Westfield Fasteners Product Specification:

DIN 3021 - Spring band clamp

This product guide contains the specification for Spring Band Clamps, a series of standard parts available from Westfield Fasteners. The basis of this specification is the internationally recognised DIN standard DIN 3021.

Product Description

Spring band clamps are a one piece, bolt free hose clamp made from hardened spring steel. They are designed to be used with hose systems where temperatures can fluctuate significantly. The shape of the spring band clamp will allow the clamp to continue to apply an even and consistent radial clamping force, within a temperature range of -40°C to +120°C. These spring band clamps are suitable for heavy duty applications.

The clamp is opened by squeezing the two ears together. This can be done with pliers or there are specific tools available. The steel clamps are finished with layers of a black chrome (Vl) free coating, which contains zinc.

Scope of the DIN Standard

DIN 3021 specifies the characteristics for this spring band clamp design, made from hardened spring steel for sizes from 13mm to 90mm in diameter. The diameter given (nominal diameter) is the optimum hose outside diameter. The nominal diameter will not be equivalent to the diameter shipped.

Table 1, with figure 1 gives part dimensions and relevant tolerances. Table 2 gives the 3 directional clamping forces of each clip, whilst table 3 gives the same forces in 4 directions.

Table 1: Dimensions & Tolerances according to DIN 3021

Nominal Diameter, d_n	Delivery Diameter, d_a	Fully Open Diameter, d₀	Material Thickness, s+/-0.4	Clamp Width, c+/-0.3	a, max	b, max	e, +/-0.7	g, +/-0.7	h, max	Gap Size
13	12	14.2	0.8	12	9	10	7	5.8	40	0.09
14	13.3	15.8
15	14	16.5
16	14.9	17.5
17	15.6	18.5
18	16	19
19	17.8	20.2	1.3
20	18.4	21.6
21	19.4	22.5
22	20.5	24.2
23	21	24.7
24	22	26
25	23.5	26.8
26	24.3	28	1.7	60
27	25.2	29
28	26.1	30.2
29	27	31.5
30	28	32.5
31	28.7	33.5
32	29.5	34.5
33	30	35.5
34	30.6	36.4
35	31.5	38
36	32.5	39
37	33.5	40.3
38	34.5	41.5
39	35	42
40	35.5	42.5
41	36.5	43.5	2.1	0.12
42	37.5	44.5
43	37.9	45.5
44	38.5	46.5
45	39.5	47.5
46	40.5	48.5
47	41.5	50
48	42	51
49	42.5	52	72
50	43.5	53
51	44	54

Nominal Diameter, d_n

Delivery Diameter, d_a

Fully Open Diameter, d₀

Material Thickness, s+/-0.4

Clamp Width, c+/-0.3

a, max

b, max

e, +/-0.7

g, +/-0.7

h, max

Gap Size

14.2

0.8

5.8

0.09

13.3

15.8

16.5

14.9

17.5

15.6

18.5

17.8

20.2

1.3

18.4

21.6

19.4

22.5

20.5

24.2

24.7

23.5

26.8

24.3

1.7

25.2

26.1

30.2

31.5

32.5

28.7

33.5

29.5

34.5

35.5

30.6

36.4

31.5

32.5

33.5

40.3

34.5

41.5

35.5

42.5

36.5

43.5

2.1

0.12

37.5

44.5

37.9

45.5

38.5

46.5

39.5

47.5

40.5

48.5

41.5

42.5

43.5

Table 1: Dimensions & Tolerances according to DIN 3021 Continued

Nominal Diameter, d_n	Delivery Diameter, d_a	Fully Open Diameter, d₀	Material Thickness, s+/-0.4	Clamp Width, c+/-0.3	a, max	b, max	e, +/-0.7	g, +/-0.7	h, max	Gap Size
52	45	54.9	2.1	12	9	10	7	5.8	72	0.12
53	46	55.8
54	46.5	56.9
55	47	58
60	51.5	63	2.6	0.15
65	57.5	68
70	61.5	73
75	66	78
80	70	83	110
85	74	88
90	79	93

Nominal Diameter, d_n

Delivery Diameter, d_a

Fully Open Diameter, d₀

Material Thickness, s+/-0.4

Clamp Width, c+/-0.3

a, max

b, max

e, +/-0.7

g, +/-0.7

h, max

Gap Size

54.9

2.1

5.8

0.12

55.8

46.5

56.9

51.5

2.6

0.15

57.5

61.5

110

Nominal Diameter D_n mm	F-3 point N Min
13	100
14
15	130
16	160
17
18	200
19
20
21
22
23	230
24

Nominal Diameter
D_n
mm

F-3 point
N
Min

100

130

160

200

230

Nominal Diameter D_n mm	F-3 point N Min
25	250
26
27	280
28	300
29
30
31
32
33
34
35
36
37
38
39
40
41	340
42
43
44
45	350
46
47
48	410
49
50
51
52
53
54	430
55
60
65	370
70
75	330
80	300
85
90

Nominal Diameter
D_n
mm

F-3 point
N
Min

250

280

300

340

350

410

430

370

330

300

Nominal Diameter D_n mm	F_x N min	F_y N min	ΔF = F_x - F_y N
13	220	170	-10 to 140
14
15
16
7
18	350	280	-10 to 180
19
20
21
22
23
24
27	440	390	0 to 220
28
29
30
31
32
33
34
35
36
37
38
39
40

Nominal Diameter
D_n
mm

F_x
N
min

F_y
N
min

ΔF = F_x - F_y
N

220

170

-10 to 140

350

280

-10 to 180

440

390

0 to 220

Nominal Diameter D_n mm	F_x N min	F_y N min	ΔF = F_x - F_y N
13	220	170	-10 to 140
14
15
16
7
18	350	280	-10 to 180
19
20
21
22
23
24
27	440	390	0 to 220
28
29
30
31
32
33
34
35
36
37
38
39
40

Nominal Diameter
D_n
mm

F_x
N
min

F_y
N
min

ΔF = F_x - F_y
N

220

170

-10 to 140

350

280

-10 to 180

440

390

0 to 220

DIN 3021 - Spring band clamp

Figure 1: Spring band clamp

Table 1: Dimensions & Tolerances according to DIN 3021

Table 1: Dimensions & Tolerances according to DIN 3021 Continued

Figure 2: 3-Channel Clamping Force FORM A

Table 2: 3-Channel Clamping force for FORM A with width of c=12

Table 2: 3-Channel Clamping force for FORM A with width of c=12 Continued

Figure 3: 4-Channel Clamping Force FORM A

Table 3: 4-Channel Clamping force for FORM A with width of c=12

Table 3: 4-Channel Clamping force for FORM A with width of c=12 Continued

Figure 4: Pre-Selection of the Nominal Diameter

Figure 5: Area of Application Equation for Calculating the D_min and for D_Max

Nominal Diameter D_n mm	F-3 point N Min
25	250
26	250
27	280
28	300
29
30
31
32
33
34
35
36
37
38
39
40
41	340
42
43
44
45	350
46
47
48	410
49
50
51
52
53
54	430
55
60
65	370
70	370
75	330
80	300
85
90

Nominal Diameter D_n mm	F-3 point N Min
25	250
26	250
27	280
28	300
29
30
31
32
33
34
35
36
37
38
39
40
41	340
42
43
44
45	350
46
47
48	410
49
50
51
52
53
54	430
55
60
65	370
70	370
75	330
80	300
85
90

DIN 3021 - Spring band clamp

Figure 1: Spring band clamp

Table 1: Dimensions & Tolerances according to DIN 3021

Table 1: Dimensions & Tolerances according to DIN 3021 Continued

Figure 2: 3-Channel Clamping Force FORM A

Table 2: 3-Channel Clamping force for FORM A with width of c=12

Table 2: 3-Channel Clamping force for FORM A with width of c=12 Continued

Figure 3: 4-Channel Clamping Force FORM A

Table 3: 4-Channel Clamping force for FORM A with width of c=12

Table 3: 4-Channel Clamping force for FORM A with width of c=12 Continued

Figure 4: Pre-Selection of the Nominal Diameter

Figure 5: Area of Application Equation for Calculating the Dmin and for DMax

Figure 5: Area of Application Equation for Calculating the D_min and for D_Max

Nominal Diameter D_n mm	F-3 point N Min
25	250
26	250
27	280
28	300
29
30
31
32
33
34
35
36
37
38
39
40
41	340
42
43
44
45	350
46
47
48	410
49
50
51
52
53
54	430
55
60
65	370
70	370
75	330
80	300
85
90