Inflation pressure indicator for vehicle tires
First Claim
1. An inflation indicator for pneumatic tires for vehicles, said indicator including:
- a body mountable on a wheel fitted with a tire;
an axial bore in the body adapted to communicate with the interior of the tire;
a piston means slidably mounted in the axial bore;
sealing means between the piston means and the axial bore;
compression means in the body acting on the piston means in opposition to the inflation pressure in the tire;
datum means in or on a substantially transparent portion of the body; and
visual indicator means on the piston means, so arranged that at a preselected cold inflation pressure of the tire, the piston means will be moved against the compression means to a position where the visual indicator means is adjacent the datum means;
characterized in that;
as the inflation pressure in the tire increases due to heat generated in the tire, the increased inflation pressure moving the piston means against the compression means, the heat transmitted to the body causes a portion of the body between the wheel and the datum means to increase in length in an axial direction, but without any increase in the diameter of the axial bore so that the visual indicator means remains adjacent the datum means to indicate the cold inflation pressure of the tire, the body acting as a temperature compensator for the increase hot inflation pressure in the tire relative to the cold inflation measure.
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Accused Products
Abstract
An inflation pressure indicator (100) for pneumatic tires for vehicles has a body (101) mountable on a wheel rim (149) to which a tire is fitted. A piston (122) is slidably mounted in a bore (102) in the body (101), and, at a preselected pressure, moves in the bore (102) against the compression spring (125) to a position adjacent a datum line (136) on the body (101). A tire valve (130) is fitted to the piston (122) to enable the tire to be inflated or deflated, when an air hose fitting is connected to the body (101). By selective injection moulding of the body (101) from polycarbonate, the length of the body (101) will increase with increased heat so that the indicator (100) will correctly indicate the cold tire pressure when the tire is hot.
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Citations
10 Claims
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1. An inflation indicator for pneumatic tires for vehicles, said indicator including:
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a body mountable on a wheel fitted with a tire; an axial bore in the body adapted to communicate with the interior of the tire; a piston means slidably mounted in the axial bore; sealing means between the piston means and the axial bore; compression means in the body acting on the piston means in opposition to the inflation pressure in the tire; datum means in or on a substantially transparent portion of the body; and visual indicator means on the piston means, so arranged that at a preselected cold inflation pressure of the tire, the piston means will be moved against the compression means to a position where the visual indicator means is adjacent the datum means;
characterized in that;as the inflation pressure in the tire increases due to heat generated in the tire, the increased inflation pressure moving the piston means against the compression means, the heat transmitted to the body causes a portion of the body between the wheel and the datum means to increase in length in an axial direction, but without any increase in the diameter of the axial bore so that the visual indicator means remains adjacent the datum means to indicate the cold inflation pressure of the tire, the body acting as a temperature compensator for the increase hot inflation pressure in the tire relative to the cold inflation measure. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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Specification