381,733. Typewriters. TRACHTENBERG, J., 79, Wilmersdorfer Strasse, Charlottenburg, Berlin. Oct. 27, 1931, No. 29719. [Class 100 (iv).] Type-wheel machines coupling machines for simultaneous operation; hammer-impression arrangements.-A number of machines, each comprising a type-wheel and a paper-carriage, are simultaneously controlled by a single keyboard, a contact-arm running in synchronism with the type-wheels cooperating with key-controlled contacts to close the circuits of electromagnetic means on each machine for effecting impression from the type corresponding to the selected key. The machine shown in Figs. 1 and 4 comprises a continuously rotating type-wheel 24 arranged over a bed 2 supporting an impressionhammer 68, and a papercarriage 3 which is associated with the spacing, indicating, and ink-ribbon mechanisms described below. A single keyboard 91 controls a number of identical machines having the type-wheels mounted on a common shaft 128. A contact-box 76, Figs. 9 and 15, associated with the keyboard, comprises a shaft 74 running in synchronism with the shaft 128 and provided with a contact-arm 73 which is in circuit with the operating- magnets 70 of the impression-hammers and carries contacts. 86 arranged in staggered circular rows. The contacts 86 co-operate one at a time with contacts 88 carried by bellcranks 82 provided with armatures 87 for magnets 136 which are in circuit with contacts 90 in the keyboard. The contacts 90 are arranged in conical cavities and are adapted to be closed by either of a pair of contact-pins 106, 107 which are manipulated by the operator. When one of the contacts 90 is closed, the associated magnet 136 attracts its armature, and the contact 88 thereon is raised into the path of one of the contacts 86. When the selected type on the series of typewheels is at the printing point, the magnets 70 are energized, and the hammers 68 are raised to effect impression of the selected type. The contacts 86 have bevels for returning the bell-cranks 82, and over-centre springs 84 are provided for holding the bell-cranks in either normal or displaced position. The keyboard, contact-box, and one of the machines, or the keyboard only may be placed in the operator's room. Each machine may be provided with an eraser which is operated under control of the keyboard. Letter-spacing mechanism.-The carriage 3, Figs. 1 and 4, is connected to a spring drum and engages a pinion 16 on a shaft 13 carrying an escapement wheel 11 which co-operates with a rocking anchor 22. An anchor-operating magnet 25 is in circuit with the hammeroperating magnets 70, the anchor being rocked to effect letter-spacing at each operation of the hammer. The keyboard 91, Fig. 15, includes contacts 112 for closing the circuit of the magnets to effect word-spacing, impression being prevented by a blank in the type-wheels 24. Word-spacing may be effected also by means of a contact 115 which closes the circuit of the magnets 25 only. Back-spacing mechanism.-The keyboard 91, Fig. 15, includes a contact 113 for closing the circuit of a magnet 29 having an armature 28, Fig. 4, connected to a back-spacing pawl 27 which co-operates with a ratchet-wheel 12 on the shaft 13. The pawl is normally disengaged from the ratchet-wheel, and a ratchet-coupling 18 is provided for preventing movement of the escapement wheel 11 during back-spacing. Carriage-returning mechanism.-The carriage 3, Fig. 1, is provided with a core 9 which is drawn into a carriage-returning solenoid 10 when the latter is energized by closing a contact 119, Fig. 15, in the keyboard 91. Line-spacing mechanism ; web-feeding arrangements.-A web 46, Figs. 1 and 4, passes through pairs 49, 50 of feed-rollers on the carriage 3, and is led from a delivery roller 47 to a winding- roller 48 mounted on the bed 2, bights 67 permitting movement of the carriage. The top feed-rollers are geared together by means of a shaft 60 and are provided with ratchet-wheel 55 for co-operating with normally disengaged pawls 52 which are connected to the armatures 56 of magnets 57 arranged in circuit with contacts 120, 121, Fig. 15, in the keyboard. When the contact 120 or 121 is closed, the feed-rollers 49 or 50 are operated, and the web is line-spaced forwards or backwards respectively. The shaft 60 is connected by gears and a flexible shaft 63 to a shaft 65 which is geared to the delivery and winding rollers. The delivery and winding rollers are detachably mounted at each end on bearings consisting of pins 129 carrying spring-urged discs 130 having projections 132 for engaging recesses in the rollers. Carriage scales and indicators.-The position of the paper-carriage 3, Fig. 4, and the number of line-spaces imparted to the web 46 are indicated by pointers travelling over scales 94, 93, Fig. 15, respectively on the keyboard. The carriage-pointer is traversed under the control of an escapement which is operated by a magnet 117 in circuit with the magnet 25. The carriage-pointer is returned by a solenoid 99 in circuit with the solenoid 10. The linespacing pointer is traversed by means of ratchet mechanism operated by a magnet 139 in circuit with the magnets 57. The linespacing pointer is returned manually or by means of a solenoid. Ink-ribbon mechanism.-A length of tricolour ribbon 37, Fig. 4, arranged across the web 46 is secured to a frame 35 which is mounted in guides 38 on the carriage 3 and is shifted for colour-change by means of a lever 40 having an armature 42 arranged between magnets 44, 45. Normally the lever is held in mid-position by springs 43, and the middle stripe of the ribbon is effective. By means of contacts 124, 125, Fig. 15, in the keyboard, the circuit of either of the magnets can be closed to shift the ribbon to one side or the other and thereby effect change of colour. A ribbon wound on spools may replace the above-described arrangement.