TM 10-3930-664-10 1-22. MAST ASSEMBLY FORKS.  Constructed of forged steel and mounted on the rotate carriage.  Separation between fork arms is adjusted to accommodate loads of varying width.  Positioning notches on the rotate carriage and indexing lugs on the fork arms are used to adjust the distance between fork arms and lock the fork arms in place. ROTATE CARRIAGE.  Steel frame Is attached to the sideshift carrier.  Provides vertical support for the rear of the load positioned on the forks and rotates the forks.  Body of rotation cylinder is attached to the sideshift carrier and the cylinder rod  end  is  attached  to  the  rotate  carriage.    Controlled  by  the  rear  joystick  on  the  directional  control  valve.    Moving  the joystick  to  the  left  causes  the  cylinder  to  extend  and  rotate  the  forks  counterclockwise.    Moving  the  joystick  to  the  right causes the cylinder to retract and rotate the forks clockwise. LOAD BACKREST.  Steel frame attached to the rotate carriage.  Provides support and stability for the load positioned on the forks.  Load backrest can be removed for operating inside containers. SIDESHIFT CARRIER.  Steel frame supports the rotate carriage and forks.  Hydraulic sideshift cylinder drives two chains which  sideshift  the  rotate  carriage  assembly.    Controlled  by  the  front  joystick  on  the  directional  control  valve.    Moving joystick to the left causes the cylinder to retract and moves the forks to the left.  Moving joystick to the right causes the cylinder to extend and moves the forks to the right. MAST.    Composed  of  three  sections;  inner  rail,  intermediate  rail,  and  outer  rail  assemblies.    Raises  and  lowers  the sideshift carrier along with the rotate carriage and forks.  Rollers mounted on the sideshift carrier move in channels formed by the inside of the I-beams used for the sides of the inner rail assembly.  A chain, driven by the freelift cylinder, provides the up and down movement of the sideshift carrier.  Forks can be raised from ground level to 48 inches (122 cm) above the ground by lifting the sideshift carrier.  Rollers mounted on the inner rail move in channels formed by the inside of the I- beams  used  for  the  sides  of  the  intermediate  rail  assembly  while  rollers  mounted  to  the  intermediate  rail  move  in  the channels  which  form  the  sides  of  the  outer  rail  assembly.    When  the  rod  of  the  freelift  cylinder  reaches  its  maximum extension, the two mainlift cylinders begin to operate.  The mainlift cylinder rods are attached to the top of the intermediate rail and lift both the intermediate rail and the inner rail as the rods extend.  At the same time, the inner rail is lifted by two chains driven by the same two mainlift cylinders so that the inner rail along with the sideshift carrier and forks is moved upward out of the intermediate rail assembly.  Through the combined movements of the sideshift carrier, intermediate rail, and inner rail the forks can be raised to a height of 120 inches (305 cm) above ground level.  Up and down movement of the  mast  is  controlled  by  the  front  joystick  on  the  directional  control  valve.    Pushing  the  joystick  forward  retracts  the cylinders and lowers the forks.  Pulling the joystick back extends the cylinders and raises the forks. 1-14