iLSM Tray Holder Clips and Replacement Latches - Safety Impr

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Letter to Branches




No. 992 /11
Ref C12
Date: 24 November 2011


To: All Branches with Royal Mail Members

Dear Colleagues

Re: iLSM Tray Holder Clips and Replacement Latches - Safety Improvement Programme:
 
Introduction:
This is a report to Branches on a solution to the ongoing issue with iLSM tray holder clips failing and which the Health, Safety & Environment Department have been dealing with in conjunction with Royal Mail Engineering (RME). This is to bring you up to date with where we are and what RME are doing.
 
Background
There has been a long-standing issue the Mail Centres with iLSMs regarding the failure of tray holder retaining clips on sorter modules of iLSMs– notably those on the upper tier. These control the movement of tray holders that sit under each selection on the sorter module and if a particular clip fails on the upper sorting tier, trays can slide out, uncontrolled and strike operators who happen to be in the way. This has resulted in both injury to operators when tray holders slide out unexpectedly. They can also drop/tilt prematurely onto the lower sorting tier mechanisms causing machine damage to the parts underneath. We’ve had numerous incidents involving both of these examples. Several versions of replacement clips were tested and trialled until finally coming to the conclusion that it was not possible to guarantee that the intrinsic clip design can prevent either of these problems.

Working with the manufactures 'Solystic' 4 alternative solutions were presented for consideration and after some debate, it was jointly decided that the best solution is a latch mechanism attached to the underside of the upper tier tray holders that holds the holder in place and can only be released by activating a thumb catch as the tray holder is pulled out. This design has itself underwent a number of revisions and the final version was thoroughly tested by 'Solystic' in France before being passed to Royal Mail. This 'Solystic' tests were to prove the design longevity with the aim being a mechanism that had at least a 5 years’ lifecycle – up to 50,000 activations.

Solystic have provided a number of productionised latches and the plan is to fit these to iLSMs as soon as possible to remove the risk of further injury and damage. Royal Mail are now replacing a single clip that governs the movement of the upper tray holder with a latch mechanism that cannot slide until a catch is disengaged by an operator. This represents a change to operability on the upper level but eliminates the risk of injury when tray holders slide out and it also dramatically reduces the risk of machine damage if they tilt prematurely.

Roll Out Programme
The first prototype was fitted to one of the iLSMs in Swindon Mail Centre with pictures taken in situ and in operation. The programme of fitting the latches started in the South Midlands Mail Centre and the modifications should be completed in Jubilee and Norwich Mail Centres. The programme is underway. RME have agreed access with the Mail Centres. It takes up to 3.5 days to fit latches to the upper sorting tiers of 224 box machines and the opportunity will be taken to replace those module covers that were modified because of weak or missing gas strut welds. There will be a break from any modifications from the end of November to early in the New Year and this will give 'Solystic' time to produce latches in sufficient numbers to fit to all remaining iLSMs. iLSMs not yet installed will not have these factory fitted but again as part of a retrofit – ideally before the machine is handed over. The latch rollout will recommence in early January – the sequence is yet to be determined but will include all iLSMs. The intention is to complete the retrofit modified clips as soon as possible.
 
Latch design
The latch mechanism does not replace all clips – in fact it replaces just the single clip on the upper level that holds the tray holder in place. All other clips remain and will continue to fail at the same rate as at present. RME will continue to work with 'Solsytic' to improve this situation but RME in conjunction with 'Solystic' felt that enough had been done now to control the ongoing safety risk. It requires that a lever be moved by the operator’s thumb to release the latch and allow the tray holder to slide out of position. It’s been designed to fail in a “safe” condition i.e. if the thumb lever fails for some reason, the tray holder will remain in position. In this way injury to operators when a tray holder slides out to strike the body is eliminated. In all of the tests, friction has caused the first section of the two-stage slide system to move fully out before the second stage slide and tilt comes into play. This means that even if both of the pair of clips controlling this second stage fail, the tray holder will not tilt until in the proper position – practically eliminating the second risk of machine damage as the holder drops too far and strikes the lower tier paddle rod. RME say 'practically' because although they haven’t been able to replicate this in the tests, it is not actually designed out.
RME believe however the likelihood is reduced to an acceptable level. The latch is made from plate steel attached to the underside of the tray holder. This reduces slightly the gap between the tray holder and machine parts underneath. It is still possible to remove twist belt covers with the reduced gap.
 
Communications
RME have created a series of documents to communicate the change including a One Page Lesson (OPL), Talkabout briefs, training material updates for both machine Operators in the operation of the latch and at the same time a more detailed explanation has been produced to provide engineers with details of the change to the machine. SOP and SOM audit revisions have been made. The details and information about the latch have also been included in the most recent Programme newsletter 'Get With The Programme' and also in the weekly maintenance newsletter editions. The documents have been distributed to operational and technical trainers so that training material can be updated.
 
Conclusion
We are satisfied that this rework modification remove a low level but long outstanding safety risk to machine operators. I would like to thank Kenny Wright CWU Engineering Safety Rep from my Engineering Safety team for the work done on this subject along with Richard Moor Royal Mail Sortation Automation Programme Manager and Richard Stratford Royal Mail Engineering for their detailed attention to this matter.

Yours Sincerely


Dave Joyce
National Health, Safety & Environment Officer