Abstract:
A tool is disclosed for tightening and trimming the loop formed by a self-locking strap around a bundle of articles. A strap stop is driven away from the apertured head of said self-locking strap by means of a carrier lever. Bearing against said apertured head is an excess strap cutter either fixed to or ratchetting within said carrier lever. Said cutter severs the excess strap protruding through said apertured head when said tool is rotated so as to engage the cutter blades with said excess strap.

Description:
BACKGROUND--FIELD OF INVENTION 
     The invention relates to a hand operated tool used for tightening and cutting the excess portion of self-locking straps and more particularly where such straps are used to bundle a plurality of conductors into cables of conductors to form a harness. 
     BACKGROUND--DESCRIPTION OF PRIOR ART 
     Heretofore bundle tie tightening and cut off tools required operational motions and had a bulk that prohibited their use in certain confined areas such as behind instrument panels. One such tool is shown in U.S. Pat. No. 4,081,002 issued Mar. 28, 1978 to Mario Violi entitled &#34;Tool for Tightening Clamps.&#34; this tool offers the capacity for remotely reaching work areas through the embodiment of a barrel-portion of considerable length. A straight line of access is still required however, and a longer barrel-portion increases the bulk of the tool. 
     A second such tool is shown in U.S. Pat. No. 3,993,109 issued Nov. 23, 1976 to William G. Fortsch entitled &#34;Strap Tightening and Severing Tool.&#34; This hand supported, hand operated tool offers simplicity and a smaller size over many prior art devices. A limit to the utility of this tool is still found, however, in its bulk. In confined areas its utility Is also limited by the required hand support and range of finger/thumb articulation during operation. 
     Another alternative is to tighten the self-locking strap with an unaided hand and then cut off the excess strap by means of a naked blade or diagonal cutters. In this manner, the bundle tie may lack sufficient tightness and the surrounding items in a confined installation may be unintentionally cut and damaged. Furthermore, an undesirable sharp end will be left protruding from the self-locking strap. 
     OBJECTS AND SUMMARY OF INVENTION 
     Accordingly it is an object of this invention to provide an improved tool for tightening self-locking straps about a plurality of articles. 
     Another object of this invention is to provide a tool which is of simple construction, having fewer parts, being smaller, lighter, less expensive to produce, easier to transport, more convenient to carry and which is usable in confined spaces. 
     Another object of this invention is to provide a tool with independent strap tightening and strap tail excess severing functions selectable by the operator. 
     A further object of this invention is to provide a tool which is self supporting while engaging the strap tail, thereby enabling the operator to change to a minimal finger grip while continuing a tightening function or commencing strap tail excess severing functions in a confined space. 
     Another object of this invention is to provide a tool enabling the operator to perform the strap tightening function in confined spaces. 
     Another object of this invention is to provide a tool enabling the operator to perform the strap tail excess severing function in a confined space. 
     Another object of this invention is to function without damaging surrounding items within a confined installation. 
     It is yet another object of this invention to provide a tool operative in confined spaces using only a thumb and two finger tips in close opposition. 
     Further objects and advantages of my invention will become apparent from a consideration of the drawings and ensuing description thereof. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Details of seven single element and one three element embodiments of the invention are shown in the accompanying drawings in which similar parts are given similar reference characters. 
     FIG. 1 is an enlarged perspective view illustrating a basic single element embodiment of the hand tool. 
     FIG. 1A shows a slotted embodiment of the tool of FIG. 1. 
     FIG. 2 is a fragmentary view of the rear of the tool of FIG. 1. 
     FIG. 3 shows the initial position of a strap head with respect to the rear of the tool of FIG. 1. 
     FIG. 4 shows a grooved modification to the rear of the tool of FIG. 1. 
     FIG. 4A shows a slotted modification of the tool of FIG. 1. 
     FIG. 5 shows the levered position of the stop head with respect to the groove of FIG. 4. 
     FIG. 6 shows a two lead helix modification to the rear of the tool of FIG. 1. 
     FIG. 7 shows the loose and tensioned positions of the stop head with respect to the helix of FIG. 6. 
     FIG. 8 shows a two faced beveled modification to the rear of the tool of FIG. 1. 
     FIG. 8A shows a slotted modification of the tool of FIG. 8. 
     FIG. 9 shows the stop head in the loose and tensioned positions with respect to the beveled faces of FIG. 8. 
     FIG. 10 is a side elevational view of the tool of FIG. 1 in its initial condition with the free tail end portion of a looped strap introduced into the tool and through the head of another strap. 
     FIG. 11 shows the rocking motion of the tool of FIG. 10 tightening a strap around a bundle of articles. 
     FIG. 12 shows the rocking motion in FIG. 11 being applied by a second like tool and stop head thereby urging the first tool and stop head forward. 
     FIG. 13 is a side elevational view of the tool of FIG. 5 showing the levering motion of the stop head urging the tool forward along the free tail end portion of a looped strap. 
     FIG. 14 shows the rocking motion of the tool of FIG. 13 applied with the stop head in the levered position tightening a strap around a bundle of articles. 
     FIG. 15 shows an alternative arrangement of the tool of FIG. 13 in relation to the free tail portion of a looped strap. 
     FIG. 16 is a sequence in side elevational view of the tool of FIG. 9 being used to cut off the excess strap tail. 
     FIG. 17 is a perspective view illustrating the holding of a three element embodiment of the hand tool. 
     FIG. 18 is an exploded perspective view of the hand tool of FIG. 17 showing the cutter wheel assembly, carrier assembly and stop assembly. 
     FIG. 19 is an exploded perspective view of the cutter wheel assembly of FIG. 18 
     FIG. 20 is an enlarged front view of the front disk of the cutter wheel assembly of FIG. 19. 
     FIG. 21 is an enlarged rear view of the front disk of the cutter wheel assembly of FIG. 19. 
     FIG. 22 is an exploded perspective view of the carrier assembly of FIG. 18 with the cover ring omitted. 
     FIG. 23 is an exploded perspective view of the stop assembly of FIG. 18. 
    
    
     DRAWING REFERENCE NUMERALS 
     15. plurality of articles 
     16. bundle tie strap 
     19. strap head of 16 
     20. basic single element tool 
     20B. grooved face embodiment of single element tool 
     20F. beveled face embodiment of single element tool 
     20H. plain face slotted embodiment of single element tool 
     21. plain face carrier lever of tool 20 
     21B. grooved face carrier lever 
     21D. helix face carrier lever 
     21F. beveled face carrier lever 
     21H. plane face slotted carrier lever 
     21J. grooved face slotted carrier lever 
     21K. beveled face slotted carrier lever 
     22. strap tail of 16 
     23. cutter of 20 secured to front of carrier lever 21 
     23H. cutter of 20H secured to front of carrier lever 21H 
     24. pair of razor blade pieces of 23 
     25. brass holder of 20 
     26. common pins holding 25 to carrier lever of 20 
     27. fulcrum groove in cutter 23 
     28. alternate fulcrum groove in cutter 23 
     29. receiving port of 23 
     30. plain face of carrier lever 21 
     30B. grooved face of carrier lever 21B 
     31. stop head 
     32. levering groove in carrier lever 21B, 21J 
     33. extreme base edge of stop head 31 
     34. two lead helix on carrier lever 21D 
     35. side limit pieces of helix 34 
     36. flats on rear of carrier lever 21D 
     37. aperture in stop head 31 
     38. extreme base corner of stop head 31 
     39. base corner of stop head 31 diagonally opposite 38 
     40. beveled face closes to cutter 23 
     41. beveled face of carrier lever 21F, 21K furthest front end most parallel to cutter 23 
     42. peak formed by intersection of faces 40 and 41 
     43. bore of single element tool 
     44. slot in side of carrier levers 21H, 21J, 21K 
     45. radius at intersection of face 41 and slot 44 on carrier lever 21K 
     50. three element embodiment of tool 
     51. cutter wheel assembly of 50 
     52. wooden center disk of 51 
     53. front brass disk of 51 
     54. rear brass disk of 51 
     55. pins holding 56 
     56. ratchet strip of 51 
     57. &#34;bow tie&#34; shaped opening of front brass disk 53 
     58. drive flange of front brass disk 53 projecting rearward within 57 
     59. drive flange parallel and diagonally opposite 58 
     60. brass reinforcing angle backing 58 
     61. brass reinforcing angle backing 59 
     62. brass guide angle adjacent drive flange 58 
     63. brass guide angle adjacent drive flange 59 
     64. razor blade piece soldered to front of brass disk 53 parallel 58 
     65. razor blade piece soldered to front of brass disk 53 parallel 59 
     66. notches of ratchet strip 56 
     70. carrier assembly of 50 
     71. ratchet pawls of 70 
     73. finger of ratchet 71 
     74. seat for 71 in 75 
     75. carrier ring of 70 
     76. cover ring of 70 
     77. internally threaded acrylic plastic cylinder of 70 
     78. internal threads of 77 
     80. stop assembly of 50 
     81. barrel portion of 80 
     82. external threads of 81 
     83. hole of barrel portion 81 
     84. shaped head from 19 with base forward within 81 
     85. shaped head from 19 with base forward and pawl finger 73 180° to 84 
     86. matching lengthwise grooves spaced at 90° around 84 and 85 
     87. base opening of shaped head 85 
     88. base opening of shaped head 84 
     89. pins holding 84 and 85 within barrel portion 81 
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Turning now to FIGS. 1 through 11, details of seven single element embodiments of bundle tie tightening and cut off tool 20 are shown. Tool 20 is of generally cylindrical configuration with elongated carrier lever 21 having an inside bore 43 to loosely accommodate a strap tail 22. Tool 20 embodies a fixed cutter 23 at the front of carrier lever 21. Cutter 23 having an elongated receiving port 29 is joined to carrier 21 by brass holder 25. In the example illustrated, cutter 23 is formed by a pair of razor blade pieces 24 soldered to brass holder 25. Brass holder 25 is secured to rigid plastic carrier 21 by means of two common pins per side. All movement between holder 25 razor blade pieces 24, and carrier lever 21 is thus prevented thereby forming one integral unit. On cutter 23, fulcrum groove 27 and alternate fulcrum groove 28 are formed parallel to strap cutter receiving port 29 by fashioning razor blade pieces 24 and holder 25. Fulcrum groove 27 and alternate fulcrum groove 28 are thus located individually at a distance from the center of receiving port 29 appropriate to the size of strap head 19 against which it will bear. Best shown in FIG. 1, alternate fulcrum groove 28 could better fit a larger size of strap head 19 than fulcrum groove 27. Shown in FIG. 1 and FIG. 2, the rear of carrier lever 21 opposite cutter 23 may terminate in a plain face 30 parallel to cutter 23. Shown in FIG. 3, a stop head 31 bears on plain face 30. 
     FIG. 4 and FIG. 5 show an alternative to plain face 30 wherein grooved face 30B, having levering groove 32, accepts the extreme base edge 33 of stop head 31 on the levered position. Groove 32 may be formed on either or both sides of bore 43 but should be parallel to strap cutter receiving port 29. 
     FIG. 6 and FIG. 7 show another alternative to plain face 30 having a quarter turn two lead helix 34 incorporating two side limit pieces 35. In the example illustrated, helix 34 is fitted removably by filing four opposing flats 36 on the rear of carrier lever 21D. Aperture 37 in stop head 31, shown by solid lines in FIG. 7, aligns initially with strap cutter receiving port 29. Shown in FIG. 7, helix 34 closely conforms to stop head 31 shown by solid lines in the initial loose position. In FIG. 7, the opposing base corners 38 and 39 of stop head 31 bear on the margins of helix 34 and are restrained laterally by side limit pieces 35 throughout the rotation of stop head 31 to the tensioned position shown by dashed lines. A helix which tensions with clockwise rotation of stop head 31 as viewed from the rear is felt most natural. 
     In FIG. 8 and FIG. 9, a further alternative to plain face 30 of FIG. 2 is shown. A pair of beveled faces 40 and 41 intersect forming peak 42 parallel to cutter receiving port 29. Beveled face 40 is cut such that its area is substantially forward of beveled face 41. In FIG. 9, stop head 31 in the loose position shown by solid lines bears on face 40 and in the tensioned position shown by dashed lines bears on face 41. Face 41 is much more closely parallel cutter 23 than is face 40. 
     Shown in FIG. 1A, a further embodiment 20H of the single element tool may be seen wherein receiving port 29 and the exit of bore 43 are joined by cutting a slot 44 radially through one side of carrier lever 21H and cutter 23H between razor blade pieces 24. 
     As shown in FIG. 4A, slot 44 may be incorporated with groove 32 to form grooved face slotted carrier 21J. 
     As shown in FIG. 8A, slot 44 may be incorporated with beveled faces 40 and 41 to form beveled face slotted carrier lever 21K. A radius 45 is formed along the intersection of beveled face 41 and slot 44. 
     Turning now to FIGS. 17 through 23, a three element embodiment of the bundle tie tightening and cut off tool 50 is shown. FIG. 17 shows tool 50 configured as a thick disk with a cylinder emerging from its rear surface axially. As shown in FIG. 18, tool 50 is comprised of three assemblies: cutter wheel assembly 51, carrier assembly 70 and stop assembly 80. As shown in FIG. 19, cutter wheel assembly 51 has a wooden center disk 52 glued between two brass disks 53 and 54. Wooden center disk 52 and rear brass disk 54 have at their centers a hole of sufficient diameter to loosely accommodate strap tail 22. Secured around the circumference of wooden center disk 52 with pins 55 is a ratchet strip 56 formed by trimming the ends and side margins from a self-locking strap 16. Notches 66 of ratchet strip 56 protrude from between disk 53 and 54. At the center of front brass disk 53 is a &#34;bow tie&#34; shaped opening 57 incorporating two drive flanges 58 and 59 which protrude from the rear surface and into the hole of wooden center disk 52. As shown in FIGS. 20 and 21, drive flanges 58 and 59 are spaced to contact and parallel the opposite surfaces of an inserted strap tail 22 at diagonal extremes of opening 57. The diagonal extremes chosen must correspond to urging ratchet strip 56 to rotate in the free direction. A counter clockwise free rotation of cutter wheel assembly 51 within carrier assembly 70 viewed from the rear is felt to be most natural. Drive flanges 58 and 59 are strengthened, in the example illustrated, by soldering brass reinforcing angles 60 and 61 to the rear surface of disk 53 as backing. Brass guide angles 62 and 63 are soldered to the rear surface of disk 53 perpendicular to drive flanges 58 and 59 spaced so as to loosely accommodate and center strap tail 22 within &#34;bow tie&#34; shaped opening 57. Also shown in FIGS. 20 and 21, two razor blade pieces 64 and 65 are soldered to the front surface of disk 53 with their cutting edges parallel to, but set back slightly from, drive flanges 58 and 59. As shown in FIG. 22, carrier assembly 70 is formed, except for three ratchet pawls 71, by cementing acrylic plastic rings axially to an internally threaded acrylic plastic cylinder 77. Each ratchet pawl 71 is formed by removing the tail 22 from a self-locking strap 16. The strap head 19 is then opened enough to accommodate cutter wheel assembly 51 by removing a section of the head opposite the pawl finger 73. Pawl finger 73 is best shown in FIG. 7. While straddling the cutter wheel assembly 51, ratchet pawls 71 are individually held in three seats 74 evenly spaced within carrier ring 75. Ratchet pawls 71 are seated so as to allow rotation of carrier assembly 70 about cutter wheel assembly 51 in the free direction only. As shown in FIG. 18, cover ring 76 is cemented to carrier ring 75, thereby securing ratchet pawls 71 in seats 74. Cutter wheel assembly 51 straddled by ratchet pawls 71 is thus retained within carrier assembly 70. Internally threaded cylinder 77 is mounted axially within carrier ring 75 and bears on the rear surface of cutter wheel assembly 51. Internal threads 78 of cylinder 77 are cut so as to carry rearward when carrier assembly 70 is rotated in the free direction with respect to cutter wheel assembly 51. As shown in FIGS. 18, 22 and 23 stop assembly 80 having external threads 82 on barrel portion 81 is carried loosely within cylinder 77 by threads 78. As shown in FIG. 23, barrel portion 81 has a lengthwise through drilled hole 83 to snugly accommodate two shaped heads 84 and 85. Heads 84 and 85 are formed by rounding two strap heads 19 to a cylindrical shape centered about their base openings 88 and 87. Within hole 83, heads 84 and 85 are stacked with base openings 88 and 87 forward and pawl fingers 73 180° apart. Stacked heads 84 and 85 are provided with four matching lengthwise grooves 86 spaced evenly along their outer surface. Heads 84 and 85 are held in alignment within hole 83 by inserting two pins 89 from each end of barrel portion 81 down the full length of grooves 86. All four pins 89 are then soldered to barrel portion 81 thereby securing shaped heads 84 and 85 within stop assembly 80. 
     Single Element Tool--Operation 
     Turning now to FIGS. 1, 2, 3, 10, 11, and 12, the operation of single element tool 20 of FIG. 1 is summarized up to the excess strap trimming step. A self-locking bundle tie strap 16 having a strap head 19 and a strap tail 22 is looped about a plurality of articles 15 to be formed into a bundle. The loop is formed by threading tail 22 of strap 16 through an aperture in head 19. Also located in head 19 is a one-way locking device (not shown) which will permit strap 16 to be drawn up on articles 15 but prevent the loop from being opened by a force applied to strap 16. Protruding from head 19, tail 22 is pulled up to a hand tight condition and then inserted through strap cutter receiving port 29, bore 43 of carrier lever 21, and stop head 31 of a second like strap 16. As shown in FIG. 10, stop head 3 and tool 20 are slid forward along strap tail 22. As shown in FIG. 3, stop head 31 bears on plain face 30. FIG. 2 best shows plain face 30 at the rear carrier lever 21 on tool 20. As shown in FIG. 10, fulcrum groove 27 and alternate fulcrum groove 28 will be brought to bear on respective parallel edges of strap head 19 when stop head 31 is snugged by hand to its forward limit. Thus as shown in FIG. 11, tool 20 becomes a tightening lever using the rear face of strap head 19 as a fulcrum when rocked about said strap head 19 within the plane formed by the loop of strap 16 about articles 15. Also shown in FIG. 11, the rocking motion of tool 20 causes strap tail 22 to be pulled through strap head 19 drawing articles 15 closer together. The tightening efficiency of the single element tool requires the portion of strap tail 22 between strap head 19 and stop head 31 to be held in tension throughout the rocking motion of the tool. Successive strap tightening steps may be accomplished by resnugging stop head 31 to its forward limit as shown in FIG. 10 and then repeating the rocking motion of tool 20 shown in FIG. 11. By resistance to the rocking motion of FIG. 11, the operator will determine the point at which sufficient tightening of strap 16 about articles 15 has been reached. Owing to slight variations in style and size of head 19, the rocking motion in FIG. 11 of tool 20 should be limited to employ either fulcrum groove 27 or alternate fulcrum groove 28 shown in FIG. 1, according to best fit. The tightening efficiency of tool 20 will thereby improve. While cutting off or trimming the excess strap tail 22 from strap 16, the portion of strap tail 22 between strap head 19 and stop head 31 should be held in tension with tool 20 returned to the initial alignment shown by solid lines in FIG. 11. As shown in FIG. 12, said tensioning as well as additional strap tightening steps may be accomplished by ganging a second like tool 20 and stop head 31 behind the first. Said tension is required while cutting off or trimming excess strap tail 22 to produce a clean cut flush with head 19. Otherwise, there is a chance of an undesirable strap tail burr or knife like point protruding from strap head 19 at the completion of excess strap tail cut off operations. 
     Turning to FIGS. 4, 5, 13, 14, and 15, the operation of grooved face single element tool 20B up to the excess strap tail trimming step is shown. In FIG. 13, the levering of stop head 31 from it initial position shown by solid lines to its levered position shown by dashed lines tensions the portion of strap tail 22 between strap head 19 and stop head 31. Extreme base edge 33 of stop head 31 best shown in FIG. 5, pivots in levering groove 32 of tool 20B best shown in FIG. 4. As shown in FIG. 14, rocking tool 20B about strap head 19 with strap tail 22 tensioned by holding stop head 31 in the levered position of FIG. 13, pulls strap tail 22 through strap head 19 thereby tightening strap 16 about articles 15. Successive tensioning steps and tightening steps may be accomplished by returning stop head 31 to the initial position shown by solid lines in FIG. 13, snugging by hand to the forward limit, then again levering stop head 31 to the position shown by dashed lines and rocking tool 20B about strap head 19. An alternative method of tensioning strap tail 22 with grooved face single element tool 20B is shown in FIG. 15. Strap tail 22 is introduced to receiving port 29 such that levering groove 32 is on the opposite side of bore 43 from extreme base edge 33 of stop head 31. From the snugged initial position shown by solid lines in FIG. 15, stop head 31 is rotated about the longitudinal axis of tool 20B either clockwise or counterclockwise 180° and held in the levered position shown by dashed lines with extreme base edge 33 pivoting in levering groove 32. For installations where space permits, said rotation of stop head 31 will slightly increase the tension of strap tail 22 over simple levering of stop head 31. Turning to FIG. 6, 7 and 11, the operation of a single element tool having carrier lever 21D modified to incorporate a quarter turn two lead helix on its rear face is detailed up to the excess strap cut off step. As shown in FIG. 7 by solid lines, strap tail 22 is passed through carrier lever 21 D, two lead helix 34 best shown in FIG. 6, and stop head 31. In the initial loose position shown by solid lines in FIG. 7, stop head 31 is snugged by hand to its forward limit resting between the two leads of helix 34. In order to tension strap tail 22, stop head 31 is rotated clockwise up to one quarter turn with respect to helix 34 on the rear of carrier lever 21D. Opposing base corners 38 and 39 of stop head 31 bear on respective leads of helix 34 throughout said rotation, thereby carrying rearward to the tensioned position shown by dashed lines in FIG. 7. While bearing on leads of helix 34, opposing base corners 38 and 39 are restrained laterally from slipping off said leads by side limit pieces 35. The portion of strap tail 22 between strap head 19 and stop head 31 is thus tensioned prior to strap tightening and excess strap tail cut off steps. Strap tightening is accomplished as shown in FIG. 11 and previously described for single element tool 20 before the excess strap tail cut off step. 
     Turning to FIGS. 8, 9 and 16, the operation of beveled faced single element tool 20F is shown. Strap tail 22 is passed through receiving port 29, carrier lever 21 F, and stop head 31. In FIG. 9 as shown by solid lines, stop head 31 is snugged by hand to its initial loose position bearing on beveled face 40. In order to tension strap tail 22, stop head 31 is then slid rearward along beveled face 40, up and over peak 42 to bear on beveled face 41 reaching the position shown by dashed lines in FIG. 9. With strap tail 22 tensioned, stop head 31 will remain on beveled face 41 with little or no assistance because beveled face 41 is nearly perpendicular to bore 43 of tool 20F. The loose fit of strap tail 22 within bore 43 best shown in FIG. 8, readily accommodates strap tail 22 throughout said sliding motion of stop 31 from beveled face 40 to beveled face 41. With stop head 31 in the tensioned position shown by dashed lines in FIG. 9, strap 16 may be tightened in successive steps by rocking tool 20F about strap head 19 as previously described for other single element embodiments of the tool. When strap 16 is determined to be sufficiently tight about articles 15, excess strap tail 22 may be cut off. As noted above, the cut off operation is accomplished with strap tail 22 held in tension between strap head 19 and stop head 31. Shown in FIG. 16, excess strap tail 22 is cut off, as with the other single element embodiments, by rotating tool 20F clockwise or counterclockwise about its longitudinal axis normal to strap head 19. Thus either or both razor blade pieces 24 are brought into severing contact with excess strap tail 22. 
     Turning to FIGS. 1A, 4A and 8A, details of operation for three embodiments of the slotted single element tool are given. In use, the incorporation of slot 44 with carrier levers 21H, 21J and 21K provides the operator with the additional options of placing or removing the single element tool on strap tail 22 while stop head 31 is in its loose or initial position. With the cutter of the tool forward, strap tail 22 may be introduced to bore 43 by aligning slot 44 with the left or right side of strap tail 22 between strap head 19 and stop head 31 then moving the slotted single element tool latterly to the initial position. Removal of the slotted single element tool from strap tail 22 is by lateral movement in the opposite direction such that strap tail 22 emerges through slot 44. Tensioning, tightening, and cut off steps are accomplished as with the other single element embodiments. As shown in FIG. 8A, carrier 21K requires a radius 45 at the intersection of slot 44 with beveled face 41 to facilitate sliding stop head 31 up and over peak 42. The additional options provided with slot 44 would be found useful in certain installations, for example, where the tool needs to be repositioned on strap tail 22. 
     Three Element Tool--Operation 
     Turning now to FIGS. 17, 18, 19, 20, 21, 22 and 23, the operation of three element tool 50 is summarized. A self-locking bundle tie strap 16 having a strap head 19 and strap tail 22 is looped about a plurality of articles to be formed into a bundle. The loop is formed by threading tail 22 of strap 16 through an aperture in head 19. Also located in head 19 is a one-way locking device (not shown) which will permit strap 16 to be drawn up on the bundle but prevented the loop from being opened by a force applied to strap 16. Strap head 19 thus holds strap tail 22 when strap 16 is drawn up to a hand tight condition. Stop assembly 80 of tool 50 is first set to the ready position within carrier assembly 70 by threading barrel portion 81 to within a thread of the forward limit of internal threads 78 such that base openings 87 and 88 align with &#34;bow tie&#34; shaped opening 57. Setting stop assembly 80 to the ready position may be accomplished by inserting the tail 22 of a like strap 26 partially into shaped head 85 from the rear opening of internally threaded acrylic plastic cylinder 77 and screwing stop assembly 80 forward while sighting through &#34;bow tie&#34; shaped opening 57 to align base opening 88 with said opening 57. As shown in FIG. 17, tool 50 is held between a thumb and the tips of two opposing fore fingers. With stop assembly 80 set to the ready position, strap tail 22 is introduced through &#34;bow tie&#34; shaped opening 57 of cutter wheel assembly 51. Brass guide angles 62 and 63 aid in centering strap tail 22 along the longitudinal axis of tool 50. Thence strap tail 22 passes through base openings 88 and 87 within stop assembly 80 allowing tool 50 to slide forward to the initial position wherein razor blade pieces 64 and 65 bear on the rear face of stop head 19. Depending on orientation with strap tail 22, pawl finger 73 (best shown in FIG. 7)of either shaped head 84 or shaped head 85 prevents withdrawal of strap tail 22. Carrier assembly 70 is then rotated in the free direction about cutter wheel assembly 51 which through drive flanges 58 and 59 transmits drag forces to strap tail 22. Said rotation of carrier assembly 70 about cutter wheel assembly 51 causes stop assembly 80 to be carried rearward until friction between external threads 82 and internal threads 78 builds to overcome the torsional stiffness of strap tail 22 halting thread travel. Strap tail 22 is lightly tensioned between strap head 19 and stop assembly 80 by said rotation. With strap tail 22 thus tensioned, strap 16 may be tightened by rocking tool 50 about strap head 19 within the plane formed by the loop of strap 16. In this manner tool 50 becomes a tightening lever using the rear face of strap head 19 as a fulcrum. Said rocking of tool 50 will pull strap tail 22 through strap head 19 reducing the tension on strap tail 22 between strap head 19 and stop assembly 80. To continue the efficient tightening of strap 16, light tension on strap tail 22 must be restored by again rotating carrier assembly 70 in the free direction about cutter wheel assembly 51. By resistance to the rocking motion of tool 50, the operator will determine the point at which sufficient tightening of strap 16 about a plurality of articles has been reached. When strap 16 is determined to be sufficiently tight, excess strap tail 22 may be cut off by rotating carrier assembly 70 in the direction which engages cutter wheel assembly 51, thereby bringing either or both razor blade pieces 64 and 65 into severing contact with said excess strap tail 22. In order to produce a clean cut flush with strap head 19 and avoid an undesirable strap tail burr, tool 50 should be returned to its initial position normal to strap head 19 and rotated first in the free direction to lightly retension strap tail 22 before cutter wheel assembly 51 is engaged. 
     While there have been shown and described and pointed out the fundamental novel features of the invention as applied to the preferred embodiments, it will be understood that various omissions and substitutions and changes of the form and details of the device illustrated and in their operation may be made by those skilled in the art, without departing from the spirit of the invention. For instance, incorporating additional functions for the tool, such as that of a cap for a pen.