EP0404133B1 - Device for dry grinding of surfaces - Google Patents

Device for dry grinding of surfaces Download PDF

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Publication number
EP0404133B1
EP0404133B1 EP90111701A EP90111701A EP0404133B1 EP 0404133 B1 EP0404133 B1 EP 0404133B1 EP 90111701 A EP90111701 A EP 90111701A EP 90111701 A EP90111701 A EP 90111701A EP 0404133 B1 EP0404133 B1 EP 0404133B1
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EP
European Patent Office
Prior art keywords
grinding
housing
duct
holding
fan
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EP90111701A
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German (de)
French (fr)
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EP0404133A3 (en
EP0404133A2 (en
Inventor
Hans-Peter Barthelt
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Festo SE and Co KG
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Festo SE and Co KG
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Publication of EP0404133A2 publication Critical patent/EP0404133A2/en
Publication of EP0404133A3 publication Critical patent/EP0404133A3/en
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    • BPERFORMING OPERATIONS; TRANSPORTING
    • B24GRINDING; POLISHING
    • B24BMACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
    • B24B55/00Safety devices for grinding or polishing machines; Accessories fitted to grinding or polishing machines for keeping tools or parts of the machine in good working condition
    • B24B55/06Dust extraction equipment on grinding or polishing machines
    • B24B55/10Dust extraction equipment on grinding or polishing machines specially designed for portable grinding machines, e.g. hand-guided
    • B24B55/105Dust extraction equipment on grinding or polishing machines specially designed for portable grinding machines, e.g. hand-guided with oscillating tools

Definitions

  • the invention relates to a grinding device for dry surface grinding with the features of the preamble of claim 1.
  • the generic orbital grinders known from practice contain in a housing a drive device for a flat grinding shoe which is elastically fastened to the housing.
  • a geared eccentric device arranged between the grinding shoe and the drive device, the grinding shoe is set into an orbital movement in which each point performs a circular movement of the same diameter.
  • the radius of this circle is small compared to the overall dimensions of the sanding shoe, which holds the abrasive in the form of sandpaper or sanding lies on its surface facing away from the housing.
  • the orbital sanders are equipped with a suction device that is effective on the outer edge of the sanding pad. It either contains a brush ring surrounding the grinding shoe, a vacuum being created within the brush ring with the aid of a blower, or vacuum located near the edge of the grinding shoe, which are connected to the suction side of the blower via channels contained in the grinding shoe.
  • this area of the sanding pad in which the pad made of sanding dust is located between the abrasive and the processed surface, is ineffective and makes no contribution to material removal.
  • the air used for this purpose can be part of the drive air in the case of a pneumatic drive or part of its cooling air in the case of an electric motor drive, which in most cases is cold enough even after flowing through the motor to achieve a cooling effect. In any case, it is able to blow the sanding dust away from the middle area under the sanding shoe, which does not require excessive static pressures.
  • FIG. 1 shows an orbital sander 1, in the housing 2 of which a drive device in the form of an electric or air pressure motor is arranged, which serves to set an abrasive shoe 3 elastically connected to the housing 2 in an oscillating movement relative to the housing 2 .
  • the housing 2 represents the fixed reference point and should remain as quiet as possible.
  • a motor shaft 4 of the drive device is rotatably mounted in a bearing flange 5 of the housing 2 by means of a radial groove ball bearing 6 sealed on both sides about an axis of rotation 7 which extends at right angles to a plane defined by the grinding shoe 3.
  • the oscillating movement of the grinding shoe 3 produces an eccentric 8, which is fixed in a rotationally fixed manner on the end of the motor shaft 4 protruding from the deep groove ball bearing 6 and has a cylindrical outer peripheral surface whose axis of symmetry 9 is radially offset with respect to the axis of rotation 7 of the motor shaft 4.
  • On the eccentric 8 is another radial deep groove ball bearing 11, which is pushed onto a shoulder 12 of the eccentric 8 until it rests.
  • the axis of symmetry 9 thereby forms the axis of rotation of the eccentric 8 in the grinding shoe 3, which is parallel to the axis of rotation 7.
  • the outer bearing ring of the deep groove ball bearing 11 is in a bearing seat 13 which is located in a dome-like attachment 14 of the grinding shoe 3.
  • the dome-like attachment is an integral part of a rigid plate-shaped upper part 10 and bulges towards the underside of the housing 2. It is located approximately in the middle above the grinding shoe 3.
  • On the flat underside of the plate 10 there is an elastic one Glued on the support plate 15, which forms a flat surface 16 that extends at right angles to the axis of rotation 7, on which, when using the orbital sander 1, the non-illustrated sanding paper or abrasive fleece, which form the actual abrasive, is held.
  • the fastening devices for holding the sanding paper or sanding fleece are omitted for the sake of clarity.
  • the eccentric 8 is axially secured on the output shaft by means of a countersunk screw 17 which is screwed into a coaxial threaded bore 19 of the output shaft 4 with the interposition of a washer 18.
  • the washer 18 forms the contact surface for the bottom end face of the eccentric 8 or the balancing weight.
  • a suction device 25 which has a radial fan 27 arranged in a chamber 26 and seated in a rotationally fixed manner on the motor shaft 4.
  • the radial fan 27 forms, together with the chamber 26, a blower, the pressure side of which is connected via channels (not shown) to a connection 28 protruding from the housing 2 for a filter bag (not shown).
  • the suction side of the blower formed by the radial fan 27 and the chamber 26 is connected via an elastic hose 29 to a channel system 31 inside the grinding shoe 3.
  • the elastic hose 29 sits at one end on an unrecognizable socket of the housing 2 and on a likewise invisible socket on the top of the plate 10 and is secured by means of hose clips 32, 33.
  • the channel system 31 is located between the plate 10 and the underside 16 and connects an opening 34 in the plate 10 to the hose 29 with the channel system 31.
  • the channel system 31 consists essentially of two branches 35 and 36, which are parallel to the two longer sides run and open into a total of six through holes 37 which connect the channel system 31 to the underside 16.
  • a flat rounded groove 38 leads in the shortest possible way directly to an adjacent side edge 39 or 41 of the grinding shoe 3. In this way, not only is the grinding dust located below the underside 16 near the holes 37, but also that Dust located next to the grinding shoe 3 is sucked in and conveyed by the radial fan 27 to the filter bag connected to the connecting piece 28.
  • the opening 44 is surrounded by a nozzle on which a further elastic hose 45 is attached.
  • the hose 45 connects the duct 43 to the pressure side of a further blower 46, which contains a radial fan 47, which is also non-rotatably seated on the motor shaft 4.
  • the radial fan 47 is separated from the radial fan 27 in terms of flow and, moreover, serves to convey cooling air through the motor of the orbital sander 1.
  • the air emerging on the pressure side of the blower 46 is partly blown outside and partly reaches the underside 16 via the hose or channel 45, which is shown in broken lines. To illustrate these relationships, there is an opening next to the radial fan 47 48 of the channel 45 schematically illustrated.
  • the blow-out opening 42 thus effectively prevents the formation of a cushion of grinding dust in a central area between the suction openings 37.
  • the central area which is located between the two rows of suction openings 37 lying next to one another in parallel, is in this way inevitably kept free of grinding dust and can make its contribution to material removal, which would not be possible if sanding dust accumulates at this point and lifts the abrasive off the surface to be machined.
  • the abrasive paper or abrasive fleece has at least one opening aligned with the opening 42 so that the blown-in air can get between the abrasive and the surface to be processed.
  • the constant escape of air from the opening 42 is undesirable, for example when heavily curved surfaces are machined, or the orbital sander is inclined on the surface to be machined for the purpose of increased material removal.
  • the cushion of grinding dust occurring between the two rows of suction openings can also be effectively removed.
  • the channel 43 is not extended to the pressure side of the blower 46, but opens into a channel 49 which opens on a side surface of the grinding shoe 3.
  • the suction openings 37 located at the edge of the grinding shoe 3 are able to generate an air flow in the central region of the underside 16, which is directed towards the suction openings 37.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Grinding-Machine Dressing And Accessory Apparatuses (AREA)
  • Finish Polishing, Edge Sharpening, And Grinding By Specific Grinding Devices (AREA)

Description

Die Erfindung betrifft eine Schleifvorrichtung zum trockenen Flächenschleifen mit den Merkmalen des Oberbegriffs des Anspruches 1.The invention relates to a grinding device for dry surface grinding with the features of the preamble of claim 1.

Die aus der Praxis bekannten gattungsgemäßen Schwingschleifer (siehe z.B. US-A-3 866 304) enthalten in einem Gehäuse eine Antriebseinrichtung für einen an dem Gehäuse elastisch befestigten flächenförmigen Schleifschuh. Durch eine getriebliche, zwischen dem Schleifschuh und der Antriebseinrichtung angeordnete Exzentereinrichtung wird der Schleifschuh in eine Orbitalbewegung versetzt, bei der jeder Punkt eine Kreisbewegung gleichen Durchmessers vollführt. Der Radius dieses Kreises ist klein gegenüber den Gesamtabmessungen des Schleifschuhs, der auf seiner vom Gehäuse weggerichteten Fläche das Schleifmittel in Gestalt von Schleifpapier oder Schleifylies haltert.The generic orbital grinders known from practice (see, for example, US Pat. No. 3,866,304) contain in a housing a drive device for a flat grinding shoe which is elastically fastened to the housing. By means of a geared eccentric device arranged between the grinding shoe and the drive device, the grinding shoe is set into an orbital movement in which each point performs a circular movement of the same diameter. The radius of this circle is small compared to the overall dimensions of the sanding shoe, which holds the abrasive in the form of sandpaper or sanding lies on its surface facing away from the housing.

Damit der beim Schleifen entstehende Schleifstaub möglichst wenig die Umgebung verunreinigt, sind die Schwingschleifer mit einer Absaugvorrichtung versehen, die am äußeren Rand des Schleifschuhs wirksam ist. Sie enthält entweder einen den Schleifschuh umgebenden Bürstenkranz, wobei innerhalb des Bürstenkranzes mit Hilfe eines Gebläses ein den Schleifstaub absaugender Unterdruck entsteht oder in der Nähe des Randes des Schleifschuhs befindliche Öffnungen, die über im Schleifschuh enthaltene Kanäle mit der Saugseite des Gebläses verbunden sind.So that the sanding dust generated during sanding contaminates the surroundings as little as possible, the orbital sanders are equipped with a suction device that is effective on the outer edge of the sanding pad. It either contains a brush ring surrounding the grinding shoe, a vacuum being created within the brush ring with the aid of a blower, or vacuum located near the edge of the grinding shoe, which are connected to the suction side of the blower via channels contained in the grinding shoe.

Keine dieser Absaugvorrichtungen kann es allerdings verhindern, daß zwischen dem Schleifschuh und dem zu bearbeitenden Werkstück im mittleren Bereich des Schleifschuhs ein Polster aus Schleifstaub entsteht, durch das das Schleifmittel von dem zu bearbeitenden Werkstück abgehoben wird. Dieses Polster aus Schleifstaub ist, bezogen auf den Schleifschuh, im wesentlichen stationär , denn selbst wenn der Schwingschleifer auf der Werkstückoberfläche entlanggeschoben wird, wird zwar auf der Seite des Polsters, die entgegen der Bewegungsrichtung liegt, Schleifstaub abgesaugt. Dafür entsteht aber auf der in Bewegungsrichtung liegenden Seite ständig neuer, das Polster aufrecht erhaltender Schleifstaub.However, none of these suction devices can prevent a cushion of grinding dust from being formed between the grinding shoe and the workpiece to be machined in the central region of the grinding shoe, through which the abrasive is lifted off the workpiece to be machined. This pad made of sanding dust is essentially stationary with respect to the sanding pad, because even if the orbital sander is pushed along the workpiece surface, sanding dust is sucked off on the side of the pad that is opposite to the direction of movement. But on the side lying in the direction of movement, new grinding dust is constantly being created.

Unabhängig von der Bewegung des Schwingschleifers ist deshalb dieser Bereich des Schleifschuhs, in dem sich zwischen dem Schleifmittel und der bearbeiteten Oberfläche das Polster aus Schleifstaub befindet, wirkungslos und liefert keinen Beitrag zum Materialabtrag. Bei geringer translatorischer Bewegung des Schwingschleifers wird nur das Polster aus Schleifstaub ständig durchgearbeitet und erwärmt, was besonders nachteilig ist, wenn es sich um Schleifstaub aus Lack handelt, der mit zunehmender Temperatur beginnt, klebrig zu werden. Es besteht die Gefahr, daß Schleifstaubpartikel zusammenbacken und sich auf dem Schleifmittel festsetzen. Die so entstehende Erhöhung reißt Spuren in die bearbeitete Lackfläche.Regardless of the movement of the orbital sander, this area of the sanding pad, in which the pad made of sanding dust is located between the abrasive and the processed surface, is ineffective and makes no contribution to material removal. With a small translatory movement of the orbital sander, only the pad made of sanding dust is continuously worked through and heated, which is particularly disadvantageous when it comes to sanding dust made of lacquer, which begins to become sticky with increasing temperature. There is a risk that grinding dust particles will cake and stick to the abrasive. The resulting increase tears marks in the processed paint surface.

Ausgehend hiervon ist es Aufgabe der Erfindung, eine Schleifvorrichtung zu schaffen, bei der beim Flächenschleifen die Entstehung eines derartigen Polsters aus Schleifstaub wirksam verhindert ist.Proceeding from this, it is an object of the invention to provide a grinding device in which the formation of such a cushion of grinding dust is effectively prevented during surface grinding.

Diese Aufgabe wird erfindungsgemäß durch die Schleifvorrichtung mit den Merkmalen des Anspruches 1 gelöst.This object is achieved by the grinding device with the features of claim 1.

Infolge der im mittleren Bereich des Schleifschuhs befindlichen Öffnung, die nicht mit der Absaugvorrichtung verbunden ist, kann sich dort kein Unterdruck ausbilden. Vielmehr ist die am Rand wirksame Absaugvorrichtung in der Lage, aus diesem mittleren Bereich den Schleifstaub abzusaugen, weil über diese, im mittleren Bereich befindliche Öffnung Luft nachströmen kann.As a result of the opening in the middle area of the grinding shoe, which is not connected to the suction device, no negative pressure can develop there. Rather, the suction device effective at the edge is able to extract the grinding dust from this central area, because air can flow in through this opening located in the central area.

Der Abtransport des Schleifstaubs aus dem mittleren Bereich unter dem Schleifschuh wird besonders begünstigt, wenn diese Öffnung, die gleichsam als Auslaßöffnung wirksam ist, über den Kanal mit der Druckseite eines Gebläses verbunden ist. Gleichzeitig wird hierdurch vermehrt Kühlluft in den mittleren Bereich unter dem Schleifschuh gebracht, um das Schleifmittel dort zu kühlen und die Gefahr der Plastifizierung von Lackoberflächen zu beseitigen.The removal of the grinding dust from the central area under the grinding shoe is particularly favored if this opening, which acts as an outlet opening, is connected via the duct to the pressure side of a blower. At the same time, this increases the amount of cooling air in the middle area under the sanding pad in order to cool the abrasive there and to eliminate the risk of plasticizing paint surfaces.

Die hierfür verwendete Luft kann im Falle eines pneumatischen Antriebs ein Teil der Antriebsluft sein oder im Falle eines elektromotorischen Antriebs ein Teil von dessen Kühlluft, die in den meisten Fällen auch nach dem Durchströmen des Motors kalt genug ist, um eine Kühlwirkung zustandezubringen. Jedenfalls ist sie in der Lage, den Schleifstaub aus dem mittleren Bereich unter dem Schleifschuh wegzublasen, wozu keine allzu großen statischen Drücke erforderlich sind.The air used for this purpose can be part of the drive air in the case of a pneumatic drive or part of its cooling air in the case of an electric motor drive, which in most cases is cold enough even after flowing through the motor to achieve a cooling effect. In any case, it is able to blow the sanding dust away from the middle area under the sanding shoe, which does not require excessive static pressures.

Wenn es beim Schleifen auf gewölbten Flächen oder mit schräg gestelltem Schwingschleifer als unangenehm empfunden wird, daß die eingeblasene Kühlluft den Schleifstaub aufwirbelt, ist es auch ausreichend, diese Öffnung über den Kanal mit dem Rand des Schleifschuhs zu verbinden.If it is uncomfortable when grinding on curved surfaces or with an inclined orbital sander that the injected cooling air whirls up the grinding dust, it is also sufficient to connect this opening via the channel to the edge of the grinding shoe.

Bei besonders großen Flächen kann es zweckmäßig sein, in der Mitte des Schleifschuhs mehrere Auslaßöffnungen vorzusehen, von denen einige mit der Druckseite eines Gebläses verbunden sind, während die anderen über einen Kanal unmittelbar zum Rand des Schleifschuhs hin belüftet sind.In the case of particularly large areas, it may be expedient to provide a plurality of outlet openings in the center of the grinding shoe, some of which are connected to the pressure side of a blower, while the others are ventilated via a channel directly to the edge of the grinding shoe.

Im übrigen sind Weiterbildungen der Erfindung Gegenstand von Unteransprüchen.For the rest, further developments of the invention are the subject of dependent claims.

In der Zeichnung sind Ausführungsbeispiele des Gegenstandes der Erfindung dargestellt. Es zeigen:

Fig. 1
den Schwingschleifer gemäß der Erfindung in einer Seitenansicht und teilweise aufgebrochen,
Fig. 2
eine Draufsicht auf den Schleifschuh des Schwingschleifers nach Fig. 1 mit gestrichelt angedeuteten Kanälen in einer Ansicht von unten und
Fig. 3
einen Schleifschuh der Vorrichtung nach Fig. 1 mit einer anderen Führung des Kanals für die Auslaßöffnung, ebenfalls in einer Ansicht von unten.
Exemplary embodiments of the subject matter of the invention are shown in the drawing. Show it:
Fig. 1
the orbital sander according to the invention in a side view and partially broken,
Fig. 2
a plan view of the grinding shoe of the orbital sander of FIG. 1 with channels indicated by dashed lines in a view from below and
Fig. 3
1 with another guide of the channel for the outlet opening, also in a view from below.

In Fig. 1 ist ein Schwingschleifer 1 veranschaulicht, in dessen Gehäuse 2 eine Antriebseinrichtung in Gestalt eines Elektro- oder Luftdruckmotors angeordnet ist, der dazu dient, einen mit dem Gehäuse 2 elastisch verbundenen Schleifschuh 3 relativ zu dem Gehäuse 2 in eine oszillierende Bewegung zu versetzen. Das Gehäuse 2 stellt dabei den raumfesten Bezugspunkt dar und soll möglichst in Ruhe bleiben. Zum Erzeugen der Relativbewegung ist hierzu eine Motorwelle 4 der Antriebseinrichtung in einem Lagerflansch 5 des Gehäuses 2 mittels eines beidseits abgedichteten Radialrillenkugellagers 6 um eine Drehachse 7 drehbar gelagert, die rechtwinklig zu einer durch den Schleifschuh 3 definierten Ebene verläuft. Die oszillierende Bewegung des Schleifschuhs 3 erzeugt ein Exzenter 8, der drehfest auf dem aus dem Rillenkugellager 6 herausragenden Ende der Motorwelle 4 befestigt ist und eine zylindrische Außenumfangsfläche aufweist, deren Symmetrieachse 9 bezüglich der Drehachse 7 der Motorwelle 4 radial versetzt ist. Auf dem Exzenter 8 steckt ein weiteres Radialrillenkugellager 11, das bis zur Anlage an einer Schulter 12 des Exzenters 8 aufgeschoben ist. Die Symmetrieachse 9 bildet hierdurch die Drehachse des Exzenters 8 in dem Schleifschuh 3, die zu der Drehachse 7 parallel ist.1 shows an orbital sander 1, in the housing 2 of which a drive device in the form of an electric or air pressure motor is arranged, which serves to set an abrasive shoe 3 elastically connected to the housing 2 in an oscillating movement relative to the housing 2 . The housing 2 represents the fixed reference point and should remain as quiet as possible. To generate the relative movement, a motor shaft 4 of the drive device is rotatably mounted in a bearing flange 5 of the housing 2 by means of a radial groove ball bearing 6 sealed on both sides about an axis of rotation 7 which extends at right angles to a plane defined by the grinding shoe 3. The oscillating movement of the grinding shoe 3 produces an eccentric 8, which is fixed in a rotationally fixed manner on the end of the motor shaft 4 protruding from the deep groove ball bearing 6 and has a cylindrical outer peripheral surface whose axis of symmetry 9 is radially offset with respect to the axis of rotation 7 of the motor shaft 4. On the eccentric 8 is another radial deep groove ball bearing 11, which is pushed onto a shoulder 12 of the eccentric 8 until it rests. The axis of symmetry 9 thereby forms the axis of rotation of the eccentric 8 in the grinding shoe 3, which is parallel to the axis of rotation 7.

Der äußere Lagerring des Rillenkugellagers 11 steckt in einem Lagersitz 13, der sich in einem domartigen Aufsatz 14 des Schleifschuhs 3 befindet. Der domartige Aufsatz ist einstückiger Bestandteil eines steifen plattenförmigen Oberteils 10 und wölbt sich der Unterseite des Gehäuses 2 entgegen. Er befindet sich etwa mittig über dem Schleifschuh 3. Auf der planen Unterseite der Platte 10 ist eine elastische Auflageplatte 15 aufgeklebt, die eine ebene und zu der Drehachse 7 rechtwinklig verlaufende Fläche 16 bildet, auf der bei Gebrauch des Schwingschleifers 1 das nicht veranschaulichte Schleifpapier bzw. Schleifvlies, die das eigentliche Schleifmittel bilden, gehaltert ist. Die Befestigungseinrichtungen zum Halten des Schleifpapiers bzw. Schleifvlies sind der Übersichtlichkeit halber weggelassen.The outer bearing ring of the deep groove ball bearing 11 is in a bearing seat 13 which is located in a dome-like attachment 14 of the grinding shoe 3. The dome-like attachment is an integral part of a rigid plate-shaped upper part 10 and bulges towards the underside of the housing 2. It is located approximately in the middle above the grinding shoe 3. On the flat underside of the plate 10 there is an elastic one Glued on the support plate 15, which forms a flat surface 16 that extends at right angles to the axis of rotation 7, on which, when using the orbital sander 1, the non-illustrated sanding paper or abrasive fleece, which form the actual abrasive, is held. The fastening devices for holding the sanding paper or sanding fleece are omitted for the sake of clarity.

Die axiale Sicherung des Exzenters 8 auf der Ausgangswelle erfolgt mittels einer Senkschraube 17, die unter Zwischenlage einer Beilagescheibe 18 in eine koaxiale Gewindebohrung 19 der Ausgangswelle 4 eingeschraubt ist. Die Beilagscheibe 18 bildet dabei die Anlagefläche für die unten liegende Stirnseite des Exzenters 8 bzw. das Auswuchtgewicht.The eccentric 8 is axially secured on the output shaft by means of a countersunk screw 17 which is screwed into a coaxial threaded bore 19 of the output shaft 4 with the interposition of a washer 18. The washer 18 forms the contact surface for the bottom end face of the eccentric 8 or the balancing weight.

Um beim Ingangsetzen des Exzenters 8 ein Umlaufen des Schleifschuhs 3 um die Drehachse 7 zu verhindern und um die gewünschte Orbitalbewegung zu erzwingen, befinden sich in der Nähe der vier Ecken des Schleifschuhs 3 längliche elastische Glieder oder Füße, von denen lediglich der elastische Fuß 21 im aufgebrochenen Teil des Gehäuses 2 erkennbar ist. Diese elastischen Füße 21 stecken, wie der elastische Fuß 21 stellvertretend zeigt, mit ihren Endabschnitten in zylinderförmigen Näpfen 22 und 23, die an der Platte 10 bzw. dem Gehäuse 2 einander gegenüberliegend angeformt sind. Auf diese Weise verlaufen die in den Näpfen 22, 23 befindlichen Abschnitte des elastischen Fußes 21 parallel zu der Drehachse 9 bzw. der Drehachse 7.In order to prevent the grinding shoe 3 from rotating around the axis of rotation 7 when the eccentric 8 is started up and to force the desired orbital movement, there are elongated elastic members or feet near the four corners of the grinding shoe 3, of which only the elastic foot 21 in broken part of the housing 2 can be seen. These elastic feet 21, as representative of the elastic foot 21, show, with their end sections in cylindrical cups 22 and 23, which are formed on the plate 10 and the housing 2 opposite one another. In this way, the sections of the elastic foot 21 located in the cups 22, 23 run parallel to the axis of rotation 9 or the axis of rotation 7.

Durch Ingangsetzen des Exzenters 8, d.h. dadurch, daß er, angetrieben von der Motorwelle 4 um die raumfeste Drehachse 7 umläuft und sich hierbei gleichzeitig in dem Rillenkugellager 11 um seine eigene Drehachse 9 dreht, vollführen sämtliche Punkte des Schleifschuhs 3 Kreisbewegungen mit einem Radius, der dem Abstand der beiden Drehachsen 7 und 9 voneinander entspricht. Dieser Abstand liegt in der Praxis üblicherweise zwischen 2 und 5 mm und ist damit klein gegenüber der planen rechteckigen Unterseite 16 der Auflageplatte 15.By starting the eccentric 8, i.e. characterized in that it rotates, driven by the motor shaft 4 about the fixed axis of rotation 7 and at the same time rotates in the deep groove ball bearing 11 about its own axis of rotation 9, all points of the grinding shoe 3 perform circular movements with a radius that corresponds to the distance between the two axes of rotation 7 and 9 corresponds to each other. In practice, this distance is usually between 2 and 5 mm and is therefore small compared to the flat rectangular underside 16 of the support plate 15.

Um den beim Arbeiten mit dem Schwingschleifer 1 auftretenden Schleifstaub zu beseitigen, ist eine Absaugeinrichtung 25 vorgesehen, die einen in einer Kammer 26 angeordneten und drehfest auf der Motorwelle 4 sitzenden Radiallüfter 27 aufweist. Der Radiallüfter 27 bildet zusammen mit der Kammer 26 ein Gebläse, dessen Druckseite über nicht veranschaulichte Kanäle mit einem aus dem Gehäuse 2 vorstehenden Anschluß 28 für einen nicht gezeigten Filtersack verbunden ist. Die Saugseite des von dem Radiallüfter 27 und der Kammer 26 gebildeten Gebläses steht über einen elastischen Schlauch 29 mit einer Kanalsystem 31 im Inneren des Schleifschuhs 3 in Verbindung. Der elastische Schlauch 29 sitzt hierzu einenends auf einem nicht erkennbaren Stutzen des Gehäuses 2 sowie auf einem ebenfalls nicht sichtbaren Stutzen an der Oberseite der Platte 10 und ist mittels Schlauchbindern 32, 33 gesichert.In order to eliminate the grinding dust occurring when working with the orbital sander 1, a suction device 25 is provided which has a radial fan 27 arranged in a chamber 26 and seated in a rotationally fixed manner on the motor shaft 4. The radial fan 27 forms, together with the chamber 26, a blower, the pressure side of which is connected via channels (not shown) to a connection 28 protruding from the housing 2 for a filter bag (not shown). The suction side of the blower formed by the radial fan 27 and the chamber 26 is connected via an elastic hose 29 to a channel system 31 inside the grinding shoe 3. For this purpose, the elastic hose 29 sits at one end on an unrecognizable socket of the housing 2 and on a likewise invisible socket on the top of the plate 10 and is secured by means of hose clips 32, 33.

Das Kanalsystem 31 befindet sich zwischen der Platte 10 und der Unterseite 16 und verbindet eine in der Platte 10 zu dem Schlauch 29 führende Öffnung 34 mit dem Kanalsystem 31. Das Kanalsystem 31 besteht im wesentlichen aus zwei Ästen 35 und 36, die parallel zu den beiden längeren Seiten verlaufen und in die insgesamt sechs Durchgangsbohrungen 37 einmünden, die das Kanalsystem 31 mit der Unterseite 16 verbinden.The channel system 31 is located between the plate 10 and the underside 16 and connects an opening 34 in the plate 10 to the hose 29 with the channel system 31. The channel system 31 consists essentially of two branches 35 and 36, which are parallel to the two longer sides run and open into a total of six through holes 37 which connect the channel system 31 to the underside 16.

Von jeder der Durchgangsbohrungen 37 führt eine flache ausgerundete Nut 38 auf kürzestem Wege unmittelbar zu einer benachbarten Seitenkante 39 bzw. 41 des Schleifschuhs 3. Auf diese Weise wird nicht nur der unterhalb der Unterseite 16 in der Nähe der Bohrungen 37 befindliche Schleifstaub, sondern auch der neben dem Schleifschuh 3 befindliche Staub eingesaugt und von dem Radiallüfter 27 zu dem an dem Anschlußstutzen 28 angeschlossenen Filtersack gefördert.From each of the through holes 37, a flat rounded groove 38 leads in the shortest possible way directly to an adjacent side edge 39 or 41 of the grinding shoe 3. In this way, not only is the grinding dust located below the underside 16 near the holes 37, but also that Dust located next to the grinding shoe 3 is sucked in and conveyed by the radial fan 27 to the filter bag connected to the connecting piece 28.

Neben diesen Absaugöffnungen bildenden Durchgangsbohrungen 37 befindet sich mittig in dem Schleifschuh 3 noch eine weitere Durchgangsbohrung 42, die jedoch mit dem Kanalsystem 31 nicht in Verbindung steht. Ihr ist vielmehr ein eigener Kanal 43 in dem Schleifschuh 3 zugeordnet, der die Öffnung 42 mit einer Bohrung 44 in der Platte 10 verbindet.In addition to these through-holes 37 forming suction openings, there is a further through-hole 42 in the center of the grinding shoe 3, which, however, is not connected to the channel system 31. Rather, it is assigned its own channel 43 in the grinding shoe 3, which connects the opening 42 to a bore 44 in the plate 10.

Auf der Oberseite der Platte 10 ist die Öffnung 44 von einem Stutzen umgeben, auf den ein weiterer elastischer Schlauch 45 aufgesteckt ist. Der Schlauch 45 verbindet den Kanal 43 mit der Druckseite eines weiteren Gebläses 46, das einen ebenfalls drehfest auf der Motorwelle 4 sitzenden Radiallüfter 47 enthält. Der Radiallüfter 47 ist strömungsmäßig von dem Radiallüfter 27 getrennt und dient im übrigen dazu, Kühlluft durch den Motor des Schwingschleifers 1 hindurchzufördern. Die an der Druckseite des Gebläses 46 austretende Luft wird zum Teil ins Freie abgeblasen und gelangt zu einem Teil über den Schlauch oder Kanal 45, der gestrichelt eingezeichnet ist, unter die Unterseite 16. Um diese Zusammenhänge zu veranschaulichen, ist neben dem Radiallüfter 47 eine Mündung 48 des Kanals 45 schematisch veranschaulicht.On the top of the plate 10, the opening 44 is surrounded by a nozzle on which a further elastic hose 45 is attached. The hose 45 connects the duct 43 to the pressure side of a further blower 46, which contains a radial fan 47, which is also non-rotatably seated on the motor shaft 4. The radial fan 47 is separated from the radial fan 27 in terms of flow and, moreover, serves to convey cooling air through the motor of the orbital sander 1. The air emerging on the pressure side of the blower 46 is partly blown outside and partly reaches the underside 16 via the hose or channel 45, which is shown in broken lines. To illustrate these relationships, there is an opening next to the radial fan 47 48 of the channel 45 schematically illustrated.

Beim Betrieb des solchermaßen gestalteten Schwingschleifers 1 wird ständig eine gewisse Menge Luft mit einem geringen Druck von dem Gebläse 46 durch den Kanal 45 sowie den Kanal 43 aus der Öffnung 42 in der Unterseite 16 ausgeblasen. Die aus der Öffnung 42 austretende Luft bläst den sich in der Umgebung befindlichen Schleifstaub in Richtung zu den Absaugöffnungen 37, von wo er, ehe er unter der Unterseite 16 hervortreten kann, über das Kanalsystem 31, den Schlauch 29 und das Gebläse 26, 27 zum Filtersack hin abgesaugt wird.During the operation of the orbital sander 1 designed in this way, a certain amount of air is continuously blown out of the opening 46 in the underside 16 by the blower 46 through the duct 45 and the duct 43. The air emerging from the opening 42 blows the grinding dust in the vicinity towards the suction openings 37, from where it can, before it can emerge from underneath 16, via the channel system 31, the hose 29 and the blower 26, 27 to Filter bag is sucked out.

Die Ausblasöffnung 42 verhindert auf diese Weise wirksam die Bildung eines Polsters aus Schleifstaub in einem mittleren Bereich zwischen den Absaugöffnungen 37. Der mittlere Bereich, der sich zwischen den beiden parallel nebeneinander liegenden Reihen von Absaugöffnungen 37 befindet, wird auf diese Weise zwangsläufig von Schleifstaub freigehalten und kann seinen Beitrag zum Materialabtrag liefern, was nicht möglich wäre, wenn sich an dieser Stelle Schleifstaub ansammelt, der das Schleifmittel von der zu bearbeitenden Oberfläche abhebt.The blow-out opening 42 thus effectively prevents the formation of a cushion of grinding dust in a central area between the suction openings 37. The central area, which is located between the two rows of suction openings 37 lying next to one another in parallel, is in this way inevitably kept free of grinding dust and can make its contribution to material removal, which would not be possible if sanding dust accumulates at this point and lifts the abrasive off the surface to be machined.

Es versteht sich, daß das Schleifpapier oder Schleifvlies zumindest eine mit der Öffnung 42 fluchtende Öffnung aufweist, damit die eingeblasene Luft zwischen das Schleifmittel und die zu bearbeitende Oberfläche gelangen kann.It is understood that the abrasive paper or abrasive fleece has at least one opening aligned with the opening 42 so that the blown-in air can get between the abrasive and the surface to be processed.

Im übrigen ist es auch möglich, anstelle nur einer Öffnung 42 die im gezeigten Ausführungsbeispiel im Schnittpunkt der Diagonalen der rechteckigen Unterseite 24 angeordnet ist, auch mehrere Ausblasöffnungen vorzusehen, die bevorzugt längs einer Geraden angeordnet sind, die parallel zu den beiden längeren Kanten 39, 41 verläuft.Otherwise, it is also possible, instead of only one opening 42, which in the exemplary embodiment shown is arranged at the intersection of the diagonals of the rectangular underside 24, to provide a plurality of blow-out openings, which are preferably arranged along a straight line which is parallel to the two longer edges 39, 41 runs.

Unter bestimmten Umständen ist der ständige Luftaustritt aus der Öffnung 42 unerwünscht, beispielsweise wenn stark gekrümmte Oberflächen bearbeitet werden, oder der Schwingschleifer auf der zu bearbeitenden Oberfläche zwecks verstärktem Materialabtrag schräg gestellt wird. In diesem Falle läßt sich ebenfalls das zwischen den beiden Reihen von Absaugöffnungen auftretende Polster aus Schleifstaub wirksam beseitigen. In diesem Falle wird, wie Fig. 3 zeigt, der Kanal 43 nicht zu der Druckseite des Gebläses 46 verlängert, sondern mündet in einen Kanal 49, der an einer Seitenfläche des Schleifschuhs 3 mündet. Die am Rand des Schleifschuhs 3 befindlichen Absaugöffnungen 37 sind hierdurch in der Lage, auch in dem mittleren Bereich der Unterseite 16 eine Luftströmung zu erzeugen, die auf die Ansaugöffnungen 37 gerichtet ist.Under certain circumstances, the constant escape of air from the opening 42 is undesirable, for example when heavily curved surfaces are machined, or the orbital sander is inclined on the surface to be machined for the purpose of increased material removal. In this case, the cushion of grinding dust occurring between the two rows of suction openings can also be effectively removed. In this case, as shown in FIG. 3, the channel 43 is not extended to the pressure side of the blower 46, but opens into a channel 49 which opens on a side surface of the grinding shoe 3. As a result, the suction openings 37 located at the edge of the grinding shoe 3 are able to generate an air flow in the central region of the underside 16, which is directed towards the suction openings 37.

Claims (8)

  1. Grinding device for dry surface grinding, with a housing (2) and a drive means arranged in the housing (2), which moves a grinding material holding device (3) for grinding which device is movably supported on the housing (2) and provided with a surface (16) averted from said housing (2) for holding grinding material, and with an extractor means (25), which in said surface (16) or adjacent to said surface (16) of said grinding material holding device (3) is provided with ventilation openings (37, 38) for the extraction of dust produced during the grinding operation, which are connected to the suction side of a fan (26, 27) via ducts (31, 29), characterised in that in said surface (16), at least one opening (42) independent of said ventilation openings (37) is provided, which feeds into a duct (43), which is not connected to the suction side of said fan (26, 27) of said extractor means (25).
  2. Grinding device according to Claim 1, characterised in that the duct (43) is optionally connected via a further duct (45) for flow to the pressure side of a fan (46).
  3. Grinding device according to Claim 2, characterised in that the additional fan (46) is the fan for cold air to the drive means.
  4. Grinding device according to Claim 1, characterised in that the duct (43, 49) feeds into the side of the grinding material holding device (3), which is not the surface (16) averted from the housing (2) for holding the grinding material.
  5. Grinding device according to Claim 1, characterised in that several openings (42) independent of the ventilation openings (37) are provided.
  6. Grinding device according to Claim 1, characterised in that said at least one additional opening (42), which is independent of the ventilation openings (37), is located in a central area of the surface (16) for holding the grinding material averted from the housing (2).
  7. Grinding device according to Claim 5, characterised in that said several openings (42) independent of the ventilation openings (37) are located on a central line of the surface (16) for holding the grinding material averted from the housing (2).
  8. Grinding device according to Claim 1, characterised in that the duct (43) is vented to the atmosphere.
EP90111701A 1989-06-20 1990-06-20 Device for dry grinding of surfaces Expired - Lifetime EP0404133B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE3920021 1989-06-20
DE3920021A DE3920021C1 (en) 1989-06-20 1989-06-20

Publications (3)

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EP0404133A2 EP0404133A2 (en) 1990-12-27
EP0404133A3 EP0404133A3 (en) 1991-05-02
EP0404133B1 true EP0404133B1 (en) 1994-04-13

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EP90111701A Expired - Lifetime EP0404133B1 (en) 1989-06-20 1990-06-20 Device for dry grinding of surfaces

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EP (1) EP0404133B1 (en)
DE (2) DE3920021C1 (en)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1186379A2 (en) 2000-09-07 2002-03-13 Tholes srl Device for surface grinding and sanding
US7081046B2 (en) 2003-12-03 2006-07-25 Watson Adam Dewain Sanding machine supporting removable side extensions
US7112127B2 (en) 2003-12-03 2006-09-26 Watson Adam Dewain Joint compound sander

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5833524A (en) * 1994-08-22 1998-11-10 Ryobi Limited Dust collection system for a power tool
US6039639A (en) * 1997-02-27 2000-03-21 Robert Bosch Gmbh Motor driven hand tool with improved elastic supporting members connecting an oscillating work tool carrier with the tool housing
DE19941620A1 (en) * 1999-09-01 2001-03-08 Bosch Gmbh Robert Hand tool
ES2199013B1 (en) * 2001-03-13 2005-05-16 Carlos A. Martinez Rodilla PROCEDURE FOR THE TREATMENT OF WOOD, LINOLIUM CORK AND CONCRETE.

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3866304A (en) * 1972-08-21 1975-02-18 Alma A Hutchins Method of piercing air suction holes in abrasive sheet material
US3906682A (en) * 1974-08-15 1975-09-23 Melvin Glasser Sander with dust prevention means
JPH0775821B2 (en) * 1985-11-15 1995-08-16 ファイン―フェルバルツング ゲゼルシャフト ミット ベシュレンクテル ハフツング Portable grinder

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1186379A2 (en) 2000-09-07 2002-03-13 Tholes srl Device for surface grinding and sanding
US7081046B2 (en) 2003-12-03 2006-07-25 Watson Adam Dewain Sanding machine supporting removable side extensions
US7112127B2 (en) 2003-12-03 2006-09-26 Watson Adam Dewain Joint compound sander

Also Published As

Publication number Publication date
EP0404133A3 (en) 1991-05-02
EP0404133A2 (en) 1990-12-27
DE59005318D1 (en) 1994-05-19
DE3920021C1 (en) 1990-05-17

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