HFB & VFB Series | Formsprag Clutch

Horizontal Fan Backstops/Vertical Fan Backstops

Models HFB and VFB are backstopping clutching designed to prevent reverse rotation of shafts in applications that have large shaft diameters of up to 6.0 inches and low backstopping torque requirements. HFB & VFB backstops have Sprag clutch technology with high inner race overrunning speed, are ball bearing supported and protected with integral lip seals. The clutch housing is prevented from rotating with a torque arm and is mounted on a stub shaft with a locking ring for easy mounting. Clutches are selected by shaft size and torque requirement.

Product Features

  • Wide speed range of 0 to 2,000 RPM
  • Wide bore range of 1 .0 to 6 .0 inches
  • Wide torque range of 248 to 483 lb .ft . (337 to 656 Nm)
  • Low drag torque of < 1.8 lb.in. (20 Ncm)
  • Easy to install, requiring only 1 .125 inches of shaft engagement
  • Lubricated for life – No regular maintenance required
  • Rough bore kits in stock
  • Stops wind milling automatically
  • Improves both motor and belt life
  • Compact design with less than 2 .0 inches beyond the shaft end
  • Lip sealed backstop for longer life in adverse atmospheres
  • Wide temperature operating range of -4°F (-20°C) to 212°F (+100°C)
  • Self Actuated – No power or utility required to operate
  • Shaft mounting design tested to over 200% • Patent Pending
  • Removable torque arm
  • Optional coating available
  • No shaft keyseat required for mounting
  • Easy installation with a (1) clamping bolt design

Product Data Sheets

  • p-956-fc_hfb_vfb
Click on image below to download pdf. To order hard copies of literature click here.

Product Catalog

  • Overrunning, Indexing, Backstopping Clutches

Service Manual

  • Fan Backstop Clutches Models HFB & VFB Installation Instructions

Product News

Contact Info

Formsprag Clutch
23601 Hoover Rd.
Warren, MI 48089 - USA
Toll Free: 1-800-348-0881 (Press #1)
Phone: 586-758-5000
Fax: 586-758-5204

HFB and VFB Backstops
We are now a part of Regal Rexnord.
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