Shaft Coupling

Notes

• Coupling is the most critical aspect of mechanics, and most failure occurs at the coupling.
• Keyways do not work [1]
• Clamps without keyway do not work. [2]
• Clamp couplers appear to be the best, but what is their limit?
  • We saw 3500 lb drive on 4" radius, or DIY clamps at about 14k in lb with LifeTrac v8 nut planting.

Calculations

• Coefficient of friction of steel is 0.2 [3]

Fastener Types

• Quarter Turn coupler - can be removed many times. [4]
• Huckbolt - clamp bolt that does not loosen - [5]. See dramatic loss of clamp using bolts.

More

File:Servocouplingguide.pdf

File:Helicalcouplings.pdf

This report discusses attributes of different types of shaft couplings used to transfer power from the engine shaft to the hydraulic pump.

Jaw Coupling

Please note that once a coupling is selected, special attention must be paid to the shaft keys. They must fit tightly, as any slack will eventually destroy the coupling.

File:CouplingDestroyedByKey.png

The jaw coupling is composed of three pieces:

• Two coupling halves, to connect to each of the two halves, with three piece jaws to transfer power and a spider insert to make soft connection between the two jaw halves:

Note: Experience has shown that this type of coupling does not work well with the Power Cube, as the spider insert fails after 40 to 100 hours of operation.

Solid Coupling

The solid coupling consists of a solid steel piece that connects to each of the two shafts and has set screws to secure the coupling to both shafts.

This is the currently preferred coupling and is used in new Power Cubes.

Double Roller Chain Coupling

The double roller chain coupling is composed of three pieces:

• Two pieces connecting to each of the two shafts
• A chain to transfer power between the two shaft couplings

This coupling looks promising, but has yet to be tested with the Power Cube.