Quick-locking bushes provide for rapid shaft/hub adjustments

Special locking bushes from ETP are being used by a manufacturer of PET blow moulding machines on the feed mechanisms. With outputs of up to 72,000 bottles per hour, any downtime on these machines is expensive. The bushes, which are used to mount the infeed and outfeed transfer wheels, give reliable backlash-free torque transmission. Should any adjustments be required, the single screw fixing of the ETP bush permits fast and accurate resetting.

PET (polyethylene therepthalate) bottles are blow-moulded on carousel-type machines, with the preforms supplied via an infeed transfer wheel and the finished bottles picked off the blow moulder by an outfeed transfer wheel. Customised ET_Express quick-locking bushes fix the infeed and outfeed wheels to their shafts and allow easy adjustment of the angular position and height.

ETP-Express backlash-free shaft-to-hub connections use internal chambers that are pressurised by a fastening screw; as the screw is tightened, there is an increase in internal pressure that causes the inner and outer walls to grip the shaft and hub, respectively. Positioning is easy to achieve, surface pressures are even and low (and non-damaging), and each bush can be reused up to 1000 times.

Custom bushes

To meet the application requirements ETP supplied a special locking bush based on its ETP-Express model to suit a shaft diameter of 40mm. Six locations in the flange of the bush were provided for the arms of the transfer wheel. To withstand cleaning, the bush was constructed from stainless steel. Reliable, backlash-free torque transmission of 500Nm was achieved, unlike the previously used mechanical connection with a polygon profile.

The ETP-Express bushes improve the accuracy of the feed because there is no backlash; downtime is also reduced by the easy single-screw setting that gives quick positional adjustment. Standard ETP products for shafts from 6-220mm are often available ex-stock.

Follow the link for more information and a short movie about ETP-Express locking bushes, which are available in the UK through Techdrives.

* [See also these application stories: Locking bush prevents damage in the event of machine jams and Locking bush is quick to release for machine cleaning - Ed]