the adhesive roller during rotation of the respective rollers. Commonly, the work piece to be cleaned is conveyed through the nip of at least two opposed rollers, at least one of which is a cleaning roller. Opposed pairs of cleaning rollers may be used to allow simultaneous removal of particulate material from the opposing surfaces of the work piece.

A work-piece to be cleaned is generally supported in a horizontal orientation and conveyed from a pre-cleaning position which is upstream of the nip of the cleaning rollers to an exit position which is downstream of the nip of the cleaning rollers. Accordingly, a particular problem arises in the cleaning of larger work-pieces which require larger support surfaces both upstream and downstream of the nip of the cleaning rollers. Indeed, the longer the work-piece to be cleaned, the longer the respective support surfaces must be and, consequently, the larger the overall width and footprint of the cleaning apparatus.

Whilst such cleaning apparatus can bring significant yield improvements, many users or potential users have space constraints which place a limit on the size or amount of support equipment that they can accommodate. Maximisation of floor-space efficiency is therefore highly desirable in the contact cleaning industry.

According to a first aspect of the present invention there is provided surface cleaning apparatus adapted to control the positioning of a work- piece to be cleaned, the apparatus comprising: a framework; spaced first and second work-piece supporting surfaces; a contact cleaning assembly positionable between said spaced supporting surfaces, the assembly adapted to receive a work-piece to be cleaned and being mountable on said framework and movable thereon; wherein the contact cleaning assembly is provided with first and second supporting members each adapted to support a portion of the respective supporting surfaces; and wherein movement of the contact cleaning assembly on the framework causes corresponding movements of the first and second supporting members to cause a complementary increase and decrease in the lengths of the respective work-piece supporting surfaces.

Optionally, the first and second work-piece supporting surfaces are provided on supporting belts adapted such that at least a portion of each belt is maintained in a stationary position relative to the framework during the movement of the contact cleaning assembly. Alternatively, the first and second work-piece supporting surfaces are provided on supporting belts adapted such that each belt is conveyed in a direction opposite to that of the contact cleaning assembly during the movement of the contact cleaning assembly.

Preferably, the supporting belts are each defined by a series of spaced parallel belts.

Alternatively, the supporting belts are each comprised of a unitary web of material.

Preferably, the respective supporting belts are connectable together.

Most preferably, the respective supporting belts are comprised of a continuous piece of material.

Optionally, the continuous piece of material comprises an endless loop.

Preferably, the first and second supporting members are rollers, each adapted to support the underside of the respective supporting belts.

Preferably, movement of the contact cleaning assembly is adapted to cause a corresponding movement of at least a portion of the supporting surfaces.

Preferably, the apparatus comprises tensioning means.

Preferably, the tensioning means comprises one or more tensioning rollers around which the supporting belts are routed. Optionally, a driving means is provided to drive the supporting belts.

Preferably, the tensioning rollers also act as the driving means.

Preferably, the driving means is activated upon movement of the contact cleaning assembly.

Most preferably, the driving means is user controllable to select the distance through which a work-piece to be cleaned is conveyed relative to the framework.

Preferably, the contact cleaning assembly comprises a pair of opposed cleaning rollers which define a nip for receiving a work-piece to be cleaned.

Preferably, the contact cleaning assembly is pivotally mounted on the framework.

Preferably a support member is mounted on the contact cleaning assembly. More preferably, on tilting the contact cleaning assembly, the support member dislodges one of said rollers from an operating position to a maintenance position in which it can be accessed.

The contact cleaning assembly may be titled from a cleaning position to a maintenance position in which the cleaning rollers can be conveniently accessed.

Advantageously, driving means are provided on the framework to drive the contact cleaning assembly along the framework. Preferably, driving means for the contact cleaning assembly is adapted to drive the opposed cleaning rollers in the opposite direction to the contact cleaning assembly.

Most preferably, the driving means cooperates with a gear wheel on the cleaning rollers to drive the cleaning rollers at a speed synchronised to the speed of travel of the contact cleaning assembly.

Advantageously, the driving means is a toothed belt.

According to a second aspect of the present invention there is provided surface cleaning apparatus adapted to control the positioning of a work- piece to be cleaned, the apparatus comprising: a framework; a contact cleaning assembly positionable on the framework, the contact cleaning assembly comprising a cleaning roller and a co-operating adhesive roller wherein the respective rollers are mounted for relative movement between (i) a first position in which the cleaning roller abuts against the adhesive roller; and (ii) a second operating position in which the cleaning roller and adhesive roller are separated; and wherein a cam surface is provided on a bearing member projecting from the framework, said bearing member acting against a corresponding cam surface within the cleaning assembly to produce said relative movement.

Preferably the bearing member projects from the framework.

The cam surface within the cleaning assembly can be provided on an actuating means. In one embodiment the actuating means can be a bar. Alternatively the actuating means can be a cam follower. Vertical movement of the actuating means can pushe an adhesive roller from the first position to the second position.

Alternatively vertical movement of the actuating means lifts an adhesive roller from the first position to the second position.

Preferably one or more adhesive roller is biased into the first position. Most preferably the biasing means is a spring.

According to a further aspect of the present invention, there is provided a method of controlling the position of a work-piece to be cleaned relative to the framework of a surface cleaning apparatus, said method comprising the steps of: (i) providing a contact cleaning assembly adapted to receive a work-piece to be cleaned, the assembly being positioned between spaced first and second work-piece supporting surfaces;

(ii) positioning a work-piece to be cleaned on the first work- piece supporting surface;

(iii) moving the contact cleaning assembly towards a work- piece to be cleaned such that it is received therein; and (iv) continuing said movement of the contact cleaning assembly until the cleaned work-piece is positioned on the second work-piece supporting surface.

Optionally, the work-piece is maintained in a stationary position relative to the framework during the step of moving the contact cleaning assembly. Alternatively, the method includes the additional step of conveying the work-piece to be cleaned relative to the framework during the step of moving the contact cleaning assembly.

Preferably, the contact cleaning assembly includes a pair of opposed cleaning rollers which define a nip for receiving a work-piece to be cleaned and the method includes the additional step of driving the contact cleaning assembly in a first direction whilst simultaneously rotating the cleaning rollers of the assembly at a synchronised speed to that of the assembly, in the opposite direction.

Embodiments of the invention will now be described, by way of example only, with reference to the following drawings, in which:

Fig. 1 is a perspective view of surface cleaning apparatus showing a work-piece to be cleaned positioned on a first work-piece supporting surface;

Fig. 2 (not to scale) is a cross-sectional view of the surface cleaning apparatus of Fig. 1 ; Fig. 3 (not to scale) is a cross-sectional view of an alternative surface cleaning apparatus;

Figs. 4-6 (not to scale) are side views of an alternative embodiment of a contact cleaning assembly to that shown in Fig. 1 in an operation condition, tilting condition and maintenance condition respectively;

Figs. 7-9 are side views of a further embodiment of the present invention providing for separation of the adhesive rollers from the cleaning rollers at the ends of the framework, and Figs 10-12 are schematic side views of an alternative embodiment of the present invention providing for separation of the adhesive rollers from the cleaning rollers at the ends of the framework.

Fig. 1 shows surface cleaning apparatus comprising a rectangular framework 10 having a base and side walls, and a contact cleaning assembly 12 mounted therein for slidable movement between the opposite ends 10a and 10b of the framework 10. As described in more detail below, the contact cleaning assembly 12 comprises two sets of opposed cleaning rollers which define two nips through which a work-piece 14 to be cleaned may pass. The nip of the cleaning rollers is arranged such that it is aligned with the plane of the work-piece 14 to be cleaned.

The work-piece to be cleaned 14 is supported on a first work-piece supporting surface 16 of variable length. In the example shown in Fig. 1 , the supporting surface 16 is defined by a series of parallel belts 16a which are maintained in a tensioned state between the end 10a of the framework and a first supporting roller 12a which forms part of the contact cleaning assembly 12. The term 'belts' is to be understood to include any flexible or deformable material or structure which is capable of being routed around a series of rollers, for example ribbons, straps, bands, webs etc.

A second work-piece supporting surface 18 (not shown in Fig. 1 ) is also of variable length and is spaced from the first supporting surface 16 by the contact cleaning assembly 12. The second work-piece supporting surface 18 is also defined by a series of parallel belts 18a which are maintained in a tensioned state between the end 10b of the framework and a second supporting roller 12b of the contact cleaning assembly 12. In a first embodiment of the invention (as shown in Fig. 2), the distal ends of the parallel belts 16a, 18a which define the first and second work-piece supporting surfaces 16, 18 are each fixed to the respective opposite ends 10a, 10b of the framework 10. The respective supporting belts 16a, 18a are integrally formed from a continuous piece of material which is maintained in its tensioned state by a series of tensioning rollers 20a-d. As mentioned above, the contact cleaning assembly 12 comprises two sets of cleaning rollers 12a-d. The cleaning rollers 12a and 12b each contact an adhesive roller 13a, and the cleaning rollers 12c and 12d each contact an adhesive roller 13b. A nip 15 is defined between the respective sets of cleaning rollers 12a,b and 12c,d through which a work-piece 14 to be cleaned may pass.

In use, the contact cleaning assembly 12 is moved towards one end of the framework 10. In the example shown in Rg. 1 , the cleaning assembly 12 is moved into a pre-cleaning position adjacent to end 10b thus maximising the length of the first supporting surface 16 and minimising the length of the second supporting surface 18. A work-piece 14 to be cleaned can then be positioned on the first supporting surface 16.

The cleaning assembly 12 is then moved (either manually or by automated means) towards the opposite end 10a of the framework 10 such that the work-piece 14 passes through the nip 15 of the cleaning rollers 12a-d. As the cleaning rollers 12a-d rotate over the surface of the work-piece 14, any debris and/or contamination thereon is transferred to, and retained by, the respective adhesive rollers 13a and 13b in a manner which is known in the art. As the cleaning assembly 12 continues to move in the direction of end 10a of the framework 10 the work-piece 14 exits the nip 15 of the cleaning rollers 12a-d. As the cleaning assembly 12 is moved from the end 10b of the framework 10 towards end 10a, the supporting rollers 17a, 17b rotate along the underside of the supporting belts 16a, 18a causing a complementary increase in the length of supporting surface 18 and decrease the length of supporting surface 16. Once the cleaning assembly 12 is moved to a post-cleaning position at end 10a of the framework 10, the length of the first supporting surface 16 is minimised and the length of the second supporting surface 18 is maximised. The work-piece 14 is maintained in a stationary position relative to the framework 10 during the movement of the contact cleaning assembly 12.

Accordingly, it will be appreciated that the surface cleaning apparatus according to the first embodiment obviates the need for fixed length input and output supporting surfaces thus reducing the overall dimensions and footprint of the apparatus.

In a second embodiment of the invention (as shown in Fig. 3), the continuous piece of material takes the form of an endless loop which is maintained in its tensioned state by a series of inner tensioning rollers 20a-d and outer tensioning rollers 22a-d. When formed in an endless loop, the continuous piece of material is actively drivable by a driving means (not shown) in the direction indicated by the small arrows in Fig. 3.

In use, the apparatus of the second embodiment operates in a similar manner to that of the first embodiment. However, the apparatus of the second embodiment provides the additional optional feature of conveying the work-piece 14 relative to the framework 10 during the movement of the contact cleaning assembly 12. The conveying of the work-piece 14 relative to the framework 10 is achieved by driving the endless loop by a driving means (not shown). The tensioning rollers 20a-d and 22a-d may serve the dual function of driving the endless loop and maintaining it in a tensioned state. The tensioning rollers 20a-d and 22a-d are arranged such that the supporting surfaces 16, 18 both travel in a first direction which is opposite to the direction of travel of the cleaning assembly 12.

Accordingly, in an analogous example to that described above with reference to the first embodiment, the cleaning assembly 12 is moved into a pre-cleaning position adjacent to end 10b to allow a work-piece 14 to be cleaned to be positioned on the first supporting surface 16. The cleaning assembly 12 is then moved (either manually or by automated means) to the opposite end 10a of the framework 10 such that the work-piece 14 passes through the nip 15 of the cleaning rollers 12a-d with the supporting rollers 17a, 17b operating in an identical fashion as described previously.

However, as the cleaning assembly is moved from end 10a towards end 10b of the framework 10, the driving means drives the endless loop such that the supporting belts 16a, 18a move in the opposite direction (i.e. from end 10a towards end 10b). In doing so, the work-piece 14 is conveyed relative to the framework 10 towards end 10b during the movement of the cleaning assembly 12 towards end 10a.

Accordingly, it will be appreciated that the surface cleaning apparatus according to the second embodiment also obviates the need for fixed length input and output supporting surfaces thus reducing the overall dimensions and footprint of the apparatus. Moreover, the cleaning apparatus according to the second embodiment is particularly suitable for cleaning work-pieces 14 which are longer than the maximum length of the respective supporting surfaces 16, 18 and which therefore could not be completely cleaned by the apparatus of the first embodiment.

In a further embodiment of the present invention, the cleaning assembly may be pivotally mounted to the frame such that tilting of the cleaning assembly from the operation position shown in Fig. 4 to a maintenance position shown in Fig. 6 in which the lower adhesive roller 13b can be easily accessed.

In this embodiment like elements are numbered as in the previous embodiments. The cleaning assembly 12 has an upper body 12e within which the cleaning rollers 12a and 12c and the upper adhesive roller 13a are mounted. The upper body 12e is pivotally mounted upon the ends of the supporting roller 17b through a pair of side plates 24 which may be integrally provided on the upper body.

A substantially L-shaped support member 26 is provided on the side plates. The support member comprises a vertical leg which depends from the lower surface of the side plate and a horizontal leg extending from the free end of the vertical leg. A detent 28 is formed in the support member at the intersection of the vertical and horizontal legs. The lower adhesive roller 13b is mounted for rotation on a spindle 30 which is rotatably mounted within the cleaning assembly during operation. During operation of the cleaning assembly, the ends of the spindle are supported on the bottom of a slot 32 in a side member 12g of the lower body of the cleaning assembly.

A latching mechanism (not shown) is provided between the upper body 12e and the lower body 12f of the cleaning assembly. The movement of the cleaning assembly between an operating and a maintenance position will now be described. With the cleaning assembly stationary on the frame, the latching mechanism is released to free the upper body 12e for tifting with respect to the lower body 12f. The upper body is rotated around the support roller 17b. As the upper body rotates, the side plates 24 rotate thereby raising the horizontal leg of the support member 28 within the lower body 12f until it engages the spindle 30 of the lower adhesive roller 13b.

Further tilting of the upper body 12e causes the horizontal leg of the support member to continue rising until the spindle 30 of the lower adhesive roller 13b is raised within the slot 32 and engaged within the detent 28 of the support member. This position is shown in Fig. 5.

As the upper body 12e continues pivoting around the support roller 17b to the position shown in Fig. 6, lower adhesive roller 13b is raised clear of the lower body 12f of the cleaning assembly from where it can be easily accessed for repair or replacement.

Once the maintenance is completed, the lower adhesive roller 13b is mounted into the support member and the upper body of the cleaning assembly is rotated in the opposite direction around the support roller 17b to lower the adhesive roller 13b back into the lower body 12f . As the horizontal leg of the support member rotates to the operating position, the spindle of the adhesive roller 13b is released from the detent 28 and drops to the bottom of the slot 32.

Further rotation of the upper body towards the lower body continues until the upper body returns to the position shown in Fig 4 and the latching mechanism is operated to hold the upper body of the cleaning assembly in the operating condition.

This embodiment allows the user to access the lower adhesive roller for maintenance or repair without having to reach into the lower body of the cleaning assembly or having to disassemble the components thereof. This provides a significant improvement in the down time of the cleaning assembly during maintenance or repair procedures.

As a further enhancement, the upper adhesive roller 13a (not shown in

Figs 4-6) may be mounted within the upper body 12e on a sloping surface such that when the upper body is tilted to the maintenance position shown in Fig 6. The upper adhesive roller is drawn out of contact with the upper cleaning rollers 12a, 12c shown in Figs 1-3. This ensures that the surface of the upper rollers is not compromised by static contact with the upper adhesive roller during maintenance or repair.

In a further embodiment of the present invention, a cam separator 33 is provided at one or both ends of the framework 10. Figures 7-9 illustrate the tilting embodiment of the cleaning assembly in combination with a cam separator. However, it is envisaged that the cam separator can be used on other contact cleaning assemblies and may be retrofitted to existing apparatus. A projection 34 is mounted on one or either end of the framework. The projection extends substantially horizontally from the end into the framework. The distal end 35 of the projection, remote from the end of the framework has upper and lower cam surfaces 36,37 which in the embodiment shown are tapered surfaces sloping gradually from the sides 38 of the projection to a point at the distal end 35. An actuating bar 39 is mounted within the cleaning assembly, the bar may be mounted in bearings (not shown) to allow the bar to travel vertically within the cleaning head by a controlled amount. The bar extends to a position beneath the axle 40 of the upper adhesive roller. The lower end 41 of the actuating bar has a rounded surface 42 as will be explained further below.

A cam follower 43 is mounted within the cleaning head at a position below the lower end 42 of the actuating bar. The cam follower is connected either directly or indirectly to the axle 44 of the lower adhesive roller 13b. Tension means which in this embodiment are springs 45 are provided between the framework and the cam follower.

The upper surface of the cam follower has a tapered surface 46 which rises on either side to an apex 47 in the centre of the follower.

In operation, as the cleaning head approaches the end of the framework 10a, the projection 34 enters an aperture (not shown) in the side of the cleaning head and the upper tapered surface 36 of the distal end of the projection contacts the lower end 41 of the actuating bar. The lower tapered surface 37 of the distal end of the projection contacts the upper surface 46 of the cam follower.

As the cleaning head continues to travel towards the end of the framework, the lower end 41 of the actuating bar is raised by the tapered cam surface which in turn pushes the actuating bar upwards against the axle 40 of the upper adhesive roller 13a. The upper adhesive roller is lifted clear of the cleaning rollers 12a, 12c. At the same time, the lower tapered surface 37 of the projection rides over the sloping surface 46 of the cam follower and the follower is pushed downwards within the cleaning head against the bias of springs 45. As the cam follower travels downwards within the cleaning head, the lower adhesive roller 13b is pulled downwards out of contact with the lower cleaning rollers 12b, 12d.

Therefore, when the cleaning head is momentarily at rest at the end of the framework 10a before changing direction, the upper and lower adhesive rolls 13a, 13b are automatically lifted or lowered clear of the surface of the cleaning rollers 12a-d which increases the lifetime of the rollers and ensures that the surface of the cleaning rollers is not compromised by static contact with the upper adhesive rollers during use of the apparatus.

In an alternative embodiment shown in Figs 10-12, the cam follower is replaced by a lower actuating bar 39' similar to that provided to lift the upper adhesive roller 13a clear of contact with the cleaning roller 12a, 12c. In this embodiment, both upper and lower actuating bars 39, 39' have rounded ends which ride up the tapered upper and lower surfaces respectively of the distal end of the projection 34. The lower actuating bar 39' pushes the axle of the lower adhesive roller downwards against the spring force 45 out of contact with the lower cleaning rollers.

As the cleaning head moves away from the end 10a of the framework, the actuating bars ride back along the tapered upper and lower surface of the projection and the lower adhesive roller 13b is returned to the contact position under the spring bias, whilst the upper cleaning roller 13a is returned to the contact position under gravity. Modifications and improvements may be made without departing from the scope of the present invention. For example, the driving means may be automatically activated upon movement of the contact cleaning assembly from its pre-cleaning position. The driving means may be user controllable to select the distance through which a work-piece to be cleaned is conveyed relative to the framework. In particular, the distance through which a work-piece to be cleaned is conveyed relative to the framework may be automatically determined dependent upon the length of a work- piece to be cleaned.

As described above, automated driving means may be provided to drive the cleaning assembly from one end of the frame to another. In one embodiment, the automated driving means may be provided by a closed loop such as a toothed belt which is mounted internally of the frame. The toothed belt passes through the cleaning assembly such that driving the belt provides for movement of the assembly. Additionally, the toothed belt may be adapted to drive a gear on the opposed cleaning rollers of the cleaning assembly such that upon movement of the cleaning assembly from one end of the frame to the other, the cleaning rollers are rotated at a synchronised speed with respect to the assembly but in the opposite direction thereof. This ensures that there is no movement of the workpiece relative to the support surfaces during the cleaning operation.

Claims

1. A surface cleaning apparatus adapted to control the positioning of a work-piece to be cleaned, the apparatus comprising: a framework; spaced first and second work-piece supporting surfaces; a contact cleaning assembly positionable between said spaced supporting surfaces, the assembly adapted to receive a work-piece to be cleaned and being mountable on said framework and movable thereon; wherein the contact cleaning assembly is provided with first and second supporting members each adapted to support a portion of the respective supporting surfaces; and wherein movement of the contact cleaning assembly on the framework causes corresponding movements of the first and second supporting members to cause a complementary increase and decrease in the lengths of the respective work-piece supporting surfaces.

2. The apparatus of claim 1 , wherein the first and second work-piece supporting surfaces are provided on supporting belts adapted such that at least a portion of each belt is maintained in a stationary position relative to the framework during the movement of the contact cleaning assembly.

3. The apparatus of claim 1 , wherein the first and second work-piece supporting surfaces are provided on supporting belts adapted such that each belt is conveyed in a direction opposite to that of the contact cleaning assembly during the movement of the contact cleaning assembly.

4. The apparatus of any of claims 1 -3, wherein the supporting belts are each defined by a series of spaced parallel belts.

5. The apparatus of any of claims 1 -3, wherein the supporting belts are each comprised of a unitary web of material.

6. The apparatus of claims 4 or 5, wherein the respective supporting belts are connectable together.

7 The apparatus of claims 4 or 5, wherein the respective supporting belts are comprised of a continuous piece of material.

8. The apparatus of claim 7, wherein the continuous piece of material comprises an endless loop.

9. The apparatus of any of claims 2-8, wherein the first and second supporting members are rollers, each adapted to support the underside of the respective supporting belts.

10. The apparatus according to any of the preceding claims, wherein movement of the contact cleaning assembly is adapted to cause a corresponding movement of at least a portion of the supporting surfaces.

11. The apparatus according to any of the preceding claims, wherein the apparatus comprises tensioning means.

12. The apparatus according to claim 11 when dependent upon claim 2 or 3, wherein the tensioning means comprises one or more tensioning rollers around which the supporting belts are routed.

13. The apparatus according to any of claims 2-12, wherein a driving means is provided to drive the supporting belts.

14. The apparatus of claim 11 or 12, wherein the tensioning rollers also act as driving means.

15. The apparatus of claim 13 or 14, wherein the driving means is activated upon movement of the contact cleaning assembly.

16. The apparatus of any of claims 13-15, wherein the driving means is user controllable to select the distance through which a work-piece to be cleaned is conveyed relative to the framework.

17. The apparatus according to any of the preceding claims, wherein the contact cleaning assembly comprises a pair of opposed cleaning rollers which define a nip for receiving a work-piece to be cleaned.

18. The apparatus according to any of the preceding claims, wherein the contact cleaning assembly is pivotally mounted on the framework.

19. The apparatus according to claim 18 when dependent upon claim 17, wherein the contact cleaning assembly may be titled from a cleaning position to a maintenance position in which the cleaning rollers can be conveniently accessed.

20. The apparatus of claim 18 or 19 wherein a support member is mounted on the contact cleaning assembly.

21. The apparatus of claim 20, wherein on tilting the contact cleaning assembly, the support member dislodges one of said rollers from an operating position to a maintenance position in which it can be accessed.

22. The apparatus according to any of the preceding claims, wherein driving means are provided on the framework to drive the contact cleaning assembly along the framework.

23. The apparatus according to claim 22, wherein the driving means for the contact cleaning assembly is adapted to drive the opposed cleaning rollers in the opposite direction to the contact cleaning assembly.

24. The apparatus according to claim 23, wherein the driving means cooperates with a gear wheel on the cleaning rollers to drive the cleaning rollers at a speed synchronised to the speed of travel of the contact cleaning assembly.

25. The apparatus according to any of claims 22-24, wherein the driving means is a toothed belt.

26. A surface cleaning apparatus, the apparatus comprising: a framework; a contact cleaning assembly positionable on the framework, the contact cleaning assembly comprising a cleaning roller and a co-operating adhesive roller wherein the respective rollers are mounted for relative movement between (i) a first position in which the cleaning roller abuts against the adhesive roller; and (ii) a second operating position in which the cleaning roller and adhesive roller are separated; and wherein a cam surface is provided on a bearing member of the apparatus, said bearing member acting against a corresponding cam surface within the cleaning assembly to produce said relative movement.

27. The apparatus of claim 26, wherein the bearing member projects from the framework.

28. The apparatus of claim 26 or 27, wherein the cam surface within the cleaning assembly is provided on an actuating means.

29. The apparatus of claim 28, wherein the actuating means is a bar.

30. The apparatus of claim 27, wherein the actuating means is a cam follower.

31. The apparatus of any of claims 28-30, wherein vertical movement of the actuating means pushes an adhesive roller from the first position to the second position.

32. The apparatus of any of claims 28-30, wherein vertical movement of the actuating means lifts an adhesive roller from the first position to the second position.

33. The apparatus of any of claims 26-32, wherein one or more adhesive roller is biased into the first position.

34. The apparatus of claim 33, wherein the biasing means is a spring.

35. A method of controlling the position of a work-piece to be cleaned relative to the framework of a surface cleaning apparatus, said method comprising the steps of:

(i) providing a contact cleaning assembly adapted to receive a work-piece to be cleaned, the assembly being positioned between spaced first and second work-piece supporting surfaces; (H) positioning a work-piece to be cleaned on the first work- piece supporting surface;

36. The method according to claim 35, wherein, the work-piece is maintained in a stationary position relative to the framework during the step of moving the contact cleaning assembly.

37. The method according to claim 35, the method includes the additional step of conveying the work-piece to be cleaned relative to the framework during the step of moving the contact cleaning assembly.

38. The method according to any of claims 35-37, wherein the contact cleaning assembly includes a pair of opposed cleaning rollers which define a nip for receiving a work-piece to be cleaned and the method includes the additional step of driving the contact cleaning assembly in a first direction whilst simultaneously rotating the cleaning rollers of the assembly at a synchronised speed to that of the assembly, in the opposite direction.