adjusting handlebar stem height quickly on a bike

[JohnDeere8530]

As per previous post I have made a wheelchair into a trike for a disabled chappy.
The thing is he needs to occasionally adjust the stem height of his handlebars quickly when about to make a sharp turn in a confined space. This will enable the handle bar ends come over the top of his knees when turning. Once he has turned they can be dropped again.

It is a standard 22.2mm wedge type stem with a long centre bolt. Has anyone ever seen this with a quick release lever on the top (such as you might get for attaching bike wheels)? Ideally there will be a stem manufactured for this, but I cant seem to find one even with the aid of google.

I would be grateful for any advice

 

[onmebike]

I've never seen a quick release handlebar stem before but couldn't you make one yourself using threaded studding to replace the central bolt and a wheel quick release mechanism?
Or you may be able to convert to one of these, KF ZOOM Quick Release Adjustable Quill Stem :: £39.99 :: COMPONENTS :: Handlebar Stems :: CYCLEWORLD

 

[flecc]

The Gazelle Easy-Glider (photo below) had a lever operated quick-adjust extension doing the same thing. I don't know the type and size but maybe a Gazelle dealer can advise:

 

[Old Timer]

As per previous post I have made a wheelchair into a trike for a disabled chappy.
The thing is he needs to occasionally adjust the stem height of his handlebars quickly when about to make a sharp turn in a confined space. This will enable the handle bar ends come over the top of his knees when turning. Once he has turned they can be dropped again.

It is a standard 22.2mm wedge type stem with a long centre bolt. Has anyone ever seen this with a quick release lever on the top (such as you might get for attaching bike wheels)? Ideally there will be a stem manufactured for this, but I cant seem to find one even with the aid of google.

I would be grateful for any advice

My wife has a Synergie Breeze that came with an adjustable quill type stem, Alien took over synergie gear and I`m not sure if they have any bikes left but if you speak to Jim he might have some odds and sods.

Having said that, I`m not sure how long the mech would last if it was released and relocked on a regular basis.
I think I`ve seen quick release handlebars that would allow you to swivel the bars up and down to give you the clearance but of course if you want to do that from a sitting position it might be a bit of a reach.