Tire pressure indicator
First Claim
1. A tire pressure indicator comprising a housing having means thereon for attaching it to a vehicle wheel, a cylinder in said housing, a piston slideable axially in said cylinder, a switch actuator supported by said piston for movement therewith, means on said cylinder adapted to be connected with the valve stem of a vehicle tire for subjecting one side of the piston to the pressure of the air in the tire, a spring yieldably opposing movement of the piston in response to the air pressure exerted against said one side thereof so that the position of said switch actuator in a direction axially of said cylinder is determined by the extent to which the tire air pressure overcomes the force on the piston produced by said spring, an indicator light on said housing and means in said housing forming an electrical circuit for energizing the indicator light, said circuit means including a switch disposed in said housing in a predetermined position axially of said cylinder for actuation by said switch actuator when the tire pressure is below a predetermined value and thereby energize said signal light.
1 Assignment
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Accused Products
Abstract
A wheel-mounted tire pressure indicator which includes a housing enclosing a pneumatically-actuated pressure indicia scale as well as a self-contained battery and circuit for energizing a signal light on the housing when the tire pressure is below a predetermined selected value.
21 Citations
20 Claims
- 1. A tire pressure indicator comprising a housing having means thereon for attaching it to a vehicle wheel, a cylinder in said housing, a piston slideable axially in said cylinder, a switch actuator supported by said piston for movement therewith, means on said cylinder adapted to be connected with the valve stem of a vehicle tire for subjecting one side of the piston to the pressure of the air in the tire, a spring yieldably opposing movement of the piston in response to the air pressure exerted against said one side thereof so that the position of said switch actuator in a direction axially of said cylinder is determined by the extent to which the tire air pressure overcomes the force on the piston produced by said spring, an indicator light on said housing and means in said housing forming an electrical circuit for energizing the indicator light, said circuit means including a switch disposed in said housing in a predetermined position axially of said cylinder for actuation by said switch actuator when the tire pressure is below a predetermined value and thereby energize said signal light.
- 15. A tire pressure indicator comprising a non-magnetic housing adapted to be mounted on a vehicle wheel, a non-magnetic cylinder in said housing projecting outwardly of the housing at one end for connection with a conduit extending from the valve stem of the vehicle wheel tire so that the tire pressure is applied to the cylinder, said cylinder having a non-magnetic piston slideably arranged therein, said piston being biased axially away from said one end of the cylinder in response to the application of air pressure from the tire at said one end thereof, said piston having one end projecting axially outwardly beyond the other end of the cylinder, a non-magnetic retainer fixedly mounted on said projecting end of the cylinder, a magnet mounted on said retainer, a compression spring bearing against said retainer at one end with its opposite end bearing against a wall of said housing for biasing said piston toward said one end of the cylinder, a signal light on said housing and means in said housing forming a circuit for energizing said light, said circuit means including a magnetically responsive switch for closing the circuit to the light when the magnet is displaced axially of the cylinder to a position in close proximity to said switch.
Specification