Over 180 years, calipers are the most common professional measuring tool at every production facility.
Calipers are distinguished from rulers and measuring rulers by the presence of indicating devices, measuring jaws and movable frames.
Calipers have unique potential among another linear meter:
- “Colombics” measure four parameters of the tool (external and internal dimensions, depth and
- Precision calipers in the range of 0 ... 150 mm at the same time replace 6 micrometers;
- The extended calipers measure sizes up to 10000 mm with jaws up to 1000 mm.

                                                 Pict.1 Han Bronze Vernier Caliper [2]
Old calipers were used in China about 1100 ... 3400 years ago, as a kind of measuring ruler with a movable frame and two jaws / 1,2 /, see Pict 1. Old Calipers did not have special indicating devices, due to which their error (with transverse measuring jaws) exceeded the error of conventional measuring rulers..

                   Calipers are classified by type of indicating devices [3], Pict. 2-5:

Pict. 2 Bar nonius (with Vernier scale)                Pict.3 With integrated dial (indicator)
Pict.4 Digital electronic (with incremental or           Рict.5 Computerized (with integrated
             photoelectronic scale)                                                   microcomputer)


      Caliper models are known that have not become an independent common gauge due to
structural and metrological deficiencies, among which the following calipers are most interesting:

    Pict.6 With a diagonal scale [4]                                    Pict.7 With moire scale [5]
   Patent H.Packet 1,231,934 1917 г.                     Patent G.E.Giambiasi 1,415,627 1922г.

     Pict.8 With a micrometer head on                          Pict.9 With indicator on a movable 
                a movable sponge [6]                                                      frame [7]                        

    Patent H.Packet 1,231,934 1917 г.                         Patent L.H.Dowe 2,447,612 1948г.                                   

                                             Pict.10 Digital mechanical calipers with                
                                                                ring decades [8]                                                      

                                                 Patent F.M.Gamroth 2,034,804 1936 г.                    
                                               Pict.11 Double indicator caliper SHCK
                                                          London meter [8]

                                           Four main types of indicating devices 
                                   (Vernier, dial, digital, computerized) correspond 
                              to the four main generations of the 180-year evolution 
                              of the calipers, we have established a highly significant 
                               correlation in time with the four Industrial revolutions
                                   (from «1.0 Industry» to «Industry 4.0»). Pict. 12.

                         Pict.12 Correlation of caliper generations with Industrial Revolutions

The first type of indicating devices for calipers was the vernier reading in calipers, which
corresponds to the time of the First Industrial Revolution «In-dustry 4.0» (the emergence of steam
engines and mechanical production) in the period of 1760 ... 1840th [10].
Vernier calipers use the Vernier indicating principle, which
was discovered two centuries earlier.

                                                    Pict.13 First nonius caliper


The first vernier caliper appeared in France in 1837 ... 1840
at the royal factory, while the first caliper had a measuring
range of 0 ... 530 mm, a division price of 0.100 mm and
an error of 0.250 mm [1], Pict.13.
Error of Vernier calipers an order of
magnitude smaller errors in measuring tapes and rulers,
however, could not be better 0,030 mm [3].

                                                     Pict. 14 Nonuis caliper
                                     Photo Of The «Museum. Tool «MICROTECH»

Vernier calipers are widely used for over 180 years and
have good perspectives in reliability and availability. Pict.14.
70 years after the appearance of Vernier calipers
appeared calipers dial, it coincided with the
Second industrial revolution «Industry 2.0»
(the advent of electricity and mass production in the late
19th century to early 20th century [10]).  

                                           Pict.15 Indicator caliper Mauser
The use of analog calipers is hampered by the need for
high intensity, high skill and absolute view of the users
to ensure the passport indicators analog calipers.
These disadvantages are absent from the calipers
with a digital readout, the appearance of which
coincided with the Third industrial revolution «Industry 3.0»
(digital and computer) in the period from 1960 to 2011.
Calipers with digital indication developed
and patented almost simultaneously Hans Ulrich Mayer
(the first President of the Swiss «Sylvac» in 1972 /11/) and Ingvar Andermo (a renowned expert of the Swedish Royal Institute /12/, which in the future are quite productive in the American division of the Japanese company Mitutoyo /13/).     
The first production models of digital electronic calipers has released a Swiss firm Tesa /1/,
see Pict.16. These calipers was a glass scale and a photoelectric reading device which, after the
incremental scales have ceased to apply in the calipers.

                 Pict.16 Digital caliper TESA Photo of the «Museum. Tool «MICROTECH»
                                              Digital electronic calipers modern
                                                 Incremental scales developed
                                                and began to produce in 1980,
                                            the Swiss firm «Sylvac» [1], Pict. 17

                                     Pict.17 Photo of the old type Sylvac caliper


The measuring world largest Japanese firm Mitutoyo in the early 80-ies of the purchased
licenses, and successfully used the technology to other developers [1]:
In 1981 had a common range and a common catalog by the innovative Swiss
firm «Sylvac» [13];
- In 1983, it acquired a license and technology for the production of incremental caliper
scales from the Royal Swedish Institute [1];
In August 1984, it was able to produce and sell 100 thousand digital calipers[1].
Japanese specialists of the company «Mitutoyo» in 1983 patented wired digital calipers with external PC [15], watch pict.18.

                                Pict.18 Caliper Mitutoyo with data transfering cabel


In 1987, another Japanese firm «Man Design» patented side transmitter for digital electronic Vernier caliper [16]. In 37 years, there have been virtually no changes in design or functionality
The appearance of calipers with computer reporting devices in 2015 coincided with the Fourth Industrial Revolution «Industry 4.0» (synthesis of digital, physical and biological technologies), which was announced at the Hannover Fair in 2011 by Klaus Schwab [10].
Calipers the previous three levels had many differences from the system of «Industry 4.0», in contrast to the calipers accounting-computer devices «Caliper 4.0».

                                      Pict.19 Patent US 10184772 Computerized
                                                               caliper [17]


The caliper «Caliper 4.0» for use in «Industry 4.0» have the following functions:
- A two-way exchange of information of the caliper «Caliper 4.0» with all composite systems «Industry 4.0» («Factory 4.0», «Machine 4.0», «4.0 Metrology», servers, PCs, and smart backgrounds, with different meritele 4.0);
- Operation of calipers «Caliper 4.0» in automatic mode (mathematical processing of measurement results, logging and archiving, current and adjusted communication with external component systems «Industry 4.0»)
- Adaptive condition monitoring of the caliper «Caliper 4.0» (compensation of temperature expansion of the measured part, mathematical compensation of error in the measuring range, self-calibration and calculation of misalignment, saving the results of the previous calibration, date of the subsequent calibration). 
-Innovative calipers «Caliper 4.0» with reporting-computer devices were the first in the world
to be patented by specialists of «MICROTECH» /17, 18/, since 2016 computer calipers (models «Tablet» and «Intelligent») are serially produced in Ukraine and exported to 45 countries.
                         Pict.20 Computerized caliper MICROTECH Tablet 4.0 [3]



1.DIN 862 «Caliper»                                      
2.Catalog «MICROTECH-2020» 56En
3. Pat.US№1231934 «Caliper»
4. Pat.US№1415627 «Precision instrument»
5. Pat.US№403726 «Micrometer gage»
6. Pat.US№2447612 «Dial indicator base»
7. Pat.US№2034804 «Caliper rule»
8. Scwab К. « The fourth industrial revolution».-2019 р  
9. Pat.CH№8600/80 «Capacitive length» .-1980
10.Pat.SE№7714010 «Measuring device» .-1977
11.Pat.US№7661840 «Absolute position…» .-1991
12.Comprehensive catalog «Mitutoyo-Sylvac». №13-17.-1982
13.Pat.US№4612656 «Digital indicator type…»
14.Pat.US№4930095 «Data transmitting apparatus…»
15.Pat.US№10184772 «Computerized caliper»
16.Pat. UA№128692 «Caliper «Intelligent Caliper»