Attachment mechanism for a tire monitoring system

A tire pressure monitoring apparatus, for mounting on a vehicle wheel that is configured to have a tire mounted thereon and that has a first opening, includes a tire monitor for sensing pressure in the tire. The tire monitor includes a housing having a spherical surface and a second opening that extends through the spherical surface. A tire valve stem is configured to extend through the first and second openings, and the valve stem has a threaded portion. The apparatus further includes a threaded fastener that is engageable with the threaded portion of the valve stem for attaching together the tire monitor and the valve stem. The fastener has a spherical surface that is engageable with the spherical surface of the housing when the fastener is engaged with the threaded portion of the valve stem.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to an attachment mechanism for a tire monitoring system.

2. Background Art

Tire monitoring systems are designed to monitor a tire parameter, such as tire pressure, and may be configured to be attached to a vehicle wheel. Examples of prior attachment mechanisms for use with tire monitoring systems are disclosed in U.S. Pat. Nos. 5,844,131 and 6,055,855.

SUMMARY OF THE INVENTION

Under the invention, a tire monitoring apparatus is provided for mounting on a vehicle wheel that is configured to have a tire mounted thereon, wherein the wheel has a first opening. The apparatus includes a tire monitor for monitoring a tire parameter. The tire monitor includes a housing having a spherical surface and a second opening that extends through the spherical surface. A tire valve stem is configured to extend through the first and second openings, and the valve stem has a threaded portion. The apparatus further includes a threaded fastener that is engageable with the threaded portion of the valve stem for attaching together the tire monitor and the valve stem. The fastener has a spherical surface that is engageable with the spherical surface of the housing when the fastener is engaged with the threaded portion of the valve stem.

Further under the invention, a tire monitoring apparatus is provided for mounting on a vehicle wheel that is configured to have a tire mounted thereon, wherein the wheel has a first opening. The apparatus includes a tire monitor for sensing pressure in the tire. The tire monitor includes a housing having a spherical surface and a second opening that extends through the spherical surface. A tire inflator valve assembly is configured to extend through the first and second openings, and the valve assembly has a longitudinal axis and a threaded portion. The apparatus further includes a threaded fastener that is engageable with the threaded portion of the valve assembly for attaching together the tire monitor and the valve assembly. The fastener includes a base portion having first and second ends. The fastener further includes multiple spaced apart first projections extending from the first end of the base portion, and multiple spaced apart second projections extending from the second end of the base portion. Each projection has a spherical surface. The spherical surfaces of the first projections are configured to provide at least three first points of contact with the spherical surface of the housing when the first end of the base portion of the fastener is facing toward the spherical surface of the housing and the fastener is engaged with the threaded portion of the valve assembly, such that the first points of contact lie generally in a plane that is perpendicular to the axis of the valve assembly. The spherical surfaces of the second projections are configured to provide at least three second points of contact with the spherical surface of the housing when the second end of the base portion of the fastener is facing toward the spherical surface of the housing and the fastener is engaged with the threaded portion of the valve assembly, such that the second points of contact lie generally in a plane that is perpendicular to the axis of the valve assembly.

Still further under the invention, a tire monitoring apparatus is provided for mounting on a vehicle wheel that is configured to have a tire mounted thereon, wherein the wheel has a first opening. The apparatus includes a tire monitor for monitoring a tire parameter, and the tire monitor includes a housing having a spherical surface and a second opening that extends through the spherical surface. A tire valve stem is configured to extend through the first and second openings, and the valve stem has a threaded portion. The apparatus further includes a threaded fastener that is engageable with the threaded portion of the valve stem and the spherical surface of the housing for attaching together the tire monitor and the valve stem. The fastener has a configuration that provides at least three points of contact with the spherical surface of the housing when the fastener is engaged with the spherical surface of the housing.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT(S)

FIG. 1shows a tire monitoring system or apparatus10according to the invention mounted on a vehicle wheel12that is configured to have a tire14mounted thereon. The apparatus10is configured to extend through a first opening16in the wheel12, and includes a tire monitor18for monitoring a tire paramater, a tire inflator valve assembly20attached to the tire monitor18, and a threaded fastener21engaged with the valve assembly20for attaching together the tire monitor18and the valve assembly20.

The tire monitor18includes one or more monitoring devices, such as one or more sensors22, for monitoring one or more tire parameters, such as tire pressure, temperature, location, status (i.e., whether or not the tire14is in motion) and/or speed. The tire monitor18may also include one or more transmitters23in communication with the sensors22for transmitting data signals representing information concerning the one or more tire parameters to a receiver (not shown).

For example, the tire monitor18may be configured to sense pressure in the tire14, and provide a signal that is indicative of the sensed pressure to the receiver. If the air pressure in the tire14reduces below a predetermined threshold, the tire monitor18may provide a signal to the receiver that actuates an alarm, such as a light on a vehicle instrument panel, to apprise a vehicle occupant of the pressure reduction.

The tire monitor18includes a housing24for receiving the electronic circuitry or other sensing means. The housing24defines a pocket25for receiving a portion of the valve assembly20and the fastener21. The housing24further includes a spherical surface26and a second opening28, such as an elongated slot, that extends through the spherical surface26.

The valve assembly20includes a valve stem30having a longitudinal axis32and a passage34through which air may travel. The valve stem30further includes first, second and third threaded portions36,38and40, respectively, and a spherical surface42.

The valve assembly20further includes a valve44disposed in the passage34of the valve stem30, and a dust cap46that is engageable with the first threaded portion36. The valve44is configured to allow air to pass into the tire14, while inhibiting leakage through the passage34from the tire14.

The fastener21is engageable with the third threaded portion40of the valve stem30for attaching together the tire monitor18and the valve stem30. In one embodiment of the invention, the fastener21is configured to provide at least three points of contact with the spherical surface26of the housing24when the fastener21is engaged with the third threaded portion40of the valve stem30.

While the fastener21may have any suitable configuration, in the embodiment shown inFIGS. 1-3, the fastener21includes a threaded base portion48that is engageable with the third threaded portion40of the valve stem30. The base portion48has an axis49that is generally coincident with the axis32of the valve stem30when the fastener21is engaged with the valve stem30.

In the embodiment shown in the Figures, the base portion48has a generally rectangular shape, such as a square shape, with generally flat sides. Furthermore, the sides of the base portion48are engageable with walls of the pocket25such that rotation of the fastener21is inhibited when the fastener21is engaged with the valve stem30.

Referring toFIG. 3, the fastener21further includes multiple first engaging members, such as multiple spaced apart first projections50, that extend from a first end52of the base portion48, and multiple second engaging members, such as multiple spaced apart second projections54, that extend from a second end56of the base portion48. With such a configuration, the fastener21may be positioned with either end52or56facing toward the spherical surface26of the housing24, such that either the first projections50or the second projections54engage the spherical surface26.

In the embodiment shown inFIG. 3, each projection50and54has an engaging surface, such as a spherical surface58, that is engageable with the spherical surface26of the housing24. The spherical surfaces58of the first projections50cooperate to provide multiple first points of contact, such as at least three first points of contact, with the spherical surface26when the first end52of the base portion48is facing toward the spherical surface26and the fastener21is engaged with the third threaded portion40of the valve stem30. Although the fastener21is shown with four first projections50that may each provide a first point of contact such that the fastener21may provide four first points of contact with the spherical surface26, it may be that only three of the first projections50are able to contact the spherical surface26at any one time, due to manufacturing tolerances and/or other factors. Furthermore, referring toFIG. 3, the fastener21may be configured such the first points of contact lie generally in a plane60that is generally perpendicular to the axis32of the valve stem30and the axis49of the fastener21when the first projections50are engaged with the spherical surface26of the housing24.

Similarly, the spherical surfaces58of the second projections54are configured to provide multiple second points of contact, such as at least three second points of contact, with the spherical surface26of the housing24when the second end56of the base portion48is facing toward the spherical surface26and the fastener21is engaged with the third threaded portion40of the valve stem30. Although the fastener21is shown with four second projections54that may each provide a second point of contact such that the fastener21may provide four second points of contact with the spherical surface26, it may be that only three of the second projections54are able to contact the spherical surface26at any one time, due to manufacturing tolerances and/or other factors. Furthermore, the fastener21may be configured such the second points of contact lie generally in a plane that is generally perpendicular to the axis32of the valve stem30and the axis49of the fastener21when the second projections54are engaged with the spherical surface26of the housing24.

Alternatively, each projection50and54may include an engaging surface having any suitable configuration for engaging the spherical surface26to provide contact, such as a point of contact, between the projection50,54and the spherical surface26. For example, referring toFIG. 4, each projection50and54may have a concical surface58′ (only one first projection50is shown in FIG.4), or other concave surface. As another example, referring toFIG. 5, each projection50and54may have a generally flat, sloped surface58″ (only one first projection50is shown in FIG.5). As yet another example, each projection50and54may have a convex surface.

Returning toFIG. 1, the apparatus10may further include an additional fastener, such as threaded nut62, that is engageable with the second threaded portion38of the valve stem30and the wheel12. In the embodiment shown inFIG. 1, the nut62functions to secure the valve stem30to the wheel12. A seal64may also be positioned between the wheel12and the valve stem30to inhibit passage of air around the valve stem30.

The apparatus10may be assembled together and mounted on the wheel12in any suitable manner. For example, referring toFIG. 1, the third threaded portion40of the valve stem30may be inserted through the second opening28of the housing24, and the fastener21may be positioned on the third threaded portion40. Next, the valve stem30may be rotated to thread the third threaded portion40through the fastener21. Referring toFIG. 2, the sides of the base portion48of the fastener21may engage walls of the pocket25of the housing24such that rotation, of the fastener21is inhibited when the valve stem30is rotated.

Next, the seal64may be positioned around the valve stem30, and the valve stem30may then be inserted into the first opening16of the wheel12such that the first and second threaded portions36and38, respectively, extend beyond an exterior surface of the wheel12. Advantageously, the angular orientation of the valve stem30may be adjusted with respect to the housing24so that the valve assembly20and housing24may conform to various wheel configurations. For example, the valve stem30may be pivoted with respect to the housing24such that the end of the valve stem30disposed outside of the wheel12may move upwardly or downwardly with respect to the position shown in FIG.1. Once a desired orientation is achieved, the valve stem30may be rotated to tighten the fastener21against the spherical surface26to thereby fixedly secure together the tire monitor18and the valve assembly20. The nut62may then be threaded onto the second threaded portion38of the valve stem30to secure tire monitor18and valve assembly20to the wheel12.

As another example, the valve stem30may be inserted into the first opening16of the wheel12prior to attaching the tire monitor18to the valve stem30. Next, the tire monitor18may be attached to the valve stem30using the fastener21, and the nut62may be attached to the valve stem30to secure the apparatus10to the wheel12.

With the configuration of the fastener21described above, the fastener21may be positioned on the valve stem30such that either end52or56faces toward the spherical surface26. Furthermore, the fastener21may provide at least three points of contact with the spherical surface26regardless of the angular orientation of the valve stem30relative to the housing24. Moreover, the points of contact may lie in a plane that is generally perpendicular to the axis49of the fastener21such that the fastener21functions to align the axes32and49when the fastener21is engaged with the spherical surface26.