Patent GB-227695-A (GB)
Title: Improvements in combined electric temperature-regulating and time-switch apparatus
IPC: G05D23/275
Filed: 1924-05-07
Abstract: 227,695. Matter, E. May 7, 1924. Thermostats.-Relates to temperature-regulating mechanism for electrically-heated apparatus of the kind in which a thermostat is combined with a time switch operated by clockwork for cutting off the current supply at predetermined times, e.g. during particular hours of the day, independently )f the operation of the thermostat, and consists in the particular construction of the combined apparatus including a motor-wound clockwork, a time switch and switch for the heating-circuit. The heating current is supplied from contacts 4, 5, 6 connected to the supply terminals 1, 2, 3 by a rotary switch E mounted on a shaft A<1> controlled by a motor A, the shaft A<1> also carrying a drum C with a conducting surface on which rest three contact arms F, G, H, one. H, of which is always in contact with the drum and is associated with the supply terminal 2, while the contact arm F is connected to the maximum temperature contact 7 of the thermostat and the contact arm G is connected through the time switch O, Q with the minimum temperature contact 8. Insulated strips D in the drum C maintain the arms F, G alternately out of contact with the drum. The circuit between the terminals 1, 2 is completed through the motor A and contact 9 of the thermostat. The rotary time switch comprises a brush O connected to the contact 8, contacts P, Q respectively connected to the contact arms F, G and a star-shaped member N which is actuated at predetermined time intervals by projections L on a dial J. When the time switch is in the operative position shown at the right-hand side with the brush O and contact Q connected, the switch E is controlled by the thermostat Z<1> to keep the temperature within the predetermined maximum and minimum limits. Thus, if the moving arm of the thermostat makes contact at 7, the motor A is started, causing the, switches E and C, F to be opened, thus interrupting the heating and motor circuits and the switch C, G to be closed; when the temperature falls again and contact is made at 8, the motor circuit is closed, the switch C, G opened, and the switches E and C, F closed, thus restoring the heating circuits. An indicator W, X shows whether the switch E is in the open or closed position. The dial J is constantly rotated by means of clookworks I, U, the springs of which are wound by a motor B connected between the terminals 1, 2 in series with a switch T which is alternately opened and closed by giving the shaft R of the clockwork U an axial movement by providing one end of the shaft with a fine screw thread engaging an internal thread on a pinion Z. When the motor B is winding up the clockwork springs a driving-pin S on the other end of the shaft R approaches and finally engages one of a series of studs on the switch T and rotates it to break the motor circuit. The springs then unwind until the driving pin S is disengaged from the studs, when a spring restores the switch to its closed position and, the motor circuit being again closed, the springs are re-wound.