Sprag clutches are used in a wide variety of applications, from bicycles to drilling machines.
A sprag clutch operates in one direction. When it comes to stopping motion from moving in the opposite direction, you typically have three main areas: indexing, backstopping, or overrunning.
In this article, we will dive into each different mode of operation to help you understand the differences of each.
Our Clutch Product Line
Our extensive line of sprag-type freewheel clutches is designed to satisfy most sprag clutch needs. Our three main product categories are:
- Complete Sprag Clutch Units: Created for big loads that need lots of torque. These sprag clutches are the most robust because they are made with both roller and ball bearings.
- Ball Bearing Sprag Clutch Units: This is our most economical line of clutches. Good for most jobs & uses. All the sizes are matched to radial bearing sizes.
- Sprag Clutch Inserts: Made for those who don’t need a housing or shaft for their clutch application: They come with a cage, a spring and sprags.
Three Options for Stopping Force
The Backstopping Clutch
A backstop clutch is commonly used for safety precautions.
If a machine is designed to carry heavy objects, the backstop clutch needs to hold the object weight if the machine doesn’t function properly. An example would be if the power goes out in an elevator, the backstop clutch can hold the weight in place & protect the people it’s carrying.
Backstop Clutch Machines & Operation Examples:
- Conveyors & Winches: Stop Loads
- High Voltage Switching: Safety Device
- Textile Machine: Material Feed Protection
- Industrial Fan: Motor Protection
The Indexing Clutch?
An indexing clutch pushes motion in a circular direction and then allows it to idle or stop. The most common example is an assembly line or automatic production line.
A production line that moves to one position, stops, waits and then moves is a good example of how an indexing clutch works. The indexing motion cycle is controlled and protected with the use of Sprag Clutches.
Many types of conveyors, assembly machines and production machines use an indexing sprag clutch to do business and for added safety precautions in case of motor or electrical failure.
Indexing Clutch Machines & Operation Examples:
- Copiers: Paper Feeding
- Furniture Production: Glue Roller
- Food Production: Bottling Plant
- Sewing Machines: Material Feeder
- Automatic Winch: Controlled Raising/Lowering
The Overrunning Clutch
An overrunning clutch prevents direction from being pushed in the reverse direction. The clutch allows idle spinning to keep going without engagement of force. The most common example is the bicycle.
Overrunning Clutch Machines & Operation Examples:
- Conveyors: Speed Compensation
- Mixers: Motor Protection
- Motorcycles: Gear Box or Transmission
- Packaging Machine: Spins Down Freely
- Printing Press: Ink Roller Drive