Stock Drive Products & Sterling Instrument - SDP/SI Datasheets for Constant Force Springs

Constant force springs are a variety of extension spring. A strip of steel with a preset curvature is coiled tightly so that each turn of the strip rests on its inner neighbor. The spring is actuated in a pulling, liner motion with the deflection resistance originating from the material's stiffness and spring construction. Unlike other extension springs, a consistent degree of force is exerted despite the degree of deflection.
Constant Force Springs: Learn more

Product Name Notes
0.13 lb-in Torque, 2500 Cycles Fatique Life, 0.002" Thick, 0.25" Width -- A 3X51-20002
0.34 lb-in Torque, 2500 Cycles Fatique Life, 0.004" Thick, 0.25" Width -- A 3X51-20004
0.65 lb-in Torque, 2500 Cycles Fatique Life, 0.005" Thick, 0.312" Width -- A 3X51-20005
1.13 lb-in Torque, 2500 Cycles Fatique Life, 0.006" Thick, 0.375" Width -- A 3X51-20006
1.81 lb-in Torque, 2500 Cycles Fatique Life, 0.007" Thick, 0.437" Width -- A 3X51-20007
2.65 lb-in Torque, 2500 Cycles Fatique Life, 0.008" Thick, 0.5" Width -- A 3X51-20008
3.87 lb-in Torque, 2500 Cycles Fatique Life, 0.009" Thick, 0.562" Width -- A 3X51-20009
5.50 lb-in Torque, 2500 Cycles Fatique Life, 0.01" Thick, 0.625" Width -- A 3X51-20010
7.06 lb-in Torque, 2500 Cycles Fatique Life, 0.011" Thick, 0.687" Width -- A 3X51-20011
9 lb-in Torque, 2500 Cycles Fatique Life, 0.012" Thick, 0.75" Width -- A 3X51-20012
Constant Force Spring: 0.23 lb Spring Force, 20000 cycles Fatique Life, 16" Band length -- A 3X50-SL04D16
Constant Force Spring: 0.32 lb Spring Force, 13000 cycles Fatique Life, 15" Band length -- A 3X50-SK04D15
Constant Force Spring: 0.36 lb Spring Force, 20000 cycles Fatique Life, 17" Band length -- A 3X50-SL05E17
Constant Force Spring: 0.37 lb Spring Force, 2500 cycles Fatique Life, 10" Band length -- A 3X50-SH03C10
Constant Force Spring: 0.4 lb Spring Force, 13000 cycles Fatique Life, 15" Band length -- A 3X50-SK04E15
Constant Force Spring: 0.43 lb Spring Force, 20000 cycles Fatique Life, 30" Band length -- A 3X50-SL05F30
Constant Force Spring: 0.49 lb Spring Force, 13000 cycles Fatique Life, 16" Band length -- A 3X50-SK05E16
Constant Force Spring: 0.49 lb Spring Force, 2500 cycles Fatique Life, 14" Band length -- A 3X50-SH04C14
Constant Force Spring: 0.52 lb Spring Force, 20000 cycles Fatique Life, 24" Band length -- A 3X50-SL06F24
Constant Force Spring: 0.66 lb Spring Force, 2500 cycles Fatique Life, 14" Band length -- A 3X50-SH04D14
Constant Force Spring: 0.7 lb Spring Force, 20000 cycles Fatique Life, 24" Band length -- A 3X50-SL06G24
Constant Force Spring: 0.71 lb Spring Force, 13000 cycles Fatique Life, 23" Band length -- A 3X50-SK06F23
Constant Force Spring: 0.83 lb Spring Force, 2500 cycles Fatique Life, 14" Band length -- A 3X50-SH04E14
Constant Force Spring: 0.93 lb Spring Force, 20000 cycles Fatique Life, 31" Band length -- A 3X50-SL08G31
Constant Force Spring: 0.95 lb Spring Force, 13000 cycles Fatique Life, 23" Band length -- A 3X50-SK06G23
Constant Force Spring: 1.03 lb Spring Force, 2500 cycles Fatique Life, 15" Band length -- A 3X50-SH05E15
Constant Force Spring: 1.26 lb Spring Force, 13000 cycles Fatique Life, 30" Band length -- A 3X50-SK08G30
Constant Force Spring: 1.46 lb Spring Force, 20000 cycles Fatique Life, 33" Band length -- A 3X50-SL10J33
Constant Force Spring: 1.48 lb Spring Force, 2500 cycles Fatique Life, 21" Band length -- A 3X50-SH06F21
Constant Force Spring: 1.58 lb Spring Force, 13000 cycles Fatique Life, 30" Band length -- A 3X50-SK08J30
Constant Force Spring: 1.97 lb Spring Force, 2500 cycles Fatique Life, 21" Band length -- A 3X50-SH06G21
Constant Force Spring: 1.98 lb Spring Force, 13000 cycles Fatique Life, 32" Band length -- A 3X50-SK10J32
Constant Force Spring: 10.6 lb Spring Force, 2500 cycles Fatique Life, 38" Band length -- A 3X50-SH16P38
Constant Force Spring: 11.7 lb Spring Force, 20000 cycles Fatique Life, 59" Band length -- A 3X50-SL25U59
Constant Force Spring: 11.9 lb Spring Force, 13000 cycles Fatique Life, 57" Band length -- A 3X50-SK25S57
Constant Force Spring: 14.40 lb Spring Force, 20000 cycles Fatique Life 69" Band length -- A 3X50-SL31U69
Constant Force Spring: 15.8 lb Spring Force, 13000 cycles Fatique Life, 57" Band length -- A 3X50-SK25U57
Constant Force Spring: 16.5 lb Spring Force, 2500 cycles Fatique Life, 47" Band length -- A 3X50-SH20R47
Constant Force Spring: 19.6 lb Spring Force, 13000 cycles Fatique Life, 68" Band length -- A 3X50-SK31U68
Constant Force Spring: 19.8 lb Spring Force, 2500 cycles Fatique Life, 47" Band length -- A 3X50-SH20S47
Constant Force Spring: 2.09 lb Spring Force, 20000 cycles Fatique Life, 42" Band length -- A 3X50-SL12K42
Constant Force Spring: 2.37 lb Spring Force, 13000 cycles Fatique Life, 32" Band length -- A 3X50-SK10K32
Constant Force Spring: 2.63 lb Spring Force, 2500 cycles Fatique Life, 28" Band length -- A 3X50-SH08G28
Constant Force Spring: 2.8 lb Spring Force, 20000 cycles Fatique Life, 42" Band length -- A 3X50-SL12P42
Constant Force Spring: 2.84 lb Spring Force, 13000 cycles Fatique Life, 40" Band length -- A 3X50-SK12K40
Constant Force Spring: 24.8 lb Spring Force, 2500 cycles Fatique Life, 48" Band length -- A 3X50-SH25S48
Constant Force Spring: 3.29 lb Spring Force, 2500 cycles Fatique Life, 28" Band length -- A 3X50-SH08J28
Constant Force Spring: 3.5 lb Spring Force, 20000 cycles Fatique Life, 46" Band length -- A 3X50-SL15P46
Constant Force Spring: 3.79 lb Spring Force, 13000 cycles Fatique Life, 40" Band length -- A 3X50-SK12P40
Constant Force Spring: 33 lb Spring Force, 2500 cycles Fatique Life, 48 48" Band length -- A 3X50-SH25U48
Constant Force Spring: 4.12 lb Spring Force, 2500 cycles Fatique Life, 29" Band length -- A 3X50-SH10J29
Constant Force Spring: 4.37 lb Spring Force, 20000 cycles Fatique Life, 46" Band length -- A 3X50-SL15R46
Constant Force Spring: 4.74 lb Spring Force, 13000 cycles Fatique Life, 42" Band length -- A 3X50-SK15P42
Constant Force Spring: 4.95 lb Spring Force, 2500 cycles Fatique Life, 29" Band length -- A 3X50-SH10K29
Constant Force Spring: 40.9 lb Spring Force, 2500 cycles Fatique Life, 58" Band length -- A 3X50-SH31U58
Constant Force Spring: 5.69 lb Spring Force, 13000 cycles Fatique Life, 47" Band length -- A 3X50-SK18P47
Constant Force Spring: 5.83 lb Spring Force, 20000 cycles Fatique Life, 54" Band length -- A 3X50-SL20R54
Constant Force Spring: 5.94 lb Spring Force, 2500 cycles Fatique Life, 36" Band length -- A 3X50-SH12K36
Constant Force Spring: 6.99 lb Spring Force, 20000 cycles Fatique Life, 54" Band length -- A 3X50-SL20S54
Constant Force Spring: 7.92 lb Spring Force, 2500 cycles Fatique Life, 36" Band length -- A 3X50-SH12P36
Constant Force Spring: 8.74 lb Spring Force, 20000 cycles Fatique Life, 59" Band length -- A 3X50-SL25S59
Constant Force Spring: 9.48 lb Spring Force, 13000 cycles Fatique Life, 52" Band length -- A 3X50-SK20S52
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