Author Topic: The brake for my seventeen footer. (Read 4673 times)

Dave B · « **Reply #33 on:** February 13, 2010, 10:29:01 AM »

First ask yourself what do I want the brake for then design it for the application. What percentage of the time will you have use for the brake ? Are you trying to limit the speed possibly with frequent use like a car brake or just needing to occasionally use it as a parking brake ?

A cable operated parking brake can be simple, effective and reliable. Without slip rings yes the cable will wind around the power cable, you have to tend to the power cable anyway, no difference.

No need to re-invent the wheel, how long have cars been using this system ? There is nothing better than to know you have control over your machine. Dave B.

fabricator · « **Reply #34 on:** February 13, 2010, 11:55:49 AM »

A cable will twist the same as the power cables do, at the same rate, they are all hanging from and attached to the same point, this brake is only intended as a parking brake, possibly an automated/manual activation system but a manual reset switch, anybody know what wind speed/RPM is red line for a seventeen footer?

Activation would be some rpm just short of red line = brake on.

dlenox · « **Reply #35 on:** February 13, 2010, 01:47:38 PM »

Dale,

A lot of it will probably depend on how well you have it balanced as well as how well the blade tips are tracking.

I don't like to see mine go faster than 250 rpm, however think that somewhere around 300-350 rpm would still be a reasonable 'max' speed for a 17'er

Dan Lenox

fabricator · « **Reply #36 on:** February 13, 2010, 02:57:52 PM »

Thanks Dan, that is in the neighborhood I was thinking in, right now I have a air cylinder hooked up to it, I kinda like the way it works, I'll post a picture tomorrow.

Darren73 · « **Reply #37 on:** February 14, 2010, 01:26:01 AM »

Fabricator,

The problem will be that the brake cable with twist around the power cable and the two of them will lock together, when you want to use the brake the cable won't be able to move. If you want to see what I mean, hang 2 lengths of rope / extension cord or similar from a point above you, hold 1 in each hand and turn around a few times.

Just an off the wall thought as a posible solution, would using the power cable work? Instead of securing it at the top, allow it some movement so that pulling on it allows the machine to run, releasing it stops the machine, movement only needs a few inches of movement and gets away from the tangling problem of cable and wire rope.

fabricator · « **Reply #38 on:** February 14, 2010, 02:28:22 PM »

Is there any way to post pics in a comment? This is really getting old.

willib · « **Reply #39 on:** February 14, 2010, 09:38:03 PM »

Yes there is , but ittl cost ya

First you make like you are going to post a new story.

add any file in your files , this will serve as your template , so copy it to a text file.

Back out of the new story post.

Then just insert the pic ,that you wanted to post in a comment, into your template.

copy this and insert this into your comment.

Told ya it will cost ya

fabricator · « **Reply #40 on:** February 15, 2010, 05:37:55 AM »

OMG! If any body wants to see what looks like with the air cylinder attached just check out my pictures, they will be the ones that have W/cylinder in the name.

fabricator · « **Reply #41 on:** February 15, 2010, 05:51:31 AM »

fabricator · « **Reply #42 on:** February 15, 2010, 05:52:07 AM »

Holy crap! it worked!

TomW · « **Reply #43 on:** February 15, 2010, 05:57:21 AM »

Only ones I saw that matched.

Nice work, BTW

Tom

dlenox · « **Reply #44 on:** February 15, 2010, 06:33:03 AM »

Dale,

I see that with your cylinder that it has to pull the lever in order to operate the brake.

Since the cylinder rod is open to the elements there is the possibility that gunk and stuff can build up on the rod, potentially not allowing it to function properly.

You may want to think about pushing the rod to engage the lever, reason being is that the rod is protected inside the cylinder casing. So any built up gunk will not affect it's operation as the rod stays clean inside the cylinder.

That is the way that I did my 12v linear actuator on my turbine.

Dan Lenox

fabricator · « **Reply #45 on:** February 15, 2010, 09:52:30 AM »

Thanks Tom, Dan, that has been bugging me, I am looking at what I need to do to switch it around right now.

REdiculous · « **Reply #46 on:** February 15, 2010, 11:05:06 AM »

OR...

Go to your files, right-click the one you want and copy the link. In your reply, use the standard html img tag to insert the image...

< img src="paste the link here" >

BigBreaker · « **Reply #47 on:** February 16, 2010, 06:17:59 AM »

Or you could put a boot (sleeve) over the rod?

Tension is much more robust than compression in your design. Pushing will cause the mechanism to deflect out of true if there is any slop in the bearings or misalignment, especially as the brake is fully engaged (stopped out) but the actuator has more travel. Pull, pull, pull.

fabricator · « **Reply #48 on:** February 16, 2010, 10:13:11 AM »

How does this look to ya Dan? I like it a lot better, I had to turn out an extension lug that is also is a stator lock nut, but this is way better.

http://www.fieldlines.com/images/scimages/7707/New_brake_mount_1

http://www.fieldlines.com/images/scimages/7707/New_brake_mount_2

dlenox · « **Reply #49 on:** February 17, 2010, 02:38:34 AM »

Dale,

Yea I like it a lot better.

On my Vortex (3 wheeled project) it uses Nitrogen cylinders for the doors and rear canopy (http://www.briery.com/vortex/) and the manufacturers suggested that the cylinders be mounted with the rod downward.

Evidently this helps with the seals and allows water and gunk to flow away from the cylinder.

BigBreaker does bring up a point though, with enough pressure the actuator arm will deflect and possibly bend. Of course even when pulling you can still bend the actuator

I do like the mounting though, why not put on a side stiffner onto the actuator arm to eliminate any chance of it bending?

Dan

dlenox · « **Reply #50 on:** February 17, 2010, 02:47:23 AM »

BTW: You haven't mentioned how you will be powering the cylinder, is it pneumatic, hydraulic or electric?

I assume pneumatic but did not see any return line, so assume that the springs have enough strength to return the cylinder to 'normal' once the air pressure is turned off.

Next step: what are your thought for engaging the cylinder? using some governer or something? I also assume that manual control is always an option as well. Plus you having an air cylinder or air line? What to do with yaw rotation?

You have some very good first steps here, the devil will be in the details...

Dan Lenox

fabricator · « **Reply #51 on:** February 17, 2010, 03:59:27 PM »

It's an air cylinder, my intent is to run an air line to the alternator, it will be stainless tube from the cylinder into the stub, then it will switch to high pressure air hose to my control room (about 250 feet) there I will have am electric valve controlled by multi function timer that has a tachometer function they have several options to control SSR's or small loads, there will be a proximity sensor on the alternator the tachometer will be settable trip the relay at any selected RPM.

So, at say, 275 RPMs the brake goes on then stays on until I reset it, or, in the event of upcoming nasty weather I activate it then reset when things are peachy again.

I'm sure it will all be a learning experience possibly including stomping around, yelling, throwing stuff and profanity, but in the end I think it can work.

News:

Author Topic: The brake for my seventeen footer. (Read 4673 times)