Abstract:
An electrically powered strapping tool for tensioning and forming a sealless joint in overlapping sections of steel strap around a load includes a body having a foot, a tensioning assembly operably mounted to the body, the tensioning assembly having an electrically powered motor and a tensioning wheel operably connected to the tensioner motor. The tool includes a sealing assembly operably mounted to the body, the sealing assembly having an electrically powered motor and a sealer operably connected to the electrically powered motor. A control system controls operation of the tensioning assembly and the sealing assembly to operate the strapping tool in an automatic mode in which the tensioning assembly and the sealing assembly are sequentially actuated by a single action of the control system by an operator, and in a manual mode in which the tensioning assembly and the sealing assembly are sequentially actuated by multiple actions of the control system by the operator.

Description:
[0001]    CROSS-REFERENCE TO RELATED APPLICATION DATA 
         [0002]    This application claims the benefit of and priority to U.S. Provisional U.S. Patent Application Ser. No. 62/026,865, filed Jul. 21, 2014, the disclosure of which is incorporated herein in its entirety. 
     
    
     BACKGROUND 
       [0003]    Strapping tools or strappers come in a wide variety of types, from fully manual hand tools to automatic, table-top machines. Strapping tools can be designed and intended for use with different types of strap or strapping materials, such as metal strapping or plastic/polymeric strapping. Strappers for metal strapping materials can be automatic table-top or hand-held devices that are configured to seal the strap onto itself. The sealing function can be performed using a sealless configuration by forming interlocking keys in overlapping courses of the strap, or by applying a seal that is positioned over and crimped onto the overlapping strap courses. 
         [0004]    There are two types of known hand-held devices for steel strap: manual tools that require an operator to exert one or more forces to tension the strap and form the seal; and pneumatically operated tools that perform the tension and sealing functions by actuation of one or more pneumatic motors. The manual tools can be fatiguing to operate for long periods of time and may be difficult to maneuver and manipulate in certain instances, for example when the seal is formed on the side of a package or load. Moreover, manual sealing typically requires multiple tools to tension the strap, form the seal and cut the sealed strap from its source. 
         [0005]    Pneumatic tools, such as that disclosed in Crittenden, U.S. Pat. No. 6,079,457, commonly assigned with the present application and incorporated herein in its entirety by reference, function well; however, they require a source of compressed gas, such as air, and thus necessitate the use of hoses, compressed gas fittings and the like for operation. As such, the use of pneumatic tools may be limited in certain applications where, for example, the strapping operations are carried out at different locations throughout a manufacturing facility. Moreover, pneumatic tools employ pneumatic motors which can be costly, and pneumatic circuits which can be complex and require casting and machining operations in the manufacture of pneumatic circuit modules. 
         [0006]    Accordingly, there is a need for a powered strapping tool that functions to tension strap around a load, form a seal in the overlapping courses of strap material and cut the sealed strap from its source. Desirably, such a tool is self-contained, is electrically and/or battery powered, and is thus portable and can be used throughout a facility at any location. More desirably still, such a tool can be used in a variety of operating modes. 
       SUMMARY 
       [0007]    Various embodiments of the present disclosure provide a strapping tool for tensioning and forming a sealless joint in overlapping sections of steel strap around a load that includes a body having a foot, a tensioning assembly operably mounted to the body and a sealing assembly operably mounted to the body. The tensioning and sealing assemblies have electrically powered motors. 
         [0008]    A tensioning wheel is operably connected to the tensioner motor and a sealer is operably connected to the sealer motor. The tool includes a control system for controlling operation of the tensioning assembly and the sealing assembly. The control system is configured to operate the strapping tool in an automatic mode in which the tensioning assembly and the sealing assembly are sequentially actuated by, for example, a single action of the control system by an operator, and in a manual mode in which the tensioning assembly and the sealing assembly are sequentially actuated by multiple actions of the control system by the operator. 
         [0009]    In an embodiment, the sealing assembly includes a die and punch cooperating with one another to cut keys in the overlapping sections of strap. The tensioner motor is operated in a reverse direction following a sealing cycle to interlock the keys cut in the overlapping sections of strap. The control system, in the automatic mode, is configured to operate in the reverse direction following the sealing assembly actuation by action of the control system to interlock the keys. In an embodiment the action can be carried out by a single action of the control system. 
         [0010]    In an embodiment, the tensioner motor assembly is pivotally mounted to the body and is biased to move the tension wheel toward the foot. 
         [0011]    In an embodiment, a cam shaft is operably connected to the die and includes a position switch for sensing a position of the cam shaft. The position switch is operably connected to the control system. An embodiment of the tool includes a dynamic brake to stop rotation of the sealer motor assembly at an end of the sealing cycle. The dynamic brake can be controlled by the control system. 
         [0012]    The tool includes an actuation switch for controlling the tool. The actuation switch is operably connected to the control system which is operably connected to the tensioner motor assembly and the sealer motor assembly. The control system can include a strap tension adjusting device for varying a tension in the overlapping sections of steel strap. The control system can be configure to stop movement of the tensioning wheel based upon a setting of the strap tension adjusting device. 
         [0013]    A control system controls a strapping tool of the type for tensioning and forming a sealless joint in overlapping sections of steel strap around a load. The control system includes control circuitry operably connected to the tensioner motor assembly and the sealer motor assembly. In an embodiment, a position switch is operably connected to the sealer to determine a position of the seal. The control system includes an actuation switch. The control system is configured to operate the strapping tool in an automatic mode in which the tensioner motor assembly and the sealer motor assembly are sequentially actuated by a single action of the actuation switch. In an embodiment, the control system is operably connected to a dynamic brake to stop movement of the sealer motor assembly when the sealer reaches a predetermined position. 
         [0014]    In an embodiment, following a sealing cycle, the control system actuates the tensioner motor assembly in a reverse direction to secure the sealless joint. 
         [0015]    In a manual mode the tensioner motor assembly and the sealer motor assembly are sequentially actuated by multiple actions of the actuation switch. 
         [0016]    Other objects, features, and advantages of the disclosure will be apparent from the following description, taken in conjunction with the accompanying sheets of drawings, wherein like numerals refer to like parts, elements, components, steps, and processes. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0017]      FIG. 1  is perspective view of an embodiment of an electrically powered combination strapping tool; 
           [0018]      FIG. 2  is another perspective view of the tool; 
           [0019]      FIG. 3  a rear perspective view of the tool; 
           [0020]      FIG. 4  is a perspective view similar to  FIG. 2  showing portions of the housing removed for clarity of illustration; 
           [0021]      FIG. 5  is an enlarged perspective view of the tool illustrating various components and features of the tool; 
           [0022]      FIG. 6  is a rear perspective view similar to  FIG. 3  showing portions of the housing removed for clarity of illustration; 
           [0023]      FIG. 7  is an illustration of the interlocking key arrangement formed in the overlapping courses of strap; 
           [0024]      FIG. 8  is an illustration showing portions of the sealing and tensioning sections of the tool; 
           [0025]      FIG. 9  illustrates the positioning of the strap around a load; and 
           [0026]      FIG. 10  is an example of a control and operating scheme for the tool. 
       
    
    
     DETAILED DESCRIPTION 
       [0027]    While the present disclosure is susceptible of embodiment in various forms, there is shown in the drawings and will hereinafter be described one or more embodiments with the understanding that the present disclosure is to be considered illustrative only and is not intended to limit the disclosure to any specific embodiment described or illustrated. 
         [0028]    Referring now to the figures, an embodiment of the electrically powered combination strapping tool  10  is shown. The tool  10  is configured to tension steel strap S or strapping material around an object or load L, seal overlapping portions of the strap S to itself at a seal or joint J to form a tensioned loop around the load L and to cut the tensioned loop from the strap supply P. Generally, the strap S includes a feed or supply end P and a free end F that is fed around the load L and reinserted into the tool  10  to overlap the supply end P. 
         [0029]    For purposes of the present disclosure, the term “sealless” refers to the configuration or type of seal or joint that is made in the overlapping portions of the strap. Although a “seal” is made in the strap courses, the sealless joint is made by cutting or punching interlocking keys K or sections of the courses, as illustrated in  FIG. 7 . The term sealless is intended to define this type of joint or seal J as compared to a joint that is made using a separate element such as a crimp seal that is applied over and crimped onto the overlapping strap courses. 
         [0030]    The tool  10  includes a body  12 , a tensioning section  14  and a sealing section  16 . The tensioning section  14  includes a housing  18  and a first or tensioner motor assembly  20  operably mounted to the body  12 . The sealing section  16  includes a sealer  21 , housing  22  and a second or sealer motor assembly  24  operably mounted to the body  12 . The body  12  includes a foot  26 , a housing  28  and one or more handles  30  and  32  to facilitate handling and using the tool  10 . One handle can be a tool opening handle  30  above the tensioner motor assembly  20  and the other an operating handle  32  mounted above the body  12 . A receiver  34  is formed as part of or mounted to the body  12  for receiving a battery  36  or other power source. A temporary hold-down finger  38  can be positioned on the foot  12 , opposite the tensioner motor assembly  20 . The hold-down finger can be biased toward the foot  26 . 
         [0031]    The tensioning section  14  includes the tensioner motor assembly  20 , which has a motor  40 , such as a DC motor, and a gear housing  42  including a gear set  44  to convert the motor  40  output drive to a usable speed. The gear  44  set can include a planetary gear set (not shown) to reduce the output speed and to increase the output power or torque from the motor  40 . The gear set  44  includes a final drive (not shown) that meshes with a gear (not shown) on a tension wheel  46 . The tension wheel  46  is mounted normal to the final drive. The gear set  44  and final drive are housed in the gear housing  18  mounted to the tool body  12 . A gripping pad  48  can be positioned in the foot  26 , opposite the tension wheel  46 . 
         [0032]    The tensioner motor assembly  20 , gear housing  42  and tension wheel  46  are movably mounted to the body  12  to move the tension wheel  46  toward and away from the foot  26 . This permits the tool  10  to be opened to position the strap S between the foot  26  and the tension wheel  46 . In an embodiment, the tensioner motor assembly  20 , gear housing  42  and tension wheel  46  are pivotably mounted to the body  12  to pivot the tension wheel  46  toward and away from the foot  26 . The tensioner motor assembly  20 , gear housing  42  and tension wheel  46  can be biasedly mounted to the body  12 , such as by a spring (not shown), to bias the tension wheel  46  toward the foot  26  and into contact with the strap S in the closed position. 
         [0033]    The sealing section  16  includes the sealer motor assembly  24  which has a motor  50 , such as a DC motor and a drive  52 . In an embodiment, the drive  52  is a gear set  54  that includes a planetary gear set (not shown) that drives a cam shaft  56  through a final drive gear (not shown). The planetary gear set reduces the output speed and increases the output power or torque from the motor  50 . Other drives can be used to transfer power from the motor  50  to the cam shaft  56 , such as belts, chains or the like. 
         [0034]    Cams  58  on the cam shaft  56  contact and moves a set of dies  60  in the sealing section  16 . The dies  60  reciprocate toward and away from a punch  62  located on the foot  26  to bring the dies  60  into and out of contact with the overlapping course of strap S positioned between the dies  60  and the punch  62 . When the dies  60  engage the strap S (in a sealing portion of the cycle), the dies  60  and punch  62  form keys K in the strap S that, when shifted longitudinally, lock into one another. An example of a sealer section  16  is illustrated in  FIG. 8  and an example of an interlocking key K seal or joint J is illustrated in  FIG. 7 . The sealing section  16  also includes a cutter  64  to cut the looped and sealed strap S from the strap supply P during the sealing cycle. Similar to the dies  60 , the cutter  64  is driven by the rotation of the cam shaft  56 . 
         [0035]    The tool  10  is configured to permit operation in fully automatic and manual modes. To this end, the tool  10  includes a control system, shown generally at  66 , to control operation of the tool  10 . In an embodiment the tool  10  includes an actuation  68  switch and one or more circuits  70 ,  72  to control the tensioner motor  40  and the sealing motor  50 . In an embodiment, the tensioner motor and sealing motor circuits  70 ,  72  are provided on separate boards within the tool  10 . It will be appreciated that the tensioner and sealer motor boards  70 ,  72  can be combined on a single board. 
         [0036]    The control system  66  can further include a cam position switch or sensor  74  to sense the position of the cam shaft  56  in the sealing section  16 , a strap size/tension adjustment device  76 , an anti jam device  78  and a dynamic brake  80 . The cam position switch  74  is positioned to determine the position of the cam shaft  56  and thus the position of the cam lobes  58  (or cams), and consequently the dies  60  and cutter  64 . The strap size/tension adjustment device  76  can be, for example, a knob-type dial adjustment provided on the tool body  12 . Control of the anti jam device  78  can be incorporated within the tension/strap size adjustment dial  76 . The dynamic brake  80  is associated with the sealing motor  50  to brake or stop the motor  50  when the cam shaft  56  is at a home position and to bleed power from the motor  50  at the completion of the sealing cycle. The tool  10  can further include one or more indicators, such as LEDs, to provide indication of certain functions and states of the tool. An LED indicator  82  can be positioned within or around the actuation switch  68 . 
         [0037]    Referring to  FIG. 10 , in an operating scenario, the tool  10  is in a home position in which the spring biases the tension wheel  46  into contact with the foot  26 . When the battery is installed, as at step  102 , the tool  10  turns on and runs a self-test, as at step  104 . An indicator, such as the LED  84  in the actuation switch  68 , can be configured to flash in a predetermined sequence to indicate the operating state of the tool  10 . For example, the LED  84  can flash once to indicate that the tool  10  is in an automatic operating mode and twice to indicate that the tool  10  is in a manual operating mode. Once the tool  10  completes the self-test it is in a ready/sleep state as at step  106 . In the ready/sleep state, the tensioner and sealer motors  40  and  50  are off (no power to the motors), and the tool  10  is ready for operation in an automatic mode or a manual mode. 
         [0038]    To commence a strapping cycle, the tool  10  is opened by urging or pulling the tensioner motor assembly  20  toward the tensioner handle  30  to open a gap between the tension wheel  46  and the foot  26 . A lead or free end F of the strap S is positioned around the load and a supply end P of the strap S (from a strap dispenser) is positioned overlapping the free end F. The overlapping courses of strap S are positioned in the tool  10  between the tension wheel  46  and the foot  26  and between the dies  60  and punch  62  with the supply end P entering from the rear end (the tension wheel  46  end) of the tool  10  as illustrated in  FIGS. 8 and 9 , with the strap S courses positioned under the hold-down finger  38 . 
         [0039]    In one scenario of an automatic mode, depressing and releasing the actuation switch  68  commences the operating cycle. With overlapping strap S courses positioned between the tension wheel  46  and the foot  26  and between the dies  60  and punch  62 , the tension cycle starts, as at step  108 , in which the tensioner motor  40  operates to drive the tension wheel  46  to draw tension in the strap S. As the tensioner motor  40  operates, the actuation switch LED  84  is illuminated. When a predetermined amount of tension is drawn (as set by using the strap size/tension adjustment knob  76 ), the tensioner motor  40  stops and the LED indicator  84  goes out. 
         [0040]    The sealing cycle then starts, as at step  110 , in which the sealing motor  50  operates to rotate the cam shaft  56  and the cams  58  move into contact with and move the dies  60  downward to contact the strap S. When the sealing motor  50  starts, the actuation switch LED  84  illuminates to indicate tool  10  operation. The interlocking keys K are cut by the force of the cams  58  on the dies  60  forcing the dies  60  into the strap S and forcing the strap S against the punch  62 . The strap supply P end is cut to separate the looped strap S from the strap supply P. 
         [0041]    The sealing motor  50  continues to operate, and when the cam shaft  56  completes one full (360 degree) revolution, the cam switch or sensor  74  is triggered and the sealing motor  50  turns off. The dynamic brake  80  stops the cam shaft  56  at the home position by absorbing excess energy from the sealing motor  50 . The hold-down finger  38  at the foot  26  holds the strap S temporarily in place in the tool  10 . Once sealing is complete, the tensioner motor  40  operates in reverse for a short period (less than about 1 second) to allow the tension in the strap S to “pull” the keys K into an interlocking arrangement (see,  FIG. 7 ), which forms the seal or joint J. 
         [0042]    Once the sealing cycle is completed, as at step  112 , with the dies  60  returned to the home position and the sealing motor  50  stopped, the LED indicator  84  goes out. The tool  10  is then in the ready/sleep state. 
         [0043]    In automatic mode, depressing and releasing the actuation switch  68  at any time during the tension and/or sealing cycles (see, steps  108  and  110 ), can, for example, stop the tool  10 , and depressing and holding the actuation switch  68 , as at step  114 , can operate the tensioner motor  40  in reverse. This functions as an emergency stop of the tool  10 . 
         [0044]    The tool  10  can also be operated in manual mode in which, for example, a first depression of the actuation switch  68  commences the tension cycle, and the tensioner motor  40  stops when a predetermined tension is reached. In this example of manual operation, a second depression of the actuation switch  68  may then be required to commence the sealing cycle. The auto-stop functions (for example, depressing and/or depressing and holding the actuation switch) can again serve to stop the tool  10  and/or reverse the tensioner motor  10  in manual mode. 
         [0045]    With reference to the trigger functions and events referenced in  FIG. 10 , Trigger Function (1) (•) when in Ready mode  106 , will begin the tensioning cycle; Trigger Function (2) (-) when in Ready mode  106 , will cause the tool to reverse until the trigger is released; and Trigger Function (3) (•) at any time during the tension cycle will stop the motor, where (•) indicates that the trigger is held for less than a specified period of time and (-) indicates that the trigger is held for more than a specified period of time. 
         [0046]    (*) Automatic mode—after tensioning tool automatically seals. Manual mode—after tensioning tool waits for a second trigger event to activate sealer motor. (**) Tension knob—selects strap width, mode and option to only activate sealer motor. 
         [0047]    As noted above, the tool  10  can include an anti jam feature  78  actuation of which can be incorporated into the strap size/tension adjusting device  76 . When the anti- 78  jam function is selected and the actuation switch  68  is depressed, the tensioner motor  40  operates in reverse to clear any material that may be jammed in the tool  10 , between the tension wheel  46  and the foot  26 . The sealing motor  50  will cycle once, also to clear any material that may be jammed in the tool  10 . 
         [0048]    The tool  10  as disclosed and described is an electrically powered tool that uses a battery  36 ; it will however be appreciated that the tool  10  can be configured to operate with a voltage converter (not shown) for example, for use at line voltages (e.g., 120V-240V). In addition, although the tool  10  is described as including a tensioner motor  40  and a sealing motor  50 , it is contemplated that a single motor can be used to carry out both the tension and sealing functions with appropriate drives in place. 
         [0049]    It will also be appreciated by those skilled in the art that various other automatic and manual operating scenarios are and can be contemplated in connection with the disclosed electrically powered combination hand-held strapping tool  10 , and that such other operating scenarios are within the scope and spirit of the present disclosure. 
         [0050]    It should be understood that various changes and modifications to the presently preferred embodiments disclosed herein will be apparent to those skilled in the art. Such changes and modifications can be made without departing from the spirit and scope of the present disclosure and without diminishing its intended advantages. It is therefore intended that such changes and modifications be covered by the appended claims.