CH719609A2 - Hammer system for striking mechanism - Google Patents

Abstract

The invention relates to a hammer system (1) for a striking mechanism comprising: - a hammer (3) pivotally mounted around a hammer axis (5) and arranged to strike a sounding member (7), said hammer ( 3) comprising a drive member (9); – a winding spring (11) arranged to drive said hammer (3) to strike said sound member (7) by cooperation with said drive member (9), said winding spring (11) being fixed to a frame element at a first attachment point; – a counter-spring (13) arranged to cooperate with said drive member (9) to keep said hammer (3) away from said sound member (7) in a rest state of the system, said counter-spring (13) being attached to a frame element at a second attachment point. According to the invention, said hammer system (1) further comprises: – a first stop (15) arranged to define a rest position of said winding spring (13) by limiting its travel; – a second stop arranged to define a rest position of said counter-spring (13) by limiting its travel; said stops being arranged such that said winding spring (11) and said counter-spring (13) define, when they are in their respective rest position, a gap in which said drive member (9) is adjusted freely.

Description

Technical area

[0001] The present invention relates to the field of watchmaking. It concerns, more particularly, a hammer system for a striking mechanism.

State of the art

[0002] In a striking mechanism, a hammer is typically arranged to strike a sound organ such as a gong, having the shape of a wire, a bell, a membrane or the like under the effect of a winding spring. In some mechanisms of this type, a hammer stop defines the end of the hammer stroke. Because of the energy it stores and the inertia, the hammer deforms when it stops on the stop, this deformation allowing it to strike the sound organ. The impact of the hammer against this stop takes a lot of energy, to the detriment of the ringing, and the interaction between the hammer and its stop can also produce an unsightly noise.

[0003] Furthermore, to prevent the hammer from striking the gong simply under the effect of the movements of the wearer of the watch, a counter-spring is generally provided to balance the force exerted by the winding spring and maintain the hammer in a rest position sufficiently far from the timbre, following the strike on the sound organ. For this purpose, the counter spring must be stronger than the winding spring, and therefore always draws a lot of energy when striking. Furthermore, adjusting the balance between the spring and the counter-spring is delicate.

[0004] Document EP2362279 provides a system which overcomes the disadvantage of energy withdrawal, by proposing an active counter-spring which only comes into action briefly after the hammer has struck the sound organ. The mechanism, for making the counter-spring active, presents a significant complexity, and also represents a bulkiness of the system.

[0005] The aim of the invention is therefore to propose a hammer system for a striking mechanism in which the aforementioned defects are at least partially overcome.

Disclosure of the invention

[0006] More precisely, the invention relates to a hammer system for a striking mechanism, as defined by claim 1. This system comprises:

[0007] - a hammer pivotally mounted around a hammer axis and arranged to strike a sound organ such as a gong, a bell, a membrane or the like;

[0008] - a winding spring arranged to drive said hammer to strike said sound member and fixed to a frame element at a first attachment point;

[0009] - a counter-spring arranged to keep said hammer away from said sound member in a rest state of the system and fixed to a frame element at a second attachment point.

[0010] Said hammer further comprises a drive member arranged to cooperate with said winding spring and said counter-spring.

[0011] According to the invention, said hammer system comprises:

[0012] - a first fixed stop, arranged to cooperate directly with said winding spring in order to define a rest position of said winding spring, by limiting its travel;

[0013] - a second fixed stop, arranged to cooperate directly with said counter-spring in order to define a rest position of said counter-spring by limiting its travel;

[0014] said stops being arranged in such a way that said winding spring and said counter-spring define, in their respective rest position, a gap in which said drive member is freely adjusted.

[0015] By these means, the stops ensure that the two springs act independently of each other, and never interact directly against each other. They can thus be dimensioned independently, to optimize, on the one hand the strike of the hammer on the drum, on the other hand the recoil of the latter after a strike, since no balance between the two needs to be managed . They can therefore be lighter and less stiff than usual. Almost all of the kinetic energy of the hammer is thus transmitted to the gong, only the energy of the stroke corresponding to the return of the hammer is not converted into sound. This return energy is relatively low, given that the return spring is sized just to overcome the weight of the hammer as it returns to its equilibrium position.

Advantageously, said drive member extends parallel to said hammer axis.

Advantageously, each of said stops is part of a single stop piece fixed to a frame element, which is simple and facilitates adjustment of the system.

[0018] Advantageously, said springs are arranged in such a way that the geometric axis of said hammer is located within an obtuse angle defined by the extension of said winding spring and said counter-spring, said axis being located in particular on the side of said attachment points.

[0019] Advantageously, said springs are arranged in such a way that said gap is defined by an acute angle made between the extension of said winding spring and said counter-spring, said gap being found in particular on the side remote from said second point of attached.

The hammer system defined above is intended to be integrated into a ringing mechanism, such as a repeating ringer, an alarm clock, a ringing countdown or the like, which is in turn intended to take place in a timepiece.

Brief description of the drawings

[0021] Other details of the invention will appear more clearly on reading the description which follows, made with reference to the appended drawings in which: – Figure 1 is an isometric view of a hammer system according to one embodiment of the invention, in its resting state; – Figure 2 is a bottom view of the hammer system of Figure 1 in its rest state; – Figure 3 is a bottom view of the hammer system of Figure 1, the hammer having been raised; and – Figure 4 is a bottom view of the hammer system of Figure 1, the hammer being in contact with the sound member.

Mode of carrying out the invention

Figures 1 and 2 illustrate a non-limiting embodiment of a hammer system 1 according to the invention, in its rest state. This hammer system 1 is intended to be part of a ringing mechanism which can be of any kind, such as a snooze, an alarm clock, a ringing countdown or the like, which can be integrated into a room watchmaking.

The system 1 comprises a hammer 3 pivotally mounted around a hammer axis 5, which comprises a shaft defining a geometric axis of rotation. The hammer 3 is, of course, arranged to strike a sound organ 7, illustrated here in the form of a stamp, but bells, membranes and even studs fixed to the bottom of a timepiece are also possible.

The hammer 3 further comprises a drive member 9 arranged to cooperate with a winding spring 11 mounted on a frame element (not illustrated) at a first attachment point 12 which is fixed relative to the frame , the winding spring 11 being arranged to exert a force tending to push the hammer 3 towards the sound member 7 in order to strike it. A counter-spring 13 is also provided, also mounted on a frame element (not illustrated) at a second attachment point 14 which is also fixed relative to the frame, the counter-spring 12 being arranged to push the member drive 9 towards the winding spring 11 in order to keep the hammer 3 away from the sound member 7 in the rest state. In the illustrated embodiment, the drive member extends parallel to the hammer axis 5, and is a hammer tigeron, but it can also be a stud or the like. Alternatively, two or even more drive members 9 can be provided, one cooperating with the winding spring 11, the other with the counter-spring 13.

According to the invention, the system 1 comprises a first stop 15 arranged to define the rest position of the winding spring 11, by providing a surface against which the latter rests in the rest state of the system 1 For the remainder, a second stop 17 is provided, defined by a surface against which the counter-spring 13 also rests to define its rest position.

[0026] In the illustrated embodiment, the stops 15, 17 are part of the same stop part 19 fixed to a frame element, but it is possible to provide several elements which carry the stops 15, 17.

[0027] In the rest state of system 1, the springs 11, 13 define a gap in which the drive member 9 is freely adjusted, that is to say without constraining either one or the the other of the springs 11, 13. The positioning of the drive member 9 in this gap by the springs 11, 13 therefore defines the position of the hammer 3 at rest. In a limiting case, contact between the drive member 9 and each of the springs 11, 13 is of course admitted, provided that they each remain in contact with their respective stops 15, 17 when the hammer 3 is at rest and is not subject to force from lifting, impact or other external acceleration.

Consequently, each of the springs 11, 13 acts independently of the other, and their elastic properties (stiffness, length, thickness, height) can be determined individually because there is no longer any need to manage a balance between the springs. two.

[0029] Each spring 11, 13 can thus be lighter and less stiff than in a typical case of the prior art, without requiring a complex system as described in document EP2362279.

[0030] At the geometric level, the extension of the winding spring 11 crosses the counter-spring 13 such that the (geometric) axis of rotation 5 of the hammer 3 is located inside the obtuse angle thus defined , in particular on the side of the attachment points 12, 14. Furthermore, the stops 15, 17 are located inside the acute angle thus defined, on the side remote from the second attachment point 14.

[0031] Figures 3 and 4 illustrate more clearly the complete independence of the springs 11, 13.

[0032] Figure 3 illustrates the winding phase in which the hammer 3 was actuated by a lift (not shown), thus lifting and constraining the winding spring to strike the sound member 7, according to the arrow shown. The counter-spring 13 remains in contact with the second stop 17 and is therefore not involved at this moment.

[0033] Figure 4 illustrates the situation at the time of impact of the hammer 3 on the sound member 7. The winding spring 11 is in contact with the first stop 15 and is therefore no longer involved. The counter-spring 13 having been lifted from the second stop, it is forced to then return the hammer 3 to its rest position, according to the arrow shown. The mechanism then finds itself in the position illustrated in Figure 2.

In view of the above, it is clear that at most, only one of the springs 11, 13 acts on the drive member 9 at a given moment, and that the two springs 11, 13 do not never interact with each other. They can thus be dimensioned independently of each other in order to obtain the desired striking force, respectively the recoil force. In addition, the counter-spring can be sized slightly, in order to take a minimum of energy from the hammer and thus conserve the energy stored to strike the gong. There are also no shocks that could cause unsightly noises.

[0035] Although the invention has been previously described in connection with specific embodiments, other additional variants are also possible without departing from the scope of the invention as defined by the claims.

Claims (7)

1. Hammer system (1) for striking mechanism comprising: – a hammer (3) pivotally mounted around a hammer axis (5) and arranged to strike a sound member (7), said hammer (3) comprising a drive member (9); – a winding spring (11) arranged to drive said hammer (3) to strike said sound member (7) by cooperation with said drive member (9), said winding spring (11) being fixed to a frame element at a first attachment point (12); – a counter-spring (13) arranged to cooperate with said drive member (9) to keep said hammer (3) away from said sound member (7) in a rest state of the system, said counter-spring (13) being attached to a frame element at a second attachment point (14); characterized in that said hammer system (1) further comprises: – a first fixed stop (15), arranged to cooperate directly with said winding spring (13) in order to define a rest position of said winding spring (13); – a second fixed stop (17), arranged to cooperate directly with said counter-spring (13) in order to define a rest position of said counter-spring (13); said stops (15, 17) being arranged in such a way that said winding spring (11) and said counter-spring (13) define, when they are in their respective rest position, a gap in which said protection member drive (9) is freely adjusted. 2. Hammer system (1) according to the preceding claim, wherein said drive member (9) extends parallel to said hammer axis (5). 3. Hammer system (1) according to one of the preceding claims, wherein each of said stops (15, 17) is part of a single stop piece (19) fixed to a frame element. 4. Hammer system (1) according to one of the preceding claims, wherein said springs (11, 13) are arranged such that the geometric axis (5) of said hammer (3) is inside an obtuse angle defined by the extension of said winding spring (11) and said counter-spring (13). 5. Hammer system (1) according to one of the preceding claims, wherein said springs (11, 13) are arranged such that said gap is defined by an acute angle made between the extension of said winding spring (13). ) and said counter-spring (11). 6. Ringing mechanism comprising a hammer system (1) according to one of the preceding claims. 7. Timepiece comprising a striking mechanism according to the preceding claim.