Device and packaging for precision brushing and combing and method and tool for obtaining same

Abstract

The invention proposes a precision brushing and combing device, allowing a top-quality, consistent, faultless and industrial implementation. To do this, the invention provides a geometrical bristle structure adjusted with precision distance-wise and angle-wise with respect to a reference, as well as dimension-wise, with mold implementation by wire spark erosion. In an example embodiment, the plastic-injection tool comprises at least one block assembly consisting of several steel plates, at least one row of cavities each intended to form the main portion of a bristle, machined either side of the surface separating two adjacent plates, and a closing-up element, disposed at the end of at least one row of cavities, in order to form the free end surface of the bristles. A space of calibrated thickness is made between the plates forming the main portion of the bristle and the plate or bar forming the free end surface of the bristle, so as to allow the air to escape at the time of the injection whilst avoiding leakage of plastic. An ejection mechanism is provided for extracting the device from the cavity after solidification of the plastic.

1 . A brushing or combing device molded by plastic injection comprising a plurality of bristles on a support, disposed according to geometrically regular patterns, each bristle having a base attached to the support, a flexible main portion extending on a longitudinal axis substantially orthogonal to the surface of the support at its anchorage point, and a free end, wherein the majority of bristles further comprising:
 a main portion defined geometrically by travel of a straight generator around the longitudinal axis, the distance between the generator and this axis being at any point less than 0.5 mm and the angle between the generator and the longitudinal axis being less than 2° at any position around said axis;   a free end defined by a transverse surface intersecting the longitudinal axis of the main portion; and   a total length lying between 1.5 and 15 mm.   
   
   
       2 . A brushing or combing device as claimed in  claim 1 , wherein all the bristles and at least part of the support are formed by injection of the same thermoplastic material into a metal mold. 
   
   
       3 . A brushing or combing device as claimed in  claim 1 , wherein the main portion has, in a cross-section transverse to the longitudinal axis, a geometrical shape chosen from amongst round, elliptical, rectangular, square, lozenge, cross and semicircular shapes. 
   
   
       4 . A brushing or combing device as claimed in  claim 1 , wherein the base connecting the main portion to the support comprises a portion of flared shape defined geometrically by the changing path of a straight or curved generator around the longitudinal axis of the main portion. 
   
   
       5 . A brushing or combing device as claimed in  claim 1 , wherein the free end of the bristle is defined by a plane surface that is perpendicular or inclined with respect to the axis of the main portion. 
   
   
       6 . A brushing or combing device as claimed in  claim 1 , wherein the free end of the bristle is defined by a curved surface with a cylindrical profile with an axis substantially perpendicular to the axis of the main portion. 
   
   
       7 . A brushing or combing device as claimed in  claim 1 , wherein at least some of the plurality of bristles is disposed in at least one row on the support, the axes of the main portions being substantially parallel and the distance between two adjacent bristles being substantially constant. 
   
   
       8 . A brushing or combing device as claimed in  claim 7 , wherein the bristles constituting a row have a length of main portion substantially different from that of the adjacent bristles of the same row, so that the free ends of the bristles lie on an inclined slope or a curve. 
   
   
       9 . A brushing or combing device as claimed in  claim 7 , wherein several rows of bristles are disposed parallel to one another to form at least one group of rows, all the free ends of the bristles forming a geometrically regular pattern. 
   
   
       10 . A brushing or combing device as claimed in  claim 9 , wherein at least one row has bristles having a main portion with a length greater than that of the bristles of some rows so that the free ends of this row go beyond those of the other rows. 
   
   
       11 . A brushing or combing device as claimed in  claim 9 , wherein at least one group comprises at least one row of bristles is disposed either side of the support. 
   
   
       12 . A brushing or combing device as claimed in  claim 7 , wherein several rows of bristles or groups of rows are disposed radially around a support of elongated shape. 
   
   
       13 . A brushing or combing device as claimed in  claim 1 , wherein the support of the plurality of bristles is secured to a gripping member chosen from amongst a handle, a haft and a rod. 
   
   
       14 . A brushing or combing device as claimed in  claim 13 , wherein the gripping member is connected to the support parallel to said support. 
   
   
       15 . A brushing or combing device as claimed in  claim 13 , wherein the gripping member is connected to the support perpendicular to said support. 
   
   
       16 . A brushing or combing device as claimed in  claim 1  any one of the preceding claims, wherein the main portion of at least some of the bristles comprises a reduction in thickness by tapering into a chamfer or point, made by removal of material. 
   
   
       17 . A brushing or combing device as claimed in  claim 1 , wherein the free end of at least some of the bristles comprises tips made by local melting of the thermoplastic material. 
   
   
       18 . A brushing or combing device as claimed in  claim 1 , wherein the support of the device is curved according to at least one radius of curvature, by application of a mechanical force after the molding operation. 
   
   
       19 . A plastic-injection tool capable of producing a brushing or combing device, the tool comprising at least one block assembly in which cavities capable of molding a plurality of bristles are hollowed out, wherein:
 the block assembly comprises several steel plates assembled permanently during use of the mold, and able to be dismantled periodically;   the block assembly comprises at least one row of cavities each intended to form the main portion of a bristle, machined either side of the surface separating two adjacent plates;   a closing-up element, in the form of a plate or bar, is disposed at the end of at least one row of cavities, in order to form the free end surface of the bristles;   a space of calibrated thickness, of between substantially 0.005 mm and 0.050 mm, is made between the plates forming the main portion of the bristle and the plate or bar forming the free end surface of the bristle, so as to allow the air present in the cavity to escape at the time of the injection whilst avoiding leakage of plastic; and   an ejection mechanism is provided for extracting the device from the cavity after solidification of the plastic by exerting pressure on the support parallel to the main axis of at least some of the plurality of bristles.   
   
   
       20 . A tool as claimed in  claim 19 , wherein the steel constituting the plates of the block assembly has great hardness, equal to or greater than 50 HRC after heat treatment, and wherein the machining of the plates is performed mainly by wire spark erosion. 
   
   
       21 . A tool as claimed in  claim 20 , wherein at least one row of cavities is machined by wire cutting through the same block of steel which is then sliced so as to obtain at least two plates, subsequently assembled. 
   
   
       22 . A tool as claimed in  claim 19 , wherein at least one block assembly is integrated in a steel casing comprising molding parts complementary to those of the block assembly in order to form a complete device with a support, a rod or a handle, and wherein it comprises an ejection system consisting of at least one pushing device situated along the edge of a row of bristles. 
   
   
       23 . A tapering method for a brushing or combing device, the tapering method comprising removing material from a side of a main portion of at least some bristles, progressively in order to form a point at a free end of these bristles. 
   
   
       24 . A tapering method as claimed in  claim 23 , wherein the material is removed mechanically by rubbing the bristles on an abrasive surface, a disk, an abrasive wheel or a band, while exerting sufficient force between the abrasive and the bristles in order to bend them progressively in at least one direction and thus expose part of the main portion to the removal of material. 
   
   
       25 . A tapering method as claimed in  claim 23 , wherein the material is removed chemically by dipping the end of at least some of the bristles in a liquid solvent capable of dissolving the plastic constituting said bristles, for a time sufficient to obtain a fine and progressive point, the dipping being followed by a rinsing operation in order to neutralize the chemical effects of the solvent. 
   
   
       26 . A burning method for a brushing or combing device, the burning method comprising exposing an end of at least some bristles to an intense heat source chosen from amongst a direct flame, blowing of hot air and an infrared radiation generator panel, until there is local melting of the thermoplastic material and formation of a tip at the end of each bristle. 
   
   
       27 . A curving method for a brushing or combing device the curving method comprising gripping a support of a plurality of bristles between two jaws so as to bend it beyond its elastic limit and thus retain a residual deformation. 
   
   
       28 . A curving method as claimed in  claim 27 , wherein the gripping operation is performed with a supply of thermal energy to the jaws. 
   
   
       29 . A curving method as claimed in  claim 27 , wherein the gripping operation is performed with a supply of ultrasound energy to the jaws. 
   
   
       30 . A brushing or combing device as claimed in  claim 1 , further comprising packaging for a hygiene, body care, make-up or pharmaceutical treatment product comprising the device, immersed in a liquid or semi-solid material intended to be applied on the skin, eyelashes or hair.