Question
Asked August 5 2017

Community Question

I need to find a material that will assist my bubble lifter servo lift
the weight of my B9's finished bubble. It probably weighs about 5 lbs
or more. Without a helper the HD servo I'm using now struggles to lift
it and is slow to start moving upwards because of the weight. Up till
now I've used a stiff spring as a servo helper but it was causing
problems due to the way I had it attached to the lifting fork that is
in turn attached to the servo and the neck pipe. The spring was attached
to the front of the fork and pulling up on just one side causing
binding of the neck pipe. I want to move it to the rear "handle" of
the fork and perhaps make the tension adjustable somehow (adding a
turnbuckle?). I also thought I'd like to use a different material
other than a metal spring. Maybe a bungee cord and make it adjustable.
The thing is, whatever I use I don't want the material to degrade over
time or creep out of adjustment due to stretching. Does anyone have
any ideas on what material I could use that would stand the abuse of
wright, movement and time? I'll attach a pic or two of my present
design (without any spring attached). Thanks!

User-inserted image

User-inserted image

User-inserted image

User-inserted image
August 7 2017
Dave,
I appreciate your drive to improve and your effort involved.
I think your idea of a linear actuator is a great plan.
Steve S
August 7 2017
Hi Steve, Hope all is well and you're doing better.

I agree it should be the best way to go. However I'm not interested in the regular Hrydo filled linear actuator. There are newer electric linear actuator now on the market that don't require replacing fluid and seals. I'm looking into them now to see if they will meet my needs. Sounds promising. I wouldn't have found them with the help of people like are on this forum.

www.thomsonlinear.com/website/com/eng/products/actuators/pc_series.php

User-inserted image
August 7 2017
Ah can't beat Precision Linear Actuators, good choice Dave, will be silent and smooth as butter.;)
August 8 2017
Here is one I got for a robot I am building. Dave Cochran uses them on Rafiki.


User-inserted image


User-inserted image

I put a 6 inch scale for reference.

Strong enough to lift the world (225 pounds)
August 8 2017
Thanks Andy for going through this trouble. However I'll need one with at least a 4"stroke and able to make that trip in one second or less. Electric is preferred and not hydraulic.