Pyrotechnic devices

Claim 2

A pressure switch for submarine use comprising, a capillary tube having a narrow bore, a closed end and an open end, two electric terminals positioned within said bore a predetermined distance from said open end, each of said electric terminals being spaced adjacent but out of contact with the other, said electric terminals being adapted to be connected to an electric circuit external of said tube, said bore containing air and being sufficiently narrow to prevent the escape of the air from said bore when the same is immersed in sea water so that the sea water enters said bore a distance proportional to the pressure of the sea water on the air in said bore which is dependent upon the depth of immersion of said switch in the sea, whereby when said electric terminals are connected to an external electric circuit so that when said switch is immersed in sea water to a depth such that the sea water penetrates said bore and contacts said electric terminals, said electric circuit external of said tube is completed.

Claim 3

A pressure switch as claimed in claim 1 wherein one of said electric terminals is magnesium and the other of said electric terminals is selected from the group consisting of silver and nickel.

Claim 4

A pressure switch as claimed in claim 2 wherein the internal diameter of said bore is from about 1 to 2 mm.

Claim 5

A pressure switch as claimed in claim 1 which further comprises, in an electrical circuit connected to the terminals outside the tube, a current amplification means.

Claim 6

A pressure switch as claimed in claim 4 wherein the current amplification means is transistorized

Claim 7

A pressure switch as claimed in claim 1 wherein the internal diameter of said bore is from 1 to 2 mm.

Claim 8

A pressure switch as claimed in claim 6 wherein one of said electric terminals is anodic and wherein said anodic terminal is of a material selected from the group consisting of magnesium and high magnesium alloys.

Claim 9

A pressure sWitch as claimed in claim 7 wherein one of said electric terminals is cathodic and wherein said cathodic terminal is of a material selected from the group consisting of silver and nickel.

Claim 10

A submarine-signalling device comprising in combination a battery, a detonator, a pressure switch, and an amplifier, said battery, detonator and amplifier being connected in a series circuit whereby a small amount of current insufficient to activate said detonator flows through said circuit, said pressure switch being connected in parallel across said detonator and said amplifier, said pressure switch comprising a capillary tube having a narrow bore, a closed end and an open end, two electric terminals positioned within said bore a predetermined distance from said open end, each of said electric terminals being spaced adjacent but out of contact with the other, said electric terminals being connected across said detonator and amplifier, said bore containing air and being sufficiently narrow to prevent the escape of the air from said bore when the same is immersed in sea water so that the sea water enters said bore and distance proportional to the pressure of the sea water on the air in said bore which is dependent upon the depth of immersion of said switch in the sea, said predetermined distance being the distance that sea water will penetrate said bore when said switch is immersed to a predetermined depth below the level of the sea, whereby when said submarine-signalling device is immersed in sea water to said predetermined depth the sea water penetrates said bore said predetermined distance and contacts and electrically connects said electrical terminals of said pressure switch thereby completing the electrical connection across said detonator and said amplifier which results in the passage of an amount of current through said detonator sufficient to activate said detonator.

Claim 11

A submarine-signalling device comprising in combination a battery, a detonator, a pressure switch, and an amplifier, said battery, detonator and amplifier being connected in a series circuit whereby a small amount of current insufficient to activate said detonator flows through said circuit, said pressure switch being connected in parallel across said detonator and said amplifier, said pressure switch comprising a capillary tube having a narrow bore, a closed end and an open end, two electric terminals positioned within said bore a predetermined distance from said open end, each of said electric terminals being spaced adjacent but out of contact with the other, said electric terminals being connected across said detonator and amplifier, said bore containing air and being sufficiently narrow to prevent the escape of the air from said bore when the same is immersed in sea water so that the sea water enters said bore and distance proportional to the pressure of the sea water on the air in said bore which is dependent upon the depth of immersion of said switch in the sea, said predetermined distance being the distance that sea water will penetrate said bore when said switch is immersed to a predetermined depth below the level of the sea, whereby when said submarine-signalling device is immersed in sea water to said predetermined depth the sea water penetrates said bore said predetermined distance and contacts and electrically connects said electrical terminals of said pressure switch thereby completing the electrical connection across said detonator and said amplifier which results in the passage of an amount of current through said detonator sufficient to activate said detonator.

Claim 12

A submarine-signalling device as claimed in claim 9 wherein the internal diameter of said bore is from about 1 to 2 mm. and wherein said amplifier is a transistor amplifier.

Claim 13

A submarine-signalling device as claimed in claim 10 wherein in said pressure switch one of said electric terminals is magnesium and the other of said electric terminals is selected from the group consisting of silver and nickel.