Converting Lbs To Newton Metres

[CX16]

Hi
I have converted my front passenger single seat to sit on the twin seat base ( I need the storage). This was achieved by puting a flat plate on the top of the double seat base and then cutting down and attaching the single seat. The plate hinges at the front and doesn’t have the benefit of the original slide and tilt mechanism. It is therefore a bit heavy, in fact it requires a force of over 30lbs to lift it, so I am planning to put in a ram to help with the lift. Most rams appear to work in Newton Metres, does anyone know how to work out how powerful a ram I will need ? Thanks for your help.

 

[andys]

Hi
I have converted my front passenger single seat to sit on the twin seat base ( I need the storage). This was achieved by puting a flat plate on the top of the double seat base and then cutting down and attaching the single seat. The plate hinges at the front and doesn’t have the benefit of the original slide and tilt mechanism. It is therefore a bit heavy, in fact it requires a force of over 30lbs to lift it, so I am planning to put in a ram to help with the lift. Most rams appear to work in Newton Metres, does anyone know how to work out how powerful a ram I will need ? Thanks for your help.

Convert lb ft to N m - Conversion of Measurement Units

 

[Dellmassive]

,not done this, but i would imagine,

if it's 30lb to lift.

You could get a ram that supplied 20lb or 25lb of pressure leaving 10lb or 5lb to be applied by hand to over come the 30lb required

Then Google the conversion, ie "what is 20lb in nm"

Then try that ram, might be s bit of trial and error.

 

[WheelieBealie]

You'll need to know the lever length of the ram too, you cannot directly convert lbs (pounds) to Nm (Newton Meters), because Nm is is a torque i.e. an applied force acting at a given lever length and lbs is just the applied force part.

 

[andys]

You'll need to know the lever length of the ram too, you cannot directly convert lbs (pounds) to Nm (Newton Meters), because Nm is is a torque i.e. an applied force acting at a given lever length and lbs is just the applied force part.

Oops you're right sorry, I speed read the post while getting ready for work and didn't notice that it wasn't a direct conversion from lb/ft to Nm that was required.

 

[CX16]

Hi folks, I tried buying a ram that was described as 140Nm but I couldn’t compress it at all, so I’m guessing it’s going to be a lot less than that, I was hoping to get a closer idea of the force required before buying the next set of rams. The ram has to have a compressed size of 300mm.

 

[Pete C]

What is the distance from the hinge to where you lift it ?
And how do you know if takes 30lbs of force to lift it ?
Also, any chance of a photo to help visualise it ?

Pete

 

[Pete C]

And can you post a link to the type of ram you want to buy please.

Pete

 

[CX16]

Hi Pete
My van is away at the moment, so sorry no photos. In answer to your questions.
1. Front to back depth is 19” standard seat base size.
2. I put a suitcase spring balance on the back of the seat, where it sits on the base and lifted straight up, just over 30lbs appeared on the dial, so I thought I would start from there.
I also measured down inside the seat base and there is about 300mm of space to put a compressed ram in. (When the kid is closed) I am thinking of using the type of ram you find holding the bonnet open on the T6. Hope that helps.
Ian

 

[Pete C]

Ok, so 30kg is a force of 300N.
Assuming the distance from the hinge to where you lifted is 19" (which is 48cm approx), then the torque you applied is:

300 * 0.48 = 144 Nm

I don't understand why the ram supplier is quoting a Nm value i.e. torque, when it actually exerts a force. The torque it exerts is a product of the force it exerts and the distance from the hinge that you mount it, which they don't know. I have had a look at a few websites, and struts for car boots etc seem to rated by force ie Newtons or N, not Nm.

On the basis that you mount a strut to push the lid at the furthest point from the hinge, then you need a strut rated at the force you exerted to lift the seat i.e. approx 300N. Mount it closer to the hinge, and you have to increase that amount.

However you mount the ram, you are going to have to fabricate pretty substantial mounts

Can someone please check my assumptions.

Pete