Timer

A timer advantageously in the form of a wristwatch and is combined with the time indicating function of the watch. The timer comprises a setting device enabling an accumulator to be loaded through the medium of a position transducer. The movement of the setting device being a stepwise one, each of its shifts enables a pulse to be generating which corresponds to a number of reference periods supplied by a time base. The accumulator is counted down by the time base and, when the accumulator is empty, a warning signal generating device is triggered.

FIELD OF THE INVENTION 
The present invention relates to clock devices, also called timers, 
enabling the production of a warning signal to be caused after the expiry 
of an interval of time which can be set in advance. 
DESCRIPTION OF THE PRIOR ART 
Electromechanical timers are used at the present time in many applications, 
among which there may be mentioned kitchen timer which are integrated or 
not in cooking appliances, portable devices enabling the wearer to be 
reminded of a given time (the time of expiry of a parking meter, for 
example) and other similar applications. 
All these timers comprise in general time base establishing a constant 
reference period, a device for setting the interval of time to be 
measured, in which the setting member is provided with a graduation 
calibrated in units of time, a device generating an alarm signal, and 
means for counting the number of reference periods contained in the said 
interval for commanding on its expiry the triggering of the said 
generating device. 
In a known construction of this kind, the means for counting the number of 
reference periods are arranged in the following manner. The time base is a 
quartz resonator which, through the medium of a dividing circuit can 
command a stepping motor of horological type. This motor is coupled to the 
setting member which takes the form of a rotary disc and comprises a 
graduation calibrated in minutes, for example, and cooperating with a 
fixed reference mark. This disc is fast with a cam associated with an 
inverter and provided with a notch which corresponds to the zero position 
of the disc, the inverter being on in one direction for any position other 
than the zero position of the disc. This inverter is electrically 
connected in the circuit of the motor in such manner that as soon as the 
disc leaves the zero position it is set going to bring the disc back. 
Moreover, the generating device is actuated by the inverter in its other 
position when the notch of the disc is in front of it. 
The disadvantage of this type of timer is that its precision is poor, 
because the angular position of the setting member which determines the 
duration of the interval to be measured is not clearly linked to the time 
value that this position is deemed to represent. This is awkward above all 
in the case of short durations, it being understood that the maximum value 
of the scale is generally sixty minutes. If, for example, it is desired 
under these conditions to fix a time of the order of one minute, the 
angular variation in the setting member is only a few degrees, which 
results in a tricky setting operation. Moreover, such timers do not allow 
the fixing of long time intervals, for example of the order of some hours. 
SUMMARY OF THE INVENTION 
The object of the invention is to provide a timer which is without these 
drawbacks. 
The invention therefore relates to a timer of the above-defined type which 
is characteristised in that the setting device is of the stepping type and 
comprises a transducer for the position of the said setting member which 
is capable of generating of pulsed signal, the number of pulses of which 
represents the position of the setting member and, consequently, the 
interval to be measured, and that the counting means comprise an 
accumulator circuit connected, on the one hand, to the transducer to be 
loaded with the number of pulses produced by it and, on the other hand, to 
the time base to count a number of periods of the latter until there is 
coincidence of a value corresponding to this number of pulses, this 
accumulator circuit being also connected to the generating device to 
trigger this when the said value is reached. 
The result of these characteristics is that the setting process is of an 
essentially discontinuous nature, which means that to each step of the 
setting member there always corresponds a predetermined number of 
reference periods. Thus, the capacity for measuring small intervals of 
time with precision depends only on the calibration of the setting device, 
it being possible for each step of the setting member to correspond to any 
length of time whatever chosen through construction. 
Accordingly, the invention enables two different embodiments of the timer 
to be considered, one in which all the steps of the setting device 
correspond to an equal number of reference periods and another in which 
each step can correspond to a different number (low or high) of these 
periods. 
According to a particularly advantageous characteristic of the invention, 
the timer is integrated in a timepiece of the wristwatch type, without 
being connected in spite of this to the mechanism or circuits which ensure 
in this piece indication of the official time, it being possible for the 
time base alone to be common to the two devices. In this application, it 
is advantageous to make the setting member of the timer in the form of a 
date disc capable of being actuated by the stem of the watch, which 
results in a particularly attractive assembly.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
The electromechanical clock device of which several embodiments are about 
to be described hereinafter can be used in an independent manner for 
carrying out a timer function or else be incorporated in a timepiece 
intended to permit the performance of this function and to indicate the 
official time. It is this second version which is chosen in all the 
examples described, but it will be understood that the invention is not 
limited to this sole use of the clockwork mechanism, it being possible for 
this to be carried into effect in an independent manner, whether in the 
form of a piece worn on the wrist or of a table piece, for example. 
This having been established, reference will now be made to FIG. 1 which 
shows a general view of a first embodiment of the invention which concerns 
a wristwatch in which the clock device according to the invention has been 
incorporated. 
Consequently, in FIG. 1 there can be seen the essentials of the mechanical 
parts of the device, that is to say a position transducer 1 which is 
composed essentially of two subassemblies, namely a setting member or 
indicator disc 2 and a switch 3, and is associated with a setting assembly 
4. According to a particular characteristic of the invention, in the 
limits of application to a watch, it is advantageous for the indicator 
disc 2 to replace the date disc and for the setting assembly to be that 
which is usually employed in a watch for setting the date. However, in 
contrast to a date indicating mechanism, the disc 2 is not driven by means 
of the train of the watch, but remains independent therefrom, so that the 
timer function of the assembly can be achieved independently of the 
indication of the official time. 
The switch 3 is connected to a printed circuit 5 provided with an 
integrated circuit 6, the latter comprising not only the customary 
circuits necessary for carrying out the official time function, but also 
those which are required for carrying out the timer function, which part 
of the integrated circuit 6 will be described in detail in the description 
which is about the follow. 
As the setting assembly 4 is designed in exactly the same way as an 
assembly known per se permitting setting or adjustment of the date disc, 
it is not necessary to give a detailed description thereof here. It is 
sufficient to point out that the disc 2 is driven by a setting train 7 
when the stem 8 of the swatch is in its intermediate position, which is 
moreover shown in FIG. 1. Consequently, the stem 8 being in the position 
shown, it is possible to bring the disc into any one of 31 positions, this 
number being chosen to accord with the positions which are usual in a 
timepiece provided with a date indicator. However, it should be understood 
that this number is not restrictive and depends in particular on the 
length and the apportionment of the scale of the disc 2. 
The disc 2 is therefore formed by an annular ring bearing on one of its 
faces information which represents time intervals in minutes distributed 
at intervals of five minutes at a time. In other words, the scale of the 
disc 2 in this case is linear. 
The inner periphery of the disc 2 is provided with a toothing composed of 
teeth 9, on the one hand, and a single notch 10, on the other hand, the 
numbers shown on the disc appearing in succession behind a window 11 
provided in the region of the stem 8 and permitting the user to read the 
length of time at which the timer is set. 
The teeth 9 and the notch 10 cooperate with the switch 3. This comprises a 
plate 12 fixed to the watch mechanism at 13 and provided with a contact 
arm 14 which also constitutes a jumper for positioning the disc 2. This 
contact arm is electrically the movable contact of the switch 3, which 
moreover comprises two fixed contacts 15 and 16 on which the free end of 
the contact arm 14 can come to be applied selectively, it being understood 
that this arm also has an intermediate position in which it is not applied 
against any one of the contacts 15 and 16. It can be seen in FIG. 1 that 
electrical contact is established between the arm 14 and the contact 15 
when the elbow-shaped bearing portion 14a of the arm 14 is lodged in the 
notch 10 of the disc 2. 
FIG. 2 shows another embodiment of the invention according to which, in 
contrast to the embodiment of FIG. 1, there is provided an indicator disc 
2A which does not comprise a linear scale graduated in minutes and 
extending by five minutes at a time, but a non-linear scale, that is to 
say commencing with a fine division in a first zone 2A-1 graduated in one, 
three and five minutes, a second zone 2A-2 graduated in intervals of five 
minutes, and a third zone 2A-3 graduated from quarter of an hour to 
quarter of an hour, up to a total of five hours. 
Of course, the pieces shown in FIGS. 1 and 2 comprise a conventional 
electromechanical clockwork mechanism for driving hands indicating the 
official time, which elements are conventional and therefore do not 
require any detailed description here. 
It is to be noted that FIGS. 1 and 2 show the inoperative position of the 
timer, that is to say the portion 14a of the contact arm 14 is resting in 
the notch 10, by means of which the figure O appears under the window 11. 
It is assumed for the moment that the electronic circuits of the timer ar 
then cut out. 
FIG. 3 shows the situation in which the disc 2A has been shifted by half a 
step from the zero position by turning the stem 8. The portion 14a of the 
contact arm 14 has therefore left the notch 10 to bear on the top of the 
first tooth 9 of the internal toothing of the disc. This brings about the 
shifting of the end of the arm 14 which comes in this way to bear against 
the contact 16 of the switch 3 to give rise to an electric pulse taken 
into account in the electronic circuit by a process which will be 
described hereinafter. After passing from the position of FIG. 3 to that 
of FIG. 4, the disc 2A again performs half a step, so that the portion 14a 
fits between the first and the second tooth 9 of the disc 2. It will be 
seen that under these conditions the end of the arm 14 does not bear 
either on the contact 15 or on the contact 16, which constitutes for the 
electronic circuit a significant item of information which is exploitable 
as such. 
It will be understood, therefore, that by turning the stem 8 in the 
position shown in FIG. 1, the end of the contact arm 14 bears periodically 
on the contact 16 to generate a train of pulses, the number of pulses 
being representative of the position or the shifting of the disc 2A or 
again of the duration of time interval chosen by the user. 
It will be observed that in the variant of FIG. 1 each pulse generated in 
this way corresponds to a period of the same duration (five minutes), 
whereas in the variant of FIG. 2 some pulses correspond to a small 
duration, while others correspond to a greater duration. 
FIG. 5 is a very simplified diagram of electrical connections of a circuit 
which can be used in the watch shown in FIG. 1, that is to say the one in 
which the disc 2 presents a linear graduation. This circuit, which is the 
one shown at 6 in FIG. 1, comprises a part 6A specifically intended for 
indicating the official time and a part 6B which ensures the timer 
function in cooperation with the disc 2 and the switch 3 as well as the 
stem 8. 
In conventional manner, the part 6A comprises a quartz oscillator 17 
supplying a signal whose frequency is about 32 kHz. This oscillator is 
connected to a divider 18 one of whose outputs 18 is connected to the part 
6B of the circuit, the signal appearing at this output being constituted 
by a train of pulses in which these pulses are spaced apart by five 
minutes (0.03 Hz), at least in the example described here. The divider is 
connected in conventional manner to a shaping circuit 20 which is itself 
connected to a stepping motor 21 driving the hands 22 of the watch through 
the agency of a wheel train. 
The switch 3 is connected to an accumualtor circuit 23 which, in this 
example, is a simple forward and backward counter, the forward counting 
input 24 being connected to the contact 16 of the switch, the backward 
counting input 25 to the output 19 of the divider and the zero output 26 
to a warning device 27 supplying an audible signal, or some other similar 
signal, when the forward and backward counter 23 arrives at the 0 
position. This counter also comprises a reset input 28 to which the 
contact 15 is connected. The warning device 27 is provided with a timing 
set-up to ensure the production of an alarm signal during a certain time 
only, after the forward and backward counter 23 has reached its 0 
position. 
The operation of the circuit of FIG. 5 is as follows. When the user wishes 
to use the timer to fix an interval of time to be measured, it is 
sufficient for him to put the stem 8 into the second position represented 
in FIG. 1 and drive the disc until the figure corresponding to the desired 
duration in minutes appears behind the window 11. The switch 3 has first 
left the 0 position (FIG. 1) then to command the forward and backward 
counter in rhythm with the passage of the teeth 9 in front of the portion 
14a of the contact arm 14. The forward and backward counter has therefore 
registered a certain number of pulses corresponding to as many periods of 
five minutes as make up the space of time to be measured. Once this space 
of time has been set, the time base formed by the oscillator 17 and the 
divider 18 causes the countdown of the contents of the forward and 
backward counter 23 at the rate of one pulse every five minutes, the 
period to be measured being at an end when the forward and backward 
counter 23 arrives at 0. It is at this moment that the alarm 27 acts to 
warn the user that the space of time has elapsed. In this case, the 
reference period used is therefore five minutes, this period being 
obtained at a special output 19 of the divider 18. 
It can therefore be seen that the timer is totally independent of the 
indication of the official time, which continues to be displayed in a 
completely separate manner although the same time base is used in both 
cases. This means, however, that a timer without any indication of the 
official time can easily be devised, whether this be in the form of a 
piece having to be worn on the wrist or a piece of some other nature, 
because it is sufficient simply to omit the elements 20, 21 and 22 in FIG. 
5. Such a variant therefore comes expressly within the limits of the 
invention. 
In the limits of a wristwatch, the disc 2 can advantageously replace the 
date disc without considerably changing the design of the timepiece 
itself. It will be noted, furthermore, that the precision of measurement 
of the space of time depends ultimately on that of the time base, which 
can be very good, that is to say that of conventional quartz watches. In 
fact, the positioning of the disc 2 being ensured in steps due to the 
jumper and being translated into a pulse train, any pulse freshly acquired 
by the forward and backward counter 23 will give rise to the establishment 
of a period of exactly five minutes counted down by the time base 17,18. 
The precision is therefore in no way dependent on exact positioning of the 
disc 2 and the user does not have to worry himself about this. In 
conventional timers, on the other hand, the setting disc does not have 
well-defined positions, so that, above all in the case of small intervals 
of time, it is difficult to adjust it precisely in a position 
corresponding to the desired interval. Finally, adjustment of the position 
of the switch 3 with respect to the disc 2 is not critical because the 
signal is obtained by means of the jumper formed by the contact arm 14. 
Referring now to FIG. 6, there will be described the example of a circuit 
which can be utilized with a timer of the type shown in FIG. 2, that is to 
say in which the graduation carried on the disc is not linear. The obvious 
advantage of such a scale is that the user can set spaces of time of very 
short duration and very long duration by using the same setting system, 
the invention acquiring the special feature that, whatever the period 
chosen, the precision remains always linked to that of the time base 
which, as already indicated, can be very good. 
The elements already described in connection with the preceding Figures are 
found again in FIG. 6, that is to say the chain for indicating the 
official time with the time base 17, the divider 18, the disc 2A, the 
switch 3 with its elements 14 to 16 and also the stem 8 enabling the disc 
2A to be positioned. It will be observed that here likewise the timer can 
be used independently or be associated with a device indicating the 
official time, as in the case described hereinbefore. 
In the circuit of FIG. 6 there is likewise provided an accumulator device 
for the pulses which are generated when the disc 2A is set in rotation by 
means of the stem 8. This accumulator device comprises in this case a 
counter 29 whose counting input is connected to the contact 16 and whose 
output represents in a plurality of bits the number that the counter 
contains. This output is connected in parallel to the address inputs of a 
permanent memory 30 which constitutes a scale conversion matrix. 
Consequently, the position of the counter 29 constitutes the address of 
this matrix which, in each of its bytes, stores a number corresponding to 
the duration of the intervals of time to be measured. This number may be 
expressed, for example, in minutes or in any other desired unit of time. 
In the present case, this unit is the minute. Thus, to each address of the 
memory 30 there corresponds a certain number of minutes, so that as a 
function of the contents of the bytes of the memory a "scale conversion" 
as it were can be obtained with respect to the successive steps that the 
disc 2A makes when it is set in rotation with the aid of the stem 8. On 
that account, the "conversion factor" may be any whatsoever for each step 
of the disc 2A, because according to the prior programming of the memory 
any number whatsoever of minutes to be counted down by the timer may 
correspond to each number accumulated in the counter 29. This arrangement 
therefore provides great flexilibity of carrying into effect of the timer, 
the sole limitation on design being the number of steps that the disc 2A 
can make and the capacity of the counter 29 and of the memory 30. In the 
case represented, which is that in which the timer is incorporated in a 
wristwatch and in which the disc 2A replaces the date disc, the number of 
positions of this disc is advantageously thirty-one, which permits the use 
of a disc whose construction is absolutely identical to that of a 
conventional date disc apart, of course, from the inscriptions which are 
carried thereon. 
The data output of the memory 30 is applied in the form of an eight-bit 
word, for example, to one of the inputs of a comparator 31, the other 
input of which, likewise an eight-bit input, is connected to a counter 32 
intended to receive counting pulses at its counting input from a dividing 
circuit 33. The output of the latter supplies a pulse every minute, for 
example. The corresponding pulses pass through an AND gate 34 permitting 
the passage of these pulses which are supplied in reality by the time base 
of the timer. 
The output of the comparator 31 is connected to an AND gate 35 for 
permitting the passage of the signals commanding the alarm generator 27. 
This AND gate is also connected to an oscillator 36 which is intended to 
supply a train of pulses to the device 27, this train of pulses being able 
to give rise to an audible alarm signal of any nature, as is well known in 
the art. 
In addition to the contact 16 being connected to the counting input of the 
counter 29, it is also connected to the reset input of the divider 33 in 
order that, after the emission of each pulse by the switch 3, the 
countdown of the period of time to be measured can commence at the 
beginning of a minute. In fact, it will be observed that, the divider 18 
supplying a signal with a frequency of 0.5 Hz, the divider 33 divides this 
signal by 30, so that its output supplies a pulse every sixty seconds. 
The contact 16 is also connected to a first input of an OR gate 37 whose 
other input is connected to the output of the comparator 31 and whose 
output is connected to the reset input of the counter 32. The latter is 
therefore reset either when the switch 3 emits a pulse or when the 
comparator establishes equality between the contents of the counter 32 and 
the data output of the memory 30. 
The contact 15 is connected to the reset input of the counter 29 and also 
through the medium of an inverter 38 to a second input of the AND gate 34. 
In other words, when the disc has been brought back to the 0 position, the 
counter 29 is reset and the pulses of the time base can no longer reach 
the counting input of the counter 32. 
The activation of the alarm signal generator 27 is subject to certain 
conditions. Thus, the output of the comparator 31 which initializes the 
production of the warning signal is connected to a timing circuit 39 with 
a duration of ten seconds, for example, which is connected to one of the 
inputs of the AND gate 35 through the medium of an inverter 40. This gate 
is therefore conducting only during the on time of the timing circuit 39, 
so that the signal coming from the oscillator 36 can be transmitted to the 
generator 27 only during this time. 
In the embodiment shown in FIG. 6, the timer comprises with advantage a 
shock detector 41 incorporated in the case of the timepiece and supplying 
a signal when the user applies a shock to the latter. The output of this 
detector is connected to the reset input of a flip-flop 42, the output of 
which is connected to a fourth input of the AND gate 35 and the triggering 
input of which is connected to the output of the inverter 40. This shock 
detector 41 is of the type which must be activated by an activating input, 
which is achieved in the example described through the medium of an OR 
gate 43, a first input of which is connected to the output of the 
comparator 31 through the medium of a timing circuit 44 set at a few 
seconds, the other input of the OR gate 43 being connected to the 1 Hz 
output of the divider 18. In this way, the detector 41 is activated 
periodically or an instant after establishment by the comparator 31 of 
equality at its two inputs. Thus, it is possible for the user to stop the 
production of the alarm signal even within the period of time set by the 
timing circuit 39. 
The example of FIG. 6 also comprises a subtracter 45, a first input of 
which is connected to the output of the counter 32 and the other input of 
which is connected to the data output of the memory 30, so that this 
subtracter can set up at its output a number which is the difference 
between the number of minutes already counted down and the number of 
minutes having to be counted down in all. The output of the subtracter 45 
can thus be connected to a decoder 36 connected to a display device 47 for 
the time which still remains to be counted down. This display device could 
be constituted by a liquid crystal display or any other similar system. 
In the fashion of the fitting of a day disc, the mechanical construction of 
which will be described in detail later on, the example of FIG. 6 further 
comprises a second disc 48 disposed concentrically inside the disc 2A and 
bearing on its face visible below a portion of the window 11 three 
indications corresponding respectively to the "off", "1.times." and 
"repeat" functions, Mechanically, this disc 48 is coupled to a switch 39 
having three positions corresponding respectively to the indications 
carried on the disc 48. The movable contact 50 of this switch is connected 
to earth, while one of the fixed contacts 51 is connected to an inverter 
52 and a fourth input of the gate 34. In this way, when the switch 49 is 
in the corresponding position, the time base pulses coming from the 
divider 33 can no longer reach the counter 32. Moreover, this same signal 
resets this divider 33 through the medium of the inverter 52, the counter 
32 being also reset through this inverter and the OR gate 37. 
The other fixed contact 53 of the switch 49 is connected to a first input 
of an AND gate 54, the other input of which is connected to the output of 
the comparator 31. The output of this same gate is connected to the reset 
input of a flip-flop 55, the triggering input of which is connected to the 
contact 16 of the switch 3. 
This circuit operates in the following manner. When the discs 2A and 48 are 
located in their "zero" and "off" positions, respectively, the switches 3 
and 49 are bearing on their contacts 15 and 51, respectively. All the 
circuits and in particular the counters 29 and 32 are then reset. 
In order to measure a space of time, the user first puts the stem 8 into 
the second pulled-out position (that is to say that in which, in a 
conventional watch, it enables the dates and days to be set or adjusted). 
By turning the stem in one direction, the user shifts the disc 48 towards 
the "1.times." position, then by turning the stem in the other direction 
he selects the duration of the space of time by observing the figures 
moving past in procession behind the window 11. As soon as the spring 14 
leaves the notch 10 (FIGS. 1 to 3), the change-over switch 3 leaves the 
contact 15 and, passing in front of the teeth 9, pushes its arm against 
the fixed contact 16, the result of which is the emission of a number of 
pulses corresponding to the number of steps carried out by the disc 2A. 
This number is recorded in the counter 29. At the same time, the addresses 
of the memory 30 are run through in succession until, when the disc 2A 
stops, the address is reached at which the time value corresponding to the 
chosen space of time is recorded. As soon as the disc 2A has stopped and 
the switch 3 is again immobilized in its neutral position, the AND gate 34 
allows the time base pulses (reference periods) to pass through and these 
are applied in this way to the counter 32. This therefore begins to count 
at the rate of one step per minute. When there is equality between the 
contents of this counter and the number supplied by the memory 30, the 
comparator signals the equality and supplies at its output a signal which 
opens the AND gate 35. The sound generator 27 is then activated as already 
described hereinbefore. As soon as the comparator establishes equality, 
the counting of the time base is inhibited through the AND gate 54 and the 
flip-flop 55, which closes the AND gate 34. The user can stop the sound 
generator 27 at will with the aid of the shock detector 41. In fact, this 
detector can cause the flip-flop 42 to change over and thus close the AND 
gate 35. It will also be observed that this gate remains open only during 
a predetermined time fixed by the timing circuit 39 which is connected to 
one of the inputs of this gate through the inverter 40. 
If, at the outset, the user has placed the switch 49 in the "repeat" 
position, the AND gate 54 is closed and the equality signal of the 
comparator cannot reach the flip-flop 55. On this account, a fresh 
count-down of the space of time can occur. 
So far, two embodiments have been described in which the disc 2 or 2A can 
be shifted only for setting the space of time to be measured, so that this 
disc cannot itself give evidence of the time which still remains to be 
counted down. 
On the other hand, in the embodiment which will now be described, the disc 
2 has the dual role of enabling the user to set the space of time to be 
measured and of indicating, during the measurement of this space of time, 
the period which still remains to be counted down. In FIG. 7 there is 
shown a method of driving the disc 2 which, in other respects, has the 
same form as that of the version of FIG. 1. However, in this case, a 
stepping motor 56 is moreover provided which, through the medium of a 
transmission wheel and pinion 57, drives a wheel 58 provided with a dog 59 
cooperating with the teeth 9 of the disc 2. The stepping motor 56 can be 
supplied with a frequency of 32 Hz, for example. Of course, the disc 2A 
can be provided with an identical mechanism. 
FIG. 8 shows an example of an electronic circuit which can be used in this 
last case. The elements already described in connection with FIG. 6 are 
shown in this Figure with the same numerical references. The circuit which 
is connected to the contact 16 of the switch 3 and to the memory 30 is in 
this case a forward and backward counter 60 which counts the pulses 
originating from the switch 3 and deducts the output pulses of the 
comparator 31. The latter is connected as before to the data output of the 
memory 30 and to the output of the counter 32, the latter counting the 
pulses coming from the divider 33 at the rate of one pulse per minute. 
However, the contents of the memory 30 are not the same as those of the 
memory 30 of the embodiment of FIG. 6. In fact, in this instance, to each 
address of the memory 30 there corresponds a value which is the difference 
between two successive durations displayed on the disc 2A. 
Thus, when the comparator 31 establishes equality between the contents of 
the counter 32 and of the data output of the memory 30, it applies an 
output signal to an AND gate 61, the other input of which is connected to 
a 32 Hz output of the divider 18. The output of this AND gate 61 is 
connected to a control of the motor 56. Consequently, in the case of 
equality, the motor 56 is activated by 32 pulses to bring the disc 2 or 2A 
one step backward. 
The meshing ratios between the rotor of the motor, the wheel and pinion 57 
and the wheel 58 are chosen in such manner that the 32 pulses are 
sufficient to cause the wheel 58 to make one revolution. In its 
inoperative position, the latter is located in such manner that the dog 59 
is in the position 59A shown by a chain-dotted line (that is to say in 
which this dog escapes the toothing of the disc 2 or 2A). Thus, the dog 59 
does not oppose the setting of the disc through the agency of the stem 8, 
which is coupled thereto by the conventional setting mechanism (not 
shown). However, as soon as the motor 56 is activated, the dog 59 knocks 
against a tooth of the disc to cause it to move back by one step (which 
transitory position is shown in FIG. 7). 
During this reverse movement of the disc, the switch 3, in spite of the 
fact that the contact 16 again records a pass in front of a tooth 9, 
remains inoperative for increasing the contents of the counter 60, since 
the output of the comparator 31 inhibits the counting input thereof 
through an inverter 63 and an AND gate 64. WHen the comparator 31 
establishes equality, the counter 31 is reset. 
Thus, at the end of the measurement of an interval of time corresponding to 
a graduation of the disc, this is brought back one step, the memory 
supplies a fresh value and the counter 32 recommences to count the pulses 
of the divider 33. 
The forward and backward counter 60 also comprises a "0" output which is 
activated when its contents reach zero. This output is connected to an AND 
gate 65 which commands the alarm device 27. This gate is also connected to 
the oscillator 36, the shock detector 41 and the timing circuit 39 
(limitation of the alarm time), the shock detector being associated with 
its own timing circuit 44. 
The zero signal of the forward and backward counter 60 is also transmitted 
to an AND gate 66 through the medium of an inverter 67 in order to block 
any fresh counting by the counter 32. 
Moreover, in returning to zero, the disc 2A restores the switch 3 to the 
position in which the contact 15 is activated. This can reset the forward 
and backward counter 60 in the event of the user wishing to put an end 
prematurely to the operation of the timer. 
In the variant of FIG. 8, the disc 48 can obviously also be designed for 
carrying out the "off", "1.times." and "repeat" functions by utilizing 
circuit elements identical to those appearing in FIG. 6. 
FIGS. 9 and 10 show an embodiment of the mechanism associated with the disc 
48. This is designed so as to be able to occupy a multiple of three 
positions (nine in this case) corresponding each time to the 
above-indicated functions. As in the case of a conventional day disc, 
thees positions are fixed by a jumper 68 and a star wheel 69 which in this 
instance has nine arms and with which a wheel and pinion 70 meshes. The 
latter forms part of the setting mechanism (see FIGS. 1 and 2) and is 
movable rotatably and also in translation due to a guide 71 of bean shape. 
In this way, in well-known manner, the stem 8 (not shown here) can drive 
the star wheel 69 when it is turned in one direction and drive the disc 2 
or 2A when it is turned in the opposite direction, the wheel and pinion 70 
then moving from one end of the guide 71 to the other. The star wheel 69, 
which is naturally fast with the disc 2 or 2A, is fixed to it through the 
medium of a three-level peripheral cam 72 with which the contact spring 73 
of the switch 49 cooperates. It will be understood that in this way each 
of the positions of the disc 48 corresponds to one of the three possible 
positions of this switch 49. 
As can be seen in FIGS. 9 and 11, the discs 2, 2A and 48 can be located 
directly below the dial 74 of a watch provided with the timer and 
indicating the official time with the aid of its hands 75 and 76. 
However, the timer according to the invention can be used independently 
without a device indicating the official time being necessarily associated 
therewith. 
Finally, it will be noted that the embodiment of FIG. 8 can be applied in 
the case where the disc comprises a linear graduation. It is then 
unnecessary to use the memory 30, the comparator 31 or the counter 32. On 
the other hand, a direct connection 77 (FIG. 8) must then connect the 
divider 33 to the control circuit 62 of the motor 56.