DOUBLE 360°
CABLE CARRIER
2015
A further development of the IGUS rotary motion carrier system for doubling the cable amount in a 360° swivel system
IGUS is the world leading supplier of cable protection solutions, usually in the form of plastic link chains that limit the movement and bending of cables in a moving mechanism.
When looking at the best implementation of cable management in a operator chair swivel base, there are requirements to be considered:
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A large amount of cables are needed to pass through the rotation
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The swivel joint needs to travel ±180°
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Static floor surface at the center of the swivel, as large as possible since chairs are often rotated manually at speed due to emergency exit situations
The existing IGUS rotary motion system requires shaped sheetmetal guides that attach to the static and rotating parts to control the movement of the chain.
The chain also has a different bending radius limiter on the inner surface (large bend) and on the outer surface (small bend) in order to keep the shape.
In order for this to work at angles greater than ±90°, the inner (static) chain segment must be supported by curved sheetmetal (blue) coupled with the rotation. The outer (rotating) chain segment must be supported by curved sheetmetal remaining static (grey).
The two inner curved sheetmetal guides are not required for rotation angles under 180°, as shown below:
IGUS rotary motion system, with single cable chain and curved sheetmetal guides, allowing 360° rotation with 1 chain only.
Credit: www.IGUS-CAD.com
US Navy LaWS laser system with swivel base cable solution for rotations under 180°.
Note the piggyback solution of 2 cablechains in parallel.
Credit: U.S. Navy
Doubling the capacity with an innovative solution
When minimizing the size of the system, pairing two symmetric cable chains as shown above doubles the amount of cables with a given bending radius, but will not work with the curved guides that are mounted to the static floor and the rotating element, as they will only work with a chain on one side. "Piggybacking" double chains only works when the outer dimensions of the whole structure can be increased.
For operator chairs with static centers for supporting a standing user, I needed to keep the center volume as big as possible for structural strength.
In order to acheive this I adapted the solution to consist of 2 symmetrical chain loops, and a floating horseshoe shaped plastic guide that slides on the inside of the chain loops at ½ rotation speed.
WITHOUT FLOATING GUIDE
Installing a set of 2 symmetric chains from the old standard solution and rotating above ±90° will create the problems shown in this video.
A different approach to guiding the pair of symmetric cable chains was needed.
Test showing problems when double rotary chains move without floating guide
FLOATING GUIDE
Double chain solution for ±180° rotary motion with plastic floating guide