Yorkman Posted January 21, 2020 Share Posted January 21, 2020 is it possible to reduce the throw of the generally available now servoless retracts? Edited By Yorkman on 21/01/2020 10:28:04 Quote Link to comment Share on other sites More sharing options...
Yorkman Posted January 21, 2020 Author Share Posted January 21, 2020 apologies for spelling of 'electric' in the title... Quote Link to comment Share on other sites More sharing options...
Martin Harris - Moderator Posted January 21, 2020 Share Posted January 21, 2020 Depends on your engineering/electrical skills. Most that I've looked at have limit switches and over-centre locks to protect the operating thread from damage and remove loads when up or down. Both aspects would need to be addressed. Edited By Martin Harris on 21/01/2020 10:36:16 Quote Link to comment Share on other sites More sharing options...
Bob Cotsford Posted January 21, 2020 Share Posted January 21, 2020 As Martin said, it's an engineering task. You could either make new trunnion blocks with an offset fork or new sideplates with altered distance from pivot to cam. The travel of the screwjack and height of cam cutouts to circuit board must remain the same in order to trigger the limit switches. Quote Link to comment Share on other sites More sharing options...
Yorkman Posted January 21, 2020 Author Share Posted January 21, 2020 I wonder how easy it is to adjust the limit switches? I want to reduce the 'up' travel.... Quote Link to comment Share on other sites More sharing options...
bert baker Posted January 21, 2020 Share Posted January 21, 2020 As I understand retracts, there not designed to hold the oleo and wheel up on the screw jack or to hold it down when deployed. they are mechanically locked up and down you need to study the mechanism to see how it works Quote Link to comment Share on other sites More sharing options...
bert baker Posted January 21, 2020 Share Posted January 21, 2020 You will hear the motor turning and for a short while nothing appears to happen,,;;;;;this is when the unit is unlocking or locking the unit Quote Link to comment Share on other sites More sharing options...
Bruce Collinson Posted January 21, 2020 Share Posted January 21, 2020 Simpler to cant the whole unit to the side slightly so the up clearance is improved, assuming that’s the plan? If locked out on down with minor canting, presumably the locked down would still be suitably aligned to track adequately. Just a thought. BTC Quote Link to comment Share on other sites More sharing options...
Yorkman Posted January 21, 2020 Author Share Posted January 21, 2020 Posted by bert baker on 21/01/2020 17:17:41: As I understand retracts, there not designed to hold the oleo and wheel up on the screw jack or to hold it down when deployed. they are mechanically locked up and down Indeed they are. I've just had a look inside a spare one I have, and sure enough it has tiny microswitches at each end of the screwjack travel. It would be possible to introduce something in there to activate the microswitch early and thus stop the movement but it would be very fiddly to do. I will carry on with them moving through 90 degrees. So, to answer my own question-yes, it's possible, but not very do-able Quote Link to comment Share on other sites More sharing options...
Alan Gorham_ Posted January 22, 2020 Share Posted January 22, 2020 80 and 85 degree electric retract units are available. Quote Link to comment Share on other sites More sharing options...
Bob Cotsford Posted January 22, 2020 Share Posted January 22, 2020 Posted by Yorkman on 21/01/2020 22:32:58: Posted by bert baker on 21/01/2020 17:17:41: As I understand retracts, there not designed to hold the oleo and wheel up on the screw jack or to hold it down when deployed. they are mechanically locked up and down Indeed they are. I've just had a look inside a spare one I have, and sure enough it has tiny microswitches at each end of the screwjack travel. It would be possible to introduce something in there to activate the microswitch early and thus stop the movement but it would be very fiddly to do. I will carry on with them moving through 90 degrees. So, to answer my own question-yes, it's possible, but not very do-able and not to be recommended! The locking action either end of the movement takes the strain off the screwjack location in the gearbox. Any excess load on the leg between locks can pull the threaded rod out of the gearbox leaving the leg flopping around, I've had a couple of units that it's happened to. Quote Link to comment Share on other sites More sharing options...
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