Apparatus and method for securing a substrate to a plastic strip, and fastening device likely to be obtained by said method

Abstract

A method for assembling an assembly comprising a tape ( 100 ) of retaining elements and a substrate ( 200 ), said method comprising the following steps: a step of forming a tape of retaining elements by dispensing a molding material into a molding device ( 1 ), so as to form a tape ( 100 ) of retaining elements comprising a base ( 51 ) presenting a bottom face ( 511 ) and a top face ( 512 ), the top face ( 511 ) of the base ( 51 ) being provided with retaining elements; and a step of applying a substrate ( 200 ) against the bottom face ( 511 ) of the base ( 51 ) prior to said bottom face ( 512 ) of the base ( 51 ) solidifying in such a manner as to cause the substrate ( 200 ) to penetrate at least in part beyond a plane defined by the bottom face ( 511 ) of the base ( 51 ) of the tape ( 100 ).

1 .- 23 . (canceled) 
     
     
         24 . A retaining device comprising:
 a base extending in a longitudinal direction and presenting a top face and a bottom face;   a plurality of retaining elements extending from the top face of the base, each of the retaining elements being formed by a stem surmounted by a head, the stem having a bottom end connected to the base, and a top end opposite from the bottom end, the head surmounting the top end of the stem, and the head having a bottom face facing towards the base and a top face opposite from the bottom face;   the base presenting a thickness lying in the range 10 μm to 700 μm, where the thickness is a distance between the top face of the base and the bottom face of the base; and   wherein the retaining elements are arranged in a staggered or honeycomb arrangement.   
     
     
         25 . The retaining device of  claim 24 , wherein the base presents a thickness lying in the range of 10 μm to 100 μm, or in the range of 50 μm to 100 μm 
     
     
         26 . The retaining device of  claim 24 , wherein the head of each retaining element includes at least one catch portion that extends radially relative to the top end of the stem, and the at least one catch portion includes a downwardly sloping free end. 
     
     
         27 . The retaining device of  claim 24 , wherein the head presents a hexagonal shape. 
     
     
         28 . The retaining device of  claim 24 , wherein the stem of each retaining element presents symmetry of rotation about an axis perpendicular to the top face of the base. 
     
     
         29 . A method of forming a retaining device with hooks, wherein:
 a molding strip is provided that presents an inside face and an outside face, and that has a plurality of cavities, each cavity defining a stem extending from the outside face towards the inside face;   the molding strip is positioned on rotary drive means comprising at least two rollers, the inside face of the molding strip being arranged to bear against the drive means;   in a dispensing step, molding material is dispensed against the outside face of the molding strip by material dispenser means arranged facing the molding strip in such a manner as to define a gap between the material dispenser means and the molding strip, the step of dispensing the molding material being performed in such a manner as to fill said gap and the cavities with molding material so as to form a tape comprising a base of thickness that is defined by the gap, and first preforms projecting from said base each comprising at least a stem, the first preforms being formed by the molding material in the cavities of the molding strip;   in an unmolding step, the tape and the first preforms are unmolded; and   during a forming step, the unmolded tape is inserted in a forming device so as to modify shapes of the first preforms by forming,   wherein the preform comprises a rib that extends at least partially over an upper face of the preform, and the forming device modifies the shape of the preform, including the shape of the rib.   
     
     
         30 . The method of  claim 29 , wherein the forming device comprises an element at ambient temperature or at a non-regulated temperature, and at least one element at a temperature that lies strictly between a heat deflection temperature and a melting temperature of the molding material. 
     
     
         31 . The method of  claim 29 , wherein the molding strip is arranged on a periphery of a single roller. 
     
     
         32 . The method of  claim 29 , wherein a height of the rib as measured along a direction perpendicular to a plane of the base lies in the range 0.005 mm to 0.1 mm, or in the range 0.01 mm to 0.08 mm. 
     
     
         33 . The method of  claim 29 , wherein the molding material is polypropylene or a formulation based on polypropylene, and the dispensing step is performed at a pressure lying in the range 10 bar to 100 bar, or in the range 30 bar to 50 bar, and at a temperature lying in the range 150° C. to 300° C. 
     
     
         34 . The method of  claim 29 , wherein the first preforms are arranged in a staggered or honeycomb arrangement. 
     
     
         35 . The method of  claim 29 , wherein during unmolding, the strip and the first preforms are unmolded in such a manner as to deform the first preforms plastically so as to obtain second preforms of shapes that are different from the shapes of the first preforms, the second preforms each comprising a head, a height of the head of the second preform is increased by 5% to 100%, or by 12% to 50% relative to a height of the first preform, where the height is measured along a plane perpendicular to the plane of the base. 
     
     
         36 . The method of  claim 29 , wherein portions of the cavities forming the stems are generally frustoconical or circularly cylindrical in shape about an axis perpendicular to the outside face of the molding strip. 
     
     
         37 . The method of  claim 29 , wherein the molding strip comprises portions of the cavities forming heads that present a shape that is substantially frustoconical or hexahedral. 
     
     
         38 . The method of  claim 29 , wherein the stem of each preform presents symmetry of rotation about an axis that is perpendicular to a top face of the base. 
     
     
         39 . The method of  claim 29 , wherein each preform presents symmetry relative to a plane extending in a longitudinal direction of the base and containing the axis of the stem of the preform. 
     
     
         40 . The method of  claim 29 , wherein each preform presents a head, and the head of each preform includes at least one catch portion that extends radially relative to the top end of the stem, the at least one catch portion includes a downwardly sloping free end. 
     
     
         41 . The method of  claim 29 , wherein the molding material is polypropylene, and wherein during the forming step, at least one forming element of the forming device is maintained at a temperature lying in the range 75° C. to 165° C., or substantially equal to 120° C. 
     
     
         42 . The method of  claim 29 , wherein the preforms present a shape that is asymmetrical relative to a plane that is transverse to a longitudinal direction of the base. 
     
     
         43 . The method of  claim 29 , wherein the forming device modifies the shape of the preform, including the shape of the rib, by using a roller.