Patent GB-437609-A (GB)
Title: Improvements in or relating to striking and chiming gear for clocks
IPC: G04C21/08
Filed: 1934-05-01
Abstract: 437,609. Clocks. BROWN, T. A., 53, Swinderby Road, Wembley, Middlesex. May 1, 1934, No. 13083. [Class 139] Striking and chiming mechanism of the rack type includes a constantly rotating shaft 44 (e.g. of the time train) which drives the rack 70, or 34, through differential mechanism of which one sunwheel 40 is constantly driven by shaft 44, a second sun-wheel 41 is operatively connected to the rack (through parts 70, 82, 80, 81, 90, 34 in the case of rack 34), and the two sun-wheels are connected by planet-wheels 46, 47 on planet carrier 42 so that when the time train frees a release lever 30, the latter in turn releases a locking lever 26 which falls and locks the planet carrier 42 (pin 27) so that the second sun-wheel 41 is now driven from the first sun-wheel 40 and actuates the striking &c. mechanisms. The hour snail 14 rigid with hour-hand sleeve 16 and disc 18 rigid with minute-hand arbor 20, rotate clockwise, Fig. 1. This disc carries on one side a striking-release pin 22 and three additional chiming release pins 122 and on the other side a resetting pin 24 and three resetting pins 124. Locking lever 26 pivoted at 126 has a pin 27 which, for striking and chiming, locks the planet carrier 42 of the differential, which latter consists of carrier 42 carrying two intermeshed pinions 46, 47, of driving sun-wheel 40 fixed to shaft 44 and meshing with pinion 46, and of driven sun-wheel 41 which meshes with pinion 47 and is adapted to drive the striking rack 34, 49 as follows. After chiming, the chimes lever 70 rigid with sun-wheel 41 continues to move and meets a pin 82 on a lever 80. Since teeth 81 on this lever 80 are now engaged by a pawl 90 on the hour-striking rack 34, the latter is driven counterclockwise, Fig. 1, to strike the hours. Shaft 44 is driven continuously from the time train, but may be driven independently by a constantly running synchronous electric motor. Striking mechanism.-At about three minutes to the hour, the pin 22 on disc 18 lifts a nib 32 on a release lever 30 pivoted at 130, whereby the latter lifts its pin 33 out of slot 50 in the end of the striking rack lever 34. The latter rotates clockwise, Fig. 1, about the shaft 44 until its pin 52 meets the step of hour snail 14 which is opposite to it and corresponds to the hour. Lever 30 continues to rise until pin 22 clears the nib 32 whereupon the lever falls suddenly and hits a catch 36, which is rocked counterclockwise about its pivot 136 so that its shoulder 37 is removed from lug 38 on the locking lever 26. The latter thereupon falls so that its pin 27 locks in the teeth at the edge of planet-carrier 42. Whilst carrier 42 is free, sun-wheel 41 is stationary, but as soon as the carrier is held by pin 27, wheel 41 rotates counterclockwise, Fig. 1, at the same speed as the driven sun-wheel 40. Pivoted at 57 to the locking lever 26, of which the right-hand end has now fallen, is an interposer 56. As the differential gear restores rack 49 upwards, each tooth coacts with the left-hand end of a lever 60, 61 so that the latter is rocked and oscillates a bell-crank 55 which, through the interposer 56, closes the contacts 59, 60 of the electric hammer striking device, once for each tooth of rack 49 which passes the end of lever 60, 61. Mechanically-operated hammers may, however, be used. After the last tooth of rack 48 has acted, lever 34 continues to rock counterclockwise and its left-hand end rocks a catch 95, 64 to release a pin 66 on a resetting lever 28 pivoted at 128. Pin 29 on lever 28 in falling, rocks the locking lever 26 so that interposer 56 and pin 27 are raised and lug 38 is locked up on catch 37. Just prior to this, pin 33 drops into notch 50 to hold the rack lever 34. At about seven minutes past the hour the resetting lever 28 is itself reset by pin 24 on disc 18 which pin depresses the end 31 of lever 28 and causes pin 66 to lock up on catch 64. Chiming mechanism is driven through the same differential gear as the striking mechanism. The three chime release pins 122 are radially nearer the sleeve 16 than the pin 22 so that, for the quarters, the release lever 30 can be lifted by a pin 122 and nib 32 to release the chiming mechanism without pin 33 leaving slot 50 whereby the striking rack is not released. When pin 33 is thus partially raised, it releases a shoulder 94 on the chimes lever 70 which is rigid with the driven sun-wheel 41 and has four sets of chiming teeth 72. Lever 70 rocks clockwise, Fig. 1, until its pin 78 meets the chimes snail 76 fast on the minute arbor 20. When the pin 122 wipes free of nib 32, lever 30 drops and through catch 36 releases the lever 26 as in striking so that pin 27 locks the planet carrier 42. The differential thereby restores the chimes rack 70 counterclockwise. Each set of chiming teeth 72 actuates levers and contacts of chiming means similar to the levers 60, 61 and 55 and contacts 59, 60 used for striking above. To compensate for the varying relative angular positions of the striking and chiming rack levers 34 and 70 on account of the varying hours, a lever 80 is used having a rack 81 which coacts with a pawl 90 pivoted on the hour-striking rack 49. At an hour only, when pin 33 leaves slot 50, this pin rocks a detent lever 84 about its pivot 85 so that its shoulder 89 releases the pin 82 on lever 80 and allows this compensating mechanism to come into action. When no provision is made for quarter-chiming, the hour-striking rack lever 34 coacts directly with catch 64 to release the resetting lever 28 after the hour has been struck.