EP0836544B1 - Electric hand-operated grinder - Google Patents

Description

State of the art

The invention is based on an electric hand grinder that defined in the preamble of claim 1 Genus.

In a known electric hand grinder this Kind with a formed as a triangular grinding plate Grinding tools (EP 0 610 801 A1) have the holder side Locking elements of the quick lock one with the Control button one-piece latch on, against the force a compression spring is slidable and a recess carries two bevels forming a locking lug. The tool-side locking elements are of at least formed a locking hook, which is made in one piece from the Sanding plate is formed and from this upwards projects. At on the contact surface of the tool holder the locking hook protrudes into the Recess in the tool holder and is from the Locking nose under the force of the compression spring engaged behind. To the symmetrical grinding plate in any positions rotated by 120 ° at the Being able to attach tool holders is a snap-in hook in everyone the three corners of the grinding plate. The form-locking elements specified by the tool are manufactured by Support claws formed in pairs in each corner of the Sanding plate are arranged symmetrically to the locking hook, while the corresponding, holder side fixed positive locking elements through two engagement openings are realized on the of the control button opposite side of the tool holder are arranged. To change the grinding tool, press the control button against the force of the compression spring shifted, causing the Locking lug releases the locking hook. The sanding plate can now be removed manually from the tool holder. When the grinding plate is reattached, two of the Support claws in the two engagement openings in the Tool holder inserted and the grinding tool is on the contact surface of the tool holder is pressed on. About the the lower ramp slope on the locking lug becomes the Bolt moved against the force of the compression spring until the locking hook is guided past the locking lug. The bolt that springs back again pushes the Locking lug behind the locking hook, which makes Grinding tool immovable in the axial direction on Tool holder is set.

Advantages of the invention

The electric hand grinder according to the invention with the In contrast, features of claim 1 and the grinding tool deposited in claim 10 have the advantage that the quick lock in very inexpensive to manufacture, insensitive to dust, is sturdy and easy to use and a larger one Power transmission from the tool holder to that special tensile, pressure and tilt resistant grinding tools allows. Special grinding tools, such as Flap grinding attachments, grinding tongues or grinding pipes, can due to the design of the quick release device according to the invention both when grinding from "below" as well from above, which in the latter case means that a grinding force also over the top of the Special tool applied and from the tool holder can be included.

By the measures listed in the further claims are advantageous developments and improvements in Claim specified electric hand grinder possible. According to a preferred embodiment of the Invention is the spring wire on the tool holder in a Support surface on the tool holder can be swiveled on a parallel plane held and connected with a control button. He's wearing one essentially the number of hooks on the tool side corresponding number of radially inwards Indentations that are in the locking position for the The swivel position of the spring wire forming the grinding tool Reach behind the hook. Through this constructive design a considerable ease of use when changing tools and at the same time a high locking reliability for the reached grinding tool inserted in the tool holder.

According to a preferred embodiment of the invention, the Spring wire guided in cross slots by webs on a to the rotary bearing coaxial circular line are arranged so that in Locking position of the spring wire one pair of webs each one of the indentations lies on both sides and the web pairs around preferably the same circumferential angles are offset from one another. The ring-shaped spring wire runs approximately radially in two striving, parallel legs, of which one leg at the free end at right angles to the other Leg is bent. At the free end of the two Leg is the control button clipped onto the leg. This constructive design allows the Spring wire and the control button very easy and quick in the one-piece tool holder made of plastic assemble.

According to an advantageous embodiment of the invention the tool and tool holder side Positive locking elements by two axially interlocking Realized polygonal profiles that are coaxial to the axis of the Pivots on facing sides of Grinding tool and tool holder are arranged. Prefers is the tool-side polygon profile on the Inside of a protruding from the top of the grinding tool preferably with this one-piece sleeve and that holder-side polygon profile on the outside of one of the Protruding tool, preferably in one piece, in the Sleeve formed positively insertable pin. The the hooks forming the tool-side locking elements the quick lock are advantageous on the outer wall of the Molded sleeve. This allows all tool-side elements and all holder-side elements when manufacturing the Grinding tool or tool holder molded at the same time become.

According to an advantageous embodiment of the invention the swivel bearing designed as a ball bearing in which the holder-side polygonal profile bearing pin and is used in the manufacture of the tool holder from plastic together with the one end of the ball bearing partially covering, cap-like washer in the Tool holder injected. The cap-like washer, which still partially overlaps the outer ring of the ball bearing, prevents plastic from spraying above the Ball bearings can flow into this. By injecting of the ball bearing in one piece with the tool holder Spigot is not only a manufacturing advantage, but also the ball bearing is also protected against dust during operation.

According to a preferred embodiment of the invention, the Training of the polygon profiles and the arrangement of the hit the tool-side hook in this way. that the grinding tool in several, preferably three, by the same circumferential angle offset rotary positions around the pivot axis the tool holder can be attached. This makes it possible e.g. as a triangular, symmetrical sanding plate trained grinding tool quickly and precisely opposite rotated by 120 ° to its original position position so that when the grinding effect of the first corner area of the sanding plate and the sanding sheet, e.g. in the event of wear or soiling, the second and third corner area instead of the first or second to other corner loops can be used, the corner always is directed exactly forward.

In a further embodiment of the The tool holder carries the hand grinder on one Pitch circle on the radial outer area of the tool holder facing surface cone-like feet that form-fit in grab suitable recesses of the sanding plate and as Anti-rotation lock of the sanding plate against the Tool holders serve and therefore a very direct Power transmission between the tool holder and the Allow sanding pads.

Since the grinding tool is a wearing part, that is Quick repositioning of the corner areas compared to the Tool holder or the easy interchangeability of the Grinding tool of considerable advantage. This advantage results from the interaction of the locking means of the Grinding tool with those of the tool holder.

The tool holder is also a important component or spare part on which differently designed or equipped grinding tools replace or lockable without auxiliary tools or have it implemented.

drawing

Fig. 1 ausschnittweise eine Seitenansicht einer elektrischen Handschleifmaschine, teilweise geschnitten.

Fig. 2 eine perspektivische Draufsicht eines Werkzeughalters der Handschleifmaschine in Fig. 1.

Fig 3 einen Schnitt längs der Linie III-III in Fig. 2.

Fig. 4 eine Unteransicht des Werkzeughalters in Fig. 2.

Fig. 5 eine perspektivische Unteransicht einer Bedientaste einer Schnellverriegelung an der Handschleifmaschine in Fig. 1, vergrößert dargestellt.

Fig. 6 eine Unteransicht eines ringförmigen Federdrahts der Schnellverriegelung an der Handschleifmaschine in Fig. 1;

Fig. 7 eine Draufsicht eines Schleifwerkzeugs der Handschleifmaschine in Fig. 1 und

Fig. 8 eine räumliche Unteransicht eines weiteren Ausführungsbeispiels des erfindungsgemäßen Werkzeughalters.

The invention is explained in more detail in the following description with reference to an embodiment shown in the drawing. Show it:

Fig. 1 shows a partial side view of an electric hand grinder, partially cut.

FIG. 2 shows a perspective top view of a tool holder of the hand grinding machine in FIG. 1.

3 shows a section along the line III-III in FIG. 2nd

4 is a bottom view of the tool holder in FIG. 2.

Fig. 5 is a perspective bottom view of an operating button of a quick lock on the hand grinder in Fig. 1, shown enlarged.

Fig. 6 is a bottom view of an annular spring wire of the quick lock on the hand grinder in Fig. 1;

Fig. 7 is a plan view of a grinding tool of the hand grinder in Fig. 1 and

8 is a three-dimensional bottom view of a further exemplary embodiment of the tool holder according to the invention.

Description of the embodiment

The detail in Fig. 1 in side view and partially electric hand grinder shown in section as an orbital sander 9 with a triangular, symmetrical grinding plate trained grinding tool 10 designed. The bottom of the made of plastic Sanding plate is with a Velcro covering 11 for receiving provided sanding sheets, not shown. The Orbital sander has a double-shell machine housing, which is composed of two housing shells 121, 122, which along a parallel to the longitudinal axis of the housing Butt joint 123. In the machine housing 12 is an electric motor 13 added, of which only the one on the Output shaft 14 seated fan 15 can be seen. One on the Top of the machine housing 12 arranged in / Switch 16 is used to turn the Electric motor 13. The output shaft 14 drives via Angular gear 17 on a working shaft 18, which in two Ball bearings 19a and 19b fixed to the housing are rotatable is stored and on the lower front of the Machine housing 12 with an eccentric pin 20 from the Machine housing 12 protrudes. Sitting on the eccentric pin 20 the inner ring of another ball bearing is axially immovable 21, which with its outer ring in a bowl-shaped Tool holder 22 is held, in particular injected. The tool holder 22 made of plastic, which is shown in Fig. 2 to 4 shown enlarged in different views is via a vibrating body 23 on the machine housing 12 attached so that when the eccentric pin 20 rotates rotation is prevented and thus only circular Carries out swinging movement. On the tool holder 22 that is Grinding tool 10 by means of corresponding Positive locking elements - as explained in more detail is determined - on the tool holder side or on the tool side are as well as by means of a quick lock 24, which over an operating button 25 is to be operated manually become. The grinding tool 10 lies on one Support surface 37, which is clearly shown by a forward line is highlighted, the bowl-shaped tool holder 22 and closes a dust extraction chamber with the tool holder 22 26 a, on the one hand via suction holes 27 (Fig. 7) in Grinding tool 10 and corresponding, corresponding Holes in the sanding sheets to the side to be machined of a workpiece, not shown, is open and on the other hand via a bellows 28 with a Machine housing 12 extending dust extraction duct 29 in Connection is made to the end of an external suction fan is to be connected.

The tool holder 22 is in perspective in Fig. 2 Top view, in Fig. 4 in bottom view and in Fig. 3 in Longitudinal section along line III-III in Fig. 2 enlarged shown. He carries on his from the grinding tool 10 facing away from a central ring connector 30, which in the oscillating body 23 held in the machine housing 12 is insertable and 30 formed on the ring socket 30 cams 31 is held in a rotationally fixed manner in the oscillating body 23. Coaxial to Ring socket 30 sits on the grinding tool 10 facing bottom of the tool holder 22 an inside Hollow pin 32 in the coaxial, the ball bearing 21st is recorded. The axes of Ring connector 30, pin 32 and ball bearing 21 are in Fig. 1st and 3 shown in dash-dotted lines and designated 33, while the axis of the Working shaft 18 is marked with 34.

On the top, i.e. the orbital sander 9 facing side, are the ring socket 30 with the cams 31 and the pin 32 in one piece with the tool holder 22 and are also molded during the spraying process. The ball bearing 21 is together with the one end of the Ball bearing 21 partially covering, cap-like Washer 35, the outer ring of the ball bearing 21st partially overlaps, during injection molding in the pin 32 injected, the washer 35, the inflow of Prevents plastic in the ball bearing 21.

As can be seen in particular from FIG. 4, the Underside of the tool carrier 22 on the outside of the Pin 32 formed a symmetrical polygon profile 36, the same of three, offset by 120 ° to each other Circular arc sections 361 are composed of three in turn Same circular arc sections 362 offset from one another by 120 ° are connected in the form of axial strips, the arc radius is larger than that of the circular arc sections 361.

As can be seen from Fig. 7, which is a plan view of the Top of the grinding tool 10 shows with which the Grinding tool 10 on the contact surface 37 on the tool holder 22 supports, stands on the top of the grinding tool 10 a sleeve 38 integral with the grinding tool 10 the inside of which has a polygon profile 36 corresponding, negative or hollow polygon profile 39 is formed with circular arc sections 391 and 392, wherein the sections 392 as axial grooves for receiving the through the circular arc sections 362 determine axial strips are designed so that when placing the grinding tool 10 on the support surface 37 on the tool holder 22 the two Interlock polygon profiles 36,39 and that Grinding tool 10 against rotation on the tool holder 22 establish. The two polygon profiles 36, 39 thus represent the fixed holder and tool side mentioned at the beginning, mutually corresponding positive locking elements between tool holder 22 and grinding tool 10.

Due to the angular symmetry of the polygon profiles 36,39 it is possible to grind the tool 10 in three positions rotated 120 ° relative to one another about axis 33 to place on the tool holder 22. The Quick lock 24 places the grinding tool 10 on Tool holder 22 firmly and prevents unwanted Removal of the grinding tool 10 from the pin 32. Die Quick lock 24 has this on the tool side fixed locking elements 40 and thus interacting, owner-defined Locking elements 41.

As can be seen from FIGS. 1 and 7, the tool-side locking elements 40 as one piece the grinding tool 10 integrally formed hook 42, the on a circular line by the same angle of rotation to each other are arranged offset and from which the bearing surface 37 on Tool holder 22 facing top of the grinding tool 10 stand out. The hooks 42 are for the sake of simplicity molded onto the outside of the sleeve 38, the inner jacket the polygon profile 39 carries. The interacting with it holder-side locking elements 41 are from a ring-shaped spring wire 43 is formed, which in FIG. 4 and 6 is shown. The spring wire 43 has one of the Number of hooks 42 on the sleeve 38 corresponding number, here three indentations 431 pointing radially inwards, corresponding to the hook 42 in turn by the same angle of rotation are arranged offset to each other.

As can be seen from FIGS. 3 and 4, it is ring-shaped curved spring wire 43 in outer slots 51 of webs 44 rotatable or with its legs 432, 433 in Guide slot 53 to one side, in Figure 3 in the Drawing levels into it, pivotable on the tool holder 22 recorded on a to the axis 33 of the pin 32 or of the ball bearing 21 coaxial pitch circle are arranged and integrally with the tool holder 22 from this down protrude. The webs 44 are arranged in pairs so that in the locking position of the spring wire 43, as shown in FIG. 4 is shown, a pair of webs on both sides of one Indentation 431 lies. The pairs of bridges are in turn offset from each other by the same circumferential angle. The ring-shaped curved spring wire 43 runs approximately radially in two striving, mutually parallel legs 432 and 433.

One leg 432 is bent at right angles at the end and lies in front of the straight end of leg 433. Die Legs 432, 433 pass through the opening 52 in the front Tip of the tool holder 22.

On the free ends of the legs 432, 433 is the Control button 25 of the quick lock 24 can be clipped on and is thereby carried by the spring wire 43. The Control button 25 on its underside corresponding grooves and Lugs on, as shown in Fig. 5. The Leg 432 of the spring wire 43 (Fig. 6) is in the Groove 45 indented, with its bent end in the Cross groove 47 comes to rest while the other leg 433 is clipped into the groove 46. The grooves 45-47 each assigned locking lugs 48 - 50 ensure a safe Connection between the legs 432.433 and the control button 22. Using the control button 25 can now in the Cross slots 51 of the webs 44 guided spring wire 43 in the Spring wire plane are pivoted, which makes the in Locking position engaging the hook 42 Indentations 431 slide away from the hook 42 so that the parts of the spring wire 43 located radially further outward move the place of the indentations 431 and thus the hooks 42 release. The grinding tool 10 in Manually subtracted from the tool holder 22 in the direction of the axis 33 become. In this position the quick lock 24 can the grinding tool 10 changed and - in the aforementioned Forming the grinding tool 10 as a triangular, symmetrical grinding plate - rotated by 120 ° with one corner forward again in the tool holder 22 become. This will evenly wear the Corner areas of the sanding sheets allows without them must be released from the Velcro coating of the tool holder 22. After inserting the grinding tool 10 by nesting of the two polygon profiles 36, 39 and placing the Grinding tool 10 on the bearing surface 37 of the Tool holder 22, the control button 25 is pivoted back (in Fig. 4 clockwise) until the spring wire 43 the in Fig. 4 takes the locking position shown. The Indentations 431 of the spring wire 43 then engage behind again the hook 42 of the grinding tool 10, and the latter is firmly locked on the tool holder 22. With appropriate Formation of the locking elements 40 on the tool side, e.g. as resilient tongues with the hooks 42 at the free end as well as corresponding elastic design of the spring wire 43 or the indentations 431, the grinding tool 10 on the tool holder 22 are clipped on. The control button 25 can then be omitted as well as the rotatable mounting of the Spring wire 43 in the transverse slots 51 of the webs 44.

The spatial bottom view of another shown in FIG. 8 Embodiment of the tool holder according to the invention In this respect, 222 goes over the exemplary embodiment according to FIG. 4 beyond when there were six down, perpendicular to the Underside or the support surface 237 protruding, has cylindrical, cone-like feet 254 with crowned or chamfered free ends.

The tool holder 222 has a suction channel 229 symmetrical polygon profile 236 with 120 ° each offset, identical circular arc sections 461, 462, webs 244 without inserted spring wire and without Control button and a recess 252 for the passage of the Leg of the spring wire corresponding to FIG. 4.

The feet 254 engage with the support surface 237 projecting area in essentially free of play Guide holes 660 one shown in Figure 9 Sanding discs 100, which except for the guide holes 660 corresponds to Figure 7.

Due to the positive engagement of the feet 254 in the Guide holes 660 of the grinding plate 100 also become the polygon profiles 236, 390 of the tool holder 222 and the Sanding discs 100, which in the sleeve 380, 390 des Grinding plates or grinding tool 100 according to FIG. 9 grip, created an anti-twist device. Through this additional anti-twist protection is a particularly firm one Locking the grinding plate 100 against the Tool holder 222 secured. This will increase the precision of the Guide the sanding plate over the one to be machined Workpiece area improved.

Fig. 9 shows a top view of the top of another Embodiment of the grinding tool 100 that up to Guide holes 660 with the grinding tool 10 according to FIG. 7 matches and for coupling with the tool holder 222 8 is provided.

The grinding tool 100 is supported on the contact surface 237 on the tool holder 222 according to FIG. From the top of the Grinding tool 100 is one with the grinding tool 100 one-piece sleeve 380, on the inside of which the Polygon profile 236 of the tool holder 222 accordingly negative or hollow polygon profile 390 with Circular arc sections 491 and 492 is formed. At the Place the grinding tool 100 on the support surface 370 the two polygon profiles 236 engage on the tool holder 222, 390 interlocking and insert the grinding tool 100 non-rotatable on the tool holder 222. The two Polygon profiles 236, 390 form the holder-side mentioned and determined on the tool side, corresponding to each other Positive locking elements between tool holder 222 and Grinding tool 100.

Claims (11)

1. Electric hand-held sanding machine having an interchangeable, at least partly plate-shaped sanding tool (10), having a tool holder (22) which sits on a rotating eccentric pin (20) with a rotary bearing (21) in between and on whose underside facing away from the machine bearing surfaces (37) for the sanding tool (10) are formed, and having a quick-acting locking means (24) which has locking elements (40, 41) which are secured on the tool side and the tool-holder side, correspond with one another and are intended for securing the sanding tool (10) to the tool holder (22), characterized in that hooks (42) which are arranged on a circular line and preferably project from the top side, facing the tool holder (22), of the sanding tool (10) serve as tool-side locking elements (40), and in that a spring wire (43) which is bent in a ring shape and is arranged such that the hooks (42) can engage behind it serves as tool-holder-side locking element (41).
2. Hand-held sanding machine according to Claim 1, characterized in that the spring wire (43) is held on the tool holder (22) so as to be pivotable in a plane parallel to the bearing surface (37) on the tool holder (22) and is connected to an operating button (25), and in that the spring wire (43) has a number of radial deformations, preferably niches (431) pointing radially inwards, which essentially correspond to the number of tool-side hooks (42) and which engage behind the tool-side hooks (42) in one pivoted position of the spring wire (43), this pivoted position forming the locking position for the sanding tool (10), and release the hooks (42) in another pivoted position of the spring wire (43).
3. Hand-held sanding machine according to Claim 1 or 2, characterized in that the spring wire (43) is accommodated on the tool holder (22) in a displaceable manner in transverse slots (51) of webs (44) which are arranged on a pitch circle coaxial to the rotary-bearing axis (33) and are preferably formed in one piece with the tool holder (22), in that in each case a web pair lies on both sides of one of the niches (431) in the locking position of the spring wire (43), and in that the web pairs are offset from one another, preferably by the same circumferential angles.
4. Hand-held sanding machine according to one of Claims 1 to 3, characterized in that the annular spring wire (43) ends in two legs (432, 433) which project radially and are parallel to one another and of which one leg (432) is bent at right angles at the free end in front of the other leg (433), and in that the operating button (25) is clipped onto the two legs (432, 433) at their free end.
5. Hand-held sanding machine according to one of Claims 1 to 4, characterized in that tool-side and tool-holder-side positive-locking elements are realized by polygonal profiles (36, 39) which engage axially one inside the other and are arranged coaxially to the rotary-bearing axis (33) on sides of tool holder (22) and sanding tool (10) which face one another.
6. Hand-held sanding machine according to Claim 5, characterized in that the tool-side polygonal profile (39) is formed on the inside of a sleeve (38) projecting from the top side of the sanding tool (10) and preferably in one piece with the latter, and the holder-side polygonal profile (36) is formed on the underside of a stem (32) which projects from the tool holder (22), is preferably in one piece with the latter and can be inserted into the sleeve (38) in a positive-locking manner, and in that the hooks (42), forming the tool-side locking elements (40), of the quick-acting locking means (24) are integrally formed in one piece, in a radially projecting manner, on the outside of the sleeve (38).
7. Hand-held sanding machine according to Claim 5 or 6, characterized in that the polygonal profiles (36, 39) are designed in such a way and the tool-side hooks (42) are arranged in such a way that the sanding tool (10) can be attached to the tool holder (22) in a plurality of rotary positions, preferably three rotary positions, offset from one another by the same circumferential angles, about the rotary-bearing axis (33).
8. Hand-held sanding machine according to Claim 6 or 7, characterized in that the rotary bearing, designed as a ball bearing (21), is arranged in the stem (32) and, when the plastic tool holder (22) is being produced, is incorporated in the tool holder (22) during injection moulding together with a cap-like annular disc (35) partly covering an end face of the ball bearing (21).
9. Hand-held sanding machine according to Claim 8, characterized in that the tool holder (222) carries feet (254) which, as additional anti-rotation locking for the sanding plate (100) relative to the tool holder (222), can engage in the sanding plate (100) in a positive-locking manner.
10. Sanding tool designed in particular as a sanding plate and intended for mounting on a tool holder (22) of a hand-held sanding machine, characterized by a preferably symmetrical polygonal profile (39), arranged on its side facing the tool holder (22), having rotary driving engagement in a corresponding polygonal profile (36) of the tool holder (22), the polygonal profile (39) carrying radially projecting hooks (42) for securing axially to the tool holder (22).
11. Sanding tool according to Claim 10, characterized in that it has guide holes (660) for the engagement of the feet (254) of the tool holder (222).

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