AUTOMATA - "DiggerBot" Pt.6

Looks like I'm finally making some progress on this project. I have to say, this week was very challenging to keep my enthusiasm up. Lots of technical issues arose...but once I figured out how to work around them, my momentum picked up again. So...what did I get done since last time?

First off, I managed to assemble most of the parts for the digging arms. Now they're ready to be attached, once I get farther along on the other bits.

Here's where things started to bog down...making some gears. I drew up some plans on the computer, spray-mounted them to a 2x4, then cut them out on the band saw (one tiny tooth at a time). I tried some small triangular teeth first...took quite a while to do. But I soon found out that precision measuring and cutting are really crucial...not my strong points.

After failing at different variations, I finally found a website that had a little gizmo on it that lets you custom design patterns for gears. The larger teeth seemed like it would work better. Also, I decided not to make the gears so wide (from the 2x4 width) and used some half-inch hardwood board.

Here's the final version, and a little "gear box" that holds it all together. I've added the circular attachments where the digging arms will go 'round and 'round. The smaller gear at the bottom has the axle going through it that will be part of the hand-crank mechanism.

I then constructed some "cams" that will rotate on the axle, and push a "paddle/lever" up and down. This is what will cause the DiggerBot's mouth to open and close (by pushing a dowel rod to be added later). I shortened the paddle a bit from what you see below.

Finally, I made the "tank tracks" shapes that supports the gear-box. I will do a lot more detailing on those later...just wanted to get the main structure built. I'm still having some problems with the gears hanging up a bit, when I crank the handle. Hopefully, I'll be able to adjust some things later to fix that.
Okay...that's it for now...my head hurts from too much thinking this week!

SKETCHBOOK - "Renaissance Festival"

Had a lot of fun today at the Kansas City Ren-Fest! Took my daughter, Courtney, and her boyfriend, Andrew. The weather was gorgeous (although a little on the windy side). The last time I had gone out there was almost 30 years ago. They've really expanded it, and I was quite impressed. Instead of a camera, I decided to take my sketchbook along. After about 5 hours out there, I was surprised at how few drawings I ended up with. The costumes were great...but hard to sketch, because the folks were on the move most of the time. Just so many interesting things to look at.

Above is the back side of the main entrance...minus all the throngs of people as they came through the gates. Below... a pirate with a mechanical fake monkey on his shoulder.

Next... a bald, rotund fire-eater, in a cute little kilt...well...a rather large kilt, actually.
Here's another bald guy...this time a very tall, hairy juggler who was terrible at juggling, but hilarious with the comedy.

Finally...a couple of gentlemen playing duets on very long trumpets.
All in all...a terrific day. Will have to go again next year and draw some more!

AUTOMATA - "DiggerBot" Pt.5

Well, there's not much to show this week, except a messy workbench. But I do have some sketches of "problem solving". There were design issues that I had not yet figured out, so I needed to do some thinking on paper before I spent more efforts in wood.

One of the things I decided to add to the movements was the DiggerBot's mouth opening and closing. I had considered using a string or wire, which would pull on a hinge...but ended up with a simpler idea. The weight of the head will press down to keep the mouth closed. But a dowel in the neck will be pushed upwards by a lever, and gravity will pull the jaw open, as the head goes up.

I had cut out a more organic shape for the larger support arm. Originally the flat side was on the left, like an "L" (see sketch above). But I looked at modern diggers, and flipping the "L" was more like today's style. I had also made a circular end-piece for the lower arm. I now prefer the way I did the upper arm, so I'll have to modify them.

Once I had flipped the "L" shape, I was wondering about some other embellishments. On a modern digger, there are hydraulic arms that push and pull the main arm. Mine will be just for looks, since the support arm will be glued stationary.

Next, I just started sketching some variations on proportions and design. As I was working on some of the bits and pieces, my original prototype model started malfunctioning a bit. The earlier "belt drive" began to slip some, and the cranking motion wasn't working consistently. So I got a little concerned that my final version would have "issues". So I began to consider a gear driven mechanism. It seemed like it would be sturdier, and more dependable. I also spent a little time figuring out the cam-driven lever that would make the head go up and down.

It didn't take long before I was again handicapped by my lack of engineering skills. So I started sketching around with how I'm gonna make these wooden gears. Luckily, YouTube.com has some demos from woodworkers to give me some help.


So this last page has the basic gear-drive in place. I also thought that I should flip the triangular "tank tracks" around, more like early World War I versions. This approach would let me hide a second gear underneath, which would now become the axle used for the crank handle. The early model had a gear-box underneath...this way I can let the DiggerBot rest on a single base of wood.
That's it for this time...hopefully I'll make some progress on the construction next week. (I have to be honest here...this is moving slower than I want, and is not as much "fun" at this stage. I know I'll enjoy painting this guy...but that's a long way off. )