Jack hammers and their noise.

[nishantshivam]

Why do jackhammers and all other percussive drills make noise despite having a shock absorbing system? Why can't we design a structure that can get rid of the noise?

we can use, may in some ways, the conservation of energy law to make use of the sound energy and in turn gain more efficiency in the drilling process.

 

There's construction work going on in my neighborhood. Hence, this discussion.

 

[studiot]

The energy lost to sound is negligable in a jackhammer and inherent in the mechanics.

 

Muffler arrangements do exist, but they simply absorb the sound, they do not and cannot prevent it.

Having said that some hammers are noisier than others.

Edited July 8, 2015 by studiot

[swansont]

The energy lost to sound is negligable in a jackhammer and inherent in the mechanics.

 

Indeed. The mount of energy in what we think of as loud sound is amazingly small. 120 dB - pretty loud - is just 1 Watt

https://en.wikipedia.org/wiki/Sound_power

[iNow]

How much of the noise comes from the hammer itself and how much comes from the repeated impact it makes with the solid ground? Smash a flat shovel on the ground over and over and it will make a loud noise, and this is true no matter how well designed the shovel. Likewise with a framing hammer hitting a nail...

[Endy0816]

 

[StringJunky]

 

Yes! Erect vacuum tents over the work site, with the workers suitably attired, problem solved.

[Endy0816]

For every problem there exists an Engineering solution

[Enthalpy]

Most noise comes from the air exhaust and could certainly be reduced. You get an idea of the percussion noise by hearing a hand-held hammer drill (remembering the size ratio) or by hearing distinctly both noises.

Could the percussion noise be reduced too? Not so much if the tool must break hard material like concrete, for which peak force is paramount. In a first approximation, the shock of the piston on the hammer must be as hard as the target material. But with an adjustment, less hard parts would be used for asphalt.

In countries where jackhammers were recognized as harmful for the workers, disc saws replace jackhammers on most occasions, especially to open asphalt.

[Sorcerer]

This ties in a bit with my thread on piezoelectricity and roads, perhaps piezoelectric crystals could be used as shock absorbers, helping to dampen the noise and recover some of that (even if only slight) energy loss. I'm guessing this has been thought off and overlooked due to cost/benefit ratios though.

[Enthalpy]

If shock damping were acceptable for the function of a jack hammer, it would be easy to achieve by many cheap means.

But how to break concrete with a soft shock?

[Sorcerer]

Well if there is inefficiency in the recoil that could be used to generate current. Waste energy as noise is one of those inefficiencis, shock absorbed to the operators arms, not directed back to impact for breaking is another.

 

I know there is no such thing as perpetual motion machines, but there are maximum efficiency machines.

 

So why not transfer that ease energy to a more useful form and at the same time reduce noise and impact on the operator?

[studiot]

Here is the ultimate piledriver quieting system.

 

 

https://www.youtube-nocookie.com/embed/cFb0nLCKypg?rel=0

[imatfaal]

Here is the ultimate piledriver quieting system.

 

 

https://www.youtube-nocookie.com/embed/cFb0nLCKypg?rel=0

 

Love it!