Thursday, 4 May 2017

The Lancashire Watch Co / Samuel "Trip Action" movement.

A common LWC full plate movement was known as "The Dummy" referring to a Dummy Fusee wheel / pinion that converted the movement to wind anti-clockwise in the manner of an English Fusee watch. This is the movement commonly found in the popular Graves "English Express Lever".

These movements also have a "Safety Pinion" to protect the workings in the event of a mainspring breaking or suddenly winding down, perhaps due to the click failing.

There is an uncommon variant of this design which I have only seen in watches branded by Harriet Samuel of Manchester. It has a patented device which combines the functionality of both the dummy Fusee and the Safety Pinion. They call it their Patented "Trip Action", it is not clear to me who held the patent, Platt [1] records this variant, also in movements for Samuel, and states that the "Trip" action in the watch is not quite the same as in the patent but similar too it but he does not name the patent holder.

The large dummy Fusee is replaced with a smaller pinion mounted on a swinging arm that is held in place by being pressed against a toothed rack. In normal use this connects the main-spring barrel to the centre wheel pinion. If the spring fails with any force the back-lash causes the pinion to fly away from the centre wheel protecting the train. It can later be reset by pushing it back into position.

[1] Lancashire Watch Company, History and Watches, John G. Platt, Inbeat Publications, 2016 p 281.

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