WheelchairDriver

Hiya

Do you build for others?

Thanks

No sorry.

There are others here building custom chairs, similar, totally different and everything in between.

That's a shame as I am really struggling to find something I like and am in my wheelchair all day, so it's kind of important . If there is anyone who reads this who would be prepared to talk to me about building something please PM me. I don't have the physical ability to build myself. I'm primarily looking for range, responsiveness and reliability over speed. Oh and comfort lol.

Where are you located?

Cambridge but can travel

John...fellas,i need a tilt actuator to make a elec.footrest....the one at pics from " evilMO" cant even lift "mis cojones" it has 300Nm...
please,post me ebay links or similar,so i can buy,obg


https://onedrive.live.com/?cid=7b7bd86f ... RzLu-U3ZCA

https://www.servocity.com/index.html

There are actuators here that will lift several cars...

https://www.servocity.com/html/12v_line ... ators.html

which one should i choose from servocity ?

and from this link which is the right one ? http://www.ebay.co.uk/sch/i.html?_odkw= ... k&_sacat=0

You need to know:

Linak bad reputation...

Voltage
Stroke length.
Shortest length rom mounting to mounting.
Newton's or pounds force required minimum
Acceptable speed.

10 newton is 1 kg or 2.2lb. Ish...

Actually its the force needed to accelerate 1kg at 9.8 metres per second per second but this is close enough.

As long as its small enough, fast enough, 12v or 24v, and has enough power (how much you need?) x2 then it will be fine!

http://www.ebay.co.uk/sch/i.html?_from= ... =&_sacat=0

http://www.ebay.co.uk/sch/i.html?_odkw= ... =&_sacat=0

the seat tilt actuator + footrest actuator,work with 12 or 24V ? OBG

As long as its small enough, fast enough, 12v or 24v, and has enough power (how much you need?) x2
John, x 2....?

Yes, if you need it to be able to push with 40kg, get one that can do 80...

12 or 24V ?

Your choice.

Depends how you power it.

Your R-Net is set up for 12v actuators - Linak actuators are OK and easy to find cheaply. If they make a grinding sound replace them.

LC

You can get servo ones. (they go to a position based on a pulsewidth). And they can be driven directly via a model heli gyro. So you could choose an angle via a knob (a cheap servo tester), and as you go up and down slopes or ramps the seat will stay in the same position and ignore the chair. If you get a fast ram/actuator.

Burgerman wrote:You can get servo ones. (they go to a position based on a pulsewidth). And they can be driven directly via a model heli gyro. So you could choose an angle via a knob (a cheap servo tester), and as you go up and down slopes or ramps the seat will stay in the same position and ignore the chair. If you get a fast ram/actuator.

r

John...put that in 'pics for me to " compreender" better. obg (isn t linak a servo ? i use linak for 17yrs = no problema... )

L.C,Can P&G Actuators sockets be adjust to 24V via OEM ? Obg

John.
Do Sunrise dealers drop there motor prices from time to time or have a sale on
As they are cheaper at minute or is a new model out.?

Most dealers get 30% off. And you don't pay VAT. So if you are good at dealing you can get some discount...

But no offers on parts.

My experience with Linak is that they are CRAP!! Poor build, and bad engineering. Among other things they use PLASTIC for load bearing parts, and do NOT have 'End-of-travel' limits, so they can easily be overdriven. (Supposedly, they depend on detecting excess current draw in the controller circuitry, but this isn't real reliable and can cause additional problems...)

I've gotten some actuators from Progressive Automation, and have been favorably impressed by them.

As BM mentioned you need to know

Voltage
Stroke length.
Shortest length from mounting to mounting.
Newton's or pounds force required minimum
Acceptable speed.
10 newton is 1 kg or 2.2lb. Ish...

Voltage can be anything, but 12 or 24VDC is usually best for chair use. If buying new, this often can be specified (but may cost a lot extra - Progressive does 12V stock, 24V is usually about $50 extra) If controlling the actuator with chair controller electronics (i.e. using the joystick) then you need to match what the controller puts out. OTOH, if using a toggle switch, then you can either use 24V directly, or go through a DC-DC (Pick one with an output current greater than the actuators maximum rating) to get the voltage needed for the actuator.

Stroke length is almost always going to be 2X the minimum length, plus some amount for the gearbox parts, and mounting bits - this should be in the data sheets. Since in many cases, the same gearbox and such can be used to make several different models with different stroke lengths by swapping out the driven shaft and tube, you will often see the lengths described as 'X plus stroke length"
i.e. 3" plus stroke would mean 9" minimum for a 6" stroke, or 39" minimum for a 36" stroke.

You also need to pay attention to the orientation of the mounting eyes with respect to the motors, and the motor mounting position, and make sure that you don't interfere with any other hardware. Some actuators can have their mounting eye orientation changed, others can't...

In general, you need to look at all the dimensions for clearance, and how you will mount the part, but the open / closed lengths are the critical ones.

For any given actuator size, there is a usually a trade-off between power and speed - more power = slower speed. Within some limits, you can get slower speed (and less force) by lowering the voltage, but it is risky to try to get more speed / force by increasing voltage, as you are looking at a motor that is working pretty hard at it's rated output.

Also as you'd expect, more force at a given speed will also mean a bigger motor and shaft diameter

In looking at the force, you need to consider both the 'dynamic' force, or how hard the motor can push / pull (note that this CAN be different for push and pull, but usually isn't) and the 'static' force, or how much the actuator can hold when there is no power on the motor - typically this will be higher than the static force, but not always.

In addition, you MUST consider the leverage and angles that the actuator will be working through, as the amount of force needed to lift the same weight will vary drastically with a change in the lever length - how to do this is more than I'd want to cover in a short post, but is critical to getting something that works.

I also like to insist at a minimum on having 'end-of-travel' switches at the travel limits, and if the actual travel allowed / desired on the device is less than the mechanical travel of the actuator then additionally adding switches at the desired travel stop points - this is especially critical if it isn't immediately obvious when at the end of travel, as it prevents burning out the actuator motor, as well as possible mechanical damage.

ex-Gooserider

Also if powering with a r-net look at max amps.

Nandol,
You can have 12 actuators with a 12A limit - the lights can be 12v or 24v - not sure about the actuators.

LC

Take a look here:

www.wheelchairdriver.com/pdf-files/r-net.pdf

Because 12A at 24V is twice as much power (better faster ram) 12A at 12V...

It is probably adjustable. No time to look gone to pub!

fellas,is this ok for my new chair http://www.ebay.com/itm/Invacare-Power- ... 4191994677

chair pics https://onedrive.live.com/?cid=7b7bd86f ... RzLu-U3ZCA

off to beach...why ? see here https://www.facebook.com/video.php?v=15 ... tps%3Av%3D

I need some of those freewheel levers... What are they and where from?

The actuator will be slow, and its not very pretty. But will work I think. Much depends on getting the linkages and angles correct. Your blacksmith friend will get it right!

If you want Ivanov can make those freewheel levers for you...How many do you want?
The actuator from link above costs $50 US + 50 for shipping....I think its a good deal, dont you?

Actuator is ugly. I would find something else. Price is OK but its messy!

I may be able to find something for levers. Will let you know.

I was able to buy a brand new actuator for Rachi's tilt made by an Italian manufacturer (MecVel) for about E100. I was able to chose exactly the speed and stroke I wanted, and it's also pretty decent looking and all metal. That ebay one is not enough saving for something that may, or may not, have the specs you need. Figure out what stroke, force and speed you need, do a search for linear actuator manufacturers (there are lots, you may even find one in Portugal, or at least dealers/distributors in Portugal) and start to look through their catalogs. Then contact their distributors or dealers to get prices.

Ciao,
Lenny

Burgerman wrote:Actuator is ugly. I would find something else. Price is OK but its messy!

I may be able to find something for levers. Will let you know.

that would be great John...but i need 2 actuators,one for each chair,obg

andithornton wrote:Cambridge but can travel

'Disambiguation needed..." There are LOTS of Cambridges - the one where Harvard and MIT are, which isn't far from me, and then there are a bunch of other ones, even over in England, or so I've heard....

Seriously, if you go to the 'User Control Panel" you will find a spot where you can enter your location, which will then show up under your username on posts. It is very helpful to put at least your country and general area, as that will get more helpful answers when location matters.

ex-Gooserider