Communications: electrical – Land vehicle alarms or indicators – Internal alarm or indicator responsive to a condition of the...
Patent
1999-03-15
2000-09-26
Hofsass, Jeffery A.
Communications: electrical
Land vehicle alarms or indicators
Internal alarm or indicator responsive to a condition of the...
340442, 340443, 340626, 731462, 731465, 731468, B60C 2300
Patent
active
061247863
DESCRIPTION:
BRIEF SUMMARY
The present invention is based on an apparatus having the features recited in claim 1. An apparatus of this kind is known from WO 93/16891, and coacts with a "wheel electronics package," mounted on the respective wheel, which contains a pressure sensor, a circuit for processing the pressure measurement signal, a transmitter with transmission antenna, and a battery. The wheel electronics packages send their pressure measurement data to one or more reception antennas which are connected to a common control device in the body which contains a receiver, an analysis circuit, and a display unit. The wheel electronics packages send their signals at regular time intervals to the central control device, and draw from the battery, for which the longest possible operating life in the automobile (7 to 10 years) is desired, the energy required for operating the pressure sensor and the circuit which processes the pressure measurement signal, and for the transmitter. Achieving this service life requires on the one hand ensuring that the current consumption for operation of the wheel electronics packages is as low as possible. A particular problem arises from the fact that because of the way the wheel electronics package is installed on the wheel, in particular as an extension of the valve in the air space of the tire, the entire electronic unit, including the battery, should, for reasons relating to design and operating reliability, be hermetically encapsulated, preferably completely enveloped in a sealing compound. This means that after final installation of the wheel electronics package, the battery is connected to its loads and current is withdrawn from the battery in the stipulated pressure measurement and transmission cycles even if the wheel electronics package is not immediately put into service in the automobile but rather is initially stored, for example as a replacement part, in a warehouse, which can easily occur for one or two years. The subsequent service life in the automobile is therefore shortened by an amount equal to the storage time, which is undesirable.
It is the object of the present invention to indicate a way in which to counteract the shortening of the service life on the automobile of a hermetically encapsulated wheel electronics package of the kind cited initially.
In order to achieve this object, it might be envisioned to provide between the battery and the electrical loads of the wheel electronics package a switch which is open during the storage period of the wheel electronics package and is closed only when the wheel electronics package is used on the automobile (U.S. Pat. No. 4.734.674). Interfering with this, however, is the fact that the entire wheel electronics package is hermetically sealed, preventing any mechanical switch actuation from outside. Consideration might also be given to providing a reed switch or similar magnetically actuable switch which can be closed by bringing a powerful magnet into the vicinity of the housing of the wheel electronics package. A solution of this kind may be eliminated, however, because it lacks reliability: if the switch is open for a long period, insulating films, e.g. oxides and/or plastics from the surrounding material, may form on the contact surfaces, thus increasing the contact resistance so as to create the risk that any electrical connection made will be unreliable or indeed entirely absent. In addition, a switch, even a reed switch, contains at least one resilient contact element. When the automobile is driven, the wheel electronics package is exposed to severe vibration loads, which may lead to breakage of a contact element due to material fatigue. A switch also requires space in the wheel electronics package, which can be provided only with difficulty under the defined installation conditions. Switches can be miniaturized, but this does not achieve the object, since smaller contact elements have less mechanical load capacity, and miniaturization therefore inevitably results in unreliable operation. If what is desired for the battery is a se
REFERENCES:
patent: 3859628 (1975-01-01), Favini
patent: 4006326 (1977-02-01), Lejeune
patent: 4734674 (1988-03-01), Thomas et al.
patent: 4793277 (1988-12-01), Hass et al.
patent: 5285189 (1994-02-01), Nowiicki et al.
patent: 5559484 (1996-09-01), Nowicki et al.
patent: 5721374 (1998-02-01), Siekkinen et al.
Normann Norbert
Schulze Gunter Lothar
Uhl Gunter
Ami Doduco GmbH
Hofsass Jeffery A.
Nguyen Hung
LandOfFree
Device for controlling the tire pressure of automobiles by means does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Device for controlling the tire pressure of automobiles by means, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Device for controlling the tire pressure of automobiles by means will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2103549