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 Building / Mecha / 14713
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Subject: 
Re: Blue Bear (Frame Tech)
Newsgroups: 
lugnet.build.mecha
Date: 
Thu, 2 Nov 2006 08:41:16 GMT
Viewed: 
6793 times
  
In lugnet.build.mecha, Marco Tagliaferri wrote:
   In lugnet.announce.moc, Eric Sophie wrote:
   New Mecha

Blue Bear - 21 inches tall - built in 4 days.



-Snip-

  
I would appreciate if you documented the joints explicite. It is hard to see
how some of them work.

Please take some more detail pics of the frame. The frame is the highlight for
me.

-Snip-

Hello Marco, when I completed the main body components I took some pictures before I started to cover up the frame work. So you are/he/she/they/mini-fig is are in luck! I even optimized the photos and they are all around or under 150KB, yay you!

Click to view full gallery

See, I don’t even feel bad about posting this 177KB full size picture now. Ha ha. Just kidding, enjoy this pic I made.

Ok, anyway, on to the Joint Tech:




Let’s see here, yes the Blue Bear:



The head was the first part of the Mech that I built. I used a new Red LED Light Brick that has a TECHNIC push button similar to the MINDSTORMS Touch Sensor. The head is built around this part.

The neck joint is a ball and socket type, the ball joint is one of those 2L axle grip part and the socket is the clip with the inner rubber grippy dealy.



Just below the head connection, sits a pair of TECHNIC triangle plate worm gear boxes. These pair of worm gear drives are mounted right next to each other, so the component is a 4L in width. This controls the arm’s lift and raise, upper most shoulder function. The axle’s force passes through a u-joint that is bound by a horizontal pivot, this pivot agent is a 4x4 click turn table. (blue with black round 4x4 on top). Just like the Macro Bot and other Mecha Joint Tech I use. This time it was cool to use the two blue click turntables and see how small I could make it, plus add to the model’s flexibility.



The upper shoulder splay connection is just two ball joints, but they are the new types that you can pass an axle all the way through. This way you can build directly along side the clip and TECHNIC connections. The older original ball joints that can accept a 1L axle distance, protrude outside the 1 brick dimension of the clip’s width. Go buy a Toa Matoro #8732 to see what I mean, and FUT to .marketplace, lol. That set has the new ball joint. It is a great improvement and still works as a ball joint in the original clip system. The advantage of having the axle bore go through the whole ball joint, is in the ability to build in a more compact area and to lock or bind the ball joint to a clip by passing an axle through the ball joint just as you would a bushing or TECHNIC plate. Good part. = Improved Mecha

The doubling up of ball joints can be seen in the upper arm rotation. I used them as rotational friction components. So the lower arm can swing in and out, plus the axle that passes through the rotational pivot point, is supported by a blue TECHNIC plate turntable. So the lower arm won’t just separate during movement. I like those small compact turntables. They attach with 3/4 dark gray pins, directly to TECHNIC bricks.

Spine pivot and side to side bend

The elbow joint is connected to the NEW ball joint. ;)
Allowing the pivot component to be encased in a 4 wide area. The lower forearm rotation uses a set of old style black friction pins.



The hands were interesting for me. Hands are always tricky. I think we know as builders, so long as we keep an open mind and rely on creativity, we’ll always come up with new hands for mecha. That’s what we like to think. Ha, good luck!

BUT oh noooo, hands are hard! and forget about thumbs, lol!

Really, I think at least there is a finite amount of parts that are good for hands at a relative small scale. Though with Lego, that cannot be true! If we use creativity, even imagination we will always come up with new parts for hands. (ya I wish, its hard!) Alas, at the 6 to 18 inch range or so here or there, it sure is hard to make an original set of hands. Ask Master Gla!

For me I was glad to make a new pair of hands, even if they are strange looking. By strange I mean, they are just a tad to small in this case, and I think they are not bendy enough. Not bad for Pipe Wrenches I thought.

In some pictures I think the hands look to scale and in others, not.



The upper body can pivot side to side L/R and it can also bend B/F.

You can see the ball joints that work the side to side pivot of the upper body in the picture above. One really cool thing is that the side to side splay makes use of the channel that is found below the 4x4 click turntable.

When bending side to side, the spine and supporting connections actually pass within the channel below the click turntable that operate the shoulders. Both systems work together. In both shape and clearance.



The main spine pivot is controlled by a worm driven TECHNIC Throw Bot Gear Box. That gearbox is surrounded by bricks and then directly mounts to a TECHNIC plate turntable in the waist to provide upper body horizontal pan and tilt.

Two ball joints are stacked togther with clips to provide rotational friction for the waist’s upper body horizontal pan. These fit directly between the two hip joint worm gear drives.



The hip joint is composed of two TECHNIC triangle plate worm gear boxes. These drive two bricks with axle grips. So the legs can lift. Two ball joints with the rubberized insert clip sockets create the hip splay. These work really well and are strong. Key to the ability of the robot to stand. The draw back of this set up is a high sensitivity to axle twist on the hip joint worm drive. Since the robot is relying on two axles at the hips, coupled with the inherent instability of the z24 backlash worm drive component. This is countered by posing the model to torque its joints against each other, so the forces line up towards the center of the body, thereby cancelling out the inclination for the mech to want to lean forward or back.

Like placing one foot in front ahead of you and one foot back to brace yourself towards the vertical center of gravity of your body.

This takes place in the hips. The entire mech can shift its center of gravity by minute adjustments of the worm drives in tandem with other joints depending on how the mech is positioned.



The knees use a worm gear drive set up. The ball gears just transfer the motion to an easily accessible set of control knobs on the sides of the legs.

What’s neat about the knees to me is they use a seldom included worm gear set up incorporating TECHNIC quarter oval plates instead of triangle plates or other known single worm gear box elements.

There is a set of 2x2 click joints in the lower calves’s of the Blue Bear so the feet can angle and rotate.




The legs were not covered completely in the final build. I left parts of them open and “see through” to help aid in weight and in the visual sense to keep the flow of the legs light, since I felt they were getting a little wide due to the knee and hip components. The ankles feature the same type of worm gear set up as contained in the knees. The ankle’s side to side splay is assisted by frictional 3L pins to aid in the legs hip splay control.



I still wish I would have included a bending toe set up. That would have been great, maybe worth revisiting? I decided against it as the foot was getting big already, due to the way the ankle pivot and splay were created, and well, for a lack of parts.



The Blue Bear’s frame is flexible and I would say of fair stability, even with the z24’s and axles. The way the legs and feet work together provides for good stability. Though I won’t kid, it does take some concentration to pose and balance. When the Mech crouches down, it is the most stable and can be pushed with some force before shifting its weight. I like how it looks, like it is about to jump:


more pics...

The frame is 21 inches tall, it can reach up high too:


640x480

Standard size
   
1600x1200

Large size

I will replace the shoulder splay clips with the ones that have the rubber insert to make that joint stronger.




Here is the final Mech completed.

For me this is not as much about a “Frame” as it is in the components and variety of joint types for specific uses. Then putting select components together to form the basis of the mecha joints. The neat thing is when all the components come together.

I didn’t set out to make a universal builder frame, this is just a series of pictures I took before the joints became covered or blocked from view.

Though I would guess a pure TECHNIC scale armature would look very similar, along with the many great frames built by other builders. Many of those frames use TECHNIC. Anyway, I just didn’t want any readers to think I was presenting a frame of my own. Each skeleton I build for my mechs are specific to the creation, though some joint tech is interchangeable. Just want to clarify.

Enjoy! ...and I hope that help to see how the joints work.





Blue Bear - Joint Tech Frame Page
Blue Bear - Full Gallery

   Well done
Marco

Thank you.

-eric



Message is in Reply To:
  Re: Blue Bear
 
(...) ==== Hi Eric, this is amazing. I like how you combined gears and ball joints on Blue Bear. (URL) This is my favourite pose. Seems to me as if he's a surfer. Overall Blue Bear doesn't look as sopieesque to me as your former mecha. Your style is (...) (18 years ago, 31-Oct-06, to lugnet.build.mecha, FTX)

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