Many industries use floor scales. To some, a floor scale is just a piece of metal with some weight sensors under it that determines weight. To others, the floor scale is a key component in the production of a quality product. What makes one floor scale better than another is the type of load cell and the suspension used to apply force to that load cell to determine weight.
There are six types of floor scale suspension systems listed in the order of scale performance, repeatability and accuracy with the best result:
Mechanical Lever
Threaded Foot
Ball in Cup Threaded Foot
Rocker Pin Foot
Framed Rocker Pin
Electromagnetic Force Compensation Load cell
The type of suspension of the floor scale ties into how the weight is applied to the measuring element of the scale. Let's briefly take at each type.
Mechanical Lever:
This is the oldest type of scale and some are still in service today.
The load is applied to the deck or platter of the scale and a series of levers ‘ratio’s’ down the load applied.
For example, a mechanical scale could have a 100/1 ratio. That means that a 1000 lb load would apply 10 lbs of force to the mechanical beam or dial used to display the weight.
These are entirely mechanical and require many troubleshooting step if they do not pass a calibration or performance test.
They have many moving parts that can impact the weight and no alarms or ability to notify the operator that something is wrong.
Most suitable for shipping/ receiving where small errors are not an impact on product quality.
Robust but very difficult to service and repair as parts are no longer available.
Up to 10,000 display divisions.
Threaded Foot:
Most common type of floor scale today.
Available from many manufacturers all over the world.
Typically the type of floor scale you will see for sale on the internet.
The threaded foot is rigidly attached to the load cell with no play between the deck and foot.
They are susceptible to side forces and are easily damaged by side loading (fork truck dropping and dragging a load across the scale).
Work well for shopping and receiving where small errors are not an impact on quality.
There are not many accessories available to protect your scale.
These types of scale are economical.
Some compatible parts are available when service is needed unless it's an off brand from overseas.
Some consider these types of scale disposable due to cost of repair when needed.
No more than 5000 displayed divisions.
Ball in Cup Threaded Foot
This is a step up from the straight threaded foot scale.
There is a ball encapsulated inside the foot that allows some movement of the deck when loading and unloading.
The movement of the deck absorbs some side loading but can be damaged if it's excessive.
Scale calibration holds longer on these types of scales when compared to a threaded foot type.
Works well for shipping and receiving you should consider adding some scale protection devices around the scale such guards and locator plates.
Your scale representative can help with making sure your scale stays protected when using this type of scale for counting and other plant processes.
Can be set-up at 10,000 displayed divisions (5000 divisions for Legal for Trade Weighing)
Link: https://www.b-tek.com/clydesdale-24-x-24-2-500-lb-stainless-911-3100
Rocker Pin Foot:
A rocket pin foot does not threaded into the load cell. It uses a pin with an O-ring that locks into the load cell with a foot attached at the bottom.
The rocker pin allows for side loading and protects the cell.
Excessive side loading will pop the pin out of the cell and prevent damage in most cases.
Damaged suspension components are easily replaced since they are not threaded into the cell.
Suitable for shipping and receiving, piece counting, some batching and formulation.
These are only slightly higher in cost than a Ball in Cup type.
If using it for more than shipping and receiving you should consider adding some scale protection devices around the scale such as guards and locator plates.
Your scale representative can help with making sure your scale stays protected when using this type of scale for counting and other plant processes.
Can be set-up at 10,000 displayed divisions (5000 divisions for Legal for Trade Weighing)
Framed Rocker Pin Suspension
Superior analog or digital scale design above all others.
The rocker pin frame design uses a rocker pin with O-ring on each and end between a framework anchored to the floor with a tooled receiver cup and receiver pocket in the load cell.
The framework holds the scale deck from moving too far on the rocker pin to pop it out or damage the scale when side loaded.
Excessive side loading will push the scale deck against the framework limiting it's motion and protecting the cell.
These scales are easily maintained and last a very long time.
The rocker pin suspension returns the scale to a perfect setting point each time making them superior at retaining zero, calibration and expected performance.
These types of scales are typically priced between 30% and 40% higher than a footed scale and last at least 5 times as long.
There are many accessories for this type of scale from ramps, portability frames, indicator mounting columns and custom fixture and sizes.
Your scale representative can help with making sure your scale stays protected based on the unique environment it will be installed in.
This scale meets criteria for Lean Manufacturing when weighing performance is critical to the quality of the finished product.
Can be set-up at 10,000 displayed divisions (5000 divisions for Legal for Trade Weighing)
When using a digital load cell in this design of scale, the scale can perform at 50,000 displayed divisions.
Link: https://www.b-tek.com/b-tek-scales-floor-scales/rps-floor-scale-rockerpin-group
Electromagnetic Force Compensation Load cell (with Mechanical Flexure System)
This type of scale uses a combination of a mechanical lever and a flexure system.
The deck only moves in a vertical direction due to the flexures, this applies load to the single electro-mechanical force compensation load cell.
Like the mechanical scale, there is a ratio used to bring the load applied to the load cell down. The flextures keep the load from becoming off centered on the cell and provide unsurpassed scale resolution, repeatability and accuracy.
These scales are considered industrial weighing devices but use a load cell very similar to what is used in a lab balance. Because of this, excessive side loading and abuse will damage the device.
Industries that use this type of scale require very precise weight modules and typically have protocols in place for operators to protect the scale when it's being used.
These scales requires a trained service technician to maintain, calibrate and repair.
These scales can be three times more than a framed rocker pin scale due to performance and last a very long time when taken care of.
There are many accessories for this type of scale from ramps, portability frames, indicator mounting columns and custom fixturing and sizes.
Your scale representative can help with making sure your scale stays protected based on the unique environment it will be installed in.
This scale meets criteria for Lean Manufacturing when weighing performance is critical to the quality of the finished product and has documented performance standards to back it up.
Can be set up with 600,000 displayed divisions with documented performance specifications. They are not typically used in legal for trade applications because they outperform the required NTEP standards.
Hopefully this information helps you determine what type of scale is suitable for your weighing application and would gladly make a visit to your facility to put together a specification. We also can provide e-demos outline product features and performance specifications on any type of floor scale you are considering. You can reach our sales representatives here: https://www.cech.com/sales-representatives
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