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Structure of mechanism |
| Function |
This device features a sighting telescope with a lens, but the eyepiece is missing. A knob enables the image to be focused. The telescope is fixed to a vertical armature featuring an arc of circle divided into tangents and indicating the slope by one metre per division on the graduations next to the eyepiece. It can thus pivot in the vertical plane to measure the slope. A screw is used to block the rotation. The telescope is attached to a first circular plate which can turn in the horizontal plane.
On its upper face are two verniers, enabling a measurement precision of 1/30 of one degree. A second plate located outside the first can turn independently. On its upper face there are graduations giving angle values with a precision of ½ a degree. A vice closed by a screw on its upper part enables these two parts to be locked together when required. Below and connected to the second plate is another disc which can turn independently of the base. As before, a vice closed by a screw in its lower part can lock the two parts together if required. The base has three footscrews to adjust the horizontal level. This is verified by a spirit level in a metal tube which is located on the first plate.
For each measurement it is necessary to verify that the device, fixed to a tripod, is horizontal. This is done using the footscrews and the spirit level. The vertical circle arc is divided into tangents and gives the slope by one metre per graduation division. This device is used in topography to survey building sites or implement construction projets. It can measure the slopes of various points in an indirect manner with the help of a target. |
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Guidance function |
| Trace of a dedicated point on follower |
 Open trace |
| Dimension of mechanism |
spatial |
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