Specifications and Use
Netting Placement
There are four 190 foot long nets connected between the two stands. There are two on the sides oriented vertically and connected to the upright supports. These two nets are connected at the bottom just above the bases of the stands and stretch four and half feet up the upright supports (figure 4). Another net runs the length of the longer of the two angled beams and is 12.5 feet in length, while another runs the length of the shorter angled beam at 10.6 feet. There is netting attached to cover to the two triangular sections at the top of both stands (figure 5). The Main Stand has netting secured to the large rectangular gap between the two upright supports. The Roll …show more content…
The nets on the top protect from downward falling hail and are angled at 25 degrees and 20 degrees respectively in order to prevent hail buildup (figure 1) (Appendix X: Prototype Sketches).
Materials
Steel was chosen over other materials such as wood, aluminum, or other metals for three main reasons: weight, strength, and cost (Appendix X: Materials Research). The weight of the material used was a key factor in choosing steel. The device needs to have a low center of mass to avoid instability during high winds tip over in winds. The high wind loads required a material with high strength in order to withstand constant and high forces. The nets will be deployed over a great distance which is similar to having a great sail outside during a storm. Going forward there may be components that could be replaced with plastics to lessen weight. …show more content…
Wheels
Figure 7: The final design casters are air ride tires to allow for easy roll out.
Specifications and Use
There are a total of eight wheels per device - four on the Main Stand and four on the Roll Out Stand. Each wheel has a diameter of six inches, and is omnidirectional. The wheels are steel plate casters with air ride tires (Figure 7).
Rationale
There are four wheels for stability - one on each corner of the base on each stand. The size and material of both the wheels and casters is to accommodate the considerable weight of the structure they will be supporting.
Cable Crank System
Rationale
To reel in the cable when the device is being retracted, or to hold tension the cables in order to hold the shape of the netting, the Roll Out Stand has a system to hold the cables taught. For the prototype, the ten cables are brought together by a four inch diameter wood pipe. The cables are then pushed through a one foot section of a beam and tied off. This prevents the cables from sliding back through the ring or becoming tangled. Future design developments should explore installing a motorized crank system to expedite the deployment process ( Further Development