Engines > Your Own Design
Ohio Locomotive Crane
crueby:
With the Ransome tree feller model finally sorted out, its time to move on to my next big project. And this one will be pretty large!
Last spring when I was up at the first event of the year at the Maine Forest And Logging Museum, driving the steam and gas Lombard machines around the grounds, one of the other volunteers and I were talking about my model projects while driving the steamer around the road loop. Steve mentioned that he had a stack of original catalogs for steam shovels and such that he had collected as a kid. That got my attention! When he said he would send them to me to keep, I nearly drove the steamer into a tree!
A week or so later a package arrived in the mail from Alaska (where he lives now - a REALLY long commute to the museum) with a bunch of vintage catalogs. :whoohoo:
One of them is from the Ohio Locomotive Crane Company of Bucyrus Ohio, showing details of their line of rail mounted cranes. These are general purpose cranes in the 15 to 30 ton range, not the more massive wrecking cranes with capacities up in the 200 ton (and more) range. These cranes were steam powered, self propelled, and could be fitted with either lifting hooks, clamshell buckets, or drag line buckets. The catalog has lots of detail photos of the component parts:
as well as a fold out blueprint in the back giving profile/plan/arrangement views. An amazing resource. Naturally, it got me planning and plotting for a model of one. Most of the drawings in the catalog are for the 20 ton version, so that is what I'm going to build.
About 3 weeks ago I started the CAD drawing of the machine, at full scale, of the 20 ton crane. Here are a couple renders of the CAD model:
When the CAD model at full size was complete, I took some key measurements from it (wheel size, piston size, gears, frames, etc) and put them in a spreadsheet to play around with different scale factors to decide what size to make the model. I wanted it large enough to have the power to lift heavy things (like a weeks supply of beer for the shop elves), but small enough so the parts would be practical on my small Sherline lathe/mill plus the fasteners would not be too tiny - I like most to be in the 2-56 to 4-40 range. What I settled on was 1:11 scale, which is an oddball scale but so what? I may not make the boiler functional, since I rarely steam up any of the ones I've made on other models, normally just running them on compressed air inside the house and the occasional show.
This crane has some challenging features that took some time to work out. One is the system of clutches that operate everything. On all but the 30 ton version of the crane, they used just one 10"x10" two cylinder engine to power everything, and that engine only runs in one direction, no reverse gear on it. All the other shafts are driven by a set of gears from the crankshaft, and cone clutches activate each function. The catalog describes how the cone clutches had bronze cones, which give some slippage when engaging, but they say this was intentional to eliminate hard shocks as clutches engaged under heavy loads. The lifting drums (one for the main hoist, second for use with the second line on a clamshell bucket or dragline), each have a single clutch, so the engine has to run in the direction that turns the drums in the proper direction for hoisting. Lowering was done with brake bands on the drums. The other shafts, for slewing the crane, driving the wheels, and tilting the boom, all have pairs of clutches around a set of bevel gears, as shown in the next picture:
The clutches are pointed at by the red arrows. The cups are directly attached to the smaller bevel gears, while the cones inside are keyed to the shaft and can slide back and forth. There are cam pairs fixed to arms, blue arrows, to engage/disengage the clutches. The cups and small bevel gears can freewheel on the shaft when the clutch is disengaged. With the shaft always spinning in one direction, the drive on the large bevel gear (green arrow) only happens when one clutch is engaged. Since the small bevel gears are on opposite sides of the large gear, if one clutch is engaged, the vertical shaft will be driven in one direction, and when the other clutch is engaged, it will spin in the opposite direction. When neither clutch is engaged, the vertical shaft is not driven at all. The levers and cams are connected to a single lever, so pulling the lever back engages one clutch, pushing the lever forward engages the other, and leaving it in the middle disengages both. Quite clever, and makes one lever control everything for that function.
There is one shaft and set of clutches for slewing the crane turntable, one for tilting the boom, and one for driving the wheels to move the entire machine on the rails. The hoist drum shaft has one clutch for each drum. All that means making eight clutches.
The other big challenge is the large ring gear that sits on top of the carbody frame holding the wheels. It is a little over 8" in diameter, and has internal teeth so I can't use my normal gear cutting setup for it, since the mill headstock/motor wont fit inside the gear. That means exploring a number of other alternatives:
* Buying the internal tooth ring gear
* Changing the design to use a slightly smaller external tooth ring gear
* Making the ring gear in a number of sections (8 or 10 probably) that fit together and bolt down to form the ring
* 3D printing the ring gear in something like PETG
* Having the gear 3D printed in metal by an external service
* Making an internal gear cutter holder, seen someone else did that on another thread hereEach option has its issues. Buying one would be quite expensive, assuming I could find one the proper size and tooth count. Using a smaller external gear would be the simplest but not true to the original, though with the turntable in place it wont be visible, but my shop elves would blab it around so everyone would know. Making the gear in sections is possible, though getting them all to fit up just right would be a tricky thing. Printing the gear myself in plastic would be possible, though I'm not confident that it would hold up to the load of such a heavy model. I could have it printed in metal, like I did with the excavator bucket a few months ago, but taking measurements of that and comparing to the CAD model show that while large dimensions are within a few thou, smaller wall thicknesses are out by 15 to 25 thou, making me wonder how well it would function. Making an internal gear cutter rig would be pretty cool, though working out how to hold it on my machine is tricky, plus the gear blank would need a wide standoff to hold it and give the cutter clearance. I did some searching on the forum, but have not found that thread yet - anyone remember where it is?
So, the slewing ring gear needs to be worked out. The clutches I think I have a good handle on. There will be lots of spur and bevel gears to cut. The main boom will be an interesting task too, getting a LOT of angle stock milled or soldered up and riveted together - the boom is over thre feet long at this size. Also, will need to make a LOT of I beam stock for all the long lengthwise and short cross beams in the carbody. Should be able to make them the same way I did on the Marion steam shovel build, with a series of small jigs to hold the webs together for soldering. Lots of challenges, but thats the fun part!
Where is it at right now? The CAD model is complete, and I've generated all the 2D plan sheets and printed them out. As usual, there will be tweaks along the way to add missing dimensions and whatnot. I'll start at the bottom and work my way up. I have a 6' length of rail section to use as the track display base - section was left over from my Kozo New Shay model, which sits on a curved trestle section of track. Just need to make up the wood ties to make the track section. The wheels are quite large, with a 3-1/4" OD, and there are eight of them to make. I have 3-1/2" diameter bars of 1144 stressproof steel and 360 brass, either would work. The steel would be perfect for appearance, though turning that many large wheels would be pushing my little lathe pretty hard. The brass is lots easier to turn, but not really the right appearance for a painted model. I have not decided what the finish will be on the model - painted, or bare metal. If painted, I could nickel plate the brass wheels. If not painted, I could just leave them the brass - the center frame for the turntable will likely be milled out of brass too. The boom and truck frames would likely be made from tool steel strips. Gears will be brass. :thinking: Whatever they are made from, I am thinking that I'll use small taper locks to hold the wheels to the axles, the flanges hidden either on the back sides of the wheels, or behind the oil boxes on the outsides.
Should be a fun build! Will get started with the track, then move on to the wheels. Will be a slightly slow start, with the new room addition about to start construction, I've been moving a lot of things in the basement to clear access for the crawlspace opening plus in the garage to give the crews access through to the back door, and need to move things off the walls and away from the openings in the existing room that the addition will build off of. All going smooth, though my back gave me a warning twinge to slow down yesterday when I was hooking up the hose outside to clean off the garage floor. One too many bend over movements in one day! Getting much better now, just a muscle pull, I'm glad it fired a warning shot before going out completely! The track work is very light, it will give the back a rest before I have to haul the big bar for the wheels upstairs to the bandsaw to cut the stack of giant hockey pucks for the wheel blanks.
:cheers: :cheers:
cnr6400:
:ThumbsUp: :ThumbsUp: :ThumbsUp: :popcorn: :popcorn: :popcorn: This is going to be a good one! I'll get the screamin Jimmy dump truck ready to send an 8 ton load of premium white popcorn. Still haven'[t fixed the missing exhaust stack, so your shop elves will hear it coming.
Hope your back settles down and feels better. :cheers:
Kim:
This sounds like another very exciting build, Chris! I can't wait to follow along with your progress on this next adventure! :popcorn: :popcorn:
Sorry to hear about your back. Hope it's all back to normal soon.
And good luck with the addition. I expect a tour of your new museum room when it's complete :Lol:
Kim
crueby:
The back is improving quickly - hot shower last night and a good nights sleep worked wonders (as a friend of mine likes to say, Tincture Of Time is a good cure sometimes).
Will post pics on the new room as it progresses, they should start construction within the next 2 or 3 weeks. It will give a lot more space to display the models, and I'll run air lines around it to run them.
After a suggestion from Jeff, I looked into EDM and CNC services online. Prices vary all over, but I've found places that will machine the internal ring gear set (ring gear plus the matching spur gear) for under $100, out of aluminum or steel, which is a lot less than I had expected. Not bad for a 9 inch internal gear! Way to big to do on my machines in one piece.
Admiral_dk:
I have seen a number of Post WWII Steam Rail-Road Cranes in former Eastern European Museums, in different conditions - but this one precedes them by - what - 30-40 years ...?
Very much looking forward to follow this one :LittleAngel:
Per :popcorn: :cheers:
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