Jack Screw Actuator for Whitewater Park
Jack Screw Actuator for Whitewater Park
(OP)
I am trying to design an obstacle for a whitewater park that I am working on. The obstacle is a swinging barn door type gate that is typically aligned with the current. The hinge pins are at the upstream side. At the downstream end I want to have an extender that is attatched to a vertical jack screw. The extender forms the hypotenuse-link between the top of the jack screw and the bottom of the barn gate.
So here is my question: The reason I am using a jack screw is that I want the gate to be adjustable by visitors to the park through a crank wheel. However, this arrangement puts a tremendous thrust load on the jack screw and I am worried about binding. Can I just oversize the jack screw or is this a bad design idea from the start? The total thrust load is approximately 13,000 lb force. Due to space availability the jack screw must remain vertical.
Scott
So here is my question: The reason I am using a jack screw is that I want the gate to be adjustable by visitors to the park through a crank wheel. However, this arrangement puts a tremendous thrust load on the jack screw and I am worried about binding. Can I just oversize the jack screw or is this a bad design idea from the start? The total thrust load is approximately 13,000 lb force. Due to space availability the jack screw must remain vertical.
Scott





RE: Jack Screw Actuator for Whitewater Park
We use products from both the following companies. We have changed several screws from the Acme Type to the Ballscrew Type. I don't know why as stated there have been not problems.
There is some very good information on these sites.
http://www.nookindustries.com/ball/BallCatalog.cfm
http://www.duffnorton.com/products/mech.aspx
RE: Jack Screw Actuator for Whitewater Park
Try to find a way to cheat!! Can you divert part of the water into a drum counterweight to raise the ramp?
Acme screws will not back drive. Acme screws are not very efficient and hard to turn the first few revolutions if left under load. Using high pressure grease and oversizing the srew will help the start in high load applications. Of course use high pressure grease.
Ballscrews will back drive and are very efficient. They are very good at high speed, high cycle applications. They also cost much more.
Barry1961
RE: Jack Screw Actuator for Whitewater Park
RE: Jack Screw Actuator for Whitewater Park
1. Use an oversized rod (oversized for the thrust load).
2. Use an internal stop tube around the rod that prevents the rod from fully extending. This means you must size the nominal length of the actuator for the desired stroke plus the stop tube length.
3. Do all the calculations for buckling, friction, bending, misalignment, etc.
RE: Jack Screw Actuator for Whitewater Park
RE: Jack Screw Actuator for Whitewater Park