F35 Cupla
Quick couplings
The Nitto Kohki F35 Cupla is a flat-face quick-release coupling in steel with FKM seals, available as plugs (P types) and sockets (S types) in nominal sizes 2, 3, 4, 6 and 8. The flat-face design prevents hydraulic fluid from escaping when connecting or disconnecting, eliminating oil loss and minimising air ingestion into the circuit. Steel construction makes the F35 Cupla suitable for elevated operating pressures and mechanically demanding environments.
FKM seals provide resistance to a wide range of hydraulic fluids, mineral oils and synthetic media. The leak-free connection under the flat-face principle makes this range particularly suited to environmentally sensitive or hygiene-critical processes where fluid spillage is unacceptable.
| Part number | Type | Nominal size |
|---|---|---|
| F35-2P | Plug | 2 |
| F35-3P | Plug | 3 |
| F35-4P | Plug | 4 |
| F35-6P | Plug | 6 |
| F35-8P | Plug | 8 |
| F35-2S | Socket | 2 |
| F35-3S | Socket | 3 |
| F35-4S | Socket | 4 |
| F35-6S | Socket | 6 |
| F35-8S | Socket | 8 |
Typical applications: Hydraulic quick-connect couplings on construction machinery and attachments, tool changes on presses and injection moulding machines, hydraulic test benches, environmentally sensitive installations where leak-free coupling is required, and mobile hydraulic power units.
Technical data from the manufacturer catalogue
| Series | FLATFACE CUPLA F35 |
|---|---|
| Body material | Special steel (Nickel plated) |
| Seal material | Fluoro rubber (FKM) |
| Max working pressure | 35.0 MPa {357 kgf/cm2, 350 bar, 5080 PSI} |
| Working temperature | Fluoro rubber (FKM): -20 °C to +180 °C |
| Valve structure | Two-way shut-off (Spill Reduction) |
| Applicable fluids | Hydraulic oil |
| Vacuum service | Not suitable for vacuum application in either connected or disconnected condition. |
| Size range | Thread 1/4 inch, 3/8 inch, 1/2 inch, 3/4 inch, 1 inch |
| Catalogue page | C01en-b, 107 |
Operating principle
- Flat contact face design reduces spill upon disconnection.
- Flat contact face design makes it easy to clean dust and foreign matter adhered on the surface of coupling so as to prevent them from entering inside and thus causing faulty operation of connection or disconnection.
- Flat contact face design minimizes air admixture during connection to keep the possible malfunction of equipment caused by the air bubbles in the hydraulic line at minimum level.
- Push-to-connect operation.
- Separation prevention mechanism is easily locked by turning the sleeve after connection. It prevents accidental disconnection even when vibration or impact is applied to CUPLA.
- The special design reduces pressure loss considerably, and especially suited to hydraulic applications in which big flow is needed. Both socket and plug have built-in automatic shut-off valves that prevent fluid spill out on disconnection.
- For hydraulic pressures up to 35.0 MPa {357 kgf/cm2} with flat contact face.
All models of the series
P - Female thread
| Model | Coupling part | Application | Steel (g) | L | C | T | øH(WAF) | øoD |
|---|---|---|---|---|---|---|---|---|
| F35-2P | Plug | R 1/4 | 106 | 58 | 18.8 | Rc 1/4 | 19 | 21.5 |
| F35-3P | Plug | R 3/8 | 190 | 67.5 | 24 | Rc 3/8 | 24 | 27 |
| F35-4P | Plug | R 1/2 | 290 | 78 | 28.5 | Rc 1/2 | 27 | 31.7 |
| F35-6P | Plug | R 3/4 | 460 | 84.5 | 31 | Rc 3/4 | 36 | 40 |
| F35-8P | Plug | R1 | 1000 | 108 | 39 | Rc 1 | 46 | 50 |
S - Female thread
| Model | Coupling part | Application | Steel (g) | L | T | øH(WAF) | øoD |
|---|---|---|---|---|---|---|---|
| F35-2S | Socket | R 1/4 | 182 | (57.5) | Rc 1/4 | 26×ø28.5 | (28) |
| F35-3S | Socket | R 3/8 | 320 | (70) | Rc 3/8 | 30 | (34) |
| F35-4S | Socket | R 1/2 | 490 | (78) | Rc 1/2 | 36 | (41) |
| F35-6S | Socket | R 3/4 | 815 | (85) | Rc 3/4 | 46×ø50 | (49) |
| F35-8S | Socket | R1 | 1520 | (104) | Rc 1 | 55 | (63) |
Dimensions in millimetres. Values in brackets apply in the connected condition.
Legend: L = overall length; H = width across flats or outside dimension; D = socket outside diameter; A = hose barb length; C = sleeve dimension; T = thread or barb size; B = bore
Series comparison
| Series | Max working pressure | Size range | Valve structure | Applicable fluids |
|---|---|---|---|---|
| HSP-DC CUPLA | 206 bar | 1/4 inch to 1 inch (applicable pipe size 1/4 inch, 3/8 inch, 1/2 inch, 3/4 inch, 1 inch) | Two-way shut-off | Hydraulic oil |
| FLATFACE CUPLA F35 | 350 bar | Thread 1/4 inch, 3/8 inch, 1/2 inch, 3/4 inch, 1 inch | Two-way shut-off (Spill Reduction) | Hydraulic oil |
| FLATFACE CUPLA FF | 350 bar | 3/8 inch, 1/2 inch, 3/4 inch, 1 inch (thread) | Two-way shut-off (Spill Reduction) | Hydraulic oil |
| In-Line PURGE ADAPTER | 350 bar | PAD-2: R 1/4. PAD-3FM: R 3/8 x Rc 3/8. PAD-4FM: R 1/2 x Rc 1/2. PAD-6FM: R 3/4 x Rc 3/4. PAD-8FM: R 1 x Rc 1. | - | Hydraulic oil |
Choose FLATFACE CUPLA F35 when the line is hydraulic and the working pressure reaches 35.0 MPa {357 kgf/cm2}; the sibling series in this category are rated 1.0 to 1.5 MPa {10 to 15 kgf/cm2} and do not cover that range. Among them only COMPACT ZEROSPILL CUPLA is likewise two-way shut-off with spill reduction, but at 1.0 MPa {10 kgf/cm2}, while HI CUPLA BL, NUT CUPLA, LOCK CUPLA 200, HI CUPLA Two Way Type, PURGE HI CUPLA, PURGE LINE CUPLA and the ROTARY versions are one-way shut-off. For low pressure duties where shut-off on one side is sufficient, one of those series is the better choice.
Body and seal materials
| Body material |
|---|
| Special steel (Nickel plated) |
| Seal material | Mark | Working temperature | Remarks |
|---|---|---|---|
| Fluoro rubber | FKM | -20 °C to +180 °C | Standard material |
Further catalogue data
| Note | Value |
|---|---|
| Pressure unit table | Working pressure 35.0 MPa, 357 kgf/cm2, 350 bar, 5080 PSI |
| Maximum tightening torque in Nm {kgf.cm} | 1/4 inch: 28 {286}, 3/8 inch: 40 {408}, 1/2 inch: 80 {816}, 3/4 inch: 150 {1530}, 1 inch: 250 {2550} |
| Flow direction | Fluid flow can be bi-directional when socket and plug are connected. |
| Minimum cross-sectional area in mm2 | F35-2SP: 21.2, F35-3SP: 32.2, F35-4SP: 78.5, F35-6SP: 149.6, F35-8SP: 227.0 |
| Admixture of air on connection in mL (may vary depending upon the usage conditions) | F35-2SP: 0.1, F35-3SP: 0.1, F35-4SP: 0.2, F35-6SP: 0.3, F35-8SP: 0.4 |
| WAF | WAF stands for width across flats. |
| Flow rate | Flow rate - pressure loss characteristics are printed only as a graph on page 108, for F35-2S×F35-2P, F35-3S×F35-3P, F35-4S×F35-4P, F35-6S×F35-6P and F35-8S×F35-8P. Test conditions: fluid hydraulic oil, fluid viscosity 32×10-6 m2/s, density 0.87×103 kg/m3. Graph range 1 to 1000 L/min against 0.01 {0.1} to 1.0 {10} MPa {kgf/cm2} pressure loss. No numeric flow or Cv values are printed. |
Interchangeability and size groups
Socket and plug of different sizes cannot be connected.
Safety and application notes
- Do not connect / disconnect CUPLA when pressure is applied or remaining.
- Before use, please be sure to read "Safety Guide" described at the end of this book and "Instruction Sheet" that comes with the products.
All technical data on this page is taken from the Nitto Kohki general catalogue Quick Connect Couplings C01en-b, page 107. The complete catalogue is available for download on this page.
