BD Adjustable Hydraulic Buffers — 6 to 21,000 Nm, Tuned On Site in 12 Steps
The general-purpose industrial shock absorber. Turn the adjustment knob to retune the damping force whenever your load or speed changes — one model can cover several work stations.
What the BD Series Is For
BD is the workhorse of the range. It carries the widest stroke and energy spread of any series we supply, from a 6 Nm M10 unit for a robotic cell to a 21,000 Nm M115 unit for a heavy conveyor stop.
What sets it apart is the external adjustment knob. Twelve discrete steps let you retune the damping force on site, without tools and without removing the buffer. That matters during commissioning, when the real load is rarely the load on the drawing — and it keeps paying off afterwards, because a single model can serve several stations with different weights.
Every BD unit uses a multi-orifice damping stack rather than the single orifice used by most European and American brands. Under identical conditions this produces a lower peak damping force and completes the deceleration in less time.
Internal Coil Spring, Multi-Orifice Damping
Oil is metered through a stack of calibrated orifices as the piston is driven into the cylinder. The viscous resistance converts kinetic energy into heat, which is dissipated through the body. An internal coil spring returns the rod. The multi-orifice layout spreads the pressure drop across the stroke, which flattens the deceleration curve and lowers the peak force your structure has to carry.
Performance &Advantages
Standard operating range -10 °C to 80 °C, extended to -30 °C to 100 °C with the special seal and hydraulic oil package.
0–12 step adjustment
Visible knob, factory set to step 6, retuned on site at any time.
Multi-orifice design
Lower peak damping force and a shorter stopping time than a single-orifice unit of the same size.
M10 to M115
Body and adjustment knob are geometrically matched so the unit stays easy to mount and easy to tune.
Sealing
From M20 upward: polyurethane rod seal plus wiper, running on a high-strength chrome-plated rod.
Side-load bearing
Long front bearing with a DU bushing carries side loads and relaxes the alignment tolerance.
-SP variants
BD25-25SP and BD36-25SP tolerate a 30° side load angle for rotating stations — no adapter needed.
Wide temperature range
-10 °C to 80 °C as standard; -30 °C to 100 °C with the special seal and oil package.
Model Selection
Select by stroke and energy per cycle, then confirm with the maximum energy per hour. If your duty cycle is demanding, send us the numbers and we will run the calculation for you.
| Model | Stroke (mm) | Max Energy/Cycle (Nm) | Max Energy/Hour (Nm/h) | Cylinder Dia. |
|---|---|---|---|---|
| BD10-07(B) | 7 | 6 | 14,500 | M10×1.0 |
| BD12-10(B) | 10 | 16 | 24,500 | M12×1.0 |
| BD12-14(B) | 14 | 22 | 35,500 | M12×1.0 |
| BD14-12(B) | 12 | 28 | 46,500 | M14×1.5 |
| BD16-12(B) | 12 | 33 | 55,000 | M16×1.5 |
| BD20-16(B) | 16 | 55 | 65,000 | M20×1.5 |
| BD25-25(B) | 25 | 220 | 111,000 | M25×1.5 |
| BD25-25(B)-SP | 25 | 220 | 111,000 | M25×1.5 |
| BD25-40(B) | 40 | 300 | 182,000 | M25×1.5 |
| BD25-80(B) | 80 | 390 | 210,000 | M25×1.5 |
| BD27-25(B) | 25 | 220 | 111,000 | M27×3.0 |
| BD27-40(B) | 40 | 300 | 182,000 | M27×3.0 |
| BD30-35(B) | 35 | 390 | 210,000 | M30×1.5 |
| BD33-25(B) | 25 | 500 | 120,000 | M33×1.5 |
| BD33-50(B) | 50 | 500 | 150,000 | M33×1.5 |
| BD36-25(B) | 25 | 550 | 125,000 | M36×1.5 |
| BD36-50(B) | 50 | 550 | 160,000 | M36×1.5 |
| BD42-25(B) | 25 | 700 | 185,000 | M42×1.5 |
| BD42-50(B) | 50 | 1,350 | 255,000 | M42×1.5 |
| BD42-75(B) | 75 | 2,100 | 285,000 | M42×1.5 |
| BD45-25(B) | 25 | 700 | 185,000 | M45×1.5 |
| BD45-50(B) | 50 | 1,350 | 255,000 | M45×1.5 |
| BD45-75(B) | 75 | 2,100 | 285,000 | M45×1.5 |
| BD64-50(B) | 50 | 2,500 | 250,000 | M64×2.0 |
| BD64-100(B) | 100 | 5,000 | 350,000 | M64×2.0 |
| BD64-150(B) | 150 | 7,500 | 450,000 | M64×2.0 |
| BD85-50(B) | 50 | 2,500 | 380,000 | M85×2.0 |
| BD85-90(B) | 90 | 4,300 | 680,000 | M85×2.0 |
| BD85-125(B) | 125 | 6,000 | 1,000,000 | M85×2.0 |
| BD85-165(B) | 165 | 7,500 | 1,300,000 | M85×2.0 |
| BD115-50(B) | 50 | 4,000 | 1,600,000 | M115×2.0 |
| BD115-100(B) | 100 | 8,000 | 1,850,000 | M115×2.0 |
| BD115-150(B) | 150 | 12,000 | 2,200,000 | M115×2.0 |
| BD115-200(B) | 200 | 16,000 | 2,500,000 | M115×2.0 |
| BD115-250(B) | 250 | 21,000 | 2,800,000 | M115×2.0 |
LR long-return and -SP side-load variants are available on selected sizes. Suffix (B) = steel strike head; NB = supplied without strike head.
How to Set the Adjustment Step
- Start at step 0Confirm the knob is at 0 before mounting the buffer, then start the machine.
- Step up one notch at a time0 → 1 → 2 → 3 → 4. Never skip a step.
- Read the stopping behaviourSmooth deceleration with only a soft hiss at the end of travel means the step is correct.
- Too soft?No visible deceleration and a bang at the end of travel — the damping is too light. Increase one step.
- Too hard?The load stops abruptly mid-stroke with a loud report — the damping is too heavy. Decrease one step.
- Lock itOnce the step is right, tighten the locking screw with a hex key. A loose screw lets the nut rotate under impact.
- Still not right?At step 0 still overrunning means the model is too small. At step 12 still stopping hard means it is too large.
Never jump steps
Always step the damping up one notch at a time — 0 → 1 → 2 → 3 → 4. Jumping straight from 0 to 4 damages the buffer.
Installation &Maintenance
- Use the buffer as an end stop.
- Remove the steel strike head.
- Exceed the permitted side load angle.
- Paint the piston rod or the body.
- Place it near acids, solvents or soluble cutting oil.
- Expose it to open flame — the unit is oil filled.
- Side load angle must stay below 2°. -SP variants tolerate up to 30°.
- Never use the buffer as an end stop — fit a stop collar 1 mm before end of travel and never remove the steel strike head.
- Parallel buffers must be the same model, with the knob on the same step.
- Do not paint the piston rod, and do not paint over the body — it needs to shed heat.
- Inspect monthly in frequent service, every 6 months on safety and emergency duty.
Send Us Five Numbers — Get a Sizing Report in 48 Hours
Every BD unit is configured against your application data. Give us these five values and our engineers will return a recommended model with verified shock-force versus stroke and deceleration versus stroke curves. Free, and with no commitment to buy.
- W kg · moving weight
- V m/s · impact velocity
- Fp N · driving force
- n pcs · buffers in parallel
- Cycles / hour
BD Series FAQ
Part of a Complete Crane Rail System
Hydraulic buffers are one component we supply. The same engineering and manufacturing team also delivers the rest of the runway system:
- Crane rails — rail sections for crane runway systems
- Rail clips — bolted and welded fastening systems
- Rail pads — vibration and impact damping
- Sole plates — rail support and load distribution
- Rail grouts — cementitious bedding for rail fixings
- Custom machining — molds and precision machined parts
Talk to an Engineer
Tell us your application and we will come back with a recommendation, a sizing calculation and a quotation. If you are still at the design stage, we are happy to work from drawings.
