US3817110A

US3817110A - Device for transforming oscillating movement into rotary movement

Info

Publication number: US3817110A
Application number: US00306405A
Authority: US
Inventors: C Challandes
Original assignee: Montres Rolex SA
Current assignee: Rolex SA
Priority date: 1971-11-15
Filing date: 1972-11-14
Publication date: 1974-06-18
Anticipated expiration: 1991-06-18
Also published as: DE2255982A1; FR2161607A5; CH533785A; JPS4858251A

Abstract

A device for transforming oscillating movement into rotary movement includes a flexible blade fixed at one end and carrying a pawl in driving engagement with a ratchet wheel at its other free end. Between its ends, the blade has a bent or curved portion and a bearing piece acts on the blade between its bent portion and its fixed end. This bearing piece transforms the oscillating movement of a driving member into an unilateral pressure on the blade, which flexes the blade and causes the pawl to drive the ratchet wheel. To prevent reversal of the ratchet wheel, a retaining pawl can be provided; alternatively two bent flexible blades each carrying a driving pawl may be driven in phase opposition.

Description

United States Patent Challandes June 18, 1974 DEVICE FOR TRANSFORMING OSCILLATING MOVEMENT INTO ROTARY MOVEMENT [75] Inventor: Claude Challandes,Sonceboz, Switzerland [73] Assignees: Montres Rolex S.A., Geneva; V

Manufacture des Rolex S.A., Bienne; Societe anonyme de la fabrique dhorlogerie Le Coultre & Cie, Le Sentier, all of, Switzerland 22 Filed: Nov. 14,1972

[21] Appl. No: 306,405

[30] Foreign Application Priority Data Nov. 15, 1971 Switzerland 16551/71 [52] US. Cl. 74/142, 74/128 [51] Int. Cl. Fl6h-27/02 [58] Field of Search 74/142, 128, 575, 577

[56] References Cited UNlTED STATES PATENTS 1,632,405 6/1927 Harrison 74/143 2,868,026 1/1959 Finehout et al 74/142 3,204,133 8/1965 Tshudin 74/142 3,489,024 l/1970 Ramsetter 74/142 5 7] ABSTRACT A device for transforming oscillating movement into rotary movement includes a flexible blade fixed at one end and carrying a pawl in driving engagement with a ratchet wheel at its other free end. Between its ends, the blade has a bent or curved portion and a bearing piece acts on the blade between its bent portion and its fixed end. This bearing piece transforms the oscillating movement of a driving member into an unilateral pressure on the blade, which flexes the blade and causes the pawl to drive the ratchet wheel. To prevent reversal of the ratchet wheel, a retaining pawl can be provided; alternatively two bent flexible blades each carrying a driving pawl may be driven in phase opposi tion.

4 Claims, 12 Drawing Figures PATENTEDJun 18 m4 sum u or 5 Fig. 1a

PATENTI'IBJ sum 5 er 5,

MOVEMENT OF 757' PAWL MOVEMENT 0F ZNOIPAWL Flg.11

DEVICE FOR TRANSFORMING OSCILLATING MOVEMENT INTO ROTARY MOVEMENT The invention relates to devices for transforming oscillating movement into rotary movement and is particularly concerned with devices for transforming the oscillating movement of a driving member into a rotary movement of a toothed wheel by means of at least one driving pawl on the end of a blade.

Swiss Pat. No. 497,725 (Straumann) describes (with reference to FIG. 1 of its drawings) a device for transforming a rotary movement into a slower rotary movement by means of a bent blade. The rotary movement to be transformed is transmitted to the blade by means of an eccentric disposed in the proximity of the bent part of the blade. The eccentric drives the blade with an oscillating movement causing a toothed wheel to be turned around. Turning of the wheel is thus caused by the movement produced by the eccentric and transmitted to the toothed wheel via the blade.

An object of the invention is to provide a device for transforming an oscillating movement into a rotary movement by means of a pawl-carrying flexible blade by using the property of resilient flexibility of the blade to drive a toothed wheel.

The device according to the invention is characterised in that this blade includes a bent portion, the end of the blade opposite to the pawl-carrying end being fixed. The driving member transmits its movement via a bearing part exerting an unilateral pressure on the blade between the support and the bent portion to produce flexion of the blade.

The term bent portion is herein used to designate not only abrupt elbow-like bent portions, but also curved or bowed portions.

Three embodiments of the invention will now be described, by way of example, with reference to the accompanying schematic drawings, in which:

FIG. 1 shows a bent blade for transmitting the oscillating movement of a resonator to a mobile or driving pawl;

FIGS. 2 and 3 are explanatory graphs illustrating the operation of the blade of FIG. 1;

FIG. 4 is a plan view of a first embodiment of device according to the invention, this device including a pawl-carrying blade similar to that of FIG. 1;

FIG. 5 is an enlarged scale view showing several teeth of the ratchet wheel of FIG. 4;

FIG. 6 is a graph showing the operative driving range of the single driving pawl of the device of FIG. 4;

FIG. 7 is a plan view of a second embodiment of device according to the invention for transforming an oscillating movement of relatively large amplitude into a rotary movement;

FIG. 8 is a graph explaining the operation of the device of FIG. 7;

FIG. 9 is a view of a detail showing means for limiting the lateral movement of a pawl;

FIG. 10 is a plan view of a third embodiment of device according to the invention for transforming the movement in phase opposition of two arms of a resonator into a rotary movement;

FIG. 1 1 is an explanatory graph for the device of FIG. 10; and

FIG. 12 shows a mechanism for setting the phase of the pawls of the device of FIG. l0.

The flexible blade 1 shown in FIG. 1 is bent with a certain angle a and one of its ends is solidly secured to a fixed support 2 by being set or embedded therein. Its other free end B carries a pawl which moves over a surface 3 corresponding to the tangent to a toothed wheel at the point of contact of the pawl therewith. The movement from A to A of a pin 4 acting on the blade 1 causes a displacement D of the end E of the blade to E. Displacement of the blade from A to A takes place over a distance f called the deflection, and the blade is divided into three segments of length l l and 1 as shown in FIG. 1.

The displacement D of the end of the blade depends not only on the deflexion f but also upon the parameters a, l l and 1 For given lengths l l and 1 a family of curves of the displacement D as a function of the deflexion f is obtained for various angles at. These curves are shown in FIG. 2 for three angles or a a The .force F that the pin 4 must exert to produce deflexion f also depends upon the geometrical disposition and upon the rigidity of blade 1.

Referring to FIG. 3, let us now consider a small amplitude sinusoidal movement of the pin 4 superimposed on the means deflexion fin, considered as a tensioning or bracing. A given point-to-point path or amplitude C of the end of pin 4 corresponds to a path or amplitude C of the end E of blade 1, which is a function of the mean tension or deflexion f (curve D (f) of FIG. 3). The ratio C /C is the slope of the tangent T of curve a in FIG. 3 at the working point. By suitably selecting the values of 01, 1 ,1 and fm, it is thus possible to pro duce an amplification or a reduction (attenuation) of the amplitude of the movement.

This principle is applied for transforming the vibratory movement of a resonator into a rotary movement. A device provided for this purpose is shown in FIG. 4 and comprises a bent blade 5 similar to the blade of FIG. 1. One of the ends of blade 5 is firmly secured at 6 to a fixed support by being set or embedded therein, and the other free end carries a pawl 12 bearing against a toothed wheel 7 the very fine teeth of which are not shown in FIG. 4. A pin 8 connected to an arm 9 of a resonator bears perpendicularly against the blade 5 and transmits to pawl 12 the vibratory movement of the resonator arm 9, as indicated by the double headed arrow. The pin 8 acts on the substantially rectilinear part of blade 5 located between its point of fixation and the bent part, preferably near to the bent part. An end 11 of a substantially rectilinear second flexible blade 10 is finnly secured to the fixed support, and its other free end carries a retaining pawl 13 which also contacts the teeth of wheel 7. The two pawls are in phase when at rest the distance separating them is equal to (n MP, where n is a whole number and P is the pitch of the teeth of wheel 7 (FIG. 5). The resonator drives the ratchet wheel 7 by means of pawl 12.

It is clear that blade 5 could, instead of having a sharp bend as shown in FIG. 4, have a smooth curvature or bowed part near its pawl-carrying end. In such a variation, not shown, the blade has a straight part adjacent its fixed end followed by a curved part extending from the point of action of pin 8 to the free end carrying pawl 12. The explanations given in relation to FIGS. 2 and 3 remain valable for a curved blade, and in this case the angle a is the angle formed between a tangent to the free end of the blade and a perpendicular to the straight part of the blade. Also the blade 5 could, in a limiting case, be curved or bowed from end to end, for example in the shape of an arc of a circle.

Moreover, the blade could be secured to the support by means of a pivot.

The operating conditions for the pawl-and-ratchet drive are shown in FIG. 6. The pawl 12 moves with a periodic movement represented by the sinusoidal curve D(t) centred about the mean value D,, and whose point-to-point travel or amplitude is C The conditions to be fulfilled for the pawl 12 to drive wheel 7 by only one tooth per period are defined by the extreme positions of the pawl. In its forward movement (considering the direction of rotation of wheel 7 indicated by the arrow in FIG. 4), the pawl 12 reaches an extreme position D, k C It drives the wheel and the fixed or retaining pawl 13 jumps from one tooth to the following at the ordinate Da If pawl 12 moves further, the wheel 7 would be rotated by a greater amount and, at D113, the pawl 13 would jump a second tooth. The extreme forward position of the pawl 12 must thus be comprised between Da and D11 preferably in the neighborhood of the mean ordinate Da In its rearward movement, pawl 12 drives the wheel 7 in the reverse direction until one of the teeth of wheel 7 comes to abut against pawl 13. Then, the wheel 7 is fixed and the driving pawl 12 slips over a tooth until it jumps to the following tooth at ordinate Dr If pawl 12 continues to move back, it will jump over a second tooth at Dr;,. The extreme rearward position of pawl 12 must thus be comprised between Dr, and Dr;,, preferably near to the mean ordinate Dr Consequently, the best operation corresponds to a mean position D of pawl 12 coinciding with the ordinate D centred in relation to Da and Dr and which will be designated by the term zero phase, and with the path C of pawl 12 equal to twice the pitch P of the teeth of wheel 7. In these conditions, the greatest possible safety margin is provided concerning possible deviations in the phase D,, or the path C For example, if the amplitude is correct, the phase may vary by nearly P without causing an irregularity in the drive. If the phase is correct, the path C may vary from a minimum slightly above P to a maximum nearly up to 3 P. It is clear that by staggering or displacing all of these ordinates D by a phase corresponding to the pitch P or a multiple thereof, new equally valid limiting values will be obtained (see the right hand part of FIG. 6).

These considerations show the importance of ensuring that the driving pawl 12 has a well determined and constant phase and amplitude. An aim of the invention is to ensure that these conditions are fulfilled, even if the movement of the driving member (resonator or pallet) is less precise and subject to unwanted variations, for example as a result of shocks.

With use of a bent blade, several cases arise.

1. One Driving Pawl; One Fixed Pawl l.l Large Tensioning, Small Amplitude In the graph of FIG. 3, the short portion of the curve about the operating point can be approximated to a straight line. The transformation of movement between the driving pin and the end of the driving pawl is thus linear and corresponds to a constant ratio C /C This ratio can be modified by varying the mean tensioning or deflexion f Appropriate choice of the blade parameters (for the device of FIG. 4) enables the resonator amplitude at a given point to be adapted to the pitch of wheel 7, whatever be the point of fixation of the driving pin 8. Great freedom in the construction is thus available since the resonator amplitude and the pitch P are independent.

Also, the pressure exerted by the pawl-carrying blade 5 on wheel 7 varies during its movement. At the end of its path, pawl 12 passes from a forward to a rearward movement whilst exerting a high pressure on the wheel 7, and therefore tends to drive the wheel rearwardly, which is desirable for correct operation. When the rearward movement of wheel 7 is stopped by pawl 13, pawl 12 continues to move rearwardly whilst sliding over a tooth, then jumping to the next tooth. This sliding involves a loss of energy. It is thus advantageous that the end of the rearward movement takes place at reduced pressure. The variation of the pressure exerted by pawl 12 thus favors a low power consumption.

The arrangement of FIG. 4 provides transmission of the movement in the desired direction, as indicated by the double headed arrow. On the contrary, any movement of the resonator in the two other directions (hori zontal lateral and perpendicular in relation to the drawing) produces a simple sliding of pin 8 on blade 5, without transmission of this movement to pawl 12. Such unwanted movements thus cause neither a variation in the phase of the pawls, nor a variation in the tensioning or deflexion of blade 5, nor a lateral displacement liable to move pawl 12 out of the plane of wheel 7. This noncoupling in two directions is an inherent property of the device according to the invention and contributes to its safety of operation by rendering it insensitive to various effects such as shocks and expansions. Moreover, it enables a relaxation of certain manufacturing tolerances and facilitates mounting.

1.2 Zero Tensioning, Large Amplitude This case (described with reference to FIG. 7) is applicable to a wheel 7 having teeth of a sufficiently large pitch to enable advantage to be drawn from the nonlinearity of the curves of FIG. 2. The movement of an oscillating member 31 is transmitted to a blade 5 carrying a driving pawl 12 by means of a bent pin 8 which, at rest, applies against blade 5 without deflecting it. In this example, the angle of bending of blade 5 is less pronounced than for that of FIG. 4. In its forward movement, the pin 8 moves pawl 12 forwardly at first rapidly then progressively slower. During return, the movement takes place in the opposite direction, but as soon as the pin 8 passes its rest position it moves away from blade 5 which stops all transmission of movement. To avoid the pawl 12 from moving out of engagement with wheel 7 during this phase, blade 5 may have a sufficient tension by a suitable inclination at its point of securing 6. It is also possible, as shown, to provide a pin 32 fixed on the support, this pin limiting movement of blade 5 and precisely determining the position at which pin 8 moves away from blade 5. FIG. 8 shows a typical non-linear characteristic D (f) of this device, as well as the positions Da,, Da,, Da;,, Dr Dr Dr of the pawl as discussed in connection with FIG. 6. To these positions correspond deflexions on a non-linear scale, and even certain ordinates such as fa fr and fr are inaccessible. Consequently, there is a considerable increase in the zones of correct opera tion. It suffices, in practice, to guarantee that during its movement pin 8 advances beyond a first limit fa then moves back beyond a second limit fr By way of example, three periodic movements of the pin are shown at 41, 42 and 43. The corresponding movements of pawl 12 are indicated by

curves

51, 52 and 53. Curve 41 corresponds to a movement of minimum amplitude compatible with a correct counting operation (regular operation). Curve 42 corresponds to a mean amplitude, and curve 43 to a large amplitude. It can be seen that the extreme positions of the pawl given by

curves

51, 52, 53 vary but to a lesser degree. The device thus enables much larger tolerances in the mean phase and in the path (amplitude) of the driving member 31. It is also more resitant to shocks.

Although the devices of FIGS. 4 and 7 prevent any transmission to the pawl-carrying blade 5 of a movement of pin 8 perpendicular to the plane of these Figures, it is not impossible that a violent shock in this direction would directly act on either or both of pawls l2 and 13 and make them move out of the plane of wheel 7. FIG. 9 shows a device for avoiding this, in which a pawl-forming stone 20 supported by a blade 21 compelled to remain in the plane of a ratchet wheel 22 by means of two limiting

pieces

23 and 24 the facing surfaces of which are spaced apart on either side of the plane of wheel 22 and in the vicinity of the pawlforming stone 20.

2. Two Mobile Pawls In the embodiment of FIG. 10, two

bent blades

25 and 26 respectively carry two driving

pawls

27 and 28 both in driving engagement with a toothed wheel 14. The

blades

25 and 26 are respectively firmly supported at and 16 on a fixed support 17.

Pins

18 and 19 each connected to or mounted on an arm of a resonator (not shown) come to bear against the

blades

25, 26 respectively in the proximity of the bent portions thereof.

The two arms of the resonator (not shown) oscillate is phase opposition and each

18, 19 drives its

respective pawl

27, 28 in the same manner as in the device of FIG. 4 with one bent blade. The device of FIG. 10 is advantageous from the point of view of power consumption since the path of the pawls is halved. Moreover, any phase error caused by a simultaneous movement of

pins

18 and 19 in the same direction, as a result of a shock for example, is practically totally excluded.

Curves

61 and 62 of FIG. 11 illustrate the movements of the two

pins

18, 19 during normal operation at a working point T and with a path or amplitude C Suppose that as a result of a shock, the two arms of the resonator are both displaced by an amount A in the same direction. The result of this is to displace the working point from T to T. If the displacement A is the same for the two blades, the resulting dephasing of their pawls is zero. The working point T is chosen so that the slope C /C varies only slightly upon a displacement of the working point from T to T. Consequently, the path or amplitude C of the pawls during this displacement is close to the initial path C and the counting operation (i.e., regular running) is not disturbed. Phase Adjustment In all of the above described arrangements, adjustment of the phase between the two pawls so that their separation corresponds to (n k) P is indispensable to obtain the indicated characteristics.

In conventional pawl and ratchet systems. the pawl is generally fixed on an element having a center of pivoting coinciding with the center of the ratchet wheel, which enables modification of the phase of the pawls without altering the pressure with which they engage the wheel.

This principle is not applicable to the device according to the invention, since displacement of the pawls about the wheel would modify the tension of the driving pin against the pawl-carrying blade.

An arrangement which enables modification of the phase of the pawls without altering the pressure on the wheel and on the pin is shown in FIG. 12. In this phase adjusting mechanism, the blade 5 carrying an adjust able pawl 13 is fixed at 6 onto a resilient blade 71 firmly fixed at one end at 73 and bearing against a wedgelike member 72. A screw 74 is adapted to bear against the other free end of blade 71 to enable modification of the bowing thereof between its fixed end and member 72. The point 6 of securing blade 5 is preferably where the deflexion of blade 71 is maximum dy/dx 0). Because of this, when the adjusting screw 74 flexes blade 71, the pawl-carrying blade 5 moves in the direction of arrow F, without changing its inclination relation to the point of securing. This movement enables adjustment of the phase of the pawls without alteration of the pressure, since movement of blade 5 during adjustment takes place (a) in the longitudinal direction of the substan tially rectilinear part of blade 5 between point 6 and the bent portion, i.e., perpendicular to the direction of movement of the intermediary driving piece, and (b) at least substantially parallel to the tangent to wheel 7 at the point of contact of pawl 13. Also, by suitably choosing the distance d in relation to the pitch of screw 74, an adequate sensitivity for carrying out adjustment will be obtained. An important advantage of this device is that adjustment of the phase can take place during operation of the resonator.

Advantages The advantages in relation to conventional devices of the described devices with one bent blade are as follows:

Since the resonator and the bent blade are noncoupled, there is an improvement in the resistance to shocks in the two directions perpendicular to movement of the driving pin.

Increase in the range of operation by provision of means for non-linearly transforming movement be tween the resonator and and the ratchet wheel, the results of which are reduction of the sensitivity to shocks in the direction of movement of the driving pin and increase in the amplitude and phase tolerances.

Possibility of constructing a pawl and ratchet unit independent of the resonator.

The danger of dephasing due to play or relaxation (slackening) effects is reduced, since the two pawls are secured on the same support.

Since forward movement of the wheel is produced by an elastic deformation of the pawl-carrying blade, a part of the energy stored in the blade is restituted during rearward movement of the driving pawl.

Possibility of amplification or attenuation of the ratio of amplitude between the resonator and the pawl for a given point of securing the driving pin. This offers a great freedom in construction.

Ease of mounting, and reduction of the risks inherent during repair since the pawls are not secured to the resonator.

The described device with two bent blades has the following additional advantages:

"Complete elimination of risks due to an identical displacement of the two arms of the resonator. Only a movement in phase opposition of the two arms is liable to effect regular running.

If shocks (angular and linear) cause no movement in phase opposition of the resonator arms they do not effect regular running.

Reduction of the power consumption.

What is claimed is:

1. Device for transforming an oscillating movement of a resonator driving member comprising two arms oscillating in phase opposition into a rotary movement of a toothed wheel, comprising two flexible blades each having a first end fixed to a support and a free second end, each blade including a bent portion intermediate of said first and second ends and having a pawl at its free second end in driving engagement with said toothed wheel, said blades each cooperating with a respective bearing piece formed by a pin on a respective one of said two arms between said fixed first end and said bent portion, said pins forming means for exerting an unilateral pressure on each blade to flex said blades and drive said pawls in phase opposition.

2. Device according to claim 1, comprising means for adjusting the distance between the points at which said first ends of said blades are fixed to said support.

3. Device according to claim 2, in which said adjusting means include a resilient elongate member having one end fixed to said support and another free end, and screw means for resiliently displacing said free end of the member, the first end of one of said blades being fixed to said member at a point such that when said free end of said member is displaced, said one blade is moved without rotation thereof along the direction of a rectilinear part of said one blade between the first end and the bent portion thereof.

4. Device for transforming an oscillating movement of a driving member into a rotary movement of a toothed wheel, comprising at least one flexible blade having a first end fixed to a support and a free second end, said blade including a bent portion intermediate of said first and second ends, a pawl at said free second end of the blade, said pawl drivable engaging with said toothed wheel and disposed between a pair of facing surfaces spaced apart on either side of the plane of said toothed wheel, said surfaces forming means for limiting movement of said pawl out of said plane of said toothed wheel, and a bearing piece acted on by the driving member and acting on the blade between said fixed first end and said bent portion, said bearing piece forming means for transforming oscillating movement of the driving member into an unilateral pressure on the blade to flex the blade.