What is a ball transfer unit?
A ball transfer unit (BTU) is a mechanical component used to enable smooth and multi-directional movement of objects on a surface. It's essentially a ball-bearing system where a large load-bearing ball rotates on a number of smaller balls housed inside a hemispherical enclosure. These units are typically installed in a base or table to create a surface over which objects can easily move in any direction with minimal friction. In this guide, we’ll help you understand what you need to know about ball transfer units, covering:
How do ball transfer units work?
What to know about load capacity
Different types of ball transfer units
Advantages & disadvantages of ball transfer units
How do ball transfer units work?
A ball transfer unit features a central ball bearing enclosed within a tubular casing, which is partially restricted. This restriction securely holds the ball bearing in place while allowing it to rotate freely, with a portion extending beyond the casing. Beneath the central ball, a layer of smaller balls is arranged in a hemispherical cup, ensuring smooth and low-friction movement in all directions.
Multiple ball transfer units are then mounted on a flat plate or runner. These plates are arranged in rows on the conveyor bed, forming a surface of freely rotating balls for effortless material transportation. The modular design facilitates easy replacement of damaged units, and the compact size and low profile make them suitable for applications where other options are impractical.
Where are they used?
Ball transfer units are essential components used in a range of industries, providing efficient and reliable solutions for moving objects smoothly across various surfaces. Their omni-directional capabilities and ease of use make them valuable in manufacturing, logistics, and other applications.
Manufacturing and logistics
In manufacturing, ball transfer units streamline production processes by enabling the movement of materials between machines and workstations. They’re commonly used to improve efficiency and reduce manual labour:
● Conveyor systems: A ball transfer conveyor increases the capacity and flexibility of conveyor systems, allowing for seamless object transfer and handling heavy loads.
● Assembly lines: These units enable the movement of components between workstations, improving productivity and reducing the risk of damage. Inspection stations also use a ball transfer table.
● Loading docks: Ball transfer units expedite the loading and unloading of vehicles, ensuring efficient cargo handling.
Specialised applications
Beyond manufacturing and logistics, ball transfer units have found applications in diverse fields:
● Military: They are used in cargo handling equipment to move supplies and equipment efficiently.
● Air cargo: Roller decks equipped with ball transfer units enable quick and secure loading and unloading of aircraft.
● Food processing: These units facilitate the movement of food products in low-temperature environments, reducing the risk of contamination.
● Horticulture: Ball transfer units help transport delicate flowers and plants safely within refrigerated storage facilities.
View our range of ball transfer units
What to know about load capacity
When you’re looking at the specifications of ball transfer units, you’ll see either ball-up load capacity or ball-down load capacity . It’s important to know what these mean.
Ball-up load capacity
This is the maximum weight the ball transfer unit can support when the large ball is oriented upwards, which is typical in most material-handling systems. The load rests directly on the exposed, rotating ball, which distributes the weight across the smaller internal ball bearings.
● Application: Used in conveyor systems where objects are placed on top of the ball transfer units and need to move in various directions without lifting.
Different types of ball transfer units
Our ball transfer units come in various designs to suit different applications and load capacities. They’re designed with a dirt exit hole and a woollen felt seal to ensure optimal performance and longevity.
Ball transfers – Euro ball
Ideal for both flat and irregularly shaped items, Euro ball transfers provide reliable support and enable easy movement in any direction. Commonly used in cargo and baggage handling, assembly lines, machine loading, sliding door systems, and machine tables.
Resists temperatures between -30°C to 70°C.
Ball-up load capacity: From 10 kg to 610 kg
Materials: PA, carbon steel, stainless steel
Heavy-duty ball transfer unit
Corrosion resistant and featuring a ball that rolls within a metal or plastic casing, these heavy-duty ball transfer units enable the omni-directional movement of heavy objects. Ideal for applications requiring the movement of heavy items, such as cargo and baggage handling, assembly lines, machine loading, sliding door systems, and machine tables. Commonly used in heavy industries like automotive and shipping. No lubrication needed.
Ball-down load capacity: From 25 kg to 500 kg
Materials: Stainless steel, carbon steel, nylon
Spring-loaded ball transfer
Designed to minimise damage caused by shock loads and accommodate dimensional changes due to temperature variations. Corrosion resistant, this spring-loaded ball transfer automatically adjusts to distribute loads evenly. Ideal for applications such as shears, presses, and moulding machines. Commonly used in heavy industries like manufacturing, automotive, and shipping. Ball can be oriented up or down.
Ball-up load capacity: 10 kg and 35 kg
Ball-down load capacity: 10 kg and 35 kg
Material: Steel
Mini-ball transfer unit
Features low-friction ball bearings that enable the omni-directional movement of products on flat surfaces. The mini-ball transfer unit is ideal for applications such as measuring equipment, guides for small linear motion (eg, photocopier slides), material transfer in clean rooms, and miniature mechanisms. Available with both flat and angled tops to suit various needs.
Ball-up load capacity: From 5 kg to 30 kg
Materials: Stainless steel, chrome steel, carbon steel
Low-profile ball transfers
Designed with two or three flange fixing holes, depending on the specific ball transfer unit. Features low-friction ball bearings that enable the omni-directional movement of products on flat surfaces. Designed for use in tight spaces with limited clearance between applications and the surface, low profile ball transfer units are ideal for applications such as cargo and baggage handling, assembly lines, machine loading, sliding door systems, and machine tables. Commonly used in heavy industries like manufacturing, automotive, and shipping.
Ball can be oriented up or down.
Ball-up load capacity: From 4 kg to 140 kg
Ball-down load capacity: From 2 kg to 100 kg
Materials: PA, carbon steel, stainless steel
Medium-duty ball transfers
Featuring a large, low-friction bearing ball supported by multiple small balls encapsulated in a hemispherical cup. The large support area provides a balance of stability and large load capacity. Suitable for applications requiring the movement of moderately heavy objects, such as cargo and baggage handling, assembly lines, machine loading, sliding door systems, and machine tables. Ball can be oriented up or down. Also available with ball oriented down.
Ball-up load capacity: From 20 kg to 140 kg
Ball-down load capacity: From 10 kg to 60 kg
Materials: Zinc, steel, stainless steel
Advantages & disadvantages of ball transfer units
Ball transfer units provide efficient and reliable solutions for moving objects across various surfaces. But there are some drawbacks.
| Advantages | Disadvantages |
|---|---|
| Low Maintenance: Reduces downtime and operating costs | Sensitivity to uneven surfaces: Less stable, leading to uncontrolled movement |
| Durability: Can withstand harsh environments | Load capacity limitations: Excessive pressure can cause damage – use the right unit according to load capacity |
| Versatility: Can use ball up or ball down on some some units | Noise: Prolonged use may generate noise |
| Improved efficiency: Optimises material flow | Debris ingress: While our units are designed with a dirt exit hole, other units may not have this feature |
| Load distribution: Evenly distributes the weight of objects when used in rows or grids | Speed limitations: At high speeds, the precision of movement may be compromised |
How to install ball transfer units
Follow these steps for installing ball transfer units:
1. Determine the Layout
Decide on the pattern in which you’ll place the ball transfers. The spacing between units depends on the size and weight of the items being moved. Generally, the distance between the units should be slightly smaller than the smallest dimension of the item to ensure even support.
Tip: The units are typically installed in a grid on a flat surface or conveyor bed. This allows for omni-directional movement.
2. Surface Preparation
The surface where you’ll install the ball transfer units should be flat and smooth. Any unevenness may result in improper weight distribution or interfere with movement.
Tip: Mark the positions for each ball transfer unit based on the layout you've chosen. Precision is key for ensuring that all units align properly and function smoothly.
3. Mounting Options
This depends on the type of unit and the surface you’re attaching the ball transfer units to.
● Flanged mounting
Some of our ball transfer units come with a flange or mounting plate with pre-drilled
holes. This allows you to screw or bolt the unit directly into the surface.
1. Align the unit with the marked location.
2. Use screws or bolts to secure the flange to the surface.
● Threaded mounting
If your chosen unit has a threaded stud on the bottom, you can screw the unit into pre-drilled and threaded holes.
1. Drill and tap the holes in the surface according to the unit’s thread size.
2. Screw the ball transfer unit into the hole by hand or using a tool for a secure fit.
Tip: If you’re opting for Euro ball transfers, use fixing clips. These are placed into the seated position before fitting the unit into the mounting hole. Once the clips are in place, the ball unit is inserted, and the clips lock the unit securely in position to ensure stability during operation.
4. Check for proper alignment
Once all the ball transfer units are installed, check that they are level and that their balls protrude uniformly from the surface. Misalignment can cause uneven movement or failure to support the load properly.
Tip: Place a load on the units to test how smoothly it moves in all directions. If there are any points where movement is restricted or uneven, check the units for proper seating and alignment. Make adjustments if necessary.
Alternatives to ball transfer units
There are several alternatives to ball transfer units that can provide similar functionality for moving, guiding, or transferring loads in various applications.
Linear guide rails and carriages for linear motion
Linear guide rails provide a viable alternative to ball transfer units when you need accurate and controlled forward and back motion. These systems comprise two primary parts: a rail and a carriage. The rail is a long, straight structure anchored to a stable surface, while the carriage is a movable block that travels along the rail. With bearings designed to reduce friction, the carriage allows for smooth and efficient movement.
These guide rails are particularly effective in scenarios where precision and low friction are crucial. They can support dynamic loads and are engineered to withstand challenges like impact, vibration, and fatigue, making them ideal for high-demand settings.
Linear carriages are important to your linear motion systems, designed to enable smooth and precise movement along linear paths. Our range is vast, from carriages with ball-retention mechanisms to carriages with flange variations.
Linear shafts and linear bushings
If you only need linear motion, another alternative to ball transfer units are linear shafts. These are precision-machined bars designed to provide support and guide movement in a straight line.
A linear shaft works with linear bearings – also called linear bushings – which run along the shaft to create a smooth, linear guide system. These linear bearings, sometimes referred to as linear ball bushings, move along the hardened surface of the shaft. With supports placed at either end, linear shafts and bearings are straightforward and quick to install, making them ideal for guiding equipment in linear motion.
Linear bushings, or bearings, consist of a cylindrical outer shell and an inner carriage containing rows of ball bearings. These low-friction bearings enable smooth movement along the linear rail or shaft, allowing for accurate and easy linear motion in machinery and systems. Examples include CNC machines, 3D printers, and automated manufacturing equipment.
Our experts have put together these guides to help you learn more: How to select the ideal linear shaft for your application and How to select the right linear bushings for your application.
Download free CADs
Free CADs are available for most solutions, which you can download. If you’re not quite sure which ball transfer unit will work best for your application, our experts are always happy to advise you.
Whatever your requirements, you can depend on fast despatch.
Questions?
Email us at sales@essentracomponents.co.uk or speak to one of our experts for further information on the ideal solution for your application 0345 528 0474.