Model Boat Mayhem

Please login or register.

Login with username, password and session length.
Pages: [1]   Go Down

Author Topic: Linear Servo  (Read 2320 times)

pipster

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 148
Linear Servo
« on: August 18, 2018, 07:43:24 pm »

Hi,
I'm after a linear servo with a throw of 20mm and torque of 3.0 kg-cm.  Does anyone have any suggestions of where I could get one?


Cheers
Phil
Logged

derekwarner

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 9,463
  • Location: Wollongong Australia
Re: Linear Servo
« Reply #1 on: August 18, 2018, 10:12:31 pm »

Phil.....3kg & 20 stroke appear just outside the run of the mill available in Kellogg's Corn Flakes type linear servos

Try Servo City in America.........they appear to have an extensive range of linear servos............. ]......Derek

https://www.google.com.au/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&cad=rja&uact=8&ved=2ahUKEwiCntvJwffcAhUHQd4KHQn5DPkQFjAAegQIAxAC&url=https%3A%2F%2Fwww.servocity.com%2F&usg=AOvVaw0qgfkocPrk02xtt4Tn5gQF
Logged
Derek Warner

Honorary Secretary [Retired]
Illawarra Live Steamers Co-op
Australia
www.ils.org.au

pipster

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 148
Re: Linear Servo
« Reply #2 on: August 19, 2018, 03:57:45 pm »

Thanks for the tip Derek,


I've had a look and it looks like they only have linear actuators as opposed to linear servos.  I'm tight on space so I think a linear servo is the only solution.  I could probably get away with a little less torque if that opens up some more options?


Phil
Logged

Subculture

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 4,187
  • Location: North London
    • Dive-in to Model submarines
Re: Linear Servo
« Reply #3 on: August 19, 2018, 09:35:24 pm »

Logged

Andyn

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 994
  • Location: Northamptonshire
Re: Linear Servo
« Reply #4 on: August 20, 2018, 01:35:31 am »

How limited on space are you? Savox do micro servos with more than that amount of torque...


https://www.servoshop.co.uk/index.php?pid=SH0256&area=Servo - See specs - 4.6kg at 6v.
Logged

Subculture

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 4,187
  • Location: North London
    • Dive-in to Model submarines
Re: Linear Servo
« Reply #5 on: August 20, 2018, 08:43:14 am »

Are they linear motion? Afaik the only company producing new linear servos above micro size, was Becker in Germany. A heck of a price too.

The only other alternatives would be to scout about for old servos e.g. skyleader used to make linear servos. Not sure their servo amplifiers would work with modern radio though.
Logged

richald

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 1,941
  • Retired and loving it!
  • Location: Driffield, East Yorks.
Logged
Senior member of the OGG (Order of the Grumpy Gits)
Membership Number : 002

pipster

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 148
Re: Linear Servo
« Reply #8 on: August 22, 2018, 02:08:55 pm »

Thanks all for your suggestions. 
I've tried a mini/micro servo, which is where I've got the torque figure from.  The issue is that it's to lift a mast via a Bowden cable (if that's the right term as its a twisted wire) and the cable is tending to kink rather than lift.  I think the circular motion of the servo is contributing to that.  So my idea was to shorten the length of unsupported Bowden cable and use a linear servo.
I may give a micro linear servo a go, just to see one is torquey enough and also try the micro servo with a shortened cable. 

The EMS servo converter looks like an option too - I'll have to contact them about payment though as I don't have a credit card!!

The firgelli pq12 rc looks like an interesting option but not cheap!!
Phil
Logged

barriew

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 2,111
  • Location: Thaxted, Essex
Re: Linear Servo
« Reply #9 on: August 22, 2018, 06:33:11 pm »

Pipster,


I used standard servo to operate the drop down loading ramp on my Calmac Ferry. I found that the cable had to be supported over as much of its length as possible.


Barrie
Logged

malcolmfrary

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 6,027
  • Location: Blackpool, Lancs, UK
Re: Linear Servo
« Reply #10 on: August 23, 2018, 09:02:47 am »

Twisted wire is great for pulling, useless at pushing, especially if a change of direction is involved.  Most things that use twisted wire have a return spring to work properly, think of bike brakes and gear changers. 
A servo raising a mast might need something to slow it down to avoid it looking like a trebuchet arm.
Logged
"With the right tool, you can break anything" - Garfield

barriew

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 2,111
  • Location: Thaxted, Essex
Re: Linear Servo
« Reply #11 on: August 23, 2018, 10:44:51 am »

True Malcolm, although my ramp does work.  :-))  The other alternative is a 'snake' as used by the model aero guys, although I found that still tended to flex. I used an Arduino to slow the motion and limit the throw.


Barrie
Logged
Pages: [1]   Go Up
 

Page created in 0.088 seconds with 22 queries.