Spillard News

Spillard have launched their third generation Roll Over Restraint seat and harness – on the face of it not earth shattering news, but when you realise that this is probably the first Roll Over Restraint that most operators would willingly wear, its Big News

The value of wearing a full harness in terms of safety has been well understood for many years, the problem however has always been the discomfort experienced by a plant operator whilst wearing one. It is all well and good pointing to an F1 driver belted up for a grand prix, but he does not need to wear it for eight hours a day whilst experiencing a ride similar to a bucking bronco.

Spillard’s motivation for such an improbable idea was a report published by the HSE called ‘Seatbelt performance in quarry vehicle incidents’. This became the catalyst for Spillard to develop a third generation Roll Over Restraint as the report challenges the industry to reduce effect on operators of roll over situations. As providing safety solutions is part of the Spillard ethos, the challenge was accepted.

Part of this very comprehensive report is a comparison of the relative effectiveness of restraint systems in constraining the operator within the cab survival space during a roll over. The harness (a Spillard/Sears 4065R 2nd generation seat) was found to be the most effective method or retaining the operator when tested against a lap or lap and diagonal system.

The harness restrained the manikin within the cab survival space. The lap belt did not restrain the manikin allowing it to make contact with the interior of the cab, whilst the lap and diagonal belt (designed for frontal collisions in automobiles) was ineffective when the roll over occurred in the opposite direction to the restrained shoulder.

The challenge now was how to make the most effective belt systems comfort level acceptable to operators when worn on a day in day out basis. After much consideration Spillard settled on a full harness secured at three points through three retractors and integrated into a Sears high back operator seat.

One of the design criterions was to offer a solution to a perceived problem, which occurred in a slow roll over situation when low momentum forces fail to activate the inertia reel allowing the belt to play out without constraining the operator. A solution was found by using reels, which reacted both to inertia and a tipping moment from the vertical plane.

Consideration was also given to preventing dirt ingress of the belt webbing by constraining it within the seat, the danger of dirt ingress had been also highlighted in the report.

A prototype was fitted into a customers articulated truck and Barry Robinson MBE was challenged to put it through its paces (Barry, to be fair was not a fan of the comfort afforded by the traditional harness). The design team were delighted with Barry’s report which indicated that with a couple of small changes it was fit for use commenting: “I noted at times that I could not feel any discomfort at all, you could not tell if the harness was being used.”

The next step was to test the complete ROR seat and harness at MIRA to SAE J2292 the standard for harness arrangements. To pass SAE J2292 the ROR needed to withstand a simultaneous pull of 9,000 Newtons on the lap webbing and 7,000 Newtons on the shoulder webbing for a period of ten seconds (this is the equivalent of hanging a family size car from the belt system) It’s a harrowing feeling seeing your hard work being subjected to destructive testing, but its great when it passes and at least you have a certificate and a video to prove it.

So with the SAE J2292 testing completed even more stringent testing began. A number of preproduction ROR seats were fitted into customer’s machines, in real work situations and most importantly with real operators.

The results were very encouraging, with operator comfort ratings of the new harness arrangement equal or better than that of the operators usual lap belt comfort. One predicted downside of the harness materialised when it was tested in applications, which required the operator to get in and out of the cab on a regular basis. The level of inconvenience of buckling up was however found to be less significant than previous harnesses as the three retractor system required much less adjustment.

As a result of the very positive operator acceptance during the preproduction trials Spillard are to start production, with the ROR Seat and Harness being available for sale towards the end of the summer.