The End Fixity Primer

Christopher Nook by Christopher Nook

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What is end fixity? End fixity refers to the method by which the ends of the screw are supported. The degree of end fixity is related to the amount of restraint of the ends of the screw. There are several types of end fixity, including: simple end fixity, fixed/free fixity, fixed/simple fixity, and fixed/fixed. Today, we'll go through all of these examples. 

Simple End

Fixity of this kind can be provided through a single bearing support:

Free-simple-fixed-1.png

 

Multiple or spaced pairs of bearings are more rigid than a “simple” support, but because of their compliance are not truly “Fixed”.  A screw can be support with different combinations of end fixity.

Fig8TypA-1.png

In figure A, one end has a Double Bearing EZZE-MOUNT™ and the other end is Free. This would be recommended for short travels and slow speeds. 

Figure-8-Type-B-1.png

In figure B, one end is supported with a Double Bearing EZZE-MOUNT™, the other end is supported with a Single Bearing EZZE-MOUNT™. 

Fig-8C-1.png

 

Both ends in figure C are supported with a Double Bearing EZZE-MOUNT™.

EZRFFig-D-2-1.png

Both ends supported with a Quad Bearing EZRF EZZE-MOUNT™.

NOTE: When supporting a supporting screw with two Quad Bearing EZRF Mounts, the screw is highly ridged and extra care should be taken to insure compliance in the assembly design.

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