US2295517A - Operating mechanism for electric switches - Google Patents

Description

Sept. 8, 1942. U R 2,295,517

OPERATING MECHANISM FOR ELECTRIC SWITCHES Filed March 17, 1941 3 Sheets-Sheet l as 33 a4 zz ZZ.

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az 3 I {a jgfb L g x w as I P 8, 1942- G. J. MEUER 2,295,517

OPERATING MECHANISM FOR ELECTRIC SWITCHES Fi led March 17, 1941 s Sheets-Sheet 2 Sept. 8, 1942. MEUER 2,295,517

OPERATING MECHANISM FOR ELECTRIC SWITCHES Filed March 17, 1941 3 Sheets-Sheet 3 O 50 (mi 9/ 3 75' 9a 9a 76 U" 1 Q as 61 Patented Sept. 8, 1942 OPERATING MECHANISMFOR ELECTRIC SWITCHES George" J. Meuer, Milwaukee, Wis., assignor to Cutler-Hammer, Inc., Milwaukee, Wis., a corporation of Delaware Application March 17, 1941, Serial No. 883,667

9 Claims.

This invention relates toimprovements in operating mechanisms for electric switches.

A primary object of the invention is to provide novel mechanical interlocking means for the operating elements of switches, involving the use of three pushbutton control elements to provide forward, stop and reverse control functions for an electric motor or the like, or to provide slow or fast speed or stop control functions as a starting and stopping control station for a two-speed motor.

Another object is to provide for attainment of the aforementioned and other control functions by use of switches of substantially standard form, but modified in respect of theoperating elements thereof to be associated with the. novel operating and interlocking elements of the control station as a whole.

Another object is to provide a novel control station of the three pushbutton type.

Another object is to provide a pushbutton control station having interlocking means for latching the switch parts in any one of a number of difi'crent circuit controlling positions.

Another object is to provide novel means for supporting and enclosing the switches and their associated operating mechanism to provide the control station.

Another object is to provide a switch interlocking mechanism the parts of which are of simple and inexpensive form whereby formation and assembly of said parts is facilitated.

Other objects and advantages of the invention will hereinafter appear.

The accompanying drawings illustrate certain embodiments of the invention which will now be described, it being understood that the embodiments illustrated are susceptible of modification in respect of certain structural details thereof without departing from the scope of the appended claims.

In the drawings,

Figure l is a vertical sectional view of a twospeed, across-the-line, manual starter for an alternating current motor, the insulating" base and cover elements of one of the two multi-pole, slow-break switches being shown in elevation, and both switches of the pushbutton station being shown in their normal circuit interrupting positions.

Fig. 2 is a fragmentary view, partly in section, similar to Fig. 1, but showing the left-hand pushbutton depressed and latched to efiect circuit closing operation of its associated switch, the

manner in which the right-hand pushbutton is restrained against depression thereof, pending momentary depression of the intermediate pushbutton, being likewise illustrated.

Fig. 3 is a fragmentary horizontal sectional View, on the line 3-3 of Fig. 1, one of the pushbuttons and its associated stop member being shown in dotted lines, to illustrate the form of the latter.

Fig. 4 is a fragmentary view, partly in elevation and partly in section on the line 4-4 of Fig. 1.

Fig. 5 is a perspective view, in separated relation, of certain of the interlocking and latching elements shown in Figs. 1 to 4, a fragment of the shank portion of the intermediate pushbutton being also illustrated.

Fig. 6 is a fragmentary view, partly in vertical section and partly in side elevation, quite similar to Fig. 1, but illustrating a slightly modified form of my improved operating and interlocking mechanism adapted to use with a pair or double-pole, single throw switches of the snap action type, both of the switches being shown in the off positions to which they are normally biased" by parts of the interlocking mechanism.

Fig. '7 is a view in side elevation, quite similar to Fig. 6, but showing the right-hand pushbutton depressed and latchedto retain its associated switch in circuit completing position, a fragment of the casing cover being shown in section.

Fig. 8 is a detail perspective view of one of the two latch bars employed. in the control station of Figs. 6 and 7.

Fig. 8 is a fragmentary vertical sectional view of a slightly modified form of the device illustrated in Figs. 6, 7 and 8.

Fig. 9 is a detail perspective view of one of the two combination interlocking and latching bars employed in the control station of Figs. 10 to 12, inclusive.

Fig. 10 is a view partly in side elevation and partly in vertical section illustrating a three pushbutton control station employing. a pair of multi-pole switches, each of which is of the double throw type without an off position, all of the pushbuttons being shown in their upper extreme positions.

Fig. 11 is a fragmentary elevational view of the device shown in Fig. 10, but showing the relative positions of certain of the switch parts and of the interlocking and latching elements associated therewith upon depression ofthe left-hand pushbutton, and

Fig. 12 is a fragmentary vertical sectional view, on the line |2|2 of Fig. 10.

Referring first to the pushbutton station shown in Figs. 1 to 5, the numeral |5 designates the lower or main body portion of an enclosing casing, which is preferably formed or fabricated from sheet metal to elongated substantiallly rectangular or box-like contour. A closure or cover member |8, which is likewise preferably formed of sheet metal, has a downwardly extending flange or skirt l6 which peripherally surrounds the upper end of the casing portion I5. Rigidly attached to the opposite ends walls |5 and |5 of portion l5 are lugs or brackets l5 and I which are respectively provided with tapped openings to receive the shanks of a pair of screws I! whereby the cover member I6 is removably secured to portion l5. The casing illustrated is of the surface mounting type, and accordingly the bottom wall |5 of portion I5 is preferably provided at suitably spaced points with a plurality of openings (not shown) to provide clearance for the shanks of screws for attachment of the casing to any suitable support. The aforementioned end walls l5 and I5 are provided with suitable knockouts, such as I5 and I5 which upon removal afford openings for entry and exit of a suitable cable or wires for proper electrical connection with the various terminals of the switch mechanism.

Permanently attached to the inner surface of cover member l6, as by means of a pair of metal eyelets I8, I8 is a yoke member or bracket I 9 which is provided with a flat portion I9 which is located in a plane parallel to and spaced inwardly from the cover member H3. Portion I9 is preferably provided at opposite edges thereof with upwardly angled ribs or flanges I9 and I9 which are adapted to strengthen portion l9 and to resist bending thereof in a transverse plane.

The switches employed in the control station of Figs. 1 to 5 are of the slow-break type adapted for the control of alternating current circuits, said switches as shown being of the character disclosed in Patent No. 2,133,545, granted Oct. 18, 1938, to A. -W. Krieger, and assigned to Cutler-Hammer, Inc., the assignee of the present application. As best illustrated at the left-hand side of Fig. 1 and in Fig. 4 hereof, said switches are of the three-pole type shown in Figs, 17 to 19 of said Patent No. 2,133,545. More specifically, each of the two like switches 29, 20 comprises a main insulating base portion 2|! which is provided with a recess 2!? opening to the upper surface thereof (Fig. 1), said recess being provided with two pairs of longitudinally alined barrier portions (such as shown at 20 and 20 to provide three pairs of longitudinally alined auxiliary recesses. Said auxiliary recesses are respectively provided with ledges offset inwardly and located in a common plane a substantial distance from the upper surface of base 2%. Positioned upon each ledge is a flat contact plate 2|, each of the plates 2| preferably having rigidly attached to the lower surface of its free end portion, as by spot-welding, a contact tip 2| of coin silver, or other high quality contact material. Plates 2| are rigidly secured in their respective positions by hollow metal members 22 whose shank ends are upset over said plates, as shown at 22 22 the flat heads 22 of which are of square or other polygonal contour to seat in correspondingly shaped recesses in the lower surface of base 2%, whereby the same act as wiring terminal members, in conjunction with the usual binding screws 23, which provide for bottom wiring of the switch mechanism.

Associated with and underlying each pair of longitudinally alined contact plates 2| is a bridging contactor 24 having attached to each end at the upper surface thereof the pair of contact tips 24*, 2%, formed of coin silver or the like, for cooperation with the respective pairs of con-- tact tips 2| 2| aforementioned. Each of the three bridging contactors 24 for each switch (only one of which contactors is shown in Fig. l) is normally biased upwardly, as by means of a coiled compression spring 25 individual thereto, to effect engagement of the contactor tips 24 24 with the tips 2|, 2| of the respective pair of stationary contacts associated therewith.

A molded insulating plunger 26, of the form shown in detail in Fig. 18 of said Patent No. 2,133,545, is adapted to seat against the upper surfaces of the three contactors 24 for support by the latter, the springs 25 tending to effect extreme upward movement of contactors 24, with consequent upward movement of plunger 23. Rotatable within a cavity 26 at the upper end of plunger 26 is a disk or cylinder 21, said cylinder being supported for rotation by a. pin 28, which seats downwardly within a pair of open pivotal bearings (not shown) formed in said plunger. The length of pin 28 and the form of plunger 26 are such that accidental lateral disassembly of the pin from cylinder 21 is positively prevented. The structural features just mentioned are shown (Figs. 8 and 10) and described in detail in my copending application, Ser. No, 347,600, filed July 26, 1940, for improvements in Operating mechanisms for electric switches.

Each switch 20 is also provided with a molded insulating cover member 20, of the form shown in greater detail at 19 in Figs. 8 and 10 of my aforementioned application, Serial No. 347,600. Thus each member 20 is provided with a pair of upwardly opening pivotal bearings (not shown) within which the opposite ends of a pin 29 are adapted to bear, said bearings being so formed as to positively prevent endwise displacement of said pin. Each pin penetrates an opening in and acts as a pivotal support for a switch contactor operating lever 30. The lever 30 of each switch is provided at its lower end with a cam surface 3|! which is adapted in one extreme position thereof to cooperate with cylinder 21 to effect depression of plunger 26, with consequent disengagement of the contactors from the stationary contacts of the switch, as indicated in respect of both switches in Fig. 1. As will be noted, although the two switches 20 are of identical size and construction they are reversely arranged relatively to each other, so that lever 30 of the left-hand switch must move clockwise to effect off positioning of its associated contactors, whereas lever of the right-hand switch is moved counterclockwise to effect off positioning of its associated contactors.

Levers 30 are normally jointly biased to the respective extreme positions thereof shown in Fig. 1 as by means of a pair of coiled tension springs 3|, 3|, the opposite looped ends of which are attached to the ends of a pair of pins 32, 32, in the manner best illustrated in Fig. 3. Said pins penetrate openings in and extend a substantial distance on each side of arms or extensions 30* 3|) formed integrally with the lever 30, 30, re spectively, whereby the aforementioned normally biased movements of said levers are effected.

integral angularly extending arms 38", 30 havingslightly enlarged ends 30 30, which are respectively adapted forinterlocking engagement with the-end walls of slots 33, 33 formed in the vertical shank portions 33', 33 of like metal members, the horizontal portion 33 33 of which are rigidly attached to the inner ends'of the respective end pushbuttons 34 and 35 of the control station, as by means of self-tapping screws 36, 33 the shanks of which take into preformed recesses in the respective buttons. Said horizontal portions 33 33 are preferably of rectangular contour, and the same fit into recesses of corresponding width formed in the lower surfaces of the respective pushbuttons 34 and 35 in a substantially flush relationship to said lower surfaces, thus preventing rotation of said pushbuttons relatively to the respective members 33.

Interposed between the head of each screw 36 and its associated portion 33 of member 33 is a substantially rectangular metal member 31, the purpose of which is to positively limit the degree of upward movement of the respective pushbutton 34 or 35 associated therewith, by engagement of said member with the lower or inner surface of the cover member l6 of the casing. Although the pushbuttons 34 and 35 may be of identical form, they are preferably molded in different molding dies, so that different legends may be formed in the upper surfaces thereof, as, for instance, the respective legends For. and Rev, or the respective legends Fast and Slow, depending upon the particular use to be made of the pushbutton station. In practice, the lettering or legends just mentioned are in the form of depressions in the respective pushbuttons, which depressions are then filled with a suitable enamel of a color contrasting with the color of the material from which the pushbutton is molded, whereby the legibility of the legends is substantially increased.

In practice it is desirable to positively prevent simultaneous depression of pushbuttons 34 and 35 to an extent sufficient to effect completion of the respective circuits ot be controlled thereby. Accordingly I provide a pair of relatively long substantially rectangular interlocking links or bars 38, 38 (see Fig. each of which i provided adjacent to the respective ends thereof with a pair of slots 38 --and 38 of predetermined like lengths through which the aforementioned pins 32, 32 respectively extend. The arrangement is such that when the parts of both switches 20, 20 are in their circuit interrupting positions the pins 32, 32 will be located adjacent to the inner ends of the respective pairs of slots 38 and 38 as shown in Fig. 1. However, upon depression of pushbutton 35 toward its lower extreme position, as shown in Fig. 2, the left-hand pin 32 will first move to the left-hand end of the slots 33 of members 38, and continued movement of said pin toward the left will result in bodily movement of bars 38, 38 toward the left, until the right-hand ends of slots 38 38 are closely adjacent to the right-hand pin 32 (Fig. 2).

Such movement of the left-hand pin 32 toward the left away from the right-hand pin 32 will, of course, increase the tension of springs 3|, 3|. The springs 3|, 3| are sufficiently powerful to overcome the resistance to clockwise movement of the lever 30 of the left-hand switch 20 under these conditions, such resistance being due to the action of the switch springs 25 acting through plunger 26 and cylinder 21 upon the cam surface 30* of the lever, sothat upon manual release of said pushbutton 35 (in the. absence of any additional elements) the left-hand switch lever would be rotated clockwise from the circuit completing position thereof shown in Fig. 2 to the initial circuit interrupting position thereof shown in Fig. 1, the end 30 of the arm 30 of lever 30 acting simultaneously to return pushbutton 35 to its upper extreme position shown in Fig. 1.

As will be apparent from consideration of Fig. 2, due to take-up of the lost motion between the two pins 32 and the two sets of slots 38 and .38 the right-hand pushbutton 34 cannot be depressed to a sufficient degree to effect circuit completing: operation of its switch mechanism until the parts of the left-hand switch have been moved to circuit interrupting position, such movement also resulting in upper extreme positioning of pushbutton 35.

In like manner, with the aforedescribed parts in the respective positions thereof shown in Fig. l, upon depression of pushbutton 34 to its lower extreme position to efiect circuit completing operation of its switch, the right-hand pin will be moved toward theright to first tak up the lost motion afforded by slots 38*, 38 and continued movement in said direction will effect bodily movement of links 38, 38 to take up th lost motion between slots 38 38 and the left-hand pin 32'. The links 38 thus act to positively insure against circuit completing operation of both switches. 2 0 simultaneously.

With the arrangement thus far described the circuit controlled by each switch 20 would be completed only so long as its associated pushbutton 34 or 35 were held manually in its lower extreme position. In practice it is desirable to insure automatic retention of either of the switches 20 in its circuit closing position as an incident to momentary depression of its associated pushbutton. Accordingly I provide latching means comprising a pair of like flat punched sheet metal members 39, 39 which are arranged in parallel alinement with each other between the aforementioned pair of links 38", 38. The form of members 39 is best illustrated in Fig; 5, and the same are provided at points offset inwardly from the respective ends thereof with upwardly opening notches 39 and 39 against the inner vertical walls of which the pins 32' are adapted to abut in the initial position of the switch parts, as shown in Fig. l. The outwardly extending walls of notches 39 and 39 are angled upwardly to a predetermined degree and lead to the vertical walls of notches 39 and 33 closely adjacent to the respective ends of said members 39.

Members 39are provided substantially centrally thereof with circular openings 39 which are alined with an opening 40 in a metal shank member positioned therebetween. A headed rivet 4 l loosely penetrates the alined openings 39 40 and 38 and has its shank end upset, as best illustrated in Fig. 3, thus providing a pivotal connection between member 40 and members 39"; Shank member 40 has a notched head portion 43 embedded or molded as an insert within a pushbutton 42, as best illustrated in Fig. l. A

Member 40 has a reduced lower end portion 40, thus providing a pair of horizontally alined shoulders 40 and 40, Fig. 5. Portion 48 extends downwardly through an opening 19 (Figs. 1 and 4) in a downwardly ofiset portion [9 of flat portion l9 aforementioned. Surrounding portion 40 and interposed between portion I9 and the notched lower edge portions 39 of members 36 is a coiled compression spring 43 which acts to bias members 39, member 40 and pushbutton 42 toward their upper extreme positions. As a result of this bias, it will be noted from Fig. 2 that upon counterclockwise movement of the left-hand switch lever 30 (as an incident to depression of pushbutton 35) the left-hand pin will ride out of the left-hand notches 39 and into alinement with the left-hand notches 39 of members 39, whereupon spring 43 acts to effect movement of the vertical walls of the last mentioned notches into latching or looking relationship to said left-hand pin 32.

By this arrangement the left-hand switch 20 will be retained in its circuit completing position and pushbutton 35 will also be retained in its depressed position to afford an indication of the condition of the controlled circuit. Also, as will be apparent from Fig. 2, the pushbutton 34 cannot be depressed to effect circuit completing operation of the right-hand switch 20 pending circuit interrupting operation of the left-hand switch 20 with consequent return of pushbutton 35 to its upper extreme position. Such locking of pushbutton 34 against depression thereof is due to the fact that the lost motion between the two pins 32 and the outer end walls of the pairs of slots 38 38 has been taken up; the left-hand pin 32 abuts against the vertical walls of the pair of notches 39 whereas the pushbutton 42 and its shank member are substantially limited to reciprocating movement in a vertical plane, thus preventing any substantial degree of displacement of pivot pin 4| out of said vertical plane.

However, upon momentary depression of pushbutton 42 the vertical walls of the pair of notches 39 will be moved downwardly out of the plane of travel of the left-hand pin 32, so that the latter is freed to move toward the right (under the bias of springs 3|) to the position thereof shown in Fig. 1, the lever 30 of the left-hand switch 20 being simultaneously rotated by said springs to return said switch to its normal circuit interrupting position shown in Fig. 1. Thereafter either pushbutton 35 or 34 may be depressed to effect circuit completing operation of its associated switch, it being understood that such switch will be automatically latched in circuit completing position and that the other pushbutton be positively restrained against depression pending momentary depression of the stop pushbutton 42, as aforedescribed.

If the control station illustrated in Figs. 1 to 5 is utilized for reversing control of a motor, the end button 35 may have the legend For. applied thereto; the other end button 34 may carry the legend Rev, the intermediate button 42 being marked Stop. On the other hand, if the control station is used in conjunction with a twospeed motor the buttons 35 and 34 may be marked Fast and Slow, respectively; the button 42 carrying the legend Stop. The three-pole switch illustrated in Figs. 1 to 5 has a rating of two horsepower in the control of a polyphase motor, at 440 to 550 volts.

The switches 20 of Figs. 1 to 5 are rigidly secured to the aforementioned flat portion I!) of bracket l9 as by means of their respective pairs of diagonally arranged securing screws, one screw, l9 and H of each of the respective pairs being illustrated in Fig. 3. As shown in Fig. 1, the downwardly offset portion H! has ends I9 and I9 of approximately semicircular form to fit within vertical grooves 20 2|! of corresponding form in horizontal cross section provided in the adjacent ends of the insulating cover members 20 of switches 20. In like manner, portion I9 is provided with downwardly angled integral lugs (one of which is shown at I9 at the left-hand end of Fig. 1) to fit within the like grooves 20 at the respective outer ends of said cover members. Such engagement of the lugs and grooves just mentioned serves to insure positive tandem alinement of the two switches 20 with respect to each other when the parts are completely assembled.

With reference to Figs. 1 and 5, it is to be understood that the three terminal screws 23 at the outer ends of the respective switches 20 are adapted for attachment of circuit wires, whereas the longitudinally alined terminal screws 23 at the adjacent ends of switches 20 are electrically connected with each other, as by means of three like plates or bus members 44. It is accordingly only necessary to attach circuit wires by one of the two screws 23 associated with each bus bar 44 to provide the proper electrical connections common to the two switches 20. Bus members 44 are employed in both the reversing and two-speed control types of pushbutton sta tions. Other wiring arrangements for the switch mechanisms may, of course, be employed if desired.

The three pushbutton reversing and/or twospeed motor control station illustrated in Figs. 6, 7 and 8 is functionally and operatively similar to that aforedescribed, but is modified in respect of certain structural details to provide for use of two like double-pole snap switches of the character disclosed and claimed in my prior patents, No. 1,889,259, granted Nov. 29. 1932, and No. 1,977,078, granted Oct. 16, 1934.

Thus the switches 50 and 5| may be identical with each other in all respects, but the same are reversely arranged in tandem or end-to-end relationship with each other when mounted upon the fiat portion 52 of a yoke or bracket 52, the ends of which bracket are rigidly secured to the inner surface of the aforedescribed cover member 6, a fragment of which is shown in Figs. 6 and 7. Portion 52 of the bracket is located in inwardly offset parallel relationship to the cover member l5 and the switches 50 and 5| are each rigidly attached thereto, as by means of a pair of screws 53, 53, in the manner best illustrated at the left-hand end of Fig. 6.

Each switch 50 and 5| comprises a molded insulating base 54, a flat punched insulating cover member 55, and a punched and stamped sheet metal cover member 56 to which a metal bushing 57 is rigidly attached. The initially closed upper end of each bushing is provided with a kerf 5| (as shown at the lefthand end of Fig. 6) to provide oscillatory clearance for the three arms 58*, 58 and 58 of a lever which is pivotally connected with the bushing, as by means of a pin 59. The arm 58 of each lever extends downwardly through the bushing for cooperation with the snap actuating elements of the switch, as disclosed in my prior patents aforementioned. The arm 58 of each lever is provided adjacent to its free end with an opening 58 which is substantially larger in diameter than the pin 60 which extends therethrough.

Each pin 60 is headed and the shank thereof passes transversely through openings provided in the parallel downward extensions 6F and SI awe-517 of a pushbutton 6 I, each lever arm 58* being positioned between said extensions. Positioned within a suitable cavity in each pushbutton 6| and adapted to press downwardly at all times against the end of arm 58' is a coiled compression spring 62, which also acts to at all times bias the pushbutton 6| upwardly to a predeterminded degree relatively to the lever arm 58*, This arrangement provides the necessary amount of lost motion between pin '60 and lever arm 58 and at the same time avoids any undesirable looseness or rattling of the pushbutton 6|. Cover member I is provided with upstanding cylindrical flanges l6 and It to assist in limiting the pushbuttons 6| to reciprocating movement in a straight line.

The arms 58 of the respective levers are provided in their ends with openings through which the pair of pins 32 aforedescribed are adapted to pass, said pins also extending through longitudinally extending slots 63 and 63 in a pair of like elongated rectangular members 63 (only one of which is shown in .Figs. 6 and '7), said members 63 being structurally equivalent to the members 38 aforedescribed.

Positioned between members 63 are a pair of like latch members 64, only one of which is visible in Figs. 6 and '7. The form of members 64 is best illustrated in Fig. 8, the same being functionally like and structurally similar to the members 39 aforedescribed. Positioned between the pair of members 64 is the metal shank 65, which has its upper end (not shown) embedded or molded in the center pushbutton 65. A headed pin 61 has its shank penetrating alined openings 6 3 (Fig. '8) in members 64 and in shank '65 to pivotally connect said three members to each other.

Members 64 are provided adjacent opposite ends thereof with notches or cut-away portions producing vertical shoulders 64 and 65* against which the pins 32, 32 are drawn by the pair of tension springs 3| (see Fig. 6) when both switches 58 and 5| are in circuit interrupting position, as shown in Fig. 6. Members 64 are also notched at points more closely adjacent their opposite ends to provide vertical shoulders 64 and 64 to alternately cooperate with the ends of the respecti'e pins 3| when the right-hand or lefthand pushbutton 6| is depressed, as illustrated by the depressed position of the right-hand pushbutton in Fig. '7. Cover member IB is provided with an upstanding circular flange I6 to assist in guiding pushbutton 66 and limiting the same to reciprocating movement in a straight line.

With the right-hand switch 5| in circuit completing position as shown in Fig. '7 the left-hand pushbutton 6| cannot be depressed to effect simultaneous circuit completing positioning of the left hand switch 50, the opposite ends of the right-hand pin 32 cooperating with the shoulders 64 on latch members 64 to prevent such movement of the parts. As will be noted the reduced lower end of the shank 65 extends downwardly through a flanged opening 52 in member 52 to I of a pair of metal eyelets l8, l8.

ders 64 will be displaced downwardly out of engagement with right-hand pin 3| which is then drawn by springs 3| to its normal position shown in Fig. 6, with consequent interruption of the circuit controlled by the right-hand Switch 5|. Thereafter either the left-hand or right-hand pushbutton 6| may be depressed, and latched automatically in depressed positiomto effect closure of the circuit controlled by its respectively associated switch 50 or 5|.

The usual end wiring terminals 69 of the switches have associated therewith the substantially L-shaped members 69 and 69, and attached to said terminals by screws 69, the members 68 having portions underlying portions of the members 89 between the two switches, whereby six bottom-wiring binding screws 23 of usual form may be associated with the two switches.

Bracket 52 is permanently attached to the inner surface of cover member It as by means In practice the fiat'portion 52 of bracket 52 is provided with longitudinally extending ribs, 52 adjacent opposite edges thereof to increase the strength and to resist transverse bending or deformation thereof. The center pushbutton 65 is preferably provided with the legend Stop and the end pushbuttons 6|, 6| are provided with alternative legends. as described in connection with Figs. l to .5, according to the particular character of control functions contemplated.

The switch illustrated in Figs. 6 to -8 has a rated capacity of one-half horsepower at or 230 volts, direct current.

The modified form'of pushbutton control station illustrated in Fig. 8 is in many respects like that of Figs. 6 to 8, and certain parts identical with those of Figs. 6 to 8 may be employed, .the same saving been given like numerals of reference. The device of Fig. 8 may be operated to perform the same functions as the device of Figs. '6 to 8; and in addition the same is so constructed as to provide for alternate depression of the end pushbuttons 6|, 5 l, subsequent to depresion of one of the latter, without necessitating momentary depressionof the center push button 10, which in this device is of special form.

More particularly, the pushbutton I0 is pro vided at its lower end with an annular flange 10 which is adapted to underlie the inner surface of the cover member IE, to limit the degree of outward displacement of said pushbutton. Pushbutton 10 is provided with a recess "lo opening to its lower end, said recess being of a width (transversely with respect to cover member l6) which is only slightly greater than the thickness of a metal member H whose upper end portion is at all times positioned within said recess. Re-

cess 10 has a dimension (longitudinally with respect to cover member l6) which is substantially greater than the width of that portion of member H which projects upwardly thereinto; thus providing for a predetermined degree of oscillatory movement of member II with respect to said pushbutton 10. Recess 10 extends upwardly beyond the upper end of member H to such a degree as to permit depression of pushbutton 10 at any time without interference by the member 1|.

' Member -'II is pivotally connected to a pair of latch members 64 (which are preferably identical with the corresponding members described in connection with Figs. 6 to 8) as by means of the pivot pin 61 aforedescribed. Positioned on opposite sides of members 64 are a pair of members (one of which is illustrated and designated by the numeral 63*). The members 63 are substantially identical in form with the members 63 described in connection with Figs. 6 to 8; but each member 63 is provided in its upper edge with a notch 63 the purpose of which is to provide for downward or unlatching movement of the pair of members 64 without interference by the members 63*, as will be obvious.

As will be noted from Fig. 8, the other parts of the control station (including the various elements of the two switches, not illustrated) correspond with those illustrated in Fig. 7. The parts of the control station of Fig. 8 function in the manner described in connection with Figs. 6 to 8 to prevent simultaneous depression of the end pushbuttons 6|, 6|, whereby circuit completing operation of both switches simultaneously is positively prevented.

On the other hand, after circuit completing positioning of the corresponding switch by depression and latching of the lower pushbutton 6|, it will be apparent that upon subsequent depression of the upper pushbutton 6| the elements will function to effect interruption of circuit by the switch associated with the lower pushbutton 6|, with consequent return of the lower pushbutton 6| to its upper extreme position, and thereafter the switch associated with the upper pushbutton 6| of the station will be operated to its circuit completing position, the upper pushbutton 6| being retained in its fully depressed position. Under these conditions, it is to' be noted that the lower pin 32 will be maintained in engagement with the walls 64 of the end notches of members 84, and the retention of the parts in the respective positions thereof last mentioned will result from application of the force of spring 68 to pivot pin 6'! at an angle upwardly with respect to the horizontal center line of pushbutton 10, as shown in said Fig. 8 the member having been swung or oscillated to the position thereof shown in dotted lines at under these conditions.

On the other hand, regardless of whether the lower or upper pushbutton 6| is depressed the same may be unlatched for return thereof to its upper extreme position, with consequent interruption of the circuit controlled by its respective switch, by momentarily depressing the center pushbutton 70.

Assuming that both of the end pushbuttons 6|, 6| are in their respective upper extreme positions; if the upper pushbutton 6| is depressed, the upper pin 32 will be drawn upwardly against the bias of the pair of springs (3|, not shown in Fig. 8) until the walls of end notches 54 of members 64 are free to move into latching engagement with the ends of said pin, under the bias of spring 68, thus effecting retention of the switch associated with the upper pushbutton 6| of the station in circuit completing position. If the lower pushbutton 5| is then depressed, prior to momentary depression of the center pushbutton 10, the members 64 will be maintained in latching relationship to the upper pin 32, but the members 63 and 64 will be moved bodily downward to effect circuit interruption by the switch associated with the upper pushbutton 6| and subsequent completion of circuit by the switch associated with the lower pushbutton 6|, the member being tilted to the position thereof shown at 1| whereby the spring 68 will act to maintain the switch parts in the various posltions thereof last mentioned.

The relationship of the recess 10 in pushbutton 10 to the member H is such that rotation of pushbutton I0 is positively prevented, thus insuring proper positioning of the legend (such as Stop) which may be applied thereto.

The pushbutton station illustrated in Fig. 8 is of advantage in those installations wherein it is desirable to provide for reversal of a controlled motor by plugging; inasmuch as the reverse circuit connections may be completed almost simultaneously with the moment of interruption of the circuit connections previously obtaining.

The three pushbutton control station illustrated in Figs. 9 to 12 is adapted to employ certain parts identical with those illustrated in Figs. 6 to 8, and such parts have been given like numerals of reference. On the other hand, the device of Figs. 9 to 12 is adapted for performance of the additional function described in connection with Fig. 8; namely, enabling depression of the end pushbuttons 6|, 6| alternately to effect the required operation of both switches, without necessitating operation of the center pushbutton 66 in each instance. Here, as in Fig. 8 however, the center pushbutton |5|i may be momentarily depressed after depression of either of the end pushbuttons 6|, 6| to insure upper extreme positioning of both of the latter, with consequent interruption of both of the circuits controlled by the respective switches.

The two switches 15 and 16 are preferably of like form, and are mounted in reverse relationship to each other (in respect of their operating levers 11 and 18 as by means of pairs of eyelets 19, 19) to the flat portion 52 of the supporting bracket 52. Each of the switches 15 and 16 is of the double-throw type, without an intermediate oil position, and the same may be assumed to be of the three-pole type. Switches of this character are disclosed in the copending application of Alvin W. Krieger, filed Nov. 16, 1940, Serial No. 365,907, attention being particularly invited to Fig. 5 of the drawings of said Krieger application. It is to be understood, of course, that the switches 15 and 16 may be modified (by omission of one or two sets of stationary and movable contact members) to selectively provide switches of the two-pole or single-pole type.

As will be understood from consideration of Fig. 10, the arrangement is such that with both end pushbuttons 6|, 6| in their upper extreme positions the three tiltable contactors (one of which is shown at in Fig. 10) of each switch are engaged with the outer stationary contacts, one of which is shown at 8|. In practice the switches 15 and 16 will be so wired as to provide, under the conditions just mentioned, for interruption of both the Forward and Reverse" circuits, or the Fast and Slow speed circuits of the controlled motor, according to the characteristics of the particular installation.

If the left-hand end button 6| is then depressed (as shown in Fig. 11) the three contactors 80 of the left-hand switch 15 will be tilted into engagement with the inner stationary contacts of said switch, one of said contacts being shown at 82, the contactors of the other switch 15 remaining in engagement with their outer stationary contacts (not shown). This may be assumed to provide for either Forward or Fast speed operation of the controlled motor (according to the particular installation).

The left-hand pushbutton 6| will be retained ments of switches 15 and I6 is believed to be apparent, attention being invited to the aforementioned Krieger application, Ser. No. 365,907,

in its depressed position and the right-hand pushbutton 6| will be held in its upper extreme position by the action of a pair of like combined interlocking and latching members 83, 83, one of which is shown in detail in Fig. 9. As shown, members 83 are each provided at the right-hand end thereof with a circular opening to freely accommodate the right-hand pin 32. Said members are each further provided at the other end thereof with a substantially L-shaped slot, whose horizontal portion is designated 83 and whose vertical downwardly extending portion is designated 83. The slots in members 183 .are adapted to accommodate the left-hand pin 32. Pins 32 are respectively pivotally connected with .the arms ll and 18 of levers I1 and 18, the springs 3|, 3| biasing said pins, said levers and their associated parts to the relative positions thereof shown in Fig. '10.

With the parts in the respective positions thereof shown in Fig. 10, upon depression of left-hand pushbutton 6| the left-hand pin will be drawn toward the left along portion 83 of each slot until it registers with the vertical portions 83 of said slots, whereupon the spring 58 in its upward bias against pin 85, which is in turn engaged with the lower edges of members 93, causes upward tilting of members 83 to the position thereof shown in Fig. 11. This latching action results in interlocking the two end pushbuttons 6 I, 6| to positively restrain the same against movement independently of each other. Similarly, with the parts as shown in Fig. 10, the same interlocking action would result from depression of the right-hand pushbutton switch 6|, inasmuch as the right-hand pin 32 would draw the members 83 bodily toward the right until the vertical portions 83 of .the notches were free to move upwardly, under the bias of spring 68, to effect the interlocking engagement aforementioned.

As will be understood, such interlocking engagement of the vertical portion 83 of the slots with the left-hand ,pin 32 will be maintained (see Fig. 11) during subsequent depression of the end pushbuttons 6|, 6| alternately, so that mere depression of that pushbutton 6| which happens to be in its upper extreme position will eifect interruption of the circuit which is then completed and substantially simultaneously effect completion of the circuit which is then interrupted. On the other hand, if either of the circuits has been completed by depression of one or the other of the pushbuttons 6|, 6|, the same may be interrupted at any time (thus insuring interruption of both circuits) by momentarily depressing the center 'pushbutton 66 which results in depression of members 83 to effect disengagemento-f the vertical portions 83 of the slots from the left-hand pin 32, whereupon the springs 3| will act to bring that pin 32 which has been last moved to the normal position thereof shown in Fig. 10.

Pin 85 is attached by a drive fit (see Fig. 12) within an opening in a shank member 86, the upper end of which is molded or embedded within the body of center pushbutton 66.

As shown, the levers l1 and 18 are pivotally attached to pairs of brackets 81, 81, as by means of pivot pins 88, said brackets being in turn attached to the metal cover plates 89 of the switches. The lower ends of levers l1 and 18 are forked, as shown at 'll and 18 for cooperation with the oscillatable insulating actuating members of the switches, one of which members is shown at 90 in Fig. 10. The operation of the "other elefor a detailed description of such switches. Although I have shown the switches 15 and I6 equipped with solder type terminal members 9| and 92, it is to be understood that other forms of wiring terminal elements may be employed if duplicate interlocking and latching elements in the other devices illustrated, it will be apparent to thoseskilled in the art thatsatisfactory results may be obtained by employment of single elements of the character illustrated, in which case the respective elements would preferably :be

formed from sheet metal of substantially greater thicknesses than those illustrated.

What I claim as new and desire to secure by Letters Patent is:

1. As an article of manufacture, a manually operable switch assembly of the pushbutton type comprising, a metal supporting member having a substantially flat portion, a pair of multi-pole switches of like form secured to said flat portion, each of said switches having a pivoted operating lever extending forwardly beyond the front face of said flat portion, a pushbutton pivotally connected with each lever in offset relation to the point of pivotal support of the latter, means comprising a coiled tension spring having its opposite ends attached to said levers at points offset from the points of apivotal support thereof to normally bias each of said pushbuttons to a given extreme position forwardly of the front face of said flat portion, means comprising a metal member pivotally attached to each of said levers to positively prevent simultaneous depression of said pushbuttons to their inner extreme positions, means includlnga pivotally supported and springbiased latch member operable automatically to retain either of said pushbuttons in its inner ex treme position when depressed, a third pushbutton :pivotally attached to said latch member whereby the former is normally biased to its outer extreme position, said third pushbutton being adapted when depressed to effect release of either of said other pushbuttons for movement of the latter under the bias of said tension spring to the forward extreme position thereof, for the purpose set forth, and a cover member attached to said supporting member in a plane parallel to and spaced forwardly from the latter and adap ed to conceal all of the switch parts except the cylindrical upper end portions of said pushbuttons, said cover member having openings formed therein to accommodate said cylindrical upper end'portions of the respective pushbuttons and to restrict at least the two first mentioned pushbuttons to 'reciprocatory movement in a substantially straight line.

2. As an article of manufacture, a manually operable switch assembly of the pushbutton type comprising, a supporting member having a sub stantially fiat portion, a pair of switches of like form secured to said fiat portion, each of said switches having a pivoted operating lever extending forwardly beyond the forward face of said fiat portion, a pushbutton pivotally connected with each lever in offset relation to the point of pivotal support of the latter, spring means associated with said pushbuttons to normally bias each of the same to a given extreme ,position forwardly of the front face of said flat portion, means comprising at least one tie member having a pivoted lost motion connection with each of said levers to positively prevent simultaneous depression of said pushbuttons to their inner extreme positions, and means comprising at least one spring biased latch member common to said levers and operable automatically to retain either of said pushbuttons in its inner extreme position.

3. As an article of manufacture, a manually operable switch assembly of the pushbutton type comprising, a supporting member having a substantially flat portion, a pair of switches of like form secured to said flat portion, each of said switches having a pivoted operating lever extending forwardly beyond the forward face of said flat portion, a pushbutton pivotally connected with each lever in offset relation to the point of pivotal support of the latter, spring means associated with said pushbuttons to normally 'bias each of the same to a given extreme position forwardly of the front face ofsaid flat portion, means comprising at least one tie member having a pivoted lost motion connection with each of said levers to positively prevent simultaneous depression of said pushbuttons to their inner extreme positions, means comprising at least one spring biased latch member common to said levers and operable automatically to retain either of said pushbuttons in its inner extreme position, and means comprising a third pushbutton operatively connected with said latch member intermediate the ends of the latter, said last mentioned pushbutton when manually depressed being adapted to render said latch member inefiective with respect to either of said levers.

4. As an article of manufacture, a manually operable switch assembly of the pushbutton type comprising, a supporting member having a substantially fiat portion, a pair of switches of like 1 form secured to said flat portion, each of said switches having a pivoted operating lever extending forwardly beyond the forward face of said flat portion, a pushbutton pivotally connected with each lever in offset relation to th point of pivotal support of the latter, spring means associated with said pushbuttons to normally bias each of the same to a given extreme position forwardly of the front face of said flat portion,

means comprising at least one tie member having a pivoted lost motion connection with each of said lovers to positively prevent simultaneous depression of said pushbuttons to their inner extreme positions, means comprising at least one spring biased latch member common to said levers and operable automatically to retain either of said pushbuttons in its inner extreme position, means comprising a third pushbutton having a pivoted driving connection with said latch member intermediate the ends of the latter, whereby said last mentioned pushbutton is normally held in its forward extreme position under the bias of said latch member, and said last mentioned pushbutton when manually depressed being adapted to momentarily render said latch member inefiective to retain either of said first mentioned pushbuttons in its inner extreme position.

5. In a motor control station of the pushbutton type, in combination, an enclosing casing comprising a recessed body member and a cover member, a metal bracket secured to the inner surface of said cover member and having a flat portion spaced inwardly from and parallel to said inner surface, a pair of electric switches of like construction attached to the inner surface of said flat portion, each of said switches including a pivoted operating lever at least a portion of which is located between the outer surface of said flat portion and said cover member, a single pushbutton pivotally connected with each of the respective levers in ofiset relation to the point of pivotal support of the latter, spring means associated with said pushbuttons to normally bias each of the same to its outer extreme position, means including a link having a lost motion connection with each of said levers while positively insuring against simultaneous depression of said pushbuttons to their respective inner extreme positions, means including a spring-biased latch common to said levers and operable automatically to effect retention of either of said pushbuttons in its inner extreme position, a third pushbutton adapted when depressed momentarily to effect release of either of the first mentioned pushbuttons retained thereby, said cover member having openings 'formed therein to accommodate said three pushbuttons and to limit the two pushbuttons first mentioned to reciprocating movement in a straight line, and means for rigidly but removably attaching said cover member to said body member.

6. In a motor control station of the pushbutton type, in combination, an enclosing casing comprising a recessed body member and a cover member, a metal bracket secured to the inner surface of said cover member and having a flat portion spaced inwardly from and parallel to said inner surface, a pair of electric switches of like construction attached to the inner surface of said flat portion, each of said switches including a pivoted operating lever at least a portion of which is located between the outer surface of said flat portion and said cover member, a single pushbutton pivotally connected with each of the respective levers in offset relation to the point of pivotal support of the latter, spring means associated with said pushbuttons to normally bias each of the same to its outer extreme position, means including a link having a lost motion connection with each of said levers while positively insuring against simultaneous depression of said pushbuttons to their respective inner extreme positions, means including a spring-biased latch common to said levers and operable automatical- 1y to effect retention of either of said pushbuttons in its inner extreme position, a third pushbutton adapted when depressed momentarily to effect release of either of the first mentioned pushbuttons retained thereby, said cover member having openings formed therein to accommodate said three pushbuttons and to limit all of said three pushbuttons to reciprocating movement in a straight line, and means for rigidly but removably attaching said cover member to said body member.

'7. In a pushbutton operated switch mechanism, a first pushbutton, a pivoted switch lever having an operative connection therewith, a set of contacts adapted to be closed upon pivotal movement of said lever as an incident to depression of said pushbutton to effect completion of an electric circuit, a second pushbutton, a second pivoted switch lever having an operative connection with the latter, a second set of contacts adapted to be closed upon pivotal movement of said last mentioned lever as an incident to depression of said second pushbutton to effect completion of a different electric circuit, means including a metal member mechanically connected to said levers jointly to positively restrain said pushbuttons against depression thereof simultaneously to thereby insure against completion of more than one of said electric circuits at a time, spring means common to said levers and said pushbuttons to normally bias the latter jointly toward their upper extreme positions, thereby tending to interrupt both of said electric circuits, means including a spring-biased latch-bar common to said levers and said pushbuttons to latch each of the latter in its lower extreme position when depressed selectively, and means comprising a third pushbutton positioned between and in parallel relationship to the other pushbuttons, said third pushbutton being associated with said spring biased latch-bar and adapted when momentarily depressed to effect unlatching of said first or second pushbutton if depressed, whereby both of said electric circuits are interrupted, said third pushbutton and its associated parts comprising the sole means for controlling and effecting interruption of either of said electric circuits when completed.

8. As an article of manufacture, a manually operable switch assembly of the pushbutton type comprising, a substantially flat supporting member, switch mechanism secured to said supporting member, actuating means for said switch mechanism comprising a pair of pivoted levers and opposite end pushbuttons having positive driving connections therewith respectively, a third pushbutton positioned between and in parallel relationship to said end pushbuttons, spring means common to said end pushbuttons to normally bias each of the same to a given position forwardly of the front face of said supporting member, means including a metal tie-bar mechanically connected to said levers to positively prevent simultaneous depression of said end pushbuttons to their inner extreme positions, and spring-biased means including a latch-bar common to said levers and operable automatically to retain either of said end pushbuttons in its inner extreme position when depressed, said last mentioned means also acting to normally bias said third pushbutton to a given position forwardly of the front face of said supporting member.

9. As an article of manufacture, a manually operable switch assembly of the pushbutton type comprising, a substantially flat supporting member, switch mechanism secured to said supporting member, actuating means for said switch mechanism com-prising a pair of pivoted levers and opposite end pushbuttons having positive driving connections therewith respectively, a third pushbutton positioned between and in parallel relationship to said end pushbuttons, spring means common to said end pushbuttons to normally bias each of the same to a given position forwardly of the front {face of said supporting member, means including a metal tie-bar mechanically connected to said levers to positively prevent simultaneous depression of said end pushbuttons to their inner extreme positions, spring-biased means including a metal latch-bar common to said levers and operable automatically to retain either of said end pushbuttons in its inner extreme position when depressed, means including a pivotal connection between said latch-bar and said third pushbutton whereby upon momentary depression of the latter either of said end pushbuttons is released for automatic return to the aforementioned normally biased position thereof, and means including said pivotal connection between said third pushbutton and said latch-bar to positively prevent depression of one of said end pushbuttons after depression of the other of the same pending momentary depression of said third pushbutton, for the purpose set forth.

GEORGE J. MEUER.

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