Precautions for All Safety Limit Switches
Note:
The above y values indicate the ratio ranges based on TT (total
travel). Therefore, the optimum pressing distance of the dog is
between 50% and 80% (or 50% and 70%).
2.
Overtravel Dog
If the speed of the overtravel dog is comparatively high, make the rear
edge of the object smooth at an angle of 15
q
to 30
q
or make it in the
shape of a quadratic curve. Then lever shaking will be reduced.
Note:
The above y values indicate the ratio ranges based on TT (total
travel). Therefore, the optimum pressing distance of the dog is
between 50% and 80% (or 50% and 70%).
Plunger Models
If the dog overrides the actuator, the front and rear of the dog may be
the same in shape, provided that the dog is not designed to be
separated from the actuator abruptly.
Stroke Settings vs. Dog Movement Distance
x
The following provides information on stroke settings based on the
movement distance of the dog instead of the actuator angle.
The following is the optimum stroke of the Limit Switch.
Optimum stroke: PT + {Rated OT x (0.7 to 1.0)}
The angle converted from the above:
T
1
+
T
2
x
The movement distance of the dog based on the optimum stroke is
expressed by the following formula.
Movement distance of dog
x
The distance between the reference line and the bottom of the dog
based on the optimum stroke is expressed by the following formula.
Dog Surface
x
The surface of dog touching the actuator should be 6.3 S in quality
and hardened at approximately HV450.
For smooth operation of the actuator, apply molybdenum disulfide
grease to the actuator and the dog touching the actuator.
Others
x
When using the Limit Switch with a long lever or long rod lever,
make sure that the lever is in the downward direction.
Dog speed: 0.5 m/s
d
V
d
2 m/s (High Speed)
T
I
V max. (m/s)
y
45
q
45
q
0.5
0.5 to 0.8 (TT)
50
q
40
q
0.6
60
q
to 55
q
30
q
to 35
q
1.3
0.5 to 0.7 (TT)
75
q
to 65
q
15
q
to 25
q
2
Dog speed: 0.5 m/s max.
I
V max. (m/s)
y
30
q
0.4
0.8 (TT)
80% of total travel
45
q
0.25
60
q
0.1
60
q
to 90
q
0.05 (low speed)
Dog speed: 0.5 m/s min.
T
I
V max. (m/s)
y
45
q
45
q
0.5
0.5 to 0.8 (TT)
50
q
40
q
0.6
60
q
to 55
q
30
q
to 35
q
1.3
0.5 to 0.7 (TT)
75
q
to 65
q
15
q
to 25
q
2
Roller Plunger
I
V max. (m/s)
y
30
q
0.25
0.6 to 0.8 (TT)
20
q
0.5
0.5 to 0.7 (TT)
Change lever set angle (
θ
) according
to dog angle (
φ
)
φ
Lever set vertically
φ
φ
60
°
max.
15 to 30
°
φ
φ
70% to 100% of rated OT
PT: Pretravel
OT: Overtravel
Dog
φ:
Dog angle
θ:
Optimum stroke angle
R: Actuator length
X: Dog movement distance
φ
φ
Dog
Reference line
Mounting hole
a: Distance between reference line and actuator fulcrum
b: R cos
θ
r: Roller radius
Y: Distance between reference line and bottom of dog
Y
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