Patent GB-191424637-A (GB)
Title: Improvements in or relating to Control-devices for Electric Clock Systems.
Inventor: HATTON GEORGE CUTHBERT
IPC: G04C13/04
Filed: 1914-12-24
Granted: 1915-09-23
Abstract: 24,637. Hatton, G. C. Dec. 24. Electric clocks.-In controlling-apparatus for an electric clock system, particularly applicable for ships, the alteration of the hands of the master clock effects a corresponding alteration of the hands of the secondary clocks. A ratchet-wheel E is freely mounted on the minute-hand spindle A of the master clock and is driven by a resilient pawl E<2> which receives a step-by-step motion in common with the auxiliary clocks. The electric current operating the pawls passes through a resilient finger F, a part D free to slide along the spindle A but rotated by the ratchet-wheel E, a resilient finger G<1> attached to the spindle A but insulated therefrom, and a contact finger H carried by, but insulated from, the frame F<1>. The part D is driven by a pin E<1> fixed to the ratchet-wheel E, and carries a tooth D' engaging a worm C fixed on the spindle A. The edge D' of the part D conforms to the pitch of the screw of the worm C and its ends are joined by a step d. In ordinary working, the spindle A has a continuous rotation, and the member D a step-bystep motion. The completion of the electric circuit, by which the motion of the pawl E<2> is effected, is made by the finger G<1> engaging the step d, which is then moved out of contact by the rotation of the ratchet-wheel E, only to be overtaken again, usually at half-minute intervals. When the hands of the master clock are set back, as shown in Fig. 1, where the setting-back amounts roughly to a quarter of an hour, the worm C, by engaging the tooth D<1>, moves the part D out of engagement with the finger G<1>. The hands of the auxiliary clocks thus remain stationary until overtaken by the master clock, whereupon the finger G<1> will again engage the step d. When the hands of the master clock are set forward, the part D will be drawn under the finger G', with which it will remain in contact until the hands of the secondary clocks overtake those of the master clock, whereupon the contact G<1>, D will be broken again after which the drive of the auxiliary clocks will continue every half-minute as usual. The step-by-step mechanism by which the pawl E' is operated comprises an electro-magnet J, Fig. 3, an armature J<1> controlled by a spring J<3> and carrying an arm J<5> to which the pawl E<2> is attached, and also a resilient arm J<4> engaging a pin K<4> on a disk K<3> mounted on a spindle K<1>. The current by which the magnet J is operated passes through the parts J<4>, K'. When the armature J<1> is attracted by the magnet J, the arm J<4> pushes away the pin K<4>, the contact is broken, and the pawl E<2> under the action of the spring J<3> rotates the ratchetwheel E. A spring K<5> brings the pin K' again into contact with the arm J<4>. A larger disk K' gives inertia to the spindle K<1>, and stops K<8> strike the frame K and prevent the apparatus from getting up too great a swing during a repeat action of the mechanism, such as is required when the hands of the master clock have been set forward. In a modification, suitable for controlling a turret clock by means of a master clock, where the turret clock is liable to vary with varying conditions, a pawl M', Fig. 4, is reciprocated from the pendulum of the turret clock and normally advances the toothed wheel M<1> two teeth at a time. If the turret clock gains, a cone N' moves to the right, by the action of a worm L<1> on a tooth N<2>, and reduces the time of contact of the pawl M<2> with the wheel M', and so causes the number of teeth operated to be reduced to one, or even none at all. The turret clock is thus retarded until the master clock overtakes it, and the cone N' at the same time is returned to its normal position. If the turret clock lags behind, the cone N<3> is moved to the left and the number of teeth operated by the pawl M<2> is increased.