Precision ring slide keeps bespoke test machine on track

Based in Wakefield, Hedley Hydraulics started life as a system and component supplier to the UK steelworks industry and machine tool manufacturers. As the industry and technology have evolved, so too has the company and today it services a diverse range of sectors.

Projects have included a helicopter ship simulation deck landing pad, the Gloucester swing bridge and the Royal Opera House hydraulic stage set. And in 2003, the company launched its emergency National Hose Doctor Service, a 24/7 emergency mobile hose workshop.

The purpose of this customer's somewhat space-restricted system is to test adjustable mobile cartridge valves that are used in tractor transmissions. The machine adjusts the valve to different settings and then performs a series of tests to ensure it meets the end user’s specification.

With the help of technology specialist HepcoMotion, Hedley Hydraulics specified a Precision Ring Track PRT2 that rotates to adjust the pressure setting.  Indeed PRT2 was central to the viability of this system and to Hedley Hydraulics ability to meet this customer’s need for compactness. The company also ordered an LBG linear ball guide to clamp the valve into position. 

According to Hedley Hydraulics’ Steve Bottomley, the only other real alternative would have been to design the mechanism themselves, which was not quite the company's speciality. “The components HepcoMotion recommended have allowed us to keep the size of the machine down, allowing us to fit it into the small space envelope available,” he adds

The PRT2 ring slide and track system enables the creation of a limitless variation of open paths and closed circuits, and for Hedley Hydraulics it provided a neat solution: simple circular motion control at the periphery where it is needed and a hollow centre allowing easy access to the valve.

High build quality also ensures friction-free movement and this is enhanced by dedicated bearing design. The raceway conformity and low radial clearance are all optimised for continuous motion applications.  

As positioning accuracy is important in this application a rotary encoder was included to provide feedback on the angle of movement of the ring. The axial load on the ring is 100N and the rotation force required to turn the valve is 30Nm.

The HepcoMotion LBG ball guide provides the clamping rigidity necessary to prevent any movement of the valve during the adjustment process. The four row angular contact ball track has a number of benefits, including low friction, reduced differential slip and a high load carrying capacity in four directions.

According to Steve Bottomley, the components recommended and supplied by HepcoMotion are not only working well in the field, but have also saved his company substantial engineering time.