Page:United States patent 1108529.pdf/16

 or equivalent elements and select a particular one corresponding to the signal element by which the selector is brought into action. The feed elements of the selectors 53 and 54 are designated respectively by 55 and 56 and are here shown here as fingers having hubs formed with squared openings fitting the square guides 49 and 56 and adapted to travel therealong freely but without turning thereon. At points adjacent to the feed-screw 42 these feed elements or fingers 55 and 56 have threaded portions adapted to coact with and complementary to the screw-threads of said feed-screw. In this case each feed element has a single screw-thread adapted to engage in any groove of the feed-screw, and the two feed elements are shown coactng with, opposite sides of the feed-screw Each feed element carries the other main element of the selector, to wit, the selecting element proper, this being in the present construction a spring contact-arm secured to the feed element. These two contact-arms are designated respectively by 57 and 58 and are fastened to their respective feed elements by means of screws. Each is perforated near its upper end and is located laterally by means of a guide-pin carried by the feed clement and passing through such perforation. These guide-pins are designated 59 and 60. In order that the selectors may slide freely on their guide-rods, each feed element is preferably fastened to a relatively long sleeve, the hubs of the feed elements being extended as shown at 61 and 62 to form such sleeves. These two selectors 53 and 54 are oscillated by the squared guides 49 and 50 each time that a signal component influences the receiving instrument, and means are employed for operating said selectors reciprocally so that when one is in engagement with the feed-screw the other will always be out of engagement. These movements of the selectors are preferably controlled by an electromagnet, such as 63, which constitutes the main analytic magnet and is operated by every electrical signal element which influences the second translating mechanism. Each time that this magnet is energized and attracts its armature, which is designated by 64, it operates both of the selectors reciprocally in the manner just described, that is to say, it throws one of them into engagement with the feed-screw and the other out of engagement, the feed element 55 being engaged with the threads of the feed-screw 42 when the magnet is energized and the feed element 56 being engaged with such feed-serew when the magnet is de&euml;nergized. The armature 64 is secured in this construction to a lever being formed by two arms 66 and 67 secured to a short shaft 68 journaled at one end in the upright 44 and at the other end in a bracket 69 secured to the upright 45. The arm 67 of this lever is forked and so shaped as to form an actuator for a pair of rock-arms 70 and 71 extending from and secured to the guide-rods 49 and 50. These rock-arms constitute the means for transmitting movement to the guide-rods 49 and 50 for oscillating the selectors into and out of engagement with the feed-screw alternately. Each rock-arm also has a pin projecting laterally therefrom, these pins being shown at 72 and 73. Said pins enact with a pair of spring-arms 74 and 75 fastened to one side of the forked arm 67 of the lever 65. The ends of the forked portions of the arm 67 are so shaped as to bear on the upper and lower sides respectively of the rock-arms 70 and 71, the parts being so organized that the springs will force their respective selectors into engagement with the feed-screw, while the rigid portions of the rock-arm 67 will disengage their respective selectors at the proper times. The lever 65 is retracted in the usual manner on the de&euml;nergization of the magnet 63, a spring 76 being shown for this purpose. Accuracy of adjustment of the relative positions of the lower ends of the contact-arms 57 and 58 and the contacts over which they sweep is essential, and some provision should be made for obtaining a fine adjustment of such relative positions. This I prefer to accomplish by adjusting the sleeves 61 and 62 on the guide-rods 49 and 50, This adjustment is obtained by providing adjustable stops for determining the normal positions of the sleeves 61 and 62, that is, the positions they occupy when not in action. In this construction the hubs to which the rock-arms 70 and 71 are attached and by means of which they are keyed to the guide-rods are relatively long and are screw-threaded, these hubs being designated by 77 and 78. On these threaded portions of the hubs are mounted adjustable stop-nuts, such as 79 and 80, the inner ends of which constitute stop-walls for locating the sleeves 61 and 62 in their normal positions. By turning said stop-nuts 79 and 80 a fine adjustment of the positions of the contact ends of the arms 57 and 58 relative to the contacts over which they sweep may be effected. The direction of feed of either feed element 55 or 56 when in contact with the feed-screw 42 is from the left to the right as seen in, The return movements of these feed elements when released from the feed-screws may be effected quickly by means of springs, such us 81 and 82, each of which is secured at its opposite ends to a fixed point and to the long sleeve of its selector. The contacts with which the selecting arms 57 and 58 coact are here shown as supported by a bracket 83 fastened to the base of the analytic mechanism below the feed-screw. This bracket supports in this