Tire pressure warning system
First Claim
1. A tire pressure sensing apparatus for detecting air pressures too high or too low in a revolving tire, comprising:
- a tire tap removably attached to a tire valve stem;
an air delivery tube, having a first tube end attached to said tap, disposed along an outside surface of a wheel mounting the tire and through an opening in the wheel, said tube extending from the opening adjacent an axis of rotation of the tire to a second tube end;
a cylinder pneumatically connected at a cylinder end to said second tube end of said tube;
non-rotating case for holding said cylinder rotatably therewithin;
a piston slidably disposed within said cylinder, said piston and said cylinder together preventing leakage of pressurized air past said piston;
force means to urge said piston toward said cylinder end;
a shaft coaxial with said cylinder and attached to said piston at a first shaft end; and
electrical switching means attached to said case, said switching means including first and second electrical contact means which are responsive to axial motions of said shaft to close said first electrical contact means when said piston reaches a low pressure piston position and close said second electrical contact means when said piston reaches a high pressure piston position; and
electrical alerting means responsive to said switching means;
wherebya driver may be alerted to high or low pressure in the tire.
0 Assignments
0 Petitions
Accused Products
Abstract
An apparatus is for sensing the presure in a vehicle'"'"'s tires while the tire is revolving. Tire pressure is tapped at the valve stem. Pressurized air is passed through a delivery tube from the valve stem to a pressure sensor which detects either a too high or a too low pressure from the tire. The delivery tube passes from the valve stem over the outer face of the tire to the center of the wheel. There it enters a hole bored along the axis of rotation of the wheel and passes through the wheel and suspension parts until it reaches a free space. Here the rotating tube connects to an inner, rotary master cylinder of the sensor. The master cylinder includes a piston acted upon by the pressurized air from the tube. A spring opposes the air pressure, so that the axial displacement of the piston is proportional to the tire pressure. An electrical contact is moved by the piston; it can touch either of two stationary contacts, whose positions correspond to over pressure or under pressure, and complete circuits to light warning lamps for the driver. The master cylinder spins within an outer case which is fastened to the wheel suspension and which contains the stationary contacts.
13 Citations
16 Claims
-
1. A tire pressure sensing apparatus for detecting air pressures too high or too low in a revolving tire, comprising:
-
a tire tap removably attached to a tire valve stem; an air delivery tube, having a first tube end attached to said tap, disposed along an outside surface of a wheel mounting the tire and through an opening in the wheel, said tube extending from the opening adjacent an axis of rotation of the tire to a second tube end; a cylinder pneumatically connected at a cylinder end to said second tube end of said tube; non-rotating case for holding said cylinder rotatably therewithin; a piston slidably disposed within said cylinder, said piston and said cylinder together preventing leakage of pressurized air past said piston; force means to urge said piston toward said cylinder end; a shaft coaxial with said cylinder and attached to said piston at a first shaft end; and electrical switching means attached to said case, said switching means including first and second electrical contact means which are responsive to axial motions of said shaft to close said first electrical contact means when said piston reaches a low pressure piston position and close said second electrical contact means when said piston reaches a high pressure piston position; and electrical alerting means responsive to said switching means;
wherebya driver may be alerted to high or low pressure in the tire. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
-
Specification