Manufacturing Process of Apron Feeder
The manufacturing process of apron feeder consists of frame fabrication, machining of drive sprocket assembly, machining of driven sprocket assembly, machining of apron pans, machining of traction chains, and machining of support rollers. Detailed descriptions are given as follows.
Frame Fabrication of Apron Feeder
The frame features excellent shock and vibration resistance, a structure convenient for assembly, disassembly and adjustment of installation angle, with its self-weight minimized as much as possible.
When the center distance between sprockets is ≤ 9 m, the frame adopts an integral structure; when the distance exceeds 9 m, a sectional split frame is applied.
For the bearing housings mounted at the drive and take-up ends of the apron feeder frame:
- Parallelism tolerance of two corresponding mating planes: 1.0 mm
- Spacing deviation of corresponding mounting holes: ±0.5 mm
- Diagonal difference of hole layout: less than 2.0 mm
Tolerance requirements for main frame beams:
- Straightness tolerance: 1.5/1000, with a maximum deviation of 10 mm over the full longitudinal length
- Frame diagonal difference: 1/1000, capped at 10 mm
Geometric tolerance requirements for shaft centerlines:
- Perpendicularity tolerance of drive shaft centerline relative to the central plane of the frame: 1/1000 of the center distance between the two drive bearings
- Parallelism tolerance of take-up shaft centerline relative to drive shaft centerline: 0.5/1000 of the actual sprocket center distance
Drive Sprocket Assembly & Head Drive Unit of Apron Feeder
This section serves as the power and transmission component of the apron feeder, composed of an electric motor, reducer and drive sprocket assembly.
Variable-frequency speed regulation is adopted for the motor to realize adjustable feeding capacity as required by production processes.
The apron feeder’s drive sprocket assembly adopts a head sprocket, with tail sprockets acting as supporting rollers to drive two complete bulldozer track assemblies, and the apron pans travel along the support rollers.
Driven Sprocket Assembly of Apron Feeder
The driven sprocket assembly is equipped with a screw take-up mechanism, mainly comprising a shaft, two supporting rollers, bearings, bearing housings, disc springs and take-up screws.
The supporting rollers are fixed onto the shaft via keys, and double-row self-aligning roller bearings together with bearing housings are fitted at both ends of the shaft.
Apron Pans of Apron Feeder
The apron pans adopt an arc overlapping design, fabricated by welding low-alloy steel plates, featuring high mechanical strength and superior wear resistance. Adjacent pans overlap tightly to prevent material leakage during operation. Reinforcements are arranged on both top and bottom of each pan to enhance load-bearing capacity.
- Material grade of apron carrying plates: Q235 or higher
- Gap at overlapping joints of adjacent pans: no more than 3 mm
- Coaxiality tolerance of centerlines of roller brackets at both ends of each pan: 0.5 mm
- Perpendicularity tolerance of roller bracket centerline relative to the longitudinal centerline of the pan: 0.5 mm
- Stress relief treatment shall be performed after pan welding.
Traction Chains of Apron Feeder
Heavy-duty apron feeders generally adopt standard bulldozer track chains (commonly referred to as tank tracks) with a standard pitch of 216 mm as traction chains.
- Breaking load of a single chain: over 125 tons
- Service safety factor: greater than 6 to 8
Sufficient tensile strength is guaranteed for long-term service under regular maintenance.
Support Rollers of Apron Feeder
Support rollers are designed as standard traction rollers fitted with sealed lifetime-lubricated bearings, mounted on the main feeder frame. The rollers are arranged with properly optimized spacing to provide sufficient support for the complete chain assembly.
