Senior Project

Design Issues

The first issue to overcome was the size of tubing required for the center stand. Since the center stand would be subject to multiple moments and compression forces, the proper selection was critical. The failure of this part would be a catastrophic failure.

 

The next design issue was the length of the base feet required to support the system. The base needed to be wide enough to support the brew kettles and shelves but also short enough to not be in the way or become subject to excessive moment forces. The base also had to support the center stand and shelves when in the folded position.

 

The final design issue was the hinges and locking pins for the base. Multiple iterations of hinge designs were used to find the currently successful design (Figure B.14, B.15, and B.17). The design had to hold the legs in place under a large static load including a safety factor as well as be commercially available and cost efficient. The current design will allow cost to be reduced without sacrificing safety.

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The part the most easily passed the analysis was the size of the project. A 28 by 28 inch base (when collapsed) was a design requirement that needed to be met to allow for easy storage. This was easily met with the 25.4 by 25.4 inch base.

 

Calculated Parameters

Appendix A shows the calculations required to ensure a successful brewing stand. The calculations determined to solve the above design issues are shown below:

• 1.5 inch by 1.5 inch by .24 inch thick square tubing to support shelves and kettles (Figure A.3-A.6)

• 50 inch by 50 inch total base width when extended

• 28 inch by 28 inch base width when collapsed

• Heavy duty hinges with .125 inch diameter pins to support base legs (Figure A.8)

• Steel locking pins to secure base legs of .125 inch or greater (Figure A.8)

• Total rack weight of 96.79 lbs (Figure A.16)

• The tree will not flex more than 1 degree for each shelf (Figure A.5-6)

The system was designed using the required 1.2 Safety Factor and then the next largest available size was selected (Figure A.1)