Chronograph wristwatches Landeron caliber and Venus caliber

Landeron Caliber

In 1940, Ebauches SA, owned since 1927 by Charles Hahn & See of Landeron, patented the crownless chronograph (no. 209394), which required three pushers, one for each function.

Z53 has 16 start buttons for zero setting,
It shows a (slightly revised) patent drawing including stop buttons 17 and 18 on the crown.

The crown lever 14, which is actuated by all three buttons,
Lead to zero setting the heart piece lever 8 having two "striker surfaces" 9.

The carrier arm 5, which is pressurized by a spring 7, is positioned against the screw 12 of the heart piece lever.
The set screw 15 forms a mount for the crown lever 14.
The positions of the heart piece lever 8 on the two levels 20 and 21 are
It is determined by the bet of 19.

Naturally, the zero setting position does not remain against the heart piece behind the zero setting (Fig. 3).
It is pushed back into its rest position by the latch 19 (step 20).

In this position (fig. 2), the central chronograph wheel is unstable and
It is only held in place by a small spring.
The blocking lever was probably omitted to save money.
This patent states that zero setting occurs when the start button 22 is pulled.
A second layout (Z54, Fig. 4) is shown in an even simpler form (Fig. 5).
This was not a particularly practical system.

Similarly, here the zero setting was inaccurate since the striker of the heartpiece lever 8 was again automatically lifted by the latch 19.
Nearly a year later, an additional patent (No. 216336) was filed which specified that the heart piece lever 8, after having been actuated for zero-setting by button 18 on the crown, rests on heart pieces 10 and 11 until it is initiated again by button 17.
The mechanism for button 3 was initially retained,
Every function was activated separately with its own button.

New features of technological advances include:
Latch 19 (originally located to the right of heart piece lever 8, see Z53) After zeroing,
Heart piece lever 8 was pressed and moved to the left side of heart piece lever 8 (Z55, Figure 1).
Thus, striker 9 remains in heart pieces 10 and 11,
As a result, the latter was kept at zero setting.
This function acted like a blocking lever.

Depra Patent

Marcel Desplat is probably

Separate button for zeroing

I realized that it has its advantages,

Pressing it accidentally right after starting had no effect.

In design,

In 1940, he introduced the three-button zero-setting chronograph

It was noted that this can only happen after a stop

We have obtained patent number 210862.

Z 56, Figs. 1 and 2 show that the starting arm 14 is connected to the auxiliary lever 27

and Heart Piece Lever 20 so that they work together

Shown are the patent drawings shown.

Figure 1 shows the starting position, Figure 2 shows the stopping position.

The auxiliary lever 27 is attached under the screw 28.

It functions as a locker,

The spring 33 forces the pin 31 to rotate to the left.

Pin 29 rests on the outer edge of heart piece lever 20.

After being started by pressing button 16,

Heart Piece Lever 20 is in the leftmost position.

At this time, the pin 29 of the heart lever 27

It's in the Heart Lever hasp 30.

If button 18 on the crown is pressed for zero setting,

The heart piece lever 20 is held by the pin 29 of the auxiliary lever 27.

Since it is held back, the initiating arm 14 cannot actuate.

Therefore, it is not possible to immediately zero the device immediately after starting.

First you have to press button 17 for the stop function.

In this case, the auxiliary lever 27 with the pin 29 (FIG. 2)

The transmission wheel 9 is connected to the central chronograph wheel 3

Release the heart piece lever

First, move the heart piece lever out from latch 30,

The transmission wheel 9 releases the heart piece lever of the central chronograph wheel 3.

After this stop function, zero setting is possible by pressing button 18,

The Heart Piece lever will immediately move to the rightmost position,

It is held by a catch spring 24.

Press the start button again until it touches the surface of the heart piece.

This well-developed three-button chronograph

Because buyers preferred the model with only two buttons (based on patent number 216602),

I was a late entrant into the series' production.

It is unclear whether this occurred due to cost differences or ease of operation.

The basis for this three-button version was the later Landeron caliber 47.

Two-button chronographs were already popular,

Depraz patented another three-button chronograph in 1942 (number: 232948).

As you can see from the patent drawings, the Z 57 does not have a minute counter.

Unlike normal transport arms, the transport arm 8 (black)

It was attached to the screw 9 inside the line of the drive wheel and transmission wheel.

The start arm 12a does not have a return spring,

Button 14 or 15 remained released.

After stopping by pressing button 14,

By pressing button 5 in the crown,

For the central chronograph wheel heart piece 3

Heart piece lever 4 is pressed down,

As a result, the chronograph hand was set to zero.

The design was a simple and economical chronograph with only a centrally stoppable seconds hand.

Jaco Guyot Patent

Then, an integrated lever with two strikers
Because it was necessary to hit two heart pieces at the same time,
The new design of the heart piece lever, without the crown wheel, required special precision as before.

In mass production, only one of the two pieces fits tightly onto the surface of the heart piece,
The other one was not contacted,
The heart piece had a playful element to it.

As a result, the number of applicable property holders was not exactly zero, but there was some variation.
Many designs have been developed to avoid this situation.
Most of them have a two-part spring-loaded heart piece lever made in one piece.

Henry Jacquot Guillot of Neuchâtel received a patent (number 213644) for a heartpiece lever with a moving striker in 1941.
This ensured very accurate zero setting (Z 58).
The striker can be aligned with the heart piece,
There was no need to adjust the individual strikers.

Designed by Jaco Guillot, based on patents no. 209394 and no. 216336,
Three buttons are required for start, stop and zero setting,
You could also start directly by pressing button 10 immediately after button 9.
This feature was not necessarily seen as a positive technological advancement.
If button 10 is pressed by mistake,
The time that was kept has (unfortunately) disappeared.

People were used to the two button crown chronographs,
The three-button method used here was not only expensive but also cumbersome.

This insight led to a further patent no. 216602 in 1941 for a two-button mechanism (Z 59).

The differences from the previous patent (Z 55) are:
The initiation arm 30 only provides the initiation function when the button 28 is pressed.
Button 29 activated both the stop and zero functions.

To activate both functions using button 29,
An end 36 and a point 37 of the auxiliary lever 34 were required.

The heart piece lever 8 must be provided with a latch 38 (Fig. 2),
The effects will be discussed later.
Initiation was accomplished in the normal manner by pressing button 28.

When timing is stopped by pressing button 29,
The edge 36 of the auxiliary lever contacts the crown lever 30 attached to the screw 31,
It was positioned so that it would lock when nose 37 contacted notch 38.

During this movement, the contact between the drive wheel 4 and the central chronograph wheel 1 is broken,
The needle stopped moving.
However, the latch 19 continues to press against the angle at point 26,
The heart piece lever was under spring tension on the right.

When button 29 is pressed, spring 35 lifts auxiliary lever 34 having nose 37 from contact at point 38 on the heart piece lever,
Point 26 is stopped by bet 19.

During this process, point 38 of the heart piece lever 8
When button 29 is pressed again, the nose is pressed directly onto the heart piece lever,
It passed just below nose 37 which lifted it out of the notch at point 26.

The released heart piece lever moves forward rapidly in the direction of its rotation,
When the striker head contacted heart pieces 10 and 11, it activated the zero setting.

Using this mechanism,
Two buttons allowed for reliable zero setting or starting and stopping.
This final design would later become the Landeron Calibre 48 and was mass-produced.

However, the development did not stop with the Landeron caliber.
Further minor improvements (to reduce costs) were included, as many other calibers followed suit.

Venus Calibur

Later versions of the chronograph, equipped with a crown wheel,
One button for both start and stop functions,
It was customary to use one button exclusively for zero setting.

First, for chronographs without a crown wheel,
As already shown, the start arm (originally) consisted of one piece,
It was more or less attached halfway between two buttons so that it resembled a coffin.

In the 1940s, the Venus SA company introduced the
They introduced chronographs that didn't have a crown wheel like the crown wheel with a crown wheel.
Because of this I had to make a start arm out of several pieces.

This could act like a "changer".
The result is a jointed arc at launch.
The individual functional phases are shown in Z60, Figures 1-4.

Figure 1 of the Z60 shows the movement (Venus 188 caliber) with the chronograph mechanism displayed on top.
The mechanism is in a stationary position, meaning both the chronograph hands and the minute counter are at zero.

There is a start/stop button G on the top right and a zero setting button A on the top left.

The operating wheels and levers are as follows:
L = minute counter car,
D = changer,
H = zero setter,
B = star wheel,
N = Heart Piece Lever,
R = Heart Piece Lever Limiter Lock,
E&F = carrying arms,
M = changer spring,
0 = Minute counter wheels lock,
P = star wheel,
C = central chronograph wheel,
K = transmission wheel,
S = drive wheel. It should be noted that in order to examine the actual switching mechanism, the star wheel arm B and the minute counter wheel L are not shown in Figs. 2 and 3.
Heart Piece Lever N (attached to the Heart Piece Lever Limiter E)
is also removed so that the heart piece lever limiter E and the changer are now shown working together.

In the rest position (Fig. 2), changer D (dotted line)
The heart piece lever limiter E is always in the same position on tip E'.

When the start button G is pressed, the movement continues until the lock R restricts this movement.
The heart piece lever limiter E is pushed to the left (see arrow).
At this time, the end N' of the heart piece lever N is
The carrying arm F is released via the pin F',
The driving wheel K is always in momentary contact between the driving wheel S and the central chronograph wheel C.
When button G is released, changer D returns to its rest position (shown in dotted lines in Figure 2).
If tip E' is to the left of changer D, a new press of button G will
The Heart Piece lever limiter will move to the right (see arrow in Figure 3).
In this action, the tip N' of the heartpiece lever N lifts the carrying arm F on the pin F' which is in contact with the central chronograph wheel C, immediately stopping the chronograph hands.

This change between starting and stopping is
It can be repeated as often as desired by pressing button G to start or stop the chronograph hands.
It doesn't go back to zero.

In the park position, the zero setter H is located to the left of the heartpiece lever N.
When button A is pressed, pin H' of zero setter H pushes heart piece lever N,
Rotate mandrels L' and C' clockwise until the two ends touch and insert them into the heart piece (Figure 4).

In the outer position, both sides of the heartpiece contact the straight sides of the heartpiece lever,
Both hands (chronograph hand and minute counter hand) will reach zero.
In this position, the heart piece wheel will rotate until button G is pressed again and changer D is turned to the left.
It is held by lock R, which provides the starting function (Fig. 2).
It should also be noted that during the stopping and zero-setting phases, the pin F' is always in contact with the lower end N' of the heartpiece lever N and the carrying arm F.

During the zero-setting movement of the HeartPeace lever,
The star wheel P is moved so that it does not come into contact with the central chronograph wheel C,
It is moved against tip B' of star rocker B (Fig. 1 and Fig. 4).
As shown by the dotted lines in Figures 2 and 3, the heart piece lever N is
During starting (figure 2) and stopping (figure 3) the central chronograph wheel C and the minute counter wheel L are outside their effective range.

The way this Venus caliber works without a crown wheel is
It is exactly like a chronograph with a crown wheel and two-button mechanism.