Patent GB-190421116-A (GB)
Title: Mechanism for Imparting Varying Degrees of Longitudinal and Rotary Motion, applicable to a Pointer, Contact-arm or the like for use in Printing Telegraph Instruments, Automatic Telephone Switches, and for other purposes.
Inventor: HANSON ALBERT PARKER
Filed: 1904-10-01
Granted: 1906-01-01
Abstract: 21,116. Hanson, A. P. Oct. 1, A.D. 1903, [date applied for under Patents Act, A.D. 1901]. Telegraphs; telephone systems.-Relates to apparatus for imparting varying degrees of longitudinal and rotary motion to a shaft, applicable to printing telegraphs, automatic telephone switches, and other purposes. The shaft A, Fig. 6, can slide in a sleeve B, and carries an arm a, which passes through straight slots in the sleeve and engages in helical slots in a cylinder D. The sleeve B preferably carries curved metal blades, the edges of which guide the arm a and prevent it from binding in the slots. Bearings are formed in the sleeve for the cylinder D, and the sleeve is also milled flat at one end for the reception of a key B<1>, which rocks on the edge b<1>, and has at one end a pin x pressed by a spring b<2> into an aperture in the casing C, when the apparatus is at rest. Rotation of the drum D by hand or otherwise produces the desired longitudinal movement of the shaft A, but, if the key B' be rocked to the left, the sleeve B is unlocked from the case and locked with the drum, a projection y on the key engaging with one of a series of notches d<1> in the end of the drum. The moving parts then rotate together to the desired extent, the pin x bearing against the plate C. The end of a pointer A<1> can thus be brought opposite any one of a series of points, numbers, or contacts arranged on a cylindrical surface, not shown. A drum containing a spiral spring, attached at one end to the drum and at the other to the cylinder D, may be inserted in the side of the casing, tension being given to the spring by turning the drum and securing it by a set-screw. The cylinder D is pressed by the spring against a stop. In an alternative form, not shown, the sleeve B embracing the shaft A is supported, outside the drum, by two arms mounted on the axis of the drum D, and the shaft A passes through curved slots in the casing. Within the drum are a helical spring and a sliding ring having three pins projecting through helical slots in the drum, one of the pins being prolonged and fixed to the shaft A. Apparatus for imparting a step-by-step motion to the drum D electrically, as in an automatic telephone switch, is shown in Figs. 11 and 12. A lever F, pivoted at f, and normally pressed upwards against a stop by a spring, has pivoted to it two spring pawls G, h, which act on ratchet teeth D' on one end of the drum D. When an electromagnet F<1>, the armature of which is attached to the lever F, is excited, the pawl G is pressed down slightly farther than the distance between two ratchet teeth, and the pawl h glides over two teeth, so that in the double movement of the lever the wheel is revolved by two teeth. At the same time as the key B<1>, Fig. 6, is moved to the left, a sliding plate I is moved to the right by mechanism to be described later, and is retained in position against the tension of a spring i by a pawl i<1> which takes into notches in a fixed plate K. This allows a spring stop L to rest against a pin f <3> on the lever F instead of against a pin i<2> on the plate, and when the lever is next depressed, the stop slips behind the pin f <3> and limits the movements of the lever so that the wheel D' revolves by only one tooth at a time. The end of the pawl G takes into notches in the plate I, to prevent the drum from being carried forward past the pawl by its own momentum. When the shaft A has been rotated by the required distance, the plate I is moved forward another step, and a cam surface on the plate pushes to the right the pin m fixed to a lever M, and with it the pawl h, thus preventing further actuation of the drum. If the lever F be again depressed, the pawl G strikes the end of the pawl i<1>, allowing the plate I to return to its first position, and the pawl G is carried away from the wheel D'. The pawl h being held by a stop h', the wheel D' returns to the zero position, the pin x, Fig. 6, slips into the hole in the plate, and the shaft returns to its position of rest. The lever F may, if desired, be extended so as to project from the casing, in which case it may be actuated by hand. The movements of the plate I and key B' are obtained by means of an electromagnet N<1>, Fig. 12, the armature N of which carries a rigid arm n<1> and a flexible arm n. The former arm actuates a pawl o, which moves the plate I, and is attached by a pin and slot to the plate P, and pulled against stops o<3>, o<4> by a spring o<2>; the latter pushes the key B<1> away from the plate, if the pin is in the hole, and a catch slips behind the pin and prevents it from re-entering the hole, until the key is returning, when the pin lifts the catch out of the way. Fig. 15 shows the apparatus used as an automatic telephone switch, and Fig. 17 the electrical connections. The shaft A carries contact arms A' connected to the two contact pieces of an arm R, which has a flexible extension entering a slot in the plate 1. Each current sent along the line AL by the subscriber causes the excitement of the magnet F' and the protrusion of the arm A<1> by one step, on to successive rows of contacts ; a current sent along the line BL, moves the plate I and arm R one step, the latter making contact with a stud S. The arm A' is then rotated to bring it on to the desired contact. If the contact is already engaged in another part of the exchange, a current flows through a magnet U, stop S, and arms R, A' and, the armature V being raised, a stop v prevents the arm R from passing on to the through contacts S<1>. If the contact is not engaged, a second current along the line BL causes the plate I and arm R to be moved another step, so that the switch arm R makes contact with the through contacts S<1> and ringing bars TT, contact with the latter being made only while the current is actually passing along the line BL. Reference is made to Specification No. 4682, A.D. 1903.