Roll-over shunt sensor
First Claim
1. An automobile mounted tilt and acceleration sensor comprising:
- a housing;
a reed switch mounted on the housing;
a magnet mounted to the housing, positioned vertically spaced from the reed switch, the magnet producing a magnetic field sufficient to cause the reed switch to actuate;
a magnetic shunt mounted to the housing by a pendulum with a pivot point vertically above the reed switch and the magnet, the shunt positioned to hang between the reed switch and the magnet, the magnetic shunt mounted to swing through an arc centered between the reed switch and the magnet, the shunt preventing actuation of the reed switch when it is positioned between the magnet and the reed switch;
two opposed shunt stops mounted on the housing and positioned to allow the shunt to swing out from between the reed switch and the magnet along the arc;
a selected pendulum mass coincident with the shunt; and
a means for biasing the shunt between the reed switch and the magnet having a selected restoring force, wherein the pendulum mass is selected such that gravity acting on the selected mass is greater than the selected restoring force, when the housing is tilted beyond a selected angle, and wherein the stops are positioned to position the shunt so that the means for biasing can move the shunt to a position between the magnet and the reed switch when the housing is returned to a vertical position.
7 Assignments
0 Petitions
Accused Products
Abstract
A ferromagnetic shunt is pivotally mounted to a housing to form a pendulum which swings between a reed switch and a magnet. As long as the shunt remains between the reed switch and the magnet the reed switch remains open. The shunt is held or biased between the magnet and the reed switch by the force of the magnetic attraction between the shunt and the magnet. The mass of the shunt acts as both a tilt sensor which responds to gravity and an accelerometer sensitive to crash-induced accelerations. The reed switch, magnet and shunt are mounted in a housing which positions the reed switch and magnet and controls the maximum range of motion of the shunt. The magnet is located between two sidewardly spaced pendulum arms, which allow the shunt to swing out from between the reed switch and the magnet in two opposite directions.
43 Citations
12 Claims
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1. An automobile mounted tilt and acceleration sensor comprising:
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a housing; a reed switch mounted on the housing; a magnet mounted to the housing, positioned vertically spaced from the reed switch, the magnet producing a magnetic field sufficient to cause the reed switch to actuate; a magnetic shunt mounted to the housing by a pendulum with a pivot point vertically above the reed switch and the magnet, the shunt positioned to hang between the reed switch and the magnet, the magnetic shunt mounted to swing through an arc centered between the reed switch and the magnet, the shunt preventing actuation of the reed switch when it is positioned between the magnet and the reed switch; two opposed shunt stops mounted on the housing and positioned to allow the shunt to swing out from between the reed switch and the magnet along the arc; a selected pendulum mass coincident with the shunt; and a means for biasing the shunt between the reed switch and the magnet having a selected restoring force, wherein the pendulum mass is selected such that gravity acting on the selected mass is greater than the selected restoring force, when the housing is tilted beyond a selected angle, and wherein the stops are positioned to position the shunt so that the means for biasing can move the shunt to a position between the magnet and the reed switch when the housing is returned to a vertical position. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A tilt sensor comprising:
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a housing; a reed switch mounted to the housing; a magnet mounted to the housing above the reed switch; a ferromagnetic shunt member positioned above the reed switch; and at least one pendulum arm which extends upwardly from the shunt member to a pivotal mounting on the housing at a position above the magnet, the shunt member being mounted by the at least one pendulum arm for swinging movement on the housing between a position where the shunt member is interposed between the magnet and the reed switch, and an activated position where the shunt member is not interposed between the magnet and the reed switch, wherein the at least one pendulum arm is mounted to the housing such that the shunt member may swing freely to move out of interposition between the magnet and the reed switch by travel in a first direction and a second opposite direction. - View Dependent Claims (8, 9, 10, 11, 12)
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Specification