As mentioned in an earlier article, one of the three N.F.P.A. cylinder mounting classes is fixed non-centerline mounts. These mounts include side lug (MS2), end lug (MS7), side flush (MS4), and foot bracket (MS1). In applications where a fixed non-centerline mount is required, Sheffer strongly recommends employing a thrust key plate or dowel pinning the cylinder depending upon the specific mount. This is done to minimize shear loads on the mounting bolts as well as providing a means of cylinder alignment.

In 1962, E.F. Houghton Co. published A Handbook On Hydraulic and Pneumatic Packings for the fluid power industry. In the opening chapter there is an illustration of a “typical animal hide” which depicted the best parts of the hide that could be fabricated into leather “U” cups, “V” rings, and gaskets to seal fluid power cylinders.

It is Halloween night and the goblins are out begging for candy, I hear the door bell and head towards the door to see what is going to be greeting me this time.  After they leave I check my display outside where I have fake blood pumping down a fake corpse lying in a coffin.  The pump spatters a little because some of the fake blood evaporated. As I am adding more 'blood' to my pump I start thinking about work and how a hydraulic cylinder will act if not properly set up...

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.