An overhead sweep reject uses a paddle or arm mounted above the conveyor to move a failed product across the belt into a controlled lane, chute or bin. It can suit stable packaged products and layouts where side-mounted actuators are difficult, provided the pack profile, belt width, sweep time, guarding and return position are proven for the application.
Reject from above
How does an overhead sweep rejector work?
A paddle starts from a guarded home position above or beside the product path. When the tracked failed pack reaches the reject zone, the mechanism sweeps across the belt and directs the product into the defined reject destination. It then returns home before the next product enters the operating envelope.
The paddle shape and height are matched to the pack. A face that works well on a rigid carton may catch a loose film edge or destabilise a tall container, so the product range must be assessed rather than assuming a standard arm will suit.
When is an overhead sweep useful?
The format can help where a conventional side pusher cylinder would project into an access route, clash with other equipment or require excessive reject-side depth. It can also sweep across a wider belt or move larger stable packs into a parallel lane.
For flexible, delicate or very close-spaced products, air blast, a retracting belt or another controlled transfer may be more appropriate. The choice depends on product behaviour and the time available to complete and recover from the sweep.
Position sensing and fail-safe monitoring
Home and operated position sensing can confirm that the arm moved and returned as expected. Independent product confirmation checks that the failed pack reached the reject path; these are different checks and both may be important to the site’s assurance strategy.
Guarding, access interlocks, obstruction risk and safe recovery are considered with the full conveyor layout. A mechanism that does not return home can raise an alarm or stop the line before an accepted pack reaches the reject zone.
Designing the receiving path
The sweep must deliver the pack into a chute, bin or transfer conveyor that contains it without bounce-back or bridging. Guide geometry, belt friction and the product’s centre of gravity are reviewed during trials, including the smallest and largest formats.
Key project considerations
- Rigid cartons and wrapped packs
- Larger stable products
- Wide-belt rejection
- Restricted side-mounted layout
- Reject or rework lane transfer
- Home-position and reject confirmation