This is my first attempt at trying to build a spring loaded prop. as it stands only the middle sections are retractable. you will need to insert a couple of small springs on the half moon pieces to make the buttons function and then make a custom spring to sit inside the detailed grip bar, which when the buttons pressed will force the section to its fullest. i have not printed this yet to test and will continue to develop the outer pieces to also be spring loaded when i have the time. alternatively you can have the piece constantly at full length.

you will need to duplicate the obj to make the other side