On June 22nd, 2021, Rolex was awarded a United States patent on the pictured inventio: an redesigned spring for watch movement.
Springs can be a pain in watchmaking. They take up a lot of space in the movement, they are difficult to install, and often fragile. Not to mention that they tend to fly across the room when mishandled.
So, Rolex proposed an interesting solution in their December, 2016 patent application. The picture above shows the basic idea. It's an arbor with a spring around it. The spring has stops against a housing around the arbor, and can either be pre-stressed or not. So, when a rotational force is applied to the arbor (15) or a wheel attached to the arbor (12, 12'), it will tighten or loosen the spring (depending on pre-stress).
In the picture above, the spring would be attached to the arbor (25). In this case the yoke spring, which is normally a large piece, instead takes up a small amount of space where the arbor of the yoke would be anyway. This eases installation and repair, though increases manufacturing costs – which are not traditionally a big concern for Rolex.
In 2016, Omega filed a patent application for a dial with luminous indices. Not totally unusual, you say. However, these are illuminated via an electric light source (likely an LED) under the dial. The patent discloses a switch in the bezel that activates the illumination.
The patent has been granted in China, Japan, and in the European Patent office, but is still pending in the US.
Interestingly, the design kind of reads like a compromise in order to get the patent issued. The patent (as issued in the European Patent Office) requires that the illumination source be under the dial but above the movement, and then connected to a printed circuit board below the movement.
It also doesn't describe what the power source is, though it would be very cool if it could be powered by some capacitors and resistors, charged from movement of the watch, rather than relying on a battery within the movement.
In the end, I worry that the restrictions of having multiple printed circuit boards would make this watch too thick to be particularly viable - especially given that many Omega watches already run thicker than comparable watches without a co-axial escapement.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
In the 1970s, Certina had a problem. There were already watches that were sealed and at low pressure to minimize oxidation of the gears and lubricating oils, but they were less accurate than other watches. Moreover, they were impossible to adjust while they were still sealed.
So, Certina sought a way to adjust a fully sealed watch. And this is what they came up with.
Certina put two bimetallic strips on either side of a regulation point, when heated, the bi-metaltic strips would push on the regulation point, adjusting the speed of oscillation.
You may be familiar with bimetallic strips from older-style thermostats. They are exactly what they sound like. A strip of two metals, joined together. Because they are not the same, the metals expand differently when heat is applied, and the metal curves. For a thermostat, it typically has a mercury switch on one side, so when it bends too much in one direction (or unbends) it will turn the heater on or off.
Similarly here, these two bimetallic strips are able to be heated from the outside of the case, and then bend to adjust the oscillation of the movement and make a more accurate timekeeping device.
You probably don't think too often that you need slightly different moon phase mechanisms for a watch in the northern hemisphere compared to the southern. In fact, all you need is for the moon phase wheel, the wheel that has the moon on it, to rotate in the opposite direction: right to left on most watches.
In most watches, this would just be a matter of adding a gear, or assembling the mechanism differently. But what, Breguet asks, what do you do for someone who travels from the northern hemisphere to the southern, or vice versa?
Well, for that world traveler, who only wants to bring one watch with them, Breguet has an answer: a moon phase mechanism with counterrotating wheels, two heart cams, and a selection mechanism to engage one or the other.
This is an interesting patent in that it may do fewer new things than any other modern patent we've featured here. It's basically two moon phases, with a selector between them. The heart cams allow the selection lever to engage one wheel or the other.
Like many of the patents here, this one is unlikely to see manufacture. It's not a really meaningful improvement on the existing mechanisms, and has incredibly limited real world use.