Barrel with substantially constant torque

Abstract

A barrel for a timepiece. The barrel has a device for limiting the number of running rotations of the barrel, wherein this device still allows any number of winding rotations of the barrel.

Claims

1. A barrel for a timepiece, wherein said barrel comprises: a device to limit a number of running rotations of the barrel, wherein said device still allows any number of winding rotations of the barrel, and an outer periphery of said device in a radial direction of the barrel is disposed radially inward with respect to an outer periphery of a mainspring of the barrel in the radial direction.

2. The barrel according to claim 1, wherein said device is made up of a first device to release the winding rotations and a second device to limit the number of running rotations of the barrel, wherein said first device works in a first placement plane and said second device works in a second, different placement plane.

3. The barrel according to claim 1, wherein said device comprises a rotatable positioning ring mounted on the barrel.

4. The barrel according to claim 3, wherein device further comprises an indexing mechanism to rotatably position said rotatably mounted positioning ring.

5. The barrel according to claim 4, wherein said indexing mechanism comprises a detent spring that lies between engaging teeth of a gearwheel, wherein said gearwheel is driven by a placement finger non-rotatably fixed to a spring shaft and meshes with an inner toothing of the positioning ring.

6. The barrel according to claim 3, wherein said rotatable positioning ring is fitted in a stack between a base of the barrel and a cover plate.

7. The barrel according to claim 3, wherein said positioning ring comprises inner toothing, which meshes with a gearwheel, wherein said gearwheel is driven by a placement finger non-rotatably fixed to a spring shaft and wherein said positioning ring presents a gap between a first locating surface and a second locating surface on its outer edge.

8. The barrel according to claim 3, wherein said positioning ring comprises a first pin, which interacts with a return spring in a placement plane in a winding direction when winding up the barrel.

9. The barrel according to claim 8, wherein said pin is located in a same angular section as a gap between a first locating surface and a second locating surface.

10. The barrel according to claim 8, wherein said return spring is U-shaped and is attached to the barrel with the aid of a shoulder pin.

11. The barrel according to claim 7, wherein said first locating surface of said positioning ring interacts with a second pin located on the barrel in a second placement plane in order block a motion of the barrel according to a predetermined number of running rotations in a running direction.

12. A barrel for a timepiece, wherein said barrel comprises: a device to limit a number of running rotations of the barrel, wherein said device still allows any number of winding rotations of the barrel, said device comprises a rotatable positioning ring mounted on the barrel, and said rotatable positioning ring is fitted in a stack between a base of the barrel and a cover plate.

13. The barrel according to claim 12, wherein said device is made up of a first device to release the winding rotations and a second device to limit the number of running rotations of the barrel, wherein said first device works in a first placement plane and said second device works in a second, different placement plane.

14. The barrel according to claim 12, wherein device further comprises an indexing mechanism to rotatably position said rotatably mounted positioning ring.

15. The barrel according to claim 12, wherein said positioning ring comprises inner toothing, which meshes with a gearwheel, wherein said gearwheel is driven by a placement finger non-rotatably fixed to a spring shaft and wherein said positioning ring presents a gap between a first locating surface and a second locating surface on its outer edge.

16. The barrel according to claim 12, wherein said positioning ring comprises a first pin, which interacts with a return spring in a placement plane in a winding direction when winding up the barrel.

17. A barrel for a timepiece, wherein said barrel comprises: a device to limit a number of running rotations of the barrel, wherein said device still allows any number of winding rotations of the barrel, said device comprises a rotatable positioning ring mounted on the barrel, and said positioning ring comprises a first pin, which interacts with a return spring in a placement plane in a winding direction when winding up the barrel.

18. The barrel according to claim 17, wherein said device is made up of a first device to release the winding rotations and a second device to limit the number of running rotations of the barrel, wherein said first device works in a first placement plane and said second device works in a second, different placement plane.

19. The barrel according to claim 17, wherein device further comprises an indexing mechanism to rotatably position said rotatably mounted positioning ring.

20. The barrel according to claim 17, wherein said positioning ring comprises inner toothing, which meshes with a gearwheel, wherein said gearwheel is driven by a placement finger non-rotatably fixed to a spring shaft and wherein said positioning ring presents a gap between a first locating surface and a second locating surface on its outer edge.

Description

(1) The individual figures show in detail:

(2) FIGS. 1A and 1B: show respectively a view from below and from the side of a barrel fitted with the claimed device.

(3) FIG. 2: a modified view from below where, in contrast to FIG. 1 B, neither the cover plate nor the barrel is shown.

(4) FIGS. 3A and 3B each show a detailed perspective view of the positioning ring and of the return spring (from below).

(5) FIGS. 4A and 4B: a view from below and a sagittal sectional view of the barrel with illustration of the first device for the release of the winding rotations during the winding.

(6) In the following, simultaneous reference is made to the FIGS. 1A, 1B and 2 which show various views of the barrel 1 of a timepiece with an automatic winder according to a preferred embodiment of the invention. In particular, in FIGS. 1A and 2, the device for the limiting of the running rotations is emphasised in that the barrel 1 is shown in a blocking position.

(7) An ordinary barrel 1 is available for a timepiece with automatic winder. Locking wheel 2 on spring shaft 3 is located on the upper side. Turning the locking wheel 2 (first arrow direction a) to the left winds the mainspring 4. As soon as the spring 4 is completely wound around the spring shaft 3, the slipping bridle 4a of the mainspring slips along the drum inner wall 1a of the barrel 1. During the running, the barrel 1 also turns to the left (second arrow direction b), during which the spring shaft 3 is stationary. With that, the driving tooth system 1c drives the movement and any other connected modules, e.g. the calendar circuit.

(8) The claimed device 10 is preferably step-shaped and located under the base 1b of the barrel 1. On the one hand, it is hidden on the workplate after fitting and more easily accessible when assembling as it is not partially hidden by the locking wheel 2. As shown in FIG. 1B, the claimed device 10 comprises preferably two separate devices, each of which is intended for a particular function; namely, a first device 10a for the release of wind rotations and the second device 10b for the limiting of the number of running rotations of the barrel 1. The first device 10a works in a first placement plane A and the said second device 10b works in a second, separate placement plane B so that each desired function can be performed in a corresponding, dedicated placement plane, so that the additional modules can be set up step-by-step without having any effect on the normal drum-locking wheel structure of the barrel.

(9) The device 10, according to the preferred embodiment of the invention, contains one positioning ring 5 rotatably mounted on the barrel 1, the said ring also being illustrated in detail in FIG. 3A, and is involved both in the first device 10a and the second device 10b. This positioning ring 5 is stacked between the base 1b of the barrel 1 and an added cover plate 11 and seated on a shoulder that is not shown (e.g. vertical, cylindrical wall sections on the underside of the barrel 1). The cover plate 11 that is arranged as a deeper, double base for the barrel 1, is preferably fixed to barrel 1 using the screws 12for example three as shown in FIGS. 1A and 2and has preferably a cutout 17 in order to fix a return spring 15 to the barrel 1 by means of a shoulder pin, the said return spring 15 interacting with the first pin 9 during winding up. The return spring 15 and the first pin 9 form one preferred embodiment for the first device 10a for the release of the winding rotations. As shown in FIG. 1B, this first device 10a works in the first placement plane A, and its precise functioning is explained in more detail with the aid of the FIGS. 4A-4B.

(10) As shown in FIGS. 1A, 2 and 3A, the positioning ring 5 has an inner set of toothing 5a that meshes with a gearwheel 6 and has at its outside edge a divergence between a first locating surface 13 and a second locating surface 13. The said divergence simply forms a circular section whose radius is smaller than that of the remaining circular edge. The two locating surfacesthat is the first locating surface 13 and the second one 13are so formed. The interaction of a second pin 14 with the first locating surface 13 forms in a similar way a preferred embodiment for the second device 10b that works in the second placement plane B. In FIGS. 1A and 2, the barrel 1 is shown in an already locked position as the second pin 14 is supported on the locating surface 13 and a further running in the second arrow direction b is blocked.

(11) The positioning ring 5 shown in FIGS. 1A, 2 and 3A has an inner toothing 5a with a total of 17 teeth which defines the maximum number of running rotations. These inner toothing 5a meshes with a gearwheel 6 that has 13 teeth and the latter, in turn, engages with a placement finger 8 on the other side. This means that the positioning ring 5 can be indexed by one tooth to the right or left, either during the winding up of the barrel 1 (first arrow direction a for the entire gear chain placement finger 8-gearwheel 6-positioning ring 5) or in the opposite direction during the running of the barrel (second arrow direction b for the gear train barrel 1-gearwheel 6-positioning ring 5). In the position of the positioning ring 5 shown in FIGS. 1A, 2, it can be seen that no further shifting of the positioning ring 5 to the right in arrow direction b is possible, not only because the second pin 14 on the barrel 1 hits the first locating surface 13 but because there is no further tooth on the left side of the inner toothing 5a.

(12) According to the preferred, illustrated embodiment, the divergence between the first locating face 13 and the second locating face 13 is symmetrically arranged relative to the inner toothing 5a, i.e. this divergence extends over an angular section of the same value such as the inner toothing 5a of the positioning ring 5 so that the second pin 14 would hit the opposing second locating surface 13 in a similar way in the winding up direction (as in first arrow direction a), if the gearwheel 6 would engage with the last right tooth of the inner toothing 5a. This therefore ensures a dual protection for the rotational lock in both directions; this last lock is however never used thanks to the arrangement of the first pin 9 in the angular sector between the two locating surfaces (13 and 13) because the first device 10a is always actuated first.

(13) To improve the reliability of the device 10 relative to the placement of the rotational position of the rotatable positioning ring 5 mounted on the barrel 1, an indexing mechanism also exists that is made in the preferred embodiment by a detent spring 7 that engages between the meshing teeth of the gearwheel 6. This mechanism works in the second placement plane B, i.e. directly in the plane of the positioning ring 5, and therefore does not intrude into the inner space of the barrel. Such a compact arrangement outside the barrel 1 does not therefore disturb its normal operation and requires hardly any additional space that could be used for other parts in the timepiece.

(14) FIGS. 3A and 3B show a preferred embodiment for the positioning ring 5 and the return spring 15 where the return spring 15 has approximately a U-shape and is such arranged that it is attached to the barrel 1 with a shoulder pin 16. The return spring 15 has a longer arm fitted with a tip 15a which forms a part of this spring component that protrudes beyond the edge of the cover plate 11 (see, for example, FIG. 1A) and can interact with the first pin 9 attached to the positioning ring 5. Such an arrangement allows the restoring force of the spring tip 15a to be maximised. The first pin 9 lies at an angle between the first locating surface 13 and the second locating surface 13 so that this pin 9 hits the return spring 15 when the barrel 1 is wound up, before the second pin 14 is blocked by the second locating surface 13 as a minimum distance D exists between the second pin 14 and the second locating surface 13 when winding up. This minimum distance D is shown in FIG. 4A and is also reached in that the angle between the return spring 15 and the second locating surface 13 is greater than the angle between the two locating surfaces (in each case, the first locating surface 13 and the second locating surface 13), i.e. if the return spring 15 in the running blocked position of the barrel 1 sits behind the second pin 14 in the running direction (in the second arrow direction b) as shown in FIG. 1A. In the next paragraph, the winding up operation is explained in detail for the barrel 1 that is fitted with the invention-related device 10, in that reference is made both at the beginning of the winding up in FIGS. 1A and 2 and in FIGS. 4A and 4B at the end of the winding up where the first device 10a is used for the release of the winding up rotations.

(15) As illustrated in FIGS. 1A and 2, the positioning ring 5 is located on the underside of the barrel 1 and seated on a shoulder concentric with barrel 1. The said ring meshes with a gearwheel 6 whose rotary axis 60 is preferably located on the barrel drum in order to facilitate the fitting of the module. The gearwheel 6 is held at a defined indexed position by detent spring 7. The placement finger 8 is supported on the square section of the spring shaft 3. The axial support of gearwheel 6 and placement finger 8 is achieved using the cover plate 11, which is fixed to the barrel 1 by the screws 12. According to an alternative embodiment, the rotary axis 60 of the gearwheel 6 is also attached to this plate. This placement finger 8 performs each movement just like the spring shaft 3. After each complete rotation of spring shaft 3 and placement finger 8 in the arrow direction a, the gearwheel 6 is rotated further by one index position; at the same time, this ring is rotated further by one position in the first arrow direction a, i.e. the winding direction, defined by the tooth-meshing between gearwheel 6 and positioning ring 5. The position shown in FIGS. 1A and 2 is actually the last left tooth of the inner toothing 5a in the meshing with the wheel 6 so that the positioning ring 5 can only turn in the winding direction; the first locating surface 13 would be blocked anyway in the opposite arrow direction b (i.e. time running direction) by the second pin 14 attached to the base 1b of the barrel 1. The winding operation can therefore be started in this position.

(16) With the number of rotational movements of the positioning ring 5 dependent on the gearing ratio between gearwheel 6 and the positioning ring 5, the pin 9 firmly fixed to the positioning ring 5 reaches the long spring arm of the return spring 15, or more precisely, the tip 15a of this long arm, which protrudes from the outer edge 11a of the cover plate 11. With a further turning of the spring shaft 3, the index finger 8 attempts to further switch the positioning ring 5. In this, the long spring arm of the return spring 15 is tensioned by the pin 9 on the positioning ring 5, as illustrated in FIG. 4A. In the position shown, the barrel 1 has not rotated in comparison with FIG. 1Aboth the second pin 14 and the cutout 17 are in the same rotational positions. On the other hand, it can be seen that the gearwheel 6, which is also at the same position as detent spring 7, is indexed in a certain position, but now with the last teeth on the opposite side engaging with the inner toothing 5a. The interaction of the first pin 9 with the return spring 15 forms a preferred variant of the first device 10a for the release of the winding up rotations.

(17) Namely as soon as the placement finger 8 has left the meshing with the gearwheel 6, the return spring 15 can press back the positioning ring 5 by overcoming the spring force of the detent spring 7. Such a prerequisite is easily fulfilled thanks to the advantageous arrangement of the return spring 15, as it tries to maximise the restoring force.

(18) After this operation, which can be repeated any number of times, the return spring 15 is again relaxed, wherein it however still remains in contact with the second pin 14 until the next rotation of the spring shaft 3. The mainspring 4 of the barrel 1 shown in FIG. 4B can therefore be further tensioned and is only restricted when the slipping bridle 4a of this mainspring 4 slips at the drum inner wall of the barrel 1, i.e. only when the maximum allowable torque is reached.

(19) FIG. 3B shows a sagittal sectional view C-C of the barrel 1 that illustrates a tensioned mainspring 4 and the various placement planes for this preferred embodiment that is presented. Down at the bottom lies the locking wheel 2 that is torque-proof attached to the mainspring 3. The cover plate 11 is located at the uppermost level, the cutout 17 in the said plate for fixing the return spring 15 is shownimplemented here with the help of the shoulder pin 16. The level of the cover plate forms the first placement plane, wherein the return spring 15 which interacts with the first pin 9 (the pin 9 is not shown in this figure). As already mentioned, the second placement plane B containing the placement finger 8 and the fitted rotatable positioning ring 5, lies between the cover plate 11 and the barrel 1.

(20) The barrel 1 can be turned back from the position shown in FIG. 4A during the running to the position in FIGS. 1A and 1B. Namely during the running, the barrel 1 rotates in the second arrow direction b, i.e. in the running direction. The spring shaft 3 remains stationary during this. After one rotation of the barrel 1, the rotatable gearwheel 6 mounted on the barrel 1 reaches the placement finger 8. In this rotating movement, the gearwheel 6 is turned by the placement finger 8 though one index position in the arrow direction b. At the same time, due to the gear meshing between gearwheel 6 and the positioning ring 5, this indexes further by one position in the second arrow direction b.

(21) This operation can be repeated so often till, due to the rotation of the positioning ring 5, the locating surface 13 on the positioning ring 5 reaches the second pin 14 that is firmly attached to the barrel 1. This blocks the rotational movement of the barrel 1 in the second arrow direction b relative to the spring shaft 3 and both the barrel and all members of the device 10 are located at the position shown in FIG. 1A.

(22) Someone skilled in the art will however understand from this description that the subject matter of the present invention covers other variants for the claimed device 10, namely with parts other than a positioning ring 5, other types of pins and stops that are located in other placement planes, and possibly designed as single parts that are not necessarily fixed to these. It can be understood especially that the first device 10a for the release of winding up rotations can function with any spring-loaded stop, wherein the spring element does not have to be located on the barrel 1; for example a spring-loaded instead of a rigid pin could be attached to the positioning ring 5, or vice versa a rigid finger instead of the return spring 15 on the barrel 1. The maximum number of running rotations can be adjusted as required and the transmission ratios between all gearing elements can also be adapted as required. Other aspects such as various materials (not just steel), forms and expansion direction for the spring-loaded stop of the first device 10a are quite possiblewithout exceeding the scope of the invention.

(23) Someone skilled in the art will also understand that the present invention is not only limited to timepieces with automatic winding, but can also be adapted to movements with hand winder. The maximum allowable winding in the mainspring is then determined by the fixing hook instead of being limited by the slipping bridle, but never affected by the claimed device.

(24) The detailed, preferred embodiment mentioned is therefore only to be regarded as an example and should not be construed as a restriction on the interpretation of the claims.

LIST OF REFERENCE NUMBERS

(25) 1 barrel 1a inside wall of the drum 1b base 1c driving tooth system 2 locking wheel 3 spring shaft 4 mainspring 4a slipping bridle 5 positioning ring 5a inner toothing 6 gear wheel 60 rotational axis of the gear wheel 7 detent spring 8 placement finger 9 first pin 10 device for limiting the number of running rotations with any number of winder rotations 10a first device for the release of winder rotations 10b second device for the limiting of running rotations 11 cover plate 11a outer edge of the cover plate 12 screws 13 first locating surface 13a second locating surface 14 second pin 15 return spring 15a tip 16 shoulder pin 17 cutout (in cover plate) a first arrow directionwinding direction of the barrel b second arrow directionrunning direction of the barrel A first placement plane of the first pin 9 B second placement plane of the second pin 14 C-C section direction for FIG. 4B D minimum distance between pin 14 and the second locating surface 13 during winding