spring scales

 

Spring scales are weighting balances that need to be hung to make their measurements. They are made of a spring with a loop at the top end for fixing and a hook at the other end to hang what need to be weighted.

Spring Scale

pocket balance

The first record of a spring balance is found in Great Britain around 1770 near Wolverhampton. The inventor incorporated the company of George Salter & Co., who patented the spring balance in 1838.

A spring scale is are also called Spring Balance is very simple: it only uses gravity and Hookes law to operate.

However, it only measure mass (the force of gravity) and not weight and the reading may depend of where you are on the Earth surface. For that reason they are marked with a mention similar to: “no legal for trade”.

Because of their simplistic conception, competitive cost,  robustness, ease of use and rapidity, it is a very popular way to take quick measurements that don’t need to be 100% accurate, like babies weighting in developing countries up to silo storage loads in farms.

 

FEATURES OF THE COUNTING SCALE

Counting ScaleCounting balances not only measure the weight of the given material but furthermore calculate how much an individual good costs given that weight. Counting scales can be manually set up by the shop owner so that the charge for 1 kg can be changed at any time. The whole method described above (weighing and counting) can be completed very fast, which in turn makes shopping more agreeable for both shop owners and purchasers. Anyhow, recently more advanced counting scales have been popularized…
More advanced calculating scales which are employed only in supermarkets or hypermarkets are equipped with a printer enabling purchasers to actually do the weighing themselves. What the consumer does is that he/she takes the desired number of fruit or vegetables, puts them on the scale and presses the button which has a drawing of the particular fruit or vegetable on it. When the scale has done the counting, it prints a special label with glue on it which can be easily attached to the product. Such an operation saves a lot of time for the cashier who does not need to weigh the articles. Clients usually also appreciate it when their time spent by the cash register is as short as possible.

ELECTRONIC WEIGHTS

scalesIn the course of the centuries the most recognizable category of weights used were ‘traditional’ beam balances. The introduction of electricity reformed the weighing industry. Since the 19th century many new types of weights (based on electricity) have come into view. Some of the examples of electricity-powered balances used nowadays are:

Industrial Scales
As the name suggests, they are most frequently encountered in numerous industries (transport, trade and agriculture, warehouses etc.) where they are used to weight objects up to several hundred tones. Resistance to decay, extreme temperatures, humidity and acid makes them the most damage proof scales in the world.

Personal scales
Recent technological inventions have enabled us to measure not only the weight of a person but also their BMI (Body Mass Index) as well as the percent of the body fat. Maximum load found in most personal balances ranges around 150 KG.

Car scales
Usually settled on the ground, they are used to weigh the front axle load. The driver steers the car which runs on the scale.

Precision Scales
Most frequently used in medical and jewelry businesses, they are used to assess the weight of extremely small, sometimes microscopic-like, objects with accuracy up to 1 nanogram. Only electronic weights can reach that level of precision.

Kitchen scales
Those who like to cook and follow different recipes use kitchen scales to measure the weight of e.g. flour or grits.

WEIGHING SCALES STORY

Scales HistoryThe earliest evidence of the use of balances can be traced to 2400-1800 B.C. There are also many convincing traces which suggest that weighing system was broadly used by the Egyptian civilization. The first recorded form of a weighing device other than the balance occurred in 400 B.C. and was known as the Bismar.

Its construction included a rod of wood with a large weight fixed at one end. The Romans invented the steelyard in 200 B.C.Originally known as the statera, the English word steelyard comes from the German Stalhof, the name of the London base of the Hanseatic merchants of the Middle Ages, who used the instrument extensively in their businesses. A historical figure who designed the first self-indicating scale was Leonardo Da Vinci.

The next step in the evolution of the balance was the focus on the knife-edge as a pivot of the scale.Illes Personne de Roberval. Roberval discovered the Static Enigma, which was to defy explanation for the next hundred years. Machines to weigh large loads began to develop during the eighteenth century towards the end of the 19th century, the technology of weighing machines began to develop into the type of machines we would recognize today.

In 19th century inventors began to consider and implement the types of scales which would be programmed to estimate the value of goods. In the late 1940s mechanical weighing began to combine with electronics.

THE ANALYTICAL BALANCE

Analytical BalanceThe history of analytical lab balance dates back to 1945 when Mettler Toledo company founder Erhard Mettler introduced the first Single-pan analytical balance. Large-scale production of Toledo weights began in 1946. Nearly three decades later, in 1971, the first nanogram balance was introduced.

The first fully electronic precision balance,  PT1200 scale, appeared on the market in 1973. A new force restoration technology was introduced in 1989. It eliminated many hand assembly steps, assured manufacturing quality control and, ultimately, reduced cost. Soon after, in 1993, the new Mettler Toledo electronic microbalance with a 51 million point resolution was introduced.

The first ultra-microbalance with a weighing capacity appeared in 1996 and the first monolithic weigh cell technology was introduced in 1997. Himadzu Windows Direct communication function introduced many new useful mechanisms in lab scales such as:  record weight or computed values generated by the balances. The latest innovations include: adding a color touch screen, Bluetooth connectivity in 2005, 61 million digit resolution in 2009 by Mettler Toledo XP6U.