AU2008356428B2

AU2008356428B2 - Roughing grinding wheel

Info

Publication number: AU2008356428B2
Application number: AU2008356428A
Authority: AU
Inventors: Markus Bernhardt; Frank Henn; Martin Wordehoff
Original assignee: August Rueggeberg GmbH and Co KG
Current assignee: August Rueggeberg GmbH and Co KG
Priority date: 2008-05-16
Filing date: 2008-11-03
Publication date: 2014-08-21
Anticipated expiration: 2028-11-03
Also published as: WO2009138114A1; PL2265410T3; CN102026777A; EP2265410A1; AU2008356428A1; ES2380282T3; ATE548159T1; EP2265410B1; CN102026777B; US20110065369A1; DE102008023946B3

Abstract

A roughing grinding wheel (1) comprises a plurality of index plates (8), which are level in design, are disposed closely on top of each other in an outer work region (13) without being connected and without being laminated, are tightly connected to each other in an inner connecting region located inside the work region (13), and in a center opening (3) are provided with a hub (4) extending through the grinding wheel (1).

Description

Roughing-grinding disc The invention relates to a roughing-grinding disc. 5 A relatively thick peripheral grinding disc is known to the applicant, which consists of a plurality of individual discs which are glued to one another all over and reinforced with woven fabric, it being possible for an elastic insert to be provided in the adhesive layer. Multi-section discs of this type have a higher grinding output than a compact disc constructed in one piece. A compact disc is moreover known to the applicant, which, in its radial outer regions, in each 10 case, has grinding medium-free zones, which are formed by annular intermediate layers, which can optionally be removed again, so a clear gap is formed between the adjacent regions. These grinding medium-free zones, during peripheral grinding, lead to particularly cool grinding and moreover produce still further chip space, which allows a substantial increase in the grinding output with a disc composition which is otherwise identical. 15 A roughing-grinding disc is known to the applicant, the diameter of which is greater by at least a factor of 10 than its thickness. Roughing-grinding discs of this type are used on hand-held, pneumatically or electrically driven angle grinding machines. Strong vibrations occur here during grinding use and can cause significant physical damage to the hand-arm system of the 20 user. To reduce vibrations of this type, an annular separating layer is arranged between individual layers in an outer working region, in each case. Within this working region, it has a compact structure. The separating layer primarily has the function of reducing the amplitude of the vibration during grinding. C:po\WAord\SPEC-9O0537doc 2 The above discussion of background art is included to explain the context of the present invention. It is not to be taken as an admission that any of the documents or other material referred to was published, known or part of the common general knowledge in Australia at the priority date of any one of the claims of this 5 specification. A desirable outcome of the present invention is to provide an improved vibration damped roughing-grinding disc for hand-held use, which is particularly simple with regard to its structure and can therefore be produced particularly simply. 10 Throughout the description and claims of this specification, the word "comprise" and variations of that word, such as "comprising" and "comprises" are not intended to exclude other additives, steps or integers. 15 The invention is based on the aspect of providing a vibration-damped roughing grinding disc for hand-held use, which is particularly simple with regard to its structure and can therefore be produced particularly simply. This aspect is achieved according to the invention by a roughing-grinding disc, 20 consisting of a plurality of individual part discs, which have a common axis, - have grinding grain bound with synthetic resin and reinforcements, - have an external diameter D, and - are connected to one another by means of an adhesive layer, wherein the part discs are configured planar, and the reinforcements are provided 25 on the respective outer sides of the part discs with respect to the axis, and wherein the grinding grain bound with synthetic resin is provided between the reinforcements of each part disc, the part discs being located closely against one another, unconnected and uncovered, in a radially outer working region with respect to the axis , 30 wherein the part discs are connected to one another in a radially inner connecting region with respect to the axis located within the outer working region, with a 2a diameter d by means of the adhesive layer , and wherein the part discs are provided in a centre opening with a hub passing through the grinding disc.

-3 Fig. I shows a hand-grinding machine with a roughing-grinding disc according to the invention in grinding use, Fig. 2 shows a roughing-grinding disc according to the invention in 5 a perspective view, Fig. 3 shows the roughing-grinding disc according to the invention in an exploded view before assembly, 10 Fig. 4 shows a part disc of a roughing-grinding disc according to the invention in a side view and Fig. 5 shows a roughing-grinding disc assembled on the output shaft of a hand-grinding machine according to the invention in a 15 side view. As emerges from Fig. I and 5, roughing-grinding discs 1 are used on hand-grinding machines 2, specifically so-called angle-grinding machines. The grinding disc 1, for this purpose, has a centre opening 3, in which a 20 hub 4 is inserted. This hub 4 has an internal thread 5, by means of which the grinding disc I is screwed onto an output shaft 7, which is provided with an external thread 6, of the grinding machine 2. The grinding disc 1, in its basic structure, consists of a plurality, and spe 25 cifically two to ten, thin part discs 8 with an external diameter D. Each part disc 8, at its two outer sides, in each case has a reinforcement 9, 10, grind ing grain 11, bound with binding means, generally phenolic resin, being arranged between the two reinforcements 9, 10. The reinforcements 9, 10 consist of a woven fabric impregnated with the binding agent of the grind- -4 ing grain 11, generally a glass fabric. These part discs 8 are hardened. The part discs 8, on their outsides, in other words on the exposed faces of the reinforcements 9, 10, have no labels or paper layers or the like, in other words are uncovered. 5 To produce a roughing-grinding disc 1, a plurality of flat part discs 8 are stacked one above the other, an adhesive layer 12, generally duromers, be ing applied in an annular region around the centre opening 3. This adhesive layer 12 with a diameter d is in each case so thin that when the package 10 consisting of a plurality of part discs 8 is pressed to form a roughing grinding disc 1, the adhesive is absorbed in the surface roughness of the part discs 8 located on one another. This results in the fact that the part discs 8 are rigidly connected to one another in the region of the adhesive layer 12 with the diameter d, and that they are not connected to one another 15 outside the respective adhesive layer 12, but are located closely against one another. "Located closely against one another" does not mean in this con text that adjacent grinding discs 1 have a spacing here of precisely 0, but that no practically relevant air gap exists between two adjacent part discs 8. Thus, with regard to the thickness a of a grinding disc 1 made of n part 20 discs 8 with a thickness b there thus applies: a z n x b. With regard to the thickness b of the part discs 8 there applies: 0.8 mm < b < 1.4 mm. With regard to the ratio of the diameter d of the adhesive layer 12 to the external diameter D of the grinding disc 1 there applies: 0.2 < d/D < 0.65. With re gard to the external diameter D there applies: 10 mm < D < 300 mm. The 25 region, in which the adjacent part discs 8 are not connected to one another, forms the working region 13 of the grinding disc: 1. The hub 4 passes through the centre opening 3 of the grinding disc I on one side, and specifically on the side remote from the grinding machine 2, -5 only slightly with a beaded edge 14, so the roughing-grinding disc 1, al though it is not bent, but is completely flat in design, can be used obliquely as a roughing grinding disc 1, in other words in the manner described at the outset and shown in Fig. 1. However, a surface grind is also possible, in 5 which the roughing-grinding disc I is used with its end face 15 associated with the edge 14 of the hub flat or virtually flat on a workpiece 16. If the roughing-grinding disc 1 is used obliquely in accordance with the view in Fig. 1, this takes place at an angle a between the axis 17 of the disc 1 and therefore also the output shaft 7 of the grinding machine 2 relative to a ver 10 tical 18 to the surface 19 to be ground of the workpiece 16. With regard to the angle a there applies: 20 < a < 600. If, on the other hand, in the man ner mentioned, grinding takes place in a flat manner, with regard to the angle a there applies: a ~ 0'.

Claims

1. Roughing-grinding disc, consisting of a plurality of individual part discs, which 5 - have a common axis, - have grinding grain bound with synthetic resin and reinforcements, - have an external diameter D, and - are connected to one another by means of an adhesive layer, wherein 10 the part discs are configured planar, and the reinforcements are provided on the respective outer sides of the part discs with respect to the axis, and wherein the grinding grain bound with synthetic resin is provided between the reinforcements of each part disc, 15 the part discs being located closely against one another, unconnected and uncovered, in a radially outer working region with respect to the axis, wherein the part discs are connected to one another in a radially inner connecting region with respect to the axis located within the outer 20 working region, with a diameter d by means of the adhesive layer, and wherein the part discs are provided in a centre opening with a hub passing through the grinding disc.

2. Roughing-grinding disc according to claim 1, wherein, the hub only 25 has one beaded edge on an end face of the roughing-grinding disc.

3. Roughing-grinding disc according to any one of claims 1 to 2, wherein -7 the part discs have a thickness b, to which there applies: 0.8 mm < b < 1.4 mm.

4. Roughing-grinding disc according to any one of claims 1 to 3, 5 wherein with regard to the number n of part discs there applies: 2 < n < 10.

5. Roughing-grinding disc according to any one of claims 1 to 4, wherein 10 with regard to the ratio of the diameter d of the inner connecting region to the external diameter D of the part discs there applies: 0.2 < d/D < 0.65.

6. Roughing-grinding disc according to any one of claims 1 to 5, 15 wherein with regard to the external diameter D of the part discs there applies: 100 mm < D < 300 mm.

7. Roughing-grinding disc according to any one of claims 1 to 6, 20 wherein the hub is provided with an internal thread for screwing onto an external thread of an output shaft of a grinding machine.

8. Roughing-grinding disc, comprising a plurality of part discs, 25 substantially as herein described with reference to the accompanying drawings.