Recent content by Philip Potts

Thanks, Randy, now that you mention it I too have see the trap/plate thing at buffets and such. As I remember an employee would just drop a stack of plates in and then they would rise as each customer took a plate. This is the exact same thing I would like to do.

Thank you Randy. You have given me some very useful information. I am familiar with parallel and series circuits in electrical systems but I did not realize this also applied to springs. I didn't give too much detail about the object because I didn't want to clutter things up. So this seems...

How so? Wouldn't two 10" springs be the same as one 20" spring? Also, for my project the object weighs three pounds and is eight inches tall. This gives a spring rate of 0.375 pounds/inch. I assume that this would be for one spring. If I were to use four springs, one at each corner, would I...

JBA: Yes, all the objects are the same weight and height jrmichler: Thank you so much. With the information you supplied this might be easier than I had hoped.

I have been searching but I have not been able to find the information I am looking for. I want to build a "floating table" that is supported by one or more compression springs. When an object is added the table will lower by just a bit. As another object is stacked on top of the first one...

The symmetry was planned because I don't want the levers to extend beyond the sides of the cart when in motion. When the ramp is in the down position it is OK for the lever to extend some but when the ramp is in the up position the cart will be towed across the plant and I don't what the arm to...

Yes indeed. The pulley diameter is 2.68 and the distance between pulleys (center to center) is 4.75.

Hi Dr D, Thanks for responding. I have added dimensions to the drawing. I'm still in the planning stage so none of this is set in stone. My main goal is to provide a way to lift the ramp by the average person. As designed the ramp weighs 84 pounds. I can get that below 55 if I switch some...

Yep. I was thinking about adding a spring assist. Thanks.

And that is the vertical component of the tension in the cable, so the tension in the cable is considerably greater. If the distance from E to the lower roller is 16" like DE, then the tension in the cable is this 79 divided by 0.71 , some 111 Lbf: Thank you BvU, I was really off with my...

Hi BvU, Thanks for the greeting and your response. I have added some labels to the diagram to make communication easier. I used the formula for a Class 3 lever of Mechanical Advantage = d2/d1. I got d1 by measuring from point E to the tip of A. Then d2 by measuring from point E to point D...

I have been asked to build a cart that can be pulled by a tugger. (A tugger is a small stand-up vehicle.) The cart has to have a ramp to push other wheeled carts up onto the tugger cart. The photo below gives an idea of what I have come up with. The ramp on the left side is 30 inches from...

Hello All, My name is Philip Potts. I am a 62 year old maintenance mechanic in a factory that stamps metal parts for the automotive industry. My background in physics in nil. In fact, my math background is high school algebra and geometry. Part of my job is to design and build tables, carts...