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Rotating and stationary shaft need to be engaged without slip

  1. Nov 28, 2013 #1
    Hi guys,
    So here's one thing which I want to design and this thing involves a flywheel rotating at about 1000 rpm. I need to transfer this energy to another shaft which is stationary with a mechanism. The mechanism has to be actuated for only a second, and then disengaged. During engagement, the two shafts - driver and driven shaft have to be coupled but without slip (positive engagement as we call it).

    Is there any mechanism by which I can do this?
  2. jcsd
  3. Nov 30, 2013 #2
    A clutch.
  4. Dec 2, 2013 #3
    Use a Clutch. It is meant for this purpose.
  5. Dec 3, 2013 #4


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    Clutches do have a limited amount of slip and if the engagement period is short, that might be material.
    The OP does not give any guidance as to how much slip is acceptable, but it may be that he needs something else. He needs to specify his requirements more precisely.
  6. Dec 4, 2013 #5
    Hi again.
    Sorry if the requirements seemed incomplete. But what I do need is a positive drive without slip. The torque (& power) has to be transferred to driven shaft almost instantaneously (order of milliseconds or less to get full torque).
    Also the input is continuously rotating while the output has intermittent (single or half revolution) motion.
    Is there a specific device which does this?
  7. Dec 4, 2013 #6


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    I think you are looking for a device called a dog clutch. This has two interlocking pieces, and when activated the two shafts are locked together so they can't slip.
  8. Dec 4, 2013 #7


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    Staff: Mentor

    What is the final RPM? How much energy is transferred and how fast? Have you calculated the torque that generates?
  9. Dec 7, 2013 #8
    Thanks phyzguy and Russ...
    Dog clutch is actually a good suggestion...but from what I know is that dog clutch operate at low speeds...
    The speeds that I want to operate the mechanism is roughly 2000 rpm. The energy involved is around (roughly) 9500J. This is the flywheel energy and flywheel speed. This speed would be geared down, but the this energy has to be transferred in a fraction of seconds..say 0.5 or 1 sec to the mechanism.
    Any more suggestion, guys?
  10. Dec 12, 2013 #9


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    Sounds like a Geneva mechanism might work depending on how much you need the stationary shaft to rotate.
  11. Dec 13, 2013 #10


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    You could use hydraulics. A gear pump on the flywheel could circulate fluid through a hydraulic motor attached to the shaft. A shunt between the two hydraulic lines would idle the system. When the shunt is blocked by a sliding spool valve, (for one second), the pump will couple directly to the motor.

    If early shaft movement is a problem then a sacrificial shear pin through the shaft would prevent any rotation prior to complete obstruction of the shunt.

    The gear pump on the flywheel could also be used as a motor to spin up the flywheel by using a constant pressure hydraulic power pack.
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