FR2651972A1 - PROTECTIVE ELEMENT FOR SHOE NEEDLE HEEL. - Google Patents

Abstract

According to the invention, the protective element or "butt" is constituted by a unitary assembly where are firmly linked together, in a homogeneous manner: a fixing means (1), nail or ankle for driving into the heel needle; a very hard resin molding (4) which traps the head (3) of the fixing means (1); an overmolding (5) around the hard resin (4) to constitute the wear plate of the tip made of relatively flexible plastic material and high resistance to abrasion.

Description

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  The present invention relates to the field of footwear and

  relates particularly to an element of protection against

  slip and anti-wear intended to be fixed to the free end of the heel of a woman's shoe and, specifically, of the so-called "needle" heel. Several types of such elements are already known in the field, often designated by the term "bonbout". The best known type of element consists of a simple block of synthetic plastic material of resistance to wear and to appropriate deformation, and which is pressed into the heel of a shoe using a metal fastening element such than a dowel, a tenon, a nail, etc ... To prevent the head of the metal fastening element from rubbing on the ground during the

  walking, it is known to provide in the wear block a reinforcement

  appropriate cement intended to receive said head, so that it cannot come into contact with the ground. However, as soon as a certain wear of the block has taken place, it is conceivable that the head of the fixing element is flush with the lower surface of the latter, thus disadvantageously damaging the soil and / or

generate unwanted noise.

  To overcome this drawback, we plan to drown the head

  of the fixing nail inside the protective element.

  However, such a solution leads to another drawback.

  Indeed, due to the inherent flexibility of the material of the element, it is understood that its attachment to the end of the heel using a hammer does not lead to assembly perfectly

  rigid which is desired, and it is frequent that this type of element

  must be replaced well before its degree of wear 1 '

  requires, for example due to premature separation of the as-

  semblance due to a malfunction, accidental shock, or

  again because of a marked phenomenon of punching of the element

  protection by the head of the nail which it shelters. We aknowledge

  also phenomena of resonance and sliding.

  Finally we often notice, after a certain time of use-

  sation, especially with narrow heels such as heels

  "needle" and the like, which the protective element can turn

  be free in relation to the heel. This is of course disadvantageous, both in terms of stability and

  shoe comfort only from an aesthetic point of view.

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  Many protection systems of the "bonbout" type have been recommended, marketed and / or have been the subject of a fairly large number of invention patents. We have certainly achieved elements of good robustness in use (see for example European patents Nos. 186 566 and 210 922) but all the patented improvements suggested so far have essentially concerned the means of connection or fixing of the block or wear plate at the heel of the shoe, by pegs, nails, studs or the like, it being understood that this wear plate was left to the appreciation of the manufacturer, who can exercise his choice in a large catalog of existing products currently on the market. It will be noted that, up to now, this wear plate is either contained in a bowl integral with the nail head (means of fixing to the heel) is maintained in

  place by this same head in the through position.

  It is essential to recall here the criteria which an "ideal" bonbout must satisfy, namely: - good resistance to abrasion of the wear plate in contact with the ground; - an absence of the above-mentioned punching phenomenon, due to premature wear of the head of the nail or other fixing means; - maximum resistance to pulling out, that is to say detachment from the nail and from the wear plate, the flexibility

  of the material of this plate causing it to tear

premature quitting.

  It is obvious that the same material used for the wear plate cannot meet these three requirements and the techniques used so far have only resulted in

more or less happy compromise.

  A solution has now been found to this problem of obtaining a high quality "bonbout" and good walking comfort, making it possible to fulfill the series of aforementioned requirements,

  apparently completely contradictory.

  According to the invention, the new protective element, of the type comprising a means of attachment to the heel or nail, of which

  the head is embedded in a block or wear plate, is essential-

  Lement characterized in that the head is molded in a first plastic material of high hardness which is integral with a second compatible plastic material, more flexible and resistant to abrasion, which acts as a plate

  wear, said head and the two materials constituting a

seems homogeneous and unitary.

  It will be understood that such an assembly, where the fastening means, or nail, and the wear plate are firmly secured, can combine the qualities sought for the most perfect "bonbout '" possible. Indeed, the imprisonment of the head of the

  nail in the very hard intermediate part (or first material

  riau) provides resistance to tearing and to deformation

  torsion and / or traction. Such molding also makes it possible to avoid, or in any case considerably delay the punching phenomenon. Finally, the "overmolding" around this hard material with a more flexible compatible plastic material, providing walking comfort, makes it possible to satisfy the condition of resistance to abrasion, by the choice of a material.

  good anti-wear characteristics.

  In practice, the first material must have sufficient hardness.

  fisante and preferably at least equal to 74 Shore D. It is advantageously chosen from plastics capable of being molded by injection such as for example - without limitation - polyamides or polyurethanes reinforced with a filler based on glass or other material appropriate. The second material is chosen, on the contrary, from flowable and heat-polymerizable plastics so as to produce, in a mold in which the head of the fixing means or nail has been injection molded, a perfect and homogeneous connection between the cast resin. and the hard part. This second plastic material

  may, for example, be constituted by a selected polyurethane

  rated for its high resistance to wear and abrasion.

  Protective elements embodiments, in accordance with the characteristics of the invention, are illustrated, without limitation, in Figures 1 to 3 of the accompanying sheet of drawings.

  These three figures represent a complete set of elements.

  protective type "bonbout" ready to be fixed, by the sharp part of the fixing means, in the stiletto heel of a

woman's shoe.

  The fastening means 1, constituted by a dowel with a can-

  grooves 2, is provided with an integral head 3 which has been trapped in the hard plastic material 4, advantageously by molding t4 2651972 by injection. Then, around this molding 4, an "overmolding" was carried out. 5 using a polymerizable resin giving

  resulting in a softer and more flexible material with good resistance

  abrasion resistance. This overmolding 5 constitutes the wear plate proper of the bonbout. As can be seen in FIG. 1, the resistance to punching of the element is provided by a surface of the hard molding 4 equal to that of the wear plate 5. On the

  Figures 2 and 3, on the contrary, which correspond to reali-

  bonbout stations for stilettos of small section, one

  more or less important part of the hard material 4 comes partial-

  in contact with the ground. For example, in Figure 3, the narrow extension 6 of the hard part 4 can serve as a wear indicator. In this way, a series of monoblock bonbouts were produced which were tested mechanically in the laboratory as well as in real conditions of prolonged walks. The hard material consisted of a glass-filled polyamide with a Shore D hardness of about 78 while the cast and overmolded material consisted

  in a polyurethane resin selected for its characteristics

  ticks of flexibility and its resistance to abrasion. Its hardness, around 90 Shore A, was much lower than that of the material

  hard. By operating in this way, for the majority of the samples,

  tillons experienced, tensile strengths (and therefore pullout) greater than 45 kg - considerably higher than those of the best bonbouts currently on the market - as well as resistance to wear or abrasion more than four times greater those obtained with the plates

known wear.

  Of course other variant embodiments, not shown

  felt in the drawings, can be implemented in the context of the invention. For example, the imaginary surface of separation or "line of demarcation" between the two plastic materials can be curved, instead of being straight as in FIG. 1 so as to provide a greater thickness of the wear plate 5 of the attack side of the foot on the ground. In addition, the wear indicator 6 of Figure 3 can be shaped differently and be provided in color to constitute a

easily identifiable landmark.

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R EV E ND I C A T I O N S

  1- Non-slip and anti-wear protective element for a shoe stiletto heel, of the type comprising a fixing means (1) to the heel, the head (3) of which is embedded in a wear block or plate, characterized in that said head is molded from a first material (4) of high hardness plastic, at least equal to 74 shore D,

  which forms a body with a second material (5) made of plas-

  compatible tick, more flexible and resistant to abrasion, with a hardness close to 90 shore A only, said material playing the role of wear plate; the head (3) of the fixing means (1) and the two materials (4,5) constituting a

homogeneous and unitary whole.

  2- element according to claim 1, characterized in that

  the first material (4) is chosen from plastics-

injection moldable ticks.

  3- element according to claim 21, characterized in that the plastic material consists of a polymer of polyamide or polyurethane type loaded with glass

  4- Element according to any one of claims 1 to

  3. characterized in that the second material (5) is chosen from flowable and polymerizable plastics / comp> atible with the first material (4). / hot - Element according to any one of claims 1 to

  4 characterized in that the space occupied by the first material

  riau (4) in which said head (3) is molded extends

  to come into contact with the ground, after the installation of said element

lying on the shoe heel.