Abstract:
A band tensioning tool is provided that includes an easily replaceable blade and knife. More specifically, a banding apparatus is provided that does not require that a maintenance cover be removed to gain access to a knife, a front gripper, and a blade. This feature reduces tool head height, and the blade is interconnected to the tool head as opposed to being contained within the tool head and supported in a cantilevered manner.

Description:
[0001]    This application claims the benefit of U.S. Provisional Patent Application Ser. No. 61/595,968, filed Feb. 7, 2012, the entire disclosure of which is incorporated by reference herein. 
         [0002]    This application is also related to abandoned U.S. Patent Application Publication No. 2005/0166990, filed Aug. 4, 2005, which is incorporated by reference herein. This application is also related to U.S. Pat. No. 7,650,680, filed Oct. 17, 2005, which is also incorporated by reference herein. 
     
    
     FIELD OF THE INVENTION 
       [0003]    Embodiments of the present invention are generally related to a tensioning tool for banding objects, and in particular, a banding tool with an improved band gripping mechanism. 
       BACKGROUND OF THE INVENTION 
       [0004]    Band tensioning tools are used for fixedly securing plastic or metal bands about objects. The objects secured by the bands may include sensors, heat shields, cables, poles, signage, and pipes. For example, the band tightening tool of U.S. Pat. No. 5,566,726, which is incorporated by reference herein, employs a band gripping mechanism (also denoted a “tension block”) that repeatedly grips and tensions a band about an object(s) being banded. To tension a band, the tension block is first moved along a length of the band in a first direction generally toward the object(s) being banded. The tension block then engages the band and moves generally away from the objects being banded to incrementally tension the band. The tension block grips the band with a cylindrical pin having an axis that is oriented along the width of the band. The cylindrical pin may be biased by a spring, or other biasing device, to ensure firm engagement with the band when the tension block is pulled generally away from the object(s) being banded. After the tension block has moved its full extent away from the object(s) being banded, the tension block is released from the band so that it can be moved to another location on the band to begin another incremented tension cycle. When the tension block is moved, band tension is maintained by a front gripper that selectively contacts the band between the tension block and the objects being banded. 
         [0005]      FIG. 1  shows a band tightening tool  2  of the prior art and illustrates the tensioning steps described above. More specifically, the tension block  4  and the front gripper  8  spaced therefrom. The band  12  is threaded through both the tension block  4  and the front gripper  8 . The tension block  4  includes a proximal end  16  which is closer to the object(s) being banded  20  than a distal end  24 . The dashed outline of the tension block  4  represents the movement of the proximal end  16  towards the objects  20 . The tension block  4  further includes a platform  28  that supports the band  12  as it passes through the tension block  4 . The tension block  4  also includes a lateral opening  32  that inclines toward the platform  28  toward the proximal end  16  of the tension block  4 . The tension block  4  further includes a gripping pin (or gripper)  36  that is operably positioned and movable within the opening  32 . The pin  36  is biased by a biasing member (not shown) that moves the gripping pin  36  in the direction of arrow  40  to firmly engage the band. When the tension block  4  moves in the direction of arrow  44 , the gripping pin  36  is not biased and is able to slide on the surface of the band  12 . However, when the tension block  4  is moved away from the objects  20  (i.e., in the direction of arrow  48 ), the gripping pin  36  moves toward a proximal end  52  of the opening  32  and frictionally engages and grips the band  28 . 
         [0006]    The front gripper  8  also includes an inclined lateral opening  56  and a gripping pin  60  that moves within an opening  76 . The gripping pin  60  is biased toward a proximal end  64  of the opening  56 . When the tension block  4  is not tensioning the band  12 , i.e., moving in the direction of arrow  44 , the gripping pin  60  of the front gripper  8  frictionally engages the band  12  so that it is not slackened by a band tension counterforce acting in the direction of arrow  68 . Once the tension block  4  has completed its movement toward the front gripper  8 , it reverses direction, thereby causing the pin  36  to securely engage the band  12  and pull it in the direction of arrow  48 . Movement of the band  12  in the direction of arrow  48  causes the gripping pin  60  to disengage from the band  12 , thereby allowing the band  12  to be pulled into the band tightening tool  2 . 
         [0007]    After the tension block and the front gripper perform their respective portions of tensioning the band and maintaining band tension, the band is severed and clamped. A stationary blade is provided beneath the front gripper and a movable knife is provided forward of the front gripper. The knife moves relative to the blade to sever a band positioned therebetween. More specifically, once the desired band tension is achieved, a linkage is moved that moves the knife closer to the blade which compresses the band to eventually sever the same. The gap between the knife edge and the blade edge is preferably maintained within a predetermined tolerance which will ensure that the bands are cut in the most efficient manner, even after many cutting cycles. 
         [0008]    In operation, downward pressure from the knife is transmitted through the band and stresses the edge of the blade. This pressure is increased because the distance between the blade edge and the blade attachment, i.e., load reaction point, is not ideal. Cutting will eventually weaken the blade and cause it to yield or fracture. Unfortunately, the rate and mode of failure is unpredictable. For example, the blade may fail after 100, 200, or 1000 bands are tensioned. When blades fail, the tools are shipped from the end user to the factory for blade and/or knife replacement, which is expensive, costly, and time consuming. Furthermore, gaining access to the blade or the knife is time consuming and complicated. 
         [0009]    Blade support of prior art tools is not ideal, which increases blade damage. The primary failure mode is blade edge degradation and, in some instances, fracture. More specifically, the blade of prior art tools is rotatably interconnected to a tool head. Further, the blade of some prior art tools possesses an internal edge that engages the tool head to react loads being generated at an external edge of the blade when the knife contacts the band positioned therebetween. This complex design came from a desire to provide a blade with two edges such that when one was damaged, the blade could be removed and rotated to place the previously non-used blade adjacent to the knife. 
         [0010]    Furthermore, the knife of the prior art tools does not travel in a smooth, continuous manner, thus the gap between the knife and the blade is often increased or decreased which affects the performance of the cutting operation and which can add additional load to the blade. 
         [0011]    Another drawback of the prior tool is related to the tool head. More specifically, the tool head must accommodate the front gripper, the blade, and the knife and is structurally weak because it is machined with large pockets to accommodate these components. 
       SUMMARY OF THE INVENTION 
       [0012]    It is one aspect of embodiments of the present invention to provide a band tensioning tool with an easily replaceable blade and knife. More specifically, one embodiment does not require that a maintenance cover be removed to gain access to a knife, a front gripper, and a blade. In this embodiment, the blade is interconnected beneath the tool head by way of four fasteners. For example, M4 screws with 3 mm hex key may be used to interconnect the blade to the tool head. Such fasteners may be exposed to about 2000 pounds of axial tension before fracture. This improvement over the prior art tool reduces tool head height by about 0.110 inches, and the blade is interconnected to the tool head as opposed to being contained within the tool head and supported in a cantilevered manner. 
         [0013]    Furthermore, the tool head of one embodiment has reduced wear surfaces such that the tool head does not experience wear from loads generated by the front gripper. As a result, the material selection of the tool head is not critical. This improvement over the prior art increases the safety factor of the tool and, thus, reduces the need for repair and the costs therefore. The blade of one embodiment has three wear surfaces and is a main wear part. However, the cutting blade is much stronger than those of the prior art as they are supported near the cutting edge, i.e., the knife contact point. As a result, the blade is strained to a lesser degree during the cutting operation. To further facilitate interconnection of the blade to the tool head, two ⅛ inch alignment dowels may be used that are able to withstand about 3,000 lbs of shear force. 
         [0014]    It is another aspect of the present invention to provide a knife that moves in a smooth and stable manner. More specifically, the tool head of embodiments of the present invention has a rectangular channel that works in conjunction with a similarly-shaped outer surface of the knife to prevent knife rotation, which better simulates a cutting die. 
         [0015]    As briefly mentioned above, it is another aspect of the present invention to provide a front gripper that is interconnected to the tool head in a more efficient manner. As will also be appreciated upon review of the figures, the front gripper is simplified. Further, the front gripper utilizes a ball as opposed to a pin to engage the band. When the tension block travels away from the clamp, it grips the band and tensions the band. Once the end of stroke is reached, the tension block and the band moves in the opposite direction towards the objects being clamps. The front gripper prevents excessive band retraction or loosening by engaging the band and applying a downward force onto the band that increases as a function of band retraction. For example, in one embodiment, the retention force applied by the front gripper rises exponentially the more the band moves towards the objects being bundled. The gripping ball engages the band until there is sufficient downward force to wedge the band between a ball and an upper surface of the blade, a mechanism similar to that employed by ball locks of the art. When a subsequent tensioning step is initiated, i.e., when the tension block re-engages the band to begin another tensioning cycle, the front gripper swings in the direction of the tension block and is released. This interaction between the front gripper and tension block prevents band recoil in the time period between front gripper disengagement and re-engagement. The force required to release the front gripper is reduced due to the ability of the gripping ball to spin in an opposite direction when contacted by the tension block, which helps the front gripper to move out of locking position. 
         [0016]    The front gripper of one embodiment is covered by a maintenance cover that is much simpler and easier to remove and install than those of the prior art. 
         [0017]    It is another aspect of the present invention to provide a front gripper that can be used with prior art tools. That is, the pneumatic system of existing tools can be combined with a tool body assembly that employs the front gripper as contemplated by one embodiment of the invention. 
         [0018]    It is another aspect of the present invention to provide a scalable front gripper. More specifically, as one of skill in the art will appreciate the blade and knife configurations as described herein, for example, may be incorporated into a hand tool as opposed to a pneumatically driven tool as shown in the drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0019]      FIG. 1  shows the components and operation of a prior art band tensioning tool; 
           [0020]      FIG. 2  is a partial perspective of the prior art band tensioning tool; 
           [0021]      FIG. 3  is a perspective view of a front gripper of the prior art; 
           [0022]      FIG. 4  is a cross-sectional view of  FIG. 3 ; 
           [0023]      FIG. 5A  is a perspective view of the front gripper of one embodiment of the present invention; 
           [0024]      FIG. 5B  is a perspective view of the front gripper of one embodiment of the present invention; 
           [0025]      FIG. 5C  is an exploded perspective view of the front gripper of one embodiment of the present invention; 
           [0026]      FIG. 6  is a cross-sectional view of  FIG. 5 ; 
           [0027]      FIG. 7  is a side elevation view of a front portion of the band tightening tool wherein a cover has been removed for clarity so that the head, front gripper, tension block and related components are shown; 
           [0028]      FIGS. 8A-8G  show the band tightening tool of one embodiment of the invention; 
           [0029]      FIG. 9  is an exploded perspective view of  FIG. 8F ; and 
           [0030]      FIG. 10  shows the components in operation of a band tightening tool of one embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0031]      FIGS. 5A-8G  are illustrative of one embodiment of the present invention. The components and/or features identified in  FIGS. 5-8  work in a similar fashion as the prior art tool shown in  FIGS. 1 and 2 . For example, pneumatic drives  120 ,  124  and tension block  4  of the prior art tensioning tool shown in  FIG. 1 , or facsimiles thereof, may be used with the front gripper of embodiments of the present invention. In other words, front gripper  612  of the present invention may be substituted for front gripper  8  of the prior art. To understand the structure and workings of the front gripper, which, among other aspects of the present invention, constitute an improvement to the prior art, a brief discussion of the prior art tensioning tool is required. 
         [0032]    Referring to  FIGS. 1 and 2 , an embodiment of a band tensioning tool  2  is shown. The tool  2  employs a pneumatic cylinder  120  for tensioning the band and a pneumatic cylinder  124  for actuating a knife. The pneumatic cylinder  124  by way of linkages causes the band to be cut and forms a band lock for securing the tensioned band about the object(s) being banded. More specifically, the pneumatic cylinder  120  provides the force for moving a clevis  138  in the direction of arrow  142 , which causes a tensioning arm  146  to pivot about pin  150 . Pivoting the tension arm  146  causes an opposite end  154  of the tensioning arm to move in the direction of arrow  158  to compress a spring  162  via linkage  166 . This movement also urges the tension block  4  in the direction of arrow  158  which pulls the banding material described above. 
         [0033]    When the clevis  138  is fully extended in the direction of arrow  142 , the cylinder  120  pressure is reduced and spring  162  forces the tensioning arm  146  to pivot about the pin  150 . This movement of the tension arm  146  causes the clevis  138  to move in the direction opposite to arrow  142 , which moves the tension block  20  in the direction of arrow  44  to reach a new position on the band for re-gripping and inducing additional band tension. Movement of the pneumatic cylinder  124  moves linkages interconnected to a knife, which will be described below. 
         [0034]    The prior art tool head  500  and the tool head  600  of one embodiment of the present invention are compared in  FIGS. 3-6 . In  FIGS. 3-6  reference numbers in the five hundreds (5xx) refer to the prior art front gripper and surrounding components and reference numbers in the six hundreds (6xx) refer to the front gripper of one embodiment of the present invention and surrounding components. The tool heads include a linkage  504 ,  604  that is rotatably interconnected via a pin  508 ,  608  to a front gripper. As described above, the front gripper  512  of the prior art includes a gripping pin  516  that selectively engages a band that is inserted between a knife  520  and a blade  524 . The new front gripper  612 , conversely, includes a ball  616  for selectively engaging a band that is placed within a gap  652  between the blade  624  and the bottom surface  628  of the tool head  600 . 
         [0035]    The knife  620  of embodiments of the present invention has a square or rectangular profile that slides within a complimentary channel  632  in a knife housing  636  that is integrated into the tool head  600 . The knife  620  may also include a pin  640  that is used to place a locking dimple in the band. 
         [0036]    FIGS.  3  and  5 A- 5 C show the bottom surface of the blade  524 ,  624  and the interconnection of the blade  524 ,  624  to the tool head  500 ,  600 . Here, the prior art blade  524  is shown rotatably interconnected to the tool head  500  via a pin  544  that is attached to sidewalls  548  of the tool head  500 . Forces acting on the blade  524 , which are generated by the knife  520 , will be reacted by the pin. Forces will also be transmitted through the pin  544  to the sidewalls  548  of the tool head, which often weakens or damages the same. 
         [0037]    Embodiments of the present invention address this drawback of the prior art. By employing a blade  624  that is interconnected via a plurality of fasteners  648  to the bottom surface  628  of the tool head, i.e., not rotatably interconnected to the head. This interconnection method is stronger and more stable than the prior art method. The blade  624  is separated from the bottom surface  628  of the tool head to provide an opening  652  for receipt of a band. Here, the knife  632  is shown as having a rectangular or square profile that slides within a complimentary knife housing  636  that is integrated into the tool head  600 . A cutting edge  656  of the knife is positioned about 0.004 inches from a blade edge  660 , a dimension that is maintained to a higher degree than that of the prior art because the blade  624  does not move and weaken after repeated cutting cycles. 
         [0038]      FIG. 7  shows a front portion of a band tensioning tool that can be integrated to pneumatic cylinders or retrofitted onto pneumatic cylinders ( 120 ,  124  of  FIG. 2 ) of the prior art tool. In operation, a first pneumatic cylinder  120  is actuated to pull the band about 0.38 inches in the direction of arrow  68 . As this is being done, the front gripper  612  is positioned in such a way to allow a band, which is positioned between the blade  624  and the knife  620 , to be moved in the direction of arrow  68 . After the first pneumatic cylinder  120  reaches its travel limit, the second pneumatic cylinder  124  is actuated to move the knife  620  adjacent to the blade  624  to sever the band. 
         [0039]    As the tension block  20  moves to tension the band, the ball  616  engages the band, thereby preventing recoil as the tension block is picked up and moved to another location on the band. After the tension block  4  is in place it begins to engage the band to perform another incremental tension step and the front gripper is disengaged as described above. 
         [0040]    While various embodiments of the present invention have been described in detail, it is apparent that modifications and alterations of those embodiments will occur to those skilled in the art. However, it is to be expressly understood that such modifications and alterations are within the scope and spirit of the present invention, as set forth in the following claims. Further, the invention(s) described herein is capable of other embodiments and of being practiced or of being carried out in various ways. In addition, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. The use of “including,” “comprising,” or “having” and variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items.