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Vertical Sound Cart Weight Support


saadasound

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So, I just put together this cart last week for a show I started this week. It's working pretty well so far, but the main issue is that its top heavy and the wheels don't seem to be spaced the right way in order to support the weight when pushing. Of course pushing from the smart wheels side is easier, but it's tough getting it moving from a static position.

 

I was thinking to maybe outrig the smart wheels so they are a little further out from the base, as well as getting some larger back wheels to help getting over bumps and such. Anyone have and thoughts or ideas on how to get this done? 

 

Thanks so much!


Steve

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One thing is the casters are so big that it takes quite a push to get them aligned to the direction you want it to go; especially with all that weight.

 

More air in the tires will lower the friction and make it easier to move.

 

I can't tell if the front casters are pneumatic, but that would make it a bit of a tough go even if they are fully inflated.

 

The angle of the red handles is not helpful. You can't get a proper grip on those handles to push the cart. There's more of a lifting action in the back and a downward force in the front with that angle, which doesn't help. I would guess those handles make it a bit cumbersome to push properly.

 

If you push from the caster side, it seems it would go pretty good, but steer awkwardly.

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Generally carts push better when the "smart" wheels are at the rear, right in front of the handles, as on a Magliner, and you push the cart in front of you (as opposed to dragging it behind you).  Was your plan with this cart that you'd tilt it back onto the big wheels with those red handles, and roll it with the smaller wheels off the ground?   Or is it too heavy for that?  If you are planning to do a "2 wheel" roll then bigger wheels would really help with getting over cables etc.   If the cart is heavy enough that you really can't safely roll it on 2 wheels then I'd say you might want consider bigger wheels all around.   Do you need such wide tires?  I ask because I recall those wheels as being pretty heavy themselves.   Unless the cart is really heavy, you might even consider solid wheels.  I've used those for years on a 4 wheel Magliner cart, and even heavily loaded they work great.  They are also much lighter that the pneumatic wheels.  Going to bigger wheels would mean remounting the axles, or even using separate axles for each wheel.

 

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With the rear wheels behind the cart and the casters under the cart, most of the weight is on the casters. That makes it all the tougher to get it moving. Also, since the casters are close together, the cart has a narrow wheelbase which  makes the cart less stable; especially with most of the weight on them.

 

The goal should be to get at least half the weight on the rear wheels or even more. The casters on my cart are such that the cart tilts back a bit so the center of gravity is shifted back to get more weight on the rear wheels. Thinner, larger diameter wheels on the back that have the axle closer to the cart will also help.

 

That's why 2-wheel dolly's like the one you are using have the wheels so far back - it gets the center of gravity on top of the wheels when you tilt it back. But that is to your disadvantage for the cart you have designed - assuming you want to operate it as a 4-wheel dolly.

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16 hours ago, Philip Perkins said:

“Generally carts push better when the "smart" wheels are at the rear, right in front of the handles“

I worked as a IATSE Local 16 stagehand for a year in a dozen various capacities including camera op before Covid shut everything down in early March and on every job we all pitched in on the load in and load out of the usually hundreds of roadie cases, so I had lots of time while “pushing boxes” to think about practical inventions that would improve the experience and reduce carpal tunnel injuries. For Elton John’s final tour concert at Chase Center and other gigs when I occasionally worked there I soon often volunteered to be assigned as a “loader” to help load or unload the 23 or so 18 wheelers that came in rather that risk injury or insult setting up their custom road show lighting, video walls, or stage, working under in the arena under the Local 16 boastful French Canadian head “carpenter” who was allowed to be a complete A%$#@ all while people incurred serious blood dripping on the floor injuries and several near misses from falling lights or running over by out of control roadie cases, but I digress. Roadie cases don’t have handles for steering so you can only really steer them by being at the smart caster end. If they had good, ergonomic, steering handles and didn’t have wheelbases up to 8 feet long or longer, i.e. were “vertical” carts like yours, we could have steered them from either end. The hybrid cart design I will be releasing soon has amazing ergonomic handles at the (usually) large fixed wheel end and is easily turned on a dime when loaded with hundreds of pounds so that is not the issue. I believe the type and positioning of the handles is just as important as the types of wheel for safe maneuverability and control, maybe more so, and should be comfortable whether you are pushing both handles or pushing one while pulling the other to execute a change of direction or using them to tilt the cart back onto the large rear wheels to negotiate over a curb, a few steps, or other obstacles going forward or back. Caster companies even fund research at universities where they have sophisticated sensors connected to computers to measure stress exerted on humans pushing carts in various ways but little consideration has been given to the ergonomics of handles in this industry based on what is currently on the market no matter whether you spend $800 or $8000. Vertical carts usually have the handles at the larger stationary wheel end and perhaps better, more ergonomic handles would be the simplest solution to your problem. I do agree with those who said more than half the weight will be on your swivel wheels as configured but my configuration puts an even larger percentage of the weight on my front casters but I have no problems steering from the start. Also yours seem of a diameter and width that would also increase the ground contact surface area and assumably the friction making them difficult to get going in any new direction you wish to start out in or change to. On the other hand the larger the surface area the smaller the force per square inch thus reducing the friction. Also those wheels all look pretty old so I wonder if you checked to see if the swivel ones are functioning properly.

 

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19 hours ago, saadasound said:

Doesn’t look ”top heavy”. Front casters are just too close to each other.

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