An electronically controlled journal loading system 20 for controlling and
adjusting the amplitude of the load applied to a journal assembly 19 of a
pulverizing mill 10. The journal loading system 20 includes a servomotor
44, resolver 134, vertical gearbox 42, coil spring assembly 40,
controller 46 and a user interface 48. The journal loading system 20
provides electronic control and adjustment of the force applied to the
journal assembly 19 to thereby increase or decrease the load that a
grinding roll 18 imposes on the material being pulverized. In the mode of
operation of the servo journal loading system 20, a desired load set
point is selected via the user/operator interface 48. The servomotor 44
rotates a preload stud (or servo screw) 50 within the coiled spring
assembly 40 in the appropriate direction via the gearbox 42. As the
preload stud 50 turns, a bronze nut 100 and bushing 94 move axially along
the stud to compress or decompress the spring 86. Based upon the linear
movement of the preload stud 50 and the precalculated spring force of the
spring 86, the load applied to the journal assembly 19 is displayed on
the operator interface 48. Once the journal loading level is achieved the
servomotor 44 can be turned off since the spring assembly 40 maintains
the selected loading to the journal assembly 19.