Monday, 1 March 2010

Leg strip down begins.

Seems like we are going backwards, but we had to completely strip the leg down in order to make various changes that we hope will improve performance. Both Josh and I found the task of having to strip and re-build the leg somewhat daunting.. but it has to be done!

First we took the three low friction hydraulic rams off the leg, ready to have the selas replaced with the standard frictions versions. According to Parker this should help us with air in the rams, which we have been having problems with. At the same time all the ram rod end spherical eye bearings are being replaced with maintenance free PTFE on steel type, to reduce mechanical play in the system.

We are also replacing the majority of the IGUS bearings on all of the main joints, with maintenance free PTFE on steel bearings. Again this is to get rid of much of the mechanical play caused by the sloppy fit in the IGUS bearings. For this sleeves have to be made in order to get the new smaller bearings to fit into the IGUS bearing holes.

Finally we are replacing our standard two wire braid hydraulic hoses with a lighter weight polymer version called Flexor 7. This is a bit of a gamble, as we don't know anyone with experience of these hoses, but a according to the spec. sheets they are rated for our application, and will save us 45Kg overall in machine weight, which is not to be sniffed at!