Dual-Oil Unclamping: HINAKA's Next-Generation BPT-D and BPF-D Series

A new generation of tool-change unclamping runs hydraulic oil on both the forward and the return stroke, eliminating the trapped air and moisture that have long troubled horizontally mounted unclamping cylinders. Meet HINAKA's Dual-Oil BPT-D and BPF-D series.

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I. The Problem With Air on the Return Stroke

A standard unclamping cylinder pressurises with oil on the forward stroke and returns on air. In most orientations this works well, but two situations expose its limits: horizontal mounting, where trapped air can destabilise pressure and shorten the stroke, and humid or coolant-heavy environments, where moisture entering on the air side eventually causes rust inside the cylinder.

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II. Both Strokes Run on Oil

The Dual-Oil design removes air from the circuit entirely. Both the forward and the return stroke are driven by hydraulic oil, so no air — and no moisture carried by air — ever enters the spindle-side cylinder.

• Sealed twin tank: the open oil cup used on standard units is replaced by a sealed twin tank, which can be mounted away from the spindle and at any angle — not only directly above the cylinder.
• Automatic self-balancing: when the machine is shut down and the air supply is cut, the two tank levels balance automatically. No manual bleeding is required. (Patent pending.)
• DV / DH mounting: BPT-D and BPF-D are available as DV (vertical) or DH (horizontal), covering both orientations without compromise.

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III. Where It Matters Most

Dual-Oil is the right choice wherever a standard unclamping cylinder's air-return side is the weak point:

• Horizontal machining centres, where trapped air is most likely to destabilise the unclamping stroke.
• Coolant-heavy or humid production environments, where moisture ingress on the air side shortens seal and cylinder life.
• Machines that stand idle for long periods, where the automatic level-balancing removes a maintenance step every time the air is reconnected.

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IV. BPT-D and BPF-D at a Glance

Choose BPT-D for belt- and gear-driven spindles, and BPF-D (paired with a HUC hydraulic cylinder) for direct-drive and through-spindle-coolant spindles. Tell us your spindle type and model, mounting orientation and required drawbar force, and we will size the unit for you.

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