GB2415650A

GB2415650A - Motorised hand-held grinding tool

Info

Publication number: GB2415650A
Application number: GB0512417A
Authority: GB
Inventors: Steffen Wuensch
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 2004-06-24
Filing date: 2005-06-17
Publication date: 2006-01-04
Anticipated expiration: 2025-06-17
Also published as: CN1712186A; GB0512417D0; DE102004030450A1; CN100553881C; GB2415650B

Abstract

An abrasive sheet is held on a hand-held grinding tool (eg. a rotary or orbital sander) by a holder 100. The holder comprises a front clamp 102 a rear pincer clamp 103 and a clip 104, having arm sections 105a, 105b and a transverse section 106 in the same plane as the arms. The front clamp is eccentrically pivoted on baseplate 101 and engages with clip 104 via lug 108. To open the holder (and thus release the abrasive sheet), the user pushes roughened actuator pad 110, which depresses lever 109 and disengages lug 108 from clip 104.

Description

24 1 5650 Motorised Hand-held Grinding Tool

Prior Art

The invention is based on a motorised hand-held grinding tool with the generic features of claim 1.

Motorised hand-held grinding tools which provide an automatic tensioning system with a locked clip construction

are already known from the prior art.

In these known motorised hand-held grinding tools, however, the clip construction has a complex shape, so that it is costly to manufacture. Furthermore, with these known motorised hand-held grinding tools the clamping of an abrasive sheet still requires several movements, so that in this case it would be desirable if it were operated more easily and in a less time-consuming manner.

Advantages of the invention In contrast, a motorised hand-held grinding tool according to the invention with the features of claim 1 has the advantage that the clip construction has a simpler shape.

As the transverse element of the clamping clip is constructed as a simple, straight line and thus is arranged in a plane with the clamping arms, the clamping clip can be particularly easily bent from a single piece of wire. This reduces the manufacturing costs of a motorised hand-held grinding tool according to the invention.

Preferably, the motorised hand-held grinding tool further comprises a clamping clip lock with an actuation lever, the actuation lever comprising a catch in the centre for locking the clamping clip. It is particularly advantageous if the actuation lever comprises a contact surface for releasing the clamping clip. This contact surface represents additional ease of handling when opening the clamping device to remove a worn abrasive sheet. In fact, a user merely has to press on the contact surface to open the clamping device. The clamping clip then springs automatically out of the catch means. Thus only a brief pressing action is necessary to open the clamping device.

The contact surface provided makes this particularly simple, as it indicates to the user precisely which point has to be pressed. The ergonomic contact surface also ensures that the user can exert appropriate pressure at the correct point.

With motorised hand-held grinding tools according to the invention with long clamping clip designs, it is also advantageous if the abrasive sheet holder comprises one or more projections laterally. As a result, oscillatory movement of the clamping clip is prevented when the motorised hand-held grinding tool is operated.

Further advantageous embodiments of the invention are the subject of the subclaims.

Drawings An embodiment of the invention is described in more detail

in the following description with reference to the

accompanying drawings. The only Figure shows a perspective view of a clamping device according to the invention in the clamped state.

The clamping device 100 shown in the Figure comprises an abrasive sheet holder or even an abrasive plate 101 which carries all individual parts of the clamping device 100.

The clamping device 100 has a front clamping device 102 and a rear clamping device 103. The clamping devices 102 and 103 serve to clamp and tension the front and rear end respectively of an abrasive sheet. The front clamping device 102 is constructed as an eccentric abrasive paper clamp with a bias spring. The rear clamping device 103 is constructed as pincers.

A main component of the clamping device 100 is a clamping clip 104. In this connection the rear part of the clamping clip 104 is associated with the rear clamping device 103, whereas the front part of the clamping clip 104 is associated with the front clamping device 102. The clamping clip 104 consists of a single correspondingly curved piece of wire.

The clamping clip 104 comprises two clamping arms 105a and 105b which are joined to one another by a transverse element 106. The transverse element 106 is a simple, straight, uncurved portion of wire of the clamping clip 104. In this connection the transverse element 106 is located in the same plane at right angles to the two clamping arms 105a and 105b.

The front clamping device 102 comprises two lateral locating surfaces or even raised portions 107a and 107b, which serve to locate and guide the clamping clip 104. The raised portions 107a and 107b engage respectively in the right angle which is formed by the join between the respective clamping arm 105a and 105b and the transverse element 106.

The clamping clip 104 is held in position on the front clamping device 102 by a lock or even a catch, to be more precise a locking lug 108. This takes place by the transverse element 106 engaging under the locking lug 108.

The locking lug 108 is centrally attached to a resilient actuation lever 109. An elliptical contact surface 110 is arranged on the actuation lever 109, above the locking lug 108. The contact surface 110 is roughened, in order to ensure a better grip for the user's finger. The contact surface 110 is constructed obliquely to the perpendicular axis of the actuation lever 109.

An additional support 111 is furthermore arranged on the abrasive sheet holder 101 which serves to support and guide the clamping arm 105b. This projection 111, though not shown, is also provided on the opposing face to support the clamping arm 105a.

The mode of operation of the clamping device 100 shown in the Figure will be explained hereinafter.

The abrasive sheet is inserted and clamped in the manner known from the prior art. Nevertheless, the following important functions emerge with the illustrated clamping device 100: In the embodiment shown, the abrasive sheet is already tensioned before snapping the clamping clip 104 into the front clamping device 102.

By pressing the clamping clip 104 into the lock 108, the spring force of the clamping clip 104 is additionally used to assist the eccentric tension of the front clamping device 102.

To open the clamping device 100 and to remove a worn abrasive sheet the contact surface 110 of the actuation lever 109 is pressed, over the transverse element 106 of the clamping clip 104, so that the clamping clip 104 springs out of its catch means. As a result, the pincers of the rear clamping device 103 are released and the paper springs out of the rear clamping device 103.

As the transverse element 106 of the clamping clip 104 is realised as a straight, cylindrical portion, the clamping clip 104 is particularly simple to manufacture. In particular, it is not necessary to provide the transverse element 106 with additional curved and bent portions.

The transverse element 106 is held in the clamped state in a particularly simple manner by a single locking lug 108.

The clamping clip 104 can be particularly easily released from its catch means by the contact surface 110. The user knows exactly where to press to remove a worn abrasive sheet. Pressing is particularly simple as the contact surface 110 is ergonomic at the correct point and 'finger- sized'.

List of Reference Numerals Clamping device 101 Abrasive plate 102 Front clamping device 103 Rear clamping device 104 Clamping clip Clamping arms 106 Transverse element 107 Raised portions 108 Locking lug 109 Actuation lever Contact surface 111 Projection

Claims

Claims 1. Motorised hand-held grinding tool, in particular rotary grinder,

with an abrasive sheet holder (101) and with clamping means (102, 103) for securing an abrasive sheet to the abrasive sheet holder (101), the clamping means (102, 103) comprising a clamping clip (104) with two clamping arms (105a, 105b) joined by a transverse element (106), characterized in that the transverse element (106) and the clamping arms (105a, 105b) are arranged in one plane.
2. Motorised hand-held grinding tool according to claim 1, further characterized by a clamping clip lock (102) with an actuation lever (109), the actuation lever (109) comprising a catch (108) in the centre for locking the clamping clip (104).
3. Motorised hand-held grinding tool according to claim 2, characterized in that the actuation lever (109) comprises a contact surface (110) for releasing the clamping clip (104).
4. Motorised hand-held grinding tool according to claim 3, characterized in that the contact surface (110) is arranged above the catch (108).
5. Motorised hand-held grinding tool according to any of claims 2 to 4, characterized in that the catch (108) is a locking lug. l
6. Motorised hand-held grinding tool according to any of the preceding claims, characterized in that the abrasive sheet holder (101) comprises a projection (111) laterally.

A motarised hand-held grinding tool substantially as herein described with reference to the accompanying drawing.