Magnetically activated sensor
An impact sensor includes a hollow container having a plurality of walls, a first magnetic member attached to one of the plurality of walls, and a second magnetic member magnetically attracted to the first magnetic member. A marking device is disposed on the second magnetic member. When a force applied to the sensor exceeds a first predetermined value, the marking device engages one of the plurality of walls and wherein the marking device marks the one of the plurality of walls.
1. An impact sensor comprising:
a hollow sensor body having an open end and a closed end, the closed end defining a chamber;
a cap extending over the open end, the cap having:
a wall extending into the sensor body, the wall defining a compartment; and
an annular disc connected to the wall, the annular disc having a through-opening formed therein;
a first magnetic member located proximate to the open end of the sensor body;
a second magnetic member magnetically attracted to the first magnetic member and covering the through-opening;
a colored fluid in the compartment; and
a removable pull tab between the second magnetic member and the through opening.
2. The impact sensor according to claim 1 , wherein the colored fluid is between the first magnetic member and the second magnetic member.
3. The impact sensor according to claim 1 , wherein the cap comprises a first cap member forming a first wall portion of the wall and a second cap member forming a remaining wall portion of the wall.
4. The impact sensor according to claim 1 , wherein the sensor body includes a radial cavity extending around a periphery of thereof, and wherein the cap comprises a detent sized to fit into the radial cavity.
5. The impact sensor according to claim 1 , wherein the first magnetic member magnetically attracts the second magnetic member with a predetermined force.
6. The impact sensor according to claim 5 wherein, when a force exceeding the predetermined force is applied to the sensor, the second magnetic member is moved away from the through-opening.
7. The impact sensor according to claim 6 , wherein, when the second magnetic member is moved away from the through-opening, the dye is able to move into the chamber.
8. The impact sensor according to claim 1 , further comprising a liquid disposed in the chamber.
9. The impact sensor according to claim 1 , wherein the pull tab comprises a free end extending outwardly of the sensor body.
10. An impact sensor comprising:
a hollow body having a chamber therein;
a wall being disposed in the chamber;
an annular disc attached to the wall such that the wall and the annular disc define a chamber, the annular disc having a through-opening formed therein;
a dye disposed in the chamber;
a magnetically attractive ball covering the through-opening; and
a magnetic element biasing the ball over the through-opening.
11. The impact sensor according to claim 10 , further comprising a liquid in the chamber between the wall and the body.
12. The impact sensor according to claim 10 , further comprising a pull tab removably located between the magnetically attractive ball and the through-opening.
13. The impact sensor according to claim 10 , wherein the magnetically attractive element is selected to provide a predetermined magnetic force between the magnetically attractive element and the magnetically attractive ball.
14. The impact sensor according to claim 10 , wherein the dye comprises a dry powder.
15. The impact sensor according to claim 10 , wherein the magnetically attractive element comprises a neodymium magnet.
16. The impact sensor according to claim 10 , wherein the magnetically attractive ball comprises a steel ball.
17. The impact sensor according to claim 10 , wherein the wall comprises a first wall portion and a second wall portion.
18. The impact sensor according to claim 10 , wherein the body is constructed from a visually clear material.
19. The impact sensor according to claim 10 , wherein the magnetic attraction between the magnetically attractive element and the magnetically attractive ball determines a predetermined force threshold level that retains the magnetically attractive ball over the through-opening.