An instrument for graphically recording series of observations involving two factors

摘要

205,145. Holland, E., and Collingwood, R. G. June, 13, 1922. Mothematical drawing- appliances.-An instrument for mechanically plotting the results of a series of observations involving two factors comprises a rotatable drum 1 formed with a graduated helical groove on its surface and mounted on a hollow spindle 2 which is supported in brackets 3, 4. These brackets are formed with drilled bosses 5, 7 through which pass rods 9, 10. At one end the spindle 2 carries a collar 15 provided with a handle 14 for rotating the drum, while the other end of the spindle is enlarged and a collar 16 having an internally threaded extension 161 is screwed into the enfarged part. A screw 18 engages in the extension 161 and extends into the spindle. Clamped to the screw is a bar 19 carrying a rod 22 which is screwed into a lug on an indicator 25 sliding on the rods 9, 10 carrying a pointer which can be set to any graduation on the drum. The indicator also carries a marker 44. A counting device 32 is operated by gearing 34, 33 from the drum and a carbon ribbon 70 wound on bobbins 36, 37 passes in proximity to the lower surface of the counting wheels. The drum with associated devices is pivoted to the table at 41 and can be depressed by an extension 43 of the bracket 3 after the indicator has been set, so that the marker is brought into contact with the paper. At the same time the ribbon 70 is pressed on the paper to mark the numerical value of the observation. The paper sheet 55 is mounted on parallel rollers 56, 57 so as to be traversed in a direction at right angles to the axis of the drum. To enable observations from a datum other than zero to be recorded, the drum is provided with an axially adjustable sleeve 26 graduated to the same scale as the drum but in the reverse direction, this sleeve being set to the given datum on the drum and the pointer being set to the required graduation on the sleeve.