Abstract:
A measuring device having a housing and a slot therein with a retractable coiled flexible measuring tape. A plurality of rotatable reels are mounted on separate axes in the housing. A flexible measuring tape having measuring indicia thereon is coiled around the plurality of rotatable reels with a free end of the flexible measuring tape passing through the slot. A coil spring is operably coupled to at least one of the plurality of rotatable reels biasing the flexible measuring tape toward a retracted position.

Description:
TECHNICAL FIELD  
       [0001]     This invention relates to measuring devices and, more particularly, to measuring devices using a flexible tape retractably coiled inside a housing.  
       BACKGROUND  
       [0002]     Measuring devices using retractable coiled flexible tapes mounted inside a housing are well known in the art. A common type of such a measuring device has a housing having a slot. A flexible tape having measuring indicia thereon is coiled around a reel mounted inside the housing with a free end of the flexible tape extending through the slot. A retraction mechanism, typically a coil spring, acts upon the reel biasing the flexible tape in the retracted position. In use, a user pulls enough of the flexible tape from the housing through the slot to make the desired measurement using the indicia located on the flexible tape. When the user has completed making the measurement, the flexible tape is rewound onto the reel and stored inside the housing. Such common retractable flexible tape measuring devices are found in many toolboxes around the world.  
         [0003]     Over the years, many variations of the basic flexible retractable tape measuring device have been made.  
         [0004]     An example is seen in U.S. Pat. No. 6,276,071, Khachatoorian, Tape Measure With Tape Breaking Control Mechanism, discloses a spring-loaded tape cartridge in a tape measure including a coilable tape rotatably mounted to position a free end of the tape to pass through an opening in the housing. The tape cartridge is biased to retract the tape into the compartment when the free end is pulled out of the housing to perform a measurement. A stop tab at the free end engages the workpiece and assures that the free end remains outside the housing and available for gripping. An internal spring portion acts between the housing and the tape cartridge for applying a substantially constant frictional force on the tape cartridge. This particular measuring device has a second spring portion for selectively applying increased and decreased frictional forces on the tape cartridge to supplement the substantially constant frictional force. A locking member is provided for selectively applying a substantially normal pressure to the tape, transverse to the movement path, to positively lock the tape against the housing and prevent the tape from moving relative to the housing.  
         [0005]     U.S. Pat. No. 6,349,482, Gilliam, Three Position Locking Mechanism For a Tape Measure, discloses a retractable tape measure having a flexible tape biased in a coiled position and a housing to contain the flexible tape. The flexible tape ( 20 ) is coiled around one shaft ( 24 ). A tape biasing device ( 40 ) is mounted within the housing using a spring ( 42 ) strung between two separate shafts (see  44  and  46 ) separate from the axis of the flexible tape ( 20 ). The tape measure also includes a locking mechanism ( 50 ).  
         [0006]     U.S. Pat. No. 5,119,521, Clontz, Tape Measure for Hand Tools, discloses a tape measure frame assembly for installation within the handle of a hand tool. The assembly includes a gearing connection between the tape and a retracting spring, which enables the assembly to be elongated in conformity with the tool handle. Coiled spring ( 12 ) is wrapped in two coils ( 12 A and  12 B) around shafts ( 16  and  15 , respectively). Flexible tape (T) is wrapped around a single rotatable shaft ( 20 ).  
         [0007]     U.S. Pat. No. 5,414,943, Vogt, Anatomical Measuring Tape With Indicator, discloses a measuring device with a different twist. The measuring device has two measuring tapes held on separate reels in a housing. The housing has two windows for displaying measurement indicia appearing on each tape. The tapes are spring biased toward the fully wound condition. The two tapes contained within one housing are held on separate reels and operate independently. Each tape is held on a single reel.  
         [0008]     U.S. Pat. No. 5,832,622, Mann, Direct Reading Inside and Outside Tape Measure, discloses a measuring tape which allows both inside and outside dimensions to be read directly from the same printed face of the tape. The tape measure has a case having a tape coiled inside the case and extending out of the case through a slot in the case. Inside the case is a guide wheel which guides the tape along a bottom wall of the case. The front wall of the case is transparent so that the graduations on the tape can be seen adjacent to the bottom wall. A pointer on the case points to the graduations such that when the tape is fully retracted, the pointer points to a measurement corresponding to the width of the case. This enables the case and the tape to be used to make inside measurements. Flexible measuring tape ( 20 ) is wound around single reel ( 24 ) inside the case to form a coil. A separate wheel ( 34 ) is fixed on shaft ( 32 ) which forces tape ( 20 ) near wall ( 22 ) as tape ( 20 ) is unwound from reel ( 24 ) around which tape ( 20 ) is stored.  
         [0009]     It is also desirable to be able maximize the length of measurement which can be taken with the flexible tape measuring device. This can be done by increasing the length of the flexible tape stored within the housing. However, since a given flexible tape has a finite thickness, the more tape that is wrapped around the storage reel inside the housing, the greater the diameter of the wound reel. The greater the diameter of the wound, the greater the overall size of the housing must be. Not only does the an increased housing size take up more space in a tool box, but, more importantly, the larger the measuring device in the hand of the user, the more difficult that it is to hold comfortably and reliably. Thus, common flexible tape measuring devices have a realistic maximum amount of flexible tape that can be reasonably stored within the housing based upon the thickness of the flexible tape and a required maximum housing size for comfortable and reliable use. While flexible tapes possibly can be made thinner allowing more tape to be held on the reel, a thinner tape usually does not perform as well in taking measurements. It is desirable to have a flexible tape which is thick enough to have some rigidity so it is easier for one person to make a measurement. Thus, thinner tape is not the answer either.  
       SUMMARY OF THE INVENTION  
       [0010]     The present invention provides a flexible tape measuring device which achieves the advantage of holding a greater amount of flexible tape than prior art devices while maintaining a comfortable easy-to-use size and form factor. Alternatively, a similar length of flexible tape may be used but a thicker tape can be used with the flexible tape being relatively stiffer when withdrawn from the housing making it easier for one person to perform relatively longer distance unsupported measurements.  
         [0011]     The present invention achieves these advantages, in part, by storing the flexible tape around a plurality of reels inside the housing rather than around a single reel. Storing the flexible tape around a plurality of reels on separate axes allows not only the diameter of a plurality of reels to store the retracted flexible tape but also the distance between the plurality of reels. This allows for much more flexible tape of a given thickness to be stored in the housing. While the plurality of reels take more space than a single reel, the plurality of reels actually achieves a smaller profile since the flexible tape is wound around and around both reels taking advantage of the distance between the reels. The resultant housing containing the plurality of reels may be made more rectangular, and less square, than conventional flexible tape measuring devices. The more rectangular shape allows a shorter, for instance, and longer housing for a given amount of flexible tape of a given thickness. The shorter height allows the measuring device to fit more comfortably and reliably in the hand of a user than would a more squarish conventional flexible tape measuring device. Further, the more rectangular housing better supports the flexible tape in an extended position due to the mechanical advantage of the rectangular housing.  
         [0012]     The present invention provides a measuring device having a housing having a slot therein. Rotatable reels are mounted on separate axes in the housing. A flexible measuring tape having measuring indicia thereon is coiled around the plurality of rotatable reels with a free end of the flexible measuring tape passing through the slot. A coil spring is operably coupled to at least one of the plurality of rotatable reels biasing the flexible measuring tape toward a retracted position.  
         [0013]     In a preferred embodiment, the flexible measuring tape is coiled around two rotatable reels.  
         [0014]     In a preferred embodiment, the coil spring is mounted on a third axis between the separate axes.  
         [0015]     In a preferred embodiment, the separate axes are positioned forward and aft from a direction in which the flexible measuring tape extends through the slot.  
         [0016]     In a preferred embodiment, an opposite end of the flexible measuring tape from the free end is affixed to one of the rotatable reels.  
         [0017]     In a preferred embodiment, the coil spring is operably coupled to the rotatable reels.  
         [0018]     In a preferred embodiment, the coil spring is operably coupled to at least one of the rotatable reels with gears.  
         [0019]     In a preferred embodiment, a belt is positioned around the rotatable reels between each of the rotatable reels and the flexible measuring tape.  
         [0020]     In a preferred embodiment, the belt couples the rotatable reels in common rotatable relationship.  
         [0021]     In an alternative embodiment, the present invention provides a method of assembling a measuring device having a housing with a slot therein. A plurality of rotatable reels are mounted on separate axes in the housing. A flexible measuring tape having measuring indicia thereon is coiled around the plurality of reels with a free end of the flexible measuring tape passing through the slot. A coil spring is coupled to at least one of the plurality of rotatable reels biasing the flexible measuring tape toward a retracted position.  
         [0022]     In an alternative embodiment, the present invention provides a method of using a measuring device to obtain a measurement. The measuring device has a housing having a slot therein, a plurality of rotatable reels mounted on separate axes in the housing and a flexible measuring tape having measuring indicia thereon. The flexible measuring tape is coiled around the plurality of rotatable reels with a free end of the flexible measuring tape passing through the slot. The flexible measuring tape is pulled from the slot of the housing. The measurement is obtained. The flexible measuring tape is stored around the plurality of rotatable reels within the housing. 
     
    
     BRIEF DESCRIPTION OF THE DRAWING  
       [0023]      FIG. 1  is a partial perspective view illustrating the preferred embodiment of the measuring device of the present invention minus the reels onto which the flexible tape is mounted;  
         [0024]      FIG. 2  is a partial perspective view illustrating the preferred embodiment of the measuring device of the present invention minus the housing encompassing the reels. flexible tape, belt, spring and gears;  
         [0025]      FIG. 3  is a partial perspective view illustrating the preferred embodiment of the measuring device of the present invention showing the interaction of the reels, belt and gears;  
         [0026]      FIG. 4  is the partial perspective view of  FIG. 3  taken from the opposite side; and  
         [0027]      FIG. 5  is a partial perspective view illustrating the preferred embodiment of the measuring device of the present invention showing the interaction between the reels, belt, gears and the housing but minus the spring and the flexible tape.  
     
    
     DETAILED DESCRIPTION  
       [0028]     Conventional flexible tape measuring devices use a single reel to store flexible tape inside a housing. The single reel typically includes a coil spring wound on the inner diameter of the reel with the flexible tape wrapped around the outer diameter of the reel. A flexible tape measuring device having a 25 foot (7.6 meter) flexible tape typically has a reel having an inner diameter of 2 inches (5.1 centimeters) with an outer diameter, including the flexible tape, of 2.64 inches (6.7 centimeters). The outer diameter of the reel has a circumference of approximately 6.31 inches (16.0 centimeters). Therefore, one wrap of the flexible tape around the reel stores approximately 6.31 inches (16.0 centimeters) of flexible tape. In order to accommodate a 25 foot (7.6 meter) flexible tape, the flexible tape must be wrapped around the reel approximately 48 times. The more times that the flexible tape is wrapped around the reel, the larger the outside diameter of the reel becomes.  
         [0029]     The present invention stores the flexible tape by wrapping or coiling the flexible tape around multiple reels. The multiple reel flexible tape storage allows the measuring device of the present invention to use thicker tapes, differing tape material or allows a more compact, easier to handle, housing design.  
         [0030]     A preferred embodiment of the measuring device  10  is illustrated in  FIG. 1 . Measuring device  10  is enclosed in housing  12  having an opening, such as a slot,  14  through which a free end  16  of flexible tape  18  extends. Flexible tape  18  is stored wrapped or coiled around two reels (not shown, however, shafts  20 ,  22 , onto which the two reels are mounted, are shown in  FIG. 1 ). Preferably, free end  16  of flexible tape  18  has lip  24  which prevents flexible tape  18  from being withdrawn completely into housing  12  through slot  14  when measuring device  10  is not being used. Free end  16  of flexible tape  18 , prevented from being withdrawn into housing  16 , is then available to be grasped by the user when measuring device  10  is next used. Coil spring  26 , as will be more fully illustrated and explained with respect to later Figures, operates in conjunction with gear  28  to tension at least one of the reels and, hence, flexible tape  18  for retraction into a withdrawn or wound configuration.  
         [0031]     When measuring device  10  is not being used, flexible tape  18  is almost fully stored wound around the two reels mounted on shafts  20 ,  22 . When measuring device is used, the user grasps free end  16  of flexible tape  18  and pulls a desired length of flexible tape  18  from housing  12  through slot  14 . Flexible tape  18  at least partially unwinds from reels mounted on shafts  20 ,  22  as flexible tape  18  is drawn from housing  12 . The amount of flexible tape  18  which can be drawn from housing  12 , and thus used for measuring purposes, is limited by the amount of flexible tape  18  stored on reels mounted on shafts  20 ,  22 . Flexible tape  18  has measuring indicia, such as feet and inches and fractions thereof marked thereon to facilitate measurements. It is preferred that flexible tape  18  be somewhat cupped when drawn in its free state outside of housing  12  in order to provide some rigidity to flexible tape  18  when used for unsupported measuring purposes.  
         [0032]     As can be seen in  FIG. 1 , shafts  20 ,  22  have separate axes and are spaced apart a distance which allows flexible tape  18  to be stored not only on both reels but also in the distance between the reels as indicated by shafts  20 ,  22 . Shafts  20 ,  22  are positioned front and back, or forward and aft, with respect to a front of housing  12  as represented by slot  14 . Positioning shafts  20 ,  22  in this manner allows housing  12  to have a longer front to back dimension and a shorter top to bottom dimension than would have been feasible had flexible tape  18  been stored wound on a single reel.  
         [0033]      FIG. 2  provides a somewhat different view of the same measuring device as previously illustrated in  FIG. 1 . In  FIG. 2 , measuring device  10  is partially illustrated without housing  12  for greater clarity. Front reel  30  is mounted on shaft  20  (illustrated in  FIG. 1 ) and rear reel  32  is mounted on shaft  22  (also illustrated in  FIG. 1 ). Belt  34  is positioned around front reel  30  and rear reel  32  ensuring that both front reel  30  and rear reel  32  operate in synchronized rotation. Tape  18  is again wound or coiled around front reel  30  and rear reel  32  outside of belt  34  and the space between front reel  30  and rear reel  32 . Coil spring  26  is mounted on a separate shaft  36  positioned between front reel  30  and rear reel  32 . Mounting coil spring  26  in this position increases the amount of flexible tape  18  which may be stored in housing  12  by both eliminating the space on one of either front reel  30  or rear reel  32  by the thickness of coil spring  26  and by lengthening the distance between shafts  20 ,  22  increasing the storage space between front reel  30  and rear reel  32 .  
         [0034]      FIG. 3  and  FIG. 4  illustrates a more detailed view of the operation of the reels  30 ,  32 , belt  34  and gears, including gear  28 , of measuring device  10  first illustrated in  FIG. 1 . The view illustrated in  FIG. 3  and  FIG. 4  does not include, for clarity purposes, housing  12 , flexible tape  18  nor coil spring  26 . Belt  34  is shown positioned around front reel  30  and rear reel  32  in order to maintain rotational consistency between front reel  30  and rear reel  32 . When measuring device  10  is fully assembled, flexible tape  18  (not shown) would be wound around both front reel  30  and rear reel  32  outside of belt  34 . Coil spring  26  (not shown) is positioned on its own axis on spring shaft  36  located between shafts  20 ,  22 . Gear  28  is rotationally fixed to spring shaft  36  or coil spring  26 . Gear  28  mates with reel gear  38  that is rotationally fixed to front reel  30  or shaft  20 . Coil spring  26  keeps gear  28  in rotational tension which, in turn, keeps front reel  30 , via reel gear  38 , in rotational tension. Since flexible tape  18  (not shown) is wound around rear reel  32 , flexible tape  18  is also in rotational tension with a tendency to be retracted into housing  12  and stored wound around front reel  30  and rear reel  32 . It is preferred that gear  28  have more teeth than reel gear  38  for mechanical advantage.  
         [0035]     Note that gear  28  is rotationally coupled to front reel  30  via reel gear  38  and that rear reel  32  is rotationally coupled to front reel  30  via belt  34 . It is to be recognized and understood that coil spring  26 , rear reel  32  and front reel  30  may be kept rotationally coupled in other manners. For example, gear  28  may be rotationally coupled via a gearing arrangement to rear reel  32  instead of to front reel  30 . Further, it is possible that gear  28  may also be mechanically coupled through a gearing arrangement with front reel  30  as well as to rear reel  32 . This arrangement could eliminate the need for belt  34 . And it is further contemplated that in an embodiment that coil spring  26  may be wound on either front reel  30  or rear reel  32 , or both, eliminating the need for separate spring shaft  36 .  
         [0036]      FIG. 5  shows yet another illustration of measuring device  10  first illustrated in  FIG. 1  which shows front reel  30 , rear reel  32 , belt  34  and gear  28  mounted inside housing  12 . For clarity, the view illustrated in  FIG. 5  does not include coil spring  26  or flexible tape  18 .  
         [0037]     It is to be recognized and understood that while measuring device  10  has been described in a preferred embodiment in  FIGS. 1 through 5  as having two reels (front reel  30  and rear reel  32 ), that measuring device  10  could be constructed having more than two reels. For example, measuring device  10  of the present invention could have a third reel to support an even greater distance around which flexible tape  18  could be stored further increasing the capacity of measuring device  10 . By extension, further reels could also be added.  
         [0038]     Measuring device  10  of the present invention may accommodate flexible tapes  18  of differing thicknesses and lengths by varying the reel diameter and by varying the distance between front reel  30  and rear reel  32 . For instance, measuring device  10  using a 25 foot (7.6 meter) flexible tape could have two reels having an outer diameter, including flexible tape  18 , of 1.60 inches (4.1 centimeters). The distance between shafts  20 ,  22  would be 3.75 inches (9.5 centimeters) apart. This arrangement would have a circumference for storing flexible tape  18  of approximately 11.4 inches (29.1 centimeters). For a 25 foot (7.6 meter) flexible tape  18 , flexible tape  18  would need to be wrapped around reels  30 ,  32  about 26.3 times.  
         [0039]     Currently, plastic tapes are not used in conventional flexible tape measuring devices (generally flexible tape measuring devices using flexible tapes of 25 feet (7.6 meters) or less) because the thickness of a plastic tape is typically 3 to 4 times thicker (approximately 0.025 inches (0.6 millimeters)) than that of steel tapes (typically 0.0067 inches (0.17 millimeters).  
         [0040]     Use of a thicker flexible tape  18  would allow a user to extend the flexible tape  18  unsupported over a longer distance. For example, the Stanley™ Fat Max™ measuring tape advertises an unsupported distance of 11 feet (3.35 meters) using 0.0067 inch (0.17 millimeters) thick flexible tape. Measuring device  10  of the present invention could extend this unsupported distance at 13 feet (4.0 meters) using a slightly thicker 0.0082 inch (0.21 millimeters) thick flexible tape  18 .  
         [0041]     Further, the multiple reel design of measuring device  10  of the present invention allows a housing  12  better adapted to fit the user&#39;s hand. Housing  12  can be shaped more like a handle than a conventional tape measure case that is shaped like a square with rounded corners or a circular shaped object. Housing  12  for the preferred embodiment of the present invention using a 25 foot (7.6 meter) flexible tape  18  could be designed having overall dimensions of 1.5 inches (3.8 centimeters) wide, 5.5 inches (14.0 centimeters) in length and only 1.75 inches (4.45 centimeters) in height. This compares to typical dimensions of a convention flexible tape measuring device, using the same 25 foot (7.6 meter) flexible tape are 1.5 inches (3.8 centimeters) wide, 3 inches (7.6 inches) in length and 3 inches (7.6 inches) in height. Thus, the multiple reel design of the present invention has reduced the overall height of measuring device  10  by approximately 1.2 inches (3.18 centimeters). This smaller dimension makes measuring device  10  much easier to fit in a user&#39;s hand enabling the user to use measuring device  10  longer, by reducing fatigue, and more reliably. The longer and shorter dimensions of measuring device  10  provide the user with a more “handle-like” mechanical advantage allowing the user to better support flexible tape  18  in an extended position.  
         [0042]     Various modifications and alterations of this invention will be apparent to those skilled in the art without departing from the scope and spirit of this invention. It should be understood that this invention is not limited to the illustrative embodiments set forth above.