EP2070651A1 - Grinding plate and abrasive disc - Google Patents

Abstract

The plate has dust suction openings (16, 17) and dust outlet openings (20) arranged at a lower side (12) and an upper side (19), respectively. The suction openings are connected with the openings (20) via suction channels (18). Air inflow openings (21) are arranged at the lower side outside a central area (6) and connected with an environment in a condition fixed to a grinding machine via inflow channels. The openings (21) are arranged in an operative area of the suction openings such that a cross flow from the openings (21) to the suction openings is formed at the side (12) during operation.

Description

The invention relates to a sanding pad for a hand-held, motor-driven grinding machine, wherein the sanding pad is fastened with its central portion of the grinding machine and in the attached state during operation performs a rotating and / or orbital motion and wherein the sanding pad at its operation during the For dusting the workpiece facing bottom dust extraction has, which are connected via extending in the sanding plate suction with arranged on the sanding machine grinding disc top dust exit openings, so that the resulting during grinding sanding dust can be removed by a machine-side dust extraction. The invention further relates to an abrasive for use on such a sanding pad.

For grinding a workpiece, an abrasive in the form of an abrasive sheet is releasably secured to the underside of the sanding pad. This is most easily done by means of a Velcro fastener. A Velcro fastener is usually formed in two parts, wherein on a closure part connecting parts with hook shape, mushroom shape, arrow shape, horn shape or the like are arranged, which cooperate binding with a corresponding loop or loop material of the other closure part. The two Closure parts each form a Velcro adhesive layer, which is arranged on the sanding pad underside or on the sanding sheet, so that the sanding sheet has to be placed only on the underside of the sanding pad and pressed against it. To remove the sanding sheet this is simply withdrawn from the sanding pad against the holding force exerted by the Velcro fastener.

The extraction of the resulting dust during grinding is carried out in the usual way through the suction and suction channels of the sanding plate. The associated sanding sheet has a hole pattern corresponding to the dust extraction openings of the sanding pad bottom side.

As practice has shown, during suction, a portion of the dust enters the parting plane between the sanding pad and the sanding sheet, i. between the two Velcro pads, so that it comes to the formation of so-called dust nests. These dust nests affect the flatness of the grinding plate and thus the quality of grinding. Furthermore, the Velcro pads can be added by the dust, so that the adhesion deteriorates or disappears in places.

Proceeding from this, the present invention seeks to provide a sanding pad and an abrasive, in which the occurrence of dust accumulation between the sanding pad and attached to this abrasive is counteracted.

This object is achieved in that a plurality of Luftzuströmöffnungen is arranged on the sanding pad bottom outside the central sanding pad area, which in the sanding plate separately from the suction channels extending inflow channels are connected in the attached to the grinding machine state off the dust extraction with the environment, the Luftzuströmöffnungen are arranged in the effective range of Staubabsaugöffnungen, such that forms a transverse flow from the Luftzuströmöffnungen to the Staubabsaugöffnungen during operation on the sanding pad bottom. To solve the problem, an abrasive for use on such a grinding plate is also provided.

The suction force exerted by the grinding machine through the suction channels of the grinding disc not only acts on the workpiece surface but also in the parting plane between the grinding disc and the abrasive sheet, i. between the two Velcro pads, and exerts on the entering between the Velcro pads or there dust particles one of these leading into the suction duct power. This is made possible by the on the one hand outward into the environment and on the other hand via the Luftzuströmöffnungen on the sanding pad underside opening inflow channels through which ambient air can flow into the parting plane between the two Velcro pads, so that said crossflow can arise and maintained and the Dust particles get into the suction channels.

In this way, the formation of dust nests between the two Velcro pads is avoided or at least reduced. The measures provided for this purpose are simple and inexpensive to implement, since only the opening on the one hand into the open and on the other hand on the sanding pad bottom opening out at the air inlet openings inflow channels must be attached.

Advantageous embodiments of the invention are specified in the subclaims.

Figur 1

den strichpunktiert angedeuteten Umriss einer Schleifmaschine, an der ein im Schnitt gemäß der Schnittlinie A-A in Figur 3 dargestellter Schleifteller gemäß vorliegender Erfindung befestigt ist,

Figur 2

den Schleifteller nach Figur 1 im gleichen Schnitt in vergrößerter Darstellung ohne die Schleifmaschine,

Figur 3

den gleichen Schleifteller in Draufsicht gemäß Pfeil III in Figur 2,

Figur 4

das Unterteil des Schleiftellers gemäß den Figuren 1 bis 3 ebenfalls im der Schnittlinie A-A entsprechenden Schnitt,

Figur 5

das Schleifteller-Unterteil gemäß Figur 4 in Draufsicht gemäß Pfeil V,

Figur 6

den gleichen Schleifteller in der Figur 3 entgegengesetzter Unteransicht und

Figur 7

ein an der Schleifteller-Unterseite zu befestigendes Schleifmittel in Gestalt eines Schleifblattes in Draufsicht.

An embodiment of the invention will be explained in detail below with reference to the drawings. Show it:

FIG. 1

the dash-dotted line outline of a grinding machine, on which a section along the section line AA in FIG. 3 attached sanding plate is attached according to the present invention,

FIG. 2

after the sanding pad FIG. 1 in the same section in an enlarged view without the grinding machine,

FIG. 3

the same sanding plate in plan view according to arrow III in FIG. 2 .

FIG. 4

the lower part of the sanding pad according to FIGS. 1 to 3 also in the section line AA corresponding section,

FIG. 5

the sanding pad base according to FIG. 4 in plan view according to arrow V,

FIG. 6

the same sanding pad in the FIG. 3 opposite bottom view and

FIG. 7

a to be attached to the sanding pad underside abrasive in the form of an abrasive sheet in plan view.

At the FIG. 1 schematically resulting hand grinder is a disc sander, the one Machine head 2, to which a motor housing 3 connects, in which an unillustrated drive motor is housed. In this case, the motor housing 3 is arranged and shaped so that it can serve as a handle for holding the grinding machine. With the other hand you can hold the machine head 2 and press down against a workpiece to be ground.

The machine head 2 contains a driven by the drive motor forth drive unit, of which only a stripping section 4 is roughly indicated by dash-dotted lines.

The grinding is done by means of a grinding plate 5, which in the present case has a circular shape and releasably secured with its central portion 6 on the grinding machine 1 and thereby drivingly connected to the driven part 4. During operation, the sanding pad 5, depending on the type of grinding machine 1, performs a rotating and / or circular movement. In the case of only a rotating grinding plate is a rotary grinder, in the case of a circular motion exporting grinding disc to an eccentric disc grinder.

In the illustrated embodiment, the sanding pad 5 has a central passage opening 7 with which the sanding pad 5 is placed on the end region of the stripping section 4 protruding from the sanding machine 1. In this case, the driven part 4 has an end-side threaded pin 8 of smaller diameter, which is associated with a tightening nut 9. To attach the sanding pad 5, the driven part 4 is inserted with the threaded pin 8 in the through hole 7 (the tightening nut 9 is still missing at this time) until the annular shoulder 10 on which the threaded pin 8 begins, at a radially into the through hole 7 projecting Tightening ring part 11 of the grinding plate 5 is applied. Then you screwed from the opposite side, the tightening nut 9 on the tightening the ring section 11 by cross-threaded spigot 8 and clamps the tightening nut 9 against the ring section 11th

It is understood that the attachment of the sanding plate can also be done in other ways.

At the in the fixed state of the grinding machine 1 facing away from and during operation of the workpiece to be ground (not shown) facing bottom 12 of the grinding plate 5, an abrasive in the form of an abrasive sheet 13 is releasably secured, with which the workpiece is grinding processed. In FIG. 1 the abrasive sheet 13 is indicated only by a dot-dash line. In FIG. 2 the abrasive sheet 13 is shown in addition to the sanding pad 5, for reasons of clarity, however, at a distance from the sanding pad bottom 12th

The detachable attachment of the sanding sheet 13 to the sanding pad bottom 12 by means of a two-piece, formed by two Velcro pads 14, 15 Klettenhaftverschlusses, of which one Klettenhaftbelag 14 on the sanding pad bottom 12 and the other Klettenhaftbelag 15 on the upper side facing the abrasive sheet 13th is arranged. To attach the sanding sheet 13 this is placed on the sanding pad bottom 12 and pressed against the sanding pad 5, so that the Velcro fastener is effective. To remove the sanding sheet 13 this is simply pulled away from the sanding pad 5.

Velcro fasteners are well known, so that a more detailed description at this point is unnecessary.

The dust created when grinding a workpiece can be extracted. For this purpose, the sanding pad 5 on its underside 12 Staubabsaugöffnungen 16, 17, which are connected via extending in the sanding pad 5 suction channels 18 with dust outlet openings 20 which are arranged on the sanding pad bottom 12 opposite sanding pad top 19. The grinding machine 1 includes a dust extraction device or is connected via a suction hose to such, so that the dust sucked through the dust extraction openings 16, 17, the suction channels 18 and the dust outlet openings 20 via the grinding machine 1 is discharged.

The sanding sheet 13 has a hole pattern corresponding to the dust extraction openings 16, 17 of the sanding pad underside 12 and consists of suction holes 16a, 17a. The abrasive sheet 13 is fixed so that the suction holes 16a are aligned with the dust suction holes 16 and the suction holes 17a are aligned with the dust suction holes 17. The abrasive sheet 13 also contains one of the central through hole 7 of the sanding pad 5 corresponding central hole 7a.

On the sanding pad bottom 12, in addition to the Staubabsaugöffnungen 16, 17 outside of the central region 6, a plurality of Luftzuströmöffnungen 21 are arranged on the outside in the sanding pad 5 separately from the suction channels 18 extending inflow channels 22 in the attached to the grinding machine 1 state of the sanding pad 5 off the dust extractor of the grinding machine are connected to the environment. Expediently, the inflow channels 22 open out into the environment in the peripheral region of the sanding pad 5. These channel mouths 23 are from the Figures 3 and 5 seen. The inflow channels 22 extend substantially parallel to the sanding pad bottom 12. The air inflow openings 21 are connected in extension of these running branch channels 24 with the inflow channels 22.

The sanding pad 5 has a two-part construction and essentially consists of a sanding pad upper part 25 of relatively rigid material to be fastened to the sanding machine 1 and a sanding pad lower part 26 of elastically deformable plastic material attached to the upper part 25, which abuts when sanding can cling to the workpiece. The inflow channels 22 described run in the lower part and are molded from above into the plastic material of the lower part. The inflow channels 22 are covered by the sanding pad top 25, i. the sanding pad upper part 25 is formed closed at the location of the inflow channels 22. The upper part 25, in contrast, contains the dust outlet openings 20.

The above-mentioned tightening ring section 11 is located on the sanding pad upper part 25th

How out FIG. 7 it can be seen, the abrasive sheet 13 is formed closed at the locations corresponding to the air inlet openings 21 arranged away from the central sanding pad area 6. The air inflow openings 21 thus open at the sanding pad underside 12 and are covered by the sanding sheet 13, ie the inflow channels 22 and the associated air inflow openings 21 terminate, so to speak, inside the hook and loop fastener.

In operation, the dust is sucked through the suction holes 16a, 17a of the abrasive sheet 13 and the dust extraction openings 16, 17 on the sanding pad bottom 12. In this case, the dust particles move transversely to the two Velcro adhesive pads 14, 15 therethrough. In doing so, they partly arrive between the two Velcro pads 14, 15, so that in the course of time between the Velcro pads 14, 15 so-called dust nests can form. The two Velcro pads 14, 15 are relatively "airy" to each other, which favors the entry of dust particles between the Velcro pads 14, 15.

In the present case, the formation of these dust nests is counteracted by the air inflow openings connected to the surroundings. The air inflow openings 21 are arranged in the area of action of the dust extraction openings 16, 17 in such a way that a transverse flow from the air inflow openings 21 to the dust extraction openings 16, 17 is formed during operation on the sanding pad underside 12 between the two Velcro adhesive linings 14, 15. This cross flow is in the Figures 2 and 6 symbolically represented by the arrows. In FIG. 6 these arrows are not drawn across the entire surface of the sanding pad.

Since the inflow channels 22 are in open communication with the environment, ambient air can flow in, so that between the two Velcro adhesive layers 14, 15, said cross flow can be directed towards the Staubabsaugöffnungen 16, 17 and thus the dust particles from entering between prevents the two Velcro pads 14, 15, or already existing dust particles to the Staubabsaugöffnungen 16, 17 returns.

The Staubabsaugöffnungen 16, 17 are arranged on radially extending radius lines, which follow one another in the circumferential direction with at least substantially equal angular intervals. The Luftzuströmöffnungen 21 are arranged in the spaces between the radius lines 27. It is understood that In addition, even more suction and Luftzuströmöffnungen may be present.

Another expedient measure is that the dust extraction openings 16, 17 - apart from possibly additionally existing Staubabsaugöffnungen - evenly distributed on at least one circular line 28, 29 around the sanding pad center and the Luftzuströmöffnungen 21 - again apart from any additionally existing Luftzuströmöffnungen - in the circumferential direction between the Staubabsaugöffnungen 16, 17 are arranged.

In the preferred embodiment, an inner row of dust extraction openings 16 disposed on an inner circular line 28 of smaller radius is an outer row of dust extraction openings 17 located on an outer circular line 29 of larger radius and one on a middle circular line 30 between the smaller inner circle radius 28 and the larger radius of the outer circle 29 lying middle radius arranged series of Luftzuströmöffnungen 21 available. In this case, the Staubabsaugöffnungen 17 of the outer row (circular line 29) and the Staubabsaugöffnungen 16 of the inner row (circular line 28) are arranged in the radial direction in alignment with each other.

The arrangement and distances of the air inflow openings 21 to the Staubabsaugöffnungen 16, 17 should be chosen so that virtually at all Staubabsaugöffnungen 16, 17, a cross-flow occurs.

In this context, it is expedient that between at least two circumferentially successive radius lines 27, on each of which at least one Staubabsaugöffnung 16, 17 is located, at least two in the circumferential direction at a distance arranged to each other air inlet openings 21 are arranged. In this case, the two air inlet openings 21, as in particular FIG. 6 shows, a substantially equal distance to each adjacent radius line 27.

In particular, for aerodynamic reasons, the Luftzuströmöffnungen 21 should have a smaller diameter than the Staubabsaugöffnungen.

As described, the Luftzuströmöffnungen 21 are arranged in the circumferentially successive gaps, which are arranged between the radius lines 27, on each of which at least one Staubabsaugöffnung 16, 17 is arranged. In this connection, an expedient measure is that a common inflow channel 22 is assigned to the air inflow openings 21 arranged in each case in two adjacent interspaces, which begins at one end at its inner end 31 in one of the two intermediate spaces at the at least one air inflow opening 21 from there to the at least one air inlet opening 21 in the other intermediate space and from there to the outside to the mouth 23 extends. Out FIG. 5 shows that the respective common inflow channel 22 has a J-like course and thereby extends radially inward around the at least one suction channel 18 which is disposed on the radial line 27 lying between the two interspaces.

In the embodiment, the Luftzuströmöffnungen 21 in said spaces, as mentioned, arranged in pairs. The inflow channels 22 have a corresponding broadening at the locations of the pairs of air inflow openings 21, so that both air inflow openings 21 are detected (see FIG FIG. 5 ).

In connection with the Staubabsaugöffnungen 16, 17, suction ducts 18 and dust outlet openings 20 is still to be noted that each of the two lying on a radius line 27 Staubabsaugöffnungen 16, 17, a Absaugkanalabschnitt going upwards, wherein the two channel sections by a radially extending channel portion with each other are connected, which leads to the two Staubabsaugöffnungen 16, 17 associated dust outlet opening 20. Said channel sections were designated overall by the reference numeral 18.

Finally, go out FIG. 5 still apparent that each of the inflow channels 22 a leading to the central passage opening 7 of the sanding pad 5 channel section 32 goes off. Since the abrasive sheet 13 is perforated at the location of the central through hole 7, in this way ambient air can reach the underside of the sanding sheet 13 and flow there in the radial direction between the workpiece and the sanding sheet to the Staubabsaugöffnungen 16, 17.

Claims (18)

Sanding plate for a hand-held, motor-driven grinding machine (1), wherein the sanding pad (5) with its central region (6) on the grinding machine (1) can be fastened and executes a rotating and / or orbiting motion in the attached state during operation and wherein the sanding plate (5) has dust extraction openings (16, 17) on its underside (12) which faces the workpiece to be sanded during operation and which has suction channels (18) running in the sanding plate (5) with sanding plates facing the sanding machine (1). Dust exit openings (20) are arranged so that the grinding dust produced during grinding can be removed by means of a machine-side dust extraction device, characterized in that on the sanding pad underside (12) outside the central sanding pad area (6) a plurality of Luftzuströmöffnungen (21) is arranged, which in the sanding plate separately from the suction len (18) extending inflow channels (22) are connected in the mounted on the grinding machine (1) state away from the Staubabsaugeinrichtung with the environment, wherein the Luftzuströmöffnungen (21) in the area of action of Staubabsaugöffnungen (16, 17) are arranged such that in Operation on the sanding pad bottom (12) forms a transverse flow from the Luftzuströmöffnungen (21) to the Staubabsaugöffnungen (16, 17). Sanding pad according to claim 1, characterized in that the Staubabsaugöffnungen (16, 17) at least partially on in the circumferential direction with at least substantially equal angular intervals successive, radially extending radius lines (27) and the Luftzuströmöffnungen (21) at least partially in the spaces between the Radius lines (27) are arranged. Sanding pad according to claim 1 or 2, characterized in that the Staubabsaugöffnungen (16, 17) at least partially evenly distributed on at least one circular line (28, 29) around the sanding pad around and the Luftzuströmöffnungen (21) at least partially in the circumferential direction between the Staubabsaugöffnungen (16, 17) are arranged. Sanding pad according to claim 2 or 3, characterized in that an inner row of Staubabsaugöffnungen (16) arranged on an inner circular line (28) with a smaller radius, an outer row of Staubabsaugöffnungen (17) arranged on an outer circular line (29) with a larger radius and a series of air inflow openings (21) arranged on a central circular line (30) having an average radius lying between the smaller radius of the inner circular line (28) and the larger radius of the outer circular line (29) are provided. Sanding pad according to claim 4, characterized in that the Staubabsaugöffnungen (17) of the outer row and the Staubabsaugöffnungen (16) of the inner row are arranged in the radial direction in alignment with each other. Sanding pad according to one of claims 2 to 5, characterized in that between each two circumferentially successive radius lines (27), on each of which at least one Staubabsaugöffnung (16, 17) is located, at least two circumferentially spaced apart Luftzuströmöffnungen (21) are arranged. Sanding pad according to claim 6, characterized in that the two Luftzuströmöffnungen (21) have a substantially equal distance from the respective adjacent radius line. Sanding pad according to one of claims 1 to 7, characterized in that the Luftzuströmöffnungen (21) have a smaller diameter than the Staubabsaugöffnungen (16, 17). Sanding pad according to one of claims 1 to 8, characterized in that the inflow channels (22) open out into the environment in the peripheral region of the sanding plate (5). Sanding disc according to claim 9, characterized in that it comprises an upper part (25) of rigid material to be fastened to the grinding machine (1) and a lower part (26) made of elastically deformable plastic material attached to the upper part (25), wherein the inflow channels ( 22) in the lower part (26) and are covered by the upper part (25). Sanding pad according to one of claims 2 to 10, characterized in that in each of two circumferentially successive, both sides of a at least one Staubabsaugöffnung (16, 17) having radius line (27) located intermediate air inlet openings (21) associated with a common inflow channel (22) is, which begins at one end in one of the two spaces at the local at least one Luftzuströmöffnung (21), from there to the at least one air inlet opening (21) extends in the other intermediate space and from there to the outside. Sanding pad according to claim 11, characterized in that the respective inflow channel (22) has a J-like course and thereby extends radially inward around the at least one suction channel (18) arranged between the two interspaces. Sanding pad according to one of claims 1 to 12, characterized in that at least one of the inflow channels (22) is connected to a channel section (32) connected to a central passage opening (7) of the sanding disc (5). Abrasive sheet for a sanding pad (5) according to one of claims 1 to 13, wherein the sanding sheet (13) can be detachably fastened to the sanding pad underside (12) by means of a hook-and-loop fastener, characterized in that the sanding sheet (13) has dust extraction openings (16 , 17) of the sanding plate (5) associated with suction holes (16a, 17a), and that the abrasive sheet (13) has closed areas in the region of Luftzuströmöffnungen (21) of the sanding pad (5), so that during operation on the sanding pad bottom (12) forms a cross flow from the air inflow openings (21) to the dust exhaust openings (16, 17) along the closed areas. Abrasive sheet according to claim 14, characterized in that the air inflow openings (21) associated with closed areas are arranged away from a central sanding pad area. Sanding sheet according to claim 14 or 15, characterized in that the sanding sheet (13) is a central one Having through hole (7) of the grinding plate (5) corresponding central hole (7a). An abrasive sheet according to any one of claims 14 to 16, characterized in that the suction holes (16a, 17a) are at least partially distributed evenly around at least one circular line (28, 29) around the abrasive sheet center and the closed regions associated with the air inflow holes (21) at least to Part in the circumferential direction between the suction holes (16a, 17a) are arranged. An abrasive sheet according to any one of claims 14 to 17, characterized in that a part of the suction holes (16a) is disposed on an inner circle (28) of smaller radius and part of the suction holes (17a) on an outer circle (29) of larger radius and that the closed areas associated with the air inflow openings (21) lie between the smaller radius of the inner circle (28) and the larger radius of the outer circle (29).

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