Trolley Design / Safety / Toppling.
Trolley Design / Safety / Toppling.
(OP)
I am after some help on the design of a trolley. We are buying out a standard trolley which can hold up to 500kg. Weight of the trolley is 114. The load the trolley will be carrying is 410kg.
I have attached a picture below. As you can see the load is quite tall. We have worked out the Centre of gravity using manufactured models of the valve/chute.
The chute is connected to the valve. The trolley will be wheeled in and fastened to the underside of the valve using bolts so the load is fixed.

Can anyone give me a hand on calculating the force required to topple the trolley. The trolley will only be moving a very short distance at walking speed.
I have attached a picture below. As you can see the load is quite tall. We have worked out the Centre of gravity using manufactured models of the valve/chute.
The chute is connected to the valve. The trolley will be wheeled in and fastened to the underside of the valve using bolts so the load is fixed.

Can anyone give me a hand on calculating the force required to topple the trolley. The trolley will only be moving a very short distance at walking speed.





RE: Trolley Design / Safety / Toppling.
Kyle
RE: Trolley Design / Safety / Toppling.
RE: Trolley Design / Safety / Toppling.
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The Help for this program was created in Windows Help format, which depends on a feature that isn't included in this version of Windows.
RE: Trolley Design / Safety / Toppling.
Cheers
Greg Locock
New here? Try reading these, they might help FAQ731-376: Eng-Tips.com Forum Policies http://eng-tips.com/market.cfm?
RE: Trolley Design / Safety / Toppling.
I'm a sparky by training, so set me straight on this if I need it.
Can't you do the "pebble under the wheel" scenario in two stages:
1. Compare the geometry with all four wheels on the floor and with the trolley perched on two wheels with the cg directly over the line joining the contact patches of the two wheels. Calculate the difference (h) in cg height above ground for the two scenarios (h)
2. Assume all the kinetic energy of the moving trolley gets converted into potential energy when the trolley trips. If
or is that a gross over-simplification.
A.
RE: Trolley Design / Safety / Toppling.
Cheers
Greg Locock
New here? Try reading these, they might help FAQ731-376: Eng-Tips.com Forum Policies http://eng-tips.com/market.cfm?
RE: Trolley Design / Safety / Toppling.
Nevertheless, it would seem to me that you could use the ramp stunt to analyze how high a ramp is required to tip the trolley.
However, the force required to tip the vehicle will depend on where the force is applied. You could certainly use the PE of the tipped trolley equated to the force*lever arm distance to come up with a range of forces, with the lowest force being applied to the very top of the structure.
TTFN
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RE: Trolley Design / Safety / Toppling.
I asked this question in the structural forum.
thread507-255357: Tipping Hazard
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JHG
RE: Trolley Design / Safety / Toppling.
RE: Trolley Design / Safety / Toppling.
RE: Trolley Design / Safety / Toppling.
RE: Trolley Design / Safety / Toppling.
What force engenders an equivalent moment will depend where it is applied.
What is Engineering anyway: FAQ1088-1484: In layman terms, what is "engineering"?
RE: Trolley Design / Safety / Toppling.
Off the wall but did you think of air lifts?
RE: Trolley Design / Safety / Toppling.
RE: Trolley Design / Safety / Toppling.
1) compliance in the scissor. While they are pretty stable in the Z direction, they aren't completely stiff in rotation and will allow the platform to tilt fore and aft; not much but it contributes
2) if the valve is not bolted to the platform it can slide under acceleration; the farther it slides the greater the moment on the platform and the greater the tilt, which can make it worse.
3) the footprint of the valve seems small. Even if the platform doesn't tilt, the valve might
4) if the floor is not level there will be a small component of tilt that can make things worse
5) unevenness in the floor can produce enough accelerations to vibrate the valve off the platform even when there isn't enough energy to tilt the item
6) check overhead clearances. Snagging that on a door frame or plastic drop opening could pull it loose
7) check the floor for holes and cover plates. drop a wheel into one of those and and the thing will go over.
Don't let this happen to you - http://science.slashdot.org/story/04/10/05/1557221...
RE: Trolley Design / Safety / Toppling.
The good news is the satellite was attached to the adapter plate. The bad news - adapter plate wasn't attached to the stand.
RE: Trolley Design / Safety / Toppling.
Yes it is a mobile scissor lift rate for 500kg so the load should be no problem and the load is centered according to manufacturer reccomendations.
The width between castors in the right view is approx. 600. The back castors are swivel the front are fixed.
The floor is relatively smooth no pits or debris but there is a slight fall for drainage.
Dgallup I agree I will make sure to address in a work instruction that the table must be lowered to its lowest height before movement. Its lowered height is 360 which will bring the cog below the top of the handle. Also making sure worker understands trolley castors must be inline before valve is fixed to trolley.
3ddave . Yes the valve will be bolted to the platform. The valve has the same flange on top as bottom and is cast stainless steel 316. I will check the floor don't think
there are any drains. I am going to make sure a route and a docking station is in place for the trolley.
The trolley will probably rarely get used it is only for 3/ 6 monthly maintenance and cleaning of the chute and hopper above.