| 摘要 |
<p>A device for manual operation, intended for learning the concepts of a positional numbering notation system, comprises: - a number of numbered toothed wheels (20a,20b,20c) disposed side by side parallel to a plane (10), rotatable and located at different levels, each tooth of each numbered toothed wheel (20a,20b,20c) being marked with a digit and these digits being located in their correct succession, each numbered toothed wheel (20a,20b,20c) presenting some teeth available for being manually displaced; - and a number, corresponding to the number of the numbered toothed wheels (20a,20b,20c) less one, of transmission wheels (40a,40b), located side by side and rotatable, each transmission toothed wheel (40a,40b) meshing with the foregoing numbered toothed wheel but not meshing with the subsequent numbered toothed wheel, and being provided with a carry tooth (42a,42b) suitable to displace between a non-operative attitude, in which it cannot engage the subsequent numbered toothed wheel, and an operative attitude, in which it engages the subsequent numbered toothed wheel in order to impart to the same an angular displacement, to each transmission toothed wheel (40a,40b) being associated a mechanism suitable for displacing the carry tooth (42a,42b) from its non operative attitude to its operative attitude when the transmission toothed wheel (40a,40b) lies within an arc corresponding to the operative engagement of this carry tooth with the subsequent numbered toothed wheel (20a,20b,20c).</p> |
