Patent GB-772422-A (GB)
Title: Improvements relating to recording mechanisms
IPC: G01D9/28
Filed: 1955-11-30
Abstract: 772,422. Recording-apparatus. FIELDEN ELECTRONICS, Ltd. Nov. 30, 1955 [April 19, 1955], No. 34255/55. Class 106 (4). A multi-record circular chart recorder comprises rotatable means for driving the chart, means for rotating the driving means at a uniform rate, a recording member successively positionable over the chart to recording positions corresponding respectively to the variables being recorded, marking means for marking the chart, means for advancing the driving means through a selected angular distance and means for periodically actuating the lastnamed means upon completion of selected series of marking operations. As shown in Fig. 1, records are made of the readings of twenty-four thermocouples, the recordings being arranged in four groups of six, spaced at 90 degrees around the chart. The six records in each group are made in turn by a different pen 46 of a turret 44, differently coloured inking pads being provided on marking turret 112, the chart is then swiftly advanced through one quarter of a revolution and six more readings plotted. Chart-driving means.-The chart 31, Fig. 15, is mounted on a shaft 26 and driven at a constant rate by a clock motor 30 through gears 68, 66, planet gears 62, 70 mounted on gear 66, and gear 74. The chart is advanced to the recording position for the next six readings by means of a reversible, stallable, segmental drive motor 32 driving gearing 98, 82 on the latter of which is mounted a plate 80 carrying a pawl 78 and an abutment plate 92 which has two radially extending surfaces 94, 96 engageable with opposite sides of a fixed stop 90 to limit rotation of the gear-wheel 82 to 180 degrees, the pawl 78 and a second pawl 84 carried on a support 86 engage a ratchet wheel 76 mounted on the arbor 60 carrying the sungear 58 associated with the planet gears 62, 70. As shown in Fig. 15, the assembly occupies the position at the end of a driving operation. At this point control means reverse the motor 32 to rotate the gear 82 in a clockwise direction until surface 96 of plate 92 abuts the stop 90. During this movement the ratchet 76 is prevented from rotation by the pawl 84 and the pawl 78 is moved in a clockwise direction over the periphery of the ratchet. The motor 32 is now reversed to rotate the gear 82 in a counterclockwise direction, together with the pawl plate 80 and the abutment plate 92 and the pawl 78 drives the ratchet 76 in a counterclockwise direction through 180 degrees until the surface 94 of the plate 92 once again abuts the stop 90. This half-revolution of the ratchet 76 results in a quarter revolution of the chart 31 via arbor 60, sun-gear 58, planet gears 62, 70, and gear-wheel 74. During these operations a constant time rotation is still imparted to the chart from the clock motor 30. Pen-arm assembly and pen-actuating means.- The pen-arm assembly 34 includes a lever arm 100, Fig. 8, pivotally mounted intermediate its ends on an arbor 42 and bearing at its lower end a leaf-spring 102 with a guide-element 104 having an aperture 106 to receive a penactuating shaft 108. Adjacent its upper end the pen-actuating shaft 108 is journalled in a bearing block 124 by means of a self-aligning bearing 126, the bearing block 124 being adjustably secured in a yoke 122 pivotally mounted on the end of a reciprocable shaft 48. To the upper end of the shaft 108 is secured a ratchet wheel 136, Fig. 10, engageable with a pair of spring-loaded pawls 138, 140 pivoted on the lever arm 100. On reciprocation of the rod 48 the shaft 108 and the ratchet 136 are moved away from the chart 31 causing the pawl 138 to impart a first increment of angular movement to the shaft. On return movement of the rod 48 the shaft 108 moves towards the chart and pawl 140 produces a second increment of angular movement. The resulting rotation of the shaft 108 moves one of the pens 46 on the turret 44 out of, and another pen 46, into registry with the chart 31. The rotation of the shaft also rotates, through gears 118 the rotation of the inking turret 112 to move one of the inking pads 114 into engagement with one of the pens 46. The shaft 108 is accurately located in each position by means of the twopoint engagement of an indexing plate 144 borne on the shaft with an anvil 146 secured to the end of the lever 100. The printing operation occurs on further retraction of the shaft 48 to pivot the arm 108 about the indexing plate 144 against the action of the leaf-spring 102. The shaft 48 is reciprocated by the constant speed control motor 52, Fig. 4, which drives through gearing 170, 168 a pinion 166 bearing a swash plate 164 whose opposite sides abut rollers 162 mounted in a cross-head 160 secured to the end of the shaft 48. The penarm assembly 34 is angularly positioned in a plane parallel to the chart 31 in accordance with which of the six readings in a group are being recorded and with the value of that reading by a pen-arm actuator which rotates through appropriate gearing the arbor 42 to which is secured a torque-transmitting clamp 148, Figs. 8 and 10, having an upwardlyextending arm 150 in which is threaded an adjusting screw 152 engaging a lug 154 projecting from the lever arm 100, a spring 156 acting between the arm 150 and a second lug 158 formed on the lever arm 100 biasing the screw 152 into engagement with the lug 154. Control arrangements.-The constant speed control motor 52, Fig. 4, drives through gearing 170, 168, 166, 186, 184 and 182, the shaft 180 of a bank selector switch 54, through further gearing 192, 190 the shaft 188 of a second bank selector switch 56 and through gearing 170, 168, 166, 178, 176 a bank selector actuating cam 172. The instruments whose readings are to be recorded, e.g. thermocouples 1-24 are connected as. shown in Fig. 17, with odd numbers on bank 54 and even numbers on bank 56 and the control motor 52 drives the selector arms 198, 214 and the cam 172 operating the switch 206 to switch the twenty-four instruments sequentially to the input of the penarm actuator. The constant speed motor 52 also drives, via shaft 188 a cam 194, Fig. 14, engaging a follower 224 movable with a switcharm 226 reversing the segmental drive motor 32.