While this has nothing to do with the design of overhead cranes (well, maybe not), this story is something that a young machine designer should find helpful.
When I was starting out my engineering career nearly 50 years ago (I was working as a machine designer for a multinational corporation that manufactured capital machinery for the food and chemical processing industries), one of my early assignments was to adapt a new style conveyor to an existing oven used to bake bread (now these were for very large automated commercial bakeries). Anyway, I jumped right in as this was going to my chance to show-off to my management what I was capable of. Now it was not a really complicated project as the basic conveyor design already existed just that it had not been used for the feed and discharge conveyors of this particular oven model. One thing I noticed immediately was that it appeared that the drive-train combination of motor and gearbox was way oversized so I saw this as my chance to not only get the design right, but to reduce the cost as well. So using all of my newly acquired engineering skills I did the power calculations and looked at alternative motor/gearbox combinations and came up a much less expensive set-up. I replaced the existing 1 1/2hp, 1200 rpm motor with a 1/2hp, 1800rpm motor along with the appropriate reduction in the gearbox size, chain drive and sprockets, etc. Well, when I submitted this proposed redesign to my boss he asked that I go with him to the shop where there happened to be in production an oven similar to the one that this conveyor would be incorporated into. As he pointed out certain aspects of the machine he kept noting the electric motors being used and the size of the chain drives for the various parts of the machine, including the feed and discharge conveyors, which of course were still of the old existing design. And about that time he further pointed out that every single electrical motor used in this oven (except for the exhaust fans as they were special high-speed, low-torque motors) were 1 1/2hp, 1200rpm, flange-mounted, with the junction box on the right side of the housing and the chain drives were all 5/8 inch pitch. And the reason for this: So that our customers would only have to keep in their inventory of spare parts for this oven ONLY one electric motor and one stock of roller chain and links, ones that could replace any of the half-dozen or so motor/drive chains that were used for the mechanical drive aspects of the oven's machinery. BTW, this is exactly along the lines of the story related here by
zeusfaber ;-)
These are the sorts of lesson that are overlooked in engineering school when we were taking our machinery design classes. It's also the sort of thing that you probably would never even read about (except perhaps in a forum like Eng-Tips). So, as suggested before, you'll need to get some real first-hand knowledge before you could consider yourself qualified for a job like this, so if you continue with this effort, be humble when you talk to your potential new employer and tell them that you're eager to learn the tricks of the trade as well as bringing your current, if still green, talents to the job.
And for the record, while I only spent 14 years of my nearly 50 year engineering career working as a machine designer, they were very rewarding for it was a chance to see your own ideas fleshed-out in iron and steel, a permanence that many people's ideas will never enjoy.
John R. Baker, P.E. (ret)
EX-Product 'Evangelist'
Irvine, CA
Siemens PLM:
UG/NX Museum:
The secret of life is not finding someone to live with
It's finding someone you can't live without
