US2956135A - Hand operated switch - Google Patents

Description

E. L. FEIL HAND OPERATED SWITCH Oct, 11, 1960 Filed Jan. 18 1957' 5 Sheets-Sheet 1 INVENTOR.

Oct. 11,1960 E. L. FEILI 5 HAND OPERATED swn'cn Filed Jan. 18, 1957 *5 Sheets-Sheet a g I 7 l 0 s as Z .JJF

INVENTOR.'

Oct, 11, 1960 E. L. FElL 2,955,135

HAND OPERATED SWITCH Filed Jan. 18, 1 95? 5 Sheets-Sheet 5 IN V EN TOR. 44 m 1- United States Patent HAND OPERATED SWITCH Edward L. Feil, Euclid, Ohio, assignor to The Clark Controller Company, Cleveland, Ohio, a corporation of Ohio This invention relates generally to manually operable electric switches.

While the invention may be used generally as a circuit maker and breaker, it has particular application as a socalled manual starter for starting and stopping an electric motor.

A type of manual motor starter is known comprising switchcontacts in the circuit of the motor, which can be manually moved to closed position; and which have a snap mechanism that can be tripped manually to cause the contacts to go to open position with quick break or snap movement; and which mechanism will be tripped by an electric overload in the motor circuit.

The present invention relates to manual starters of this type.

The actual invention is that set forth in the appended claims.

The embodiment of the invention fully described hereinafter, comprises, in general the following.

The switch as a whole is detachably mounted upon the interior bottom wall of a sheet metal box-like casing, and a cover on the casing entirely encloses the switch except for an operating handle accessible through a handle open.- ing in the cover.

The switch has stationary and movable contacts, and a snap mechanism; and the snap mechanism is operable by the handle to disengage the contacts or engage them with snap action; and the mechanism is operated automatically by a thermal device to trip or disengage the contacts with snap action upon the occurrence of a current overload through the engaged contacts; and the mechanism is operable by the handle to reset the mechanism after automatically tripping.

The handle thus has four positions and these are indicated by legends on the handle visible through the handle opening in the casing.

The switch proper comprises a generally flat base mounted on the casing bottom wall as referred to; and the snap mechanism is permanently mounted as a unit on the base; and a housing, generally of bowl form downwardly open as viewed in the drawing, is attached to the .base covering the mechanism.

A pair of transversely spaced arms, connecting the handle to the mechanism, pass upwardly through spaced .apertures in the bowl bottom.

In its preferred form, as illustrated herein, there are three parallel current paths through the switch, each controlled by contacts, which adapt the switch as a starter for a three phase motor.

The parts constituting each of the said three paths comprise a pair of stationary contacts and the heating coil of a thermal tripping device; both in series befor all three paths, are in straight lines and the terminals are mounted on the outside of the housing bowl bottom ice 2 and exposed for ready access upon removing the casing cover.

There are movable bridging contacts, for bridging the pairs of stationary contacts, disposed outwardly of, or above, the housing bowl bottom, and a reciprocator connecting them with the mechanism, passes through another aperture in the bowl bottom.

Thermal devices are mounted on the underside of the bowl bottom, one for each heating coil.

Upon removing the casing cover, the base with all of the above described parts thereon can readily be detached from the casing bottom wall and removed as a unit, for inspection.

The handle is readily detachable; and upon removing the handle and the bridging contacts, the bowl housing, by virtue of said apertures, may be removed from the base, leaving the mechanism mounted on the base and exposed for inspection.

Production assembly in the first instance is facilitated by reversal of these removing operations.

In the aforesaid arrangement, the mechanism and thermal devices are disposed under the said three conducting paths and thereby do not add to the length between the terminals of the paths, and by the economy of space thus effected, there is made room for thermal devices for all three of the current paths which is not possible in prior switches of this class without unduly increasing the length of the switch as a whole. The handle by being detachable also makes possible a switch of overall minimum length.

A connection is provided by which the one mechanism can be tripped, on current overload, by any one of the three thermal devices alone, or by any two, or all three of them concurrently.

The bowl housing is molded from insulating material and has arc chamber walls surrounding the contacts on three sides at their make and break zones; and the reciprocator carrying the bridging contacts is molded from insulating material and comprises a transverse bar portion carrying all three of the bridging contacts and formed to provide a fourth chamber wall; whereby the contact make and break zones are each surrounded by arc chamber walls on all four sides.

The said transverse reciprocator is provided with finlike barriers, between the pairs of bridging contacts which prevents flash-over from any current path to another.

The detachable connection for the handle comprises a pin going through the handle and through apertures in the said handle arms on each side of it, which open into slots. The handle is normally prevented from rotating on the pin by projections on the handle overlapping portions of the arms. The pin is shiftable manually axially against the force of a spring and thereupon disposes small diameter portions of the pin opposite to the slots, whereby the pin can be withdrawn from the apertures through the slots and the handle freed therefrom, and the projections freed from the arms, to permit the handle to be removed.

The pin has a finger mounted on an end thereof at a side of the handle, which is movable laterally of the bandle with axial movement of the pin, and then rotatable with the pin.

Normally, an end of the finger is disposed in a recess in the side of the handle and is then in .an out of use position.

When the pin is moved axially as described, the finger end is withdrawn thereby from the recess and the finger is then manually rotatable downwardly to a position in which its end is disposed behind a shoulder on the housing bowl.

This can only be done when the handle is in the oil 3 position and it locks the handle against accidental or unintended movement to the on" position.

The aforesaid snap action mechanism is in general of the over-center spring type; and the parts are economically made as flat sheet metal stampings, mounted on pins that are supported in the side walls or legs of a U-shape metal frame mounted, preferably permanently, on the said base.

Movement over and beyond dead center condition occurs when the handle and handle arms are moved from off to on position or vice versa; and provision is made by which, if the parts should tend to stick or for other reason fail to go over center, movement of the handle arms will cause the arms to engage the parts and force them to go over and beyond'dead center.

The said three thermal devices are alike and each of a known soldered shaft type, and comprising a finger that is snapped upwardly by a'spring when the solder is melted by heat in the heating coil; and is reset by forcing the finger downward.

Provision is made by which the handle arms when moved, to reset position, after tripping, as mentioned, will forcibly reset the fingers of any one or more of the devices that have snapped upwardly.

The snap mechanism comprises a latch that moves upon occurrence of an overload and a toggle connected to the over-center spring action. One end of the toggle is connected to a fulcrum carried by the latch. When the latch is moved because of an overload, the latch carried fulcrum is shifted to cause the snap mechanism to operate and open the contacts.

The embodiment illustrated and described herein is particularly adapted as a starter for a three phase motor, by having three current paths therethrough to be made and broken; but it is to be understood that the embodiment may comprise parts to make and break only one or two current paths therethrough and used for other purposes; and that while thermal overload devices are provided in all three of current paths illustrated and described, the overload device in one of the paths, say the middle path, may if desired, be omitted.

The objects of the invention are to provide a switch having the features briefly described above, singly or in combination.

An embodiment of the invention is fully disclosed in the following description taken in connection with the accompanying drawing, in which:

Figs. 1 and 2, are respectively side elevational and top plan views showing a sheet metal casing in which the switch part of the invention is enclosed; Fig. 2 showing an opening in the top through which a switch operating handle projects;

Fig. 3 is a sectional view from the plane 3-3 of Fig. 1, to enlarged scale, full size, showing the switch in top plan;

Fig. 4 is a longitudinal sectional view of the embodiment of Fig. 3 also full scale, from the plane 44 ,of Fig. 3; with a switch handle shown in side elevation, and a mounting pin of the handle broken off and in cross section;

Fig. 5 is a fragmentary sectional view from the plane 5-5 of Fig. 4; and with bridging contacts of Fig. 4 removed;

Fig. 6 is a fragmentary plan view in the direction of the arrow 6 of Fig. 4, with stationary and bridging contacts of Fig. 4 removed;

Fig. 7 is a fragmentary view of a part of the switch of Fig. 3, but with the handle of Fig. 3 omitted;

Figs. 8, 9, 10 and 11 are views similar to part of Fig. 4, in some respects diagrammatic, showing a switch and operating snap mechanism therefor in different operated positions; and these views may be referred generally to the plane 8 of Fig. 12;

Fig. 12 is a fragmentary plan view of the mechanism of Fig. 8 from the plane 12 of Fig. 8;

Figs. 13, 14, 15 and 16 are top plan views of a handle as seen through an opening in the casing of Fig. 2, in the different operated positions, respectively, of Figs. 8, 9,10 and 11;

Fig. 17 is a diagrammatic view, illustrating different angular positions of the handle corresponding to Figs. 8, 9, 10 and 11;

Fig. 18 is a fragmentary view similar to a part of Fig. 4 illustrating in more detail, a thermal trip device of Fig. 4;

Fig. 19 is a sectional view from the plane 19 of Fig. 18; I

Fig. 20 is a fragmentary view from the plane 2020: of Fig. 18;

Fig. 21 is a side elevational view of a handle and part of a housing; from the plane 2121 of Fig. 3;

Fig. 22 is a view in the direction of the arrow 22 of Fig. 21, with part broken away and in section;

Fig. 23 is a View similar to Fig. 22 with operable parts for detaching the handle shown in operated positions;

Fig. 24 is a side elevational view from the plane 2424. of Fig. 23;

Fig. 25 is a view similar to Fig. 21 but with operable.-

parts thereof locking the handle in operated positiom Referring to the drawing, the switch is shown in hori-- zontal position for convenience of description, but usually will be used in vertical position.

The switch proper as shown in Figs. 3 and 4 com-- prises a metal platelike base 33 and an inverted :bowl shaped housing 34 downwardly open, formed from in-- sulating material mounted on the base 33 by screws 35..

The switch proper is enclosed within a casing, shownin Figs. 1 and 2 to small scale, comprising an upwardly open box 1 and a downwardly open overlapping box. cover *2 mounted detachably thereon by slot and screw connections one of which is shown at 3, Fig. l.

The box cover 2 has a rectangular opening 4 there-- through giving access and freedom of movement to a: grip 5 on an operating handle 6, by which, as will be: shown later, the handle .can be oscillated back and forth. arcuately around the .aXis of a pin A, Fig. 4, to different. switch operating positions.

The handle 6 has an arcuate coaxial upper surface 7 Fig. 4, and the opening 4 is in a corresponding arcuately formed portion 8 of the casing cover, close to which the surface 7 of the handle is overlappingly disposed, so that the handle in all positions thereof substantially closes the opening 4. As will be described the handle 6 is movable, manually, to an on position to close switch contacts; and to an off position to open the contacts; and moves automatically to a tripped position to open the contacts upon the occurrence of current overload through the confacts; and is movable manually to a reset position after automatic tripping, to restore the contacts to manual operation.

Legends ON, OFF, TRIPPED and RESET are provided on the surface 7 of the handle, and come into position to be visible to the operator to indicate the said respective positions of the switch, as shown in Figs. 13, l4, l5 and 16.

The handle 6 is attached to a pair of spaced handle arms 910, see Figs. 4, 8 to 10 and 12, oscillatable on a stationary pin A of a snap mechanism to be described; and the arms go upwardly to the handle from the mechanism through slots 211-212 in the bowl housing, see Fig. 7; and the handle is detachable from the arms by the following construction with reference to Figs. 4 and 21 to 25.

The ends of the arms 910 are generally of hook form, being provided with aligned circular perforations 11-12 opening into slots 1314 of smaller width than the perforations.

Outwardly of the slots 1314, the arms have fingers 15-. 6.

Under the fingers 15-16 are lower stops 17-18 on the handle.

Above the fingers 15-16, but displaced therefrom to ward the left, as viewed in the drawing, are upper stops 19-20 having grooves 22 receiving the upper sides of the fingers 15-16.

The underside of the handle 6 is hollowed out to provide opposite spaced ribs 23-24.

A handle pin 25 has large diameter portions 26-27 normally in corresponding bores in the ribs, and rotatable and axially slidable therein; and normally retained in the bores in the retracted axial position of Fig. 22, by a spring 28 reacting between the rib 24 and a collar 29 on the pin or a split ring attached thereto, and abutting upon the rib 23.

In this axial position of the pin 25, its large diameter portions 26-27 are in the perforations 11-12 of the handle arms, and as indicated in Fig. 4, this keeps the handle 6 and its pin 25 from shifting toward the right, as viewed; and keeps the lower stops 17-18 under the fingers 15-16 and the stops 19-20 above the fingers, so that the handle 6 cannot rock on the pin 25; and the handle is thus attached to the handle arms 9-10.

To detach the handle, the pin 25 is shifted axially, against the spring tension to the position of Fig. 23, by pressing manually on a knob 29a on the pin. The pin has small diameter portions 30-31, which upon thus axially shifting the pin, are moved to positions opposite the slots 13-14 as shown in Fig. 23.

The handle and pin may now be moved toward the right, as viewed, the small diameter portions of the pin moving in the slots 13-14, and the parts going to the position indicated in Fig. 24, where the small diameter portion 31 of the pin is entirely out of the slot 14.

In this position of the handle 6 the lower stops 17-18 are removed from under the fingers 15-16, as shown for the Stop 18 of Fig. 24, and as will be apparent from Fig. 24, the handle may be moved upwardly and detached from the handle arms 9-10.

Obviously it may be reattached by a reversal of the foregoing operations.

At this point it may be interjected that the handle arms 9-10 may be locked against their oscillating movements around the fixed pin A, as aforesaid, and this is provided for when the arms are in the off positions of Figs. 3, 4 and 8 to be described, to prevent accidental or unintended operation of the switch to the on position. This is done as follows with reference to Figs. 4, 7, 21 to 23 and 25.

In Fig. 7, the handle arms 9-10 are shown as coming up through the bowl housing 34 through slots 211-212 therein and forwardly thereof is a shoulder 32 on the bowl housing.

The passage of the arms through the housing is indicated in Fig. 4.

In Fig. 4 also is shown the shoulder 32; and in Figs. 21 and 25 the shoulder is reproduced on a fragmentary portion of the housing 34. The handle arms are locked as mentioned by'an obstruction on the handle moved optionally to a position to abut upon this shoulder 32 as follows.

As shown in Figs. 21, 2-2 and 23, a locking bar 36 is secured upon the end of the handle pin 25 opposite the manual knob 29a, and is therefore movable axially and rotatively with the pin.

The locking bar 36 has a body flange 37, on the end of which is a finger 38, which in the normal position of the parts, Figs. 21 and 22, holds the bar in an out of use position by being projected into a recess 39 in the side of the handle 6.

When the pin 25 is moved axially, manually, as described, the -locking bar 36 moves with it to the position of Fig. 23, which withdraws the finger 38 from the recess 39 and then the bar 36 can be hinged downwardly, as viewed, the pin being free to rotate to accommodate this movement.

The flange 37 overlaps the shoulder 32 and stops the downward hinging movement as in Fig. 25.

The locking bar 36 also has a flange 40 depending therefrom, the end of which lodges behind the shoulder 32, as in Fig. 25, and this locks the handle 6 and arms 9-10 against being oscillated toward the right away from the said off position.

Reversal of the foregoing operations will restore the finger 38 into the recess 39, releasing the lock, as is obvious.

Mounted on top of the inverted bowl housing 34 are the parts of three parallel conducting paths, which adapt the switch for use as a three phase motor starter.

The parts constituting these several paths are alike, and a description of one of them say the middle one will sufiice as shown in Fig. 4 and indicated in Fig. 3.

It comprises a terminal 41 at the left end as viewed, mounted on the housing by a screw 42 and having a terminal screw 43 thereon for Wire connection to say a motor;

A stationary contact element 44 having a contact tip 45 thereon, and mounted on the housing by a screw 46;

A thermal device heating coil 47 connected at opposite free ends by screws 48-49 to the terminal element 41 and the contact element 44;

Another stationary contact element 50 having a contact tip 45A, mounted on the housing by a screw 51, and continuing as a terminal element having a terminal screw 51A thereon for wire connection to, say, supply lines.

The inverted bowl housing has a bowl bottom wall portion 52, and a thermal device, generally at 53 depends therefrom being mounted thereon by bolts 54, and, err-- tending upwardly through the wall 52 and coaxial within the coil 47 has a thermo-responsive shaft construction 55..

This thermal device is shown in Fig. 18 in more detail. than in Fig. 4, and is shown separately in Fig. 20.

It is generally of known construction as follows.

A stationary tube 56 of the device, has a shaft 57 therein connected at its lower end to a toothed wheel 58, and the shaft is soldered to the tube.

Stationary arms 59-60 extend downwardly from the supporting wall 52 and have a pin 61 in their lower ends on which is oscillable a trip finger 62 by upstanding cars 63 thereof hinged on the pin 61.

An upwardly extending leaf spring 64 is secured to one of the cars 63 and at its upper end has a tooth 65 engaged by its resilience with the teeth of the wheel 58.

A spring 66 around the pin 61 reacts on the trip finger 62 and on the arm 60 tending to snap the finger upwardly and rotate the wheel 58 but restrained from doing so by the solder.

Upon heating the shaft constructiton 55 by an overload value of current in the coil 47, the solder melts and the Wheel 58 is released and the trip finger 62 is snapped upwardly by the spring 66 from the normal horizontal position shown in Figs. 18 and 4, to the dotted line position 62A in Fig. 18, and solid line position Fig. 10.

The upper side of the bowl housing is formed to have a chamber 67 see Figs. 4, 5 and 6, by chamber walls on three sides at 69-70-71; and a chamber 68 having like Walls 72, 73 and 74; into which the contact elements 44 and 50 respectively extend, and in which the contact tips 45 and 45A are disposed.

These chambers are, as will be apparent, in line with the middle conducting path over the top of the bowl housing here being described; and it may be interjected here that in line with the other two conducting paths, there are pairs of chambers 75-76 and 77-78 for the contacts thereof, like the chambers 67-68.

A reciprocator comprising a transverse bar 79 rectangular in cross section and formed from insulating material Figs. 5 and 6, extends transversely across the bowl housing, between the inner ends of the chamber walls 72-74 and 69-71 and constitutes a fourth chamber wall for each of the chambers 6768; and provides alike fourth wall for the chambers 7576 and 77-78.

A metal, movable bridging contact bar 80 rests upon the top of the transverse bar 79 and has contact tips 81-81A on its underside aligned with the stationary contact tips 45-45A.

The bridging bar 80 is mounted on a post 82 of oblong rectangular cross section embedded in the bar 79 and extending through a washer 83 and having a head 84 overlapping a washer 83 on the post, and a spring 85 around the post reacts between the 'bar 80 and the washer 83.

The assembly of these parts is of known construction. It comprises a first oblong short rectangular perforation in the washer aligned with the head 84, but shorter than the head so that the ends of the head overlap its ends.

To detach the washer 83 it is moved downwardly on the post until it comes to a neck thereon around which it is rotated ninety degrees; and the Washer has a long perforation at right angles to the short perforation which is then directly under the head; and the washer is then moved upwardly telescoping the long perforation over the head to remove the washer. The long perforation is shown at 86 in Fig. 3.

The washer may be reattached by reversal of the foregoing operation.

The bridging bar 80 is held down on the transverse bar with spring pressure as is apparent.

The washer 83 is thus readily removed and the spring 85 and bridging contact 80 may then be readily removed.

In operation later to be described the bridging bar 80 is moved downwardly to engage its tips 8181A with the stationary contact tips 4545A and then moves farther holding the contacts in closed condition under yieldable spring pressure.

The transverse bar 79 carries three posts and bridging bars like the post 82 and bridging bar 80 above described, for the said respective three conducting paths, and for simplification of the drawing, the posts have been shown in Fig. 6 at 88, 82 and 89 with the bridging bars removed and in Fig. the posts 88, 82 and 89 and the three bridging bars 90, 80 and 91 have been shown with the washers and springs removed.

The transverse bar 79 is preferably molded from insulating material; and barriers 139 and 140 are formed on it, between each adjacent two of the sets of contacts, extending both upwardly and downwardly and preclude the possibility of flash over from one set of contacts to the other.

Under the bowl housing 34 is a snap mechanism to be described, operated by oscillation of the handle arms 910 by the handle, which snaps the transverse bar 79 down and up to engage and disengage the said movable and stationary contacts. The handle arms are described above as oscillatable on a stationary pin A of the mechanism.

The transverse bar 79 has lugs 9293, depending therefrom through an aperture 94 in the housing, Fig. 4, and a pin B of the mechanism is projected through aligned holes in the lugs, Figs. 4 and 5.

As described, the handle 6 and the bridging bars 90-8091 are readily detachable. It is an important part of the invention that after detaching them and after detaching the housing from the base 33 at the screws 35, the entire bowl housing 34 and all of the parts mounted thereon as described can be removed as a unit, without disturbing the snap mechanism, leaving the arms 9--10 and the lugs 92-93 on the mechanism pins A and B and exposing the mechanism for inspection; and independent operation; this removal of the unit being made possible by the arm slots 211-212 described for Fig. 7 and the lug aperture 94 described for Fig. 4.

To give access to the screws 35-35 for this purpose the base 33 as shown in Figs. 3 and 4 is mounted on the bottom casing wall 95 by screws 96-96 and 97 in 8 slots 98--98-99 formed so that upon loosening the screws 9696 and 97 the base 33 can he slid toward the right as viewed and its right end raised to clear the screw 97 and then slid further to the right to clear the screws 9696; whereby the base 33 can be removed from the casing, and the screws 3535 exposed for access thereto.

The said snap mechanism will now be described, and is shown in the said off condition in Figs. 4 and 8; in the on condition in Fig. 9; in the overload tripped condition in Fig. 10; and in the reset condition in Fig. 11, see also Fig. 12.

A metal mechanism frame 100 of U-form comprising a closed end 101 and spaced side legs 102103, see Figs. 4 and 19, has the closed end 101 mounted, preferably permanently, on the base 33 by screws 104-104, Fig. 4 with the side legs 102103 extending, parallel, upwardly therefrom.

The said horizontal pin A is mounted in aligned holes in the frame legs 102--103.

The handle arms 910 are alike flat sheet metal stampings, mounted to oscillate on the pin A and are formed to comprise upwardly extending handle portions 105, generally horizontal portions 106, large eyes 107, and extensions 108; the latter connected to and carrying a horizontal pin C projected therethrough.

A pair of alike flat links 109 of the bell crank type stamped from sheet metal have mid-points mounted on the said pin B and one leg 110 mounted on the pin A, the other leg 111 at an acute angle to the leg 110, carrying a horizontal pin D which, extends through aligned arcuate slots 112 in the side legs 102-103 of the frame 100 concentric with the pin A, and upon one end of which, in operation, the pin D is stopped as in Figs. 4, 8, 10 and 11 and on the other end of which it is stopped as in Fig. 9.

A latch 113, stamped from fiat sheet metal has an intermediate portion mounted on a stationary horizontal pin E which at its ends is supported in holes in the side legs 102-103. To the left of the pin E, as viewed, it has an upwardly inclined portion 114 and in its left end is a notch 115; and to the right of the pin E it has an upwardly inclined portion 116 carrying a short pin F, and beyond the pin F has a hook portion 117 and a prong 118 of which, as in Figs. 10, the hook portion may hook over the pin C, or as in Figs. 8-11 and 4 the prong 118 may engage the top of the pin C.

A pair of stamped flat sheet metal links 119119 are mounted at one end on the pin F and at the other end carry a pin G, which goes through the eye 107.

A pair of stamped flat sheet metal links 120-120 are mounted at one end on the pin G and at the other end on the pin D.

A pair of parallel triggers 121121 are mounted at their right ends on the pin A and are connected together by a generally horizontal web 122, and extend toward the left therefrom, all made from a metal stamping in one piece and bent; the web being under the pin A, Figs. 8 to 1'2 and 19.

The right hand edge of the web 122 is disposed so that in operation it may at times be engaged by the notch 115 of the latch 113.

A pair of tension springs 12-3123 are connected to and between the pins G and C; and a tension spring 124 is connected to the pin D and hooked over the left end of the trigger web 122 and being below the pin A gives counterclockwise torque to the triggers 121121.

The said frame side legs t102-103 have vertical aligned slots 137138 therein.

The aforesaid thermal device 53 is described above for the middle one of the said three conducting paths of the switch, and its said trip finger 62 thereof extends between the frame side legs 102-103, Figs. 18 and 19. The other two devices for the other two conducting paths, are mounted in the same way as that described for the device 53 and as indicated in Fig. 19 they have trip fingers 125-126 parallel to and at the same level as to the trip finger 62, beyond opposite sides of the U-frame 100.

A flat transverse trip bar 127 stamped from sheet insulating material, extends through the aligned slots 137- 138 in the frame legs 102-103 and is slidable up and down therein and guided thereby; and has horizontally aligned notch edges 128-129-130 normally resting upon all of the trip fingers 125, 62 and 12.6 to support the trip bar 127 in the slots, see Figs. 19' and 18.

The trip bar 127 has feet 131-132 disposed a short distance above the base 39, Fig. 19, and has a top edge 133 parallel to the trip fingers 125-62-126.

Operation of the snap mechanism will now be described.

It will be assumed that the mechanism is in the aforesaid condition of Figs. 4 and 8.

The springs 123-123 between the pins G and C, being above the pin F on the latch 113, are pulling on the pin G, tending to rock the links 119 clockwise around the pin F. p

The pin G therefore pulls on the links 120 and pin D, and thereby pin D is held against the right end of the slot 112 as a stop therefor.

The pin D is in the bell crank 109 and holds the bell crank in a stopped counterclockwise position around the stationary pin A and thereby holds the pin B, and the transverse bar 79 and bridging contact bars 90-80-91 of all three conducting paths in elevated position with the switch contacts open.

The pin G also presses the links 119 upon the pin F by the spring force, but the pin F, on the latch 113 cannot move, because the latch cannot rotate on the stationary pin E, its left end being locked by notch 115 engaged with trigger web 122 and the latter being held counterclockwise by the spring 124.

The links 120 and 119 and pin G thus constitute a bent toggle between the pin D and the pin F on the latch, the pin F acting as a toggle fulcrum.

The handle arms 9-10 and handle 6 are thus held in a definite predetermined off position, which can therefore be correctly indicated on the handle legends as described. The right end of the arms 9-10 cannot move up because the pin C is stopped by the underside of the lever prong 118; and while the pin C is free to be moved downward, does not do so because that would lengthen the springs 123-123, and they resist it.

To operate the switch to the on position, the pin C is moved downward by the operator, by moving the handle arms 9-10 clockwise around the stationary pin A in Figs. 4 and 8 and the parts snap to the on condition of Fig. 9 as follows.

The latch 113 remains unmoved as before.

The center line of the pins C-G is moved below the pin F on the latch; and the toggle comprising the links 119-120 straightens out, reacting at the right end on the pin F as a fulcrum and at the left end moving the pin D to the left end of the slot 112 whereon it is stopped.

The pin D in so moving rocks the bell crank 109 clockwise on the stationary pin A, moving the pin B downwardly, which as will now be understood, closes the switch contacts.

This occurs with snap action caused by the springs as soon as their line of action, between pins G and C goes to overcenter condition passing the pin F.

The extensions 108 of the arms 9-10 go down into contact with the base 33 as shown in Fig. 9 and are stopped thereon in a definite position whereby the legend on the handle 6 can indicate on position correctly as shown in Fig. 14.

The arms 9-10 remain in the on position of Fig. 9 when the operator releases the handle. When the pin C starts to move downward as referred to, the springs 123-123 are lengthened and after they snap the toggle 119-120 as referred to they shorten again, and thus resist upward movement of the pin C.

When the pin C is moved downward, to cause the line of action between pins C and G to pass the pin F, the pin G, due to wear of the parts or to friction, may tend to stick or lag and not snap down to the position of Fig. 9, and to insure that it will snap down, the eyes 107 in the handle arms 9-10 have each an edge 134 so disposed as to come into contact with the pin G and forcibly move it toward or beyond the dead center position.

With the switch and mechanism in the on condition of Fig. 9, and with the switch contacts closed, as will be understood, if an overload current occurs, say in the middle conducting path of the switch here to be considered, the thermal device 53, has its trip finger 62 at that moment in the position of Figs. 9, l8 and 19 and the top edge 133 of the trip bar 127, resting on the finger, is slightly below the triggers 121-121.

When the overload current actuates the thermal device 53, the trip finger 62 snaps upwardly as described, to the dotted line position 62A of Fig. 18 and solid line position Fig. 10; and the mechanism snaps to the tripped condition of Fig. 10 as follows.

As shown in Fig. 10 the trip finger 62 has elevated the trip bar 127 and its upper edge 133 has rocked the triggers 121 around the stationary pin A against the tension of the spring 124 and has withdrawn the trigger web 122 from the notch of the latch 113, and freed the latch, from its locked position of Fig. 9.

Before this, when the parts were in the on condition of Fig. 9, the springs 123 pulling on the pin G were exerting pressure on the pin F applying torque to the latch tending to rotate it clockwise around the stationary pin E.

Now that the latch has been freed, it is so rotated with snap action and goes to the position of Fig. 10, where it is stopped by the hook portion 117 thereof engaging the pin C. i

The pin F carried by the latch thus moves to a position below the line of spring action between the pins G and C as in Fig. 10.

Then force of the springs 123-123 accordingly moves the pin G toward the right as viewed, to the position of Fig. 10 and the pin G, pulling on the links pulls the pin D to the right end of the slot 112 upon which it is stopped.

This movement of the pin D rocks the bell crank 109 counterclockwise around the stationary pin A and elevates the pin B, opening the switch contacts as will now be understood.

As mentioned, the pin F on the latch is a fulcrum for one end of a toggle comprising the links 120, 119 and the pin G; and the snap movement of the parts from the on position of Fig. 9 to the tripped position of Fig. 10 thus results from shifting the position of a toggle fulcrum on a latch, which is believed to be a novel principle in the art.

In going to tripped conditions of Fig. 10, the handle arms 9-10 as will be seen, move counterclockwise to a position between their positions in on and off condition, and because of being stopped by the pin D at the end of the slot 112, will remain in that position, and the position will be definite so that the legends on the handle will correctly indicate that thermal trip has occurred, as shown in Fig. 15.

The foregoing describes thermal trip for the trip finger 62 for overload in the middle conducting path of the switch.

Overload current in the two other paths will similarly snap upwardly the trip fingers 125-126 of their thermal devices.

As will be seen from Fig. 19 when the trip finger 62 snaps upwardly, the trip bar 127 will be bodily elevated and elevate its top actuating edge 133 for the described purposes. If either of the trip fingers 125 and 126 snaps upwardly, but the others do not, the trip bar 127 will be elevated at one end and elevate the corresponding end of the actuating edge 133, rocking the bar upon the trip fingers that remain unsnapped, and thus tilting the bar. I

The triggers 121-121 above the edge 133 are spaced apart sufliciently and close enough to the edge 133 so that in the said tilted position of the bar it will engage and elevate one or the other of the trip fingers to trip the mechanism as described.

Thus an overload in any one, or any two, or all three of the current paths will trip the mechanism and open the switch contacts as described.

To restore the mechanism to normal operating condition after thermal tripping it is reset by the operator from the tripped condition of Fig. .to the reset condition of Fig. 11 and then released by the operator whereupon it goes to the off condition of Fig. 8.

To do this the handle arms 9-10 are moved counterclockwise as viewed in Fig. 10, beyond the described off position thereof.

The arms 9-10 have lower edges, which before tripping are spaced above the top edge 133 of the tripping bar 127, as shown in Fig. 4; and which are engaged by the upper edge 133 of the tripping bar 127 when it moves upwardly upon tripping, see Fig. 10.

The said counterclockwise movement of the handle arms 9-10 around the stationary pin A, to reset the mechanism move these edges downwardly, thereby moving the tripping bar 127 downwardly to the position of Fig. 11 and causing the tripping bar to restore downwardly to normal, positions the trip fingers of the thermal devices that caused tripping, as shown in Fig. 11.

The triggers 121 engaged with the top edge 133 of the trip bar 127, tend to remain in contact with the edge 133 and tend to follow the edge downwardly due to the spring 124 but do not do so for the following reasons.

The counterclockwise resetting movement of the handle arms 9-10 raises the pin C from the position of Fig. 10 to that of Fig. 11 and rocks the latch 113 counterclockwise around the stationary pin E by the engagement of the pin C with the hook portion 17 and prong 118 of the latch.

The latch on its left end, below the notch 115, has a rounded camming edge 136 which upon rocking of the latch as just described comes into contact with the web 122 of the triggers 121, and'in going from the position of Fig. 10 to that of Fig. 11, it cammingly rotates the web 122 and triggers 121 clockwise around the pin A to res-tore the triggers to normal positions above the top edge 133 of the tripping bar 127, as shown in Fig. 11.

Counterclockwise rotation of the latch 113 as just described is stopped by engagement with the pin D as shown in Fig. 11 with the notch 115 a little below the web 122; and stopping the latch also stops the resetting movement of the handle arms 9-10 as will be apparent, so that there is no liability that the trip bar 127 will be pushed down too far by the edges 135 or beyond a desired normal position.

The handle arms 9-10 being thus stopped in a definite position, the legends on the handle indicate reset correctly, as shown in Fig. 16.

When the operator releases the handle arms after resetting, the reaction of the springs 123-123 causes the handle arms 9-10 to settle back clockwise and the latch is thereby caused to settle back clockwise until the notch 115 is in locked engagement with the trigger web 122,

and the mechanism is then again in the normal off con-' dition of Fig. 8, as indicated in Fig. 13.

It is to be noted that the edges of the circular slots 112 through which the pin D extends, are not guides for the pin. The pin D is constrained to oscillate in a circular are around the stationary pin A independently of the slot edges by virtue of the one piece bell crank 109 formed of the legs 110-111. Wear on the pin D and slot edges is thus avoided.

The aperture 112 is preferably provided'of circular slot form as 'a convenient means of providing the rounded 12 pin embracing stops at the ends of the slot for the pin D.

In some cases, it will be suflicient to omit the thermal overload tripping device 53 from one of the conducting lines through the switch; and when this is done, the heating coil 47 can also be omitted and a wire substituted therefor between the screws 48 and 49, Fig. 4.

A part of the invention resides in the snap mechanism and its mode of operation. Therefore some of the advantages of the invention may be had, with only two or even one of the three conducting paths through the device, as described.

Normally, the switch is operated manually between the off and on positions. Once in the on position, the switch is manually operated to the off position by the operator moving handle 6 counterclockwise, Fig. 9 to Fig. 8. This moves handle arms 9 and 10 counterclockwise around the stationary pin A and the parts snap to the off position of Fig. 8 as follows.

The latch 113 remains unmoved as before.

The centerline of pins C and G is moved above pin F on latch 113. The toggle comprising links 119 and 120 collapses or breaks due to the tension in springs 123-123 and using pin F as a fulcrum at its right end. By collapsing, the left end of the toggle moves pin D to the right end of slot 112 Whereon it is stopped.

Pin D by this movement rocks bell crank 109 counterclockwise on stationary pin A to move pin B upwardly, which as hereinbefore described opens the switch contacts.

This occurs with snap action as soon as the line of action of'pins C and G goes beyond overcenter" condition, passing pin F, because of springs 123-123.

Pin C moves counterclockwise until it comes into contact with prong 118 of latch 113, whereby its movement is stopped at a definite position. The legend on handle 6 now indicates the off position as shown in Figure 13.

When pin C moves upward to cause the line of action between pins C and G to pass pin F, the parts may tend to stick or resist the movement of pin G due to wear or friction. To insure that pin G does move and the mechanism snap, an inside edge of eyes 107 in handle arms 9 and 10 comes into contact with pin G and forcibly moves it toward and beyond the dead center position.

Although I have described my invention with a certain degree of particularity, it is to be understood that the above disclosure has been made only by way of example as required by law and that many changes in the details of construction and the combination and arrangement of parts may be resorted to without departing from the spirit and scope of my invention as hereinafter claimed.

What I claim is:

1. A hand operated switch comprising a base, a housing of insulating material attached to the base, having an outer wall, and side walls extending therefrom toward the base; a plurality of parallel conducting paths on the outside of the outer wall each comprising in series a first terminal element, a current heated element of a thermal overload device, a pair of spaced stationary contacts, and a second terminal element; and a thermal overload device on the inside of the outer wall having a portion extending outwardly through the outer wall and heated by the heating element a mechanism frame secured to the base under the outer wall; a snap mechanism mounted on the mechanism frame and under the outer wall and enclosed by the side walls and comprising a snap element reciprocable with snap movements; a reciprocator extending from the snap element outwardly through a first aperture in the outer wall and between the stationary contacts and carrying bridging contacts outwardly of the stationary contacts aligned therewith for mutual cooperation upon reciprocation of the snap element; the mechanism comprising a pair of fiat sheet metal handle arms extending therefrom outwardly through a pair of slots in the outer wall, and a handle between the arms outward- 1y of the outer wall; the mechanism comprising means to effect said snap movements of the snap element upon to-and-fro movement of the handle arms by the handle; pin means in the handle and slot means in the flat arms, attaching the handle to the arms and operable by manual shifting of the pin for readily detaching the handle from the arms, angularly positionable rotary means attaching the bridging contacts to the reciprocator and rotatable to a position for readily detaching the bridging contact from the reciprocator, and threaded means for readily attaching the housing to the base and detaching it therefrom; whereby upon detaching the handle and bridging contacts, and by virtue of said apertures, the housing and the conducting paths and thermal devices and heating elements can be removed in unison from the base, leaving the mechanism undisturbed thereon for inspection.

2. A switch as described in claim 1 and in which the current heated element is a coil on the outside of the outer wall; and the thermal device is mounted on the inside of the outer wall and has a heatable element projecting through the outer wall into the coil; and the thermal device comprises a finger movable responsive to heating of the heated element by overload current in the conducting path; and the mechanism is actuated by movement of the finger to move the reciprocator with snap movement in the direction to unbridge the stationary contacts.

3. A switch comprising a base, a housing of insulating material having an outer wall spaced from the base; a switch operating mechanism between the wall and the base, comprising a reciprocable element; a plurality of pairs of spaced stationary contacts on the outside of the wall; a reciprocator of insulating material connected to the reciprocable element and reciprocable thereby and extending outwardly through an aperture on the housing wall between the pairs of stationary contacts, and carrying a corresponding plurality of bridging contacts outwardly of the stationary contacts, disposed to engage and disengage the pairs of stationary contacts upon reciprocation of the reciprocator; the housing wall formed to provide a correspond plurality of pairs of walled chambers on opposite sides of the reciprocator and open toward the reciprocator; the reciprocator formed to provide a fourth wall for all the pairs of chambers; whereby the engagement and disengagement of the contacts occurs in the chambers.

4. A switch as described in claim 3 and in which the reciprocator is formed to provide also barrier walls between the bridging contacts carried thereby.

5. In a switch comprising a housing of insulating material and formed to provide a plurality of pairs of walled chambers closed on three sides and open towards its pair; a corresponding plurality of pairs of stationary contacts supported in spaced relation onthe housing and having at least a portion of each disposed in one of the walled chambers; a reciprocator carrying a corresponding plurality of bridging contacts; operable means to reciprocator to cause all of the bridging contacts to bridge and unbridge the portions of respective pairs of stationary contacts disposed in the walled chambers; the reciprocator being of insulating material and formed to comprise a bar extending between the open sides of all of the walled chambers; and having a portion formed for connection to the operable means.

6. A switch as described in claim 5 and in which the reciprocator bar is provided with barrier walls between each of the bridging contacts carried thereby.

7. A switch as described in claim 5 and in which the reciprocator is formed to provide fourth wall for all of the pairs of walled chambers of substantially the same height when the stationary contacts are unbridged.

8. A hand operated switch comprising movable and stationary contacts; a mechanism operable to engage and disengage the contacts; a pair of spaced handle arms for operating the mechanism; a handle between the arms; means for readily attaching the handle to the arms and detaching it therefrom, comprising hook portions on each arm at opposite sides of the handle provided by axially aligned circular perforations opening into parallel slots; a round pin mounted on the handle for manual axial movement thereon; the pin having a pair of longitudinally spaced large diameter portions to slidingly fit the arm perforations, and having a pair of small diameter portions, both at the same longitudinal side of the large perforations and adjacent thereto and of a diameter slightly smaller than the width of the slots; the pin being movable axially, and when in a first axial position, the large diameter portions of the pin projecting through the arm perforations, thereby attaching the handle to the arms; and when in a second axial position the small diameter portions being disposed opposite to the slots, whereby the pin and handle may be detached from the arms by moving the handle to withdraw the small diameter portions of the pin outwardly through and out of the slots; and means yieldably maintaining the pin in said first axial position comprising a radially extending projection on the pin abutting a portion of the handle, and a spring reacting between the handle and the pin and yieldably maintaining the projection in said abutting condition.

9. A switch as described in claim 8 and in which, at least one of the arms has a finger which when the large diameter portions of the pin are in the arm perforations is disposed between inner and outer abutments provided on the handle to prevent rocking of the handle on the pin, and which when the handle is moved to withdraw the small diameter pin portions out of the slots, the inner abutment is moved with the handle to a position that clears the finger and permits the handle and the small diameter portions of the pin to be removed outwardly away from the arms to detach the handle from the arms.

10, A switch as described in claim 8 and in which, the mechanism is mounted in a housing and is operated by to and fro movement of the arms, and the housing has a shoulder which is adjacent to the arms when they have been moved to operate the mechanism to disengage the contacts; and the pin is rotatable in the handle; and the handle has a locking bar connected to the pin and disposed at one side of the handle; and the locking bar has a portion normally projected into a recess in the handle; and the said portion is removed from the recess in said second axial position of the pin, and the locking bar is then rotatable with the pin to dispose a portion of the locking bar behind the projection to prevent movement of the handle and arms that operates the mechanism to engage the contact.

11. A hand operated switch comprising a frame supporting stationary contacts; a reciprocator carrying movable contacts, normally disengaged from the stationary contacts; a snap mechanism for moving the reciprocator to engage the contacts with snap action, the snap mechanism comprising; an elongated latch pivoted at an intermediate point on a first pin stationary on the frame, and the latch at one side of the pivot normally latched against pivoting by a trip mechanism, and carrying a fulcrum pin on the other side of its pivot; a reciprocator pin on the reciprocator; a two'leg bell-crank connected at an intermediate point to the reciprocator pin, and one leg pivoted on a second pin stationary on the frame, and the other leg carrying a bell crank pin; a normally broken toggle comprising twolinks connected together at one end by a toggle pin and at their other ends con nected respectively to the bell-crank pin and the fulcrum pin; a handle arm pivoted at an intermediate point on the said second stationary pin and at one end provided with a handle and at the other end carrying an arm pin; the toggle pin and arm pin disposed to have a center line therebetween normally above the fulcrum pin; a tension 15 snap spring connecting the toggle pin and arm pin and acting along said line; the snap spring force on the toggle pin being transmitted to the bell-crank pin through a said toggle link and tending to pivot the bell-crank on the second stationary pin to thereby move the reciprocator pin and reciprocator in the contact disengaging di rection, and a first stop limiting pivoting of the bell-crank, in that direction; the handle arm being manually pivotable on the second stationary pin in a direction to cause the line of action of the snap spring to move below the fulcrum pin and substantially straighten out the toggle, and the toggle thereby pivoting the bell-crank on the second stationary pin and moving the reciprocator pin and reciprocator in the direction to effect engagement of the contacts, and a second stop for limiting pivoting of the bell-crank in that direction.

12. A switch and snap mechanism as described in claim 11 and in which the normal pivoted position of the handle arm before snap action is determined by a portion of the latch beyond its fulcrum pin engaged by the arm pin.

13. A switch and snap mechanism as described in claim 11 and in which, after snap action has occurred to engage the contacts, the handle arm is pivotable on the second stationary pin in the reverse direction, and the arm pin then causes the line of spring action to move above-the fulcrum pin; and the toggle is thereby again broken, and the bell crank is thereby pivoted back to its normal position, disengaging the contacts with snap action.

14. A switch as described in claim 11 and in which the handle arm has a portion adjacent to a portion of the toggle when the said line of action is below the fulcrum pin, and which, when the handle is moved to cause the line of action to be above the fulcrum pin, will engage the said portion of the toggle and initiate movement thereof in the collapsing direction upon failure of the toggle to be so moved by the snap spring.

15. A switch and snap mechanism as described in claim 11 and in which the latching of the said end of the latch is effected by a notch in the end of the latch engaged with a portion of a trigger pivotally supported on the frame and the trigger portion is held in engagement with the notch by a trigger spring; and means is provided to pivot the trigger against the trigger spring force upon the occurrence of overload current in the engaged contacts to release the latch notch; and the said snap spring acting through the toggle link that is between the toggle pin and fulcrum pin, pivots the latch on the first stationary pin and thereby moves the fulcrum pin below the line of action of the snap spring; whereupon the snap spring as aforesaid in such case moves the reciprocator to disengage the contacts with snap action.

16. A switch and snap mechanism as described in claim 15 and in which the pivoted trigger comprises an arm extending from the pivot, and the means to pivot the trigger comprises a thermo-responsive device having a finger that is snap-moved upwardly from a normal position, by a device spring upon occurrence of overload, and an intermediate element rests upon the finger between the finger and the trigger arm and is raised by the finger and an upper portion of the intermediate element engages and pivots the trigger arm.

17. A switch and snap mechanism as described in claim 16 and in which the handle arm has a portion adjacent to an upper portion of the intermediate element; and after tripping on overload and disengaging of the contacts and raising of the intermediate element upward by the device finger, the handle arm is pivotable to cause said adjacent portion to engag'e said upper portion of the intermediate element and move it, and the device finger on which it rests, downwardly, to reset the device finger to normal position.

18. A switch comprising stationary contacts; reciprocably movable contacts to engage and disengage the stationary contacts; a pivoted latch carrying a fulcrum pin; a trigger and a thermo-responsive device for moving the trigger from a normal position upon occurrence of overload in the engaged contacts; the latch being latched against pivoting by a portion of the trigger in its normal position; a snap mechanism connected to the movable contacts to reciprocate them comprising a pivoted handle arm having a normal position and connected to pivoted elements of the mechanism by a tension spring normally on a line of action at one side of the fulcrum, the elements reacting by spring tension upon the fulcrum and thereby normally holding the movable contacts reciprocated to disengaged position; the line of action of the spring being shiftable to the other side of the latch carried fulcrum upon manual pivoting of the handle arm from its normal position in one direction, the element then reacting by spring tension upon the fulcrum to cause the movable contacts to be moved to contact engaged position with snap action; the latch, upon being unlatched by the trigger when it is moved from normal position, being pivotable by the reaction of the spring to shift the latch carried fulcrum to a position at which the line of action of the spring is on the said one side of the fulcrum, to cause the elements to react by spring tension on the fulcrum and return the movable contacts to disengaged position.

19. A switch and mechanism as described in claim 18 and in which with the contacts engaged, pivoting of the handle arm in the other direction shifts the line of action of the spring above the latch-carried fulcrum and the element react by spring pressure on the fulcrum to move the movable contacts to disengage position.

20. A switch and mechanism as described in claim 19 and in which after unlatching of the latch by movement of the portion of the trigger from its normal position, means is provided to effect restoring of the trigger portion to normal position and to effect relatching of the latch thereon, operable by pivoting of the handle in the said other direction beyond the position at which the movable contacts were moved to disengaged position.

21. A hand operated switch comprising a frame supporting stationary contacts; a reciprocator carrying movable contacts, normally disengaged from the stationary contacts; a map mechanism for moving the reciprocator to engage the contacts, with snap action, the mechanism comprising; an elongated latch pivoted at an intermediate point on a first pin stationary on the frame, and the latch at one side of the pivot normally latched against pivoting by a trip mechanism, and carrying a fulcrum pin on the other side of its pivot; a reciprocator pin on the reciprocator; a first connecting element between the reciprocator pin and a second pin stationary on the frame; a second connecting element extending from the reciprocator pin and carrying a connection pin; a normally broken toggle comprising two links connected together at one end by a toggle pin and at their other ends connected respectively to the connection pin and the fulcrum pin: a handle arm pivoted at an intermediate point on the second stationary pin and at an end provided with a handle and at the other end carrying an arm pin; the toggle pin and arm pin disposed to have a center line therebetween normally above the fulcrum pin, a tension snap spring connecting the toggle pin and arm pin and acting along said line; the snap spring force on the toggle pin being transmitted to the said connection pin through a said toggle link and tending to pivot the first and second connecting elements and connection pin around the second stationary pin to thereby move the reciprocator pin and reciprocator in the contact disengaging direction; and a first stop limiting movement of the reciprocator in that direction; the handle arm being manually pivotable on the second stationary pin in a direction to cause the line of action of the snap spring to move below the fulcrum pin and substantially straighten out the toggle and the toggle thereby pivoting the connection pin and connecting elements on the second stationary pin and moving the reciprocator pin and reciprocator in the direction to engage the contacts, and a second stop limiting movement of the reciprocator in that direction.

22. A switch as described in claim 11 and in which the handle arm has a portion adjacent to a portion of the toggle when the said line of action is above the fulcrum pin, and which, when the handle arm is moved to cause the line or" action to be below the fulcrum pin, will engage the said portion of the toggle and initiate movement thereof in the straightening out direction upon failure of the toggle to be so moved by the snap spring.

23. A hand operated switch comprising stationary contacts, and movable contacts movable to engage the contacts with snap movement by a snap mechanism; the snap mechanism comprising a pivoted handle element having a handle at one side of the pivot and a toggle comprising two parts pivotally connected at a toggle mid-point and the toggle having a normal bent condition and operable to go to substantially straightened condition, by an overcenter spring connected between a point on the handle element on the other side of the handle pivot and the mid point upon pivotal movement of the handle element in one direction; connections between the toggle element and the movable contacts, to snap the latter to engaged position upon straightening out of the toggle; a portion of the handle element on said other side of the handle pivot coming into engagement with an intermediate portion of the toggle to initiate straightening out thereof by the handle element upon said pivotal movement of the handle element upon failure of the over-center spring to do so.

24. In a hand operated switch, a housing comprising a base portion and a cover portion; movable and stationary contacts; a snap mechanism mounted on the base portion under the cover portion; a handle arm connected to the mechanism extending outwardly through an aperture in the cover portion; a handle element on the outer end of the handle arm; the snap mechanism being operable to move the movable contacts to enage or disengage the stationary contacts upon alternate movements of the handle arm in said aperture by said handle; a finger pivoted on the handle by pivot means providing for axial and rotary movement of the finger; a spring normally constraining the finger to move to one axial position, and in that position having a portion engaged with positioning means on the handle preventing rotary movement of the finger; manually operable means to shift the finger in the other axial direction to permit manual rotation of the finger to a second position; the finger in said second position engageable with a shoulder on the housing cover portion and constituting a stop preventing movement of the handle and handle arm.

25. A switch comprising three pairs of stationary contacts; a reciprocator of insulating material carrying a bridging contact for each pair of stationary contacts; a pivoted handle; a snap mechanism operable by pivoting movements of the handle in alternate directions to on and ofl positions to elfect reciprocations of the reciprocator to bridge and unbridge the pairs of contacts; the mechanism comprising a pair of triggers extending from a rotatably supported pin and spaced apart in parallel relation; three thermally activatable devices comprising respective fingers spaced apart in alignment; means giving snap movements to the fingers respectively when the respective devices are activated; a fiat thin bar of insulating material, the ends of the bar projecting through spaced apart stationary slots and the bar having no connection with other parts and being free floating and slidable in the slots; the bar having spaced apart side edges; one edge having three recesses embracing the three fingers respectively to position the bar longitudinally and laterally in a normal position; the other edge being normally adjacent to the said pair of triggers; the snap movement of either one or more of the fingers moving the bar in the slots and rocking it around a finger not having made snap movement and causing its other edge to move and engage and rotate the triggers; the mechanism comprising means activated by the rotated triggers to eifect reciprocation of the reciprocator to unbridge the contacts; the handle upon pivoted movement in the off direction and somewhat beyond the 01f position to a resetting position, engaging the said other edge of the bar and moving the bar to restore it to its normal position and to cause it to restore the snapped finger or fingers to normal unsnapped positions; and means restoring the arm back to its ofi position after resetting.

26. A hand operated switch comprising stationary contacts, and movable contacts movable to enage and disengage the contacts With snap movement by a snap mechanism; the snap mechanism comprising a pivoted handle element having a handle at one side of the pivot and a toggle comprising two parts pivotally connected at a toggle mid-point and the toggle operable between a collapsed condition and a substantially straightened condition; by an over-center spring connected between a point on the handle element on the other side of the handle pivot and the toggle mid-point connections between the toggle element and the movable contacts, to snap the latter to disengage position upon collapse of the toggle; and upon pivotal movement of the handle in one direction a portion of the handle element on said other side of the handle pivot comes into engagement with an intermediate portion of the toggle to initiate collapse thereof by the handle element upon failure of the over-center spring to do so.

References Cited in the file of this patent UNITED STATES PATENTS 1,952,039 Frank et al Mar. 20, 1934 2,001,513 Zurcher May 14, 1935 2,006,954 Kuhn July 2, 1935 2,126,412 Rowe Aug. 9, 1938 2,230,713 Butler Feb. 4, 1941 2,242,717 Cole et al. May 20, 1941 2,248,387 Rosing et al. July 8, 1941 2,263,208 Getchell Nov. 18, 1941 2,265,004 Pierce et al. Dec. 2, 1941 2,329,362 Swingle Sept. 14, 1943 2,426,129 Van Valkenburg et al. Aug. 19, 1947 2,490,514 Favre Dec. 6, 1949 2,663,777 COX Dec. 22, 1953 2,664,482 Goudy et a1 Dec. 29, 1953 2,689,896 Kuhn et a1 Sept. 21, 1954 2,813,951 Kolb et a1. Nov. 19, 1957

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