Jaw Flexible

Flexible Jaw Coupling

Key Features

  • Curved jaw design
  • Torque ratings from 10Nm to 3300Nm
  • No need for lubrication
  • Quick and simple to install
  • Reliable, rugged and compact
  • 4 Standard spider types available
  • Elastomeric element resistant to heat (-40°C+90°C), grease, oil and chemical agents
  • Hubs in aluminium and sintered iron
  • Full-Flex and Flex-Rigid design available

Steel Gear Flexible Coupling

Continuous Sleeve Steel Gear Coupling
Flange Sleeve Steel Couling

Key Features

  • High transmittable torque ratings
  • Vari-crown tooth form for improved torque transmission and longer life
  • Strong compact design
  • Low inertia and high maximum speeds
  • Spacer couplings available on request
  • Full-Flex and Flex-Rigid design available

Flexible Spacer Coupling

Flexible Spacing Coupling

Key Features

  • Self-Supporting Drive Shaft, know as Spacer Coupling
  • Torque Ratings from 32Nm to 1000Nm
  • Compact, light, robust, safe operation, long life
  • Two identical hubs and one flexible elastomeric element at each end
  • Hubs of high tensile steel
  • Large permissible bores, various hub lengths
  • Driving dogs have smooth surface, high durability
  • Damps vibrations and shocks, compensates for axial, radial and angular misalignment

Drive Shaft - Standard

Standard Drive shafts

Key Features

  • Machined journals and keyways at each end
  • Keys supplied for each end
  • Standard diameters of 20mm, 30mm, 40mm
  • Other diameters available on request.
  • Up to 5m lengths available as standard
  • Steel or Stainless Steel designs available
  • These shafts require bearing support

Useful Information

The selection of coupling type depends on the installation and the type of misalignment. The three main types of misalignment encountered are:-

  • Angular Misalignment is usually present to some extent on all applications, typical values 1° - 2°. Sometimes higher values are necessary
  • Parallel (Radial) Misalignment is also nearly always present. A well aligned installation might have values below 0.25 mm
  • Axial Misalignment (End Float) sometimes caused by thermal expansion or as a result of machine design

Other considerations include:

  • Backlash Free Couplings are either one part couplings or have bolted joints. These are effective for precise positioning and to avoid wear on reversing drives.
  • Torsional rigidity of couplings depends on the joining method. Types with rubber or plastic elements can be considered as torsionally soft and will have an amount of twist at rated torque.


  • Decide if the coupling should be torsionally soft or rigid.
  • Consider whether a small amount of backlash is acceptable.
  • Calculate the required coupling torque.
  • Make a provisional selection.
  • Check that the coupling’s maximum speed is sufficient.
  • Check that the coupling’s dimensions are acceptable.

Contact Power Jacks with your order or technical enquiry

Select Drive Shaft Diameter
Select a standard drive shaft from the drive shaft table and check its torque rating and angle of twist rating against the application requirements.

If Transmitted Torque (Nm) < Maximum Drive Shaft Torque (Nm) & If Acceptable Angle of Twist (Deg.) for shaft length < Rated Angle of Twist for Drive Shaft (Deg.) then drive shaft diameter selected is acceptable.

Check Drive Shaft Critical Speed
For the unsupported shaft length calculate the drive shaft critical speed for the support conditions required.

If Shaft Speed (rpm) < Drive Shaft Critical Speed (rpm) then drive shaft selection and configuration is acceptable.

  • Maximum misalignment values are extremes and should not be combined. As operating misalignment approaches the maximum, torque and power ratings should be reduced to maintain life
  • The maximum axial misalignment values apply when the coupling is aligned. If axial misalignment greater than the listed maximum is required, consult Power Jacks
  • The inertia values includes shafts through the bores
  • When ordering please quote the coupling size and type, specify the bore and keyway sizes, and advise if puller holes or set-screws are required
  • For maximum performance the screw jacks, actuators, gearboxes, motors and shafts should be carefully aligned
  • Imperial (Inch) couplings on request


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Couplings & Drive Shafts(EN)