Although many linear movements are relatively short distances, there are applications that require a travel distance of 12~15 meters or even longer. PBC Linear offers a range to meet the demand for various long lengths, including several options that can connect rails. If connecting rails are required for longer distances, we recommend rolling elements (wheel, ball, etc.).
Linear Slide Bearings
PBC Linear often receives inquiries from customers interested in our Gliding Surface Technology slide bearings for longer travel distances. Some of the products in this product range are e.g. Uni-Guide, Low Profile Uni-Guide and Mini Rail. In addition, our ceramic coated guides, also known as 'aluminum feather shafting', and ceramic coated rails, or 'feather rail', both fall into the slide bearing category.
Corrosion resistance and light weight are attractive features for this product line. While they are all excellent products and excellent choices for a wide range of applications, they are less suitable for coupling. The reason for this is that linear slide bearings and slides using slide bearing systems require exact running clearance where alignment is essential and couplings can cause obstructions due to misalignment. The Uni-Guide, Low Profile Uni-Guide and Mini-Rail carriages are also matched to the rails, making rail extensions problematic.
Rolling elements
As mentioned before, the product series with wheels, rollers or balls are the best candidates to pass a coupling in rails/guides. We will take a closer look at some of those product series that are suitable for long lengths, starting with Roller Pillow Blocks and then with Redi-Rail, Hevi-Rail and IVT linear guides.
Roller Pillow Blocks
Roller Pillow Blocks use round shafts as guides. Large cam followers in the roller block provide industrial strength performance for long travel distances and are highly resistant to contaminated environments. For very long travel distances we recommend supporting the hardened steel or hardened stainless steel shafts on an aluminum support rail. The shaft and support assembly (SRA) can be coupled together for long travel distances and the low friction rollers can easily pass through coupling points and misaligned or sagging guides.
• Maximum continuous length for a rail: 4.57 meters (15 feet).
• End connection: low-friction rollers can compensate for minor alignment errors and sagging guides.
Redi-Rail
Redi Rail is a very versatile product and can be mounted to utilize both radial and axial load capacity. After the reference cycle of the coordinate axis below, a load in the Y direction can utilize the radial load capacity. A load in the Z direction will apply force to the axial load condition. The Redi-Rail metric series is available in 3, 4, and 5-wheel slides and offers a pre-load option.
• Maximum continuous length for a rail: 5.79 meters (19 feet).
• End connection: The coupled rails are sufficiently accurate in pick and place applications. No self-aligning function or floating option, so alignment is important and one of the main challenges for parallel construction.
Hevi-Rail
Hevi Rail is mostly used in applications that do not require too much accuracy. The rails are made of standard structural steel and are therefore easy to weld, making it possible to grind the connection smooth for smooth transitions between the rails. Due to the high load capacity, this is a good choice for heavy loads over longer distances.
• Maximum continuous length for a rail: 7 meters (23 feet).
• End connection: easy to weld.
Integral-V Linear Guides
Integral-V technology offers a range of rail profiles and associated carriages. The maximum length of most profiles is approximately 4 meters (12 feet), sufficient for most applications, but can be easily coupled for longer runs. The V-profile wheel allows for easy passage of the coupling between the rails. Most profiles use a single rail due to the high moment. The adjustable pre-load in combination with a top speed of 10 m/s makes the IVT a unique choice for many applications.
• Maximum continuous length for a rail: approximately 4 meters (12 feet).
• End connection: the V-profile wheel ensures easy passage of the rail connections.
For more information: info@eltrex-motion.com
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