Here is the first attempt to build a complete mechanical loom, which works but is not enough reliable.

I will present you my work around loom machine.  Of course it is not the first attempt, I have made lot of attempt, searches and I present you the first working prototype. To read the complete development, you can read the translated page of setechnic. The aim is to build for the exhibition Fanabriques 2012 a automated mechanical loom (no RCX-NXT) which is capable of weaving  non stop during the exhibition (except maintenance time).
The prototype is quite validated. Concerning the functioning, I encourage you to read the article on Wikipedia : http://en.wikipedia.org/wiki/Loom it explains very well the functioning.Which is composed of:
1. Wood frame
2. Seat for weaver
3. Warp beam- let off
4. Warp threads
5. Back beam or platen
6. Rods – used to make a shed
7. Heddle frame – heald frame – harness
8. Heddle- heald – the eye
9. Shuttle with weft yarn
10. Shed
11. Completed fabric
12. Breast beam
13. Batten with reed comb
14. Batten adjustment
15. Lathe
16. Treadles
17. Cloth roll- takeup
My model is a flying shuttle model. Here is the basic cycle of weaving:

• The heddle frames move up

• The shuttle moves from righ to left

• The reed moves  and press the weaving pattern

• The heddle frame moves down

• The shuttle moves from left  to righ

• The reed moves  and press the weaving pattern

And the cycle is repeated. Now how I built that ? I have first of all build a basic chassis which support all the component:Then I have put in place a basic system of slider to lead the shuttle :You can see here the group of  reel which composed the 22 thread of the shed.After that, I have made the system for moving the shuttle called the pitcher (the green liftarms) :Each pitcher is linked with a rubber band in order to launch the shuttle. To make the movement and tighten the pitcher and the rubber band, I use a cam with variable profile. It is composed of 3 corner 3×3 technic. The last empty corner is to generate the launch of the shuttle :And in order to have a accurate pitchers, I have made two device of pre-tension. Indeed, the accuracy and velocity of the shuttle linked to the pitcher depend lot of the stretching of the rubber band.

At the end, all setting will be displayed on multiple dials (speed, pre-tension, movements). Also, after the group of reels, I have made two drums which grip the  22 thread of the shed in order to unroll slowly the shed and to control the tension for the sheed (again important for the functioning). The crossed reed is used to avoid the snarl.On the front, it is a big drum which winds  the complete weave. All drums are going to be synchronized in order to have a slowly and constant forward movement.Concerning  the shuttle, it is very simple and yet not so simple. Indeed, the shuttle must be smooth as possible in order to slide smoothly in the shed (no stop, no clash, no bump). That is why I used liftarms which have rounded shape. On a shuttle, 10m of thread is winded.Now concerning the « mechanization » of the loom. First of all, a XL motor with  2 8t/40t gear drives the main shaft. The shaft drives after the two system of cam for the pitcher and the system of control the heddle frame. Here is a underneath view :On the right and left view, you can see in blue the mechanism of control of the heddle frame. The system is not based on well-known lever and connecting rod. I use a lever but with a sliding connecting rod, also considered at variable length connecting rod. This system enable to have a output intermittent movement which is better for the application than linear motion.To finish : the loom works, it works good but not really accurate. I need to improve the accuracy and reliability. That is why I will build a second attempt by modifying the system of launcher. Indeed, as shown in the video, sometime, the shuttle doesn’t pass through the threads because of many small things:

• slider a bit smaller

• the reed a bit wrong placed

• the thread a bit not enough tight

All these faults are due to the system of rubber band which affects the right setting  (by constraining the structure and the impacts). That is why I will create a pushed shuttle system instead of launched shuttle system. Thanks to that, even if there are some fault, the shuttle will even passed because it is pushed.
To finish, the video :