Trochlea

Latin-English

trŏchlĕ|a, -ae. (ˈtro.kle.a) fem.

1. A pulley block; a pulley.

[Greek τροχιλεία trochilēa.]

Cic.	100%	Class.	52%	Rom.	25%	Med.	0%	Neo.	0%

Constructions

Adjective constructions

• inferior trochlea — ‘the lower pulley block,’ Vitr. [γ³], [γ⁵], [γ¹¹], [γ¹²]; [γ⁴]

Noun constructions

• orbiculus trochleae — ‘the wheel of a pulley,’ Vitr. [γ³], [γ⁴]

Loci

Classical

• αʹ Lucretius, De Rerum Natura 4.905:

• γʹ⁻⁴ adj. adj.² n. n.² Vitruvius, De Architectura 10.2.1:

Alligatur in summo trochlea, quem etiam nonnulli rechamum dicunt. In trochleam induntur orbiculi 〈 duo 〉 per axiculos versationes habentes. Per orbiculum 〈 summum 〉 traicitur ductarius funis, deinde demittitur et traducitur circa orbiculum trochleae inferioris. Refertur autem ad orbiculum imum trochleae superioris et ita descendit ad inferiorem et in foramine eius religatur.

The pulley block, which some also call rechamus, is fastened at the top. Two pulley wheels are inserted into the block, turning on its axles. The tow rope is passed over the top wheel, then it is dropped down and passed around the lower block's wheel. It is then brought back to the bottom wheel of the upper block, and so comes down to the lower one and is fastened through the hole in it.

• γ⁵ adj. Vitruvius, De Architectura 10.2.3:

Cum vero in ima troclea duo orbiculi, in superiore tres versantur, id pentaspaston dicitur.

But it is called a pentaspaston when there are two sheaves turning in the bottom block and three in the upper one.

• γ⁶⁻⁹ Vitruvius, De Architectura 10.2.4:

Troclea in summo capite machinae rudenti contineatur, et ex eo funis perducitur ad palum et quae est in palo trocleam inligata. Circa eius orbiculum funis indatur et referatur ad eam trocleam, quae erit ad caput machinae religata. [...] Trocleae et ductarii funes, uti supra scriptum est, expediuntur.

The pulley block should be held in place at the top of the machine by a cable, and from it a rope led through to a stake and the block tied to the stake. The rope should be inserted around its sheave and brought back to the block fastened to the top of the machine. [...] The blocks and tow ropes are arranged as mentioned above.

• γ¹⁰–γ¹² adj. adj.² Vitruvius, De Architectura 10.2.6:

In his autem machinis trocleae non eodem sed alio modo comparantur. [...] Ita funis ductarius traicitur in inferioris trocleae foramen, uti aequalia duo capita sint funis, cum erit extensus, ibique secundum inferiorem trocleam resticula circumdata et contenta utraeque partes funis continentur, ut neque in dextram neque in sinistram partem possint prodire.

Now, in these machines the pulley blocks are not arranged in the same way, but differently. [...] So the tow rope is fed through an opening in the lower block, so that both ends of the rope are even when it is stretched out, and then both parts are held along the lower block by a cord wrapped around and tied so that they can't come out, either on the right side or the left.

Roman

• βʹ Cato the Elder, De Agri Cultura 3.5:

Trochileas Graecanicas binis funibus sparteis ducunt: orbiculis superioribus octonis, inferioribus senis citius duces.

Greek-style pulley blocks are operated with a pair of esparto ropes; you can pull faster with eight pulley wheels above and six below.