Ok, so what is Center of Gravity (CG) and why is it important? Technically, CG is a point from which the weight of a body or system may be considered to act. It’s the point at which weight is evenly dispersed and all sides are in balance.
This basically means that if you took the entire mass of an object and condensed into a single point, that point would have an X, Y, and Z location in space and at a weight equal to the total weight of the object, which is called the Center of Gravity. This CG point is important plan and know how your King’sCart will perform when loaded and how much work it may require you to be able to rotate your workpiece along its axis.
In short, if you require your King’sCart to tilt or rotate in order to deliver a workpiece, you want to be it rotate as effortless as possible. This not only reduces the effort and muscle required to rotate but reduces the stress on key components of the King’s Cart . Determining the CG also will help you determine if you will require using your outriggers for additional stability to prevent the King’sCart from becoming unstable or tipping over.
Your Goal?: To position the Loaded Gantry Span of your King’sCart to be as close to the rotational axis point (center of rotation) of the cart.
So, how do you calculate the CG for the workpiece you’re transporting? There’s no real simple universal answer, well…there IS an equation. If you’re transporting a flat solid slab of Marble, for example the CG for the load will be in the center of your slab, in all 3 directions. That means the center of gravity would be at the midway point of the overall Length, Width, and Thickness of the slab. Fairly simple.
But let’s take that same slab and add cutout for a kitchen sink:
Above, you can see how the Center of Gravity(CG) shifts up and the left as the majority of the mass has shifted because of the removal of material.
What does this new CG point mean? This means if you want to make rotating your workpiece load as effortless as possible, just be sure the rotational axis of the cart crosses over this point when you have the Gantry Span clamped in place!
Taking into account obstacles or site obstructions, you can situate the Gantry Span at a location that best suites your delivery requirements. As long as you’re not restricted by site conditions, you can orientate the Gantry across the CG at any position and still have the ability to rotate the load with very little effort or strain to the King’s Cart and crew. As example options
Now let’s take a look at the CG in the Z-axis or the thickness of the material. Typically, when the workpiece is a uniform material density, the CG will be directly in the middle . Below is an example Cross-Section of a Solid workpiece versus a Cross – Section with Profile Edges to show how the CG is affected :
Looking at the diagram above, you can see that slab with the profiled edge has a CG that is now closer to the top surface because much of the mass is above the centerline of the slab. Knowing the proximity of where the CG is in the Z-axis, will help you to adjust the King’sCart Pivot Slide.
The Pivot Slide provides up/down with 3” of adjustment, Or the Pivot Slide can be fully removed if necessary, providing a wide range of CG adjustment options!
When the workload is clamped in place, any cross braces, clamps, and the Gantry Span itself add to the overall mass and will shift the CG for the system to be “higher” above your Workload. Because the amount of hardware and length of the Gantry Span varies, the full system will need to be evaluated to best predict where the CG is for the system the slide bracket can be adjusted as necessary. The Axis Pivot point and the CG of the system do not need to be in alignment, but the closer they are together, the easier it will be to manually rotate the workload.
This overview should give you and idea of how to plan to mount your work-piece in preparation for transportation and delivery, but, other variable conditions may dictate the actual mounting location/positioning of your workload.
We know every job comes with its own set of variables, we just tried to make it as versatile as convenient for the work crew as possible! Understanding how your King’sCart was designed is just another way to understand how to put this tool to work for you, not the other way around!