Abstract:
A banding material gripping mechanism and band tightening tool using the same are disclosed, wherein there is a reduced likelihood of the banding material buckling in the tool. The gripping mechanism includes gripping body and a banding material gripper component (“gripper”) that reciprocates within the gripping body for iteratively: (i) gripping the banding material so that a band being formed from the banding material can be tightened, and (ii) releasing the banding material so that the gripper can slide along the banding material as the gripping body moves forwardly over a further length of excess banding material in preparation for performing (i) again. The gripper has a banding material contacting portion with a shape that cooperatives with a slot provided within a banding material support platform of the gripping body such that during (i) above, the banding material is deformed into the slot thereby reducing a likelihood that (i) results in a hump in the banding material forwardly of the gripper that could prevent the gripper from effectively sliding over the banding material in (ii).

Description:
RELATED FIELD OF THE INVENTION  
       [0001]     The present invention is related to band tightening devices for use in banding objects, and in particular, for banding objects wherein the banding material has a reduced likelihood of buckling within such a band tightening device.  
       BACKGROUND  
       [0002]     Various embodiments of band tightening tools are known, wherein such tools are used for fixedly securing bands about objects. In particular, such bands may be composed of, e.g., a plastic or metal, and the objects may be, e.g., sensors, heat shields, cables, poles and pipes. In some known band tightening tools, such as the band tightening tool disclosed in U.S. Pat. No. 5,566,726, filed Jun. 2, 1994 fully incorporated herein by reference, there is a band gripping mechanism (also denoted a “tension block”) that repeatedly grips a banding material, and pulls portions of the banding material from about an object(s) being banded, thereby tensioning the banding material about the object(s). More particularly, during tightening of a band, such a band gripping mechanism is alternately: 
        (a) moved along a length of the banding material in a first (non-tensioning) direction to thereby reach a position on the banding material that can be gripped for subsequently pulling on the length of the banding material that is surrounding the object(s) being banded so that the band further tightens about the object(s), and     (b) once fully moved in the first direction, the gripping mechanism is then pulled in an opposite second (tensioning) direction whereby a “gripper” (such as a cylindrical pin having a cylinder axis parallel with a width of the banding material) securely grips the banding material so that the banding material is further tensioned about the object(s) being banded as the gripping mechanism is moved in the second direction.        
 
         [0005]     Such a gripper may be biased by a spring or other biasing devices to contact the banding material, at least at the commencement of the pulling of the gripping mechanism in the second direction. Moreover, such biasing must be of sufficient force to cause the gripper to securely grip the banding material. Additionally, as the gripper mechanism is pulled in the second direction, the gripping pin must apply a banding material gripping force that is sufficient to overcome any counterforce, from the band being tensioned, that the banding tool is capable of producing in the band. Accordingly, the gripper can deform the banding material in an area extending around where the gripper contacts the banding material during the band tensioning step (b) above. In particular, the banding material deformations can include depressions (and/or protrusions or raised portions) in the banding material immediately adjacent to the gripper. Moreover, when the gripping mechanism has moved its full extent in step (b) above (i.e., in the second direction) and reverses direction for moving in the first direction (i.e., step (a) above), the gripper must release its grip from the banding material. Thus, the gripping force on the banding material must be reduced at least enough so that the gripper slides over, or moves relative to, an additional length of the banding material as the gripper mechanism moves in the first direction. However, for the gripper to appropriately slide or move relative to the banding material requires that such deformed or raised portions of the banding material must not inhibit the relative movement of the gripper mechanism. In at least some circumstances, when the gripper attempts to move past such raised portions, the gripper contacts these portions with sufficient impact causing buckling of the banding material in the band tightening tool (i.e., between the gripping mechanism and the band being formed). Moreover, such buckling of the banding material within the band tightening tool can jam the tool thereby causing an operator to start the band tightening process over, and/or entirely replace the banding material being used to form the band.  
         [0006]      FIG. 1  is illustrative of the above described steps (a) and (b). In  FIG. 1  various portions of a prior art band tightening tool  18  are illustrated, and in particular, this figure shows two internal components of the band tightening tool: a gripping mechanism  20 , and spaced apart therefrom, an additional gripping assembly  24 , wherein the banding material  28  threads through both the mechanism  20  and the assembly  24 . The gripping mechanism  20  includes a gripping body or block  30  with a proximal end  32 , wherein the proximal end is relatively closer to the band  36  being formed about an object(s)  40  than the distal end  44  of the gripping body  30 . Note that the dashed outline shows the furthest movement of the proximal end in the first direction of step (a) above. The gripping body  30  further includes a platform  48  for supporting the banding material as it passes through the gripping body. The gripping body  30  also includes an opening  52  that inclines toward the platform  48  as the opening extends toward the proximal end  32  of the gripping body. The gripping mechanism  20  further includes a cylindrical gripping pin (or gripper)  56  that is moveable within the opening  52 . The gripping mechanism  20  additionally includes a biasing component (not shown) for biasing the gripping pin  56  in the direction of arrow  60 . Accordingly, when the gripping mechanism  20  moves in the direction of arrow  64 , the gripping pin  56  slides on the surface of the banding material  28 . However, when the gripping mechanism  20  is moved in the second direction (i.e., the direction of arrow  68 ), the gripping pin  56  moves toward the proximal end  72  of the opening  52  and frictionally binds between the banding material  28  and an opposed portion of the proximal end  72 , thereby gripping the banding material.  
         [0007]     The gripping assembly  24  includes an inclined opening  76  and a gripping pin  80  that is moveable therein, wherein the pin  80  is biased toward the proximal end  84  of the opening  76 . Thus during operation, in step (a), the pin  80  of the gripping assembly  24  frictionally binds between the banding material  28  and an opposed portion of the proximal end  84 , thereby gripping the banding material  28  so that a band tension counterforce in the direction of arrow  88  does not pull the banding material  28  from the band tightening tool  18  (which includes both the gripping mechanism  20  and the gripping assembly  24 ) as the gripping mechanism  20  moves in the direction of arrow  64 . Once the gripping mechanism  20  has completed its movement toward the gripping assembly  24 , in step (b) above, the mechanism reverses direction thereby causing the gripping mechanism to securely grip the banding material  20  and pull it in the direction of arrow  68  (as long as the force for moving the gripping mechanism  20  in the direction  68  overcomes any band tension counterforce in the direction of arrow  88 ). Since movement of the banding material  28  in the direction  68  causes the gripping pin  80  to release its grip on the banding material, additional banding material is pulled into the band tightening tool  18  thereby further tightening the band  36  about the object(s)  40 .  
         [0008]     However, since the gripping pin  56  can cause the banding material  28  to deform producing depressions  92  and/or raised portions  96 , when the gripping mechanism  20  commences to move in the direction of arrow  64 , such deformed portions of the banding material can prevent the gripping pin  56  from properly unbinding from the proximal end  72  of the opening  52 . Thus, as the gripping mechanism  20  moves toward the gripping assembly  24 , the banding material  20  may form a buckle  100  and jam the band tightening tool.  
         [0009]     Accordingly, it is desirable to enhance such a band tightening tool so that the above described buckling of the banding material does not cause the tool to jam. More particularly, it is desirable to substantially prevent such banding material buckling in the tool. The invention as described hereinbelow provides such an enhancement to a band tightening tool.  
       SUMMARY  
       [0010]     The present invention is a banding material gripping mechanism and band tightening tool or apparatus for using the same, wherein there is a reduced likelihood of the banding material buckling in the tool. In particular, the present invention performs the operations of steps (a) and (b) described in the Background section hereinabove, but performs these steps with novel configurations of the gripping body and the gripper that reduce banding material buckling. In particular, the gripping body includes a central recess, and two extended portions (also denoted “wings” herein) on parallel sides of the central recess and defining the walls of the recess. More specifically, the central recess is bounded by: (i) a platform surface for supporting or guiding the banding material as the steps (a) and (b) described in the Background section above are performed, and (ii) the two walls provided by the wings of the gripping body, wherein the platform surface is therebetween. Provided within the platform surface is a novel slot whose width and length are aligned, respectively, with the width and length of the banding material traversing the platform surface when the steps (a) and (b) are iteratively performed. The slot operably cooperates with a gripper having a novel configuration, wherein the gripper includes a banding material gripping portion shaped for deforming the banding material into the slot when a banding material deforming force is applied to the gripper. The banding material gripping portion has a shape that protrudes into the banding material a furthest extent substantially at banding material locations both in line with a length of the slot, and substantially at a proximal end of the slot (i.e., the slot end where the banding material first comes in proximity to the slot). Thus, when the banding material deforms into the slot, the energy that could otherwise result in a banding material raised portion in front of (i.e., proximally) of the gripper (as described in the Background section hereinabove) is now substantially directed into deforming the banding material into the slot. Moreover, in at least some embodiments, the shape of the gripping portion may be convex relative to a width of the banding material thus causing the banding material surface being contacted by the gripping portion to become concave, and such concavity further reduces the formation of such raised portions proximal of the gripper band material deforming area.  
         [0011]     It is also an aspect of the invention that such in slot banding material deformations are substantially adjacent to the proximal terminating end of the slot. Thus, such deformations can also serve as locks for further preventing the banding material from retracting from the band tightening tool to thereby relieve the band tightening tension.  
         [0012]     It is also an aspect of the present invention that the gripping mechanism of the present invention may be used in prior art band tightening tools as a replacement for prior art gripping mechanisms.  
         [0013]     Other features and benefits of the present invention will become evident from the accompanying figures, and their description including the Detailed Description hereinbelow. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0014]      FIG. 1  shows the components and operation of a prior art embodiment of the portion of a band tightening tool  18 , wherein this portion tightens a banding material  28  about one or more objects  40 .  
         [0015]      FIG. 2  shows an embodiment of the internal band tightening components of a band tightening tool  18   m  according to the present invention, wherein a novel gripping body  30   m  is employed for tightening the banding material  28  without buckling the banding material and jamming the band tightening tool  18   m.    
         [0016]      FIG. 3  shows a perspective view of the gripping mechanism  20   m.    
         [0017]      FIG. 4  shows a top view of the gripping body (equivalently gripping block)  30   m.    
         [0018]      FIG. 5  shows a side view of the gripping mechanism  20   m.    
         [0019]      FIG. 6  shows an end view of the gripping body  30   m.    
         [0020]      FIG. 7  shows a side view of the gripping mechanism  20   m  with a series of banding material  28  deformed portions  200  in the slot  198 . 
     
    
     DETAILED DESCRIPTION  
       [0021]      FIGS. 2 through 7  are illustrative of the present invention. Many of the components and/or features identified in these figures correspond to components and/or features of the prior art as illustrated in  FIG. 1  and described in Background section above. Accordingly, the components and/or features of the present invention that correspond with labeled components and/or features of  FIG. 1  are labeled with the same numeral in  FIGS. 2-7 . However, such components and/or features of the present invention are also further identified by a suffix of an “m” following each such numeral label to thereby indicate that such components and/or features may be enhanced and/or modified to more effectively provide the benefits of the present invention.  
         [0022]     Referring to  FIG. 2 , an embodiment of a band tightening tool  18   m  is illustrated, wherein this tool substantially reduces or entirely prevents the jamming of the tool due to the buckling of the banding material  28  discussed with reference to  FIG. 1 . The present embodiment of the tool  18   m  is pneumatic, wherein there are two pneumatic cylinders  120  and  124  for, respectively, tensioning the banding material  28  when forming a band, and actuating a tool head  134  that both cuts the banding material and forms a band lock for securing the tensioned band about the object(s) being banded. In particular, the pneumatic cylinder  120  provides the force for moving the clevis  138  in the direction of arrow  142 , and thereby causing the tensioning arm  146  to pivot about pin  150  so that the tensioning arm opposite end  154  moves in the direction of arrow  158 , and compresses the spring  162  via linkage  166 . Additionally, since the arm end  154  is pivotally secured via pin  170  to a gripping mechanism  20   m , this gripping mechanism is also urged in the direction of arrow  158  by the force from the pneumatic cylinder  120 . Thus, under the urging of this force, the gripping mechanism  20   m  pulls the banding material  28  (not shown in  FIG. 2 ) as described in step (b) of the Background section hereinabove. Subsequently, when the clevis  138  is fully extended in the direction of arrow  142 , the cylinder  120  pressure is reduced, and spring  162  reverses the pivoting movement of the tensioning arm  146  about the pin  150 . Thus, the clevis  138  moves in the direction opposite to arrow  142 , and the gripping mechanism  20   m  moves in the direction of arrow  64  thereby moving along a length of the banding material to reach a new position on the banding material for again gripping and inducing additional tension in the banding material.  
         [0023]     Referring to  FIGS. 3 through 8 , a novel embodiment of the gripping mechanism  20   m  according to the present invention is illustrated. The gripping mechanism  20   m  includes a gripping body or block  30   m  with a proximal end  32   m  and distal end  44   m , wherein, when assembled within a band tightening tool (e.g., tool  18   m ), the proximal end  32   m  is relatively closer to a band (e.g., band  36  of  FIG. 1 ) being formed about an object(s) than the distal end  44   m . The gripping body  30   m , in turn, includes a central recess  180  that extends from the proximal end  32   m  to the distal end  44   m . The recess  180  is bounded by a first wing  184  and a second wing  188 , wherein in at least one embodiment, the wings  124  and  128  are mirror images of one another. The recess  180  is also bounded by a platform  48   m , wherein the platform extends between the wings  184  and  188 , and also extends from a more proximal end  190  ( FIG. 4 ) to a more distal end  192 . The platform  48   m  retains the banding material  28  within the gripping body  30   m  as the banding material passes therethrough, and is used in gripping the banding material  28 . As best shown in  FIG. 4 , the platform  48   m  includes: 
        (i) a banding material ramp  194  (see  FIGS. 3 and 5  as well) for assuring that a free end of the banding material  28  enters the recess  180 ,     (ii) a surface  196  for supporting and/or contacting the banding material  28  as it passes through the recess  180 , and     (iii) a slot  198  substantially in a center area between the wings  184  and  188 , wherein the slot is for receiving a deformed portion  200  ( FIG. 7 ) of the banding material  28  resulting from a gripping of the band material by a gripper  56   m  (described hereinbelow). Moreover, note that the slot  198  has a proximal end  202  and a distal end  204 , wherein the slot proximal end  202  is relatively closer to the gripping body proximal end  32   m  (but as illustrated, the slot proximal end may be offset distally from the proximal end  32   m ). Additionally, since each deformed portion of the banding material  28  moves from the slot proximal end  202  toward the distal end  44   m  as the excess banding material taken from a band being formed, the slot  198  extends to the distal end  44   m  of the gripping body  30   m , and more particularly, the slot distal end  204  extends through the end  192  of the platform  48   m  and its surface  196 .        
 
         [0027]     The surface  196  extends from the ramp  194  to the distal end  192  of the platform  48   m . The surface  196  includes a gripping area  208  generally identified by the shaded area of  FIG. 4 , wherein this area is where the gripper  56   m  grips the banding material  28 . More specifically, the gripping area  208  is between the ramp  194  and the slot proximal end  202 . However, in some embodiments, the slot  198  may extend into the gripping area  208 , e.g., depending on the shape of the slot  198  and/or the shape of the gripper  56   m.    
         [0028]     The gripping body  30   m  also includes a bore  212  ( FIGS. 2 and 3 ) that extends completely through both the wings  184  and  188  of the gripping body. The bore  212  is the retainer for the pin  170  ( FIG. 2 ) that operably attaches the tension arm  146  to the gripping body  30   m.    
         [0029]     The gripping body  30   m  further includes at least one (and preferably two mirror image) openings  52   m  in the wings  184  and  188 , wherein each of these openings inclines toward the platform  48   m  (i.e., the surface  196 ) as the opening extends toward the proximal end  32   m  of the gripping body. Note that the angular range of this inclination may be in a range of 25 to 45 degrees relative to, e.g., the surface  196 , and more preferably 30 to 40 degrees, and most preferably about 35 degrees. Each of the openings  52   m  has a profile of an elongated circle having a circular proximal end  72   m , and a distal end  214 , each with a same diameter. The proximal end  72   m  of each opening  52   m  may extend to or traverse into the surface  196 , and the proximal end  72   m  may be closer to the proximal end  32   m  of the gripping block than is the slot proximal end  202 .  
         [0030]     As mentioned above, the gripping mechanism  20   m  also includes a gripper  56   m . An embodiment of the gripper  56   m  is shown in  FIG. 3 . The gripper  56   m  may include mirror image cylindrical end portions  220  and  224  as well as a central truncated spherical portion  228 . The end portions  220  and  224  are connected to the spherical portion  228  by a pair of truncated generally conical portions  232 . Note, that the gripper  56   m  may be machined from a single metal cylinder having its central axis  234  coincident with the central axes of the cylindrical end portions  220  and  224 , and having a diameter substantially identical to the diameter of these end portions  220  and  224 .  
         [0031]     When the gripper  56   m  is provided within the gripper block  30   m , each of the cylindrical end portions  220  and  224  resides within one of the openings  52   m  such that the spherical portion  228  is positioned substantially midway between the wings  184  and  188 . Note that the diameter of the end portions  220  and  224  is only slightly smaller than the diameter of the proximal and distal ends  72   m  and  218  of the openings  52   m . However, the diameter difference is effective for allowing each of the cylindrical end portions  220  and  224  to substantially freely slide within its opening  52   m.    
         [0032]     The gripping body  30   m  further includes a pair of gripper biasing recesses  216 , one in each of the wings  184  and  188 . Within each wing, its biasing recess  216  is generally cylindrical in shape, closed to the central recess  180 , and open on the side of the wing that is opposite the wing side facing the central recess. Moreover, the proximal end  218  of each biasing recess  216  opens into the distal end  214  of the adjacent opening  52   m  in the same wing. Additionally, each biasing recess  216  may be of sufficient length (between its proximal end  218  and its distal end  222 ) for effectively seating a biasing component such as compression spring  240  ( FIG. 2 ) for biasing the gripper  56   m  in the direction of arrow  60 . Thus, since the biasing component in each of the recesses  216  provides substantially the same compressive resistance to a corresponding one of the cylindrical end portions  220  and  224 , and since there is a relatively small tolerance (in the traverse directions to arrow  60 ) between each opening  52   m  and its contained cylindrical end portion, the gripper&#39;s central axis  234  remains substantially parallel to the surface  196  and any banding material  28  provided therebetween.  
         [0033]     Thus in operation, each of the cylindrical end portions  220  and  224  of the gripper  56   m  is provided in one of the openings  52   m  so that these end portions can slidably move within their corresponding openings  52   m . In particular, the gripper  56   m  is able to at least move (relative to the gripping block  30   m ) between: (1) a “released state”, wherein the truncated spherical portion  228  slides on the surface of the (any) banding material  28  (when the gripping block  30   m  moves the direction of arrow  64 ), and (2) a “gripping state”, wherein the cylindrical end portions  220  and  224  move synchronously toward the proximal ends  72   m  of the openings  52   m  and the spherical portion  228  grips the (any) banding material  28  provided on the gripping area  208 . More precisely, in the released state, the gripper  56   m  is positioned generally at location  244  ( FIG. 5 ) wherein it slides along the banding material  28  that is sandwiched between the truncated spherical portion  228 , and a portion of the slot  198  distal to its proximal end  202 . However, when the gripping block  30   m  reverses direction (thereby moving in the direction of arrow  68 ), the gripper  56   m  continues to move in the direction of arrow  64  (at least relative to the gripper block) due to: (a) the inertia of the gripper, (b) the biasing component, and/or (c) the frictional pull from the banding material  28  attempting to relieve the band tightening tension. Accordingly, a substantially increased force is exerted on the truncated spherical portion  228  to force it into the banding material  28  (due to the inclination of the openings  52   m  relative to the platform surface  196 ). The increased force corresponds with the spherical portion  228  overlying the slot proximal end  202  (or equivalently, the spherical portion forcibly moving into the surface of the banding material along an extent of the banding material whose opposite side is substantially adjacent to the slot proximal end). Thus, as the spherical portion  228  forcibly travels into the banding material  28  surface, the portion  228  effectively deforms or pushes the banding material  28  into the slot proximal end  202  thereby creating a deformed portion  252  in the slot  198  as shown in  FIG. 7 . Alternatively stated, the surface of the banding material  28  contacted by the increased force on the spherical portion  228  deforms to conform to the contour of the curvature of the spherical portion  228 , and since the circumference  248  ( FIG. 3 ) of the spherical portion extending furthest from the central axis  234  is substantially aligned with the central longitudinal axis  248  ( FIG. 4 ) of the slot  198 , the banding material is effectively pushed into the slot  198  near or at its proximal end  202 . Furthermore, each deformed portion  252  of the banding material  28  in the slot  198  may act much like a temporary band lock when it is against the slot proximal end  202 . Thus, the banding material  28  is less likely to slip from the gripper  56   m  than prior art versions thereof.  
         [0034]     In one preferred embodiment, the slot  198  has depth  256  ( FIG. 5 ) that is at least equal to the thickness of the “t” ( FIGS. 2 and 7 ) of the banding material  28 . Moreover, the width  260  ( FIG. 4 ) of the slot  198  may be in the range of 40% to 60% of the width “w” ( FIG. 3 ) of the banding material  28 . Furthermore, the ratio of the slot depth  256  to its width  260  may be about 0.2. Additionally, the spherical portion  228  may have a diameter of at least the width  260  of the slot  198 .  
         [0035]      FIG. 7  shows a side view of the gripping mechanism  20   m  wherein the gripper  56   m  is in the process of creating a deformed portion  252  in the slot proximal end  202 , and wherein the figure also shows previously created deformed portions  252  that have moved some length through the extent of the slot  198 . Note that since the slot  198  extends to the distal platform end  192  ( FIG. 4 ), the banding material downstream (i.e., distally) from gripping area  208  tends to remain in contact with the platform surface  196 , and thus freely slides between the platform  48   m  and the pin  170 .  
         [0036]     Various modifications of the above-described gripper mechanism  20   m  are also within the scope of the invention. For example, the spherical portion  228  may have a larger diameter. That is, a diameter substantially equal to the width “w” of the banding material  28 , and large diameters are also within the scope of the invention. It is also contemplated that the spherical portion  228  may be replaced with a portion having a different shape than a sphere. For example, an ellipsoid (e.g., with its major axis aligned with the central axis  234 ) may be used. Alternatively, a cylinder may be used, wherein the cylinder is oriented (relative to the central axis  234 ) in the same manner as the end portions  220  and  224 , and, wherein this cylinder has a thickness (along the central axis  234 ) of less than the width  260  of the slot  198 . Furthermore, the slot  198  need not have a rectangular cross section as shown in  FIG. 6 . For example, the slot cross section may be trapezoidal, wherein the longer of the parallel sides corresponds with the opening of the slot  198  into the surface  196 . Moreover, there may be a replacement for the spherical portion  228  that has similar but a reduced or offset trapezoidal profile such that the difference between the trapezoidal slot cross section and the trapezoidal profile is related to the thickness “t” of the banding material  28 .  
         [0037]     Regardless, of the shape of the band deforming portion  228  and the cross section of the slot  198 , it is within the scope of the present invention that the gripper  56   m  deforms the banding material  28  in a manner that such any raised portion of the banding material  28  is substantially reduced over such raised portions that are produced by, e.g., the prior art embodiments discussed in the background section hereinabove. For instance, the present invention precludes upstream (i.e., more toward a band being created) creation of a buckle  100  ( FIG. 1 ). In particular, one or more of the following techniques may be used to preclude such buckles: 
        (1) Provide deformations in the banding material  28  that are curved across the width “w” of the banding material  28  so that the banding material is, e.g., concave across its width; and     (2) Provide deformations in the banding material  28  wherein the deformations reside substantially in the slot  198 .        
 
         [0040]     Additionally, it is also within the scope of the present invention to provide two or more slots  198  together with a corresponding deforming portion  228  of the gripper  56   m , wherein the deforming portion  228  has a shape effective for providing at least one of (1) and (2) above for a plurality banding material  28  width extents. Thus, e.g., there may be two slots  198  spaced apart so that they are near the edges of the banding material  28 , and the deforming portion  228  may be shaped so as to have a profile substantially similar to a FIG. “ 8 ”.  
         [0041]     The foregoing description of the present invention has been presented for purposes of illustration and description. Furthermore, the description is not intended to limit the invention to the form disclosed herein. Consequently, variations and modifications commensurate with the above teachings, and the skill or knowledge of the relevant art, are within the scope of the present invention. The embodiments described hereinabove are further intended to explain the best mode(s) known for practicing the invention and to enable others skilled in the art to utilize the invention in such, or other, embodiments and with various modifications required by their particular applications or uses of the present invention. It is intended that the appended claims be construed to include alternative embodiments to the extent permitted by the prior art.