Abstract:
A power operated tape measure enables measuring tape extension through a drive mechanism, as well as measuring tape retraction. A tape cartridge assembly including an annular reel, a measuring tape wound onto the reel, as well as a spring coupled with the reel, and is positioned within a housing shell of the tape measure. A drive mechanism accomplishes tape extension out of the housing shell, and optionally, tape retraction into the housing shell by engaging with a surface of the measuring tape. A primary actuator initiates input on one or more switches that selectively control operation of the drive mechanism, and includes a lever arm for a user to make selections regarding tape extension and retraction. A retraction actuator is moveable by a user to cause the drive mechanism to become disengaged from the surface of the tape, whereby spring powered retraction of the tape is permitted.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
   This application is a continuation of U.S. application Ser. No. 11/277,684, filed Mar. 28, 2006, and entitled “SIMPLE CONTROLLER FOR A POWER OPERATED TAPE MEASURE”. 

   STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
   Not applicable. 
   BACKGROUND OF THE INVENTION 
   This invention relates generally to retractable tape measurement devices. More particularly, the present invention is directed to a tape measure requiring a simple range of user inputs to accomplish tape extension and retraction. 
   Tape measurement devices of the type employing a tape retraction feature, also referred to as “tape measures”, generally have a housing formed by opposed sidewalls and with an aperture to allow an elongated tape or “blade” having measurement indicia to extend out of and retract into the housing as needed. The tape is typically wound on a reel in a coil rolled manner with the reel being rotatably mounted within the housing between the sidewalls. A first end of the tape may be attached to the reel and second free end of the tape typically has a stop or hook to prevent the second end from entering the housing. A retracting means, such as a recoil spring, is coupled with the reel to rotate the reel in a direction to wind the tape onto the reel and retract the tape into the housing. Alternatively, if a stationary reel is used to guide winding of the tape, the retracting means may be directly attached to the tape. A user can pull on the stop against the force of the retracting means to extend the tape out of the housing for making a measurement. 
   Tape measures with retraction features have evolved to include power operated tape extension as a convenience to users. Some of these power operated tape measures include a drive mechanism for the tape that couples a motor with a gear or roller system that engages a bottom or outwardly exposed surface of the tape while the tape is wound on the reel. The motor may then drive the unwinding of the tape from the reel through the gear/roller system so that the tape extends out of the housing a selected amount. Motorized tape retraction involves driving the tape in the opposite direction from extension to rewind the tape onto the reel. Power operated tape extension is also beneficial when a user does not have two free hands to allow for holding of the tape measure housing in one hand and pulling the tape to a desired length with the other hand. 
   It would be desirous to improve the ease of operation for users of power operated tape measures, while providing a reliable design. Some prior art powered tape measures employ extension and/or retraction mechanisms that are complex or cumbersome to operate single handedly. 
   BRIEF SUMMARY OF THE INVENTION 
   A tape measure of the present invention provides for power operated tape extension, and optionally, power operated tape retraction into a tape measure housing. Beneficially, tape extension and retraction features may be controlled by input on an actuator in simple, opposed motions. 
   In one aspect, the tape measure has a housing shell within which is positioned a tape cartridge assembly. The tape cartridge assembly includes an annular reel with a tape having a bottom surface wound thereon and being under the influence of a spring for biasing the tape into a wound position on the reel. Extension of the tape out of the housing shell is accomplished by a drive mechanism that engages with the bottom surface of the tape and an associated power source electrically coupled with the drive mechanism. One or more switches control power flow between the power source and the drive mechanism to enable tape extension, and optionally, tape retraction into the housing shell. A primary actuator operably mounted within the housing shell presents a body overlying a portion of the tape cartridge and an arm extending from the periphery of the body through an opening in the housing shell. The arm is moveable in opposed forward and backward directions to cause the actuator to move and selectively initiate input on the one or more switches regulating drive mechanism activity. Movement of the arm to a forward position enables the drive mechanism to cause tape extension. Likewise, movement of the arm to a rearward position allows for tape retraction. Additionally, a retraction actuator is moveable by a user to cause the drive mechanism to become disengaged from the surface of the tape, whereby spring powered retraction of the tape is permitted. 
   In another aspect, the one or more switches include a first switch interconnected with the actuator body by a resilient member transferring motion of the actuator into movement of the first switch between an activated position, when the actuator arm is in the forward position, and a deactivated position, when the actuator arm is in a middle or rest position between the forward and rearward positions. The drive mechanism also includes a frame for supporting a drive wheel. The frame is pivotably coupled with the housing and is biased in a direction that urges the drive wheel into engagement with the tape bottom surface. In this way, movement of the arm to the rearward position causes a back end of the actuator to apply a force on the frame that overcomes the biasing on the frame and moves the drive wheel out of engagement with the bottom surface of the tape so that a spring load on the reel retracts the tape back into the housing shell. 
   Both a first switch and a second switch are provided in another aspect of the invention for coupling with the drive mechanism. The tape measure may therefore enable both power operated tape extension and retraction by the first switch activating drive mechanism operation in a forward direction corresponding with the actuator arm being in the forward position and the second switch activating drive mechanism operation in a rearward direction corresponding with the actuator arm being in a first rearward position. The drive mechanism includes a frame, with a drive wheel rotatable mounted thereon that is pivotably mounted within the housing shell and biased in a direction that urges the drive wheel into engagement with the tape bottom surface. Thus, retraction of the tape into the housing under the influence of a spring load on the reel—as opposed to being through power operated tape retraction—may be had through movement of the arm to a second rearward position behind the first rearward position, where a back end of the actuator applies a force on the frame that pivots the frame to move the drive wheel along an arcuate path away from the tape bottom surface. 
   In yet another aspect of the invention, first and second switches are separated by the actuator. The switches are positioned to enable both power operated tape extension and retraction as the result of contact with the actuator when it is moved to a forward position or a rearward position respectively. A separate mechanical tape retraction actuator is provided opposite the actuator for controlling power operation, such that a portion of the retraction actuator is accessible through an opening in the bottom of the housing to permit retraction of the tape into the housing under the influence of a spring load on the reel. Movement of the retraction actuator in a rearward direction pivots the drive wheel out of abutting contact with the bottom surface of the tape, thereby permitting the recoil spring to act upon the reel and withdraw the tape. 
   The tape measure may also be provided with a blade wiper mechanism to prevent the accumulation of contaminants on the bottom surface of the tape that may interfere with the ability of the drive mechanism to drive the tape out of or into the housing. Similarly, a guide collar and/or rolling blade support may be provided at the opening in the housing where the tape extends therethrough to support the extension of the tape during use. 

   
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING 
     In the accompanying drawings which form a part of the specification and are to be read in conjunction therewith and in which like reference numerals are used to indicate like elements in the various views: 
       FIG. 1  is a side elevational view of one embodiment of a tape measure of the present invention, partially in section, with the actuator for controlling tape extension and retraction in a rest position; 
       FIG. 2  is a side elevational view of the tape measure of  FIG. 1 , with the actuator in a forward position for activating powered tape extension; 
       FIG. 3  is a side elevational view of the tape measure of  FIG. 1 , with the actuator in a rearward position for activating spring operated tape retraction; 
       FIG. 4  is an enlarged fragmentary side elevational view of the tape measure of  FIG. 3 , with various components removed to show the drive mechanism disengaged from the tape; 
       FIG. 5  is a side elevational view of another embodiment of a tape measure of the present invention, partially in section, including switches for initiating powered tape extension and powered tape retraction and with the actuator for controlling tape extension and retraction in a rest position; 
       FIG. 6  is a side elevational view of the tape measure of  FIG. 5 , with the actuator in a forward position for activating powered tape extension; 
       FIG. 7  is a side elevational view of the tape measure of  FIG. 5 , with the actuator in a first rearward position for activating powered tape retraction; 
       FIG. 8  is a side elevational view of the tape measure of  FIG. 5 , with the actuator in a second rearwards position for activating spring operated tape retraction; 
       FIG. 9  is a perspective view of the tape measure of  FIG. 5  with a portion of the housing removed to show various internal components thereof; 
       FIG. 10  is a side elevation view of yet another embodiment of a tape measure of the present invention, with portions of the housing cut away for clarity, and illustrating a drive mechanism actuator in a rest position and a manual retraction actuator in a rest position; 
       FIG. 11  is a side elevation view of the tape measure of  FIG. 10 , with the retraction actuator in a use position, whereby the drive wheel has been removed from abutting contact with the bottom surface of the tape; 
       FIG. 12  is a fragmentary side elevation view of the tape measure of  FIG. 10 , with the drive mechanism actuator in a forward position, whereby a first switch is engaged for activating powered tape extension; 
       FIG. 13  is a fragmentary side elevation view of the tape measure of  FIG. 10 , with the drive mechanism actuator in a rearward position, whereby a second switch is engaged for activating powered tape retraction; and 
       FIG. 14  is fragmentary bottom perspective view of a blade wiper mechanism for engaging the bottom surface of the tape with a portion of the housing removed to show various internal components thereof. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   Referring now in more detail to the drawings, and initially to  FIG. 1 , there is illustrated an embodiment of a tape measure of the present invention designated by the reference numeral  10 . The tape measure  10  has a housing shell, or housing,  12  enclosing various components that control operation of the tape measure  10 , as will be more fully explained below with reference to  FIGS. 2-4 . An exemplary shape for the housing  12  is illustrated in  FIG. 9 , and may be implemented with another tape measure  100  embodiment shown in  FIGS. 5-9 , as well as with the embodiment of the tape measure  10  shown in  FIGS. 1-4 . 
   A tape cartridge assembly  14  is mounted within the housing  12  for storage of elongate tape  16 . The assembly  14  includes a cartridge cover  18  that is coupled to the interior of the housing  12  and a reel  20  rotatably mounted with and surrounded by the cartridge cover  18 . The cartridge cover  18  may be formed of two halves that mate in clamshell fashion. The elongate tape  16  is attached with the reel  20  on a trailing end of the tape so that it may be wound thereon for storage. Preferably, a biasing means (not shown) of the conventional type, such as a spring, is coupled with the reel  20  to urge rotation of the reel  20  within the cartridge cover  18  in a direction as to wind the tape  16  onto the reel  20  and thereby retract an amount of extended tape back into the housing  12 . Measurement indicia are also marked along a top surface  22  of the elongate tape  16  so that an amount of the tape  16  extended out of a lower opening  24  in the housing shell  12  can be used to make a measurement of the length of an object adjacent to the tape  16 . A hook or stop  26  extends downwardly from distal end  28  of the elongate tape  16  to prevent retraction of the proximal end  28  into the housing  12 . A guide roller  34  may also be positioned within the housing  12  for directing the elongate tape  16  through the lower opening  24  into and out of the housing  12 . 
   As seen in a neutral or rest position in  FIG. 1 , the elongate tape  16  of the tape cartridge assembly  14  moves under the influence of a drive mechanism  30 , in addition to the biasing means coupled with the reel  20 . The drive mechanism  30  is engagable with a bottom surface  32  of the elongate tape  16  to impart a force thereon sufficient to overcome the biasing on the reel  20  in the opposing direction to rotate the reel  20  and thereby drive the tape  16  in a longitudinal direction out of the housing  12 , as depicted in  FIG. 2 . Conversely, disengaging of the drive mechanism  30  from the tape bottom surface  32  allows the biasing on the reel  20  to retract the amount of the elongate tape  16  extended out of the housing  12  back into the housing, as depicted in  FIGS. 3 and 4 . The structural components and operational schemes of the drive mechanism  30  will be explained in more detail below. 
   An electrical circuit is formed through the electrical coupling of the drive mechanism  30  with a power source  34  and an electrical switch  36 . The power source  34  may include, for instance, a battery  37  (or batteries) received within a battery chamber  38  positioned within the housing  12 . In this embodiment, the electrical switch  36  preferably moves between “on” and “off” positions to regulate the flow of current between the power source  34  and the drive mechanism  30 . Thus, movements of the electrical switch  36 , through electrical coupling and decoupling of the drive mechanism  30  and the power source  34 , selectively control extension of the elongate tape  16  out of the housing  12 . As can be observed, electrical wiring forming a circuit between the drive mechanism  30 , the power source  34  and the switch  36  has been removed in  FIGS. 1-4  to provide an unobstructed view of the various components of the tape measure  10  within the housing  12 . However, those of skill in the art will appreciate that conventional electrical connections may be made between the drive mechanism  30 , the power source  34  and the switch  36  to enable the operation of drive mechanism  30 . 
   The drive mechanism  30  is preferably formed as a unit with a housing  39  that is coupled to an interior of the housing  12  of the tape measure  10 . An electric motor  40  of the drive mechanism  30  receives power from the power source  34 , as regulated by the electrical switch  36 , to provide the necessary torque for driving the rotation of a drive wheel  42  against the elongate tape  16  for tape extension, as seen in  FIG. 2 . The output torque of the motor  40  reaches the drive wheel  42  through various gears or contact rollers. To provide support when the drive wheel  42  is either in a position of engagement with the elongate tape  16  or disengaged and spaced from the tape  16 , the drive wheel  42  is rotatably mounted to a moveable frame  44 . Preferably, the frame  44  forms a post  46  that is slidably received through a bracket  48  of the drive mechanism housing  38  that also allows for a range of pivotable motion for the post  46 . A spring  50  seated on the bracket  48  pushes upward on a pin  52  of the post  46  to thereby urge the post  46  upward relative to the bracket  48  and the drive wheel  42  into contact with the bottom surface  32  of the elongate tape  16 . Additionally, an opening  41  is formed in the cartridge cover  18  of the tape cartridge assembly  14  to enable the drive wheel  42  to move into frictional engagement with the tape bottom surface  32 . 
   To provide for user control over the extension and retraction of the elongate tape  16 , an actuator  54  is pivotably mounted within the housing  12  and extends over a portion of the tape cartridge assembly  14 . Through motion of the actuator  54 , input may be initiated on the switch  36 , to regulate electrical operation of the drive mechanism  30  for tape extension, and on the post  46 , to control mechanical decoupling of the drive wheel  42  from the tape bottom surface  32  to allow the biasing on the reel  20  to retract the amount of elongate tape  16  payed out back into the housing  12 . The actuator  54  includes a body  56  having an arcuate upper shelf  58  and at least one sidewall  60  extending downwardly from the upper shelf  58 . The sidewall  60  has a lower region  62  that may be pivotably connected to the tape cartridge assembly  14  at, for example, the axis of rotation of the reel  20 . Alternatively, the pivotable connection of the sidewall  60  may be with the housing  12 . In either case, the pivotable motion of the actuator  54  enabled through a force input to a lever arm  64  extending from the actuator upper shelf  58  moves the body  56  generally over and around a portion of the tape cartridge assembly  14 . The lever arm  64  may extend radially outward from the pivotable attachment point of the actuator  54  and through an upper opening  66  in the housing  12 . By having the axis of rotation of the actuator  54  parallel to, or coaxial with, the axis of rotation of the tape reel  20 , forward and backward motion on the lever arm  64  is aligned with the longitudinal direction of tape movement into and out of the housing  12 . Therefore, intuitively, forward motion on the lever arm  64 , as depicted in  FIG. 2 , provides the user with control of tape extension, and rearward movement on the lever arm  64 , as depicted in  FIG. 3 , provides the user with control of tape retraction features of the tape measure  10 . 
   Coupling of the actuator  54  with the switch  36  in the present embodiment is accomplished by a resilient strap member  68 . The strap  68  has opposing first and second end regions  70 ,  72 , each with an aperture. The switch  36  is coupled with the aperture of the first end region  70 , and a pin  74  extending outwardly from the upper shelf  58  of the actuator  54  rearwardly from the lever arm  64  is placed within the aperture of the second end region  72 . Preferably, the switch  36  is a momentary slider switch that is moved between an “on” position, allowing current to flow from the power source  34  to the motor  40  of the drive mechanism  30 , and an “off” position, cutting off the flow of current to the motor  40 . Because of the resilient nature of the strap  68 , a certain amount of pushing force may be applied by the strap  68  to the switch  36  through a rearward movement of the lever arm  64  (e.g., to move the switch into the “off” position). However, the strap  68  is also sufficiently flexible as to buckle when the lever arm  64  continues in a rearward motion past the neutral or rest position shown in  FIG. 1  to the position necessary to accomplish mechanical decoupling of the drive mechanism  30  from the elongated tape  16  as shown in  FIGS. 3 and 4 . This buckling results because the switch  36  has reached the “off position” but the pin  74  to which the strap  68  is attached at the second end region  72  continues on a rotational path generally towards the drive mechanism  30 . 
   A trailing edge  76  of the sidewall  60  of the actuator body  56  intersects with the upper shelf  58  at a back end region of the actuator body  56 . Formed at the back end region is an extension  80  that contacts an upper end  82  of the drive mechanism post  46  to impart a force on the post  46 . When the lever arm  64  is moved sufficiently rearwardly, a force is applied by the extension  80  substantially downwardly on the post  46  that overcomes the expansion force of the spring  50  and displaces the post  46  downwardly. An axle  82  of the drive wheel  42  travels within a guide  84  to direct the wheel  42  away from the bottom surface  32  of the elongate tape  16  as the post  46  is moving downwardly. The position of the drive wheel  42  when the lever arm  64  is in the full rearward position is best seen in  FIG. 4 , and results in the mechanical decoupling of the drive mechanism from the tape. 
   In operation, the tape measure  10  functions in three operating modes: a rest mode, a tape extension mode and a tape retraction mode.  FIG. 1  depicts the tape measure  10  in the rest mode where the lever arm  64  of the actuator  54  is in a neutral position between forward and rearward positions. At this point, the strap  68  has the slider switch  36  in the “off” position, and the spring  50  urges the post  46  upwardly to maintain the drive wheel  42  in contact with the bottom surface  32  of the elongate tape  16 . Upon the user moving the lever arm  64  to the forward position shown in  FIG. 2 , the strap  68  pulls the slider switch  36  to the “on” position, enabling the flow of current from the power source  34  to the motor  40  to provide torque to the drive wheel  42  and drive the tape  16  out of the housing  12 . Once the desired amount of tape  16  for measuring has been payed out, the lever arm  64  is returned to the neutral position and the strap  68  pushes the slider switch  36  to the “off” position, stopping the motor  40  and drive wheel  42  movement. The return of the lever arm  64  to the neutral position may be accomplished by the user or the actuator  54  or the slider switch  36  may be biased to return the lever arm  64  to the neutral position upon removal of a forward force on the lever arm  64  by the user. Upon stopping of the motor  40 , the drive wheel  42  cooperates with the motor&#39;s neutral resistance to be rotated backwardly to hold the tape in the extended position. 
   To retract a desired amount of the extended tape  16  back into the housing  12 , the lever arm  64  is pulled in a direction opposite of the direction for tape extension, i.e., rearwardly as shown in  FIG. 3 . Sufficient rearward movement of the lever arm  64  causes the extension  80  to move the post  46  substantially in the downward direction and overcomes the upward urging provided by spring  50 . Once the drive wheel  42  is released from engagement with the tape bottom surface  32 , the biasing on the reel  20  causes the reel to rotate in a direction to wind the tape  16  thereon and thus retract the tape  16  into the housing  12 . If the lever arm  64  is released, the spring  50  urges the arm  64  back to the neutral position and the post  46  upwardly to reengage the drive wheel  42  with the tape bottom surface  32 . Therefore, the user can selectively retract some or all of the extended tape  16  back into the housing  12  depending on input provided to the actuator  54 . Additionally, movement of the lever arm  64  to the rearward position causes the strap  68  to buckle, as illustrated in  FIGS. 3 and 4 . 
   Turning to  FIGS. 5-9 , another embodiment of the tape measure  100  of the present invention is provided. Many components of the tape measure  10  illustrated in  FIGS. 1-4  are present in the embodiment of the tape measure  100  illustrated in  FIGS. 5-9 , and therefore references to shared components between the embodiments will be abbreviated in the following discussion of the tape measure  100 . 
   The tape measure  100  includes a housing shell  102  enclosing a tape cartridge assembly  104 , a drive mechanism  106 , a power source  108  and a pair of electrical switches  110   a  and  110   b  electrically coupled with the drive mechanism  106 , and an actuator  112  initiating input on the switches  110   a  and  110   b  to drive powered tape extension and retraction, as well as enabling mechanical decoupling of the drive mechanism  106  from the tape cartridge assembly  104 . The tape measure  100  provides the added functionality of powered tape retraction in addition to powered tape extension through the use of forward and reverse switches  110   a  and  110   b  and a reversible electric motor  114  of the drive mechanism  106 . It should be understood that for the tape measure  100  embodiment of  FIGS. 5-9 , the tape cartridge assembly  104  and the power source  108  may be the same as the tape cartridge assembly  14  and the power source  34 , respectively, of the embodiment of the tape measure  10  of  FIGS. 1-4 . Furthermore, as with the previous embodiment, the drive mechanism  106  may also include various gears and contact rollers to transfer output torque from the motor  114  to a drive wheel  116  engagable with an elongate tape  118  wound onto a rotatable reel  119  of the tape cartridge assembly  104 . Within the housing shell  102 , a guide roller  122  directs the elongate tape  118  through a lower opening  120  of the shell  102  during tape extension and retraction. 
   As shown in  FIG. 5 , when the actuator  112  is in a neutral or rest position, no input is provided on switches  110   a  or  110   b  and the drive wheel  116  is contacting a bottom surface  124  of the elongate tape  118 . The drive mechanism  106  may have a housing  126  rigidly affixed within the housing shell  102  so that the mechanism  106  is formed as a unit. A frame  128  to which the drive wheel  116  is rotatably mounted is coupled with the housing  126  for pivotable movement in relation to the housing  126 . An upper section  130  of the frame  128  has a spring  132  connected thereto for urging pivoting of the frame  128  and movement of the drive wheel  116  upwardly and towards the elongate tape  118 . The drive wheel  116  is mounted to a lower section  134  of the frame  128 . Opposed ends of the spring  132  are connected with a bracket  136  of the drive mechanism housing  126  and with a post  138  of the frame  128 . In the neutral or forward position of the actuator  112 , depicted in  FIGS. 5 and 6 , respectively, the actuator  112  does not contact the post  138  and thus does not affect the drive wheel positioning  116  relative to the elongate tape  118 . The spring  132 , therefore, maintains the frame  128  at a position to ensure frictional engagement between the drive wheel  116  and the tape bottom surface  124  for driving extension and retraction of the elongate tape  118 . 
   The actuator  112  is similar to the actuator  54  of the tape measure  10  embodiment of  FIGS. 1-4 , and includes a body  140  having an arcuate upper shelf  142  and at least one sidewall  144  extending downwardly from the upper shelf  142 . The actuator  112  may be pivotably connected to the tape cartridge assembly  104  (or alternatively, to the housing shell  102 ) at a lower region  146  of the sidewall  144  along an axis parallel with, or identical to, the axis of rotation of the reel  119 . Pivotable motion of the actuator  112  is initiated through forward and backward motion of a lever arm  148  extending generally radially outward from the upper shelf  142  of the actuator  112  and through an upper opening  150  of the housing shell  102 . 
   A projecting member  152  extends outwardly from the actuator body  140  generally at a back end  153  of the upper shelf  142  and is configured for contacting the switches  110   a  and  110   b  through a range of pivotable motion of the actuator  112  as directed on the lever arm  148 . Additionally, the sidewall  144  has a rearward portion that is formed into an extending leg  154  for contacting the post  138  of the frame  128  supporting the drive wheel  116 . In this way, when the lever arm  148  is moved to a most rearward, as position shown in  FIG. 8 , the leg  154  moves the frame  128  downwardly through the pivoting motion thereof and the drive wheel  116  in an arcuate path away from the elongated tape  118  to disengage the drive mechanism  106  from the tape  118 . With the drive mechanism  106  disengaged, the biasing on the reel  119  causes the reel  119  to rotate in a direction so as to retract the tape  118  into the housing shell  102 . 
   A set of electrical wiring  156  connects the power source  108  with the electrical switches  110   a  and  110   b  and the reversible electric motor  114 . By the projecting member  152  of the actuator  112  contacting the forward electrical switch  110   a , current is directed from the power source  108  through the motor  114  in a direction so as to cause the drive wheel  116  to drive extension of the elongate tape  118  out of the housing shell  102 . Conversely, contacting the rearward electrical switch  110   b  directs current from the power source  108  through the motor  114  in a direction so as to cause the drive wheel  116  to drive retraction of the elongate tape  118  back into the housing shell  102 . 
   As can been seen in  FIGS. 5-9 , the tape measure  100  functions in four operating modes: a rest mode, a powered tape extension mode, a powered tape retraction mode, and a non-powered tape retraction mode. In the rest mode illustrated in  FIG. 5 , the lever arm  148  positions an apex  158  of the projecting member  152  between the switches  110   a  and  110   b , so that neither switch is activated. Moving the lever arm  148  to the forward position, shown in  FIG. 6 , causes the projecting member apex  158  to initiate input on the forward switch  110   a  and activates the motor  114  to drive tape extension from the housing shell  102 . Likewise, moving the lever arm  148  to a first rearward position, shown in  FIG. 7 , causes the projecting member apex  158  to initiate input on the rearward switch  110   b  and activates the motor  114  to drive tape retraction into the housing shell  102 . At the first rearward position, the extending leg  154  of the actuator  112  moves close to the pin  138 , but does not displace the frame  128 , thereby leaving the drive wheel  116  still engaged with the bottom surface  124  of the elongate tape  118 . The non-powered tape retraction mode is reached when the lever arm  148  is moved rearwardly beyond the first rearward position to a second rearward position, shown in  FIG. 8 . This movement positions the projecting member apex  158  rearwardly of the switches  110   a  and  110   b  and causes the extending leg  154  to overcome the upward biasing of the frame  128  by the spring  132  through contacting the frame post  138  and rotating the frame  128  and attached drive wheel  116  away from the elongate tape  118 . This mechanical decoupling of the drive mechanism  106  from the tape  118  allows for tape retraction through biasing on the reel  119  without the need for motor  114  operation. For instance, a user may wish to use powered tape retraction to more slowly and precisely retract a certain amount of tape  118  into the housing shell  102  and leave some tape extended for making a length measurement. On the other hand, non-powered tape retraction saves battery power by avoiding the use of the power source  108 , and may result in increased speed of tape  118  retraction if spring biasing on the reel  119  is sufficiently strong. 
   Turning to  FIGS. 10-13 , yet another embodiment of the tape measure  200  of the present invention is provided. Many components of the tape measure  100  illustrated in  FIGS. 5-9  are present in the embodiment of the tape measure  200  illustrated in  FIGS. 10-13 , and therefore references to shared components between the embodiments will be abbreviated in the following discussion of the tape measure  200 . 
   Like the tape measure  100 , the tape measure  200  includes a housing shell  202  enclosing a tape cartridge assembly  204 , a drive mechanism  206 , a power source  208 , a pair of electrical switches  210   a  and  210   b  electrically coupled with the drive mechanism  206 , and a drive mechanism actuator  212  for initiating input on the switches  210   a  and  210   b  to activate powered tape extension and retraction. However, unlike the tape measure  100 , where the actuator  112  is also capable of enabling mechanical decoupling of the drive mechanism  106  from the tape cartridge assembly  104 , the tape measure  200  is provided with a separate manual tape retraction actuator  214  to provide the user with the ability to mechanically decouple the drive mechanism  206  from the tape cartridge assembly  204  to permit conventional spring powered retraction of the tape. Accordingly, the tape measure  200  provides the same functionality as the tape measure  100 , namely, powered tape retraction in addition to powered tape extension, through the use of forward and reverse switches  210   a  and  210   b  and a reversible electric motor  216  of the drive mechanism  206 , and spring powered tape retraction. 
   As with the embodiment of the tape measure  100  of  FIGS. 5-9 , it should be understood that the tape cartridge assembly  204  and the power source  208  will be the same as the tape cartridge assembly  14  and the power source  34  respectively of the embodiment of the tape measure  10  of  FIGS. 1-4 . Furthermore, as with the previous embodiment, the drive mechanism  206  may also include various gears and contact rollers to transfer output torque from the motor  216  to a drive wheel  218  that is engagable with a bottom surface  220  of an elongate tape  222  that is wound onto a rotatable wheel  224  positioned within the tape cartridge assembly  204 . 
   As shown in  FIG. 10 , when the drive mechanism actuator  212  is not acted on by a user, the drive mechanism actuator  212  is held in an intermediate rest position by a wire spring  226 . In the rest position, the drive mechanism actuator  212  does not engage either the extension switch  210   a  or the retraction switch  210   b . The wire spring  226  is positioned among retention posts  228  formed on an outer surface of the tape cartridge  204 . 
   To initiate powered tape extension, the user would move the drive mechanism actuator to  12  from the rest position of  FIG. 10  to a forward position, illustrated in  FIG. 12 , by pushing a lever arm  230  of the drive mechanism actuator  212  forward. In the forward position, a forward face  232  of the actuator  212  depresses and thereby activates the extension switch  210   a , thereby activating the drive mechanism  206  to extend the tape  222  from the housing  202 . When the actuator  212  is in it&#39;s forward position, a forward arm  234  of the wire spring  226  is flexed against the lower left retention post  228   a , as illustrated in  FIG. 12 . 
   When the tape  222  has been extended a desired distance, the user removes forward pressure from the lever arm  230 . In turn, the tension on the forward arm  234  of the wire spring  226  resulting from the forward arm being flexed about the retention post  228   a  biases the drive mechanism actuator  212  back to the rest position. As the forward arm  234  moves back to its unflexed position (illustrated in  FIG. 10 ), the drive mechanism actuator  212  is returned to its rest position and the extension switch  210   a  is deactivated. 
   Similarly, when a user desires to power retract the extended tape  222 , the user pulls the lever arm  230  rearwardly, thereby moving the drive mechanism actuator  212  from its rest position of  FIG. 10  to a rearward position illustrated in  FIG. 13 . In the rearward position, a rearward face  236  of the drive mechanism actuator  212  depresses and thereby activates the retraction switch  210   b , thereby activating the reversible motor  216  such that the drive mechanism  206  causes the tape  222  to be recoiled back into the cartridge  204 . 
   When the drive mechanism actuator  212  is in the rearward position, a rearward arm  238  of the wire spring  226  is flexed rearwardly about the retention post  228   b . The flexure of the rearward arm  238  biases the drive mechanism actuator  212  back to its rest position. When the operator has retracted a desired amount of the tape  222 , the user removes the rearward pressure on the lever arm  230 . In turn, the rearward arm  238  of the wire spring  226  moves the drive mechanism actuator  212  back to its rest position as the tension created by the flexure of the rearward arm  238  is released. As the drive mechanism actuator  212  returns to its rest position, the rearward face  236  is moved out of engagement with the retraction switch  210   b  and the reversible motor  216  is deactivated. 
   In addition to providing the user with an option of retracting the tape  222  into the housing  202  via the power driven motor  216 , the tape measure  200  also provides the user with the option of retracting the tape  222  into the housing  202  manually under conventional spring power. This is especially useful in the event that the power source  208  becomes unavailable (e.g., the batteries die). As discussed in connection with the embodiments above, a recoil spring (not shown) positioned within the cartridge  204  biases the reel  224  to rewind any amount of the tape  222  that has been withdrawn from the housing  202 . The biasing caused by the recoil spring is overcome by the natural tendency of the drive mechanism  206  to resist movement when the motor  216  is not activated. Accordingly, to enable the recoil spring to withdraw the extended tape  222  into the housing  202 , the drive mechanism  206  must be mechanically decoupled from the bottom surface  220  of the elongate tape  222 . In order to facilitate such decoupling, the tape measure  200  is provided with the manual retraction actuator  214 . 
   The retraction actuator  214  is biased by a spring  240  to a rest position, which is illustrated in  FIG. 10 . The retraction actuator  214  has a user engagable tab  242  that extends through an aperture  244  in a lower portion of the housing  202 . The retraction actuator  214  is slidably movable in a rearward direction from the rest position, illustrated in  FIG. 10 , to the use position illustrated in  FIG. 11 . The retraction actuator  214  includes an upwardly directed flange  246  at a rearward portion thereof. The flange  246  is designed to abut a downwardly depending arm  248  that is mechanically coupled with the frame  128  that supports the drive wheel  218 . It should be readily understood that the arm  248  could be an integral part of the frame  128 . 
   As the retraction actuator  214  is moved from its rest position in  FIG. 10  to its use position in  FIG. 11 , the retraction actuator  214  engages the arm  248  and further rearward movement of the actuator  214  causes rotation of the frame  128  away from the cartridge  204 , thereby removing the drive wheel  218  from abutting contact with the bottom surface  220  of the tape  222  coiled on the reel  224 . As discussed above, this mechanical decoupling of the drive mechanism  206  from the tape  222  permits the recoil spring to rotate the reel  224  to retract the tape  222  into the housing  202 . When a desired amount of the tape  222  is retracted into the housing  202 , the user can release the rearward pressure on the tab  242 , thereby permitting the spring  240  to pull the retraction actuator  214  back to its rest position of  FIG. 10 . Simultaneously, the spring  132  will rotate the frame  128  back to a position where the drive wheel  218  engages the bottom surface  220  of the tape  222  coiled on the reel  224 , thereby stopping rotation of the reel  224  and further spring powered retraction of the tape  222  into the housing  202 . 
   Turning now to  FIG. 14 , in addition to the inclusion of the guide roller  34 , any of the embodiments disclosed herein may be provided with additional items to support the tape  16 , such as a collar  250  and a wiper mechanism  252 . The collar  250  may take the form of a molded plastic piece having an aperture therethrough. The aperture is preferably arcuate in shape to permit a lower surface of the aperture to support the blade  16  by abutting the bottom surface  32  of the blade  16  across its entire width during operation. Similarly, the wiper mechanism  252  is provided with a wiper insert  254 . The insert  254  is provided with an arcuate cutout  256  adjacent an upper edge thereof for supporting, abutting, and wiping, the bottom surface  32  of the blade  16  during use. The wiper mechanism  252  also includes a frame  258  for receiving the insert  254 . The frame  258  includes a tubular member  260  which is slidably received on a pin  262  that is supported by the housing  12 . The frame  258  is thereby rotatably mounted on the pin  262 . A spring  264  biases the insert  254  into abutting contact with the bottom surface  32  of the blade. 
   The insert  254  is preferably made out of a soft resilient material, such as felt, and is provided to “wipe” the bottom surface  32  of the tape  16  during use to prevent the build up of contaminants on the bottom surface  32  of the tape  16  that might interfere with the ability of the drive wheel  42  to move the tape  16  and/or prevent its movement when so desired. As it is the frictional relationship between the drive wheel  42  and the bottom surface  32  of the tape  16  which permits the drive mechanism  30  to control movement of the tape, the wiper mechanism  252  assists with providing a clean surface with which the drive wheel  42  cooperates. Additionally, if the drive wheel  42  is rubber in nature, the wiper mechanism  252  can also “wipe off” any particles of the rubber wheel which may over time work free from the drive wheel  42  and adhere to the bottom surface  32  of the tape  16 . 
   From the foregoing it will be seen that the various embodiments of the tape measure of the present invention provide for simple and intuitive control of measuring tape extension and retraction through certain forward and backward motions on an actuator. Various modifications may be made to the embodiments of the tape measure described herein without departing from the scope of the invention. It will be understood that certain features and subcombinations are of utility and may be employed without reference to other features and subcombinations. This is contemplated by and is within the scope of the present invention. It is also to be understood that all matter herein set forth or shown in the accompanying drawings is to be illustrative of applications of the principles of the invention, and not in a limiting sense.