Flexible Couplings & Rigid Couplings
Couplings are devices used to connect two shafts together and are divided into two categories: Rigid and Flexible Couplings
Both flexible and rigid couplings are used for the purpose of transmitting power. However, rigid couplings are limited in comparison to flexible couplings. Flexible couplings are designed to accommodate: angular misalignment, angular offset, axial movement, and various types of load conditions. Rigid couplings are used where shafts are already positioned in precise lateral and angular alignment. Their rigid design does not allow for any misalignment between shafts, but they are generally able to transmit more power than flexible couplings.
With many styles and types of couplings available, your application conditions must be clearly understood. ...Our experienced engineers can solve even the most difficult application issues and find the right coupling solution for your application. SDP/SI offers a wide variety of both rigid and flexible couplings. Many of our precision couplings are designed with our unique Fairloc® Hub design, including the Miniature Fairloc® Bellows Coupling and the Neo-Flex Coupling. Modular Bellows Couplings can be configured to accommodate various shaft diameters and provide backlash-free torque transmission. Magnetic Disk Couplings are built to handle up to 3° of angular offset and operate in temperatures up to 284°F.
Flexible Shafts can be used in applications where the load must be moved in many directions. Flexible Shafts are stiff in torsion and very compliant in bending and lateral misalignments. They are extremely useful where the load is located in a remote position requiring many gear and shafting combinations. The basic design considerations are torque capacity, speed, direction of rotation, bend radii and service conditions.
Metal and Molded Universal Joints
Universal joints are used to transmit power, motion, or both. Cardan joints or Hooke joints are the most common and consists of two yokes, one on each shaft, connected by a cross-shaped intermediate member called the ”spider”. The angle between the shafts is called the operating angle. It is usually constant during operation, but not necessarily so. Good design practice calls for low operating angles, often less than 25°.
Universal joints are available in steel or in thermoplastic body members. For maximum load-carrying capacity, for a given size, a steel universal joint should be selected. Universal joints with thermoplastic body members are used in light industrial applications in which their self-lubricating feature, light weight, negligible backlash, corrosion resistance and capability for high-speed operation are significant advantages.... Ball-jointed universals are used for high-speed operation and for carrying large torques. They are available in miniature and standard sizes.
SDP/SI pioneered the concept of combining the exceptional qualities of selected plastic materials with different metals to create products which incorporate both. “SUPER-PLAST®” designs have the following advantages:
• Inexpensive replacement of metal components
• Dampens vibration
• Corrosive and chemical resistant
• Electrically insulated
SDP/SI offers an extensive selection of inch and metric dimensioned universal joints available in steel, stainless steel, acetal and acetal with brass spider and inserts as standard catalog items.
The molded universal joints can be manufactured to special requirements:
• Bores molded to accommodate square, “D” shape or hexagonal shafts
• Shafts molded into the components
• Zero backlash or components with built-in backlash
• Gears, pulleys or other components molded or assembled to couplings or universal joints
Call to discuss your special need or application.
Top Tips for selecting the right Flexible Coupling for optimal performance
Choose the Right Coupling for Your Servo System
Use our Coupling Selector Tool
Criteria for Power Transmission Couplings
Flexible Coupling Technical Information
View Custom & Secondary Operations
View Shaft and Shaft Accessories
Learn more about Fairloc®
Learn more about Shaftloc®
Materials: Brass, Bronze, Stainless Steel, Nickel, Steel, Aluminum, Neoprene, Nylon, Zinc
Bore Size: 0.0625 in. (1mm) - 1.750 in. (45mm)
Outer Diameter: 0.250 in. (6.4mm) - 3.700 in. (94mm)
Length: 0.480 in. (14.2mm) - 3.55 in. (90.3mm)
SDP/SI Bellows Couplings are flexible couplings designed to accommodate various types of load conditions. SDP/SI Hi-Flex Bellows Couplings are used for applications which require large amounts of shaft misalignment combined with low resultant radial loads on the bearings. SDP/SI Modular Bellows Couplings are configurable and provide high torsional rigidity for high speed torque transmission. A wide variety of bore sizes and combinations are offered to accommodate specific needs.
Materials: Aluminum, Stainless Steel, Steel
Bore Size: 0.094 in. (2mm) - 1.00 in. (12mm)
Outer Diameter: 1/4 in. (6.35mm) - 2 1/4 in. (31.8mm)
Length: 0.37 in. (20mm) - 3.50 in. (58mm)
SDP/SI Helical Couplings, or beam couplings, are another type of flexible coupling allowing for axial motion, angular misalignment and parallel offset. This coupling design features one-piece construction resulting in zero backlash. The coupling is made flexible by removing material from the piece in a spiral pattern. SDP/SI Helical Couplings are available in aluminum and stainless steel.
Materials (include): Aluminum, Stainless, Steel, Resin, Brass, Bronze, Steel, Iron, Nickel, Copper, Polymer, Rubber, Acetal, Neoprene, Nylon, Zinc, Silicone, Polyurethane, Polyimide, Polyethylene, Fiberglass
Bore: 0.0625 in. (1mm) - 1.750 in. (45mm)
Outer Diameter: 0.25 in. (6.4mm) - 3.70 in. (94mm)
Length: 0.375 in. (7mm) - 3.55 in. (90.3mm)
Flexible Couplings have the ability to compensate for shaft misalignment and are designed to accommodate various types of load conditions. No one type of coupling can provide the universal solution to all coupling problems; hence many designs are available, each possessing construction features to accommodate one or more types of application requirements. SDP/SI offers many styles of flexible couplings, such as bellows couplings, helical couplings, oldham couplings, universal joints, and flexible shafts.
Materials: Aluminum, Steel, Rubber
Bore Size: 3 mm - 16 mm
Outer Diameter: 15 mm - 39 mm
Length: 18 mm - 55 mm
For position accuracy and vibration reduction in a servo system, these couplings solve misalignment challenges in response-mandatory servo systems designed for the semiconductor manufacturing equipment industry, scanning equipment and many automation applications. Standard sizes available in. bores 3 mm thru 16 mm. Call for custom requirements.
Bore Size: 6 mm - 20 mm
Outer Diameter: 40 mm - 52 mm
Length: 48 mm - 56 mm
Two-and Three-Piece Junior Couplings are curved tooth gear couplings made of nylon. Designed to compensate for axial, radial and angular misalignment, they are lightweight and maintenance free.
Materials: Stainless Steel, Steel, Nickel
Bore Size: 0.125 in. (5mm) - 1.000 in. (19mm)
Outer Diameter: 1.06 in. (27mm) - 2.86 in. (73mm)
Length: 0.63 in. (15mm) - 1.00 in. (25.4mm)
A magnetic coupling transfers torque by using a magnetic field rather than a physical mechanized connection to transfer torque from an input shaft to the output shaft.
Because a non-contact magnetic bond is established between the two shafts, these couplings are most commonly utilized for liquid pumps and propeller systems where seals will wear out or break over time as the two surfaces slide against each other. Magnetic couplings use extremely strong natural magnets to transfer torque (without physically touching).
Materials: Stainless Steel, Nylon
Bore Size: 0.0625 in. (2mm) - 0.6250 in. (16mm)
Outer Diameter: 7/32 in. (5.6mm) - 1.0 in. (25.4mm)
Length(closed): 5/8 in. (15.9mm) - 1 7/8 in. (47.6mm)
Materials: Stainless Steel
Bore Size: 0.1248 in. - 0.2498 in.
Outer Diameter: 0.75 in.
Length: 0.87 in.
SDP/SI Precision Multi-jawed Coupling is a rigid coupling that accommodates minimal shaft misalignment. The helical gear coupling enables a positive connection between two shafts that can be disconnected or connected at any time when stopped.
Materials: Stainless Steel, Aluminum, Acetal, Brass
Bore Size: 0.125 in. (2mm) - .5625 in. (12mm)
Outer Diameter: 0.25 in. (6.4mm) - 1.62 in. (41.1mm)
Length: 0.50 in. (12.7mm) - 2.00 in. (50.8mm)
An Oldham coupling consists of three parts: one hub that is connected to the input shaft, one hub that is connected to the output shaft, and a floating member that is connected to the first two by tongue and groove in the center of the coupling. One side's tongue and groove is 90° or perpendicular to the other's tongue and groove. The input and output shafts rotate at the same speed as the middle member, around its center. Twice per rotation, the center traces a circular orbit around the halfway of the input and output shafts. To prevent backlash, springs are typically employed.
Oldham Couplings can accommodate lateral shaft misalignments up to 10% of nominal shaft diameters and up to 3° angular misalignments. Lubrication can be a problem but in most applications, can be overcome by choosing a coupling that uses a wear resistant plastic or an elastomer member in place of steel or bronze floating members.
Materials: Stainless Steel, Acetal, Aluminum, Steel, Brass
Bore Size: 0.09 in. (0.8mm) - 0.50 in. (15.0mm)
Outer Diameter: 0.125 in. (7mm) - 0.53 in. (27mm)
Length: 0.21 in. (7mm) - 1.00 in. (38mm)
Rigid Couplings have limited applications unlike flexible couplings. Rigid couplings do not have the ability to compensate for shaft misalignments are therefore used where shafts are already positioned in precise lateral and angular alignment. Because of their simple rugged design, rigid couplings are generally able to transmit more power than flexible couplings of comparable size. However, this is not an important advantage, unless the application is high horsepower.
Materials: Bronze, Brass, Steel
Flexible Shaft Diameter: 0.13 in. - 0.25 in.
Length: 24 in. - 48 in.
Materials: Stainless Steel, Steel
Flexible Shaft Diameter: 0.098 in. (1.7mm) - 0.250 in. (6.4mm)
Length: 3 in. (50mm) - 14 in. (355mm)
Materials: Stainless, Steel, Steel, Zinc
Bore Size: 0.0938 in. (2.5mm) - 0.6250 in. (20mm)
Outer Diameter: 3/16 in. (4.76mm) - 1 in. (32mm)
Length: 1 in. (25.4mm) - 7.30 in. (185mm)
Single and double joint stainless steel and alloy steel universal joints are offered with a variety of bore sizes. Miniature universal joints feature zero backlash, sealed-in lubrication and low inertia. Inverted design universal joints are small in size and lightweight for given torque capacity. These joints may be made into telescoping units by mating them with telescoping miniature ball splines.
Bore Size: 1/8 in. (2mm) - 3/8 in. (10mm)
Outer Diameter: 1/4 in. (6.3mm) - 5/8 in. (15.9mm)
Length: 3/4 in. (19mm) - 4 13/32 in. (111.8mm)
Plastic universal joints are inexpensive, dampen vibration, electrically insulating, and are well suited for low torque applications. We offer a wide variety of sizes and styles as standard catalog items. We can also manufacture them to specific requirements, please consult SDP/SI Engineering for further details.
Materials: Acetal, Brass, Stainless Steel
Bore Size: 0.125 in. (2mm) - 0.6250 in. (14mm)
Outer Diameter: 0.25 in. (6.3mm) - 0.625 in. (25.41mm)
Length(closed): 1.5 in. (38.1mm) - 10.1 in. (256mm)
Stainless steel telescoping universal joints are offered in a number of sizes and are heat and corrosion resistant. Telescoping miniature universal joints feature zero backlash and accommodate 1/4 axial motion. Molded universal joints with a molded slide extension or brass slide extension are available in a variety of sizes, shorter or longer lengths are available on special order.
Materials: Stainless Steel
Bore Size: 0.0938 in. (Solid) - 0.5000 in. (14mm)
Outer Diameter: 3/16 in. (4.76mm) - 1 in. (25.41mm)
Length: 1.0 in. (25.4mm) - 3 7/8 in. (98.6mm)
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