Patent GB-191400066-A (GB)
Title: Improvements in and relating to Electrical Apparatus for Imparting Intermittent Motion at Predetermined Intervals.
Inventor: BANFIELD ARTHUR CLIVE
IPC: G04C11/00
Filed: 1914-01-01
Granted: 1914-08-13
Abstract: 66. Banfield, A. C. Jan. 1. Electric clocks.-Relates to secondary clocks, such as turret-clocks, in which a step by step movement of the hands is effected by means of an electromotor put into and out of circuit periodically by a rotary control-device, acting in conjunction with an electro-magnet. The invention also comprises improvements particularly applicable to time-recording apparatus, means being provided in this case for accelerating the apparatus as desired in relation to the controlling-clock. The electromotor 10 is geared to a wheel or pulley 4, keyed on a spindle 3 from which the hands are driven. Adjustably clamped upon the spindle 3 is an arm 11 carrying a bar 12 adapted to connect two contact-springs 13, 14 which are in the circuit of an electro-magnet 21. The armature 20 of this magnet has a bent arm 29, the end of which lies within an oil-bath 26, so that, when the armature is attracted, the arm is embraced by a forked contact 27, also immersed in the oil. The armature is further provided with one or more pins 17, normally resting on the periphery of the wheel 4, and, when the wheel is at rest, engaging in one or more slots 16, Fig. 4, therein. The electrical connexions are shown in Fig. 1, in which 50 represents a source of current (one pole being earthed), and 51 an earth connexion through which the field magnet of the motor may be permanently excited. When the magnet 21 is energized by the closing of clock-actuated contacts, such as 57, its armature is attracted, the pins 17 are withdrawn from the wheel 4, and the contacts 27 are earthed through the arm 29. This starts the motor 10, and the wheel 4 rotates. The circuit of the electromagnet is at once broken by the movement of the arm 11, so that sparking cannot occur at the clockactuated contacts 57 &c. when they are opened. The armature of the magnet 21 is no longer attracted, but since the pins 17 rest on the edge of the wheel 4, the contacts 27, 29 remain closed until, after a complete revolution of the wheel, the pins 17 enter the slots 16. The armature then moves forward, opening the contacts 27, 29 so that the motor stops. One revolution of the wheel 4 thus occurs at each successive closure of the contacts 57 &c. A number of slots 16 may, however, be provided at different points of the periphery of the wheel, together with a corresponding number of contact devices 12 &c., so that the wheel makes only a fraction of a revolution at each step. In connexion with time-recording apparatus or the like, the rotary clock-driven switch may be provided with several sets of contacts 57, 58, 59. The number of contacts in each set is so chosen that each set is adapted to close the circuit of the electro-magnet 21 a different number of times in a given period. The effect of this is that the timerecorder may be accelerated in relation to the controlling-clock, according to the number of contacts in the particular set chosen to control the apparatus. For example, the sets 57, 58, 59 may close the circuit 100, 125, and 150 times per hour respectively. This provides that the time-recorder may indicate either normal time, or 'time and a quarter,' or 'time and a half.' A selective switch 30, Figs. 1 and 3, enables the chosen set of contacts to be brought into action. It comprises a set of insulated contact-fingers 32, 34, 36, and oppositely-disposed insulated fingers 33, 35, 37, connected together. Any pair of opposing fingers can be bridged by a metal stud 40, mounted in an insulating-disk carried by a slidable rod 38. The rod extends through a slotted sleeve 41 and has an arm 42 which may be turned down into any one of the slots so that the rod may be fixed with the contact-stud 40 in a selected position. In the position shown, the sets of contacts 58, 59 are inoperative. Counting-devices 60 may be arranged in circuit as shown in Fig. 1, to indicate the number of times the apparatus is actuated.