NOTES ON ELL ARM MOVEMENT
Components:
The ELL arm assembly is consisted of two parts:
Upper part: visible with in the ELL.
Lower part—lower bearing housing.
Forearm
Elbow Spindle
Cable
Shoulder Pulley
Upper Arm
Upper Bearing Housing
Shaft
Rotation Motor
Tube
Extension Motor
Bearings
Lower Bearing Housing
1
Movement of upper part:
Rotation: Forearm (fork) locked to the upper arm. Upper arm and forearm rotate together
against the etcher.
Extension: Upper arm (arm housing) rotates around the shoulder relative to the etcher in one
direction. Forearm rotates around the elbow relative to the upper arm in the opposite direction
with double the speed as the upper arm rotation.
Description of motion during Rotation:
Object
Motion type
Direction (up/down,
Extent of motion
(translational
towards indexer,
(how much does it
motion/rotational
away from indexer,
move from
motion, etc)
CW, CCW, etc.)
beginning to end)
Upper arm against
shoulder
Fore arm against
elbow
Shaft against etcher
Rotation
CCW
90°
No motion. Thus locked NA
in to upper arm
Rotation
CCW
NA
Tube against etcher Rotation
90°
CCW
90°
Direction (up/down,
towards indexer,
away from indexer,
CW, CCW, etc.)
Extent of motion
(how much does it
move from
beginning to end)
Upper arm against Rotation
shoulder
Fore arm against
Rotation
elbow
Shaft against etcher No motion
CCW
90°
CW
180°
NA
NA
Tube against etcher Rotation
CCW
90°
Description of motion during extension:
Object
Motion type
(translational
motion/rotational
motion, etc)
Cause of extension: arm housing (upper arm) rotation against etcher, shoulder pulley fixed
against etcher. This relative motion of arm housing against shoulder pulley causes the belt
around the pulley to wrap around or open up. Points on the belt move away from the shoulder
on the side of the belt that opens up and gets closer to the shoulder on the side of the belt that
wraps around. This relative motion of the belt against the shoulder from the perspective of a
person standing on the shoulder drags and rotates the elbow pulley at the other end of the belt.
This in turn causes the folk (fore arm) to rotate. The combined motion of upper arm rotation
and that of the forearm form a extension motion of the ELL arm.
Cause of rotation: arm housing (upper arm) and the shoulder pulley both move relative to the
etcher at the same pace. No relative motion of the arm housing against the shoulder pulley. No
2
motion of the belt against the arm housing. No rotation of the elbow. Forearm/fork locked to
the upper arm. They rotate together against the etcher.
Position Sensing:
There are two rotation positions of the ELL arm: 0 degree position--Ready to rotate to chamber
position and 90 degree position--Ready to rotate to load-point position. (see figure below).
There are three extension positions: Arm not extended (folded) position. Arm extended to the
chamber (CW extension) and arm extended to the load-point position (CCW extension).
Ext and Rot sensors and flag wheels:
Ready to extend to
chamber position
Ready to extend
to ldpt position
Viewed
from top
Viewed Rot
from top to
chmb
P6 and P7 9P7
are Rot
sensors
9P5
ldpt
Rotation sensors
Ext
sensors
From this extension position, the
flag disc rotates CCW 90° to reach
the not extended position (in ELL)
and another CCW90° to reach the extended to ldpt position.
Non-interruption = T in screen display
Interruption = F in screen display
3
9P9 Shown as the extended
home to reactor position
Rot
9P6 to
ldpt
9P8
chmb
Rot and Ext sensors mounted on lower bearing housing (boat). Rot flag wheel mounted on
etcher. Ext flag wheel mounted on the tube. They are not on the same plane.
Relative orientation of the sensors to the chamber:
When the ELL arm is at the rotated to the chamber position, the sensor positions are shown as
below:
Looking top down from the etcher
Ldpt
direction
9P9
home Shown as the rot to
chamber position
9P7
9P6
Chamber
direction
9P5
ldpt
9P8
chmb
Ext
sensors
Non-interrupted = T, interrupted = F.
Notice when the arm is extended into the chamber or to the ldpt, 9p5=T, 9P9=F, 9P8=T. Thus
the etcher does not depend on the combination of sensor states to sense its position. Instead, it
depends on some sort of sequential logic to do so, such as perhaps the transition from F to T to
mark the position.
Sensor Position
Arm retracted
Arm extended to ldpt
Connector type
9P9
9P5
Software Index
60
71
Arm extended to chamber
9P8
72
Arm rotated to ldpt
9P6
73
Arm rotated to chamber
9P7
74
4