NQ3 HQ3 PQ3 Core Latch Spring Steel Retaining Spring for Triple Tube Wireline Coring Tools

Q3 series special retaining springs (also known as locking pins, core claws, or Core Latch in the industry) are the core retaining core components for NQ3, HQ3, and PQ3 three-layer pipe rope retrieval drill tools. They are combined with locking pin seats, retaining rings, centering rings, and seat rings to form a complete locking pin assembly. The structure adopts an integrated elastic cage-like design, specifically tailored for fractured rock layers, weathered sandy soil, and loose interlayers that are prone to core loss. The elastic claws securely hold and support the core, fundamentally reducing the problems of core slippage and fragmentation, significantly increasing the core retrieval rate in complex formations. They are essential wear-prone drill tool components for geological exploration and geothermal drilling.

Structure and Working Principle
Cage-like elastic claw structure
Multiple evenly distributed elastic spring claws are integrally stamped and formed, with the top constricted and the bottom capable of elastic expansion; during drilling and lowering, the spring claws are compressed by the core and expand, allowing the core to smoothly enter the inner tube; when lifting the drill tool, the claws rebound and constrict, firmly holding the core and preventing it from falling.
Ring-shaped base reinforcement design
The bottom is widened with a fixed ring, featuring riveted reinforcement points. When assembled with the locking pin seat, the assembly is evenly stressed, making it less likely to crack or disintegrate during long-term deep well operations, and suitable for deep hole heavy-duty drilling conditions.

1. Original factory special spring steel material, with long-lasting elasticity and anti-fatigue properties
The spring is made of special spring alloy steel and is formed by stamping. It undergoes overall quenching and surface blackening for rust prevention treatment. The spring plate has stable rebound and can withstand repeated opening and closing without fatigue fracture; it is not prone to breakage. It is resistant to mud corrosion and can withstand hard rock impact and wear. It can be used stably with both clean water and mud drilling media.
2. Even force distribution among multiple claws, stable core extraction without core fragmentation
The multi-lobed elastic claws are evenly adhered to the outer wall of the core sample, distributing the force evenly and preventing compression and fragmentation of loose or broken rock samples, ensuring the integrity of the core sample and meeting geological sampling and testing standards.
3. DCDMA international standard size, universal interchangeability with all brands
Strictly following the DCDMA three-layer pipe drilling tool standard processing, the inner diameter, height, and gap size of the claws are precise. It can be matched with all brands of NQ3/HQ3/PQ3 three-layer pipe inner pipe assemblies, and can be disassembled and replaced without any jamming.
4. Reinforced riveting process, less prone to disassembly in deep wells and heavy loads
The bottom base and elastic claws are reinforced by multiple riveting points. Compared to ordinary welded restraining springs, it has stronger tensile and impact resistance. In 3000-meter ultra-deep hole operations, there is less risk of claw plate detachment or cracking.
5. Lattice-through structure, smooth core discharge without core blockage
The spring gap is large, and during drilling, the mud and rock powder can flow smoothly, without being blocked or jammed by the elastic claws. Long-term construction does not require frequent disassembly and cleaning.