Step-up hydraulic cylinder?
Step-up hydraulic cylinder?
(OP)
Hello:
Today I came across a website for a 'step-up hydraulic cylinder'. Apparently it has a high-speed, low force mode and then when it encounters resistance it switches to a low-speed, high force mode. I'm assuming that it must work by somehow altering the active pressure area of the piston, but how would this work? Any input is appreciated.
The website is:
http://www.simson.ch/English/Hydraulic_Cylinders.html
Cheers,
Denande
Today I came across a website for a 'step-up hydraulic cylinder'. Apparently it has a high-speed, low force mode and then when it encounters resistance it switches to a low-speed, high force mode. I'm assuming that it must work by somehow altering the active pressure area of the piston, but how would this work? Any input is appreciated.
The website is:
http://www.simson.ch/English/Hydraulic_Cylinders.html
Cheers,
Denande





RE: Step-up hydraulic cylinder?
Alex
RE: Step-up hydraulic cylinder?
After the rod contacts something substantial and the pressure rises you then switch to the "normal" plumbing for your high force slow speed.
This works well on hydraulics but not very well with air.
Barry1961
RE: Step-up hydraulic cylinder?
Isn't the pressure in the cylinder constant? If so, what determines when the secondary (outer I guess) cylinder is activated?
Cheers,
Denande
RE: Step-up hydraulic cylinder?
RE: Step-up hydraulic cylinder?
Dual pressure pumps are common for applications like this but they do not reduce the volume like advertised on the web page. I think they are just plumbing the ports together for a quick extend. They could be using a flow meter, pressure switch, load cell, linear transducer, motor current sensor or other device to tell when the rod hits something.
Barry1961
RE: Step-up hydraulic cylinder?
Think what you have found is a HYD cylinder that has two sizes of cylinders in line with one (Small bore) that will telescope inside the other (large bore) to drive the rod.
No check valves are needed. If the resistance is low the small bore is driven fast. If the resistance is high the large bore is driven slower, yet develops higher pressure (all using the same pump). Some farm tractors have used this concept for loaders. The difference in the surface area of the pistons determines the force developed.
To visualize this, think of the larger bore cylinder as a helper for the small, yet it draws oil from the same source and thus the travel is slower
RE: Step-up hydraulic cylinder?
Moreover, the control system can be simplified due to the integrated control valves.
This would indicate that it works at least similar to Barry1961's supposition. Note the plumbing connecting the ports. We make machines using the high/low, dual pump concept. This cylinder looks interesting for us.
RE: Step-up hydraulic cylinder?
http://www.multicyl.com/multicyl.htm
http://www.tox-de.com/e/products/powerpackage/index.htm
Bud Trinkel
www.fluidpower1.us
Bud Trinkel CFPE
HYDRA-PNEU CONSULTING, INC.
fluidpower1 @ hotmail.com
http://www.fluidpower1.us
RE: Step-up hydraulic cylinder?
I just looked at the website you posted and I may be wrong in total Ha Ha. Sorry for the confusion. That type of operating method must be more complex being they have a patent.