Apparatus for detecting deviation in tire pressure

Claim 2

Apparatus for detecting and signalling a deviation of tire pressure from a normal level, comprising a variable sized chamber adapted to be secured to a wheel and positioned in the tire air space, said chamber having a moveable wall exposed on one side to atmospheric air pressure and on the other side to tire air pressure when positioned within a tire, rod means operatively connected to said wall and capable of being projected to protrude through the wheel rim upon a decrease in size of said chamber by movement of the said wall, and spring means acting on the said wall to maIntain it at a position such that the rod means does not protrude through the wheel rim when the tire pressure is at a normal value.

Claim 3

The detector apparatus of claim 1 further defined in that tire air pressure is applied to the inside of the moveable wall of a variable sized chamber and the spring means urges the wall to reduce the size of the chamber, whereby a drop in the tire pressure results in a reduction of the chamber size and protrusion of the rod means connected to the moveable wall.

Claim 4

The detector apparatus of claim 1 further defined in that tire air pressure is applied to the outside of the moveable wall of the variable size chamber and the spring means urges the wall to increase the size of the chamber, whereby an increase in the tire pressure results in a reduction of the chamber in size and protrusion of the rod means connected to the moveable wall.

Claim 5

Detector apparatus for securing on a wheel rim within a tire space for signalling deviation of tire pressure from a normal value by projecting a rod means through an aperture in a wheel rim upon occurrence of such deviation, said rod means being adapted to actuate a switch to make an electrical signal circuit, comprising a casing frame positioned within a tire and secured at an aperture in the wheel rim, said frame having an opening to admit tire air pressure to its interior; a hollow pin adapted to move in part through said aperture, a first bellows surrounding the hollow pin, the first bellows being secured at one end generally adjacent the aperture and at the other and inner end to the hollow pin, a first pressure disc fastened around the inner end of the hollow pin, a flexible diaphragm fastened at its inner edge to the edge of the first pressure disc and at its outer edge to the edge of the frame, the frame, first bellows, first pressure disc and flexible diaphragm thereby forming a first variable sized chamber communicating with tire air pressure, a first spring bearing on the first pressure disc to cause movement thereof and of the hollow pin in part through the aperture, when the tire pressure is reduced; a second pin slidably positioned within the hollow pin with sufficient clearance to permit air passage, having an inner portion extending beyond the end thereof, a second pressure disc attached to the inner end of the second pin, a cap surrounding a part of the inner portion, said cap having an edge secured adjacent the outer edge of the flexible diaphragm, and a hole through which passes the second pin, a second bellows fastened at one end to the edge of the second pressure disc and at the other end to the cap, the cap, second pressure disc, second bellows, flexible diaphragm and first pressure disc forming a second variable sized chamber communicating with external air pressure, a second spring within the second bellows bearing on the second pressure disc to resist movement until the tire pressure exceeds a normal value and causes reduction in size of the second variable sized chamber and movement of the second pressure disc and the second pin attached thereto to protrude in part through the aperture.

Claim 6

Detector apparatus for securing on a wheel rim within a tire space for signalling deviation of tire pressure from a normal value by projecting a rod means through an aperture in a wheel rim upon occurrence of such deviation, said rod means being adapted to actuate a switch to make an electrical signal circuit, comprising a casing frame positioned within a tire and secured at an aperture in the wheel rim, said frame having an opening to admit tire air pressure to its interior; a hollow pin adapted to move in part through said aperture, a first bellows surrounding the hollow pin, the first bellows being secured at one end generally adjacent the aperture and at the other and inner end to the hollow pin, a first pressure disc fastened around the inner end of the hollow pin, a flexible diaphragm fastened at its inner edge to the edge of the first pressure disc and at its outer edge to the edge of the frame, the frame, first bellows, first pressure disc and flexible diaphragm thereby forming a first variable sized chamber communicating with tire air pressure, a first spring bearing on the first pressure disc to cause movement thereof and of the hollow pin in part through the aperture, when the tire pressure is reduced; a second pin slidably positioned within the hollow pin with sufficient clearance to permit air passage, having an inner portion extending beyond the end thereof, a second pressure disc attached to the inner end of the second pin, a cap surrounding a part of the inner portion, said cap having an edge secured adjacent the outer edge of the flexible diaphragm, and a hole through which passes the second pin, a second bellows fastened at one end to the edge of the second pressure disc and at the other end to the cap, the cap, second pressure disc, second bellows, flexible diaphragm and first pressure disc forming a second variable sized chamber communicating with external air pressure, a second spring within the second bellows bearing on the second pressure disc to resist movement until the tire pressure exceeds a normal value and causes reduction in size of the second variable sized chamber and movement of the second pressure disc and the second pin attached thereto to protrude in part through the aperture.

Claim 7

Apparatus for detecting and signalling deviations of tire pressure from normal value comprising a generally cylindrical casing, adapted to be secured tangentially to a wheel rim within the tire space, said casing having a partition adjacent one end, the other end being open, a tube projecting from the side of the casing and adapted to project through in sealed relation to an aperture in the rim, a rod slidably positioned in said tube with sufficient clearance to provide access of atmospheric air to the interior of the casing, a cross bar attached to the end of the rod within the casing and a spring positioned around the rod within the casing urging the rod inwardly, a high pressure wedge and a low pressure wedge slidably contained in the casing, each of said wedges having its wide end facing an end of the casing and the narrow end directed toward and normally engaging the cross bar, a rod extension from the wide end of the high pressure wedge connected to a first pressure disc, a first, tubular flexible membrane attached at one end to the margin of said disc and at the other end to the open end of the casing, a hollow rod extension from the wide end of the low pressure wedge, said rod passing through a hole in the partition in the casing and to and connected to a second pressure disc, a bellows surrounding the hollow rod extension and attached at one end to the rod and at the other end to the partition, a second tubular flexible membrane connected at one end to the edge of the second pressure disc and at the other end to the end of the casing, a gas tight cap surrounding the second pressure disc and, the second tubular flexible diaphragm, the said cap forming with the second pressure disc and second tubular membrane a variable volume chamber communicating to outside air pressure by the passage through the hollow rod extension, an aperture in the casing providing access to maintain tire pressure in the space defined by the second bellows, the partition, the second pressure disc and the second tubular, flexible membrane, and a spring positioned in the cap urging the second pressure disc against the force of the tire pressure on the pressure disc.

Claim 8

Apparatus for detecting and signalling deviations of tire pressure from normal value comprising a generally cylindrical casing, adapted to be secured tangentially to a wheel rim within the tire space, said casing having a partition adjacent one end, the other end being open, a tube projecting from the side of the casing and adapted to project through in sealed relation to an aperture in the rim, a rod slidably positioned in said tube with sufficient clearance to provide access of atmospheric air to the interior of the casing, a cross bar attached to the end of the rod within the casing and a spring positioned around the rod within the casing urging the rod inwardly, a high pressure wedge and a low pressure wedge slidably contained in the casing, each of said wedges having its wide end facing an end of the casing and the narrow end directed toward and normally engaging the cross bar, a rod extension from the wide end of the high pressure wedge connected to a first pressure disc, a first, tubular flexible membrane attached at one end to the margin of said disc and at the other end to the open end of the casing, a hollow rod extension from the wide end of the low pressure wedge, said rod passing through a hole in the partition in the casing and to and connected to a second pressure disc, a bellows surrounding the hollow rod extension and attached at one end to the rod and at the other end to the partition, a second tubular flexible membrane connected at one end to the edge of the second pressure disc and at the other end to the end of the casing, a gas tight cap surrounding the second pressure disc and, the second tubular flexible diaphragm, the said cap forming with the second pressure disc and second tubular membrane a variable volume chamber communicating to outside air pressure by the passage through the hollow rod extension, an aperture in the casing providing access to maintain tire pressure in the space defined by the second bellows, the partition, the second pressure disc and the second tubular, flexible membrane, and a spring positioned in the cap urging the second pressure disc against the force of the tire pressure on the pressure disc.