Why consider Gravity Roller Conveyors – A cost effective solution for moving products through your factory to aid operators and free up space.
A gravity roller conveyor is a non-powered material handling system that uses the force of gravity or momentum to move goods along a path of free-spinning rollers. Typically, more affordable and simpler than powered systems, they are often used for light- to medium-duty applications. However, they are great for moving Pallets which would otherwise require Pallet trucks or expensive Forklifts to move these goods around.
How they work
- The system: A gravity roller conveyor consists of a series of rollers mounted in frames. There are endless frame designs, specific to customer requirements and these frames can be mounted directly to the floor, on support structures or in rack systems to make either a FIFO (First in, first out system or push back rack system.
- The movement: When these are installed at an angle, products will freely flow from one end to another. Sometimes for heavier loads break rollers may be required to control the speed of goods, especially when it comes to heavy goods or pallets. When installed horizontally, goods are manually pushed from one station to the next.
- Optimal conditions: Generally, objects, cartons, crates pallets etc, should have a flat surface for smooth transfer across the rollers. The roller pitch should be carefully designed with 2 main factors to consider. Base stability of the product (A good rule of thumb is always have 3 rollers in contact with the product) and the load rating of the rollers themselves.
There are a few Common types cof Gravity Roller Conveyors:
- Straight conveyors: The most basic and versatile type, used for moving products in a direct, straight line.
- Curved Conveyors: These can go around corners, covering almost any angle but the radius is generally governed by the roller design and typically we use a 900mm inside radius for small light goods but avoid gravity bends for pallets. Curved conveyors can use tapered rollers or split parallel rollers to compensate for the speed variable.
- Flexible Conveyors: These are expandable conveyors that can go around curves or go in a straight line. The are also very compact and store well.
- Skate Wheel Conveyors: Instead of the full length rollers, these are multiple wheels mounted in a frame, generally on common shafts. They offer very low rolling resistance. These are a lightweight, best used with very light cartons or products.
Applications and uses
Gravity roller conveyors are widely used in a variety of material handling applications to simplify the movement and distribution of goods.
- Warehousing and distribution: Moving boxes, cartons, and totes between workstations or from receiving to storage.
- Assembly lines: Transporting components or products from one assembly station to the next.
- Packaging and sorting: Assembling goods and moving finished packages to the shipping area.
- Vehicle loading and unloading: Creating temporary conveyor lines to move goods into or out of trucks and trailers.
- End-of-line accumulation: Allowing products to queue at the end of a line before being picked up.
Advantages
- Low cost: They require no motors or complex machinery, resulting in a lower initial investment and reduced operational costs.
- Energy efficient: Since they do not use electricity, they have zero energy consumption.
- Simple maintenance: With fewer moving parts, maintenance requirements are minimal. The rollers and axles are often spring-loaded for easy replacement.
- Quiet operation: The lack of motors makes them a much quieter option than powered conveyors.
- Versatility: Modular designs allow for easy expansion and reconfiguration to adapt to changing needs.
Disadvantages
- Limited control: Unlike powered systems, they offer no control over the speed or spacing of products, which can lead to product accumulation.
- Inconsistent speed: The speed of products can vary depending on their weight and the steepness of the incline.
- No horizontal or uphill movement: They cannot transport products over flat surfaces for long distances or up an incline without manual assistance.
- Not for all products: They are not suitable for transporting items with uneven, soft, or unstable bottoms unless placed in a tote or box.
