The Tokyo Keiki (formerly Tokimec) FN-4-20-JA-J is an industrial-grade, inline-mounted one-way restrictor valve designed for precision speed and flow control in high-pressure hydraulic circuits. By combining a calibrated throttling orifice and a robust, low-cracking-pressure check valve within a single compact body, this valve offers complete control over actuator speeds (such as cylinders or hydraulic motors) without requiring complex multi-valve assemblies.
During metered operation, turning the adjustment screw clockwise restricts the fluid pathway, providing a dependable, linear adjustment curve. In the opposite direction, the internal poppet opens fully, allowing the fluid to bypass the needle restriction with minimal pressure drop.
Core Technical Features & Advantages
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Linear Metering Control: The standard tapered needle geometry is optimized to eliminate sudden flow spikes, providing predictable throttling from minimum to maximum flow limits.
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Low-Pressure Drop Reverse Flow: Designed with a generous internal bypass channel and check valve assembly to minimize energy loss and heat generation during return strokes.
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Tamper-Resistant Locking Option: The slotted screw adjuster mechanism is paired with a heavy-duty locknut, ensuring the flow setting remains locked against line pulses or physical tampering.
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Rugged, Leak-Free Construction: Built using high-density castings and precision-ground inner elements to ensure reliable zero-leak tracking across long-term duty cycles.
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Space-Saving Inline Subplate/Threaded Interface: Compact physical architecture allows it to fit effortlessly into tight machine manifold spaces or complex plumbing schemes.
Primary Applications
The FN-4 series is standard equipment globally for precision metering applications, particularly within high-end manufacturing platforms:
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Speed control for plastic injection molding ejectors and cores
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Feed-rate regulation in metal cutting and CNC machine tools
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Counter-balance and deceleration circuits in material handling lifts
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General hydraulic power units (HPUs) requiring manual circuit fine-tuning
Technical Specifications Table
| Parameter | Value / Specification |
| Brand Name | Tokyo Keiki (Tokimec) |
| Model Code | FN-4-20-JA-J / Series 20 |
| Valve Type | One-Way Restrictor Valve (with Check Valve) |
| Throttling Element | Tapered Needle (Standard Type) |
| Adjustment Interface | Slotted Screw Adjustment |
| Fluid Media | Mineral Oil / Water-Glycol Based Fluids |
| Body Material | High-Strength Cast Iron / Steel Inner Components |
| Mounting Orientation | Unrestricted / Flexible Mounting |
