It’s time we stop pretending like there is educational or scientific value to crushing things with hydraulic presses. I mean, yes they can apply thousands of pounds of force through hydraulics, but let’s be honest, we just like watching things go boom, and that’s okay. Now that we have come clean about the fact that we love destruction, we can move on to watching this video. In nothing but pure destruction, the Hydraulic Press Channel and the Slingshot Channel have teamed up to create a ‘rubberaulic press.’ Basically, this is a large solid metal rod attached to bungees that then smashes down on an anvil. The result is something you really don’t want to get your fingers caught in. Check it out.
The way that a hydraulic press and a rubberaulic press work are very different, but the result is some very smashed things. A hydraulic press exerts force through the conversion of hydraulic pressure into mechanical energy. A rubberaulic press, however, uses the elastic energy stored in the rubber bands to accelerate the bar down on the anvil. In other words, the rubberaulic press uses kinetic energy, and the hydraulic press uses hydraulic energy.
One of the coolest things in this video from an engineering standpoint is when you can see the base of press lift completely off the ground each time it is triggered. There isn’t a bounce to lift the press off of the ground, so what is making it lift up? Well, the tension forces become so great that the upward acceleration actually overcomes the gravitational acceleration downward. When released, the bands just want to expel their energy, whatever way possible, so when they can’t accelerate the bar downwards fast enough, the whole frame begins to accelerate upwards. This was obviously an oversimplified explanation, but if you draw out your free body diagram (yay physics!) it should work out.
[Image Source: Joerg Sprave]