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Tuesday, 26 February 2019 19:05

Ball's Fine Adjust Clasp

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Ball has a pending patent application for a bracelet clasp with an interesting toothed fine adjust. 

This clasp has a slider that allows it extend or detract, and then on the inside of the clasp is a series of teeth and stops that allow several points of fine adjustment. 

Ball has filed this application in China and the European Patent Office. It is still pending in both patents offices.

 

Wednesday, 20 February 2019 17:45

Swatch's On-Case Fine Adjust

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This is an interesting, though I think a bit impractical, way to adjust a bracelet or strap on a watch. Rather than having a fine adjust on a clasp, as is most common, this puts the fine adjust on the lugs, effectively. 

In the various embodiments of the invention, at least one set of lugs on case can be moved in or out slightly via a screw or slide. This would allow for minor adjustments to the strap over the course of a day.

Some, perhaps obvious, potential downsides of this would include that it makes design a little harder when there isn't a fixed lug-to-lug dimension. And the watch would have to look good with a variety of spacings. It would also make it practically impossible to have an end link in a bracelet that was flush against the case. 

Finally, for safety and function, the slide would have to be integral to the case, which would likely thicken the case of the watch pretty dramatically, though with a small movement in a larger case this issue could be minimized. 

Tuesday, 22 January 2019 22:00

Patek's Twin Spring Single Barrel Watch

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The barrel of the watch contains the mainspring, the wound piece of metal that provides the power for the watch to tick. Most watches get 36-40 hours of power from a fully wound mainspring. There are watches that have double barrels, and two mainsprings, to provide 80-100 hours of power. There are also some, more novelty watches, with several barrels and mainsprings.

Typically multiple barrels are placed in series to provide a more consistent power output over time.

And then there is Patek, with their 2013 patent on a single barrel with two stacked mainsprings. The main advantage Patek claims in their application is that by stacking them, you end up savings space. You can have a ratchet for winding on one side of the barrel, and a wheel on other for driving the movement, while still having the benefit of two springs.

I don't think this is particularly revolutionary, but it's an interesting space saving design. 

Monday, 14 January 2019 21:28

The 1956 Invention of the Micro-rotor

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The advent of the self-winding watch ushered in a new age of design in watches. It also increased the thickness of watches. In most designs, the rotor was concentric with the movement, and stacked below the gears. But there was a way to limit the increase in thickness, as Universal Perret Freres (later Universal Geneve) said eloquently in their 1956 patent application:

According to a primary feature of our invention, the rocking weight has its axis arranged eccentrically with that of the watch and it is arranged in superposition with the winding mechanism above the watch plate within the space left free on the latter by the mainspring, the movement and the balance wheel while the total height of said weight and winding mechanism is at least approximately equal to that of the movement.

This concept, of having the rotor co-planar with (at least part of) the movement, is what we now know as a micro-rotor. This patent (really, this one is worth a read) goes into some depth as the problems with alternative low-height winding mechanisms. 

The micro-rotor is still something of a niche item, but it's very interesting to see a patent describing it as early as the mid 50s.

Tuesday, 13 November 2018 20:21

Zenith's 1921 Patent on a Winding/Setting Stem

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I love this 1921 patent granted to Zenith for a couple of reasons.

First, the drawings are just a wonderfully straightforward depiction of a stem and crown that could be used for setting the hands (pushed in) or winding (pulled out). Second, it's always interesting to see an early version of something that's become such an integral part of watches today, and mores to see it in a slightly different light.

In the drawing above you can see the stem in the winding position, meshing with the top gear which would go to the power train. When pushed in, another set of gears on the stem mesh the hand setting mechanism. The leaf shapes help hold the gears together, and maintain the stem in a particular position. 

Wednesday, 07 November 2018 18:01

Tudor's Two-Way Adjustable Bracelet

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In this 2013 patent, Tudor discloses a fine adjustable watch bracelet that has both fine adjustment and elastic adjustment capabilities. While I try not to get too judgmental about these patents, I'm very surprised that this was issued.

The patent discloses two ways to adjust the fit of a bracelet, each at opposite ends of a wristband or clasp. 

The first is to attach springs in the bracelet. The springs allow the bracelet to stretch and return to its original position. This is something that was well-known in the art. 

The second is a series of grooves in the clasp, along with a bar which snaps into the grooves, also well-known in the art of fine-adjustment of bracelets. 

It's axiomatic that you can't combine two things, get the expected result, and obtain a patent on that. If already erasers existed, and pencils already existed, you usually can't get a patent on sticking an erase on a pencil. Here, I'm struggling to see what the point of novelty was, other than maybe the adjustments being at opposite ends of the clasp.

Regardless, it's an interesting, if not likely redundant, mechanism, that I don't believe we've seen in Tudors. 

Thursday, 01 November 2018 20:58

Hamilton's 1930s Antimagnetic Escape Wheel

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This is a patent that's very interesting for its historical context, and how clear the specification is about the problem it seeks to solve and how it solves it. This was filed in 1929 and issued in 1933 (don't let anyone tell you that long delays in getting a patent are a new thing).

The patent specification succinctly sums up what the problem was in the prior art, "As is well-known, a watch mechanism, or movement, containing parts of magnetic material, or which are sensitive to magnetism, or a magnetic field to which the movement is exposed, may have its accuracy impaired, or indeed under some conditions, its running may be stopped."

Steel was commonly used in the escape wheel to withstand the repeated hits from the pallet fork (pictured above) which may hit the escape wheel teeth three or more times a second. But steel wheels could easily be magnetized, and was susceptible to magnets. 

The most common anti-magnetic metal for use in gears was brass, but, "it is not hard enough to resist wear so that while its use for an escape wheel would eliminate the effect of magnetic influences, it would fail for want of wear resisting properties."

So, the inventor came up with a rather elegant solution. "I construct the escape wheel so that it has a main or body part of wheel-form, that is to say, a hub, spokes and rim or circumference, of a non-magnetic material, such as brass, and teeth of steel." There is a small enough amount of steel that it is largely unaffected by magnets, and the brass is just immune to its effects. Further, the combination of the metals, and their different coefficients of expansion as they heat are counteracted by the movement in the plates on which they are mounted.

 

 

Tuesday, 23 October 2018 20:55

Gruen's Day-Date Complication

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This Gruen Patent from 1972 is featured not because it's particularly groundbreaking, but because it does such a great job at showing one common way to implement day-date mechanisms. 

The day indicator is linked to the seven-sided star gear shown in the center, and it's advanced by the wheel to its left with a single finger. That wheel rotates once a day, and once a day rotates the star gear by 1/7th of a rotation, advancing a day wheel that shows the day of the week on the face of the watch.

Meanwhile in this implementation, the finger in the lower left will connect with the spurs on the date wheel around the edge. As it completes its rotation, it will advance the date wheel just like the date wheel does.

This particular implementation has a couple of interesting tweaks. The date cam is in a groove, so as it rotates around it also extends out a bit to better engage the spur. It also keeps the two wheels (day star wheel, and date wheel) in place with springs, that aid in limiting the movement to once a day when engaged by their respective cams.

Thursday, 18 October 2018 16:37

Chopard's Clever Balance Wheel Adjustment

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In 2003, Chopard was granted a patent on a clever system for adjusting a balance wheel on a watch. 

The most common ways of adjusting a balance wheel are a bit clunky. There are weights held on by pins. Screws that can be moved in and out, or removed entirely. Monochrome has a great article about this. All of these are to adjust the balance wheel's moment of inertia.

Think of the balance wheel like a figure skater. The skater takes a big push off, and starts spinning. At this point, the skater has some energy in the spin that is not going to increase. But, if the skater brings their arms closer to their body, they will spin faster. That's because by doing this they are reducing their moment of inertia - the energy it takes to spin - and spinner faster with the same amount of energy in the spin.

Similarly, the balance wheel is always getting a set amount of energy from the watch's power train. So to adjust its oscillation, you need to vary the balance wheel's moment of inertia. 

Enter the Chopard patent. It discloses small u-shaped weights that slot into holes in the outer rim of the balance wheel. By turning the weight at particular angles, you can adjust whether there is more weight toward the outside of the balance wheel (extending the skater's arms and increasing the moment of inertia) or closer to the center of the balance wheel (bringing the skater's arms in).

In a seeming rare case for this site, we can actually see that this patent is in use in a current Chopard watch.

Wednesday, 10 October 2018 21:32

ETA's Crown Function Display

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This is one of those patent's that is so simple and obvious that I was a little surprised not to have seen it before. I think this could be useful on watches with a million little complications, but then the question becomes where do you put the function indicator?

In this patent, the crown is connected to an indicator dial on the face of the watch. When the crown is pulled out to its first position, a finger engaged with the sleeve of the crown pulls a rack attached to the function dial. This rack and pinion connects the function dial on the face to the crown. 

One thing this doesn't account for is indicating how to turn the crown to adjust it when a given position on the crown controls two functions on the watch. I admit that every time I grab a day-date or a GMT watch with a date function I almost always rotate the crown the wrong way to adjust it first. As a result, my GMT watches are perpetually on some random timezone that I don't care a wick about.