GB2086101A - Mechanical Time-Setting Device for a Watch Having Analogue Time Indication - Google Patents

Abstract

The time-setting device comprises a key and a time-setting gear train. The key comprises a cylindrical shaft 112'' rotatably mounted and sliding in a tube integral with the back 6 of the case. A mutilated toothed wheel 118 is fixed to the inner end of the shaft. A blade 116 is mounted for pivotal movement about the outer end of the shaft 112''. The blade 116, in the folded back position, can be introduced into a seating 126 formed in the back of the case. A return spring 140 normally maintains the wheel 118 above the adjusting wheel 22. When the blade 116 is in the angular position for being introduced into the seating 126, the un-toothed recess 118c of the multilated wheel 118 is directed towards the wheel 22 so that the teeth of the wheels 22 and 118 do not clash when the shaft 112'' is pulled out by the blade 116 for time-setting by turning the blade and shaft. After release of the blade, the spring 140 returns the shaft and wheel 118 to the retracted position (Figure 3a) in which the blade can be freely rotated for introduction into the seating 126. <IMAGE>

Description

SPECIFICATION Mechanical Time-setting Device for a Watch Having an Analogue Time Indication The present invention relates to a mechanical time-setting device for a watch having analogue time indication.

More specifically, the invention is concerned with a mechanical time-setting device which will be suitable for use in a watch of small thickness and which will no longer be visible when this watch is worn on the wrist.

It is well known that mechanical watches are provided with an operating member for setting the time, which usually also serves for winding the watch. In the case where these two functions are performed by the same member, the operating member usually has the form of an operating shaft or winding shaft which is slidable in the case and in the plate of the movement. This shaft, by means of levers actuates a sliding pinion, meshes either with the time-setting means or with the crown wheel for the winding. In order to enable the user to manipulate the shaft easily, the latter is provided with a winder head or crown which projects from the rim of the watch case.

In the case of electronic watches with analogue time-indication, the time setting of the watch can be effected with the aid of one or more push buttons which project from the outer rim of the watch. In this same case, the time setting can equally well be effected by means of a rod which is slidable to several different positions, as is done in mechanical watches.

It is clear that, in general, the projecting part which is formed by winding crown or the push button does not constitute the most decorative part of the watch. It is also altogether clear that, in the case of a very thin watch, the winder or push button is all the more noticeable if the crown or push button has dimensions which render it easily operable. It would not therefore be advantageous to be able to locate this member in such a manner that it will not be visible when the watch is being worn.

It is for this reason that certain electronic watches having analogue-time indication have in the back of the case a small push button which, when it is depressed, causes pulses to be transmitted to the electric motor. In the rest condition, the head of this push button is flush with the outer surface of the back of the case.

However, in the case of very flat watches, the head of the push button can have only a very small surface area. This makes manipulation a relatively delicate operation since it is necessary at one and the same time to keep an eye on the dial of the watch and to actuate the push button.

Moreover, this solution is certainly not applicable to the control of mechanical watches.

Furthermore, a certain number of watches exist in which operating member serves only for setting the time. This is the case with automatically wound mechanical watches in which a winding weight enables a manual winder to be dispensed with. It is also the case with electronic watches having analogue disp!ay means which serve only for indicating the time. It is also the case in mechanical watches if a special operating means is provided for manual winding. It is therefore clear that a device which provides for the operation of only the time-setting of the watch and which in addition will not be visible is of real interest.

Accordingly a first object of the invention is to provide a device for time setting only which will not be visible when the watch is worn by its user and which does not involve any discomfort in order to achieve this end.

A second object of the invention is to provide a time-setting device which will be easy to manipulate and which does not necessitate the use of a special tool.

A third object of the invention is to provide a device of this nature which will also be suitable for use with a very thin watch, for example a watch the overail thickness of which is less than 2 mm.

A fourth object of the invention is to provide a device of this nature which will in addition be suitable for use with a self-winding watch.

According to the present invention, there is provided a watch having analogue time indication and comprising a going train in a case with a back, and a time-setting key including a shaft mounted rotatably and slidably through the back and resiliently axially biased to a retracted position, a blade for turning the shaft pivotaily attached to the outer end of the shaft for movement between a swung-out, operating position and a flush position in which the blade is received in a seating in the back, and a gear on the inner end of the shaft which is in meshing alignment with a wheel of the going train only when the shaft is pulled out from the retracted position but which is so mutilated that there is no meshing while the shaft is in that angular position in which the blade can enter its seating.

For setting the time, a pull is applied to the shaft by way of the blade to bring the mutilated gear opposite the time-setting wheel but with a toothless recess opposite the time-setting wheel.

Then, while maintaining the pull on the shaft, the blade and shaft are rotated to bring the hands (say) to the desired position. The pull is then released, as a result of which the mutilated gear moves out of meshing alignment with the timesettingwheel. While rotating the shaft, the blade is then replaced in its seating. The mechanism is now in its rest position, ready for effecting a new time-setting operation when required.

It is clear that the time-setting device is wholly withdrawn into the back of the case except during the time-setting periods. However, when the blade is in the swungout position, the user can easily proceed with the time-setting of the watch, since the blade then projects a substantial distance out of the back of the case. Moreover, the seating defines the rest position of the timesetting wheel, which avoids any problem of moving the toothed wheels into engagement for another time-setting operation without complicating the mechanism for this purpose. In addition, the time-setting transmission means, that is to say the time-setting gear train, can be located near the back of the case.

The invention will be described in more detail, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a top view of a self-winding watch provided with the time-setting device according to the invention; Figure 2 is a partial bottom view of the watch case showing the time-setting device; Figures 3a and 3b are half views in vertical section of the time-setting key, taken on the line Ill-Ill of Figure 2 in its two operating positions respectively; Figure 4 is a partial top view of the back of the case showing the time-setting key; Figure 5 is a view in vertical section of one of the moving parts of the time-setting gear train, taken on the line V-V of Figure 1; and Figure 6 is a diagram illustrating the kinematics of the watch shown in Figure 1.

Figure 1 shows, in top view, an extra thin selfwinding watching provided with a time-setting device in accordance with the invention.

Moreover, in this watch the back of the case constitutes a plate of the movement.

On the back 6 of the case, a winding weight 10 comprising an oscillating mass lOb and an arm 1 Oa is mounted for pivotal movement about a pivotal axis coincident with the axis of a toothed annulus 12. The movement of the winding weight is transmitted to the toothed annulus 12 by an arrangement of two pawls. This annulus is drivably connected to the ratchet 14 of a spring barrel 20 by wheels 16 and 18. The spring barrel 20 is drivably connected to a hand-driving wheel 24 by a wheel 22. The hand-driving wheel 24 is in mesh on the one hand with a centre wheel 26 and on the other hand with a cannon wheel 28. The hand-driving wheel 24 is also in mesh with the final wheel 32 of a gear train 32, 34, 36 and 38, the wheels of which are rotatably mounted on a lower bridge plate 100. The escapement wheel 38 cooperates with a lever/balance-wheel/hair spring assembly 30.Lastly, the watch includes an assembly 110 which forms the time-setting key.

The operation of the watch, except during time-setting periods is as follows. The pivotal movement of the winding weight 10 under the action of the movements of the watch causes the toothed annulus 12 to rotate, always in the same direction, which thus effects the winding up of the spring of the spring barrel. The spring barrel, by means of the wheel 22 and the hand-driving wheel 24, rotationally drives the hands carried by the cannon wheel 28 and the centre wheel 26.

The construction of the watch and its going train in particular are described in more detail in our copending application of even date No.

8131824 and Ser. No. (claiming priority from Swiss Patent Application 7 961/80-0).

Figures 2 to 4 show one constructional form of the time-setting key 110. As shown in Figure 3, the key 110 includes a cylinder 112' which extends through the back 6 of the case and is rotatably mounted in a tube 114 which forms an integral part of the back 6 of the case. The cylinder 112' constitutes a shaft which is also axially slidable in the tube 114. At its outer end, the cylinder 112' has a blade 116 which is mounted for pivotal movement about an axis XX, X1' perpendicular to the axis Yr, Y1, of the cylinder 112'. At its inner end, that is to say at the end thereof which extends into the case of the watch, the cylinder 112' is provided with a toothed wheel 11 8, the axis of which is coincident with the axis Y1, Y1,.

The blade 116 has, for example, the form of an isosceles triangle, the apex of which is extended by two arms 120 and 120'. The arms 120 and 120' are provided with cylindrical swivel pins 122 and 122'. The cylinder 112' has an axial bore 11 2a. In addition, the outer end of the cylinder 112' has two notches (not shown) disposed along the axis X1, X,'. The swivel pins are engaged in these notches. A bolt 124 is engaged as a force fit in the outer end of the bore 11 2a. The head of the bolt 1 24 closes these notches. The swivel pins 122 and 122' are thus confined within the notches. The blade 11 6 can pivot about the axis xl, X,'.Furthermore, the diameter of the shank of the bolt 124 is sufficient to enable the ends of the swivel pins 122 and 122' to grip the shank of the bolt in such a manner that the blade 11 6 cannot pivot about the axis X,' unless an external force is applied to it. In addition, the external surface 6a of the back 6 of the case is provided with a seating 126 which is of substantially the same shape as the blade 11 6. Moreover, the depth of this seating is substantially equal to the thickness of the blade 11 6. Thus, when the blade 116 is folded back, that is to say when the blade is positioned in the seating 126, it does not project outwardly from the external surface 6a of the back 6 (of the case).

It will be appreciated that, the same applies to the head of the bolt 124. This is of course the rest position. However, when the blade 11 6 is raised in the direction of the axis Y1,Y1,, it projects to a considerable extent outside the external surface 6a of the back 6a of the case. It is then easy to grasp with the tips of the fingers in order to turn the cylinder 112' about its axis Y1,Y1'. This is the operative position of the blade.

The recess 126, which is of substantially the same shape as the blade 116, additionally produces a precise angular position of the cylinder 112" about its axis1, Yr' when the blade 116 is engaged in the seating 126.

The toothed wheel 11 8 is mounted on the inner end of the cylinder 112" in the following manner. The end of the cylinder 112" has two parallel flats. The axial bore of the wheel 11 8 has two corresponding flats 11 8b and 11 8'b. These flats 11 8b and 11 8'b cooperate with the flats on the cylinder and the wheel is held on the cylinder 11 2' by a bolt 1 29 which is force-fitted in or screwed into the axial bore 11 2a of the cylinder. It is clear that, when the blade 11 6 is raised, it is possible to rotate the toothed wheel 11 8 about the axis Y1,Y1,.

As shown in Figure 1 , the wheel 118 can mesh with the wheel 22 which thus also serves as a time-setting gear. However, the wheel 11 8 is mutilated, being devoid of teeth over a portion of its periphery corresponding to a recess 11 8c. It is to be noted that this recess 11 8c is opposite the wheel 22 only when the cylinder 112" has an orientation such that the blade 116 can in fact be introduced into the seating 126.This possibility exists only in one angular position of the cylinder 112" since the arms 120 and 120' have inclined portions 1 20a, 1 20'a corresponding to the thickness of the head of the bolt 1 24. These prevent the blade being closed down into its recess when the cylinder 112" is 1800 away from the said one angular position.

This part of the construction of the key is described in greater detail in our patent application fiied today under the No. 8131825, Ser. No. (claiming priority from Swiss Patent Application 7 962/80-0).

The key includes in addition, as can best be seen in Figures 3, a return spring 140. One end of this spring is rigid with the back of the case 6. The other end of the spring 140 has the form 118. In the rest condition, as shown in Figure 2a, the spring 140 holds the wheel 118 above the timesetting wheel 22 and the blade 11 6 can be introduced into its seating 1 26. The key assembly is thus flush with the external surface 6a of the back 6 of the case. However, if a pull is applied to the cylinder 112" by means of the blade 116, it is possible to bring the wheel 11 8 opposite the wheel 22.

The manner in which the time-setting device operates follows clearly from the preceding description. Except during the time-setting periods, the blade 11 6 is in its seating 1 26. The wheel 11 8 is then in its upper position, that is to say above the moving part 22. When the user of the watch wishes to effect an adjustment of the time setting, he prises the blade out of its seating and applies a pull to the cylinder 112" so as to bring the wheel 11 8 into the same plane as the moving part 22. This does not give rise to any meshing problem since, the cylinder 112" not having been rotated, the recess 11 8c is opposite the moving part 22. Without relaxing the pull, the user next rotates the cylinder 112" until the hands occupy a suitable position.He then releases the pull. Under the action of the spring 140, the wheel 11 8 re-assumes its position above the moving part 22. Lastly, the user causes the cylinder 112" to rotate to the angular position which allows him to snap the blade 116 back into its seating. This completes the time-setting operation. It is essential to note that, thanks to the offset of the arms 120 and 120' due to the inclined portions 1 20a and 120'a, there is only one single angular position in which the blade can be inserted into its seating.

Figure 6 shows the kinematics of the train of wheels which makes possible the time setting of the hands to be adjusted as a result of the rotation of the wheel 11 8. The wheel 22 is constituted by two gears 22a and 22b. The gear 22a is rigid with its arbor whereas the gear 22b is freely mounted on this arbor. A friction device F is interposed between the gears 22a and 22b. The hand-driving wheel 24 comprises a wheel 98 and a pinion 96 which are rigid with the arbor of the moving part, while a second wheel 1 30 is freely mounted on the arbor. The wheel 130 is drivably connected with the wheel 98 by a friction device F'. The time-setting wheel 11 8 is in mesh with the gear 22a of the wheel 22. The gear 22b is in mesh with the wheel 98 of the driving wheel 24.Lastly, the wheel 98 is in mesh with the centre wheel 26, the wheel 130 is in mesh with the first moving part 32 of the final gear train and the pinion 96 is in mesh with the cannon wheel 28.

During normal operation (without time setting) the friction devices F and F' lock together the wheels 22a and 22b on the one hand and the wheels 98 and 130 on the other hand. Moreover, the time-setting wheel 11 8 is not in mesh with the wheel 22a. The movement of the spring barrel is therefore transmitted to the hand-driving moving part and the movement of the handdriving moving part to the final gear train.

In the case of time setting, the wheel 11 8 is in mesh with the wheel 22a, but the opposing torque developed by the spring barrel is sufficient to uncouple the wheels 22a and 22b, overcoming the effect of the friction device. Consequently, the rotation imparted to the wheel 22a by the wheel 118 is not transmitted to the wheel 22b and the spring barrel is not driven thereby. Likewise, the wheel 22a is in mesh with the wheel 98, but the opposing torque developed by the final gear train is sufficient to uncouple the wheels 98 and 130 of the hand-driving moving part 24, overcoming the effect of the friction device F'. Thus, the movement of the wheel 22a is not transmitted to the final gear train 32.Consequently, the action on the wheel 11 8 produces the turning of the hands by means of the wheel 28, but it leaves the spring barrel 20 and the escapement 30 stationary.

Figure 5 shows one possible constructional arrangement of the hand-driving wheel 24. The latter is mounted for rotation on an arbor 92 which is a force fit on a projection 90 which forms an integral part of the back 6 of the case. The moving part 24 comprises the pinion 96 mounted on the arbor 92 by means of a bearing 94. The pinion has a series of peripheral teeth 96a and a shoulder 96b located between the teeth 96a. The first toothed wheel 98 is engaged as a force fit on the pinion at the level of the shoulder 96b. The second toothed wheel 1 30 is freely mounted on the body of the pinion below the wheel 98. The wheel 130 is retained in position by a washer 132 which is engaged as a force fit on a second shoulder of the pinion 96. The friction device F' is interposed between the wheels 98 and 130.It is for example a case of a member having a large number of radial arms which are bent over alternately towards the wheel 98 and towards the wheel 130.

It is clear that the blade 11 6 serves a dual role.

On the one hand, when it is in the operative position, it enables the time-setting wheel to be rotated so as to effect the desired displacement of the hands; on the other hand, when it is located in its seating, it serves for fixing the angular position of the key so that the recess in the time-setting wheel is aligned opposite the wheel 22 so that pure axial movement of the shaft 112" does not involve any meshing of the wheels 118 and 22.

This arrangement is particularly important in the case of a watch of very small thickness. In fact, in such a case, having regard to the very small thickness of the wheels, for example one or a few tenths of a millimetre, it is extremely difficult to form the teeth of the wheels so as to permit meshing engagement of two wheels when one of them is displaced translationally along its rotational axis. Thanks to the invention, when the two wheels are brought opposite each other, no problem of meshing engagement occurs since it is the recess of 11 8c of the wheel 118 which comes opposite the moving part 22.

Besides, the fact that the wheel 11 8 is in mesh with the moving part 22 when it is in the retracted position, that is to say close to the back of the case, make it possible to locate the timesetting gear train very near the back of the case, which is essential in order to produce a very flat watch. Lastly, this solution makes it possible to avoid having to hollow out a seating of comparatively great depth in order to allow for the translational movement of the cylinder 112". This is very important because the back 6 must have a very small thickness of a few tenths of a millimetre.

The preceding description is concerned with an automatically wound watch with time indication by means of hands. This is in fact the most advantageous field of application of the mechanical time-setting device that is the subject of the invention. However, the application of this device is in no way limited to this type of watch.

The key can perfectly well be utilized in a mechanical watch with time-indication by means of disks, only the time-setting gear trains possibly being different. It can likewise be utilized in an electronic watch in which, as is well known, the spring barrel is replaced by a stepping motor and the escapement is eliminated.

It follows from the description that the timesetting device does in fact enable the objectives that are sought after to be attained. It should be noted in particular that, except during the timesetting periods, the time-setting key is wholly retracted into the back of the case and that, when the blade is removed from its seating, it provides a handhold sufficient to enable the user of the watch to effect the adjustment of the time setting easily.

It must also be stressed that the amplitude of the translational movement of the cylinder 112" is small, which enables it to be mounted in a watch of small thickness. Moreover, the spring 140 is not compressed except during very brief periods, which limits the stresses that are applied to it.

Finally, there is no machining of the guide tube 114 for the cylinder 112", which likewise renders this solution suitable for use with a watch of very small thickness, for example less than 2mm.

Claims (6)

Claims

1. A watch having analogue time indication and comprising a going train in a case with a back, and a time-setting key including a shaft mounted rotatably and slidably through the back and resiliently axially biased to a retracted position, a blade for turning the shaft pivotally attached to the outer end of the shaft for movement between a swung-out, operating position and a flush position in which the blade is received in a seating in the back, and a gear on the inner end of the shaft which is in meshing alignment with a wheel of the going train only when the shaft is pulled out from the retracted position but which is so mutilated that there is no meshing while the shaft is in that angular position in which the blade can enter its seating.

2. A watch according to claim 1, wherein the back has a guide tube for the shaft on its inside.

3. A watch according to claim 1 or 2, wherein the resilient bias on the shaft is provided by a leaf spring inside the case and having one end fixed to the back and the other end in the form of a fork engaging a groove in the shaft.

4. A watch according to claim 1,2 or 3, wherein the going train comprises a cannon wheel, a centre wheel, a final gear train, the said wheel of the going train and a further wheel, the said wheel of the going train comprising first and second frictionally coupled wheels and the further wheel comprising third and fourth frictionally coupled wheels and a pinion fast with the third wheel and in mesh with the cannon wheel, the first wheel being the wheel which meshes with the mutilated gear for time-setting and being in mesh with the third wheel, which is in mesh with the centre wheel, and the fourth wheel being in mesh with a wheel of the final gear train.

5. A watch according to claim 4, wherein the second wheel is driven by the source of motive power for the watch.

6. A watch with analogue time indication and a time setting device substantially as hereinbefore described and as illustrated in the accompanying drawings.