Patent GB-854481-A (GB)
Title: Multi-position rotary electric switch
IPC: H01H21/48
Filed: 1958-09-02
Abstract: 854,481. Regulating switches. TRIGGS, W. W. (Picker X-ray Corporation Waite Manufacturing Division Inc.). Sept. 2, 1958, No. 28117/58. Class 38 (5). [Also in Group XXXV] A rotary switch comprises a pair of coaxial spaced stators each having circumferentiallyspaced contacts and an associated rotor contact arm, and driving means whereby rotation of one rotor drives the second rotor to engage a preselected contact on its stator and which also permits rotation of the first rotor independently of the second rotor to engage a preselected contact on the first stator. Three embodiments are described for voltage selection by tap-changing on a transformer, in each case one stator being associated with major voltage steps and the other with minor or unitary voltage steps (see Group XXXV). In the embodiment of Fig. 1 a U-shaped base frame 10 carries stators 11 and 12 on its respective arms 10a. Each stator has ten contacts and rotors 15 and 16 are carried on shafts 22 and 23 journalled in stators 11 and 12 respectively. Stops 46 and 47 prevent continuous rotation of the rotors 15 and 16. A hollow axle member 21 is rotatably supported between shafts 22 and 23 and carries a gear 25 meshing with a gear 27 on a spindle 28 controlled by knob 29. Gear 25 carries a pin 26 travelling in the same path as a pin 20 carried by an arm 19 mounted on spindle 22 so that rotation of gear 25 can move rotor 15. The rotor 16 is drivable via a bracket member 33 which carries two pawls 35 and 36 (see also Fig. 5), engaging a ratchet wheel 32 secured to axle 21. A bolt 40 extending from a bracket 41 fixed to the base 10 is so positioned as to lift pawl 35 or pawl 36 away from the ratchet wheel 32 when pin 26 engages pin 20-according to the direction of rotation of axle 21. This is arranged to occur when rotor 16 is on the last or first contact respectively, and disconnects the drive between axle 21 and rotor 16, since the pawl not lifted off rides freely over the ratchet teeth. Thus rotation of knob 29 first moves rotor 16 to the limit if its travel and then pin 26 engages pin 20 to move rotor 15 to its selected major voltage contact whereafter reverse rotation of knob 29 leaves rotor 15 stationary and reengages pawl 35 (or 36) to drive rotor 16 back to a selected minor voltage. Stators 11 and 12 contain internal location plates corrugated in alignment with the fixed contacts and each shaft 22 and 23 carries an arm which springs from groove to groove (Fig. 4, not shown). These location plates, with the conductive shafts 22 and 23, serve as connections to the rotors 15 and 16. In the embodiment of Fig. 9 a knob 80 drives minor rotor 70 directly and is coupled to major rotor 69 by arms 77, 78, the rubbercovered ends 77a, 78a of which can engage corresponding ends 75a, 76a of arms 75 and 76 on the shaft of rotor 69. Thus knob 80 has 180 degrees rotation free from driving rotor 69. Minor stator 61 has ten contacts as in the previous embodiment connected to unitary voltage steps, but major stator 60 has only six contacts extending over 180 degrees and these are connected to voltage steps of four units each. Thus knob 80 can freely select 0 to 4 units but further rotation steps rotor 69 to its 4-unit contact when reverse rotation of knob 80 can freely select 1 to 5 units. A further step of rotor 69 selects 8 units and reverse rotation then covers 2 to 6 units on rotor 70. Thus any desired voltage can be built up as in the previous embodiment. Location plates 73, 74 and springy arms 71, 72 are provided inside stators 69, 61 respectively. The major stator 90 and drive arrangement in the embodiment of Fig. 14 is similar to that of Fig. 9, but the minor stator 91 has only five contacts and is itself journalled in an annular housing 99, being located by spring-loaded balls 103 which engage axial grooves 102 aligned with the stator contacts. Thus 0 to 4 units of voltage may be selected on stator 91 but further rotation of knob 103 moves rotor 108 on to the next major step on stator 90 and by virtue of rotor 109 engaging lug 95 turns the whole stator 91 one step in its housing 99. Reverse movement of knob 103 can then again freely select 0 to 4 units on stator 91 (without moving major rotor 108). Thus the contacts on major stator 90 may be connected to voltage steps of 5 volts each. When reducing the selected voltage a lug 96 enables rotor 109 to step stator 91 back in its housing 99 as required.