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  1. bertfourie

    Cylinders in series to rotate a load

    Jacc, the normal maximum pressure required to generate the force to overcome the load resistance is around 2400psi. A chain requires around 5% of the working load as tension on the slack side, which works to roughly 120psi, which is in the range of a counterbalance valve from my understanding.
  2. bertfourie

    Cylinders in series to rotate a load

    zeusfaber, right, I got you. I was imagining the oil between the two pistons working like a "rod connection", but I can see the issue with that. It is not like that at all, only the pressure in the gland sides does the work, and so really, leakage over the seals would not be a problem, unless it...
  3. bertfourie

    Cylinders in series to rotate a load

    Jacc, thanks for that! Appreciate your thoughts. The device is used to rotate a clamped pipe through 180 degrees. The CFG of the pipe will not always be central, so the loading direction on the chain rotator will switch during the turn. It is slow-rotating. I basically agree with your circuit, I...
  4. bertfourie

    Cylinders in series to rotate a load

    Thanks Brian, agreed, I am using a 1 3/4 duplex chain and the shaft is supported on substantial tapered roller bearings, but I shall review again in light of your comment. Thanks!
  5. bertfourie

    Cylinders in series to rotate a load

    Hi Ted, sorry, it is a term I invented - I think this is like having a through-rod cylinder but the through-rod has a gap in it with two pistons and oil in between. Assume the pressure is applied to the rod end of the first cylinder and it is pulling on the sprocket. The chain is now also...
  6. bertfourie

    Cylinders in series to rotate a load

    Jacc, I now saw the pic you attached, yes, that is exactly it! What is the application in the photo?
  7. bertfourie

    Cylinders in series to rotate a load

    Thanks Jacc, yes I was thinking the same. This application is the same as having one cylinder, except that the rod effectively has an "oil gap", and the issue is how to deal with leakage past the two pistons on either end of the oil gap. I was also thinking of some form of flow resistance...
  8. bertfourie

    Cylinders in series to rotate a load

    What information are you missing Dave?
  9. bertfourie

    Cylinders in series to rotate a load

    My question is not for a design proposal, it is purely whether or not the hydraulics application I describe is feasible.
  10. bertfourie

    Cylinders in series to rotate a load

    Good suggestion, I did look at that but the size I need is about double the length of the space I have. I also considered slewing drives but they cannot do the radial loads. That is why I opted for a sprocket and transmission chain - compact in both directions and I can use a bearing setup to...
  11. bertfourie

    Cylinders in series to rotate a load

    I need to rotate a load suspended on a shaft. I would like to do so via a chain over a sprocket to turn the shaft. Due to space restraint, I would like to use a cylinder(s) to move the chain and translate linear motion into rotation. I considered a through rod cylinder to be able to rotate in...
  12. bertfourie

    State of the Art - Hold down bolt, chair design

    Several studies have shown that the standard chair design creates a stress concentration, which may lead to tank failure in an earthquake situation. I was wondering what the latest design evolution look like? What is current best practice?

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