Pendular accelerometer for detecting threshold oscillation values
A device for measuring the acceleration of a moving body includes a pendulum capable of oscillating about an instantaneous center of rotation and a detection system capable of detecting an oscillation of the pendulum that is likely to result from the acceleration. The pendulum has a geometric configuration enabling it to interact with the detection system. The geometric configuration is such that the detection system only indicates an oscillation of the pendulum that exceeds a threshold oscillation value.
1. A device for measuring an acceleration of a moving body, the device comprising:
a pendulum configured to oscillate about an instantaneous center of rotation;
a detection system configured to detect an oscillation of said pendulum resulting from the acceleration;
said pendulum having a geometric configuration enabling said pendulum to interact with said detection system, and said geometric configuration configured to only allow said detection system to indicate an oscillation of said pendulum exceeding a threshold oscillation value; and
a brake configured to damp said pendulum only when an oscillation exceeds said threshold oscillation value.
2. The measuring device according to claim 1 , wherein said detection system includes a detector disposed perpendicular to a plane of oscillation of said pendulum.
3. The measuring device according to claim 1 , wherein said detection system includes an emitter.
4. The measuring device according to claim 1 , wherein said geometric configuration of said pendulum includes an interface between a first medium and a second medium at a position of said pendulum intended to be opposite said detection system when said oscillation is equal to said threshold oscillation value, and only one of said first and second media is capable of interacting with said detection system to indicate that said threshold oscillation value has been exceeded.
5. The measuring device according to claim 1 , which further comprises a system configured to adjust said threshold oscillation value to be detected by said detection system.
6. The measuring device according to claim 2 , wherein said detector is one of a plurality of detectors each configured to detect that a threshold oscillation value has been exceeded.
7. The measuring device according to claim 4 , wherein said geometric configuration of said pendulum includes said interface between said first and second media at another position of said pendulum intended to be opposite said detection system when said oscillation is equal to another threshold value.
8. The measuring device according to claim 7 , wherein said pendulum has a center of gravity and a symmetrical shape with respect to a plane of symmetry passing through said center of gravity and said instantaneous center of rotation, said plane of symmetry being perpendicular to a plane of oscillation of said pendulum, said position and said other position being equidistant from said plane of symmetry, and a single medium extending from said first position to said second position.
9. The measuring device according to claim 6 , wherein said detection system includes a single detector and a single emitter, and said geometric configuration is configured to allow said detection system to indicate that said threshold oscillation value has been exceeded and another threshold oscillation value has been exceeded.
10. The measuring device according to claim 8 , wherein said pendulum is a flat body, and said single medium extending from said first position to said second position forms a window in said flat body.
11. The measuring device according to claim 1 , which further comprises a ball joint about which said brake is movable.
12. The measuring device according to claim 1 , wherein said brake includes a friction track.
13. The measuring device according to claim 1 , wherein said brake includes a permanent magnet.
14. The measuring device according to claim 13 , wherein said brake is a magnetic trigger switch configured to detect an oscillation of said pendulum.