Page:United States patent 1108529.pdf/20

 cated in a code character received by the instrument said magnet 164 will be energized, by means which will be hereinafter described, to oscillate the shifting-lever 155 in the opposite direction to that in which it is oscillated by the dash magnet 162, thereby shifting the drum 143 and all of its character-selecting components back one step. In these shift movements of the drum 143 to the shiftable pins 141 and 142 controlling the long dashes representing the “L” and “O” in the Morse code maintain their relative positions to the drum and the other pins and oscillate about their points of connection with the angle-levers 146 and 147, as will be clear by referring to. Movement of the drum 143 in a rotary direction about the axis of the shaft 92 is prevented in this construction by a pin 165 carried by a post 166 rising from the base 113 and by a forked member 167 secured to said drum and embracing the pin 165, this pin being long enough to permit the drum to assume any of its three positions lengthwise of the shaft 92. The two shift positions of the lever 155 may be accurately determined by means of adjusting-screws, such as 168 and 169. This lever in its normal position is clear of said adjusting-screws and of the poles of the two magnets 162 and 164, as will be seen by referring to, and in this case is held in said normal position by means of a spring 170 connecting a pair of short levers, the free ends of which are in engagement with a depending arm 171 secured to the free end of the lever 155. The two short levers connected by the spring 170 are designated 172 and 173 and are pivoted on a plate 174 secured to the upper end of a pair of posts 175 rising from the base 113. The normal positions of these two levers 172 and 178 are indicated in, they being at such time in contact with stops, such as the pins 176 and 177 fastened to the plate 174. The spring 170 is of sufficient strength to hold all three of the levers 155, 172 and 173 in their normal positions and return them thereto when not operated on by other elements. The arm 171 depending from the free end of the lever 155 carries at its lower end a pair of by-pass pawls 178 and 179 (see particularly ) these pawls being pivoted in this case on a plate 180 constituting an extension of the arm 171. A spring 181 serves to force the upper ends of these pawls normally outward beneath the under sides of a pair of levers 182 and 183 (see Figs. and ). Whenever the dash magnet 162 is operated the arm 171 is forced to the right in and the pawl 179 moves away from its lever 183 at such time and the end of the lever 183 is depressed. When the arm 171 is moved to the left in said figure, on the operation of the space magnet 164, the pawl 178 moves away from its lever 182 and said lever is depressed in the same manner as the lever 183. The two levers 182 and 183 are in this construction carried by an insulating block 184 secured to the base 113, and serving normally to 70 close respectively a pair of circuits through two different pairs of contacts also secured to said insulating block and all insulated from one another. The levers 182 and 183 are insulated at the points where they engage the lower contacts and their respective sets (see ). The contacts of these sets are designated respectively 185, 186, 187 and 188. The principal object of these contacts is normally to close circuits controlling the action of the magnets 162 and 164. They also serve, by their resiliency, to depress the respective levers 182 and 183 when released by the corresponding pawls 178 and 179.

There are no code characters in the Morse code in which a dash occurs after an extra space, and similarly there are no code characters in said code in which an extra space occurs after a dash. Because of this I provide means for preventing the energization of the dash magnet 162 in any code character after the spacing magnet 164 has been operated and for preventing the energization of the spacing magnet 164 in a code character after the dash magnet 162 has operated in the same character. I accomplish this result by depressing the lever 183 in the manner just described whenever the dash magnet 162 is operated, the pawl 19 releasing said lever at such time, thus breaking 100 the circuit of the contacts 187 and 188 and preventing the energization of the spacing magnet 164 which such contacts control. When the spacing magnet 164 is operated the lever 182 is depressed, as before stated, the pawl 178 moving inward and releasing said lever at such time, thus breaking the circuit to the contacts 185 and 186 and preventing the energization of the dash magnet 162, which such contacts control. The levers 182 and 183 thus operate reciprocally for each series of signals representing a code character, the organization of the mechanical parts and the connections of the circuits being such as to prevent, the release of both levers during the reception of the signals of a single code character, that circuit which is first closed through the contacts 185, 183, or 187 and 188 serving to prevent the closure of a circuit through the other two contacts. In this construction said levers 182 and 183 are depressed by the contacts 186 and 188 respectively, which are shown (see ) as spring arms. The other movement of the levers 182 and 183, to wit, the elevation thereof, is effected in any suitable manner after a series of signals representing a code character has been received, they being restored to their normal positions in which they close the contacts 185,