1. Apr 6, 2012

### frenchw

Ok This is a long question so bear with me. BACKGROUND: I am designing a set of crush drums that counter rotate (similar to a rock crusher). One Drum is adjustable to increase/decrease distance between drums. Each drum is 170mm in diameter, 200mm long, made from 10mm thick steel. They are chain driven by a 0.75hp motor (550w, 50hz, geared down from 1400rpm to 155rpm)

Ok so this is where it takes some imagination, If you could please tell me what I am missing and if I had it how to carry out the equation.

I want to find out:

- what the maximum force the drums could take without jamming

- Torque (the original rpm was 1400 but from a series of sprockets the rpm is now 155)

- What force is exhorted by the drums

I have blades on my drums. One drum can be adjusted on the x axis. How does this affect my equations.

Could someone please take their time to explain this to me. Attached is a 3D pdf of my CAD. The belt and pulleys represent chain and sprockets

Extra Info: Each drum is welded onto a 350mm steel axle with a diameter of 25mm. Each drum has a 10mm thick plate either side with a 25mm hole in which the axle passes through. The axle sits in a heavy duty flanged bearing. The way the drums are powered are by sprockets and chains in the exact same layout as this charcoal crusher http://www.wolterpyrotools.com/image/charcoal_crusher_2000.jpg except instead of a handle, another sprocket leads a chain to the 0.75hp motor

Regards,

Will

2. Apr 6, 2012

### OldEngr63

Will, I did not find you CAD drawing. Was it attached?

3. Apr 6, 2012

4. Apr 6, 2012

### OldEngr63

Do you intend to have the two drums in contact as you have shown them,, or will there be a gap between them? How large will the pieces be that are being crushed compared to the drums?

5. Apr 7, 2012

### frenchw

The crush drums are adjustable, Minimum gap 20mm and largest gap 70mm. They are crushing bags of suger (500g, 1kg and 2kg bags).

Will