Injection-moulded article comprising a field of hooks obtained by moulding

Patent metadata

Field	Value
Publication number	US-9937649-B2
Application number	US-201514919959-A
Country	US
Kind code	B2
Filing date	Oct 22, 2015
Priority date	Jul 1, 2008
Publication date	Apr 10, 2018
Grant date	Apr 10, 2018

Abstract

One-piece article obtained by injection molding, with at least one injection point, said article comprising a main body ( 20 ), having a body volume defined by the space within a surface forming an outer envelope, and at least one hook ( 21 ), preferably a field of hooks, obtained from the same molding of the main body of the molded article, the hook or each hook having a stem of longitudinal axis and a catching part projecting laterally from the stem, characterized in that the volume of the hooks is substantially smaller than the volume of the body, i.e. at least 100 times smaller, preferably at least 1000 times smaller, for example between 100 000 and 100 000 000 times smaller, than the volume of the body, and in that the width, or smallest transverse dimension, of the stems, measured transversely to the longitudinal axis, is smaller than the thickness of the main body, measured along the longitudinal axis of the stems.

First claim

What is claimed is:

1. A method for manufacturing by moulding of a moulded article comprising a field of hooks obtained integrally with part of an outer surface of the molded article, said method comprising the steps of
providing a moulding device comprising an inner closed surface which defines a main moulding chamber, at least one introduction opening for introducing thermoplastic moulding material into the moulding chamber, a field of cavities with a form complementary to hooks opening onto a first part of the inner surface, the first part of the inner surface being surrounded by an edge surface which does not comprise a cavity, and thrust means for thrusting at least a portion of the edge surface and an opposite part of the inner surface towards one another, the arrangement being such that the thrusting by the thrust means is limited, such that the edge surface and the opposite part which are thrust towards one another cannot come into complete contact with one another, a gap being thus formed between the edge surface and the opposite part, the gap being at least ten times smaller than the depth of the cavities with a form complementary to the hooks, and
injecting thermoplastic material via said introduction opening, in a single step of introduction.

2. The method of claim 1 , wherein the gap is between 0.01 and 0.1 mm, this gap being measured in the direction perpendicular to the edge surface and the opposite part which face each other, at the point(s) of the edge surface furthest away from the opposite part.

3. The method of claim 1 , wherein the gap is at least a hundred times smaller than the death of the cavities with a form complementary to the hooks.

4. The method of claim 1 , wherein the introduction opening opens into the moulding chamber at a part of the inner surface which does not comprise the opposite part.

5. The method of claim 1 , wherein the moulding chamber is devoid of any opening in the part of the inner surface opposite the first part and the edge surface.

6. The method of claim 1 , wherein the thrust means comprises at least one spring.

7. The method of claim 1 , wherein the thrust means comprises a hydraulic or pneumatic jack.

8. The method of claim 1 , comprising an insert block disposed in a detachable manner within the moulding cavity, the insert block comprising an upper surface forming a part of the inner surface of the mould, and the thrust means are integrated in the insert block.

9. The method of claim 8 , wherein a central part of the upper surface of the insert block forms the first part of the inner surface.

10. The method of claim 9 , wherein the edge surface is curved.

11. The method of claim 9 , where in the edge surface comprises a shoulder relative to the central part.

12. The method of claim 9 , wherein the edge surface comprises a curvature projecting relative to the central part, the thrust means thrusting the top of the curvature into contact with the opposite part.

13. The method of claim 9 , wherein protuberances project from the surface of the central part.

14. The method of claim 9 , wherein the edge surface is thrust by the thrust means, and the first part is secured relative to the opposite part and spaced from the latter.

15. The method of claim 9 , wherein the edge surface has a part which is eccentric.

16. The method of claim 1 , wherein the width, or smallest transverse dimension, of each cavity, measured transversely to the longitudinal axis thereof, is smaller than the largest height of the moulding chamber, measured along the longitudinal axis of the cavity.

17. The method of claim 1 , wherein the total volume of the cavities forming the field of cavities is at least 100 times smaller than the largest volume of the moulding chamber.

18. The method of claim 1 , wherein when the pressure of the thermoplastic material on the edge surface becomes sufficient to counter the force of the thrust means, the edge surface moves away from the opposite surface and the moulding material can penetrate within the gap.

19. The method of claim 1 , wherein once the hooks are formed, introduction of the thermoplastic material is stopped.

20. The method of claim 19 , wherein once introduction of the thermoplastic material is stopped, the thermoplastic material is allowed to cool, and the moulding device is opened in order to extract from the main chamber the final moulded article which comprises hooks on its outer surface.

21. A method for manufacturing by moulding of a moulded article comprising a field of hooks obtained integrally with part of an outer surface of the molded article, said method comprising the steps of
providing a moulding device which comprises an inner closed surface which defines a main moulding chamber, at least one introduction opening for introducing thermoplastic moulding material into the moulding chamber, a field of cavities with a form complementary to hooks opening onto a first part of the inner surface, the first part of the inner surface being surrounded by an edge surface which does not comprise a cavity, and thrust means for thrusting at least a portion of the edge surface and an opposite part of the inner surface towards one another, the arrangement being such that the thrusting by the thrust means is limited, such that the edge surface and the opposite part which are thrust towards one another cannot come into complete contact with one another, a gap being thus formed between the edge surface and the opposite part, the gap being dimensioned so that the moulding material cannot penetrate into the gap unless a pressure corresponding to a pressure which prevails when substantially all of the chamber filled with moulding material is applied to the gap, and
injecting thermoplastic material through said introduction opening, in a single step of introduction.

Assignees

• Aplix Sa

Inventors

• Mahe Anthony

Classifications

• B29C2045/5645

  Resilient compression means · CPC title

• Y10T428/24017

  Hook or barb · CPC title

• B29C45/372 Primary

  provided with means for marking or patterning, e.g. numbering articles · CPC title

• B29C45/561

  Injection-compression moulding · CPC title

• B29L2031/729

  Hook and loop-type fasteners · CPC title