Buckles – buttons – clasps – etc. – Clasp – clip – support-clamp – or required component thereof – With specific mounting means for attaching to rigid or...
Reexamination Certificate
2000-02-07
2001-10-23
Sandy, Robert J. (Department: 3626)
Buckles, buttons, clasps, etc.
Clasp, clip, support-clamp, or required component thereof
With specific mounting means for attaching to rigid or...
C411S509000, C411S508000
Reexamination Certificate
active
06305055
ABSTRACT:
The invention relates to fasteners capable of being fixed to a panel such as a car bodywork sheet.
Such fasteners are already known which are provided, for fixing them, with a snapping-in foot to be pushed in through a hole in the panel with a predetermined diameter.
In particular, French certificate of addition 2.132.919 describes such a fastener whose snapping-in foot has a flat rigid web and two curved flexible flanges, the flat rigid web having two longitudinal edges converging towards a pointed end whilst the other end of the said web is connected to the remainder of the fastener, each curved flexible flange being connected to the web along a respective one of its two longitudinal edges and having, opposite a respective flat face of the said web, an internal surface bordered by this plane face of the web, by a longitudinal edge of this flange and by a transverse edge of this flange; the external surface of the snapping-in foot tapering respectively towards the pointed end and towards the transverse edge of the flanges, on each side of a change-of-direction plane oriented transversely to the axial direction of the foot, this external surface of the foot having, at the level of the change-of-direction plane, a roughly oval shape, the small width of which, corresponding to the diameter of the hole in the panel, is situated along the median axial plane of the web and the large width of which is situated along the axial plane oriented transversely to the median axial plane of the web.
When the snapping-in foot is pushed in through the hole in the panel, the cooperation between the periphery of the hole and the external surface of the foot has the effect that each flange, as long as it is in contact with the periphery of the hole through its insertion portion situated between the pointed end and the change-of-direction plane, flexes by elastic deformation towards the plane face of the web which faces the internal surface of this flange, the flanges thus flexing gradually as pushing in occurs until the moment when the insertion part of the flanges has passed through the hole, each of the flanges then expanding, the cooperation between the periphery of the hole and the external surface of the flange-retaining part situated between the change-of-direction plane and the transverse edge having the effect of driving the foot in the direction of pushing in until the remainder of the fastener is in abutment on the face of the panel situated on the insertion side, through a tapered sealing collar.
The invention aims to improve the performance of this type of fastener, and in particular to minimise the force required for inserting the snapping-in foot through the hole and to maximise the retaining force procured by the snapping-in foot in order to prevent the fastener from being pulled out.
To this end the invention proposes a fastener which is characterised in that the said internal surface of each flange is concave and in that the said longitudinal edge of each flange has, seen by an observer disposed parallel to the plane face of the web facing its internal surface, a V shape whose apex, directed outwards, is situated at the level of the said change-of-direction plane on each side of which the external surface of the foot tapers.
By virtue of these characteristics, it is possible to ensure that each flange deforms as well as possible, requiring, in order to flex towards the web, only a moderate force for pushing in the foot, and offering, during its elastic expansion, an excellent restoration of the energy stored during pushing in, by virtue of which it is possible to obtain high resistance to pulling out of the foot.
It should be noted in addition that the fastener according to the invention can be produced with less material than the above-mentioned prior fastener, whose flanges have an internal surface which is not concave.
According to preferred characteristics, each said flange is formed so as to flex towards the web so that at least a major part of the length of its said longitudinal edge comes into contact at the same moment with the plane face of the web.
Thus the material of each of the flanges is used particularly effectively since on the one hand it is avoided interfering with the flexion of the flange towards the plane face of the web by the premature coming into abutment on this face of a small portion of the longitudinal edge of the flange and since on the other hand each flange has, at each level of at least the major part of the length of its longitudinal edge, the maximum circumferential dimension compatible with the correct flexion towards the web.
According to preferred characteristics of use, notably for reasons of convenience in production, the said longitudinal edge of each flange is oriented in an oblique plane cutting the said plane face of the web which faces the internal surface of this flange, along a slanting line oriented, from the join between this plane face and the longitudinal edge of this flange, towards the said other end by means of which the said web is connected to the remainder of the fastener and towards the said longitudinal edge of the web along which this flange is connected, the angle between the said plane face and the said oblique plane being obtuse on the side of this flange.
According to other preferred characteristics, the insertion part of each flange, situated between the said pointed end and the said change-of-direction plane, has, over at least a major part of its circumferential direction, a thickness which is roughly constant along each axial plane.
Control of the way in which the insertion part of the flanges deforms during pushing in is thus particularly easy, since there is no variation in thickness in the axial direction.
According to other preferred characteristics, the said insertion part of each flange, situated between the said pointed end and the said change-of-direction plane, has a thickness which is greater along the longitudinal edge of the web to which this flange is connected than along the longitudinal edge of this flange.
The deformation of this insertion part of each flange, which is the one which is in contact with the periphery of the hole when the flange flexes towards the web, is easier, the closer to the longitudinal edge, so that the deformation is distributed along the circumferential direction of the flange, which demands relatively little force, and in any event less force than if this part of the flange were relatively rigid from its longitudinal edge to close to the web.
Preferably, for reasons of convenience of production and/or quality of results obtained:
the insertion part of each flange has, over at least a major part of its length, a thickness decreasing evenly towards the longitudinal edge of this flange; and/or
the insertion part of each flange has a longitudinal edge which is filiform over at least a major part of its length.
According to other preferred characteristics, the retaining part of each flange, situated between the said change-of-direction plane and the said transverse edge, has, over at least a major part of its circumferential direction, a thickness which is roughly constant along each axial plane.
Control of the way in which the retaining part of the flange is deformed during the pushing in and holding in place of the fastener, is thus particularly easy, since there is no variation in the thickness in the axial direction.
According to other preferred characteristics, the retaining part of each flange, situated between the said change-of-direction plane and the said transverse edge of each flange, has a lesser thickness along the longitudinal edge of the web to which this flange is connected than along the longitudinal edge of this flange.
The deformation of the retaining part of each flange is thus essentially of the type with tilting about the join between this part of the flange and the web, given that it is at this join that this part of the flange is the most flexible whilst it is close to its longitudinal edge that it is the most rigid.
Preferably, for reasons of convenienc
ITW de France
Lowe Hauptman & Gilman & Berner LLP
Sandy Robert J.
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