Medical Equipment
Counterbalance, controlled motion, and hold-open safety for adjustable beds, examination couches, patient lifts, dental chairs, and equipment enclosures — built for OEM integration and long-term aftermarket supply.
- 1 The Part Nobody Notices Until It Drifts
- 2 Four Places Gas Springs Do the Work in Medical Devices
- 3 One Spring or Two: Sizing for Patient-Bearing Loads
- 4 When to Specify Stainless Steel or Locking Gas Springs
- 5 Specifying Gas Springs for Medical Equipment
- 6 Force Calculation and Mounting
- 7 Why Medical OEMs Source Gas Springs for Medical Equipment from Newtone
- 8 Frequently Asked Questions
- 9 Conclusion
- 10 Get a Specification or Quote
The Part Nobody Notices Until It Drifts
A nurse raises a bed backrest with one hand while steadying a patient with the other. A clinician sets an examination couch to a working angle and expects it to stay there. A technician lifts a heavy sterilizer lid and needs it to hold open, not guillotine shut. Gas springs for medical equipment do all of this quietly — until the force is wrong, and then the section is heavy to lift, creeps under load, or drops. On equipment that handles patients, that is a safety problem, not a comfort one.
Newtone is a gas spring manufacturer based in Turkey, exporting to more than 60 countries, with over two decades supplying OEM and replacement units to equipment builders. This guide is for the people who actually specify these parts: OEM design engineers selecting force, stroke, and hold type; procurement managers sourcing matched replacements; and distributors looking for a manufacturer that holds tolerance batch after batch.
Who this page is for: OEM engineers integrating lift support into a new device, procurement managers sourcing service-network replacements, and distributors evaluating a manufacturing partner for consistent, traceable supply.
Four Places Gas Springs Do the Work in Medical Devices
Each role carries a different load, swings through a different arc, and meets a different cleaning regime. Treating them as one generic “lift support” is the fastest way to ship a spring that is wrong for half the units it lands on.
Adjustable Bed & Couch Sections
Backrests and leg sections on hospital beds and examination couches. The spring counterbalances the panel plus a fraction of the patient load through a wide arc, so the required force changes sharply with angle — the worst case is near closed, not when the section is already raised.
Patient Lifts & Transfer Aids
Hoist booms and sit-to-stand mechanisms carry the highest forces and the highest stakes. A drifting or unbalanced boom under a suspended patient is unacceptable, so force matching and a generous fatigue margin matter here above all.
Dental & Treatment Chairs
Backrests and headrests a clinician sets and leaves for the length of a procedure. These are the classic case for rigid-lock springs, holding the section precisely where it is positioned, with smooth damped motion so nothing jolts the patient.
Enclosures, Sterilizer Lids & Service Panels
Autoclave lids, analyzer covers, and maintenance hatches that must stay open hands-free during loading or service. Lower patient risk, but hold-open safety and disinfectant-resistant surfaces still drive the specification.
One Spring or Two: Sizing for Patient-Bearing Loads
A gas spring’s output follows F = p × A — internal gas pressure p acting on the rod cross-section A = πd²/4. Doubling the rod diameter quadruples the force at the same pressure, which is why patient-bearing sections often run two slimmer springs instead of one oversized unit that no longer fits the mounting envelope.
⬤ Single Spring Setup
- Supported load under ~10 kg (22 lb)
- Narrow, centered section, no lateral flex
- Headrests, light covers, access panels
- Adequate moment arm at the hinge
- Simpler installation, lower cost
⬤ Paired Spring Setup
- Backrests, lift booms, wide decks
- Patient-bearing or offset-hinge sections
- Loads above ~10 kg (22 lb)
- Even load distribution, reduced twist
- Springs force-matched to ±5%, same batch
When to Specify Stainless Steel or Locking Gas Springs
Standard units handle most enclosed mechanisms reliably. Two scenarios on medical equipment justify an upgraded specification, and both are easy to spot at the design stage.
Stainless Steel for Cleaned and Sterile Surfaces
Hospital equipment is wiped down many times a day with alcohols, quaternary ammonium compounds, and chlorine solutions, and some surfaces face full washdown. Any spring exposed to that regime should use a 316L body and rod, which resists the pitting that eventually lets cleaning fluid reach the seals. For these positions, stainless steel gas springs are worth specifying as standard. For fully enclosed internal mechanisms, a black nitrided rod (900–1000 HV, 20–30 µm) with HNBR seals is sufficient at lower cost.
Locking and Rigid-Lock for Held Positions
Where a section must stay put under load, a locking gas spring adds a mechanical hold. End-lock units hold at full extension for hold-open safety on sterilizer lids and service hatches; rigid-lock (lock-anywhere) units hold at any point along the stroke for precise patient positioning on couches and chairs. The release method depends on the device, so confirm the locking type against the load and the operator’s reach at the design stage rather than late in qualification.
Specifying Gas Springs for Medical Equipment
| Section / Device | Supported Weight | Recommended Force | Spring Count | Notes |
|---|---|---|---|---|
| Dental / chair headrest | 2–6 kg (4–13 lb) | 80–200 N (18–45 lbf) | 1 | Rigid-lock for set positioning |
| Examination couch backrest | 4–10 kg (9–22 lb) | 150–400 N (34–90 lbf) | 1–2 | Check moment arm near closed |
| Hospital bed backrest | 12–25 kg (26–55 lb) | 300–600 N each (67–135 lbf) | 2 | Paired — request matched batch |
| Patient lift / hoist boom | 20–40 kg (44–88 lb) | 600–1300 N each (135–292 lbf) | 1–2 | High fatigue margin; force-matched |
| Sterilizer lid / service panel | 3–10 kg (7–22 lb) | 100–300 N (22–67 lbf) | 1–2 | Locking version for hold-open |
| Wipe-down / sterile area | Any | Per above | Per above | Stainless steel recommended |
Force Calculation and Mounting
The forces above are starting points. The final value comes from a moment balance about the hinge, because a section’s required force is driven as much by geometry as by weight.
- F — required force per spring, N (lbf)
- W — supported weight = m × g, N — panel plus patient load fraction
- Lg — hinge to combined center of gravity, mm (in)
- φ — load-arm angle above horizontal at the position checked
- r — spring perpendicular moment arm, mm (in)
- n — number of springs
Worked example. A couch backrest supports m = 20 kg (44 lb) at the near-horizontal worst case, so W = 20 × 9.81 = 196 N (44 lbf) and cos φ ≈ 1. With Lg = 350 mm (14 in) and a spring moment arm r = 60 mm (2.4 in), the total demand is 196 × 350 ÷ 60 ≈ 1144 N, or two matched springs of roughly 575 N (129 lbf) each. Two corrections then follow: gas spring force changes about 0.3% per °C, so size at the equipment’s operating temperature, and extension force runs above compression force (progression ratio typically 1.2–1.6), which is what gives the smooth, damped close.
Mounting matters as much as force. Fit the spring with the rod pointing down in the closed position so oil keeps the seals lubricated and damping stays quiet. Keep both pivots in the same plane of motion — gas springs take axial load only, and side load shortens life. The lower pivot’s position relative to the hinge changes the effective moment arm more than the force value does, so adjust geometry first. Share your dimensions and our team will run this against the full standard gas spring range and confirm the right mounting bracket.
Why Medical OEMs Source Gas Springs for Medical Equipment from Newtone
We are a manufacturer, not a distributor. Every spring is built in our own facility in Turkey, so tolerance, material sourcing, and lead time stay under our control rather than a third party’s.
Frequently Asked Questions
Use a moment balance about the hinge: F = (W × Lg × cos φ) ÷ (n × r). Multiply the supported weight by the horizontal distance from the hinge to the center of gravity, then divide by the spring’s moment arm at the worst-case angle, usually near closed. For a 20 kg (44 lb) supported load at a 350 mm (14 in) arm with a 60 mm (2.4 in) spring moment arm, two matched springs of about 575 N (129 lbf) each will balance it. Share your geometry and Newtone will run the calculation.
Mount it with the rod pointing down in the closed or rest position so the oil keeps the seals lubricated and damping stays quiet and consistent. Keep both pivots in the same plane of motion to avoid side load, which shortens life, and use an end fitting that allows slight angular misalignment. The lower pivot’s position relative to the hinge affects open and close behavior more than the force value does.
Specify 316L stainless steel when the spring faces frequent disinfectant wipe-down, washdown cleaning, or high-humidity sterile areas. For enclosed internal mechanisms not exposed to cleaning agents, a black nitrided rod with HNBR seals provides sufficient corrosion protection at lower cost.
A standard gas spring lifts and damps but holds no fixed point. An end-locking spring holds at full extension for hold-open safety on service panels and access hatches. A rigid-lock (lock-anywhere) spring holds at any point along the stroke, which suits examination couches and positioning tables where the section must stay exactly where it is set.
Yes. We supply gas springs for new equipment integration and for service or aftermarket replacement, often from the same configuration, so replacement parts match the original force and stroke. Batch traceability and engineering support are available.
Conclusion
On medical equipment, a gas spring is invisible when it is right and a liability when it is wrong. The difference is rarely complicated: a force value derived from a real moment balance rather than panel weight alone, a seal and rod specification matched to the cleaning environment, and a manufacturing tolerance tight enough to keep paired springs balanced under a real load.
Newtone has been solving exactly this for medical OEMs and distributors for over two decades. Whether you are designing a new bed, couch, lift, or chair, replacing a failed spring in a fielded device, or qualifying a supplier for production, we bring the engineering support around the part as well as the part itself.
Send us your section weight, hinge geometry, and stroke. We will return a force recommendation, a datasheet, and a quote — typically within 5 business hours.
Get a Specification or Quote
Tell us the device type, supported weight, and mounting geometry. Our team handles the force calculation, sample datasheet, and competitive pricing.
