Re: Excentric Shaft Offset
Dear Mr. Jose Martinez,
As you know, there are two types of vibrating mechanisms. One is like circular eccentric as is being used in reciprocating feeder. In this case, the shaft with the eccentric is mounted on a fixed structure and eccentric is connected to the vibrating tray. In this kind of mechanism vibrating stroke is two times the eccentric radius.
Other arrangement is rotating imbalance weight mounted on the tray itself. In this case, rotating imbalance weight imposes forced vibrations to the tray. Its stroke magnitude is related to the magnitude of imbalance force, total mass of the tray plus material and spring stiffness. The imbalance mass could be one or two with angular phase difference, etc.
Regards,
Ishwar G Mulani.
Author of Book : Engineering Science and Application Design for Belt Conveyors.
Advisor / Consultant for Bulk Material Handling System & Issues.
Email : parimul@pn2.vsnl.net.in
Tel.: 0091 (0)20 25882916 ■
Re: Excentric Shaft Offset
Yes, we are goig to use the first system were the shaft with the eccentric is mounted on a fixed structure and eccentric is connected to the vibrating tray and the vibrating stroke is two times the eccentric radius.
Our question is mainly what is the offset we should give the machined shaft. This is the distance between the center of the 2 excentric circles.
We are thinking in the range of 3/16" since we are looking for vibration and not too much up and down movement. Also we do not want a large imbalance in the excentric shaft which the fixed struture is going to have to absorb, but we really do not have the experience in knowing if 3/16" to give us a total stroke of 3/8" is enough or if it is too much.
Does anybody have experience with vibrating conveyors that can give us an idea of what actual offsets are used in applications involving scrap metal. ■
Scrap Screening
TRY CONTACTING.............. a company in CHICAGO, USA
called........GENERAL KINEMATICS........ or G-K
www.generalkinematics.com
These people have the specific knowledge to guide you on scrap metal screening eccentric offsets you need. EXPERTS on scrap screening technology.
Sincerely, George Baker ■
Re: Excentric Shaft Offset
Dear Mr. Jose Martiez,
Mr. George Baker has already given you one suggestion.
In addition to my earlier reply, the stroke and frequency depends upon the type of screening or material characteristics. If one is not sure about the desired result, then, one option is to have variable speed drive motor so that one will have the option to choose the frequency of vibration which will give the best result. In general, finer the material, smaller will be the stroke and higher will be the frequency i.e. for coarse material, lesser will be the frequency and more will be the amplitude.
If you wish to have provision for change of stroke then, you have to key the eccentric disc on the shaft, wherein one would require to change the eccentric disc for changing the amplitude (instead of full shaft).
Regards,
Ishwar G Mulani.
Author of Book : Engineering Science and Application Design for Belt Conveyors.
Advisor / Consultant for Bulk Material Handling System & Issues.
Email : parimul@pn2.vsnl.net.in
Tel.: 0091 (0)20 25882916 ■
Scrap Conveyors
if you are conveyor scrap from A to B and wanting to separate over a perf plate opening.
This reciprocating type of conveyors , normally flat or horizontal on leaf springs or coiled spring setup typically have a 1" throw in them to move the material from feed end to discharge end.
George ■
Did We Ever Get The Problem Solved?
Let me know please.
Thanks kindly, George Baker ■
Eccentric Shaft Offset
This may be of help
If you go to www.rosta.ch and navigate your way to their catalogue (oscillating mountings) - page 52 (crankshaft driven calculation) - there is a simple graphical solution for theoretical material velocity v various crank radii and rpm. ■
Excentric shaft offset
We are proyecting in buiding a vibrating conveyor to sort scrap metal from dust and move it at about 200 ft/ min, but do not know how to calculate the desired stroke to be determined by the offcenter machined into the excentric shaft.
On your experience what is the offcenter machined into the excentric shafts in this type of conveyors?
Any input would be appreciated.
Jose Martinez ■