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Geneva stop finger wheel: Ø4 pin at r 23.51, Ø41.02 locking disc, Ø6 bore

What is the finger wheel of a Geneva stop? · Modern device · basis: Xem Studio design following Brown's figure (1868); true size, no printing allowance

Also called: geneva driver, finger wheel, maltese cross driver, stop work finger, rueda de dedo de cruz de Malta, Fingerrad des Malteserkreuz-Gesperrs

Exact dimensions. True size, with no printing tolerance added.

length
53.02 mm
width
53.02 mm
height
10.0 mm

Notes

  • Driver of a Geneva (Maltese cross) stop for a star on 40 mm centres: one Ø4 × 6 pin at radius 23.51 (= a·sin(π/5), so it enters and leaves the star's slots radially), a Ø41.02 × 6 locking disc that holds the star still between indexings, and a Ø53.02 × 4 carrier plate under both; Ø6 bore.
  • The locking disc is cut back by the exact sweep of the star through one indexing (the star's outline in the wheel's frame at every 0.1° of the 108° engagement, a clearance surface kept as 0 mm facets), so disc and star only ever touch: on the disc's rim while locked, on the pin while indexing.
  • Xem Studio design following Brown's figure; true size, no printing allowance (apply your own to the mating features).

Geneva stop finger wheel: Ø4 pin at r 23.51, Ø41.02 locking disc, Ø6… size chart

dimensionvalue
pinØ4 at r 23.51
locking discØ41.02 × 6
carrierØ53.02 × 4
centres with the star40 mm
engagement±54° of the wheel's turn
boreØ6

Where the files are

Other publishers' files are linked, not hosted. "verify" = check the license at the link before commercial use.

Henry T. Brown (1868, public domain)Five Hundred and Seven Mechanical Movements — scan on archive.orgwebPublisher's page; dimensions are facts
507movements.comBrown's movement No. 212: figure, his text and an animationwebPublisher's page; dimensions are facts
Xem StudiodrawingwebPublisher's page; dimensions are facts

Free files

★ Free files 1 parts. Xem Studio design: free to use, print and sell things from; not to be republished as files. Xem Studio Design License. index.json

geneva-stop-finger-wheel-r23-5-pin4finger wheel, axis Z, disc z 0..6, carrier z -4..0, pin on +XSTEP · STL
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Plain text: sheet.txt · JSON: /api/geometry?object=geneva-stop-finger-wheel-r23-5-pin4

Geneva stop finger wheel: Ø4 pin at r 23.51, Ø41.02 locking disc, Ø6 bore, isometric render of a generated part
Render of geneva-stop-finger-wheel-r23-5-pin4 from the free STEP; not to scale.

Fits with

Geneva stop (Maltese cross stop-work): finger wheel limited to four turns, isometric render of a generated part
Geneva stop (Maltese cross stop-work): finger wheel limited to four turns5 sizes★ 1 file

Questions

What is the finger wheel of a Geneva stop?

Driver of a Geneva (Maltese cross) stop for a star on 40 mm centres: one Ø4 × 6 pin at radius 23.51 (= a·sin(π/5), so it enters and leaves the star's slots radially), a Ø41.02 × 6 locking disc that holds the star still between indexings, and a Ø53.02 × 4 carrier plate under both; Ø6 bore.