Strapping apparatus

Abstract

In order, in the case of a strapping apparatus for strapping articles with a strapping band, having a base plate which is provided for arranging on an article, having a tensioning device with which a band tension can be applied to the strapping band, the tensioning device being provided for this purpose with an actuable tensioning tool which can be brought into and out of contact with the band, having a sealing device with which, by contact with the band, two band layers can be permanently connected to each other by forming a seal between the two band layers, being provided with a clamping device which has at least one clamp with two interacting clamping elements for clamping the band between the clamping elements, and being provided with at least one actuating element with which a magnitude of a tensioning force which can be applied to the strapping band or a magnitude which is dependent on the tensioning force can be set, to improve the strength of friction-welded band strapping seals produced by the strapping apparatus, it is proposed that a cooling time period for the seal, during which the strapping apparatus does not release the strapping band after the end of a welding time, is variable depending on the variably adjustable tensioning force or a magnitude which is dependent thereon.

What I claim is: 
     
         1 . A strapping tool for strapping an article with a plastic strapping band, the strapping tool comprising:
 a housing defining a battery receptacle;   a tensioning wheel at least partially disposed within the housing;   a tensioning counter holder comprising a tensioning-counter-holder surface;   a welding-counter-holder comprising a welding-counter-holder surface;   a welding shoe movable relative to the welding-counter-holder surface between a rest position and a welding position;   a battery removably receivable in the battery receptacle of the housing;   an input device actuatable to set a tensioning force; and   a controller powered by the battery and configured to:
 (1) actuate the tensioning wheel to, when the strapping band is positioned between the tensioning wheel and the tensioning-counter-holder surface, tension the strapping band to the tensioning force; 
 (2) actuate the welding shoe to move to the welding position to clamp two overlying layers of the strapping band against the welding-counter-holder surface and to oscillate for a welding time to seal the two overlying layers of the strapping band to one another; and 
 (3) after a cooling time has elapsed following the welding time, actuate the welding shoe to release the strapping band, wherein the cooling time is a first cooling time when the tensioning force is a first tensioning force and the cooling time is a second cooling time greater than the first cooling time when the tensioning force is a second tensioning force greater than the first tensioning force. 
   
     
     
         2 . The strapping tool of  claim 1 , wherein the controller is further configured to determine the cooling time based on the tensioning force. 
     
     
         3 . The strapping tool of  claim 2 , wherein the controller is further configured to determine the cooling time based on the tensioning force and the welding time. 
     
     
         4 . The strapping tool of  claim 3 , wherein .  the input device is actuatable to set the welding time. 
     
     
         5 . The strapping tool of  claim 4 , wherein the controller stores data representing multiple preset tensioning forces and data representing multiple preset welding times, wherein the tensioning force is one of the preset tensioning forces and the welding time is one of the preset welding times, wherein the controller stores data representing a cooling time factor associated with each of the preset tensioning forces and each of the preset welding times, wherein at least two of the cooling time factors are different, wherein the controller is configured to determine the cooling time based on the cooling time factors associated with the tensioning force and the welding time. 
     
     
         6 . The strapping tool of  claim 5 , wherein the controller is configured to determine the cooling time by multiplying the cooling time factors associated with the tensioning force and the welding time. 
     
     
         7 . The strapping tool of  claim 4 , wherein the input device comprises a first input device actuatable to set the tensioning force and a second input device actuatable to set the welding time. 
     
     
         8 . The strapping tool of  claim 1 , wherein the controller is further configured to actuate the welding shoe to move the welding shoe from the welding position back to the rest position to release the strapping band. 
     
     
         9 . The strapping tool of  claim 1 , further comprising one or more motors powered by the battery and operably coupled to the tensioning wheel to drive the tensioning wheel and to the welding shoe to move the welding shoe from the rest position to the welding position and to oscillate the welding shoe, wherein the controller is configured to actuate the tensioning wheel by controlling the motor to drive the tensioning wheel, wherein the controller is configured to actuate the welding shoe to move to the welding position and to oscillate the welding show by controlling the motor to move the welding shoe to the welding position and to oscillate the welding shoe. 
     
     
         10 . The strapping tool of  claim 9 , wherein the one or more motors comprises a single motor. 
     
     
         11 . The strapping tool of  claim 1 , further comprising a rocker comprising the tensioning counter holder, the rocker pivotable about a rocker pivot axis from a rest position to an open position to increase a distance between the tensioning wheel and the tensioning-counter-holder surface. 
     
     
         12 . The strapping tool of  claim 11 , further comprising a rocker lever pivotable between a rest position and an open position, wherein the rocker lever is operably connected to the rocker such that pivoting of the rocker lever from the rest position to the open position causes the rocker to pivot from the rest position to the open position and pivoting of the rocker lever from the open position to the rest position causes the rocker to pivot from the open position to the rest position. 
     
     
         13 . The strapping tool of  claim 12 , wherein the tensioning-counter-holder surface contacts the tensioning wheel when the rocker is in the rest position. 
     
     
         14 . The strapping tool of  claim 1 , further comprising an actuating element operable to initiate a strapping operation, wherein responsive to an actuation of the actuating element, the controller is configured to automatically conduct (1)-(3). 
     
     
         15 . A method of operating a strapping tool, the method comprising:
 receiving an input associated with a tensioning force;   actuating a tensioning wheel to, when a strapping band is positioned between the tensioning wheel and a tensioning-counter-holder surface of a tensioning counter holder, tension the strapping band to the tensioning force;   actuating a welding shoe to move to a welding position to clamp two overlying layers of the strapping band against a welding-counter-holder surface of a welding counter holder and to oscillate for a welding time to seal the two overlying layers of the strapping band to one another; and   after a cooling time has elapsed following the welding time, actuating the welding shoe to release the strapping band, wherein the cooling time is a first cooling time when the tensioning force is a first tensioning force and the cooling time is a second cooling time greater than the first cooling time when the tensioning force is a second tensioning force greater than the first tensioning force.   
     
     
         16 . The method of  claim 15 , further comprising determining the cooling time based on the tensioning force. 
     
     
         17 . The method of  claim 16 , further comprising determining the cooling time based on the tensioning force and the welding time. 
     
     
         18 . The method of  claim 17 , further comprising receiving an input associated with the welding time. 
     
     
         19 . The method of  claim 15 , further comprising actuating the welding shoe to move the welding shoe from the welding position back to the rest position to release the strapping band. 
     
     
         20 . The method of  claim 15 , wherein actuating the tension wheel comprises controlling one or more motors to drive the tension wheel and actuating the welding shoe comprises controlling the one or more motors to actuate the welding shoe.