The workgroup chairman Jürgen Westphäling welcomed all experts to the meeting venue at Tüv-Süd in Garching.

R55-02-04 | Draft agenda (online version only) Agenda posted in .msg (Outlook) format: https://www2.unece.org/wiki/download/attachments/4064546/R55-02-04_Meeting%20in%20GRR%20R55%20informal%20working%20group%20October%202012.msg?api=v2

There were fourteen experts that attended the meeting. Apologizes were received from Mr Ittersum of Thule NL and Mr Bailey of DfT UK. A call around the table was made.

Mr Hansen gave a short report from the GRRF session in September of 2012. An informal document with the proposal for Terms of Reference (ToR) had been submitted from Germany to the GRRF. However at the actual meeting the time schedule was so tight, that it was decided to postpone this subject to the February 2013 session. Faced with this situation the working group still decided that this second meeting will proceed as planned and according to the proposed ToR.

Further information from the GRRF was that there was a new chairman and a new secretary. The secretary was Mr. Fransois Guichard who had left Daimler AG to take on this assignment.

Of relevance to this working group it was also noted that the ToR for the informal working group ACV was extended to address road trains in connection to the regulation 13. The ACV group has just prepared a draft proposal to amend ECE R55. This proposal should be taken into account regarding item5 (innovating products to class S) and item 11 (remote indication) and item 18 (remote controls).

The ToR for this working group included a list of items to address. This list was reviewed. Two items were added. Item no 29 on the definition of when a rigid drawbar is to be considered as an integrated part of the trailer chassis. Item no 30 on a definition what is a simple design. Both those items have been addressed for light trailers in the standard ISO7641. Furthermore it was noted that TÜV had some internal information on this and that the German Technische Anweisung 31. Mr. Svensson of VBG S was assigned to have the lead for those two items. They were classified as complex. Mr. Conrad of TÜV-Nord offered his support. He could also send a copy of TA 31 to the secretary. Concerning the calculation of the drawbars of simple design Mr Conrad offered to send to the secretary an internal document giving the procedure applied at TÜV-Nord.

A procedure exercised by AL-KO where they test the complete chassis including the drawbar was referenced. This may be possible for light trailers but for heavy trailers the problem is more tricky.

Mr Stokreef noted that the judgment of simple design or not varied between technical services.
No other adjustments were proposed to the ToR.

It was discussed whether more relevant experts should be invited. Lucien Vogel of Lohr, F, was proposed. In particular it was thought that trailer manufacturers ought to be represented in the workgroup. Mr. Westphäling shall invite someone from the German trailer manufacturers. Further CLCCR shall be contacted. The French experts had some person at the UTAC that they believed should be on the working group.

The status of the work with agricultural rules was discussed. The German rules that should be the base for the work on agricultural rules have been translated. All experts are invited to find some more experts to contribute to the work with agricultural couplings. For the time being it was agreed that the work on agricultural couplings shall proceed in a subgroup.

Initially it was decided to first process the items classified as simple.

Item 6 Simple
The issue of securing foldable couplings in the service position was discussed. First of all the proposal is that this position shall be locked with positive locking. Then the question of indication of this positive locking was the subject of a long discussion. No final agreement was reached at this meeting. It was decided to wait further input from manufacturers on test requirements adaptable on the foldable system.

Item 7 Simple
This item was discussed and in principle agreed. However the formulation shall be reconsidered by Mr. Stokreef and Mr. Westphäling. In addition there has to be an addition to the Annex 6 of a §3.2.4. stating the test requirements for the secondary coupling attachment point.

Item 8 Simple
This item was agreed without modification. I.e. the characteristic values given in the specified tables are minimum values. This means that many couplings that today are compliant with regard to geometry but have higher loading capability characteristics need not be classified in class S.

Item 10 Simple Complex
The essence of this proposal is to allow couplings with a yaw and pin configuration also to be classified in class T. However the item turns out to be more complex when going into the details. E.g. for the test forces in the endurance test a factor 0,5 applies in class T rather than 0,6 for other classes. The 0,5 factor was said to be justified by the ball type class T couplings being play free. This Item was hence reclassified as a complex item to be processed further.

Item 11 Simple
The matter of location of the indication was in principle agreed. The wording “in the cab” could be deleted. However the wording “ … in the field of vision of the driver (or operator) …” was considered to be a bit ambiguous. Some argued that when a trailer dropped or picked up at a terminal it is not OK to have only a signal from an operator to the driver. The driver shall assure himself that the coupling is OK. Mr. Teyssier, Volvo agreed to reconsider the formulation. Mr. Tagliaferri agreed to support in this task.

Item 12 Simple
Drawings showing new specification of the required free space around the coupling were shown. The experts were not completely satisfied. Mr. Zander agreed to rework. In addition he shall provide a better justification text based on a better statistics of the accidents related to these free space requirements.

Item 17 Simple
Requirements copied from 94/20/EC was agreed to be added.

Item 18 Simple
Paragraph 12.1 in annex 5 was proposed to be changed such that remote indication and remote control is allowed for automatic pin type drawbar couplings and automatic fifth wheel couplings. This is a deletion of the previous limitation to C50-X and G50-X. It was also understood and agreed that fully automatic coupling systems shall be covered by this paragraph. The proposal was agreed.

Item 23 Simple
The proposal to allow installation and/or operation instructions to be supplied only as a reference to an internet link was discussed. This subject was found to have more complexity than could be envisioned. Issues that were raised were for example change of web-addresses. How shall a general customer know where to find the instructions in such cases? The same applied if a supplier completely leaves the market. It is also a difference who actually installs the coupling. In Sweden for instance there had been a review of some 140000 class A couplings. It was found that 15% of those were installed by “do-it-yourself”. Hence the skill certainly varies a great deal. The proposal was disagreed and withdrawn.

Item 22 Complex
This Item was presented about by Mr. Svensson, S. The proposal was not formulated in a compact enough form that could go into the regulation text. However the main point of this proposal is that there are many feasible operating points of approved coupling equipment that is not accepted for operation today. The area of concern is where demanded D is lower than Dcertified and higher than Dc-certified while demanded V is lower than Vcertified. Furthermore there is also a proposal for making trade-off between the vertical dynamic load V and the static support load S. The latter is proposed to be handle through a traditional fatigue design theory like Haig/Goodman. The former issue was proposed to behandled through some simplified formulae based on a more complex reasoning that has been applied in Sweden with success. The proposal was supported. Mr. Svensson was given the task to elaborate a proposal that could be included in the regulation text.

Item 2 Complex
This concerns the unintended use of coupling equipment. The most frequent case that is seen by the general public is bicycles carried on a class A coupling. There are many other unintended applications that result in unforeseen forces on the coupling structure. The discussion was very much centered on the class A couplings. It was said that there were special procedures or directives in different countries. Germany has a national directive. AL-KO applies a maximum torque limitation. The Dutch automobile club, TÜV-Rheinland and TÜV-SÜD have their own internal procedures. RDW of NL declared that they have noticed no problems. The hypothesis was raised that those odd application with many bicycles etc. are with private car owner. The utilization of the coupling equipment of those categories is very low. Thus those class A couplings are in no way in the neighborhood of fatigue limits during their life cycle. On the other hand any final failure of the coupling need not be in the adverse use but in the normal use even though the root cause is the adverse use. This item was put on ice for the time being. It was decided that Mr. Westphäling shall investigate the accident statistics that could support the proposal. Any other expert is challenged to do the same.

Item 13 Complex
The proposal to add the Av-value to the type plate of hinged drawbars was discussed. The issue was then raised that there is a difference the Av-value for a single axle and a tandem axle front axle group. As a consequence there shall be two values (Av1 and Av2) stated on the type plate. The discussion then continued to address the background to the differences. Mr. Knut Wartenberg who was part of the team writing the original text was called in to the meeting. Unfortunately he could shed no light to the issue. He rather referred to Mr. Bonacker who is still active and who was also a member of the team. Mr. Svensson will contact Mr. Bonacker.

Item 3 Complex
This proposal concerns the static test to prove the validity of the locking mechanism of hook couplings.
The test force is tied to the D-value through a factor of 0.25. This factor is proposed to be increased to 0.6. The background to the proposed figure was not clear. Also in this case Mr. Wartenberg made reference to Mr. Bonacker. Mr. Svensson challenged why is this test force tied to the D-value rather than the V-value. Mr. Gunneriusson , S, informed that there had been some accidents (even fatal) with hook couplings on agricultural tractors due to the locking mechanism failing. In principle the proposal was agreed but the experts were challenged to get more information on the mechanisms being the basis for the factors applied. DLG will be contacted in this matter by Mr. Westphäling.

Item 4 Complex
This item resulted in a lot of discussion. The class L drawbar eye is intended for use together with a class K hook type coupling. In France this drawbar eye is used together with a pin-and-yaw type coupling with a cylindrical (prismatic) pin. This coupling is certified according to regulation 55 class S. As the class L drawbar eye is tested with a pulsating load the certifying test is not relevant for application together with a pin type coupling. It was argued whether it could be concluded that the test performed for the class L could be regarded as more severe than what is experienced in an application with the French pin type coupling. There were several different proposals how to handle this. One proposal was to design a new class. This could not be resolved at the current meeting. , Pommier is invited to outline a new class L2 intended for use with pin type couplings with cylindrical (prismatic) pin. Discussions will resume at the next meeting.

The chairman thanked all participating experts for their contribution and wished them a safe journey home. Welcome back in January of 2013. Likewise the attendees expressed their gratitude for the hospitality by TÜV-SÜD to host the meeting.

See the session report document.