Les instruments du calcul savant > Instruments d'intégration conservés au musée des arts et métiers

Integraph

Integraph with transfer of direction by filament, system Abdank-Abakanowicz/Napoli
Maker: P. Barbier & Cie, Paris (see A.-A. in Comptes Rendus of the Académie des Sciences, footnote (2)); instrument no.: none (presumably one-of-a-kind); c1885
Inventory: CNAM, inventory no.
13588-0000-
Details: Not signed. Entry CNAM: 1903, donation by Mrs. Napoli
References: C.R. of the AdS, 14.9.1885; Abdank-Abakanowicz 1886, 38-43 and Abdank-Abakanowicz 1889, 35-37 (each with two illustrations). Instrument mentioned in Cat. CNAM 1905, 156 and Cat. CNAM 1942, 130

Fig. 31, Abdank-Abakanowicz 1886, 39 = Fig. 34, Abdank-Abakanowicz 1889, 34

The solution of the transfer of direction derived from a given curve to a knife-edged wheel was problematic for a very long time. A further variant, which came out of the cooperation between Bruno Abdank-Abakanowicz (1852-1900) and David Napoli (1840-1890), resulted in the following model which made use of wheels connected by a filament.

Thus the principle of transfer remains almost unchanged when compared with the use of cogwheels (see CNAM 13300-0001-), but its constructional side is different in many respects. The idea behind this instrument is to get rid of the play that can happen when using toothed wheels or cogwheels. It was known for a long time that the use of a filament would almost eliminate any play in the transfer. On the other hand the filament (which in reality is a non-elastic thread or a thin wire, commonly a silver wire was used) must permanently be held absolutely tight. This means additional mechanisms because the distance between the two pairs of wheels (corresponding to the two pairs of cog-wheels) changes permanently. Additionally, keeping the filament tight must not hamper the easy movement of the tracer pin.

Fig. 34, Abdank-Abakanowicz 1886, 43 = Fig. 37, Abdank-Abakanowicz 1889, 38

     

Integraph with transfer of direction by filament, system Abdank-Abakanowicz/Napoli,
c1885, details (CNAM 13558-0000)