Overhead Crane – II

Project 03082015
SWRenderI tossed in various models into one mesh calling it Project 03082015 .. 08 March 2015. In this went two carriages, the bearing blocks, Gears, Pullies and the upper and lower crane blocks. In addition I added my Welch-Wise-Peco Point Guards for one Right-Hand and three Left-Hand switches.
blocksRenderA closer look at the crane blocks. I included both an upper and lower block. I only need one set but I added an extra one because .. you can never have too few crane blocks!
trolley2-800Working on the Trolley. I .. think .. that is the correct term. This is quite small relatively .. riding on Evergreen #276 3/16″ I-Beam. The Flange I show as .09″ wide lists by Evergreen as .093″. I added detail to the hanging plates that should add interest. During this design I have to keep withing the constraints of FUD .. minimum wall thickness of .3mm mostly. With the upper portion of the trolley completed i design I will turn to the lower end where the upper crane block attaches.
trolley3-800Using the ‘power’ of virtual modeling I can align the trolley and upper crane block .. and a couple of things become clear very quickly.

First .. the pivot/pin location on the bottom of the plates is too high for the block swivel. This is a problem that came about because the original I used as a guide had a pin that dropped in the center between the plates. This may have been to keep the pin from sliding out .. (insert shrug). Wanting to use a straight pin for ease of assembly with the model I would modify the design and drop that pin location down on the plates enough to clear the bottom of the I-Beam with the block swivel.

Second .. the small pin ‘end’ on the outside of the plate .. I got too ‘fancy’ with it .. it is too small for one thing. I’ll fix that too.

trolley4-800I simply cut the end of the plate off and dropped it down enough that the block will clear the I-Beam. I added a bit of cross-bracing and filled in the area that the pin would go. Next would be to fill in the space between the block swivel and the plates.
trolley5-800.. and the results of all of that with the trolley on the I-Beam and the upper block swinging off the trolley block pin (yes .. I made that up!). Next question for me is .. how do you move it along the I-beam? I’ve used smaller such cranes where you simply tug on the chain hanging from the block to move the trolley. Rope could also attach up toward the top of the trolley you could pull. Will have to research that a bit.
trolley6-800… and the Trolley ready to be exported as a 3D mesh. To do that .. as in all 3D prints a lot of attention is paid to removing all internal polygons. In effect what you see in the picture is a shell without any internal structure. This is what Shapeways .. “likes”.

Just for a size comparison .. that pin is .8mm dia. That’s about 0.032″ dia .. or 1-1/2″ dia full size (in O scale)

Carriage Wheels
wheelsOne of the things I had *meant* to do (always a danger when I am working) was create the carriage wheels for 3D printing. This was because the suckers are just so darn small!! Note that they are only 0.167″ in dia. Trying to cut the rail-groove and drill the axle hole .. *meh* … the heck with that! One of the problems though is .. well .. the suckers are just so darn small!!.

Somewhere on the Shapeways site I saw where they said the minimum size of a model is 5 x 5 x 5 mm. Not sure if that is all three axes .. or two .. I mean .. can it be 5 x 5 mm. and ‘itty bitty’ in the other dimension? Donno .. so I stick small objects on a sprue so they meet that minimum .. and it works.

I haven’t ‘finished’ these yet – as they don’t meet that minimum except the length. I don’t show it but outside one wheel to the other is only 4.7mm. The 4.247mm dia of a wheel (also the height) is also below the 5mm minimum. I figure this COULD pass the minimums even though it is ‘correct’ for only one dimension .. it is ‘close’. I can make the sprue bit a little wider to fix the width and I would be ‘good’ in two dimensions. To be ‘safe’ I would just mirror the wheel array vertically and connect with sprues. That would give me 8 wheels .. come to think of it .. I have that OTHER crane I need for my pier …

Blocks Ver 2
blocksVer2-800I made a few additions (rather than changes) to the block with my morning coffee (blocks and coffee?). I added a becket to the top/anchor block .. and spacers to both blocks around the bolt to keep the plates aligned. I think this is pretty much “good to go”.

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