Already we learned that we can get more torque out of a motor by using one of two methods. In the first method we attach a gear train to the motor, then try different gear sizes until we arrive at the desired torque for the application. In the second method we eliminate the gear train altogether and…
Previously we analyzed the angular relationship between the Force and Distance vectors in this simple gear train. here we’ll discuss about commonality between the two gears in this train which will later enable us to develop individual torque calculations for them. From the illustration it’s clear that the driving gear is mechanically linked to the driven gear by their teeth. Because they’re…
In our previous topic we saw how adding extra pulleys resulted in mechanical advantage being doubled, which translates to a 50% decreased lifting effort over a previous scenario. Pulleys are engineering marvels that make our lives easier. Theoretically, the more pulleys you add to a compound pulley arrangement, the greater the mechanical advantage — up to a point. Eventually you’d encounter undesirable tradeoffs. We’ll examine those trade offs,…
Dynamic Lifting is Easier With a Compound PulleyIf you’ll recall from our last topic, Mr. Toga used a compound pulley to assist him in holding an urn stationary in space. To do so, he only needed to exert personal bicep force, F, equivalent to half the urn’s weight force, W, which meant he enjoyed a mechanical advantage of…
In this Topic series on pulleys we’ve gone from discussing the simple pulley to the improved simple pulley to an introduction to the complex world of compound pulleys, where we began with a static representation. We’ve used the engineering tool of a free body diagram to help us understand things along the way, and today we’ll introduce another tool to prepare us for our later analysis of…
Sometimes one of something just isn’t enough, like one potato chip, one glass of wine… And when it comes to lifting massive objects one simple pulley isn’t going to be enough to get the job done. Even the improved simple pulley, which we introduced last week, is often not enough, a situation which I’ve run across in my career…
Sometimes the simplest alteration in design results in a huge improvement, a truth I’ve discovered more than a few times during my years as an engineering expert. Last time we introduced the simple pulley and revealed that its usefulness was limited to the strength of the pulling force behind it. Hundreds of years ago that force was most often supplied by…
Lifting heavy objects into position always presents a challenge, whether it’s a mom lifting a toddler to her hip or a construction worker lifting work materials to great heights. During my career as an engineer I’ve dealt with similar challenges, some of which were handled quite nicely by incorporating a simple pulley, which we introduced last time,…
Last time we watched our example ceramic coffee mug crash to a concrete floor, where its freefall kinetic energy performed the work of shattering it upon impact. This is a scenario familiar to engineering experts who are sometimes asked to reconstruct accidents and their aftermaths, otherwise known as forensic engineering. Today we’ll take a look at what…
Last time we watched as the kinetic energy of our falling coffee mug was transformed into the work of creating a crater in a pan of soft kitty litter. Shock absorbing materials are often placed strategically to cushion valuable objects should they fall, and as an engineer I’ve sometimes had to implement break-its-fall solutions. Today we’ll place our mug into a less kind…