Since mid-2020, EDELRID has been advised of 32 cases (as of June 18, 2021) showing defects with the 28 mm Triple Lock (TL) buckles on the TREEREX harness. In the majority of these cases, the plastic housing on the buckle had loosened, and in some cases, the housing had completely detached itself from the mounting.
Since the first case, EDELRID has been heavily involved in investigating any potential risk and the cause of the problem, finding that the "three-way operation" of the buckle opening mechanism makes it impossible to open a TL buckle with a harness put on and pulled tight.
After a risk to users was ruled out, the case was assessed as a production irregularity, affected buckles were replaced, and the buckle design was modified to rule out any similar occurrences in the future, regardless of the specific cause. This updated version will be used in the manufacture of subsequent TREEREX harnesses from 2021 onwards.
On June 9, 2021, a 45 mm TL buckle was discovered for the first time in the USA on a NOTCH branded arborist harness where the buckle housing had detached itself from the supporting mounting.
While investigating this case, as part of a collaboration with NOTCH and the suppliers of the buckle components, EDELRID has now been able to pinpoint the probable cause of the defect:
In all buckles scrutinized to date, changes in the riveting process were found, but they were always within the intended tolerance range. Furthermore, the buckles examined did not show any deviations in incoming goods inspections and standard tests. During the investigation of the current case, it was found that the stiffness of the plastic housing exhibited minimal variations. These fluctuations are negligible due to the nature of the processes. However, if a rivet that is at the lower limit of the permissible tolerance range is used in a housing whose stiffness is also at the limit of the tolerance range, the attachment of the housing to the mounting is no longer fully ensured.
EDELRID has been using the TL buckles in its harness designs since 2016. The riveting process has been modified as of buckle batch ZU0119. As things stand today, buckles from previous batches are not affected by the current problem. No comparable cases have been reported for other harnesses with integrated TL buckles, which have been used in many applications since 2019. We suspect that application-specific peculiarities of tree care additionally exacerbate the occurrence of the defect.
A detailed description of the design and use of the TL buckle can be found here: