Internal Door Handle mechanism question..

[daicos35]

Hello all,

see pic attached of internal handle mechanism on doors.

One seems to have a "lead wedge" with a felt protection strip on it, one does not.

I know nothing about the function of this part, and cannot find a clear part number on the bmw etk system.

Am 100% sure it is NLA , but would like to source one with the "lead wedge", if someone can confirm the purpose of such wedge!!

My brain cannot handle having one side not matching the other, will clearly lead to significant performance degradation of some kind.

Cheers,

Mike

 

[HB Chris]

I think it is meant to keep the handle from rattling.

 

[daicos35]

mmm, yep, makes sense.. so I need a mechanism... anyone know if this was a shared part with the e3?

 

[Cornishman]

Just ignore it and reassemble the car, they work fine without this lead weight.
One of mine fell off about ten years ago.

 

[HB Chris]

One of mine fell off too and I didn’t reattach it.

 

[Arde]

I think the lead bar is a counterweight. I have it on the E24 and E9.
The purpose is similar to counterweights in garage doors and elevators, which is to balance forces so that the external force needed is reduced and evened out.

When you open the latch you are applying a force that is opposed by a spring, the force of that spring is proportional to the angle of displacement, which means that it would start easy and become harder to complete the motion. We prefer operations that provide initial resistance (so the start is deliberate), but then get smoother to complete, just like when shifting gears.

By having the counterweight sitting vertical, it does not oppose the spring when the latch is closed. As we start to open the latch the counterweight tilts, gravity provides a force that opposes the spring that is proportional to the displacement angle, just like the spring. I do not think the forces just cancel because the spring force is linear vs compression, and gravity would be a trigonometric (sine) function of the angle. So it may be designed to get easier after start.

If you don't install it and the spring is strong, you would need to apply a stronger handle force to open the door, and thus break the handle earlier.

For me it was an open and shut case...

 

[HB Chris]

I thought it was to keep the exterior handle from rattling but I have no clue.

 

[Arde]

I thought it was to keep the exterior handle from rattling but I have no clue.

You may be right. I am surprised there is no documentation on the purpose.

 

[TomHom]

I came across the same question, I will forward it to our German forum.
Thomas

 

[Arde]

Great, the Germans may know the reasons. My theory is probably wrong because it seems like the E24 weight stays vertical. Looks like the E9 weight is also vertical and above the handle. That leaves the rattle theory from Chris as the only one at play...

 

[deQuincey]

mmm, yep, makes sense.. so I need a mechanism... anyone know if this was a shared part with the e3?

I think I do have a spare lead

 

[deQuincey]

about the

 

[deQuincey]

I think the lead bar is a counterweight. I have it on the E24 and E9.
The purpose is similar to counterweights in garage doors and elevators, which is to balance forces so that the external force needed is reduced and evened out.

When you open the latch you are applying a force that is opposed by a spring, the force of that spring is proportional to the angle of displacement, which means that it would start easy and become harder to complete the motion. We prefer operations that provide initial resistance (so the start is deliberate), but then get smoother to complete, just like when shifting gears.

By having the counterweight sitting vertical, it does not oppose the spring when the latch is closed. As we start to open the latch the counterweight tilts, gravity provides a force that opposes the spring that is proportional to the displacement angle, just like the spring. I do not think the forces just cancel because the spring force is linear vs compression, and gravity would be a trigonometric (sine) function of the angle. So it may be designed to get easier after start.

If you don't install it and the spring is strong, you would need to apply a stronger handle force to open the door, and thus break the handle earlier.

For me it was an open and shut case...

difficult to be counterweight being on the fixed part of the mechanism
but you deserved it for the elaborate engineering analysis
my thinking is that it increases the door panel mass by adding the lead
also look at the felt to avoid sratch8ng the glass

 

[Arde]

difficult to be counterweight being on the fixed part of the mechanism
but you deserved it for the elaborate engineering analysis
my thinking is that it increases the door panel mass by adding the lead
also look at the felt to avoid sratch8ng the glass

Yes, after I assembled it I realized it has to stay fixed. It increases the handle apparatus mass...
I did not remove my analysis as a reminder that talk is cheap, and that one should be skeptical whether it is a medical doctor, or a technocrat speaking, let alone an economist .

 

[daicos35]

If it presses against the glass, is it stopping the glass from rattling?

I do love this forum!!

I will look into how I can re create the lead wedge (unless anyone has on lying around?).

Cheers,

Mike

 

[sfdon]

Known as a “Balance Weight” by BMW.

It gives the door handle action a solid “feel”
optional to install. Many models have them. Here is the e23 …

​

 

[Arde]

It does not touch the glass. I like the "solid feel" description.
A weight must be the same reason I like heavy goose feather duvets even if it is not cold...

 

[deQuincey]

If it presses against the glass, is it stopping the glass from rattling?

I do love this forum!!

I will look into how I can re create the lead wedge (unless anyone has on lying around?).

Cheers,

Mike

I think I do have a spare lead

 

[deQuincey]

It does not touch the glass. I like the "solid feel" description.
A weight must be the same reason I like heavy goose feather duvets even if it is not cold...

also known as the duck in the pot, or the goose in the oven, better to have it there than to have not