Both commercially and domestically, it is oftentimes desirable if not absolutely necessary to be able to locate studs beneath sheet rocked walls or as structural support members for roofs and the like. For even the simple task of hanging a picture or installing a new set of shelves, the finding of a structural stud member behind a surface can be important if not critical.
Before there were stud finders, one would either pound a small nail into the wall until it hit a stud or a small pivoting magnet would be used whose orientation would change when a magnetizable object such as a nail was confronted.
Electronic stud finders replaced the hit and miss and pivotable magnet approaches. These products operate like a touch switch on a touch-sensitive lamp. They use changes in capacitance to sense stud location. When the plate inside the stud finder is over a surface such as wallboard, it will sense one dielectric constant but when over a stud, the dielectric constant is different. It works on a capacitance differential generated by density differences. The circuit in the stud finder can sense changes and report it on its display. The magnet approach was made the subject of U.S. Pat. No. 3,845,384 issued in 1974. The stud finder based upon detection of capacitive differences was made the subject of U.S. Pat. No. 4,099,118 issued in 1978.
Although current commercially available stud finders operate reasonably well in the right conditions, there are many instances where the detection of capacitive differences behind a wall or membrane can be difficult if not impossible For example, in applying the hardware necessary to support photovoltaic panels on a roof, it is oftentimes necessary to locate structural stud members for applying standoffs which in turn support rail members and solar photovoltaic panels thereon. Installations of this type have been disclosed in applicant's previously filed U.S. application Ser. No. 12/407,952, the disclosure of which is incorporated by reference herein. However, roofs oftentimes support one or more layers of composite shingles and similar waterproof membranes which provide surfaces which are too thick and uneven to enable capacitive-based stud finders to function.
It is thus an object of the present invention to provide a new paradigm in stud finder technology which does not depend upon capacitive differences to enable a user to locate a structural stud member beneath a surface.
It is yet a further object of the present invention to provide a novel stud finder device which can be used in virtually any environment whether or not the studs to be located are sufficiently proximate a homogeneous surface to enable them to be detected by capacitive techniques.
These and further objects will be more readily apparent when considering the following disclosure and appended claims.