METHOD OF FORMING A GRINDING OR POLISHING DISC AND A GRINDING OR POLISHING IMPLEMENT COMPOSED OF SEVERAL SUCH DISCS

Abstract: A grinding- or polishing implement can be produced by providing a rectangular sheet (1) at both sides with segments (2) formed by slits from the outside towards the centre. Hereafter the sheet is folded around the centre across a glue string (5), and then the two folding edges are folded together and glued together for the formation of a closed ring. This ring can thereafter be placed on a spindle (6) preferably between retaining discs (8). In this way raw material can be saved in the production of rings, just as the rings can be used more economically in an implement as the grinding qualities are improved through the big number of segments, their completely uniform size and placing along the periphery of the implement and their ability to adjust and shape themselves according to the prepared members An implement can be produced by disposing such rings between retaining discs (8) on a rotating spindle (6), and in order to secure the rings the spindle (6) can at its end have one or more guide facings (10), in which a co-operating guide pin (12) on a disc (7) can slide and be axially displaced by being tightened together with a bolt (11).

Description: METHOD OF FORMING A GRINDING OR POLISHING DISC AND A GRINDING OR POLISHING IMPLEMENT COMPOSED OF SEVERAL SUCH DISCS The invention relates to a method for producing a grinding- og polishing disc in which the grinding members are flexible 3 and to a grinding- or polish¬ ing machine for this purpose. Grinding- or polishing discs are used as rotating implements of different kinds. Usually the abrasive active medium is provided with abrasive grits,, but non-abrasive mediums are also used for removing e.g. surface coatings such as rust or the like. Hitherto known discs of this kind are produced by way of some kind of fastening of the abrasive medium to a carrier in the shape of a solid of revolution. It can be glued on or by mechanical means be fastened to the carrier. Such discs are difficult to produce as they must have a uniform grinding surface and, if it should be pos¬ sible to replace destroyed or worn members, also be provided with means which admit a replacement of the components. Moreover the materials consumption is very large as the single components must be produced separately and thereafter be_assembled. It is the object of this invention to meet these de¬ fects and indicate an improved method for the prod- uction of such discs, and this is achieved by cutting through a rectangular sheet at its full length from a distance from the centre and out to the opposite lateral edges for the formation of a number of seg¬ ments, whereafter the sheet is folded up around the centre and then bent and joined together with the central portion against the central portion of the opposite end for the formation of a closed ring. By using this method it is achieved in a hitherto un¬ known and. simple way to produce a ring with grind¬ ing- or polishing segments regularly disposed along ;. * the whole periphery of the ring, which segments all represent a portion of the closed ring formed from one single sheet. The formation of the grinding seg¬ ments is done by a slit of the two sides of the sheet from the basic material, and the ring is formed by folding this sheet in the first place around the cent- re and then folding it for the formation of the closed ring. This ring" member can now be assembled either alone or together with adjacent rings for the form¬ ation of an implement. 3y using this method is thus a saving of materials of at least 35 per cent achieved in relation to a punching of a corresponding ring in one single sheet,at the same time as the number of segments is doubled, as the ring according to the in¬ vention gets two segments on top of each other. Thus the number of rings on an implement can be considera- bly reduced as the grinding capability is thereby con¬ siderably increased. At the same time a completely .. exact arrangement of the single grinding segments with the same length and characteristics is achieved in a simple way. This results in the wanted regular grinding capability which can usually only be achiev¬ ed by an extensive after-treatment of the implement. Moreover the method secures that the grinding segments can rotate around their longitudional axis, as the method secures that the single segments are placed at a suitable distance to the adjacent segments. This means that the implement becomes self-regula ing, as the segments will adjust themselves to " the prepared member. If the member is even the segments rotate a- bout 90 and grind completely evenly, while rhey in case of a profiled member will adjust themselves to ' this by rotating more or less. The grinding effect is thus adjusted to the shape and nature of the sur¬ face. By inserting a stringin the folding line in the centre as described in claim 2, is in a simple way partly a joint of the folded edge and partly a joint of the ring itself secured. This string can e.g. consist of a hot' melt adhesive material, or, in case of a metal sheet, a fitted soldering material could be used. By using a machine as described in claim 3 3 a grind¬ ing implement can be produced, which grinds complete- y evenly, and which besides is simple to take apart and assemble. By using a spindle and a tension disc as described in claim. 4, the. implement can quickly be tightened toge- ther and the rings be retained in a safe way. The invention will now be elucidated further in detail with reference to the annexed drawing in which Fig. 1 shows a sheet after the segments have .. • been punched, Fig. 2 shows the sheet after the ring has been formed, Fig. 3 shows an implement comprising a spindle with rings and discs, Fig. 4 shows the lower part of the spindle, and Fig. 5 shows the spindle along the line Y-V in fig.- 4. As shown in fig, 1 the basic material is a rectangular sheet 1, which can be of an abrasive kind, e.g. emery cloth, og of a non-abrasive kind, e.g. plastic, skin or metal. The sheet is at its full length at both sides of the centre line provided with parallel slits 3, by means of which segments 2 appear at both sides of the centre The segments have the same length and the same width. Then a string 5 is inserted in the centre along the length of the sheet. The stringcan, where the sheet can be glued together, be of e.g. a hot melt mat¬ erial. In case of metal, the stringcan perhaps be of a soldering material. The sheet is now folded together around the centre so that the segments 2 lie on top af each other. There¬ after folding edge is put against folding edge so that the strin 5 is assembled for the formation of a closed ring as shown in fig. 2. The stringis melted by means of heat, and the ring is ready. Instead of a stringa closed ring, around which „ the sheet is folded, could be used. In fig. 3 the rings are shown placed on a spindle β for the formation of the implement. On the spindle there is a stop on which a disc is mounted. Under this a retaining disc 8 of e.g. piastic is placed. The disc 8 is at its top side provided with a cavity and at its under side with a turning down at the extremi- ty. The shape is clearly seen in cross section in fig. " 3, Besides there are sloping edges 9 from cavity to surface and opposite from- surface to ring--. In. fig. 4 and 5 the lower portion of .the spindle β • is shown. At the centre it is provided wit a tapped hole in which a bolt 11 can be screwed. At the peri¬ phery of the spindle three ' guide facings 10 are placed in which corresponding pins 12 disposed on a disc 7 can be axially displaced. When the bolt is tightened together an axial displacement of the disc takes place and with it a pinching together of discs and rings disposed in layers on the spindle. The guide pins secure that the disc- 7 cannot be rotated in relation to the spindle, by means of which the bolt 11 is locked to the spindle. This secures that the bolt does not unscrew itself during operation of the implement and so does, not slacken the single rings and discs. When constructing the implement a retaining disc and a ring are in turn placed on the spindle. The interior of .the ring with binding material and folding edges is held in between the two retaining discs 8 at both sides of the ring. At the bottom a disc 7 and some kind of a locking device is shown. This can be a bolt or a similar tightening device, by means of which rings and discs can be tightened together so that they are firmly locked to the spindle. In this way an implement can be constructed which has flexible segments disposed regularly all over the periphery so a fast, even and exact grinding process can be obtained.

Claims: C L I M S 1. A method for producing a grinding- or polishing disc..in which the grinding members are flexible, c h a r a c t e r i z e d in that a rectangular sheet (1) at its full length from a distance from the centre and out to the opposite lateral edges is cut through for the formation of a number of segments (2), where¬ after the sheet (1) is folde up around the centre and then bent and. joined together with the central portion against the central portion of the opposite end for the formation of a. closed ring. 2. A method according to claim 1, c h a r a c t e.- r i z e d in that a string (5) af a . hot melt mat¬ erial is inserted in the folding line and after the folding is heated, thus forming the ring. 3 - A., grinding- or polishing machine which works with rings produced according to the method described in claims 1 and 2, and where the rings are disposed on a rotating spindle, c h a r a c t e r i z e d iin that a retaining disc (8) is placed between each ring and pinches around the inner edge (4) of the ring. 4, A grinding- or polishing machine according to claim 3, c h a r a c t e r i z e d in that the spindle (6) at its end is provided with one or more peripheral guide facings (10) plus a central tapped hole, and with a disc (7) with a guide pin (12) which can slide in the guide facings (10) ' and with a central hole for a bolt (II) to be screwed into the tapped hole thus pinching the rings tightly between the retaining discs (8).

Inventors: HUNDEBOL KELD O
Applicants: HUNDEBOL KELD O
Application year: 1981
Main classification: B24D13
IPC codes: B24D13