Tech & Installation
Turn key and the lock cylinder will pop out allowing the black pin to drop down. Then slide the orange lock frame over your stamped steel coupler flange.
Lift the black pin up until it fits flush with the bottom of the orange lock frame.
With key in the straight up and down, push the key and lock cylinder into the lock and rotate 90 degrees to lock the black pin in place. Your trailer is now secure!
The latch handle of the coupler must be in the locked position. Some latch handles need to be pushed back slightly to accommodate the lock sliding into the correct position.
Not all couplers are the same
Madlock Trailer Locks are designed for “stamped steel” couplers which are the most common type and should be easily recognizable by the prominent flat lip flange at the base of the coupler.
Locks are sized specifically for a 2 5/16” ball or 2” ball couplers. The maximum flange width for each can be measured at the base of your coupler as pictured.
Sizes as listed below.
2 5/16" Ball = Max flange width of 4 3/8”
2” Ball = Max flange width of 3 5/8”
What is a stamped steel coupler?
Stamped steel coupler
Stamped steel couplers are formed from a single piece of steel which creates a flat lip flange around the base of the coupler.
Madlock utilizes this flanged lip for it’s secure fit & function. Stamped steel couplers are the most common type on the market.
If you are in doubt, please enquire.
Cast coupler
Some couplers more common in industrial applications are manufactured with “cast steel” and do not feature a prominent flat lip flange at the base.
If you have a cast coupler Madlock will not currently fit your trailer. Our next design is in progress.