Abstract:
A dual mode tape rule blade arrestor structure that provides for an effective increase in tape rule rewind buffering to prevent excessive blade retrieval speeds that generate high impact sheering forces. The arrestor button of the present invention is pressed upward to temporarily halt tape rule rewinding, but can at the same time also be pressed downward and locked into the full constraint position. As such, the improved structure of the invention herein enhances tape rule service life as well as operating safety.

Description:
BACKGROUND OF THE INVENTION 
     1) Field of the Invention 
     The invention herein relates to a dual mode tape rule blade arrestor structure that provides for an effective increase in tape rule rewind buffering to prevent excessive blade retrieval speeds that generate high impact sheering forces; the arrestor button of the present invention is pressed upward to temporarily halt tape rule rewinding, but can at the same time also be pressed downward and locked into the full constraint position; as such, the improved structure of the invention herein enhances both tape rule service life and operating safety. 
     2) Description of the Prior Art 
     A conventional tape rule is internally comprised of a tape rule blade reel that consists of a center-wound spiral spring at the interior section and a tape rule blade wound around the exterior section, with a hook riveted to the front end of the tape rule blade and the center section of the said tape rule blade reel spiral spring sleeved over a center shaft of a left case half; the front end of the tape rule blade is inserted through a bumper block which is secured by a fastening tab at the bottom section and front end of the left case half and the other side of the bumper block is secured by a fastening tab at the bottom section and front end of the right case half; screws are respectively inserted into screw holes in the said right case half and then fastened into the center shaft and the mounting posts of the left case half to complete the assembly of the tape rule. The conventional product is utilized by pulling out the tape rule blade of the tape rule to an appropriate length during a measurement operation and then releasing the tape rule hook of the tape rule when measuring is finished; since the spiral spring (similar to the type utilized in many spring-loaded mechanisms) inside the tape rule is capable of automatically rewinding the tape rule blade and, furthermore, the rewinding speed increases in proportion to the length the tape rule blade is extended, if the said ruler blade is constructed of metal, the user is susceptible to cutaneous injuries of the hand, which is an inconvenient shortcoming of the conventional tape rule. Furthermore, the faster the rewinding speed, the greater the impact force of the tape rule hook against the bumper block, and since the cushioning performance of the conventional bumper block structure is not optimal, the tape rule hook often becomes dislodged, a serious drawback that renders the conventional tape rule unusable. However, to innovate a more practical and convenient tape rule, the inventor of the invention herein conducted exhaustive research and development based on many years of professional manufacturing experience and, furthermore, subjected the results to extensive testing and further refinement to achieve an even higher level of practical value, which finally culminated in the dual mode tape rule blade arrestor structure of the invention herein. 
     SUMMARY OF THE INVENTION 
     The primary objective of the invention herein is to provide a dual mode tape rule blade arrestor structure, wherein the arrestor button is pressed upward to temporarily halt tape rule rewinding and, furthermore, the arrestor button is pressed downward and locked into the full constraint position to increase buffering efficiency and decrease rewinding impact force, the improved structure thereby enhancing tape rule operation safety as well as service life. 
     To enable the examination committee to further understand the structural characteristics and technological content as well as the advantages and innovative features of the invention herein, the brief description of the drawings below is followed by the detailed description of the invention herein. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is an isometric drawing of the invention herein. 
     FIG. 2 is an exploded drawing of the invention herein. 
     FIG. 3 is an isometric drawing of the left case half  4  of the invention herein. 
     FIG. 4 is an isometric drawing of the right case half  3  of the invention herein. 
     FIG. 5 is an isometric drawing of the arrestor button  8  of the invention herein. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring to FIG. 1, FIG. 2, FIG. 3, FIG. 4, and FIG. 5, the dual mode tape rule blade arrestor structure of the invention herein is comprised of a right case half  3 , a left case half  4 , a bumper block  5 , a tape rule blade reel  7 , and an arrestor button  8 , of which: 
     The left case half  4  is of one-piece plastic construction; the said left case half  4  has a center shaft  41  projecting from the middle of the interior and, furthermore, a tapped mounting post  42  projecting from the lower front end of the interior, a mounting post  43  projecting from lower rear end of the interior, a fastening tab  44  disposed at the lower end of the said tapped mounting post  42 , and a plurality of ribs  45  protruding along the lower surface of the said left case half  4  interior; additionally, an arced mounting fixture  46  extends between the tapped mounting post  42  and the fastening tab  44 , and a fastening slot  47  is formed in the upper edge of the said left case half  4 . 
     The right case half  3  is of one-piece plastic construction; the right case half  3  has a center screw hole  31  projecting from the middle of the interior and, furthermore, a screw hole  32  formed in the lower front end of the interior, a hole  33  formed at the lower rear end of the interior, a fastening tab  34  disposed at the lower end of the said screw hole  32 , and a plurality of ribs  35  protruding along the lower surface of the said right case half  3  interior; additionally, an arced mounting fixture  36  extends between the screw hole  32  and the fastening tab  34 , and a fastening slot  37  is formed into the upper edge of the said right case half  3 . 
     The tape rule blade reel  7  consists of a center-wound spiral spring  71  installed at the middle of the interior with a tape rule blade  72  wound around its exterior section, a tape rule hook  73  riveted to the front end of the tape rule blade  72 , and a rim  74  and  75  along each of the two sides of the tape rule blade reel  7 , with a beveled surface  751  formed laterally along the outer edges of the said rims  74  and  75 . 
     The arrestor button  8  is of one-piece plastic construction with a push block  81  projecting from the exterior center section and the said arrestor button  8  has a temporary stop appendage  82 ; an engagement slot  83  and  85  is disposed in each of the two sides of the temporary stop appendage  82  and, furthermore, an angled surface  84  and  86  is formed at each of the outer sides of the said engagement slots  83  and  85 ; a stay element  87  extends from the lower aspect of the said arrestor button  8  and, furthermore, a curved thrust pad  88  protrudes along the exterior center surface of the temporary stop appendage  82 . 
     The spiral spring  71  of the tape rule blade reel  7  is sleeved onto the center shaft  41  of the left case half  4  and the front end of the tape rule blade  72  is inserted though the bumper block  5  which is secured to the fastening tab  44  in the bottom section at the front end of the left case half  4 ; one side of the said arrestor button  8  is inserted and positioned into the arced mounting fixture  46  of the left case half  4 ; the right case half  3  is then placed over such that the other side of the said bumper block  5  is secured to the fastening tab  34  in the bottom section at the front end of the right case half  3  and, furthermore, the other side of the said arrestor button  8  is inserted and positioned into the arced mounting fixture  36  of the right case half  3 ; two screws  2  are respectively inserted into the center screw hole  31  and the screw hole  32  and fastened to the center shaft  41  and the tapped mounting post  42  of the left case half  4  to conjoin the tape rule into a single structural entity. 
     As to the said structural component assembly of the invention herein, the said tape rule blade  72  is pulled out for utilization and released when utilization is completed; since the spiral spring  71  inside the tape rule blade reel  7  is capable of automatically rewinding the tape rule blade  72 , when the tape rule blade  72  is being rewound, the user moves the arrestor button  8  upward and presses it inward, causing the engagement slots  83  and  85  and the angled surfaces  84  and  86  at the two sides of the temporary stop appendage  82  to make frictional contact with the rims  74  and  75  along the two sides of the tape rule blade reel  7  and thereby achieving transient rewind buffering or the arrestor button  8  is pressed downward until the it is locked into the full constraint position against the tape rule blade  72 ; as such, the arrestor button  8  of the invention herein is simultaneously capable of two arrestive modes. 
     In summation of the foregoing section, the invention herein effectively improves upon the shortcomings of the conventional product and in terms of application is genuinely an original innovation compared to similar category products and, furthermore, is of greater utilitarian performance. Since the disclosed structure is capable of achieving the claimed objectives, the invention herein is submitted to the examination committee for review in application for the granting of the commensurate patent rights.