Coupling Mounting

  

The coupling is a critical safety item, and one of the mounting options below must be followed completely. For mount diagrams see Hygo Techincal Data

Mount Option 1

For A-Frame Drawbars

A-frame-hygo

The Hygo MkII coupling can be used as a structural member, and bolted directly to the top of the drawbar as shown in diagram 1 (shown above).

  • Drill the hole pattern through the top and bottom of the drawbar. The front hole centres must be at least 25mm from the front edge of the drawbar.
  • Bolt through the coupling plate, and through the drawbar section.
  • A bracing member must be used between the two drawbar beams. This should be a SHS or RHS profile, and cover the drawbar depth completely. This should be welded somewhere within the coupling length.
  • Crush tubes that are a neat ID fit must be used inside the drawbar tube.
  • Grade 8.8 or higher M12 bolts must be used in all 6 x mounting holes. These should be torqued to 130Nm.
  • Plate washers >6mm must be used under the bolt heads in the four rear slotted coupling mount holes.

NOTE: A welded mounting plate can be added to this mount option if desired.

Mount Option 2

For Straight Drawbars

straightmount-hygo

The Hygo MkII coupling can be used as a structural member, and bolted directly to the top of the drawbar as shown in diagram 1 (shown above).

  • Trailparts will supply a different coupling mount system for this mounting style, where the coupling has a heavy 16mm plate with threaded holes designed to take bolts from underneath. The coupling mount hole pattern is the same as in common cast braked marketplace couplings – 54mm wide x 184mm x M12.
    NOTE: It is critical that every mounting step below is followed closely.
    NOTE: These instructions relate to 100mm deep drawbars. Fitting to other sizes is permitted, but bolt lengths
    and considerations about mounting thread engagement need to be considered.
  • Drill the hole pattern through the top and bottom of the drawbar. The front hole centres must be 25mm from the front edge of the drawbar.
  • In this mount configuration, Trailparts will supply ½” bolts and crush tubes. These must be used, as they are the same thread as the holes in the coupling, and the correct length to engage that thread as designed.
  • Assemble the bolts and crush tubes through the drawbar, then thread into the relevant coupling mount hole.
  • Tighten the M12 bolts into the coupling using a torque wrench set to 130Nm

NOTE: Trailparts stock components to facilitate this mounting as follows;

  • Crush tubes to suit M12 and ½” UNF bolts and 100mm deep box section.
  • Grade 8.8 M12 x 140mm zinc plated bolts and locknuts for mount option 1.
  • Grade 10.9 ½” UNF x 4.5” zinc plated bolts for mount option 2 applications.
  • Laser cut 6mm dual-hole washer plate for rear slotted holes.