Patent GB-283167-A (GB)
Title: Improvements in or relating to electric clocks
IPC: G04C3/02
Filed: 1927-03-12
Abstract: 283,167. Poole Manufacturing Co., Inc., (Assignees of Poole, A. F.). Jan. 6, 1927, [Convention date]. Electric clocks; cases, clock. -In an electric clock the pendulum and its crutch directly drive ratchet mechanism operating the motion work, an impulse being given to the pendulum by a weighted lever when the oscillations fall below a predetermined minimum; the weighted bar is released by Hipp contacts and raised electromagnetically. A base 1, Fig. 1, supports a column 3 which contains the battery and carries magnets 20, 21 and the dial mechanism 30 coacting with the pendulum 43. The column 3 is set in a hole 4, Fig. 6, in the base and is held in position by a ridge 5, a plate 7 in the bottom of the column, and screws 9 which pass through a plate 8 and thread into the plate 7. A spring 13 supports the battery 10 so that the upper terminal 11, Fig. 5, presses against a contact blade 17 set on the cap 12. This cap has a tongue 14 catching into a hole 15 in the column and the end 18 of the blade 17 has snapped over it a contact blade 19. The entire device is enclosed by a transparent dome 2, Fig. 1. Two electromagnets 20, 21, Figs. 5, 6, and 22, are attached to the column 3 by a strap 23, a bar 22 of magnetic material, and bolts 24, filler blocks 27 being used, and the magnet cores, being fixed to the bar 22. Mounted on the frame 29 are motion wheels 28, Fig. 5, driven from a ratchet wheel 37, Fig. 10, which is operated by a pawl 52. Figs. 4 and 10, carried on the crutch 44 which has a fork 46 embracing the pendulum 43 suspended on a flexible member 41. The pawl 52 is mounted in a groove in a shaft 48, the edges of the groove being burred over to grip the pawl firmly. An impulse pin 63 on the crutch 44 is adapted periodically to receive an impulse from a roller 62 mounted on a weighted lever 59 pivoted at 60 to the clock frame. The roller 62 is mounted between the lever 59 and an arm 61 of the latter extending parallel thereto. An armature 64 of the magnets 20, 21, Fig. 1, is composed of several parallel plates spaced apart by studs 66, the outer plates having arms 67 and the armature having pivoting studs 65. Between the arms 67 is a shaft 68 carrying a bellcrank 69, a nose 70 of which normally latches under an ear 71 on the lever 59. Springs 78, Fig. 5, act upon the armature so as to retract it to the position of Fig. 7, whereby the nose 70 maintains the weighted lever 59 raised. One of the pivot studs 65 is surrounded by a friction strap 79 subject to a spring 80 to damp minor oscillations of the armature. A lateral extension 81 on the bell-crank 69 bears against a lever 82 which is pivoted at 68 and bears against a pin 83, Fig. 10, on a lever 84. This lever 84 is pivoted at 85 and at its free end has freely pivoted on it a member 87 having a notch 90 between a long and a short tooth 88, 89. The notch 90, Fig. 13, coacts with a lug 91 on an arm 92 of the crutch 44 in the usual manner of Hipp contact mechanism. When the lever 59 falls a contact screw 94 thereon meets a contact stud 95 and completes the circuit of the magnets 20, 21. Thus when the amplitude of the pendulum falls below a certain minimum the lug 91 fails to clear the member 87 and, lodging in the notch 90, raises the lever 84 ; this, through the pin 83, rotating levers 82 and 69 counterclockwise, Fig. 10, so that the nose 70 releases the projection 71. The lever 59 thereby falls and gives an impulse to the pin 63 and the pendulum, and completes the magnet circuit at 94, 95. The armature 64 is attracted, compressing a spring 112, Fig. 7, and drawing the nose 70 down to latch under the lowered lug 71. The rebound given to the armature by the spring 112 is sufficient to cause the bell-crank 69 to raise the lug 71 and lever 59 sufficiently to break the circuit at 94, 95. This de-energizes the magnets, the armature returns to the position of Fig. 7 by reason of the springs 78 and the lever 59 is fully raised until the amplitude of the pendulum again falls to the minimum. A spring 113 on the lever 59 may also be used with a lug 64<a> on the armature to give the rebound to the armature.