Guide:Advanced brown techniques/Arms

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[edit] Arms

This article is part of the Advanced Brown Guide. Arms are used for reaching far away, whether it be extending the arm to put a goal piece into the goal, or something simple like pushing an object on a far away horizon. The difference between arms and bridges is that bridges usually let the goal piece travel across it, while arms extend outward with the goal piece attached to the end of it. In the Rectangle Retrievers section, there are a few types of bridges; most of the time you can make a bridge into an arm and vice versa. But getting to the point, the types of arms shown below aren't in the bridges section because they are more suited to reaching.

[edit] Slide-out arms/Underpults

Credit goes to RockstarM for the concept. This is a useful mechanism if you have a tight opening build space, and it is an alternative to Jon's underpult design.

Add a weight and timer of your choosing, using a large amount of weight to overcome the frictional force that you will encounter later on.
Build sturdy platforms. The amount, size, and shape of your platforms vary according to the type of arm you make. See [1], where there are 3 platforms: one for the arm, one for the basket, and one for the goal piece.
Build a simple, long triangle on your highest platform. [2]
Add a basket-arm to the end of the first arm (the one from step 3). You can make it into a catapult from here, if you can figure it out. [3]
Add a chain between the end of the top vertex on the step-3 arm and the weight. Then add another chain from the bottom vertex to any one of the platforms. [4]
Hint: Make sure the first chain has some slack, so the weight can come out of the build area and fall for a short while before it hits its maximum tension point.
If your contraption fails, add a "guide" for the chain, so it comes out of the build area easier. This will most likely dramatically speed up your contraption. [5]
Hint: A plain supported square works best, like in the example.

[edit] Troubleshooting

The end of my chain phases through the ground after the arm pulls out of the build area.
- Double it over or make the individual chain lengths longer.

If you encounter any problems, add your problem and the most sensible solution in this section.

[edit] Examples

By RockstarM

[6]

By ~Jon~

Practice level (by Jazzmanian)

Please add any examples or levels into this section.

[edit] Zhyrek Flexer

Authored by Zhyrek. This is a more complicated alternative to RockstarM's guide, although this has the most potential for length. It's a little more suited to "vertical" build areas.

Build the frame, brace it around static objects if possible. [10]
Build a hook-structure, this is the first part of the extender. The piece placement is like this. [11] After that, enlarge the piece to fill most of the available space.[12]
Attach the "hook" to the frame with a chain. Then add a pivot triangle to the long end of the hook. [13] The chain should be almost long enough to touch the ground, and the second piece allows the extender to exit the build area smoothly.
attach another hook structure, this time to the pivot triangle. This is the pivot triangle+hook alone. [14], These are the pieces on the whole thing: [15]
Now for the fun part: Add between 25 to 35 sticks to the joint that is being pointed at, more if the distance is further, do NOT construct the arrow. [16] Notice how the centripetal force snaps the hook into a flat arm.
Almost there! Now add the final part: [17] (Just the arm) [18] (Complete design)

[edit] Troubleshooting

A joint doesn't bend/bends too far.
- if it doesn't bend, make the triangles on the joint thinner, if it bends too far, make the triangles on that joint wider.

A triangle/arm joint shreds apart.
- Joint order is the problem here, you should re-connect some of the joints until they stop breaking, OR you can reduce weight.

My contraption doesn't reach far enough.
- Length can normally be added to almost every part, but I believe the physical limit for distance is the perimeter of the build area.