On 5 Jun, our risk assessment finally got approved! YAY!!
To us, bastions of safety and wellbeing, this was a crowning achievement.
This meant the procurement of the safety paraphernalia. We went to look for safety boots online. We found some pretty-looking safety boots on Amazon. However, Tony, our experienced 5th to 10th member,said that safety boot sizes can be quite different from our normal shoe sizes, and recommended us to buy them in person. When we borrowed safety boots from SMRT for our Tuas Train Depot site visits, we also felt that the safety boot sizes are usually larger than normal shoe sizes. So we decided to buy them in person instead.
However, we faced lots of problems. Places selling cheaper safety shoes did not seem to have a retail or outlet store where we can try them out. We discovered that Timberland sold safety shoes, however, they were really pricey, at about $200 for a pair. A whooping $800 (about half of MnT budget) to buy shoes for all 4 of us.
hmmmm, how?
Also, we are reconsidering our first lifting design which has an extruding arm and worm gear. Worm gears, those in our price range at least, are too weak to lift the heavy load of the lifting arm and the unit, with a maximum torque of about 60-100Nm.
Hence, we decided to use linear actuators. They are much stronger and can exert a lot more force at about 3000-5000N. This meant that the linear actuators is more likely to be able to lift the lifting arm and the unit (to be substantiated with calculations soon).
The drawback of using linear actuators is the decrease in the rotational ability (directly translated to mobility in our first design). To counteract this, we will use a configuration of 2/3 arms connected with linear actuators. To preserve the high mobility of the clamping system, we will still use a ball socket joint between the lifting arm and the clamping system.