| Author |
Message |
joe shelton (68.237.133.66)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, March 04, 2004 - 8:55 am: | |
I have been studying the air bag leveling system and the stationary leveling systems folks have made or bought. I keep looking for a way to use the exsisting leveling valves with out installing a bunch of by-pass valves, pumbing & control valves. I think I'm close to a simple solution. Any one else looking into this?
Joe 4106-2119 |
grant (208.187.245.73)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, March 04, 2004 - 9:06 am: | |
I would be very interested in what you come up with. I too would like a more simple system on my bus.
Thanks
Grant 4517 |
joe shelton (64.223.154.89)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, March 04, 2004 - 10:21 am: | |
I am currently pulling the parts together to try out my idea. It will probly be a couple of months till completion. If you want more info as it nears completion send me an e-mail with 'Bus Leveling' in the subject line and I'll keep you posted.
Joe 4106-2119 |
Geoff (Geoff) (66.238.120.17)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, March 04, 2004 - 10:33 am: | |
I installed a manual over automatic leveling system in my bus and understand what is involved-- why don't you give us your idea on a simpler system? Or is it a secret? |
joe shelton (64.222.145.101)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, March 04, 2004 - 11:54 am: | |
No it's not a secret. I just don't know if it will work. But what it basicly involves is adjusting the length of the leveling valve link. The link will be spring loaded to the automatic or running length and can be shortened manualy (without going under the bus with wrenches).
Joe 4106-2119 |
Sean Welsh (Sean) (64.81.73.194)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, March 04, 2004 - 1:50 pm: | |
We did exactly this on our Neoplan....
The Neoplan air suspension layout makes it extremely difficult to build an air-operated leveling system. The coach had such a system (HWH) when we bought it, and it cause so many problems that we ripped it out. (It's for sale if anyone wants it...)
Instead, we replaced the three fixed-length links with 24-volt linear actuators. Our suspension has about 6" total travel up and down, so we used actuators with 6" of travel. The actuators we chose have feedback potentiometers in them, and I constructed a simple circuit to allow me to return each actuator to its "ride height" position.
The linear actuators are about 14" long in the "centered" position, and the links they replaced were only about 8" long. We had to modify the mounts on both ends to accommodate this, which involved fabricating new lever arms for the valves.
Everything works perfectly in the shop, but we have not yet had the coach back out on the road to make sure normal driving operations are not affected. I have no reason to suspect we will have any problems, though.
I will try to get some pictures of this posted on our web site in the next week or so.
-Sean |
Telestar Emery (142.59.209.189)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, March 04, 2004 - 6:48 pm: | |
Anyone ever tried a hydraulic ram system?? Just curious. Have a day everyone. Cheers, Emery |
Sean Welsh (Sean) (64.81.73.194)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, March 04, 2004 - 10:09 pm: | |
OK, I posted a picture of our setup. It's at:
http://odyssey.smugmug.com/gallery/77568/2/2688324
and the subsequent two photos.
-Sean |
FAST FRED (65.154.176.214)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, March 05, 2004 - 5:29 am: | |
I haven't installed it yet but my leveling system will simply be heavy duty , locking push pull cables connected to the leveling valve.
The loads to operate the valve are very low , a few pounds at most, so well within the ability of a series 40 marine shift cable.
The only hassle I envision is the cable has only 4 inches of travel , so the controll arm will need to be drilled .
I plan on 3 short cables , one to lift/lower front, the others in rear to level side to side.
Only 3 cables at $50 each would be a delight , compared to miles of tubing , wiring , and extra mechanical/electrical parts hung out under the coach for slush to work on.
Only disadvantage I forsee is it wont be possable to lower coach underway from drivers seat to slip under low underpass or to attempt better milage by dragging less air. So will install front air dam.
Leaving the system almost totally stock , able to adjust it self to varing loads , factory engineering style seems the simplest and safest method.
Hope it works , I'm colecting parts now for a summer attempt.
FAST FRED |
Jim Wilke (12.46.52.74)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, March 05, 2004 - 10:26 am: | |
Hey Fred,
Your system sounds like a winner. But you've got to make the valves themselves pivot where they are bolted to the bus. Then attach the cable to the valve, not the arm. Then when you adjust the cable, you raise or lower the end of the valve, making it raise or lower the bus.
If you use 1 short & 2 long cables, you could have the control levers at the "helm", allowing you to make the changes from there. An old shifter control would have a detent for (Neutral) the normal ride height. Four inches of travel would be plenty that way. You'd want good cables, not cheap ones to reduce the slop, or you could put springs at the valves to assure the cable came back to the right spot.
You could also use pneumatic or hydraulic controls instead of cable if you want to spend more $$.
By George, I think you've got it!
Jim-Bob |
Randall Hays (69.4.194.100)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, March 05, 2004 - 12:04 pm: | |
Has anybody thought of taking an electric window actuator and putting it in place of the arm? you could set it at the middle and then when you went up or down it would be in place for where you want it? I have an MCI-8 and just wondering out loud if it would work? |
Sean Welsh (Sean) (64.81.73.194)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, March 05, 2004 - 4:09 pm: | |
A couple of people have asked what my system cost... some day I hope to post all the details on my site, but for now I'll give the salient points:
I bought the three linear actuators on eBay for $50 each. I built the control box using about $25 in parts, most of which also came from eBay.
Miscellaneous hardware to install the actuators (swivel joints, threaded rod, etc.) as well as about 4-5 hours of labor, including welding, were supplied by my prime contractor Infinity Coach, so I don't have an individual breakdown -- plus, unless you have a Neoplan Spaceliner, you will need different miscellaneous hardware than I did.
For the record, I liked Fred's idea of manual cables, but, due to the weird position of our cockpit and the number of 90s in the routes to the valves, this would not work for us.
The Spaceliner, by the way (and many other Neoplans) has only one ride height valve in the rear, and two up front -- the reverse of many other brands.
-Sean |
Geoff (Geoff) (66.238.120.122)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, March 05, 2004 - 10:37 pm: | |
It's been a few years since I asked about making up a system like Sean has, and he is the first one I know of that has actually made up an actuator system that works the leveling arms (congradulations!). Looking at your pics, Sean, I see that I would not have enough room for your system. So anyway, I went the electric solenoid route, and I am satisfied with the system. It works very fast up or down, and I can level my bus out from the driver's seat in a minute or two. I've had it for about three years now with no breakdowns.
--Geoff
'82 RTS CA |
John Bessette (65.73.247.166)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, March 05, 2004 - 10:48 pm: | |
I think Jim and Fred got it. move the valve and when the bus goes up or down it will come back to the off position and hold it right?
John
4106 |
FAST FRED (63.233.189.23)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, March 06, 2004 - 5:16 am: | |
My system would anchor the cable housing in a position similar to the tiny coat hanger wire that now references the coach how high it is.
Then extending the inner cable would just have the coach ride higher as the reference was changed ditto for lower.
Still trying to think of a Simpler system (KISS) but have stopped with this.
FAST FRED |
JIm Bob (152.163.252.163)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, March 06, 2004 - 10:35 am: | |
Fred, the only problem I see with connecting the cable to the other end of the arm is that the "little coat hanger wire" attaches to the axle. So your cable's outer jacket would have to attach to the axle & the inner end to the air valve arm. This would have the cable pointing up which would encourage water & crap to get past the flimsy seals & down inside the cable, ultimately making it bind. Also being attached to the axle would have the cable seeing a lot of movement & wear. These are not fatal flaws but I'm thinking it could be done better somehow.
This morning I was thinking about this design & I thought: Why not reverse the valve & mount it on the axle, then connect your cable as the attachment point on the bus? This would require using hydraulic type hoses for the air due to the movement & flexing which I think would fatigue Synflex tubing at the air valve fittings. Or Synflex might be fine if you made large loops & clamped each end so it didn't flex at the fitting.
I still think making the valve's body pivot is the cleanest way. All original design parameters retained, very little flex on air hoses & control cable assembly. It would just take a nice, sturdy pivoting bracket between valve & bus. Also have to provide big radius for bends in the control cable. |
Sam Sperbeck (204.248.119.254)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, March 06, 2004 - 11:02 am: | |
Hi Sean,
With your system of height control, the air has to pass through the height control valve to change the height, if I understand how it works. How long does it take your bus to go from road height to full height? It would seem to me that the travel would be fairly slow because of the small opening in the height control valve, not that it is a big thing, just wondering.
Thanks, Sam Sperbeck
La Crescent, MN |
Sam Sperbeck (204.248.119.254)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, March 06, 2004 - 11:21 am: | |
Hi Joe,
If I am understanding your idea correctly, you will only be able to inflate the air bags. If that is the case you will only be taking advantage of half the travel of the suspension. With Sean's method he takes full advantage of the suspension travel by being able to both inflate and deflate, IF I am understanding how his system works. How do you plan to manually shorten the link? I sure like the exchange of ideas on this subject because I am not totally satisfied with my system of eliminating the height control valves and useing air-ride seat valves, although that eliminated the bus saging unequally from leaking check valves in the height control valves, and allows me to level when parked.
Thanks, Sam Sperbeck
La Crescent, MN |
Sean Welsh (Sean) (64.81.73.194)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, March 06, 2004 - 1:17 pm: | |
Sam,
Yes, all the adjustment in my system is through the factory ride-height valves. These are the delay type, but they are fairly fast after that, because they are intended to be dynamic when traveling (they actually keep the bus from "rolling" excessivley when going around corners).
I think the orifices in these valves are 3/8" (well, the metric equivalent...). This is actually the biggest reason why we took the HWH system out -- the changeover valves on that system had 3/16" orifices, so air flow to and from the bags was throttled down to 1/4 what it should be, and the bus heeled over something fierce when cornering at speed.
Haven't timed it, but I would guess around 5-7 seconds for the bag to come either up or down fully from center (about 3" of travel). The LA travels at about one IPS, so leveling the coach requires some patience -- make a small change with the switch, then wait for the bag to catch up, repeat as necessary.
-Sean |
joe shelton (64.223.179.218)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, March 07, 2004 - 10:43 pm: | |
I also looked into using the linear actuators but wanted something simpler. Also I looked at Sean's photos and don't think it's a real bus. Too clean! Looks really nice Sean.
My plan will change the length of the valve link. I've got the consept drawing done. Now just to build it. It's realy simple. The drawing is a PDF if anyone would like to see. I am planning on only adjusting while parked. Ajustments to be made at rear wheel wells and one of the forward. |
Peter Broadribb (Madbrit) (67.136.81.42)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, March 08, 2004 - 5:01 am: | |
Since I only have one height control valve on my Freightliner, after reading all the previous posts, I think I will attached the "fixed" end of the wire link from the control valve to a Morse cable at its midpoint in travel. Then I can either move the Morse cable lever one way or the other to raise or lower the rear of the vehicle and simply move it back to center for stock suspension.
Other than this, I thought about using the servo control from a remote control model aircraft or boat to do the same job of moving the fixed point of the height adjuster system
Peter. |
FAST FRED (65.154.176.246)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, March 08, 2004 - 5:59 am: | |
The point was made and correct that the cable housing end will be facing up ,(cable housing clamped where the coathanger was , moving end attached to hight adjusting arm) so might be subject to contamination.
My sugestion is to soak the cable in 100% antifreez , it will penitrate well and leave a nice slipery residue thats not affected by water , when the seal wears out.
If you get it installed before I finally find time , please post your results!
FAST FRED |
Geoff (Geoff) (66.238.120.25)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, March 08, 2004 - 9:10 am: | |
My experience with Morse controls is that they are sloppy-- they would not be very good at returning to dead center to set the normal ride height. Plus is anyone actually going to run cable to the driver's area and have the three controls there? A bus is not a boat. Electrical controls is the way to go for clean installation, whether they are operating electric solenoids or linear actuators.
--Geoff
'82 RTS CA |
joe shelton (64.223.183.138)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, March 08, 2004 - 11:28 am: | |
Geoff, You say you went the electric solenoid route. What is that route any way? Please discribe. Joe |
Peter Broadribb (Madbrit) (67.136.118.101)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, March 08, 2004 - 11:54 am: | |
Geoff,
Morse control cables are used extensively in many industries other than boats, and in applications where precision adjustments are required. Gear selector cables and throttle cables for example.
I also fail to see why, in my application, I would require 3 cables, as I said I only have one valve.
In other applications it could be a problem but no more of a problem than throttle cables can be.
Anyway, if that is a concern then consider the other option I suggested, using a servo control box.
Peter. |
RJ Long (Rjlong) (66.229.97.200)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, March 08, 2004 - 12:17 pm: | |
One of the things that concerns me about Fast Fred's Morse cable idea is that the leveling valve linkage is in constant motion from normal axle movement as you're running down the highway. That's one of the reasons that these valves have some delay built into them.
It seems to me that a fixed cable attached to moving linkage may have an adverse effect when traveling, such as bending the linkage, which might possibly affect the vehicle's handling. Just thinking at the keyboard, as no one's mentioned this before, or maybe no one's thought about it. . .
FWIW,
RJ
PD4106-2784
Fresno CA |
Peter Broadribb (Madbrit) (67.136.108.200)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, March 08, 2004 - 1:02 pm: | |
RJ,
I was going to attach the Morse outer cable to the fixed chassis point and then attach the control wire to the end of the Morse cable. Effectively making a movable fixed point. This will have a short end to the Morse cable and should not be any less solid than the original setup. As the control wire runs vertically and the Morse cable will do the same, I don't see much chance of any problems. The levelling valve is very easy to move and needs little force to activate it and it rsponds quick enough to adjust to the factory requirements. I have used the valve to lower the truck to get in the workshop and also to raise it to put the frame on jack stands too. Works just fine, for my application, but I may still research the remote control servos further or even use a linear actuator, if I can find one small enough to fit.
With one of the linear actuators, how does one control the position of the ram? There must be some sort of pulse counter like they use on the C Band satelite dishes so the control knows exactly where the ram is in its cycle?
Peter. |
Sean Welsh (Sean) (64.81.73.194)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, March 08, 2004 - 1:19 pm: | |
Peter,
The actuators I bought have built-in linear taper potentiometers for positional feedback.
I built a simple circuit using voltage comparators and some LEDs to show me if the actuators are set HIGH or LOW from their center (ride-height) position. With this setup I can quickly and easily return the actuators to the "travel" position.
Actuators are also available with pulse generators, but I opted to go the potentiometer route because that meant that my control unit could be "stateless" -- the pots return the same value regardless of how long the system has been without power. With a pulse counter, your controller needs to "remember" how many pulses away from center you are.
-Sean |
Peter Broadribb (Madbrit) (67.136.108.200)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, March 08, 2004 - 1:47 pm: | |
Sean,
"I built a simple circuit"
Easy for you to say........ LOL.
Just a simple circuit to you is a nightmare to me. I would not know where to start. I need to just be able to buy an actuator with such a system and be done, I don't have the time to learn all about components and design a circuit. Thanks for the info but on my old C Band system, it did not forget where it was when the power went out. The control knew where it was last positioned suchas G-12 and that is was X amount of points away from the next satelite.
So what do you suggest for us non-electronics wizz-kids?
Peter. |
Sean Welsh (Sean) (64.81.73.194)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, March 08, 2004 - 2:42 pm: | |
Peter,
I'd be happy to share my circuit diagram with everyone, but it will take me some time to get it in a format I can post.
Beyond that, I don't have a good suggestion -- I did it this way because, to me, it was the simplest way to go. With some creative thinking, you may find a different way that is simpler for you.
Just FYI, the potentiometers add about an inch to the overall length of these actuators. I was trying to save space, so I went through a whole round of thinking about other ways to detect position. In the end, I decided it was easier to give up the inch than invent a different mechanism.
That being said, among the things I considered were various types of switches positioned on sliding arms along the actuator travel, such as magnetic reed switches (such as one would have in an alarm system).
As for your C-band control, I would guess it had some type of non-volatile memory in it to maintain the state. Any type of cicuit with memory in it was way more work than I wanted to do for this project.... My circuit simply compares the value of the feedback pot to a pair of adjustable trimmers ("reference" pots) that are set for the ride height of the bus.
-Sean |
Geoff (Geoff) (66.238.120.141)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, March 08, 2004 - 2:46 pm: | |
Joe--
Perhaps I should have been clearer, the electric solenoids are what people refer to as "Skinner valves"-- low voltage opens the valve to release or add air to a system. Using three solenoid valves, you can shut off the automatic leveling valves and add or release air to raise or lower the coach. While driving one of the valves stays open so the automatic levelers work as before. Three solenoid valves at each leveling valve will accomplish this. Once you get into this there are debates on which type of solenoid valves to use, whether they be check valve type, ball valve type, or spool valve type. I am using spool valves to isolate the leveling valves and using electric check valves to lower and raise. The drawback to this system is the valves allowing air to leak down over time, mine hold the bus in position for a few days to a week which is satisfactory for my use. The push-pull knob leveling system holds air better but is slow and eliminates the automatic levelers, so I did not want that system (plus the "kits" sold by a supplier, that we see advertising all the time, are way overpriced-- if you go this route, buy your own parts!).
--Geoff
'82 RTS CA |
FAST FRED (63.234.20.212)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, March 09, 2004 - 5:24 am: | |
Morse Cable was used as a generic term like 8D ,so folks could get a mental picture.
There are FAR finer cables with up to 3/16 inch SS core that should take the constant jiggeling of the hight valve lever.
They also lock in any position and I have seen cables that could take my weight when locked.
Simply a matter of using a good clevis arangement. OTS $9.00.
But the good cable is a bit more.
FAST FRED |
ggo4 (65.1.55.153)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, March 09, 2004 - 1:40 pm: | |
4 gages 4 control valves and 50' of 3/8 line..few hundred thousand miles latter still works perfect...goes by where you shop $100. more or less ...Works every time...gg |
Sean Welsh (Sean) (64.81.73.194)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, March 09, 2004 - 5:27 pm: | |
"...few hundred thousand miles latter..."
Hey, gg -- what's the point of having a leveling system if you just drive continuously and don't ever park ? :-) |
gg04 (65.1.55.153)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, March 09, 2004 - 5:52 pm: | |
See the dodadded ones all the time mostly ,parked at some repair shop . goes by if you want to use it or just build and talk about it..real world highways kill dodads...just home from a 3000 mile loop.. Why make it more complicated ? Still belive in KISS..Just my opinion...350000 miles later.. gg 60 4104 671ta ddec....third and last bus...LOL |