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elecrtic retracts

possible to adjust movement?

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Yorkman21/01/2020 10:27:12
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is it possible to reduce the throw of the generally available now servoless retracts?

Edited By Yorkman on 21/01/2020 10:28:04

Yorkman21/01/2020 10:28:50
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apologies for spelling of 'electric' in the title...

Martin Harris21/01/2020 10:34:22
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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

Bob Cotsford21/01/2020 11:35:07
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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.

Yorkman21/01/2020 15:28:00
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I wonder how easy it is to adjust the limit switches? I want to reduce the 'up' travel....

bert baker21/01/2020 17:17:41
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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

bert baker21/01/2020 17:22:26
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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

Bruce Collinson21/01/2020 19:40:54
558 forum posts

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

Yorkman21/01/2020 22:32:58
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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

Alan Gorham_22/01/2020 09:26:00
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80 and 85 degree electric retract units are available.

Bob Cotsford22/01/2020 12:13:54
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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.

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