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Science Forum Index » Mechanics Forum » scissor lift design help
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| mo |
 Posted: Sun Apr 13, 2008 2:41 pm |
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Anyone have any info or links to scissor lift design. I'm looking at
lifting 400lbs total to a height of 7ft with base of 66 " by 36". Any
ideas? Preferably with a lead screw for lifting or hydraulics, can't
use electival power.
Thanks. |
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| mo |
| Posted: Sun Apr 13, 2008 4:07 pm |
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David
Power is manual, the estimated weight of scissor lift and platform it
lifts is 400lbs.
Both of which arre aluminium. the load bearing will be in the scissor
arms which will be designed to 2000 lbs.
It has to be a scissor due to collapse height and storage needs.
On Apr 13, 6:47 pm, "N:dlzc D:aol T:com \(dlzc\)" <dl...@cox.net>
wrote:
Quote: Dear mo:
"mo" <mot...@gmail.com> wrote in message
news:780f3b3f-3016-4463-bc1c-bdfc4d120f95@v26g2000prm.googlegroups.com...
Anyone have any info or links to scissor lift design.
I'm looking at lifting 400lbs total to a height of 7ft
with base of 66 " by 36". Any ideas? Preferably
with a lead screw for lifting or hydraulics, can't
use electival power.
How do you intend to power this?
Can you use an overhead crane affair?
Is the 400 pounds "live load"? (People, or animals that move
around.)
I replaced a scissor lift system, because the bearings were
nearly impossible to properly service. I did it with direct lift
at each end of a table, like a hammock. I used a simple op-amp
circuit (at first) to correct for tilt in the table. But I used
electricity.
David A. Smith |
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| mo |
| Posted: Sun Apr 13, 2008 7:45 pm |
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Guest
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On Apr 13, 9:03 pm, "N:dlzc D:aol T:com \(dlzc\)" <dl...@cox.net>
wrote:
Quote: Dear mo:
"mo" <mot...@gmail.com> wrote in message
news:854c7da6-86b8-4f6d-b99f-90edca5e525d@w8g2000prd.googlegroups.com...
Power is manual, the estimated weight of scissor
lift and platform it lifts is 400lbs.
Both of which arre aluminium. the load bearing
will be in the scissor arms which will be
designed to 2000 lbs.
It has to be a scissor due to collapse height
and storage needs.
OK, so what kind of mathematical model to you have knocked up so
far? Each "leg" of your scissor is at most 66", and you need a
72" lift. So you will have to have two pairs, right?
How tight a stack (vertical) do you need?
I'm afraid aluminum in toto will be inadequate, but then I never
did much like aluminum. Too much analysis required...
David A. Smith
Each arm overall is 64" pin to pin is 61". Yes it is two pairs , I
have cad mock up of tow cylinders attached to base and then to second
pair of arms, when folded the cyliders are at 9 degrees to horizontal,
i calculate loading to 1917 lbs at thisposition so 958 per cylinders.
I plan on use 4x2 Al 6061.
I need help with bearing /bushing selection and force calc . |
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| N:dlzc D:aol T:com (dlzc) |
| Posted: Sun Apr 13, 2008 8:47 pm |
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Guest
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Dear mo:
"mo" <motina@gmail.com> wrote in message
news:780f3b3f-3016-4463-bc1c-bdfc4d120f95@v26g2000prm.googlegroups.com...
Quote: Anyone have any info or links to scissor lift design.
I'm looking at lifting 400lbs total to a height of 7ft
with base of 66 " by 36". Any ideas? Preferably
with a lead screw for lifting or hydraulics, can't
use electival power.
How do you intend to power this?
Can you use an overhead crane affair?
Is the 400 pounds "live load"? (People, or animals that move
around.)
I replaced a scissor lift system, because the bearings were
nearly impossible to properly service. I did it with direct lift
at each end of a table, like a hammock. I used a simple op-amp
circuit (at first) to correct for tilt in the table. But I used
electricity.
David A. Smith |
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| Back to top |
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| N:dlzc D:aol T:com (dlzc) |
| Posted: Sun Apr 13, 2008 11:03 pm |
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Guest
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Dear mo:
"mo" <motina@gmail.com> wrote in message
news:854c7da6-86b8-4f6d-b99f-90edca5e525d@w8g2000prd.googlegroups.com...
Quote: Power is manual, the estimated weight of scissor
lift and platform it lifts is 400lbs.
Both of which arre aluminium. the load bearing
will be in the scissor arms which will be
designed to 2000 lbs.
It has to be a scissor due to collapse height
and storage needs.
OK, so what kind of mathematical model to you have knocked up so
far? Each "leg" of your scissor is at most 66", and you need a
72" lift. So you will have to have two pairs, right?
How tight a stack (vertical) do you need?
I'm afraid aluminum in toto will be inadequate, but then I never
did much like aluminum. Too much analysis required...
David A. Smith |
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| Back to top |
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| dlzc |
| Posted: Mon Apr 14, 2008 11:16 am |
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Guest
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Dear mo:
On Apr 13, 10:45 pm, mo <mot...@gmail.com> wrote:
...
Quote: Each arm overall is 64" pin to pin is 61". Yes it is two pairs,
I have cad mock up of tow cylinders attached to base and
then to second pair of arms, when folded the cyliders are at
9 degrees to horizontal, i calculate loading to 1917 lbs at
thisposition so 958 per cylinders.
I plan on use 4x2 Al 6061.
I need help with bearing /bushing selection and force calc .
Limit your model to the very lowest triangle. Have the downward
force, and an unknown (for now) couple acting at the apex of the
triangle. You have a "four bar mechanism", and I suspect you can find
your exact solution on the internet. You are describing a "crank-
slider".
Personally, I like the cylinder to act horizontally. It minimizes
stroke, and the vertical component at the deck is always down,
supporting weight. If you push into the "fulcrum", the parallel
members are in tension, fighting the cylinder(s).
David A. Smith |
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