Abstract:
A measuring tape housed within an ergonomically configured housing with a spirally wound spring motor is disclosed which facilitates the paying out and retraction of the flexible metal blade carrying the measuring indicia thereon.

Description:
CROSS-REFERENCE TO RELATED APPLICATION  
       [0001]     This application claims the benefit of U.S. provisional patent application Ser. No. 60/459,528, filed Apr. 1, 2003. 
     
    
     BACKGROUND OF THE INVENTION  
       [0002]     1. Field of the Invention  
         [0003]     This invention relates to measuring tapes and more particularly to a measuring tape housed within an ergonomically configured housing with a spirally wound spring motor facilitating the paying out and retraction of the flexible metal blade carrying the measuring indicia thereon.  
         [0004]     2. Description of the Prior Art  
         [0005]     The conventional measuring tape structure typically includes a housing containing an elongate blade of flexible material such as cloth, metal, or plastic carrying the measuring indicia such as inches, feet, yards, for example, wound around a rotatable shaft which is spring loaded. In use, the leading free end of the blade may be pulled from the housing a sufficient amount to expose enough of the blade to accomplish the desired measuring function. Upon completion of the measuring function, the exposed portion of the blade may be released and allowed to be retracted into the housing by the associated spring and wound onto the spring biased rotating shaft.  
         [0006]     While the presently available measuring tapes usually function without fault, as the requirement for measuring longer lengths has required the associated housings to become quite large in order to accommodate the increased length of measuring blade wound upon the spring biased rotatable shaft.  
         [0007]     In order to maintain the overall exterior dimension within the limits of the grasp of the user and to permit the assembly to be carried by an associated tool, for example, the spring and the flexible blade were longitudinally spaced apart. Such structure is illustrated in U.S. Pat. No. 5,119,521 issued Jun. 9, 1992 to William C. Clontz.  
         [0008]     Although the aforementioned design was functional, the system included a complex combination of several cooperating gears and the use of a pair of spaced apart shafts for the expansion and retraction of a coiled spring.  
       SUMMARY OF THE INVENTION  
       [0009]     It is an object of the present invention to produce a measuring tape including a housing capable of accommodating a relatively extensive flexible blade containing the measuring indicia carried on one rotatably mounted shaft and a longitudinally spaced spirally wound spring motor rotatably mounted on a second shaft and coupled to the first shaft by an associated driving belt.  
         [0010]     Another object of the invention is to produce a measuring tape containing a first rotatably mounted shaft for the measuring indicia carrying blade and a spirally wound spring motor mounted on a second shaft wherein the indicia containing blade and the spring motor are coupled together. As the blade is caused to be payed off of the first shaft, the spring motor is caused to be wound, tightening the coils of the spring motor on the second shaft. When the blade is finally allowed to return into the housing, the spring motor causes a rotation of the first shaft effecting a rewinding of the blade on to the first shaft.  
         [0011]     Still another object of the invention is to produce a measuring tape structure wherein a spring motor is caused to be tightened during the withdrawal of the blade and will retract the blade once the blade is released.  
         [0012]     The above objects may be achieved by a measuring tape comprising a hollow housing; a first shaft having an axis of rotation and mounted with the housing; an elongate flexible blade having a free end and a terminal end, the free end adapted to extend out of the housing, and the terminal end attached to the first shaft; a second shaft having an axis and mounted within the housing in spaced relation from the first shaft; a spiral spring mounted on the second shaft and having one end attached to the second shaft and the other end adapted to be moved to a biasing position upon movement of the blade out of the housing; and pulley and belt means for transmitting rotating movement of the first shaft to the other end of the spiral spring. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0013]     The above as well as other objects and advantages of the invention will become readily apparent to those skilled in the art from reading the following detailed description of an embodiment of the invention when considered in the light of the accompanying drawings, in which:  
         [0014]      FIG. 1  is an elevational view of one side of a measuring tape incorporating the features of the present invention, partially in section with portions cut-away is clearly illustrated in the structure thereof;  
         [0015]      FIG. 2  is an elevational view in section from the opposite side of the measuring tape illustrated in  FIG. 1 ; and  
         [0016]      FIG. 3  is an exploded perspective view of the measuring tape illustrated in  FIGS. 1 and 2 . 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0017]     Referring to the drawings, there is illustrated a measuring tape embodying the features of the invention. More specifically, there is illustrated a measuring tape having a hollow relatively elongate housing  10  which may be fabricated from any suitable material such as plastic, for example. The housing  10  is typically formed of two mating sections fastened together by threaded fasteners, for example, received within suitably disposed openings  12  integrally formed in the side wall  14  of one of the sections. The fasteners are threadably received with suitably arranged and aligned openings  12 ′ formed in the side wall  14 ′ of other of the cooperating mating sections.  
         [0018]     A stub shaft  16  is formed to extend transversely from the side wall  14  of the housing  10 . A cooperating stub shaft  17  is formed to extend transversely from the opposing side wall  14 ′ in aligned relation with the shaft  16 . A spool  18  is rotatably mounted on the shafts  16  and  17  and is adapted to receive the terminal end of a flexible blade  20 . The blade  20  is mounted in a coil form on the spool  18  wherein the leading free end  22  thereof is adapted to extend out of the housing  10  through a slot  24 . The leading free end  22  of the blade  20  is provided with an L-shaped fixture  26  adapted to function as a stop for the leading free end  22  of the blade  20 , preventing the blade  20  from retracting completely into the interior of the housing  10 . A sheave or pulley  28  is attached to the side wall of the spool  18 .  
         [0019]     A split shaft  30  is mounted to extend transversely between the side walls  14 ,  14 ′ of the housing  10  in spaced relation from the cooperating stub shafts  16  and  17 . The axes of the shafts  16 ,  17 , and  30  are disposed generally parallel with one another.  
         [0020]     A spiral spring assembly  31  including a spirally wound spring  32  is mounted on the shaft  30  such that one end of the spring  32  is attached to the shaft  30  by being fitted within the split or slotted portion thereof while the opposite end is suitably secured to a housing  33  of the spiral spring assembly  31 , as illustrated in  FIG. 3 .  
         [0021]     A sheave or pulley  34 , having a centrally disposed bearing assembly  35 , is affixed to the housing  33 . The entire spiral spring assembly  31  including the spiral spring  32 , the spring housing  33 , the sheave  34 , and the bearing assembly  35  is mounted on a boss  37  and  37 ′ which are typically formed integral with the inner surface of the side walls  14 ,  14 ′, respectively. A belt  38  drivingly interconnects the sheaves or pulleys  28  and  34 .  
         [0022]     A brake mechanism including a manually operating slide  40  having a brake pad  42  mounted at one end thereof is slidingly mounted to the housing  10 .  
         [0023]     Finger and hand inserts  44  and  46 , respectively, are suitably affixed to the outer surface of the housing  10 . The inserts  44  and  46  are typically made of an elastomeric material, such as rubber, for example.  
         [0024]     It will be noted that at least one corner of the housing  10  is formed such that the mating edges of the bottom and end wall are joined to form a right angle corner, thus permitting the assembly to be used in measuring from a structure wherein two planar surfaces are joined together at right angles to one another.  
         [0025]     In operation, the housing  10  is grasped by one hand of a user, while the other hand grasps the fixture  26  on the leading free end  22  of the blade  20 . The blade  20  is pulled out of the housing  10  to the degree necessary to accomplish the desired measuring assignment. During such operation, the coiled spring  32  is placed under tension and resists the paying off of the blade  20  from the spool  18 . At the conclusion of the measuring assignment, the fixture  26  is released allowing the spring  32  to cause rotational movement of the sheave or pulley  34 . The rotation of the sheave  34  will, in turn, cause rotation of the sheave  28  by translating motion through the associated belt  38 . Thus, the blade  20  is caused to be retracted into the housing  10  and wound about the spool  18 .  
         [0026]     In accordance with the provisions of the patent statutes, the present invention has been described in what is considered to represent its preferred embodiment. However, it should be understood that the invention can be practiced otherwise than as specifically illustrated and described without departing from its spirit or scope.