Detent Hinge Angle & Release Torque Specification Guide

Two supplier drawings can both say 90° detent and still describe different products. One may define 90° as the center of a controlled engagement window. The other may only indicate that the panel feels a click somewhere near 90°. Neither statement tells you how far the assembled panel may vary, how much torque is required to leave the position, or whether the result changes when the panel approaches from the opposite direction.

A usable detent hinge specification must separate angle, angular tolerance, engagement behavior, holding resistance, release torque, direction, and test conditions. Those fields turn a catalog description into a requirement that different suppliers can quote and test against.

This guide starts after the positioning method has already been selected. Use the detent hinge vs torque hinge guide first when the project still needs to decide between indexed positions, free-stop holding, or a hybrid mechanism.

A “90° Detent” Is Incomplete

The number alone does not define the mechanism’s behavior. Before a supplier can compare an existing model or review a custom request, the drawing must answer several different questions.

Specification Field	What It Must Define	What Goes Wrong When It Is Missing
Reference datum	The zero-angle geometry used for every stated position	Supplier and OEM measure the same position from different surfaces
Nominal detent angle	The intended center or target position	A catalog angle is assumed to equal the final panel angle
Engagement window	The angular region in which the mechanism enters or captures the detent	The panel feels vague, engages late, or settles farther than expected
Angular tolerance	Allowed variation for the hinge or complete assembly	Two samples both “pass” while their usable positions visibly differ
Approach direction	Whether the position is reached while opening, closing, or both	Backlash or cam geometry creates different stopping angles
Release torque	The peak torque required to initiate motion out of the engaged position	User effort is unknown or suppliers report incompatible values
Holding condition	The external moment the engaged mechanism must resist	A noticeable click is mistaken for adequate load capacity
End-stop function	Whether another structure absorbs maximum-opening impact	The detent is overloaded as a structural stop

These fields describe different jobs. A detent can locate a panel without carrying a large external moment. It can also resist a useful load yet have a release peak that is uncomfortable for the operator. Treating every function as one “detent strength” value hides those differences.

Detent hinge product photo in black and white finishes

Define the Angle From One Datum

Start with the physical geometry, not with the supplier’s catalog label. The drawing should show the hinge axis, the fixed reference surface, the moving reference surface, and the direction of positive rotation. A closed panel is often used as 0°, but that only works when “closed” is repeatable and not controlled by a compressible gasket, an adjustable latch, or flexible sheet metal.

Use a stable reference. Mounting-leaf planes, bracket datums, or defined panel surfaces are usually clearer than a visual door position.
Show the viewing side. Clockwise and counterclockwise descriptions become ambiguous when the observer changes sides.
State whether the angle is hinge-level or assembly-level. Bracket offset and panel geometry can make the final panel angle different from the internal detent angle.
Do not use the detent angle as a substitute for maximum travel. The motion system may need a separate overtravel allowance and structural stop.

Detent hinge angle datum with engagement window and mechanical stop

Drawing rule: If the supplier cannot identify the same 0° datum and positive rotation direction that appear on the equipment drawing, the quoted detent angle is not yet comparable.

Nominal Angle, Window, and Tolerance

Three angle values are often blended together even though they describe different behavior.

Nominal Position

The nominal angle is the intended indexed position, such as θ₁. It should be tied to the drawing datum. State whether θ₁ is the theoretical center of the detent geometry, the measured panel position after engagement, or the supplier’s catalog designation.

Engagement Window

The engagement window is the region in which the mechanism begins to enter, capture, or settle into the indexed position. A wide window can make the panel easy to locate but less crisp. A narrow window can provide a precise feel yet become sensitive to mounting error, frame twist, and multi-hinge mismatch.

Angular Tolerance and Repeatability

Angular tolerance defines allowable variation between parts or assemblies. Repeatability describes how closely the same sample returns to the position over repeated operations. They are not interchangeable. A hinge may repeat well at an angle that is consistently offset from the drawing target, while a production lot may average correctly but show excessive unit-to-unit spread.

When the final panel position matters, specify acceptance at the assembly level as well as at the hinge level. Sheet-metal deflection, bracket compliance, fastener clearance, and gasket force can move the panel even when the hinge mechanism is consistent.

Release Torque, Not an Unlocated Force

Release torque is the peak rotational moment required to start moving the hinge out of an engaged detent under defined conditions. It is usually the most transferable way to describe release behavior because it is referenced to the hinge axis.

A force value can still be useful for ergonomics, but the force location must be stated. The same hinge can feel light at the edge of a large panel and heavy when the operator pushes close to the axis.

Preliminary relationship: hand force ≈ release torque ÷ perpendicular distance from the hinge axis. The complete assembly may require more or less force because gravity, seals, cables, friction, and the direction of motion add their own moments.

A supplier value should identify whether it represents the maximum peak, an average over several samples, or a limit. It should also state the angular region used to search for the peak. One test system may capture a narrow spike; another may smooth it through filtering or coarse sampling. The numbers can differ even when the physical hinge is the same.

For fixture design, speed control, torque-angle recording, and data treatment, refer to the guide on ヒンジのトルクの測定方法. This page uses those methods only to define what the detent release result must report.

Detent hinge torque-angle curve showing holding region and release peak

Holding at the Detent

A positive click does not prove that the hinge can support the required panel load. The engaged mechanism must resist the external moment created by gravity, acceleration, cable pull, seal force, user contact, or another project-specific load.

要件	Question for the Supplier	Assembly Check
Static holding	What torque can the fully engaged detent resist without leaving the position?	Apply the actual panel moment in the installed orientation
Release threshold	What peak torque initiates movement in each direction?	Measure operator effort at the intended hand location
Drift or backlash	How much angular movement is allowed while the detent remains engaged?	Check visible panel movement and functional clearance
Transient load	Is impact, vibration, or transport load included in the rating?	Do not infer dynamic capacity from a static release value
End-of-travel load	Is the detent rated to absorb repeated maximum-opening impact?	Use a separate structural stop unless the function is explicitly rated

Holding and release may be related by the same cam or spring geometry, but they should not be assumed to be identical. Test direction, dwell, preload, and the definition of “movement” can change the reported threshold. Ask for both functions when both matter.

Direction Changes the Result

A detent can behave differently when approached from opening and closing directions. Internal cam geometry, spring preload, friction, gravity, and assembly load can produce different entry and release peaks. The specification should not use one value for both directions unless the test data supports that choice.

State the approach direction for every detent angle.
Record entry and release separately when the mechanism has a noticeable capture or breakout peak.
Define test speed because lubricant response and dynamic effects can change the measured peak.
Define dwell time before release when the panel will remain parked at the detent during use.
State temperature and preconditioning when the mechanism contains lubricated, polymer, spring, or friction elements.
Identify the fixture and orientation so gravity and mounting compliance are not mixed into a hinge-only value without explanation.

The supplier report should show a torque-angle trace or enough raw results to identify where the release value occurred. A single unlabeled number cannot show whether it came from opening, closing, a fresh sample, a precycled sample, or the complete panel.

Two Hinges Must Engage Together

A paired assembly creates a second specification problem: timing. If one detent engages before the other, the panel can rack, twist the mounting brackets, or feel as though it has two clicks. Increasing the release torque does not correct that mismatch.

Why two “90°” hinges can still bind: Supplier A defines the detent center from the closed mounting-leaf planes and controls its angular tolerance. Supplier B marks 90° as a nominal catalog position without stating the datum or window. Both parts fit the same mounting holes. In the assembled panel, one side begins to engage before the other, so the frame twists and the operator feels a hard second click. The issue is synchronization, not nominal angle alone.

This is an illustrative engineering scenario, not a customer project record or product test claim.

For two active detent hinges, control the common axis, mounting datums, individual angle tolerance, pair-to-pair timing, and frame stiffness. Another architecture is one active detent hinge plus a follower hinge, but the active unit and brackets must then carry the required positioning load. The correct arrangement depends on the panel structure and available supplier data.

Two detent hinges showing out-of-sync and synchronized engagement

Test the Complete Panel

A bench fixture can verify the hinge mechanism. It cannot reproduce every force in the machine. The final sample should be installed with production-intent brackets, fasteners, cables, seals, panel mass, center of gravity, and any structural stop.

The drawing may fit. The panel can still miss the intended position.

Assembly Observation	Possible Cause	What to Recheck
Panel engages at different angles from opposite directions	Backlash, direction-sensitive cam behavior, or bracket compliance	Opening and closing traces; datum; assembly stiffness
Release feels much heavier than the hinge report	Short hand lever, gravity, seal compression, cable force, or axis error	Actual hand point and complete moment balance
Position is correct unloaded but shifts with the panel installed	External moment or structure deflection	Panel CG, bracket stiffness, and engaged holding requirement
Two clicks occur near one position	Paired hinges engage at different times	Angle tolerance, common axis, frame twist, and hinge matching
Detent changes after repeated use	Wear, preload shift, mounting movement, or lubricant change	Post-cycle angle, release torque, and fastener condition

Sample approval should record the accepted drawing revision, hinge identification, test direction, angle result, release result, panel configuration, and any post-cycle change required by the project. Do not approve production from one hand-operated sample with no recorded acceptance limits.

Write the Supplier Specification

The RFQ should be short enough to use and complete enough to compare. The following structure keeps the requirement focused on detent behavior rather than generic purchasing stages.

DETENT HINGE FUNCTION
- Application and moving-panel description:
- Hinge quantity and arrangement:
- Required detent positions:
- Behavior required between positions:
- Separate structural stop: Yes / No / Supplier-rated detent stop

ANGLE DEFINITION
- Zero-angle datum:
- Positive rotation direction and viewing side:
- Nominal detent angle(s):
- Engagement window for each position:
- Hinge-level angular tolerance:
- Complete-assembly angular tolerance:
- Approach direction: Opening / Closing / Both
- Allowed backlash or movement while engaged:

TORQUE AND LOAD
- Release torque limit in each direction:
- Test angle region used to identify the release peak:
- Required holding condition at each detent:
- External panel moment or load case:
- User hand location, if operating force matters:
- Entry or capture behavior requirement:
- Baseline resistance between detents, if required:

TEST CONDITIONS
- Test orientation and fixture:
- Rotation speed:
- Dwell before release:
- Temperature:
- Preconditioning cycles:
- Sample quantity:
- Data reporting method:
- Initial and post-cycle acceptance, if required:

DRAWING AND TRACEABILITY
- Supplier part number and revision:
- Material and finish:
- Mounting dimensions and datums:
- Left/right or directional version:
- Sample or lot identification:
- Required report or curve:

Use the guide to reading a ヒンジの仕様書および設計図面 when the project also needs a broader review of dimensions, revisions, tolerances, and drawing ownership.

Send a Detent Requirement for Review

Send the assembly drawing, angle datum, required indexed positions, approach direction, acceptable release torque, panel load, hinge quantity, operating environment, and expected cycles. HSP can use those inputs to identify missing specification fields and compare them with available 止め金付きヒンジのモデル.

Send Your Detent Drawing

Detent Hinge Specification Questions

Is the detent angle the same as the maximum opening angle?

Not automatically. A detent angle is an indexed position. Maximum opening may include additional travel and should normally be controlled by a separate structural stop unless the supplier specifically rates the detent mechanism for repeated stop loads.

Should detent release torque and holding torque be the same value?

Do not assume they are the same. Release torque is the peak needed to initiate motion out of the detent under defined conditions. Holding describes the external moment the engaged mechanism can resist. Direction, dwell, test method, and movement criteria can make the reported values different.

Can I specify release force instead of release torque?

Yes, but the force application point, direction, panel geometry, and distance from the hinge axis must be defined. Torque is usually easier to compare between suppliers, while force is useful for checking operator effort on the complete panel.

Why can two detent hinges engage at different times?

Their individual detent angles, angular tolerances, mounting datums, hinge axes, or frame stiffness may not match closely enough. One hinge can begin engagement first and twist the panel before the second hinge reaches its detent.

What data should a supplier return for a detent hinge review?

Request the drawing revision, angle datum, nominal detent angle, engagement window, angular tolerance, approach direction, release torque in each direction, holding condition, between-position behavior, test speed, dwell, temperature, sample quantity, torque-angle evidence, and sample identification.