Tilt sensor

Claim 2

A sensing system for detecting predetermined angles of tilt misalignment of positionally aligned equipment, said system comprising, in combination: a power supply; a pair of series connected mercury switches coupled to said power supply and mounted on said equipment with opposite tilt sensing orientations, for detecting both positive and negative angles of tilt misalignment; signal output means series connected with said pair of mercury switches across said power supply and operative to be energized by said power supply when said mercury switches are in a normally closed circuit condition and to be deenergized when one of said mercury switches is in an open circuit condition, which occurs in response to a predetermined tilt misalignment of said equipment; and electrical circuit means connected to said signal output means for time delaying deenergization thereof, whereby said system is substantially insensitive to vibration of said equipment.

Claim 3

A sensing system for detecting predetermined angles of tilt misalignment of positionally aligned equipment, said system comprising, in combination: a power supply; a pair of series connected mercury switches coupled to said power supply and mounted on said equipment with opposite tilt sensing orientations, for detecting both positive and negative angles of tilt misalignment; signal output means series connected with said pair of mercury switches across said power supply and operative to be energized by said power supply when said mercury switches are in a normally closed circuit condition and to be deenergized when one of said mercury switches is in an open circuit condition, which occurs in response to a predetermined tilt misalignment of said equipment; and electrical circuit means connected to said signal output means for time delaying deenergization thereof, whereby said system is substantially insensitive to vibration of said equipment.

Claim 4

A sensing system for detecting predetermined angles of tilt misalignment of positionally aligned equipment, said system comprising, in combination: a power supply; a pair of series connected mercury switches coupled to said power supply and mounted on said equipment with opposite tilt sensing orientations, for detecting both positive and negative angles of tilt misalignment; signal output means series connected with said pair of mercury switches across said power supply and operative to be energized by said power supply when said mercury switches are in a normally closed circuit condition and to be deenergized when one of said mercury switches is in an open circuit condition, which occurs in response to a predetermined tilt misalignment of said equipment; and electrical circuit means connected to said signal output means for time delaying deenergization thereof, whereby said system is substantially insensitive to vibration of said equipment.

Claim 5

A sensing system according to claim 1 wherein said signal output means comprises a relay having contacts and a coil, said relay coil being series connected with said switch means across said power supply.

Claim 6

A sensing system according to claim 2 wherein said delay circuit means comprises a capacitor connected across said relay coil, said capacitor being charged through said switch means during energization of said relay coil and being discharged through said relay coil upon deenergization of said relay in response to actuation of said switch means to an open circuit condition, whereupon the RC time constant for delaying relay deenergization is substantially determined by the capacitance value of said capacitor and the resistance of said relay coil.

Claim 7

A sensing system according to claim 3 wherein said power supply is a direct current supply, and further including a resistor series connected between said direct current power supply and said switch means for substantially determining the charge time of said capacitor, the resistance of said resistor being substantially less than the resistance of said relay coil, whereby the charge time for energizing said relay coil is substantially less than the discharge time for deenergizing said relay coil.

Claim 8

A sensing system for detecting predetermined angles of tilt misalignment of positionally aligned equipment, said system comprising, in combination: a power supply; level sensing switch means comprising a pair of series connected mercury switches coupled to said power supply and mounted on said equipment with opposite tilt sensing orientations, for detecting both positive and negative angles of tilt misalignment; signal output means coupled to both said power supply and said switch means and operative to be energized by said power supply when said switch means is in a first operating state, which is the normal condition, and to be deenergized when said switch means is in a second operating state, which occurs in response to a predetermined tilt misalignment of said equipment; and electrical circuit means connected to said signal output means for time delaying said deenergization thereof, whereby said system is substantially insensitive to vibration of said equipment.

Claim 9

A sensing system for detecting predetermined angles of tilt misalignment of positionally aligned equipment, said system comprising, in combination: a power supply; level sensing switch means comprising a pair of series connected mercury switches coupled to said power supply and mounted on said equipment with opposite tilt sensing orientations, for detecting both positive and negative angles of tilt misalignment; signal output means coupled to both said power supply and said switch means and operative to be energized by said power supply when said switch means is in a first operating state, which is the normal condition, and to be deenergized when said switch means is in a second operating state, which occurs in response to a predetermined tilt misalignment of said equipment; and electrical circuit means connected to said signal output means for time delaying said deenergization thereof, whereby said system is substantially insensitive to vibration of said equipment.

Claim 10

A sensing system according to claim 5 wherein said switch means further includes an adjusting plate, and a pair of bracketed potting shells mounted on said adjusting plate by respective sets of spring loaded calibration screws, each of said mercury switches being encapsulated into a respective one of said potting shells, and said encapsulated switches being adjustable by means of said calibration screws so that both switches are closed when said adjusting plate is level.

Claim 11

A sensing system according to claim 6 wherein said switch means further includes a mounting plate attached to said equipment, and said adjusting plate is mounted on said mounting plate by a set of spring loaded leveling screws, said adjusting plate being adjustable to a level position by means of said leveling screws.

Claim 12

For use in an airplane landing guidance system including a pair of light fixtures displaced relative to each other along a runway and emitting light beams pointed at preselected acute angles upwardly from and parallel to said runway to define a safe landing corridor therebetween, tilt sensing means associated with each of said light fixtures for disabling said system when either of said light beams deviates by a predetermined amount from the preselected acute angle therefor, said tilt sensing means comprising: a direct current power supply; a plurality of series connected normally closed mercury switches mounted on each of said light fixtures for detecting both positive and negative angles of tilt misalignment; a relay having a coil and a set of contacts for enabling or disabling energization of said light fixtures, said relay coil and said plurality of mercury switches being series connected across said power supply; and a capacitor connected across said relay coil, said capacitor being charged through said mercury switches during energization of said relay coil, whereupon said relay contacts are actuated for enabliNg energization of said light fixtures, and said capacitor being discharged through said relay coil, upon actuation of one of said mercury switches to an open circuit condition, whereby deenergization of said relay coil is delayed according to the RC time constant determined by the capacitance value of said capacitor and the resistance value of said relay coil so as to render said relay substantially insensitive to vibration of said light fixtures.

Claim 13

For use in an airplane landing guidance system including a pair of light fixtures displaced relative to each other along a runway and emitting light beams pointed at preselected acute angles upwardly from and parallel to said runway to define a safe landing corridor therebetween, tilt sensing means associated with each of said light fixtures for disabling said system when either of said light beams deviates by a predetermined amount from the preselected acute angle therefor, said tilt sensing means comprising: a direct current power supply; a plurality of series connected normally closed mercury switches mounted on each of said light fixtures for detecting both positive and negative angles of tilt misalignment; a relay having a coil and a set of contacts for enabling or disabling energization of said light fixtures, said relay coil and said plurality of mercury switches being series connected across said power supply; and a capacitor connected across said relay coil, said capacitor being charged through said mercury switches during energization of said relay coil, whereupon said relay contacts are actuated for enabliNg energization of said light fixtures, and said capacitor being discharged through said relay coil, upon actuation of one of said mercury switches to an open circuit condition, whereby deenergization of said relay coil is delayed according to the RC time constant determined by the capacitance value of said capacitor and the resistance value of said relay coil so as to render said relay substantially insensitive to vibration of said light fixtures.