GB2590684A

GB2590684A - Pole sander

Info

Publication number: GB2590684A
Application number: GB1919260.8A
Authority: GB
Inventors: schramm Benjamin; Droste Manfred
Original assignee: Black and Decker Inc
Current assignee: Black and Decker Inc
Priority date: 2019-12-23
Filing date: 2019-12-23
Publication date: 2021-07-07
Also published as: GB201919260D0

Abstract

A handheld pole sander comprising an electric motor. A sanding head pivotally attached to an elongate body (102, figure 2), comprises a hood 112 having a peripheral wall (160, figure 6A) on the underside and around the edge of a plate (156). A brush ring 132 is mounted inside the peripheral wall, adjacent the plate edge. The brush ring is attached to the plate via at least one leaf spring 186 or at least one wave spring, preferably formed from sheet metal and resiliently deformable in a direction perpendicular to the plane of the sheet. The brush ring may comprise a series of bristles 182 extending from the bottom side of a circular ring 180. Six leaf springs may be attached to a top side of the circular ring and extend through six apertures (166, figure 8) for attaching to a top side of the plate.

Description

POLE SANDER

The present invention relates to a pole sander.

Pole sanders typically comprise a telescopic pole with a sanding head pivotally mounted on one end. The sanding head comprises a hood which surrounds a platen which is mounted on an output spindle which projects from the hood. Sand paper can be attached to the platen for sanding a work surface. Alternatively, a polishing pad can be attached to polish a work surface. The output spindle and hence the platen, is rotated by an electric motor. The electric motor can be mounted on the sanding head. Alternatively, the motor can be mounted on the end of the telescopic pole remote from the sanding head. A vacuum cleaner can be attached to the sanding head, typically via a nozzle which connects to a pipe which extends through the telescopic pole, to remove dust generated by the sanding action of the rotating platen from under the hood.

Examples of pole sanders are disclosed in EP0727281, EP2033738, 0E102014103019, W02014/086873, EP3083139 and DE102014112355.

Accordingly, there is provided a handheld pole sander in accordance with claim 1.

Figure 1 shows a top view of the pole sander: Figure 2 shows a side view of the pole sander; Figure 3 shows a vertical cross-sectional view of the pole sander; Figure 4 shows a perspective view of the sanding head; Figure 5 shows an underside view of the sanding head with the platen removed; Figure 6A shows a vertical cross-sectional view of the edge of the sanding head; Figure 6B is the same as Figure 6A with the addition of hatching to show cross sectional area of gap between edge of the platen and the inner wall; Figure 7 shows a perspective view of the brush ring; Figure 8 shows a view of part of the top side of the plate with the leaf spring of the brush ring 132 passing through an aperture from below the plate to attach to the top side of the plate; Figure 9 shows a schematic diagram showing how the two poles of the elongate body are telescopically connected to each other; Figure 10 shows the seals which connect between the two poles of the elongate body; Figure 11A shows the seal for the first pole 196 being attached to the first pole 196; Figure 1113 shows a vertical cross section of the seal for the first pole 196 being attached to the first pole 196; Figure 11C shows the seal for the first pole 196 mounted on the first pole 196; Figure 12 shows the seals adjacent the ends of the aluminium tubes of the poles; Figure 13 shows a perspective cross section showing how the aluminium tubes and seals of the two poles of the elongate body are telescopically connected to each other; Figure 14 shows a perspective cross section showing how the aluminium tubes and seals of the two poles of the elongate body are telescopically connected to each other; Figure 15 shows a top view of the sanding head; Figure 16 shows a vertical cross section of the sanding head and lower end of the first pole 196; Figure 17 shows the underside view of the sanding head including the platen; Figure 18 shows the platen; Figure 19 shows the rear housing with one of the clam shells removed; Figure 20 shows a vertical cross section of the rear housing; Figure 21 shows a top perspective view of the sanding head; Figure 22 shows the extension tube inside the handle section of the rear housing with the vacuum nozzle detached; Figure 23 shows the extension tube inside of the handle section of the rear housing with the vacuum nozzle attached; Figure 24 shows the rear end of the extension tube with the vacuum nozzle detached; Figure 25 shows the rear end of the extension tube with the vacuum nozzle attached; Figure 26A and Figure 268 show a first angle of the tubular passageway of the hood; and Figure 27A and Figure 278 shows a second angle of the tubular passageway.

Referring to Figures 1 to 3, the pole sander comprises a sanding head 100 pivotally attached to one end of an elongate body 102 and a rear housing 104 attached to the other end.

The elongate body 102 is telescopic and is formed from two poles 196, 198, one of which slides in an out of the other as described in more detail below.

The sanding head 100 connects to the end of the elongate body 102 via a pivot mechanism 110 which is described in more detail below. The sanding head 100 comprises a hood 112 on top of which is mounted an electric motor 114. The motor 114 is a DC brushless motor 114. The motor 114 is enclosed by a motor housing 120 which is cup shaped and surrounds the top and sides of the motor 114. The motor housing 120 attaches to the top of a gear housing 122 which encloses a planetary gear set 124. The gear housing 122 mounts on top of the hood 112. The motor 114 is drivingly connected via the planetary gear set 124 to an output spindle 118 having a longitudinal axis 126 about which it rotates and which is located below the hood 112. Attached to the end of output spindle 118 is a circular platen 116 which extends radially outwards from the output spindle 118. When the motor 114 is activated, the motor 114 rotationally drives the output spindle 118 and hence the platen 116 about a drive axis 126.

A flexible dust extraction pipe 128 attaches to the top of the hood 112 on one side of the motor 114. An aperture 130 is formed through the hood 112. The end of the flexible pipe 128 surrounds the aperture 130. As such air can be drawn from beneath hood 112 through the aperture 130 and into the flexible pipe 128. This enables dust and debris generated during the operation of the pole sander to be removed from under the hood 112 by applying a suction force to the flexible pipe 128. The operation of the dust extraction of the pole sander is described in more detail below.

A brush ring 132 attaches to the edge of the hood 112. The brush ring 132 is described in more detail below.

The rear housing 104 is formed two plastic clam shells 134 which clamp to the end of the elongate body 102. The rear housing 104 comprises a forward mount section 136 and rear handle section 138. A battery mount 140 is formed on the lower surface of the mount section of the rear housing 104. A battery pack 142 can be slid in a forward direction (Arrow M in Figure 19) onto the battery mount 140 to attach it to the rear housing 104 and in a rearward direction to detach it from the battery mount 140. The design of the battery mount 140 and battery 142 are known in art and therefore will not be described in any more detail.

Control electronics 144 for the motor 114 are mounted inside of forward mount 136 section of the rear housing 104. The control electronics 144 are connected to the motor 114 via an electric cable 146 which passes through a second passageway 148 of the elongate body 102 through the length of the elongate body 102. The control electronics 144 control the operation of the brushless motor 114.

A lock on/lock off switch 150 is mounted on the top of rear housing 104 where the rear handle section 138 connects to the forward mount section 136. An operator can use the lock on/lock off switch 150 to activate the motor 114.

S

An operator can support the pole sander by grasping the rear handle section138 of the rear housing 104 in one hand and the elongate body 102 in the other. The operator can switch the pole sander on or off using the thumb of the hand grasping the rear handle section 138.

A vacuum connection nozzle 152 is mounted on the rear of the rear housing 104 which connects to a first passageway 154 which extends through the length of the elongate body 102. The other end of the second passage 154 connects to the flexible pipe 128. A vacuum cleaner (not shown) can be connected to the nozzle 152 and draw air from under the hood 112, through the flexible pipe 128, through the first passage 154 in the elongate body 102, through the nozzle 152 and into a vacuum cleaner.

The hood 112 will now be described with reference to Figures 4 to 6.

The hood 112 comprises a circular plate 156 which extends radially from a central Circular hole 158 through which the output spindle 118 projects. Formed on the underside of the plate 156 around the edge is a peripheral wall 160 which projects perpendicularly to the plane of the circular plate 156. An inner circular inner wall 162 is formed on the underside of the plate 156 in close proximity to and concentrically with the peripheral wall 160. The inner wall 162 has the same height as the peripheral wall 160 and extends in the same direction that is parallel to the peripheral wall 160. A circular trough 164 is formed between the two walls 160, 162.

Six rectangular apertures 166 are formed through the base of the trough 164. The apertures 166 are located equidistantly around the centre of the plate 156 in a symmetrical fashion. A chamber 166 is formed between the inner wall 162 and the underside of the plate 156.

Formed through the plate 156 between the inner wall 162 and the central hole is an arc shaped aperture 130 which allows air and debris to pass through the plate 156. The aperture 130 has three edges, a first straight edge 170 which extends tangentially to the longitudinal axis 126 of the output spindle 118, a second edge 172 of equal length which extends from the end of the first edge 170, perpendicularly to the first edge 170, in a direction away from the longitudinal axis 126 of the output spindle 118, and a third curved edge 174 extending between the ends of the first and second edges 170, 172. The circular plate 156 has a radius R. The whole of the arc shaped aperture 130 is located at a distance of less than half of the radius from longitudinal axis 126 of the output spindle 118 or the centre of the plate 156 (<R/2).

Integrally formed on the top side of the plate 156 is a curved wall 178 which forms a tubular passageway 176 from the arc shaped aperture 130 to an opening where the flexible pipe 128 is attached. Where the tubular passageway 176 connects to the arc shaped aperture 130, it is shaped to engage with the arc shaped aperture 130 at certain angles to maximise the air flow efficiency.

Referring to Figures 26A and 26B, the first angle of the exit of the tubular passageway 176 is located in a vertical plane 300 which passes through axis of rotation 126 of the output spindle 118 across the end of the tubular passage 176 adjacent the arc shaped aperture 130. The angle 302 in this plane 300 between the axis of rotation 126 of the output spindle 128 and the direction of the tubular passageway 176 is less than 90 degrees (perpendicular) but greater than 0 degrees (parallel) and is ideally between 20 degrees and 60 degrees.

Referring to Figures 27A and 27B, the second angle of the exit of the tubular passageway 176 is located in a vertical plane 304 which extends tangentially to the axis of rotation 126 of the output spindle 128, the part of the plane 304 which passes through the exit of the tubular passageway 176 being the closest part to the axis of rotation 126 of the output spindle 118. The angle 308 in this plane 304 between the plane of the circular plate 156 of the hood 112 and the direction of the tubular passage 176 in the turning direction 306 of the platen 116 is less than 90 degrees and is ideally between 20 degrees and 60 degrees.

The hood 112 is formed in a one-piece construction from plastic.

The brush ring 132 will now be described with reference to 6 to 8.

The brush ring 132 comprises a plastic circular ring 180 which is sized so that it is capable of locating inside of the trough 164. Extending perpendicularly from the bottom side of the ring 180 are a series of bristles 182. Attached to the opposite top side of the brush ring 132 are the ends 184 of six leaf springs 186. The leaf springs 186 are formed from sheet metal and are resiliently deformable in a direction perpendicular to the plane of the sheet. The leaf springs 186 comprises a central section 188 located between two end sections 184, 190. The end sections 184, 190 extend in a direction parallel to the top surface of the ring 180. The central section 188 of the leaf springs 186 extends upwardly at a slight angle to the plane of the circular ring 180. Each central section 188 of each leaf spring 186 extends through the rectangular aperture 166 in the trough 164 and attaches to the top side 194 of the plate 156 as shown in Figure 8. The leaf springs 186 bias the ring 180 to a position where it is located at a distance from the base of the trough 164 as shown in Figure 6. In this position, the bristles 182 project below the hood 112. When the sanding head 100 is placed against a work surface, the bristles 182 engage with the work surface. When the sanding head 100 is pushed against the work surface, the brush ring 132 is pushed into the trough 164 against the biasing force of the leaf springs 186. The leaf springs 186 ensure that the bristles 182 are biased into engagement with the work surface, When the sanding head 100 is removed from the surface, the brush ring 132 returns to its original position due to the resilient nature of the leaf springs 186.

A plastic cover 195 is located over the topside of the hood 112 enclosing the ends 190 of the leaf springs 186 attached to the top side 194.

It will be appreciated that a wave spring could be used instead of the leaf springs to attach the brush ring 132 to the plate 156. The wave spring could be is a nested wave spring, a crest to crest wave spring, a single turn wave spring, an interlaced wave spring or a combination of such wave springs. The wave spring would locate within the trough 164 between the brush ring and the base of the trough 164. Part of the wave spring could extend through the a pertures166 in order for that part to attach to the top side 194 of the plate 156.

The telescopic elongate body 102 will now be described with reference to Figures 1 to 3 and 9 to 14.

The pole sander has an elongate body 102 comprising a first pole 196 which is capable of sliding in and out of a second pole 198 in a telescopic manner to enable the length of the pole sander to be adjusted. A locking mechanism 200 is used to lock the first pole 196 to the second pole 198 when the two poles 196, 198 have been telescoped to a preferred length.

Inside both of the poles 196, 198 are two passageways 148, 154 which run the length of the both poles 196, 198. The first larger passageway 154 is used to transport air (due to suction) and entrained dust and debris, generated during the use of the pole sander, through the poles 196, 198 from the working end to a vacuum nozzle 152 at the opposite end, the nozzle 152 being connected to a vacuum cleaner. The second smaller passageway 148 is used as a conduit for electric cable 146 which provide power and control signals from a control electronics 144 for the electric motor 114 mounted in the sanding head 100.

The first pole 196 comprises a single aluminium tube with an internal wall 202 located inside of the tube, which runs the length of the tube to form the two passageways 148, 154 which run the length of the first pole 196. The first larger passageway 154 forms part of the first passageway which is used to transport air. The second smaller passageway 148 forms part of the passageway which is used as a conduit for the electric cable 146. A first seal 204 attaches to the end of the first pole 196 which is inserted into the second pole 198. The shape of the seal 204 corresponds to that of the end of the aluminium tube and internal wall 202. The first seal 204 provides a seal between the first pole 196 and the second pole 198. It also acts as a slide bearing.

The second pole 198 comprises two aluminium tubes 206, 208. The second aluminium tube 208 locates inside of the first aluminium tube 206 and runs the full length of the first tube 206, their longitudinal axes being parallel to each other. The second aluminium tube 208 forms part of the first passageway which is used to transport air and dust or debris. The first aluminium tube 206 forms part of the passageway 154 which is used as a conduit. A second seal 210 is attached to the end of the first aluminium tube 206 into which the first pole 196 is inserted. The shape of the second seal 210 corresponds to that of the end of the aluminium tube 206. A third seal 212 is attached to the end of the second aluminium tube 208 which is inserted into the second passage 148 way of the first pole 196. The shape of the third seal 212 corresponds to that of the end of the second aluminium tube 208. The seals 210,212 provides a seal between the first pole 196 and the second pole 198. They also act as slide bearings. The two tubes 206, 208 are connected to each other at their ends remote from the seals 210,212 so that relative movement between the two tubes 206, 208 is prevented.

The poles 196, 198 are assembled as following. The end with the third seal 212 of the second aluminium tube 208 of the second pole 198 is inserted into the second passageway 148 of the first pole 196 through the seal 212. The end of the first pole 196 with the first seal 204, with the second aluminium tube 208 inside of it, is then inserted into the end of the first aluminium tube 206 of the second pole 198 with the second seal 212.

The larger passageway 154 in the first pole 196 connects directly to an end of the flexible tube via a collar 214. The larger passageway 154 in the second pole 198 connects to an end of the vacuum attachment nozzle 152 via an extension tube 216.

As the poles 196, 198 are made from aluminium, they are conductive. As such the poles, 196, 198 are electrically grounded by being electrically connected to neutral in the electronic control electronics 144 in the rear housing 104. in order to ensure that the whole of elongate body 102 is grounded, ideally, the seals 204, 210, 212 are manufactured from electrically conductive material. This ensures a good electrical connection between the two poles 196, 198.

In addition or as an alternative, metal contacts 218 such as leaf springs can be located between the telescopic poles 196, 198 to ensure electrical conductivity between the poles 196, 198.

The pivot mechanism 110 will not be described with reference to Figures 4, 15 and 16.

Attached to the end of the first pole 196 in a fixed manner is an end housing 220 (see Figures 1 and 2) comprising two clam shells 222 attached to each other using screws (only one clam shell is shown in Figure 4). The pivot mechanism 110 connects the sanding head 100 to the first pole 196 via the end housing 220.

The pivot mechanism 110 comprises a fork 224 having two arms 226, a central interconnecting section 228 and a pole support section 230. The two arms 226 extend in parallel in a forward direction from the ends of the central interconnecting section 228 in a symmetrical manner.

The pole support section 230 connects to the centre of the interconnection section 228 on the opposite side of the two arms 226 and projects in a rearward direction opposite but parallel to that of the two arms 226.

Formed in each side of the gear housing 122 in a symmetrical manner are threaded apertures. The axis 232 of the of the apertures are aligned with each other and are horizontal. Formed in the ends of the two arms 226 are apertures. When the fork 224 is attached to the sanding head 100, the ends of the two arms 226 align with the apertures formed in the gear housing.

A bolt 234 is passed through each aperture in the end of the each arm 226 and screw into the threaded aperture in the side of the gear housing 122 to attach the fork 224 in a pivotal manner. The fork 224 can pivot around the bolts 234 about a horizontal sideways axis 232.

Rigidly mounted in a recess formed in the end of the pole support section 228 is the rear half of an axle 234. The axle 234 projects rearwardly. Formed in the end housing 220 is an elongate recess 236. The recess 236 extends in a direction parallel to the longitudinal axis of the first pole 196. The forward half of the axle 234 is mounted inside of the recess 236 via two bearings 240 supported by the end housing in the side walls of the recess. The bearings 240 allow the axle to rotate within the recess. The axle can rotate about an axis which is parallel to the longitudinal axis of the first pole 196 and which passes through the length of the second smaller passage 148 of the elongate body 102. This allows the fork 224, together with sanding head 100, to pivot about an axis which is parallel to the longitudinal axis of the first pole 196 and which passes through the length of the second smaller passage 148 of the elongate body 102. The axis also crosses the output axis 126 of the drive spindle.

The sanding head 100 has a centre of gravity 242. As best seen in Figure 15, the axis of pivot 232 of the fork 224 on the sanding head 100 is located forward (distance Din Figure 15) of the centre of gravity 242. Furthermore, the axis of pivot 232 of the fork 224 on the sanding head 100 100 is located forward of the drive axis 126 of the output spindle 118. This allows the sanding head 100, which can freely rotate about the bolts 234, to automatically pivot to an angular position where it is parallel to a wall when the sanding head 100 is raised by an operator.

When the plane of the platen 116 is parallel to the longitudinal axis of the elongate body 102 as shown in Figure 16, the axis of rotation of the axle is located below the centre of gravity 242 of the of the sanding head 100.

The design of the platen 116 will now be described with reference to Figures 17 and 18.

The platen 116 comprises a plastic disc 244 with a metal insert 246 located at the centre. Attached to the bottom of disk is layer made of a soft foam 248. Attached on the opposite side of the soft foam layer is a sheet of Velcro 250. The Velcro 250 is used to attach the sandpaper to the platen 116.

The platen 116 is attached to the output spindle 118 using a bolt 252. The platen 116 is circular and extends radially from the drive axis 126 in a direction perpendicular to the drive axis 126. Two sets of air holes 254, 256 are formed through the platen 116 to allow air and debris to pass through the platen 116. The first set 254 are located towards the outer edge of the platen and in a symmetrical manner around the axis 126. The holes 254 of the first set are tear shaped with the narrower end pointing towards the centre. The straight sides of the holes 254 align with the centre of the platen 116. The second set of hole 256 are located between the first set 254 and the centre of the platen 116 in a symmetrical manner. The holes 256 of the second set are smaller than those of the first set. The holes 256 of the second set are tear shaped with the narrower end pointing towards the centre. The straight sides of the holes 256 align with the centre of the plate 116.

Referring to Figure 6A, a space 258 is formed between the top of the platen 116 and the underside of the hood 112. in the present design, the size H of the space is kept to a minimum.

This ensures that the air speed above the platen 116 is kept as high as possible. If the air speed slows, entrained dust and debris will deposit on the surface of the underside of the hood 112 and therefore will build up. By keeping the air speed high, the dust remains entrained and therefore can be drawn out the flexible pipe 128 due to the suction from a vacuum cleaner.

The air flow around the rotating platen 116 is improved due to the inner circular inner wall 162 which is adjacent the outer edge of the platen 116. The inner wall 162 locates between the edge of the paten and the bristles 182 of the brush ring 132. The inner wall 162 guides the moving air in a smooth manner and minimises the amount of contact between the moving air and the bristles 182 of the brush ring 132. If the moving air were to come into contact with the bristles 182, the air flow would become non-uniform as its passes through the bristles 182.

Furthermore, the use of the inner wall 162 to separate the bristles 182 from the edge of the platen 116 minimises the amount of dust and debris that collects within the bristles 182.

The cross-sectional area of the gap 260 between the inner wall 162 and the edge of the platen 116 (shown by the hatchings 262 in Figure 68) is the same as that of the cross-sectional area of the flexible pipe 128 which in turn is the same as that of the first passageway 154 way in the two poles 196, 198.

Referring to Figure 19, the second pole 198 extends into the mount section 136 of the rear housing 104. A part 270 of the side wall first aluminium tube 206 of the second pole 198 has been removed to expose the surface of the second aluminium tube 208. The control electronics 144 are mounted in a control module. Where the part 270 of the first aluminium tube has been removed, the control module 144 is mounted inside of the first aluminium tube 206 adjacent the second aluminium tube 208. This enables heat generated by the electronic module 144 to be transferred to the second aluminium tube 208 which is a good heat conductor and transfer the heat away from the control module 144. Furthermore, during the operation of the pole sander, air is drawn through the second aluminium tube 208 by a vacuum cleaner. The air flow acts to cool the second aluminium tube 208 which in turn acts to cool the electronic module 144.

The control electronics 144 are connected directly to the motor 114 using a single electrical cable 146 which carries the wires use to provide the electrical current to the windings of the brushless motor 114. One end of the cable 146 connects directly to the control electronics 144 via a soldering tag 272 which connects to electric interface 274. The other end connects directly to the motor 114. The cable 146 is continuous with no plugs or connectors being used so as avoid interfering with the signals generated by the control electronics 144 which are sent down the cable 146 to operate the motor 114. A central section 276 of the cable 146 located inside of the two poles 196, 198 is helical to enable the length of the cable 146 in a direction parallel to the longitudinal axis of the poles 196, 198 to extend or reduce depending on the relative telescopic positions of the two poles 196, 198. When the cable 146 exit the first pole 196 and pass across the pivot mechanism 110, it locates against the side of flexible pipe 128 as shown in Figure 21. In order to maintain the position of the cable 146 relative to the flexible pipe 128, a tubular sheaf 278 surrounds both the cable 146 and the flexible pipe 128 as shown in Figures 26 and 27.

An extension tube 280 connects to the end of the second aluminium tube 208 of the second pole 198 which extends the first passageway 154 of the second pole 198 through the rear handle section 138 of the rear housing 104 and projects rearwardly of the handle section 138. A vacuum nozzle 152 is releasably attachable to the end of the extension tube 280 via a clip 282. The clip 282 comprises a first part formed on the vacuum nozzle 152 and a second part formed on the end of the extension tube 280. The first part comprises two pins 284, each pin 284 being mounted on the end of a resiliently deformable leg 286. The second part comprise two holes 288 formed through the side wall of the end of the extension tube 280 in corresponding. locations to the pins 284. To attach the vacuum nozzle 152, the legs 286 are bent inwardly so that the pins 284 can slide inside of the end of the extension tube 280 as the vacuum nozzle 152 is slid into the extension tube 280. When the pins 284 align with the holes 288, the pins 284 are biased into the holes 288 by the resilient legs 286 bending back to their original position. Whilst the pins 284 are located in the holes 288, the vacuum nozzle 152 remains attached to the extension tube 280. To detach the vacuum nozzle 152 the pins 284 are pushed back into the apertures to disengage them from the holes 288. The nozzle 152 is slid out of the extension tube 280. The vacuum nozzle 152 can be attached to the hose of a vacuum cleaner. As the nozzle 152 can be easily attached and detached, a suitable design of nozzle 152 can be chosen depending on the type of vacuum cleaner utilised. Furthermore, if the nozzle 152 breaks it can be easily replaced.

Claims

Claims 1 A handheld pole sander for sanding, polishing, grinding or rubbing a work surface comprising: an elongate body (102) having two ends; a sanding head (100) attached via a pivot mechanism (110) to a first end of the elongate body (102); an electric motor (114) mounted on the sander; wherein the sanding head (100) comprises: a hood (112) comprising a plate (156) and a peripheral wall (160) formed on the underside of the plate around the edge of the plate; an output spindle (118) which projects from the hood (112); and a brush ring (132) mounted on the underside of the plate adjacent the edge of the plate inside of the peripheral wall; wherein the electric motor (114), when activated, rotatingly drives the output spindle (118) around an axis; characterised in that the brush ring is attached to the plate via at least one leaf spring or at least one wave spring.
2 A handheld pole sander as claimed in claim 1 wherein the at least one leaf spring (186) or at least one wave spring is formed from sheet metal and is resiliently deformable in a direction perpendicular to the plane of the sheet.
3 A handheld pole sander as claimed in either of claims 1 or 2 wherein the brush ring (132) comprises a circular ring (180) and a series of bristles which extend perpendicularly from a bottom side of the ring.

3 A handheld pole sander as claimed in any of claims 1 to 3 wherein the spring is a leaf spring; wherein one end of the at least leaf spring attaches to a top side of the circular ring, the other end attaches to the plate.
4 A handheld pole sander as claimed in claim 3 wherein at least one aperture (166) is formed through the plate, wherein the at least one leaf spring extends through the at least one aperture in order for the other end to attach to a top side of the plate.
5 A handheld pole sander as claimed in any of the previous claims wherein the at least one leaf spring or wave spring extends in a direction parallel to the ring.
6 A handheld pole sander as claimed in any of the previous claims wherein the spring is a leaf spring wherein the at least one leaf spring comprises a central section located between a first end section and a second end section.
7 A handheld pole sander as claimed in claim 6 wherein the end sections (184, 190) extend in a direction parallel to the top surface of the ring (180).
8 A handheld pole sander as claimed in either of previous claims 6 or 7 wherein the central section 188 of the at least one leaf spring (186) extends upwardly at a slight angle to the plane of the circular ring (180).
9 A handheld pole sander as claimed in any of claims 6 to 8 when dependent on claim 4 wherein the central section (188) of the at least one leaf spring 186 extends through the rectangular aperture (166) A handheld pole sander as claimed in any of the previous claims wherein there is provided a circular inner wall (166) formed on the underside of the plate in close proximity to the edge of the plate inside of the peripheral wall and brush ring, the peripheral wall and inner wall forming a trough in which is mounted the brush ring.11 A handheld pole sander as claimed in claim 10 when dependent on claim 4 or 9 wherein the at least one aperture is formed through the base of the trough.12 A handheld pole sander as claimed in any of the previous claims wherein there are six leaf springs and six apertures.13 A handheld pole sander as claimed in claim 1 wherein the wave spring is a nested wave spring, a crest to crest wave spring, a single turn wave spring, an interlace wave spring or a combination of such wave springs.14 A handheld pole sander as claimed in claims 12 or 13 wherein the spring is a wave spring; wherein at least one aperture (166) is formed through the plate; wherein at least part of the wave spring extends through the at least one aperture in order for that part to attach to a top side of the plate.A handheld pole sander as claimed in claims 1, 13, and 14 wherein there is provided a circular inner wall (166) formed on the underside of the plate in close proximity to the edge of the plate inside of the peripheral wall and brush ring, the peripheral wall and inner wall forming a trough in which is mounted the brush ring.16 A handheld pole sander as claimed in claim 15 when dependent on claim 14 wherein the at least one aperture is formed through the base of the trough.