Patent GB-190718919-A (GB)
Title: Improvements in Typewriting Machines.
Inventor: FELL JOHN CORRY
Filed: 1907-08-22
Granted: 1908-04-02
Abstract: 18,919. Fell, J. C., [Wyckoff, Seamans, & Benedict]. Aug. 22. Typewriters.-Line-spacing mechanism comprises a rock-shaft journaled fore-and-aft on the carriage and ratchet gearing mounted on the platenframe, the connexion being arranged to permit the platen to be shifted for change of case. A machine of the front-strike class is shown ; Fig. 1 is an end elevation of the mechanism, and Figs. 4, 9, and 12 are views of details. The carriage 7 is mounted on crossed rollers 5 on rails 4 secured to the top plate of the framework. The end plates 11 of the platen frame are connected by pivoted links 13, 14 to the carriage, and a roller 10 and a rail 8 are provided for shifting the platen. The right-hand end plate 11 receives a threaded sleeve 58 formed with a stop 60 which may engage stops 62, 63 on the carriage. The parts 58, 60 are bored to form a bearing for, the shaft 21 of the platen 22, to which is secured a line-spacing wheel 23 which is engaged by a detent roller 24 mounted on a spring 26. A rock-shaft 29 having a finger 45 is mounted in a bearing 28 on the carriage, and is tensioned by a spring 35 seated at one end in a recess 37 and at the other in a recess in a collar 41, which is secured to the shaft 29 by a stud 42. A lever 50 pivoted at 51 to the carriage is formed with a slot 47 having its walls shaped to receive a ball 46, which is apertured to receive a crank-arm 30 formed on a collar 31 secured to the shaft 29. The ball is free to slide and to turn on the arm 30. A link 53 is pivoted at 52 to the lever 50 and at 54 to a pawl 55 formed with a nose 80 and a cam part 81. The pawl is pivoted at 56 to an arm 57 journaled on a flanged collar 64 secured on the sleeve 58. The arm 57 may vibrate between a stop 83 on the plate 11 and a stop 79 on a plate 68, which may be set in different positions and serves to determine the initial position of the arm and thereby the amount of line-spacing movement. The plate 68 is mounted on the collar 64 and is provided with a pin 78 which may be seated in any of the notches 75, 76, 76 formed in a part 74 of the end-plate 11. The plate 68 is formed with an elongated bearing opening 69, and may be moved radially by a knob 73 against the tension of a spring 71 ; the plate may then be turned and the pin 78 seated in a different notch. The notches may be formed in a detachable plate which may be changed so that ratchet-wheels with different numbers of teeth may be used in connexion with the same line-spacing mechanism. In operation, the plate 68 is set in one of the notches and determines the position of the arm 57 and also the initial position of the finger 45, which on actuation turns the shaft 29 and the arm 30, thereby rocking the lever 50. A pin 84 on the pawl projects into an enlarged hole in the arm 57 so that the initial movement of the link 53 carries the nose 80 into engagement with the ratchet-wheel. The link 53 then turns the arm 58 and the ratchet-wheel until the cam part 81 of the pawl engages the detent roller 24 which together with the nose 80 is forced into firm engagement with the ratchet-wheel, whereby overthrow of the platen is prevented. The stop-pin 83 arrests the motion immediately after the cam 82 has exerted pressure on the roll 24. During the shifting movement of the platen, the ratchet-wheel and pawl move with the platen, the link 53 vibrating round the pivot 52, and the lever 50 and the rock -shaft 29 remaining relatively fixed on the carriage.