This
type of diaphragm has a rectangular bead molded inside
the cylinder wall. This design requires the smallest hardware
diameter of any diaphragm type. Since clamping and sealing
in this style is against the inside wall of the cylinder,
the stroke capability is restricted to the lower half
of the diaphragm.
Dimensions and Tolerances
Inches
mm
Inches
mm
Inches
mm
Inches
mm
Cylinder Diameter
1.00-2.50
25-64
2.51-4.00
64-102
4.01-8.00
102-205
8.01 & up
205 & up
Height
See available sizes table
Cylinder
Diameter
Tolerances on Cylinder Diameter and Piston Diameter
are ± 0.010 per inch (0.254 mm) of diameter
but the tolerance will be no less than ±
0.010 (0.254 mm) or greater than ± 0.060
(1.52 mm)
Piston
Diameter
Head
& Flange Thickness
.017 ± .004
0.43 ± 0.10
.024 ± .004
0.61 ± 0.10
.035 ± .005
0.89 ± 0.13
.045 ± .007
1.14 ± 0.18
Wall
Gauge
.017 ± .003
0.43 ± 0.08
.024 ± .004
0.61 ± 0.10
.035 ± .005
0.89 ± 0.13
.045 ± .007
1.14 ± 0.18
Flash
Projection
.025 Max.
0.64 Max.
.035 Max.
0.89 Max.
.040 Max.
1.02 Max.
.056 Max.
1.42 Max.
Flash
Thickness
.025 Max.
0.64 Max.
.035 Max.
0.89 Max.
.040 Max.
1.02 Max.
.056 Max.
1.42 Max.
Flange
Radius
.031
0.79
.047
1.19
.063
1.60
.063
1.60
Bead
Width
.080 ± .003
2.03 ± 0.08
.100 ± .003
2.51 ± 0.08
.120 ± .003
3.05 ± 0.08
.160 ± .003
4.06 ± 0.08
Bead
Height
.150 ± .005
3.81 ± 0.13
.200 ± .005
5.08 ± 0.13
.260 ± .005
6.60 ± 0.13
.300 ± .007
7.62 ± 0.18
Hardware
Recommendations
Stamped
Retainer Plate Sealing Via Axial Compression
Cast Machined
Retainer Plate Sealing Via Radial Compression
Cylinder Diameter
Bead Groove Width = W
Bead Groove Height = H
Lip Radius = R1
Piston Corner Radius = R2
Lip Clearance = C
(Inches)
(mm)
(Inches)
(mm)
(Inches)
(mm)
(Inches)
(mm)
(Inches)
(mm)
Sidewall Thickness + .003
1.00-2.50
25-64
.080
2.03
1.50
3.81
.030
0.76
.063
1.60
2.51-4.00
64-102
.100
2.45
.200
5.08
.040
1.02
.094
2.39
4.01-8.00
102-205
.120
3.05
.260
6.60
.050
1.27
.125
3.18
8.01 and up
205 and up
.160
4.06
.300
7.62
.060
1.52
.188
4.78
Available Sizes
Dia•Com
Part No,
Cylinder
Diameter
Piston
Diameter
Height
Gauge
Approx.
Convolution
Width
Effective
Pressure
Area
Maximum
Half-Stroke
(Inches)
(mm)
(Inches)
(mm)
(Inches)
(mm)
(Inches)
(mm)
(Inches)
(mm)
(Inches)
*
(Inches)
(mm)
OB-250-178
2.50
64
2.13
54
1.78
45
.035
0.89
.185
4.7
4.21
27.1
1.39
35.3
OB-250-225
2.50
64
2.13
54
2.25
57
.035
0.89
.185
4.7
4.21
27.1
1.86
47.2
OB-250-258
2.50
64
2.06
52
2.58
66
.035
0.89
.220
5.6
4.08
26.3
2.14
54.4
OB-300-284
3.00
76
2.56
65
2.84
72
.035
0.89
.220
5.6
6.07
39.1
2.39
60.7
OB-300-284
3.00
76
2.63
67
2.84
72
.035
0.89
.185
4.7
6.22
40.1
2.45
62.2
OB-306-338
3.06
78
2.63
67
3.38
86
.035
0.89
.215
5.5
6.35
41.0
2.95
74.9
OB-362-340
3.62
92
3.12
79
3.40
86
.035
0.89
.250
6.4
8.92
57.5
2.33
59.2
OB-362-351
3.62
92
3.12
79
3.51
89
.035
0.89
.250
6.4
8.92
57.5
2.44
62.0
OB-363-406
3.62
92
3.12
79
4.06
103
.035
0.89
.250
6.4
8.92
57.5
3.09
78.5
OB-388-406
3.88
99
3.38
86
4.06
103
.035
0.89
.250
6.4
10.34
66.7
3.09
78.5
OB-388-413
3.88
99
3.33
85
4.13
105
.035
0.89
.275
7.0
10.20
65.8
3.12
79.2
OB-416-195
4.16
106
3.66
93
1.95
50
.035
0.89
.250
6.4
12.00
77.4
0.95
24.1
OB-416-353
4.16
106
3.66
93
3.53
90
.035
0.89
.250
6.4
12.00
77.4
2.53
64.3
OB-416-481
4.16
106
3.66
93
4.81
122
.035
0.89
.250
6.4
12.00
77.4
3.81
96.8
OB-475-374
4.75
121
4.25
108
3.74
95
.035
0.89
.250
6.4
15.90
102.6
2.61
66.3
OB-475-541
4.75
121
4.25
108
5.41
137
.035
0.89
.250
6.4
15.90
102.6
4.28
108.7
OB-700-414
7.00
178
6.50
165
4.14
105
.040
1.02
.250
6.4
35.77
230.8
3.01
76.5
*Metric effective pressure
area shown in square centimeters.
