Max static force a rock drill/jackhammer can provide

[Mechy011235813213455]

Hi,

I am working with the idea of using a rock drill or jackhammer for vibrating a heavy object. I'm not very familiar with pneumatic systems so I'm having problems determining the max static force one of these could provide. For example say with a weight attached above it, so it's supporting the entire weight, though that's probably not how I would configure it. Just clarifying that this is not impact force but an attached weight.

Looking at a drill like this Grainger Air Rock Drill I've guess-timated that the max static force would be the PSI provided times the bore size, or 90 PSI * 4.91 In^2 = 441.8 Lbf in this case. Is this a reasonable way to estimate it? Or is it more dependant on the air compressor supplying the pressure (IE can the compresser keep up 90 PSI with a heavy load).

I'm not looking for exact calculations just help with understanding the general concept.

Additionally does anyone have any idea if a drill like the one I linked uses springs for the return stroke or if it's powered by the pneumatic system. My impression was that the pile driver is powered pneumatically while the bit returns to position by a spring. This would mean I couldn't rely on the hammer for much of a return force at all.

Thanks,
Mechy011235813213455

 

[hydtools]

It is not a good idea to use an impacting device to provide just vibration. The impact energy will be absorbed by the chuck end or internal choke and lead to self destruction. A rock drill or breaker are meant to hit and break something, either rock or itself. The item shown in the link uses the compressed air to return the piston hammer, not springs. The bit, or rather the breaker, is returned to impact position by feed force applied by the operator pushing on the handles.
Consider, instead, a vibratory device like those used to shake rock crusher bins or dry product bins.

Ted

 

[IRstuff]

What is weight of the object? Can you use a shaker head:

http://www.modalshop.com/excitation/excitation.asp?P=110_lbf_Dual_Purpose_Shaker&ID=307

http://www.etssolution.com/shaker-l215m.php

http://www.labworks-inc.com/general_purpose_systems/lw127_123-500.htm

Is it a single frequency? If so, there can be some reduction in volume relative to a standard head.

TTFN
faq731-376

 

[Mechy011235813213455]

@hydtools - Thanks for the information. I agree I would prefer not to use an impact tool like a rock drill but it is what I was told to investigate, though most likely I'll end up recommending something else...

@IRstuff - I'm in the process of finding the weight of the object myself but it is considerable, it's cylinderical, mostly steel, approximately 1 ft diameter 6ft long, and somewhere around 750-1000 lbs. So I don't think it would fit in one of those shakers (I saw those before and I'm assuming you place items inside of them).

 

[Mechy011235813213455]

Looking more closely at those shaker heads I'm guessing you don't put objects inside of them. I definitely will look into using one of those.

 

[IRstuff]

yah, on top.

THIS one is rated at 77,000 lbf:

http://www.etssolution.com/shaker-mpa3798-h3580a.php

Given your description, a jackhammer probably wouldn't have budged your object much.

TTFN
faq731-376

 

[hydtools]

The drill would have made one heck of a racket, though.
Static force is hardly the description I would use for the output of a dynamic reciprocating device. Force amplitude maybe.

Ted