LRU Hold-Down Latches and Front Locking Devices
LRU Hold-Down and Quick-Release Latches for Rack-Mounted Avionics
Front locking devices hold an LRU, chassis or module unit in its mounting rack and release it without tools. Twenty catalogue part numbers across QSJ-A, QSJ-B, the B-class lever latch and the CLA43 fixed device, with the installation length and hole spacing published for each clamp.
LRU Hold-Down Latches and Front Locking Devices
LRU Hold-Down and Quick-Release Latches for Rack-Mounted Avionics
Front locking devices hold an LRU, chassis or module unit in its mounting rack and release it without tools. Twenty catalogue part numbers across QSJ-A, QSJ-B, the B-class lever latch and the CLA43 fixed device, with the installation length and hole spacing published for each clamp.
Front Locking Device Part Numbers
Every dimension below is taken from the 2025 product manual. Filter by configuration, then confirm the drawing before release to production. A dash means the value is not published for that variant in the manual; ask us and we will confirm it on the drawing.
| Model | Type | L (mm) | X1 (mm) | X2 (mm) | Weight (g) | Mounting hole | Material | Finish | Drawing |
|---|---|---|---|---|---|---|---|---|---|
| CLA43-2W-H1-S3 | CLA43 | — | — | — | — | — | — | — | Drawing |
| QSJ-A45 | A type | 45 | — | — | 48 g | — | Stainless steel | Passivation | Drawing |
| QSJ-A48 | A type | 48 | — | — | 50 g | — | Stainless steel | Passivation | Drawing |
| QSJ-A55 | A type | 55 | — | — | 52 g | — | Stainless steel | Passivation | Drawing |
| QSJ-A70 | A type | 70 | — | — | 75 g | — | Stainless steel | Passivation | Drawing |
| QSJ-B-1 | B-clamp | 111.1 | 95 | 137 | 123 g | M5×0.8 | Aluminium alloy, stainless steel | Hard anodize, sand blast | Drawing |
| QSJ-B-2 | B-clamp | 76.2 | 60 | 102 | 102.5 g | M5×0.8 | Aluminium alloy, stainless steel | Hard anodize, sand blast | Drawing |
| QSJ-B-3 | B-clamp | 98.5 | 82.4 | 124.4 | 117.6 g | M5×0.8 | Aluminium alloy, stainless steel | Hard anodize, sand blast | Drawing |
| QSJ-B2-1 | B2-clamp | 111.1 | 95 | 137 | 80 g | M5×0.5 | Aluminium alloy, stainless steel | Hard anodize, sand blast | Drawing |
| QSJ-B2-2 | B2-clamp | 76.2 | 60 | 102 | 70 g | M5×0.5 | Aluminium alloy, stainless steel | Hard anodize, sand blast | Drawing |
| QSJ-B2-2A | B2-clamp | 76.2 | 60 | 102 | 70 g | M4×0.7 | Aluminium alloy, stainless steel | Hard anodize, sand blast | Drawing |
| QSJ-B2-3 | B2-clamp | 98.5 | 82.4 | 124.4 | 75 g | M5×0.5 | Aluminium alloy, stainless steel | Hard anodize, sand blast | Drawing |
| QSJ-B3-1 | B3-clamp | 111.1 | 95 | 137 | 98 g | M5×0.5 | Aluminium alloy, titanium alloy | Hard anodize, sand blast | Drawing |
| QSJ-B3-2 | B3-clamp | 76.2 | 60 | 102 | 80 g | M5×0.5 | Aluminium alloy, titanium alloy | Hard anodize, sand blast | Drawing |
| QSJ-B3-2A | B3-clamp | 76.2 | 60 | 102 | 80 g | M4×0.7 | Aluminium alloy, titanium alloy | Hard anodize, sand blast | Drawing |
| QSJ-B3-3 | B3-clamp | 98.5 | 82.4 | 124.4 | 90 g | M5×0.5 | Aluminium alloy, titanium alloy | Hard anodize, sand blast | Drawing |
| QSJ-B45 | B type | 45 | — | — | 71 g | — | Stainless steel | Passivation | Drawing |
| QSJ-B48 | B type | 48 | — | — | 73 g | — | Stainless steel | Passivation | Drawing |
| QSJ-B55 | B type | 55 | — | — | 75 g | — | Stainless steel | Passivation | Drawing |
| QSJ-B70 | B type | 70 | — | — | 98 g | — | Stainless steel | Passivation | Drawing |
Quick-Release Devices
Four quick-release part numbers in the same manual lock and release a plug-in module by hand, for service access where the front locking device is not used. They are supplied against the drawing rather than a dimension table.
Selection Guide
- Holding capacity5 kg (11 lb) per device under vibration condition A and 14 kg (31 lb) under condition B. Do not carry the 14 kg figure over to a condition-A installation.
- Rack interfaceB-class interface for the B clamps; lever handle assemblies follow the NAS1637 handle interface.
- Front releaseThe latch opens from the front of the rack, so an LRU can be swapped without removing adjacent units or reaching behind the chassis.
Specification
| Types | QSJ-A, QSJ-B, B2-clamp, B3-clamp, CLA43 |
|---|---|
| Handle interface | NAS1637 lever-type handle assemblies |
| Holding capacity | 5 kg (11 lb) per device under vibration condition A, 14 kg (31 lb) under condition B |
| Operating temperature | -55 °C to +125 °C (-67 °F to +257 °F) |
| Salt fog / mould | Acid salt fog 192 h and mould 28 days |
| Materials | Stainless steel, passivated; aluminium alloy housing with sand-blast hard anodize; titanium alloy hooks on the B3 clamps |
Typical Applications
Rack-mounted avionics LRUs, airborne equipment cases and ground-vehicle electronics that have to be held positively in the rack and released quickly for service, using the mounting dimensions of the interfaces already in use.
Engineering Resources
The other retention families that share the same module interface.
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26 part numbers for controlled insertion and extraction of module front panels.
Front Locking Devices
20 part numbers for LRU hold-down and quick release in rack-mounted avionics.
Vibration Isolators
27 part numbers of adaptive metal, friction and silicone mounts for 0.05 kg to 25 kg.
Technical Insights
Engineering insights on thermal management, fan selection, and defense electronics cooling.