GB2333981A

GB2333981A - A power tool attachment.

Info

Publication number: GB2333981A
Application number: GB9802701A
Authority: GB
Inventors: Julien Jean Louis Lankry
Original assignee: BROOKDALE TOOL CO Ltd
Current assignee: BROOKDALE TOOL CO Ltd
Priority date: 1998-02-10
Filing date: 1998-02-10
Publication date: 1999-08-11
Anticipated expiration: 2018-02-10
Also published as: GB9802701D0; GB2333981B

Abstract

A power tool attachment, for example, for a hand-held power drill and which may be faced with an abrasive or polishing material which may be applied to a workpiece whilst being rotated by the power tool, and comprising a rigid disc (10) and an attachment spindle (8) flexibly attached to the disc (10) by means of a helical spring (24) and by a rubber disc (17). Relative tilting movement of the spindle (8) and the disc (10) is controlled and adjusted by a threaded collar (27) mounted on the spindle (8). A casing member (25) having a central aperture into which a part of the collar (27) may become located to prevent such relative movement, encloses the spring (24) and disc (17) and their attachment to the disc (10).

Description

A POWER TOOL ATTACHMENT THIS INVENTION concerns a power tool attachment of the kind which may be inserted into, for example, the chuck of a hand-held electric drill, and used to provide a rotary sanding or polishing action. The device consists essentially of a spindle for attachment to the power tool, and a disc which may be faced with an abrasive or polishing material and which may be applied to a workpiece while being driven in rotation by the power tool at a speed of, for example, 1200 revolutions per minute.

Use of a power tool attachment of this kind is facilitated if the abrasive or polishing surface may be tilted with respect to the rotational axis of the tool. Conventionally, such attachments comprise a flexible rubber disc to which a drive spindle is attached and onto the outer face of which an abrasive or polishing material is placed. The natural resilience of the disc itself provides adequate flexibility, but one form of attachment is now known incorporating a substantially rigid disc, and it is an object of the present invention to provide an improved degree of flexibility to such rigid discs.

According to the present invention there is provided a power tool attachment comprising a disc which may be faced with an abrasive or polishing material, and a spindle attached to the disc for connection to a rotary power tool; characterised in that the spindle comprises at least two axially aligned portions with resilient means providing limited articulation between the portions; and in that the spindle is attached to the disc through the intermediary of a resilient member which itself is fixedly attached to the disc and to the spindle.

An embodiment of the invention will now be described, by way of example only, with reference to the accompanying drawing which is a vertical cross-section through a power tool attachment made in accordance with the invention.

Referring now to the drawings, a power tool attachment comprises a disc generally indicated at 10 and consisting of a first part 11, circular in plan and preferably made from a rigid plastics material, and a second part 12 of a similar shape and material which is attached to part 11 by an interference fit. The part 12 has a plain circular bottom face to which is bonded a self-adhesive foamed plastics disc 13 bearing on its remote face one part 14 of a touch and close fastener of the type, for example, known by the trade mark VELCRO.

The first circular part 11 of the disc 10 has a stepped inner flange 15 defining a central aperture 16. Attached to the underside of flange 15 is a flexible disc 17 preferably of rubber which is bolted as at 18 with washers 30 to the flange 15 in four positions around its circumference.

A spindle generally indicated at 8 consists of first and second axially aligned separate parts 19 and 20. The first and upper part 19 has a plain shank 21 for insertion into the chuck of a power tool, and an aligned threaded portion 22 which extends downwardly into abutment with the spindle part 20, the latter being bolted as at 23 to the rubber disc 17. The abutting faces of the parts 19 and 20 of the spindle 8 are domed to enable the parts to be tilted relative to each other. Separation and excessive tilting is prevented by a strong helical spring 24 which surrounds and is frictionally engaged upon adjacent threaded regions of spindle parts 19 and 20.

A rigid plastics casing member 25 is an interference fit on a side wall 26 of the disc part 11 and serves to enclose the lower region of the spindle and its attachment to the rubber disc 17. A threaded adjusting collar 27 engages the threaded portion 22 of the upper spindle part 19 and includes a reduced diameter shoulder 28 which (as shown) is located within a complementary aperture in the top of the casing 25.

Engagement of the reduced diameter shoulder 28 within the aperture casing serves, substantially, to prevent relative tilting of the upper and lower parts of the spindle 8 so that the whole device is generally rigid.

By unscrewing the collar 27 such that the reduced diameter shoulder 28 is extracted from the casing aperture, a degree of tilting movement of the disc relative to the spindle is permitted by the helical spring 24 and rubber disc 17. Thus, the disc is somewhat flexibly mounted on a power tool, which ensures ease of use particularly when operating on a workpiece having a curved surface.

The spring 24 is frictionally engaged on and between the spindle 8 and the disc 10.

In this embodiment, a greater degree of flexibility between the spindle and the disc is provided by the combination of spring 24 and rubber disc 17, when compared with conventional arrangements having either a split spindle or rubber disc alone.

However, the flexibility can be controlled by screwing down the collar 27 so that the reduced diameter shoulder 28 engages within the central aperture within the casing 25 thus reducing or preventing relative tilting movement between the spindle and the disc.

It is not intended to limit the invention to the example described. For example, the rubber disc 17 may be frictionally attached to the flange 15 such as by integral rubber pins engaged within apertures in the flange.

Claims

CLAIMS 1. A power tool attachment comprising a disc which may be faced with an abrasive or polishing material, a spindle attached to the disc for connection to a rotary power tool, characterised in that the spindle comprises at least two axially aligned portions with resilient means providing limited articulation between the portions; and in that the spindle is flexibly attached to the disc through the intermediary of a resilient member which itself is fixedly attached to the disc and to the spindle.
2. A power tool attachment according to Claim 1, wherein the said resilient means is frictionally engaged with the spindle.
3. A power tool. attachment according to Claim 1 or Claim 2, including means to adjust the relative tilting of the spindle and the disc.
4. A power tool attachment according to Claim 3, wherein the adjustment means is a collar threadedly engaged on the spindle and adapted to become engaged with a part of the disc.
5. A power tool attachment according to Claim 4, wherein said part of the disc comprises a casing member enclosing the resilient means and the resilient member.
6. A power tool attachment according to any preceding claim, wherein the disc comprises upper and lower parts connected together by an interference fit, the lower part providing a flat face for attachment thereto of said abrasive or polishing material.
7. A power tool attachment according to Claim 1, wherein said resilient means is a helical spring frictionally engaged with the separate parts of the spindle.
8. A power tool attachment according to Claim 1, wherein said resilient member is a flexible disc for example of rubber and bolted to the disc.