DIY - Actuator feasibilty

Hi All,

Do some of you folks have idea on how I can increase (double or triple) actuator travel range by using some external mecanics design ?
Thanks.
OscarH

Hi Oscar cant speak for the other guys, but during my wanderings around the net most ideas seem shy away from leavers etc i belive ( and dont quote me on this ) its as much to do with moments of force etc, my interpretation was if i double / quadruple the throw by using a lever i would get improved travel range but the motor / actuator would also see x times the force applied backwards ie the weight of the moving part now exerts X times more force on the actuator so you end up beefing up the motor end and that useally means gearing down and a loss of speed or the need for a wormwheel gearbox arrangment which put you back where you started sorta :tape: ok i'll keep my mouth shut LOL:-0 in our game it always seems a trade off Spped vs Power(Torque) which i belive is why the SCN units are king of the hill at the moment for Freex type sims the heavier sims and platforms where all up weight can be anything above 200+ kg all seem to drift toward heavy duty wormwheel gearbox reduction units or high end ( big price tag linear actuators ( but hey there are some clever people out there and it will be sorted just keep watching da web :lol:

Hi Wannabeaflyer (nice name by the way ! :clap: )

In my simulator, the maximum force to move picth and bank is never above 15-20 kg, because the seat is positionned close to center of gravity of my body (so easy to move). But travel is appox 60cm for bank and 40cm for pitch. So, I don't think the force is an issue. Travel is one, and speed is another one.

I have an idea on top of my mind. Leave me some time to built then I will share...

Bye for now, time to go to work.
OscarH

Hi,
This is the actuator I got from surplus. First pictures was like I received it.
Devincox tried to get the 40 degree helical gear out, here it is. No so complex once you found out to proceed.
I think it can be replaced by a pulley separately, or a pully can be tighten on the helical gear itself.
Cheers.
OscarH

@OscarH,
Excellent! I must ask how you got that apart. I am having a problem getting mine apart and don't want to break it.

I circled the part in red, that I am having problems with.
I removed the wire and pin and assumed it was a threaded part but can't get it to turn or come loose. How did you remove that part?

I was thinking of making a pulley on my lathe/cnc mill. I thought a cogged belt would work. I found some cheap belts:
http://www.smallparts.com/Timing-Si..._s=center-3&pf_rd_m=AIUBT5HP6PMAF&pf_rd_t=301

and could just make a pulley to match, like the one at the following link:
http://www.smallparts.com/Filled-Si..._s=center-3&pf_rd_m=AIUBT5HP6PMAF&pf_rd_t=301

What do you think? If it works, I can make you a set as well.

Many thanks,
Devin

Hi,
Been caught at the same level until I found how to move forward...
Remove the wire and the pin, then simply unscrew like a nut. Unfortunately, this is not a hex nut, so you have nothing to hold it properly :-(
I used my bench wise to hold it on one side, while using a gripper (?) on the other end.
See detailled picture, so just unscrew...
Hope this help.

About pulley, let me investigate. I also have idea in using an old rear gear used on my mountain bike.
OscarH

Perfect. thank you for the picture. I will get to work on a pulley this weekend.

Regards,
Devin

@OscarH,
did you use a press to get the 40 deg. helical gear off? Mine will not budge. I am sick right now so I may be missing something simple. I've been wanting to get a small press, this may be the impetus for such a purchase. (c:

Devin

Hi Devincox.
I put it on the top of my bench wise, used a piece of wood, and a hammer.
Side you need to bang hammer/wood on is the side I took close pictures last days in this post.
Be carefull as the 'tube' can fall on the floor and damage the assembly. There is also a small key /cotter pin on the 40 deg helical gear. Don't lose it if it needs to be re-used.
Cheers.
OscarH

tried that but didnt work. i guess i will add some more elbow grease

Hi Folks,

finally found some time to move forward. Remember this cheap actuator was not motorised.
I used a standard motor found at Conrad/Selectronic with a 1:11 gearbox.
I used an old rear gear from my mountain bike, and here it is : working !

There are some limitations I am still working on : limit switches and feedback potentiometer.
The limit switches are mandatory as, per design, the actuator lock when reaching the limits, thus motor could burnt
Need also a protection for fingers !

Cheers.
OscarH

Hi Oscar Just tried to place an order for 2 off these units just to play around with basically but seem to have problems with the surplus center Checkout ,,, i see from your picture that your driving your actuator using a small DC motor have to ask how do you find the performance even with that size motor ... reason im aking is that for my motion simulator i need some decent actuators preferably linear like these , i have loads of scooter motors so having seen your setup just wondered how it handled itself .. Has any one else bought these units and had them shipped to Europe ?? or had any hassle placing their orders ?? am thinking of mounting these Back to back with a Common Gear drive so that i can get more travell if that make sense.. :

Hi folks,

The motor I am using is a MFA RE-540/1. Loaded, it is supposed to rotate at 13360 r/mn, and driving a 2.85 amps under 12 V. Torque is 154 g.cm.
Then I had a 1:11 gear box, and the extra ratio using the rear wheel of my mountain bike give an extra 14:24 ratio. Total ratio is then 1:19, not including the screwjack ratio (22 turns give 15 cm translation, but don't know how to convert torque into linear power).

It take approx 2 seconds for the 15 cm, that's not much, but enough for the setup I currently have.

Remember in my simulator, the center of gravity of the seat+driver is very close to the center of pitch and bank axis, thus not requiring a huge power/torque to have the seat moved back and forth.

I am in the early phase, so I need to move the seat from my old setup to the new one (and need to modify the second actuator for the pitch axis).
More to come when time permit, as usual.

I had not issue in ordering to Surplus shop. Both attenuators had been shipped within a week, or so, from order. I just had to confirm shipping cost prior the order, and these shipping cost where almost double price than the actuators themselves (total including S&H was approx 60 $), and I didn't had the local taxes to pay (passed through by chance).

I'm interested to find out if you can connect 2 actuators back to back. May not be easy to use a common gear, but probably not impossible.
Cheers.

OscarH

Hi Oscar Cheers for the quick reply ... will have another go tonight at placing my order if all else fails will Fax it over .. Did not want to get canned as it were for shipping costs so was trying to work out how much to send them to the UK will try and e-mail them again as for the back to back arrangment it was a nutty proffesor type of moment and when the units get here i will model them in solidworks and see what what assembly wise .. for my sim i need more travel Thanks will keep you all posted :

I found seller of high pitch lead screws (with price) : http://roton.com/Mating_Components.aspx?family=7059785 (with this screw you need only 960 RPM to get 400mm/s ).

Hi Mamabo now that looks like a serious contender for DIY Actuators and The big Big Plus is the Price ( its Affordable even for experimental trails) Guys can i get some feedback as to which Spec i would need to achieve 400mm/sec ... i can see this stuff being used for even larger motion platforms even to load carrying ability of the Plastic leadscrew Nut seems to exceed anything were likely to need and cheap enough to replace if they do wear out quicker than we thought ...... Great Find mambo am sure a lot of guys will be interested in this :clap: : i have Electric scooter motors that would work a treat with these parts so its safe to say will have to get a sample and try to Knock up a Demo Unit at work.. Just looked at the specs and noticed that because the lead angle is so greater than 5° these might backdrive ? does any one know if this is the case or better still a way to stop the backdriving ?

The screw 7/16 in has static load 544 kg and operating load 118 kg, diameter of screw is about 12 mm and pitch 25 mmpr. 0,5 m long screw shout withstand 544 kg without any damage (i dont calculate torque). If you have this screw and you want lift 80 kg and you want acceleration 800 mm/s^2 (from 0 to 400 mm/s for 0,5 s ) you need about 1000 rpm and 6 Nm (but you need more if you have 10 Nm its OK )

from the their web page
Non Self-Locking
All Torqspline® series lead screws have lead angles greater than 25 - making them non self-locking. This means they can backdrive readily and many are used specifically for converting thrust to torque. Brakes or other holding devices will be needed with Torqspline® Lead Screws to sustain loads after they have been positioned unless the drive train itself provides enough holding torque. For applications demanding self-locking screws, refer to the Acme screw section.

So we can try DIY Frex FF whell