FIG. 5 is a partial view of FIG. 1 with the two parts of the positioning device disengaged;
FIG. 6 is a view similar to FIG. 5 showing the band connecting member at the other end of the adjustment device;
FIG. 7 is a partial view in longitudinal section similar to FIG. 5 with the two parts of the positioning device engaged, of the second embodiment of the clasp of the invention;
FIG. 8 is a view similar to FIG. 7 with the two parts of the positioning device disengaged;
FIG. 9 is a perspective view of FIG. 8 without the front part 13′b of the cover to improve visibility;
FIG. 10 is a view similar to FIG. 7, showing a variant of the second embodiment;
FIG. 11 is a view similar to FIG. 10 with the two parts of the positioning device disengaged;
FIG. 12 is a perspective view of FIG. 11 without the front part 13″b of the cover to improve visibility.
The clasp illustrated in FIGS. 1 and 2 is a known type of clasp described in EP 1 654 950: it has two arms 1, 2 extending in the longitudinal direction of the clasp and hinged at one of their ends about a hinge pin 3. The free end of the arm 1 has a hook element 4 which takes the form of a transverse element parallel to the hinge pin 3. This hook element 4 is situated in a part la of the free end of the arm 1 which is outwardly curved. A space is provided between this hook element 4 and the bottom of this curved part 1a to allow a hook member to be inserted between the hook element 4 and the bottom of the curved part 1a, as will be explained later. This same free end is also connected to two hinge pins 5, 6 parallel to the hinge pin 3 of the arms 1, 2. One 5 of these hinge pins serves as the pivot for a locking cover 7, while the other serves as the pivot for one end of one of the halves of the band (not shown).
An assembly member 9 is hinged to the free end of the long arm 2 about the hinge pin 8 and has two other hinge pins 10 and 11. The hinge pin 10 serves as the pivot for a locking lever 12 and the hinge pin 11 serves to connect a cover 13 extending in the longitudinal direction of the clasp.
The assembly member 9 has a surface 9a adjacent to the inside face of the upper wall of the cover 13. This surface 9a is to prevent the cover 13 pivoting about the hinge pin 11. The end of this cover 13 nearest the free end of the arm 2 covers the rear end of the locking lever 12.
As can be seen in FIG. 2 in particular, one end of a spring 15 bears on a rod 16 connected to the assembly member 9 and passes around the pin 10 which hinges this assembly member 9 to the locking lever 12. The other end of this spring 15 bears against the inside face of the upper wall of the locking lever 12. As a result, this spring creates a torque on the locking lever 12 that tends to turn it in the counterclockwise direction when viewing FIGS. 1 and 2. A second spring identical to the spring 15 (not visible) passes around the hinge pin 10.
On the locking lever 12 is a locking hook 17 shaped so as to be able to engage between the locking element 4 attached to the free end of the arm 1 and the bottom of the curved part la of this arm 1, in which position it is held by the torque applied to it by the spring 15. Lifting the front part of the lever 12 so that it pivots clockwise, against the torque of the spring 15 opens the clasp.
It should be understood that the closing mechanism of the clasp is not part of the invention and can be replaced with any other appropriate mechanism.
In cross section, the cover 13 forms an inverted U, as illustrated in FIG. 3. The inside face of the bottom of the U of this cover has positioning teeth 14, similar to the teeth of a rack. The inside faces of the two side walls of this cover 13 each comprise a guide track 18 formed, in this example, by milling into the thickness of these side walls. Two sliding rollers 19 whose diameters both correspond to the width of one guide track 18 pivot on the respective ends of two spring bars 21, 22 which exert antagonistic lateral forces on the opposite rollers which elastically keep them in the guide tracks 18. The spring bars 21, 22 are housed in transverse passages running through a connecting member 20. This connecting member 20 is used to connect one end of the band as explained later. Owing to the complementary profiles of the rollers 19 and of the tracks 18 and owing to the antagonistic forces acting on the rollers 19 to keep them in the tracks 18, when the two pairs of sliding rollers 19 of the connecting member 20 are engaged in the opposite guide tracks 18, each pair of sliding rollers 19 has one degree of freedom defined by the longitudinal path of the tracks 18, the connecting member 20 connected to the two pairs of rollers 19 can therefore move only translationally, with friction only between the rollers 19 and the guide tracks 18.
As can be seen in FIGS. 1, 3 and 4 in particular, an immobilizing element 24 pivots on the bar 21. This immobilizing element 24 has a tooth 24a shaped to engage between the teeth 14 on the bottom of the U of the cover 13 when the immobilizing element 24 is in the position around the bar 22 illustrated in FIGS. 1-4. The immobilizing element 24 is kept with the tooth 24a in this position of engagement in the teeth 14 of the rack by a nose 24b designed to catch elastically (by the bending of the bars 21, 22) on the bar 22, as shown in FIG. 4.
As illustrated in FIGS. 4 and 5, the immobilizing element 24 also serves to take two side links 25a, 25b for attaching to one end of the band (not shown) using a screw 26. These two side links 25a, 25b are fixed by press fitting the respective ends of a rod 27 (FIGS. 1 and 2) into two blind holes in these side links 25a, 25b.
To disengage the tooth 24a of the immobilizing element 24 from the teeth 14 of the rack, the user simply pivots the side links 25a, 25b about the rod 27 to a position forming an angle with the cover 13 and pulls the band—which is extremely easy when the band is attached to the screw 26.
As soon as the tooth 24a is disengaged from the teeth 14 of the rack, the movable assembly formed by the connecting member 20, the parallel spring bars 21, 22, the rollers 19 and the immobilizing element 24 can be slid freely like a carriage along the guide tracks 18. The distance it can travel is limited by the ends of the milled tracks 18. The length of the rack formed by the teeth 14 is approximately equal to the length of the tracks 18. As soon as the movable assembly has reached its new position of adjustment, the user simply pivots the immobilizing element 24 in the opposite direction to snap the nose 24b back over the bar 22.
A retention element formed by a small projection 24c is advantageously arranged on one of the faces of the immobilizing element 24 in such a way as to come against the inner edge of the connecting member when the immobilizing element 24 is pivoted out of engagement with the tooth 24a, as shown in FIG. 5. This retention element keeps the immobilizing element in its pivoted position shown in FIG. 5 as the connecting member is slid along the tracks 18 with which the rollers 19 are in engagement so that the tooth 24a cannot interfere with the rack teeth 14.
As can be seen, the band can only be adjusted intentionally and in no case accidentally or by inadvertence, because it can only be adjusted after the clasp has been opened, and the nose 24b then has to be disengaged from the bar 22 on which it is elastically held.
The second embodiment, illustrated in FIGS. 7, 8 and 9, differs from the first only in that the tooth 20′a is not now integral with an immobilizing element pivoting on the bar 21, the immobilizing element 20′a being stationary, and the bar 21 extends through it. To engage and disengage the immobilizing tooth 20′a relative to the teeth 14′ of the rack, the rack is on a flap 13′a independent of the bottom of the U of the cover 13′ which is formed by two parallel parts, a front part 13′b and a rear part 13′c separated from one another by the breadth of the flap 13′a and joined by hinge pins, including a transverse hinge pin 28 on which one end of the flap 13′a pivots.
The other end of the flap 13′a is hinged about a transverse hinge pin 40 to a control lever 29 which has one end pivoting on the cover 13, about a transverse hinge pin 30. The other end 29a of this control lever 29 projects, when the adjacent end of the cover 13′ is down (FIG. 7), to provide a means of lifting it when the user wishes to disengage the teeth 14′ of its rack from the fixed tooth 20′a in order to allow the movable assembly 20′, 21 to be slid along the guide tracks 18. Afterwards, the user simply pushes the flap 13′a back down to engage the fixed tooth 20′a with one of the teeth 14′ of the rack integral with the flap 13′a.
The flap 13′a and the control lever 29 form a toggle joint, so that when the flap 13′a is moved away from its position shown in FIG. 8 to the shut position shown in FIG. 7 it comes under tension, while the control lever 29 comes under compression because of the different path of the hinge pin 40 pivoting simultaneously about the hinge pin 28 and about the hinge pin 30. As a result, depending on whether the hinge pin 40 is on one side or the other side of the line L connecting the transverse hinge pin 28 to the hinge pin 30, the stresses acting on the flap 13′a and on the control lever 29 exert two torques of opposite directions which keep the flap 13′a open, or closed, respectively, as illustrated in FIGS. 8 and 7, respectively, thus forming a bistable system on the two sides of the line L.
The advantage of this embodiment is that it allows the length of the band to be adjusted without removing the watch from the wrist. It may also be pointed out that in the shut position, the end 29a of the control lever 29 which projects from the end of the cover 13′ is covered by the locking cover 7 illustrated in FIGS. 1 and 2. There is therefore no risk that the control lever 29 will be operated accidentally.
In the variant shown in FIGS. 10-12, the control lever 29 is replaced with a toggle joint comprising two arms 31, 32 articulated together at one end of each about a hinge pin 33. Arm 31 is actually two arms. The second end of the arm 32 pivots about a transverse spindle 34 connected to the two halves 13″b, 13″c of the cover 13″. A prestressed helical spring 35 is mounted on the transverse spindle 34 and applies a counterclockwise torque to the arm 32. The second end of the double arm 31 is shaped into a stop 31a designed to bear against the lower face of the flap 13″a. This second end of the arm 31 pivots on the free end of the flap 13a via a transverse hinge pin 37.
As can be seen by comparing the respective positions of the arms 31, 32 in FIGS. 10-12, as the hinge pin 37 moves from the flap-out position (FIG. 11) to its shut position (FIG. 10), this hinge pin 37 passes through a point of equilibrium relative to the hinge pin 33 of the toggle joint, so that the counterclockwise torque of the spring 35 on the arm 32 keeps the flap 13″a open once the hinge pin 37 has passed the position of equilibrium relative to the hinge pin 33, while this same torque closes the flap 13″a and keeps it closed once the hinge pin 37 has passed this position of equilibrium in the opposite direction. In view of the rigidity of the arms 31, 32 of the toggle joint, the system is able to pass through the position of equilibrium because of the helical spring 35 mounted on the transverse hinge pin 34. Keeping the flap 13″a open also allows the movable assembly 20′ to slide freely in either direction all the way along the tracks 18.
As will also be seen, in this second embodiment, the rollers 19 are replaced with sliding shoes 39, 39′ engaged in guide tracks 18 formed in the inside faces of the two side walls of the cover 13′, 13″. The sliding shoes 39, 39, are made of a friction-reducing material that is also wear-resistant. They have a slightly arched profile which permits a precise fit in the respective guide tracks 18. These shoes may be either in one piece made of a material with a low coefficient of friction, such as a plastic, or formed essentially from metal covered with a wear-resistant material with a low coefficient of friction.
Naturally, it is perfectly possible to replace the rollers 19 of the first embodiment with the sliding shoes 39, 39′ and vice versa. The forces of friction on the sliding shoes 39, 39′ can be adjusted through the lateral forces applied to these sliding shoes 39, 39′ by the spring bar 21.
Patent Application
20080083101
