Pump transmission carriage assembly

A metering pump includes a motor having a motor shaft extending through a drive housing, a carriage assembly disposed around the motor shaft and within the drive housing, a plunger return block mounted to the carriage assembly, a piston disposed along an axis, and a carriage bearing disposed on the motor shaft and within the carriage assembly, slidably coupled to the carriage assembly, and configured to provide a second contact point for maintaining the alignment of the carriage assembly with the axis of the piston. The piston further includes a stroke adjuster mounted to the carriage assembly to provide a first contact point for maintaining the alignment of the carriage assembly with the piston, a drive shaft connected to the stroke adjuster, and a plunger connected to the drive shaft. The metering pump also includes a cam coupled to the motor shaft to rotate with the motor shaft and a bearing disposed around the cam to rotate therewith and to contact the stroke adjuster and the plunger return block.