Patent Application
20160274543
The present invention relates to a striking mechanism of a clock.
Striking mechanisms with hammers have long been known in clock movements for generating sounds in the audible range, in that they are mounted to be rotatable around an axis and on their edge have a striking edge, which strikes against a circular gong, for example, when the hammer is rotated by a pre-tensioned drive spring. The oscillation of this gong then generates a desired noise and timbre.
In order to tension the drive spring and accordingly move the striking edges of the hammers away from the gongs prior to the strike, so-called leverages are provided, which cooperate with pins arranged on the hammers, and are controlled by a striking mechanism provided, inter alia, with racks. The majority of hammers can be utilised, for example, in minute repeater striking mechanisms in order to generate different sounds.
However, to prevent the hammers from touching the gongs when in their respective rest positions and to thus allow the gongs to oscillate freely after the strike, so-called countersprings are provided, which are generally made from a harder material than the drive springs and press against the same pin in the opposite direction to the drive spring. The distance between the gong and the striking edge is then arranged by adjusting the positioning of the counterspring in such a manner that there is always a space between these two parts after the strike, and therefore any unwanted additional strikes are prevented.
A minute repeater striking mechanism that uses such an arrangement of hammers is illustrated, for example, in page 219 of the book Théorie d'horlogerie by Reymondin, Monnier, Jeanneret, Pelaratti. In conventional clocks comprising such a repeater striking mechanism, the stop of the hammer is released as follows: the pin fastened in the rotatably mounted hammer reaches an end stop at a counterspring screwed onto the plate. This counterspring at the same time has an arm provided with elastic properties and a stable non-elastic arm on the opposite side. An adjusting screw provided with a point presses against this arm. If this adjusting screw is now turned to the right, the point presses against the non-elastic arm of the counterspring and at the same time the elastic arm moves the hammer via the pin in a corresponding direction. If the adjusting screw is turned in the other direction, i.e. the point of the screw moves away from the non-elastic arm, then the counterspring stays in its position. However, to change the position of the counterspring, the fastening screw must be released, and this is only possible if the hands and dial are disassembled.
A similar structure of hammers and countersprings for a striking mechanism is described in the patent document CH 706190, according to which the counterspring is screwed from the dial side and where the adjustment of the position of the counterspring is achieved by means of an eccentric provided with a pin, which is accessible from the dial. The eccentric presses against a hard rear flank of the counterspring in order to move it around its swivel axis.
A disadvantage of these known mechanisms is that the number of parts of the striking mechanism is very high and therefore the entire assembly is particularly long. A further disadvantage is that the adjustment of the rest position of the hammers is delicate, because the fastening screw of the counterspring must be released beforehand and, on the other hand, the adjusting screw adjusting screw is only accessible from the dial side, which renders subsequent correction particularly difficult.
The object forming the basis of the present invention is to overcome these disadvantages.
Working from the preamble of claim 1, this object is achieved by the characterising features of claim 1.
In the case of the hammer according to the invention, which has an elastic stop, the conventional counterspring and the associated fastening screw can be omitted. Therefore, the number of parts of the striking mechanism is reduced and the assembly simplified in this case.
Advantageous embodiments of the invention are described in the sub-claims and in the following description.
As previously, a striking mechanism, which contains a hammer according to the invention, allows the adjustment of its rest position to be conducted by means of an eccentric. According to a particularly advantageous embodiment of the invention the eccentric has a screw head, which is accessible from the rear side of the plate. Consequently, the rest position of the hammer can be corrected more quickly and easily, since neither the hands nor the dial must be disassembled for this.
A preferred exemplary embodiment of the invention is described below with reference to the attached figures, which in detail show:
For this, the external shape of the hammer 1 is configured such that an element with elastic properties has been added. The elastic element of the hammer 1 rests against an eccentric 3, which is rotatable around its axis and disposed with friction in a bore and is accessible from the rear side of the plate. As a result of the eccentricity the distance between the hammer 1 and the gong 2 can be reduced or increased by rotating the eccentric 3.
On the one hand, the eccentric 3 is preferably arranged between the rotational axis 10 of the hammer 1 and the gong 2 in order to leave as much free space as possible on the plate for other gear trains and modules besides the striking mechanism. In this case, the aim is to keep the distance between the rotational axis 10 and the axis A-A of the eccentric as small as possible so that the swivel angles become all the greater depending on the rotation of the eccentric 3, and therefore the adjustment range becomes correspondingly broader.
On the other hand, the screw groove 31 of the eccentric 3, as shown in
According to the preferred embodiment of the invention, which is shown in
The adjustable elastic stop 4 preferably has a needle-like shape, which optimises its absorption properties. Thus, a kind of fully integrated counterspring is obtained for this and a separate part is no longer needed. The needle-shaped elastic adjustable stop 4 is preferably configured in a direction that extends from the rotational axis 10 of the hammer 1, so that the torques exerted at its point are maximised. According to the preferred embodiment of
As shown in
In order to increase the acceleration of the main piece 11 of the hammer, a kind of articulated joint G—shown in dotted lines in
However, the person skilled in the art will understand from this description that the subject of the present invention covers other variants for the elastic adjustable stop. This new feature allows both the conventional counterspring and its fastening screw to be replaced in a striking mechanism without the desired absorption function for the hammer being impaired, and thus enables its adjustment and subsequent correction of the swivelling position to be simplified. Other materials, forms and directions of expansion for this elastic adjustable stop, amongst other things, are entirely possible without departing from the framework of the invention. The mentioned preferred embodiment presented in detail thus applies only as an example and should not be deemed as a restriction for the interpretation of the claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 15159693.9 | Mar 2015 | EP | regional |
