Technical Advantages of SLH Series Holdback Clutch

1. Zero Backlash Instantaneous Action
Precision-ground sprags engage immediately upon reverse rotation attempt. No lag, no backlash – your equipment stops before it can backdrive.

2. High Torque Capacity in Compact Design
The SLH series delivers exceptional torque density. You get the holding power you need without oversized mounting envelopes.

3. Heavy-Duty Bearings for Arduous Duty
All clutches are fitted with high precision heavy-duty bearings, rated for continuous operation in demanding environments such as mining, quarrying, and cement plants.

4. Enhanced Sealing for Hostile Environments
Large clutch sizes offer enhanced sealing options to exclude dust, water, and contaminants – critical for outdoor conveyors and elevator head shafts.

5. Flexible Lubrication Options
- Grease lubrication: Ideal for difficult-to-access locations or when high inner race overrunning speeds are required.
- Oil lubrication: Available for applications where oil bath systems already exist.

6. Non-Backdriving Design
Specifically engineered for backstopping applications where the load must never reverse. Unlike standard overrunning clutches, the SLH series is optimized for low-speed, high-torque holdback duty.

Typical Applications for SLH Series Holdback Clutch

The SLH series is purpose-built for non-backdriving applications where reverse rotation would cause equipment damage, material spillage, or safety hazards.

Inclined Belt Conveyors
Prevents the loaded belt from running backward during power failure, emergency stop, or motor brake failure. Protects the conveyor structure and prevents material pileup at the tail.

Bucket Elevators
Stops the filled buckets from reversing and dumping material back into the boot section. Prevents belt damage, bucket breakage, and motor overspeed.

Fan Drives
Provides backstop protection for induced draft (ID) fans and forced draft (FD) fans in power plants and industrial processes. Prevents reverse windmilling during shutdown.

Feeders and Pumps
Eliminates reverse rotation on apron feeders, screw feeders, and centrifugal pumps that must maintain one-way flow.

General Industrial Applications
The SLH series is also suitable for stamping presses, indexing tables, and any equipment requiring a reliable holdback function.

Sizes 1051 through 5000 cover a wide range of shaft diameters and torque requirements. Contact us with your application details for sizing assistance.

FAQs: SLH Series Holdback Clutch – Sizes 1051 to 5000

Q1: What is the difference between a holdback clutch and a standard overrunning clutch?

A: A holdback clutch (like SLH series) is specifically designed for low-speed, high-torque backstopping applications. It is optimized to prevent reverse rotation on conveyor head shafts and elevator drives. Standard overrunning clutches are often used for high-speed freewheeling or indexing. The SLH series is not intended for high overrunning speeds.

Q2: Can the SLH series replace a Formsprag or Marland holdback clutch?

A: Yes. The SLH series sizes 1051 to 5000 are designed to be dimensionally interchangeable with major brand holdback clutches. Please send us your existing model number or mounting dimensions for cross-reference and drawing verification.

Q3: What torque capacity does each SLH size have?

A: A complete technical data sheet is available upon request. Torque capacity varies by size and configuration. For accurate sizing, please provide your shaft diameter, required holdback torque, and speed. We will recommend the correct size within 24 hours.

Q4: Are SLH clutches grease-lubricated or oil-lubricated?

A: Both options are available. Grease lubrication is standard for general backstopping applications, especially where maintenance access is difficult. Oil lubrication can be specified for applications that already have oil bath systems.

Q5: What is the maximum shaft speed for SLH series?

A: The SLH series is designed for low-speed backstopping. Typical maximum shaft speed is under 300 rpm. For high-speed overrunning applications, please consider our DC series (up to 8,600 rpm) or RIZ/RINZ series.

Q6: Do you offer enhanced sealing for dusty or wet environments?

A: Yes. Large SLH sizes are available with enhanced sealing options to exclude dust, water, and contaminants. Please specify your environmental conditions when inquiring.

Q7: What is your lead time for SLH size 3000 or 4000?

A: Suma is a factory direct manufacturer. Standard SLH sizes typically ship within 20-25 working days. Larger sizes or custom configurations may require 4-6 weeks. Contact us with your specific size and quantity for current lead time.

Q8: Do you offer custom bores or mounting configurations?

A: Yes. We offer OEM/ODM customization for bore size, keyway, mounting flanges, and special coatings. Minimum order quantity may apply. Please provide your shaft drawing and requirements.