Introduction! and How Umbrellas Work

Hi! My name is Sarah Min. Engineering and product design are completely new topics to me but I’m hoping to learn a lot about them in this course. I’m the kind of person who’d be perfectly content never seeing a math equation again in her life but the various applications of this course as well as the hands on nature of it really intrigued me which is how I ended up taking the class.

The product I chose for the pre-assignment is the umbrella. I chose the umbrella for a number of reasons, one being that I am very grateful for it. Being able to walk outside while it’s raining and not getting completely wet is really great. It’s also quite handy. It can expand easily into something big enough to keep me dry and then fold back into something small enough to fit in my purse. Also, if you are in possession of an automatic umbrella it’s great because you can open it with one hand! Another reason I chose the umbrella however is that there are quite a few things about it that I find quite irritating. For instance, it’s pretty useless when it’s raining hard. It keeps the top of my head dry but that’s pretty much it. My feet get soaked as do my legs and water droplets obscure my vision as they get flicked onto my glasses. Not to mention when it’s windy in addition to rainy, the umbrella gets tossed around in the wind while I’m just trying my hardest to keep it from flipping inside out. Umbrellas are also fragile. Bend one of the spokes the wrong way and it breaks instantly and you’re left with something that looks like a sad bat with a broken wing. In addition, something that befuddles me about the umbrella is how we can live in a world so technologically advanced that the average person can enjoy the wonders of an iPhone but still have to deal with getting their shoes wet when it’s raining. Why is it that no one’s come up with a new and improved version of the umbrella? One technical question I have about it is how exactly do the umbrella spokes stay open and closed?

In order to understand how the spokes of the umbrella stay open it would be best to become familiar with the basic structure of the umbrella. The key components to any basic umbrella are the shaft, the ribs, the stretchers, and the canopy. (Different variations of the umbrella such as collapsible umbrellas or automatic umbrellas differ in some respects to the basic stick umbrella but all have the same basic design.) The shaft is where people hold the umbrella and it is connected to the stretchers which are metal rods that are connected to the ribs and allow the ribs to extend as the umbrella is being open. The ribs are the framework for the canopy of the umbrella and are what helps the umbrella keep its shape. The ribs are attached to the top of the shaft by fitting into a top notch and the stretchers are connected to the shaft by an either plastic or metal runner. The runner slides along the shaft of the umbrella as it is being opened or closed. The ribs and stretchers are then connected with joiners, or small jointed metal hinges, which open or close as the umbrella does the same. 

When you want to open the umbrella the runner moves up the shaft which extends the stretchers which in turn extend the ribs. This opens the canopy and in order to keep it open the runner catches on the higher of the two catch springs of the umbrella. The lower spring keeps the runner from sliding up when the umbrella closed. These springs are pressed down when the umbrella is being opened or closed.

So in response to my initial question, the umbrella keeps it shape because the spring catches the runner before it can slide back down. The runner in turn then holds open the stretchers which are connected to the ribs of the umbrella. 

Sources:

http://www.madehow.com/Volume-1/Umbrella.html

http://online.wsj.com/article/SB10001424052748704912004575252193811841662.html

http://www.umbrellaman.co.uk/page/parts-umbrella.htm