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Thread: Rotating mechanical connection

  1. #1
    Senior Engineer
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    Rotating mechanical connection

    Hello folks,

    I'm working on a carrier gear (gear with extension for carrying a changeable roller with it) with a quick release type function. The gear is supported by 2 bearings on a fixed shaft. A roller is placed on the shaft to be carried by the gear. I need to be able to change out rollers quickly. There is an axial load on the roller. The bearings can be fixed on the shaft to handle this load, but I need a clever method of fixing the roll to the gear against this axial force.

    The best idea so far is (copied) a carrier shaft with three keys and a roll with 3 key-ways. Pressed into the carrier is a spring loaded retainer with triangular shape. The retainer is toothed against the carrier like a clutch to keep them rotating together. One must pull on the retainer against the spring to disengage and rotate the triangle in alignment with the keys to insert/change the roll, and then rotate it back to an unaligned position to retain the roll. What I don't like is that the spring force is not exactly easy to overcome by hand.

    I'm hoping someone out there with a different perspective could point out an application which has already solved this, or maybe someone has a new tip or idea.

    Thanks for your input.

  2. #2
    Technical Fellow jboggs's Avatar
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    I'm completely lost. Post a picture or sketch.

  3. #3
    Senior Engineer
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  4. #4
    Lead Engineer RWOLFEJR's Avatar
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    If you have access to an old "Sundstrand Rigidmil" Rise & Fall milling machine, you might want to take a look at their quick change gear set-up for changing cutter speeds and table feed speeds. Your shaft would need to be able to extend beyond the roller you want to change. Beyond the roller there'd be a radial groove in the shaft. A collar slips over the shaft. That collar has a slot cut through to the center hole and houses a spring loaded lever that drops into the shaft groove. The design isn't intended for a heavy axial load but would handle a good bit depending on thickness and engagement etc.. There would also need to be some clearance and that would allow your roller to float a bit I suppose. Very simple to operate though...

    Similarly... And again if the shaft can extend beyond your roll and you can tolerate some slight end play... You might be able to utilize a system similar to a quick disconnect coupling for air or hydraulics. I'd expect that design to be able to handle more axial load since the balls become captured in the outer sleeve.

  5. #5
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    Thanks for the tip, I'll investigate this milling machine. I have no initial problems with extending the shaft out past the rollers. My problem is that the shaft is stationary and only the gear and roller are turning. If I want to avoid friction between the retainer and the roll, then I have to anchor my roll retainer into the gear somehow. My current design is with snap fits which are blocked once a bearing is pressed into place. I'm looking at using steel gear teeth with a nylon carrier and retainer. This design is essentially what Miller and Lincoln (welding) use in their carrier gears.

    I have studied all the quick disconnects I could get my hands on. They are a good start, but I don't want the balls to be racing around a stationary shaft.

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