Patent GB-191312432-A (GB)
Title: Improved Method of Synchronising Clocks.
Inventor: BARTRUM CLEMENT OSBORN
IPC: G04C11/00
Filed: 1913-05-28
Granted: 1914-08-28
Abstract: 12,432. Bartrum, C. O. May 28. Pendulums and balances, regulating electrically.- Relates to apparatus for regulating a pendulum by means of periodic time-signals transmitted from a master-clock or the like, of the kind in which means are provided for automatically increasing or diminishing the rate of the p ndulum according to whether its error is negative or positive when the time-signal is received. If each change of rate is proportional to the error, both rate and error continually oscillate on either side of zero, and the object of the invention is to obviate this disadvantage by providing that the first change of rate imparted after the sign of the error has changed is greater than the subsequent changes of rate impar'ed while the error remains of the same sign. In the arrangement shown, the pendulum 26, Fig. 4, is connected to a short auxiliary pendulum 27, light springs 31, 32 being attached as shown. The period of vibration of the pendulum depends upon the tension of these springs. Cords 17, 23 are connected to the springs, and pass downwards to the device shown in Fig. 3. This comprises a wheel 15 and pulley 16 mounted on an arbor 19. An arm 20, arranged between stops 21, 22 is friction-tight on the arbor, the cord 23 being attached to the arm, and the cord 17 being wound around the pulley. The armatures of electromagnets 9, 10 are adapted to drive the wheel 15 in opposite directions by engagement with pins upon one of its faces. Connected by leads a, b, c, d to the magnets 9, 10 is a commutator-relay of known type, Fig. 2. It comprises an electro-magnet 3, to which the time-signals are transmitted, its armature bearing three contact-springs 5, adapted to engage with the surface of a drum 1, driven at a rate determined by the pendulum 26. The surface of the drum 1 has a conducting portion 2, as shown. When the magnet 3 is energized by a current constituting the time-signal, the attraction of its armature presses the contacts 5 upon the drum, and according to the position of the drum, depending on whether the pendulum 26 is fast or slow, a current passes to one or other of the magnets 9, 10, and the wheel 15 turns in one direction or the other. At each movement of the wheel in either direction, the spring 31, Fig. 4, is either stretched or relaxed by means of the cord 17, but whenever the direction of rotation of the wheel is reversed (on account of a change in sign of the error of the pendulum) the first step produces an alteration in the tension of the spring 32 also, brought about by means of the arm 20 and cord 23. Subsequent movements of the wheel, until its direction of rotation is again reversed, produce no further effect on the spring 32, owing to the arm 20 being blocked by one of the stops 21, 22. In a modification, movable weights may be substituted for the springs 31, 32. According to an arrangement described in the Provisional Specification, the additional changes of rate are brought about by means of auxiliary electro-magnets. The invention is stated to be applicable to balances.