US2438970A - Preset switch - Google Patents

Description

April 6, 1948. M. L. GLOGAU PHESET SWITCH Filed April s, 1944 4 Sheets-Sheet l R v O INVENToR. #www Z. zama BY .f

,@WJ M PI' 6, 1948. M. L. GLOGAU PRESET SWITCH Filed April 3, 1944 4 Sheets-Sheet 2 INVENTOA #Z4/mem 620640 l BY @and Q. 5574 mmm/5y.

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maud Apr. s, 194s UNITED STATES PATENT OFFICE PRESE! SWITCH Manfred L. Glenn. Shorewood, Wis.. udxnor to Allen-Bradley Company, Milwaukee, Wis., a corporation of Wisconsin Application April 3, 1944, Serial No. 529,356

7 Claims. ((1200-45) This invention relates to electrical switches for selective establishment of a plurality of alternative circuit connections and resides in a novel combination of circuit elements including a magnetic contacter switch and circuit selective elements, and also in a novel arrangement of electrical and mechanical elements by which alternative circuit selection may be established prior to admission of load current, and terminated subsequent to discontinuance of load current whereby power oi moderate magnitude may be alternately controlled by a standard magnetic contactor oi appropriate size for the power to be controlled'and a simple and compact switching device of very'small dimensions.

Heretofore where electrical power of moderate magnitude has been switched to admit or discontinue the same in a plurality of alternative circuits, as for the reversal or speed control of motors such as are employed for the actuation of machine tools, hoists and the like, it has been the common rule to provide selectively engageable contacts which in and of themselves act to admit and interrupt the load current. In so doing each pair ci. selective contacts or commutating members must be oi suiiicient size to withstand the arcing attendant upon interruption of the load current. For example if simple reversing of a motor is to be accomplished, either a commutating drum capable oi withstanding the load current, or a pair of mechanically interlocked magnetic contactcrs both of suiilcient size for the purpose must be employed. Where space is limited the cumbersome commutating drum often cannot be used, and if the pair of mechanically interlocked magnetic contactors are employed the expense of duplication of switching facilities half of which is idle at all times is involved. Where more than two alternative circuits must be provided for an increase in the problem in proportion to the number oi alternative circuits required is encountered.

An object of this invention is to provide a small compact and comparatively inexpensive device which when employed in conjunction with a single standard magnetic contactor switch, wili permit of the selection of a plurality of alternative circuits.

This invention is herein described by reference tothe accompanying drawings forming a Daft 2 hereof in which there is set forth by way of illustration and not of limitation two specific forms in which the apparatus ofthis invention may be embodied. In the drawings:

Fig. 1 is a side sectional view of one form of the apparatus of this invention,

Fig. 2 is a top plan view with cover removed of the apparatus of Fig. 1,

Fig. 3 is an end view in elevation of the apparatus of Fig. 1.

Fig. 4 is a sectional view in end elevation ci the apparatus of Fig. 1 viewed through the plane l--I indicated in Fig. 1, i

Fig. 5 is a sectional view in end elevation of the switch parts only of Fig. 1 viewed through the plane 5 5 indicated in Fig. l,

Fig. 6 is a sectional view in end elevation of the switch parts only of Fig. l viewed through the plane S-S indicated in Fig. 1,

Fig. 7 is a fragmentary plan view in section of the switch parts appearing in Fig. 6, viewed through the plane l-l there indicated,

Fig. 8 is a sectional view in end elevation of the switch parts only of Fig. l viewed through the plane 8 8 there indicated,

Fig. 9 is a sectional view in end elevation ci the switch parts only of Fig. i, viewed through the plane S- there indicated,

Fig. 10 is a side view in elevation and in section of a somewhat simpler form of the apparatus of this invention,

Fig. 11 is a top plan view of the apparatus of Fig. 1D shown with the cover removed, and with parts of the actuating handle and lock shown in section, l

Fig. l2 is an end view in elevation and in section of the apparatus oi Fig. l0 viewed through the plane i2-l2 there indicated,

Fig. 13 is an end View in elevation and in section of switch parts only of the apparatus of Fig. 10 viewed through the plane l-ltthere indicated,

Fig. 14 is a circuit diagram illustrating one method of connecting the apparatus of Fig. i. in circuit with a magnetic contactor, and

Fig. l5 is a circuit diagram illustrating o -e method of connecting the apparatus of Fig. 10 in circuit with a magnetic contacter.

The apparatus depicted in Figs. 1 to 9 inclusive is adapted for connection with a single and i9 by through bolts 26 and 2l.

standard magneticv contactor as diagrammatically indicated in Fig. 14, to cause reversal of a three phase induction motor. In so doing the admission and interruption of load current is accomplished entirely by the magnetic contactor, withselector contacts which accomplish the reversing function being arranged to engage and disengage only when load current is excluded by open condition in the magnetic contactor. To this end the apparatus of Figs. 1 to 9 is provided with parts to be hereinafter referred to for energizing the magnetic contactor and with separate parts for preselection of alternative circuits.

. Referring now particularly to Figs. 1 to 4 inclusive, the apparatus there shown is provided with a housing comprising a sheet metal base having a bottom I and upturned ends 2 and 3, and a separate complementary trough-shaped sheet metal cover 4 held in 4place by screws 5 and 6. Through a bushing 'I rigidly held in vertical end 3 by threaded engagement with nuts as shown, an axially and rotatably movable cam shaft 8 enters the housing referred to. An operating handle 9 is secured to the shaft 8 by set screw I as shown.

The inner end of shaft 8 is hexagonal in shape so as to permit a sleeve of insulating material II having a polygonal hole therein to be non-rotatably held thereon. To hold sleeve il rigidly against laxial movement with respect to shaft 8, a c washer I2 held in a groove provided therefor in shaft 8 is placed at one end, and a slipconnection plate I3, washer i4 and screw I5 is provided at the opposite end.

Surrounding shaft 8 and sleeve Il is an electrical contact mounting made up of interlocking segments of insulating material i6 and I1 clamped tightly together between endplates I8 The endplate I8 receives its support from bushing I and is held against rotation in the housing by a standoff rivet 22 as shown. Bearing support for the inner end of shaft 8 is provided by engagement of the cylindrical surface of sleeve Il with a circular opening provided therefor in endplate I9.

Shaft 8 as previously noted is mounted for and capable of axial movement and to provide for control of such movement and to cause said shaft to be self returning to a mid-rest position, a caged spring 23, is interposed between washers 2B and 25 through which shaft 8 is free to slide. Since washer 25 engages stationary bushing 'I and washer 24 engages segment I6, shaft 8 occupies a normal or rest position corresponding to the full line position of handle 9.

Shaft 8 and handle 9, however, are capable of Y being moved axially to either of the positions indicated by dash dot lines when suflicient force is applied thereto tovovercome the spring 23 which preferably is under a small initial compression.

Surrounding sleeve II and formed as a part thereof is a circumferential boss 26 the outer margin of which is arcuate in configuration as shown. Boss 26 is provided with two diametrically located gaps which are horizontally disposed when shaft Il is in mid-angular position as illustrated by full lines in Fig. 3. The character and disposition of the gaps in boss 26 are clearly shown in Fig. 6.

Embraced and securely held by socketed engagement between segments I6 and I1 are movable contact mountings 21 and 28 carrying upwardly-extending, resilient, movable contact carriers 29 and 30, bearing movable contacts 3| and 32 at their upper ends. Also held between segments I6 and I-'I are stationary contacts 33 and 34 disposed respectively to be engaged by movable contacts 3l and 32. Secured to carrier 29 is a follower point 35 adapted to be engaged by boss 26 to cause engagement of contacts 3l and 33 whenever shaft 8 is away from mid-angular position, and when in either mid or outer axial position. Secured to carrier 33 is a follower point 36 adapted to be engaged by boss 26 to cause engagement of contacts 32 and 34 whenever shaft 8 is away from mid-angular position and when in outer Iaxial position.

While shaft 8 and handle 9 are free to move axially in any selected angular position, angular movement -is subjected to limitation by reason of engagement of slip connection plate I3 with stopping means provided therefor. Plate i3 as appears clearly in Fig. 5 is of roughly semi-circular shape limited in total angular displacement by stop pins 39 and 43 and provided with a series of circumferentially spaced perforations adapted for sliding engagement with stationary stop pin 31 rigidly7 attached to endplate I9. As appears in Fig. 7 the length of the stop pin 37 is such that it precludes angular movement of shaft 8 except when in inner axial position only.

The parts thus far described constitute the parts for causing energization of the magnetic contactor and for recapitulation of the function of which this part of the apparatus is capable,

it is noted that with handle 3 in mid-angular position as illustrated in Fig. 3 it may be moved to any of the three axial positions 3, 9A or 6B illustrated in Fig. 1. In any of these no displacement -of contacts 3l and 32 occurs because of the gaps in boss 26. In either of the other two Iangular positions of handle 9 designated in Fig. 3 FOR (forward)y and REV (reverse) neither contact 3l or 32 is displaced in extreme inner axial position 9A, but in mid-axial position 9, contact 3l is displaced to engage contact 33, and in extreme outer axial position 9B, both contacts 3l and 32 are displaced to engage contacts 33 and 34 respectively. The sequence of engagement starting from mid position angularly and nor- The same sequence is followed with entirely comparable results in entering land leaving REV" from mid-angular normal axial position.

Additionally it is feasible to pass directly from step '7 of the FOR sequence to step 3 of the REV sequence and vice versa to bring about engagement of contacts 3l and 32 with their corresponding stationary contacts without returning through steps 8 and 9 and reentering the sequence through steps 1 and 2. In all other respects the sequence of steps cannot be varied because of the engagement of pin 3l with slip conraiection plate I3 and motion limiting pins 39 and Rigidly attached to the contact mounting assembly comprising segments I6 and Il, is a switch body composed of segments 4I, 42 and 43, having a polygonal shaft 44 with a cylindrical end 45 joined in a bushing 46 held in an endplate 41 by a threaded engagement with a nut 48. Shaft 44 is held against endwise displacement' by C rings received in slots in shaft 44 provided therefor, the same being disposed on opposite sides of bushing 46. Received on shaft 44 are insulating cam sleeves 48 and 50 which are spaced endwise by end collars 5| and 52. A screw 53 engaging the end of shaft 44 forces a cup washer 54 against the hub of a biiurcated arm 55 urging the same against the end collar 5 I' thus clamping the shaft- Y borne cam sleeves 49 and 50 in place.

The ends of bifurcated arm 55 terminate in parallel pins 56 and 51 rigidly united thereto which form a. slip connection with perforations provided therefor in plate I3. Arm 55 is provided with a, polygonal hole at the point of its engagement with shaft 44 and therefore must rotate therewith, and by reason of this and the engagement of pins 56 and 51 with plate i3, shaft 44 must at all times follow the angular movement of shaft 8 although it is at the same time incapable of axial movement and is independent of the axial movement of shaft 8.

A serrated indexing wheel 58 having a hexagonal hole engaging shaft 44 bears against coliar 52 and is held in place thereby. Hvotally mounted upon plate il is a detent arm 59 bearing a. detent roller til positioned to cooperatively engage the seri'ations in wheel 58 the same being urged into engagement by a spring Bl mounted as shown. Vniile the wheel 58 is shown with serrations throughout its periphery, it will be understood that but three of these come into play, the remaining ones being provided only to facilitate revision oi the structure for other function in the event that such be desirable. rllhis datent mechanism provides the necessary restraint and ieel by which the three selected angular positions can be achieved quickly and positively.

Held in place between segments 4i and 42 are movable contacts 92 and 63 and stationary contacts tti and 65 and in like manner between segments l2 and i3 are movable contacts 66 and 5l and stationary contacts 68 and t9. These segmental switch parts including contacts, thus assembled, are held together by through bolts l0 and "di, and are constructed in accordance with my Patent No. 2,319,503, issued May i8, i943, and therefore are not described in greater detail. Bolts iii and 'll respectively threadingly engage spacersleeves l2 and i3 and thus rigidly unite all of the switch contact mountings, including segments i6, il, di, 42 and 43. Plate 4l at its lower end is provided with a T slot positioned and conformed to engage the head of rivet "i4, secured to the base i whereby the entire switch assembly is rigidly fastened within the housing but is readily removable as a unit simply by removal of the outer nut engaging Ibushing Cam i9 as appears more clearly in Fig. 8 is provided with a cam point'l which comes into play to cause engagement of contacts 62 and 64 whenever e is in the FOR angular position and a cam point 16 which comes into play Whenever 9 is in the RE-V angular position. Cam 50 as appears more clearly in Fig. 9 is provided with a cam point 'i8 which comes into play to cause engagement of contacts 61 and 69 whenever handie 9 is in the FOR angular position and a cam point l'i which comes into play to cause engagement of contacts 66 and 68 whenever handle 9 is in the REV angular position.

In -Fig.. 14 is illustrated the use of the apparatus above described for controlling a reversible 3 phase induction motor 'I9 having an overload cut out switch 3D.

In this application a three wire pilot circuit is used providing for low voltage protection; also the provision that on occurrence of overload'the control lever must be manually operated before motor is energized again. Also an important feature is obtained in this illustration, namely, with motor running in the normal forward or reverse position the power may be disconnected instantly by pushing the control handle inwardly.

For this purpose a single standard magnetic contacter switch designated generally by the numeral 9|' is connected to join the line leads 8l, 82 and 83 respectively with leads 84, 85 and 86. Switch SI is provided with bridging contacts 81, 88 and 89 proportioned to interrupt load current without damage. Lead 86 is joined to contact 62 and by bridging conductor 92 to contact 63, lead 84 is joined with contact 66 and by bridging conductoi- 93 with contact 61. Lead 85 is joined permanently with one of the terminals of motor E9. Another terminal oi motor i9 is joined by the lead 94 and bridging conductor 95 with contacts S4 and 68. The remaining terminal oi motor i9 is joined by lead 96 and bridging conductor 9i with contacts 68 and 65, to complete the load carrying circuit elements.

In the control circuits line lead 8i is arranged for .permanent connection with contact 34 by means oi lead 98, while Contact 33 is joinedior access to lead 8i through lead 99 and magnetically controlled auxiliary contact E00. Movable contacts 3i and 32 are joined by a. bridging conductor i0! and connected through lead |02, overload switch i3d, and lead ID3 with one end of magnet coil 9B the opposite end of which connects through lead 04 to line lead 82.

it will be observed by reference to the foregoing sequence table, that immediately on at tainment of step 3 FOR, contacts 62 and S4 engage and also contacts 61 and 69, but no load current passes becafuse contactor switch 9i is still open. This condition still prevails in step i FOR since engagement of 3I and 33 occurs with i still open. However upon attainment oi step 5, v32 and 34 engage supplying control current from lead 93 to M12, 80, and l3 to the magnet coil 90. Thereupon the switch 9i closes which includes the closure of lllfl.

The operator may now release the handle 9 and it will move of its own accord to and be mechanically self-retaining in step 6 and the circuit will be electrically self-retaining also so that motor i9 will conti-nue to run in the iorward 'direction until an overload causes 86 to open or until the operator presses handle 9 to `move to step 7. Since step 5 cannot be achieved `without rst passing through step 3 and since step 8 cannot be achieved without rst passing through step 7, contacts 62 to 69 inclusive can never be called upon to either make or break a load; circuit. This is equally true in the REV" sequence and also in the short cut between FOR and REV.

The presetting oi the selector contacts and the control of admission of load current by the magnetic contactor switch makes feasible the use of selector contacts of very much lighter and simpler character permitting the assembly of Figs. 1 and 2 to be constructed in extremely compact :form considering the magnitude of load current passing therethrough.

The apparatus of this invention may be conateatro structed in somewhat simpler form based upon the two wire system of control as appears in Figs. 10 to 13 and 15. In this case a similar housing made up of a base with upstanding ends |00 and |00 and a cover not shown is provided. ,An axially shiftable rotatahle shaft |01 enters the housing through a bushing |00 locked in place in end |00 by nuts as shown. Shaft |0i carries adjacent to the locked. in place C washer |01, and rigidly associated therewith an index ing wheel |00 which cooperatively engages a grooved detent roller ||0 mounted Vto slide axially on horizontal pin i carried upon pivoted detent arm H0. A spring urges arm iid, pin and roller ||0 into engagement with wheel |05 at all times.

Inwardly adjacent to the wheel |00 and rigidly secured to shaft |01 is a cam sleeve M0 of insulating material having a boss `iiii arcuately formed on its outwardly facing side. The boss H0 has a peripheral gap it as appears more clearly in Fig. 13. Boss H0 is disposed in a cell formed between insulating contact supporting segments ||1 and M0 in position to engage the follower point ||9 of e. movable contact carrier |00 mounted therein. Carrier |00 is provided with a movable contact disposed at its upper end in position to engage a stationary contact |2|. The parts thus far described are those whose function it is to control the energization of a magnetic contacter load switch.

Beyond the sleeve idd are two cam sleeves |20 and |20 disposed respectively in cells formed between insulating contact mounting segments H0 and |89, and |00 and |20. Sleeve |22 is provided with cam points |20 only one of which is shown, and sleeve |23 with cam points |26 only one of which is shown. The points |25 and |20 are disposed similarly to cam points 15, 10, 11, and 10, and are adapted to actuate contact pairs |21|28, IZB-|30, itl-|32, and i3d-|34 in an entirely similar fashion.

A cylindrical spacer sleeve |35 at the end of shaft |01 passes through a circular end plate |36 which serves as a journal in which the same may freely move both axially and angularly. End plate |36 in conjunction with end plate |31 and through bolts and |39 serve to bind the contact supporting segment assembly into a unitary whole.

Secured to the inner end of shaft |01 to turn and move axially therewith is a rotation-stop finger |40, carrying a. short pin |4| which is dis-A posed parallel with shaft |01. Pin |4| is adapted to selectively engage three perforations |42 formed in end plate |36 and when in engagement with any one of them to prevent the turning of shaft |01 but at the same time to permit free axial movement thereof.

Beyond the end of shaft |01 and held in place by spacer sleeves |43 and screws |44 is a spring seat |45, which serves as a means for retaining a spring |46 which bears upon the end of shaft |01 and constantly urges the same to its outerA axial position determined by engagement of C washer |41 with the inner end of bushing |08.

A C washer |90 is provided on shaft |01 to limit inward motion of shaft.

By reason of the construction above described shaft |01 and associated parts can occupy two axial positions, i. e. an inner and an outer position and can occupy three angular positions, i. e. a mid-position, FOR position and a REV position. Further it will be apparent that angular movement can only take place while shaft |01 is occupied in its inner anni position. Motion sequences mechanically imposed are therefore subject to the limitation that angular change in outer position can only taire place with an in= tervening axial inward position.

This sequence tation is availed of hy so positioning follower point |0 with respect to boss H5 that contacts |20 and |2| are brought into engagement whenever shaft |017 is in its outward axial position except when gap ||0 is in registry with follower point M0, which latter occurs only when shaft |01 is in its mid angular position. Furthermore cam points |05 and |20 are o s cient axial extent so as to perfo their ctlon of causing engagement of the contacts cor==I responding thereto when shaft |00` is in either its inner or outer position.

Starting therefore with shaft |00 in its misil angular and outer axial position, the following functions are available:

Knob |00 is non-rotatable in the position assumed at the start and it must iirst be forced inwardly to permit it to he turned. if er. r .1.; ed to the right to the inward EUR position contacts |00- 130 and iii-|20 are engaged. Ei shaft |01! is then permitted to return to its outer axial posi tion without rotation contacts |20-|2| will hecome engaged in addition to those already named. Further movement from the latter position can only be achieved by again forcing hnoo |00 and shaft |01 inwardly and when this is done contacts |20-|2| separate. Following this knob |630 can be turned either to mid position and released to disengage all contacts or to REV angular position to engage contacts 50i-|02 and |20- |00 whereupon contacts |20- |2| may he reengaged by allowing axial return of shaft |00 to its outer axial position. Of course the sequence outlined. may be reversed if desired, that is to say, REV positions may be entered instead of FO "t positions and outer mid position can be reached from either without passing through the other.

Set forth in Fig. 15 is a circuit adapted to utilize the properties of the apparatus of Figs. 10 to 13. There is here shown a three phase induction motor |50 with its three terminals |0i, |02, and |93. Motor terminal |0| is connected through line |94 to contact |02 and through jumper |95 to contact |20 of the control switch. Motor terminal |02 is connected through line |00 to contact |04 and through jumper |01 to contact |30 of the control switch. A

Motor terminal |03 is connected through lead to terminal |09 of magnetic contacter designated generally as |51. Terminal 200 of magnetic switch is connected through conductor 20| to movable contact |21 and through jumper 202 to movable contact |29. Terminal 200 of magnetic switch is connected through conductor 200 to movable contact 10| and through jumper 5 to movable contact |33. The electric power supply is connected to the magnetic switch through conductors 206, 201, 208 to terminals 209, 2|0 and 2|| respectively. The magnetic coll |01 is connected at one end to terminal 2|0 and its other end is connected through conductor 2l-2 to overload switch |64, thence through conductor 2|3 to movable contact |20 of the control switch. Contact |20 is arranged to engaged stationary contact |2| and the latter is connected to conductor 2 I4 to terminal 200 of the magnetic switch.

When the apparatus of Figs. 10 to 13 is actuated as above described by movement for example from mid outer position to inner FOR positions tory to admitting forward driving current to motor` I 50. No load current is admitted at this stage, however, since switch I? is still open. As'soon, however, as the control is permitted to assume the"FOR outer position contacts i2l-i2ii close energizing coil I8?v and closing switch ll. The knob M8 can then be released and it will be seliretaining in this position and motor -i Eil will continue to run in the forward direction. The only' movement ol which the control is capable in this position is an inward motion and as soon as this is executed switch ibi is opened while it-i3d and nilits remain in engagement. Switching from forward to reverse and vice versa or entry of reverse directly` from mid position will be readily understood to be likewise accomplished with power current admission or interruption controlled solely by switch It is 'to be understood that the motor control circuit as described in connection with Figs. lif, il, l2, ls and l5 is ci the sci-called two wire control and provides only7 no voltage release.

ontained within knob ilii is a hey controlled cylinder loci; its, having transversely extending holt il@ actuated by i'ii lholt itil is adapted to engage either oi slots i12 or When holt i'lii is in slot il?) as shown in Fig; 'il a siir.- able captive pin tit precludes normal inward movement ci' lnoob itt and thus effectively locksE the switch in either oi the on positions or in the olim position. By lodging the holt il@ in slot i'i pin iid is no longer held protected position and the switch is free to function in normal manner.

It is to be noted that the lool: device contained within the manually operable handle functions on the basis oi an axial displacement, namely within the handle is an element under the coutrol of' a key, which element is manually displaced and locked, and while in this position the switch cannot be turned to another position. As the control switch herein described is based upon an axial motion together with a rotary motion it is seen that the lock device is coordinated with the ,very motions oi the control switch. It is understood that this lock device may be used with any control switch which is provided with an operating mechanism which is pushed in to be turned.

While there has been herein described the utilization of the apparatus of this invention to accomplish motor reversal it will be apparent to those skilled in the art that the apparatus of this invention will be equally useful in cases where alternative circuits are to be selected for other purposes.

I claim:

1. In a switch adapted to select a plurality of circuits the combination comprising, a. shaft mounted for axial and rotative movement, means adapted to prevent rotative movement of said shaft except in a selected axial position, a plurality of circuit selecting contacts, means adapted to cause and maintain engagement of alternative groups of said circuit selecting contacts when said shaft is in selected rotative positions, a pair of control circuit contacts, and means adapted to cause engagement of the same when said shaft is in an axial position other than one in which it is capable of rotation.

' 2. In a switch adapted to select a plurality of circuits the combination comprising, a. shaft mounted for axial and rotative movement, means adapted to prevent rotative movement oi said -shaft except' in a selected axial position, a secchasers ond shaft mounted for rotative movement, means adapted to cause said second shaft to he rotated by saidiirst shaft independent of axial movement thereof, a plurality of circuit selecting contacts adapted to 'ne selectively engaged in alternative groups response to selective rotative positions of said second shaft, means preventing rotative movement of both shafts except when said hrst named shaft is in a selected axial position, and control contacts adapted to be engaged upon arial movement or said irst named shaft away from an axial position in which it is capable ci rotation.

3. In a switch'having an "ohm position and adapted to select a plurality oi circuits the combination comprising, a shaft mounted ior axial and'rotai've movement, means adapted to preclude rotation of said shaft except in. a selected axial position, a plurality oi? circuit selecting contacts, means adapted to cause and maintain engagement of alternative groups ci said circuit selecting contacts when said shaft is in selected rotative positions, said shaft having a rotative position none oi said circuit selecting contacts are engaged, control circuit completing means a pair oi contacts, and means adapted cause engagement or control circuit contacts when said shaft is an position other one in which it is capable ci rotation and an angular position other than a position which which none of said circuit selecting contacts are in engagement.

d. :in s. .tch adapted to select a plurality circuits the combination comprising, a shaft mounted for axial and rotative movement, means adapted preclude rotative movement of said shaft except in a selected axial position, a plurality oi circuit selecting contacts, means adapted to cause and maintain engagement of alternative groups of circuit selecting contacts when said shaft is in selected rotative positions, a control circuit means including pair of contacts, means adapted to cause engagement of said control contacts when said shaft is in an axial position other than one in which it is capable oi rotation, and locking means for locking said shaft in an axial Aposition in which rotation is precluded.

5. In a switching apparatus the combination comprising a plurality of stationary contacts, e. plurality of movable contacts arranged to selectively engage said stationary contacts, an operating member therefor adapted to cause selective engagement thereof capable of axial movement 'between a plurality of axial positions and capable of angular movement in some of said axial positions and prevented from angular movement in others of said axial positions, and locking means associated with said operating member adapted when locked to rigidly restrain said operating member in one of said axial positions in which rotary movement is prevented.

y6. In a switching apparatus the combination comprising a plurality of stationary contacts, a plurality of movable contacts arranged to selectively engage said stationary contacts, an operating member therefor adapted to cause selective engagement thereof capable of axial movement between a plurality of axial positions and capable of angular movement when in some of said axial positions and prevented from angular movement in others of said axial positions, a lock mounted upon and in alignment with said operating member having a locked position in which said operating member is rigidly restrained against axial movement when said operating member is in an 11 axial position in which angular is i pgevented.

7. In a switch adapted to select a plurality of circuits the combination comprising a rstgroup of contacts adapted to be engaged alternatively in sets, a separate set of control contacts, means movable rst to cause engagement of some of said disengagement of said cntrol contacts.

. f' references ase of record in the A me of this patent:

'* STATES PATENTS ber Name Date Briggs June 23, 1914 Johnson Sept. 8, 1925 Kageyama Deo. 2, 1930 Schiebeler Nov. 16, 1937 v Wickerham Apr. 15, 1941

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