Modied gear lever for a disabled motorcyclist 2

[azarl]

Hi
I'm designing a hand gear shift to replace a foot shift for a disabled motorcyclist, similar to this:

I have an issue with vibration though, as there is a lot of backlash in the gear shaft and the shift lever oscillates about two inches in each direction. The gentleman I am building this for has difficulty in catching the moving lever. I've tried using springs and/or dampers but that makes the lever too hard to shift. Has any one an idea on how I can keep the lever from moving without making it too hard for the rider to change gear?

Thanks you

 

[MacGyverS2000]

There's already a handle to squeeze for shifting, so have that same handle (separate cable) operate a friction-hold clamp to keep it from moving once released.

Dan - Owner

http://www.Hi-TecDesigns.com

 

[3DDave]

It would help to see your installation, preferably more than one photo.

Other than that, reducing clearance is of great importance and increasing stiffness near any joints is important. Reducing mass far away from the pivots/joints also helps.

For example, if parts are carefully reamed to size instead of drilled very small clearances can be achieved. Making the pivots longer allows thicker parts, which increase leverage and increase stiffness. And using steel for high stiffness near pivots, but bolting on aluminum levers. For example - the item shown could lose almost half the vibrating weight by replacing the part of the shifter above the bend with a similar thickness of aluminum. This would significantly reduce the torque from vibration at the pivot.

If you look at the taper in the thickness of a leaf spring stack you can see the progression of material to resist the force applied.

 

[LittleInch]

I agree needs a bit more definition, but one thing is that if, as you seem to be, you are trying to replicate the movement an able bodied rider would do is to copy that as much as possible. In this instance it means not actually attaching the rod to the actual gear shift lever, but creating an implement which allows the gear shift lever to move with some space between the hand shift device. If you cant guide and dampen the lever then you're going to get movement.

You don't ride along with your foot resting right on the gear change lever at all times but just make contact up and down when you need to. Try and copy that.

Couldn't you make an electric solenoid type actuator which works off a push button or buttons?

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[SwinnyGG]

Couldn't you make an electric solenoid type actuator which works off a push button or buttons?

You could buy one- depending on the motorcycle in question. If it's a sportbike there is is most likely an off-the-shelf kit.. they're not all that expensive.

TransLogic is my personal favorite (I'm not affiliated, just used their product a few times) but there are many companies building these kits.

http://www.translogicusa.com/powershifters.php

 

[EdStainless]

Look at how it was done in the 1930's. They used a guide for the shift leaver. That way the linkage could vibrate but the shift knob would be in a constant location.

= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, Plymouth Tube

 

[djhurayt]

How about a push-button air shifter?

you might want to have this post moved to the Motorcycle Engineering forum, may get more exposure

 

[DAVIDSTECKER]

https://www.mcmaster.com/#ball-detents/=1bwepu6

Have you looked at a ball detent assembly?

 

[azarl]

Thanks guys, The picture was just an example, not one I actually made. Some ideas for thought here, thanks.

I've already tried out a solenoid shifter but the rider has difficulties operating the clutch and pressing the correct button simultaneously.

 

[LittleInch]

It's not easy replicating this and it strikes me that the example pictured needs the rider to ride one handed when changing gear?

Is there anything else the rider can do while riffing worth both hands and squeezing the clutch lever? Squeeze a button with his or her knee? Blow or suck on a tube in the helmet? Pre choosing up or down and then using the clutch lever to do both actions?

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[BrianPetersen]

For certain modern bikes, you can get quick-shifters (for upshifts) and throttle-blippers (for downshifts) that allow gearchanging up and down without using the clutch. You can even upshift and downshift without the clutch on a normal bike if you have a good feel for the controls.

There is an automatic (centrifugal) clutch which is available for dirt bikes but the name of it escapes me right now.

For drag racing applications there is what they call a "slider" clutch which is basically centrifugal engagement. (Don't use a "lockup" - that's not the kind you want.) The slider clutches will ordinarily be calibrated to engage at high engine RPM and aren't designed for street use, but perhaps something could be adapted.

 

[SwinnyGG]

I've already tried out a solenoid shifter but the rider has difficulties operating the clutch and pressing the correct button simultaneously.

Did you put shifter controls on the same side as the clutch handle? They should be on the throttle side.

 

[azarl]

Thanks again. The cabled friction mount did the trick. I'll post a picture when it's all finished

 

[BrianPetersen]

The name of the automatic clutch came to me: Rekluse.

https://rekluse.com/

https://rekluse.com/faq/

If the rider has to hand shift, this would free up the clutch hand to be able to do so.

 

[azarl]

Thanks Brian