Relay knockers are installed on hoppers, silos, and storage tanks used in processing coal, iron ore, gravel, and other bulk materials. These pneumatic devices use compressed air to drive a piston that delivers strong blows to loosen powdery materials stuck inside the containers. Designed to replace manual hammering, relay knockers improve efficiency—but the intense repeated impact can loosen standard fasteners, posing safety and maintenance risks.

• Repeated piston-driven impacts cause bolts and nuts to loosen over time.
• Components are typically installed at height, making retightening or inspections dangerous and labor-intensive.
• Falling hardware can lead to safety incidents, especially in busy industrial sites.
• Traditional fastening methods require frequent inspection cycles, increasing downtime and cost.

• Replaced standard fasteners with HARDLOCK Nut at all critical mounting points.
• Applied at elevated and vibration-prone locations, especially on heavy industrial bins and silos.
• Eliminated the need for external locking components like washers or adhesives.
• Provided long-term fastening stability, even under heavy repetitive shock loads.

• Improved Safety: Eliminated risk of hardware loosening and falling.
• Extended Maintenance Intervals: Reduced need for high-access retightening.
• Lower Operational Costs: Fewer repairs and inspections required.
• Enhanced Equipment Uptime: Reliable fastening under high-impact conditions.

HARDLOCK Nut delivers a maintenance-free, vibration-resistant fastening solution for relay knockers and other impact-prone industrial systems—helping facilities operate safely, efficiently, and with reduced manual intervention.

Industrial machinery operates under intense conditions—including high torque, vibration, heat, and shock—which can easily cause traditional fasteners to loosen or fail. HARDLOCK’s full line of fastening solutions provides unmatched stability and safety in these environments. Our technology is trusted across a wide range of equipment and applications, with tailored solutions for every fastening need:

• HARDLOCK Nut (HLN) for general anti-loosening performance in structural joints
• HARDLOCK Bearing Nut (HLB) for precise shaft locking under dynamic loads
• HARDLOCK Set Screw (HLS) for compact, reliable fixing where standard fasteners fail

Together, these products reduce maintenance cycles, extend equipment life, and ensure continuous, safe operation.

Key Machinery Applications for HARDLOCK Nut (HLN), HARDLOCK Bearing Nut (HLB), HARDLOCK Set Screw (HLS):

• Cement Mill (Liner Stopper)
• Pump Systems (Impeller Stopper)
• Concrete Mixers (Decelerator Shaft Locking)
• Tapping Machines (Ball Screw Locking)
• Power Cylinders (Drive Shaft Stopper)
• Injection Molding Machines
• Excavators (Drill Drive Shaft Stopper)
• Steelmaking Equipment
• Rock Drilling Machines (Straightening Roll Stopper)
• Hydraulic Breakers (Stopper Components)
• Conveyor Rollers
• Agitators (Impeller Stopper)
• Industrial Robots (Arm Assembly Locking)
• Large Hydraulic Presses (Cylinder Units)
• Die-Casting Machines (Core Pin Stopper)
• Compressors (Axis Stopper)

From factory floors to heavy-duty field equipment, HARDLOCK fastening systems—HLN, HLB, and HLS—offer a complete and proven solution for vibration-resistant, maintenance-free performance.