Patent GB-987231-A (GB)
Title: Electronic clock
Inventor: ANDERSON ROBERT DEAN
IPC: G04G9/04
Filed: 1961-02-07
Abstract: 987,231. Clocks. SUNBEAM CORPORATION. Feb. 7,1961, No. 4608/ 61. Heading G3T. [Also in Division H1] An electronic clock includes a first gaseous discharge means for sequentially producing a glow discharge at spaced points within a first annular space within a gas-filled housing at a rate of one glow discharge per minute, and second gaseous discharge means for sequentially producing a flow discharge at spaced points within a second annular space within the housing at the rate of one glow discharge per hour, the annular spaces being concentric. The arrangement shown in Figs. 1 and 2 comprises a central disc anode 20,a series of twelve glow cathodes 22a-22b corresponding to the hours, and a pair of guide cathodes, or transfer electrodes, 23a and 24a interposed between each pair of the glow cathodes. For displaying the minutes there are provided an anode 30 in the form of a circular band, sixty glow cathodes 31,and a pair of guide or transfer electrodes 32,33 positioned between each pair of the glow cathodes 31. Indicia are provided to identify the hour and minute glow cathodes. For displaying the seconds there are provided an anode 40 in the form of a circular band, sixty glow cathodes 41,and a pair of guide or transfer electrodes 42,43 between each pair of the glow cathodes 41. Indicia can be provided to identify the glow cathodes 41. In order to produce suitable control pulses for supply to the transfer electrodes 42, 43 to effect energization of the glow cathodes 41 at the desired second intervals an arrangement is provided to reduce the frequency of the conventional 60 cycle A.C. by a factor of sixty. This arrangement includes an anode 50 in the form of a circular band, sixty glow cathodes 51,and a pair of guide or transfer electrodes 52, 53 between each pair of the glow cathodes 51. The glow cathodes 51 are energized at the rate of one every sixtieth of a second and may be masked by an opaque shield 60. The glow cathodes corresponding to the hours and minutes can be set by an arrangement which causes these cathodes to be energized every second. The glow cathodes and transfer electrodes can be in the form of pins provided with head portions. The glow cathodes corresponding to the hours can be of wire in the shape of numerals,a silk screen type of printed conductive material being provided on a ceramic base and the anode 20 being suitably shaped. The space 13 of the housing 10 is filled with neon at a low pressure. In a modification only one transfer electrode is provided for each glow cathode, the transfer electrodes being so shaped and positioned relatively to the anode as to favour glow discharge transfer in a particular direction or a magnetic field may be established so as to cause the transfer of glow discharge in a particular direction. In a further modification a common anode in the form of an edge-mounted circular band is used for the hours' and minutes' electrode rings. In the construction of Fig. 1 and 2 the outermost rings 41 and 51 may be eliminated and control pulses occurring at one minute intervals can be derived from a separate electronic counter. An integrating circuit, positioned in the housing 10, is described to provide two separate transfer pulses from a single control pulse derived from the A.C. supply or a preceding glow discharge ring, the two transfer pulses being sequentially impressed upon respective transfer buses of the glow discharge ring to effect glow transfer. In a modified circuit essentially square wave pulses are provided for the transfer electrodes and it is arranged that the second transfer pulse starts coincident with the trailing edge of the first transfer pulse. In a further circuit separate electronic counter arrangements are provided to establish the control pulses for seconds', minutes' and hours' glow discharge rings,the counting arrangements being independent of the glow discharge display device itself. This circuit can use magnetic cores and transistor arrangements but other arrangements of transistor or vacuum tube circuits, such as bi-stable multivibrators or flip-flop circuits, may be employed together with the necessary logic circuits to provide the required pulse division by factors of 60. For example, a set of three beam switching tubes can be used to divide the input pulse rate by five,four,and three, respectively, a coincidence circuit being used to develop an output pulse divided by a factor of sixty from the outputs of the three tubes.