Patent GB-260386-A (GB)
Title: Improvements in or relating to chronographs
IPC: G04F13/02
Filed: 1925-09-08
Abstract: 260,386. Nehan, E. A., and Cussons, Ltd., G. Sept. 8, 1925. Recording particular operations.-In an apparatus for recording time intervals an electric motor is controlled by an electrically maintained tuning fork and drives a drum to feed a record-strip and means is provided for marking a scale on the edge of the strip and for disengaging the strip from the drum without arresting the movement of the motor. To lead the strip away from the drum it is passed over a roller in frictional driving engagement with the storage supply reel. As shown diagrammatically in Fig. 1, a tuning fork 20 is vibrated by an electro-magnet placed between its prongs, the energizing coil 21 of which is connected through a contact, and a variable resistance 22 and switch 23 to the poles of a battery 24. One of the prongs carries an insulated contact 27 which at each vibration bridges a pair of contacts 25, 26, to complete the circuit through the exciting coil 28 of a reaction or phonic motor. The armature of the motor is constituted by a disc 31 of insulating material with six insets 32 of soft iron and drives through a change-speed gearing 33 a drum 34. The drum 34 has a scale engraved on its circumference and bears against a felt roller 35 which itself bears against a similar roller 36 in contact with an inking wheel 37. A cylindrical platen 138 resting on the drum carries the record-strip which is led from a supply reel 40 over a guide pulley 43 around the platen and over a guide pulley 48 and a roller 46. The roller 46 is mounted on a counterbalanced lever 44 so as to make contact with and be rotated by the supply reel 40 to exert a drag on the strip. The marking member comprises a pen wheel 50 on an arm 49 supported upon a knife edge 51 and operated by an electromagnet 53. This mechanism is detachably supported by a platform 112 on a bracket 108, Fig. 6, and the platform carries an upright 114 to which is pivoted an adjustable ink trough 52 for the pen wheel. The spindle 82 of the drum 34 is journaled in brackets 91 secured to a pair of slotted side plates 89 and the stud shafts of the felt rollers 35, 36, and the platen 138 ride in the slots, the rollers being pressed into engagement with the drum 34 by means of a spring 102. The drum and rollers are reduced in diameter at the middle portion to prevent travel of the ink to the ends remote from the scale on the drum. To disengage the strip from the drum 34 the platen stub shaft 93 is supported in the forked end of a bent lever 94 pivoted to the side plate, the amount of movement being limited by a pin and slot 98, 99. The inking-wheel 37 is journaled in a bracket 103 on the ink trough 38 and the trough is fitted with a spring clip for holding it between the side plates and with a spring scraper for skimming the rim thereof. A set-screw in the bottom serves to adjust the ink level. The motor is shown in Figs. 2 and 3, and comprises a U-shaped frame 61 of soft iron with bearings 59, 60 for the spindle 58 of the armature 31 and pole-pieces 62, 63 for the exciting winding 28. The motor is started by a toothed sector 69 under the control of a spring 71 and movable between abutments 73, 74 the sector being released after it has been moved to engage the abutment 73. The sector carries an insulated contact spring 29 and a soft portion 75 of cork to prevent rebound when the contact 29 completes the circuits of the windings by engagement with the abutment 74. A change speed gearing, Fig. 4, is provided to connect the armature spindle 58 to the drum spindle 82; the spindle 58 has a pinion 76 adapted to engage any one of three wheels 77 - - 79 mounted on a setting plate 80 and co-operating with a set of wheels 84, 85, 83 respectively on the drum spindle.