The internal structure of a swivel wheel sorter typically consists of wheel conveying units, a conveying drive and transmission system, a synchronized steering mechanism, a supporting frame, and auxiliary components. Each section performs a different function, including parcel conveying, wheel-angle adjustment, power transmission, and structural support. Together, they enable continuous conveying and automatic diverting.
The drive and module arrangements vary between manufacturers. For example, some machines use a geared motor, multi-ribbed belt rollers, and O-rings to transmit conveying power, while a servo motor and linkage mechanism control the synchronized steering of the wheels. The actual internal structure should be assessed against the machine's mechanical drawings and drive configuration.
Wheel conveying units
The wheel conveying unit directly supports and transports items. It typically consists of swivel wheels, rollers, shafts, bearings, support bases, and related connecting components.
The wheel surface contacts the bottom of the item and provides conveying force through rotation. Each wheel assembly is mounted on a steerable support structure. When the steering mechanism changes its angle, the direction of item movement changes accordingly, allowing the item to continue along the main line or move onto a side conveyor.
Some models use rubber or polyurethane coverings on the roller or wheel surfaces to improve contact friction and reduce rigid contact between the item and the conveying unit. The surface material should be selected according to parcel weight, bottom geometry, friction requirements, and machine design. Not all swivel wheels use the same surface covering.
Multiple wheel units are arranged at specified intervals. Proper spacing provides adequate support for items of different dimensions and helps prevent small items from becoming unstable on the conveying surface. It is important to distinguish wheel spacing from parcel spacing. The latter is mainly controlled by the upstream induction and conveying system.
Conveying drive and transmission system
The conveying drive provides the power needed to rotate the wheels or conveying rollers, moving items along the main conveying direction. Its configuration depends on the machine design. Common arrangements include geared motors with belt transmission, motorized roller drives, and friction-drive systems.
One example is an electric-linkage swivel wheel sorter that uses multi-ribbed belts and O-rings. Its power transmission can be divided into several stages.
Geared motor output. The geared motor is mounted on the frame or motor mounting plate. Its output shaft drives a multi-ribbed belt pulley.
Power transmission through multi-ribbed belts. The pulley drives the multi-ribbed belt roller, while adjacent rollers can also be connected through multi-ribbed belts to transmit power.
O-ring drive to the swivel wheels. The multi-ribbed belt roller transfers power to the swivel wheels through O-rings. The wheels rotate and move items along the conveying direction.
This arrangement distributes motor power to multiple conveying units and supports continuous item movement. The design must also account for belt tension, transmission contact, wear, and maintenance access.
However, a multi-ribbed belt and O-ring transmission is only one possible arrangement. Some swivel wheel sorters use direct-driven motorized rollers, while others use friction transmission between drive rollers and conveying rollers. This particular transmission chain should not be treated as a universal configuration for all swivel wheel sorters.
Synchronized steering mechanism
The synchronized steering mechanism changes the mounting angle of the swivel wheels and is responsible for changing the direction of item movement. It may include a servo motor, connecting rods, rocker arms, shafts, support structures, and position sensors. The actual combination depends on the steering design.
In an electric-linkage arrangement, a servo motor drives a primary connecting rod through its output shaft. Secondary connecting rods transmit the movement to other wheel units, allowing multiple wheels to turn synchronously in the required direction.
When an item needs to continue along the main conveyor, the wheels can remain in their neutral position. When the control system requires the item to move to the left or right, the servo motor operates the linkage mechanism and changes the wheel angle to create the required diverting direction.
Some machines also use photoelectric proximity sensors, detection plates, or other position-feedback devices to confirm that the steering movement has reached its required position. The control system uses these feedback signals to monitor the actual wheel angle and adjust the drive operation when necessary.
It is important to distinguish the sorting task from the steering action. The higher-level control system normally determines the destination based on barcode, QR code, or other identification data and sends the required direction to the machine control system. The servo motor and linkage mechanism execute the steering movement; they do not normally perform the complete parcel identification and destination assignment process themselves.
Frame and support structure
The frame is the main load-bearing structure of the swivel wheel sorter. It supports and locates the wheel units, transmission components, steering mechanism, and electrical equipment.
Frames are commonly assembled from structural profiles, steel plates, side panels, crossmembers, and mounting plates. Frame stiffness and assembly accuracy affect the relative positions of the swivel wheels, the flatness of the conveying surface, and the installation condition of the transmission components.
In modular swivel wheel sorters, individual wheel units are often attached to the frame through support bases or mounting plates. This arrangement makes it easier to remove, replace, and maintain individual modules. It also allows the number of wheel units to be adjusted according to the conveyor layout.
Frame design should account for parcel loads, operating vibration, installation space, and maintenance access. For equipment operating continuously over long periods, mounting looseness, frame deformation, and wear at support points should be checked regularly.
Covers, base plates, and auxiliary components
In addition to the conveying and drive mechanisms, swivel wheel sorters may include covers, base plates, bearing housings, belt tensioners, cable supports, and protective components.
Covers and base plates enclose or protect internal components, connect structural sections, and provide mounting support. Some covers and base plates also contribute to overall frame rigidity, depending on the machine design.
Belt tensioning components maintain the required tension in multi-ribbed belts or O-rings. Proper tension helps reduce slipping and belt misalignment during power transmission. A tensioning assembly may include a tensioning plate, adjustment block, threaded rod, and related mounting hardware. The exact arrangement depends on the transmission design.
Bearings and lubrication components support rotating shafts, rollers, and swivel wheels while reducing rotational resistance. During maintenance, check bearing wear, abnormal noise, rotational clearance, and lubrication condition. Follow the manufacturer's maintenance requirements for lubrication and replacement.
Cooling and electrical accessories are configured according to motor and drive loads. Some machines include fan brackets or mounting positions for cooling fans, but a fan is not a standard component on every swivel wheel sorter. The need for additional cooling depends on motor power, operating cycle, installation environment, and the manufacturer's thermal design.
How do the internal components work together?
During operation, the conveying drive rotates the swivel wheels and moves items along the main conveying direction. The higher-level control system determines the required destination from the item identification data and sends the corresponding command to the machine control unit.
When an item reaches the designated diverting position, the synchronized steering mechanism adjusts the wheel angle according to the control command. The wheels continue to provide conveying force while changing the direction of item movement, guiding the item onto the target branch conveyor. Where position sensors are provided, they report the actual steering position to help the control system confirm that the movement has been completed.
The internal design of a swivel wheel sorter must therefore address more than the conveying capacity of individual wheels. Coordination between the conveying drive and steering mechanism, module installation accuracy, transmission stability, and maintenance access are also important considerations.
In addition to precision mechanical components for logistics conveying and sorting equipment, Hansheng Automation provides custom CNC precision machining services. We manufacture non-standard precision components according to customer-supplied drawings and support individual parts and small-batch production.
