Torque Hinges: Constant, Adjustable and Positioning Types
Hold doors, lids and panels at any angle without gas struts or prop rods — for enclosures, medical equipment, control panels and vehicle compartments.
A torque hinge is a positioning hinge that holds a door, lid or panel at any angle through its full range of motion. Inside the hinge body, friction elements generate a controlled resistance torque, so the panel stays exactly where the operator leaves it — no gas struts, no prop rods, no separate stays.
That sounds like a small thing until you count what it removes from a design: no gas strut to source and mount, no prop rod to lose, no bracket welded to the cabinet, and no slammed fingers when a heavy lid drops. Torque hinges are the standard answer on enclosure display doors, medical equipment arms, industrial control panels and vehicle compartments wherever a panel must hold position under vibration.
How a Torque Hinge Works
A constant torque hinge uses internal friction elements — disc or sleeve packs preloaded by a spring — to produce a resistance torque that is essentially the same at every angle of travel. The operator moves the panel with slightly more than that torque; release it, and it holds. Because the holding force comes from calibrated internal friction rather than a simple pin gripping a leaf, the torque stays stable over the service life instead of fading as surfaces wear.
Three points of confusion are worth clearing up:
Torque hinges vs. spring hinges
A spring hinge is built to close the door — it stores energy and returns the panel to closed. A torque hinge resists motion in both directions so the panel stays put. Need automatic closing? Choose a spring hinge or door closer. Need the panel to hold open at any angle? Choose a torque hinge.
Torque hinges vs. soft-close (damping) hinges
A damping hinge slows the final few degrees of closing so the door lands quietly. It does not hold position. Torque hinges position; damping hinges decelerate. Some designs combine both, but they are different functions.
Torque hinges vs. basic friction hinges
A basic friction hinge holds by squeezing the pin, and its holding force drifts as the joint wears. A torque hinge packages the friction between dedicated elements that are cycle-tested, so holding torque stays stable over the rated service life.
Three Families of Torque Hinges
Constant Torque Hinges
One factory-set torque value for the life of the hinge — set it and forget it. For panels of known, fixed weight where the design will not change in the field.
- SL-H1-3428-54 / SL-H1-3427-40: aluminum alloy, anodized silver or black, flush-mount bodies for minimal installation space.
- SL-H1-3426-30: zinc alloy for light-duty lids, internal threads for a clean exterior.
- SL-H1-3423-601-30: heavy-duty 60×60 mm zinc leaf with M6 stud and nut fixing — holds position under vibration.
Adjustable Torque Hinges
An adjustment screw sets the preload on the internal friction elements. Tune once at assembly to match the actual door weight — the right choice when panel weight varies or may change in the field.
- SL-H1-3405-01: glass-fiber reinforced PA66, symmetrical design for exposed mounting.
- SL-H1-3405-02: the same adjustable platform in an alternate frame size, simplifying the bill of materials.
Positioning (Detent) Hinges
Resistance torque plus a positive mechanical detent at a specific angle: the panel clicks into a firm hold and releases with a deliberate push. Where a constant torque hinge holds anywhere, a detent hinge holds firmly at one designed angle.
- SL-H1-3401-15011-60: 150° hold-open detent, stainless steel fixed tube, corrosion-resistant POM leaves — made for service positions where a door must lock open.
How to Choose a Torque Hinge
Sizing a torque hinge is a short calculation, not a guess:
- Weigh the panel and find its balance point. Torque demand is greatest when the panel is horizontal (90° open), where the full weight acts at maximum lever arm: T = W × L, with W the panel weight and L the distance from the hinge axis to the center of gravity.
- Apply a safety factor. Multiply by 1.5 for indoor, low-vibration equipment and up to 2.0 for industrial or outdoor installations that see vibration, temperature swing and long service lives.
- Decide constant or adjustable. Fixed, known panel weight → constant torque. Mixed or changing loads → adjustable torque.
- Check the environment. Aluminum and zinc alloy bodies with anodized or plated finishes suit industrial cabinets; POM leaves with stainless steel tubes add corrosion resistance for damp or washdown-adjacent positions.
- Confirm fit and fixing. Stud-and-nut, screw mount or internal thread — pick the fixing that matches your door construction, and confirm torque values and installation dimensions against the drawing for your model.
Removable and Lift-Off Hinges
Sometimes the requirement is not holding position — it is getting the door off the cabinet fast. Lift-off hinges (also called removable pin hinges or detachable hinges) let the door lift straight off its hinges without tools, so technicians can service the enclosure interior without supporting a heavy door or removing hardware. Corner-door versions seat into the folded corner of formed sheet-metal doors for a flush, cost-effective installation, and most open a full 180°.
SL-H2-3303-2017-A1
Compact stainless steel corner door hinge that snaps into the folded corner of 2 mm formed sheet-metal doors — fast installation, full 180° opening, and the leaf releases to lift the door off.
SL-H2-3308-112CF-A1
Heavy-duty right-hand corner door hinge in polished zinc alloy with screw-and-nut fixing, built for larger formed doors in frequent-open service; full 180° rotation and tool-free door removal.
SL-H2-3315-40
Powder-coated zinc die-cast corner door hinge, snap-in plus bolt-and-nut fixing — a compact, economical way to hinge corner doors with 180° opening and lift-off capability.
For doors that stay put but need a clean pivot, our surface-mount and embedded corner hinges cover the rest of the range — stainless steel and zinc alloy, screw-mounted or snap-in, matched to standard and 8PT cabinet frame systems.
Where Torque Hinges Are Used
Electrical enclosures
Display and access doors that must hold open while both hands are on the work.
Electrical enclosure applications →Medical equipment
Monitor arms, equipment lids and positioning panels that must move smoothly and hold without drift.
Medical equipment applications →Industrial control panels
Heavy access doors held open under vibration, no prop hardware.
Industrial equipment applications →Vehicle and RV compartments
Overhead lockers and service hatches that must never drop on the operator.
RV applications →All Hinge Models at a Glance
| Model | Family | Material | Finish | Mounting | Notes |
|---|---|---|---|---|---|
| SL-H1-3428-54 | Constant torque | Aluminum alloy | Anodized silver | Screw mount | Flush-mount body |
| SL-H1-3427-40 | Constant torque | Aluminum alloy | Anodized black | Screw mount | Flush-mount body |
| SL-H1-3426-30 | Constant torque | Zinc alloy | Chrome plated | Internal thread | Light duty |
| SL-H1-3423-601-30 | Constant torque | Zinc alloy | Chrome plated | M6 stud & nut | Heavy duty, 60×60 mm leaf |
| SL-H1-3405-01 | Adjustable torque | PA66+30%GF | — | Screw mount | Symmetrical, exposed mount |
| SL-H1-3405-02 | Adjustable torque | PA66+30%GF | — | Screw mount | Alternate frame size |
| SL-H1-3401-15011-60 | Detent positioning | POM + stainless tube | — | Bolt and nut | 150° hold-open |
| SL-H1-3101-5630-A1 | Surface free-swing | Stainless steel | Mirror polished | M6 countersunk screw | 50×63 mm, easy-clean |
| SL-H1-3204-1910-A1 | Surface free-swing | Stainless steel | Brushed | Screw mount | No cutouts needed |
| SL-H1-3204-1300-A1 | Surface free-swing | Stainless steel | Brushed | Screw mount | No cutouts needed |
| SL-H2-3303-2017-A1 | Corner removable | Stainless steel | Brushed & polished | Snap-in | Heavy duty, lift-off |
| SL-H2-3308-112CF-A1 | Corner detachable | Zinc alloy | Brushed & polished | Screw + nut | Heavy duty, tool-free removal |
| SL-H2-3315-40 | Corner removable | Zinc alloy | Powder coated | Snap-in + bolt & nut | Light duty, lift-off |
| SL-H1-3231-30 | Corner embedded | Stainless steel | Polished | Embedded mount | 65 mm leaf, 180° |
| SL-H2-3316-40 | 8PT corner | Zinc alloy + steel | Powder coated | Internal thread + screw | Matches 8PT frames |
Torque values and installation dimensions are confirmed per drawing for each model.
Frequently Asked Questions
What is a torque hinge?
A torque hinge is a hinge with built-in resistance that holds a door, lid or panel at any angle without gas struts, prop rods or stays. Internal friction elements generate the holding torque, so the panel stays where the operator leaves it and moves again only when pushed.
Constant torque vs adjustable torque hinge: which one do I need?
Choose constant torque when the panel weight is fixed and known — you get one factory-set value with nothing to adjust. Choose adjustable torque when panel weight varies across your product range or may change in the field; a single adjustment screw tunes the hinge at assembly.
What is a detent hinge?
A detent hinge (also called a positioning hinge) is a torque hinge with a positive mechanical click at a designed angle. Instead of holding anywhere in the range, it rotates freely and then locks firmly at the detent — for example 150° — releasing only with a deliberate push. Use one when the panel must lock open for servicing.
How much torque does my hinge need?
Calculate the worst case: torque demand peaks when the panel is horizontal, at T = W × L (panel weight × distance from hinge axis to center of gravity). Multiply by a safety factor of 1.5 indoors and up to 2.0 for vibration or outdoor service, then size the hinge to meet or slightly exceed that value. Our team confirms torque values per drawing for each model.
What is a lift-off hinge and when do I need one?
A lift-off hinge lets the door lift straight off without tools, so it can be removed for servicing without detaching hardware. Choose one wherever doors must come off frequently for maintenance, or where the cabinet interior needs full, unobstructed access.
Related Selection Guides
Get the Right Hinge for Your Panel
Send us your door drawings or the panel weight, dimensions and opening angle, and our engineers will recommend the torque hinge, detent hinge or lift-off hinge that fits — with torque values and installation dimensions confirmed against the production drawing. MOQ from 100 pcs; details on request.