Re: Safety Clutch On Stacker Slew Drive
Without understanding in detail, I appreciate the manufacturer's position for these (I am impressed they bought these up) and other reasons.
Again without knowing the details, off the top of my head maybe:
1. SELDA.
http://www.fairport.co.uk/selda-arrestor-safety-system/
2. Buffer / dash pot etc (probably not really the characteristics / reliability that you are looking for).
3. As a tangent of apparently where started an integral wet clutch etc (again, subject to maintenance / contamination - though maybe not as much etc).
Regards,
Lyle ■
Developing Issue
Hello Lyle,
thank you for taking interest.
Dear All,
The issue of fluctuation of frictional factor due to surface changes shall stand and will be discussed with preferred suppliers. The aim is / was, to keep the braking torque even with the safety clutch disengaged, and this has to be scrutinized also under a general safety point of view. In order to solve the technical issue, I shall pursue a controlled safety clutch, which would disengage in case of torque overload, but could be re-engaged by means of control. Thus, the case of a gust of wind --> re-engagement of clutch is a preferred feature could be distinguished from a safety issue (collision controller or safety alarm triggered), where disengagement of drive or brake torque would be essential. However, thus the simply mechanical safety device becomes a complex technical element to be correctly interfaced with overall control.
All comments are invited, especially opinions about safety in operation and also in the light of the KISS - principle.
Thank you in advance
R. ■
Safety Clutch on Stacker Slew Drive
Dear colleagues,
i work on a project where the client specifies a safety clutch, which shall not "release" in case of overload & engagement, but "hold on" with the setpoint limit torque. Intention is not to lose the brake torque (in a gust of wind, perhaps).
Usually however my design intention would be to release the boom completely, the safety clutch is a feature of last resort and when it is engaged the whole structural integrity will already be at stake.
Technically i found there's a type of friction clutch, similar to a multiple disc brake. However, the manufacturer said if used as safety device, due to long time state "out of operation" in the released position, the surfaces of the discs get tarnished and in the end the clutch will have a very much higher operating engagement torque (due to increased friction) than was previously set.
So, does anyone has experience with such kind of safety clutches and could please give me some clues from operation, or perhaps share ideas and technical opinions about the issue?
Thank you in advance
Regards
R. ■