Patent GB-643868-A (GB)
Title: Typewriting machine
IPC: B41J25/18
Filed: 1947-07-08
Abstract: 643,868. Typewriters. UNDERWOOD CORPORATION. July 8, 1947, No. 18064. Convention date, Dec. 30, 1942. [Class 100 (iv)] A typewriting machine of the kind having a carriage member movable to effect tabulating runs upon a frame member, has a tabulating mechanism comprising column defining stop means on one of the members, a projectable tabulator stop on the other member, actuating means which constantly urge projection of a projectable tabulator stop from retracted position but which is normallv blocked against projection by a device responsive to an operable tabulator element, e.g. a key and also responsive to tabulation termination engagement of the stops to effect the restoration of a projected tabulator stop. As shown, a series of column defining stops 27 at letter-space intervals are mounted on a rack 26 on the rear of the carriage and are selectively depressed by hand or by key into a position in which they will engage one of a number of denominational tabulator stops in the form of sliding blades 30. Blades 30 are spaced at letter-space intervals by stops 39 thereon and are continuously urged upwardly towards projected position by springs 41 attached to rearward portions 40 of the blades, but are normally held retracted by a bail 42 engaging a forward projecting portion 45 of all the blades. In one form a blocking mechanism 43 must be selectively operated to allow a particular blade 30 to be raised. The bail 42 is operated each time any tabulator key 65 is depressed, by means of levers 124, 126 actuating a latch lever 55 so that a tongue 54 on a lever 53, urged on to the rear end of the lever 55, may now pass between the lever 55 and a resiliently pivoted secondary dog 155 thereon. Movement of the lever 53 through a shaft 52 and linkage 51, 50 permits the bail 42 to be raised by a spring 56. An extension 127 of the bail 42 and a connection link 128, simultaneously releases a dog 18 of a carriage escapement wheel 20 to permit free carriage movement up to the next tabulation stop. The mechanism 43 controlling the release of a particular blade 30 comprises four slides 61, 62, 63, 64, Fig. 8, overlying rearward extensions 40 of the blades 30 and each having a set of differently disposed notches whereby upon operation of the slides singly or in combination the notches are aligned in various ways to permit only the desired individual blade to rise. The slides 61-62 are operated against the tension of springs 72 by four bell cranks 105 actuated by Bowden cables 101-104 from a tabulator key mechanism comprising four plates 81-84 moved slidingly forward, singly or in combination according to the disposition of notches 100, by the arms 77 of the tabulator keys 65. The plates are moved to different extents due to their differing disposition from the pivotal shaft 75 but by arrangement of the four cranks 105, each of differing lengths, equal slide motions are transmitted to the slides 61-64. The plates 81-84 have a front cut-out portion 86 the end walls of which have notches and projections 88 into which a pair of levers 85, Fig. 1, pivoted at 91 on to a mounting shelf are arranged to interconnect in end-on-end relation. The arrangement is such that a parallel forward movement is imparted to the plates 81-84 irrespective of which tabulating key is depressed. When a stop 27 reaches a projected blade 30 it moves the blade and all baldes to the left thereof to the left in an opening 37 in the housing 36 and in so doing moves an arm 130 of a lever 131 which causes an actuator 133 to be brought into contact with a continuously driven power shaft 132 and thereby effects the retraction of the projected blade. The connection between lever 131 and the actuator comprises an arm 143, lever 144, pitman 145, bail 146 loose on shaft 52, and a lever 147, pivoted at 66 carrying a hooked member 166 which by its engagement with a lug 168 on the actuator 133 causes a pawl 134 thereon to engage the shaft 132 whereby a forward impulse is given to the actuator 133. By a lost motion connection 154 and a link 151 the lever 53 is rotated anticlockwise and by mechanism 52, 51, 50 the bail 42 retracts the blades 30. The tongued portion 54 is, by this action, restored to its original position behind the end of latch lever 55. If, however, the tabulator key is still depressed then the tongue 54 will be held behind the secondary dog 155 and will prevent repeat tabulation by holding the lever 53 against forward movement. The dog 155 extends slightly beyond the end of latch lever 55 so that when the depressed key is released its subsequent operation will enable the tongue 54 to move once more forwardly between latch lever 55 and the dog 155. The dog 155 may be omitted for certain classes of work where it is desired to skip columns. A palm-operated key 171 may be provided which actuates the latch lever 55, through a pivoted member 174 and the common tabulator lever 126. This lever has no connections with the slides 61-64 but the notches thereon are so arranged that with no movement thereof the left-most blade 30 is free to rise. The machine has marginal stops 177, 178 arranged to engage a lever 181, Fig. 11, held upwardly on its slotted connection 187 on a pin 182 by a spring 185 as described in Specification 530,359. Left-ward movement of the lever 181 at the line end by this engagement raises its horizontally extending arm 186 having a tongue piece engaging beneath the lever 147 which operates the actuator mechanism and thereby ensures that all projected blades are restored. If the carriage remains at line-end position, repeat operation of the actuator mechanism does not occur since the edge 168 on the actuator 133 returns above the hook member 148. A marginal release key (not shown) lowers the lever 181 on its slotted pivot 182, 187 below the margin stop by means of a forked arm 188 co-operating with a pin 191 on the lever. The full carriage movement is determined by a permanent stop 192 provided at the right end of the row of tabulator stops 27 and which upon engagement with a projected blade will cause the power operation of the actuator 133 to restore the blades. If a tabulating key is depressed when the line limit is reached the blades are prevented from rising by an extension of the permanent stop, the slides 61-64 being allowed to return freely to their normal position upon the release of the operated tabulator key. In a modification the slide mechanisms 43, 81 ... 86 and the connecting cables are omitted, the various blades 30 being released for spring projection by a hooked extension arm on each tabulator key 65. The latch lever 55 controlling the release of the bail 42 is actuated by a further hooked portion of the lever carrying the tabulator key.