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Recent content by LaurenceSachs

  1. LaurenceSachs

    Gerotor Motor Design

    I have looked at radial piston motors too. For that torque we would need a big unit. The whole device has to weigh less than 22kg...
  2. LaurenceSachs

    Gerotor Motor Design

    I have found that the torque requirement is rather high at 15kNm. A gerotor will not be viable for this as it will have to be too big. Any other suggestions?
  3. LaurenceSachs

    Gerotor Motor Design

    Hello Gents! Thanks for all of your help on many other topics! Next question: I am looking at novel ways to incorporate rotation onto a shaft using water under pressure. I have been interested in designing a gerotor motor that is energised by water at about 16MPa and with as little flow as...
  4. LaurenceSachs

    Part Concept Selection and Decision Process

    Yep it is a lot of extra work, I think I am just cautious of forgetting to take something into account... Thanks
  5. LaurenceSachs

    Vibration Damping on Old Percussion Drill

    Hi Ted, Thanks, yes I am looking at a spring mount for the handle. I just need to work out how to design the spring correctly.. L
  6. LaurenceSachs

    Part Concept Selection and Decision Process

    Hi there, Thanks for the input. Any more suggestions or spreadsheets that you use? Attached, See the matrix I may use in the future:http://files.engineering.com/getfile.aspx?folder=8b34b391-30ea-4821-919c-c658227f482d&file=Book2.xlsx
  7. LaurenceSachs

    Part Concept Selection and Decision Process

    Hi, Well yes, part of the problem is that weighing each of the criteria like reliability, corrosion etc are all user inputs and therefore manipulated. Also when scoring each concept, the scores are related to the designers existing knowledge or lack thereof. It is also possible that the...
  8. LaurenceSachs

    Part Concept Selection and Decision Process

    Hi there, I trust you all are having a good start to the new year! As a design engineer, I continuously have to look at new ways of designing components or products. I obviously have to take cost, weight, material, corrosion, reliability, performance etc. into account. I am familiar with...
  9. LaurenceSachs

    Hydraulic vs pneumatic piston/cylinder design

    Hi, Yes the piston has to push the water in the opposing chambers away, its complex. This is an existing device.
  10. LaurenceSachs

    Hydraulic vs pneumatic piston/cylinder design

    Hi Ted, There is another chamber further down the piston rod that is only pressurized when the piston is fully forward. This is because of the valve that is opened by the piston in the full forward position. What about the friction and counteractive forces that act against the piston? how do I...
  11. LaurenceSachs

    Hydraulic vs pneumatic piston/cylinder design

    Are we talking the same concept as Rotameters (variable area meter)? http://en.wikipedia.org/wiki/Rotameter
  12. LaurenceSachs

    Hydraulic vs pneumatic piston/cylinder design

    Ah yes, One can use the continuity equation in bernoulli's to get the pressure difference across the piston. If you have the flow rate, which I have! F=P.A so we can work out the force being exerted on the piston. Am I on the right track? Laurence
  13. LaurenceSachs

    Hydraulic vs pneumatic piston/cylinder design

    I think I have the mass flow rate around the piston but I don't have the pressure difference, its not easy to measure. Is there a law that states that the piston will move the same speed as the water in that cavity? I can't see that being true?? I do not know how the piston is continuing to...
  14. LaurenceSachs

    Hydraulic vs pneumatic piston/cylinder design

    Israelkk, Tell me, how do you calculate the pressure once you know the mass flow rate passing the piston? And what do you do then? Laurence
  15. LaurenceSachs

    Hydraulic vs pneumatic piston/cylinder design

    Thanks Ted, The hydraulic drill in question has a piston stroke of just under two inches however the pressurised section as per drawing is only about half an inch. Do you know of any reference material I can have a look at that will fully explain the hydraulic workings? Who don't hydraulic...

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