| Type | Diagram Characteristic | Security Level | |------|------------------------|----------------| | | Curved metal hook rotating into keep | High (anti-jemmy) | | Roller cam | Cylindrical roller sliding into wedge keep | Medium | | Deadbolt + hooks | Central bolt + top/bottom hooks | Very high | | Mushroom head cams | Rounded pins that self-lock when forced | Highest (anti-snap) |
+----------------------------------------+ | [ Top Extension Strip ] | <-- Long metal strip (Faceplate) | | | | [Top Hook/Bolt] | <-- Upper locking point | | | | | | | +--------------+ | | | Latch | | <-- Keeps door shut when unlocked | | (Reversible)| | | +--------------+ | | | | | | [Handle]====| ( ) Spindle | | <-- Drives the latch and gearbox | | | | | | [ GEARBOX ] | | <-- Core command unit (Center case) | | | | | | (8) Euro | | <-- Cylinder lock entry point | | Cylinder| | | +--------------+ | | | Deadbolt | | <-- Primary central locking bolt | +--------------+ | | | | | | | | [Bottom Hook/Bolt] | <-- Lower locking point | | | | [ Bottom Extension Strip ] | +----------------------------------------+ 1. Central Gearbox (Center Case)
⭐⭐⭐⭐☆ (4.5/5) – Minus 0.5 because without physical access to the door, diagrams alone can be confusing due to brand variations. upvc door locking mechanism diagram
The spring-loaded part that holds the door shut without being locked; it retracts when you push the handle. Critical Measurements for Replacement
These engage with "keeps" on the door frame to provide security and weather sealing. They typically include: | Type | Diagram Characteristic | Security Level
Here is a detailed explanation of the parts labeled in the diagram above.
| Component | Function | |-----------|----------| | | Central unit that translates handle/key movement to rods | | Euro cylinder (key cylinder) | Key-operated cam that retracts or extends the main lock | | Handle spindle | Square bar connecting handles to gearbox | | Top & bottom drive rods | Metal strips transmitting motion to locking points | | Roller cams / hooks / deadbolts | Actual locking elements that engage with the frame | | Strike plates (keeps) | Metal plates on frame where cams/hooks insert | | Snib (lock button) | Small button on handle to lock handle without key (inside only) | They typically include: Here is a detailed explanation
| Symptom | Likely Culprit | Diagram Part | | :--- | :--- | :--- | | | Broken drive in the gearbox. The internal gears have stripped. | (C) Gearbox | | Handle is floppy/loose | Broken spring cassette. The mechanism that returns the handle to level is snapped. | (C) Gearbox | | Key turns but doesn't lock | The cam on your key cylinder is worn, OR the receiver in the gearbox is stripped. | (E) Cylinder or (C) Gearbox | | Door sticks/won't close | Misalignment. The hooks/rollers are hitting the frame edge instead of sliding in. | (B/F) Locking Points or Frame alignment | | Locking points don't move | The connection between the gearbox and the extension strips has failed. | (A/G) Extensions |