Snap closure device

Abstract: A snap closure device (10), in particular for jewellery, costume jewellery trinkets and the like, comprising a body (12) with a hook part open on one side and a closing member (14) hinged onto the body. The closing member (14) has a closure part for closing the hook, a part for resiliently engaging on the body and an operating part, and it is movable between an open position, in which the hook part is open towards the outside, and a snap closed position, in which the closing member engages the body and closes the hook.

Description: The present invention relates to the field of closure devices with particular but not exclusive reference to the costume jewellery and jewellery fields and the like. At present various types of closure devices are used for fastening chains, necklaces and the like; one known closure device comprises a so-called "spring catch", having a hook which is opened and closed by means of a sliding pin which is spring urged into a closed position and held back manually in an open position against the action of the spring. The construction of such known devices involves problems, with consequently high production costs; the devices jam easily and have a relatively limited life mainly owing to the unpredictable life of the spring. FR-A-403448 discloses a snap closure device according to the preamble of claim 1 comprising: a body with a hook part, forming an opening on one side; a snap closing member comprising a part for closing the hook opening and an engaging means for coupling onto the body; the closing member being pivoted onto the body and rotable on it between an open position and a closed position. The body is made of resilient material with a U shape in side view and the possibility of elastically spreading apart the U-shaped arms is essential for the device operation, which otherwise could not be snap closed, being the closing member essentially rigid. So should the device itself be subjected to a certain traction, the body of the device will lengthen and/or the U arms will spread apart, what allows the accidental opening of the closing device. FR-A-2056481 discloses a snap closure device comprising: a body with a hook part, forming an opening on one side; a snap closing member comprising a part for closing the hook opening and an engaging means for coupling onto the body; the closing member being pivoted onto the body and rotatable on it between an open position and a closed position. The body is provided with a cleft in which the closing member is received; the closing member is made of a folded plate which has a sufficient inherent elasticity for the snap closure. It is however usual such folded plates lose their inherent elasticity in a short time, and break along the folding line. The aim of this invention is to realize a clasp for chains, necklaces and the like which is easy to produce, reliable, has a predictable life span and can be realized easily in different forms to suit different aesthetic requirements. These aims have been achieved with the device according to this invention, as claimed in claim 1. The new device is easy to construct and assemble and can be realized in different forms suitable for different styles. It does not jam, does not open accidentally and has a predictable useful life. The device is described below in greater detail with reference to the appended drawings, illustrating an embodiment which is merely exemplary and not restrictive, in which: figure 1 is a perspective view of a first embodiment of the closure device, in a closed condition; figure 2 is a perspective view of the device, similar to figure 1, but shown in an open condition; figure 3 is a side view of the device; figure 4 is a section along 4-4 of figure 3. The device which is the object of the invention is referenced as a whole by number 10 in the figures and comprises a body 12 and a closing member 14. The body 12 comprises an anchorage part 16 and hook part 18. The anchorage part generally comprises an anchorage slot 20 for the link of a chain; it could however have any other form whatsoever onto which the end of a chain, necklace, ring or the like could be welded or fixed in some other way. The hook part 18 is usually U-shaped or in the form of an open eyelet, with one side of the U forming an opening 21 and with a tooth 22 protruding slightly towards the outside from the free arm of the U. On the body 12 the closing member 14 is pivoted at 13 in such a way as to be pivotable around an axis a which is substantially orthogonal to the plane containing the hook 18. On the body 12 a means 24, like a projection or a recess is also provided, for snap locking of the closing member; there could be two of these means, one on each face of the body. Essentially the member 14 comprises a part which closes the opening 21 of the hook and a part which engages the snap locking means 24. The member 14 essentially has a double walled structure, extending along each face of the body 12, the parts being connected by at least one U-shaped portion. In the example in figure 1 to 4, the member 14 comprises two plates 14', 14'' which have thicker portions 27, in which is/are provided the cavity/cavities 29 for snap engaging the projection/s 24. The parts 27 are joined by a connection portion 28. When the device is closed, the portions 27 assume a position transverse to the hook 18 and preferably oblique with respect to the longitudinal axis of the device. It should be noted that preferably the fulcrum 13 is more or less on the theoretical extension of one side of the hook and the projection 24 on the theoretical extension of the other side of the hook, while the connection part 28 of the U in its closed position is above the tooth 22 and remains projecting beyond it and outwards from it. There are however other possible layouts. One foreseen but not restrictive use for the closure device is for fastening chains, for example for jewellery, costume jewellery trinkets and so on. One end of the chain is fixed to the anchorage part 16, by inserting a ring part into the slot 20 for example; the other end of the chain, ending in a ring, is inserted in the hook part 18. Then the closing member is rotated so as to close the opening 21. When the closing member is in the closed state and a force is applied to it directed to open it, on the connection part 28, the same can be considered as a lever, 13 being its fulcrum, the power being on 28 and the weight being at the engagement between the parts 29 on the body and 24 on the closing member. Therefore it is clear that, thanks to this combination, opening and closing require a certain effort. In particular, if a pulling action is applied to the two ends joined by means of the snap clasp, at first the hook resistance to tensile stress will resist the pulling action, and then, since the tooth 22 is present, the pulling force is partly discharged onto the pin 13. It should be noted that, although the closure device has been described as comprising two plates, it could however have only one. It could also consist of a shape with bars set at an angle to each other, U- or T-shaped for example, as long as it comprises a portion for closing the passage 21, a portion for snap engaging the engaging member, a tooth 22 and preferably a portion or part 27.

Claims: A snap closure device comprising: a body (12) including a hook part (18) with an opening (21) on one side, an anchorage part (16) and a snap engaging means (24); a closing member (14) comprising a part for closing the hook opening and an engaging means (29), for coupling onto the snap engaging means (24) of the body; the said closing member (14) being pivoted onto the said body and rotatable on it between an open position in which it leaves said opening (21) free and a closed position, in which it closes said opening (21), said closing member (14) embracing said body in the closed position, characterized in that the body comprises a tooth (22) projecting outwardly from the hook portion (18), which is adapted to engage said closing member (14) in its closed position upon oppositely directed pulling action on the hook part (18) and on the anchorage part (16). A device according to claim 1, characterized in that the closing member (14) comprises a U-shaped portion with arms extending on both faces of the body in said closed position, said arms of the U arranged transversely of the hook part in said closed position. A. device according to claim 2, wherein said arms of the U are arranged in a slanting position with respect to a longitudinal axis of the device when in the closing position. A device according to claim 1, wherein the pivot pin of the closing member and the engaging means lie along a line transverse to a longitudinal axis of the hook part. A device according to claim 1, wherein the pin of the closing member and the engaging member lie on a line parallel to or coincident with a longitudinal axis of the hook part.

Inventors: PIGNOTTI SANDRO, PIGNOTTI, SANDRO
Applicants: PIGNOTTI SANDRO, PIGNOTTI, SANDRO
Application year: 1990
Main classification: A44C11
IPC codes: F16B45, A44C5