GB2266791A - Improvements relaating to chronographs - Google Patents

Improvements relaating to chronographs Download PDF

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Publication number
GB2266791A
GB2266791A GB9209925A GB9209925A GB2266791A GB 2266791 A GB2266791 A GB 2266791A GB 9209925 A GB9209925 A GB 9209925A GB 9209925 A GB9209925 A GB 9209925A GB 2266791 A GB2266791 A GB 2266791A
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Prior art keywords
member
engagement
wheel
chronograph
surface
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GB9209925A
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GB9209925D0 (en )
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George Daniels
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George Daniels
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    • GPHYSICS
    • G04HOROLOGY
    • G04FTIME-INTERVAL MEASURING
    • G04F7/00Apparatus for measuring unknown time intervals by mechanical means
    • G04F7/04Apparatus for measuring unknown time intervals by mechanical means using a mechanical oscillator
    • G04F7/08Watches or clocks with stop devices, e.g. chronograph

Abstract

There is provided a chronograph comprising a seconds elapsed indicator (78), a driving member (94) which in use is continuously rotated, a clutch member (98) mounted for rotation about an axis coaxial with the driving member (94) and actuating means to cause axial movement of the clutch member (98) and effect direct or indirect engagement between the driving member (94) and the seconds elapsed indicator (78). There is also provided a chronograph having at least one hand to indicate time and seconds elapsed indicator (78) mounted for rotation about an axis displaced from that of said at least one hand. There is also provided a device for advancing a wheel of time-piece comprising a pawl member (10) that when moved in a first direction engages and rotates the wheel (28), the pawl member (10) being constrained to move in a direction transverse to but having a component in the said first direction. <IMAGE>

Description

IMPROVEMENTS RELATING TO CHRONOGRAPHS The present invention relates to chronographs.

A conventional chronograph mechanism designed to start and stop a time elapsed indicator and which has provision to zero the indicator after use is fitted to the back plate of the time-piece in which the mechansim is accommodated. This necessarily increases the thickness of the movement as does the fact that the seconds elapsed indicator is conventionally mounted coaxially with the minute and hour hands of the time-piece and so must be raised in order to be free to rotate.

Furthermore, the conventional chronograph mechanism is started by the radial movement into toothed engagement of a wheel intermediate a seconds elapsed wheel and a continuously rotating seconds driving wheel. This method of engagement can cause the seconds elapsed indicator to jump or hesitate when first actuated if the radially engaging teeth of the seconds elapsed wheel butt on entering into engagement with the intermediate wheel.

According to a first aspect of the present invention there is provided a chronograph comprising a rotatable seconds elapsed indicator, a driving member which in use is continuously rotated, a clutch member mounted for rotation about an axis coaxial with the driving member and actuating means to cause axial movement of the clutch member and effect direct or indirect engagement between the driving member and the seconds elapsed indicator. This provides the adavantage that the seconds elapsed indicator is no longer subject to the possibility of irregular engagement with the means by which it is driven.

Advantageously the seconds elapsed indicator is mounted for rotation about an axis coaxial with the driving member.

Advantageously means are provided to bias the clutch member towards a position in which the driving member is in direct or indirect engagement with the seconds elapsed indicator and the actuating means serves to urge the clutch member against the said biasing means.

According to a second aspect of the present invention there is provided a chronograph having at least one hand to indicate the time and a seconds elapsed indicator mounted for rotation about an axis displaced from that of the said at least one hand.

This provides the advantage of enabling the movement of the chronograph mechanism to be reduced in thickness.

Advantageously the chronograph mechanism is accommodated between a top plate and a bottom plate of the chronograph.

According to a third aspect of the present invention there is provided a device for advancing a wheel of a time-piece comprising a pawl member that when moved in a first direction engages and rotates the wheel, the pawl member being constrained to move in a direction transverse to but having a component in the said first direction.

Advantageously the pawl member is in sliding engagement with the reference surface which is so adapted that on the application of a force to the pawl member the engagement with the reference surface imparts to the pawl member a component of movement transverse to the applied force sufficient to cause the pawl member to engage and rotate the wheel.

Preferably the reference surface comprises an inclined ramp contiguous with a substantially planar region so that having moved down the ramp the pawl member is prevented from further movement in the direction of the applied force by engagement with the substantially planar region thereby limiting the angular displacement of the wheel. Preferably the pawl member is provided with a resilient means that projects from a surface of the pawl member opposed to the reference surface and which is adapted to return the pawl member to its starting position upon release of the applied force. Preferably the reference surface is provided with a cutaway region to accommodate the resilient means when the pawl member is engagement with the substantially planar region.

An embodiment of the present invention will now be described by way of example with reference to the accompanying drawings in which: Figure 1 is a plan view of the mechanism of a chronograph in accordance with a first aspect of the present invention in which the mechanism is shown at rest and with certain parts omitted for the sake of clarity; Figure 2 is a plan view of the chronograph mechanism of Figure 1 in operation with certain parts again omitted for the sake of clarity; Figure 3 is plan view of part of the chronograph mechanism of Figure 1 showing the actuating mechanism in greater detail; Figure 4 is an exploded perspective view of another part of the chronograph mechanism of Figure 1 in which certain parts have been broken away for the sake of clarity; and Figure 5 is a lateral side view of the chronograph mechanism of Figure 1 in which certain parts have again been omitted for the sake of clarity.

Referring initially to Figures 1 and 3, the illustrated chronograph mechanism can be seen to comprise a pawl 10 in sliding engagement with a reference surface 12. The pawl 10 comprises a push button 14 on a surface of the pawl remote from the reference surface 12, a forwardly projecting portion 16, an arcuate spring portion 18 that projects forwardly from a surface of the pawl 10 remote from the push button 14 so as to engage a region of the reference surface 12, and a curved heel portion 20 remote from the forwardly projecting portion 16. By contrast the reference surface 12 comprises an inclined ramp 22 leading to a substantially planar region 24 in which there is provided an arcuate cutaway region 26.The push button 14 is disposed toward one end of the pawl 10 and in particular is disposed rearwardly of the point from which the arcuate spring portion 18 projects while the forwardly projecting portion 16 is shaped so as to be capable of releasably engaging a toothed pillar wheel 28.

The pillar wheel 28 is mounted for rotation about a shaft 30 substantially perpendicular to a front or back plate of the time piece and is prevented from riding up the shaft by means of a flanged head piece 32. On a circumferential surface 34, the pillar wheel 28 is provided with an even number of teeth 36 each having a profile comprising an inclined surface 38 and a radially directed surface 40 that form a ratchet prevented from clockwise rotation by the engagement between the teeth of an arm 42 of a spring 44. On an upper surface 46, the pillar wheel 28 is provided with a number of upstanding projections 48 equal to half the number of teeth 36 provided on the circumferential surface 34.These projections 48 resemble the castellations of a fortified tower and are disposed so as to lie adjacent alternate teeth 36, each castellation being part annular in cross-section and defined by inner and outer arcuate surfaces 50 and 52 and substantially radially-directed interconnecting surfaces 54 and 56. On an under surface 58, the pillar wheel 28 is provided with a similar number of indentations 60 each aligned with a respective one of the castellations 48 and again disposed so as to lie adjacent alternate teeth 36.

Disposed substantially parallel to the shaft 30, concentric shafts 62 and 64 are mounted for independent rotation in either direction. The inner of the two shafts 62 is longer than the outer shaft 64 and projects therefrom at opposite ends. To the lower of these ends is attached a minutes elapsed indicator 66 in the form of a radially projecting hand while at the opposite end there is provided a toothed wheel 68. A cam 70 is rigidly attached to an upper surface of the toothed wheel 68 and is provided with a pair of oppositely directed cam surfaces 72 and 74 that in cross-section diverge from a point at one end, each forming a mirror image of the other, and are interconnected at an opposite end by an arcuate surface 76. By contrast the outer shaft 64 is provided at its lower end with a seconds elapsed indicator 78 in the form of a radially projecting hand while at the oppsite end there is attached a disk plate 80. A second cam 82 is rigidly attached to an upper surface of the disk plate 80 and, like the first cam 70, is provided with a pair of oppositely directed cam surfaces 84 and 86 that in cross-section diverge from a point at one end, each again forming a mirror image of the other. As before, the two cam surfaces are interconnected at an opposite end by an arcuate surface 88. A second disk plate 90 is rigidly attached to an upper surface of the second cam 82 and carries a radially projecting finger 92.

Intermediate the ends of the outer shaft 64 a seconds driving wheel 94 is mounted for continuous, independent rotation on a loose-fitting, concentric sleeve 96 driven, either directly or indirectly, by the train of the time piece. Adjacent the seconds driving wheel 94 and again concentric with the outer shaft 64 there is mounted an axially sliding clutch 98 comprising a top plate 100 and a bottom plate 102 interconnected by a loose-fitting collar 104. A leaf spring 106 is disposed between the bottom plate 102 and an abutment 108 provided on the outer shaft 64 and serves to urge the clutch 98 upwardly into engagement with the seconds driving wheel 94.This upward movement is resisted by the action of a touch-piece 110 comprising an elongate member pivotable about an axis 112 substantially perpendicular to the concentric shafts 62 and 64 and disposed at an end of the member remote from the clutch 98. The touch-piece 110 additionally comprises a frustro-conical boss 114 carried by the elongate member and adapted to engage the under surface 58 of the pillar wheel 28.

A lever mechanism 116 comprising upper and lower zeroing levers 118 and 120 and a jump lever 122 is disposed intermediate the pillar wheel 28 and the two concentric shafts 62 and 64. As can best be seen from Figure 4, all three of the levers making up the lever mechanism 116 are mounted for rotation about a single shaft 124 disposed substantially parallel to the shaft 30 of the pillar wheel 28, the upper and lower zeroing levers 118 and 120 being aligned and integrally connected by a body portion 126 so that they rotate together.

Referring to Figures 1, 2 and 4 the jump lever 122 can be seen to comprise an arm pivoted at one end and terminating at the other in an angled portion 128 shaped to engage the teeth of the toothed wheel 68.

This engagement is facilitated by the action of a blade spring 130 that extends between a lateral projection 132 provided at the proximal end of the jump lever 122 close to shaft 124 and an anchoring post 134 attached to the front or back plate of the time piece. By contrast the upper zeroing lever 118 comprises a leg-like member having a substantially planar surface 136 on what would be the bottom of the foot. The lower zeroing lever 120 is of a similar shape and likewise comprises a leg-like member having a corresponding planar surface 138.

The body portion 126 interconnecting the upper and lower zeroing levers 118 and 120 is disposed between the planes of the levers and comprises a first cam surface 140 for engagement with the castellations 48 of the pillar wheel 28, a second cam surface 142 for engagement with a locking spring 144 and a laterally projecting tail 146. The laterally projecting tail 146 is shaped so as to engage an arcuate surface 148 provided on one limb of an otherwise substantially bi-concave lever 150. The lever 150 is pivotally mounted about a central axis 152 disposed substantially parallel to the shaft 30 of the pillar wheel 28 and may be rocked to sandwich a tab portion 154 between the other limb of the lever 156 and a concave surface 158 provided on the locking spring 144.This tab portion 154 is connected at an end remote from the lever 150 to a supporting bracket 160 and a second blade spring 162, the supporting bracket 160 carrying at its distal end an intermediate toothed wheel 164 mounted for rotation about an axis 166 disposed substantially parallel to that of the two concentric shafts 62 and 64. By contrast at an end remote from the tab portion 154 the blade spring 162 bears against to the front or back plate of the time piece.

The locking spring 144 is rigidly attached at one end to the front or back plate of the time piece and in addition to the concave surface 158 is provided towards its distal end with a projecting guard portion 168 that overlies the lever mechanism 116 and prevents the mechanism from riding up its shaft 124.

The locking spring 144 is also provided with an angled surface portion 170 comprising first and second inclined surfaces 172 and 174 for engagement with the second cam surface 142 of the body portion 126. Likewise, spring 44 is also rigidly attached at one end to the front or back plate of the time piece and in addition to arm 42 is provided with a second limb having at its distal end a head piece 176 and, on a surface opposed thereto, a second push button 178.

Figure 1 shows the chronograph mechanism at rest with the minutes elapsed and seconds elapsed indicators 66 and 78 registering zero. In this state the pillar wheel 28 is prevented from rotating on its shaft 30 by the engagement of arm 42 between the teeth 36. The inner of the two concentric shafts 62 is prevented from rotating by both the engagement of the angled portion 128 of the jump lever 122 between the teeth of the toothed wheel 68 and the engagement of the planar surface 136 of the upper zeroing member 118 with the arcuate surface 76 of the first cam 70.

Likewise, the outer of the two concentric shafts 64 is prevented from rotating by both the friction that exists between the leaf spring 106 and the abutment 108 and the engagement of the planar surface 138 of the lower zeroing member 120 with the arcuate surface 88 of the second cam 82. Only the seconds driving wheel 94 rotates, driven either directly or indirectly by the train of the time piece.

When the mechanism is at rest the frustroconical boss 114 carried by the touch-piece 110 engages the under surface 58 of the pillar wheel 28 at a point between two of the indentations 60. This engagement causes the touch-piece 110 to compress the leaf spring 116 thereby preventing the engagement of the clutch 98 with the seconds driving wheel 94. As for the lever mechanism 116, the jump lever 122 is prevented from rotating about shaft 124 by the action of the blade spring 130 while the upper and lower zeroing levers 118 and 120 are prevented from rotating about the same shaft by the engagement of the angled surface portion 170 of the locking spring 144 with the second cam surface 142 of the body portion 126.With the body portion 126 in this position the projecting tail 146 engages the arcuate surface 148 of the bi-concave lever 150 causing the other limb of the lever 156 to hold the tab portion 154 against the concave surface 158 of the locking spring 144. As a result the intermediate toothed wheel 164 is held away from the toothed wheel 68 against the action of the second blade spring 162.

To actuate the chronograph mechanism push button 14 is depressed causing the pawl 10 to move toward the reference surface 12 against the action of the arcuate spring portion 18. Since the push button 14 is disposed rearwardly of the point from which the arcuate spring portion 18 projects, by depressing push button 14 the heel portion 20 is made to slide down the inclined ramp 22 imparting to the pawl 10 a component of movement transverse to the direction of the applied force and sufficient to cause the forwardly projecting portion 16 to engage between adjacent teeth 36 of the pillar wheel 28. Continued downward pressure on push button 14 results in the anti-clockwise rotation of the pillar wheel 28 against the action of arm 42 which is caused to slide up the inclined surface 38 of one tooth 36 before then engaging the next. When the pillar wheel 28 has been advanced by one tooth 36 further rotation is prevented by the engagement of the pawl 10 with the substantially planar region 24 of the reference surface 12. The push button 14 is then released and the pawl 10 returned to its starting position by the action of the arcuate spring portion 18 which, when the push button is fully depressed, is received in the arcuate cut away region 26. The engagement of the arcuate spring portion 18 with a lip of the cut away region 26 causes the heel portion 20 to slide up the inclined ramp 22 thereby again imparting to the pawl 10 a component of movement transverse to the direction of the applied force and sufficient to withdraw the forwardly projecting portion 16 from engagement between the teeth 36 of the pillar wheel 28.

As the pillar wheel 28 is rotated by the pawl 10 one of the castellations 48 provided on its upper surface 46 is brought into engagement with the first cam surface 140 of the body portion 126. The engagement of the cam surface 140 with the outer arcuate surface 52 the castellation 48 causes the body portion 126 to rotate clockwise about shaft 124 not withstanding the resistance provided by the engagement of the second cam surface 142 with the angled surface portion 170 of the locking spring 144.As the body portion 126 rotates the region of engagement between the second cam surface 142 and the angled surface portion 170 moves along the first inclined surface 172 past the angle and on to the second inclined surface 174 to the position shown in Figure 2 so that when the pillar wheel 28 has stopped rotating the body portion 126 is prevented from returning to its original position by the action of the locking spring 144.

The rotation of the body portion 126 also causes the rotation of the upper and lower zeroing levers 118 and 120 so that their respective planar surfaces 136 and 138 are no longer in engagement with the arcuate surfaces 76 and 88 of cams 70 and 82. At the same time the rotation of the laterally projecting tail 146 allows the tab portion 154, biased by the second blade spring 162, to pivot the bi-concave lever 150 about its axis 152 and so enable the intermediate toothed wheel 164 to enter into intermeshing engagement with toothed wheel 68.

While bringing one of the castellations 48 into engagement with the first cam surface 140 of the body portion 126, the rotation of the pillar wheel 28 also causes the boss 114 carried by the touch-piece 110 to engage one of the indentations 60 provided on its under surface 58. The engagement of the boss 114 in this way decreases the downward pressure applied to the clutch 98 by the touch piece 110 and enables the residual pressure to be overcome by the leaf spring 106. As a result the clutch 98 is urged upwardly away from the abutment 108 to sandwich the seconds driving wheel 94 between the top plate 100 and the first disk plate 80.In this position the friction between the seconds driving wheel 94 and the top plate 100 is sufficient to cause the clutch 98 to begin to rotate with the seconds driving wheel 94 and this, combined with the friction between the leaf spring 106 and the abutment 108, not to mention the friction between the seconds driving wheel 94 and the first disk plate 80, is sufficient to also begin to rotate the outer of the two concentric shafts 64. As a result the seconds elapsed indicator 78 carried by the outer shaft 64 is caused to rotate with the same angular velocity as the seconds driving wheel 94.

The second disk plate 90 which is also carried by the outer shaft 64 is likewise caused to rotate with the seconds driving wheel 94. The radially projecting finger 92 provided on the second disk plate 90 is similarly rotated and once in every complete revolution is brought into engagement with the intermediate toothed wheel 164. This engagement of the radially projecting finger 92 causes the advancement of the intermediate toothed wheel 164 by one tooth in every complete revolution of the second disk plate 90.Since the intermediate toothed wheel 164 is now in intermeshing engagement with the toothed wheel 68, the advancement of the intermediate toothed wheel 164 gives rise to a corresponding advancement of the toothed wheel 68 not withstanding the action of the jump lever 122 which, because of the shape of the angled portion 128, does not engage the toothed wheel 68 sufficiently to prevent such rotation. The rotation of the toothed wheel 68 in turn causes the rotation of the inner of the two concentric shafts 62 and with it the rotation of the minutes elapsed indicator 66. Thus the minutes elapsed indicator 66 is caused to rotate through an arc whose length is in part defined by the gear ratio between the intermediate toothed wheel 164 and the toothed wheel 68 once in every complete revolution of the seconds elapsed indicator 78.The total length of time that has elapsed since depressing push button 14 maybe read in minutes and seconds off a suitable scale (not shown) located adjacent the minutes and seconds elapsed indicators 66 and 78.

To stop the chronograph mechanism push button 14 is again depressed causing the pawl 10 to advance the pillar wheel 28 by one tooth in the manner previously described. The rotation of the pillar wheel 28 causes the advancement of the castellation 48 previously engaged by the first cam surface 140 of the body portion 126. As a result the first cam surface 140 is now disposed adjacent a space between that castellation and the next but is prevented from falling back by the engagement of the second cam surface 142 of the body portion 126 with the second inclined surface 174 of the angled surface portion 170 of the locking spring 144. Thus despite the rotation of the pillar wheel 28 the lever mechanism 116 remains stationary.

The advancement of the pillar wheel 28 however does cause the boss 114 carried by the touch-piece 110 to disengage the indentation 60 in which it was previously receieved and instead to engage a point on the under surface 58 of the pillar wheel between that indentation and the next. This new engagement increases the downward pressure applied to the clutch 98 by the touch-piece 110 and compresses the leaf spring 106 thereby disengaging the clutch from the seconds driving wheel 94. Without the engagement of the clutch 98 the outer shaft 64 is deprived of its rotational drive and the seconds elapsed indicator 78 ceases to rotate. With the second disk plate 90 stationary the inner shaft 62 is also deprived of its rotational drive and the minutes elapsed indicator 66 similarly ceases to rotate.

When the chronograph mechanism is stopped the minutes and seconds elapsed indicators 66 and 78 are prevented from idly rotating about their respective shafts 62 and 64 in order to facilitate the reading of the total length of time that has elapsed since first depressing the push button 14. In the case of the minutes elapsed indicator 66 this is achieved by the engagement of the angled portion 128 of the jump lever 122 between the teeth of the toothed wheel 68 while in the case of the seconds elapsed indicator 78 this is achieved by the friction that exists between the leaf spring 106 and the abutment 108.

To restart the chronograph mechanism push button 14 is depressed to once more advance the pillar wheel 28 in the manner previously described.

The rotation of the pillar wheel 28 causes the next castellation 48 to be brought into engagement with the first cam surface 140 of the body portion 126.

However, because the second cam surface 142 is still in engagement with the second inclined surface 174 of the angled surface portion 170, the engagement of the first cam surface 140 with the outer arcuate surface 52 of the next castellation 48 does not cause the lever mechanism 116 to rotate. The advancement of the pillar wheel 28 however does cause the boss 114 carried by the touch-piece 110 to engage the next indentation 60 provided on its under surface 58. As has been previously described, the engagement of the boss 114 in this way decreases the downward pressure applied to the clutch 98 by the touch-piece 110 and allows the clutch to engage the seconds driving wheel 94 under the action of the leaf spring 106.As a result the rotational movement of the seconds driving wheel 94 is coupled to the two concentric shafts 62 and 64 to drive the minutes and seconds elapsed indicators 66 and 78.

The chronograph mechanism may be started and stopped as many times as is required.

In order to reset the chronograph mechanism and return the minutes and seconds elapsed indicators 66 and 78 to zero the mechanism is first stopped as previously described. The second push button 178 is then depressed bringing the head piece 174 into engagement with the laterally projecting tail 146 of the body portion 126. Continued downward pressure on the second push button 178 causes the tail 146, and consequently also the body portion 126, to rotate anti-clockwise about shaft 124 not withstanding the resistance provided by the engagement of the second cam surface 142 with the angled surface portion 170 of the locking spring 144. As a result the tail 146 is brought into engagement with the arcuate surface 148 of the bi-concave lever 150 causing the lever to pivot about its axis 152.As it does so the tab portion 154 is sandwiched between the other limb of the lever 156 and the concave surface 158 of the locking spring 144 causing the intermediate toothed wheel 164 to be withdrawn from engagement with the toothed wheel 68 against the action of the second blade spring 162. Meanwhile as the body portion 126 rotates the first cam surface 140 pivots into the space between two adjacent castellations 48 while the region of engagement between the second cam surface 142 and the angled surface portion 170 moves back along the second inclined surface 174 past the angle and on to the first inclined surface 172 to the position shown in Figure 1.

The rotation of the body portion 126 also causes the rotation of the upper and lower zeroing levers 118 and 120. As a result the upper zeroing lever 118 is brought into engagement with the first cam 70 in such a way that the planar surface 136 abuts one or other of the oppositely directed cam surfaces 72 or 74. Which of the oppositely directed cam surfaces 72 or 74 is engaged by the planar surface 136 will depend on the angle through which the first cam 70 has been rotated but in either event continued rotation of the zeroing lever 118 causes the cam 70 to rotate until the planar surface 136 engages the arcuate surface 76. Thereafter with the upper zeroing lever 118 in the position shown in Figure 1 no further rotation of the zeroing lever or the cam is possible.The sense in which the cam 70 is rotated by the zeroing lever 118 is determined by the identity of the cam surface 72 or 74 engaged by the planar surface 136 and in either event results in a corresponding rotation of the inner of the two concentric shafts 62, and with it the minutes elapsed indicator 66, despite the engagement of the jump lever 122 with the toothed wheel 68. Thus providing the minutes elapsed indicator 66 is mounted on the inner shaft 62 in such a way that it registers zero when the planar surface 136 is in engagement with the arcuate surface 76 the indicator may be realiably and accurately zeroed when required.

Similarly, upon rotating the body portion 126 the lower zeroing lever 120 is brought into engagement with the second cam 82 so that the planar surface 138 abuts one or other of the oppositely directed cam surfaces 84 or 86. As with the first cam 70, the identity of the cam surface engaged by the planar surface 138 will depend on the angle through which the second cam 82 has been rotated but, again, in either event continued rotation of the lower zeroing lever 120 causes the cam 82 to rotate until the planar surface 138 engages the arcuate surface 88 whereafter no further rotation of the zeroing lever or the cam is possible.The sense in which the cam 82 is rotated by the lower zeroing lever 120 is, as before, determined by the identity of the cam surface 84 or 86 engaged by the planar surface 138 but in either event results in a corresponding rotation of the outer of the two concentric shafts 64 despite the friction that exists between the leaf spring 106 and the abutment 108.

The seconds elapsed indicator 78 rotates with the outer shaft 64 and if mounted appropriately may be made to register zero when the planar surface 138 is in engagement with the arcuate surface 88. In this way the seconds elapsed indicator 78 may, like the minutes elapsed indicator 66, be realiably and accurately zeroed when required.

Having zeroed the minutes and seconds elapsed indicators 66 and 78 push button 178 is released to return to its starting position under the action of spring 44.

It will be apparent to those skilled in the art that whilst the inner and outer shafts 62 and 64 have been described as being concentric this need not necessarily be the case. Instead the two shafts may be displaced from each other in order to provide a chronograph having separate scales for the elapse of both minutes and seconds. Likewise it will be apparent that neither the minutes elapsed indicator 66 or the seconds elapsed indicator 78 need necessarily be mounted coaxially with the seconds driving wheel 94.

It will also be apparent to those skilled in the art that by providing a mechanism capable of being accommodated between the front and back plates of the chronograph the overall thickness of the movement maybe reduced. Furthermore, having accommodated the mechanism in this way it will be apparent that the seconds elapsed indicator may be mounted for rotation about an axis displaced from those of the conventional minute and hour hand thereby enabling a still greater reduction in the thickness of the movement.

Claims (12)

1. A chronograph comprising a rotatable seconds elapsed indicator, a driving member which in use is continuously rotated, a clutch member mounted for rotation about an axis coaxial with the driving member and actuating means to cause axial movement of the clutch member and effect direct or indirect engagement between the driving member and the seconds elapsed indicator.
2. A chronograph in accordance with Claim 1, wherein the seconds elapsed indicator is mounted for rotation about an axis coaxial with the driving member.
3. A chronograph is accordance with Claim 1 or Claim 2, wherein means are provided to bias the clutch member towards a position in which the driving member is in direct or indirect engagement with the seconds elapsed indicator and the actuating means serves to urge the clutch member against the said biasing means.
4. A chronograph having at least one hand to indicate the time and a seconds elapsed indicator mounted for rotation about an axis displaced from that of the said at least one hand.
5. A chronograph in accordance with claim 4, wherein the chronograph has a top plate and a bottom plate and the chronograph mechanism is accommodated between the two.
6. A chronograph substantially as herein described with reference to the accompanying drawings.
7. A device for advancing a wheel of a time-piece comprising a pawl member that when moved in a first direction engages and rotates the wheel, the pawl member being constrained to move in a direction transverse to but having a component in the said first direction.
8. A device in accordance with claim 7, wherein the pawl member is in sliding engagement with a reference surface which is so adapted that on the application of a force to the pawl member the engagement with the reference surface imparts to the pawl member a component of movement transverse to the applied force and sufficient to cause the pawl member to engage and rotate the wheel.
9. A device in accordance with claim 8, wherein the reference surface comprises an inclined ramp contiguous with a substantially planar region so that having moved down the ramp the pawl member is prevented from further movement in the direction of the applied force by engagement with the substantially planar region thereby limiting the angular displacement of the wheel.
10. A device in accordance with claim 8 or claim 9, wherein the pawl member is provided with a resilient means that projects from a surface of the pawl member opposed to the reference surface and which is adapted to return the pawl member to its starting position upon release of the applied force.
11. A device in accordance with Claim 10, when dependant on claim 9, wherein the reference surface is provided with a cutaway region to accommodate the resilient means when the pawl member is in engagement with the substantially planar region.
12. A device for advancing a wheel of a time-piece substantially as herein described with reference to Figure 3 of the accompanying drawings.
GB9209925A 1992-05-08 1992-05-08 Improvements relating to chronographs Withdrawn GB9209925D0 (en)

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Application Number Priority Date Filing Date Title
GB9209925A GB9209925D0 (en) 1992-05-08 1992-05-08 Improvements relating to chronographs

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Application Number Priority Date Filing Date Title
GB9209925A GB9209925D0 (en) 1992-05-08 1992-05-08 Improvements relating to chronographs

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GB9209925D0 GB9209925D0 (en) 1992-06-24
GB2266791A true true GB2266791A (en) 1993-11-10

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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1296205A1 (en) * 2001-09-24 2003-03-26 Girard-Perregaux S.A. Chronograph mechanism
EP2410388A1 (en) * 2010-07-21 2012-01-25 Blancpain S.A. Time piece with double display
US20130100781A1 (en) * 2010-04-23 2013-04-25 François-Régis Richard Chronograph mechanism, clockwork movement and timepiece comprising such a mechanism

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1403127A (en) * 1972-03-15 1975-08-13 Ebauches Sa Mechanism for coupling and braking a rotatable member of a time piece or of a small mechanism
GB1410208A (en) * 1971-12-13 1975-10-15 Citizen Watch Co Ltd Time-setter for an electronic timepiece
GB1467684A (en) * 1973-07-10 1977-03-16 Suisse Pour Lindustrie Horloge Clockwork movement comprising a gear-train with a friction clutch therein
GB1467683A (en) * 1973-07-10 1977-03-16 Suisse Pour Lindustrie Horloge Chronograph movement

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1410208A (en) * 1971-12-13 1975-10-15 Citizen Watch Co Ltd Time-setter for an electronic timepiece
GB1403127A (en) * 1972-03-15 1975-08-13 Ebauches Sa Mechanism for coupling and braking a rotatable member of a time piece or of a small mechanism
GB1467684A (en) * 1973-07-10 1977-03-16 Suisse Pour Lindustrie Horloge Clockwork movement comprising a gear-train with a friction clutch therein
GB1467683A (en) * 1973-07-10 1977-03-16 Suisse Pour Lindustrie Horloge Chronograph movement

Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1296205A1 (en) * 2001-09-24 2003-03-26 Girard-Perregaux S.A. Chronograph mechanism
WO2003027778A2 (en) * 2001-09-24 2003-04-03 Girard-Perregaux Sa Chronograph mechanism
WO2003027778A3 (en) * 2001-09-24 2003-07-10 Girard Perregaux Sa Chronograph mechanism
US6926438B2 (en) 2001-09-24 2005-08-09 Girard-Perregaux Sa Chronograph mechanism
US20130100781A1 (en) * 2010-04-23 2013-04-25 François-Régis Richard Chronograph mechanism, clockwork movement and timepiece comprising such a mechanism
EP2410388A1 (en) * 2010-07-21 2012-01-25 Blancpain S.A. Time piece with double display
WO2012010392A2 (en) 2010-07-21 2012-01-26 Blancpain Sa Dual display timepiece
CN102346426A (en) * 2010-07-21 2012-02-08 布朗潘有限公司 Time piece with double display
WO2012010392A3 (en) * 2010-07-21 2012-04-26 Blancpain Sa Dual display timepiece
CN102346426B (en) 2010-07-21 2013-08-14 布朗潘有限公司 Time piece with double display
KR101375452B1 (en) 2010-07-21 2014-03-17 불랑패인쏘시에떼아노님 Dual display timepiece
US8848488B2 (en) 2010-07-21 2014-09-30 Blancpain S.A. Dual display timepiece

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