The Big Ben movement is based on the normal Western Clock Manufacturing Company alarm clock movement, with the several additions. It incorporates an intermittent alarm feature that is an improved version of the “repeating” alarm described in patent #855,775 issued June 4, 1907. The repeat feature can be turned on and off. The alarm train has three gears to give a long alarm ring time. The movement plates are larger, with four steel pillars for rigidity. The alarm hammer is articulated, haveing two pivot points and a linkage. The alarm trip spring pushes the repeat lever out of engagement with the repeat cam, except during the time the alarm is enabled to ring. This eliminates the drag of the repeat mechanism on the time train most of the time (about 10 1/2 out of every 12 hours). The patent shows the slider on the case which pushes the repeat lever out of engagement when the alarm is set to "Steady".
