Abstract:
A hand held tool for the tensioning and severing of cable ties, including reciprocating means for tensioning the cable tie tail, locking means to prevent further tensioning upon the attainment of a preselected tension level in the tie tail, and severing means to sever the tie tail from the cable tie head. The tool includes a tension adjustment system and an independent calibration mechanism.

Description:
RELATED APPLICATION 
       [0001]    This application claims the benefit of co-pending U.S. Provisional Patent Application Ser. No. 62/091,004, filed 12 Dec. 2014. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    The present invention relates to hand held tensioning and cutting tools, and particularly to an improved hand tool for tensioning and cutting cable ties. 
         [0003]    Cable ties are widely used in a variety of environments and applications. They may be used, for example, to bundle a plurality of elongate wires, cables, or other elongate articles. Cable ties may also be used to secure elongate articles to rigid structures or used as hose clamps, by way of example. Such cable ties typically include an elongate tail portion which is threaded through an integral head portion to encircle the articles to be bound and the tie tail is drawn through the cable tie head to tightly bind the elongate articles into a bundle. After the tie is tensioned around the bundle, the excess length of the tie tail which extends out of the head portion is then severed by the tool close to the head. Ties are often applied in high volumes and to precise tensions. 
         [0004]    One disadvantage of many presently available tie tensioning and severing tools is that those tools require an operator to apply an excessive force on their triggers which leads tool operator fatigue after only a relatively small number of cables ties have been installed by the operator. Additionally, many prior art tie tensioning and severing tools have their tool triggers mechanically linked to the tensioning and severing mechanisms in a manner that the actual tension attained in the cable tie immediately prior to severing of the cable tie tail varies with the position of the operator&#39;s grip on the trigger during operation of the tool. Tools which rely upon mechanical linkages often increase the tension in the cable tie above the preselected value immediately prior to severing due to the movement of the linkages during the tensioning operation. This can cause stretching, weakening or breakage of the tie during severing. 
         [0005]    The present invention has application to the cable tie tensioning and cut-off tools disclosed in U.S. patent application Ser. Nos. 13/534,791; 13/534,826; 13/534,877; 13/534,902; 14/532,619 and 14/532,637 owned by the same assignee and each incorporated herein by reference. 
       SUMMARY OF THE INVENTION 
       [0006]    The present invention is directed to a hand-held tensioning and severing tool which avoids the aforementioned shortcomings. 
         [0007]    In accordance with a principal aspect of the present invention, a selective tension adjustment system is provided in the form of an acme thread cam and knob for selectively changing the preselected tie tension to a selected tension value. 
         [0008]    Another object of the present invention is to provide a hand tool for tensioning and severing cable ties which includes rotatable selective tension adjustment means for rapidly and reliably selecting a number of preselected tension levels. 
         [0009]    An embodiment of the invention comprises a tensioning system for adjusting the tension imparted to a cable tie in a cable tie tensioning and cut-off tool, the cut off tool including a housing and a cable tie gripping mechanism, the tensioning system having a tension adjustment knob having at least one slot formed thereon and at least one spline formed therein; a ring member having at least one cog on a first side and at least one detent on a second side, the at least one cog being engagable with the at least one slot; a rotating cam having an external thread and at least one tessellated portion formed thereon, the at least one tessellated portion being engagable with the at least one spline; a fixed cam coupled to the housing and having an internal thread being engagable with the rotating cam external thread; a tension shaft having a first end, the first end being coupled to the rotating cam; and at least one tension biasing member coupled to the shaft and to the gripping mechanism. 
         [0010]    The tensioning system may further include a locking latch coupled to the housing and having at least one tooth engagable with the at least one detent and a protrusion affixed to the fixed cam, the protrusion being engagable with the at least one detent formed on the ring member. When engaged the locking latch prevents a disengagement of the at least one tooth and detent. 
         [0011]    The tensioning system further includes a calibration mechanism, the calibration mechanism having a thread being formed on a first end of the tension shaft and a calibration nut being located between the rotating cam and the tension adjustment knob, the nut including a threaded opening for receiving the first end of the tension shaft. The tension biasing member may comprise a spring, two springs or a plurality of springs. 
         [0012]    The tensioning system may further include a calibration tool having a working end. The calibration nut may have at least one slot formed therein whereby the calibration tool working end may be engaged with the at least one calibration nut slot. In another embodiment, the tension adjustment knob has an opening formed therein and further includes a removable cap covering the opening. In addition a plurality of ridges may be formed on the calibration nut, the ridges being engagable with groves formed on the rotating cam. In another embodiment, the tension adjustment knob has a recessed opening and the tension calibration nut is accessible through the opening. 
         [0013]    Indicia may be formed on or applied to the tension adjustment knob; the indicia correspond to incremental tension ranges and designated tension settings for the system. In addition the at least one detent and the at least one protrusion may provide a tactile indication of tension adjustment as the knob is rotated. Alternatively or concurrently, the at least one detent and the at least one protrusion may provide an audible indication of tension adjustment as well. 
         [0014]    Another embodiment of the invention comprises a tensioning system for adjusting the tension imparted to a cable tie in a cable tie tensioning and cut-off tool, the cut off tool including a housing and a cable tie gripping mechanism, the tensioning system having a rotatable tension adjustment knob coupled to a rotating cam; the rotating cam threadingly coupled to a fixed cam; the fixed cam coupled to the housing; a tension shaft having at least one tension biasing member coupled thereto, the tension shaft being attached to the fixed cam; and the tension shaft coupled to the cable tie gripping mechanism. A locking latch may be proved as described above to prevent desired movement of the tension adjustment knob all together or in desired increments. The increments may be relatively small or large as desired by the user. A similar calibration mechanism may also be provided to calibrate the force the cable tie tensioning and cut-off tool applies to a cable tie before cutting or severing the cable tie tail. 
         [0015]    These and other objects, features and advantages of the present invention will be clearly understood through a consideration of the following detailed description. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0016]      FIG. 1  is a perspective view of a cable tie tensioning and cut-off tool according to the present invention. 
           [0017]      FIG. 2  is a left side view of the tool illustrated in  FIG. 1 . 
           [0018]      FIG. 3  is a top view of the tool illustrated in  FIGS. 1 and 2 . 
           [0019]      FIG. 4  is a view similar to that of  FIG. 2 , but with a portion of the housing removed and showing the tensioning mechanism. 
           [0020]      FIG. 5  is a top perspective view of a control knob on the tool shown in  FIGS. 1-4  that provides tension adjustment. 
           [0021]      FIG. 6  is a bottom perspective view of the control knob illustrated in  FIG. 5 . 
           [0022]      FIGS. 7A-7C  are cross sectional views of the control knob illustrated in  FIG. 5  taken along lines  7 A- 7 A thereof, and showing further details of the form and function of the; control knob, operation of the control knob and showing movement of the associated parts. 
           [0023]      FIG. 8  is an exploded view of the control knob shown in  FIGS. 5-7C . 
           [0024]      FIG. 9  is a perspective view of a hold back fin shown in  FIG. 8 . 
           [0025]      FIG. 10  is a perspective view of a calibration tool for use with the present device. 
           [0026]      FIG. 11  is a fragmentary exploded view of the cams and calibration nut and showing engagement means. 
           [0027]      FIG. 12  is a bottom perspective view of a locking latch for use with the present device. 
           [0028]      FIG. 13  is a perspective view of the ring and tensioning knob for use with the present device. 
           [0029]      FIGS. 14-16  illustrate operation of the cable tie tensioning and cut-off tool shown in  FIGS. 1-4 . 
           [0030]      FIG. 17  is a view similar to that of  FIGS. 14-16 , but showing locking of the top latch. 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0031]    Although the disclosure hereof is detailed and exact to enable those skilled in the art to practice the invention, the physical embodiments herein disclosed merely exemplify the invention which may be embodied in other specific structures. While the preferred embodiment has been described, the details may be changed without departing from the invention. 
         [0032]    Referring now to the drawings and in particular to  FIGS. 1 and 2 , an embodiment of the cable tie tensioning and cut-off tool  10  incorporating the principles of the present invention is shown as having a housing  12  in the shape of a pistol or gun and having a handle or grip portion  14 , a barrel portion  16 , and a trigger  18 . The trigger  18  is located forwardly of the grip  14  and under the barrel portion  16  where it fits naturally in the hand of a user (not shown in these views). The tool  10  is typically used to install cable ties  20  (seen in phantom in  FIG. 2 ) around elongate bundles  22 , such as wire cable or the like. As mentioned earlier, cable ties are widely used in a variety of environments and applications, and may be used, for example, to bundle a plurality of elongate wires, cables, or other elongate articles  22 , as is shown in  FIG. 2 . However, it is to be understood that the tool  10  of the present invention may be used to secure cable ties  20  in other applications, such as to secure elongate articles to rigid structures or used as hose clamps (not shown), by way of non-limiting example. As illustrated, a tie  20  includes a head portion  24  and a tie tail portion  26 . The tool  10  grips the tail portion  26  of the tie  20  and pulls it through the head  24  until a predetermined tension is achieved. The tool  10  then locks the tension and automatically cuts off the excess tail portion  26  adjacent the head  24 . 
         [0033]    As seen in  FIG. 4 , a portion of one housing  12  sidewall has been cut away to show the opposite housing  12  sidewall and the internal parts and mechanism of the present tool  10 . The tool  10  generally contains the usual components for a tool of this type, including a reciprocating tension mechanism, located in the barrel portion  16  of the tool  10  (not shown); the tension mechanism includes a gripping mechanism  30 , for gripping the tail portion  26  of a tie  20 , and a locking mechanism, for locking the tension mechanism at a predetermined tension prior to activating a cutoff mechanism. In operation, the tensioning mechanism pulls the gripped tail portion  26  rearwardly to a predetermined tension. Upon reaching the predetermined tension, the locking mechanism locks the tension. A cutoff mechanism (not shown), also located at the forward end of the barrel portion  16 , activates to cause a blade member (not shown) to cut off the tie tail  26  closely adjacent the head portion  24 . The predetermined tension is set or adjusted by way of a tension adjustment mechanism located at the rear of the tool  10 , as will be discussed in detail. 
         [0034]    Tension Adjustment System 
         [0035]    The present tool  10  includes a novel tension adjustment mechanism, As will be seen, the tension control and adjustment mechanism of the present tool  10  functions to provide a controlled tension to the rear of the cutoff cam  36  (see  FIG. 4 ). This, in turn, determines the point at which the cutoff cam  36  pivots to actuate the locking mechanism and the cutoff mechanism, to thereby cut off a tie tail  26 . 
         [0036]    The tension adjustment system of the present device is simple to use and eliminates the use of two knobs, as in known devices, through the use of an acme thread cam action and knob, as will be discussed. The system further provides both incremental tension settings and predetermined, widely spaced settings. The widely spaced settings allow the user to quickly change the tension settings in a one-handed operation. A tension control mechanism according to the present invention may be seen particularly in the views of  FIGS. 5-8 . As illustrated, the tension control mechanism includes a U-bracket  38  positioned horizontally, and slidably moveable, within the housing  12  at the rear end of the barrel portion  16  of the tool  10 . The forward ends  40  of the U-bracket  38  are pivotally coupled to the rear end of the cutoff cam  36  by way of a tension pin (not shown) or other acceptable device, extending through the forward ends  40  of the U-bracket  38  and through a corresponding slot (not shown) in the cutoff cam  36 . The rearward end of the U-bracket  38  is biased toward the rear of the housing  12  by means of the inner and outer tension springs,  46 ,  48  respectively. The tension springs  46 ,  48  are adjusted by a tension nut  52 . A rotating cam  54  is coupled to a tension adjustment knob  56  by way of tessellated portions  58  which engage corresponding interlocking splines  60  in the adjustment knob  56 . The rotating cam  54  further includes a threaded portion  62  adapted to threadingly engage the internal threaded portion  70  of fixed cam  64  and its housing  66 . As the adjustment knob  56  is turned, the rotating cam  54  either draws the tension shaft  50  closer to the rear of the housing  12  or drives the tension shaft  50  farther from the rear of the housing  12  depending on the direction in which the adjustment knob  56  is turned. Accordingly, the tension applied by the U-bracket  38  to the cutoff cam  36  is increased as the adjustment knob  56  is turned so as to compress the tension springs  46 ,  48 , and is decreased as the adjustment knob  56  is turned to decompress the tension springs  46 ,  48 . 
         [0037]    With specific attention to  FIG. 8 , the tessellated portions  58  of the rotating cam  54  may be seen. The tessellated portions  58  mate with and slide on splines  60  located in the tension adjustment knob  56 . This interrelationship allows the threaded portion  62  to rotate and move longitudinally along the splines  60 , while the adjustment knob  56  remains stationary, thereby allowing the overall tool  10  length and tool ergonomics to remain constant throughout the adjustment range. 
         [0038]    With further attention to  FIG. 8 , incremental tension ranges may be seen to be provided by detents  270  on a ring member  214 . Protrusions  212  on a pusher  210  (see also  FIG. 9 ) ride in the detents  270 . As shown, the ring member  214  includes a first side  216  which includes the mentioned detents  270 , and a second side  218 . Preferably, the adjustment knob  56  includes indicia  68  to designate selected tension settings. The indicia  68  correspond to the incremental tension ranges. The second side  218  includes a plurality of widely spaced cogs  220 . The cogs  220  correspond to and engage with mating slots  222  on the adjustment knob  56  (see also  FIG. 13 ). The cogs  220 , in conjunction with the mating slots  222 , allow the tension adjustment system to be adjusted to predetermined settings independent from the incremental tension settings provided by the previously mentioned detents  270 . The cogs  220  and mating slots  222  allow the user to alternatively select tension settings that correspond to the cog  220  spacing. The tension settings that correspond to the cog  220  spacing are designed to provide a preset setting location for quick change of tension without requiring the user to manipulate the locking latch  74 , as will be described. While the present drawings illustrate three spaced cogs  220 , it is to be understood that the number and spacing of the cogs  220  may vary without departing from the present invention. 
         [0039]    As mentioned, the present tension adjustment system further includes capability to calibrate, hold and lock. A locking latch  74  is slidingly located on the housing  66  of the fixed cam  64 . As best shown in  FIG. 12 , the locking latch  74  includes a plurality of teeth  72  that engage with detents  270  on ring member  214 . As is seen particularly in the views of  FIGS. 7A-8 , the locking latch  74  includes a switch  76  and a locking pin  78 , seen as a screw in these views. Incremental tension adjustment using the locking latch  74  is illustrated in  FIGS. 16 and 7C . As viewed, to adjust tension, the hold switch  76  on the top of the tool  10  is moved in the direction of arrow D, to an unlocked position; the adjustment knob  56  is rotated in the direction of arrow A (see also  FIG. 7C ) to the desired tension setting; and the hold switch  76  is released to the lock position (see  FIG. 7A ). The precise tension setting is accomplished by rotating the adjustment knob  56  across the multiple discrete detent stops  270  on the ring  214 . As is seen in  FIG. 7C , as the adjustment knob  56  is rotated in the direction of arrows A, the detent stops  270  pass over the protrusions  212  on the pusher  210  to thereby bias the pusher spring  224  in the direction of arrow B. This action provides the user with both tactile and audible indications of the tension settings associated with the indicia  68 . If desired, the locking latch  74  may be locked to prevent inadvertent tension changes by moving the locking pin  78  from its stowed position to a locked position (see  FIG. 17 ). 
         [0040]    As seen in  FIGS. 7B and 15 , tension may be alternatively adjusted without the need to manipulate the locking latch  74 . As shown, a user may rotate the adjustment knob  56  in the direction of arrow C without manipulating the locking latch  74 . When a user rotates the adjustment knob  56  without manipulating the locking latch  74 , the ring member  214  moves in the direction of arrow E and biases the pusher spring  224  and locking latch spring  226  in the direction of arrow D. The user continues to exert torque on the adjustment knob  56  to overcome the bias of the springs  224  and  226  while the ring member  214  continues movement in the direction of arrow E, thereby disengaging the slots  222  from the cogs  220  and allowing the adjustment knob  56  to rotate until the user reengages an adjacent cog  220 . During adjustment, the slots  222  on tension adjustment knob  56  slip to ride over the second side  218  of the ring member  214 , until the next desired cog  220  is selected thereby moving the tension shaft  50  in the direction of arrow F and changing the tension to correspond with the spaced cogs  220  on the ring member  214 . 
         [0041]    Calibration 
         [0042]    The tension adjustment system may be calibrated at the point of manufacture or may be calibrated in the field. Calibration sets the base tension point from which the further tension adjustments, discussed previously, may be made. During calibration, a calibration tension tool  80  may be used. 
         [0043]    With specific reference to  FIG. 10 , a calibration tension tool  80  for use with the present device  10  may be seen. As seen, the calibration tension tool  80  includes a first side  180  and a second side  182 . As viewed, the first side  180  preferably includes a plurality of upstanding protuberances  184 . A second side  182  of calibration tension tool  80  includes an upstanding, elongate key device  186 . As shown, the key device  186  may further include at least one pin portion  188 . The first side  180  of calibration tool  80  may be used to remove the calibration cap  190 . The protuberances  184  engage corresponding detents  191  in the calibration cap  190  to allow the calibration tool  80  to twist off the calibration cap  190  when access is desired. When the calibration cap  190  is removed, and as seen in  FIGS. 10 and 11 , the key device  186  on the second side  182  of calibration tool  80  along with pin portions  188  engage the tension calibration nut  52  in corresponding slots  192 , The calibration tool  80  is then rotated in a direction to thereby rotate the tension nut  52  to a predetermined tension force. It is to be noted that rotation of the tension nut  52  may be in clockwise or counterclockwise direction, depending on whether the user wishes to set calibration at a higher or lower set tension force. Moreover, the calibration nut  52  may include a plurality of upstanding ridges  228  that are adapted to engage corresponding grooves  230  in the housing  66  of rotating cam  54  and fixed cam  64  (see  FIG. 11 ). The arrangement of cooperating ridges  228  and grooves  230  provides a secure interaction between the elements over time and thereby reduces undesired tension nut  52  rotation and resultant tension force change due to slippage caused by vibration or frequent adjustment. 
         [0044]    The foregoing is considered as illustrative only of the principles of the invention. Furthermore, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described. While the preferred embodiment has been described, the details may be changed without departing from the invention.