Concrete trowel

Abstract

A concrete trowel including: a frame including a blade guard extending therefrom; a drive assembly including a motor mounted on the frame and a drive hub configured to receive torque from the motor; a rotor rotatable about a rotational axis within the blade guard and including a plurality of blades and an attachment portion for selectively engaging the drive hub; and a quick-change coupling for selectively attaching the rotor and the drive hub for co-rotation therewith, wherein the quick-change coupling includes: a pull-through clamp configured to fit through the attachment portion of the rotor and imparts a clamping force on the attachment portion along the rotational axis of the rotor to clamp the rotor to the drive hub along the rotational axis, wherein the pull-through clamp includes a spring that remains on the drive hub when the attachment portion of the rotor is removed from the quick-change coupling.

What is claimed is: 
     
         1 . A concrete trowel comprising:
 a frame including a blade guard extending therefrom;   a drive assembly including a motor mounted on the frame and a drive hub configured to receive torque from the motor;   a rotor rotatable about a rotational axis within the blade guard and including a plurality of blades and an attachment portion for selectively engaging the drive hub; and   a quick-change coupling for selectively attaching the rotor and the drive hub for co-rotation therewith, wherein the quick-change coupling comprises:
 a pull-through clamp configured to fit through the attachment portion of the rotor and imparts a clamping force on the attachment portion along the rotational axis of the rotor to clamp the rotor to the drive hub along the rotational axis, wherein the pull-through clamp includes a spring that remains on the drive hub when the attachment portion of the rotor is removed from the quick-change coupling. 
   
     
     
         2 . The concrete trowel of  claim 1 , wherein the pull-through clamp imparts a clamping force between the attachment portion and the drive hub along the rotational axis of the rotor. 
     
     
         3 . The concrete trowel of  claim 1 , wherein the pull-through clamp is driven by an over center cam. 
     
     
         4 . The concrete trowel of  claim 1 , wherein the pull-through clamp includes a pull plate and a linkage extending from the pull plate and through an aperture in the attachment portion. 
     
     
         5 . The concrete trowel of  claim 4 , wherein the attachment portion is positioned between the pull plate and the drive hub. 
     
     
         6 . The concrete trowel of  claim 5 , wherein the spring is configured to impart a spring force onto the pull plate to pull the attachment portion onto the drive hub. 
     
     
         7 . The concrete trowel of  claim 5 , wherein the pull plate has a first interface that engages a complementary interface of the attachment portion. 
     
     
         8 . A concrete trowel comprising:
 a frame including a blade guard extending therefrom;   a drive assembly including a motor mounted on the frame and a drive hub configured to receive torque from the motor;   a rotor rotatable about a rotational axis within the blade guard and including a plurality of blades and an attachment portion for selectively engaging the drive hub; and   a quick-change coupling for selectively attaching the rotor and the drive hub for co-rotation therewith, wherein the quick-change coupling comprises:
 a pull-through clamp configured to fit through the attachment portion of the rotor, the pull-through clamp movable between a first position in which the pull-through clamp imparts a clamping force on the attachment portion along the rotational axis of the rotor to clamp the rotor to the drive hub along the rotational axis and a second position in which the clamping force on the attachment portion is released to allow the rotor to be removed from the quick-change coupling. 
   
     
     
         9 . The concrete trowel of  claim 8 , wherein the pull-through clamp includes a spring that remains on the drive hub when the pull-through clamp is in the second position. 
     
     
         10 . The concrete trowel of  claim 8 , wherein the pull-through clamp imparts a clamping force between the attachment portion and the drive hub along the rotational axis of the rotor. 
     
     
         11 . The concrete trowel of  claim 8 , wherein the pull-through clamp is driven by an over center cam. 
     
     
         12 . The concrete trowel of  claim 8 , wherein the pull-through clamp includes a pull plate, a linkage extending from the pull plate and through an aperture in the attachment portion, and a spring that remains on the drive hub when the pull-through clamp in the second position. 
     
     
         13 . The concrete trowel of  claim 12 , wherein the attachment portion is positioned between the pull plate and the drive hub. 
     
     
         14 . The concrete trowel of  claim 13 , wherein when the pull-through clamp is in the first position, the spring is configured to impart a spring force onto the pull plate to pull the attachment portion onto the drive hub. 
     
     
         15 . The concrete trowel of  claim 13 , wherein the pull plate has a first interface that engages a complementary interface of the attachment portion. 
     
     
         16 . A concrete trowel comprising:
 a frame including a blade guard extending therefrom;   a drive assembly including a motor mounted on the frame and a drive hub configured to receive torque from the motor;   a rotor rotatable about a rotational axis within the blade guard and including a plurality of blades; and   a quick-change coupling for selectively attaching the rotor and the drive hub for co-rotation therewith, wherein the quick-change coupling comprises:
 a pull-through clamp configured to fit through an attachment portion that removably couples the rotor to the drive hub and imparts a clamping force on the attachment portion along the rotational axis of the rotor to clamp the rotor to the drive hub along the rotational axis, wherein the pull-through clamp includes a spring that remains on the drive hub when the rotor is removed from the quick-change coupling. 
   
     
     
         17 . The concrete trowel of  claim 16 , wherein the pull-through clamp is movable between a first position in which the pull-through clamp imparts the clamping force on the attachment portion along the rotational axis of the rotor to clamp the rotor to the drive hub along the rotational axis and a second position in which the clamping force on the attachment portion is released to allow the rotor to be removed from the quick-change coupling. 
     
     
         18 . The concrete trowel of  claim 16 , wherein the pull-through clamp is driven by an over center cam. 
     
     
         19 . The concrete trowel of  claim 16 , wherein the pull-through clamp includes a pull plate and a linkage extending from the pull plate and through an aperture in the attachment portion. 
     
     
         20 . The concrete trowel of  claim 19 , wherein the attachment portion is positioned between the pull plate and the drive hub, and wherein the spring is configured to impart a spring force onto the pull plate to pull the attachment portion onto the drive hub.