Single fixed pulley (power equals weight) — dimension sheet
Source: Xem Studio, https://xemstudio.com/objects/single-fixed-pulley-mechanism/  (sheet CC BY 4.0; files Xem Studio Design License, https://xemstudio.com/license/)
Basis: Xem Studio design following Brown No. 12 (1868)
Catalog version: 2026-10-20

Sizes: see table below
- A rope over a fixed pulley only changes the direction of the pull: in equilibrium the power equals the weight (P = W), and the hand moves as far as the weight.
- Here a pitch-Ø30 sheave in a block hung from the beam, a Ø40 × 40 weight (395 g in steel) on one end of a Ø3 rope, the other end free for the hand.
- Brown's No. 12.
- Parts (each has its own page): tackle-beam-240-sockets, tackle-block-15-top-stem, rope-sheave-3mm-pitch-30, ropes-3mm-single-fixed-pulley, tackle-weight-d40x40-socket, dowel-pins-metric.
- Brown's movement No. 12 (1868) shows it; this model is a Xem Studio design following his figure, every part at true size.

parameter  value
sheave  pitch Ø30 (Ø3 rope)
mechanical advantage  1
hand travel / weight travel  1

Files elsewhere (not hosted by Xem Studio; license as stated by the publisher):
- Henry T. Brown (1868, public domain): Five Hundred and Seven Mechanical Movements — scan on archive.org — web — Publisher's page; dimensions are facts — https://archive.org/details/fivehundredseven00browiala
- 507movements.com: Brown's movement No. 12: figure, his text and an animation — web — Publisher's page; dimensions are facts — https://507movements.com/mm_012.html

Free files (Xem Studio Design License, Xem Studio; STEP + STL, 1 parts): https://xemstudio.com/files/hardware/single-fixed-pulley-mechanism/index.json
API: https://xemstudio.com/api/geometry?object=single-fixed-pulley-mechanism