A lego braiding machine, powered by a single motor, which makes ropes and wristband.
After my mechanical loom is 2012, I wanted to build more specific weaving and braiding machine. After months of research, I came back with a new idea based on rope maker : a braiding machine which can make of course rope but also wristband ! Then, I have started in April of 2013 to make some prototype of weaving and braiding machine and succeeded in making one truly functional in December of 2013.
How does it works ?
Basically, the braiding machine is composed of :
- A frame, mainly in yellow color which handles the mechanisms and features
- A big drum in gray color with the big circle which can rotate (driven by a turntable)
- 3 planetary devices which support 3 reels each and can also rotate (driven by a linked-chain)
- 3 reels on each planetary (therefore 9 reels) which can also rotate (driven also by 3 linked- chains)
- 3 die for weaving 3 strings in one (will be called the planetary dies)
- A principal die which weave the whole 3 weaves from planetaries in only one final weave
- A mechanism for pulling the whole weave
- A final drum system with alternate moving winding system to store the fabric
Everything started on the planetary system. 3 Reels are attached in one planetary. During the rotation of the principal drum, the three planetary turn in counterclockwise, while the 3 reels on each planetary turn in clockwise. You can see on the picture the main chain-link which drives the whole planetary and on the front the chain which drives the 3 reels on a planetary.
The 3 reels of one planetary then pass through a pulley with 6 holes and then in the die which is fixed in the drum. As the die is fixed and the planetary is mobile, the three string are forced to match together in one weaved string. The fact that each reel can turn on itself in counterclockwise of the planetary ensure that the whole weaving string doesn’t taken apart when they meet together. This is the important thing to understand how the weaving is working.
After this, 3 weaved string are in the weaving machine, then, they are interweaved to create the final wristband fabric. This is the role of the principal die (with the big white wheel). It works on the same principle as the precedent die. The wheel rotates with the 3 strings in, and the die (here is a liftarm T-shape gray) is fixed on the frame, the combination of the movement forces the 3 strings to meet together. And as the same principle seen above, each 3 weaved string rotates on itself (because the string is linked to the rotation of the planetary), which ensure the final fabric to not takes apart.
At this stage, the weaving fabric is made, then there is the pulling system which ensures the roll-out of the wristband. It is composed of 4 wheels which are tighten up by a spring. The final fabric passes through the 4 wheels, and as the 4 wheels is powered, it pulls the fabric. This part was certainly the most difficult part to create because of the many problems concerning the tension of the string and the rigidity of lego system. This final solution seems to be simple but there were many other tests before finding this.
And to finish, the final fabric are stored on a drum with a automatic alternate winding system (in blue on the picture). This system is composed of a drum and a device in blue which can be moved from the left to the righ and lead the fabric to wind correctly on the drum.
The functioning of alternate winding system is very simple. The blue device is linked to the drum with a linear motion gearing. When the device has reached the top point of left or right, there is a switch composed of a lever with a connecting rod which switches the rotation of the device, and then it goes on the other side. The inversion of the rotation if composed of a translation axle which drives a bevel gear with a gear or an other, the layout of the two bevel gears makes that the rotation inversion possible. The functioning is shown on the video and certainly more understandable.
To talk about performance :
- The braiding machine is set up in 15 minutes (place the 9 reels and pass the whole braids in the device),
- It weaves at 35cm/minute until the reel is fully empty
- Each time you setp up the loom (set up the 9 reels), 30cm is wasted (corresponded of the whole distance between the reel and the winding system)
- Each reel can be full of 3 meter of string which make around 1m50 of final wristband
- The braiding machine is really reliable, it can run with a motor by itself and make all braiding and stop until it has done (the winding system continue to turn but it has no consequence for the device).
Video and pictures
The video shows the functioning of the weaving machine and also the quality of the final fabric :
Blakbird has made some rendering of the mechanics :
You can se easily the whole compenent of the mechanical systems.
To conclude, this braiding machine were a big project for a long time ago for me. I have made many try and re-try and finally succeeded in making on different loom for the previous which can also weave fabric. The construction is also rather simple and very demonstrative for people who like mechanics, or kinetic art. I have made the design and color-scheme big points of the development of this project.
Now, all you want is to know if there are building instructions ? And there are ! Not really a professional building instructions but a photo-sequence which shows all the parts and the sub-assemblies. The bill of material is available at the end of the instructions in picture file, or can be downloaded in brickstore file here (many thank blakbird for making the bill).
The two Zip-files for build and set up the braiding machine :
You can also watch them online :
The building instructions :
How to set up the braiding machine :