GB2260721A

GB2260721A - Sanding tool with dust collector

Info

Publication number: GB2260721A
Application number: GB9222465A
Authority: GB
Inventors: R J Stevens
Original assignee: STEVENS FIBREGLASS Ltd
Current assignee: STEVENS FIBREGLASS Ltd
Priority date: 1991-10-24
Filing date: 1992-10-26
Publication date: 1993-04-28
Also published as: GB9222465D0

Abstract

A motor-driven sanding tool having a sanding disc 4 is provided with a shroud 7 which surrounds the disc to collect dust and exhaust it through a conduit to a collection bag. No external vacuum source is required by virtue of radial blades 22 provided on the tool shaft to enhance air flow to the conduit. A ball joint 18 and a spring 16 allow universal movement of the shroud relative to the tool body 1. <IMAGE>

Description

SANDING TOOL DUST COLLECTOR The invention relates to a dust collector for a handheld sanding tool. Such a tool comprises a motor which drives an abrasive disc. A considerable amount of dust is produced in sanding materials, particularly such as wood, plastics, glass fibre etc. The dust is a nuisance and a health hazard. The invention provides a dust collector for a tool of the kind described.

According to the invention there is provided a dust collector for a hand-held sanding tool, the tool comprising a motor which drives an abrasive sanding disc, the sanding disc presenting a substantially flat sanding face to a surface to be sanded, and the dust collector comprising a frame adapted to be fixed to the tool; a shroud mounted on the frame by a mounting arrangement so as to encompass the sanding disc, the shroud having a peripheral rim which makes contact with the surface being sanded so as to surround the sanding face; an extractor conduit coupled to the shroud whereby sanding dust may be exhausted therefrom, the said mounting arrangement being such as to give a universal and resilient movement of the shroud with respect to the frame; and on the disc or on a rotor coupled to the disc, radial vanes arranged to enhance flow of air from the centre to the periphery of the disc.

It is found that the provision of radial vanes coupled with the disc furnishes adequate dust exhaustion without the expense and complication of an external vacuum pump.

A hand-held sander differs from a fixed sander or grinding wheel in that it is generally run over a surface to be sanded, and the tool is tilted to apply differential sanding pressures as the operation proceeds. In order to accommodate tilting and maintain an effective seal for the dust to be collected, the shroud in accordance with the invention is resiliently pressed against the surface and is allowed to tilt with respect to the frame, thereby maintaining a seal in spite of tilting of the frame and tool.

The frame and shroud may be mounted with respect to each other by any suitable resilient and universal means. It is envisaged, for example, that a gimbal arrangement might be used. However, a preferred arrangement includes a ball joint which allows universal movement of the shroud and includes a relatively large single helical spring mounted coaxially with the sanding disc and compressed between the frame and the shroud at its ends.

It is found expedient to provide that the conduit for exhausting the dust couples with the shroud via one or more apertures at the shroud periphery. This takes advantage of the fact that air and dust is flung by centrifugal action to the outside of the shroud volume and thereby exhausted automatically, which effect is enhanced by the radial vanes. Air flow through the shroud may be enhanced by providing inlet apertures near the centre.

The invention will further be described with reference to the accompanying drawings of which: Figure 1 is a perspective view of a hand-held sanding tool with a dust collector according to the invention; Figure 2 is a cross sectional view of the tool and dust collector of Figure 1; and Figure 3 is a part-sectional view of the tool from below.

Referring to the Figures there is shown a handheld sanding tool which comprises a housing 1 which contains an electric motor and a gear box at 2 whereby drive is transmitted to a shaft 3 which carries at its end a sanding disc 4.

A shroud 7 is mounted by virtue of a ball joint 8 to encompass the sanding disc 4 and has a rim 9 which surrounds the disc and which is provided with a sealing fabric insert 10. The shroud has an outlet 11 at its periphery which is coupled by a conduit 12 to an outlet pipe 14. Pipe 14 is adapted to be connected to a dust collection bag (not shown). It will be seen that the shroud constitutes a safety guard as well as a dust collector.

Figure 2 shows in detail the mounting arrangement of the shroud with respect to the frame. The frame is cup-shaped and the shroud has a spring seat 15. A single relatively large coil spring 16 is held in compression between the cup frame and the spring seat 15 and this affords both the axial resilient pressure and allows tilting of the shroud. The shroud is mounted by way of a sliding grip 17 on a ball 18.

Ball 18 slides on a hollow shaft 19 through which the drive shaft 20 passes. This arrangement provides universal pivoting for the shroud as it is urged against the workpiece by spring pressure. The shroud is held in place in its fully extended position by virtue of a stop ring 21.

Sanding can proceed in the normal way with the tool being tilted to adjust to the shape of the work piece. The coupling arrangement will maintain the seal 10 in contact with the work piece surface.

Because of a centrifugal impelling action imparted to the air and dust by rotation of the disc 4, it is found that dust is thrown into the conduit.

This centrifugal impeller action is enhanced by radial fins 22 on a disc 23 which rotates with the sanding disc. The fins are angled to the shape of inclined blades which give an axial component of airflow away from the shroud seal. Further enhancement of air flow may be provided by inlet apertures near the centre of the shroud. These are optional and are shown by way of example only at 24.

Claims

1. A dust collector for a hand-held sanding tool, the tool comprising a motor which drives an abrasive sanding disc, the sanding disc presenting a substantially flat sanding face to a surface to be sanded, and the dust collector comprising a frame adapted to be fixed to the tool; a shroud mounted on the frame by a mounting arrangement so as to encompass the sanding disc, the shroud having a peripheral rim which makes contact with the surface being sanded so as to surround the sanding face; an extractor conduit coupled to the shroud whereby sanding dust may be exhausted therefrom, the said mounting arrangement being such as to give a universal and resilient movement of the shroud with respect to the frame; and, on the disc or on a rotor coupled to the disc, radial vanes arranged to enhance flow of air from the centre to the periphery of the disc.

2. A dust collector as claimed in Claim 1 wherein the radial vanes are angled to give an axial component of airflow away from the shroud seal.

3. A dust collector as claimed in Claim 5 or Claim 6 wherein inlet apertures are provided near the centre of the shroud.

4. A dust collector as claimed in Claim 1 wherein the mounting arrangement comprises a ball joint which allows universal movement of the shroud, and a helical spring mounted co-axially with the sanding disc and compressed between the frame and the shroud at its ends.