Burford 2200M, Manual

Page: 53 / 214

Operation 51
CHAPTER 4: OPERATION
Theory Of Operation
Before discussing the specifics
of
the Burford
®
Model
2200M/2300M Electronic Smart
Tyer, the overall operation of the
tyer will be described to illustrate
the principles of the tying cycle.
The Model 2200M/2300M is
designed to gather and securely
close the neck of a plastic bag by
twist tying it with a piece of
reinforced ribbon.
The plastic bag first encounters
a set of gathering brushes that
help to flatten and straighten the bag neck. The brushes gently pull the bag neck and
product against the inlet guide and main plate of the tyer. As the bag neck exits the
brushes it is directed towards the gathering belts of the tyer. The gathering belts, which
move at a selectable continuous rate of speed, transport the bag neck towards the tying
position. As it approaches the tying position, the bag neck actuates the bag switch, which
readies the electronics for the start of the tie cycle. When the bag neck releases the bag
switch, the Model 2200M/2300M controller waits for a short time before commencing the
tie cycle. This delay allows the bag neck to gather against the ribbon for a more secure
tie. Then the needle begins to move downward and allows the spring-loaded bag stop to
engage, thereby restraining the end of the bag neck. The needle continues to rotate and
wraps the ribbon around the neck of the bag. As the needle nears its full stroke, the twister
hook begins rotating. The twister hook catches the end of the ribbon held in the
holder/shear, and the part of the ribbon that is wrapped around the bag neck by the
needle. As the hook twists the ribbon together, the holder/shear transfers to cut and hold
the part of the ribbon held by the needle, and simultaneously releases the end of the twist
tie. The twister hook completes its selectable four or five rotations while the needle returns
to the home position, releasing the bag stop. After the twister hook has tightly secured
the neck of the bag, it reverses rotation for one revolution to discharge the tie from the
throat of the hook. The tied package is then carried away by the conveyor.