Mechanical Eng. Design Project Help

[aszedlar1]

I am currently a junior IE major at Florida State University. I am in an intro to ME class where we are to design a dumping device and could really use any suggestions on how to achieve this. The problem and specifications are as follows: <br>
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Industrial waste is transported in dumpster carts to a centralized garbage bin. Each dumpster cart has the dimensions of 4ft wide and 3ft in height. The max. wieght of each cart and its contents should be 500lbs. The dumpster cart needs to be dumped into a large recepticle, <br>
which is located much lower in the ground in front of and below it. A worker is able to apply a force of 20lbs onto any handle designed to aid in dumping out the cart. Ultimately design a mechanical means by which to <br>
tip the cart and allow its contents to be emptied into the bin below it. Discuss the safety and reliability of your solution and its use.<br>
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Any help/suggestions on a method by which to tackle this problem would be greatly appreciated. Again - remember i am only a junior in college - and really do not feel i have a good enough background through 1/2 a semesters class to complete this on my own. Thanks - Amber ;-)

 

[ecampos]

Since you do not give any size restrictions the simplest way would be to use a lever. If we make a couple of assumptions: 1. The base and wheels weigh 100 lb. there by leaving the weight of the bin and garbage equal to 400 lb. 2. The cart will empty if tipped to 45 degrees.<br>
If the cart tips over on the front wheels then the bin and garbage are applying a 800 ft-lb torque. This is what you need to overcome. Then a lever applied at the center under the bin, the fulcrum or pivot 1 foot away from the center of the bin and opposite the dumping side and then a 40 foot length of beam would get you enough force to lift it excluding friction. You would probably need a little more length to actually move it. So if you use a lever with a 40 to 1 ratio and apply 20lbf moving thru 45 degrees it should work.<br>
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Any more help?<br>
let me know

 

[aszedlar]

Ecampos,<br>
Thank you for your suggestion. I am planning on using that as one of my alternative options to help in solving this problem. However, as far as the reliability issue is concerned i think that this may not be as reliable as perhaps using a pulley. I was wondering if i placed a pulley above the dumping side of the cart and then pulled it from the back side of the cart if that would work. I know it would tip the cart over and into the bin - provided i used your assumption #2. Does this sound like an appropriate method? If so, what sort of calculations woud this entail - as we have only breifly studied pulleys. Thanks for your help! ;-)