Pallet truck assembly

Abstract

A powered pallet truck with a selectable effective reduced turning radius, and an intermediate roller assembly for mounting on the powered pallet truck, are provided. The intermediate roller assembly can include a base, a linear actuator pivotably connected at a base end to the base, a linkage pivotably connected to the base, and at least one roller having an axis pivotably connected to an actuating end of the linear actuator and to the linkage, the at least one roller thus being movable between a retracted and an engagement position. The assembly can be mounted to the underside of a pallet truck fork having a load wheel. A turning radius effectively defined by a drive wheel of the pallet truck and the intermediate roller, or a turning radius effectively defined by the drive wheel and the load wheel, can be selected.

1 . An intermediate roller assembly for mounting on an underside of a fork of a powered pallet truck, the powered pallet truck comprising at least one load wheel mounted on the fork and a hydraulic system including a first hydraulic actuator, the first hydraulic actuator being coupled to an axle of the at least one load wheel to move the at least one load wheel between a retracted position and an extended position, the intermediate roller assembly comprising:
 a base;   a second hydraulic actuator pivotably connected at a base end to the base;   a linkage pivotably connected to the base;   at least one roller having an axis pivotably connected to an actuating end of the second hydraulic actuator and to the linkage, the at least one roller thus being movable between a retracted and an engagement position; and   a diverter valve adapted for connection to the hydraulic system and the first and second hydraulic actuators to selectively place either the first or second hydraulic actuator in fluid communication with a hydraulic pressure source of the hydraulic system.   
     
     
         2 . The intermediate roller assembly of  claim 1 , wherein the base is adapted for fastening to the underside of the fork. 
     
     
         3 . The intermediate roller assembly of  claim 1  installed on the underside of the fork of the powered pallet truck and disposed between at least one drive wheel of the powered pallet truck and the at least one load wheel of the fork, such that when the at least one roller is in the engagement position and in contact with a work surface and the at least one load wheel is not in contact with the work surface, a turning radius of the powered pallet truck is determined by a distance between the at least one roller and the at least one drive wheel. 
     
     
         4 . An intermediate roller assembly for mounting on a powered pallet truck, the intermediate roller assembly comprising:
 a base adapted for mounting to the powered pallet truck;   a linear actuator pivotably connected at a base end to the base;   a linkage pivotably connected to the base; and   at least one roller having an axis pivotably connected to an actuating end of the linear actuator and to the linkage, the at least one roller being movable between a retracted and an engagement position by operation of the linear actuator.   
     
     
         5 . The intermediate roller assembly of  claim 4 , wherein the linear actuator comprises a hydraulic cylinder. 
     
     
         6 . The intermediate roller assembly of  claim 5 , further comprising a diverter valve adapted for connection to the hydraulic cylinder and a hydraulic system of the powered pallet truck. 
     
     
         7 . The intermediate roller assembly of  claim 6 , wherein the hydraulic system is operable to control at least one load wheel of the powered pallet truck, and wherein the diverter valve, when connected to the hydraulic system, permits the hydraulic system to control the hydraulic cylinder.