Tilt Mechanism

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Tilt Mechanism

Postby martin007 » 10 Aug 2022, 23:34

Hello!

I use a basic electric powerchair.
However, there are people who need to bow the position of the chair and body.
The reasons are several.


The reason for this problem is to investigate the different inclination mechanisms in the market.

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Pros and cons.
Opinions and experiences about it.
Use together with R-Net.
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Re: Tilt Mechanism

Postby Arima » 10 Aug 2022, 23:49

This is a good topic. I'm interested to know more about connecting and powering these things. Can you take a clear photo of the connectors. How many pins do they have? A bright light will help make a good picture. Maybe you can touch some hot wires to the pins and see what happens:) Do they have a sticker that tells the voltage needed?
Thxs
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Re: Tilt Mechanism

Postby slomobile » 11 Aug 2022, 04:43

Maybe it is different in other countries. In the US, a basic chair is a group 2. They do not have tilt, or lift as a bureaucratic rule. A group 3 or 4 is a rehab chair and may have tilt, or not depending on who it was ordered for with what injury. If your model of chair is available with tilt, but your unit does not, you're usually best off using the actuator from the sister model that comes with actuator. Sometimes there are several different actuators for a given model. They may look very different from each other because they use a different motor/gear arrangement but be completely interchangeable. Or, 2 actuators may look identical and not be interchangeable.

The important things are
style of mount points (clevis, bolt, pin, ball and socket, etc),
clears obstructions on chair,
Stroke length,
closed length (or open length is specified sometimes instead),
force minimum,
and having the feedback type your particular controller expects (internal limit switches broken out to connector, limit switches in series with 2 motor leads, external limit switches, softpot, external pot, absolute encoder, incremental encoder and home switch, programmable actuator).
You may be able to change programming to expect a different type of feedback, but I wouldn't count on that.
If you are adding a tilt actuator to a basic chair that never had one available, use a 2 wire internal series limit switch actuator and a DPDT momentary toggle switch to reverse polarity.

Less important are connector type, speed, style of actuator drive, brand, voltage.
A fast actuator is more easily backdriven by leaning on it. If you are heavy, get a slow actuator.
They are almost always 24v actuators because that is what the chairs have on them. 12v actuators will live for a little while behind 24v. 24v actuators will work indefinitely at 12v, but will have half the rated force and speed.
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Re: Tilt Mechanism

Postby shirley_hkg » 11 Aug 2022, 06:19

Actuator with limit switches is easy to work with, as you don't have to worry lock-up at ends of travel . 6000N one is around £40.
Tilt seat can be as simple as 2 pivot points and a actuator via a toggle switch ; for power base wheelchair.

It's difficult and no good result on a foldable wheelchair with sling seat . . otherwise .


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Re: Tilt Mechanism

Postby Burgerman » 11 Aug 2022, 10:12

With PG systems inc R-Net you dont have to worry about stopping at end of travel. So you only need 2 wires straight to the motor. Just connect them to the two correct connectors on the ISM6 or whatever module you have. Then set it to auto detect endpoint. It watches for the point where the current begins to rise as the motor starts to stall, and chops of power in a couple of ms. No other complication required.

UNLESS as a position microswitch. As used on tilt on many chairs. sometimes backrests. This then connects to an inhibit channel so that you can program it to go slow when tilted.
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Re: Tilt Mechanism

Postby Burgerman » 11 Aug 2022, 10:23

AND...
A 12v actuator works fine, you just set the speed to 50% as shown in yellow and then it gets 12V instead of 24...
And you dont need end point microswitches etc. Just simple 2 wires connected directly to the actuator motor. Note ENDSTOP DETECTION can be set to disable or enable for each actuator. It works super fast and doesent overload actuators.

Also you can set current maximum allowed. This should be measured with a clamp meter you in the chair and set to around 2A higher than you need for up and down independently - use a clamp DC ammeter. Then no way to burn out anything in use.

See here:
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Re: Tilt Mechanism

Postby TetraIytic » 11 Aug 2022, 13:50

If you are messing about with actuators it's worth considering speed. Two identical looking actuators from the same manufacturer probably have identical motors and achieve the lifting force differences by varying the mechanical advantage in the mechanism. This is done by helix angle or gearing.
WCS agreed to fit a lower seat mechanism on my chair so I can get in the car without hitting my head on the headlining. When the chair was returned the tilt run slower than half speed, about a minute end to end. After convincing them that was a problem, they sent a techie out from the manufacturer who put a meter on the charging socket and declared it was giving 24 volts, it must be in the software. I already knew it wasn't. Originally I thought someone had selected 12 volts .
After A bit of detective work I had to explain 1.5 kN actuator should be fitted. They had fitted a 2.5 kN actuator which was on the shelf and was the same size when they had modified the chair,. The speed of OEM actuators is usually in the part number or product code . This often goes missing with rebranding.
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Re: Tilt Mechanism

Postby Arima » 12 Aug 2022, 01:41

Great information from everyone!
Thxs
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Re: Tilt Mechanism

Postby martin007 » 12 Aug 2022, 18:24

Arima wrote:This is a good topic. I'm interested to know more about connecting and powering these things. Can you take a clear photo of the connectors. How many pins do they have? A bright light will help make a good picture. Maybe you can touch some hot wires to the pins and see what happens:) Do they have a sticker that tells the voltage needed?



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0132.JPG


P.S. The photographs aren't mine.
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Re: Tilt Mechanism

Postby Burgerman » 12 Aug 2022, 22:31

Those are just the powerchair companies connectors in the loom.
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