May 16th 2017
ISC products are constantly evolving and since the first launch of Zippey more than 3 years ago, we have gathered feedback from zip operators from all around the world and fed them into an engineering review. This review has specifically been driven by a number of concerns about the variation in performance/longevity of the Zippey trolleys returned by various customers/test sites around the world. We know that different sites around the world have very different environments (humidity, coastal locations, sandy environments...etc.) and these have significant effects on the bearings.
1. Cable: Cable Construction is a key factor. Coarse cable can be of significant detriment to the longevity of the trolley and especially the bearings. There is a reasonable correlation between the coarseness of the cable ('6 x 25' cables being the worst cable type), and the life of the bearing.
We like to use the analogy of having a Ferrari and driving it on a cobbled street! You just wouldn’t! A Ferrari should be driven on smooth highways...and Zippeys (and all Zip Trolleys) like to run on smooth cables!
2. Bearings: Our investigation into the quality and type of bearings that we use found that they needed to be sourced directly from a reliable, specialist manufacturer to ensure consistent quality. After all, the bearings are the critical component in the trolley!
We consulted with a bearing specialist from Schaeffler (a German bearing manufacturer) and their recommendations enabled us to select the most suitable bearing for the Zippey. The bearing also has a specific seal type (recommended by the Applications Engineer), to reduce the effect of corrosion. The use of this specific seal means that the Bearing doesn't need to be maintained or re-greased.
The bearing has an RPM (also known as 'Limiting Speed') of 20,000rpm, which will allow an optimum max theoretical speed of 70mph/113kph (based on a wheel diameter of 30mm (1 3/16").
3. Wheels: The advice from the bearing specialist also confirmed that the bearing housing (the wheel), should be of a sufficient hardness to support the bearing. We have therefore increased the hardness of our wheels, so that they are hard enough to resist any deformation during use and to provide adequate support for the bearing. We have switched to a special type of Stainless Steel which provides an outstanding combination of high strength and optimal mechanical properties, suited to the typical range of operating temperatures. This material also provides excellent corrosion resistance. Although in very harsh environments, it may gradually develop overall light rusting and pitting, this superior material is vastly superior to the standard Heat-treatable Stainless Steels.
As part of the design review, consultation with wire cable specialists and LEEA, lead to a consensus of opinion that the harder wheel material would not result in a detrimental effect on the wire cable- in fact, the hardness of the new wheels is still comparable with competitor trolleys.
The new wheel material is designed to be factory-hardened, as the material must be hardened after the machining process. This hardening process results in an iridescent (purple/bronze) coloured finish to the surface of the wheel. This is a normal effect of this superior material and treatment.
The integral design of the Zippey remains unchanged and we're still using a double row of bearings for stability during flight, (single bearings can cause the trolley to try to climb the cable which results in uneven wear to one side or the other).
Other upgrades to the Zippey Range include:
NEW Bumper Material
Flat end bumpers are now made from an impact resistant Polymer which has significantly increased the wear resistance when impacting an end stop/braking system.
Improved Gate-closure Spring
The new design of the Stainless Steel gate-closure spring offers improved durability/life span, whilst offering the same, positive functionality allowing the Zippey to be easily mounted/dismounted.
Re-greaseable Version DISCONTINUED
The version with the greaseable bearings have been made obsolete by the above improved bearings & seals and will therefore be discontinued.
NEW Bumper-mounted Grab Bracket
We will be launching a version with bumper-mounted grab bracket, for use with Trolley-retaining braking systems...coming soon!
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