JEWELRY CLASP

Abstract: A jewelry clasp (10) having a base (12) and a cover (14) mounted on the base (12) for swinging movement and fea­ turing a pair of elongated resilient S-shaped friction tongs (28, 30) on the base (12) for snap-locking engagement within el­ ongated grooves (40, 42) of a pair of complementary resilient friction flanges (32, 34) on the cover (14) for releasably secur­ ing the base (12) and its cover (14) in locked position.

Description: This invention generally relates to jewelry clasps and more particularly concerns jewelry clasps of a type including a base and swinging cover supported on the base for movement between an open position and a locked position. Jewelry clasps are used for interconnecting free ends of necklaces, chains, bracelets and similar type jewelry. To effect longer lasting usage, a variety of different approaches have been used as evidenced by the prior art. Normally, the locking of a jewelry clasp is delicate in nature and subject to seemingly incompatible objectives of providing security in a relatively small aesthetically pleasing construction. A principal object of this invention is to provide a new and improved jewelry clasp which is structurally and functionally superior to known clasps and jewelry catches. Related to this object is the aim of providing such a clasp which not only securely locks free ends of an attachable jewelry device but effects such a locking function in a clasp featuring simplicity of design and integrity of function. Another object of this invention is to provide a clasp of the above described type which is economical to manufacture, comprised a minimum number of parts and is quick and easy to use repeatedly and reliably over an extended period of time. US-A-1754959 discloses a jewelry clasp having a body, an outer locking bar or cover that is hinged to the body at one end and the free end of which has a tooth that can snap into a notch in the other end of the body, and an inner locking bar that is hinged to the body near the said one end and the free end of which snaps into a notch in a pin projecting from the base. One end of a bracelet is fastened to the said other end of the body, and in use the other end of the bracelet is seated in a recess in the middle of the body and both of the locking bars are closed over it. US-A-2462425 discloses a clasp for linking together two parallel bands, with a body having a long branch and a short branch, between which one band is captive. A locking element is hinged to the free end of the short branch, and has a nose that snaps over a lip on the free end of the long branch, the second band being held between the long branch of the body and the locking element. US Patent no. 4314389, on which the preamble of claim 1 is based, discloses a jewelry clasp comprising a body, a clamp plate one end of which is hinged to one end of the body and the other end of which is fastened to a chain or the like, and a lock plate one end of which is pivoted to a middle portion of the clamp plate by means of a pair of projecting lugs on the lock plate that are received in upstanding eyes on the clamp plate. In use, a second chain or the like is placed over the clamp plate between the other two plates, the lock plate is pivoted down over the chain and clips over the hinge joining the body to the clamp plate, and the body is then hinged down over the lock plate and clamp plate, until a pair of projecting eyes on the body clip over the ends of the lugs on the lock plate. The invention provides a jewelry clasp (10) comprising a base member (12), a cover member (14) supported on the base member for swinging movement about a pivot axis (A) between an open position and a locked position, the base and cover members (12, 14) each having a pair of elongate locking tongs (28, 30; 32, 34) extending transversely to the said axis (A), each interengageable with a corresponding one of the tongs of the other member, the cover tongs (32, 34) each being integrally formed with and depending from the cover member (14) and the base tongs (28, 30) each being integrally formed with and upstanding from the base member (12), characterised in that each of the cover tongs (32, 34) includes an elongate locking groove (40, 42) extending transversely to the said axis (A), and each of the base tongs (28, 32) is of generally S-shaped cross-section including a convex curved wall portion that defines an elongate off-set shoulder (36, 38) registrable with the locking groove (40, 42) of the corresponding cover tong (32, 34) in direct surface-to-surface area contact for releasably securing the base and cover members (12, 14) in the locked position. One form of jewelry clasp constructed in accordance with the invention will now be described by way of example with reference to the accompanying drawings, in which: Fig. 1 is a plan view of a base of a clasp of this invention; Fig. 2 is an end view of the base of Fig. 1; Fig. 3 is a side view of the base of Fig. 1; Fig. 4 is a cross-sectional view, taken generally along line 4-4 of Fig. 3; Fig. 5 is a side view of a cover of a clasp of this invention; Fig. 6 is an end view of the cover of Fig. 5; Fig. 7 is a bottom plan view of the cover of Fig. 5; Fig. 8 is a side view showing the base and cover of the clasp of this invention in assembled relation; Fig. 9 is a cross-sectional view, taken generally along line 9-9 of FIG. 8, with certain parts deleted for purposes of clarity; and Fig. 10 is a bottom plan view of the assembled clasp of FIG. 8. Referring in detail to the drawings, a jewelry clasp of this invention is generally indicated by numeral 10 and comprises an elongated base 12 and cover 14 wherein cover 14 is supported on base 12 for swinging movement about a pivot axis A (FIG. 10) between an open position (not shown) and a locked position (FIG. 8). In locked position, the clasp 10 will be understood to secure attachable free end links B and C of a jewelry device in first and second openings 15 and 22 (FIG. 8). More specifically, base 12 includes a base plate 16 of generally rectangular configuration having a coiled end or eye 18 at one end and a laterally extending cross-bar 20 at an opposite end of plate 16. Eye 18 of the base plate 16 forms the above mentioned laterally extending opening 22 which engages a free end link C of a chain, necklace, bracelet or the like, not shown. The base plate 16 further includes a pair of upright side walls 24, 26 on opposite lateral sides of the plate 16 and upstanding resilient friction tongs 28, 30 which project upwardly midway along the length of each base side wall 24, 26. In accordance with the teachings of this invention, each of the upstanding friction tongs 28, 30 is particularly suited to provide significantly increased surface-to-surface contact engagement with corresponding elongated friction tongs or flanges 32, 34 formed on the cover 14. More specifically, the friction tongs 28, 30 are each of serpentine or generally S-shaped cross-section in mirror-image relation to one another (FIGS. 4 and 9) and include an off-set shoulder 36, 38 for mating registration with a longitudinally extending, complementary recessed locking groove 40, 42 (FIG. 6) on an elongated inner face 44, 46 of each of the depending elongated resilient friction flanges 32, 34 extending downwardly from opposed side walls 48, 50 of the swinging cover 14. The longitudinally extending recessed locking grooves 40, 42 are best seen in FIGS. 6 and 7. The inner face 44, 46 of each depending friction flange 32, 34 is particularly suited to fully engage the off-set shoulder 36, 38 (FIG. 9) of each friction tong 28, 30 when the base 12 and cover 14 are assembled and snapped into locked position (FIG. 8). By virtue of the above described construction, the base 12 and cover 14 are each formed as relatively simple parts of one-piece construction, and significantly increased surface-to-surface area contact is obtained between the complementary base and cover tongs. This structure is in sharp contrast to that of known prior art devices and significantly increases the effectiveness of the locking mechanism, its usability over extended periods of time and its reliability and wearability of the product with which the clasp 10 is associated. To effect a clasp 10 of structural integrity and simplicity of design thereby to minimize manufacturing cost and further enhance wearability and usage, the base 12 features a pair of fingers 52, 54 projecting in opposite lateral directions from ends of cross bar 20 and which jointly define pivot axis A for swinging cover 14 upon mounting fingers 52, 54 in mating openings 56, 58 respectively formed in a pair of ears 62, 64 depending from cover 14 adjacent its end wall 60.

Claims: 1. A jewelry clasp comprising a base member, a cover member supported on the base member for swinging movement about a pivot axis between an open position and a locked position, the base and cover members each having a pair of elongate locking tongs extending transversely to the said axis, each interengageable with a corresponding one of the tongs of the other member, the cover tongs each being integrally formed with and depending from the cover member and the base tongs each being integrally formed with and upstanding from the base member, characterised in that each of the cover tongs includes an elongate locking groove extending transversely to the said axis, and each of the base tongs is of generally S-shaped cross-section including a convex curved wall portion that defines an elongate off-set shoulder registrable with the locking groove of the corresponding cover tong in direct surface-to-surface area contact for releasably securing the base and cover members in the locked position. 2. A clasp as claimed in claim 1, including projections formed on one of the said base and cover members, the other of the said base and cover members including a pair of projection-receiving openings and supporting the projections for rotation, whereby the cover member is supported on the base member for swinging movement about the pivot axis defined by the projections. 3. A clasp as claimed in claim 2, wherein the projections comprise a pair of fingers integrally formed on the base member to extend in opposite directions from an end wall of the base member, and wherein the cover member includes a pair of depending ears each having an opening formed therein for receiving a respective one of the fingers. 4. A clasp as claimed in claim 3, wherein the base member includes an elongate rectangular plate having a coiled end defining a laterally extending eye and an opposite end defining a cross-bar in upstanding relation to the plate and extending laterally of the plate, opposite ends of the cross-bar having the said fingers extending in opposite directions. 5. A clasp as claimed in claim 4, wherein the cover member includes a swinging free end, the swinging free end in the locked position being in overlapping relation to the coiled end of the base member. 6. A clasp as claimed in claim 4 or claim 5, wherein the base and cover members in the locked position jointly define a first attachable link opening for the clasp, and wherein the coiled end of the base member defines a second attachable link opening for the clasp. 7. A clasp as claimed in any one of claims 1 to 6, wherein the base member is of a generally elongate configuration, wherein the said tongs of generally S-shaped cross-section are formed one on each side of the base member, wherein the cover member is elongate, and wherein the tongs including the elongate locking grooves are formed one on each side of the cover member. 8. A clasp as claimed in any one of claims 1 to 7, wherein the cover tongs extend in lapping relation to the base tongs in the locked position. 9. A clasp as claimed in claim 8, wherein each of the cover tongs has a substantially smooth uninterrupted outer face in lapping relation to the corresponding one of the base tongs in the said locked position. 10. A clasp as claimed in claim 8 or claim 9, wherein the complementary tongs of the base and cover members are each formed of a suitable resilient material to effect snap-locking engagement for releasably securing the base and cover members in the locked position.

Inventors: ZIEMELIS, HERBERT
Applicants: THE NAPIER CO:
Application year: 1988
Main classification: F16G15
IPC codes: A44C5, A44C25, F16G15