EP0950364A1

EP0950364A1 - Link pin for flexible bracelet

Info

Publication number: EP0950364A1
Application number: EP98107024A
Authority: EP
Original assignee: Novotech SA
Current assignee: Novotech SA
Priority date: 1998-04-17
Filing date: 1998-04-17
Publication date: 1999-10-20

Abstract

A link pin (2) for a watch bracelet is secured on a lateral link (1) by a locking piece (6) comprising a finger (4), the locking piece (6) being soldered in a casing (13) of the link (1).

Description

The present invention concerns link pins for flexible bracelets, particularly for watches, according to the preamble of claim 1.
Bracelets are made flexible, in a known manner, by interconnection of links around pins, such pins serving as axes for relative rotation of links.
In order to avoid dismantling of bracelets, pins are secured by various means including soldering to the lateral links.
Shocks, severe temperature conditions combined with the action of chemicals, e.g. chemicals contained in the sweat of the wrist wearing the bracelet, have always caused unwanted disruptions, the pin being disassembled from a lateral link. A bracelet being formed of a succession of lateral and central links, interconnected around numerous pins, a expensive watch can be lost by its owner if only one pin is accidentally caused to be extracted from one of the lateral links.
Patent CH 664 267 teaches to secure pins to bracelet links by means of locking pieces snapped into recesses made in the pins. However, the system proposed has the disadvantage of dangerously splitting the link, creating a weak point, as well as a high manufacturing cost. An economical way to unreleasably securing a pin to a lateral link of a bracelet was therefore still to be found.
The present invention proposes to solve this problem by the means described in the characterizing part of claim 1. According to the invention, the locking piece cooperates with a recess that is located on at least one end of the pin.
In a particular embodiment of the invention, two similar recesses are located each on one end of the pin, these ends being secured to two lateral links of the bracelet, thanks to correspondingly similar locking pieces. In such an embodiment, the pin goes through a plurality of links and serves as an axis to their relative rotation. In particular, there can be one or several inner links, called central links, in addition to the two lateral links which form the ridges of the bracelet.
In a particular embodiment of the invention, in order to facilitate the bracelet assembly, the lateral link is provided with a casing that is adapted to secure the end of the pin, a tapered portion providing guidance of the end of the pin into such casing. In this embodiment, the pin has a split end to provide some flexibility to the tapered portion when the pin is mounted. When the tapered portion has snapped into the casing, the split end recovers its normal shape, allowing introduction of the locking piece into the casing and into the split end of the pin. Advantageously, in this embodiment the locking piece has a shape that allows to introduce it into the casing from a lateral side opposed to the pin, its shape comprising a finger that fits into the split end of the pin.
When the locking piece is introduced, preferably with friction, into the casing, its finger locks the split end, preventing any accidental retraction of the pin's end out of the casing. The locking piece is then secured in its turn to the link by known means. These means include thrusting the locking piece, which can be of a slightly conical shape or of a cylindrical shape, into the casing with a high force, the external dimensions of the locking piece being slightly larger than the inner dimensions of the casing. They further include cutting complementary threads in a cylindrical portion of the locking piece, and in a corresponding cylindrical portion of the casing. The locking piece can then be tightened into place by a high screwing couple. The means also include soldering the locking piece's external surface to the neighboring surface of the casing.
It will be readily understood that in the case of removable links that allow to modify the length of the bracelet to adapt it to the wearer's wrist, the locking piece is removably secured to the link. On the contrary, for links not designed for length adaptation, the finishing operations will preferably entail the removal of any clue of the presence of a locking piece in the casing of the link.
In a particular embodiment of the invention, the end of the pin is machined by a saw or a similar cutting tool. The excavation left by such tool is preferably limited by two planes, parallel to the pin's axis.
In a particular embodiment of the invention, the said cutting tool cuts two excavations as described in the previous embodiment. The second excavation is limited by two planes that are preferably perpendicular to the planes limiting the first excavation.
In this embodiment, the pin ends in four legs, and the finger of the locking piece preferably has a complementary form to firmly prevent any movement of the legs terminating the pin's end.
In a particular embodiment of the invention, cutting tools cut a plurality of excavations in the pin's end.
In a particular embodiment of the invention in which two recesses are located on both ends of the pin, the pin is placed into a hollow cylindrical sheath prior to its mounting into the links. Preferably, the inner diameter of the sheath and the outer diameter of the body of the pin are such that the body of the pin fits snugly into the sheath. The length of the sheath corresponds to the total width of the central links; as a result, if the diameter of the casing in the lateral link is smaller that the outer diameter of the sheath, the sheath serves as a spacer between the lateral links.
Other advantages of the invention will appear with the following detailed description of particular embodiments of the invention, referring to the following drawing in which :

Fig. 1 is a top view of a pin according to the invention;
Fig. 2 is a top view of a locking piece;
Fig. 3 is a schematic view of a pin assembled with the locking piece in a lateral link;
Fig. 4 is a top view of a pin with only one recess;
Fig. 5 represents a top view and a side view of pin similar to the pin of Fig. 4, but with the recess consisting in two excavations;
Fig. 6 shows a top view and a side view of a pin similar to the pin of Fig. 1, but where both recesses consist in two excavations.

Fig. 1 shows a pin 2 with two recesses 5, 7, each recess being located on one of the pin's ends 8, 9, and the pin body 12. Said ends 8, 9, also comprise tapered portions 10 as well as shoulders 11.
Fig. 2 shows a locking piece 6 with a finger 4 coming into recess 5 or 7 after the pin is mounted on the links of the bracelet.
Fig. 3 shows a mounted pin 2 with its end 8 secured to a lateral link 1 in cooperation with a locking piece 6, the finger 4 being inserted into the recess 5.
Identical locking pieces fit into identical casings 13 bored into lateral link 1. Casings 13 comprise regions 14 with a restricted diameter. Regions 14 preferably present sharp edges 15 as the diameter of casings 13 increases, so as to allow a clear snapping fit of shoulder 11 against edge 15.
Reference 3 on figure 3 shows the future place of a central link, or of a plurality of central links, that are to be assembled on pin 2 before a second lateral link, symmetrical to lateral link 1, is secured on end 9 according to the invention.
The assembly operation of a row of links 1,3 of the bracelet is as follows (figure 3).
The end 8 of pin 2 is pressed against the corresponding region (14) of restricted diameter of the corresponding casing (13) on the left part of link 1.
A pressure is thus applied on tapered portion 10 of the end 8 of pin 2. As a result, end 8 shrinks thanks to the elasticity provided by recess 5, and end 8 successfully enters link 1 through region 14.
The distance between the end of body 12 and shoulder 11 corresponds to the length of region 14. As a result, shoulder 11 snaps into edge 15, confirming the fit of pin 2 into link 1.
Locking piece 6 is then inserted into casing 13 form the outside, the protruding finger 4 forbidding any future retraction of end 8 out of link 1.
Figure 4 is a top view of an embodiment of the invention in which a recess 5 is cut in only one end 8, the other end 9 of the pin being cylindrical.
Figure 5 is a top view and a side view of a still different embodiment; in this embodiment, the recess is made of two perpendicular excavations 16, 17 which are cut by cutting tools. The intersection of excavations 16, 17 allow the insertion of the finger 4 of the locking piece 6.
In figure 6, the pin is of similar construction but both its ends 8, 9 are cut in the same manner.

Claims

Link pin (2) for a flexible bracelet, said pin (2) comprising a recess (5) adapted to secure it to a link (1) of a bracelet in cooperation with a locking piece (6),
characterized in that the recess (5) is located on at least one end (8) of the pin (2).
Link pin (2), according to claim 1, characterized in that two recesses (5,7) are located on both ends (8,9) of the pin (2), said recesses (5,7) cooperating with two locking pieces (6).
Link pin (2) according to claim 1, characterized in that the end (8) of the pin (2) is split and has a tapered portion (10), said tapered portion (10) being adapted to guide the end (8) of the pin (2) into a corresponding casing (13) in the link (1) prior to the locking piece (6) being secured on the pin (2).
Link pin (2) according to claim 1, characterized in that the recess (5) is cut at the end of the pin by means of a cutting tool, and consists in an excavation limited by two parallel planes.
Link pin (5) according to claim 4, characterized in that at least one cutting tool cuts a plurality of excavations (16, 17).
Link pin (2) according to claim 2, characterized in that a body (12) of pin (2) serves as a spacer between lateral links (1).
Link pin (2) according to claim 6, characterized in that the body (12) comprises a sheath (12) that is removable.