The stop watch with catching up with.

Any typos are as a result of direct translation of the original French.

Definition and use of catching up with.

In a stop watch with catching up with there is one second needle known as "switches catching up with" which is superimposed on the second hand of the stop watch.

When the push rod of stop watch is actuated, the needle of catching up with remains superimposed on the second hand, merging with it, in the same way when the second hand is stopped like during its restoring.

On the other hand, if after having started the second hand, one actuates the additional push rod of catching up with (in part IWC opposite, it is to 10 H), the needle of catching up with stops while the second hand continues its walk.

Then, after having carried out the reading of the observation,
a second pressure on the push rod of catching up with brings back the needle of catching up with on the second hand, the two again superimposed needles going, until,

by a third pressure on the push rod of catching up with, one again immobilizes the needle of catching up with.

The use of catching up with is thus indicated for the timing of a test, in which several runners are in track, since one has the possibility of stopping the needle of catching up with, on arrival of each runner, which facilitates the reading of the observation, then to make "catch up with" with the immobilized needle the downtime.

Terminology

With	Coil with column
B	Hook
C	Rock
D	Saltire of wheel with column
E	Grip catching up with
F	Grip catching up with
G	Coil catching up with
H	Comes out from grip
J	Lever
K	Comes out from lever

Operation.

In a stop watch with catching up with located side of the bridges, three wheels swivel in the center of the movement:

The wheel of center L whose pinion is bored.
The wheel of stop watch carrying two hearts.
The wheel of catching up with G.

The wheel of catching up with, to ensure greatest possible freedom does not swivel in a stone, but comes to butt under against - pivot of the bridge of catching up with.

rattrapante dessus.png (89 Ko)

Go:

When the stop watch functions the wheel of stopwatch involves the wheel of catching up with which it, is also free.
The roller in ruby remains in the notch of the heart of catching up with.
The two needles are one on the other.

rattrap dessus fermer.png (20 Ko)

Stop of catching up with:

When one presses on the push rod of catching up with the grips come to block the wheel of catching up with but, the continuous wheel of stop watch to advance as well as the heart of catching up with fixed on this one.
The roller which him, is fixed under the serge of the wheel of catching up with then starts to go up on the heart of catching up with.
The needle of stopwatch advances, the needle of catching up with is stopped.

Correction of the needle:

One presses second catching up with once on the push rod of, the grips releases the wheel of catching up with.
The roller, while supporting on the circumference of the heart, by the effect of its spring makes catch up with the needle while coming to position in the hollow of the heart as in the position goes.

Of this position to this one

Conditions of correct operation:

The "slope" of the heart should not be too stiff (significant couple), nor too soft (return not Net of the needle).
The spring K should not be too strong (risk of stop), nor too weak (risk not to make turn the wheel of catching up with).
The spring doubles H (image of the beginning) swivels on a screw to range, which causes identical forces on the grips of catching up with E and F.
The functions of stop (grips between the columns) and of catching up with must be carried out after the moment of the explosion, if not one could stop the needle or operate the function of simply catching up with while pressing slightly on the push rod.

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