Electricity: measuring and testing – Conductor identification or location – Inaccessible
Reexamination Certificate
1999-06-22
2001-07-10
Strecker, Gerard R. (Department: 2862)
Electricity: measuring and testing
Conductor identification or location
Inaccessible
C324S156000
Reexamination Certificate
active
06259241
ABSTRACT:
BACKGROUND
1. Field of Invention
The present invention relates to user displays in portable detector units, and in particular, to displays for indicating the location of a detected hidden object.
2. Related Art
Portable sensors, including handheld detector units, that are used to locate hidden objects are generally well known. U.S. Pat. Nos. 4,099,118 and 4,464,622, which are incorporated herein by reference, disclose detector units (e.g., “stud sensors” and alternating current detectors) that identify a hidden object's position behind, for example, a wall. Some detectors identify the hidden object by measuring a capacitance change in one or more sensor elements within the detector unit as the user moves the unit across the wall over the hidden object. Such objects include wooden structural studs, pipes, and other metal and nonmetal objects such as wiring.
Other well-known handheld detector units contain sensor element and detecting circuit combinations that measure electromagnetic field changes. Some of these detector types identify, for example, wires carrying alternating current. Others of these detector types identify, for example, objects that effect a local magnetic field, such as masses of metal or gas lines.
FIG. 1
illustrates a typical application in which a user holds a detector unit
10
against wall
12
. The user moves detector
10
transversely, as indicated by the arrows, to detect an object hidden from view behind wall
12
, such as framing stud
14
. Circuits within detector unit
10
display the sensed information on display
16
.
Handheld detector units typically display their sensed indications using a visual display, such as display
16
. Sensor visual displays include light-emitting diodes (LEDs) and liquid crystal displays (LCDs) in various configurations of one or more elements. For example, the National brand model number EZ380B (a Japanese manufactured product) includes a somewhat arrow-shaped LED display. Another detector sold under the name “Intellisensor,” made by The Stanley Works in New Britain, Conn., uses a vertical LED display. In addition, copending and commonly assigned U.S. patent application Ser. No. 09/134,157, filed Aug. 14, 1998 and incorporated herein by reference, and copending commonly assigned U.S. patent application Ser. No. 08/694,955 (U.S. Pat. No. 5,917,314, issued Jun. 29, 1999), filed Aug. 8, 1996 and incorporated herein by reference, disclose several LCD and LED display configurations. Detector unit visual displays are typically designed to assist the detector user in determining some characteristic of a sensed object, such as an edge or center. Referring again to
FIG. 1
, for example, display
16
may indicate stud
14
's edge
18
, a center position
20
located between edge
18
and edge
22
, both edges
18
and
22
, or other representations of stud
14
.
Handheld detector LED or LCD displays are typically mounted in the detector unit housing. Thus the display is displaced both laterally and in depth from the surface under which the detected object is located. Furthermore, users often operate handheld detectors at skewed angles and in unusual positions such as when searching for objects that are behind ceilings, floors, corners, etc. For example, in
FIG. 1
, if stud
14
is located behind a wall that is close to a large visual obstruction, such as a water heater tank, the user will have difficulty seeing display
16
. Even if display
16
is visible, the skewed viewing angle requires the user to make a visual angular estimate of the hidden object's location behind the wall's surface, based on the display's position in the detector unit housing. What is desired, therefore, is a way to improve the way detector information is displayed to the user.
SUMMARY
In accordance with the invention, a handheld detector projects a visible pattern onto the surface behind which a detected object is located. The projected pattern represents one or more predetermined characteristics of the detected object. The predetermined characteristic includes, but is not limited to, an edge, a position between two edges, a center position between two edges, a characteristic of the object's mass, or an electromagnetic characteristic emitted or affected by the object.
In one embodiment of the invention, a narrow aperture is defined in one end of the detector unit housing. When the detector unit's sensing circuit detects a hidden object, the sensing circuit signals an activating circuit that energizes a light source within the detector housing. A portion of the light from the light source passes through the aperture and thereby projects a line onto the surface beneath which the detected object is located.
In some embodiments, the detector unit includes two or more aperture and light source combinations to provide additional indications of the hidden object's position and orientation. In some embodiments, light is projected through one or more apertures in a single direction, while in other embodiments light is projected in opposite directions. And in some embodiments light is projected along two axes of the detector unit so as to indicate, for example, the intersection of two hidden objects. In still other embodiments, the user manually optionally displays light patterns on the concealing surface upon perceiving an alerting signal from the detector unit.
Some embodiments of the invention are combined with stud sensor circuits to make handheld “stud sensors” such as those used in the construction industry. However, the invention may be combined with other portable detector units designed for both indoor and outdoor use in detecting many different types of hidden or buried objects.
REFERENCES:
patent: 3805155 (1974-04-01), Tsuda et al.
patent: 4099118 (1978-07-01), Franklin et al.
patent: 4464622 (1984-08-01), Franklin
patent: 4536705 (1985-08-01), Hayes
patent: 5438265 (1995-08-01), Eslambolchi et al.
patent: 5917314 (1999-06-01), Heger et al.
patent: 2 188 432 (1987-09-01), None
Allenby Christopher B.
Klivans Norman R.
Skjerven Morrill & MacPherson LLP
Strecker Gerard R.
Zircon Corporation
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