DE102017130442A1 - Method and apparatus for making brushes - Google Patents

Abstract

A method and an apparatus for producing brushes provides that the back projecting filament ends (58) are heated and fused by a die, wherein the punch (54) not perpendicular to the top (42) of a bristle carrier (14), but a Relative movement between the punch and bristle carrier takes place with a transverse component.

Description

The invention relates to a method for producing brushes, comprising a brush holder having at least one opening and at least one bristle tuft of thermoplastic filaments seated in the opening. Moreover, the invention relates to a device for carrying out the method.

From the EP 1 136 017 B1 For example, a method and apparatus for fusing fiber ends of a bristle tuft are described. In this case, a heated punch is pressed against the rear side protruding filament ends to merge these ends together and at the same time reshape the heated mass, ie press it smooth. About this merging and reshaping all filaments are connected together, at least the filaments of a bristle tufts. If a plurality of bristle tufts are arranged next to one another, the mass of a tuft of bristles merges with that of the adjacent tufts of bristles, so that the tufts of bristles are also connected to one another, resulting in a plate-like connecting layer from which the filaments of the bristle tufts emerge. This reshaping of the heated mass also ensures that the filament ends are widened overall and are thus secured against being pulled out of the opening.

On the front side, the individual filaments should be arranged as compactly as possible side by side, above all, they should run parallel to each other, which is sometimes extremely difficult if the packing density, i. H. the cross-sectional density of the filaments is relatively low. In spite of a perforated plate usually present on the front side of the bristle carrier, into which the filaments penetrate on the front side and are positioned when they are fused together at the rear end, the filaments spread out a great deal after being pulled out of the perforated plate; this is referred to as "rebounding". "Fanning" or "popping" the tuft.

The object of the invention is to provide a method for producing brushes and an apparatus for carrying out the method in which this rebound is reduced and the parallelism of the filaments, just the outer filaments of a tuft of bristles to the rest of the tuft can be maintained within narrow limits ,

• Einsetzen des zumindest einen Borstenbüschels in die Öffnung, wobei die rückseitigen Filamentenden gegenüber einer Oberseite des Borstenträgers vorstehen, und

To solve this problem, the invention provides the following steps:

• Inserting the at least one bristle tuft into the opening, the rearward filament ends projecting from an upper surface of the bristle carrier, and

Heating and fusing the backside protruding filament ends by applying heat and applying a punch to the filament ends and reshaping the filament ends by the punch, wherein relative movement of the punch and the bristle carrier to each other takes place after contacting the punch and the filament ends, with a movement component laterally to the top in the area of the existing filament ends for applying a lateral force to the filaments of the existing bristle tufts.

So far, the stamps were always moved with their contact surface perpendicular to the top of the bristle carrier, whereby the filaments bulge each other and undirected and also pushed softened material between the filaments. In the method according to the invention it has been found that the tendency to rebound is significantly lower. The filaments are less biased against each other and axially compressed by oblique method of the punch at the rear end. This oblique component of the punch obviously ensures that the filaments are moved laterally toward one another and are thus layered rather than pushing against each other in an undefined manner. The tests carried out have shown that the significant quality improvement increases with the smaller thickness of the bristles and also with a decreasing density of the tuft. Straight thin bristles, however, and tufts with low filament density have shown major problems in the past to keep the filaments as parallel and exactly aligned as possible. The invention also brings great advantages in the use of sharpened filaments. With respect to the relative movement of the punch and bristle carrier is to emphasize that usually the punch is moved to the fixed bristle carrier, but also vice versa, the bristle carrier can be moved to the stationary punch or both parts can be moved and results in the relative movement.

Preferably, a relative movement between the punch and bristle carrier at an acute angle relative to the perpendicular to the top against the filament ends is brought about when the top is substantially planar, or
There is a sideways movement to the top in the area of all bristle tufts when it is arcuate. Even with these two alternatives, it depends on the relative movement of the punch and bristle carrier to each other and not necessarily on which of the two parts is moved. In a simple embodiment, the movement is carried out by an oblique movement of the punch or the bristle carrier. Alternatively, however, several movements with different directions of movement can be run through one after the other, For example, first a feed movement (relative movement) parallel to the extension of the filaments and then a movement perpendicular thereto.

The angle between the direction of movement of the stamp from hitting the back, projecting filaments (to the bottom dead center) and the perpendicular to the top of the bristle carrier should be a maximum of 70 °, in particular a maximum of 40 °, in particular a maximum of 30 °, preferably in the range of 10 ° are up to 30 °, as experiments have shown.

The heating and fusing can optionally be done, of course, with hot air or otherwise non-contact heat transfer. In this case, the stamp only ensures that the liquid or pasty mass of the individual filaments merges into one another and the filaments remain bundled and aligned next to each other.

However, the preferred embodiment provides that also the heating and fusing takes place by the punch, which in this case is heated when it contacts the filament ends.

This heating can be done by the stamp has an electric heater.

To release the stamp from the top of the bristle carrier can optionally be provided that the stamp is cooled rapidly, that is provided with a cooling device. This cooling device is, for example, a cooling water guide through the stamp.

The stamper is preferably moved back and forth along a path to and from the backside protruding filament ends.

The web is in particular linear, although it may also be provided that the web is an oval or a bow. For example, the punch could first be delivered vertically in the direction of the top of the bristle carrier during the initial movement, but then moved laterally just before, during and / or shortly after the contacting of the not yet melted filament ends.

The inventive method is particularly suitable for devices in which the at least one bristle tufts is transported by suction or a stream of compressed air into the opening. In such a supply of bristle tufts namely the tuft density is low in comparison to the so-called stuffing method in which bristle tufts are driven by a plunger mechanically into the opening.

The punch has a substantially flat contact surface, with which it is moved against the rear, projecting filament ends. During contact with the back, projecting filament ends, the contact surface extends substantially further parallel to the top of the bristle carrier, i. H. the contact surface is not pivoted. The top of the bristle carrier may at most be slightly curved, but this is negligible, because the difference in height between the side edges and a central region of the top is a maximum of a few tenths of a millimeter. In this context, the stamp could be carried out with its contact surface complementary. It is important that the top and the contact surface without inclination to each other, but are fed to each other parallel to each other, namely at the aforementioned acute angle.

If the bristle body has a substantially arcuate upper side, then the punch has a complementary contact surface with which it is moved against the rearwardly projecting filament ends, the contact surface extending substantially parallel to the upper side of the bristle carrier during contact with the rearwardly projecting filament ends.

The acute angle is always greater than 0 °, preferably greater than or equal to 10 °.

The bristle carrier is usually a part of the finished brush, i. H. It also consists of a thermoplastic material. In particular, the teaching of the invention can be carried out in so-called platelets, which then, after loading with bristle tufts z. B. be sprayed.

Of course, the method according to the invention can only be carried out for a single tuft of tufts, but numerous apertures which are filled with tufts of bristle are usually present in the bristle carrier. The stamp, which is moved at an acute angle to the vertical on the top, while welding all the filaments of the numerous bristle tufts together.

The invention further relates to a device for carrying out the method according to the invention, with a reciprocable punch, a receptacle for a bristle carrier provided with at least one opening, a transport device for bristle tufts, can be introduced with the bristle tufts in openings of bristle carriers the punch is movable along a guideway which extends at an acute angle relative to the perpendicular to the top of a carrier inserted into the receptacle. Because the top is usually horizontal is, the acute angle is also defined over the horizontal.

The punch can sit on a linear guide and be moved along it or, as previously stated, along a curved path or a circulating path.

Again, the angle is greater than 0 °, preferably greater than 10 °, with which the stamp is moved against the filament ends and this transforms.

As an upper limit it has been found that the punch is optionally moved at an angle of at most 70 °, but preferably at most 40 °, in particular at most 30 ° to the vertical and thus to the top of the bristle carrier. Angles in a range of 10 ° to 30 ° have proven to be optimal at present.

The stamp can, as I said, have a heating and / or active cooling.

In addition, the device may include a working with compressed air and / or vacuum transport device for bristle tufts, with which they are transported into the openings in the bristle carrier.

• - 1 eine schematische Draufsicht auf eine erfindungsgemäße Vorrichtung zur Durchführung des erfindungsgemäßen Verfahrens,
• - 2 eine schematische Schnittansicht durch die erfindungsgemäße Vorrichtung im Bereich der Schweißstation mit einem Stempel und einem Borstenträger,
• - 3 eine schematische Seitenansicht durch eine Vorrichtung im Bereich der Schweißstation mit einem Stempel mit bogenförmiger Kontaktfläche.

Further features and advantages of the invention will become apparent from the following description and from the following drawings, to which reference is made. In the drawings show:

• - 1 a schematic plan view of an apparatus according to the invention for carrying out the method according to the invention,
• - 2 a schematic sectional view through the device according to the invention in the region of the welding station with a punch and a bristle carrier,
• - 3 a schematic side view through a device in the region of the welding station with a punch with arcuate contact surface.

In 1 a device for producing brushes, in particular toothbrushes is shown, which comprises a plurality of stations.

The device has, for example, a cyclically rotating turntable 8th on or on the various vehicles 10 are attached, which successively pass through stations in cycles. The carriers 10 have so-called recordings 12 on, in particular upwardly open recesses, which are complementary to so-called bristle carriers 14 are. This bristle carrier 14 may be part of a later brush body and z. B. be designed as platelets or may be the entire brush body or run as a tool-side perforated field plates. Perforated field plates serve to first pick up bristle tufts in a specific pattern, which corresponds to the later hole pattern in the brush. After filling the perforated field plates, the bristle tufts are then transferred into the bristle carrier, which in turn is then part of the finished brush.

In a first station 16 is, as shown with an arrow, the recording 12 with the bristle carrier 14 Provided.

In the transport direction (clockwise direction) is followed by a filling station 18 in which the with openings 48 provided bristle carrier 14 filled with bristle tufts.

Optionally, for example, a cutting station below 20 be present, where the bristle ends to be fused are cut to the desired length before welding.

In a subsequent melting or welding station 22 The filament ends of the tufts are melted so that they are fused with the other filaments of a tuft of bristle or with all the bristle tufts of the brush. For this purpose, a corresponding heating device is provided, which will be explained below.

A completion station 24 , z. B. in the form of a spray station, may be part of the device, but this is not absolutely necessary. In the completion station 24 the stuffed bristle carriers are overmoulded, for example by injecting a neck and a handle of a toothbrush. However, if the bristle carrier is a tool-side perforated field plate, for example, in the injection station, a part or the entire brush body is molded onto the bristle tufts welded together. As previously indicated, a transfer of the bristle tufts from the perforated field plate to a bristle carrier may alternatively be effected beforehand.

The finished or at least partially finished brushes 26 are then removed from the device.

The transport of bristle tufts from a magazine 29 about a tuft singleton 30 to an optional intermediate magazine 32 and from there to the bristle carriers 14 takes place between the intermediate magazines 32 to the bristle carriers 14 via a transport device 34 that works with compressed air and / or vacuum. Bristle tufts are sucked or blown over hoses or tubes, as for example in the DE 20 2016 101 195 A1 is described.

In 2 is the welding station 22 shown schematically.

The bristle carrier 14 is in the present case a small plate, which forms part of the finished brush and which is later encapsulated. The bristle carrier has a bottom 40 as well as a top 42 , in sections through a depression 44 is formed, which from a circumferential edge 46 is surrounded. The top 42 is preferably flat, at most minimally arched.

The bristle carrier 14 has several openings, of which for simplicity only one opening 48 is shown. In this opening 48 is a tuft of bristles 50 consisting of numerous filaments inserted, which are made of thermoplastic material. In practice, all openings with the bristle tufts are usually before welding 50 stocked.

The top 42 at the same time forms the back of the bristle carrier 14 , Opposite the top 42 stand the bristle tufts 50 after insertion into the openings 48 something before.

From above is a heated (here by an electric heater 52 heated) stamp 54 against the backside protruding filament ends 56 hazards. If the stamp 54 with its flat contact surface 58 the back, protruding filament ends 56 contacted, is the stamp 54 at the contact surface 58 already hot, so the filament ends 56 melt and the filaments are joined together. The Stamp 54 then continues to the top 42 and compresses the liquid material into flat islands or to form one or more plates, so that filaments of a tuft of bristles and optionally also bristle tufts are connected to each other and materially merge into one another.

The movement of the stamp 54 to the top 42 takes place at an acute angle α to a vertical S of the top 42 ie it is a component of movement laterally to the top 42 in the field of filament ends 56 present, over which a lateral force is exerted on the filaments. Are several bristle tufts 50 in a bristle carrier 14 present, so there is a relative movement of stamp 54 to the top 42 such that all existing bristle tufts experience a lateral force.

In the embodiment shown, the web which is from the punch 54 is traversed, a linearly extending path, and the stamp thus moves obliquely downward and back up obliquely upward, when it is moved to its working and back to its original position. The movement of the punch is motorized, z. B. via a servo motor or a pneumatic cylinder.

The angle α is greater than 0 °, preferably greater than or equal to 10 °, a maximum of 40 °, in particular a maximum of 30 °.

In the preferred embodiment, the angle α is in the range of 10 ° to 30 °.

Preferably, the contact surface remains 58 always aligned during the lifting movement equal to the vertical S, preferably parallel to the top 42 ,

As an alternative to the linear path, of course, a curved path or a circumferential path can also be provided. It is important, however, that an oblique movement of the punch down occurs when the punch 54 on the filament ends 56 meets and continues to move to bottom dead center in its movement.

Alternatively, the stamp 54 also be provided with a cooling device, shown here by cooling channels 60 after the fusion of filament ends 56 to be passed through the water to the stamp 54 in the area of the contact surface 58 To cool as abruptly as possible, which then solidifies the just melted plastic material of the filaments.

As is usually the top 42 is in the vertical, the angle α is executed in this case also to the vertical.

The Stamp 54 is regarding his movement in the in 2 shown embodiment in a linear guide 62 movably mounted.

Has the bristle body 14 a substantially to the arcuate top 42 , please refer 3 so has the stamp 54 a complementary contact surface 58 , with which he against the back projecting filament ends 56 of several bristle tufts 50 is driven, with the contact surface 58 during contact with the backside protruding filament ends 56 all bristle tufts 50 essentially oblique to the top 42 of the bristle carrier in the area of all bristle tufts 50 runs, see arrow A , For all Bostenbüscheln 50 Thus, a force is introduced laterally by the punch, with which the filaments are pressed against one another laterally.

Of course, instead of moving the punch 54, only one movement of the bristle carrier 14 relative to the stationary punch may occur 54 taking into account the above parameters.

Instead of a linear movement, the relative movement between the punch 54 and bristle carrier 14 Of course, from small individual movements in different directions, for example, an initial longitudinal movement at the beginning of the contact of the stamp 54 with the filament ends 56 and then a movement in the transverse direction thereto. The aforesaid angle α is defined in such a stepped stepwise motion by the virtual line of contact of the position of the punch at the beginning of the contact of the filament ends and the position of the punch before returning to the home position, that is, when the molten material of the filament ends has been shifted to the maximum.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• EP 1136017 B1 [0002]
• DE 202016101195 A1 [0037]

Claims (17)

A method of making brushes comprising a bristle carrier (14) having at least one aperture (48) and at least one thermoplastic filament bristle tuft (50) disposed in the aperture, characterized by the steps of: inserting the at least one bristle tuft (50) into the aperture (48), wherein the backside filament ends (56) protrude from an upper surface (42) of the bristle carrier (14), and heating and fusing the backside projecting filament ends (56) by applying heat and applying a punch (54) to the filament ends (56) and forming the filament ends (56) by the punch (54), wherein a relative movement of the punch (54) and the bristle carrier (14) to each other after touching the punch (54) and the filament ends (56) takes place with a Movement component laterally to the top (42) in the region of the existing filament ends (56) for applying a lateral force on the filaments of or before bristle tufts (50). Method according to Claim 1 characterized in that the punch (54) is traversed against the filament ends (56) at an acute angle (a) relative to the perpendicular (S) on the top surface (42) when the top surface (42) is substantially planar, or under a sideways movement to the top (42) in the region of all bristle tufts (50) when this is arcuate. Method according to Claim 2 , characterized in that the angle (a) between the relative direction of movement of the punch (54) when hitting the back, projecting filament ends (56) and the perpendicular (S) to the top (42) of the bristle carrier (14) a maximum of 40 ° , in particular not more than 30 °, preferably in the range of 10 ° to 30 °. A method according to any one of the preceding claims, characterized in that the heating and fusing of the back filament ends (56) is effected by the die (54) which is heated when contacting the filament ends (56). Method according to Claim 4 , characterized in that the punch (54) is heated by an integrated electric heater (52). Method according to one of the preceding claims, characterized in that the punch (54) is provided with a cooling device, via which it can be cooled after the fusion of the filament ends (56). Method according to one of the preceding claims, characterized in that the punch (54) is moved back and forth along a path to and from the rearwardly projecting filament ends (56). Method according to Claim 7 , characterized in that the web is linear. Method according to one of the preceding claims, characterized in that the at least one bristle tufts (50) is transported by suction or a stream of compressed air into the opening (48). Method according to one of the preceding claims, characterized in that the punch (54) has a substantially planar contact surface (58), with which it is moved against the rearwardly projecting filament ends (56), wherein the contact surface during contact with the back projecting Filament ends (56) substantially parallel to the top (42) of the bristle carrier (14). Method according to one of Claims 1 to 9 , characterized in that the punch (54) has a substantially to the arcuate top surface (42) complementary contact surface (58), with which it is moved against the rearwardly projecting filament ends (56), wherein the contact surface (58) during contact with the back projecting filament ends (56) substantially parallel to the top (42) of the bristle carrier (14). Method according to one of the preceding claims, characterized in that the bristle carrier (14) is a part of the finished brush. Device for carrying out the method according to one of the preceding claims, comprising a reciprocating punch (54), a receptacle (12) for a bristle carrier (14) provided with at least one opening (48), a transport device (34) for tufts of bristles (34). 50), with which bristle tufts (50) can be introduced into openings (48) of bristle carriers (14), characterized in that the punch (54) is movable along a guideway which is at an acute angle (a) relative to the vertical ( S) on the upper side (42) of a bristle carrier (14) inserted into the receptacle extends. Device after Claim 13 , characterized in that the punch (54) is coupled to a linear guide (62) and is moved along this. Device after Claim 13 or 14 , characterized in that the punch (54) in an angle (a) of a maximum of 40 °, in particular a maximum of 30 °, preferably at an angle (a) is moved in the range of 10 ° to 30 ° to the vertical. Device according to one of Claims 13 to 15 , characterized in that the punch (54) has a heater (52) and / or an active cooling. Device according to one of Claims 13 to 16 , characterized in that a working with compressed air and / or vacuum transport device (34) is provided, are transported with the bristle tufts (50) in the openings (48).

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