Classifications

• • A—HUMAN NECESSITIES
  • A46—BRUSHWARE
  • A46D—MANUFACTURE OF BRUSHES
  • A46D3/00—Preparing, i.e. Manufacturing brush bodies
  • A46D3/02—Machines for drilling bodies
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B24—GRINDING; POLISHING
  • B24D—TOOLS FOR GRINDING, BUFFING OR SHARPENING
  • B24D13/00—Wheels having flexibly-acting working parts, e.g. buffing wheels; Mountings therefor
  • B24D13/02—Wheels having flexibly-acting working parts, e.g. buffing wheels; Mountings therefor acting by their periphery
  • B24D13/10—Wheels having flexibly-acting working parts, e.g. buffing wheels; Mountings therefor acting by their periphery comprising assemblies of brushes
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B24—GRINDING; POLISHING
  • B24D—TOOLS FOR GRINDING, BUFFING OR SHARPENING
  • B24D9/00—Wheels or drums supporting in exchangeable arrangement a layer of flexible abrasive material, e.g. sandpaper
  • B24D9/003—Wheels having flaps of flexible abrasive material supported by a flexible material

Definitions

• the present invention relates to a method for manufacturing a sweeper or abrasive element for use in a rotating sweeper, abrasive or polishing tool and comprising brist ⁇ les or lamellae of abrasive cloth and rigidifying bristles, which are retained in a sub ⁇ stantially U-shaped profile.
• the invention has originated in the context of manufacturing rotating abrasive and polishing tools.
• the invention may also advantageously be used in the con ⁇ text of sweeper tools such as known, e.g. from brushes mounted on tractors or from other rotating brushes where the sweeper brushes are generally embedded for squeez ⁇ ing in a metal U profile.
• sweeper tools such as known, e.g. from brushes mounted on tractors or from other rotating brushes where the sweeper brushes are generally embedded for squeez ⁇ ing in a metal U profile.
• the invention primarily originates from the context of abrasive or polishing tools, the following explanation will mainly be based on the dis ⁇ advantages associated with such tools and, likewise, the advantages of the invention will also primarily be explained in the context of such tools.
• Rotating abrasive or polishing tools provided with abrasive elements are known. Such tools are used extensively in the woodworking industry.
• Abrasive elements of the type comprising abrasive cloth and rigidifying bristles have obtained widespread use as they give a good result when grinding profiled wooden items.
• Abrasive or polishing tools of the type in which the abrasive element is used have so far primarily been used for grinding and polishing non-plane surfaces such as curved furniture parts, panelled doors, etc.
• the lamellae of the abrasive element are formed by cutting an abrasive cloth transversely of its longitudinal direction so that strips or lamellae appear, which are at one end interconnected by means of an unbroken tape secured to the U profile.
• the abrasive or polishing effect is obtained as a result of the effect of the lamellae as they sweep over the item during rotation of the tool.
• the ri ⁇ gidifying brushes as indicated by the word, have a function of supporting the abrasive lamellae. However, the brushes may also be produced from such a material that they contribute to the abrasive or polishing effect.
• a known tool of this type is designated "Flatter polisher”.
• Abrasive or polishing tools of this type are disclosed, e.g. in Danish patent applications No. 191/91 and No. 849/92. These applications also disclose abrasive elements of the type mentioned in the introduction.
• Such tools are formed by a number of circular or helical abrasive elements arranged in parallel.
• the abrasive elements are arranged in a track in a cylinder shell so that a cy ⁇ lindrical abrasive or polishing tool is formed, which has an abrasive or polishing effect from its cylindrical circumference.
• the abrasive or polishing effect of the tools appears as a result of the effect of the la ⁇ mellae during the flexible sweeping of the item during rotation of the tool.
• the centrifugal force will contribute to the abrasive or pol ⁇ ishing pressure necessary for the treatment.
• the rigidity of the lamellae themselves will be important in order to produce the necessary abrasive or polishing pressure.
• the supporting brushes inserted next to the lamellae will also serve to increase the abrasive pressure of the lamellae, and the brushes may be pro ⁇ quizd from a material contributing to the abrasive or polishing process.
• Polishing i.e. grinding and inter-paint polishing of wood, is performed in order to obtain the best possible surface quality.
• Polishing items that are profiled, or which have a complex shape make heavy requirements on the polishing technique used.
• the polishing tools and their polishing or abrasive elements must necessarily be very flexible and must be able to adapt to items to be polished in order to ensure a uniform treatment of the surface. Thus, there must be no grinding of edges, and it also has to be ensured that polishing or grinding is established in grooves and adjacent projections.
• the lamellae and the brushes are placed in a U- shaped metal profile, which is subsequently squeezed together around the abrasive lamellae and the brushes.
• Squeezing of the U profile is performed in such a manner that brushes and lamellae are retained mechanically in the profile. Retention might be improved by means of a metal wire or plastic wire inserted in the U bottom. Said wire increases the cross-section area under the squeezed sides of the U profile. This im ⁇ proves retention as the brushes and possibly also part of the lamellae are folded around the wire. In squeezing the U profile, it is simultaneously given a cross-section shape fitting into undercut tracks in the abrasive or polishing tool.
• the known abrasive elements have furthermore turned out to be disadvantageous in that they lose some of the bristles and/or lamellae after use for some time.
• a plastic profile having a bottom and two legs projecting upward from it, which is manufactured in a compressed state so that the legs are elastically yielding pressed" towards each other, so that the profile has a substantially triangular longitudi- nal cross-section in an initial state, and which is flexible in the longitudinal direction according to a plan perpendicular to the U bottom, that said profile is advanced, that the two U legs are spread, and that between them bristles are inserted between the two legs, or abrasive lamellae are inserted adjacent a first one of the two U legs and rigidi ⁇ fying bristles adjacent the second leg, that in the bottom of the U an adhesive member for gluing the bristles or the bristles and abrasive lamellae is inserted, that the U pro ⁇ file is brought back to its point of origin, the upper ends of the two legs approaching each other and thus squeezing the bristles or the lamellae
• the profile may be manufactured in endless lengths by continuous convey ⁇ ance of the U-shaped profile into which bristls and lamellae are inserted. After adher ⁇ ence and a deformation of the U profile have taken place, the latter may be cut into desired lengths without any risk that the outermost lamellae and bristles in the cut lengths of the abrasive element would fall out or become loose during use. Conse ⁇ quently, the U-shaped profile may be cut into any arbitrary length required for a given abrasive or polishing tool.
• the U-shaped profile may easily be adapted to the tool and will also be able to be adapted to any diameter of the tool since the U-shaped profile is made flexible in the plane perpendicular to the bottom of the U.
• a flexible U-shaped plastic profile is used in which the distance between the upper ends of the U legs in a non-deformed state is shorter than the distance between the lower ends of the U legs.
• a plastic profile is used in which the legs themselves have an elastic force towards each other in order to squeeze around the brushes and lamellae placed between the U legs.
• the adhesive member pre ⁇ ferred for the adhesive member to be a fusible plastic thread.
• Heating may take place thermally or by ultrasound.
• This may be accomplished in a suitable manner by conducting the U profile with the brushes and lamellae arranged therein through a matrix. During a subsequent cooling the plastic profile may, by means of a suitably shaped matrix, be given a de ⁇ sired outer contour. This will frequently be a cross-section shape making it possible to place the abrasive element in a dovetailed or T-shaped track in the cylindrical surface of the abrasive tool.
• abrasive element ready for use, it is preferred, before cutting the abrasive element into desired lengths, to perform a separation of bristles and lamellae and a cut of the bristles into a length that is adapted to the length of the lamellae used. In this manner an optimal relation between the bristles and lamellae is obtained so that a tool may be put to use as soon as the abrasive element has been inserted.
• the bristles are laid down by bristle threads being conveyed to the spread-out U pro ⁇ file with an orientation transversely of the U profile in such a manner that the centres of the bristles are situated approximately at the U profile. Then the centres of the bris- ties are pressed down into the U profile. This may take place simultaneously with laying down the adhesive member/the tread. Under this pressure the two bristle ends will project upward and will then have unequal lengths. Alternatively, the bristles may also be introduced with one end inserted into the U profile. Also in this case there will be an uncertainty as to the bristle length since the bristles may be displaced at a shorter or longer distance into the U profile.
• the U profile is given a cross-section contour that has larger width at the bottom of the U profile.
• the undercut track and the cross-section contour of the profile will then contribute to the appearance of a wedging effect so that the U legs are squeezed together and thus contribute to a secure retention of the sweeper bristles or the rigidifying bristles and lamellae in the element even if certain lamellae and/or bristles are not fully embedded or retained by the applied adhesive.
• Such additional adhesive member may either be placed on the lamellae before inser ⁇ tion into the U profile or during insertion into the U profile simultaneously with insert ⁇ ing the adhesive member first mentioned.
• a sweeper or abrasive element according to the invention is characterised in that the profile is at least partially manufactured from plastic and is composed of a bottom and two legs projecting upward from it, said profile being flexible in the longitudinal di ⁇ rection according to a plan perpendicular to the U bottom, and wherein the legs are manufactured in a compressed state so that they are elastically yielding pressed to- wards each other, so that the profile has a substantially triangular longitudinal cross- section in an initial state, the distance between the upper ends of the U legs in a non- deformed state being shorter than the distance between the lower ends, and that the sweeper bristles or the abrasive lamellae and rigidifying bristles are retained in the U by an adhesive member in tht form of plastic originating from a plastic thread be- tween the sweeper and rigidifying bristles and from the inside of the profile, which have been heated above the plasticisation temperature so that the plastic encloses the sweeper bristles or the rigidifying bristles and abras
• Such a sweeper or abrasive element is advantageous because an integral unit is formed so that bristles and lamellae cannot become loose when the sweeper, abrasive or pol ⁇ ishing tool is being used.
• the element is further advantageous because the plastic profile can be bent easily and consequently may be adapted to any diameter of the cylindrical surface of the sweeper, abrasive or polishing tool.
• the element may optionally be delivered to a user in endless lengths or cut into lengths fitting the tools of the individual user. Replacing the sweeper or abrasive element is performed easily and simply by inserting the formed U profile in an undercut track in the tool body. As the distance between the upper ends of the U legs is shorter than the distance between the lower ends, the abrasive element will, as explained above, be retained in the track.
• the abrasive lamellae used will preferably be formed from an elongated abrasive cloth which is slit at one lateral edge. At the other lateral edge the lamellae are thus coherent at the part of the abrasive cloth that has not been slit. With this kind of abrasive cloth a mutual positioning of the abrasive lamellae in the abrasive element is obtained and at the same time handling the manufacture of the abrasive element is easier.
• the abrasive lamellae may be stored in a roll-shape and be unwound from such a roll and conveyed at a velocity corresponding to the conveyance velocity of the U-shaped profile and the adhesive member.
• Fig. 1 illustrates a method according to the invention
• Fig. 2 shows a sectional view through an abrasive element according to the inven- tion during manufacture
• Fig. 3 shows a sectional view corresponding to Fig. 2 through the abrasive element after its manufacture has been completed
• Fig. 4 shows a sectional view through a metal lining
• Fig. 5 shows a lateral view of the metal lining, which may be embedded in the U profile.
• Fig. 1 illustrates an apparatus 1 for the manufacture of abrasive elements 2 by a method according to the invention.
• a flexible U-shaped profile 3 is conveyed from a feeding roller (not shown).
• the two legs of the U-shaped profile are spread apart in a station 4.
• an adhesive member 5 in the form of a plastic thread or alter ⁇ natively of a double-sided adhesive tape is introduced into this station.
• the adhesive member 5 is introduced in vicinity of one leg of the U profile and immediately next to it abrasive lamellae 6 are introduced, which will thus lie adjacent the first of the two legs of the U profile 3.
• the abrasive lamellae 6 are formed by slitting a web- shaped abrasive cloth and are part of the web width. In this manner a coherent edge area 6' appears, which is introduced into the U profile 3 and which ensures a mutual retention of the abrasive lamellae 6. It is preferred for the cut of the abrasive cloth web to be performed in such a manner that during the slitting the abrasive lamellae are given a slight turn so that the abrasive side is oriented at an angle between 2° and 5° in relation to the longitudinal direction of the abrasive element.
• rigidifying bristles 7 are arranged between the two legs of the U.
• the bristles 7 are conveyed from a supply source 8 where they are given a uniform orientation in a vibration device or similar device.
• the bristles are then transferred to an endless conveyor belt 9, which conveys the bristles 7 with an extension transverse of the U profile.
• the conveyor belt 9 has a direction of convey ⁇ ance according to the arrow 10.
• Projecting walls 11 are positioned transversely of the conveyor belt 9. Between the subsequent walls 1 1 a number of bristles will be situ ⁇ ated, which are laid down between the U profile legs at the point 12, a directing mem ⁇ ber 13 pressing the central part of the bristles into the bottom of the U profile.
• a thread-shaped adhesive member in the form of a dissoluble plastic thread 14 is introduced between the U legs.
• the plastic thread 14 is conveyed from a supply roll (not shown) around a roller 15 and laid down by means of a positioning member 16 corresponding to the positioning member 13. In this manner it is ensured that the plastic thread 14 is brought into folded bristles 7 and into the bottom of the U profile.
• the folded rigidifying bristles 7 will be positioned at the second U leg in a position alongside the abrasive lamellae 6.
• the process of introducing the bristles 7 and the plastic thread 14 may alternatively be introduced simultaneously by positioning the plastic thread in imme ⁇ diate vicinity of the conveyor belt so that it extends in a track between subsequent walls 11 and, thus, will keep the bristles 7 in contact with the conveyor belt and in such a manner that the plastic thread 14 will be laid down into the bottom of the U by the positioning member 14, which folds and conducts the rigidifying bristles 7 into the U bottom.
• the U profile with the bristles, abrasive elements and plastic thread arranged therein is now conducted to a unit 17 where the upper ends of the two legs are brought towards each other in order to squeeze the lamellae and bristles.
• the unit 17 is provided with heating members so that a heating above the plasticisation temperature of the plastic thread 14 is per ⁇ formed simultaneously. The temperature will simultaneously lead to at least a partial plasticisation of the U profile so that plastic from the plastic thread and the inner side of the U profile is made to enclose the bristles 7 and the abrasive lamellae 6 for for- mation of an integral unit.
• Plastic from the plastic thread 14 and the U profile 3 will thus coalesce and form a completely integral unit, wherein the bristles 7 and the lamel ⁇ lae 6 are embedded and form a part. It will then not be possible to separate the differ ⁇ ent components from each other without ruining the abrasive element formed.
• the U profile is then cooled under the plasticisation temperature. This may preferably take place in the last half of the unit 17. Alternatively a separate cooling unit may be ap ⁇ plied.
• the elongated abrasive element thus formed is then conducted to a unit 19 in which the aligned bristles 7 and abrasive lamellae 6 are separated.
• the abrasive lamellae are brought aside so that the bristles 7 may be cut to a uniform length.
• point 18 how the abrasive lamellae are laid down and the bristles 7 appear with non-uniform length.
• the bristles After passage through a cutting member 19' in the unit 19 the bristles appear with uniform length at a position 20.
• This cutting of the bristles 7 is advantageous for manufacturing an abrasive element 1 that is ready for use directly after it has left the manufacturing apparatus.
• the separation or spreading of the abrasive lamellae or the bristles will cease.
• the abrasive element may then be cut into desired lengths in a cutting unit 21. Then abrasive elements 2 in the desired length appear.
• a U profile of rubber or other flexible material may also be used. It should only be ensured that the profile has such flexibility or compliance that it is able to adapt to different diameters when the profile is inserted into tracks on an abrasive or polishing tool.
• the unit 17 will be designed in such a manner that during heating and subsequent cooling a static deformation of the U profile is per ⁇ formed so that the cross-section contour will have a larger dimension at the U bottom than at the abrasive lamellae and the bristles. Due to this the U profile may be inserted into undercut tracks, which may for example be dovetailed or T-shaped.
• the abrasive element thus produced may easily and quickly be inserted into existing abra- sive or polishing tools, the cylinder surfaces of which are provided with tracks that have previously been designed to receive abrasive elements having a metal U profile.
• the user does not need to store a large number of abrasive elements that are adapted to different diameters of the tools.
• an abrasive element is seen such as it will appear immediately after laying down the plastic thread 14 but before heating and deformation.
• the U will have its legs spread apart.
• the legs of the U are spread to a state in which they extend in parallel with each other.
• the U legs may be spread even wider in order to create as much space as possible between the legs.
• the abrasive lamellae 6 are introduced at the first leg 22 whereas the bristles 7 are introduced in vicinity of the second leg 23 of the U profile.
• the bristles 7 and the thread 14 inside the U profile form an integral unit, which may be conceived of as a plastic matrix in which part of the threads 7 and part of the abra ⁇ sive lamellae 6 are embedded. It has been said above that part of the plastic of the U profile is plasticised. It is noted, however, that this is not necessary. Thus, it may be sufficient that the threads 5 and 14 are plasticised and fill out the cross section area inside the deformed U profile together with the bristles 7 and the abrasive lamellae 6.
• a metal lining 26 is shown.
• the metal lining is optional and is used in order to contribute to establishing a squeeze around the sweeper bristles or the ri- gidifying bristles and abrasive lamellae in addition to the retention effect obtained due to the compression of the two legs 22, 23 of the U.
• the metal lining 26 is produced with a plate-shaped part 27 designed to be placed em ⁇ bedded in the bottom 28 of the U-shaped profile. At either side of the plate-shaped part 27 tooth-shaped or comb-shaped projections 29 are formed, which are designed to extend partially into the legs 22, 23 of the U-shaped profile.
• the tooth-shaped projections 29 may be given an inwardly ori ⁇ ented fold so that they contribute to retaining the profile legs 22, 23 in their oblique inwardly oriented position where they squeeze the embedded bristles/abrasive lamel- lae. In this manner the risk of an unintended separation of the plastic profile and the bristles/abrasive lamellae positioned therein is reduced during transport, storage and handling of a sweeper or abrasive element before it is mounted in a tool.
• FIGS 4 and 5 a cross-section, respectively a side view of a lining 26 is seen. It is noted, however, that the tooth-shaped projections may have other shapes than the sev ⁇ ered triangles shown. It is only important that the projections 29 have such a shape that the formed sweeper or abrasive element 2 may easily be bent in the plane per ⁇ pendicular to the bottom 28 of the U-shaped profile so that the element may easily be adapted to the curve of the tool in which it is to be mounted.
• the lining will preferably be produced from aluminium but other very flexible metals may also be used.

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Citations (4)

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• 1996
  • 1996-03-26 DK DK199600345A patent/DK172548B1/da not_active IP Right Cessation
• 1997
  • 1997-03-26 US US09/155,207 patent/US6217124B1/en not_active Expired - Fee Related
  • 1997-03-26 AT AT97914178T patent/ATE219411T1/de not_active IP Right Cessation
  • 1997-03-26 ES ES97914178T patent/ES2180957T3/es not_active Expired - Lifetime
  • 1997-03-26 DK DK97914178T patent/DK1011925T3/da active
  • 1997-03-26 WO PCT/DK1997/000140 patent/WO1997035688A1/en active IP Right Grant
  • 1997-03-26 EP EP97914178A patent/EP1011925B1/en not_active Expired - Lifetime
  • 1997-03-26 DE DE69713527T patent/DE69713527T2/de not_active Expired - Fee Related
• 1998
  • 1998-09-24 NO NO19984439A patent/NO310708B1/no not_active IP Right Cessation

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