GB2566763A - Perforating tool - Google Patents

Abstract

The invention relates to a tool 10 used to perforate wallpaper to enable a solvent, which may be water or steam, to reach an adhesive layer on the paper's rear face and so soften or dissolve it, facilitating removal of the paper from a wall. The tool has a housing 12 with an opening 18 and a registration surface 16 for contacting the wallpaper. A rotor 14 is mounted within the housing for rotation about an axis which is fixed with respect to the housing. The axis of the rotor is substantially parallel to the wallpaper when the registration surface is in contact with it. An electric motor 28 for driving the rotor is disposed coaxially with the rotor. There are projections formed upon the rotor which extend outwardly through the opening in the housing to engage the wallpaper. The motor may be disposed wholly or partly inside the rotor. The housing may be provided with a port (32, fig. 1) for connection to an air extraction device such as a domestic vacuum cleaner.

Description

PERFORATING TOOL

The invention relates to a tool used to perforate wallpaper. The tool may be used to enable a solvent, which may be water or steam, to reach an adhesive layer on the paper's rear face and so soften or dissolve it, facilitating removal of the paper from a wall.

When re-decorating a room it is often necessary to remove existing paper from the walls before applying a fresh covering such as paint or a new wallpaper. The removal process is laborious, typically involving scraping the wallpaper with a hand tool. It can be facilitated by softening the adhesive layer on the wall-facing side of the paper using water, steam or some other suitable solvent, but to enable the solvent to reach the adhesive the paper typically needs to be perforated in some manner. This applies especially but not exclusively to water-impermeable wallpapers.

The prior art contains a range of tools for perforating wallpaper.

Some such tools use manual power alone. An example which is widely commercially available has a spiked roller rotatably mounted to an elongate handle akin to a broom handle, the roller's axis of rotation being perpendicular to the handle. The roller is run across the wallpaper with firm pressure so that the spikes penetrate the paper.

The effectiveness of this device is highly variable because the size and depth of the perforations depends on the force applied by the user. The perforations can be too small and so expose insufficient backing layer, or not deep enough to penetrate multiple layers of wallpaper, both of which will result in the user having to perforate, soak and scrape the same area multiple times. Perforations can also be too deep and damage the underlying plaster.

The same drawbacks apply to the scoring tool disclosed in US3738001, which has a curved blade with a castellated cutting edge fixed to an elongate handle. The blade in this case does not rotate but is simply drawn across the paper surface to scrape it, involving arduous manual effort.

GB2053767 and US4274202 both disclose handheld perforating devices having a pair of spiked rollers whose axes are inclined one to the other at an obtuse included angle, the effect being to cause the spikes to move laterally while in engagement with the wallpaper, tearing it somewhat to provide elongate slits rather than point perforations. The manual effort needed to roll the device across the paper is however increased by this tearing action, and again the depth of the perforations is dependent on the pressure applied by the user, and is therefore undesirably variable.

The device of US5163966, has a pair of toothed wheels for scoring the paper, their axes again being inclined one to the other to provide a tearing effect. The wallpaper removal tool of WO2008/124398 has multiple pairs of toothed wheels inclined one to the other. Here again, the user's manual effort drives the wheels and their tearing action, requiring significant manual exertion.

Use of manually driven perforators can prove to be laborious and slow. Laborious because of the need to apply force and the resistance of the wallpaper, especially while reaching overhead. Slow because of the tiring nature of the work, and because of the need to reposition ladders or platforms used to reach the top of walls and ceilings.

Wallpaper perforating devices using an electric motor to drive a rotary mechanism have been proposed in the past. Examples are to be found in EP1688270, SE463019, US370880 and US2006/174740. A feature common to the powered devices disclosed in these documents is that the powered drive turns some form of carrier about an axis which is perpendicular to the plane of the wall/wallpaper in use. In the device of US3708880 four circular but fixed (i.e. non-rotatable) blades are carried on a cutter-supporting body mounted to the chuck of an electric drill. The other three documents all describe arrangements having a three-spoked carrier turned about the aforementioned axis perpendicular to the plane of the paper by an electric drive, each arm having freely rotatable wheels or drums upon it to provide the perforating effect. These are somewhat complex devices mechanically and potentially subject to clogging by the material that they cut and score.

A simpler configuration is represented in GB0910399, in which a scraping and polishing apparatus employs a generally cylindrical rotary brush which rotates about an axis parallel to the plane of the wall in use. The brush is driven by means of an electric motor through a reduction gear train, the motor being offset from the brush. US2319023 concerns a device for preparing walls for redecoration which likewise has a cylindrical part (a grinding roller in this instance) that rotates about an axis parallel to the plane of the wall, being driven through a belt drive in this instance.

The use of an offset motor with a geared or belt drive in these devices increases their complexity and bulk. The drive mechanism is also potentially problematic because the device by its nature creates a quantity of cut or shredded material which may enter and clog the drive mechanism.

The present invention is intended to provide an improved device for perforating or removing a wall covering.

The words paper and wallpaper are used interchangeably herein. Both refer to any form of thin wall covering in sheet form.

In accordance with the present invention, there is a tool for perforating or removing a wall covering, comprising a housing having an opening and having a registration surface for contacting a surface of the wallcovering, a rotor mounted within the housing for rotation about an axis which is defined with respect to the housing and is substantially parallel to the said surface of the wallcovering when the registration surface is in contact with it, projections formed upon the rotor which extend outwardly through the opening in the housing, to engage the wallcovering, and an electric motor arranged coaxially with the rotor and coupled to it, to drive the rotor rotationally.

A rotor turning about an axis parallel to the plane of the wall/paper provides effective scoring without undue constructional complexity. Its powered drive minimises manual effort. The registration surface defines a maximum depth of cut and can serve to ensure consistency in the depth of penetration of the projections into the paper. The axis of rotation of the rotor is static with respect to the housing while the tool is in use, but its separation from the registration surface may be adjustable to enable the depth of penetration of the spikes to be adjusted. This may be achieved by small movement of the member forming the registration surface, or of the axis of rotation of the rotor. A screw mechanism may be provided for making such adjustment. This may comprise a worm and wheel arrangement.

Coaxial mounting of the rotor and the motor provide a particularly compact and convenient arrangement. The motor can provide the rotary bearing needed at one end of the rotor. The motor may in some embodiments be partially or wholly contained inside the rotor, minimising the axial extent of the whole device. Without an offset drive, there need be no exposed components whose operation might be impaired by fouling with waste material.

Specific embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which:Figure 1 is a side view of a first wallpaper perforating tool embodying the present invention;

Figure 2 is a further side view of the tool represented in Figure 1, a side wall and a base wall being omitted to reveal internal detail;

Figure 3 is a side view of a second wallpaper perforating tool embodying the present invention, a side wall being omitted to reveal internal detail;

Figure 4 is a scrap view of a motor and rotor assembly according to a further embodiment of the present invention; and

Figure 5 is a further scrap view of a different motor and rotor assembly according to an embodiment of the present invention.

The wallpaper perforating tool 10 depicted in Figures 1 and 2 comprises a housing 12 containing a rotor 14. The housing 12 is a hollow structure which may for example be of injection moulded plastics. It has a base wall providing a registration surface 16, which in the present embodiment is planar and flat. An opening 18 is formed in the base wall, through the registration surface 16. Side walls 20 upstanding from the base wall define an internal space for the working parts of the tool, which are thus guarded to minimise the risk of injury e.g. by accidental insertion of a fingertip.

The rotor 14 is mounted inside the housing 12. The rotor 14 comprises a cylindrical rotor body whose outer surface is provided with a plurality of projections 22 for perforating the wallpaper. In the present embodiment these projections take the form of upstanding conical spikes with sharp tips, although they may take a range of different shapes in other embodiments. The rotor 14 lies adjacent the opening 18 in the base wall so that its cylindrical body 24 is wholly within the housing 12 but the projections 22 extend outwardly of the plane defined by the registration surface 16, to engage the wallpaper itself. The distance that the projections extend beyond that plane is thus the effective limit of the depth to which the projections 22 can penetrate the wallpaper on a flat wall.

The rotor 14 is driven by an electric motor 26. The motor 26 is coaxial with the rotor 14. In the present embodiment the motor drives the rotor 14 directly. The motor 26 is in the present embodiment the motor 26 is largely contained within the rotor 14, which is tubular. A rotor shaft 28 in this example extends coaxially from the rotor 14 to mount the motor 26 to the housing 12 and react the motor's torque to it.

A range of different arrangements is possible for coaxial mounting of the rotor 14 and the motor 26. Figure 4 for example shows an arrangement with an outrunner type motor 26a whose working parts are contained in the rotor 14a and whose shaft 28a is received by a fixed mounting 37. An outer shell 30 of the motor 26a revolves about a fixed inner part including the shaft 28a and the motor's windings. The outer shell 30 carries and turns the rotor 14a.

The arrangement in Figure 5 uses a conventional motor 26b mounted to the housing 12 outboard of the rotor 14b, the motor's shaft 28b being coupled coaxially to the rotor 14b to mount and turn it. The axial length of the assembly could be reduced by placing the fixed motor inside a tubular or partly tubular version of the rotor 14b.

In each of the illustrated examples the motor 14, 14a, 14b provides a rotary mounting for one end of the rotor 14, 14a, 14b. The other end of the rotor has a rotary bearing (not seen) through which it is mounted to the housing 12. This may for example be a plain bearing or a ball bearing.

The motor 26 may be driven from an onboard battery pack 29 (see Figure 2), which may be rechargeable through a connector 31. Alternatively the battery pack may be dispensed with and the motor 26 driven through a cable led to a mains supply.

Uncontrolled release of material cut from the wall by the rotor is undesirable, not only because of the mess created but for safety reasons. Lead-based paint is still commonly found in UK homes and arsenic-based wallpaper was in common use in the nineteenth century and can be encountered during renovations.

The housing 12 provides an air port 32 which serves two functions in the present embodiment. As well as providing for flow of air to the housing 12 for waste extraction purposes it serves to engage with a tubular conduit 34 used as a handle for the tool 10. For this purpose the air port 20 is inclined with respect to the registration surface 22, making it easy for a user holding the conduit 34 to present the tool to the wall with registration surface 22 flat against it.

Typically the tool 10 will be used with a domestic cylinder type vacuum cleaner serving to extract and collect waste material, in which case the conduit 34 will be the tube that forms the vacuum cleaner's handle. The tool 10 may be supplied with one or more adapters to be interposed between the conduit 34 and the air port 20, to enable the tool to receive and couple to handles from multiple different vacuum cleaner types and/or manufacturers.

In other embodiments the functions of air port 32 and handle may be served by separate components.

The housing 12 is configured such that air drawn through it by the air extraction device enters it through the opening 24 (and in the present embodiment this is the only route for entry of air to the housing) and flows past the rotor 16 to entrain shreds of cut wallpaper and other material released by the perforating process before exiting the housing 12 through the air port 20.

In use, the tool 10 is to be run across the surface of the wallpaper to be scored. The length of the conduit/handle 34 makes it possible to reach a large area of wall whilst standing still, and to reach high areas without need of a stepladder. The registration surface 22 is maintained adjacent to or in contact with the wallpaper surface, and roughly parallel to it, by the user. The projections 28 of the roller 16 engage the wallpaper through the opening 24 and as they turn produce the required perforations, after which a solvent - be it steam, water or some other substance - is applied to loosen the paper preparatory to its removal.

In the above described embodiments the registration surface 16 which defines the maximum depth of cut lies in a flat plane. Figure 3 illustrates another option in this respect. The wallpaper perforating tool 100 of this drawing is a variant of that depicted in Figure 1, differing from it in that the registration surfaces 116 formed by the lower peripheries of the housing walls 125 lie on a locus which is circular, when viewed along the direction of the axis of the rotor 114. The centre of this circular locus coincides with the rotor's axis. The effect is that some variation of the angle between the tool and the wall can be accommodated without causing the rotor's spikes to disengage from the wallpaper, and without changing the maximum depth of cut.

The aforegoing embodiments are presented by way of example and not limitation. Numerous further variations are possible without departing from the scope of the invention as set out in the appended claims. For example whereas the illustrated embodiment is a tool for perforating wallpaper, other versions may be used for actual removal of a wallcovering, which may be wallpaper or may be a more substantial covering such as pebbledashing.

Claims (13)

1. A tool for perforating or removing a wall covering, comprising a housing having an opening and having a registration surface for contacting a surface of the wallcovering, a rotor mounted within the housing for rotation about an axis which is defined with respect to the housing and is substantially parallel to the said surface of the wallcovering when the registration surface is in contact with it, projections formed upon the rotor which extend outwardly through the opening in the housing, to engage the wallcovering, and an electric motor arranged coaxially with the rotor and coupled to it, to drive the rotor rotationally.

2. A tool as claimed in claim 1 in which the electric motor is disposed wholly or partly inside the rotor.

3. A tool as claimed in claim 1 or claim 2 in which the rotor is rotatably mounted at one end through a rotary bearing to the housing, and at the other end through the motor to the housing.

4. A tool as claimed in any preceding claim in which the motor has a radially inner portion carrying windings and a radially outer portion which is rotatable about the radially inner portion, the radially inner portion being mounted to the housing and the radially outer portion being coupled to the rotor to drive it.

5. A tool as claimed in claim 4 in which the motor's radially outer portion is received in the rotor.

6. A tool as claimed in any preceding claim in the housing is provided with a port for connection to an air extraction device.

7. A tool as claimed in claim 6 in which the air port is configured to connect to a domestic vacuum cleaner.

8. A tool as claimed in claim 6 or claim 7 in which the form of the housing is such as to cause waste material released by the perforation process to be entrained in airflow to the extraction device.

9. A tool as claimed in any of claims 6 to 8 in which the air port is coupled to an elongate conduit for connection to the air extraction device, the configuration being such that the elongate conduit is able to serve as a handle through which the tool is held in use.

10. A tool as claimed in any preceding claim in which the registration surface lies a flat plane.

11. A tool as claimed in any of claims 1 to 9 in which the registration surface lies on a circular locus whose centre coincides with the rotor's axis of rotation.

12. A tool as claimed in any preceding claim in which the rotor comprises a cylindrical body carrying the said projections.

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13. A tool as claimed in any preceding claim in which the projections have a conical shape.