Today, we plan to build a base for our lifting arm. But first, we will discover the CG of our arm. We require the CG of arm to ensure that the far edge of the base (pivot) is beyond the CG of arm such that our lifting arm will not topple over when mounted to the base.
Without the weight of actuators and worm gear, we derived that the base must be at least 1.62m long from the support tower to prevent the lifting arm from tipping over.
We plan to attach heavy-duty wheels to our lifting arm base, so that we can move our lifting arm and use it as a trolley too. This means that the point of contact that front wheels have with the ground must be at least 1.62m away. This may make our base quite large.
Alternatively, we consider having 2 3060 aluminum profiles to act as the support tower. If we approximate the weight of the actuators and worm gear as 2kg and 0.7kg respectively and include them in our moment calculations:
With a support tower reinforced with another 1.5m 3060 aluminium profile, actuators and worm gears, we calculated that the front wheels must be at least 1.13m away from the support tower to prevent the lifting arm from tipping over.
To increase the safety of our design, we can have base with front wheels about 1.25m away from support tower. The back wheels of the base can be about 0.15m away from our support tower. This effectively means that the distance between the front and back wheels of our lifting arm will be about 1.4m apart and the length of the base can be approximated to be about 1.5m long to accommodate for wheels placement.
The width of our base can be about double the width of our lifting arm at its widest point, with the front and back wheels placed just within the sides of the base. This should ensure that the CG of our lifting arm will be within our base, as well as provide enough breadth to place pneumatic units on the base.
Also, by balancing and adjusting the pneumatic unit on a 3060 profile, we approximated the Centre of Gravity of the pneumatic unit, as seen in the picture below. This centre of gravity will be kept in mind when we design the clamp system and the distribution of the clamps along the aluminium profile.
We also designed and 3D printed a mold for one of the attachments on the base, seen below:
