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Omega bumper

  1. simon

    simon Jul 25, 2012

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    Maybe a supid question, but why do they call a bumper movement BUMPER? Thanks for answers already. Greetz Simon
     
  2. MSNWatch Ω 2

    MSNWatch Vintage Omega Aficionado Staff Member Jul 25, 2012

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    The typical modern automatic watch has a rotor that swings a full 360 degrees while the bumper movement has a rotor that swings perhaps 120 degrees or so and "bumps" springs on either end. This bumping is something that can usually be both heard and felt. It is usually not as efficient as the full rotor movements at restoring the power reserve of a watch but properly serviced and cared for can be a robust movement in its own right.
     
  3. dsio Ω 2

    dsio Ash @ ΩF Staff Member Jul 25, 2012

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    Isn't there some advantage to it in ultra thin applications, as the winding mechanism can sit on the same vertical plane as the hammer, while in a rotor setup the winding mechanism has to sit beneath the rotor. Would also imagine the bearings the hammer rotates on would be superior as in a rotor you have an unbalanced mass spinning on a single ended shaft, while in a bumper the shaft it rotates on could be secured above and below (I'm no watchmaker, but that's what I see as an engineer).
     
  4. MSNWatch Ω 2

    MSNWatch Vintage Omega Aficionado Staff Member Jul 25, 2012

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    I believe for the ultrathin applications the microrotor is used like the polerouters of UG and used by modern day companies like patek and chopard.
     
  5. ulackfocus

    ulackfocus Jul 25, 2012

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    Bumpers don't make great ultra-thins because they must be built sturdy to withstand all the pounding. Microrotors are better but can have winding issues with such a small rotor since it has to be so heavy. The single pivot can wear out simply securing the very heavy mass of the rotor so a dual pivot with a bridge over the top (like the 12P) will out last any single pivot. The 360˚ rotor is the most efficient design for winding but that means the plates & bridges have to be even thinner and can flex which leads to problems. Thin isn't as simple of a complication as most think.
     
  6. N2FHL

    N2FHL Omega Qualified Watchmaker Jul 25, 2012

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    These bumpers only go about half a turn in each direction, only wind in one direction and are also an unbalanced mass. Because of the limited motion available to actually wind the movement, there is much more torque on the winding wheels to get the job done. Although supported on both ends, the axles still come in broken. All this said, they seem to work well when properly maintained, but lack of maintenance creates special problems with these. Once the pivots start to get dirty the extra torque causes them to grind away. Soon the parts become loose, the weight starts to drag on the back of the case and eventually some of the parts just have to be replaced.

    Steve