Lifting tongs: load-tightened scissor grip — dimension sheet
Source: Xem Studio, https://xemstudio.com/objects/lifting-tongs-mechanism/  (sheet CC BY 4.0; files Xem Studio Design License, https://xemstudio.com/license/)
Basis: Xem Studio design following Brown No. 494 (1868)
Catalog version: 2026-10-20

Sizes: see table below
- Two arms crossed on a pivot, their upper ends drawn together by two equal links meeting at a shackle: the hoist pulls the shackle up, the links pull the arm tops inwards, and the feet below the pivot close on the load. The grip is proportional to the pull, so the heavier the load the tighter it is held.
- Drawn gripping a 40 mm block: arms crossed at ±22.02°, link holes 60 mm above and feet 80 mm below the pivot, 40 mm links to the shackle pin 88.69 mm above the pivot.
- Brown's No. 494 (lifting tongs with a shackle and links); ice tongs, log tongs and crane grabs.
- Parts (each has its own page): lifting-tong-arm-140-foot, tongs-shackle-link-50, load-block-40, four-bar-links, dowel-pins-metric.
- Brown's movement No. 494 (1868) shows it; this model is a Xem Studio design following his figure, every part at true size.

parameter  value
arms  2, crossed, 60 / 80 mm
links  2 × 40 mm
load drawn  40 mm block
arm angle  ±22.02°

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. 494: figure, his text and an animation — web — Publisher's page; dimensions are facts — https://507movements.com/mm_494.html

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