Digital display tape measure with photoelectric sensing of tape displacement

A tape measure device for providing a digital readout corresponding to the actual cumulative extension of a tape, said tape measure device comprising:

• a housing,
• a flexible tape having an end thereof with two measuring scales extending along the length of said tape from said end in English units and metric units, respectively, with respective numbers printed on the tape along the respective scales for indicating the length along said tape from said end in English and metric units,
• means for winding said tape into a coil in said housing when the tape is retracted into the housing,
• two sets of optically sensed encoded markings extending along the tape, each set of markings corresponding to a respective one of said scales,
• a light source in said housing for illuminating said encoded markings on said tape as it is being extended from or retracted into said housing,
• light detector means in said housing and adjacent said tape for detecting an illuminated set of markings as they pass the light detector means during extension or retraction of said tape,
• manually operable control means for selectively shifting said lift detector means for detecting one or the other of said set of markings,
• electronic logic means responsive to the detected markings for providing an electronic count proportion to actual net longitudinal extension of said tape from said housing,
• a digital display for providing a display in response to said electronic count corresponding to the actual net extension of said tape from said housing,
• said set markings corresponding to the English scale include markings each having a longitudinal length along said tape proportional to a predetermined decimal portion of an inch,
• said set of markings corresponding to the metric scale include markings each having a longitudinal length along said tape proportional to a predetermined decimal portion of a centimeter,
• thereby providing a display of actual net extension of said tape from said housing in English or metric units, and
• thereby enabling the same electronic logic means to display the readout decimally in English units or in metric units as said manually operable control means is selectively actuated for detecting one or the other of said set of markings.

A tape measure device for providing a digital readout corresponding to the actual cumulative extension of a tape, said tape measure device comprising:

• a housing,
• a flexible tape having an end thereof with two measuring scales extending along the length of said tape from said end in English units and metric units, respectively, with respective numbers printed on the tape along the respective scales for indicating the length along said tape from said end in English and metric units,
• means for winding said tape into a coil in said housing when the tape is retracted into the housing,
• two sets of optically sensed encoded markings extending along the tape, each set of markings corresponding to a respective one of said scales,
• light source means in said housing for illuminating said encoded markings on said tape as it is being extended from or retracted into said housing,
• light detector means in said housing and adjacent said tape for detecting said illuminated markings as they pass the light detector means during extension or retraction of said tape,
• manually operable control means for selecting whether the readout is to be in English or metric units,
• electronic logic means responsive to the detected markings for providing an electronic count proportion to actual net longitudinal extension of said tape from said housing, and
• a digital display for providing a display in response to said electronic count corresponding to the actual net extension of said tape from said housing,
• thereby providing a display of actual net extension of said tape from said housing in English or metric units.

A tape measure device for providing a digital readout corresponding to the actual cumulative extension of a tape, said tape measure device comprising:

• a housing,
• a flexible tape having an end thereof with two measuring scales extending along the length of said tape from said end in English units and metric units, respectively, with respective numbers printed on the tape along the respective scales for indicating the length along said tape from said end in English and metric units,
• means for winding said tape into a coil in said housing when the tape is retracted into the housing,
• two sets of optically sensed encoded markings extending along the tape, each set of markings corresponding to a respective one of said scales,
• light source means in said housing for illuminating said encoded markings on said tape as it is being extended from or retracted into said housing,
• light detector means in said housing and adjacent said tape for detecting said illuminated markings as they pass the light detector means during extension or retraction of said tape,
• electronic logic means responsive to the detected markings for providing an electronic count proportion to actual net longitudinal extension of said tape from said housing,
• a digital display for providing a display in response to said electronic count corresponding to the actual net extension of said tape from said housing,
• manually operable control means for electing whether the readout is to be in English or metric units,
• said set markings corresponding to the English scale include markings each having a longitudinal length along said tape proportional to a predetermined decimal portion of an inch, and
• said set of markings corresponding to the metric scale including markings each having a longitudinal length along said tape proportional to a predetermined decimal portion of a centimeter,
• thereby enabling the same electronic logic means to display the readout decimally in English units or in metric units in response to said manually operable control means.

A tape measure device for providing a digital readout corresponding to the extension of a tape, said tape measure device comprising:

• a housing,
• a flexible tape, said tape having optically sensed encoded markings along its length,
• means for winding said tape into a coil in said housing,
• a light source in said housing for illuminating said markings on said tape as it is wound or unwound from said coil,
• light detector means in said housing and adjacent said tape for detecting said illuminated markings as they pass the light detector means during winding and unwinding,
• electronic logic means responsive to the detected markings for providing an electronic count proportional to longitudinal displacement of said tape past said light detector means,
• a digital display for providing a display corresponding to the displacement of said tape in response to said electronic count,
• said light detector means including two light detectors and at least two fiber optic bundles serving as light guides for directing light from said flexible tape to the respective detectors and further including fiber optic bundles for transmitting the light from said light source to said tape,
• said flexible tape having at least two separate sets of such markings, and
• said tape measure device further comprising means for selectively positioning said fiber optic bundles over one or the other of said sets of markings.

A tape measure device for providing a digital readout corresponding to the actual cumulative extension of a tape from its housing, said tape measure device comprising:

• a housing,
• a flexible tape, said tape having at least two measuring scales in different units of measure extending along the length thereof and also having at least two sets of encoded markings along its length, one set corresponding to one unit of measure and the other set corresponding to another unit of measure,
• means for winding said tape into a coil in said housing,
• detector means in said housing and adjacent said tape for selectively detecting one or the other of said two sets of markings as the markings pass the light detector means during extension of said tape from said housing and during retraction of said tape into said housing,
• electronic logic means responsive to the detection of a selected set of said encoded markings for providing an electronic count in measurement units proportional to actual cumulative longitudinal extension of said tape with the selected set of said encoded markings moving past said detector means, and
• a digital display for providing a measurement display corresponding to the actual cumulative extension of said tape in response to said electronic count.