What is their official name?
Andrew Larder
Author knows that there is nothing more important to feeling good at work than a great desk and executive chair.
Author knows that there is nothing more important to feeling good at work than a great desk and executive chair.





It is called a compressor.
“The compressor must keep functioning to hold the papers tightly. “
http://www.answers.com/topic/file-cabinet-1
Edit: Props to DIY Doc for his ingenuity. A heavy duty bookend in the back of the cabinet might serve your purpose, as well.
Give the 10 to Noni, and certainly they don’t exist in all file cabinets, especially in the low end prices. The drawers require extra TOOLING, that adds to a price point, at sale.
Your other Q asks how to, and that may be more of a challenge. Certainly you might pirate one from another unusable file cabinet, but you’d still have to craft the holes for the locking/adjustment mechanism. Being creative/inventive you might devise or find a mechanism that works using pressure, in expanding and against a plate at the back of the files, to the back of the drawer. It might be similar to a pressure Shower curtain rod, or pressure curtain rod for a window.