How does a Trailer Hitch Coupler Work

First off, what is a trailer coupler?

A trailer coupler is a device that connects the hitch of the tow vehicle to a trailer. They come in many different sizes and types, but the trailer coupler must match the tongue on your particular trailer. They all work by clamping around the trailer hitch ball. You must first determine your vehicle's towing capacity and maximum tongue weight.
Related: Types of Trailer Hitches

How does a trailer coupler work?

When you flip the lever of your trailer coupler to its locking position, the clamp is pulled up to the underside of the hitch ball. Proper installation of your coupler is crucial for safety as well as maintenance. If you've ever experienced a trailer mover not working properly for you, a majority of the time it is because the coupler isn't installed correctly and the hitch ball could be loose underneath. You also risk damaging your trailer unit if the trailer coupler is not installed properly.
Related: Trailer Hitching Guide for New RV Owners
https://www.youtube.com/watch?v=9oJKr9r6U3k
 

Installing the Standard Straight Tongue Coupler Properly

https://www.youtube.com/watch?v=pSD8pfcYZKs
 

Installing the Square Boat Coupler Properly

https://www.youtube.com/watch?v=owhHPIHJOZs&t=75s
 

Installing the Sleeve Lock Bulldog Coupler Properly

https://www.youtube.com/watch?v=W-Ct4smG4HU&t=1s
 

Installing the Cast Steel Coupler Properly

https://www.youtube.com/watch?v=Ox3M8VF3qXE