Real Estate Electro Tape

The instant inventions relates, generally, to the field of measurement instruments, and, more specifically, to devices that measure the length of an interior or exterior wall by indirect optical means.

In many fields of endeavor, such as real estate appraisal, architecture, engineering, and building inspection, it is necessary to measure the length of an interior or exterior wall. It is often difficult to get close enough to the wall to use, for instance, a measuring tape due to obstructions, vegetation, or jags in the direction of the wall.

A number of measuring solutions have been suggested. M. Fox (U.S. Pat. 3,908,281) suggests a real estate appraisal instrument and method. However, this instrument requires that an object of known dimension be observed and such an object is not always available. R. Genho (U.S. Pat. 3,897,637) proposes a laser level and square that does not provide any measuring means but merely provides a laser-generated line that defines a level. J. Rando (U.S. Pat. 5,287,627) provides an automatic plumb and level tool with acoustic measuring capability. This device is very useful in providing a means for measuring the distance to a laser-illuminated object but does not provide means for measuring the length of the object itself.

It is, therefore, a primary object of the present invention to provide a real estate electro tape that can be used to measure the length of an interior or exterior wall without direct contact with the wall.

A further object is to provide a real estate electro tape which uses optical methods to measure the length of an interior or exterior wall.

Another object is to provide a real estate electro tape which measures the length of an interior or exterior wall with a fairly high degree of accuracy.

A further object is to provide a real estate electro tape which measures the length of an interior or exterior wall quickly and with little training.

A further object is to provide a real estate electro tape which is simple and inexpensive to fabricate.

A yet further object is to provide a real estate electro tape that has an easy to read display.

To the accomplishment of the above and related objects, this invention may be embodied in the form illustrated in the accompanying drawings, attention being called to the fact, however, that the drawings are illustrative only and that changes may be made in the specific construction illustrated and described within the scope of the appended claims.

The figures in the drawings are briefly described as follows:

FIG. 1 is a diagrammatic view of the invention shown in use measuring the length of a wall.

FIG. 2 illustrates the algorithm used by the invention.

FIG. 3 is a front view of the invention.

FIG. 4 is a top view of the invention showing the controls and display thereof.

FIG. 5 is an electronic block diagram of the invention.

FIG. 1 illustrates the real estate electro tape 10 in actual use. The wall to be measured is numeral 17. In use, a sonic tape 16 is aimed at wall 17 to establish the distance between the invention 10 and the wall 17. Sonic tape 16 is a conventional technology already in use and available from various sources. The output of the sonic tape 16 is the perpendicular distance (H) from the wall 17. Next, steerable laser 12 is aimed at one corner of the wall. The user can confirm that the laser is hitting the edge or corner of the wall by observing the reflection of the laser. The beam from 12 makes an angle (.theta..sub.2) with the perpendicular. Similarly, steerable laser 14 is aimed at the opposite wall edge or corner to determine angle (.theta..sub.1). Note that .theta..sub.1 and .theta..sub.2 are typically not equal. Since the steerable lasers 12 and 14 are not exactly coincident with the sonic tape 16, the displacement L' from sonic tape 16 must be taken into consideration. The total length of the wall 17 is determined, then, according to the following formula (see FIG. 2):

The physical layout of the invention can best be understood with reference to FIGS. 3 and 4. Sonic tape 16 is centrally mounted on the front of 10. Steerable lasers 12 and 14 are mounted at equal distances from sonic tape 16 and are mounted so as to allow the beams to scan in the horizontal plane. Laser steering knob/potentiometer 18 is used to adjust the horizontal position of steerable laser 14 and laser steering knob/potentiometer 20 is used to adjust the horizontal position of steerable laser 12. The steering knobs are locked and released using laser locking/release buttons 22 and 30. Power to 10 is turned on and off using on/off power switch 26. When the distance measurement is desired, calculate button 28 is depressed causing information to be shown on display 24.

The electronic operation of the invention is best understood with reference to FIG. 5. Microprocessor 34 processes data from a number of sources according to algorithm 32. The inputs include: the output .theta..sub.1 of laser steering knob/potentiometer 18, the output .theta..sub.2 of laser steering knob/potentiometer 20, and the output H of sonic tape 16. The output of microprocessor 34 is input to display 24, which is typically a liquid crystal display (LCD) or a light emitting diode display (LED). The information displayed includes L.sub.T and, optionally H, .theta..sub.1, and .theta..sub.2.

While certain novel features of this invention have been shown and described and are pointed out in the annexed claims, it will be understood that various omissions, substitutions and changes in the forms and the details of the device illustrated and in its operation can be made by those skilled in the art without departing from the spirit of the invention.