Pushpin for a watch strap
Patent Information
- Application Number
- EP2023742431
- Authority / Receiving Office
- EP · EP
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2022-07-04
- Filing Date
- 2023-06-29
- Publication Date
- 2025-05-14
- Estimated Expiration
- 2043-06-29
AI Technical Summary
Existing spring bars for watch straps require a special tool for detachment, making it difficult for users to change straps easily and without damaging the bracelet, and the introduction of a radial index complicates removal and insertion processes.
A spring bar design featuring a button and elastic clip index finger that can be reversibly fixed on the piston, allowing for detachment without breaking the bracelet and enabling easy insertion and removal without tools.
Enables users to change watch straps independently without damaging the bracelet and facilitates easy installation of new straps by allowing the index finger to be detached and reattached as needed, improving user convenience and flexibility.
Smart Images
Figure 1.1
Abstract
Description
[0001] Spring bar for watch strap
[0002] The present invention relates to a spring bar comprising a hollow rod, a spring and a piston housed inside the hollow rod, and a first and a second pivot arranged at the two ends of the latter, the first pivot being integral with the rod in a coaxial position, and the second pivot being fixed in a coaxial position on the end of the piston furthest from the first pivot, the piston being arranged to slide concentrically with the rod, between a first position, called the extended position of the second pivot, and a second position, called the retracted position of the second pivot, and the spring being arranged so as to return the piston towards the extended position of the second pivot.
[0003] PREVIOUS ART
[0004] It is known to use two spring bars conforming to the above definition to connect the strands of a flexible bracelet to the two pairs of horns of a watch case. Each bar can for example be inserted into a loop of the bracelet with its two pivots protruding on either side, the latter then being housed in two blind bores arranged opposite each other in the two horns of one of the pairs of horns.
[0005] To detach one of the strap strands from the watch case, the first step is to slide the spring bar's piston inside the stem against the spring's return force, so as to bring the second pivot into the retracted position. This operation is normally carried out using a special tool. However, the need for a special tool has been found to deter most people from changing their watch straps themselves. Until recently, it was not common practice to change a watch strap unless it was visibly worn or damaged. Since strap changes were infrequent, this job could be entrusted to a watchmaker, so the need for a special tool was not seen as a problem.
[0006] The situation is a little different today. For a number of years now, manufacturers have been offering assortments of straps for the same watch. As a result, there are now many more opportunities to change straps (for example, to adapt the style of the watch to a particular activity or to the owner's clothing). The need quickly arose to allow the wearer of a watch to change the strap themselves, and to do so easily and without the need for tools.
[0007] A known solution for satisfying this need is to use spring bars equipped with a radial index. This index is rigidly fixed to the piston by one of its ends, and it is arranged to extend radially through a first longitudinal slot made in the stem of the bar, as well as through a second longitudinal slot made in the loop, so that the free end of the radial index protrudes beyond the surface of the bracelet. It will be understood that the presence of the radial index allows the wearer of the watch to slide the piston inside the bar simply by using his thumb, without having to use a tool. This known solution is not entirely without drawbacks. Indeed, the presence of the radial index prevents the bar from being removed from the loop in which it is inserted without unstitching or cutting the bracelet strand.In addition, a spring bar that is equipped with a radial index must necessarily be inserted into the bracelet strand intended for it during manufacture. The presence of the index prevents it from being inserted into the loop of the finished strand.
[0008] BRIEF STATEMENT OF THE INVENTION
[0009] An object of the present invention is to overcome the disadvantages of the prior art which have just been explained. The present invention achieves this and other objects by providing a spring bar for a watch strap according to the appended claim 1.
[0010] According to the invention, the index finger comprises a button and an elastic clip on which the button is mounted. The elastic clip is adapted to be reversibly attached to the piston. It will be understood that an advantage of the invention is that it is possible to detach the index finger from the rest of the bar without breakage, by simply unclipping the clip from the piston. Thanks to this feature, a spring bar according to the invention can be removed from the loop in which it is inserted without this requiring the integrity of the bracelet strand to be affected. It is furthermore possible to insert the bar, without its index finger, into the loop of a new ready-to-use bracelet, and then to replace the index finger by inserting the elastic clip into the longitudinal slot of the hollow rod and clipping it onto the piston.
[0011] BRIEF DESCRIPTION OF THE FIGURES
[0012] Other characteristics and advantages of the present invention will appear on reading the description which follows, given solely by way of non-limiting example, and made with reference to the appended drawings in which: Figures 1A and 1B are two partial perspective views showing respectively one of the two pairs of horns of a watch case, and the end of a bracelet strand comprising a loop serving as a housing for a spring bar according to a particular embodiment of the invention; Figure 2 is an exploded perspective view showing the various constituent elements of the spring bar of Figure 1B; Figure 3 is a longitudinal sectional view of the spring bar of Figures 1B and 2; Figure 4A illustrates the elastic clamp of the spring bar of Figures 1B, 2 and 3 before it is clipped onto the reduced diameter portion of the piston;Figure 4C illustrates the same elastic clamp clipped onto the reduced diameter portion of the piston; finally, Figure 4B illustrates how the jaws of the elastic clamp can elastically spread apart to allow the elastic clamp to be clipped and unclipped.;
[0013] DETAILED DESCRIPTION OF AN EMBODIMENT
[0014] In the present patent application, the meaning given to the verb “clip” is: to fix with an elastic clip or a spring clip.
[0015] The watch case (referenced 1) which is the subject of the partial view in figure 1A is of the classic type. It has in particular two pairs of horns, only one of which (referenced 3) is visible in the figure.
[0016] Figure 1B is a partial perspective view showing the proximal end of one of the strands 5 of a watch strap. The strand 5 is preferably made of a flexible material such as leather for example. The proximal end of the strand 5 is folded into a loop and glued or sewn, so as to form a loop 7 oriented perpendicular to the longitudinal axis of the strand 5. This loop is adapted to receive a spring bar 9.
[0017] Figures 2 and 3 are two views, respectively in exploded perspective and in longitudinal section, of a spring bar 9 according to an exemplary embodiment. The bar firstly comprises a hollow rod 11, a spring 17 and a piston 19 which are housed inside the hollow rod, and a first and a second pivot 13, 15 which are arranged at the two ends of the rod. The first pivot 13 is integral with the rod 11 in a coaxial position. It is arranged in the axis of the hollow rod so as to protrude from the end of the latter. By way of example, the first pivot 13 may comprise a base which is crimped inside the opening at the end of the hollow rod 11, as illustrated in Figure 3. According to alternative variants, the base of the pivot 13 could for example be welded or glued inside the opening of the rod 11.The second pivot 15, for its part, is fixed in a coaxial position on the end of the piston 19 which is furthest from the first pivot 13. It will be understood that the piston 19 is arranged to slide longitudinally inside the rod 11, in one direction or the other between a first position, called the extended position of the second pivot 15 (which is illustrated in FIG. 3), and a second position (not shown) which is called the retracted position of the second pivot 15. It can also be seen that the spring 17 is arranged inside the rod so as to be compressed between the piston.
[0018] 19 and the base of the first pivot 13. It will be understood that the return force exerted by the spring 17 on the piston 19 tends to push the latter towards the extended position of the second pivot 15.
[0019] The spring bar also comprises an index 21 which is intended to be fixed on the piston 19 (see figure 3) and to protrude radially outside the hollow rod 11 by a longitudinal slot whose ends are referenced 23a and 23b in figure 3. In the present example, it is the distance separating the two ends 23a and 23b of the longitudinal slot which determines the length of the stroke which the piston 19 is free to perform inside the hollow rod 11. Indeed, in one direction, the index 21 abuts against the end 23a when the piston 19 reaches the extended position of the second pivot, and in the other direction, the index 21 abuts against the end 23b when the piston 19 reaches the retracted position of the second pivot. In the embodiment which is the subject of the present example. The index 21 is formed by a button, or slider, 25 is a clamp comprising two elastic jaws 27a and 27b. The button 25 is rigidly mounted on the elastic clamp.The latter allows the reversible fixing, or clipping, of the button 25 on the piston 19 by elastic fitting.
[0020] Referring to both Figures 2 and 3, as well as Figures 4A, 4B and 4C, it can be seen that the piston 19 has a portion of reduced diameter (referenced 20) which is delimited on either side by two shoulders (referenced 29a and 29b). As shown in the figures, the jaws 27a, 27b and the portion of reduced diameter of the piston 19 are adapted to fit together elastically. This fit results from the fact that the portion of reduced diameter
[0021] 20 can be inserted between the jaws 27a, 27b of the elastic clamp, the latter simultaneously being inserted both between the two shoulders 29a, 29b. Preferably, the distance between the two shoulders 29a, 29b should be only very slightly greater than the width of the jaws 27a, 27b, so as to minimize the distance over which the jaws have the possibility of ripping. It will be understood in fact that the shoulders 29a, 29b fulfill a stop function, defining a gap outside of which the jaws 27a, 27b cannot come out when the index 21 is clipped onto the reduced diameter portion 20 of the piston.Thanks to this characteristic, the attachment of the index 21 to the piston 19 is almost rigid, which allows the wearer of the watch to slide the piston inside the hollow rod 11 by simply pushing the free end of the index 21 a corresponding distance towards the end of the bar 9 occupied by the first pivot 13.
[0022] Figures 4A, 4B and 4C are three snapshots showing different stages of clipping (or unclipping) the index 21 onto the (or the) piston 19. More specifically, Figure 4A shows the index 21 before it is clipped onto the portion 20 of the piston 19 which has a reduced diameter. Figure 4C shows the index 21 once clipped onto the piston. Finally, Figure 4B illustrates how the jaws 27a, 27b of the elastic clamp can elastically spread apart to allow clipping or unclipping.
[0023] Still referring to the same figures, it can be seen that the distal part of each of the jaws 27a, 27b comprises a transverse recess (referenced respectively 31a and 31b) which gives the profile of the jaw a hook shape. It can also be seen that the transverse recesses 31a and 31b extend opposite one another. In the example illustrated, the recesses 31a and 31b have rounded bottoms whose radius of curvature is substantially equal to the radius of the reduced diameter portion of the piston 19. In addition, as shown in Figures 4A and 4C, as long as no mechanical stress causes the elastic jaws 27a and 27b to move apart, the distance separating the bottom of the recess 31a from the bottom of the recess 31b is substantially equal to the diameter of the reduced diameter portion 20.As shown in Figure 4C, this arrangement has the advantage of allowing the jaws 27a, 27b to trap and immobilize the reduced diameter portion 20 with a minimum of play, without the presence of the reduced diameter portion 20 forcing the jaws 27a, 27b to remain permanently under stress.
[0024] Referring again to Figure 1B, it can be understood that the part of the strand 5 which is folded into a loop to form the loop 7 is also pierced with an elongated opening which is arranged parallel to the longitudinal axis of the loop (the elongated opening in the loop 7 is hereinafter referred to as the “second longitudinal slot”, so as to distinguish it from the longitudinal slot which the bar has, the latter being, for its part, hereinafter referred to as the “first longitudinal slot”). When the spring bar 9 is installed in the loop 7 it must be turned so that the first and second longitudinal slots are superimposed, so as to allow the free end of the index finger 21 to protrude beyond the surface of the bracelet (as illustrated in Figure 1B) while its other end is fixed on the piston 19.
[0025] An implementation of the invention will now be described in a particular context by way of example only; this description is an opportunity to highlight certain advantages of the invention. First of all, for aesthetic reasons, when a bracelet is intended to equip a high-end watch, the bars that serve to connect the strands of the bracelet to the lugs of the watch case are often made of the same material as the watch case. In particular, when it is a precious metal watch, the bars are most often also made of precious metal. It will be understood that precious metal bars are themselves precious objects. Under these conditions, it would be difficult to conceive of throwing away the bars when the bracelet they equip needs to be replaced.
[0026] When purchasing a high-end watch, an assortment of straps is often given to the buyer with the watch. The various straps in the assortment are usually pre-equipped with spring bars; these are matched to the watch case. When the owner of the watch wishes to change the strap, he can remove it himself by using the button 25 to retract the second pivot 15. Once the pivot is retracted, the spring bar can be tilted so as to allow the strap to be detached by releasing the spring bar from the lug spacer. Then, once the old strap is removed, the owner of the watch can install the new strap. To do this, he first inserts the first pivot 13 (the fixed pivot) of the spring bar of one of the strands of the new strap into the blind bore of a first lug.Then, he actuates the button 25 to retract the second pivot 15, so as to position the other end of the bar opposite the bore of the second horn. Once the bar is correctly positioned between the two horns, he releases the button 25 to allow the spring 17 to return the piston 19 to the extended position of the second pivot 15. It will be understood that in the extended position, the second pivot 15 is engaged in the bore of the second horn, so that the bracelet strand is attached to the watch case.
[0027] The owner also has the option of wearing his watch with a new strap that is not part of the assortment received with the watch (it could be, for example, the strap of another watch whose case is not made of the same material). In this case, the owner must go to the watchmaker with his watch and the new strap. The watchmaker detaches the old strap from the watch, and unclips the index from each of the bars, so that the bars can then be removed from the loops of the first strap. The two recovered bars are then inserted into the loops of the new strap. During this step, the watchmaker must take care that the two bars are turned so that the longitudinal slot opened in the loop of each of the two strands of the strap is properly superimposed on the longitudinal slot presented by the bar that is inserted into this loop.Using a magnifying glass, the watchmaker can then insert the indexes, clips forward, into the openings, and clip them onto the pistons.
[0028] It will further be understood that various modifications and / or improvements obvious to a person skilled in the art may be made to the embodiments which are the subject of the present description without departing from the scope of the present invention defined by the appended claims.
Claims
CLAIMS Spring bar (9) for watch strap comprising a hollow rod (11), a first and a second pivot (13, 15) arranged respectively at the two ends of the rod, as well as a spring (17) and a piston (19) housed inside the rod (11), the first pivot (13) being integral with the rod in a coaxial position, and the second pivot (15) being fixed in a coaxial position on the end of the piston (19) furthest from the first pivot (13), the piston (19) being arranged to slide concentrically with the rod (11), between a first position, called the extended position of the second pivot (15), and a second position, called the retracted position of the second pivot (15), and the spring (17) being arranged so as to return the piston (19) towards the extended position of the second pivot, the spring bar (9) further comprising an index (21) mounted radially on the piston (19) and protruding from the rod (11) by a longitudinal slot,the index (21) being manually operable to slide the piston (19) against the return force of the spring (17), so as to bring the second pivot (15) into the retracted position; characterized in that the index (21) comprises a button (25) and an elastic clip (27a, 27b) on which the button is mounted, the elastic clip being adapted to be fixed reversibly on the piston (19). Spring bar (9) for watch strap according to claim 1, characterized in that the elastic clip (27a, 27b) is in one piece. Spring bar (9) for watch strap according to claim 1 or 2, characterized in that the piston (19) has a portion of reduced diameter (20), and in that the elastic clip comprises two jaws (27a, 27b) which are separated by a distance slightly less than the diameter, of the reduced diameter portion (20) when the jaws are not constrained, the two jaws (27a, 27b) being further capable of flexing elastically to allow the reduced diameter portion (20) to be inserted between the two jaws, the latter comprising two transverse hollows (31a, 31b) extending opposite one another and between which the reduced diameter portion (20) can be housed by elastic fitting. Spring bar (9) for watch strap according to claim 3, characterized in that the portion of reduced diameter (20) is delimited on either side by two shoulders (29a, 29b) facing each other, the two jaws (27a, 27b) being provided to be inserted between the two shoulders when the portion of reduced diameter (20) of the piston (19) is inserted between the jaws (27a, 27b).