Strapping tool with drag torque lock

Abstract

Various embodiments of the present disclosure provide a strapping tool including a tensioning assembly, a scaling assembly, a motor, and a transmission assembly. The transmission assembly operably connects the motor to the tensioning assembly and the sealing assembly. The motor can (via the transmission assembly) alternately drive the tensioning assembly to tension a loop of strap around a load and the sealing assembly to seal the strap to itself. The strapping tool also includes a locking assembly that prevents the motor from driving the sealing assembly via drag torque generated by the transmission assembly while the motor is driving the tensioning assembly.

1 . A strapping device comprising:
 a tensioning assembly comprising tensioning-assembly gearing operably connected to a tension wheel to rotate the tension wheel;   a sealing assembly comprising sealing-assembly gearing;   a motor operably connected to a drive gear to drive the drive gear in a first rotational direction and a second rotational direction opposite the first rotational direction; and   a transmission assembly comprising:
 first gearing operably connecting the drive gear to the tensioning-assembly gearing such that rotation of the drive gear in the first rotational direction drives tensioning-assembly gearing to rotate the tension wheel in a tensioning rotational direction; and 
 second gearing operably connecting the drive gear to the sealing-assembly gearing such that rotation of the drive gear in the second rotational direction drives the sealing-assembly gearing; and 
   a locking assembly engaged to the second gearing to prevent the second gearing from driving the sealing-assembly gearing when the motor is driving the drive gear in the first rotational direction.   
     
     
         2 . The strapping device of  claim 1 , wherein the second gearing comprises a sealing-assembly drive shaft operably connected to the sealing-assembly gearing to drive the sealing-assembly gearing, wherein the locking assembly is operably connected to the sealing-assembly drive shaft to prevent the sealing-assembly drive shaft from driving the sealing-assembly gearing when the motor is driving the drive gear in the first rotational direction. 
     
     
         3 . The strapping device of  claim 2 , wherein the sealing-assembly drive shaft comprises a sealing-assembly drive gear drivingly engaged to a driven gear of the sealing-assembly gearing. 
     
     
         4 . The strapping device of  claim 2 , wherein the locking assembly comprises a locking-assembly freewheel mounted to the sealing-assembly drive shaft and enabling the sealing-assembly drive shaft to rotate in a sealing rotational direction opposite the tensioning rotational direction. 
     
     
         5 . The strapping device of  claim 4 , wherein the locking assembly further comprises a locking ring mounted to the locking-assembly freewheel, wherein the locking ring is mounted within and fixed in rotation relative to a support to prevent the sealing-assembly drive shaft from rotating in the tensioning rotational direction and driving the sealing-assembly gearing when the motor is driving the drive gear in the first rotational direction. 
     
     
         6 . The strapping device of  claim 5 , further comprising a locking-ring retainer engaging the locking ring and fixing the locking ring in rotation relative to the support. 
     
     
         7 . The strapping device of  claim 5 , wherein the locking-ring retainer is mounted to in the support. 
     
     
         8 . The strapping device of  claim 7 , wherein the locking-ring retainer is removable from the support. 
     
     
         9 . The strapping device of  claim 7 , wherein the support comprises a tensioning-assembly support to which the tensioning assembly is mounted. 
     
     
         10 . The strapping device of  claim 6 , wherein the locking ring defines multiple circumferentially spaced openings therethrough, wherein part of the locking-ring retainer projects into one of the openings to fix the locking ring in rotation relative to the support. 
     
     
         11 . The strapping device of  claim 10 , wherein the locking-ring retainer comprises a body, a nose captively received in a bore defined in the body, and a nose-biasing element biasing the nose to an open end of the bore such that part of the nose projects from the open end of the bore and into the one of the openings of the locking ring. 
     
     
         12 . The strapping device of  claim 11 , wherein the nose-biasing element has a stiffness sufficient to enable the sealing-assembly drive shaft and the locking ring to rotate relative to the locking-ring retainer in the tensioning rotational direction responsive to application of a torque in the tensioning rotational direction that exceeds a resistive force applied by the nose-biasing element. 
     
     
         13 . The strapping device of  claim 5 , wherein the tensioning assembly comprises a driven shaft operably connected to the tension wheel to drive the tension wheel,
 wherein the first gearing comprises a first freewheel mounted to the driven shaft and a first driven gear mounted to the freewheel,   wherein the drive gear is drivingly engaged to the first driven gear,   wherein the first driven gear is operably connected to the second gearing to drive the second gearing,   wherein the first freewheel is configured to transmit rotation of the first driven gear in the tensioning rotational direction to the driven shaft and to not transmit rotation of the first driven gear in the sealing rotational direction to the driven shaft.   
     
     
         14 . The strapping device of  claim 13 , wherein the second gearing further comprises a second freewheel mounted to the sealing-assembly drive shaft and a second driven gear mounted to the second freewheel,
 wherein the first driven gear is operably connected to the second driven gear to drive the second driven gear,   wherein the second freewheel is configured to transmit rotation of the second driven gear in the sealing rotational direction to the sealing-assembly drive shaft and to not transmit rotation of the second driven gear in the tensioning rotational direction to the sealing-assembly drive shaft.   
     
     
         15 . The strapping device of  claim 14 , further comprising a connector operably connecting the first driven gear to the second driven gear. 
     
     
         16 . The strapping device of  claim 15 , wherein the first gearing further comprises a second-gearing drive gear fixed in rotation with the first driven gear, wherein the connector operably connects the second-gearing drive gear to the second driven gear. 
     
     
         17 . The strapping device of  claim 15 , wherein the connector comprises a toothed belt. 
     
     
         18 . The strapping device of  claim 1 , wherein the transmission assembly further comprises the locking assembly.