Moving a centre point

[God mode restorations]

Hi guys.
A question for you engineering chaps out there.. I don't have engineering back ground.just a guy that likes fab work . I also have dyslexia so it's difficult to sometimes explain what I am trying to do.I have a few posts in what you have made today thred that shows the tarmac shoots I am making for my lorry.below is a couple of pictures. The long flat bar at the bottom has a centre Mark. I want to move the centre point between the flat plate and the half radius piece. What effects will it have on moving the shoot up and down.hope you understand what I am asking.The Centre Point Is For An m22 Bolt.

 

[Seadog]

If you post a drawing of how it's intended to be used it might help.

 

[God mode restorations]

If you post a drawing of how it's intended to be used it might help.

Will do..

 

[pedrobedro]

If you shorten the lever it will make it harder to lift if that is what you are doing. A picture of the complete apparatus would give more idea.

 

[God mode restorations]

OK. Picture is the almost complete shoot and extension handles in closed position and extended position.

 

[God mode restorations]

Reason in moving the centre point down is so the handle in the closed position don't foul the m22 bolt.

 

[God mode restorations]

The closer the pivot bolt is moved toward the door thingy the easier it'll be to pull the handle, but the tradeoff is the door won't open as far.

Yes I understand that one. It's moving top to bottom not closer to the door.

 

[God mode restorations]

I have worked it out guys.sorry if it comes across confusion...cheers thoe.

 

[God mode restorations]

Show us then, because I haven't worked out what you're doing!

OK. Give me a bit I will post .am out at the moment getting bolts.

 

[God mode restorations]

OK guys. I have a tarmac lorry that I am making a new tailgate and shoots for.this is the picture of the old gate.

 

[God mode restorations]

My new shoots will be opened and shut via a leaver that can be extended if need.the shoots slide up a down in runners that I haven't made yet.the big m22 nut in the picture below is my original location for the pivot point.the back of the pivot point is welded to the side of the tailgate .

 

[God mode restorations]

Now.my extended leaver in the closed position would foul the m22 nut. So I have moved it down to the point in the picture below.

 

[God mode restorations]

In moving it down I didn't know if would up set the way the forces applied to raise or lower the shoots.

 

[Seadog]

Ah ha! If you move the lever arm bolt to the right you'll increase leverage, but only if there is a stop on the lower section for the folding part to bear against. If you move it to the left, you'll lose some leverage and start to bring the lever nearer to a vertical and probably unusable position.

 

[God mode restorations]

Ah ha! If you move the lever arm bolt to the right you'll increase leverage, but only if there is a stop on the lower section for the folding part to bear against. If you move it to the left, you'll lose some leverage and start to bring the lever nearer to a vertical and probably unusable position.

Yes.. when the lever is full extended there is a couple of bolts to lock it in to position. Have not drilled them yet.and when not in use they fold away .but I didn't realise they would foul the m22 nut once when folded.so I put the half radius bit in to move the nut ferther away from the arm allowing them to be closed right up....

 

[waddycall]

I'm wondering if it might be a bit unstable with the pivot offset. When you pull the lever it'll try to rotate the handle away from the tailgate unless there's a large surface area for the half radius part to rotate on. Looks very tidy.

 

[knighty]

not sure what the pieces are called, so I'll call the bar that's attached to the shoot door the 'main bar' and the other bar the 'leaver bar'

if you shorten the main bar, so it ends just after the pivot bolt where it joins to the leaver bar

you could fix weld a bar on the edge of the leaver bar, to the left of the pivot nut(bottom edge looking at the photos)

that way you'd have more contact area between the two bars, so they'd be stiffer/stronger

you could even make it a U shape, so the leaver bar hooks around the main bar ? - that would be nice and strong :-)

 

[God mode restorations]

I'm wondering if it might be a bit unstable with the pivot offset. When you pull the lever it'll try to rotate the handle away from the tailgate unless there's a large surface area for the half radius part to rotate on. Looks very tidy.

Yes.. you got it.that's what I been trying to explain. Offset..sorry for not using the correct words.and yes there will be a large surface radius for it to rotate against.

 

[waddycall]

Depending on how high the gate lifts, offsetting the pivot may mean the gate gets pulled sideways more as the lever goes past horizontal. As long as the gate is tall enough it should still slide in the runners ok. It'll always happen of course but it'll be exaggerated by the offset.

 

[God mode restorations]

The more offset I have the more it will try to rotate the handle away....the m22 will be a solid shaft that's threaded one end and a tube that fits snug over it with some grease points.the length of the shafts will be about two inches long with a large radius serface for it to work on.