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Bus Discussion => Bus Topics ( click here for quick start! ) => Topic started by: Nick Badame Refrig/ACC on March 30, 2007, 06:14:55 AM

Title: Linear Actuator
Post by: Nick Badame Refrig/ACC on March 30, 2007, 06:14:55 AM
I just saw this in the new spring master catalog of Northern Tool.

It's on page 121. It appears to be for small dump trailers and comes in 3 different sizes.

Does anyone know if this is also good for lifting the bed in my bus?

I have a good design in my head that would use 1 actuator do do it.

Thanks
Nick-

found the link at their web sit    http://www.northerntool.com/webapp/wcs/stores/servlet/NTESearch2?storeId=6970&N=0&Ntk=All&Ntt=linear%20actuator&Nty=1&D=linear%20actuator&Ntx=mode+matchallpartial&Dx=mode+matchallpartial
Title: Re: Linear Actuator
Post by: Ross on March 30, 2007, 10:21:30 AM
1350 lb capaity would certainly do it.  You'll probably need one for each side.  You can also try the site below.  They have more compact actuators.  The lift capacity isn't as high, but you don't need anything more than 150lbs or so.  You'll want something with about an 18" stroke.  The shorter you go, the more tension you'll put on the mounting points.

http://www.firgelliauto.com

Ross
Title: Re: Linear Actuator
Post by: H3Jim on March 30, 2007, 10:40:32 AM
Nick, did you want to lift the entire bed, or just have one end lift up for access underneath?

I used gas springs from Austin hardware, and I'm very happy with them.  They did the engineering for angles and mounting points for me. 
Title: Re: Linear Actuator
Post by: WEC4104 on March 30, 2007, 11:10:00 AM
A while back, I took a preliminary look at linear actuators and put them on my extended to-do list. As I recall, the key was to work the right combination of three interelated specs on the actuator: 1) Load capacity  2) stroke length  3) travel speed.  Then using these specs, you can play around with the the actuator placement location to see what is workable.

The three models listed on the page from your link all have a load capacity of 1350 lbs (pretty beefy) and a stroke speed of 8 mm/sec. (not blazing). Let's assume for discussion that your bed is hinged at the headboard and you want the acuator to lift the the foot of the bed. Picking some numbers, I'll say the bed is 84 inches long, you want the foot lifted 30 inches to gain proper access, and today it requires 80 lbs of upward force to lift it at the foot.

One actuator mounted at the foot of the bed would easily handle the weight, but a 30 inch actuator isn't listed, and if it was, it would take more than a minute and a half to raise.

The other extreme is to go with the shortest acuator listed (3 15/16")   If you still want the 30 inch raise at the foot, and the actuator is mounted straight up and down, it needs to be positioned about 11 inches from the headboard hinge. At that location, it will need to apply a little over 600 pounds of upward force, still easily within the unit's rated capacity.  The advantage is it will lift in a more reasonable 12.5 seconds. One disavantage is it is tougher on your headboard hinge.

All this assumes the actuator is mounted vertically and would need to be adjusted for an angular mount. Also adjust the numbers I used according to your own specific values.  But based on what I see, I don't seem a problem with what you are considering.

WEC
Title: Re: Linear Actuator
Post by: H3Jim on March 30, 2007, 11:19:30 AM
While an electric lift is cool, I think it only takes me a second or two to left the bed, and it stays up.  I  don't have to wait to get at what I want under there.  And a second or so to lower it.  Very convenient.
Title: Re: Linear Actuator
Post by: Nick Badame Refrig/ACC on March 30, 2007, 11:25:31 AM
Quote from: H3Jim on March 30, 2007, 10:40:32 AM
Nick, did you want to lift the entire bed, or just have one end lift up for access underneath?

I used gas springs from Austin hardware, and I'm very happy with them.  They did the engineering for angles and mounting points for me. 

Jim,
Yes, Just the foot end...
Nick-
Title: Re: Linear Actuator
Post by: Nick Badame Refrig/ACC on March 30, 2007, 11:30:48 AM
Quote from: Ross on March 30, 2007, 10:21:30 AM
1350 lb capaity would certainly do it.  You'll probably need one for each side.  You can also try the site below.  They have more compact actuators.  The lift capacity isn't as high, but you don't need anything more than 150lbs or so.  You'll want something with about an 18" stroke.  The shorter you go, the more tension you'll put on the mounting points.

http://www.firgelliauto.com

Thanks Ross,
The company's that I have been looking at have very high prices.
This Co. seems to be very reasonable...
Nick-
Title: Re: Linear Actuator
Post by: Nick Badame Refrig/ACC on March 30, 2007, 11:38:17 AM
Quote from: WEC4104 on March 30, 2007, 11:10:00 AM
A while back, I took a preliminary look at linear actuators and put them on my extended to-do list. As I recall, the key was to work the right combination of three interelated specs on the actuator: 1) Load capacity  2) stroke length  3) travel speed.  Then using these specs, you can play around with the the actuator placement location to see what is workable.

The three models listed on the page from your link all have a load capacity of 1350 lbs (pretty beefy) and a stroke speed of 8 mm/sec. (not blazing). Let's assume for discussion that your bed is hinged at the headboard and you want the acuator to lift the the foot of the bed. Picking some numbers, I'll say the bed is 84 inches long, you want the foot lifted 30 inches to gain proper access, and today it requires 80 lbs of upward force to lift it at the foot.

One actuator mounted at the foot of the bed would easily handle the weight, but a 30 inch actuator isn't listed, and if it was, it would take more than a minute and a half to raise.

The other extreme is to go with the shortest acuator listed (3 15/16")   If you still want the 30 inch raise at the foot, and the actuator is mounted straight up and down, it needs to be positioned about 11 inches from the headboard hinge. At that location, it will need to apply a little over 600 pounds of upward force, still easily within the unit's rated capacity.  The advantage is it will lift in a more reasonable 12.5 seconds. One disavantage is it is tougher on your headboard hinge.

All this assumes the actuator is mounted vertically and would need to be adjusted for an angular mount. Also adjust the numbers I used according to your own specific values.  But based on what I see, I don't seem a problem with what you are considering.

WEC

Hi Wayne,

Thanks for the figures!
the 11" from the head board is what I was thinking also.
I have SS heavy duty piano hinges on the head side, so it should be ok. And the platform is 3/4 cabnet grade plywood, I'll have angel iron supporting it also..
Nick-
Title: Re: Linear Actuator
Post by: Len Silva on March 30, 2007, 02:08:35 PM
I would be thinking of some way to pull a pin or otherwise disconnect the actuator in case of failure.  You know that if it's going to fail it will be when you are most desperate to get to the engine.
Len
Title: Re: Linear Actuator
Post by: Stan on March 30, 2007, 02:28:14 PM
There are two really nice linear actuators on all the old C band 10' dishes and usually free if you haul the dish away.
Title: Re: Linear Actuator
Post by: WEC4104 on March 30, 2007, 02:43:43 PM
Len's comment is a valid one, and it also triggered me thinking about a few other things....

First, I pictured myself in bed some morning catching the last couple of winks while my 3 young boys have been up since the crack of dawn. They decide it is time to get Dad moving and start the day. Knowing that Dad just installed this nifty electric bed thing, they start plotting ....   Hmmmmmm, gotta come up with a disabling procedure.

My second thought was less likely, but more serious.  The under bed compartment is easily large enough to hold a kid.  Today, my kids have no desire to lift the heavy bed so they leave it alone. Even if one of the brothers did hide in there, they could push their way out. Give them the electric lift option and I could see one climbing in while the "helpful" brother lowers it. (They've done stupider things)  Usually there is too much stuff stored in there to allow somebody to fit easily. Maybe I'm just being paranoid about the kid/old refridgerator type dangers. At least the bed would not be as air tight. Just thinking out loud.

WEC
Title: Re: Linear Actuator
Post by: Tony LEE on March 30, 2007, 03:26:08 PM
A double bed is heavy enough to trap even an adult under it so regardless of the type of lift assist it has there should be an (automatically deployed) safety prop to make sure it only lowers when it should.

I use gas struts but do have a broomstick to make sure it stays before I get too far underneath
Title: Re: Linear Actuator
Post by: akbusguy2000 on March 30, 2007, 03:31:34 PM
Nick, you might also want to have a look at some of these:

http://www.surpluscenter.com/sort.asp?UID=2007033017211967&catname=electric&keyword=EALD

tg
Title: Re: Linear Actuator
Post by: JackConrad on March 30, 2007, 04:37:36 PM
1350 lb capaity would certainly do it.  You'll probably need one for each side.  You can also try the site below.  They have more compact actuators.  The lift capacity isn't as high, but you don't need anything more than 150lbs or so.  You'll want something with about an 18" stroke.  The shorter you go, the more tension you'll put on the mounting points.

http://www.firgelliauto.com

Ross


Nick,
    That is where we bought our actuators for our bed. we use 2 of them (one on each side). I don't remember how far back from the hinge we placed them. We used 16" or 18" stroke. This raises the foot of the bed to the point it almost touches the ceiling fan.
Title: Re: Linear Actuator
Post by: Nick Badame Refrig/ACC on March 30, 2007, 07:08:13 PM
Thanks everyone for all the info and links!

Thanks Jack for the pics, they really help!

Nick-
Title: Re: Linear Actuator
Post by: Hartley on March 31, 2007, 09:13:54 AM
Here's an idea for safety...

Make the end of the actuator sit in a round tube sleeve on the end that extends. Then if you need to get it open and have
no power you can lift the bed up and the actuator tube will fall out of the sleeve. (no bolt or pin).

Had to make something like that for a guys 10 foot satellite dish jack so in a really high wind the dish would flip over against a stop bar at the other end of rotation. ( it was 27 feet up in the air too! ) That was a wierd project but the idea worked.
Title: Re: Linear Actuator
Post by: Nick Badame Refrig/ACC on March 31, 2007, 09:53:12 AM
Quote from: DrDave-Reloaded on March 31, 2007, 09:13:54 AM
Here's an idea for safety...

Make the end of the actuator sit in a round tube sleeve on the end that extends. Then if you need to get it open and have
no power you can lift the bed up and the actuator tube will fall out of the sleeve. (no bolt or pin).

Had to make something like that for a guys 10 foot satellite dish jack so in a really high wind the dish would flip over against a stop bar at the other end of rotation. ( it was 27 feet up in the air too! ) That was a wierd project but the idea worked.


Great Idea Dave!
Thanks..

Nick-