When JCB, the global manufacturer of construction machines, identified a need for a steep improvement in the performance of their hydraulic cylinder sealing systems, Hallite Seals were given the opportunity to provide an engineered solution for this demanding requirement and they responded immediately with their snap-in Type 844 wiper made from high-performance Hallite® 361 polyurethane.
JCB construction machines work extremely hard in arduous and highly contaminated conditions. Therefore it was identified that no ingress of contamination was acceptable into the sealing system, to achieve this goal the new wiper seal was developed. The rod wipers’ function is to ensure that no ingress of dirt, moisture or any other contamination enters the cylinder which can cause serious damage.
The double lip design of the Type 844 has a special feature of a flap on the external wiping lip which covers the gland housing. This flap prevents the water/slurry trap occurring which is so common with conventional wipers and thereby stops contamination from getting around the outside of the wiper.
The wiper showed its ability to clear surface frost/ice whilst operating at temperatures down to -45°c and also working in environments of 110°c radiated heat.
Results of initial in-house tests were so encouraging that JCB engineers took the decision to install the wiper in the glands of the bucket and leg ram cylinders, the two areas which are the most arduous and highly contaminated. Extensive field trials were conducted and the Hallite wiper functioned perfectly outperforming all other competitors’ designs.
The success of these trials and the performance of this product have led to the Hallite T844 wiper achieving engineering sign off across all JCB equipment.