US2885905A - Detachable lever locking devices for electric switches - Google Patents

Description

R. E. LARKlN May 12, 1959 DETACHABLE LEVER LOCKING DEVICES FOR ELECTRIC SWITCHES 3 Sheets-Sheet I 1 Filed Feb. 15, 1956 a a M? an an 1 I W u m Nw fl -II n l 8 5% nu I 7 0M M2 R. E. LARKIN DETACHABLE LEVER LOCKING DEVICES FOR ELECTRIC SWITCHES Filled Feb. 15, 1956 I5 Sheets-Shqet 2 May 12, 1959 R. E. LARKIN 5 5 DETACHABLE LEVER LOCKING DEVICES FOR ELECTRIC SWITCHES Filed Feb. 15, 1956 5 Sheets-Sheet 3 66 IHA'" II- 67 1 III/I IA- IHIII' United rates Patent DETACHABLE LEVER LOCKING DEVICES FOR ELECTRIC SWITCHES Robert E. Larkin, Milwaukee, Wis, assignor to Cutler- Hammer, Inc., Milwaukee, Wis., a corporation of Deltaware Application February 15, 1956, Serial No. 565,648 14 Claims. (Cl. 74-536) This invention relates to improvements in detachable lever locking devices for electric switches, wherein the lever is to be retained in at least one position thereof until moved or released from such position by the operator; and particularly to locking devices including multiple sets of different cap parts which can be readily changed, and variously combined, for retaining the lever in a number of different combinations of desired positions, without requiring dismounting of the switch itself.

Electrical switches, such as those used on aircraft, are frequently of a multi-position type with a single operating lever to be manually moved to various positions relative to other switch parts and to the panel on which the switch is mounted. The lever positions should be readily changeable by the operator, but also the lever should be restrained against accidental undesired or inadvertent movement, due to shock or vibration or to action of the operator, from a locked position in which it has been placed by the operator. Under other conditions it is desired that the lever automatically return to a given position from one of the other positions and be locked in the return position. Where automatic lever movement is desired, it should be limited to only a preselected amount and with reference to a predetermined sequence of positions. In any of the above cases it is desired that the lock be positive and secure against shock and vibration and that the lever be incapable of accidental movement, or inadvertent or thoughtless operation, or an excessive amount of movement, such as overtravel.

It is therefore an object of the present invention to provide novel, improved, and less expensive locking means for a lever operable to a plurality of positions and which positively prevents accidental or inadvertent movement of the lever from a locked position to another position thereof.

Another object of the invention is to provide a locking device for the operating lever of a multi-position switch in which various locking parts are interchangeable and can be assembled for locking the lever in each of the switch positions or in only one or more of such positons.

Another object of the invention is to provide a locking device for multi-position switches, in which the number of parts and the weight of the device are reduced as compared with prior devices for the same purpose.

Another and more specific object of the invention is to increase the size of the operating lever of a multi-position switch of the character aforementioned, while retaining the possibility of mounting the switch in a standard size hole in a panel or other suitable support.

Another object of the invention is to minimize entry of moisture and dust into enclosed parts of such a switch, by providing for drainage of such foreign matter from around the outer end of the passage through the bushing for the lever of the switch, and by sealing the space between the lever and the peripheral wall of such passage.

Another object of the invention is to provide locking devices for the operating levers of multi-position electrical switches of the character aforementioned, which preserves 2,885,905 Faten'ted May 12, 1959 "ice visibility of the panel on which the switches are mounted and correspondingly conserves space on such panel.

Other objects and advantages of the invention will appear hereinafter, in connection with the accompanying drawings illustrating certain embodiments of the invention and which will now be described, it being understood that the embodiments shown are susceptible of various modifications without departing from the spirit and scope of the appended claims.

In the drawings, Figure l is a front elevation of a locking device for a switch operating lever which is adapted for manual oscillatory movement into and out of any one of three predetermined positions, in which it may be locked, for operating an electric switch, a fragmentary portion of which is illustrated; and the lever being shown locked in its intermediate position.

Fig. 2 is a longitudinal sectional view on the center line of a portion of the structure, looking in the same direction as in Fig. 1, on a somewhat larger scale, and with the lever in and locked in its right-hand extreme position.

Fig. 3 is a view partially in longitudinal central section, at right angles to the view of Fig. 2, and partially in elevation, with the lever in the intermediate position shown in Fig. 1.

Fig. 4 is a horizontal sectional view, taken on the line 44 of Fig. 1, looking in the direction of the arrows, and showing the means for locking the lever in any one of its three predetermined positions.

Fig. 5 is a side elevational view of the upper section of the cap shown in Fig. 4.

Fig. 6 is a horizontal sectional view, taken substantially on the plane of line 6-6 of Fig. 1, looking in the direction of the arrows.

Fig. 7 is a top plan view of coacting portions of one pair of cap members, which when assembled on a bushing and clipped together are adapted to provide for locking of the lever only in the intermediate one of its three operative positions.

Fig. 8 is a view similar to Fig. 7 providing for locking of the lever only in the upper end position thereof, and leaving the lever unlocked in its intermediate or mid-position and in the lower end position to which it may be moved.

Fig. 9 is a view similar to Fig. 7 providing for locking of the lever against movement fromits intermediate position toward its lower end position, but permitting relatively free manual movement of the lever from its intermediate position to its upper end position.

Fig. 10 is a view similar to Fig. 7, but providing for locking of the lever in each of its upper and lower end positions, and leaving the lever unlocked in the intermediate position thereof.

Fig. 11 is a view similar to Fig. 7, but showing means adapted for use with a two-position switch, in which the lever is adapted to be locked in either position.

Fig. 12 is a view, partially in elevation and partially in section on a longitudinal central plane, illustrating a modified form of the present invention in which the lever is automatically returned to an intermediate position from one end position, but locked against automatic return from its other end posit-ion.

Fig. 13 is a top plan View of the coacting cap portions of the locking. device of Fig. 12 which provides for locking of the lever in the lower end position and in the intermediate position of a multi-position device; to which intermediate position it is automatically returned from its upper end position upon manual release of the switch lever.

Fig. 14 is a view similar 'to Fig. 13, showing a threeposition type of switch, but providing for lockingof the ,lever only in its intermediate position; to which it is automatically returned from either of its end positions upon manual release of the switch lever; and

Fig. is a view similar to Fig. 13 but providing for locking of the lever only in one of its two operative posiing of the switch lever in any one of three positions. A n etal member 21 of inverted U- or saddle-shape is attached to the switch housing 16 in a well known manner and has its central portion formed with an apertured boss, as shown, against the lower surface of which the reduced end of the tubular bushing 22 is adapted to be upset, for attachment of said parts to each other.

Bushing 22 is shown in Fig. 2 as being substantially cylindrical, and is initially externally threaded to the upper end thereof for projection outwardly through a panel or other suitable support (not shown) for mounting therein. The bushing22 has a longitudinal external keyway 33 for receiving suitable means for predetermining the rotary position of the bushing relatively to the metal member 21 and for other purposes. An internal shoulder 24 is formed in bushing 22 toward the end thereof remote from the switch casing 16 and said bushing is externally peripherally grooved at 25 adjacent such end. An external flange 25 is thus formed adjacent the upper end of the bushing and such flange is also externally threaded. The bushing is of such length that washers, seal rings and two nuts can be placed thereon for mounting on the usual panel of up to one-eighth inch thickness. The switch casing 16, cover plate 17 and bushing 22 may be con sidered as coacting to form mounting means for the lever 18.

The lever 18 has an enlarged portion 27 which is within the bushing 22 when the parts are in their assembled relation, such portion being at the lever fulcrum point within the bushing. One surface 28 of the enlarged lever portion 27 is in the form of a segment of a sphere for movement 7 of the upper end of lever portion 27 in bearing engagement with the bushing shoulder 24 when the lever is oscillated in the passage through which it extends into the switch casing. A somewhat wedge-shaped groove is provided in the lever portion 27 to receive an annular member 29. The member 29 is preferably formed of a resilient rubber or rubber-like material not substantially affected by heat, vapors, etc., which may be present where the switch is to be used; and its inner diameter is of a size to grip the inner periphery of the groove in the lever while its outer diameter is of a size to seat at its outer edge against the inner peripheral surface of the bushing 22. The resilient member 29 is preferably under slight compression between the lever 18 and the bushing 22 and is of a thickness to permit lateral flexing in the lever groove without bodily shifting as the lever is oscillated. Therefore member 29 forms a seal effectively to prevent passage of moisture or other foreign matter through the bushing into the switch casing 16.

Generally similar parts 35 and 36 engage and extend about the flange 25 of the bushing and engage in the groove 25 formed therein, to form a cap for the end of the bushing; and such parts 35 and 36 provide an elongated opening therethrough, as shown in Fig. 4, whereby the lever 18 may be oscillated into either of two end positions and through an intermediate position, in respect of a switch of the three-position type. The cap members 35 and 36 are held in place by a one-piece resilient metal. clip 37 of a generally inverted cup shape but having a.

multiplicity of resilient fingers 38 respectively adapted to snap inwardly over a downwardly facing shoulder 39 on the cap members and bearing inwardly against the peripheral portions of the respective cap members beneath such shoulder. The cap parts 35, 36 are shown as formed to jointly provide three downwardly extending notches 40, 41, 42 (see Fig. 4) respectively adjacent the two ends of and centrally of the opening through the cap. Such sets of notches coact for jointly providing the two end positions and an intermediate position of the lever when the parts 35 and 36 are used. The several other cap portions are hereinafter described in further detail.

The lever 18 is formed with a pair of flanges 46, 46 between the enlarged portion 27 thereof and the outer end of the lever; said flanges cooperating with the straight walls of the elongated central opening in the cap to prevent rotation of the lever. A washer 47 is attached to the outer end of the lever 18 as by riveting over an integral extension 48 of lever 18. Washer 47 extends beyond the cross sectional area of the lever to serve as a downwardly facing flange at said end of the lever. A sleeve 50 is placed about the lever 18 and has external threads at the upper end thereof for cooperatively engaging the threads formed in a nut or knob 51 capping the sleeve and enclosing the end of the lever. Sleeve 50 is provided with a pair of diametrically opposed slots 50 and 50 extending downwardly from the upper end of said sleeve. As shown in Fig. 3 washer 47 is provided with a pair of lugs 47 and 47 which are adapted to fit into said slots 58 and 50 so that when washer 47 is rigidly attached to the upper end of lever 18 sleeve 50 will be positively held against rotation with respect to said lever. The nut 51 is preferably of substantially greater external diameter than the sleeve 50 to provide surfaces which may be gripped by the operators fingers for retraction of sleeve 50 from a locked position thereof.

The sleeve 50 is of larger internal diameter than the external diameter of the upper end portion of lever 18 and has an internal flange 52 at the lower end thereof to form a seat for one end of a helical compression spring 53, which bears at its other end against the lower surface of washer 47. Sleeve 50 also has a pair of integral downwardly extending substantially triangular projections 54 located at degrees spacing from each other and adapted for engagement in the cap notches (40, 41 and 42 of Fig. 4, for example) depending upon the position of the lever. The sleeve sub-assembly 5054 may be considered as a retractable lever member or portion which is external of the mounting means and coacts with the cap assembly for such purposes as will now be described.

Referring particularly to Figs. 3, 4 and 5, the cap parts 35 and 36 !are generally similar but the cap portion 35 has an inwardly projecting key portion 58 to enter the bushing keyway 33 for preventing rotation of the entire cap and one-piece clip assembly with respect to the bushing 22, whereas the cap portion 36 has no such key. For any given combination of lever positions in which it is desired to lock the lever 18, the cap halves 35, 36 coact to provide notches, as shown at 40, 41, 42 (or one-half of ta notch 41 when the division line between the cap parts falls within the notch). Each coacting pair of notch parts in the leap are in alinement so that the sleeve teeth 54 may simultaneously enter into a pair of the notches; the notches extending at a right angle to the direction of movement of the lever 18. Passages or slots 59 extend through each cap part from the inside to the outside surfaces thereof for drainage of moisture or foreign matter carried thereby, and which would otherwise accumulate in the cap and tend to drain into the inner portion of bushing 22, and thence into the switch casing 16.

There is no substantial wear upon the cap parts, and such parts can therefore be made as die castings of relatively soft metal. Unless the operator exerts a pull upon the sleeve unit 50-54 the spring 53 will remain in its expanded condition, with the respective teeth 54 biased into one of the sets of notches to a sufiicient extent to restrain the lever against movement out of a given position pending manual retraction and movement of the lever 18 to another position.

In operation, therefore, the operator must grip the sleeve- cap handle unit 50, 51 and exert a pull thereon longitudinally of the lever 18 to compress the spring 53 sufiiciently to raise the teeth 54 out of the then engaged set of notches. After the teethhave been disengaged from a notch, the lever 18 may be moved to any other position provided for by a locking cap unit, such as menn bers 35, 36 and clip 37 (in Fig. 1), according to the functions to be afforded by the particular switch.

The cap parts 35, 36 shown in Figs. 1 through 6 jointly providethree sets of notches whereby the lever may be locked in either of two endpositions or in an intermediate position. Such cap construction is accordingly particularly useful where a three-position switch is used and the switch is to be locked in each one of its three positions.

The combinations of pairs of cap parts shown in Figs. 7 to 11, inclusive, are likewise adapted to be assembled with respect to a bushing like the bushing 22 aforedescribed and with respect to the lever 18 as aforementioned, and to be held in assembled relationship by the one-piece resilient metal clip member 37 shown in Figs. 1 to 3, inclusive, and in Fig. 6.

The lower cap part 104 shown in Fig. 7 is identical with the corresponding cap part 104 in Fig. 9; whereas the upper cap part 105 in Fig. 7 is different from all the other cap parts herein illustrated. The cap parts of Fig. 7 are adapted formse with a switch actuating lever like that shown in Figs. 1 to 3; but in which said. lever may be locked only in its intermediate, or ofl, position, as indicated by the recesses 1114 and 1115 forming the intermediate cavity 106. It is to be understood that in each form of the invention herein disclosed the switch parts themselves (other than the locking means therefor) may be arranged to normally provide for. automatic spring return of the operating lever from one extreme position to the intermediate position (as shown in Fig. 12), or from either extreme position to said intermediate position; or *from one extreme position to the other in a two-- position type of switch; different forms of such momentary types of switch actuators being well known to those skilled in this art.

The upper cap part 187 in Fig. 8 is combined with a lower cap part 108, for use with a three-position switch having an intermediate ofi position, and an on position at each extreme or end position of the lever. lever (not shown) may be biased in any well known manner to return to its intermediate or oil? position at the midlength oi the slot 1118 when the lever is manually released from its extreme position 108 or when said lever is manually released after withdrawal of its locking lugs or cars from the end locking cavity designated by the numenal 107 The cap parts 104 and 109 in Fig. 9 are respectively recessed as indicated at 1114 1414* and at 109 1119 for cooperation with the lever lugs, to normally lock the lever against movement firom its intermediate position to its lower extreme position in the slot 109 1414 pending manual withdrawal of the lever lugs (54, 54, shown in Fig. 3) from engagement with the lower end walls 16 2 1M of the opposite portions of recess 1114*, 1134 On the contrary the switch lever 18 is relatively freely movable from its intermediate ofl position to its upper extreme position, with reference to Fig. 9, because of the relatively larger size orwidth of the recess portions 109 the bottoms of which extend entirely to the aforementioned recesses liM 1114 The cap parts 107 and 110 in Fig. 10 are recessed adjacent opposite end portions of the slot affording clearance for movement of the lswitch lever; such recesses being designated by the numerals 107 1117 and 111%,

'ihe

1 of the lever out of one extreme position and movement thereof to its other extreme position.

The cap parts 111 and 112 of Fig. 11 are respectively formed to provide a relatively short clearance slot 113 for the switch lever; it being understood that when the switch lever is adjacent the upper end wall of slot 113 it will be locked in position, preferably the off position of the switch mechanism, by engagement of the lever projections 54, 54 with the walls of the cavities formed at 111 111 and 112 112 formed at the meeting surfaces of the respective icap parts 111 and 112.

Oap part 112 in Fig. 11 and cap part 32 in Fig. 13 are respectively shown as being identical with the cap part 36 in Fig. 4, and are. shown as provided adjacent the lower end of the slots 113 (Fig. 11) and 113 (Fig. 13) for the switch lever with a pair of recesses 112 112, Fig. 11, and 87,87, Fig. 13, which are adapted to receive the projecting lugs on the switch lever to lock the same in its lower extreme position; which may, for example, with respect to Fig. 11, 'be presumed to be the single on position, of the switch.

The modified forms of my invention as illustrated in Figs. 12 through 15 in general include the locking device features previously described, together with means for automatically insuring return of the lever to an intermediate position upon manual release thereof from one extreme position (Figs. 12 and 13); or from either extreme position to an intermediate position (Fig. 14); or from one of its extreme positions to the other, in a twoposition switch (Fig. 15); the die-cast cap parts being formed so as to facilitate operation of the return means.

A metal support member 66 (Fig. 12) is formed to provide space between the cover member 17 for the insulating switch housing 16 and the metal support member 66 to which a plate 67 or the like is attached. Plate 67 serves as attaching means or as abutments for opposite ends 68 of a spring wire having two spaced helically wound, portions, one of which is shown at 68 said Wire having a normally straight portion 68 between the helical portions which continuously bears against the switch lever 69 to tend to return the level to its intermediate position, as illustrated.

The lever 69 is formed with a ball-like enlargement 70 and has a transverse aperture :for receiving a pivot pin 71. A bushing 74 is fixed in the opening in the metal support member 66 and is formed with a keyway 7'5 and an upper end flange 76 and is externally threaded for mounting upon a supporting panel, as aforedescn'bed. The interior of the bushing 74 is formed with its opposite end portions of substantially fiusto-conical contour, and with an intermediate cylindrical portion 77. A resilient, elastic, rubber or rubber-like sealing member 78 is formed as a short cylinder with an internal ball-shaped recess; the wall portions of which are adapted to grip the lever portion 70; and having integral external peripheral flanges at the ends to seat against the inner cylindrical surface 77 of the bushing for thereby sealing the lever in the bushing. The upper end portion of lever 69 carries the sleeve-nut unit 5ll54 previously described.

Bushing 74 is capped by two generally similar cap parts 81, 82 which are jointly of generally disk-like shape and coacting to define an elongated opening therethrough for accommodating the upper end portion of lever 69. Each cap part is formed with an internal flange to engage the bushing 74 under the upper end flange 76 thereof and the cap part 81 has a key 83 engageable in the keyway of the bushing to prevent rotation of the assembled cap parts relatively to the bushing '74. The cap parts are held in position by a punched and stamped resilient sheet metal clip 84 which is preferably the same as the clip 37 aforedescribed, and which coacts with the present cap parts in the same manner as previously described. The cap parts 81, 82 are likewise shaped to be engaged by and to hold sleeve teeth 54. As shown in Figs. 12 and 13, holding surfaces 87 are formed adjacent the right-hand end (Fig. 12) of the clearance Opening through the cap parts and another pair of holding surfaces 88 are formed intermediate the ends of said cap opening. The cap surfaces between the pair of holding surfaces 88 and the left-hand end of the cap opening are smooth curves and are designated 90 and 91 (see Fig. 13). Hence voluntary locking of the lever 69 is possible in the present construction either at the right-hand end position 87 (Fig. 13) or at the intermediate position designated 88 (when moving lever 69 from the end position 87).

If the handle unit 50, 51 of lever 69 is manually released after movement of said handle to its extreme lefthand position (Fig. 12) the spring 68 acts in an obvious manner to bias lever 69 toward the intermediate position thereof shown in Fig. 12. At the same time the coiled compression spring 53in handle 50, 51 (see Fig. 2) biases the teeth 54 of sleeve 50 against the downwardly curved cam surfaces 90 and 91 (Figs. 12 and 13) to assist in rapidly returning lever 69 to the intermediate position thereof shown in Fig. 12.

The cap of Fig. 14 comprises an upper part 81 (like the upper part 81 shown in Fig. 13) and a lower part 89, and has notches 93 only at the intermediate position while the cap surfaces are curved from the outer end positions toward the notches 93 so that the spring 53 within sleeve 50 (see Fig. 2) causes the teeth 54 to act against the pairs of cam surfaces 90, 91 or 97, 97 to automatically return or assist in returning the lever 69 to its intermediate (locked) position from either end position.

With cap parts like those shown in Fig. 14 it is to be understood that the single spring 68 of Fig. 12 might, under proper conditions, be omitted, or an additional spring, like 68, might be mounted on the left-hand side of lever 69. The circuits can therefore be closed in the end positions only so long as the lever 69 is held therein by the operator.

The cap parts 98 and 99 shown in Fig. provide holding surfaces or notches 100 at one end of the cap opening only and said cap parts have mated, continuously upwardly curved surfaces 101, 101 joining the locking end position 100 with the other end position 103 for the lever. Therefore the upper end of lever 69 may now be locked only by the cooperating pairs of surfaces designated by the numeral 100, and will be returned automatically to its extreme right-hand position (with reference to Fig. 12) by the action of spring-pressed teeth 54 (as shown in Fig. 12) against the spaced sets of cam surfaces 101, 101 shown in Fig. 15, unless the upper end of lever 69 is held in the aforementioned extreme left-hand end position by the operator. With a cap like that shown in Fig. 15 a spring like that shown in Fig. 12 may not be required; or, if employed, it should act to automatically throw the lower end portion of the lever 69 to its extreme left-hand position.

I claim:

1. In a detachable locking device of the character described, in combination, an externally threaded tubular metal bushing having an inner end portion of reduced diameter, said bushing having an external keyway formed therein and extending inwardly from the outer end thereof whereby the inner end portion thereof may be rigidly and non-rotatably attached to a switch housing, said bushing also having a peripheral groove formed therein spaced inwardly from the outer end thereof, a lever positioned within said bushing and adapted for pivotal movement relatively thereto, means for positively limiting said lever to pivotal movement in a single plane, said means comprising a cooperating pair of formed metal members, each of said members having an inwardly projecting por- .tion adapted to fit closely within the peripheral groove in said bushing, said formed metal members when jointly assembled on said bushing being adapted to completely surround the same, and a single punched and stamped resilient sheet metal member adapted to be pressed inwardly over said formed metal members jointly, said sheet metal member having a multiplicity of resilient lugs formed thereon for snap engagement with the inner surfaces of said formed metal members jointly, whereby the latter are positively retained in assembled relation to each other and to said bushing by said sheet metal member.

2. The combination according to claim 1, wherein one of said formed metal members is provided with an integral inwardly projecting lug adapted to fit closely within said keyway, whereby said formed metal members are jointly retained in a fixed position relatively to said bushing.

3. The combination according to claim 1, wherein said plurality of formed metal members are die castings of semi-circular contour and are retained in assembled relationship to each other only by said single punched and stamped resilient sheet metal member.

4. The combination according to claim 1, wherein said formed metal members are provided on opposite sides of the plane of pivotal movement of said lever with pairs of integral, transversely aligned, raised and indented portions of like contour, said lever having a retractable handle portion normally spring biased inwardly toward said formed metal members for cooperation therewith to positively retain said handle in at least one of a plurality of different angular positions, but subject to release from such position upon manual outward movement of said handle.

5. The combination according to claim 1, wherein said formed metal members are provided on opposite sides of the plane of pivotal movement of said lever with two matched groups of transversely aligned, alternate raised and indented portions, said lever having a retractable, plural-toothed handle portion normally springbiased inwardly toward said formed metal members for cooperation therewith to positively retain said handle in at least one position and to insure automatic return of said handle to said one position upon release thereof after manual movement thereof to at least one other alternative position.

6. The combination according to claim 1, wherein said formed metal members are provided on opposite sides of the plane of pivotal movement of said lever with transversely aligned, pairs of raised and indented portions of like contour, said transversely aligned pairs of raised portions being located in alternate relationship to said pairs of indented portions and being formed integrally with the latter, said lever having a retractable handle portion normally biased inwardly toward said formed metal members for cooperation therewith to normally insure automatic return of said handle to its intermediate position upon manual release thereof after manual movement of the same from engagement with said intermediate pair of indented portions.

7. The combination according to claim 1, wherein the cooperating pair of formed metal members are respectively provided with like inwardly extending arcuate surfaces so as to insure automatic return of said handle to one extreme position, upon manual release thereof after movement thereof to its other extreme position.

8. The combination according to claim 1, wherein various individual members of the respective pairs may be combined at will to afford various functionally different switching control characteristics.

9. In a detachable lever locking device for electric switches and the like, in combination, an externally threaded tubular metal bushing, a metal lever supported within said bushing for pivotal movement with respect thereto, a spring-biased retractable hollow handle member attached to said lever at the upper end of the latter, said handle member having a pair of oppositely disposed,

inwardly extending, substantially triangular projections at the lower end portion thereof, for the purpose set forth, means for positively insuring against rotary displacement of said lever relatively to said bushing, and means rigidly attached to said lever and having sliding engagement with said handle member for insuring against rotary displacement of said handle member relatively to said lever.

10. In a detachable lever locking device for electric switches, in combination, an externally threaded hollow metal bushing having a reduced inner end portion which is adapted for rigid, non-rotatable attachment to a cooperatively formed sheet metal casing member, the threaded portion of said bushing having a peripheral groove formed therein in a plane parallel to and offset inwardly from the outer end thereof, said bushing also having a single, straight line, lateral groove formed therein and extending throughout the threaded length thereof in a direction at a right angle to said peripheral groove, and a multiplicity of different lever locking members of outwardly convex, semi-circular peripheral contour adapted for use in pairs selectively, according to the particular controlling functions desired, the respective members of each pair being so formed as to provide for non-rotatable interlocking engagement thereof jointly with said peripheral and straight line lateral grooves upon complete assembly of all parts of the device, and a one-piece punched and stamped resilient sheet metal member having a multiplicity of integral inwardly projecting shouldered lugs formed thereon and insertable simultaneously over said lever locking members jointly with a snap fit to positively retain the latter in assembled position, a manually operable lever positioned within said bushing and supported for pivotal movement with respect thereto, an inwardly spring-biased retractable handle non-rotatably attached to the outer end portion of said lever, and said handle having a pair of transversely spaced, inwardly projecting teeth formed thereon for cooperation jointly with the pair of lever locking members to provide for automatic retention of said lever in at least one of a plurality of different positions thereof at will.

11. A device of the character set forth in claim 10, wherein said one-piece, punched and stamped sheet metal member is provided with a relatively large central opening to afford clearance for said lever, said retractable handle, and said transversely spaced pair of teeth formed on the latter.

12. A device of the character set forth in claim 11, wherein at least one pair of inwardly extending convex cam surfaces are provided upon one or both of said lever locking members, and wherein associated spring means are provided for insuring automatic return of the switch lever to a predetermined normal position thereof upon manual release of the switch handle.

13. A device of the character set forth in claim 12, wherein said means for insuring automatic return of the switch lever to a predetermined normal position thereof includes two laterally spaced parallel pairs of inwardly curved convex cam surfaces respectively formed on each of the particular pair of lever locking members aforementioned.

14. For an electric switch operating lever oscillatable in a mounting member, said lever having an inwardly spring-biased handle portion manually retractable outwardly with respect thereto, said handle portion having a pair of parallel inwardly extending teeth formed thereon at the inner end thereof, a lever lock through which said lever extends comprising a pair of sections of semi-circular contour jointly affording an upper surface of a shallow dome shape, said sections jointly providing an elongated opening therethrough which extends in a direction at right angles to the line of division therebetween, to thereby provide clearance for movement of said handle from at least one operating position thereof to another, at least one of said sections having a pair of recesses formed in the dome shaped upper surface thereof and opening to said elongated opening aforementioned, and said retractable handle portion when withdrawn from locking engagement with the walls of said pair of recesses being movable manually, or automatically under the influence of an associated biasing spring associated therewith, to another predetermined position thereof, for circuit control.

References Cited in the file of this patent UNITED STATES PATENTS 1,988,636 Thomas June 22, 1935 2,223,032 Farmer Nov. 26, 1940 2,246,919 Krantz June 24, 1941 2,409,022 Diedring Oct. 8, 1946 2,510,122 Lomholt June 6, 1950 2,723,571 Koenig Nov. 15, 1955 2,759,075 Hults Aug. 14, 1956

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