Patent GB-270635-A (GB)
Title: Improvements in and relating to clocks
IPC: G04B21/02
Filed: 1926-12-21
Abstract: 270,635. Mazur, S. May 10, 1926, [Convention date]. Chimes; striking-mechanism. - Quarter chiming mechanism and hour striking mechanism are operated by a single common spring, means being provided for bringing under its operation at the appropriate time the chiming mechanism, or the striking mechanism, or both. The ordinary time movement with its spring 30 for driving the hands 27. 29 is between plates 20. 21, and the main portion of the chiming and striking mechanisms is between the rear plate 21 and an auxiliary plate 24; 26 is the hour hand shaft and 28 the minute hand shaft. For controlling the chiming and striking mechanism, this shaft 28 carries an axial cam 47, a star-wheel having four-teeth 48 - - 51. and a gear-wheel which drives a wheel 55 rigid with the chiming cam 53. The striking cam 52 is on the hour shaft 26. A spring 57. which is common to the chiming and striking mechanisms, drives shafts 56 and 69 through gearing which includes the braking fly device 68. Normally the shaft 69, and, therefore, the spring 57 are arrested by a notched disc 70 on shaft 69, Fig. 11, being held by a finger 72 on an arm 71 which is rigid with a shaft and an arm 75, 76. Engaging under finger 76 is an arm 78, Fig. 10, on a shaft 77 which carries an arm 79 having a lug 80 which is actuated by the star wheel 48 - - 51. Thus at each quarter hour the appropriate tooth of the star-wheel moves the parts 80, 77, 78, 76, 71, 72 and releases the disc 70 and shaft 69. At first, however, the shaft 69 only turns slightly to put the chiming mechanism in a warning or preliminary position. For this a pin 81 on the gear train of the shaft 69 is engaged by an arm 82 rigid with the arm 79. When the star wheel clears the lug 80 the various parts are returned and the finger 72 and arm 82 are relowered. The finger is now out of register with a notch and pin 81 is free, so that the shaft 69 turns until the next notch reaches the finger 72. Since one or more complete rotations of the disc 70 may be necessary to effect the required number of chimes and hour strikes, the finger 72 may be withheld from the disc 70 by an arm 83 on the shaft 77, coacting with a detent arm 84 which is only returned to normal to re-lower the finger 72 when the correct chiming &c. has been effected. Slidable on the shaft 56 driven from the spring 57 is a chime drum 94 having four annular rows of pins 97 - - 100, and also slidable on this shaft is a striking disc 101 having pins 201. A pin 103, Fig. 5, rigid with the shaft 56 is always engaged in a hole 102 in the disc 101, and, when a bell-crank 110. 111 is rocked by a cam 47 on the minute-hand shaft, the chime drum 94 is moved rearwardly so that the pin 103 is also projected into one of a number of holes 204 in the drum. This drum is normally locked by a stationary pin 105, but is released therefrom when moved rearwardly, and, on rotating, can only move into locking position again after a complete revolution when the pin 105 again registers with its hole in the drum. The pins 97 - - 101 coact with levers 112 - - 116 having pins 118 which operate hammer levers 119 - - 122 with hammers 125 for striking the tune rods 126. One of these tune rods is also employed for striking the hours. When the chime drum is moved rearwardly the striking disc also moves so that as the chiming pins come into operative relation with their levers 112 &c. the striking pins are moved clear of the corresponding lever and only come back into position after chiming has been completed and the chiming drum has again returned forwards. Two ratchet sectors 130, 131 coact with pawl faces 240 ,140 respectively, Figs. 14 and 18, on the detent arm 84; the main sector 130 has just over twelve teeth and the auxiliary sector 13 has just over four teeth. Sector 130 has an arm 136 and finger 187 engaging the striking cam 52, and the sector 131 has an arm 138 and finger 139 engaging the chiming cam 53. The shaft 69 carries a lifter 141 comprising teeth 142, 143, Fig. 11 which engage the teeth or the main and auxiliary sectors respectively. At the end of the first quarter hour the tooth 48 of the star wheel moves the lug 80, Fig. 10, and releases the shaft 69 and also moves the arm 84 so that pawl 140 is moved away from under rack 131, but pawl 240 still engages under rack 130: so that the rack 131 drops until the finger 139 reaches the first step of the chiming cam 53; at the same time the shaft 56 rotates and the lifting device 141 rotates. The chiming drum rotates to cause four strokes on the tune rods, the finger 71 reengages the notched disc 70, and the lifter raises the rack 131 the one tooth it has dropped so that the pawl 140 again engages under the lower end of the rack. As further quarter hours pass the chiming is increased as the finger 139 falls further on to the successively lower steps of the chiming cam, the lifter afterwards returning the rack upwards tooth by tooth. At the end of an hour the long tooth 51 of the star wheel moves the arm 84 a large amount so that both pawl faces 140 240 are withdrawn and both racks 130, 131 come into play, bringing the striking cam as well as the chiming cam into operation.