GB409284A - Improvements in or relating to automatic switches for use in telephone or like systems - Google Patents

Abstract

409,284. Automatic exchange switches. AUTOMATIC ELECTRIC CO., Ltd., Strowger Works, Liverpool. Oct. 24, 1932, No. 29736. Convention date, Nov. 16, 1931. [Class 40 (iv).] A vertical and rotary switch is driven in both directions by a spring under control of a single escapement magnet the drive being through a pair of helical gear wheels and the wiper shaft being separately locked against vertical and rotary movement under control of a 2nd magnet. A 3rd magnet restores the wipers to normal. The wiper shaft may be swung clear to give access to the driving mechanism. Setting and restoring. The driving magnet oscillates the escapement anchor 7, Fig. 4, to allow the shaft 70 carrying a helical gear wheel 6, Fig. 3, to be driven step-by-step by the spring 25. The escapement anchor is pivoted to a shaft 20 the end of which is held in a plate 81 which can move slightly relatively to the main frame 26 against a spring 62 so as to take up the shock at each step. The wheel 6 is in mesh with a wheel 4 on the wiper shaft 1 which however is locked against rotation by a member 30 pivoted on a bracket 23 secured to the wiper shaft and which engages a notch in the wheel 4. The wiper shaft therefore moves down until the change-over magnet is operated whereupon armature 67 rocks the member 30 to permit rotation of the wiper shaft and prevent longitudinal movement by engagement of the member 30 with one of a number of grooves 18 in a fixed pillar 3. Restoration is effected by a 3rd magnet which by means of a pawl 60 drives the escapement wheel backwardly, re-winding the spring and restoring the wipers. Shaft-operated springs. When the switch goes off normal, the wheel 4 moves clear of a pivoted member 8, Fig. 1, which allows springs 44 to change-over. Springs 12 and 13 are operated on any desired levels by pivoted members carrying combs 51<1>, 52<1> which are engaged by a roller 9 carried by the bracket 23 on the wiper shaft. Rotary off-normal springs 15 are operated when a raised portion of a cam disc 21 on the wiper shaft moves clear of a pivoted member 22. Magnets. The magnet armatures are mounted as shown in Fig. 10 by means of a pin 85 passing through ears 88 on the armature and clamped by a member 87 secured by screws to the frame 54. The restoring spring 88<1> for the armature 69 of the restoring magnet is hooked on to the armature and at its other end is secured to a member 89 adjustable in a slot in the frame portion 26. General arrangement and mounting of parts. The switch framework comprises a portion 54 carrying the magnets and a portion 26 carrying the rest of the apparatus secured together by screws 65, 66. The driving shaft 70 has an adjustable end bearing 74. The shaft 1 to which the wipers are adjustably secured by clamps 41, 42 is held in place with the wheels 4, 6 in mesh by members 2, 32 which are pivoted to the pillar 3 to enable the shaft to be swung clear and are secured at their other ends to the frame 26 by screws 35, 36. Accurate meshing of the gear wheels is secured with the aid of shims between the members 2, 32 and the frame.