<s>
A	O
rigid	B-Algorithm
chain	I-Algorithm
actuator	I-Algorithm
,	O
known	O
variously	O
as	O
a	O
linear	O
chain	O
actuator	O
,	O
push-pull	O
chain	O
actuator	O
,	O
electric	O
chain	O
actuator	O
or	O
column-forming	O
chain	O
actuator	O
,	O
is	O
a	O
specialized	O
mechanical	O
linear	B-Algorithm
actuator	I-Algorithm
used	O
in	O
window	O
operating	O
,	O
push-pull	O
material	O
handling	O
and	O
lift	O
applications	O
.	O
</s>
<s>
Rigid	B-Algorithm
chain	I-Algorithm
actuators	I-Algorithm
function	O
as	O
rack	O
and	O
pinion	O
linear	B-Algorithm
actuators	I-Algorithm
that	O
use	O
articulated	O
racks	O
.	O
</s>
<s>
Rigid	B-Algorithm
chain	I-Algorithm
actuators	I-Algorithm
use	O
limited-articulation	O
chains	O
,	O
usually	O
resembling	O
a	O
roller	O
chain	O
,	O
that	O
engage	O
with	O
pinions	O
mounted	O
on	O
a	O
drive	O
shaft	O
within	O
a	O
housing	O
.	O
</s>
<s>
Rigid	B-Algorithm
chain	I-Algorithm
actuators	I-Algorithm
are	O
generally	O
driven	O
by	O
electric	O
motors	O
.	O
</s>
<s>
The	O
development	O
of	O
efficient	O
rigid	B-Algorithm
chain	I-Algorithm
actuators	I-Algorithm
broadened	O
the	O
use	O
of	O
chain	O
actuation	O
for	O
industrial	O
applications	O
.	O
</s>
<s>
Small	O
scale	O
rigid	B-Algorithm
chain	I-Algorithm
actuators	I-Algorithm
are	O
used	O
as	O
building	O
hardware	O
,	O
incorporated	O
into	O
windows	O
,	O
door	O
and	O
hatches	O
as	O
motorized	O
open/close	O
mechanisms	O
.	O
</s>
<s>
Rigid	B-Algorithm
chain	I-Algorithm
actuators	I-Algorithm
are	O
also	O
used	O
as	O
the	O
lifting	O
columns	O
in	O
performing	O
arts	O
facilities	O
,	O
incorporated	O
in	O
stage	O
,	O
orchestra	O
and	O
seating	O
platform	O
lift	O
systems	O
.	O
</s>
<s>
The	O
primary	O
distinction	O
between	O
types	O
of	O
rigid	B-Algorithm
chain	I-Algorithm
actuator	I-Algorithm
is	O
whether	O
the	O
actuating	O
member	O
is	O
formed	O
from	O
a	O
single	O
chain	O
or	O
from	O
a	O
pair	O
of	O
interlocking	O
chains	O
in	O
a	O
back-to-back	O
arrangement	O
,	O
like	O
a	O
zipper	B-Application
.	O
</s>
<s>
Rigid	B-Algorithm
chain	I-Algorithm
actuators	I-Algorithm
were	O
developed	O
from	O
“	O
chain	O
rammers	O
”	O
that	O
used	O
a	O
single	O
“	O
ram	O
chain	O
”	O
thrust	O
from	O
a	O
magazine	O
to	O
load	O
heavy-caliber	O
ordnance	O
into	O
the	O
breech	O
of	O
a	O
cannon	O
.	O
</s>
<s>
Developed	O
more	O
than	O
a	O
century	O
ago	O
,	O
his	O
rammer	O
still	O
bears	O
a	O
strong	O
resemblance	O
to	O
many	O
modern	O
rigid	B-Algorithm
chain	I-Algorithm
actuators	I-Algorithm
.	O
</s>
<s>
The	O
zipper	B-Application
action	O
of	O
back-to-back	O
interlocking	O
chains	O
provided	O
guideless	O
chain	O
travel	O
regardless	O
of	O
orientation	O
and	O
path	O
of	O
travel	O
.	O
</s>
