Abstract:
The tape measure incorporates a lighting device that is positioned to illuminate a measured length on the tape. The tape has a set of numerals for outside measurement that are of one color and a set of numerals for inside measurement that are of a different color. When switched on, the light provides a significant contrast with one of the sets of numerals to make that particular set of numerals significantly stand out from the other set of numerals.

Description:
FIELD OF THE INVENTION 
   This invention relates to coiled steel tape measures. More particularly this invention relates to an improved tape measure for making internal measurements between generally parallel members. This invention also discloses a design for improved gripping while clipped on a belt. 
   BACKGROUND OF THE INVENTION 
   Taking an internal measurement, say for example, measuring the exact width of a room between two walls is problematic. First it is necessary to maintain the outside portion of the hook on the tape against one of the two walls while the tape is extended. To prevent the tape from bending under the force of gravity it is necessary that the tape and the tape measure be maintained in an upright position. Then it is necessary, while holding the back of the housing of the tape measure against the other of the walls to read the tape measure. Typically a tape measure has a lateral slot which is about ¼ inch high through which the tape is pulled from the housing. One must read the measurement lines and numerals on the tape where it begins to project from the housing. Because the housing is about ¼ inch above the tape one should align their eye on a line projected along a front side wall of the housing which is perpendicular to the tape to avoid parallax and thereby obtain an accurate reading. The problem with doing this is that it is impossible to position one&#39;s eye perpendicular to the tape above where the tape projects from the housing when the tape measure is adjacent to the wall. One solution is to extend the tape around a corner on the adjacent wall, and then read the tape at a midpoint in the arc where the tape bends around the corner. But to do this with a reasonable degree of accurately one must ensure that they read the tape when there eye is on a line which projects perpendicularly from a midpoint of the tape bending around the corner. This is time consuming and problematic. 
   Some tape measures are numerated to allow one to read both outside and inside measurements. The set of numerals for inside measures includes the extended length of the tape plus and additional few inches for the length of the housing on the tape measure when the back thereof is held against the other wall. This simplifies having to add this additional length onto the measured projection of the tape from the housing. But the problem with this is that when measuring a longer length, one may inadvertently read from the wrong set of numerals. One solution to this is to place one set of numerals on the convex side of the tape. But these are subject to excessive wear when the tape moves in and out of the housing. Another problem is that it is just as difficult to read the underside of the tape accurately, especially when the tape measure is positioned adjacent to the other wall. What is needed is a way to so clearly distinguish between the sets of numerals so that they could not inadvertently be mistake even at the end of a long day when a user is not alert. 
   Yet another problem is that tape measures are too easily brushed off a user when clipped on a belt. If a tape measure is brushed off and falls on a hard surface, or from a ladder, it is likely to be damaged. 
   OBJECTS OF THE INVENTION 
   It is an object of this invention to disclose improvements in a tape measure which allow a user to more readily and accurately use and read the tape. It is an object of this invention to disclose a tape measure which facilitates taking inside measurements. One improvement disclosed utilises a has high friction outer hook end portion. It is yet a further object of this invention to disclose a tape measure which has a second scale positioned on its concave side which and which utilises a colored light emitting diode and a scale having a contrasting color to the light to differentiate that scale when making inside measurements. It is yet another object of this invention to disclose a tape measure which uses a focused light to overcome reading error arising from parallax. It is a final object of this invention to disclose improvements to a tape measure which will prevent unintended disengagement when the tape measure is clipped on a belt. 
   One aspect of this invention provides for an improved tape measure for making an internal measurement from a member of the type having a tape coiled in a housing having a tape hook external to the housing on an unattached end portion of the tape, and measurement lines and numerals on a concave side portion of the tape which increment from the hook and which can be read when the hook is pulled from the housing, wherein the improvement comprises: a non slip means positioned along an outside face portion of the hook so that when the outside of the hook is pressed against one member the hook will be less inclined to slip therealong. 
   In a preferred aspect the above tape measure further comprises a belt clip having a downwardly extending arm attached to a broad side of the housing and a soft plastic gripping pad positioned on one of the belt clip arm and the broad side of the housing adjacent to the arm to provide better adhesion when the belt clip is engaged on a worn belt. 
   Various other objects, advantages and features of this invention will become apparent to those skilled in the art from the following description in conjunction with the accompanying drawings. 

   
     FIGURES OF THE INVENTION 
       FIG. 1  is a perspective view of a tape measure having the following improvements thereon comprising the invention herein. Generally these improvements are a roughened surface on an outside end portion of the hook on an end portion of the tape, a light to illuminate the tape, and soft plastic gripping pads positioned to better retain a belt clip. 
       FIG. 2  is a cross sectional view of a tape measure similar to that shown in  FIG. 1  showing alternative embodiments of the improvements shown in  FIG. 1 . 
       FIG. 3  is a perspective view of showing the rear side portion of the belt clip shown in  FIG. 2 . 
       FIG. 4  is a plan view of the end portion of the tape and member shown in  FIG. 2 . 
   

   The following is a discussion and description of the preferred specific embodiments of this invention, such being made with reference to the drawings, wherein the same reference numerals are used to indicate the same or similar parts and/or structure. It should be noted that such discussion and description is not meant to unduly limit the scope of the invention. 
   DESCRIPTION OF THE INVENTION 
   Turning now to the drawings and more particularly to  FIG. 1  we have a perspective view of a tape measure having improvements thereon comprising the invention herein.  FIG. 2  is a cross sectional view of a tape measure similar to that shown in  FIG. 1  showing alternative embodiments of the improvements shown in  FIG. 1 . Most generally an improved tape measure for making an internal measurement from a member  18  (or alternatively for making an internal measurement between two generally parallel members  18 ,  16 ) has a tape  22  coiled in a housing  24  having a tape hook  26  external to the housing  24  on an unattached end portion of the tape  22 , and measurement lines  28  and numerals  30  on a concave side portion of the tape  22  which increment from the hook  26  and which can be read when the hook  26  is pulled from the housing  24 , wherein the improvement comprises: a non slip means  34  positioned along an outside face portion of the hook  26  so that when the outside of the hook  26  is pressed against one member  18  it will be less inclined to slip therealong. 
   The non slip means  34  might comprise horizontal ridges, burred edges, matrix of rough points or a small sticky plastic pad (none shown). Within this application plastic is defined to include a synthetic or natural rubber.  FIG. 1  shows a non slip means  34  which is a rough surface having a multiplicity of rough points  36 .  FIG. 2  shows a nonslip means  34  which comprises barbed points  38 . 
   A light  40  is positioned to illuminate a measured length on the tape  22 . In one embodiment of the invention the light  40  most preferably is a light intermitting diode LED  41 . A light switch  42  to is positioned to be operated in conjunction with the tape brake  46 . Most preferably the light switch  42  comprises a slide button  44  centrally positioned on the tape brake  46 . If the light  40  comprises a focused light  48 , or laser  50 , and is positioned to illuminate the measured length on the tape  22  then the problem of parallax is largely avoided. If the tape  22  comprises numerals  30  for outside measurement of one color and numerals  31  for inside measurement of a different color and if the numerals  31  for inside measurement significantly contrast with a color of the light emitting diode  41  then the numerals  31  for inside measurement will significantly stand out from the outside measurement numerals  30  when the light emitting diode  41  is switched on. 
   When the tape measure  20  comprises a belt clip  50  having a downwardly extending arm  52  which is attached to a broad side of the housing  24 , if a soft plastic gripping pad  56  is positioned on either the belt clip arm  52  or the broad side of the housing  24  adjacent to the arm  52 , then better adhesion is provided when the belt clip  50  is engaged on a worn belt  10 . In a preferred embodiment of the invention the belt clip arm  52  has an opening  54  therethrough and the gripping pad extends through the opening  54  as well as over and around the opening  54  on both a belt side and an opposite side of the belt clip arm  52 .  FIG. 3  is a perspective view showing the rear side portion of the belt clip  50  shown in  FIG. 2 . Please note two alternative styles of gripping pads  56  positioned on arm  52  as shown in  FIG. 1  and  FIG. 2 . The gripping pad  56  may alternatively, or additionally, be placed on the housing  24  adjacent to a lower portion of the belt clip arm  52 . Again please note two alternative styles of gripping pads positioned on the housing  24  adjacent to the lower portion of the belt clip  52 . To provide better gripping the gripping pad  56  may comprise a raised area on either the belt clip  50  or the housing  24 . 
   A method of taking an internal measurement between generally parallel members  16 ,  18  with a tape measure  20  having a tape  22  coiled in a housing  24 , a tape hook  26  external to the housing on an unattached end portion of the tape  22 , measurement lines  28  and numerals  30  on a concave side portion of the tape  22  which increment from the hook  26  and which can be read when the hook is pulled from the housing  24  comprises the steps of: positioning a non slip means  34  along an outside edge portion of the hook  26  on the tape measure  20 ; and, pressing the non slip means  34  on the outside of the hook  26  against one member  18  with the hook  26  so that the hook  26  will be less inclined to slip therealong. 
   More specifically wherein the tape measure  20  comprises a light  40  positioned to illuminate a measured length on the tape  22 , the above method further comprises the step of switching on the light  40  when measuring. If the light  40  comprises a light emitting diode  41  and wherein the tape comprises numerals for outside measurement of one color and numerals for inside measurement of a different color and wherein the numerals for inside measurement significantly contrast with a color of the light emitting diode then the numerals for inside measurement will significantly stand out from the numerals for outside measurement when the light  41  is switched on. If the light  40  comprises a focused light  48 , the focused light  41  may be configured so that the problem of parallax is largely avoided. 
   If the tape measure  20  is provided with a belt clip  50  having a downwardly extending arm  52  attached to a broad side of the housing  24  and a soft plastic gripping pad  56  is positioned on one of the belt clip arm  52  and the broad side of the housing  24  adjacent to the arm  52 ; then the method may further comprise the step of clipping the tape measure  20  to a worn belt  14  to thereby provide better adhesion when the belt clip  50  is engaged on the worn belt  14 . 
   While the invention has been described with preferred specific embodiments thereof, it will be understood that this description is intended to illustrate and not to limit the scope of the invention, which is defined by the following claims.