Abstract:
A digital display tape measuring device is disclosed having a display screen exteriorly for displaying the measured distance. A tape having electrical conductivity capabilities and an insulator disposed longitudinally along the tape dividing the tape into two electrical conductors, and having a tip thereof electrically connecting both of the electrical conductors together such that an electrical circuit is formed with resistance that varies as the tape is extracted from device. An ohmmeter electrically coupled across the electrical circuit for measuring the circuit resistance. A microprocessor having inputs thereof coupled to outputs of the ohmmeter and having outputs coupled to said display screen. The microprocessor computes measurements made by as a function of the resistance measured by the ohmmeter.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
   This is a continuation of Provisional Application No. 60/347,854, filed Jan. 15, 2002 having the same title and by the same inventor hereof. 

   BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates generally to a tape measuring device and more particularly to a measuring device that will accurately and efficiently compute and display a measured length. 
   2. Background of the Invention 
   It can be seen that numerous devices have been developed to improve conventional measuring tape devices. For example, U.S. Pat. No. 5,691,923 issued to Adler, et al, discloses a digital measuring system primarily for use in the manufacturing industry that will automatically and electronically measure and record distances and dimensions and then transform these measured distance and dimensions into electrical signals. Included in the digital measuring system is a control and display unit which allow the user to manipulate and record the digital data received from the tape measuring device into a useful format. 
   Another example is seen in U.S. Pat. No. 5,433,014 issued to Falk, et al, which discloses a digital tape rule including a built-in radio transmitter for transmitting measurements to a remote location. A receiving unit is provided at the remote location for receiving, storing, and displaying the measurements. This device was designed for use in wood-frame construction to alleviate confusion when calling out measurements to the saw operator who cuts the lumber to a desired specification. 
   Yet another example is seen in U.S. Pat. No. 5,743,021 issued to Corcoran which discloses a digital length gauge with an optical encoder for providing a measurement of distance having an accuracy of about 0.01 mm. Housed within the digital length gauge is a metal tape with uniformly sized and spaced holes positioned along the center line of the tape. When the metal tape is extracted and retracted into the length gauge, the holes engage pins positioned on a sprocket, thus causing the sprocket to rotate. The rotation of the sprocket will cause an optical encoder to rotate along the same axis, thus producing optical pulses to provide the desired accuracy. 
   Although numerous devices have been developed to improve conventional tape measures, none of these previous efforts utilize resistance measurements for determining a specific length measurement, a Hall effect sensor for sensing pulses generated by magnets for calculating a specific distance, or utilize a pressure sensor for determining the pressure differential conclusively retrieving the specific distance. In addition, none of the prior art utilizes more than one means of determining a calculated measurement, thereby preventing a measurement verification method. 
   As will be seen, prior art techniques do not suggest the present inventive combination of component elements as disclosed and claimed herein by providing a tape measure device that is accurate and efficient in determining measurements. In addition, the present invention is compact in size, lightweight and is a device that is user friendly in that it inherently renders a unit that can be used by anyone regardless of age or dexterity. Accordingly, the present invention achieves its intended purposes, objectives and advantages over the prior art device through a new, useful and unobvious combination of component elements. 
   SUMMARY OF THE INVENTION 
   The present invention is a tape measure device designed and configured to accurately and efficiently record and determine a measured distance. In determining distance, the present invention utilizes three different methods that can be used independently or optionally, can be combined to provide for a unit that will have at least two means of determining distance. Accordingly, the present invention provides a unit that will include a checking system for the measured distance. 
   In order to provide for such a configuration, the present invention comprises a housing adapted to house and maintain a retractable tape that is wound around a reel. Exteriorly located on the housing is a display screen that will display the measured distance. 
   The tape includes a unique structure for enabling various embodiments to be utilized for determining the length of the particular measurement. Enabling such a configuration, the tape comprises an elongated flexible polymer casing having low stretch characteristics. Located exteriorly on a side of the tape are conventional visible graduations for representing a particular measurement. The use of visible indicia provides a means for the user to read and determine a particular measurement via the tape. 
   The casing for the tape is a circuit film that encloses a non-conductive liquid gel. This circuit film is a continuous member that extends the entire length of the tape. Located along the centerline of the tape is a wear surface that insulates the circuit film into two separate paths. This wear surface is adapted to contact a friction bearing. Thereby providing for the friction bearing to rotate on the wear surface as the tape is extracted from the housing. 
   In a first embodiment for determining a measured length, resistance measurement is utilized. In this configuration, as the strip is extracted from the housing, it passes through the friction bearings. This movement causes the bearings to rotate as the tape is extracted. The friction bearing applies pressure to the strip via the wear surfaces located on the upper and lower surface, forcing the liquid gel to the reel end of the tape strip. At the same time, the circuit film makes contact with the circuit film to complete an electrical circuit. Current is applied to the circuit film for enabling resistance to be measured. This measured resistance in the circuit is applied to a linear algorithm that computes the amount of tape extracted. The computed measurement is then displayed on the display screen. 
   In addition to providing a closed circuit, the friction bearing also provides for a differential in volume between the end of the tape to the friction bearing and from the friction bearing to the reel. The frictional bearing pinches on the casing forcing the area of contact of the wear surfaces to be free of liquid gel. This causes the excess gel to be displaced and thus provide for the differential in volume within the casing. Knowing the volume, which is measured via a pressure sensor, the distance is calibrated. 
   Still a further method for measuring distance is the use of magnets for sensing linear position. In order to allow for such a configuration a friction gear is provided. This gear is coupled to the friction bearing. As the tape is pulled from the housing, it passes through the friction bearing. This causes the bearing to rotate consequently causing the friction gear to rotate. Secured to the side of the friction gear is a plurality of magnets. Located above the friction gear is a linear magnetic sensor, such as a linear Hall Effect Sensor. The magnets form a magnetic field wherein as each magnet passes it is recognized by the linear sensor. After seizing rotation, the linear sensor can determine the distance traveled which is equal to the length of the measurement. 
   In use, at least one of the means of measurement is used by the tape measuring device of the present invention. In the preferred embodiment, at least two are utilized for providing an adequate and accurate means for determining a particular measurement. 
   Accordingly, it is the object of the present invention to provide for a tape measuring device that will overcome the deficiencies, shortcomings, and drawbacks of prior tape measuring devices and methods thereof. 
   Still another object of the present invention is to provide a tape-measuring device that during use will simultaneously enhance error checking in order to reduce the probability of user error, by providing at least one automatically measuring means. 
   Another object of the present invention, to be specifically enumerated herein, is to provide a tape measuring device in accordance with the preceding objects and one which will conform to conventional forms of manufacture, be of simple construction and easy to use so as to provide a device that is economically feasible, long lasting and relatively trouble free in operation. 
   Although there have been many inventions related to tape measuring devices, none of the inventions provide for multiple means for determining a particular measurement. Additionally, many of these prior inventions fail to be low cost and reliable enough to become commonly used. The present invention meets the requirements of the simplified design, compact size, low initial cost, low operating cost, ease of installation and maintainability, and minimal amount of training to successfully employ the invention. 
   The foregoing has outlined some of the more pertinent objects of the invention. These objects should be construed to be merely illustrative of some of the more prominent features of the application of the intended invention. Many other beneficial results may be obtained by applying the disclosed invention in a different manner or modifying the invention within the scope of the disclosure. Accordingly, a fuller understanding of the invention may be had by referring to the detailed description of the preferred embodiments in addition to the scope of the invention defined by the claims taken in conjunction with the accompanying drawings. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a cross-sectional view of the housing unit illustrating the components used with the digital display measure device of the present invention. 
       FIG. 2  is a top view of the housing unit used with the digital display-measuring device of the present invention. 
       FIG. 3   a  is a top view of the first embodiment of the tape used in the digital display measure device of the present invention. 
       FIG. 3   b  is a cross-sectional view of the first embodiment of the tape used in the digital display measure device of the present invention. 
       FIG. 4   a  is a top view of the second embodiment of the tape used in the digital display measure device of the present invention. 
       FIG. 4   b  is a cross-sectional view of the second embodiment of the tape used in the digital display measure device of the present invention. 
       FIG. 5   a  is a top view of the third embodiment of the tape used in the digital display measure device of the present invention. 
       FIG. 5   b  is a cross-sectional view of the third embodiment of the tape used in the digital display measure device of the present invention. 
       FIG. 6   a  is a side view of an alternative embodiment for measurement used with the digital display measure device of the present invention. 
       FIG. 6   b  is a cross-sectional view of an enlarged view of the pressure chamber used with the alternative measurement device shown in  FIG. 6   a  that is utilized for the digital display measuring device of the present invention. 
       FIG. 7  is an end view of the tape used with the digital display measure device of the present invention. 
       FIG. 8  is a cross-sectional view of an alternative embodiment for measurement used with the digital display measure device of the present invention. 
   

   Similar reference numerals refer to similar parts throughout the several views of the drawings. 
   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   With reference to the drawings, in particular to  FIGS. 1-8  thereof, the present invention; a digital display-measuring device, generally denoted by reference numeral  10  will be described. The purpose of the present invention is to provide for a tape measuring device designed and configured to accurately and efficiently record and determine a measured distance. 
   In order to provide for such a configuration, the present invention  10 , as seen in  FIGS. 1 and 2 , comprises a housing  12  adapted to house and maintain a retractable tape  14  that is wound around a reel  16 . Exteriorly located on the housing is a display screen  18  that will display the measured distance. Operating the unit is done via the use of a plurality of function buttons  20 . The function buttons  20  will enable a plurality of functions to occur as desired, such as, but not limited to storing the measured distance, converting the distance from metric to English measurements, converting from English to metric, or the like. 
   To allow for computing or storage to take place, the present invention includes a microprocessor  22  located therein. This microprocessor is coupled to the function buttons  20  and to a power source  24   a  or  24   b.  Moreover, the function buttons  20  may be used as data entry when the microprocessor is used as a calculator. The microprocessor  22  also receives input signals from sensors described hereinbelow in order to compute the distances measured with the tape  14 . The power source may be conventional batteries  24   a,  solar cell  24   b  or the like. The microprocessor will determine the distance from data supplied thereto and feed the computed distance to the display  18 . Using the function buttons, the user can store, retrieve, calculate or display any particular measurement. 
   The measuring system of the present invention will provide for the tape  14  to include a unique structure for enabling various embodiments to be utilized for determining the length of the particular measurement. Enabling for such a configuration, the tape  14  comprises an elongated flexible polymer casing  28  having low stretch characteristics. This tape is seen in  FIGS. 3   a  through  6   b.  As seen, the tape includes an upper surface  30   a  and a lower surface  30   b  to provide for a hollow interior. The tip or start of the tape is physically and ohmically coupled together. Located exteriorly on a side of the tape are conventional visible graduations for representing a particular measurement. The use of these visible graduations provides a manual means for the user to read and determine a particular measurement via the tape in the usual manner. 
   Located within the casing of the tape on the upper surface and the lower surface is a circuit film  32  that surrounds a non-conductive liquid gel  34 . This circuit film is a continuous member that extends the entire length of the tape and thus will provide for a film to be located above and below the non-conductive liquid gel  34 . Located above the circuit film  32  and on the upper surface and lower surface of the casing is at least one wear surface  44 , which is also an electrical insulator. This wear surface on the upper and lower surfaces is adapted to contact a friction bearing  36  (illustrated in FIG.  1 ). The friction bearing rotates on the wear surface as the tape is extracted from the housing. This wear surface is also known as the friction bearing surface  40 . 
   In a first embodiment for determining a measured length, resistance measurement is utilized. In this configuration, as the tape  14  is extracted from the housing  12 , it passes through the friction bearing  36 . This movement causes the bearings to rotate as the tape is extracted. The friction bearing applies pressure to the strip via the wear surfaces located on the upper and lower surface of the tape, thereby forcing the liquid gel to the reel end of the tape strip. At the same time, the circuit film located in proximity to the upper and lower surfaces  30   a  and  30   b  make ohmic contact at the point of the bearing. The tip of the tape is coupled together, as seen in  FIG. 7 , and the tape is isolated electrically between the two sides thereof by the insulating bearing surface  44 . The bearings  36  make electrical contact with each side of the film, wherein a complete electrical circuit is consequently formed. That is, the electrical circuit includes one side of the bearing  36  making ohmic contact with the tape surface, the stretch of tape extending to the tip thereof, back along the stretch of tape (on the other side opposite the bearing surface  44 ) to a second side of the bearing  36 , which is electrically insulated from the first side thereof. An ohmmeter  80  ( FIG. 8 ) is coupled across the bearings  36  for making ohmic contact with each of end of the circuit. Once the closed circuit is formed, the ohmmeter  80  provides a readout to the microprocessor  22  which computes the distance measured as a function of the resistance measured in the circuit. This measured resistance in the circuit is applied to a linear algorithm programmed in the microprocessor  22 , which computes the amount of tape extracted. The computed measurement, calculated via the microprocessor, is displayed on the display screen  18 . 
   In addition to providing a closed circuit, the friction bearing  36  also provides for a differential in volume between the end of the tape to the friction bearing and from the friction bearing to the reel. The friction bearing  36  pinches on the casing (upper surface  30   a  and lower surface  30   b  of the film) forcing the area of contact of the wear surfaces to be free of liquid gel  34 . The pinching action may be seen in the cross-sectional view of FIG.  8 . This pinching action causes the gel in the tape  14  to be squeezed back into the reel side of the device  10 . Accordingly, the pressure of the gel (which increases as the tape is extracted) may be measured within the casing. Knowing the beginning pressure (i.e., pressure when the tape is fully coiled up), and comparing it with the pressure when the tape is extended via a pressure sensor  38 , the distance may be calculated. A linear relationship exists between the pressure of the gel and the distance the tape  14  is extended. Accordingly, the microprocessor can compute the distance measured as a function of the measured gel pressure. As seen in  FIGS. 6   a  and  6   b,  the tape reel  16  is maintained on a reel bearing  42 . The sensors are located in proximity to the reel bearings  42 . These sensors  38  measure the pressure of the gel that is located within the tape from the point at which contact is made at the friction bearing  34  to the tape reel. Sensing the difference in pressure a distance is calculated by the microprocessor and displayed the screen  18 . 
   The methods defined above utilize a tape that may include a varied number of embodiments. The embodiments are illustrated in  FIGS. 3   a - 5   b.  As seen, the friction bearing surface  40  can be centrally located on the tape  14 , as seen in  FIGS. 3   a - 4   b.  In this design, the circuit film would be located on either side of the wear surface  40 . In an alternative embodiment, the wear surface  40  can be located on opposite sides of the length of the film. Optionally, and preferably, the bearing surface  40  would extend the entire horizontal length of the film and thus when contact is made it will prevent any gel from extending across the location of the bearing. In addition, apertures or perforations  44  can extend therethrough and can be a means of marking the item measured. Thereby providing for a pencil, pen or the like to be adapted to be inserted into the aperture for marking the particular item measured. 
   To further assist the user, the end  46  of the tape  14 , as seen in  FIG. 7 , can include an anchoring device  48  for enabling the end to be secured to a particular surface. In addition, an additional aperture or the like, illustrated, but not labeled can extend through the end of the tape so as to provide for an additional means of anchoring. 
   Another method may be provided for measuring distance. This added method employs magnets wherein the magnets are used for sensing linear position. In order to allow for such a configuration, as seen in  FIG. 8 , a friction gear  50  is provided. This gear  50  is coupled to the friction bearing  36 . As the tape is pulled from the housing, it passes through the friction bearing  36 . This causes the bearing  36  to rotate consequently causing the friction gear  50  to rotate. To aid in the rotation, teeth may be located on the friction gear and the bearing. The teeth, if provided on the bearing  36  is used, it can be interlockable with perforations  44  that are provided on the tape  14 . 
   Secured to the side of the friction gear is a plurality of magnets  52 . Located above the friction gear  50  is a linear magnetic sensor  54 , such as a linear Hall Effect Sensor. The magnets form a magnet field and as each magnet passes it is recognized by the linear sensor. After seizing rotation, the linear sensor can determine the distance traveled which is equal to the length of the measurement. 
   In use, at least one of the means of measurement is used for the tape measuring device of the present invention. In the preferred embodiment, at least two are utilized for providing an adequate and accurate means for determining a particular measurement. 
   Other features may be added for enhancing the utility of the present invention. These features include providing the tape strip with a synthetic optical fiber  56  that can be located on the outer ends of the tape. This will provide for added illumination for inherently providing an increase in visibility of the tape when in use. As seen in  FIG. 1 , the housing can be equipped with a hanging mechanism  58  that enables the present invention to be hung on a nail or the like. A bubble level  60  can also be provided so as to render for a multi-purpose tape measure device. This bubble level will allow for the present invention to act as a level. A writing implement holding element  62  may also be provided. In addition, a laser pointer  64  can be attached to the housing. 
   The housing may also be configured so as to have an end that is pivotally secured. This will provide for a unit that may be utilized even in awkward positions. To provide for such a configuration, as seen in  FIG. 1 , the front end  66  is pivotally secured via a conventional pivot mechanism  68  to the rear of the housing  12 . This will provide for a slit or opening to be located on the end wall  70  of the rear of the housing and a corresponding opening to be located on the end wall  72  of the front end  66 . Thus, each side includes a wall. The opening will provide for the tape to extend therethrough. 
   While the present invention has been particularly shown and described with reference to an embodiment thereof, it will be understood by those skilled in the art that various changes in form and detail may be made without departing from the spirit and scope of the present invention.