Patent GB-190003541-A (GB)
Title: Improvements in or relating to Keyboards for Typewriters or Analogous Machines.
Inventor: BOULT ALFRED JULIUS
Filed: 1900-02-22
Granted: 1900-04-28
Abstract: 3541. Boult, A. J., [Kirby, E. B.]. Feb. 22. Type-writers and like machines; stereotype matrix machines.-Relates to keyboard mechanism for operating machines such as type-writers, stenographic machines, matrix-making machines, typesetting machines, calculating-machines, &c. The invention consists of improvements in the mechanism described in Specifications Nos. 1979 and 1980, A.D. 1898. The depression of any definite combination of keys causes the longitudinal movement of one or more of seven notched combination-bars F, Fig. 2, so as to bring some definite series of notches into alignment beneath one of the letter-bars G, which is immediately lowered into the recess so formed by the pressure of the spring G<1>. The three-armed lever J moving under the tension of the spring J<1> throws forward the universal bar H, and the rod h connected therewith releases the latch h<1> so as to permit the spring h<4> to withdraw the detent L from the striking-bar K by its pressure on the arm h<1>. The bar K is now free to descend under the tension of the spring I, and it abuts against a rod M<1> which has been pushed backward by the movement of the lever J, and so actuates the key-lever M of the type-writer or other machine with which the mechanism is combined. During the descent of the bar K and its supporting-frame k, the cam-bar k<3> returns the bar h<2> and latch h' to the normal position, and the cam m<2> on the descending rod M<1> forces the lever J forward so as to raise the letter-bar G from the aligned notches. A stop k<4> finally engages an arm n so as to release the pawl N from the detent-wheel O and allow the power shaft o to make a partial revolution, during which one of the wiper arms o<1> raises the frame k and bar K to the normal position. A buffer rod Y is employed as described in the above-quoted Specification, to prevent the bar K from descending with its full force unless it is engaged in actuating one of the shift-keys of the machine. The keyboard consists, as shown in plan in Fig. 1, of four banks A, B, C, D. each containing five keys a<1>, a<2>, &c., which are duplicated so that the operator's hands may be employed alternately. The A-bank is employed for capital letters, the B-bank for lower-case letters and punctuation marks, the C-bank for the same characters when followed by a space, and the D-bank for figures and less usual characters. The keys are provided with a special trigger-like action shown in Fig. 5. Beneath each key is a flanged plate R from which depends a forked stem r screwed into. a plug r<1>, which has a certain limited range of vertical movement under control of a spring r<2>. The rock-shafts S', S<2>, S<3>, &c., one of which is operated by each key, are provided with arms s terminating in bevelled heads s<1> which escape from beneath the blocks r<7> when the keys have been partly depressed, so that the key finally descends idly against the control of the spring r<2>. Fig. 3 shows one of the notched combination-bars F, which are made in trussed form and rest on struts e'. End stops e<2> limit their longitudinal movement, and springs e<3> urge them continually towards the right. Beneath each combination-bar is a pair of " ratched bars" T. one for each division of the keyboard. The ratchet-bars are moved towards the left by arms s<2> secured to the rock-shafts S<1>, S<2>, S<3>, &c., and carry the combination bars with them, but the detentpawls are released from the co-acting lugs e during the descent of the striking-bar K, so that the combination-bars immediately resume their normal position, even though the keys may be more slowly released. This is effected by the depression of a rod W, Fig. 2, terminating in a camsurface w<1> which operates a lever v, v<1> so as to draw down a frame x<7>, x<1> connected to the pawls When a letter is printed by the type-writer, the carriage-escapement is operated in the usual manner. The thumb-keys, however, of all four banks are adapted to actuate the escapement directly, and thus serve as spacing-keys. Each rock-shaft actuated by a thumb-key bears an arm s<3>, Fig. 2, linked to a bell-crank lever P so as to draw forward a rod p<4> and depress a rod operating the rocking-frame Q<1> which bears the escapement dogs q, q<1>. When a key belonging to the C-bank is depressed, the letter printed is to be followed by a space, so that twice the normal carriage-feed is necessary. This is effected in the following manner :-The keys of the C-bank do not directly actuate special rock-shafts S', S<2>, &c. in the manner of the other keys, but operate sleeves S<4>, Fig. 2, loosely mounted on the rock-shafts of the B-bank. When these sleeves are turned by the depression of the C-bank keys they carry the rock-shafts with them, and so produce the identical arrangement of the combination bars that would be produced by the depression of the corresponding B-bank key. The sleeves, however, bear arms s<7>, adapted to rock a shaft P' and draw forward a rod p<7> situated parallel with the rod p<4>. This effects the depression of a rod p<9>, and causes the withdrawal of a movable block q<8>, Figs 1 and 2, which normally limits the movement of the spring-actuated dog q<1> of the escapement-mechanism. The dog is then free to move through twice its normal range, and engages with the next tooth but one, instead of the succeeding tooth, of the escapement wheel Q when the rocking-frame Q<1> moves over, thus effecting a double feed of the carriage.