Scales are weight measurement tools and weigh machines. They are not to be confused with musical scales (minor scale, chromatic scale, pentatonic scale, universal scale, etc.). They are used throughout industrial, commercial and consumer products contexts.
Whether the goal is to determine weight based on a quantity or the quantity from a weight, industrial scales are used in a wide range of industries. Examples include: agriculture, healthcare, laboratory, transportation, food and beverage, consumer goods, pharmacy and more.
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The History of Scales
People have been using scales since they began trading goods with values counted by weight, such as gold. The oldest examples we have of weighing scales come from near modern-day Pakistan, in the Indus River Valley. Likely used between 2400 and 1800 BC, these scales consist of two plates attached to an overhead beam, attached to a pole in the middle. These were balancing scales, or balances. To use them, merchants would place an object of an established weight, such as a stone, in one, and the goods to be sold or purchased in the other. Usually, these stones were polished cubes with masses that shared a common denominator. They kept adding goods until the scales were equal. In addition to allowing for fair trade, these scales allowed people to begin banking.
Similarly, the ancient Egyptians began using scales by 1878 BC at the latest. Based on stones marked for mass, as well as the stories told by Egyptian hieroglyphs, the Egyptians seem to have had a well-established system of mass gold measurement. So, it’s likely that they had been using scales for some time before 1878 BC.
Meanwhile, in China, the earliest scale artifact comes from between the 3rd and 4th centuries BC. This too was a balance scale. It was made from wood and paired with bronze masses for measurement. It was discovered in a tomb near present-day Changsha, Hunan. By 400 BC, people around the world were creating different types of scales. Unfortunately, many of these scales were inaccurate and poorly made, giving merchants an opportunity to cheat their customers.
During the Italian Renaissance, scientists and polymaths like Leonardo da Vinci and Galileo (who was born about 100 years after da Vinci) studied elements of measurement and the scale. It was a lesser known Italian, though, who actually created a scale of sorts during this time. Santorio Santorio, a Venetian and a friend of Galileo, invented something he called a “weighing chair.” It was essentially a chair, placed on top of a balance platform suspended from the ceiling. When he sat on it, it would move to a greater or lesser degree, according to his weight. With it, he would track weight, both before and after eating and drinking.
Scales did not improve significantly until the late 1600s, when merchants and traders began using standardized weights. As they focused more on accuracy and standardization, they came up with new styles of scale. For example, in 1669, French mathematician Gilles Personne de Roberval created what became known as the Roberval balance. He showed and demonstrated his invention that year to the French Academy of Sciences. Its members were impressed because, unlike older balances, it did its job no matter where one placed weights in the pans.
In 1770, Richard Salter invented the spring scale. This was the first scale created that did not use a counterweight. Salter’s spring scale worked instead by measuring tension or pressure placed on a spring. It quickly became popular, eventually becoming an important tool in post offices. They still enjoy some popularity even today, because they are inexpensive to make and fairly trustworthy. Digital scales and electronic systems, though, are far more accurate.
In 1843, Sir Charles Wheatstone improved upon an earlier invention by Samuel Hunter Christie. This invention became known as the “Wheatstone bridge,” an electrical circuit that measures electrical resistance, or pressure. The Wheatstone bridge concept proved very important for a number of reasons. In the world of scales, it is linked to load cells, which are essential parts of all digital scales.
Fast forwarding nearly 100 years, in 1943, the bonded strain gauge, which is a component of the load cell, was first mass-developed. Then, in 1980, partners Edward Pryor and Richard Loshbough requested the first American patent for the digital scale.
Today, engineers continue to develop new scale types and technology. In 2014, for example, engineers introduced the idea of a hybrid scale called the “elastically deformable arm scale,” which works using a combination of beam balance and spring scale technology. It replaces the rigid arms of a traditional balance with flexible elastic rod arms. They work inside an inclined, frictionless sliding sleeve. The result is that the scale can support and weigh masses or loads at its edges while maintaining equilibrium. It can also weigh loads without using a counterweight.
Modern industrial scales are highly accurate, precise and versatile. As technology rapidly advances, we can expect them to become even better.
To make sure they are designing or selecting the proper mechanism for a given application, scale manufacturers must carefully consider many specific devices, features and options.
The most important variable in any industrial, commercial or consumer weighing operation is the maximum weight that a scale must measure accurately. Manufacturers can create scales that range in their weighing capacities from a matter of grams to upwards of 80,000 pounds. Another important variable manufacturers consider is whether the client wants accurate measurements down to the milligram, or they want measurements rounded to the nearest half pound. In addition, manufacturers must think about portability. For your convenience, manufacturers can create miniature scales or compact scales that you can move easily from one location to another. To learn about an individual manufacturer’s custom options, talk to them directly.
Scales use hydraulic, balance, springs, load cells or a combination to determine the weight of a given load.
Types of Scales
No matter the capacity or accuracy, nearly all scales are easily divided into two categories based on the implementation of the weighing device. Platform scales and hanging scales encompass virtually all other types of scales.
- Platform Scales
- Consist of a surface or scale pan upon which items and containers are placed. They calculate the static and dynamic load of objects or substances in a number of industrial, commercial and residential applications. Some, as is the case with balance scales, contain multiple platforms, while others, such as floor and bench scales, have only one. In any event, a system of levers, load cells or springs is arranged under the platform or pans to read the weight.
- Hanging Scales
- Suspend the load from a hook or chain. Sensors above the object to be weighed read the measurements. Crane scales are the most common example of a hanging scale (hang scale). However, hanging scales are increasingly available in small sizes, even pocket sizes (pocket scales), for such varied uses as weighing luggage at the airport or for fishing.
In addition to those mentioned above, there are countless scales available to customers.
- Animal Scales
- Sometimes called pet scales, are specifically created to weigh pets and livestock. Different scales are designed to weigh different animals; for example, scale makers have created a special apparatus for weighing eagles that keeps the eagle more relaxed and comfortable, and thus provides a more accurate weight-reading environment.
- Balance Scales
- Weight measurement tools that involve the use of a beam balanced on a fulcrum.
- Bench Scales
- Scales that are placed upon a bench, table or counter. Inherently smaller, these scales are used to weigh smaller objects or substances such as produce at a grocery store or pills in a pharmacy. In these settings it is not only the capacity of the scale that is of paramount value, but the accuracy. Bench scales are used in many industrial environments for a wide variety of application types, including shipping and receiving. While they are smaller, they are quite durable. This makes bench scales useful in weighing a wide variety of heavy objects.
- Counting Scales
- Used to count coins and currency in industries, such as retail and hospitality. Count scales often contain a memory component that stores the number and weight of various manufacturing parts.
- Crane Scales
- Hanging scales that measure the weight and tension of heavy, lifted objects and aid in the prevention of overload.
- Digital Scales
- Offer high precision by using complex weigh systems, such as load cell technology. Load cells translate the weight of an object into electronic signals, which are conveyed to the user in digital form.
- Electronic Scales
- Weigh scales that are electronically motorized and use electrical currents, charges and signals to accurately and precisely calculate the dynamic or static load of an object or substance.
- Filling Scales
- Measure liquids and gases in a variety of industrial applications. The size, shape and purpose of these scales range from large filling scales – used to measure bulk material, such as sand and gravel – to small gas cylinder filling scales used to measure gases like hydrogen and to create gaseous mixtures.
- Floor Scales
- General-purpose scales used in industry operations, such as in shipping and receiving. Floor scales are useful in weighing heavy objects such as drums and objects that require the use of equipment, like dollies or carts, for transportation.
- Industrial Scales
- Encompass a broad spectrum of weighing devices capable of measuring the weight of heavy loads with high accuracy for applications in which this measurement is relevant to commerce and safe business practice. As a scale capable of handling several tons of weight must inherently be large, they are not practical in some applications. Large scales such as these may themselves weigh several hundred pounds. Applications for these industrial scales include the weighing of freight, cargo, pallets and even the machinery itself.
- Kitchen Scales
- Used to help home cooks and commercial chefs weigh out the right amount of a product for their creation.
- Laboratory Scales
- Sensitive lab instruments often found in organizations in the medical and scientific communities. Lab scales can measure one-millionth of a gram and are capable of measuring small particles, such as dust or lint. They can also measure gaseous materials.
- Mechanical Scales
- Do not require a power source, and objects are either weighed by a balancing instrument, as in the case of beam scales, or by a mechanical lever or spring. The mechanical spring flattens as an object exerts pressure upon it, and the spring’s deformation, which depends upon the weight applied, determines the weight reading.
- Medical Scales
- Used to measure weight in hospitals, doctors’ offices and other medical settings.
- Portable Scales
- Can be moved from one place to another.
- Retail Scales
- Provide a convenient way for customers and employees to measure the portion size of various goods.
- Solar Scales
- Powered by energy from the sun. The sun’s power is converted into electricity through silicon semiconductors, called solar cells, and the cell’s absorption of light particles releases energy from the silicon.
- Truck Scales
- Heavy-duty scales used to measure vehicles like rigs or tankers. They usually measure to the nearest tonnage. Although the use of load cells remains a common weight-sensing technique for vehicles, truck scales also use bending-plate and piezoelectric weighing systems.
- Wall Scales
- Provide a convenient way to measure an assortment of objects ranging from grocery store items to animal carcasses.
Standards and Specifications for Scales
The specific style and system of individual weighing scales may vary considerably, but all commercially used and produced scales in the United States are subject to the standards established by the National Institute of Science and Technology to ensure the safety of workers and the accuracy of industries in which goods are sold by weight.
Things to Consider When Purchasing Scales
If you’re in the market for a reliable scale, you need to work with a reliable manufacturer, such as those we have listed on this page. Learn more about each of them by browsing their profiles or visiting their individual websites, the links to which you will find by scrolling towards the top of this page. To make sure you choose the right manufacturer for you, we recommend you take some time to write out your specifications and requirements. They will serve as a guide while you’re shopping around and help you ask the right questions of your potential scale supplier. Remember, the right manufacturer is not the one who can offer the lowest prices, but the one who can offer the best tailored experience for you.
- Analog Electronics
- The part of the scale that operates the measuring cell and circuits in an electronic system.
- The mechanism in a scale used to determine the weight of an object.
- The counting, weighing and preparation of industrial components.
- Bending-Plate System
- The method of weighing an object on metal plates by determining the amount of force applied to the plates.
- The process of testing a scale to ensure accurate weight readings.
- Calibration Error
- The amount of error between what an object’s weight on a scale appears to be and what the true mass of the object is.
- A device that monitors the weight of objects, as in a production line.
- Expresses the weight of an object in various formats, including dial, analog, digital and balance beam form.
- The change in a load cell’s output.
- Hysteresis Error
- The process of weighing an object many times but getting a different reading for it each time.
- A tool that uses the signal from a junction box to display the weight of an object in a readable format.
- A term for the number displayed that will vary randomly and sporadically rather than progressively.
- Junction Box
- A tool that uses the electronic signal from a load cell to determine the weight of an object.
- Light-Emitting Diodes (LED)
- Semiconductors that provide the display on digital scales and produce light through their reaction to electrical current. When electrical current is supplied in a particular manner, the diodes illuminate in numerical shapes.
- Liquid Crystal Display (LCD)
- The display provided on digital scales. LCDs block light through the reaction of liquid crystals to electric current; thus, the area in which the light is blocked is darkened, and when electrical current is strategically applied, the darkened areas form numbers, which represent the weight reading.
- The applied weight of an object to a load cell.
- Load Cell
- A mechanism that reflects the weight of an object in the form of an electronic signal.
- Load Cell System
- The use of load cells to measure an object.
- Load Pin
- A transducer used in determining the weight of an object.
- Measuring Cell
- The part of the scale that actually senses the weight and converts it into an electrical signal.
- The electronic signal produced when weight is applied to a load cell.
- Piezoelectric System
- The use of sensors to determine the weight of an object.
- A structure on which the weight of a heavy object is distributed in order to achieve an accurate weight reading of the object.
- A mechanism that rotates an object.
- The ability of a scale to produce the same reading for an object weighed multiple times.
- The smallest amount of weight that a scale can detect.
- Scale Pits
- Holes into which a scale is anchored.
- The change in a structure’s size after weight is applied to the structure.
- Strain Gauge
- A tool used to measure the change in size of a structure after weight has been applied to the structure.
- A tool that converts energy into a different form.
- A machine that consists of metal plates implanted into the ground. This is used to measure the weight of heavy objects, such as vehicles.
- The use of sensors to determine a vehicle’s weight while the vehicle is in motion. As the vehicle moves over the scale, the sensors establish the amount of force applied to each axle and calculate the total force applied.
- Weight Module
- An instrument that converts an item, such as a container, into a scale by measuring the capacity of the container.
- The amount of gravity exerted upon an object.