Patent GB-628246-A (GB)
Title: Improvements in or relating to recording apparatus
IPC: G01R23/02
Filed: 1945-06-22
Abstract: 628,246. Counting-apparatus. PHILCO CORPORATION. June 22, 1945, No. 15946. Convention date, May 5, 1944. [Class 106 (i)] Apparatus for accurately recording at a given instant the total revolutions of a shaft rotating at substantial speed comprises means operated by the shaft for registering the number of revolutions of the shaft, means for retentively registering the condition of the first means at a given instant, thereby to retentively register the number of revolutions of the shaft at that instant, and means responsive to the operation of the second-mentioned means for making a record corresponding to the registered number. A shaft 24, Fig. 4, is connected to the shaft whose revolutions are to be totalized and carries five selector switches 18, 19, 20, 31, 22, Figs. 4 and 13, each of which includes ten stationary contacts numbered from " 0 " to " 9 " which co-operate with rotating arms 17 carried by sleeves on the shaft 24. The arrangement is such that the tenths, units, tens, hundreds and thousands of revolutions of the shaft 24 are counted by the selector switches 18, 19, 20, 21 and 22 respectively, a known form of " tens transfer " mechanism being provided between each selector switch. At a given instant therefore the position of the rotary arms 17 of the switches 18, 19, 20, 21 and 22 will give an indication of the total revolutions of the shaft 24. Each selector switch has connected to its ten contacts " 0 " to " 9 " a gas-filled discharge tube (e.g. a Thyratron), some of which are shown in Fig. 13, constituting a " number storage bank." A voltage source 85 supplies the potential for the Thyratrons the cathodes of which are permanently connected through an element 88 and one of the relays 89-93 to the negative side of the source 85. A starting potential for the Thyratrons is derived from the source 85 through a voltage divider comprising resistors 94 and 95 connected to the starting anode 84 of each Thyratron. When a relay 86, Fig. 13, is closed at any instant those Thyratrons whose circuit is closed by the rotary arms 17 receive a starting impulse and " light-up '' to store the " reading " of the arms 17. A disconnect switch 23, Figs. 4 and 13, mounted co-axially with the selector switches 18-22 serves to break the circuit to the switches during operation of the " tens transfer " mechanism and so eliminate any possibility of error if the relay 86 were closed at that instant. The relays 89-93 each jointly control an energizing circuit for a solenoid 104, Figs. 13 and 14, having an armature 110 connected at one end through a crank arm 111 to a rotatable shaft 112 and carrying at the other end a pawl 113 cooperating with a ratchet wheel 114. The armature 110 also carries a projecting finger 115, having an inclined cam 116 which is adapted to engage a roller 117 on an arm 103 connected through a link 102 to one of the contacts of the relay 86 when the armature is moved against a spring 118 to the left, Fig. 13. All the Thyratrons are arranged in a bank, shown generally at 119, Fig. 14, each horizontal row of squares representing the Thyratrons of each selector switch. The Thyratrons are disposed inside an enclosure 120, Fig. 15, with which there is associated a camera 121. When the relay 86 is closed and the selected tubes ionized, the solenoid 104 is energized causing the armature 110 to move to the left to rotate the shaft 112, thus rotating a shutter 127 on a shaft 129 until the window 128 is in line with a lens 122 and a film 123 on rollers 124, 125. The light rays from the selected tubes are thus permitted to impinge on the film 123 which records them as spots. As the armature 110 nears the end of its stroke to the left the cam surface 116 engages the roller 117, Fig. 13, to lift the link 102 and open the relay 86. Upon the return of the armature 110 by the spring 118 the pawl 113 turns the ratchet 114 to move the film 123 one frame. In the embodiment described the apparatus is used in a frequency meter calibration system described in Specification 628,245, [Group XXXVI].