Bevel Jack Multiple Jack Arrangments

Multiple Jack Arrangments

For multiple jack arrangements, total kilowatts required depends on horsepower per jack, number of jacks, the efficiency of the gear box(es) and the efficiency of the arrangement.

Arrangement efficiency –

  • Two jacks = 95%
  • Three jacks = 90%
  • Four jacks = 85%
  • Six to eight jacks = 80%

The efficiency of each miter gearbox is 90%. Therefore, motor kilowatts requirement for the arrangement:

where N = Number of gearboxes.

If the application duty cycle exceeds the allowable duty cycle as illustrated on pages 8 and 9 for the jack selected, several solutions are possible.

  • Use a larger jack model to increase the maximum allowable horsepower.
  • Use a Ball Screw Jack to reduce the power required to do the same work.
  • Operate at a lower input speed.
  • Use a right angle reducer to bring the power requirement within acceptable limits.

When utilizing multiple jack arrangements, the input torque to the first jack must be considered. It is recommended that the number of jacks driven through a single jack input be limited to a maximum of three jacks. Consult Nook Application Engineers for arrangements where more than three jacks will be driven through a single jack input.


The input shafts can either rotate CW or CCW with respect to extending the lift shaft. Care must be taken when using multiple jack arrangements. Bevel Jacks with two input shafts will rotate in opposing direction with respect to their common axis.

Image 1 - U Arrangment

Image 2 - H Arrangment

Image 3 - I Arrangment

Image 4 - T Arrangment

Figure 1