Classifications

• • A—HUMAN NECESSITIES
  • A46—BRUSHWARE
  • A46B—BRUSHES
  • A46B9/00—Arrangements of the bristles in the brush body
  • A46B9/02—Position or arrangement of bristles in relation to surface of the brush body, e.g. inclined, in rows, in groups
  • A46B9/04—Arranged like in or for toothbrushes
• • A—HUMAN NECESSITIES
  • A46—BRUSHWARE
  • A46B—BRUSHES
  • A46B3/00—Brushes characterised by the way in which the bristles are fixed or joined in or on the brush body or carrier
  • A46B3/16—Brushes characterised by the way in which the bristles are fixed or joined in or on the brush body or carrier by wires or other anchoring means, specially for U-shaped bristle tufts
• • A—HUMAN NECESSITIES
  • A46—BRUSHWARE
  • A46D—MANUFACTURE OF BRUSHES
  • A46D3/00—Preparing, i.e. Manufacturing brush bodies
  • A46D3/04—Machines for inserting or fixing bristles in bodies
  • A46D3/042—Machines for inserting or fixing bristles in bodies for fixing bristles using an anchor or staple
• • A—HUMAN NECESSITIES
  • A46—BRUSHWARE
  • A46B—BRUSHES
  • A46B2200/00—Brushes characterized by their functions, uses or applications
  • A46B2200/10—For human or animal care
  • A46B2200/1066—Toothbrush for cleaning the teeth or dentures

Definitions

• the invention relates to a toothbrush with a brush head made of plastic with at least one folded bundle of bristles and at least one anchor plate made of plastic.
• the bristle bundles are attached to the brush body using metal anchor plates.
• These anchor plates are, for example, 3/10 mm wider than the hole diameter.
• the anchor plates are stuffed into the bristle bundle holes together with folded bristle bundles, whereby they dig into the brush body material with opposite outer edges and are thereby held.
• the known anchoring techniques are complex to produce and are not very reliable in fixing the bristle bundles.
• the object of the invention is to create a toothbrush belonging to the technical field mentioned at the beginning, which is easier to manufacture and ensures more reliable anchoring of the bristles.
• the solution to the problem is defined by the features of claim 1.
• the toothbrush according to the invention has a brush head made of plastic, at least one folded bundle of bristles and at least one anchor plate made of plastic.
• the brush head has a hole with a longitudinal axis and a hole cross section with a basic shape for receiving the folded bundle of bristles.
• an anchor plate is fixed in the hole.
• Two grooves running parallel to the longitudinal axis of the hole are held in a wall of the hole, which extend beyond the basic shape of the hole cross section (viewed perpendicular to the longitudinal axis) and which are formed by injection molding.
• the grooves form a U-shaped profile.
• the anchor plate is fixed in the two grooves in the U-shaped profile by welding.
• the grooves then have a combination section with a centering and tapering section at an entrance of the hole, which, viewed in a direction perpendicular to the longitudinal axis, has a depth and a width that gradually decrease as the distance from an entrance of the hole increases.
• the invention is based on the knowledge that without the combination section according to the invention it is not possible to anchor the plastic anchors sufficiently firmly (i.e. with a sufficiently high pull-out force) and sufficiently reliably (i.e. with sufficient consistency for each weld).
• the tests have shown that if the anchor plates are fed insufficiently symmetrically (e.g. due to a slight production-related offset between the grooves and the anchor plates), the anchor plates are either deformed when inserted into the holes and are therefore only partially welded, or that the welding only takes place in individual places because the contact between the edge of the anchor plate and three wall sides of the u-profile is insufficient at other points.
• significantly higher pull-out forces for the bristle clusters are achieved when anchor plates are welded to all three sides of a U-shaped groove.
• the longitudinal axis of the hole is perpendicular to a surface of the brush head.
• Several mutually parallel rows of holes at a short distance can be provided in the brush head.
• the hole (viewed transversely to its longitudinal axis) has a geometrically simple basic shape such as a circle, a rectangle or an ellipse.
• the grooves are embedded in the wall of the hole, i.e. they go beyond the basic shape of the hole cross section and extend into the volume material of the brush head.
• the grooves are already in the hole when the bristles and anchor plates are inserted. They are attached by injection molding, that is, during the injection molding production of the brush head.
• the wall is therefore preferably essentially the inner surface of a hollow cylinder or a rectangular or elliptical hollow profile, which is defined by the hole.
• the wall is therefore substantially parallel to the longitudinal axis of the hole.
• the grooves have a cross section (viewed perpendicular to the longitudinal axis of the hole) which is U-shaped. Because the grooves are embedded in the wall and are not, for example, placed on a rib that protrudes into the (free) hole cross section, the three wall sides of the u-profile are surrounded by volume material of the brush head. The material heating and softening that inevitably occurs when welding in the U-profile cannot therefore lead to the plastic material softening. The anchor plate is therefore reliably fixed both on the front side (bottom of the U-profile) and on the edge sides of the U-profile.
• the basic shape of the holes is circular or elliptical and is defined by the opposing grooves of a hole Alignment by an angle greater than zero, in particular 30° - 45°, offset from the direction of the row of holes (hole row direction of immediately adjacent holes). Because the basic shape is simple (circular, elliptical, rectangular or the like), that is, it is convex (i.e. has no indentations, such as ribs or inward projections) and the grooves are embedded in the wall, the hole cross section can be optimally adapted to that tufts of bristles to be inserted can be adjusted.
• the combination section forms, on the one hand, a centering section of the U-shaped profile. This tapers, viewed radially in relation to the longitudinal axis of the hole, to form the insertion area or insertion path for the anchor plate.
• the anchor plate is centered (e.g. with respect to the longitudinal axis of the hole) and on the other hand, when it is pushed in, the anchor plate is gradually fed to the area (called the “constant section” below) in which the anchor plate is finally fixed, whereby the anchor plate is connected to the plastic section of the U-profile of the grooves is essentially welded over the entire surface. .
• the grooves in the combination section also each have a taper section which, viewed in the direction perpendicular to the longitudinal axis, has a width which successively decreases as the distance from the entrance of the hole increases. This ensures that the anchor plate is fed symmetrically onto the two side walls of the u-profile in the constant section.
• the grooves Adjacent to the combination section, the grooves each have a constant section which, viewed in the direction perpendicular to the longitudinal axis, has a width and a depth which are constant along the longitudinal axis.
• the width and depth of the u-profile in the constant section is adapted to the width and thickness of the anchor plate.
• the U-profile in the hole is slightly less wide than the edge of the anchor plate and the distance between the two base surfaces of the opposing grooves is slightly less large than the width of the anchor plate.
• the combination section is designed simultaneously as a centering section and as a tapering section. This has the advantage that the anchor plate is centered and aligned over the shortest possible distance.
• the combination section is followed by the constant section.
• the depth decreases in two stages or in multiple stages.
• the centering section can have two or more linear or curved ones Have subsections whose angle with the longitudinal axis successively decreases with increasing distance from an entrance of the hole.
• the width decreases in two or more steps.
• the tapered section can have two or more linear or curved subsections, the angle of which with the longitudinal axis successively decreases as the distance from an entrance to the hole increases.
• the width of the grooves at the entrance to the combination area can be greater than a thickness of the anchor plate, specifically by at least 5% and a maximum of 100%. Such a widening of the groove facilitates the insertion and improves the symmetry of the load during friction welding in the constant section.
• the anchor plate is preferably rectangular. It can be particularly advantageous if it has no bevels on the narrow sides.
• the invention also relates to a method for producing a toothbrush with a brush head made of plastic and with at least one bundle of bristles anchored in the brush head, with the steps: a) providing a brush head with a hole for fixing the at least one bundle of bristles, a hole with a longitudinal axis and a Hole cross section with a basic shape for receiving the folded bundle of bristles, with two grooves running parallel to the longitudinal axis and extending beyond the basic shape of the hole cross section being formed by injection molding in a wall of the hole, the grooves then having a combination section with centering at an entrance of the hole.
• the grooves each have a constant section which, viewed in a direction perpendicular to the longitudinal axis, has a width and a depth which are constant along the longitudinal axis.
• Figure 1 is a perspective view of several rows of holes in a brush head
• Figure 2 is a perspective view of several rows of holes with an inserted anchor plate
• Figure 3 is a schematic sectional view of a hole with anchor plates capable of inserting a bundle of bristles into the hole, and a centering section and a constant section of the grooves;
• Figure 4 is a schematic top view of the hole shown in Figure 3;
• Figure 5 shows a schematic sectional view of the hole from Figures 3 and 4
• Anchor plate that folded the bristle bundle and inserted it into the hole
• Figure 6 is a schematic top view of the hole shown in Figure 5;
• Figure 7 is a schematic sectional view of a hole with grooves having a taper section, a centering section and a constant section;
• Figure 8 is a schematic top view of the hole shown in Figure 7. Ways of carrying out the invention
• Figure 1 shows a transparent brush head 1 of an embodiment of the toothbrush according to the invention.
• the embodiment has a plurality of circular cylindrical holes 5 in several rows.
• the basic shape of the hole in the longitudinal cross section is a circle. Folded bundles of bristles (not shown) and a corresponding number of anchor plates 3 made of plastic are inserted into the holes.
• the holes are preferably designed as blind holes in the one-piece brush head.
• the brush head 1 also has a hole 5 with a longitudinal axis L1 for each bundle of bristles.
• all holes 5 have the same longitudinal axis, namely perpendicular to the upper main surface of the brush head.
• the anchor plate 3 serves to anchor the respective bundle of bristles and is fixed in the hole 5.
• the longitudinal axis L1 is here exactly perpendicular to a surface 4 of the brush head.
• the hole 5 as such does not taper or widen, i.e. a cross section of the wall 6 is constant along the longitudinal axis L1 of the hole 5.
• the wall is essentially parallel to the longitudinal axis L1.
• Each hole now has two grooves 7 and 8, which are injection molded into the wall 6 of the hole 5 and are opposite one another and aligned parallel to the longitudinal axis L1, which are designed to accommodate the anchor plate 3.
• the grooves extend from the entrance of the hole 5 or from the surface 4 of the brush head to a depth in the lower half of the hole 5.
• the orientation of the pair of grooves of a hole does not run parallel to the row of holes, but is inclined at an angle of approximately 45° to the direction of the row of holes. This has the advantage that the grooves of adjacent holes are at a relatively large distance from one another.
• FIG 2 shows the view from Figure 1, with the exemplary anchor plate 3 being fixed here.
• the anchor plate is essentially rectangular. Preferably it has no bevels on the sides. This allows the anchor plate to be welded over a large area in the constant section of the grooves.
• the anchor plate 3 clamps between the grooves 7 and 8 in that the corresponding dimension of the anchor plate 3 is a certain amount higher than the distance between the bottoms of the grooves 7 and 8, at least in the end position of the anchor plate shown here.
• the anchor plate 3 is welded to the u-profiles of the grooves 7 and 8, for example by friction welding or by ultrasonic excitation of at least one of the components involved.
• Figure 4 is a top view of the hole 12 and Figure 3 is a section through the hole 12 in the plane S 1 .
• the groove has a centering section Z 1 in which the groove base runs obliquely to the longitudinal axis L2.
• the groove then has a constant section l ⁇ 1, in which the groove base runs parallel to the longitudinal axis L2.
• the fact can be used for clamping and/or welding that a depth T of the grooves 9 and 10, viewed along the longitudinal axis L2 and starting from the surface 13 or the entrance of the hole 12 into the brush head 14, is reduced and that when the anchor plate 15 is inserted, the anchor plate is fed symmetrically into the.
• the value of the depth T runs from the maximum T2 at the entrance of the hole to the minimum T1 at the end of the centering section Z1.
• the depth T of the groove is a distance value in a first plane S 1 /S2, which runs through the longitudinal axis L2 and perpendicularly through the two grooves.
• the width B 1 is a distance value in a second plane that runs perpendicular to the first plane.
• Both parts, bristle head 14 and anchor plate 15, are made of plastic, in particular of the same material, and both parts can be welded.
• the width B 1 in the combination section of the grooves is am Hole edge wider, in particular by at least 5% (eg maximum 10%), than the thickness D of the anchor plate 15. Where the combination section meets the constant section, the width of the combination section is the same width as the constant section.
• the grooves can be modified according to the embodiment shown in Figures 7 and 8 by also providing a tapered section V.
• Figure 7 is a view of section S3 marked in Figure 8. This embodiment shown here is based on the embodiment shown in Figures 1 and 2. Viewed in the direction S3, the depth gradually decreases.
• the width B of the grooves 16 and 17 also decreases successively with increasing distance from the entrance of the hole 20 on the surface 18 of the brush head 19. This additional taper causes the anchor plate (not shown here) to move into the grooves when it is inserted Biaxially centered and symmetrically loaded during friction welding insertion into the constant section.
• the centering section Z2 and the taper section V are here Both are designed in two stages, i.e. a first stage from the brush head surface 18 downwards tapers the groove at a first angle and a second stage following the first stage tapers the groove again, but at a second angle that is smaller than the first angle.
• a third phase (constant section l ⁇ 2) up to the offset of the grooves 16 and 17 is then, as shown, parallel to the longitudinal axis L3, but could also be designed obliquely.
• the narrowing of the depth of the groove could also be carried out in two or more stages.

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• Engineering & Computer Science (AREA)
• Manufacturing & Machinery (AREA)
• Brushes (AREA)

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• 2022
  • 2022-05-04 CH CH000524/2022A patent/CH719663A1/de unknown
• 2023
  • 2023-05-04 WO PCT/EP2023/061873 patent/WO2023213981A1/de not_active Ceased
  • 2023-05-04 EP EP23725958.5A patent/EP4518720B1/de active Active
  • 2023-05-04 US US18/861,659 patent/US20250325094A1/en active Pending
  • 2023-05-04 JP JP2024564670A patent/JP2025514458A/ja active Pending
  • 2023-05-04 CN CN202380038007.XA patent/CN119212587A/zh active Pending

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