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Limit Switches

Limit Switch are basic switches that have been encased to protect them from external forces, water, oil, and dirt. Many models are available, such as those resistant to head, cold, or corrosion, as well as high-precision models.

Introduction Features
Principles Classifications
Engineering Data Further Information
Explanation of Terms Troubleshooting

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Limit Switch Actuator Type and Selection Methods

Roller leverSmall to
★★★The stroke in the operating direction is as
large as 45° to 90°, the actual angle of
which varies with the model. The lever can
be set in any angle. Highly sensitive models
with small PT values and wide angle models
with large OT values are available. These
models are applied to a wide range of
applications including object positioning and
roller lever
Small to
★★Dogs are detected roughly by making use
of the characteristics of the roller lever.
The length of the lever is adjustable.
(Countermeasures against lever shaking*4
may be required.)
rod lever
LargeLargeMedium★★★★This lever is convenient when the dogs
are wide or not uniform in size. The OF
required by this lever is smaller than that
of any other rotating actuator used for
Limit Switches. The length of the rod is
adjustable and the rod itself can be bent
easily. (Countermeasures against lever
shaking*4 may be required.)
Fork lever
LargeMediumMedium★★★★★The lever turns by itself when it is
operated to an angle of 55°and the
lever keeps its position at an angle of
90°. A single Dog in reciprocating
operation can actuate the Limit Switch.
Two dogs can be used to actuate two
Limit Switches positioned slightly
different from each other.
PlungerSmallMediumLarge★★★★★★The plunger operated by hydraulic pressure
or air cylinder power detects positions
highly accurately. The plunger must be
installed according to the movement of the
dog so that an incorrect load will not be
imposed on the plunger.
SmallMediumLarge★★★★★★The roller plunger can be operated in a
wide range by employing a cam, Dog,
cylinder, or auxiliary actuator. Position
detection accuracy is high.
Ball plungerSmallMediumLarge★★★★★The tip of the plunger is made of a steel
ball, which can be operated in any direction
with no limitations.
The ball plunger is convenient when the
mounting side is not aligned with the
movement direction of the Dog or the Limit
Switch is actuated by two dogs in X and Y
SmallMediumLarge★★★★★★Unlike roller plungers, the bevel plunger
protects the actuator from abrasion. The
bevel plunger is a hardened plunger with
an edge angle of 120° that ensures
high accuracy and a long life. The bevel
plunger is mainly applied to multiple Limit
Switches for multi-level control of
machining equipment.
Coil springMediumLargeSmallThe coil spring can be operated in any
direction except the axis direction. The
OF required by the coil spring is smaller
than any other actuator used for Limit
Switches. The use of the coil spring is
ideal for the detection of dogs that are
not uniform in size or direction.
The OT is absorbed by the actuator,
thus permitting variations in the dog
Hinge leverLargeMediumSmallThe hinge lever is used with low-speed,
low-torque cams. The lever can be
varied in a variety of shapes according
to the Dog.
Hinge roller
LargeMediumSmallThis lever consists of a hinge lever with
a roller and suitable for a high-speed
cam. (The operating speed must be
within the permissible rate.)
Roller arm
MediumMediumMediumThe roller position can be changed.

Note:Indications for repeat accuracy and shock and vibration resistance are as follows: ★: OK, ★★: Good, ★★★: Excellent, ★★★★: Superior

*1.Panel-mounting models are available (D4E-[]N, SHL, ZC-[]55, and D4MC).

*2.Horizontal roller models are available (D4A-[]N).

*3.Steel wire modes are available (WL). Plastic rod or wire rod models are available (D4C, D4CC, HL-5000, and D4A-[]N).

*4.Lever shaking may cause the actuator to bounce after being actuated and to move to the operating position on the opposite side. This may result in a failure of the Limit Switch.