#pulley

Pulley and block-and-tackle mechanics as an API, computed locally and deterministically. The advantage endpoint computes the mechanical advantage of a pulley system — the ideal MA equals the number of rope parts supporting the load, which is also the velocity ratio — and returns the effort needed to hold or raise a load, effort = load/(n·efficiency), the length of rope that must be pulled (n times the lift height) and the work in and out. The friction endpoint models a real block and tackle where every sheave loses a little tension: the mechanical advantage becomes MA = e·(1−eⁿ)/(1−e) for a per-sheave efficiency e (≈0.96 for a plain bearing, ≈0.98 for a ball bearing), so it returns the true MA, the overall efficiency and the extra effort friction costs you. The solve endpoint takes any two of the load, the effort and the number of rope parts and returns the third — for example, how many parts you need so a given person can raise a given load, or the heaviest load a winch can lift. Everything is computed locally and deterministically, so it is instant and private. Ideal for rigging, lifting and hoist-design tools, sailing, climbing and theatre-rigging apps, crane and winch sizing, and physics education. Pure local computation — no key, no third-party service, instant. Live, nothing stored. 3 endpoints. This is pulley and block-and-tackle mechanics; for lever and moment balance use a lever API and for rope-around-a-drum capstan friction use a capstan API.

api.oanor.com/pulley-api

Belt-drive and pulley maths as an API, computed locally and deterministically. The belt endpoint computes the length of an open V-belt or flat belt from the two pulley diameters and the centre distance with L = 2C + (π/2)(D1+D2) + (D1−D2)²/(4C), and returns the belt length plus the wrap (contact) angle on each pulley; pass a driver rpm and it also gives the belt surface speed. The ratio endpoint computes the speed ratio of a pulley pair (driven ÷ driver diameter, since N1·D1 = N2·D2): give a driver or driven rpm and it returns the other, the torque ratio and the belt speed. The centers endpoint reverses the length equation to find the centre distance for a target belt length, solving the equation numerically. Diameters and distances accept millimetres, centimetres, metres, inches or feet, and lengths are reported in several units. Everything is computed locally and deterministically, so it is instant and private. Ideal for machine and drivetrain design tools, maintenance and MRO apps, maker and CNC projects, and mechanical-engineering calculators. Pure local computation — no key, no third-party service, instant. Live, nothing stored. 3 endpoints. This is belt-and-pulley power transmission; for bicycle gear ratios and development use a bike-gear API and for bolt tightening torque use a torque API.

api.oanor.com/beltdrive-api