US3590180A

US3590180A - Manually operated toggle-acting switch having a means for preventing assembly of the switch with the contacts of the switch in a circuit-closing condition

Info

Publication number: US3590180A
Application number: US9160A
Authority: US
Inventors: Jordan F Puetz; Joseph J Gribble; James P Schmiedel
Original assignee: Square D Co
Current assignee: Schneider Electric USA Inc
Priority date: 1970-02-06
Filing date: 1970-02-06
Publication date: 1971-06-29
Anticipated expiration: 1988-06-29
Also published as: CA928367A

Abstract

A manually operated switch having a toggle lever actuating mechanism included in a housing part which may be readily removed from a base carrying the stationary contacts of the switch to permit inspection of the current carrying contacts of the switch. The switch includes a slider which moves to an activated position when the housing part is removed from the base. The slider, when in the activated position, causes the levers of the toggle mechanism to move and be maintained in an OFF operating position so that the toggle mechanism must be reset after the housing is remounted on the base before the levers of the toggle mechanism can be moved to the ON position.

Description

United States Patent SWITCH HAVING A MEANS FOR PREVENTING ASSEMBLY OF THE SWITCH WITH THE CONTACTS OF THE SWITCH IN A CIRCUIT- Primary Examiner- Robert K. Schaefer Assistant Examiner-Robert A. Vanderhye Allorneys- Harold J. Rathbun and William H. Schmeling LO ING NDITI N I C C0 ABSTRACT: A manually operated switch having a toggle 10 Claims, 6 Drawing Figs. I

lever actuating mechanism included in a housing part which [52] [1.5. CI 200/50 A, may be readily removed f a base carrying the Stationary zoo/153 ZOO/72 R contacts of the switch to permit inspection of the current car- [51] InLCl H0lh 9/22, rying contacts f the switch The Switch includes a slider H011 3/46 which moves to an activated position when the housing part is [50] Field of Search 1. 200/153 G, removed f the base The Slider when in the activated posi 71, 72 50 A, 144 R; 337/7 tion, causes the levers of the toggle mechanism to move and be maintained in an OFF operating position so that the toggle [56] References Cited mechanism must be reset after the housing is remounted on UNITED STATES PATENTS the base before the levers of the toggle mechanism can be 3,110,778 11/1963 Edmunds 200/50 A moved to the ON position.

I2 4 30 2 O 0 1Q 96 8 5O 7O 22 7 32 I4 PATENTEUJunasmn I 3,590 1 0 INVIiN'IOR JAMES R SCHMIEDEL MANUALLY OPERATED TOGGLE-AETHNG SWITCH HAVING A MEANS FOR PREVENTING ASSEMBLY OF THE SWITCH WITH THE CONTACTS OF THE SWITCH IN A CIRCUIT-CLOSING CONDITION This invention relates to a manually operated electric switch and more particularly, to an arrangement which will prevent the switch from being assembled with its contacts in a circuitclosing condition.

Switches known as manually operated motor starters are frequently used in unsophisticated circuits, known as branch circuits, to control the energization of electric motors, electromagnetic clutches and the like, from a single control station. Frequently, branch circuits are provided with a switching arrangement, known as a disconnect switch, which is capable of carrying the load current of the circuit and may be incapable of interrupting the starting load current through the circuit. Acceptable maintenance practice requires that starters controlling the operation of motors and the like be periodically inspected so that the contacts can be replaced when necessary to assure that the motor will operate without interruption. To accommodate the inspection of the switching contacts motor starters usually are provided with an arrangement whereby the starters may be disassembled to expose the switching contacts. A switch or motor starter incorporating the features of the present invention includes a toggle-acting operating mechanism and thus will have basically two states of operation wherein the toggle mechanism will either maintain the switching contacts in a circuit-closing position or permit the switching contacts to move to a circuit-opening position. Prudent safety practices dictate that before a manually operated motor starter is disassembled for inspection purposes, the disconnect switch be opened so that the circuits wherein the motor starter is included are deenergized. After the inspection of the motor starter is completed, and the motor starter is reassembled, the main disconnect is then closed to reenergize the motor starter circuit. If the contacts of the motor starter are in the circuit-opening position when the disconnect switch is reclosed, the above may be safely accomplished. However, as the manually operated motor starter incorporating the features of the present invention is of the toggle-acting type, the possibility arises that the motor starter may be reassembled with the toggle mechanism in the ON position. If the reassembly of the motor starter should be attempted when the toggle mechanism is in its ON condition and the main'disconnect switch is in a circuit-completing condition, the reassembly of the motor starter will complete the circuit to the electrical load which is normally controlled by the motor starter. This could result in disasterous consequences if the load is an electric motor, as the motor starter would be reassembled while the motor was drawing its inrush starting current which greatly exceeds its running current requirements. Under these conditions injury to the person reassembling the motor starter is possible. Another condition which may be encountered is that the motor starter is reassembled with the toggle mechanism in the ON condition while the main disconnect switch is in the circuit-opening position. Under these conditions if the operating condition of the motor starter is not detected, the closure of the disconnect switch may cause an unexpected energization of the motor or circuit controlled by the motor starter which may result in damage to machinery or material in a process line. The switch or manual starter according to the present invention includes an arrangement which will prevent the motor starter from being assembled when the contacts are in a circuit-closing position and requires that the operating buttons of the switch be moved to a RESET position after the motor starter is assembled before they are capable of being moved to an ON position to minimize the possibility of injuryto persons and damage to material and equipment, as will be apparent from the following objects.

It is an object of the present invention to provide a manually operated switch that has a toggle-lever-type actuating iechanism with an arrangement that will automatically move the levers of the toggle mechanism to a tion when the switch is disassembled.

An additional object is to provide a manually operated switch with an arrangement which will prevent the contacts of the switch from being in a circuit-closing position while the switch is assembled.

A further object is to provide a manually operated switch, such as a manually operated starter, with a housing that is detachably secured on a base that carries the stationary contacts of the switch and provides an enclosure for a toggle-acting mechanism that is arranged to control the movement of a carrier that supports the movable contacts for the switch with a means which will automatically cause the levers of the toggle mechanism to move to positions which will cause the movable contacts of the switch to be separated from the stationary COIF tacts when the housing is detached from the base so as to prevent the housing from being assembled on the base with the contacts of the switch in a circuit-closing position.

Further objects and features of the invention will be readily apparent to those skilled in the art from the specification and appended drawing illustrating certain preferred embodiments in which:

FIG. 1 is a side view partly in cross section of a manually operated switch incorporating the features of the present invention.

FIG. 2 is a top end view of a portion of the switch in FIG. 1 with a portion of the switch in cross section to illustrate a slide used in the switch in FIG. 1.

FIG. 3 is a perspective view of a pair of slides and a latch lever used in the switch in FIG. 1.

FIG. 4 is a diagrammatic view illustrating the positions of the levers of a toggle mechanism of the switch in FIG. 1 in a tripped position. 1

FIG. 5 is a diagrammatic view illustrating the positions of the levers of a toggle mechanism of the switch in FIG. 1 in a RESET condition when the levers are in an ON position.

FIG. 6 is a diagrammatic view illustrating the position of the levers of a toggle mechanism of the switch in FIG. 1 in a RESET condition when the levers are in an OFF position.

The switch 10, as shown in the drawing, includes an upper section or housing 12 and a lower section or base 14 which are secured together. The switch 10 is more fully described in copending application, Ser. No. 9203, filed Feb. 6, 1970, which has been filed by the inventor Jordan F. Puetz concurrently herewith and has been assigned to the assignee of the present application. As disclosed in the Puetz application, the base 14 is arranged to be mounted on a vertical panel, not shown, and includes a section 16 that is suitably compartmented and includes means which will respond to an excess current flow through a circuit to be monitored. The particular means in the section 16 includes three melting alloy-type current-responsive elements, each of which is positioned in a compartment and includes a solder-type current-responsive unit that has a heater element connected in series with a circuit to be monitored and a ratchet wheel which is held stationary when the current flow through the heating element does not exceed a preselected value and which is released to rotate upon excessive current flow through the unit. The release of the ratchet wheels will cause any one of the plurality of sliders, not shown, to move in the section 16 and thereby move a lever and a slider 80, which is functionally shown in FIG. 3, to cause a disengagement between a hook 20 on a release lever 22 and a hook 24 on a trip lever 26. The trip lever 26 is part of a toggle mechanism 28 and is included within a cavity 30 in the housing 12. Also included within the cavity 30 is a movable contact carrier 32 and a means which will prevent assembly of the switch 10 with the contacts in a circuit-closing position, as will be hereinafter described.

The movable contact carrier 32 is suitably guided by portions of the housing 12 to move in a linear path along an axis 36 in the cavity 30 and moves from a position wherein a pair of movable contacts 38, carried by the movable contact carrier 32, are separated from a pair of stationary contacts 40 of predetermined posithe switch. to a position wherein the movable contacts 38 bridge the stationary contacts 40. The movable contact carrier 32 is moved by the toggle mechanism 28 against the force of suitable springs, not shown, which react upon a stabilizing bar 42 in a manner described in the Puetz application. The toggle mechanism 28 includes a toggle lever 44, an operating lever 46, the trip lever 26, a toggle spring 48, a toggle latch lever 50, which is biased by a spring, not shown, and a means for moving the operating lever 46 which in the embodiment shown includes an OFF-RESET button 52 and an ON button 54. The housing 12 provides a support for a main pivot 56 of the toggle mechanism 28.

The operating lever 46 and the trip lever 26 are rotatable about the main pivot 56'and have arm portions extending in opposite directions from the pivot 56. The arm portion ofthe trip lever 26 extending to the left of the pivot 56 in FIGS. 4-6 carries the hook 24. The arm portion of the trip lever 26 extending to the right of the main pivot 56 includes an auxiliary pivot 58. The operating lever 46, which has arm portions extending in opposite directions from the main pivot 56, has a pin 60 secured on an end of the arm portion extending to the right 'of the pivot 56 and a pin 62 secured on the end of the arm portion extending to the left of-the main pivot 56. The OFF-RESET button 52 and the ON button 54 are respectively secured through a slotted connection, not shown, with pins that are respectively carried on the arm portions of the operating lever 46 to the left and right of the main pivot 56 so that the buttons 52 and 54, which are suitably guided for vertical movement by portions of the housing 12, will cause the operating lever 46 to move in a clockwise direction when the ON button 54 is depressed and in a counterclockwise direction of rotation when the OFF button 52 is depressed.

The operation of the toggle mechanism 28 is as follows. The levers of the toggle mechanism 28 are shown in the OFF- 4 RESET condition in FIG. 6 wherein engagement between the hooks and 24 causes a spring 64 to be compressed and maintains thetrip lever 26 against a clockwise rotation and positions the trip lever 26 so that the auxiliary pivot 58 is located above a centerline indicated by a broken line 66 which extends through the main pivot 56. The button 52, which has been previously depressed, positions the operating lever 46 so the pin 60 is located above the centerline 66. The toggle spring 48 has its opposite ends connected between the pin 60 and a pin 68 that is carried on an end of an arm portion of the toggle lever 44 on the left side of the pivot 56. The position of the pin 60 above the centerline 66 causes a line of centers between the

pins

60 and 68 to be disposed above the centerline 66 so that the toggle spring 48 causes and end on the toggle lever 44 to be positioned on the auxiliary pivot 58 so that the pin 68 is above the centerline 66 and an actuating portion 70 on the toggle lever 44 to be positioned so that the movable contact carrier 32 is moved relative to the base 14 by springs, not shown, to a position wherein the movable contacts 38 are separated from the stationary contacts 40. When the toggle mechanism 28 is in the OFF position, a stop carried by the toggle lever 44 engages an upper edge on the trip lever 26 to prevent further movement of the toggle lever 44 and the operating lever 46 by the toggle spring 48.

The toggle mechanism 28 is moved from the OFF-RESET position shown in FIG. 6 to the ON position shown in FIG. 5

by depressing the button 54. The depression of the button 54 causes the operating lever 46 to rotate about the pivot 56 in a clockwise direction so that the pin 60 is positioned beneath the centerline 66 which causes the line of centers between the pin 60 and the pin 68 to be disposed beneath the center of the pivot 56 whereby the toggle spring 48 causes the toggle lever 44 to rotate about the auxiliary pivot 58 and position the pin 60 below the centerline 66. The movement of the toggle lever 44 causes the actuating portion 70 to move toward the base 14 so that the movable contact carrier 32 moves and causes the movablecontacts 38 to engage the stationary contacts 40 with a firm engagement as the movable contacts 38 compress the springs 72 which engage the movable contacts 38. The movement of the levers of the toggle mechanism 28 when positioned in the ON position is limited by a stop that is carried by the trip lever 26 which engages an upper surface portion on the toggle lever 44. 9

in the event of an excess current flow through any one or all of the overload elements in the section 16, the levers of the toggle mechanism 28 will automatically move to the TRIPPED position as follows. When the toggle mechanism 28 is positioned in the ON and RESET position, the spring 64, which biases the TRIP lever 26 in a clockwise direction of rotation, will be compressed,

pins

60 and 68 will be located below the centerline 66, and the auxiliary pivot 58 will be positioned above the centerline 66. The contact carrier 32 will be positioned by the portion 70 so that the stationary contacts 40 are bridged by the movable contacts 38. An excess current through any one or all of the overload elements will cause the release lever 22 to rotate about its pivots 74 in a clockwise direction of rotation. The pivots 74, shown in FIG/3, are rotatably supported by the housing 12. The lever 22 carries the hook 20 so that the rotation of the lever 22 causes the hook 20 to rotate clockwise and release the hook 24. The release of the hook 24 permits the TRIP lever 26 to be rotated by the force of spring 64 in a clockwise direction to a TRIPPED position. During the rotation of the TRIP lever 26 to the TlRlPPED position, the auxiliary pivot 58 will pass through a line of centers between the

pins

60 and 68 to a position below the centerline 66. The movement of the auxiliary pivot 58 to the TRIPPED position causes the toggle spring 48 to supply a force which rotates the toggle lever 44 in a clockwise direction and the operating lever 46 to rotate in a counterclockwise direction to a neutral position wherein the position of the operating lever 46 will cause the buttons 52 and 54 to be positioned so that their top surfaces are aligned in a single plane and visually indicate from the exterior of the switch 10 that the components of the switch it) have responded to a overload condition. Also, when the toggle mechanism 28 is in an overload position, the portion 70 will be in a fully retracted position so that the contact carrier 32 is moved to a position wherein the movable contacts 38 are separated from the stationary contacts 40.

As disclosed in the Puetz application, supra, the toggle latch lever 50 comprises a U-shaped member having a pair of arms pivotally mountedon members forming the TRIP lever 26. The arms of the latchlever'SO are interconnected by a bight portion 76. The latch lever 50 has a surface which is engaged by a portion on the operating lever 46 when the operating lever 46 is moved to the OFF position and a portion that is engaged by a portion 78 on the release lever 22. The toggle latch lever spring, not shown, surrounds the pivot for the toggle latch lever 50 and constantly urges the latch lever 50 in a clockwise direction of rotation in FIGS. 4-6.

The operation of the toggle latch lever 50 will now be described. When the levers of the toggle mechanism 28 are in the OFF position, a portion of the operating lever 46 will engage and rotate the latch lever 56 in a counterclockwise direction so that the bight portion 76 is out of engagement with a hook, not shown, on the toggle lever 44. When the levers of the toggle mechanism 28 are in the ON position, the operating lever 46 will be separated from the latch lever 50 so the spring will rotate the latch lever 50 in the clockwise direction to a position wherein the bight portion 76 is engageable with a hook on the toggle lever 44. When the button 52 is depressed to move the operating lever 46 from the ON position to the OFF position, the bight portion 76 will be maintained in engagement with the hook on the toggle lever 44 until the line of centers between the

pins

60 and 68 has passed a predetermined distance above the axis of the main pivot 56 before a portion on the operating lever 46 engages a surface on the latch lever 50 so the contact carrier 32 will be maintained in a position wherein the movable contacts 38 are in tight engagement with the stationary contacts 40 and positive pressure is maintained by the movable contacts 38 and stationary contacts 40 as the toggle mechanism 28 passes through a line of toggle centers which would otherwise provide zero pressure between the movable contacts 38 and stationary contacts 40. When the components of the switch respond to an overload condition, as has been previously described, which causes the hook to rotate in a clockwise direction, the portion 78 of the release lever 22 is arranged to engage a portion on the latch lever 50 to rotate the lever 50 in a counterclockwise direction to release the engagement between the bight portion 76 and a hook on the toggle lever 44 so that the toggle lever 44 is free to rotate in a clockwise direction to the TRIPPED position, as has been previously described.

After the switch 10 has responded to an overload current condition, the components of the switch may be restored to the OFF-RESET position as follows. As previously indicated, the switch 10 will respond to an overload current condition and cause the buttons 52 and 54 to be aligned. The depression of the OFF-RESET button 52 from its aligned position with the button 54 will cause the operating lever 46 to rotate in a counterclockwise direction and cause the pin 62 to engage the upper surface of the trip lever 26 and move the trip lever 26 in a counterclockwise direction of rotation to the RESET position. The lever 46 has portions 47 thereon which are arranged to engage portions on the slider 80 which is part of the overload detecting means in the base 14 and move the slider 80 when the lever 46 rotates in a counterclockwise direction to reset the overload detecting means as described in the aforementioned copending Puetz application, Ser. No. 9203, filed Feb. 6, I970. In the event the solder in all of the overload elements within the section 16 has been solidified so that the ratchet wheels will no longer be free to rotate, the slider 80 will be maintained in its RESET position so that a spring 82 will move the release lever 22 to a position which will permit the hook 20 to engage the hook 24 and maintain the trip lever 26 in the RESET position, as previously described. In event the ratchet wheels are not held fixed, as may be caused when the device is prematurely reset, the release of the operating OFF-RESET button 52 will cause the slider 80 to move the release lever 22 as previously described. Thus the switch 10 will have a trip-free operation.

Thus the switch 10 as described will maintain a positive pressure between the switching contacts during the interval the levers of the toggle mechanism are passing through positions which would otherwise provide a zero output force on the movable contact carrier. Further, the toggle mechanism 28 of the switch 10 is arranged so that the operating buttons or rotatable lever will move to positions which indicate the switch has responded to an excess current condition.

A means 90, carried by the housing i2, is arranged to move the auxiliary pivot 58 from the RESET position shown in FIGS, 5 and 6 to the TRIP position shown in FIG, 4, when the housing 12 is separated from the base 14. The means 90 includes a slider 92, a spring 94 and a plate 96. As was described, the movement of the TRIP lever 26 to the TRIPPED position, causes the toggle lever 44 to rotate and be maintained in the deactivated position while the portion 70 is retracted and the movable contact carrier 32 moves to a position wherein the movable contacts 38 are separated from the stationary contacts 40. As most clearly illustrated in FIG. I, a portion of the slider 92 and the spring 94 is received in a cavity 98 within the housing 12. The slider 92, which is most clearly illustrated in FIG. 3, includes a pair ofguides H00 and 102 which are spaced on opposite sides ofa seat for the spring 94. The guides 100 and 102 are received in suitable slots in the walls of the cavity 98. The spring 94, which has its opposite ends positioned between a portion of the housing 12 and the seat on the slider 92, constantly urges a portion 104 on the slider 92 into engagement with the portion 78 on the release lever 22. The plate 96 is suitably secured to the housing by self-tapping screws 97 to maintain the spring 94 and a portion of the slider 92 including the guides H00 and 1102 within the cavity 98. The slider 92 additionally has a portion 106 that projects beyond the portion 104. The portion 106 is arranged to engage a portion of the base 14 when the housing 12 is secured in its properly assembled condition on the base 14 and cause the slider 92 to move upwardly within the cavity 98 so that the portion 104 is out of engagement with the portion 78 of the release lever 22. The means 90, which causes the toggle lever 44 to be moved to a position so that the contacts 38 are separated from the stationary contacts 40 when the housing 12 is detached from the base 14, operates as follows. When the housing 12 is secured to the base 14, the portion 106 will engage a portion of the base i4 and move the slider 92 to a retracted position where it is inoperative. During the removal of the housing 12 from the base 14, the portion 106 will be relieved of its engagement with portions of the base 14 so that the spring 94 causes the slider 92 to move downwardly, as in FIG. 1, and cause the portion 104 to engage the portion 78 of the release lever 22 and rotate the release lever 22 against the force supplied by the spring 82 in a clockwise direction, as in FIG. 4. The clockwise rotation of the release lever 22 will cause the hook 20 to move out of engagement with the hook 24 so that the trip lever 26 is released to rotate to its TRIPPED position by the spring 64. In this connection it should be noted that the portion 104 is arranged to move the portion 78 in a clockwise direction when the housing 12 is detached from the base 14. Similarly, when the switch responds to an excess current condition, the slider 80 will move in a downward direction in FIG. 3 and the spring 82 will cause the lever 22 to rotate in a clockwise direction to release the TRIP lever 26 so that the TRIP lever moves to the TRIPPED position The spring 94 is selected to exert a greater force on the lever 22 than the spring'82. Thus when the housing 12 is detached from the base I4, the spring 94 will overpower the spring 82 and cause the clockwise direction of the rotation of the release lever 22 in a manner described.

While certain preferred embodiments of the invention have been specifically disclosed, it is understood that the invention is not limited thereto, as many variations will be readily apparent to those skilled in the art and the invention is to be given its broadest possible interpretation within the terms of the following claims.

What we claim is:

1. In an electric switch the combination comprising: an insulating base having an open front, a plurality of pairs of stationary contacts mounted in a row on the base with the contacts of each pair equidistantly spaced on opposite sides of a centerline and accessible from the open front of the base, a housing removably mounted on the open front of the base, said housing having an internal cavity therein, a movable contact carrier supporting a plurality of movable contacts with each of said movable contacts disposed to engage and bridge the contacts of one of the pairs of stationary contacts when the contact carrier is in an operative position and to be separated from the-stationary contacts when the contact carrier is in an inoperative position, a toggle-acting operating mechanism positioned within the cavity by the housing, said operating mechanism including a main pivot, an auxiliary pivot, an operating lever, means providing access to the operating lever from the exterior of the housing for moving the operating lever about the main pivot between an OFF position and an ON position when a manual force is applied through the means to the operating lever from the exterior of the housing, a toggle lever rotatable about the auxiliary pivot between a deactivated and an activated position, said toggle lever having a portion engaging the contact carrier for moving the carrier from the inoperative position to the operative position when the toggle lever is moved from the deactivated position to the activated position, a toggle spring having its opposite ends connected between the operating lever and the toggle lever, said toggle spring providing a connection between the operat ing lever and the toggle lever for moving the toggle lever with an overcenter toggle action between its deactivated and activated positions when the operating lever is moved respectively between its OFF and ON positions and for maintaining the toggle lever and the operating lever respectively in the deactivated position and the OFF position when the operating lever is manually moved by said means to the OFF position and the manually applied force on the operating lever is removed, and for maintaining the toggle lever and the operating lever respectively in the activated position and the ON position when the toggle lever is moved to the ON position and the manually applied force on the operating lever is removed, and a means carried by the housing and operative only when the housing is separated from the base for moving the auxiliary pivot from a RESET to a TRIPPED position within the cavity and causing the toggle lever to move and to be maintained in the deactivated position when the housing is separated from the base.

2. The combination as recited in claim 1 wherein the toggle mechanism includes a trip lever that is rotatable about the main pivot between a TRIPPED position and a RESET position and provides the auxiliary pivot, and said means includes a releaseable latch having a portion engaging the trip lever for releasably maintaining the trip lever against rotation from the RESET position and the auxiliary pivot in a position so that thetoggle spring causes the toggle lever to respond to the movement of the operating lever.

3. The combination as recited in claim 2 wherein the means includes'a spring biased slider that engages a portion of the base and is moved to an inoperative position when the housing is mounted on the base and moved to an operative position wherein a portion of the slider engages a portion of the latch to move said portion of the latch out of its engaging position with the trip lever when the housing is separated from the base.

4. The combination as recited in claim 1 wherein the base includes a means responsive to an excess current flow through a circuit that includes the movable contacts when the contact carrier is in its operative position for moving the latch out of its engaging position with the trip lever when the housing is mounted on the base and an excess current flows through the movable contacts.

5. The combination as recited in claim 2 wherein the base includes a means responsive to an excess current flow through a circuit that includes the movable contacts when the contact carrier is in its operative position for moving the latch out of its engaging position with the trip lever when the housing is mounted on the base and an excess current flows through the movable contacts.

6. The combination as recited in claim 3 wherein the base includes a means responsive to an excess current flow through a circuit that includes the movable contacts when the contact carrier is in its operative position for moving the latch out of its engaging position with the trip lever when the housing is mounted on the base and an excess current flows through the movable contacts.

7. The combination as recited in claim 4 wherein the current responsive means includes a second slider that has a portion engageable with the releasable latch.

8. The combination as recited in claim 2 wherein the releasable latch is rotatably mounted on the housing and is biased by a spring to the latching position.

9. The combination as recited in claim 8 wherein the means includes a spring biased slider that engages a portion of the base and is moved to an inoperative position when the housing is mounted on the base and moved to an operative position wherein a portion of the slider engages a portion of the latch to move said portion of the latch out of its engaging position with the trip lever when the housing is separated from the base.

10. The combination as recited in claim 9 wherein the base includes a means responsive to an excess current flow through a circuit that includes the movable contacts when the contact carrier is in its operative position for moving the latch out of its engaging position with the trip lever when the housing is mounted on the base and an excess current flows through the movable contacts.

Claims

1. In an electric switch the combination comprising: an insulating base having an open front, a plurality of pairs of stationary contacts mounted in a row on the base with the contacts of each pair equidistantly spaced on opposite sides of a centerline and accessible from the open front of the base, a housing removably mounted on the open front of the base, said housing having an internal cavity therein, a movable contact carrier supporting a plurality of movable contacts with each of said movable contacts disposed to engage and bridge the contacts of one of the pairs of stationary contacts when the contact carrier is in an operative position and to be separated from the stationary contacts when the contact carrier is in an inoperative position, a toggle-acting operating mechanism positioned within the cavity by the housing, said operating mechanism including a main pivot, an auxiliary pivot, an operating lever, means providing access to the operating lever from the exterior of the housing for moving the operating lever about the main pivot between an OFF position and an ON position when a manual force is applied through the means to the operating lever from the exterior of the housing, a toggle lever rotatable about the auxiliary pivot between a deactivated and an activated position, said toggle lever having a portion engaging the contact carrier for moving the carrier from the inoperative position to the operative position when the toggle lever is moved from the deactivated position to the activated position, a toggle spring having its opposite ends connected between the operating lever and the toggle lever, said toggle spring providing a connection between the operating lever and the toggle lever for moving the toggle lever with an overcenter toggle action between its deactivated and activated positions when the operating lever is moved respectively between its OFF and ON positions and for maintaining the toggle lever and the operating lever respectively in the deactivated position and the OFF position when the operating lever is manually moved by said means to the OFF position and the manually applied force on the operating lever is removed, and for maintaining the toggle lever and the operating lever respectively in the activated position and the ON position when the toggle lever is moved to the ON position and the manually applied force on the operating lever is removed, and a means carried by the housing and operative only when the housing is separated from the base for moving the auxiliary pivot from a RESET to a TRIPPED position within the cavity and causing the toggle lever to move and to be maintained in the deactivated position when the housing is separated from the base.

2. The combination as recited in claim 1 wherein the toggle mechanism includes a trip lever that is rotatable about the main pivot between a TRIPPED position and a RESET position and provides the auxiliary pivot, and said means includes a releaseable latch having a portion engaging the trip lever for releasably maintaining the trip lever against rotation from the RESET position and the auxiliary pivot in a position so that the toggle spring causes the toggle lever to respond to the movement of the operating lever.

3. The combination as recited in claim 2 wherein the means includes a spring biased slider that engages a portion of the base and is moved to an inoperative position when the housing is mounted on the base and moved to an operative position wherein a portion of the slider engages a portion of the latch to move said portion of the latch out of its engaging position with the trip lever when the housing is separated from the base.