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What was the reason behind the bumper automatic instead of

johnireland
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The full swinging rotor that Rolex used from the beginning (after they purchased the patent from Harwood)? Was it fear of copyright infringement? Everyone making an automatic movement in the 40s and 50s was doing the bumper models...including JLC and others...except Rolex...and their illegitimate son, Tudor Eventually everyone early went to the 360 degree rotor by the 1960s. Any answers or theories?
 
Tony C.
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johnireland johnireland
Was it fear of copyright infringement?

Patent infringement. No company would have attempted to break those laws.
 
TimeODanaos
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johnireland johnireland
Everyone making an automatic movement in the 40s and 50s was doing the bumper models...including JLC and others...except Rolex...and their illegitimate son, Tudor Eventually everyone early went to the 360 degree rotor by the 1960s.
But let's hear it for Eterna, who introduced their 360° rotor "Eterna-Matic" (cal 1198) to deserved acclaim in 1948. The five minute ball-bearings at its axis hugely reduced both mechanical friction and retributive litigation, and their watches continued thus equipped until the era of damned quartz.
 
Canuck
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The early Rolex Perpetual automatic rotor only wound in one direction. As did the bumper type automatic. I suspect that the bumper automatics of those years probably operated as well as the early Rolex Perpetual. Not much incentive to re-invent the wheel. Especially considering the Rolex patent.
 
Dan S
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As mentioned, the Rolex patent expired in 1948. After that, various manufacturers began to make full-rotor designs.
 
jjen
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The original Harwood winding system was a bumper movement with no crown and the time adjusted by turning the bezel
 
iamvr
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What about the Bydinator movements made by Felsa starting from 1942. Two watchmakers told me that Felsa was able to bypass Rolex' patent as their movements wind in both directions (hence the name Bydinator), the first one on the market, as opposed to the one-directional winding rotor patented by Rolex. Makes intuitively sense to me but I was not able to find any online resource discussing that matter specifically.
 
JimInOz
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The Bidynator was indeed an important development in automatic movement advancement, although it wasn't until about 1946 that Felsa had a fully bi-directional winder.

However, Felsa was also held back by patent barriers, so while others persisted with bumpers, Felsa continued research and development and patiently waited for patent expiry.
 
iamvr
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JimInOz JimInOz
The Bidynator was indeed an important development in automatic movement advancement, although it wasn't until about 1946 that Felsa had a fully bi-directional winder.

However, Felsa was also held back by patent barriers, so while others persisted with bumpers, Felsa continued research and development and patiently waited for patent expiry.

Many thanks, Jim, for this explanation.
 
johnireland
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Fascinating, thank you all. Back in those days, when the Rolex full rotor still only wound in one direction, it was still a more elegant solution to the bumpers with their weights bouncing off of springs. Bi-winding has been the rule for decades, it seems. But in the JLC Master Controls, they have found that even with a full freely swinging rotor, that winding in one direction has proven more efficient. I have my own thoughts on the less than useful 70 hour power reserves that are the trend. It might make sense if you had a watch with lots of complications but only wore the watch once every 2 to 3 days...or you get a watch winder. But if you wear a basic watch every day or every other day, the 30 hour power reserve has always been just fine. If the watch stops, you simply reset it.
 
UncleBuck
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Maybe it's the old hippie showing through, but I really dig the "bump" that connects me to the operation of my watch.

I wore a bumper daily for years and can't wait to get it back from service, it's been gone a while.

If I can, I'll always wear a bumper....... A repeater is the only thing I can think of that might connect a watch to it's partner in the same way.
 
Dan S
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Full-rotor movements with uni-directional winding are still widely used, e.g Valjoux 7750. I doubt that it they are more efficient, but it seems they are efficient enough on the wrist. However, bidirectional watch winders don't always keep them well-wound in my experience.
 
JimInOz
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Just an aside, and relating to John Harwood.

Such a small notice from a company known for huge publicity budgets.

HarwoodRolexApology.jpg
 
JimInOz
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Rolex was also guilty (in my eyes) of perpetuating the fact that Abram-Louis Perrelet invented the first automatic watch, and not Hubert Sarton.

RolexHarwoodPerrelet.jpg
 
UncleBuck
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Thank you for this significant history.
Jim, you, along with Ash and a few others, have picked up the torch and led this great hobby and have kept us grounded, informed and focused.
You know how much you have helped me, but you continually step up for all and make such significant contributions to the advancement and history of this hobby.
Well done my friend, and thank you for your tireless service to all things you hold dear.
Three cheers would not be near enough!
 
impalla62ss
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Dan S Dan S
Full-rotor movements with uni-directional winding are still widely used, e.g Valjoux 7750. I doubt that it they are more efficient, but it seems they are efficient enough on the wrist. However, bidirectional watch winders don't always keep them well-wound in my experience.

Kind of like the bumper, I enjoy the occasional rotor buzz on the Valjoux 7750.
 
JimInOz
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UncleBuck UncleBuck
Thank you for this significant history.
Jim, you, along with Ash and a few others, have picked up the torch and led this great hobby and have kept us grounded, informed and focused.
You know how much you have helped me, but you continually step up for all and make such significant contributions to the advancement and history of this hobby.
Well done my friend, and thank you for your tireless service to all things you hold dear.
Three cheers would not be near enough!

I'm just a very small wheel in a big machine Jimbo, there are others (as you noted) who keep the machine running so well.
 
UncleBuck
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As you have shown us, the small wheel is just as critical a part as the big.
A heartfelt thanks.
 
tamura
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For me, the nicest omega case designs have bumber movements.😀
 
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