Making a dropweight almost "automatic"

[Irvin]

Originally Posted by enderx1x

That would be good to know. Do you mind doing one test where you lower very quickly, and one very slowly? ...

Would not mind at all but I don't have a drop weight.

Originally Posted by Ray_cn

...According to the "speed of pulling", if a crank pulling slowly enough then it is most like constant pull with constant tension. For example 60lbs is the correct tension, pulling slowly, when the header arrive at 58lbs, pulling more slowly to the end.

...

Accordint to this pic, when the crank locked, but the spring is still working(If the crank's princple is same as i painted, tension head locked, but not locked both side of the spring, and the spring is a "Compression Spring"). I think it is still pulling too. Crank is continually pulling by the spring, as the continually pulling by gravity in dropweight...

In order for a lockout to tension as a constant pull you have to pull again. A constant pull (electronic) pulls to a set tension and stops (as a lockout) then it automatically pulls again when the string stretches and the tension falls (unlike a lockout.) So if you want to use a lockout and get the same results you would have on a constant pull you have to manually pull again.

http://www.youtube.com/watch?v=3aYI5DXQxSA&feature=plcp

The spring on a lockout has nothing to do with the pulling action. The spring controls how much resistance (string tension) is required to engage the lockout. Once the tensioner lockout out the brake is holding tension on the string. If the brake slips the tension will fall no matter what you set the tension on the tensioner. If you would like I can make a video of just how the lockout works.

[Ray_cn]

No problem. I have no that too:P

Yes, pull again is a method. I saw that video many times to see what happend when it locked. My tension head not in hand now.

Another method is to pull slowly according to that paper and a stringer reply in my post. He wait about 10s for the elongation stop in dropweight. Then pull slowly about 10s before reach the tension is a metod too. For example 60lbs, spend 10s from 58lbs to 60lbs before it locked.

Look at this pic, I repost here. The 3point limit the length of the spring continually pulling. But it is a limit. Not mean spring didn't continually pulling. It pulling shorter than dropweight. Dropweight could stop at -90degree, the tension is 0. For the crank, spring stop at the pulling begaining.

The locker locked the head axle, not lock the spring. The lever stopper stop the spring pulling.

Look at that video 3:46-3:51, the lever leave the lever-stopper about 2-3mm. That mean the string, lever,spring is in tension balance. But when the string elongated, the spring will pull it continually according to the lever theory, but pull at a lower tension as the dropweight do. And will stop pulling when the lever reach the lever stopper. It is very short. But the indicator is still at the correct tension. Not like it shown clearly on dropweight.

If you can try please wait some time to see if the lever return back to the lever stopper. Using a softer string mabe show clearly and quickly. If it returned, then it mean that the spring continually pulling as the gravity pulling.

I look at that video it is about 2-3mm after repull, maybe equal to the distance between the lever and the lever stopper. So maybe waiting the string elongation stop is ok.

Originally Posted by Irvin

Would not mind at all but I don't have a drop weight.



In order for a lockout to tension as a constant pull you have to pull again. A constant pull (electronic) pulls to a set tension and stops (as a lockout) then it automatically pulls again when the string stretches and the tension falls (unlike a lockout.) So if you want to use a lockout and get the same results you would have on a constant pull you have to manually pull again.

http://www.youtube.com/watch?v=3aYI5DXQxSA&feature=plcp

The spring on a lockout has nothing to do with the pulling action. The spring controls how much resistance (string tension) is required to engage the lockout. Once the tensioner lockout out the brake is holding tension on the string. If the brake slips the tension will fall no matter what you set the tension on the tensioner. If you would like I can make a video of just how the lockout works.

[Ray_cn]

This is most like the crank tension head. The green parts are not locked. So when the string elongated for senconds, the spring will pull the lever to a angle "c" which limited by stopper. "c" is much smaller than 90 in dropweight. But maybe enough.

So crank has continually pulling too as in dropweight. But shorter.

[Irvin]

The problem with your scenario is in reality the green part ARE LOCKED.

EDIT: The spring provides no pulling action on the string as shown in your diagram.

[Ray_cn]

Could you please show me where the green part being locked? It's a problem no tension head in hand, have to wait 1week to get it

Just saw it is lifted by the string in that video, but didn't find where is the locker of the green part. The locker only lock the brake pads in the head.

[Irvin]

No problem but I am getting ready to go out for dinner will make a video later tonight.

[Ray_cn]

Thanks, just want to learn where its locked and whether the lever will return to the stopper after the string elongated for a while.

[Irvin]

Originally Posted by Ray_cn

Thanks, just want to learn where its locked and whether the lever will return to the stopper after the string elongated for a while.

Now I see what you mean. The spring arm will not go against the stopper and there is some tension on the string from the spring. If you raise the tension on the dial even after it is locked out the tension will go up. But if you let it sit the tension will fall. Many people assume that a constant pull tensioner will pull at a constant tension where the crank will not it will pull to a set value and then stop and the tension will fall. A drop weight will pull to a set tension then rise or fall ever so slightly depending where the bar is above or below horizontal. Electronic pull at a constant tension.