MPI 40 Series - Electro-Mechanical Assemblies; Head Load Solenoid; Head;Carriage Assembly; Stepper Motor;Band Assembly

3.3 ELECTRO-MECHANICAL ASSEMBLIES
3.3.1 Head Load Solenoid
The soleniod, when energized, will allow the spring tensioned load
arm of the carriage to lower its felt pad (in Model 41) or upper
head (in Model 42) and press on the diskette opposite the lower
head. The load arm is lifted when the door is opened even if the
solenoid is energized.
3.3.2 Head/Carriage Assembly
The carriage assembly consists of a fixed lower read/write head and
a spring tensioned load arm with either a felt pad (in Model 41) or
a second read/write head (in Model 42) on its end. When loaded by
the head load solenoid it will apply about 20 grams of pressure on
the diskette opposite the lower head. The carriage assembly slides
on highly polished guide rods when moved by the stepper motor/band
assembly.
3.3.3 Stepper Motor/Band Assembly
The read/write head(s) are accurately positioned by a stepper motor
and metal band mechanism. The stepper motor is a 100 pole 4 phase
motor which, when not in a stand-by mode, always has two adjacent
phases energized. Each stepping pulse de-energizes one phase
and energizes another, thus rotating the stepper motor by 3.6°.
This rotary motion is translated by the pulley on the shaft of the
stepper motor and the flexible stainless steel band which encircles
it into the proper amount of linear motion necessary to reposition
the read/write heads by precisely one track.
3.3.4 Spindle And Motor
The spindle motor is mounted at the rear of the drive and transfers
its rotary motion to the spindle pulley by a drive belt. This
causes the diskette to be rotated at 360 RPM. It is held against
the hub by the diskette clamp, which contains a registration cone.
This cone, located opposite the spindle fac~, serves to center the
diskette on the spindle hub.
3.3.5 Door Lock Mechanism
The user can lock and unlock the drive door by controlling the
solenoid within the door lock mechanism. When energized, it causes
the mechanism's actuator to interfere with normal door opening
movement. When de-energized, movement is unrestricted; the door is
unlocked. In its standard configuration, the door is locked
whenever the drive is selected.
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