EP2286959A2 - Scrubbing-grinding tool - Google Patents

Abstract

The tool has a support plate (1) that is formed concentric to a centre longitudinal axis (7). The support plate exhibits a centre opening (3) for receiving a drive shaft of a drive machine. A fiber grinding disk (9) is formed from a fiber disk (10) with a resin-bound abrasive lining (11). The fiber grinding disk exhibits an outer annular grinding region (8) that is arranged radial to the centre longitudinal axis. The fiber grinding disk is supported or glued to the support plate using an adhesive layer (12), where the disk exhibits a grinding side (4) and made of vulcanized fiber.

Description

• mit einem Tragteller, der
  • - konzentrisch zu einer Mittel-Längs-Achse ausgebildet ist und
  • - eine mittlere Öffnung zur Aufnahme einer Antriebswelle einer Antriebsmaschine aufweist,
  und
• mit einer Fiber-Schleifscheibe, die
  • - aus einer Fiber-Scheibe, mit einem harzgebundenen Schleifmittel-Belag gebildet ist,
  • - einen radial zur Mittel-Längs-Achse angeordneten, äußeren ringförmigen Schleif-Bereich aufweist,
  • - sich auf dem Tragteller abstützt und
  • - eine Schleifseite aufweist,

The invention relates to a roughing-grinding tool

• with a carrier plate, the
  • - Is formed concentrically to a central longitudinal axis and
  • - Has a central opening for receiving a drive shaft of a prime mover,
  and
• with a fiber grinding wheel that
  • - made of a fiber disc, with a resin-bonded abrasive coating,
  • having an outer annular grinding area arranged radially to the central longitudinal axis,
  • - is supported on the support plate and
  • has a grinding side,

Such roughing-grinding tools are known in practice in large numbers. Such fiber grinding wheels are flexible and releasably mounted on the support plate. The mounting on the support plate is done by a screw-on flange in the Kröpfungsbereich the fiber grinding wheel. For work in which uniform surface structures on the workpiece to be machined must be achieved by means of the roughing and grinding tool, the service life of the fiber grinding wheel is short, for example only about 1 minute. After this time, the abrasive grain of the fiber abrasive disc shows its first signs of wear, whereby the surface of the workpiece to be machined is no longer completely uniform. The fiber grinding wheel is therefore already replaced after this time.

In order to enable a quick replacement of such fiber grinding wheels, a quick-change system has been developed, as in the EP 1 741 515 B1 is shown and described. For the mentioned application fine-grained abrasive grain is used. These fine grains result in a high heat load on the workpiece during grinding. If the material to be ground, for example, is stainless steel or has a low thermal conductivity, tarnish occurs. For this reason, in the aforementioned quick-change system according to the EP 1 741 515 B1 Cooling channels provided in the support plate to achieve a good cooling of the grinding wheel.

If grinding wheels with coarse abrasive are used for rough grinding, as is customary in practice, there is a risk that the backing bearing the abrasive material will break. This is especially true when serving as a base for the abrasive serving discs of little solid material.

From the EP 0 750 539 B1 (corresponding DE 695 06 851 T2 ) and the EP 0 617 652 B1 (corresponding DE 692 28 760 T2 ) Abrasive base are known, as they are common practice, which thus consist of a serving as a support or underlay elastically flexible disc on which an abrasive grain is attached by means of a synthetic resin.

From the DE 10 2006 010 366 B3 and the DE 90 17 256 U1 So-called flap discs are known in which the abrasive blades are glued in the usual way to a carrier.

The invention has for its object to design a roughing-grinding tool of the generic type so that it has a long service life with simple and inexpensive construction.

This object is achieved in a roughing-grinding tool of the generic type in that the fiber abrasive disc is adhered to the support plate. By sticking the fiber grinding wheel on the support plate has surprisingly revealed that a ripping of the fiber grinding wheel does not occur despite the high loads during rough grinding. This can be explained by the fact that torque occurring during rough grinding does not have to be completely absorbed by the fibers of the fiber disk. There is considerable transfer to the carrier plate. Even with torque overload and when abutting the outer edge of the fiber grinding wheel to a workpiece, it does not break the fiber grinding wheel. So there are no smaller or larger segments of the fiber grinding disc, so that injury to the user are largely excluded.

The fiber disc is made of vulcanized fiber, a material that has been known for a century and a half and made from cotton fibers. Surprisingly, it has also been found that the roughing and grinding tool is far superior to conventional roughing wheels both in terms of machined mass per unit time and overall machinable mass. This is especially true when Ceramic grain is used as an abrasive.

It has proven particularly advantageous if the grinding wheel with the abrasive coating is slightly convexly curved towards the grinding side. There Such rough grinding wheels, so roughing-grinding tools are used on hand-held grinding machines, an exact angular position of the grinding tool against the surface to be ground is usually not observed when using. The slight curvature causes no high local surface pressures between the grinding wheel and the workpiece to be machined, with the result of a corresponding tearing of abrasive grain occur. This leads to a considerable increase in the service life or the cutting performance. Further, when the grinding portion is divided into a main grinding portion and a radially outer smaller outer grinding portion, with the outer grinding portion being curved more toward the back of the grinding tool, the risk of the grinding tool is increased Removal of the grinding wheel from the carrier plate further reduced. In addition, the grinding tool can hereby also be used for a short time for face grinding.

The further subclaims give advantageous developments again.

Fig. 1

eine erste Ausführungsform eines Schrupp-Schleif- Werkzeugs gemäß der Erfindung in einer Rück-Ansicht ge- mäß dem Sichtpfeil I in Fig. 3,

Fig. 2

eine Draufsicht auf die Schleifseite des Schrupp-Schleif- Werkzeugs gemäß dem Sichtpfeil II in Fig. 3,

Fig. 3

einen Querschnitt durch das Schrupp-Schleif-Werkzeug ge- mäß der Schnittlinie III-III in Fig. 1,

Fig. 4

einen Querschnitt durch eine zweite Ausführungsform eines Schrupp-Schleif-Werkzeugs gemäß der Erfindung,

Fig. 5

einen Querschnitt durch eine dritte Ausführungsform eines Schrupp-Schleif-Werkzeugs gemäß der Erfindung und

Fig. 6

eine Hand-Schleifmaschine mit einem Schrupp-Schleif- Werkzeug nach der Erfindung im Schleifeinsatz.

Further features, advantages and details of the invention will become apparent from the following description of exemplary embodiments with reference to the drawing. It shows

Fig. 1

a first embodiment of a roughing-grinding tool according to the invention in a rear view according to the viewing arrow I in Fig. 3 .

Fig. 2

a plan view of the grinding side of the roughing-grinding tool according to the viewing arrow II in Fig. 3 .

Fig. 3

a cross section through the roughing-grinding tool according to the section line III-III in Fig. 1 .

Fig. 4

a cross section through a second embodiment of a roughing-grinding tool according to the invention,

Fig. 5

a cross-section through a third embodiment of a roughing-grinding tool according to the invention and

Fig. 6

a hand grinder with a roughing-grinding tool according to the invention in the grinding insert.

That in the FIGS. 1 to 3 illustrated roughing-grinding tool has a in the usual way from impregnated with phenolic resin and compressed glass fibers existing support plate 1, which has a flat, annular clamping area 2 in the usual way, in which a likewise circular opening 3 for receiving a drive shaft Drive machine is formed. The annular clamping region 2 surrounding the opening 3 is provided with a metal ring 5 on the rear side of the support plate 1 remote from a grinding side 4. The clamping area 2 is adjoined by a cranking area 6, which is likewise of annular design and rises radially to the axis 7 of the carrier plate 1 towards the grinding side 4. The cranking region 6 is adjoined by an annular grinding region 8, which is inclined radially outward from the grinding side 4, counter to the cranking region 6, radially to the axis 7. This embodiment of a support plate 1 is well known and common.

On the grinding side 4, a fiber grinding wheel 9 is attached. This is a so-called abrasive on a base, which consists of a fiber disk 10 as a support or base and a resin-bonded abrasive coating 11. The fiber disk 10 is made of vulcanized fiber, which is a bound, pressed material based on cotton fibers. The abrasive coating 11 is formed by ceramic grain 11.1, which is produced from a microgranulate by sintering. The microgranules break individually from the respective grain, so that thereby the stability of the ceramic grain 11.1 is significantly increased compared to conventional abrasives. The resin bonded abrasive pad 11 is bonded to the fiber disk 10 in the usual manner. The fiber disk 10 of the fiber grinding wheel 9 is connected to the grinding side 4 of the support plate 1 by means of an adhesive layer 12.

$$\mathrm{R}\mathrm{9}\mathrm{=}\mathrm{R}\mathrm{8}$$

The radius R1 of the support plate 1 is - like FIG. 1 can be removed - slightly smaller than the radius R9 of the fiber grinding wheel 9, without the fiber grinding wheel 9 projecting radially to the axis 7 on the outer edge 13 of the support plate 1. The cranking region 6 has a radius R6 from the axis 7 at the transition to the main grinding region 8. The main grinding portion 8 has a radius R8 from the axis 7 which is equal to the radius R9 of the fiber grinding disc 9. For the radii R6 and R8 with respect to the radius R9, the following applies: $$\mathrm{0}\mathrm{.}\mathrm{45}\mathrm{R}\mathrm{9}\mathrm{\le }\mathrm{R}\mathrm{6}\mathrm{\le }\mathrm{0}\mathrm{.}\mathrm{7}\mathrm{R}\mathrm{9}$$

$$\mathrm{R}\mathrm{9}\mathrm{=}\mathrm{R}\mathrm{8th}$$

The use of the grinding tool takes place in the usual manner at an angle to the axis 7.

As far as in the second embodiment according to FIG. 4 the same or similar parts or regions are present as in the embodiment according to the FIGS. 1 to 3 , the same reference numbers are used with a prime. The support plate 1 'consists of a glass cloth impregnated with epoxy resin. He has - as in the embodiment of the FIGS. 1 to 3 - a constant thickness h. The planar annular clamping area 2 'is likewise formed with a circular opening 3' for receiving a drive shaft of a drive machine. The annular clamping region 2 'surrounding the opening 3' is not reinforced with a metal ring in this exemplary embodiment. The curvature region 6 'adjoining the clamping region 2' is likewise of annular design and rises radially to the axis 7 'of the carrier plate 1' towards the grinding side 4 '. The planar clamping region 2 'merges with a radius of curvature r2' in the cranking region 6 '. The cranking region 6 'is adjoined in turn by an annular main grinding region 8', which extends radially to the axis 7 'against the cranking region 6', namely radially to the axis 7 'outwardly from the grinding side 4' is inclined. Seen from the axis 7 'to the outside of the grinding area 8' so from the grinding side 4 'inclined away. Also in the design FIG. 4 is on the grinding side 4 'of the support plate 1' a fiber grinding disc 9 'attached. This is also a so-called abrasive on a base, which consists of a fiber disk 10 'as a support or base and a resin-bonded abrasive coating 11'. The fiber grinding wheel 9 'is thus a self-contained grinding wheel, which could be used, as described above for the prior art according to EP 1 741 515 B1 has been described. It is flexible, so flexible. The structure of the fiber grinding wheel 9 'corresponds to the above to the FIGS. 1 to 3 already described. The abrasive coating 11 'thus has ceramic grain 11.1'. Also in the execution after FIG. 4 is the fiber slice 10 'of the fiber abrasive disc 9' connected to the support plate 1 'by means of an adhesive layer 12'.

As FIG. 4 can be removed, the cranking region 6 'is in the grinding area 8' with a radius of curvature r6 'on. The main grinding area 8 'itself is also curved, slightly convex to the grinding side 4' with a radius of curvature r8 '.

The outer grinding area 15 'adjoining the main grinding area 8' is inclined radially outward away from the grinding side 4 'and convexly curved toward the grinding side 4' with a radius of curvature r15 '.

• 15 mm ≤ r2' ≤ 30 mm und bevorzugt 20 mm ≤ r2' ≤ 25 mm
• 15 mm ≤ r6' ≤ 40 mm und bevorzugt 15 mm ≤ r6' ≤ 20 mm
• 190 mm ≤ r8' ≤ 300 mm und bevorzugt 200 mm ≤ r8' ≤ 250 mm
• 17 mm ≤ r15' ≤ 40 mm und bevorzugt 15 mm ≤ r15' ≤ 20 mm

The curvatures with the radii of curvature r6 ', r8' and r15 'are formed convex to the grinding side 4'; the reason for this is that the use of the roughing and grinding tool takes place in the usual way at an angle to the axis 7 '. The fiber disc 10 'ends - as FIG. 4 is removable - flush with the outer edge 13 'of the support plate 1'. The following relationships apply for the radii of curvature r2 ', r6', r8 'and r15':

• 15 mm ≤ r2 '≤ 30 mm and preferably 20 mm ≤ r2' ≤ 25 mm
• 15 mm ≤ r6 '≤ 40 mm and preferably 15 mm ≤ r6' ≤ 20 mm
• 190 mm ≤ r8 '≤ 300 mm and preferably 200 mm ≤ r8' ≤ 250 mm
• 17 mm ≤ r15 '≤ 40 mm and preferably 15 mm ≤ r15' ≤ 20 mm

$$\mathrm{0}\mathrm{,}\mathrm{75}\mathrm{R}\mathrm{9}\mathrm{ʹ}\mathrm{\le }\mathrm{R}\mathrm{8}\mathrm{ʹ}\mathrm{\le }\mathrm{R}\mathrm{9}\mathrm{ʹ}$$

The fiber abrasive disc 9 'has a radius R9' from the axis 7 '. The offset area 6 'has a radius R6' from the axis 7 'at the transition to the main grinding area 8'. The main grinding area 8 'has a radius R8' from the axis 7 'which is equal to the radius only R9 'of the fiber abrasive disc 9' is when there is no separate more curved outer abrasive region 15 '. For the radii R6 'and R8' with respect to the radius R9 ', the following applies: $$\mathrm{0}\mathrm{.}\mathrm{45}\mathrm{R}\mathrm{9}\text{'}\mathrm{\le }\mathrm{R}\mathrm{6}\text{'}\mathrm{\le }\mathrm{0}\mathrm{.}\mathrm{7}\mathrm{R}\mathrm{9}\text{'}$$

$$\mathrm{0}\mathrm{.}\mathrm{75}\mathrm{R}\mathrm{9}\mathrm{\text{'}}\mathrm{\le }\mathrm{R}\mathrm{8th}\mathrm{\text{'}}\mathrm{\le }\mathrm{R}\mathrm{9}\mathrm{\text{'}}$$

The embodiment according to FIG. 5 is different from that FIG. 4 in that the support plate 1 "has a radially outwardly increasing elasticity, that is to say a lower rigidity or greater flexibility FIG. 4 Matching parts or areas are therefore designated by the same reference numerals and all similar parts or areas with the same reference numerals as to FIG. 4 have been used, supplemented by a double-dashed line, without requiring a new description.

The increasing elasticity of the support plate 1 "in the direction of the outer edge 13" is achieved in that the support plate 1 "has a plurality of respectively annular sections 16, 17 and 18, which have a different, radially outwardly decreasing thickness FIG. 5 the section 16 extends approximately as far as the transition from the cranking area 6 'into the main grinding area 8 ", here it has the thickness h, the annular section 17 extending radially outward extending radially to the outside. Grinding range 15 ". The portion 17 has a thickness h '; the outer portion 18 has a thickness h ", where h> h '>h". Basically, according to a graduated embodiment FIG. 5 assume that there are at least two such sections and no more than five such sections are. For the radii R6 ', R8 "and R9', the above relationships apply.

Out FIG. 6 the use of the roughing-grinding tool according to the invention on manual grinding machines 19 emerges. The roughing-grinding tool is mounted on an output shaft 20 of the hand grinder 19, which is inserted through the opening 3 of the grinding tool, so that the axis 7 coincides with the central axis of the output shaft 20. The attachment of the grinding tool on the output shaft 20 by means of a clamping nut 21st

Due to the convex curvature of the main grinding area 8 "towards the grinding side 4 ', it is achieved that during surface grinding of workpieces 22, ie in the main field of application of such grinding tools, even in the case of the unavoidable pendulum movements of the grinding tool, a uniform loading of the abrasive This results in less wear and tear on these grinding / grinding tools, which are always used on hand-held grinders, resulting in a longer service life and a higher removal rate of the grinding wheel reinforced by the outwardly increasing elasticity of the grinding tool according to FIG. 5 ,

The stronger curvature in the outer grinding area 15 'or 15 "causes when abutting the outer edge 13' or 13" of the grinding wheel to an object no detachment of the fiber grinding wheel 9 'together with abrasive coating 11 from the support plate. 1 'or 1 "takes place.

Claims (13)

Rough grinding tool - With a support plate (1, 1 ', 1 "), the - - Concentric to a central longitudinal axis (7, 7 ') is formed and - - Has a central opening (3, 3 ') for receiving a drive shaft of a drive machine, and - with a fiber grinding wheel (9, 9 ', 9 "), the - - is formed from a fiber disc (10, 10 '), with a resin-bonded abrasive coating (11, 11'), - - a radially to the central longitudinal axis (7, 7 ') arranged, outer annular grinding area (8, 8', 8 "), - - on the support plate (1, 1 ', 1 ") is supported and - - has a grinding side (4, 4 '), characterized,
that the fiber grinding wheel (9, 9 ', 9 ")
is glued to the support plate (1, 1 ', 1 "). Rough grinding tool according to claim 1, characterized in that
that the fiber grinding disc (9, 9 ', 9 ") by means of an adhesive layer (12, 12') on the support plate (1, 1 ', 1") is glued. Rough grinding tool according to claim 1 or 2, characterized by ceramic grain (11.1, 11.1 ') as an abrasive. Rough grinding tool according to one of claims 1 to 3, characterized
in that the grinding area (8 ', 8 ") is designed to be convex with a radius of curvature r8' towards the grinding side (4 '). Rough grinding tool according to one of claims 1 to 4, characterized
in that the grinding area has a main grinding area (8 ', 8 ") and an outer grinding area (15', 15") which adjoins the axis (7 ') outwards radially and which faces the grinding side (4 ') is convexly formed with a radius of curvature r15'. Rough grinding tool according to claim 4 and 5, characterized
that applies to the radius of curvature r15 'in relation to the radius of curvature r8': r15 '' r8 '. Rough grinding tool according to claim 4, characterized in that
that 'applies: 190 mm ≤ r8' for the radius of curvature r8 ≤ 300 mm and preferably 200 mm ≤ r8 '≤ 250 mm. Rough grinding tool according to claim 5, characterized in that
that 'is true: 17 mm ≤ r15' for the radius of curvature r15 ≤ 40 mm and preferably 15 mm ≤ r15 '≤ 20 mm. Rough grinding tool according to one of claims 1 to 8, characterized
in that the grinding region (8 ', 8 ") has an inner radius R6' and an outer radius R8 'and the fiber-abrasive disc (9') has an outer radius R9 ', where: $$\mathrm{0}\mathrm{.}\mathrm{45}\mathrm{R}\mathrm{9}\text{'}\mathrm{\le }\mathrm{R}\mathrm{6}\text{'}\mathrm{\le }\mathrm{0}\mathrm{.}\mathrm{7}\mathrm{R}\mathrm{9}\text{'}$$

and $$\mathrm{0}\mathrm{.}\mathrm{75}\mathrm{R}\mathrm{9}\mathrm{\text{'}}\mathrm{\le }\mathrm{R}\mathrm{8th}\mathrm{\text{'}}\mathrm{\le }\mathrm{R}\mathrm{9}\mathrm{\text{'}}$$

Rough grinding tool according to one of claims 1 to 9, characterized
that the supporting plate (1 ") radially to the axis (7 ') has an outwardly increasing elasticity. Rough grinding tool according to claim 10, characterized in that
that the elasticity gradually increases radially outward. Rough grinding tool according to claim 11, characterized in that
in that the support plate (1 ") has a plurality of annular sections (16, 17, 18) each having a thickness h, h ', h" which decreases radially outwards relative to the axis (7'). Rough grinding tool according to one of claims 1 to 12, characterized
that the fiber disc (10, 10 ') is made of vulcanized fiber.

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