Abstract: An indicating device adapted to indicate a flat or severely underinflated tire. The device is activated by the enlargement in the diameter of the underinflated tire caused by centrifugal force acting on the tread, and may be especially useful on dual wheels although it will work on others as well. The device includes a contact device which will be contacted by an expanding tire. That contact tilts a switch to cause a circuit to be completed to light a signal lamp in the cab of the truck.

Abstract: A tire inflation indicator is integrated into the sidewall of a tire to give a visual indication of proper pressurization. A small lamp is imbedded in the sidewall and is electrically connected through the sidewall to a pneumo-mechanical switch and battery. The switch connects the battery to the lamp when the tire pressure falls below a predetermined level.

Abstract: A method and apparatus for detecting low air pressure in pneumatic tires on a vehicle and conveying this information to the operator of the vehicle. The invention utilizes a resonating device which creates subsonic, sonic, or ultrasonic air waves when it comes in contact with the rotating sidewall of a tire having undesirably low air pressure. The apparatus provides immediate, dependable warning of potentially dangerous low pressure conditions in tires. Furthermore, the apparatus can be used to detect low air pressure in either of dual mounted tires.

Abstract: A tyre running hot due to under-inflation or other causes radiates heat. This is detected by sensors (4,27) positioned within the wheel arches. A comparison is made between each sensor output and a norm, such as ambient temperature from air temperature detectors (5) or the mean of all the sensor outputs, and significant departure from that norm triggers an alarm (22). The sensors may each be a detector (27) at the focus of a parabolic reflecting shell (28) shielded by a heat-transparent cover (30), and they will generally be positioned to face the inner side walls of the tyres. Direct wiring to the alarm unit is possible, but with a trailer (2) the signals may be locally encoded, fed by existing wiring (13) to the tractor (1) and there be decoded.

Abstract: In the combination of detachable addition members with rubber articles, particularly tire sidewalls, wherein each article has a circumferentially discontinuous first coupling portion adapted to operatively interact with a second coupling portion on the addition member for securing the member to the article, the improvement being characterized in that either the coupling portions or addition members are adapted to produce a perceptive physical change during abnormal operating conditions of the article.

Abstract: Pneumatic tire having an integral inflation indicator in the form of interdigitized groups of raised mesas affixed to the sidewall of the casing on opposite sides of the centerline of the sidewall. The two groups pivot apart by flexing of the sidewall under load when the tire is under-inflated, and they tend to overlap at the centerline when the tire is over-inflated. Indicators carried by the mesas indicate by position the extent of under-inflation or over-inflation.