Patent GB-122640-A (GB)
Title: Improvements in Electromagnetic Wave Signalling Arrangements.
Inventor: FRITZ LOWENSTEIN
IPC: H01T9/00
Filed: 1919-01-20
Abstract: 122,640. Lowenstein, F. Jan. 19, 1918, [Convention date]. Discharge-gap apparatus; electric oscillations, producing.-In multiple quenched spark-gap apparatus tor producing high-frequency oscillations by the condenser discharge system, the multiple gap is built up of a series of' readily removable and replaceable units, each unit comprising one or more pairs of disk electrodes with annular sparking-surfaces and sheet-metal cooling-fins. Switch mechanism is provided for varying the number of gaps in circuit in relatively large, and in small, steps. Fig. 1 is a side elevation, and Fig. 3 a plan, of one arrangement, a separated unit being shown in Fig. 6. Silver sparking-rings 22 are secured to the adjacent surfaces of disks 20<a>, 21<a> of brass or other metal. The disks are flanged as shown, and are secured to each other by a bronze stud 23<a>, which is screwed into one member and has a head bearing against a pressure 24<a>. An insulating-washer separates the pressure wa.sher 24<a> from the disk 21<a>, and an annular insulating- member 30 separates the two disks 20<a>, 21<a>. The pressure washer may be varied in shape or may be omitted. The stud passes through a large opening in the disk 21<a>, and the chamber in which the sparking takes place is air-tight. The cooling- fins are formed of rectangular sheets 31, preferably of copper, with circular openings to fit around the disks 20<a>, 21a, and with their vertical sides 33 flanged and overlapping, thus forming two or more narrow vertical tubes through which a draught of cooling-air will readily pass upwards. Sets of holes 311 in the cooling-sheets 31 enable the sheets to be correctly alined and also ensure that the insulator 30 is placed in the central position. The insulating-frame for supporting the sparking- units comprises a pair of end plates 35 connected by horizontal bars 36, 36<a>. Spaced along these bars are metal brackets 39 having pointed upper ends 40 and pairs of spring contact members 42 projecting downwards and in an inclined direction. When the gap units are removed, these contact members engage at their lower ends 44, and when a spark-gap unit is pushed downwards between the contacts, the cooling-fins 31 separate the spring members 42, thus putting the inserted unit in circuit. For varying the number of gaps in circuit in relatively large steps, a switching- arrangement is provided comprising a longitudinal shaft 54 operated between limit stops 'by a handle 56 and carrying three contact-arms 51, 52, 53 separated angularly and axially and arranged to make contact with projections 48 on the brackets 39. One terminal of the sparking-set is connected electrically to the shaft 54 so that all gaps to the right of the operative contact-arm 51, 52, or 53 are short-circuited. The arms are adjustable along the rod 54 and are locked by suitable detents. An auxiliary short-circuiting device giving a finer adjustment comprises a shaft 61 with angularly-displaced contact-arms 57 - - 60 placed opposite the successive units at the lefthand end of the set. The shaft 61 is in electric connexion with the terminal 49, and by placing any of the switch arms 57 in contact with the corresponding member 57<a>, the gaps to the left are short-circuited. The contact members 57 - - 60 have wide engaging faces in order that one may engage before the next one has disengaged. The frame supporting the gap units also carries a condenser 37 and a support 38 for the transmitter inductance coils. In a modified arrangement, spring clamps bearing frictionally on the shafts 61, 54 are connected respectively to the condenser 37 and to a switch arm of a variable inductance. A modified form of holder for the gap units is shown in Figs. 8 and 9. Longitudinal bars 65, 66 of insulating-material carry spring contact members 71 and distance-blocks 81 respectively. The spring members are contrally pivoted at 69 to brackets 67 and comprise two parallel arms 71, 72 connected by cross-pieces 73. The arm 71 has a stop 74 at its rear end and a stop 76 and lip 75 at its front end. When it is desired to remove a gap unit 31, the lip 75 is raised and the rear stop 74 pushes the unit forwards. At the same time, the arm 71 makes contact with a projection 78 on the bracket 67 corresponding to the adjacent unit, so that the circuit is maintained.