EP0253181B1 - Fastening device for disc-like tools on a tool spindle of a portable electric machine tool - Google Patents

Fastening device for disc-like tools on a tool spindle of a portable electric machine tool Download PDF

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Publication number
EP0253181B1
EP0253181B1 EP87109270A EP87109270A EP0253181B1 EP 0253181 B1 EP0253181 B1 EP 0253181B1 EP 87109270 A EP87109270 A EP 87109270A EP 87109270 A EP87109270 A EP 87109270A EP 0253181 B1 EP0253181 B1 EP 0253181B1
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EP
European Patent Office
Prior art keywords
tool
spindle
clamping
piston
actuating mechanism
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
EP87109270A
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German (de)
French (fr)
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EP0253181A2 (en
EP0253181A3 (en
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C&E Fein GmbH and Co
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C&E Fein GmbH and Co
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Publication of EP0253181A2 publication Critical patent/EP0253181A2/en
Publication of EP0253181A3 publication Critical patent/EP0253181A3/en
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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B24—GRINDING; POLISHING
    • B24B—MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
    • B24B45/00—Means for securing grinding wheels on rotary arbors
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B24—GRINDING; POLISHING
    • B24B—MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
    • B24B45/00—Means for securing grinding wheels on rotary arbors
    • B24B45/006—Quick mount and release means for disc-like wheels, e.g. on power tools
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B24—GRINDING; POLISHING
    • B24B—MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
    • B24B23/00—Portable grinding machines, e.g. hand-guided; Accessories therefor
    • B24B23/02—Portable grinding machines, e.g. hand-guided; Accessories therefor with rotating grinding tools; Accessories therefor
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T83/00—Cutting
    • Y10T83/929—Tool or tool with support
    • Y10T83/9372—Rotatable type
    • Y10T83/9377—Mounting of tool about rod-type shaft
    • Y10T83/9379—At end of shaft

Definitions

  • the invention relates to a device for fastening a disk-shaped tool to the motor-driven tool spindle of a portable power tool of the type specified in the preamble of claim 1.
  • the device is particularly suitable for fastening the grinding wheel to the tool spindle of a portable angle grinder. In the same way, circular saw blades, cutting discs and similar tools can also be attached.
  • a device on an angle grinder of this type is known (DE-C-34 05 885), by means of which the grinding wheels can be assembled and removed by hand using an actuating mechanism integrated in the machine without additional tools.
  • a rotary lever is provided there, which acts on a tension anchor that is axially displaceable in the tool spindle designed as a hollow shaft.
  • the tensioning anchor can be moved against the force of a compression spring in such a way that the flange-like tensioning nut screwed onto its free end is lifted off the grinding wheel and can thus be easily released by hand.
  • the tension anchor is non-rotatably connected to the tool spindle via a toothing. Since the compression spring increases most of the clamping force acting on the grinding wheel has certain minimum dimensions required, so that the known device is particularly suitable for larger angle grinders, especially for two-hand angle grinders.
  • the invention has for its object to further develop the known device for fastening a disk-shaped tool of the type specified in such a way that, due to its more compact design, it is also suitable for smaller portable electric machine tools, in particular for single-handed machines.
  • the invention is based on the idea that when the tool is clamped in, there should be a sufficient frictional connection between the clamping flange, the tool and the counterflange and thus also between the tool spindle and the clamping anchor, while the clamping flange should be relieved to release the tool so that it is unscrewed from the clamping anchor can.
  • these states are made possible by the fact that the tension anchor and the tool spindle delimit a common cavity defining a variable axial distance between facing boundary surfaces of these parts, which cavity is connected to a second cavity arranged in the tension anchor or in the tool spindle and that the cavities are connected to a continuous plastic mass for hydraulic pressure transmission are filled.
  • a piston which can be displaced by changing the cavity volume and locked in the clamping position is arranged.
  • the first cavity is on the hollow shaft by a boundary surface pointing to the side of the actuating mechanism and by a boundary surface opposite this, facing the tool side Spannaker delimits, while the tension anchor has an open to the side of the actuating mechanism, reaching to the second cavity axial bore for receiving the piston.
  • the cavities are expediently connected to one another via essentially radially aligned bores in the tension anchor.
  • the cavity delimitation surface of the tool spindle can be formed by the inner end face of a cylinder sleeve rigidly inserted into the hollow shaft from the tool side, through the axial bore of which the tension anchor engages with a screw pin carrying the tension flange nut at its end, while the tension anchor one of the inner face of the sleeve can have opposite shoulder as a cavity boundary surface.
  • the actuating mechanism has a thrust piece which can be axially displaced in the gear housing and which bears against an axial bearing surface of the piston via a rotary bearing which absorbs axial forces and is preferably designed as a needle bearing .
  • the actuating mechanism has a threaded spindle which is guided in a threaded bore of the tension anchor and which, on its end face facing the second cavity, bears directly with its end face or indirectly via a loose piston against the surface of the plastic mass.
  • the thread of the threaded spindle and the threaded bore is expediently designed to be self-locking.
  • the threaded spindle optionally engages together with the tension anchor on the side opposite the tool through an opening in the gear housing, the threaded spindle on the outside of the gear housing having a preferably knurled actuating head.
  • the threaded spindle with the actuating head has a dual function: by turning the spindle, the piston can be axially displaced in the second cavity, thereby changing the clamping state.
  • plastic mass is pressed from the second cavity into the first cavity and the clamping flange is pulled over the clamping anchor with intermediate clamping of the disk-shaped tool against the abutment on the tool spindle.
  • the spindle in the relaxed state of the tension anchor can be moved against the tool spindle by axial pressure against the spindle head so that the clamping flange is relaxed by increasing the distance to the abutment and can therefore be easily removed from the tension anchor.
  • plastic mass overflows from the first cavity, which becomes smaller as it moves, into the second cavity containing the piston.
  • the actuating end of the threaded spindle which is accessible from the outside, can be covered against accidental access by a cover articulated on the gear housing for safety reasons.
  • the cover has a cover closure, which is preferably designed as a snap-in connection and is only effective or can be latched in when the actuating mechanism is in the tensioned state.
  • a safety switch which can be triggered by the cover or the cover lock can also be provided, which ensures that the machine can only be started when the cover is closed.
  • a compression spring acting counter to the clamping direction can be provided according to the invention in a cavity between the tool spindle and the anchor, which can be designed as a coil spring or a plate spring package.
  • the compression spring is to be designed so that its compressive force is greater than the displacement resistance between the tool spindle and the tension anchor, including the deformation and flow resistances to be overcome during displacement in the area of the plastic mass.
  • toothing grooves are arranged in the piston wall and the associated cavity wall for receiving a part of the plastic mass.
  • plastic mass is best suited for the device according to the invention.
  • the use of all available plastic masses would be possible, provided that these remain permanently plastic.
  • the plastic mass comprises polyvinyl chloride (PVC) with a relatively low degree of polymerization, since this plastic mass largely meets the requirements for portable power tools.
  • the boundary surface assigned to the tension anchor that is to say the part of the boundary surface which points towards the tool side, is at least 50: 1 to a cross-sectional surface of the piston, since such a transmission ratio is at the device according to the invention allows a sufficiently large clamping force for clamping the tool with a still acceptable operating force.
  • the ratio is 100: 1 or even 200: 1 for large portable hand tools.
  • the angle grinder essentially consists of an electric motor arranged in a motor housing 10, an adjoining bevel gear 14 arranged in a gear housing 12 for driving a tool spindle 18 and a grinding wheel 28 which can be fastened to the tool spindle 18 with the aid of a clamping device.
  • the tool spindle 18 designed as a hollow shaft is mounted in two radial roller bearings 16 in the gear housing 12. It has an abutment 20 at its end protruding from the gear housing, against which the grinding wheel 28 can be pressed with the aid of a clamping flange 26.
  • the clamping flange 26, which is designed as a threaded nut, can be screwed onto the threaded pin 24 of a clamping armature 22 which is mounted in the interior of the hollow shaft 18 in a rotationally fixed but displaceable manner in the axial direction.
  • the stub shaft 23 of the tension armature 22 engages through the axial bore 31 of a sleeve 30 inserted from below into the hollow shaft 18 and secured with a snap ring 32 and projects with its threaded pin 24 beyond the flange-side end of the hollow shaft 18.
  • An annular cavity 39 is delimited by the inwardly facing end face 34 of the sleeve 30, the adjoining axial inner surface of the hollow shaft 18 and the shoulder 36 of the tension anchor 22 opposite the sleeve 30, said cavity 39 having radial bores 42 in the tension anchor 22 with a second cavity 44 connected is.
  • a piston 46 engages in the axial bore 45 leading to the second cavity 44, the end face 47 of which delimits the cavity 44. By moving the piston 46 in the axial bore 45 with the aid of an actuating mechanism 54, the volume of the cavity 44 can be changed within certain limits.
  • the cavities 39, 44 are filled with a plastically deformable, essentially incompressible mass 40 which is connected via the bore 42.
  • the mass consists, for example, of PVC with a relatively low degree of polymerization, which in at elevated temperature is filled in liquid state and has a gelatinous plastic consistency at ambient temperature.
  • further chambers 37 open to the cavity 39, for receiving plastic mass 40 can be arranged.
  • the piston 46 In the tensioned position of the actuating mechanism 54, the piston 46 is pushed farthest into the cavity 44. The piston 46 is held by the actuating mechanism in its inserted position, so that a largely rigid connection between the piston 46, the tension anchor 22, the plastic mass 40 and the hollow shaft 18 is created, while the grinding wheel 28 between the clamping flange 26 and the abutment 20 firmly is jammed.
  • the piston 46 like the other parts mentioned, is also rotated about the spindle axis by the driven tool spindle 18.
  • an axial rotary bearing 50 which is preferably designed as a needle bearing, is arranged between the pressure piece 52 and the bearing plate 48 of the piston (FIGS. 1 and 2).
  • the actuating mechanism 54 is released by lifting the eccentric lever 55 (FIG. 1) or by turning the rotary lever 58 (FIG. 2), the pressure piece 52 becomes lifted from the bearing plate 48 of the piston 46. Since the piston 46 can be displaced axially by the play that has now become free, plastic material 40 can be displaced out of the cavity 39 into the cavity 44 by the application of a force acting on the tension anchor 22, and the tension anchor 22 can be shifted downward by a corresponding amount relative to the hollow shaft 18 will.
  • the force can be applied, for example, by an axially acting compression spring 60 designed as a disk spring package, which can be arranged in an annular space 62 between the hollow shaft 18 and the tension anchor 22 (FIG.
  • the clamping flange 26 is lifted off the grinding wheel 28. Since it is no longer necessary to overcome the full contact pressure between the clamping flange 26 and the grinding wheel 28 to loosen the clamping flange 26, the clamping flange nut 26, which is preferably provided with knurling, can easily be unscrewed by hand from the threaded pin 24 and the grinding wheel 28 removed.
  • the grinding wheel 28 is first plugged onto the threaded pin 24 and then moved against the abutment 20 with the clamping flange nut 26 screwed onto the threaded pin 24 by hand.
  • the piston 46 is pushed into the axial bore 45, so that plastic mass 40 is displaced from the cavity 44 into the cavity 39 becomes.
  • the tension anchor 22 is drawn back into the hollow shaft 18, increasing the distance between the boundary surfaces 34, 36 on the side of the threaded pin 24, and the tension flange 26 is pressed against the abutment 20 with the grinding wheel 28 being clamped in between.
  • the direction of rotation of the tool spindle 18 and the thread pitch on the threaded pin 24 are coordinated with one another in such a way that the clamping flange nut 26 automatically tightens when the motor starts.
  • the actuating member is designed as a threaded spindle 46 'which is guided in a threaded bore 45 of the tension anchor 22.
  • the threaded spindle 46 ' engages through an opening 66 provided with a seal 67 in the gear housing 12, while in the case of FIG. 4 the tension anchor 22 is guided outwards through the housing opening 66 together with the threaded spindle 46'.
  • the threaded spindle carries an actuating head 72 which is provided with knurling and which, when the actuating mechanism 54 is in the tensioned state, is overlapped by a hinged cover 68 articulated on the gear housing 12.
  • the hinged lid 68 can only be closed on the lid closure 70 for safety reasons when the actuating spindle 46 'is in the clamping position.
  • the lid closure 70 can have a safety switch, not shown, which interrupts the power supply to the drive motor when the lid is open.
  • the actuating spindle 46 forms with its end face itself the piston 46 acting against the plastic mass 40, while in the exemplary embodiment according to FIG. 4 a loose piston 46 is arranged in the second cavity 44, onto which one the spindle 46 'acts on the end face molded pin 64.

Description

Die Erfindung betrifft eine Einrichtung zur Befestigung eines scheibenförmigen Werkzeugs an der motorisch angetriebenen Werkzeugspindel einer tragbaren Elektrowerkzeugmaschine der im Oberbegriff des Anspruchs 1 angegebenen Gattung. Die Einrichtung ist vor allem zur Befestigung der Schleifscheibe an der Werkzeugspindel einer tragbaren Winkelschleifmaschine geeignet. Auf die gleiche Weise können aber auch Kreissägeblätter, Trennscheiben und dergleichen Werkzeuge befestigt werden.The invention relates to a device for fastening a disk-shaped tool to the motor-driven tool spindle of a portable power tool of the type specified in the preamble of claim 1. The device is particularly suitable for fastening the grinding wheel to the tool spindle of a portable angle grinder. In the same way, circular saw blades, cutting discs and similar tools can also be attached.

Es ist eine Einrichtung an einer Winkelschleifmaschine dieser Art bekannt (DE-C-34 05 885), mit deren Hilfe die Schleifscheiben unter Verwendung eines in der Maschine integrierten Betätigungsmechanismus ohne zusätzliche Werkzeuge von Hand montiert und abgenommen werden können. Zu diesem Zweck ist dort ein Drehhebel vorgesehen, der auf einen in der als Hohlwelle ausgebildeten Werkzeugspindel axial verschiebbaren Spannanker einwirkt. Der Spannanker kann entgegen der Kraft einer Druckfeder so verschoben werden, daß die an seinem freien Ende aufgeschraubte flanschartige Spannmutter von der Schleifscheibe abgehoben wird und dadurch leicht von Hand gelöst werden kann. Der Spannanker ist über eine Verzahnung drehfest mit der Werkzeugspindel verbunden. Da die Druckfeder den überwiegenden Teil der auf die Schleifscheibe einwirkenden Spannkraft zu übernehmen hat, sind gewisse Mindestabmessungen erforderlich, so daß die bekannte Einrichtung vor allem für größere Winkelschleifmaschinen, insbesondere für Zweihand-Winkelschleifmaschinen geeignet ist.A device on an angle grinder of this type is known (DE-C-34 05 885), by means of which the grinding wheels can be assembled and removed by hand using an actuating mechanism integrated in the machine without additional tools. For this purpose, a rotary lever is provided there, which acts on a tension anchor that is axially displaceable in the tool spindle designed as a hollow shaft. The tensioning anchor can be moved against the force of a compression spring in such a way that the flange-like tensioning nut screwed onto its free end is lifted off the grinding wheel and can thus be easily released by hand. The tension anchor is non-rotatably connected to the tool spindle via a toothing. Since the compression spring increases most of the clamping force acting on the grinding wheel has certain minimum dimensions required, so that the known device is particularly suitable for larger angle grinders, especially for two-hand angle grinders.

Der Erfindung liegt die Aufgabe zugrunde, die bekannte Einrichtung zur Befestigung eines scheibenförmigen Werkzeugs der eingangs angegebenen Art dahingehend weiterzubilden, daß sie aufgrund ihrer kompakteren Bauweise auch für kleinere tragbare Elektrowerkzeugmaschinen, insbesondere für Einhand-Maschinen geeignet ist.The invention has for its object to further develop the known device for fastening a disk-shaped tool of the type specified in such a way that, due to its more compact design, it is also suitable for smaller portable electric machine tools, in particular for single-handed machines.

Zur Lösung dieser Aufgabe werden die Merkmale des Anspruches 1 vorgeschlagen. Weitere vorteilhafte Ausgestaltungen und Weiterbildungen der Erfindung ergeben sich aus den Unteransprüchen.To achieve this object, the features of claim 1 are proposed. Further advantageous refinements and developments of the invention result from the subclaims.

Die Erfindung geht von dem Gedanken aus, daß bei eingespanntem Werkzeug ein ausreichender Kraftschluß zwischen Spannflansch, Werkzeug und Gegenflansch und damit auch zwischen der Werkzeugspindel und dem Spannanker bestehen sollte, während zum Lösen des Werkzeugs der Spannflansch entlastet werden sollte, damit er vom Spannanker abgeschraubt werden kann. Erfindungsgemäß werden diese Zustände dadurch ermöglicht, daß der Spannanker und die Werkzeugspindel einen gemeinsamen, einen variablen axialen Abstand zwischen einander zugewandten Begrenzungsflächen dieser Teile definierenden Hohlraum begrenzen, der mit einem im Spannanker oder in der Werkzeugspindel angeordneten zweiten Hohlraum in Verbindung steht und daß die Hohlräume mit einer zusammenhängenden plastischen Masse zur hydraulischen Druckübertragung ausgefüllt sind. Im zweiten Hohlraum ist zusätzlich ein unter Änderung des Hohlraumvolumens verschiebbarer und in der Spannstellung arretierbarer Kolben angeordnet.The invention is based on the idea that when the tool is clamped in, there should be a sufficient frictional connection between the clamping flange, the tool and the counterflange and thus also between the tool spindle and the clamping anchor, while the clamping flange should be relieved to release the tool so that it is unscrewed from the clamping anchor can. According to the invention, these states are made possible by the fact that the tension anchor and the tool spindle delimit a common cavity defining a variable axial distance between facing boundary surfaces of these parts, which cavity is connected to a second cavity arranged in the tension anchor or in the tool spindle and that the cavities are connected to a continuous plastic mass for hydraulic pressure transmission are filled. In the second cavity is In addition, a piston which can be displaced by changing the cavity volume and locked in the clamping position is arranged.

Gemäß einer bevorzugten Ausgestaltung der Erfindung, bei welcher die Werkzeugspindel als Hohlwelle ausgebildet und der Spannanker innerhalb der Hohlwelle axial geführt ist, ist der erste Hohlraum durch eine zur Seite des Betätigungsmechanismus weisende Begrenzungsfläche an der Hohlwelle und durch eine dieser gegenüberliegende, zur Werkzeugseite weisende Begrenzungsfläche am Spannaker begrenzt, während der Spannanker eine zur Seite des Betätigungsmechanismus hin offene, bis zum zweiten Hohlraum reichende axiale Bohrung zur Aufnahme des Kolbens aufweist. Die Hohlräume sind dabei zweckmäßig über im wesentlichen radial ausgerichtete Bohrungen im Spannanker miteinander verbunden.According to a preferred embodiment of the invention, in which the tool spindle is designed as a hollow shaft and the tension anchor is guided axially within the hollow shaft, the first cavity is on the hollow shaft by a boundary surface pointing to the side of the actuating mechanism and by a boundary surface opposite this, facing the tool side Spannaker delimits, while the tension anchor has an open to the side of the actuating mechanism, reaching to the second cavity axial bore for receiving the piston. The cavities are expediently connected to one another via essentially radially aligned bores in the tension anchor.

Die Hohlraumbegrenzungsfläche der Werkzeugspindel kann durch die innere Stirnfläche einer von der Werkzeugseite her in die Hohlwelle starr eingesetzten Zylinderhülse gebildet sein, durch deren Axialbohrung der Spannanker mit einem an seinem Ende die Spannflansch-Mutter tragenden Schraubzapfen hindurchgreift, während der Spannanker eine der inneren Stirnfläche der Hülse gegenüberliegende Schulter als Hohlraumbegrenzungsfläche aufweisen kann.The cavity delimitation surface of the tool spindle can be formed by the inner end face of a cylinder sleeve rigidly inserted into the hollow shaft from the tool side, through the axial bore of which the tension anchor engages with a screw pin carrying the tension flange nut at its end, while the tension anchor one of the inner face of the sleeve can have opposite shoulder as a cavity boundary surface.

Damit sich der Kolben beim Betrieb des Elektrowerkzeugs um die Spindelachse mitdrehen und zum Scheibenwechsel trotzdem axial verschoben werden kann, weist der Betätigungsmechanismus ein im Getriebegehäuse axial verschiebbares Druckstück auf, das über ein Axialkräfte aufnehmendes, vorzugsweise als Nadellager ausgebildetes Drehlager gegen eine axiale Lagerfläche des Kolbens anliegt.So that the piston rotates around the spindle axis during operation of the power tool and can nevertheless be axially displaced when changing the disc, the actuating mechanism has a thrust piece which can be axially displaced in the gear housing and which bears against an axial bearing surface of the piston via a rotary bearing which absorbs axial forces and is preferably designed as a needle bearing .

Gemäß einer weiteren vorteilhaften Ausgestaltung der Erfindung weist der Betätigungsmechanismus eine in einer Gewindebohrung des Spannankers geführte Gewindespindel auf, die auf ihrer dem zweiten Hohlraum zugewandten Stirnseite unmittelbar mit ihrer Stirnfläche oder mittelbar über einen losen Kolben gegen die Oberfläche der plastischen Masse anliegt. Das Gewinde der Gewindespindel und der Gewindebohrung ist dabei zweckmäßig selbsthemmend ausgebildet. Vorteilhafterweise greift die Gewindespindel gegebenenfalls zusammen mit dem Spannanker auf der dem Werkzeug gegenüberliegenden Seite durch eine Öffnung im Getriebegehäuse hindurch, wobei die Gewindespindel auf der Außenseite des Getriebegehäuses einen vorzugsweise gerändelten Betätigungskopf aufweisen kann. Der Gewindespindel mit dem Betätigungskopf kommt dabei eine doppelte Funktion zu: Durch Drehen der Spindel kann der Kolben im zweiten Hohlraum axial verschoben und dadurch der Spannzustand verändert werden. Beim Spannvorgang wird dabei plastische Masse aus dem zweiten Hohlraum in den ersten Hohlraum gedrückt und dabei der Spannflansch über den Spannanker unter Zwischenklemmen des scheibenförmigen Werkzeugs gegen das Widerlager an der Werkzeugspindel gezogen. Umgekehrt kann nach erfolgtem Herausdrehen der Spindel in den entspannten Zustand der Spannanker durch axialen Druck gegen den Spindelkopf so gegenüber der Werkzeugspindel verschoben werden, daß der Spannflansch durch Vergrößerung des Abstands zum Widerlager entspannt und dadurch leicht vom Spannanker abgenommen werden kann. Gleichzeitig strömt hierbei plastische Masse aus dem beim Verschieben kleiner werdenden ersten Hohlraum in den zweiten, den Kolben enthaltenden Hohlraum über.According to a further advantageous embodiment of the invention, the actuating mechanism has a threaded spindle which is guided in a threaded bore of the tension anchor and which, on its end face facing the second cavity, bears directly with its end face or indirectly via a loose piston against the surface of the plastic mass. The thread of the threaded spindle and the threaded bore is expediently designed to be self-locking. Advantageously, the threaded spindle optionally engages together with the tension anchor on the side opposite the tool through an opening in the gear housing, the threaded spindle on the outside of the gear housing having a preferably knurled actuating head. The threaded spindle with the actuating head has a dual function: by turning the spindle, the piston can be axially displaced in the second cavity, thereby changing the clamping state. During the clamping process, plastic mass is pressed from the second cavity into the first cavity and the clamping flange is pulled over the clamping anchor with intermediate clamping of the disk-shaped tool against the abutment on the tool spindle. Conversely, after unscrewing the spindle in the relaxed state of the tension anchor can be moved against the tool spindle by axial pressure against the spindle head so that the clamping flange is relaxed by increasing the distance to the abutment and can therefore be easily removed from the tension anchor. At the same time, plastic mass overflows from the first cavity, which becomes smaller as it moves, into the second cavity containing the piston.

Das von der Außenseite her zugängliche Betätigungsende der Gewindespindel ist aus Sicherheitsgründen durch einen am Getriebegehäuse angelenkten Deckel gegen versehentlichen Zugriff abdeckbar. Der Deckel weist dabei einen vorzugsweise als Rastverbindung ausgebildeten Deckelverschluß auf, der nur im Spannzustand des Betätigungsmechanismus wirksam bzw. einrastbar ist. Zusätzlich kann auch ein durch den Deckel oder den Deckelverschluß auslösbarer Sicherheitsschalter vorgesehen werden, der gewährleisetet, daß die Maschine nur bei geschlossenem Deckel in Betrieb gesetzt werden kann.The actuating end of the threaded spindle, which is accessible from the outside, can be covered against accidental access by a cover articulated on the gear housing for safety reasons. The cover has a cover closure, which is preferably designed as a snap-in connection and is only effective or can be latched in when the actuating mechanism is in the tensioned state. In addition, a safety switch which can be triggered by the cover or the cover lock can also be provided, which ensures that the machine can only be started when the cover is closed.

Um ein selbsttätiges Entspannen der Einspannvorrichtung beim Öffenen des Betätigungsmechanismus zu gewährleisten kann gemäß der Erfindung in einem Hohlraum zwischen Werkzeugspindel und Spannanker eine entgegen der Einspannrichtung wirkende Druckfeder vorgesehen werden, die als Schraubenfeder oder Tellerfedernpaket ausgebildet sein kann. Die Druckfeder ist dabei so auszulegen, daß ihre Druckkraft größer als der Verschiebewiderstand zwischen Werkzeugspindel und Spannanker einschließlich der beim Verschieben zu überwindenden Verformungs- und Strömungswiderstände im Bereich der plastischen Masse ist.In order to ensure an automatic relaxation of the clamping device when the actuating mechanism is opened, a compression spring acting counter to the clamping direction can be provided according to the invention in a cavity between the tool spindle and the anchor, which can be designed as a coil spring or a plate spring package. The compression spring is to be designed so that its compressive force is greater than the displacement resistance between the tool spindle and the tension anchor, including the deformation and flow resistances to be overcome during displacement in the area of the plastic mass.

Um zu gewährleisten, daß der lose Kolben im zweiten Hohlraum nur axial verschoben aber beim Verdrehen der Betätigungsspindel nicht mitgedreht wird, sind in der Kolbenwandung und der zugehörigen Hohlraumwandung Verzahnungsnuten zur Aufnahme eines Teils der plastischen Masse angeordnet.To ensure that the loose piston in the second cavity is only axially displaced but is not rotated when the actuating spindle is rotated, toothing grooves are arranged in the piston wall and the associated cavity wall for receiving a part of the plastic mass.

Bei den bisherigen Ausführungsbeispielen wurde im einzelnen nicht näher erläutert, welche plastische Masse sich am besten für die erfindungsgemäße Einrichtung eignet. Grundsätzlich wäre hier die Verwendung von sämtlichen zur Verfügung stehenden plastischen Massen möglich, sofern diese dauerhaft plastisch bleiben. Am vorteilhaftesten hat es sich jedoch erwiesen, wenn die plastische Masse Polyvinylchlorid (PVC) mit relativ niedrigem Polymerisationsgrad umfaßt, da diese plastische Masse den Anforderungen bei tragbaren Elektrowerkzeugen weitestgehend gerecht wird.In the previous exemplary embodiments it has not been explained in detail which plastic mass is best suited for the device according to the invention. In principle, the use of all available plastic masses would be possible, provided that these remain permanently plastic. However, it has proven to be most advantageous if the plastic mass comprises polyvinyl chloride (PVC) with a relatively low degree of polymerization, since this plastic mass largely meets the requirements for portable power tools.

Bei einem weiteren vorteilhaften Ausführungsbeispiel hat es sich als günstig erwiesen,wenn die dem Spannanker zugeordnete Begrenzungsfläche, d. h. der Teil der Begrenzungsfläche, welcher zur Werkzeugseite hin weist, zu einer Querschnittsfläche des Kolbens im Verhältnis von mindestens 50 : 1 steht, da ein derartiges Übersetzungsverhältnis bei der erfindungsgemäßen Einrichtung eine für ein Spannen des Werkzeugs ausreichend große Spannkraft bei noch vertretbar großer Betätigungskraft erlaubt. Noch vorteilhafter ist es jedoch, wenn das Verhältnis 100 : 1 oder bei großen tragbaren Handwerkzeugen gegebenenfalls sogar 200 : 1 beträgt.In a further advantageous exemplary embodiment, it has proven to be advantageous if the boundary surface assigned to the tension anchor, that is to say the part of the boundary surface which points towards the tool side, is at least 50: 1 to a cross-sectional surface of the piston, since such a transmission ratio is at the device according to the invention allows a sufficiently large clamping force for clamping the tool with a still acceptable operating force. However, it is even more advantageous if the ratio is 100: 1 or even 200: 1 for large portable hand tools.

Im folgenden wird die Erfindung anhand der in der Zeichnung in schematischer Weise dargestellten Ausführungsbeispiele näher erläutert. Es zeigen

Fig. 1
einen senkrechten Schnitt durch das Getriebegehäuse einer Winkelschleifmaschine mit Exzenterhebel als Betätigungsorgan für die Spannvorrichtung;
Fig. 2
einen senkrechten Schnitt durch eine Winkelschleifmaschine mit Drehhebel als Betätigungsorgan für die Spannvorrichtung;
Fig. 3
einen senkrechten Schnitt durch eine Winkelschleifmaschine mit Gewindespindel und gerändeltem Betätigungskopf als Betätigungsorgan für die Spannvorrichtung;
Fig. 4
einen senkrechten Schnitt durch eine Winkelschleifmaschine mit Gewindespindel und losem Kolben als Betätigungsorgan für die Spannvorrichtung;
Fig. 5
einen Schnitt entlang der Schnittlinie 5-5 der Fig. 4.
The invention is explained in more detail below on the basis of the exemplary embodiments shown schematically in the drawing. Show it
Fig. 1
a vertical section through the gear housing of an angle grinder with an eccentric lever as an actuator for the clamping device;
Fig. 2
a vertical section through an angle grinder with rotary lever as an actuator for the clamping device;
Fig. 3
a vertical section through an angle grinder with threaded spindle and knurled actuating head as an actuator for the clamping device;
Fig. 4
a vertical section through an angle grinder with threaded spindle and loose piston as an actuator for the clamping device;
Fig. 5
a section along the section line 5-5 of FIG. 4th

Die Winkelschleifmaschine besteht im wesentlichen aus einem in einem Motorgehäuse 10 angeordneten Elektromotor, einem daran anschließenden in einem Getriebegehäuse 12 angeordneten Kegelradgetriebe 14 für den Antrieb einer Werkzeugspindel 18 sowie einer mit Hilfe einer Spannvorrichtung an der Werkzeugspindel 18 befestigbaren Schleifscheibe 28.The angle grinder essentially consists of an electric motor arranged in a motor housing 10, an adjoining bevel gear 14 arranged in a gear housing 12 for driving a tool spindle 18 and a grinding wheel 28 which can be fastened to the tool spindle 18 with the aid of a clamping device.

Die als Hohlwelle ausgebildete Werkzeugspindel 18 ist in zwei radialen Wälzlagern 16 im Getriebegehäuse 12 gelagert. Sie weist an ihrem aus dem Getriebegehäuse herausragenden Ende ein Widerlager 20 auf, gegen das die Schleifscheibe 28 mit Hilfe eines Spannflanschs 26 anpreßbar ist. Der als Gewindemutter ausgebildete Spannflansch 26 ist auf den Gewindezapfen 24 eines im Inneren der Hohlwelle 18 drehfest aber in axialer Richtung verschiebbar gelagerten Spannankers 22 aufschraubbar. Der Wellenstumpf 23 des Spannankers 22 greift durch die axiale Bohrung 31 einer von unten her in die Hohlwelle 18 eingesetzten und mit einem Sprengring 32 gesicherten Hülse 30 hindurch und steht mit seinem Gewindezapfen 24 über das flanschseitige Ende der Hohlwelle 18 über. Durch die nach innen weisende Stirnfläche 34 der Hülse 30, die daran anschließende axiale Innenfläche der Hohlwelle 18 und die der Hülse 30 gegenüberliegende Schulter 36 des Spannankers 22 wird ein ringförmiger Hohlraum 39 begrenzt, der über radiale Bohrungen 42 im Spannanker 22 mit einem zweiten Hohlraum 44 verbunden ist. In die zum zweiten Hohlraum 44 führende axiale Bohrung 45 greift ein Kolben 46 ein, dessen Stirnfläche 47 den Hohlraum 44 begrenzt. Durch Verschieben des Kolbens 46 in der axialen Bohrung 45 mit Hilfe eines Betätigungsmechanismus 54 kann das Volumen des Hohlraums 44 in gewissen Grenzen verändert werden.The tool spindle 18 designed as a hollow shaft is mounted in two radial roller bearings 16 in the gear housing 12. It has an abutment 20 at its end protruding from the gear housing, against which the grinding wheel 28 can be pressed with the aid of a clamping flange 26. The clamping flange 26, which is designed as a threaded nut, can be screwed onto the threaded pin 24 of a clamping armature 22 which is mounted in the interior of the hollow shaft 18 in a rotationally fixed but displaceable manner in the axial direction. The stub shaft 23 of the tension armature 22 engages through the axial bore 31 of a sleeve 30 inserted from below into the hollow shaft 18 and secured with a snap ring 32 and projects with its threaded pin 24 beyond the flange-side end of the hollow shaft 18. An annular cavity 39 is delimited by the inwardly facing end face 34 of the sleeve 30, the adjoining axial inner surface of the hollow shaft 18 and the shoulder 36 of the tension anchor 22 opposite the sleeve 30, said cavity 39 having radial bores 42 in the tension anchor 22 with a second cavity 44 connected is. A piston 46 engages in the axial bore 45 leading to the second cavity 44, the end face 47 of which delimits the cavity 44. By moving the piston 46 in the axial bore 45 with the aid of an actuating mechanism 54, the volume of the cavity 44 can be changed within certain limits.

Die Hohlräume 39,44 sind mit einer über die Bohrung 42 zusammenhängenden, plastisch verformbaren, im wesentlichen inkompressiblen Masse 40 ausgefüllt. Die Masse besteht beispielsweise aus PVC mit relativ niedrigem Polymerisationsgrad, das bei erhöhter Temperatur in flüssigem Zustand eingefüllt wird und bei Umgebungstemperatur eine gallertartige plastische Konsistenz besitzt. In den Hohlraumbegrenzungswänden 34,36 können weitere, zum Hohlraum 39 hin offene Kammern 37 zur Aufnahme von plastischer Masse 40 angeordnet sein. Beim Verschieben des Kolbens 46 in der Bohrung 45 wird ein Teil der Masse 40 unter Veränderung der Verschiebelage des Spannankers 22 je nach Richtung der Verschiebebewegung in den einen oder anderen Hohlraum 39 bzw. 44 verdrängt.The cavities 39, 44 are filled with a plastically deformable, essentially incompressible mass 40 which is connected via the bore 42. The mass consists, for example, of PVC with a relatively low degree of polymerization, which in at elevated temperature is filled in liquid state and has a gelatinous plastic consistency at ambient temperature. In the cavity delimitation walls 34, 36, further chambers 37, open to the cavity 39, for receiving plastic mass 40 can be arranged. When the piston 46 is displaced in the bore 45, part of the mass 40 is displaced into one or the other cavity 39 or 44 depending on the direction of the displacement movement, changing the displacement position of the tensioning anchor 22.

In der Spannstellung des Betätigungsmechanismus 54 is der Kolben 46 am weitesten in den Hohlraum 44 hinein verschoben. Der Kolben 46 wird dabei durch den Betätigungsmechanismus in seiner eingeschobenen Stellung festgehalten, so daß ein weitgehend starrer Verbund zwischen dem Kolben 46, dem Spannanker 22, der plastischen Masse 40 und der Hohlwelle 18 entsteht, während die Schleifscheibe 28 zwischen Spannflansch 26 und Widerlager 20 fest eingeklemmt ist. Der Kolben 46 wird ebenso wie die übrigen genannten Teile durch die angetriebene Werkzeugspindel 18 um die Spindelachse mitgedreht. Um die Drehung zu ermöglichen, ist zwischen dem Druckstück 52 und der Lagerplatte 48 des Kolbens ein vorzugsweise als Nadellager ausgebildetes axiales Drehlager 50 angeordnet (Fig. 1 und 2).In the tensioned position of the actuating mechanism 54, the piston 46 is pushed farthest into the cavity 44. The piston 46 is held by the actuating mechanism in its inserted position, so that a largely rigid connection between the piston 46, the tension anchor 22, the plastic mass 40 and the hollow shaft 18 is created, while the grinding wheel 28 between the clamping flange 26 and the abutment 20 firmly is jammed. The piston 46, like the other parts mentioned, is also rotated about the spindle axis by the driven tool spindle 18. In order to enable the rotation, an axial rotary bearing 50, which is preferably designed as a needle bearing, is arranged between the pressure piece 52 and the bearing plate 48 of the piston (FIGS. 1 and 2).

Wird nun zum Zwecke des Entfernens der Schleifscheibe der Betätigungsmechanismus 54 durch Anheben des Exzenterhebels 55 (Fig. 1) oder durch Drehen des Drehhebels 58 (Fig. 2) gelöst, so wird das Druckstück 52 von der Lagerplatte 48 des Kolbens 46 abgehoben. Da der Kolben 46 um das nun freiegewordene Spiel axial verschiebbar ist, kann durch Aufwendung einer am Spannanker 22 angreifenden Kraft plastisches Material 40 aus dem Hohlraum 39 heraus in den Hohlraum 44 verdrängt und der Spannanker 22 relativ zur Hohlwelle 18 um ein entsprechendes Stück nach unten verschoben werden. Die Kraft kann beispielsweise durch eine als Tellerfedernpaket ausgebildete axial wirkende Druckfeder 60 aufgebracht werden, die in einem Ringraum 62 zwischen Hohlwelle 18 und Spannanker 22 angeordnet werden kann (Fig. 2) und deren Druckkraft größer als der Verschiebewiderstand zwischen diesen Teilen einschließlich Verformungs- und Strömungswiderstand im Bereich der plastischen Masse 40 ist. Die Verschiebung bewirkt, daß der Spannflansch 26 von der Schleifscheibe 28 abgehoben wird. Da zum Lösen des als Mutter ausgebildeten Spannflanschs 26 nicht mehr die volle Anpreßkraft zwischen Spannflansch 26 und Schleifscheibe 28 überwunden werden muß, kann die vorzugsweise mit einer Rändelung versehene Spannflansch-Mutter 26 leicht von Hand von dem Gewindezapfen 24 abgeschraubt und die Schleifscheibe 28 abgenommen werden.If, for the purpose of removing the grinding wheel, the actuating mechanism 54 is released by lifting the eccentric lever 55 (FIG. 1) or by turning the rotary lever 58 (FIG. 2), the pressure piece 52 becomes lifted from the bearing plate 48 of the piston 46. Since the piston 46 can be displaced axially by the play that has now become free, plastic material 40 can be displaced out of the cavity 39 into the cavity 44 by the application of a force acting on the tension anchor 22, and the tension anchor 22 can be shifted downward by a corresponding amount relative to the hollow shaft 18 will. The force can be applied, for example, by an axially acting compression spring 60 designed as a disk spring package, which can be arranged in an annular space 62 between the hollow shaft 18 and the tension anchor 22 (FIG. 2) and whose compressive force is greater than the displacement resistance between these parts, including deformation and flow resistance is in the range of the plastic mass 40. The displacement causes the clamping flange 26 to be lifted off the grinding wheel 28. Since it is no longer necessary to overcome the full contact pressure between the clamping flange 26 and the grinding wheel 28 to loosen the clamping flange 26, the clamping flange nut 26, which is preferably provided with knurling, can easily be unscrewed by hand from the threaded pin 24 and the grinding wheel 28 removed.

Umgekehrt wird die Schleifscheibe 28 bei der Montage zunächst auf den Gewindezapfen 24 gesteckt und danach mit der von Hand auf den Gewindezapfen 24 aufgedrehten Spannflansch-Mutter 26 gegen das Widerlager 20 verschoben. Beim anschließenden Spannen mit Hilfe des Betätigungsmechanismus 54 wird der Kolben 46 in die Axialbohrung 45 eingeschoben, so daß plastische Masse 40 aus dem Hohlraum 44 in den Hohlraum 39 verdrängt wird. Dadurch wird der Spannanker 22 unter Vergrößerung des Abstands zwischen den Begrenzungsflächen 34,36 auf der Seite des Gewindezapfens 24 in die Hohlwelle 18 zurückgezogen und der Spannflansch 26 unter Zwischenklemmen der Schleifscheibe 28 gegen das Widerlager 20 gepreßt. Die Drehrichtung der Werkzeugspindel 18 und die Gewindesteigung auf dem Gewindezapfen 24 sind so aufeinander abgestimmt, daß sich die Spannflansch-Mutter 26 beim Anlaufen des Motors selbsttätig festzieht.Conversely, during assembly, the grinding wheel 28 is first plugged onto the threaded pin 24 and then moved against the abutment 20 with the clamping flange nut 26 screwed onto the threaded pin 24 by hand. During the subsequent clamping with the aid of the actuating mechanism 54, the piston 46 is pushed into the axial bore 45, so that plastic mass 40 is displaced from the cavity 44 into the cavity 39 becomes. As a result, the tension anchor 22 is drawn back into the hollow shaft 18, increasing the distance between the boundary surfaces 34, 36 on the side of the threaded pin 24, and the tension flange 26 is pressed against the abutment 20 with the grinding wheel 28 being clamped in between. The direction of rotation of the tool spindle 18 and the thread pitch on the threaded pin 24 are coordinated with one another in such a way that the clamping flange nut 26 automatically tightens when the motor starts.

Bei den in den Figuren 3 bis 5 gezeigten Ausführungsbeispielen ist das Betätigungsorgan als Gewindespindel 46' ausgebildet, die in einer Gewindebohrung 45 des Spannankers 22 geführt ist. Im Falle der Fig. 3 greift die Gewindespindel 46' durch eine mit einer Dichtung 67 versehene Öffnung 66 im Getriebegehäuse 12 hindurch, während im Falle der Fig. 4 der Spannanker 22 zusammen mit der Gewindespindel 46' durch die Gehäuseöffnung 66 nach außen geführt ist. An ihrem Betätigungsende trägt die Gewindespindel einen mit einer Rändelung versehenen Betätigungskopf 72, der im Spannzustand des Betätigungsmechanismus 54 durch einen am Getriebegehäuse 12 angelenkten Klappdeckel 68 übergriffen wird. Der Klappdeckel 68 läßt sich am Deckelverschluß 70 aus Sicherheitsgründen nur dann verschließen, wenn sich die Betätigungsspindel 46' in der Spannstellung befindet. Gegebenenfalls kann der Deckelverschluß 70 einen nicht dargestellten Sicherheitsschalter aufweisen, der die Stromzufuhr zum Antriebsmotor bei geöffnetem Deckel unterbricht.In the exemplary embodiments shown in FIGS. 3 to 5, the actuating member is designed as a threaded spindle 46 'which is guided in a threaded bore 45 of the tension anchor 22. In the case of FIG. 3, the threaded spindle 46 'engages through an opening 66 provided with a seal 67 in the gear housing 12, while in the case of FIG. 4 the tension anchor 22 is guided outwards through the housing opening 66 together with the threaded spindle 46'. At its actuating end, the threaded spindle carries an actuating head 72 which is provided with knurling and which, when the actuating mechanism 54 is in the tensioned state, is overlapped by a hinged cover 68 articulated on the gear housing 12. The hinged lid 68 can only be closed on the lid closure 70 for safety reasons when the actuating spindle 46 'is in the clamping position. Optionally, the lid closure 70 can have a safety switch, not shown, which interrupts the power supply to the drive motor when the lid is open.

Bei dem in Fig. 3 gezeigten Ausführungsbeispiel bildet die Betätigungsspindel 46' mit ihrer Stirnfläche selbst den gegen die plastische Masse 40 einwirkenden Kolben 46, während bei dem Ausführungsbeispiel nach Fig. 4 ein loser Kolben 46 im zweiten Hohlraum 44 angeordnet ist, auf den ein an der Spindel 46' stirnseitig angeformter Zapfen 64 einwirkt.In the exemplary embodiment shown in FIG. 3, the actuating spindle 46 'forms with its end face itself the piston 46 acting against the plastic mass 40, while in the exemplary embodiment according to FIG. 4 a loose piston 46 is arranged in the second cavity 44, onto which one the spindle 46 'acts on the end face molded pin 64.

Claims (28)

  1. Device for fastening a disc-like tool (28) to a motor-driven tool spindle (18), mounted in a gearbox (12), of a portable electric tool, in particular a grinding wheel to an angle grinder, having a clamping anchor (22) which is displaceable in the tool spindle (18), designed as a hollow shaft, axially relative to the same, is connected to the tool spindle (18) in such a way as to be locked against rotation, and projects at its free end beyond the tool-side end of the tool spindle (18), having a clamping flange (26) which can be detachably fastened to the free end of the clamping anchor (22) and has an abutment (20) arranged on the tool-side end of the tool spindle (18), and having an actuating mechanism (54) for releasably pressing the clamping flange (26) against the abutment (20) with the tool (28) clamped in between, characterised in that the clamping anchor (22) and the tool spindle (18) each have a boundary surface (34, 36), both of which are arranged facing one another at an axial distance apart inside the tool spindle (18) designed as a hollow shaft and together define a first hollow space (39) which in turn is connected to a second hollow space (44) arranged in the clamping anchor (22) or in the tool spindle (18), in that a piston (46) is arranged in the second hollow space (44), which piston (46) can be displaced by the actuating mechanism (54) while the hollow-space volume is changed and can be locked in at least one displacement position, and in that the hollow spaces (39, 44) are filled with a plastic compound (40) for the hydraulic transmission of pressure.
  2. Device according to Claim 1, characterised in that the actuating mechanism (54) is arranged on the side of the gearbox (12) opposite the tool (28), in that the boundary surface (34) allocated to the hollow shaft (18) points towards the side of the actuating mechanism (54), and the boundary surface (36) allocated to the clamping anchor (22) and located opposite the boundary surface (34) points towards the tool side, and in that the clamping anchor (22) has an axial bore (45) for accommodating an actuating rod or spindle (46') for the piston (46), which axial bore (45) is open towards the side of the actuating mechanism (54) and extends down to the second hollow space (44).
  3. Device according to Claim 2, characterised in that the second hollow space (44) designed as an extension of the axial bore (45) is connected via radial bores (42) to the first hollow space (39) defined by the hollow-space boundary surface (34, 36) of the tool spindle (18) and the clamping anchor (22).
  4. Device according to Claim 2 or 3, characterised in that the hollow-space boundary surface (34) of the tool spindle (18) is formed by the inner end face of a cylinder sleeve (30) which is inserted from the tool side into the hollow shaft (18) and through the axial bore (31) of which the clamping anchor (22) passes with a shaft butt (23) carrying at its end the clamping flange (26), and in that the clamping anchor (22) has as a hollow-space boundary surface a shoulder (36) located opposite the inner end face (34) of the sleeve (30).
  5. Device according to Claim 4, characterised in that chambers (37) open towards the hollow space (39) and intended for receiving plastic material (40) are arranged in the hollow-space boundary walls (24, 36).
  6. Device according to one of Claims 1 to 5, characterised in that the actuating mechanism (54) has a thrust piece (52) which is axially displaceable in the gearbox (12) and bears against an axial bearing surface (48) of the piston (46) via a pivot bearing (50) absorbing axial forces.
  7. Device according to Claim 6, characterised in that the pivot bearing (50) is designed as an axial needle bearing.
  8. Device according to one of Claims 1 to 7, characterised in that the actuating mechanism (54) has an eccentric lever (55) acting on the thrust piece (52) guided in the gearbox (12) in such a way as to be locked against rotation.
  9. Device according to one of Claims 1 to 7, characterised in that the actuating mechanism (54) has a rotary lever (58) connected to the thrust piece (52) guided in a thread (56) in the gearbox (12).
  10. Device according to one of Claims 1 to 5, characterised in that the actuating mechanism (54) has a threaded spindle (46') guided in a tapped bore (45) in the clamping anchor (22).
  11. Device according to Claim 10, characterised in that the threaded spindle (46') is designed as a piston (46).
  12. Device according to Claim 10, characterised in that the threaded spindle (46'), with its end face or with a stem (64) integrally formed on the front end, bears against the piston (46) arranged in a floating manner in the second hollow space (44).
  13. Device according to one of Claims 10 to 12, characterised in that the threaded spindle (46') can be rotated in a self-locking manner in the tapped bore (45).
  14. Device according to one of Claims 10 to 13, characterised in that the threaded spindle (46') passes through an opening (66) in the gearbox (12).
  15. Device according to one of Claims 10 to 14, characterised in that the threaded spindle (46') together with the clamping anchor (22) passes through an opening (66) in the gearbox (12).
  16. Device according to Claim 14, characterised in that the threaded spindle (46') is accommodated in the region of the gearbox opening (66) in a pivot bearing having a sealing action.
  17. Device according to Claim 15, characterised in that the clamping anchor (22) is accommodated in the region of the gearbox opening (66) in a pivot bearing (67) having a sealing action.
  18. Device according to one of Claims 10 to 17, characterised in that the threaded spindle (46') has at its actuating end a preferably knurled actuating head (72).
  19. Device according to one of Claims 10 to 18, characterised in that the threaded spindle (46') has at its actuating end a polygonal opening or a polygonal head for a screwdriver or spanner.
  20. Device according to one of Claims 10 to 19, characterised in that the actuating end of the threaded spindle (46') can be covered by a lid (68) arranged, preferably pivotably, on the gearbox (12).
  21. Device according to Claim 20, characterised in that the lid (68) is arranged relative to the actuating mechanism (54) in such a way that a lid lock (70) designed as a catch connection is effective or can be locked only in the clamping position of the actuating mechanism (54).
  22. Device according to Claim 20 or 21, characterised by a safety switch for the power supply of the electric motor, which safety switch can be triggered by the lid (68) or the lid lock (70).
  23. Device according to one of Claims 1 to 22, characterised in that at least one compression spring (60), acting against the clamping direction of the actuating mechanism (54) and preferably designed as a helical spring or a disc-spring stack, is arranged in a hollow space (62) between tool spindle (18) and clamping anchor (22),0 the compression force of which compression spring (60) is greater than the displacement resistance between tool spindle (18) and clamping anchor (22) including deformation and flow resistance of the plastic compound (40).
  24. Device according to one of Claims 1 to 23, characterised in that serrations are provided in the second hollow space (44) and in the piston (46) for the anti-rotation locking of the latter.
  25. Device according to one of the preceding claims, characterised in that the plastic compound comprises polyvinyl chloride (PVC) having a relatively low degree of polymerisation.
  26. Device according to one of the preceding claims, characterised in that the boundary surface (36) allocated to the clamping anchor (22) is in a ratio of at least 50:1 relative to a cross-sectional area of the piston (46).
  27. Device according to Claim 26, characterised in that the ratio of the boundary surface (36) of the clamping anchor (22) to the cross-sectional area of the piston (46) is at least 100:1.
  28. Device according to Claim 27, characterised in that the ratio of the boundary surface (36) of the clamping anchor (22) to the cross-sectional area of the piston (46) is at least 200:1.
EP87109270A 1986-07-12 1987-06-27 Fastening device for disc-like tools on a tool spindle of a portable electric machine tool Expired - Lifetime EP0253181B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE3623555 1986-07-12
DE19863623555 DE3623555A1 (en) 1986-07-12 1986-07-12 FASTENING DEVICE FOR DISC-SHAPED TOOLS ON THE TOOL SPINDLE OF A PORTABLE ELECTRIC TOOL MACHINE

Publications (3)

Publication Number Publication Date
EP0253181A2 EP0253181A2 (en) 1988-01-20
EP0253181A3 EP0253181A3 (en) 1990-01-31
EP0253181B1 true EP0253181B1 (en) 1992-09-16

Family

ID=6305045

Family Applications (1)

Application Number Title Priority Date Filing Date
EP87109270A Expired - Lifetime EP0253181B1 (en) 1986-07-12 1987-06-27 Fastening device for disc-like tools on a tool spindle of a portable electric machine tool

Country Status (5)

Country Link
US (1) US4779382A (en)
EP (1) EP0253181B1 (en)
JP (1) JPS6389267A (en)
KR (1) KR900008485B1 (en)
DE (2) DE3623555A1 (en)

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Also Published As

Publication number Publication date
EP0253181A2 (en) 1988-01-20
EP0253181A3 (en) 1990-01-31
KR900008485B1 (en) 1990-11-22
US4779382A (en) 1988-10-25
JPS6389267A (en) 1988-04-20
DE3623555A1 (en) 1988-02-04
DE3781733D1 (en) 1992-10-22
DE3623555C2 (en) 1988-11-03
KR880001373A (en) 1988-04-23

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