In underground mining, development moved from chain to wire rope. Until the mid-1940s, the coal plow was dragged by a wire rope in the coal face. With the development of the Löbbe planer in 1947, the round link chain replaced the wire rope previously used in underground planing operations (planing chain). The geometric structure and technical requirements of the brush chain are described in DIN 22252. The dimensions range from ⌀ 26 mm to ⌀ 42 mm. Consequently, the breaking forces are 850 to 220 kN. Special materials (HO=Highly Optimized) have increased these values ​​to 960-2520 kN.

In addition to the use of the plow chain in underground mining, the so-called conveyor chain is also used. The conveyor chains are mounted with scrapers. This conveyor is used to transport the mined coal. These chains are defined in DIN 22252 and DIN 22255 for flat head chains. In recent years, chain manufacturers have continued to develop the geometric design of the classic conveyor chain. One of these results is known as class F chain and is used in the range up to ⌀ 60 mm on double center chain conveyors. The objective of these new developments is to increase coal extraction performance.

To build endless planer/conveyor chains of these dimensions, special connection locks are required. Here a distinction is made between flat locks according to DIN 22258-1 and block locks according to DIN 22258-2. Flat lock is used in planer chain, while block lock is mainly used in conveyor chains. The flat lock can pass both horizontally and vertically through the sprocket. The block lock can only pass vertically through the sprocket.

The symbolism of chains is varied and even opposite. With them, some grieve for their slavery and their misfortune, while others are proud of their prosapia and their power.

The Romans present us with proof of this antithesis: their emperors decorated with chains the soldiers who had distinguished themselves in war for their exploits and bravery, while at the same time they imposed them on the enemies they took prisoners as a sign of captivity and humiliation. Similar examples could be cited from other peoples and other times. The chains that have often been applied to the imprisoned, the captive, the slave, the insolvent debtor were frequently the distinctive character of kings, vassal lords, nobles and people constituted in dignity. Among the Gauls "Gauls (people)") was considered one of the main attributes of those who exercised power and among the English the chain represented the dignity of the lord-corridor of London, both during his duties and as a reminder of having performed them.

And in Spain, we can observe the opposite ideas symbolized in the chain. The weapons of one of the most powerful and flourishing kingdoms of ancient Christian Spain represent crossed gold chains in a field of gules or blood and in their center an emerald. They originate from the celebrated battle of Las Navas de Tolosa won against the Moors at the beginning of the century. In it, King Don Sancho of Navarra was the one who broke the chains of the palenque in which the Miramamolin became strong and then adopted that coat of arms for his monarchy. Other nobles, having distinguished themselves in this same feat of arms, also chose the same symbol to perpetuate their glory, such as the Mendozas, Peraltas, Estúñigas and others.

If on this occasion the chain was taken as a bell of honor, in other times in history it had to be used to punish rebellions or to prevent those that were feared in the future. It is known that once the resistance of the Catalans to recognizing Philip V as king was overcome, there was a certain order that knives could not be used but blunted and hanging from the tables or walls by means of a chain. Some private houses that the king had honored with his presence displayed chains on their main doors as if to imply that that place marked by the royal plant was closed to anyone else, no doubt alluding to the fact that in ancient palace etiquette, the doors and locks were called chain, from which comes the job of chain doorkeepers. These signs disappeared with the fall of the absolute regime, being judged incompatible with the one that was inaugurated.[4]​.

Some figurative meanings of chain are worth knowing:

In ships, chains are associated with anchors.

Royal Navy officer Samuel Brown (1776-1852) innovated on the HMS Penelope in 1806 by replacing the ships' cables with iron chains. The company he later founded supplied all the chains of the Royal Navy until 1916 and manufactured the chains of Isambard Kingdom Brunel's SS Great Eastern, of which the photographer Robert Howlett left evidence. This application of iron gave rise to a large amount of research and experiments in England on the strength and tensile of iron and on its various qualities. The soft iron used to make ship cables stretches under an effort of eighteen to twenty kilograms. Its soft, filamentous and above all homogeneous nature allows it to continue stretching uniformly for a fifth of its length before breaking.

Already in 1595, representations of a bridge with a deck suspended by chains, whose design is closer to a cable-stayed bridge, appear in the Machinae Novae (Venice, 1595) by Fausto Veranzio.[5] History records, however, that it was in the United States where the modern suspension bridge was born. A judge, James Finley&action=edit&redlink=1 "James Finley (engineer) (not yet drafted)") (1756-1828), had the idea of ​​a suspension bridge with wrought iron chains (1801).

Brown registered a patent for the manufacture of chains in 1816 and patented wrought iron links for a suspension bridge in 1817. That same year, others built Dryburgh Abbey Bridge, Britain's first chain bridge (1817). Brown had already experimented with a chain suspension bridge, building a trial structure with a span in 1813, which met with the approval of John Rennie and Thomas Telford. Several unsuccessful attempts at Ponts des Invalides were made by Navier (1824) and then Vergès") (1829), until the notable achievements of Thomas Telford (Menai Suspension Bridge") in 1826).

The chains on the bridges were replaced by cables.

Chains are typically used at low speeds with heavy loads. Some common chain types and speeds are:.

There are chains designed for high speed operations, for example:.

In each of these high-speed operations, the chain must be carefully selected. It is important to consider not only strength and wear resistance, but also the type of lubrication required.

In underground mining, development moved from chain to wire rope. Until the mid-1940s, the coal plow was dragged by a wire rope in the coal face. With the development of the Löbbe planer in 1947, the round link chain replaced the wire rope previously used in underground planing operations (planing chain). The geometric structure and technical requirements of the brush chain are described in DIN 22252. The dimensions range from ⌀ 26 mm to ⌀ 42 mm. Consequently, the breaking forces are 850 to 220 kN. Special materials (HO=Highly Optimized) have increased these values ​​to 960-2520 kN.

In addition to the use of the plow chain in underground mining, the so-called conveyor chain is also used. The conveyor chains are mounted with scrapers. This conveyor is used to transport the mined coal. These chains are defined in DIN 22252 and DIN 22255 for flat head chains. In recent years, chain manufacturers have continued to develop the geometric design of the classic conveyor chain. One of these results is known as class F chain and is used in the range up to ⌀ 60 mm on double center chain conveyors. The objective of these new developments is to increase coal extraction performance.

To build endless planer/conveyor chains of these dimensions, special connection locks are required. Here a distinction is made between flat locks according to DIN 22258-1 and block locks according to DIN 22258-2. Flat lock is used in planer chain, while block lock is mainly used in conveyor chains. The flat lock can pass both horizontally and vertically through the sprocket. The block lock can only pass vertically through the sprocket.

The symbolism of chains is varied and even opposite. With them, some grieve for their slavery and their misfortune, while others are proud of their prosapia and their power.

The Romans present us with proof of this antithesis: their emperors decorated with chains the soldiers who had distinguished themselves in war for their exploits and bravery, while at the same time they imposed them on the enemies they took prisoners as a sign of captivity and humiliation. Similar examples could be cited from other peoples and other times. The chains that have often been applied to the imprisoned, the captive, the slave, the insolvent debtor were frequently the distinctive character of kings, vassal lords, nobles and people constituted in dignity. Among the Gauls "Gauls (people)") was considered one of the main attributes of those who exercised power and among the English the chain represented the dignity of the lord-corridor of London, both during his duties and as a reminder of having performed them.

And in Spain, we can observe the opposite ideas symbolized in the chain. The weapons of one of the most powerful and flourishing kingdoms of ancient Christian Spain represent crossed gold chains in a field of gules or blood and in their center an emerald. They originate from the celebrated battle of Las Navas de Tolosa won against the Moors at the beginning of the century. In it, King Don Sancho of Navarra was the one who broke the chains of the palenque in which the Miramamolin became strong and then adopted that coat of arms for his monarchy. Other nobles, having distinguished themselves in this same feat of arms, also chose the same symbol to perpetuate their glory, such as the Mendozas, Peraltas, Estúñigas and others.

If on this occasion the chain was taken as a bell of honor, in other times in history it had to be used to punish rebellions or to prevent those that were feared in the future. It is known that once the resistance of the Catalans to recognizing Philip V as king was overcome, there was a certain order that knives could not be used but blunted and hanging from the tables or walls by means of a chain. Some private houses that the king had honored with his presence displayed chains on their main doors as if to imply that that place marked by the royal plant was closed to anyone else, no doubt alluding to the fact that in ancient palace etiquette, the doors and locks were called chain, from which comes the job of chain doorkeepers. These signs disappeared with the fall of the absolute regime, being judged incompatible with the one that was inaugurated.[4]​.

Some figurative meanings of chain are worth knowing:

In ships, chains are associated with anchors.

Royal Navy officer Samuel Brown (1776-1852) innovated on the HMS Penelope in 1806 by replacing the ships' cables with iron chains. The company he later founded supplied all the chains of the Royal Navy until 1916 and manufactured the chains of Isambard Kingdom Brunel's SS Great Eastern, of which the photographer Robert Howlett left evidence. This application of iron gave rise to a large amount of research and experiments in England on the strength and tensile of iron and on its various qualities. The soft iron used to make ship cables stretches under an effort of eighteen to twenty kilograms. Its soft, filamentous and above all homogeneous nature allows it to continue stretching uniformly for a fifth of its length before breaking.

Already in 1595, representations of a bridge with a deck suspended by chains, whose design is closer to a cable-stayed bridge, appear in the Machinae Novae (Venice, 1595) by Fausto Veranzio.[5] History records, however, that it was in the United States where the modern suspension bridge was born. A judge, James Finley&action=edit&redlink=1 "James Finley (engineer) (not yet drafted)") (1756-1828), had the idea of ​​a suspension bridge with wrought iron chains (1801).

Brown registered a patent for the manufacture of chains in 1816 and patented wrought iron links for a suspension bridge in 1817. That same year, others built Dryburgh Abbey Bridge, Britain's first chain bridge (1817). Brown had already experimented with a chain suspension bridge, building a trial structure with a span in 1813, which met with the approval of John Rennie and Thomas Telford. Several unsuccessful attempts at Ponts des Invalides were made by Navier (1824) and then Vergès") (1829), until the notable achievements of Thomas Telford (Menai Suspension Bridge") in 1826).

The chains on the bridges were replaced by cables.

Chains are typically used at low speeds with heavy loads. Some common chain types and speeds are:.

There are chains designed for high speed operations, for example:.

In each of these high-speed operations, the chain must be carefully selected. It is important to consider not only strength and wear resistance, but also the type of lubrication required.