Keeper Plate

Definition

A keeper plate, also called a restraint hook or barrier hook, is the moving arm on a dock-mounted vehicle restraint that pivots up to engage a trailer’s rear impact guard (RIG), physically preventing the trailer from separating from the dock while it’s being loaded or unloaded.

What Does Keeper Plate Mean?

The keeper plate is the actual point of contact in a RIG-style vehicle restraint. Once a trailer backs into position, the restraint arm rises to hook the rear impact guard, and a sensor or interlock confirms engagement before dock crews are cleared to open the leveler and start work.

Not every trailer has a RIG in good enough condition, or positioned consistently enough, for a keeper plate to engage reliably. Older, damaged, or non-standard bumpers are common culprits — which is typically where wheel-based restraints like wheel chocks come in as an alternative.

Key Characteristics

• Engages the RIG — hooks the trailer’s rear impact guard rather than the wheel
• Interlocked — most systems tie engagement to the leveler and door controls
• Adjustable on some systems — interchangeable hooks accommodate a wider range of RIG heights and styles
• RIG-dependent — needs a compatible, undamaged rear impact guard to engage reliably

Why Keeper Plate Matters at the Dock

The keeper plate is the component that actually decides how reliably a facility can restrain the range of trailers that show up at its docks. DockStar’s Dual Barrier Vehicle Restraint uses adjustable, interchangeable barrier hooks — functioning as the keeper plate — designed to accommodate a wider range of RIG heights and styles than a fixed hook, plus a dual-track design that spreads restraining force across the system.

Related Terms

Chock

Kick Plate

Rear Impact Guard (RIG)

FAQs