GB2482419A

GB2482419A - Tool for aligning sandpaper with a sanding plate

Info

Publication number: GB2482419A
Application number: GB1113002.8A
Authority: GB
Inventors: Jens Zieger
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 2010-07-28
Filing date: 2011-07-27
Publication date: 2012-02-01
Anticipated expiration: 2031-07-27
Also published as: CN102343542A; CN102343542B; DE102010038504B4; DE102010038504A1; GB2482419B; GB201113002D0

Abstract

A device 16 or 25 for positioning a planar, in particular flexible working medium 9, in particular sandpaper, on a working-medium carrier (7 fig. 6) such as a disc shaped sanding plate (8 fig. 6) of a power tool (2 fig. 1), in particular a hand-held power tool formed as a sanding apparatus (3 fig. 1), has a carrying part 16 or 25 for placing on and applying the planar working medium 9, the carrying part 16 or 25 being provided with positioning lugs 17 or 28 which, for applying the working medium 9 to the working-medium carrier (7 fig. 6), engage in apertures (12, 13 fig. 6) provided in the sandpaper 9 and sanding plate (8 fig. 6) and form hole pairings 14. The carrying part 16 may be circular and bent to a U-shape in use or may be similar in shape to a stamp with stamp plate 27 and handling part 26.

Description

Description Title

Device for positioning a pianar working medium The invention relates to a device for positioning a planar, in particular flexible working medium on a working-medium carrier according to the precharacterising clause of Claim 1.

Prior art

Power tools, in particular hand-held power tools, are of multifunction design, especially for the DIY sector, and to this end are also used with different working media. One field of application in this regard is the use for sanding and polishing purposes. To this end, the working-medium carrier of the normally electrically driven tool is covered with sandpaper, polishing pads or the like, for which a positionally defined association is required or at least expedient owing to the necessary matching of the shaping of the working medium and the working-medium carrier, and/or of suction and/or blowing openings passing as hole pairings through the working medium and the working-medium carrier.

Such an association is laborious particularly if the exchangeable working medium is to be adhesively fastened to the working-medium carrier, since such adhesive connections, whether they be releasable bonding connections or mechanical interlocking connections, such as for example hook-and-loop fasteners, require precise alignment immediately upon application and can scarcely be readjusted.

Disclosure of the invention

The object on which the invention is based is to provide a positioning device which enables precise alignment of the working medium with the working-medium carrier, is of simple design and preferably also facilitates the handling of the working medium during connection to the working-medium carrier.

This object is achieved according to the invention by the features of Claim 1. The subclaims specify expedient developments.

The positioning device provided for this has a carrying part for the planar, where appropriate also flexible, working medium which is to be applied on the working-medium carrier in each case, and is provided with positioning lugs which are to be aligned on the working-medium carrier and align the working medium with respect to the carrying part.

This makes it possible to place the working medium, for example in the form of sandpaper, a sanding pad, a polishing pad or the like, on the carrying part initially independently of the working-medium carrier in such a manner that, on subsequent positioning of the carrying part via the positioning lugs to be aligned on the working-medium carrier, the working medium can be placed and applied in aligned manner on the working-medium carrier via the carrying part, specifically in the final position required in each case. The working medium is thus brought up to the working-medium carrier and placed on it already exactly aligned with the final position, so that there is no need for positional corrections and it is also possible to use adhesive or catching fastening means which are provided for connecting the working medium to the working-medium carrier.

This can be achieved in a simple manner in that hole pairings corresponding to the positioning lugs and formed by apertures in the working medium and in the working-medium carrier are provided, which enable on the one hand the required alignment of the working medium with respect to the carrying part to be achieved and on the other hand the carrying part, and thus also the working medium connected to it, to be placed in a manner aligned with respect to the working-medium carrier without it being necessary for any further connection to be made between the carrying part and the working-medium carrier, and thus the positioning device can also be removed without difficulty after the working medium has been applied on the working-medium carrier.

The device for positioning according to the invention does not require any additional outlay at all regarding the design of the working medium and the working-medium carrier, particularly if corresponding hole pairings are already provided for working-related reasons for instance.

This is the case for example when such hole pairings are already provided for blowing in air onto the respective working surface on the workpiece, or else for sucking air and dust away from this working surface.

Normally, the number of hole pairings here is greater than the number of positioning lugs, so that at least with point-symmetric working carriers and corresponding circular-disc-shaped working media, such as, for example, sanding or polishing discs, suitable alignment of the carrying part with respect to the working-medium carrier is possible in an extremely simple manner.

Preferably, as the positioning lugs, at least two, in particular only two, positioning lugs spaced apart from one another are provided, which lugs preferably lie opposite one another in a plane of symmetry of the respective A preferred configuration of the positioning device results when the positioning lugs are provided on a web lying between edge parts of the carrying part and extending in particular along a diagonal of the disc-shaped, in particular circular-disc-shaped and symmetrical, carrying part, thereby also resulting in preferred possibilities of configuring the positioning device in a manner suitable for gripping and in conjunction with this where appropriate also securing the position of the working medium with respect to the carrying part in a particularly expedient manner.

In principle, it is within the scope of the invention to design the carrying part substantially in the shape of a disc and also provide a handling means in the region of the web of the carrying part, on which the positioning lugs are provided, so that the positioning device can be handled and used in the manner of a stamp.

A preferred solution according to the invention consists in creating via the edge parts, by suitable positioning of the edge parts with respect to the web, a gripping zone which, when the user grasps the edge parts on reaching over the carrying part, enables the user simultaneously to grasp the parts of the working medium which are laid against the edge parts.

In such a configuration, the carrying part becomes a U-shaped gripping part in which the edge parts are bent up towards one another with respect to the web lying therebetween, with positioning lugs extending, with respect to the web, opposite the direction in which the edge parts are erected.

Such a U-shaped configuration of the carrying part makes the positioning procedure particularly simple, since the carrying part forms practically a carrying back arched in a U-shape, in the web region of which lie the positioning lugs passing through the carrying medium laid against the carrying part, so that these lugs lie fully in the field of view also during placement on the working-medium carrier, the edge parts bent up relative to the web of the carrying part facilitating the positioning work owing to their alignment parallel to the longitudinal direction of the web.

In such a configuration of the carrying part with edge parts bent up in a U-shape relative to the web, the positioning device forms practically a mounting folding template for the working medium, via which the working medium, for the mounting, is initially bent to the U-shape corresponding to the shape of the carrying part, so that the carrying part with the working medium lying on it can be brought, in a manner pivoted with respect to an imaginary axis lying in the longitudinal direction of the web, up to the working-medium carrier obliquely with respect to the plane in which the latter extends, thus making it easier to accurately place the positioning lugs on the apertures provided for the latter in the working-medium carrier without resulting in contact between the working medium and the working-medium carrier before the positioning location is reached. Catching or clinging between the working medium and the working-medium carrier during the positioning is thus also prevented, and this results only when the positioning lugs aligned with the apertures in the working-medium carrier are inserted into these apertures.

By means of the invention, overall a mounting method for the correct positioning of a pliant and flexible working medium on a planar working-medium carrier is thus also provided, in which the working medium is initially bent, via a carrying part formed as a U-shaped template, to the U-shape and, when bent in such a manner, is aligned with the working-medium carrier via positioning lugs provided in the region of the web of the carrying part and to be inserted into receptacles of the working-medium carrier, and is applied on the latter.

Further advantages and expedient embodiments can be found in the claims, the description of the figures and the drawings, in which: Fig. 1 shows in a schematised illustration, as an example of a hand-held power tool, a random orbit sander with a working-medium carrier in the form of a sanding plate, on which sandpaper as the working medium is adhesively applied, Fig. 2 shows an isolated perspective illustration of a positioning device according to the invention for the positionally correct application of a planar, in particular flexible, working medium on a working-medium carrier, the positioning device being formed in one piece and having a carrying part for the working medium, and positioning lugs provided on the carrying part, via which lugs the working medium is to be aligned with respect to the positioning device and the positioning device is to be aligned with respect to the working-medium carrier, Fig. 3 shows, in a view from below -arrow III -and a planar illustration, the positioning device according to Fig. 2, Fig. 4 shows, again in perspective, a sandpaper in the form of a circular disc as the working medium, which has on a hole circle a number of apertures, two of which are provided diagonally opposite one another in congruence with respect to the longitudinal-centre web of the carrying part, the edge parts of which is bent up in a U-shape, in accordance with the illustration of Fig. 1, Fig. 5 shows an illustration corresponding to Fig. 4 with the working medium, formed by the sandpaper, laid against the bent-up edge parts of the carrying part and overlapping the web, Fig. 6 shows the sanding plate, as the working-medium carrier, in a view from below with the working medium laid via the carrying part against the sanding plate as the working-medium carrier and properly aligned for mounting, Fig. 7 shows an illustration corresponding to Fig. 6, in which the working medium formed by the sandpaper has been transferred from the laid-against position with respect to the carrying part according to Fig. 6 into the working position with respect to the working-medium carrier, in which working position the sandpaper has been applied adhesively, for example via a hook-and-loop connection, to the working-medium carrier, and the carrying part can thus be removed from its position aligned with respect to the working-medium carrier after the working medium has been transferred to the working-medium carrier, and Fig. 8 shows a further embodiment of a positioning device according to the invention in a perspective view of the disc-shaped carrying part thereof, which is provided with positioning lugs.

Illustrated in Fig. 1, placed on a workpiece 1, as an example of a hand-held power tool 2, is a random orbit sander 3 of known basic design which is electrically driven, indicated by the power cord 4, and which is to be operated with dust suction-extraction, as illustrated symbolically by a suction-extraction connection 5, which can be connected for example to a dust collection bag 6.

In the illustrated embodiment as a random orbit sander 3, the hand-held power tool 2 has a working-medium carrier 7 in the form of a sanding plate 8 which carries the working medium 9 in the form of a circular sanding sheet 10 consisting of sandpaper. The working medium 9 is adhesively connected to the working-medium carrier 7, the adhesive connection preferably being designed in the manner of a hook-and-loop connection, consisting of barb-shaped fastening members provided on the one hand and of loop-shaped fastening members provided on the other hand. When these fastening members come into contact as soon as the working medium 9 -which is exchangeable for reasons of wear in any case -is placed on the working-medium carrier 7, the fastening members interlock, which means that the working medium 9 has to be correctly positioned with respect to the working-medium carrier 7 straightaway, since subsequent alignment and correction of the initial position is virtually impossible owing to the interlocking connection.

Positionally correct alignment is important, however, because additional vibrations occur with incorrect positioning and because the working medium 9 and the working-medium carrier 7, as also shown in Figs. 4 to 7, are normally provided with hole-type apertures 12, 13 which form as hole pairings 14 suction-extraction openings for the abraded material resulting during the work. The hole pairings 14 can also be used correspondingly as blowing openings. In both cases, inexact overlying correspondence of the edges of the apertures 12, 13 means that the free flow cross-section is reduced and thus poorer sucking or blowing performance is achieved.

In order to achieve proper positioning of the working medium 9 with respect to the working-medium carrier 7, use is made, according to the invention, of a positioning device 15 consisting of a carrying part 16 and of positioning lugs 17 provided on the carrying part 16. The carrying part 16 has, as shown in Fig. 2, a U-shaped basic shape with edge parts 19, 20 forming legs of the U-shaped basic shape which are bent up on both sides of a central web 18.

In the view from below according to Fig. 3 with the edge parts 19, 20 swung into the plane of the drawing, the carrying part 16 has a shape preferably corresponding to the shape and size of the working medium 9, the web 18 extending along a diagonal between the edge parts 19, 20.

The positioning lugs 17 are provided on the web 18. In particular regarding good handleability of the positioning device 15, the edge parts 19, 20 are provided with cutouts 21 running transversely with respect to the web 18, also resulting in a material-saving construction for the positioning device 15. The positioning lugs 17 engage in the diagonally mutually opposite hole-type apertures 12 of the working medium 9, so that the web 18 forms along the diagonal extent over the centre of the working medium 9 a carrying back, against which, as illustrated in Fig. 5, the edge regions of the working medium 9 can be laid, as soon as the positioning lugs 17 of the carrying part 16 are inserted into the corresponding apertures 12 of the working medium 9.

Fig. 5 shows that, in this state, the edge parts 19, 20 of the carrying part 16 form bearing surfaces for the edge regions of the working medium 9 lying on both sides of the web 18, when these edge regions are laid against the carrying part 16, in which laid-against state preferably at least individual ones of the apertures 12 in the working medium 9 lie in congruence with apertures 21 in the edge parts 19, 20, so that the user of the positioning device 15 is able to get a good grasp on the carrying part 16 with the working medium 9 laid-against the latter. From a practical point of view, the bent-up edge parts 19, 20 thus form a hold against which the correspondingly bent-up working medium 9 is pressed when the user grasps it, so that a unit of good handleability formed of the carrying part 16 and the working medium 9 is obtained. This unit is placed on the working-medium carrier 7, as illustrated in Fig. 6, bringing about initially substantially only a line contact in the longitudinal direction of the web 18 with respect to the working-medium carrier 7, in accordance with the diagonal extent of the web 18 with the positioning lugs 17 provided thereon and the hole pairings 14 existing between the working-medium carrier 7 and the working medium 9, and the alignment of the latter with the carrying part 16. Proceeding from this basic alignment, the working medium 9 is laid by its edge regions against the working-medium carrier 7, the desired positionally fixed association of the working medium 9 with respect to the working-medium carrier 7 being achieved via the hook-and-loop connection 11. Proceeding from this, i.e. after the working medium 9 has been placed on the working-medium carrier 7, in accordance with the illustration in Fig. 7, the positioning device 15 can be removed from the working-medium carrier 7 and is thus available for a next corresponding mounting procedure.

Fig. 8 illustrates a further possible configuration of a positioning device 25, the positioning device 25 in this solution being formed as a stamp, so to speak, with handling part 26 and stamp plate 27 on which positioning lugs 28 are provided. The positioning lugs 28 lie in congruence with perforations, as formed for example by the apertures 12, 13 -as hole pairings -in a working medium and a working-medium carrier, so that when a working medium is placed on the stamp plate 27, the positioning device 25 with the placed-on working medium can be placed via the positioning lugs 28 in aligned manner on the working-medium carrier. In order that the working medium 9 placed on the positioning device 25 does not come into contact with the working-medium carrier before the alignment with respect to the working-medium carrier is achieved, it has proved expedient for the positioning lugs 28 to have a greater height in their axial extent than the placed-on working medium. Thus, the sought positioning is to be achieved before an adhesive connection can take place between working medium and working-medium support, which can be obtained once again for example by a hook-and--loop connection 11.