| Every motorized
Electric Cylinder must be controlled so that power to the motor
is turned off and the brake engaged before the limits of mechanical
travel are reached.
The ActionJac™ rotary limit switch senses
extension shaft rotation and provides switch contact closures that
can be used to control motors.
This sturdy, durable assembly is available
with two or four circuits or two circuits and a potentiometer. Each
circuit has a separate rotating cam that actuates a high quality
switch. The switch actuation may be individually and infinitely
adjusted anywhere within the travel of the cylinder.
These assemblies contain gear reducers with
ratios that vary according to the model and travel of the jack.
Nook selects ratios that result in maximum cam rotation for best
accuracy, repeatability and minimum hysteresis. In most cases, with
full travel of the actuator, the cam will rotate 3/8 to 7/8 of a
revolution to actuate a switch. In the event that the cam continues
to rotate, the switch returns to its original state after approximately
25° of rotation, with no damage to the limit switch assembly.
A 2-circuit switch assembly is useful for
limiting the maximum and minimum extension. A 4-circuit assembly
gives the possibility of additional signals for other user purposes.
The potentiometer version is used to provide an analog signal for
sensing cylinder position.
Single Pole Double Throw (SPDT) switches are
standard and Double Pole Double Throw (DPDT) switches are optional.
These assemblies are dust protected and meet NEMA 4 and 5 standards
for oil and water tightness.
An ActionJac™ Rotary Limit Switch assembly
is mounted to the extension shaft side of the ActionJac™ Worm Gear
Screw Cylinder opposite the motor. A rotary limit switch is available
for ActionJac™ Electric Cylinder Series DD-25 and RAD-25 and larger.
Most cylinder models have close and extended mounts for the switches
to provide clearance around the switch housing. See the charts below
for dimensions.
Switches are factory installed to assure proper
assembly in the correct orientation for the specified mounting position.
CAUTION: Limit switches are not adjusted at the factory. Switches
must be set after installation. CAUTION: Limit switches are not
adjusted at the factory. Switches should be set during installation. |
