August 2007.

Taig Leadscrew Dog Clutch

We think of clutches as being smooth in operation, but a dog clutch describes a positive on-off device.

Essentialy this clutch is just a short length of sliding shaft (the dog), made semicircular in section at the ends. One end is more than twice the length of the other. The long end is always engaged with a matching half-shaft from the leadscrew - no matter how far you slide the dog within the confines of the box. However the short end is able to come undone from its mate on the gearbox, causing the disengagement.

For a much better and printable PDF version of this diagram CLICK HERE.

                                                                                                         Thanks ER !

Photos of the innards of the clutch on the leadscrew follow:

The entire unit slides off in one piece

(chunk of metal under the gearbox was a supporting prop for the photo)

Ball knob

Front plate (milled)

The fork threads through the slider and the ball screws on outside

Back view of the bronze fork

The dog itself

(stainless steel)

The leadscrew collar is pinned to the output shaft stub

Note the output shaft collar is entrapped between bronze for a thrust bearing

Dog (left) and output shaft

End bearing cap back edge

Main body showing dovetails

Dovetails in action

(note recessed thrust bearing for input shaft)

Complete taig leadscrew disconnect kit

The input shaft (pinned to the output gear)

(it also has a collar trapped by bronze on both sides for thrust bearing)

Together again....

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