Machine and method for making brushes, and brush made thereby

Abstract

A machine (1) for making twisted wire brushes (100) comprises first feeding means (2) for moving and / or arranging two wire portions (53a, 53b; 51a, 52a) made of plastic material adjacent to and parallel to a working axis (W); second feeding means (3) for supplying and inserting between the two wire portions (53a, 53b; 51a, 52a) a respective fiber bundle (60) made of plastic material; gripping means (4) for grasping the ends (53c; 51b, 52b) of the wire portions (53a, 53b; 51a, 52a) and movable along and about the working axis (W) to twist the wire portions (53a, 53b; 51a, 52a) on each other so as to block the respective fiber bundle (60) between them and form a brush (100); heating means (5) arranged between the first feeding means (2) and the gripping means (4) to heat the wire portions (53a, 53b; 51a, 52a) at a defined operating temperature (Tw) for a defined heating time (tr) so as to make the wire portions (53a, 53b; 51a, 52a) stiff and stable, in the twisted configuration (A), after their cooling; and fixing means (25; 35) interposed between the first feeding means (2) and the gripping means (4) and configured to fix a respective fiber bundle (60) to at least one of the wire portions (53a, 53b; 51a, 52a).

Description

[0001] Machine and method for making brushes, and brush made thereby

[0002] The present invention relates to machines for making brushes of elongated shape made of twisted wire, obtained by twisting or torsion of two wire portions that block a bundle of bristles or fibers.

[0003] Machines are known for making brushes, such as pipe cleaners or interdental brushes, made of twisted wire, in which two metal wires unwound from respective reels, are arranged parallel and longitudinally and a flattened bundle of bristles or fibers is inserted between said wires. The latter are then twisted or wrapped around each other along a longitudinal axis so as to block the bristles and arrange them radially in a substantially cylindrical shape. Also known are machines for making twisted wire brushes in which a single metal wire is used that is unwound from a reel and cut to size to obtain a section or portion of defined length, which is bent on itself in a "U" shape so as to receive the flattened bundle of bristles or fibers. The bent section is then twisted on itself along a longitudinal axis to form the elongated body of the brush in a portion of which the fibers, which in the twisting process are arranged radially in a substantially cylindrical shape, are blocked.

[0004] In both types of brushes, metal wire is used, possibly coated with a plastic film, since the metal material, once plastically deformed during the twisting process, forms a body that stably maintains the assumed shape and ensures firm and durable retention of the fibers. The latter can be made of synthetic, natural or metallic material.

[0005] In the event that the fibers are made of synthetic material, for example plastic material, the problem arises of the recyclability of the brush which is composed of plastic material elements (the fibers) and metallic elements (the twisted wire sections that form the body of the brush), said elements not being able to be disposed of together. In order to properly dispose of and therefore recycle the brush, the plastic fibers must be extracted and disposed of separately, making the entire recycling process complex and expensive.

[0006] US 2019 / 125069 describes a device for the production of round brushes including bristles clamped between two portions of twisted wire. The device comprises drive rollers actuated by a motor and configured to move the wire along a longitudinal direction, a bending element movable transversely with respect to the wire, and opposed counter-brackets spaced apart from each other and arranged on a side of the wire opposite the bending element. The latter can be moved between the counter-brackets to bend the V- or U-shaped wire and form two wire portions. The device also includes a bristle feeding device adapted to insert the bristles between the two bent wire portions and a rotating gripper configured to grasp the bent wire and then twist it during the feeding of the bristles so as to anchor them to the wire.US 2008 / 034524 describes a small diameter twisted wire brush formed by a plurality of radially protruding resin bristles or filaments mounted on and blocked by two or more stems that are also twisted and made of resin.

[0007] An object of the present invention is to improve known machines and methods for making twisted wire brushes.

[0008] Another object is to provide a machine and a method that allow to make twisted wire brushes using only plastic materials and therefore completely recyclable.

[0009] A further object is to provide a machine and a method that allow to make brushes in twisted wire in which the fibers and bristles in plastic material are fixed to the body of the tool in a firm and stable way.

[0010] Still another object is to make a simple and inexpensive twisted wire brush made entirely of plastic material, therefore completely recyclable.

[0011] A first aspect of the invention provides a machine for making brushes according to claim 1. A second aspect of the invention provides a method for making brushes according to claim 14.

[0012] A third aspect of the invention provides a twisted wire brush according to claim 19.

[0013] The invention can be better understood and implemented with reference to the attached drawings which illustrate an exemplifying and non -limiting embodiment thereof, in which:

[0014] Figure 1 is a partial front view of the machine for making brushes of the invention in which gripping means are arranged in a first operating position to grasp a wire section to be twisted;

[0015] Figure 2 is an enlarged front view of the machine shown in Figure 1, in which some parts have been removed to better highlight others;

[0016] Figure 3 is a partial front view of the machine shown in Figure 1, in which the gripping means are in a second operating position;

[0017] Figure 4 is an enlarged partial perspective view of the machine shown in Figure 1 ; Figure 5 is an enlarged partial section along the V-V plane of Figure 1;

[0018] Figure 6 is an enlarged partial section along the VI- VI plane of Figure 1 ;

[0019] Figure 7 is a schematic front view of a brush made by the machine shown in Figure 1; Figures 8 and 9 are enlarged and partial front views of a variant of the machine of the invention respectively in a bending phase of a wire section and in a twisting phase of the wire section;

[0020] Figures 10 and 11 are enlarged and partial front views of another variant of the machine of the invention respectively in a bending phase of a wire section and in a twisting phaseof the wire section;

[0021] Figure 12 is a partial front view of a bent wire section;

[0022] Figure 13 is an enlarged front view of heating elements of the machine of Figure 8 associated with a bent wire section.

[0023] With reference to Figures 1 to 6, the machine 1 of the invention is shown, which is arranged to make brushes, bottle brushes, pipe cleaners, interdental brushes and the like in twisted wire, in particular brushes 100 comprising a body 101 formed by two portions 53a, 53b; 51a, 52a of at least one wire 50; 51, 52 of plastic material, in particular of a thermoplastic polymer, twisted on each other along a longitudinal axis X so as to block a fiber bundle 60 inserted between them, the fibers or bristles 61 of the bundle 60 being also made of plastic material. In particular, the wire 50; 51, 52 and the fibers 61 of the bundle 60 are made of the same plastic material, for example ABS, PP, so as to have a mono-material brush.

[0024] The machine 1 of the invention comprises first feeding means 2 arranged to move and / or arrange two wire portions 51a, 52a at a time, adjacent to and parallel to a working axis W, second feeding means 3 for supplying and inserting a respective fiber bundle 60 between the two wire portions 51a, 52a and gripping means 4 configured to grasp the ends 51b, 52b of the wire portions 51a, 52a and movable along and about the working axis W to twist the two wire portions 51a, 52a on each other in a twisted configuration A so as to block the respective fiber bundle 60 between and make the brush 100.

[0025] In the embodiment of the machine 1 of the invention shown in Figures 1-6, the two wire portions 51a, 52a are obtained from respective wires 51, 52 unwound from corresponding reels 55, 56.

[0026] The machine 1 also comprises heating means 5 interposed between the first feeding means 2 and the gripping means 4 and arranged to heat the wire portions 51a, 52a supplied by the first feeding means 2 at a defined operating temperature Tw for a defined heating time tr, in particular before the aforementioned wire portions 51a, 52a are twisted, so as to make the wire portions 51a, 52a stiff and stable in the twisted configuration A.

[0027] The machine 1 also comprises fixing means 25 interposed between the first feeding means 2 and the gripping means 4 and configured to fix a respective fiber bundle 60 to at least one of the wire portions 53a, 53b.

[0028] The defined operating temperature Tw is between a lower operating temperature Twi and an upper operating temperature Tws, wherein the lower operating temperature Twi and the upper operating temperature Tws define an operating temperature range ATw that includes a glass transition temperature Tg of the plastic material of the wire portions 53a, 53b; 51a,52a. The lower operating temperature Twi is e.g. about 20°C lower than the glass transition temperature Tg and the upper operating temperature Tws is about 45°C higher than the glass transition temperature Tg.

[0029] As is known, in a thermoplastic polymer at the glass transition temperature Tg the movements of the polymer chains that compose it are reduced and the material becomes compact and stiff, thus maintaining the shape assumed before heating. In the case in question, the wire portions 51a, 52a, twisted after their heating to an operating temperature Tw close to or in any case not far from, in particular less than about 15 °C, from the specific and respective glass transition temperature Tg for the defined heating time tr, maintain, once cooled to room temperature, the deformation undergone, that is, they remain substantially stiff and stable in the twisted configuration A.

[0030] In the embodiment of the machine 1 of the invention illustrated in Figures 1 to 6, the first feeding means 2 comprise first unwinding means 21 adapted to unwind a first wire 51 made of plastic material from a first reel 55 and move a respective portion 51a thereof at a time towards the heating means 5 and second unwinding means 22 to unwind a second wire 52 made of plastic material from a second reel 56 and move a respective portion 52a thereof at a time towards the heating means 5.

[0031] The first unwinding means 21 and the second unwinding means 22 are of a known type and comprise rollers and guides capable of guiding and deflecting the wires 52, 52 towards the heating means 5 and the gripping means 4.

[0032] The gripping means 4 comprise a gripper 40 of known type, supported by an operating head 41 and rotatable about the working axis W. In particular, the gripper 40 is rotated about the working axis W by a first motor 42, for example a rotary electric motor. The operating head 41 and with it the gripper 40 are also linearly movable along the working axis W. In particular, the operating head 41 is slidably mounted along linear guides 43 on a support frame 20 of the machine 1 driven by a second motor 45.

[0033] The heating means 5 comprise a first heating element 6 and a second heating element 7 arranged parallel and facing each other. Each heating element 6, 7 comprises a respective operating wall provided with a guiding groove 8, 9 suitable for receiving and guiding along the working axis X a respective wire portion 51a, 52a to be heated. More precisely, the first heating element 6 and the second heating element 7 have an elongated shape and comprise respective guiding grooves 8, 9 rectilinear and parallel to the working axis W. In particular, the first heating element 6 comprises a first guiding groove 8 that faces and opposes a second guiding groove 9 of the second heating element 9.In the embodiment of the machine 1 of the invention illustrated in Figures 1 to 3, the fixing means comprise dispensing means 25 interposed between the first feeding means 2 and the heating means 5 and arranged to dispense on at least one of the two wire portions 51a, 52a entering the heating means 5, preferably on both wire portions 51a, 52a, a joining substance or material, for example a glue or adhesive, adapted to join together the two wire portions 51a, 52a and the fibers 61 of the fiber bundle 60. For example, the dispensing means 25 comprise a pair of dispensing nozzles each adapted to dispense the joining substance on a respective wire portion 51a, 52a. The dispensing nozzles of the dispensing means 25 are positioned adjacent to the heating elements 6, 7 on the opposite side with respect to the gripping means 4.

[0034] For example, the joining substance is a plastic polymer and can also be the same plastic material as the wire 50 that is dispensed in the molten state by the dispensing nozzles 25. The joining substance fixes the fibers 61 to at least one, preferably both, of the wire portions 51a, 52a and can also fix the latter together, thus making the body 101 of the brush 100, consisting of the two wire portions 51a, 52a twisted about each other along the longitudinal axis X, more stiff and robust.

[0035] Alternatively, as illustrated in Figure 4, the fixing means may comprise welding means 35, in particular of the ultrasonic type, interposed between the first feeding means 2 and the heating means 5 and arranged to weld the fibers 61 of the fiber bundle 60 to at least one of the wire portions 53a, 53b before entering the heating elements 6, 7. Preferably, the welding means 35 may be configured to weld the two wire portions 53a, 53b and the fibers 61 of the fiber bundle 60 together.

[0036] The machine 1 can also comprise cooling means 12 that are positioned downstream of the heating means 5, in particular on the opposite side with respect to the first feeding means 2, and configured to cool the wire portions 51a, 52a after they have been twisted by the gripping means 4 and while they are moving out of the heating means 5 along the working axis W. The cooling means 12 comprise, for example, one or more nozzles 13 arranged to blow a cooling fluid, for example air, onto the wire portions 51a, 52a heated by the heating means 5. The rapid cooling of the plastic material, i.e. the thermoplastic polymer of which the wires 51, 52 are made, guarantees greater compaction and stiffness of the plastic material after heating and deformation, i.e. after twisting about the working axis W. In addition, the rapid cooling carried out by the cooling means 12 also allows the joining substance (for example a glue) to be dried and consolidated so as to firmly and effectively fix the aforementioned wire portions 51a, 52a and the fibers 61 to each other.First cutting means 10 are provided downstream of the heating means 5 for cutting or shearing the portions 51a, 52a of the first and second wire 51, 52 at the end of the twisting process so as to obtain a brush 100 provided with a body 101 consisting of the two wire portions 51a, 52a twisted around each other along the longitudinal axis X so as to block the fiber bundle 60 (Figure 7).

[0037] The operation of the machine 1 for making brushes according to the invention, provides that the first and second unwinding means 21, 22 of the first feeding means 2 unwind the wires 51, 52 from the respective reels 55, 56 and arrange two wire portions 51a, 52a adjacent to each other and parallel to the working axis W inside the heating means 5 and in such a way that the ends 5 lb, 52b of the two wire portions 5 la, 5 la can be grasped by the gripper 10 of the gripping means 4 arranged in a first operating position Pl adjacent to the heating means 5. In particular, the two wire portions are inserted in the guiding grooves 8, 9 of the heating elements 6, 7 being rectilinear and parallel to the working axis W.

[0038] The heating elements 6, 7 are configured to heat the thermoplastic polymer of which the two wire portions 51a, 52a are made to the defined operating temperature Tw and by default heating time tr.

[0039] The gripper 40, once the ends 51b, 52b of the two wire portions 51a, 52a are grasped, is moved along and about the working axis W so as to progressively twist the wire portions 51a, 52a as they exit the heating elements 6, 7, moved by the unwinding means 21, 22. On the wire portions 51a, 52a entering the heating elements 6, 7, a joining substance, for example a glue, is also dispensed by the dispensing means 25, which allows the aforementioned wire portions 51a, 52a to be firmly fixed to each other.

[0040] Once a first section of appropriate length of the two wire portions 51a, 51 has been twisted (a section that will form the handle of the body 101 of the brush 100), the second feeding means 3 are activated so as to withdraw the fibers 61 from a magazine 15, form a substantially flat fiber bundle 60 and insert it between the two wire portions 51a, 52a while they are progressively moved inside the heating means 5, pushed by the unwinding means 21, 22 and pulled by the gripping means 4 along the working axis W. At the outlet of the heating elements 6, 7, the fibers 61 are blocked between the two twisted wire portions, also thanks to the joining substance dispensed by the dispensing means 25, and are arranged to form a substantially cylindrical bundle 60.

[0041] Alternatively, the dispensing means 25 may start dispensing the joining substance only when the fibers 61 reach the heating means 5.

[0042] Still alternatively, if the fixing means comprise welding means, in particular of the ultrasonictype, interposed between the first feeding means 2 and the heating means 5, the fibers 61 of the fiber bundle 60 are fixed, more precisely welded, to at least one of the wire portions 53 a, 53b before being inserted into the heating means 5.

[0043] The cooling means 12 previously activated, cool the two wire portions 51a, 52a previously heated by the heating means 5 and twisted. The rapid cooling of the plastic material, i.e. the thermoplastic polymer of which the wires 51, 52 are made, ensures the compaction and stiffness of the plastic material after heating and deformation. The cooling means 12 also allow the joining substance (for example a glue) to be dried and consolidated, so as to firmly and effectively fix the aforementioned wire portions 51a, 52a and the fibers 61 between them.

[0044] Once a second section of suitable length of the two wire portions 51a, 52a has been twisted, which blocks the bundle of bristles 60, i.e. once the body 101 of the brush 100 has been completed, the gripping means 4 are stopped in a second operating position P2 further away from the heating means 5 and the first cutting means 10 are driven so as to cut the portions 51a, 52a of the first and second wire 51, 52 and obtain a brush 100 which is released from the gripping means 4 and transferred by known and not illustrated movement means, in a subsequent operating station, for example a shaving station of the fiber bundle 60.

[0045] It should be noted that the predefined heating time tr depends on the physicochemical characteristics of the thermoplastic polymer and is obtained by appropriately setting the translation speed of the wire portions 51a, 52a along the working axis W, in particular during the crossing of the heating means 5 and by selecting the length of the guiding grooves 8, 9 of the heating elements 6, 7, which receive the two bent wire portions 51a, 52a.

[0046] The ends of the wire portions 51a, 52a protruding from the heating means 5 and generated by the cutting performed by the first cutting means 10 are then grasped by the gripping means 4 arranged in the first operating position Pl to make a subsequent brush 100 by repeating the operating steps described above.

[0047] Figures 8 and 9 illustrate a variant of the machine for making brushes according to the invention, which differs from the embodiment previously described and illustrated, in that it comprises second cutting means 11 arranged upstream of the first feeding means 2 for cutting a wire 50 made of plastic material that is unwound from a reel 57 so as to make wire sections 53 of a predefined length. This variant also differs for the first feeding means 2 which comprise third unwinding means 23 configured to unwind the wire 50 from the reel 57 and move one wire section 53 thereof at a time towards subsequent bending means 30. The bending means 30, in particular placed downstream of the second cutting means 11 withreference to a direction of movement of the wire 50, are configured to bend, in particular in the form of a "U", each wire section 53 made by the second cutting means 11 and obtain a bent wire section 53’ formed by two wire portions 53a, 53b, adjacent and parallel to the working axis W, having respective connected ends 53c or a common end (Figure 12). The bending means 30 comprise, for example, a first bending element 31 of known type, movable along the working axis X, in particular with reciprocating motion, so as to abut against and bend the wire section 53 at a median portion thereof.

[0048] The bending means 30 further comprises a first and a second guiding element 33, 34 cooperating with the first movable bending element 31 for bending the wire section 53. The first guiding element 33 and the second guiding element 34 are moveable along a driving direction K transverse, in particular orthogonal to the working axis W, toward each other to guide the wire section 53 while being bent by the bending element 31 so as to form the two wire portions 53 a, 53b bent and away from each other to allow movement of the bending element 31.

[0049] The heating means 5 comprise a first heating element 16 and a second heating element 17 also movable along the driving direction K between a working position L, in which they are adjacent and substantially abutting against each other to contact and heat the wire portions 53a, 53b, and a disengagement position D, in which the two heating elements 16, 17 are spaced apart from each other to allow the bending means 30 to act on the wire 50, in particular to allow the first bending element 31 to retract and bend the wire section 53 (Figure 8).

[0050] In the illustrated embodiment, the first heating element 16 also acts as a first guiding element 33 and the second heating element 17 acts as a second guiding element 34.

[0051] The first heating element 16 and the second heating element 17 comprise respective operating walls provided with guiding grooves 18, 19 arranged to receive and guide a respective wire portion 53 a, 53b to be heated.

[0052] As illustrated in particular in Figure 13, each guiding groove 18, 19 comprises a first portion 18a, 19a parallel to the driving direction K, a second portion 18b, 19b parallel to the working axis W and a third portion 18c, 19c interposed between the first portion 18a, 19a and the second portion 18b, 19b and having a curved shape.

[0053] As an alternative, in a variant of the machine not illustrated, the heating elements 16, 17 and the guiding elements 33, 34 can be distinguished and in any case connected in pairs to be moved between the working position L, in which the first guiding element 33 and the first heating element 16 are adjacent to and substantially abutting against the second guidingelement 34 and the second heating element 17 so as to guide and heat the wire portions 53a, 53b, and a disengagement position D, in which the first guiding element 33 and the first heating element 16 are spaced apart from the second guiding element 34 and the second heating element 17 to allow the bending means 30 to act on the wire 50, in particular to allow the first bending element 31 to retract and bend the wire section 53. In this case, each of the guiding elements 33, 34 comprises a first portion parallel to the driving direction K and a second portion parallel to the working axis W and a third curved portion interposed between the first and the second portion, while each heating element 16, 17 has an elongated shape and extends parallel to the working axis W.

[0054] The operation of this variant of the machine 1 provides that the third unwinding means 23 of the feeding means 2 unwind the wire 50 from the respective reel 57 and move it toward the bending means 30. The second cutting means 11 are arranged to cut the wire 50 so as to sequentially make wire sections 53, each of which is bent by the bending means 30 so as to obtain a bent wire section 53’ formed by two wire portions 53a, 53b having respective connected ends 53c. More precisely, the first bending element 31 is moved, for example along the working axis W so as to abut and bend the wire section 53 at a middle portion thereof in cooperation with the guiding elements 33, 34 coinciding with the heating elements 16, 17. The guiding elements 33, 34 (and heating elements 16, 17) are initially arranged spaced apart from each other along the driving direction K to allow the insertion of the first bending element 31 between them; they are then progressively brought closer along the direction K to cause the two wire portions 53a, 53b, bent over one another parallel to the working axis W, to abut against each other when the first bending element 31 is disengaged and moved away from the bent wire section 53’. In particular, in the working position L of the heating elements 16, 17 (and of the guiding elements 33, 34) the two wire portions 53a, 53b are completely bent and superimposed and the respective connected ends 53c or common end can be grasped by the gripping means 4 arranged in the first operating position Pl.

[0055] More precisely, the gripper 40, once the common end 53c of the two wire portions 53a, 53b is grasped, is moved along and about the working axis W so as to progressively twist the wire portions 53a, 53b as they exit the heating elements 16, 17, moved upstream of the third unwinding means 23 and downstream of the gripper 40. The heating elements 6, 7 are configured to heat the thermoplastic polymer of which the two wire portions 53 a, 53b are made to the defined operating temperature Tw for the defined heating time tr.

[0056] It should be noted that, also in this case, the heating time tr, which depends on thephysicochemical properties of the thermoplastic polymer, is obtained by selecting the speed of translation of the wire portions 53a, 53b along the working axis W, in particular during the crossing of the heating means 5, and the length of the guiding grooves 18, 19 of the heating elements 16, 17 that receive the aforementioned two bent wire portions 53a, 53b. On the wire portions 53a, 53b before they are inserted into the heating elements 16, 17, a joining substance, for example a glue, is dispensed by the dispensing means 25, which allows the aforementioned wire portions 53a, 53b and subsequently the fibers 61 to be firmly fixed to each other.

[0057] Once a first section of suitable length of the two wire portions 53 a, 53b has been twisted, the second feeding means 3 are activated so as to withdraw the fibers 61 from the magazine 15, form a substantially flat fiber bundle 60 and insert it between the two wire portions 53a, 53b while they are progressively moved inside the heating means 5 pushed by the third unwinding means 23 and pulled by the gripping means 4 along the working axis W. At the outlet of the heating elements 16, 17, the fibers 61 are blocked between the two twisted wire portions, also thanks to the joining substance dispensed by the dispensing means 25, and are arranged to form a substantially cylindrical bundle 60.

[0058] Alternatively, the dispensing means 25 may start dispensing the joining substance only when the fibers 61 reach the heating means 5.

[0059] The cooling means 12 previously activated, cool off the wire portions heated by the heating means 5 and twisted, ensuring greater compaction and stiffness of the plastic material after heating and deformation. The cooling means 12 also allow the joining substance (for example a glue) to be dried and consolidated, so as to firmly and effectively fix the aforementioned wire portions 53 a, 53b and the fibers 61 between them.

[0060] Once the two wire portions 53 a, 53b have been completely twisted so as to block the bundle of bristles 60 and make a brush 100, the gripping means 4 are stopped in the second operating position P2. The brush 100 is then released from the gripping means 4 and transferred by known movement means and not illustrated to a subsequent operating station, for example a fiber shaving station.

[0061] A subsequent wire section 53 is unwound from the third unwinding means 23 and arranged at the bending means 30 and the operating steps described above are repeated to make a new brush 100.

[0062] Figures 10 and 11 illustrate another variant of the machine for making brushes of the invention, which differs from the variant previously described and illustrated in Figures 8 and 9 for the bending means 30 comprising a second bending element 32 fixed to thegripping means 4 and arranged to engage the wire section 53. More precisely, the second bending element comprises a roller 32 fixed to one end of a hooking element 44 of the gripping means 4 and provided with a groove adapted to receive the wire 50. In this way, during operation, by means of the roller 32 the gripping means 4 in a first phase of a cycle of making the brush 100 in which they are moved only linearly along the working axis W, are able to hook, pull, bend a central portion of the wire section 53 and make a corresponding bent section 53’ formed by the two wire portions 53a, 53b joined at the common end 53c wrapped around the roller 32.

[0063] In a second step, the gripping means 4 are also moved in rotation about the working axis W so as to wind the two wire portions 53 a, 53b longitudinally and form the body 101 of the brush 100.

[0064] Also in this constructive variant, once a first section of appropriate length of the two wire portions 53 a, 53b has been twisted, the second feeding means 3 are activated to withdraw the fibers 61 from the magazine 15, form a substantially flat fiber bundle 60 and insert it between the two wire portions 53a, 53b while they are progressively moved inside the heating means 5 pushed by the third unwinding means 23 and pulled by the gripping means 4 along the working axis W. At the outlet of the heating elements 16, 17, the fibers 61 are blocked between the two twisted wire portions, also thanks to the joining substance, for example an adhesive, dispensed by the dispensing means 25, and are arranged to form a substantially cylindrical bundle 60.

[0065] The invention also relates to a method for making twisted wire brushes 100 comprising a body 101 formed by two portions 53a, 53b; 51a, 52a of at least one wire 50; 51, 52 made of plastic material twisted on each other along a longitudinal axis X so as to block a fiber bundle 60 inserted between them.

[0066] The method comprises the steps of:

[0067] - supplying and arranging two wire portions 53a, 53b; 51a, 52a at a time adjacent to and parallel to a working axis W ;

[0068] - grasping the ends 53c; 51b, 52b of the wire portions 53a, 53b; 51a, 52a and twisting the wire portions 53a, 53b on each other; 51a, 52a moving them along and about said working axis W in a twisted configuration A, in particular so as to obtain a first twisted section of the wire portions 53a, 53b; 51a, 52a;

[0069] - supplying a respective fiber bundle 60 and inserting it between the two wire portions 53 a, 53b; 51a, 52a and continuing to twist the wire portions 53a, 53b; 51a, 52a into the twisted configuration A so as to block the fiber bundle 60 between them, in particular to obtain asecond twisted section of said wire portions 53a, 53b; 51a, 52a that blocks the fiber bundle 60 and to make a brush 100;

[0070] - heating the wire portions 53a, 53b; 51a, 52a, while they are moved along the working axis W and before being twisted along and about the working axis W, at a defined operating temperature Tw for a defined heating time tr so as to make the wire portions 53a, 53b; 51a, 52a stiff and stable in the twisted configuration A, in particular after their cooling; and

[0071] - fixing the respective fiber bundle 60 to at least one of the wire portions 53a, 53b; 51a, 52a;

[0072] wherein it is further provided, before heating the wire portions 53a, 53b; 51a, 52a:

[0073] - to dispense on at least one of the wire portions 53a, 53b; 51a, 52a a joining substance that is suitable to fix the wire portions 53a, 53b; 51a, 52a and / or the fibers 61 of the fiber bundle 60 to each other; or

[0074] - to weld, in particular by ultrasonic welding, the wire portions 53a, 53b; 51a, 52a to the fibers 61 of the fiber bundle 60 or the fibers 61 of the fiber bundle 60 to at least one of the wire portions 53a, 53b; 51a, 52a.

[0075] In particular, the defined operating temperature Tw is between a lower operating temperature Twi and an upper operating temperature Tws, wherein the lower operating temperature Twi and the upper operating temperature Tws define an operating temperature range ATw that includes a glass transition temperature Tg of the plastic material of the wire portions 53a, 53b; 51a, 52a. The lower operating temperature Twi is e.g. about 20°C lower than the glass transition temperature Tg and the upper operating temperature Tws is about 45°C higher than the glass transition temperature Tg.

[0076] As is known, in a thermoplastic polymer at the glass transition temperature Tg the movements of the polymer chains that compose it are reduced and the material becomes compact and stiff, thus maintaining the shape assumed before heating. In the case in question, the wire portions 51a, 52a, twisted after their heating to an operating temperature Tw close to or in any case not far from, in particular less than about 15 °C, from the specific and respective glass transition temperature Tg for the defined heating time tr, maintain, once cooled to room temperature, the deformation undergone, that is, they remain substantially stiff and stable in the twisted configuration A.

[0077] The method further comprises, after the heating step, cooling off the wire portions 53a, 53b; 51a, 52a while they are twisted and moved along the working axis W in the twisted configuration A.The step of supplying and arranging two wire portions 51a, 52a at a time adjacent to and parallel to a working axis W comprises unwinding a first wire 51 made of plastic material from a first reel 55 and moving a respective portion 51a thereof at a time along the working axis W and unwinding a second wire 52 made of plastic material from a second reel 56 and moving a respective portion 52a thereof at a time along the working axis W.

[0078] The method comprises the step of cutting the wire portions 51a, 52a of the first wire 51 and the second wire 52 after the twisting step, i.e. in the twisted configuration A, to obtain a brush 100.

[0079] Alternatively, the step of supplying and arranging two wire portions 53 a, 53b at a time adjacent and parallel to a working axis W, comprises unwinding from a respective reel 57 and then cutting a wire 50 made of plastic material so as to obtain wire sections 53 of a predefined length and bending each wire section 53 so as to obtain a bent wire section 53’ formed by the two wire portions 53a, 53b having respective connected ends 53c or a common end.

[0080] The invention further comprises a twisted wire brush 100, comprising a body 101 formed by two portions 53a, 53b; 51a, 52a of at least one wire 50; 51, 52 made of plastic material, in particular of a thermoplastic polymer, twisted on each other along a longitudinal axis X so as to block a fiber bundle 60, in particular of plastic material, inserted between them, made with the machine 1 and / or the method described above.

[0081] The machine and method according to the invention therefore make it possible to make twisted wire brushes 100 using only plastic materials, thereby making them fully recyclable. More precisely, it is possible to make the body 101 of the brush 100 by twisting two portions of at least one wire of plastic material, in particular a thermoplastic polymer, one on top of the other along a longitudinal axis X in a twisted configuration A so as to block a fiber bundle 60 inserted between and made of the same plastic material or similar polymeric material. In this way it is possible to make a mono-material brush 100.

[0082] In particular, by heating the wire portions immediately before twisting them together at a defined operating temperature Tw, for example close to a glass transition temperature Tg of the plastic material of which they are made, for a predetermined heating time tr, it is possible to make said wire portions 53a, 53b; 51a, 52a stiff and stable in the twisted configuration A after their cooling, that is, to obtain a body 101 of the brush 100 that is substantially stiff and maintains stable shape and dimensions over time. In addition, the twisted wire portions, also by virtue of the joining substance, for example a glue dispensed or the welding performed, firmly block the fiber bundle that remains fixed to the body 101 of the brush 100.

Claims

CLAIMS1. Machine (1) for making twisted wire brushes (100) comprising a body (101) formed by two portions (53a, 53b; 51a, 52a) of at least one wire (50; 51, 52) made of plastic material, in particular a thermoplastic polymer, twisted on each other along a longitudinal axis (X) so as to block a fiber bundle (60) made of plastic material inserted between them, comprising:- first feeding means (2) for moving and / or arranging two wire portions (53a, 53b; 5 la, 52a) at a time adjacent to each other and parallel to a working axis (W);- second feeding means (3) for supplying and inserting between said two wire portions (53a, 53b; 51a, 52a) a respective fiber bundle (60);- gripping means (4) for grasping ends (53c; 5 lb, 52b) of said wire portions (53a, 53b; 51a, 52a) and movable along and about the working axis (W) to twist said wire portions (53a, 53b; 51a, 52a) on each other in a twisted configuration (A) so as to block the respective fiber bundle (60) between and form a brush (100); characterized in that it further comprises:- heating means (5) interposed between said first feeding means (2) and said gripping means (4) and configured to heat said wire portions (53a, 53b; 51a, 52a) at a defined operating temperature (Tw) for a defined heating time (tr) so as to make said wire portions (53a, 53b; 51a, 52a) stiff and stable in said twisted configuration (A) after their cooling; and- fixing means (25; 35) interposed between said first feeding means (2) and said gripping means (4) and configured to fix said respective fiber bundle (60) to at least one of said wire portions (53a, 53b; 51a, 52a).

2. Machine (1) according to claim 1, wherein said fixing means (25; 35) comprise dispensing means (25) interposed between said first feeding means (2) and said heating means (5) and arranged to dispense on at least one of the two wire portions (53a, 53b; 51a, 52a) entering the heating means (5), a joining substance that is suitable to fix together the two wire portions (53a, 53b; 51a, 52a) and / or the fibers (61) of said fiber bundle (60).

3. Machine (1) according to claim 1, wherein said fixing means (25; 35) comprise welding means (35), in particular of the ultrasonic type, interposed between said first feeding means (2) and said heating means (5) and arranged to weld together the two wire portions (53a, 53b; 51a, 52a) and the fibers (61) of said fiber bundle (60) or said fibers4. Machine (1) according to any one of the preceding claims, wherein said operating temperature (Tw) is between a lower operating temperature (Twi) and an upper operating temperature (Tws), said lower operating temperature (Twi) and said upper operating temperature (Tws) defining an operating temperature range (ATw) that includes a glass transition temperature (Tg) of the plastic material of said wire portions (53a, 53b; 51a, 52a).

5. Machine (1) according to claim 4, wherein said lower operating temperature (Twi) is 20°C lower than said glass transition temperature (Tg) and said upper operating temperature (Tws) is 45°C higher than said glass transition temperature (Tg).

6. Machine (1) according to any one of the preceding claims, wherein said heating means (5) comprise a first heating element (6; 16) and a second heating element (7; 17) arranged parallel and facing each other, each heating element (6, 7; 16, 17) comprising a respective operating wall provided with a guiding groove (8, 9; 18, 19) suitable for receiving and guiding along said working axis (W) a respective wire portion (53 a, 53b; 51a, 52a) to be heated.

7. Machine (1) according to claim 6, wherein said first heating element (6) and said second heating element (7) have an elongated shape and comprise guiding grooves (8, 9) rectilinear and parallel to said working axis (W).

8. Machine (1) according to any one of the preceding claims, wherein said first feeding means (2) comprise first unwinding means (21) for unwinding a first wire (51) made of plastic material from a first reel (55) and moving a respective portion (51a) thereof at a time towards said heating means (5) and second unwinding means (22) for unwinding a second wire (52) made of plastic material from a second reel (56) and moving a respective portion (52a) thereof at a time towards said heating means (5).

9. Machine (1) according to claim 8, comprising first cutting means (10) arranged downstream of said heating means (5) for cutting said portions (51a, 52a) of said first and second wire (51, 52) at the end of the twisting process so as to obtain a brush (100).

10. Machine (1) according to any one of claims 1 to 7, comprising second cutting means (11) arranged upstream of said first feeding means (2) and arranged to cut a wire (50) made of plastic material that is unwound from a reel (57) so as to make wire sections (53) of predefined length, said first feeding means (2) comprising unwinding means (23) for unwinding said wire (50) from the reel (57) and bending means (30) to bend each wire section (53) made by said second cutting means (11) and obtaining a bent wire section (53’) formed by two wire portions (53a, 53b) having respective connected ends(53c).

11. Machine (1) according to claim 10, when dependent on claim 6, wherein said first heating element (16) and said second heating element (17) are movable along a driving direction (K) transverse, in particular orthogonal to said working axis (W), between a working position (L) in which they are adjacent so as to abut against and heat said wire portions (53a, 53b) and a disengagement position (D) in which they are spaced apart from each other to allow said bending means (30) to bend said wire section (53).

12. Machine (1) according to claim 11, wherein said first heating element (16) and said second heating element (17) comprise respective operating walls provided with guiding grooves (18, 19) arranged to receive and guide a respective wire portion (53a, 53b) to be heated, each guiding groove (18, 19) comprising a first portion (18a, 19a) parallel to said driving direction (K), a second portion (18b, 19b) parallel to said working axis (W) and a third portion (18c, 19c) interposed between said first portion (18a, 19a) and said second portion (18b, 19b) and having a curved shape.

13. Machine (1) according to any one of the preceding claims, comprising cooling means (12) that are positioned downstream of said heating means (5), in particular on the opposite side with respect to said first feeding means (2), and arranged to cool said wire portions (53a, 53b; 51a, 52a) after being twisted by said gripping means (4) and while being moved out by said heating means (5), in particular said cooling means (12) comprising at least one nozzle (13) suitable for blowing air onto said wire portions (53a, 53b; 5 la, 52a).

14. Method for making twisted wire brushes (100) comprising a body (101) formed by two portions (53a, 53b; 51a, 52a) of at least one wire (50; 51, 52) made of plastic material twisted on each other along a longitudinal axis (X) so as to block a fiber bundle (60) made of plastic material inserted between them, comprising the steps of:- supplying and arranging two wire portions (53a, 53b; 51a, 52a) at a time adjacent to and parallel to a working axis (W);- grasping ends (53c; 51b, 52b) of said wire portions (53a, 53b; 51a, 52a) and twisting said wire portions (53a, 53b; 51a, 52a) on each other by moving them along and about said working axis (W) in a twisted configuration (A), in particular so as to obtain a first twisted section of said wire portions (53a, 53b; 51a, 52a);- supplying a respective fiber bundle (60) and inserting it between said wire portions (53a, 53b; 51a, 52a) and continuing to twist said wire portions (53a, 53b; 51a, 52a) on each other into said twisted configuration (A) so as to block the fiber bundle (60)between them, in particular to obtain a second twisted section of said wire portions (53a, 53b; 51a, 52a) that blocks the fiber bundle (60), and making a brush (100); - heating said wire portions (53a, 53b; 51a, 52a) while they are moved along said working axis (W) and, before being twisted along and about the working axis (W), at a defined operating temperature (Tw) for a defined heating time (tr) so as to make said wire portions (53a, 53b; 51a, 52a) stiff and stable in said twisted configuration (A) after their cooling;- fixing said respective fiber bundle (60) to at least one of said wire portions (53a, 53b; 51a, 52a);characterized by further comprising, before said heating, the step of:dispensing on at least one of said wire portions (53a, 53b; 51a, 52a) a joining substance that is suitable to fix the wire portions (53a, 53b; 51a, 52a) and / or the fibers (61) of said fiber bundle (60) to each other; orwelding, in particular by ultrasonic welding, said wire portions (53a, 53b; 51a, 52a) to said fibers (61) of said fiber bundle (60) or said fibers (61) of said fiber bundle (60) to at least one of said wire portions (53a, 53b; 51a, 52a).

15. Method according to claim 14, wherein said operating temperature (Tw) is between a lower operating temperature (Twi) and an upper operating temperature (Tws), said lower operating temperature (Twi) and said upper operating temperature (Tws) defining an operating temperature range (ATw) that includes a glass transition temperature (Tg) of the plastic material of said wire portions (53a, 53b; 51a, 52a), in particular said lower operating temperature (Twi) being 20°C lower than said glass transition temperature (Tg) and said upper operating temperature (Tws) being 45°C higher than said glass transition temperature (Tg).

16. Method according to claim 14 or 15, comprising after said heating, cooling off said wire portions (53a, 53b; 51a, 52a) while they are twisted and moved along said working axis (W) in the twisted configuration (A), in particular said cooling off comprising blowing air on said wire portions (53a, 53b; 51a, 52a).

17. Method according to any one of claims 14 to 16, wherein said supplying and arranging said two wire portions (53a, 53b; 51a, 52a) at a time comprises:- unwinding a first wire (51) made of plastic material from a first reel (55) and moving a respective portion (51a) thereof at a time along said working axis (W) and unwinding a second wire (52) made of plastic material from a second reel (56) and moving a respective portion (52a) thereof at a time along said working axis (W); or- unwinding, from a respective reel (57) and then cutting, a wire (50) made of plastic material so as to make wire sections (53) of predefined length and bend each wire section (53) so as to obtain a bent wire section (53 ’) formed by said two wire portions (53a, 53b) having respective connected ends (53c).

18. Method according to claim 17, comprising cutting said wire portions (51a, 52a) of said first and second wire (51, 52) after said twisting in order to obtain a brush (100).

19. Twisted wire brush (100) comprising a body (101) formed of two wire portions (53a, 53b; 51a, 52a) of at least one wire (50; 51, 52) made of plastic material, in particular a thermoplastic polymer, twisted on each other along a longitudinal axis (X) so as to block a bundle (60) of fibers (61) made of plastic material and inserted between them, made with the machine (1) according to any one of claims 1 to 13 and / or with the method according to any one of claims 14 to 18.

20. Brush (100) according to claim 19, wherein said at least one wire (50; 51, 52) and said fibers (61) of said fiber bundle (60) are made of the same plastic material.

Images