Cylinder Mounting & Column Loading

“I need 100,000 pounds of force on a 120” stroke with a 2” diameter piston rod and clevis mount.” A click and then there is no one on the other end of the phone. 

Cylinders convert a fluid pressure into a mechanical force.  The input fluid pressure acts on the surface area of the cylinders piston displacing it to create a linear movement of the piston rod.

When installed with proper alignment, fluid power cylinders will provide the smooth trouble free performance for which they were intended.  Unfortunately, perfect alignment is extremely difficult, if not next to impossible to achieve. During cylinder operation, any misalignment can impose an eccentric force on the piston rod known as “side loading”.

Well, if that isn't a loaded question. Over the years more people than you would expect have proposed this puzzle and while there may be no single answer to this complex query, there are many variables to consider in attempting to answer it -- so let's start there.

You know that sinking feeling when you take the first bite of a much needed lunch, the phone rings and you answer to hear the words "We have a problem; it’s a new installation and the tube seals have blown!" With thoughts of catching a snack later in the day, you attend the scene of the crime...

Any piece of equipment operates best when it is used regularly within normal guidelines.

Take for example a classic car; it ran perfectly when you put it away last fall, but something happened during the long winter.

In our experience, the call for more than one mounting feature on a cylinder is by no means a rare event.

We won’t say that all mounts can be combined; as clearly there are some features which would just interfere with each other. For instance, a Front Head (FHF) and a Side Lug (SL) cannot coexist on the same end of a cylinder. What is possible, however, is to have an FHF (Head) mount combined with a Side Lug at the Cap; if that serves a useful design purpose for you.

Ever thought that you have had to go a long way around a design problem to mount a particular component? Here's a hint that might possibly be a ‘quick-fix’ and a help if you're finding yourself in a similar situation.

Sheffer fits tie rod supports to long stroke cylinders to stop the tie rods from twanging like an out of tune banjo - and the design feature does a wonderful job of achieving that aim.

Boosters or intensifiers are used to create a high pressure output from a low pressure input. Much like how an electrical transformer works by trading current for voltage, a hydraulic booster transforms a larger volume of low pressure fluid into a smaller volume at a higher pressure.

Those engineers in the know; will be all too familiar with the possibility of bacterial growth within the relatively cozy environment of a hydraulic system. So these thoughts are probably only going to be of interest to the tiny minority of system designers and maintenance engineers who are dealing with a certain type of installation.