Action item list with the status of items involved in the updating of the UN Regulation on mechanical couplings.

E-mail exchange between the R55 informal group chair and the Lohr group concerning drawbar and fifth wheel designs.

Proposal to modify performance calculations and limits under UN R55. Currently UN R55 prohibits a vehicle combination with required performance values Dreq, Dc-req, Vreq and Sreq where Dc-cert ≤ Dc-req ≤ Dcert and Vreq ≤ Vcert. However, a requirement combination such as Vreq = 0.1* Vcert and Dc-req ≤ Dcert +0.1*( Dcert – Dc-cert) better reflects the real-world situation commonly found in combinations comprising a rigid truck, converter dolly, and semi-trailer.

Estimation of test force F times distance, L, from drawbar eye to turning center, i.e. F*L on one axle, two axles, and three axles.

Review of in-use requirements related to towable mass and coupling equipment towards development of an appropriate evaluation procedure for use at the time of type approval.

Proposal to require information on the maximum weight for a towing vehicle for declaration on the type-approval plate. This proposal responds to the discussion on a 32-ton weight limit which is an EU regional limit not acceptable across all stakeholders. Sweden proposes to satisfy the European interest through this informational requirement without instituting a blanket weight restriction.

Remote indicators confirm the status of a truck-trailer coupling. The intention of this proposal is to open the definition of ‘remote indicators’ to some systems currently on the market where the remote indication is not in the vehicle cab but on the side of the vehicle (on the chassis) close to the remote control.

Comments for discussion concerning the draft Supplement 4 to the 01 series of amendments to Regulation No. 55 as submitted for the February GRRF session (document GRRF/2014/14), proposing clarifications, in particular to align the text with ISO 7641:2012.

Response to the proposal (in document R55-05-12) to require more information from manufacturers on towbar fixing points in order to facilitate the work of technical services and approval authorities.

Recommendations on test conditions for drawbars and couplings, including hook and pin couplings.

Diagram to clarify the clearance of the drawbar coupling in Annex 7 of the regulation (Action Item 12 of the informal group).

E-mail correspondence with regard to the application of provisions in New Zealand standard NZS5446:2007 for tyre scuffing forces to the approval of drawbars for lateral forces under UN R55.

Requirement of a brake away cable also for drawbar-couplings

The expert group on UN R55 submitted document GRRF/2014/14 to update the requirements for mechanical couplings, including a proposal to replace the references to IS0 7641:1983 with ISO 7641:2012. In response to issues raised within GRRF, the experts prepared a new proposal (document GRRF/2014/28). This document would supplement the proposal by providing additional information on the differences between the 1983 and 2012 versions of ISO 7641.

Observations on type-approval and “in-use” requirements under UN R55 and proposal to develop a new Annex that would provide a more coherent approach to evaluating/limiting acceptable in-use stress loads than in the current regulation.

Status of the various items under discussion for the updating of UN R55 on mechanical couplings.