The Music Train
Ronald R. Hoppes · Transactions of the American Philosophical Society · 2009
LKFTAND right views OF the music drum, hammers, and bells are shown in Figure 59. The fly, which governs the speed of the tune play, is visible on the rear of the movement in the right-hand view. Figure 60 is a photograph of the gearing, tune trip, tune repeat, and tune change components. Figure 61 is a line drawing of the music train and controls. The music section has a substantial number of settings to select from. These settings determine the characteristics of the tune-playing operation. They define how frequently a tune is to be played and the number of times a tune will be repeated before the performance is ended. lhe music train can be set to be silent or engaged automatically at one of four selected intervals, Silent, 2 hrs, 1 hr, ½, hr and ¼ hr. In addition, a tune can be set to be repeated 1, 2, 3, or 4 times each time the play sequence is initiated. The weight drops 0.1374447 for each play of a tune. So the weight drop per day will increase as tunes are played more frequently or the number of repeats for each play is increased. The intervals between windings for a repeat selection of one, are listed. The winding interval also becomes more frequent as the number of repeats is increased. Divide the winding intervals by the number of repeats selected per play. For two repeats divide the winding interval by 2, and by 3 for three repeats. Similarly for four repeats divide by 4, so if the '/+-hour play interval is selected along with 4 repeats per play, the winding interval is basically every day (4.5 days/4= 1.1 days). Play every 2 hrs. (12 plays per day) = 36 days Play every 1 hrs. (24 plays per day) = 18.1 days Play every ½ hrs. (48 plays per day) = 9 days Play every ¼ hrs. (96 plays per day) = 4.5 days Tunes may also be played at any time by the means of the Tune Repeat lever. Of course this also reduces the length of time between required windings. The gear train of the clock movement also drives the tune-change snail and tune indicator. The gear train causes the 10-tune snail to make one revolution in 40 hours, causing a tune change every 4 hours. So, starting with tune 1 on day 1, the tune sequence is: Day 1 the tunes are 1, 2, 3, 4. Day 2 the tunes are 5, 6, 7, 8. Day 3 the tunes are 9, 10, 1,2. Day 4 the tunes are 3, 4, 5, 6. Day 5 the tunes are 7, 8, 9, 10. Day 6 the tunes are 1, 2, 3, 4. We see that the tune sequence repeats on day 6. THE TRIP SEQUENCE The trip mechanism is illustrated in Figure 61. The figure illustrates the music train gearing and control levers. The gears that change the tune selection are not shown so as not to clutter the diagram, and will be described later. To better illustrate the operation of the play sequence, Figure 62 shows the first stage of the trip operation. It illustrates the pin on the trip wheel just as it makes contact with the trip pawl. Note that the toothed sector, which counts the number of tune repeats, is still in its most left-hand position. It is held in this position by the pin of the warning lever. This pin on the warning lever is shown as a solid dot in the figure. When the warning lever is lifted by the trip pawl, the sector falls to the right, influenced by the spring pushing against its curved tail below its pivot point. Figure 63 illustrates tip of the trip pawl ready to escape from the lifting action of the trip pawl. Note that the trip pawl has lifted the trip lever, which in turn has lifted the warning lever. Also note that the trip pawl has rotated slightly clockwise on its pivot screw during the lifting action of the trip pin. As soon as the trip pawl escapes, the leaf spring mounted above it causes the pawl to return to its previous position, which results in a small counterclockwise rotation. This action allows the tip of the trip pawl to pass over top of the pin and clear it, so that the trip pawl is free to fall back to its starting position. …