Hello everyone, this is my first post here and I am new to the T world. I bought myself what I believe is a '25 TT ton truck. I am currently learning and familiarizing myself with all of the parts, and I do not know what this is. It's attached to my driveshaft with a U-bolt, and isn't attached to anything. It has rocky mountain brakes at one point so my guess is that it was hooked up to the brake rods as an equalizer? Please let me know if i'm right or wrong, thanks!
[IMG]http://i143.photobucket.com/albums/r143/ledeeed/2012-11-05124408.jpg[/IMG]
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I don't know what it is, but whatever it is, it's not a stock TT item. I'm curious to see what others have to say about it.
Here it is after I took it off of the drive shaft.
Sean-
It looks like an equalizer for outside brakes.
: ^ )
Keith
+1 what Keith says.
If anyone can find any pictures or information about this part, please let me know. I might just have to sell it as "Brake equalizer???"
No I think you will have to sell it as "Way cool brake equalizer!"
I'm interested! I'd like to have it.
Open to offers, I am planning on cleaning it up a bit. The threads are kind of rusty and a little beat up so they need to be re-threaded, I may try to get that done as well.
I think it was intended for pull-brakes, but it is not an equalizer. It is, in fact, an anti-equalizer, ensuring that both sides receive exactly the same pull. If one side stops first, then no further force is given to the other side. An equalizer pulls a single bar from the middle and distributes the force through the span of the bar. If one side stops moving first, then it acts as a pivot, and the other side is given force freely. Note that the assembly is purposefully made so that the center cannot act as a pivot.
"Rocky Mountain" (AC) brakes are an example of a true equalizer.
An advantage to this odd setup is that if the rod on one side breaks loose, the other side still tries to stop the truck. With an equalizer, if you lose one side then you've lost it all.
Jim
Jim,
If you look closely at the device you will see that the center pull member is free to move sideways a little bit. This freedom to move sideways and the little links that connect it to the main levers will in fact act as an equalizer. If one brake tightens before the other the center member will move to the side and put more force on the side that is still slack.
An ingenious little device.
Jim
If the center is pulled on the underside, then this would in fact provide a pushing action to the wheels. I think it is more likely that a pushing action from the pedal provides a pull at the wheel...Thanks, John M.
could be a Turning Brake and the levers for the cab are missing?
No, it would pull at the wheels. If the two short members, which form the "V", were to be pulled at their connection point to the center member, they would flatten out the "V", thereby pushing the shorter arms of the two "L" members apart and swinging the long arms of the "L" pieces forward, toward the engine.
John,
Based on the way that it is mounted in the linked photo, then pulling forward on the center part would also pull the ends away from the rear brakes.
Jim
Here's a picture of the underside:
It's also a pressure multiplier
Jim Thode,
I must disagree that there is any equalization in this device. There is only one force-vector component on one pivot point that applies force to the two arms. It's specifically designed so. Also note the rivet in the center of the arm, between the bolts. It apparently rides in a groove in the casting, trying to keep the arm centered. This arm is permanently biased to one side, so that the single pull-rod is dedicated to the left side.
It is definitely a force multiplier, by about 1.41.
Jim
James - Not to start an argument here, but in reading carefully what Jim Thode said and thinking about it, I think he is absolutely right. Certainly the way this device is designed and built, I'm sure that there is some "play", "slop", "lost motion", whatever you want to call it, that would allow it to function as an equalizer. Just the rivet in the center of the arm that you mentioned, riding in a groove in the casting, trying to keep the arm centered, will certainly slide loosely enough to allow those long arms to work with enough flexibility to act as an equalizer. I do think however, that the main function of the whole device is to act as a "force multiplier" as you call it, and provide enough mechanical advantage to considerably lessen the force needed to be applied to the brake pedal,....sort of a "mechanical power brake" effect. Interesting for sure,.....harold
I think the rivet head is just to keep the actuating piece from moving too far back. Of you look at the photo of the under side there is no slot or rivet showing.
Here are a couple of photos. One with the normal operation and a second showing it working as an equalizer with the right side fixed and the left side free to move.
Jim
This is amazing!
Harold,
By Jove, Sir, you are correct, as is the other Jim!
An equalizer works by being able to change the position of the pivot point. In a simple equalizer brake, one side always stops moving first, if only by an extremely small margin. At this point in the braking, the immovable rod instantly becomes the pivot for the equalizer bar, which is now a lever exerting force on the still movable brake rod until both become immovable.
In this special arrangement, one side lever will always stop first. At that point, the interior pivot for that lever becomes a fixed pivot for the other side, and the main bar continues to apply force to the other side, moving slightly to the side as the sub-levers work.
This had the advantages of both an equalized brake and an unequalized brake. The force will continue even though one side has grounded out, and yet a failed rod on one side will still allow braking on the other side.
Pardon my mistake, and thank you for questioning my analysis.
Sincerely,
Jim
Must not have been very popular if no one has seen one before. The more parts involved, the greater the chance of failure. KB