This is what I found on the web site. 

**Belt Driven Model**

![Belt Driven Model][1]

**Screw Driven Model**

![enter image description here][2]


I suggest that reviewing [this][3] document


  [1]: https://i.sstatic.net/KWSao.png
  [2]: https://i.sstatic.net/99O5N.png
  [3]: http://www.kollmorgen.com/en-us/products/linear-actuators/rodless-actuators/r4-series/_literature/r3-r4_drive-shaft-installation_en-us_reva/