Everyday

All posts tagged Everyday

Open Mind: L’agrafeuse (The Stapler)

Posted by Abraham (Team UV) on December 28, 2014
Posted in: Open Mind. Tagged: , , , , , , , , , , .

Staplers. Photo Credit: Staples-3p.com

The word “engineer” can mean a lot of things.  The word “engineering” can mean even more.  Both words can be hard to relate to especially if you haven’t studied or practiced the discipline.  However, it is often easier to relate to these and similar words by examining a tangible example.  Many of the things we use everyday utilize multiple principles of engineering that most simply overlook.  I am here to put a mini-spotlight on just one: the trusty stapler.  We all know what a stapler does and how it works but what “engineering” principle went into the bringing of our powerful and hinged friend to life, figuratively speaking of course.

Good ‘ole vector statics comes into play in the form of a spring interacting with loaded staples.  When the stapler is closed and not moving, an extension spring is elongated usually inside the hood of the staple chamber and provides a component of force in the direction of loaded staples.  When you staple together your 20 page single-spaced research paper on naturally occurring composites, this force component slides the next staple into position ready to staple whatever other monstrosity of a report you may have lying around.

The stapler is a machine so it would be smart to assume that machine design and stress analysis are heavy hitters in the world of staplers.  Individual staples are easy to remove from one another and that is because they are held together by a weak adhesive.  This weak bond is important because if it were too strong, the staple would never succeed to touch the surface of your 40 page chemistry lab report that you worked on all quarter.  This bond between the staples has to fail in shear, so the bar that comes on top of the staple must provide enough stress at the bond to shear away the staple from rest, through the thick stack of pages, and onto a low friction finish plate that bends the tips of the staple around the last 9 weeks of your life.

The last but definitely not the least of the engineering principles embedded inside the stapler is material science.  When staples are purchased from your local stapler and stapler accessory store they are straight and bent at 90 degree angles on both ends.  After being used on your 110 page Matlab project report, these angles can change to 180 degrees or more.  Strain hardening occurs at the bent sections of the staple after being used which provides a more secure hold on the pages of which your deepest and most profound thoughts are printed upon.

It is important to keep in mind that the things we buy off the shelf don’t simply appear magically.  Even the simplest of these things go through myriads of engineering principles before it’s ever machined or even designed.  Just keep that in mind next time you’re using your cellphone or opening a door or even putting on your shoes.

The Brief Breakdown of a Simple, Everyday Item

Posted by Andrew (Team UV) on December 14, 2014
Posted in: Open Mind. Tagged: , , , , , , , , , , .

Although most people I know use mechanical pencils, traditional wooden pencils are still as important today as when they were first introduced.  Wooden writing utensils are still used in compasses and colored pencils which means they will continue to need sharpening.  Before receiving this prompt, I never realized how complex a simple wall or desk mounted sharpener really is.  As a kid, I would utilize the class sharpener to avoid boring lessons or to talk to my friend but didn’t know the engineering involved to make such a device work.  I’m not talking about an angled sharpener but rather a planetary sharpener like shown below:

Planetary Sharpener with External Case Removed. Photo Credit: Wikipedia.org

 Planetary sharpeners installed in classrooms or offices in the 60’s can still be found in fully functional form.  These things were designed to take abuse, misuse, and to stand the test of time.  Taking a look at a mounted sharpener I was able to come to three engineering conclusions…

  • Planetary Sharpeners must be designed for ease of use

It’s safe to assume that a sharpener is going to be used by both adults and children at some point in its life cycle.   This means that a designer needs to ensure that a child can apply sufficient force to crank the mechanism with ease.  If this condition isn’t met then the market for such a product would become limited to adults working in office settings.

  • Material selection is key

As stated above, planetary sharpeners can be found in perfect working order even in run down and abandoned buildings who have gone years untouched.  I attribute this to great material selection.  Most sharpeners are manufactured out of steel which has been hardened to resist wear and deformation.

  • Planetary Gearset

Lastly, if you have ever taken the case off of a mounted sharpener, I’m sure you’ve seen the cutting cylinders used to sharpen.  The internal mechanism is basically a planetary gearset.  A sun gear is usually centered in the middle of the train with planet gears connecting it to an outer ring.  This allows the center of the outer ring to revolve around the center of the inner ring or vice versa.  In the case of a sharpener, the inner sun gear is replaced with the pencil and the connecting planetary gears are replaced with rotating cutting cylinders.  These helical cylinders are designed to cut and are angled to form a point which also forms the point of a pencil.  More information about planetary gears can be found here.

Planetary Gearset. Orange Sun Gear, 3x Teal Planetary Gears, and Blue Outer Ring Gear. Photo Credit: Reddit.com

Whether it be a door handle, a cup, or even a pencil sharpener, it’s sometimes easy to dismiss the complexity of our everyday products.  The beauty of engineering is taking a complicated task and making it routinely easy for anyone to do.

 Until next time!

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The Complexity of Door Lock Design, Not So Simple?

Posted by Ketton (Team UV) on November 16, 2014
Posted in: Open Mind. Tagged: , , , , , , , , , , . Leave a comment

Door lock. Photo Credit: MadeHow.com

I am more than positive that you come in contact with a a door at least once a day, right?  Whether it be turning the handle or putting your key in the slot and unlocking the door so you can go inside.  Have you ever realized how much design and consideration goes into that door lock?  A door lock is much more complex than one would have thought!  Most of the locks you see today are pin tumbler locks.  The pin tumbler lock uses a set of pins to prevent the lock from opening unless the correct key is inserted.  The key has a series of grooves on either side of the key’s blade that limit the type of lock the key can slide into.  As the key slides into the lock, the horizontal grooves on the blade align with the wards in the keyway allowing or denying entry to the cylinder.  A series of pointed teeth and notches on the blade, called bittings, then allow pins to move up and down until they are in line with the shear line of the inner and outer cylinder, allowing the cylinder or cam to rotate freely and the lock to open.

Let’s take a look at the design process for this type of lock.  First off, these locks have several small static and dynamic parts.  If one of these parts are not correct the lock will be useless.  Take note that some of these parts are the size of a penny or even less!  This is where Geometric Dimensioning & Tolerancing (GD&T) comes into play.  GD&T is a process for dimensioning drawings and is standardized throughout the engineering industry!  In addition to this, material selection is important.  When a metal comes in contact with a different metal this increases the rate of corrosion.  Since we have to use the key and lock combination at least once a day if the wrong materials are chosen at some point the “rust” developed on your key or inside the lock could become too much to even fit your key in there!  Lastly, the key; since the key must lift each pin a different height.  Each pin is connected to a spring of a certain spring constant (stiffness) and each pin is a different length.  The key must be correctly designed in order to lift several pins to the correct height allowing you to rotate the cylinder and open the door.  Several mechanical actions are happening within the lock during the 2 second time frame as you unlock the door.  It’s amazing!

Can You Build a Better Mousetrap?

Posted by Ben (Team UV) on October 26, 2014
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Mouse Trap

Mouse Trap. Photo Credit: CottageLife.com

Even simple devices are feats of engineering evident in day to day life, from pencil sharpeners to staplers.  They have become so ingrained in the way that we look at the world that the curiosity and wonder has worn off.  These devices are so well made that it is almost impossible to ‘build a better mousetrap’; however this is worth considering.

The mousetrap is an incredibly simple device.  A block of wood with a spring, lever, and trigger mechanism.  When tasked with the removal of these rodents it’s hard to imagine the jump from a block of wood and some wire to a mechanism of mouse management.  The spring has to be strong enough to kill a mouse but not too difficult to set or too dangerous to leave lying around.  The wood block has to be cheap enough to mass produce on a large scale but still strong enough to hold the spring when it is loaded and released.  The trigger mechanism has to be sensitive enough to detect the nibblings of a small rodent but robust enough to allow the device to be moved without excessive misfire.  All engineering problems contain important balances like this and the best designs will prioritize these properties and deftly balance them in an accessible package.  The mousetrap has done this so well that the saying has stuck for decades.

If one were to attempt to build a better mousetrap one has to think of the drawbacks of the current models.  The classic mouse trap is a one time use, clean up can get a bit messy, and when they snap on your fingers they sting pretty good.  There are many designs out there working to solve these shortcomings, from poisons to frequency generators.  If you’ve been reading this blog you know that we like to speculate on areas for advancement in a wide variety of disciplines.  The vast majority of people are familiar with mousetraps and I would challenge you to comment any ideas that you might have for the future of the mousetrap.  How would you build a better mousetrap?