Patent GB-163852-A (GB)
Title: Improvements in letter spacing and back spacing mechanism for typewriting machines
IPC: B41J19/18
Filed: 1920-03-17
Abstract: 163,852. James, R. W., (Remington Typewriter Co.). March 17, 1920. Letter-spacing mechanism.-The dog-rocker is mounted on a detachable bracket carrying a second detachable bracket in which is mounted the escapement-wheel shaft, the arrangement enabling the shaft and rocker to be inserted or removed either separately or as one unit; the shaft and rocker may be arranged above and below the top plate of the machine respectively; further, to permit adjustment, the shaft and the rocker may be detachably mounted in the brackets. As shown, the rocker is mounted in a bracket 39, secured by screws 41 to the top plate 3, and the escapementwheel shaft 57 is mounted in a bracket 40, which is secured by screws 54, 54a to the bracket 39 and projects through a hole 3a in the top plate. The rocker is trunnioned on a screw 44, Fig. 1, and a pin 47, which is secured by a stud 49 and can be withdrawn to permit detachment of the rocker. The rocker may, as described in Specification 162,488 be actuated by a link having a fork engaging a pin on adjustable arm on the rocker. The shaft 57 is formed with reduced ends 56, 61, Fig. 7, mounted in a bearing 55 in the bracket 40, and a sleeve 59 secured by a split boss 58 on the bracket. The boss is formed with a rigid and a yielding arm connected by a tightening-screw 60. The rigid arm is not moved by the screw, and thus prevents the sleeve from being moved out of centre. On loosening the screw, the sleeve can be withdrawn to permit detachment of the shaft. Longitudinal play of the shaft is prevented by the engagement of the end shoulders with the bearing 55 and sleeve 59. The escapement-wheel 68 is secured by screws 71, Fig. 7, to a shouldered disc 70 which is secured to the shaft by screws 72 engaging flats 73. The shaft carries a loose sleeve 62 formed integrally with a feed-pinion 6, and a ratchet-wheel 63 co-operating with a coupling- pawl 78 on the disc 70. The ratchet-wheel may be formed with external teeth 76 for engaging a back-spacing pawl 85, described below, the teeth being formed by making cuts through the rim 63<a> of the wheel; the bases of the teeth form internal shoulders 77 or teeth for engaging the coupling- pawl. This method of forming the teeth permits the formation by the same series of operations of registering external and internal teeth. The coupling-pawl is pivoted on a pin 79 and is formed with a nose 84, Fig. 1, for engaging the teeth 77, engagement being maintained by a spring 82 which can rock slightly on a pin 83 and abuts on the top of an enlarged opening 80 in the pawl. The sleeve 62 bears on the shaft 57 only at the ends and is formed with an oil hole 66. Longitudinal play of the sleeve is prevented by a flange 69<b> on the disc. Specifications 105,865 and 111,461 are referred to. Back-spacing mechanism. - Back-spacing devices may be included in the above-described unitary arrangement of escapement-wheel shaft and dog-rocker; the devices may be mounted on the bracket 40, and are preferably, as shown, mounted on a bracket 90, Figs. 1 and 3, which is detachably secured by screws 91 to the bracket 40, thus enabling the bracket 90 to be removed or inserted separately or together with the bracket 40 or together with both brackets 39, 40. The backspacing devices shown consist of a pawl arm 85 which passes underneath the escapement-wheel shaft 57 and is pivoted at 86 to a lever 87, pivoted at 88 to an arm 89 of the bracket 90. The pawl arm is formed with a nose 92 for engaging the teeth 76 of the wheel 63. A spring 93 normally holds a padded lug 96, Fig. 1, on the lever 87 in contact with an adjustable stop secured to the side of the lever. The pawl arm is pivoted at 101 to a link 36 connected to an arm 32 on a rockshaft 24 which is mounted in lugs 25 depending from the top plate 3, and is provided at one end with an adjustable arm 21 connected by a link 18 to the lever 7 of the back-spacing key 10. On depressing the key, the pawl is raised to cause the nose to engage the teeth 76, and at the end of the movement the nose is locked in engagement with the wheel by the engagement of a pin 102 on the link with the edge of the pawl arm. The rockshaft 24 and the key lever 7 are provided with returning-springs 28, 9 respectively. For detachably connecting the link 36 to the arm 32, the link is formed with an eye which engages the reduced end 35, Fig. 1, of a collar 33 on the arm, and is retained by the head 37 of the screw. The connection is rendered accessible by being arranged below the bracket 39. The usual spring-urged hook 105 for holding down the feed-rack 5 is normally held in the released position by means of a pin 103 on the pawl arm engaging a lug 104 on the hook. When the pawl arm is raised, the pin 103 releases the lug and permits the hook to swing over the feed-rack. Keys.-The stroke of the back-spacing key 10 is limited by an adjustable stop-screw 12, Fig. 3, and a pad 15 which engage lugs 11, 14 on the key lever 7 respectively. The stop-screw passes through a tapped hole in a support 13 and is secured by a nut 12<a>. A reinforcing-plate 13<a>, tapped to receive the screw, may be welded to the plate. To permit close spacing of a set of stop-screws for the spacekey, shift-key, &c., the nuts may be arranged alternately above and below the supports. The comb teeth 16<a> for guiding the back-spacer keylever 7 are strengthened by being united at the bottom 16<b>.