ABRASIVE FLAP DISC

Abstract

The abrasive unit contains a carrying disc (A) with a hub (1) set off in the central zone, having a coaxial hole (2) reinforced with a steel flange sleeve (3) for mounting the abrasive unit on the spindle of the angular hand grinder. The lower edges of numerous abrasive flaps (B) are fixed with glue binders (5) on the ring surface of the near-edge zone (4), the abrasive flaps subsequently overlapping one another in the circumferential direction so that their rear edges are exposed. The wheel of the carrying disc (A) is a layered polymer composite with reinforcement consisting of at least two meshes of glass fibre situated on both frontal surfaces of the carrying disc (A). The meshes are bonded by a composite matrix containing a binder of a thermosetting synthetic resin, a fine-grained material in the form of inorganic, mineral or synthetic loose material, particularly quartz, calcareous, carbonaceous or polymineral sand, industrial or quarry dusts, blast furnace or copper slag, or a mixture of the aforementioned materials and for which the natural or crumbled grain size ranges from 0.06 to 2.0 mm and the hardness according to the Mohs scale ranges from 3 to 7.

Claims

1. Abrasive flap disc, containing a carrying disc (A) in a form of a round wheel with a hub (1) which is set off in the central zone and has a coaxial hole (2) reinforced with a steel flange sleeve (3) for mounting the abrasive unit on a grinder spindle, and where lower edges of numerous abrasive flaps (B) are fixed in regular angular spacings with glue binders (5) to the carrying disc (A) on its frontal ring surface of the near-edge zone (4) more distant from the hub (1), the abrasive flaps subsequently overlapping one another in the circumferential direction so that their rear edges are exposed, whereby the wheel of the carrying disc (A) is a layered polymer composite with structural reinforcement consisting of at least two meshes of glass fibre (7p,7) which are situated on both frontal surfaces of the carrying disc (A) and which are bonded by a composite matrix (6) containing a binder of a thermosetting synthetic resin and a fine-grained material, all the components of the layered composite being interconnected in the thermal-pressure process, characterised in that the fine-grained material of the composite matrix (6) is an inorganic, mineral or synthetic loose material, particularly quartz, calcareous or carbonaceous sands or polymineral sand, industrial or quarry dusts, blast furnace or copper slag, or a mixture of the aforementioned materials, whereby their natural or crumbled grain size values range from 0.06 to 2.0 mm and the hardness according to the Mohs scale ranges from 3 to 7.

2. The flap abrasive unit according to claim 1, characterised in that the composite matrix (6) of the carrying disc (A) contains 50 to 95% of fine-grained material and 5 to 50% of synthetic, particularly epoxy or polymer, resin and conditioning additives in the amount ranging from 0 to 45%, especially black or yellow pyrite, barite, calcium carbonate, zinc sulphide and potassium fluoroborate.

3. The flap abrasive unit according to claim 1, characterised in that a mesh of glass fibre with paper glued (7p) to it is moulded into the upper frontal surface and bonded through the inner layer of the composite matrix (6) with a bare mesh of fibre glass (7) moulded into the lower frontal surface under the abrasive flaps (B).

4. The flap abrasive unit according to claim 3, characterised in that both meshes (7p, 7) moulded into the frontal surfaces are adjoined from the inner side by bare meshes of fibre glass (7).

5. The flap abrasive unit according to claim 4, characterised in that in the inner layer of the composite matrix (6) there is moulded at least one bare mesh of fibre glass (7), separated on both sides from the adjacent ones by layers of the composite matrix (6).

Description

[0013] The abrasive flap disc consists of two elements: a carrying disc A and a set of abrasive flaps B. The carrying disc A has a form of a round disc with a hub 1 which is set off in the central zone and in which a coaxial hole 2 is made, encased within a steel flange sleeve 3 designed for mounting the abrasive unit on the angular grinder spindle. On the frontal surface further away from the hub, the ring surface of the near-edge zone 4 is, in this case, perpendicular to the axis of rotation. In this zone, lower edges of numerous abrasive flaps B which are rectangular in this embodiment are fixed with glue bonds 5 with regular spacings of the central angle. The abrasive flaps B overlap one another subsequently in the circumferential direction in the location of the exposedrear edges. The carrying disc A has a structure of a polymer composite with structural reinforcement consisting of at least two meshes made of 7.7p glass fibre. In the embodiment shown in FIG. 3, a mesh of glass fibre with 7p paper glued to it is moulded into the upper frontal surface of the carrying disc A and bonded through the inner layer of the composite matrix 6 with a bare mesh of glass fibre (7) moulded into the lower frontal surface under the abrasive flaps (B). The composite matrix 6 contains a binder of thermosetting synthetic resin, a fine-grained material and possibly conditioning additives. The subsequent FIGS. 4 and 5 of the drawing show embodiments with a higher strength, with layers of bare mesh 7 penetrable for the volume of the composite 95 matrix 6, the layers being additionally introduced into the inner structure.

[0014] Exemplary layered structures of carrying discs and compositions of composite matrices are presented below in three exemplary embodiments.

EXAMPLE I

[0015] Layered structure of carrying disc: [0016] steel sleeve, [0017] bare mesh of glass fibre with paper glued to it, with a weight of 235 [g/m.sup.2], [0018] bare mesh of glass fibre with a weight of 245 [g/m.sup.2], [0019] composite mass, [0020] bare mesh of glass fibre with a weight of 245 [g/m.sup.2], [0021] bare mesh of glass fibre with a weight of 198 [g/m.sup.2], [0022] steel sleeve.

[0023] Composite Mass: [0024] fine-grained material: quartz sand with a medium grain size of 1.35 mm and a medium hardness of 6. according to the Mohs scale85.0 wt. %, [0025] SW-Supraplast 04 type liquid phenolic resin3.5 wt. %, [0026] MD 1/11 powder phenolic resin11.5 wt. %.

EXAMPLE II

[0027] Layered Structure of Carrying Disc: [0028] steel sleeve, [0029] bare mesh of glass fibre with paper glued to it, with a weight of 235 [g/m2], [0030] bare mesh of glass fibre with a weight of 245 [g/m2], [0031] composite mass, [0032] bare mesh of glass fibre with a weight of 245 [g/m2], [0033] composite mass, [0034] bare mesh of glass fibre with a weight of 245 [g/m2], [0035] bare mesh of glass fibre with a weight of 198 [g/m2], [0036] steel sleeve.

[0037] Composite Mass: [0038] fine-grained material: quartz sand with a medium grain size of 1.35 mm and a medium hardness of 6. according to the Mohs scale60.0 w %, [0039] copper slag with an average grain size of 1.45 mm14.60 wt. %, [0040] SW-Supraplast 04 type liquid phenolic resin4.75 wt. %, [0041] MD 1/11 powder phenolic resin12.65 wt %, [0042] calcium carbonatecalfix8.00 wt. %.

[0043] The disc features increased rigidity caused by the addition of calfix and introduction of an additional mesh into the matrix layer.

EXAMPLE III

[0044] Layered Structure of Carrying Disc: [0045] steel sleeve, [0046] bare mesh of glass fibre with interlining glued to it, with a weight of 100 [g/m2], [0047] bare mesh of glass fibre with a weight of 140 [g/m2], [0048] bare mesh of glass fibre with a weight of 198 [g/m.sup.2] [0049] composite mass, [0050] bare mesh of glass fibre with a weight of 245 [g/m2], [0051] composite mass, [0052] bare mesh of glass fibre with a weight of 198 [g/m2], [0053] bare mesh of glass fibre with a weight of 198 [g/m2], [0054] steel sleeve.

[0055] Composite Mass: [0056] fine-grained material: quartz sand with a medium grain size of 1.35 mm and a medium hardness of 6 according to the Mohs scale52.70 wt. %, [0057] copper slag with an average grain size of 1.35 mm14.60 wt. %, [0058] blast furnace milled slag with a grain size of 1.35 mm7.30 wt %, [0059] SW-Supraplast 04 type liquid phenolic resin4.25 wt. %, [0060] MD 1/11 powder phenolic resin10.75 wt. %, [0061] red pyrite4.00 wt. %. [0062] barite6.40 wt. %

[0063] A disc with 6 meshes of glass fibre, with diverse weight and weaves, bonded by a matrix with a smaller amount of the binder and filler features the required rigidity, good removal of particles from underneath the abrasive flaps, good discharge of heat and fluent wear of the carrying disc.