Locks – Operating mechanism – Using a powered device
Reexamination Certificate
1999-03-26
2001-05-01
Barrett, Suzanne Dino (Department: 3627)
Locks
Operating mechanism
Using a powered device
C070S252000
Reexamination Certificate
active
06223571
ABSTRACT:
TECHNICAL FIELD
This invention relates generally to keystart switches, and more particularly to magnetically coupled keystart switches.
BACKGROUND ART
Keystart switches are used in operating machines of all types, such as automobiles, motorcycles, snowmobiles, trucks, and farm, construction and mining equipment. Many of these operating machines do not have an enclosed cab for protecting the operator and control panel from the environment. Instead, the operator and control panel are exposed to the environment. One component of the control panel that is particularly sensitive to environmental conditions is the keyswitch.
Conventional keyswitches typically have a lock cylinder and a housing. Upon insertion of an appropriate key, the lock cylinder is rotated, causing an electrical contact on the lock cylinder to make contact with an electrical contact on the housing. This closes a loop, forming a circuit that activates a function. Typical functions activated by a keyswitch in an operating machine are providing power to the accessories (such as lights, radio, power steering, etc.), or engaging the starter motor to crank the engine.
Environmental conditions, especially moisture, can cause abnormal operation of conventional keyswitches. Rain can penetrate the keyswitch and short-circuit the electrical contacts, causing the keyswitch to malfunction. A similar short-circuiting can also occur by other physical contaminants, such as some types of dust for example, entering the keyswitch.
One attempted solution to this problem is the use of seals around the exposed portions of the keyswitches. However, moisture and other contaminants can still enter the keyswitch via the keyhole. Further, the seals dry out and crack over time, allowing moisture and contaminants to enter through the cracks.
DISCLOSURE OF THE INVENTION
An apparatus and method for magnetically activating an output signal from a keyswitch. The keyswitch includes a housing, a magnetic sensing device, and a moveable body having a magnetic device that generates a magnetic field. The moveable body is disposed at least in part in the housing. The sensing device is disposed within the housing and physically isolated from the magnetic device. The sensing device detects a magnetic field of a predetermined magnitude and produces a flag signal as a function of detecting the magnetic field. The moveable body may receive a key having a first characteristic and rotate to cause the magnetic sensing device to detect the magnetic field from the magnetic device.
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Barrett Suzanne Dino
Caterpillar Inc.
Green Clifton G.
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