US2806925A - Wiper for stepping switch - Google Patents

Description

Sept. 17, 1957 2,806,925

D. N. M DONALD WIPER FOR STEPPING SWITCH Original Filed July 30, 1953 2 Sheets-Sheet 1 FIG. 24 66 4 a7 INVENTOR. I umwmmo Anoe rs Sept. 17, 1957 D. N. M DONALD WIPER FOR STEPPING SWITCH Original Fild July so, 1953 2 Sheets-Sheet 2 V I m :m /6.4

A TTORNEKS ou/vcmv 1v. MMDd/VALD IOA J United States Patent WIPER FOR STEPPING SWITCH Duncan N. MacDonald, Arcadia, Califi, assignor, by mesne assignments, to Consolidated Electrodynamics iglorporation, Pasadena, Calif., a corporation of Caliorma Original application July 30, 1953, Serial No. 371,372. Divided and this application October 18, 1954, Serial No. 462,697

2 Claims. (Cl. 200==166) This invention relates to improvements in wipers for stepping switches.

This application is a division of my co-pending applicatign Serial Number 371,372 which was filed on July 30, 1 53.

The parent application discloses and claims a stepping switch which comprises a supporting framework, a drive shaft journaled through a wall of the framework, a bank of contacts mounted on an outer face of the wall of the framework, wipers mounted on the outer end of the shaft and depending therefrom in engagement with the contacts, a ratchet wheel mounted adjacent the inner end of the shaft, first and second electromagnets mounted to the framework on opposite sides of the inner end portion of the shaft, first and second armatures pivotally mounted to the framework and respectively in operative association with the first and second magnets, first and second pawls pivotally mounted respectively to the first and second armatures and engageable with the ratchet wheel at respectively opposite extremities of a chord thereof, means operable to load both pawls and armatures, and means operable responsive to displacement of each armature to open the electrical circuit of the associated electromagnet.

The present invention relates to wipers which are particularly useful in stepping switches of the type disclosed in the parent application. However, the wipers may be employed in other type switches.

The wipers of the present invention are arranged to provide both flexibility and reliable support for the movable electrical contact of the wiper.

The wiper comprises an annular hub having integrally formed arms extending from opposite sides of the hub, with the outer ends of the arms being joined by an integrally formed control strip. The contact strip and the adjacent portions of the arms are slotted to provide greater flexibility. By locating the electrical contact of the wiper on a strip which is integral with and located between the support arms, reliable support is provided for the electrical contact under all operating conditions. Also, the slotted contact: strip provides independent twin electrical contacts which enhance the reliability of operation of the wiper.

The invention is explained with reference to the drawings, in which:

Fig. l is a plan view of a switch of the type disclosed in the parent application, employing the wiper elements of the present invention;

Fig. 2 is a partial front elevation of the switch of Fig. 1 showing one of the wiper elements;

Fig. 3 is a transverse section taken on the line 33 of Fig. 1;

Fig. 4 is a longitudinal section taken on the line 4-4 of Fig. 1;

Fig. 5 is an elevation view of one wiper element; and

Fig. 6 is a partial simplified circuit diagram showing one manner of utilizing the switch.

Referring to the drawing, the switch elements are supported on a framework 10 which includes a base 10A 2,806,925 Patented Sept. 17, 1957 and a front wall 10B extending perpendicularly to the base. A secondary framework 12 is supported on the wall 10B of the framework 10 and includes brackets 12A, 12B extending perpendicularly to the rear face of wall 1013. A pair of electromagnets 13, 14 are mounted respectively in the brackets 12A, 12B. An armature 15 is pivotally mounted to bracket 12A adjacent magnet 13 and an arma ture 16 is pivotally mounted to bracket 12B adjacent magnet 14.

As shown most clearly in Fig. 3, armature 16 comprises two perpendicularly disposed arms 16A, 163, the arm 16A underlying magnet 14 and being referred to as the clapper, and the arm 16B extending generally parallel to the axis of the magnet and being referred to as the driving arm. At the lower end of the arm 16B the armature includes an extension which is pivotally mounted to a support block 1d, the support or armature mounting block in turn being mounted to the bracket 1213. To provide proper lateral adjustment of the armature 16 the support block may be shimmed with respect to the bracket 12B, a single shim 19 being shown. Along the inner vertical edge of arm 16B a pair of spaced teeth 16D are formed. The function of these teeth is later explained.

A pawl 26 is pivotally mounted to the upper extremity of armature arm 16B. Pins 22, 22A are mounted to armature arm 16B above pawl 20 and extend outwardly therefrom respectively in opposite directions from both sides of the armature arm. Pin 22 carries a roller 22C held thereon by a nut 24. The pawl 20 includes a tooth 20A extending inwardly from armature 16, an upwardly extending arm 20B and a downwardly extending arm 26C, both disposed on opposite sides of the pivot point of the pawl from tooth 20A. Arm 20B of the pawl is adapted to engage against pin 22A to act' as a limit to the counter-clockwise rotation of the pawl as viewed in Fig. 3. This pin has a carnmed cylindrical surface by means of which the pawl is adjusted. Armature 15 is identical to pawl 20 and including an inwardly extending tooth 25A, an upwardly extending arm 25B, and a downwardly extending arm 25C, the two arms again being disposed on opposite sides of the pivot point of the pawl from tooth 25A. An armature pin 23 is identical to the pin assembly described in detail in relation to armature 16.

A linear U-shaped spring 26 is connected at its extremities to depending arms 20C and 25C of the respective pawls. The spring. is generally U-shaped with its base extending transversely of the rotational axis of the armatures. As previously mentioned, this spring urges the respectively engaged arms of pawls 20, 25 and also armatures 15 and i6 outwardly, i. e., away'from the center plane of the switch.

A sleeve 28 is mounted through wall 10B of the framework extending rearwardly therefrom generally parallel to the base and perpendicularly to the front wall. The sleeve has a depending flange 28A which-is anchored to the framework 10 and against rotary displacement as illustrated in Fig. 4. A tubular axle 29 is coaxially mounted within the sleeve extending outwardly from the rear end thereof. A ratchet wheel 30 is mounted on the projecting end of the axle 29. A shaft 32 is journaled through the tubular axle 29 extending outwardly from the front face of wall 10B and rearwardly of the ratchet wheel 30. Nut 33 holds the wiper assembly on an end of the shaft 32 and nut 34 binds the axle 29 to the shaft so that when thus locked they rotate in unison. However, release of the locking arrangement permits relative rotation of the shaft 32 and axle 29 for the purposes above described.

The ratchet wheel 30 is toothed around its periphery and carries a pair of rearwardly extending pins 36, 37.

A spring detent 38 is supported from the secondary framework 12 in engagement with the periphery of the ratchet wheel. The pawls 20 and 25 are in transverse alignment with the ratchet wheel so that pivotal displacement of the respective armatures responsive to energization of the respective electromagnets engages one or the other of the pawls with an aligned tooth of the wheel, displacement of the armature being such that the wheel is driven one step, i. e., through an angular rotation equal to the angle included between the center lines of adjacent teeth for each actuation of the armature. Teeth 16D on armature 16 and the corresponding teeth on armature 15 engage and lock the ratchet wheel at the extremity of armature travel to prevent overdrive of the ratchet. The detent 38 prevents counter-rotation of the ratchet wheel upon retraction of the respective driving pawls.

It is apparent from the drawing that the two armature and pawl assemblies drive the wheel in opposite directions when separately energized. V

A plurality of arcuate arranged banks of contacts 40 are mounted on the front face of framework wall 103. These contact banks are conventional and any number within the limits of the power capacity of the switch may be incorporated.

A plurality of wipers 42, equal in number to the number of contact banks, are mounted on the outboard end of shaft 32 and are insulated from each other and from the shaft by an insulating washer 43. The wipers are unique in shape and provide at the same time a maximum degree of flexibility and a maximum support at the contact tip.

One of the wipers 42 is shown in elevation in Fig. 5 and comprises an annular hub 42A from which a pair of flexible arms 42B, 42C depend supporting a contact tip 42D between the outer extremities. The arms are connected to the hub 42A at their upper extremities on the opposite side of the hub from the contact tip, and a continuous slot 42E extends along the extremity of each arm and across the contact tip. A high degree of flexibility is imparted by the slot 42B and by the connection of the arms at the upper part of hub 42A, and extra support of the contact tip is supplied by virtue of disposition thereof between the extremities of the two arms. The slotted tip additionally provides independent twin contact action.

The electrical circuit of the magnet is shown schematically in Fig. 6 and includes a number of switches actuated by the respective armatures. The circuit of Fig. 6 is described with relation to magnet 13 and armature. 15 as illustrated in Fig. 3. An input signal is connected across terminals 46, the circuit being closed by a control switch 47 externally of the stepping switch, the control switch 47 being frequently manually operated. The input signal is fed through switch 47 to a dipole switch 48 which includes a bus 48A and spring switch arms 48B, 48C, the switch normally'being closed through the arm 48B as illustrated. The arm 48B of switch 48 is connected to a second switch 50 including a bus 50A and spring switch arms 50B, 500, the connection from switch arm 48B being to the switch arm 50B of switch 50. The bus 50A of switch 50 is connected through magnet 13 to one of the input terminals.

With switch 47 closed an input signal will energize magnet 13 causing the described displacement of armature 15 whereupon the armature pin 23 releases arm C allowing it to make contact with bus 50A and immediately thereafter springing arm 5013 to break that contact. The arm 50C acts as a so-called'preliminary make-switch preventing ambiguity of armature travel. The loading spring 26 returns the armature to its retracted position and as long as the input signal remains across the terminals 46 the armature will repeat this process, stepping the ratchet wheel at each cycle until pin 37 on the ratchet wheel strikes against bus 48A of the switch 48 and displaces it from the switch arm 48B. This opens the magnet circuit and at the same time closes a circuit through switch arm 48C whereby a signal may be fed from the switch through so-called carry terminals 52 to indicate this condition. The circuit associated with the other magnet 14 is identical, as is the arrangement of the associated switches corresponding to switches 48 and 50 as described.

Rotation of the ratchet wheel responsive to actuation of the respective armatures induces like rotation of the wipers effecting a step-wise displacement of the wiper contact point along the several arcuately arranged contacts in the contact bank.

Stepping switches of this type find extensive use in many applications such as counting, data handling, and the like, such applications forming no part of the present invention. As previously mentioned, the outboard arrangement of the wiper assembly and the shaft 32 upon which the assembly is supported permits the switch to be readily converted to a stepping motor.

I claim:

1. A wiper for a stepping switch comprising a hub, a pair of arms joined to one side of the hub and extending freely therefrom in opposite directions around the major portion of the periphery of the hub, the arms being disposed substantially in the plane of the hub, the arms being joined together at the side opposite that at which they are joined to the hub, both arms being slotted longitudinally at the ends where they are joined to each other to form two coextending arm portions for a length which circumscribes a minor portion of the periphery of the hub.

2. A wiper for a stepping switch comprising an annular hub, a pair of arms joined to the hub at a common location on one side of the hub and extending freely from the hub in opposite directions around the major portion of the periphery of the hub and substantially in the plane of the hub, the arms being joined together end to end at the side opposite that at which they are joined to the hub, both arms being slotted longitudinally at the ends where they are joined to each other to form two coextending arm portions for a length which circumscribes a minor portion of the periphery of the hub, and contacts disposed on said two arm portions.

References Cited in the file of this patent UNITED STATES PATENTS

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