Turret Joint by RobertLRead

Last crawled date: 3 years ago

Note: After building this, I learned that it was essentially invented in 1999 as expressed in this patent by Se-Kyong Song, Dong-Soo Kwon, Wan Soo Kim. This joint should really be called the "Song Kwon Kim" or SKK joint in honor of them. However, "turret-joint" better captures what it actually is shaped like. Their patent has since lapsed, so you need not worry about patent infringement.
This is a new kind of joint which allows multiple members to come together at a single point with some flexibility in their angles. This allows us to make a strong joint for implementing irregular space frames or robots constructed from linear actuators.

NOTE: My initial testing with moving actuators suggests that although the joint works, it is quite "frictiony" when printed on the Fast setting on a Replicator 2---which makes sense because it is visibly striped and rough. However, to be an EFFECTIVE mechanical joint, we may have to increase the resolution of the print, or even provide lubrication. I'm trying to test thoroughly before I take that step however. The current joint should be considered a initial design and a work in progress, not a finished product.
You may want to watch my YouTube video explaining this.

... or my video showing the large robot in action:

This is a collection of things which work together to form a construction system for building spaceframes, or moving robots, that allow some angular displacement in the members, without sacrificing strength or structural integrity.
The fundamental innovation here is that the rotors can move, up to about 30 degrees, without loosing any structural strength, because they are always pointed precisely at the center of the joint. Up to manufacturing tolerances, the joint does not introduce an "slop" or new degrees of freedom in the central point when bringing members together. This allows us to make trusses and spaceframes that are curved or wavy or in other ways deviate from purely equilateral triangles, without having to create a new joint for each angular displacement.
This system has a number of pieces. The fundamental parts are the ball, the lock, and rotors. The lock holds the rotor against the ball and ensures it always is pointed at the center of the joint (which is the center of the ball.)
Separate parts include separate caps that can be screwed to the locks to produce joints of different numbers of elements coming together. As presented here, the geometry is based on the Cuboctahedron, leading to the construction of Octet Trusses as patented by Buckminster Fuller in 1961. However, one could easily design different configurations.
It includes rotors specifically to mount the Firgelli L16 linear actuators and carbon tubes. These should be considered design starting points for mounting other members.
The system is scalable. It can be scaled down to the point that your members start to collide with each other.
This is an open-source hardware project meant to be a gift to the whole world. Do not attempt to patent it, which would be illegal and fraudulent. However, please manufacture it and make money with it in any way that you can.
I look forward to your comments and contributions. You may wish to join our team (you can be the second!) or promote our project, Public Invention (For All Humanity), PIFAH where many other nascent are ideas are published, and you may wish to subscribe to my YouTube channel.
To contact me directly, send email to read.robert@gmail.com