[PSUBS-MAILIST] Pneumatic Rotary Actuators

[Alan James]

Thanks Jim K & T,
thats got me re-thinking things. I might be better to rotate via an electric
motor inside the hull & hold with pneumatics outside. I've got an idea those
rotary actuators are expensive.
Alan 


________________________________
 From: "JimToddPsub at aol.com" <JimToddPsub at aol.com>
To: personal_submersibles at psubs.org 
Sent: Sunday, April 6, 2014 2:43 AM
Subject: Re: [PSUBS-MAILIST] Pneumatic Rotary Actuators
 


Hi Alan,
Could you use a sealed-unit worm gear operated by a small 
electric motor?  That would hold at 180 degrees or any 
other position you desire.
Jim
 
In a message dated 4/5/2014 8:13:43 A.M. Central Daylight Time, 
kocpnt at tds.net writes:
Hi Alan, 
>
>
>If you use a thru hull, a linear actuator working at 12, 24 or 36 volts  works well as well as giving more positive locations than air. They are simple  and robust however slower than an air cylinder.
>
>
>You can find some examples at www.surpluscenter.com
>
>
>Best Regards,
>
>
>
>
>Jim K
>
>
>
>On Fri, Apr 4, 2014 at 5:10 PM, hank pronk <hanker_20032000 at yahoo.ca> wrote:
>
>Alan, 
>>you  can rotate 180 degrees with a single air cylinder and a watts  link.
>>No  need for an actuator
>>Hank
>>On Friday, April 4, 2014 4:04:18 PM, Alan  James <alanlindsayjames at yahoo.com>  wrote:
>>
>>Hi, 
>>I'm wondering if anyone has had any experience with either  pneumatic
>>rack & pinion actuators, or rotary vane actuators, operating  underwater.
>>I need to rotate something through 180 degrees & have it held with  a bit
>>of clamping pressure at one end of  the motion.
>>One concern is seawater getting in to the gearing of  those items, & there reliability. 
>>Another option, could be a normal pneumatic cylinder  with an external
>>rack & pinion added. Am trying not to have to go  to hydraulics.
>>Alan
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>
>
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