#rigging

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

Capstan and belt-friction maths (the Euler-Eytelwein equation) as an API, computed locally and deterministically. The capstan endpoint applies T1/T2 = e^(μ·β) — the ratio of the tight-side to the slack-side tension of a rope or belt wrapped around a drum depends only on the friction coefficient and the wrap angle, not the drum diameter — and solves for whichever of the two tensions, the friction or the wrap angle you leave out, with the wrap angle given in degrees, radians or whole turns. The holding endpoint shows the capstan effect: how a small force holds or moves a large load, holding force = Load·e^(−μβ) and pulling force = Load·e^(+μβ) — a few turns of rope around a bollard lets one person hold a ship. The belt endpoint sizes a belt drive: from the maximum tight-side tension, the friction and the wrap angle it gives the slack-side tension, the effective (net) tension T1 − T2 that drives the load and, with the belt speed, the maximum power transmittable before the belt slips. Everything is computed locally and deterministically, so it is instant and private. Ideal for mechanical and marine-engineering tools, belt-drive, winch, hoist and band-brake design, climbing and rigging apps, and physics education. Pure local computation — no key, no third-party service, instant. Live, nothing stored. 3 endpoints. This is belt and rope friction; for belt length, wrap angle and speed ratio use a belt-drive API.

api.oanor.com/capstan-api

Rigging and lifting load maths as an API, computed locally and deterministically. The wll endpoint relates the working load limit to the minimum breaking strength through the safety (design) factor: give a breaking strength and it returns the working load limit (WLL = MBS ÷ safety factor), or give a working load limit and it returns the minimum breaking strength your hardware must be rated for (MBS = WLL × safety factor). The safety factor can be given directly or looked up by component — general rigging and wire rope 5, chain sling 4, shackle 6, personnel/man-rated 10. The sling endpoint computes the tension in each leg of a multi-leg sling as the lifting angle changes: because the legs pull at an angle, each carries more than its share, with a load factor of 1/sin(angle to horizontal) — 1.0 vertical, 1.15 at 60°, 1.41 at 45° and 2.0 at 30° — and it accepts the angle from horizontal, from vertical or the included angle between legs. The safety endpoint lists the typical design factors. Loads are given in kilograms, pounds, tonnes, kilonewtons or newtons and reported in all of them. Everything is computed locally and deterministically, so it is instant and private. A planning aid, not a substitute for a qualified rigger or the governing standard (ASME B30, EN, local code). Ideal for crane and lifting apps, construction and warehouse tools, theatrical and entertainment rigging, and towing and recovery calculators. Pure local computation — no key, no third-party service, instant. Live, nothing stored. 3 endpoints. This is rigging load maths; for the weight of the steel being lifted use a metal-weight API.

api.oanor.com/rigging-api