Insane Hydraulics
Bold and audacious blog about fluid power
Most if not all truck cranes rely on hydraulics to operate, and an army of careless owners and operators make sure that these machines visit "hydraulic businesses" regularly, either to acquire parts or to troubleshoot malfunctions.
Since I deal with hydraulics, I, naturally, have had my share of "crane related interventions", and I can say that most of the times these machines aren't that much of a troubleshooting challenge, but they do possess a rather dangerous quality, common to many hydraulic systems, which is often forgotten about, even when it is practically staring in your face, like in the case of truck cranes.
Most likely the last sentence didn't make much sense to you, so I want to try and clarify my point with an example from my practice:
One sunny day I was diagnosing a hydraulic problem of a truck-mounted crane - one of the outriggers wouldn't come down. The problem was quickly identified and fixed, and I was cheerfully extending and retracting the outriggers to show the satisfied client that the puzzle was solved and how great a hydraulic technician I was to have unraveled the mystery on the spot! You can't argue that watching a hydraulic machine readily respond to your commands is a thrilling experience, and I was beginning to get carried away... when, regrettably and rather unexpectedly, my enthusiastic performance was interrupted by a squeaking sound of something being crushed as I lowered one of the outriggers from the other side of the truck (the one I couldn't see)...
"Oops!" -said I, and rushed to see what it was, mumbling (with my fingers crossed)
"Please don't let it be the dog...."
"Please don't let it be the dog...."
"Please don't let it be the dog...."
The "it" turned out to be my "better" toolbox. The poor thing got deformed, but, luckily, no animals or human beings got hurt. The strangest thing, however, was something that happened a week later to a guy from our workshop (the one who was laughing the most when he saw the pancake the toolbox had become), who lowered an outrigger of an alike crane smack dab in the middle of a brand new data logger, crushing it to dust... Well, he did beat me at the crushing game, I give him that!
My point is - when you troubleshoot a piece of hydraulic equipment, you will have to operate it at some point, and since the primary purpose of oil hydraulics is power transmission over distance, an actuator can be quite a long way away from where you are controlling it - like the outrigger on the other side of the truck - which is extremely dangerous!
So, please, please, don't forget to check if the "invisible" machine's movement you are about to start is safe to be made.
I guess with the outriggers, one might as well say: "Watch where you step!!!"