Trip hammer: wiper cam pressing the tail of a first-order helve — dimension sheet
Source: Xem Studio, https://xemstudio.com/objects/trip-hammer-mechanism/  (sheet CC BY 4.0; files Xem Studio Design License, https://xemstudio.com/license/)
Basis: Xem Studio design following Brown No. 353 (1868)
Catalog version: 2026-10-20

Sizes: see table below
- A shaft carrying wiper cams turns above the tail of the hammer helve: each lobe presses the tail down, the head at the other end of the lever rises, and when the lobe slips off the tail the head falls on the anvil. Two lobes give two blows per turn.
- First-order lever (fulcrum between cam and head): tail 80 mm, head 120 mm, so the head rises 1.5 × the cam's lift. Drawn with the helve at rest on the anvil and a lobe tip just touching the tail (contact only), ready to press.
- Brown's No. 353 (tilt hammer with the helve as a first-order lever, modified from No. 72, where it is a third-order lever).
- Parts (each has its own page): wiper-cam-2-lobe-r12-r24-b8, trip-hammer-helve-200x12, hammer-head-24x24x40, anvil-block-30x30x20, pivot-post-16x20x30-fork, linear-shafts-h6, dowel-pins-metric.
- Brown's movement No. 353 (1868) shows it; this model is a Xem Studio design following his figure, every part at true size.

parameter  value
helve  200 mm, pivot at 80 from the tail
cam  2 lobes, lift 12 mm
head lift  18 mm per blow
blows per turn  2

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. 353: figure, his text and an animation — web — Publisher's page; dimensions are facts — https://507movements.com/mm_353.html

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