US2472275A

US2472275A - Electric switch

Info

Publication number: US2472275A
Application number: US585362A
Authority: US
Inventors: Bollmann Karl; Meier Hans
Original assignee: Landis and Gyr AG
Current assignee: Landis and Gyr AG
Priority date: 1943-12-27
Filing date: 1945-03-28
Publication date: 1949-06-07
Anticipated expiration: 1966-06-07
Also published as: GB588738A; FR908294A; DE845975C; NL61224C; CH240892A; BE459993A

Description

June 1949. K. BOLLMANN r-: r 2,472,275

ELECTRIC SWITCH Filed March 28, 1945 2 Sheets$heet 2 lll'lll I I a I I l I fig z INVENTO/PS BY )ffpyw' A rzomzzys.

Patented June 7, 1949 ELECTRIC SWITCH Karl Bollmann, Zurich, and Hans Meier, 2113, Switzerland, assignors toLandis & Gyr, A. G., Zug, Switzerland, a body corporate of Switzerland Application March 28, 1945, Serial No. 585,362 In Switzerland December 2'7, 1943 Section 1, Public Law .690, August 8, 1946 Patent expires December 27,1963

8 Claims. (Cl. 200-88) The present invention relates to an electric switch or circuit breaker, and more particularly to such a device of the type having a switch magnet and an interference switch in its circuit.

Objects and advantages of the invention will be set forth in part hereinafter and in part will be obvious herefrom, or may be learned by prac tice with the invention, the same being realized and attained by means of the instrumentalities and combinations pointed out in the appended claims.

The invention consists in the novel parts, constructions, arrangements, combinations and improvements herein shown and described.

The accompanying drawings, referred to herein and constituting a part hereof, illustrate two embodiments of the invention, and together with the description, serve to explain the principles of the invention.

0f the drawings:

Figure 1 is a part fragmentary, generally schematic, perspective view of a typical and an illustrative embodiment of the present invention; and,

Figure 2 is a part fragmentary, enerally schematic, perspective View of a second embodiment of the present invention.

In electric switches or circuit breakers of the type mentioned above it is customary to provide means for effecting a rapid action switching-off operation which is produced by an overload upon the mechanism, due either to short-circuit or too high a temperature. Push-button control means have been provided for resetting the parts for normal action after such a rapid action switchingoif operation, but there is the diificulty in these arrangements that they may be switched ofi at any time by the push button, and this may give interruptions in service and render diflicult the checking of actual troubles in the power network.

It is the object of the present invention to obviate these disadvantages in conventional circuit breakers of this type by the provision of mechanisms wherein the push-button is inoperative except for switching-in operations.

Referring now in detail to the illustrative embodiments of the invention shown by way of example in the accompanying drawings, and referring first to the embodiment of Figure 1, there is shown a circuit breaker having the normally stationary contact I and the movable contact side 2 forming one pole of what may be a plural pole switch, one pole only of which is shown in the drawings. The normally stationary con- 2 tact l is urged to the right (as viewed in Figure 1) by a spring to and is held in its normally stationary position to the left against the tension of the spring by means of a nose or projection 3 on member I which engages rotatable rod 4 which has a flat portion for release of the projection 3. The rod 4 is rotatable about its longitudinal axis by means of armature 5 of a blower magnet 6, the armature being spring biased away from the magnet as shown. The movable contact 2 is mounted on the armature I of a switch magnet 8, the armature being pivotally mounted on axis 9 and biased away from magnet 8 by a spring It). An interference switch II is provided in the circuit of the switch magnet 8. The numeral l2 denotes the push-button for re-switching-in the switch.

As shown the push-button I2 is urged to the left by spring 13 and is pivotally secured at H to a bail lever 55 which is mounted for rotary or pivotal movement upon a shaft to. At the upper end of lever 15 a bail I3 is pivotally mounted thereon at H, and the bail is provided with a pusher lever IQ for each pole i, 2 which the circuit breaker has. Bail l3 and lever is are urged in a clockwise direction about axis 91 by means of a leaf spring 20 which is secured to an abutment 28 of bail lever l5. Each pusher lever l9 has a shoulder 25 and a sliding face 22 to cooperate with the contact i as will be hereinafter described, and one of the pusher levers l9 (assuming that the switch has plural poles) is provided with a depending arm 23 to cooperate with an abutment 2d extending outwardly from armature l.

A pawl lever 26 is pivotally mounted about ,an axis 25 and is provided with a shoulder 21 to engage abutment 23 of bail lever l5. Pawl lever 26 is urged in a counter-clockwise direction about axis 25 by means of spring 29, and has a nose 33 engageable with a long element of interference switch II to open the switch. At its upper end v awl lever 26 has a cross member 32 with a depending lug 3| for engagement with the rear end portion lb of each contact I which the switch may have.

Thermally responsive means are provided in operative connection with ball lever l5 and pawl lever 26. The thermally responsive'means is a bimetallic strip 33 moveable in the direction of the arrow directly above it in Figure 1 upon becoming heated. The operative connection of strip 33 with the mechanism already described includes a rod 34 rotatable about its longitudinal axis and a key bolt 35 adjustably mounted on a aeraavo lever arm adapted to turn the rod 34. The key bolt 35 is urged to the right in Figure 1 by spring 36 and extends through an aperture in a stationary wall 38, collar 31 on the key bolt engaging the wall at times when the bimetallic strip 33 is not at sufllcient temperature to engage the end of the key bolt and push it to the left. A lever 39 is adapted to abut the rod 3 and to pass over a flat portion thereof when the rod is turned by action of bimetallic strip 33 on key bolt 35. Lever 39 has integrally associated therewith a lever M having abutments it and M, and the

entire member

39, 32 is mounted for free rotation on shaft it. A leaf spring 33 mounted on stationary wall 38 engages the

lever member

39, 42 to urge it in a counter-clockwise direction. The abutment Q3 of lever 32 is adapted to engage a pin M extending from the side of pawl lever 23, and abutment ll is engageable with portion 23 of bail lever i 5.

Turning now to the operation of the embodiment of the invention shown in Figure l, and with the switch in closed position as there shown, each of the normally stationary contact parts i are locked by the abutment of nose 3 against rod 3, the bail lever it! bears against shoulder 27 of pawl lever 26, the pusher levers i9 are held to the right and out of engagement with contacts 9 by the engagement of abutment 2 3 with arm 23, the interference switch ii is closed, and the abutments l3 and ii of lever G2 are out of engagement with levers 23 and i5 respectively because lever 39 is in engagement with rod 33.

In a normal circuit breaking of the switch the contact parts 2 are pivoted about aXis 3 away from the normally stationary contacts i, and the closure of the switch takes place as the reverse of this operation. The contact parts 5 remain fixed during such normal circuit openings and closings.

In the event of a short circuit, however, such as in the phase of the contacts shown, for instance, the blower magnet 6 attracts its armature 3, which rotates rod i to free nose or projection 3, and the action of spring la carries contact 8 to the right, separating it from contact part 2. At the end of this movement of contact i the end portion lb of the contact engages lug 3i rotating pawl lever 25 in a clockwise direction, which has the effect of dropping shoulder 27 and freeing bail lever I5 from its engagement therewith at 28. The rotary movement of pawl lever 26 likewise causes nose 33 to open interference switch ii. The bail lever i5, freed of engagement with pawl lever 25, is moved in a clockwise direction by spring is to a position against stop 65, and the push button i2 is moved to the left outwardly from wall 36, having been approximately flush with the wall beforehand. The opening of interference switch H opens the circuit of the switch magnet 3 so that the armature 'i, with contact 2, falls away therefrom, and the abutment 2d at the same time releases depending arm 23 of pusher lever i9. The ball I 8 with levers i9 may now be rotated in a clockwise direction by spring 23 and faces 22 of levers H! are brought into contact from below with the ends of contacts i.

When it is desired to re-switch-in the mechanism the push-button i2 is depressed and the movement of bail lever H5 in a counter-clockwise direction engages the shoulder 2| of pusher lever HQ with the end of contact i. Continued movement of bail lever i5 restores contact i to it's original position with projection 33 engaged with rod l, armature 3 having in the meantime fallen away from magnet 5. With thecounter-clockwise retation of lever II, the abutment 23 thereof slides along the surface 41 of pawl lever 23 until it falls over shoulder 21 and is engaged thereby, the pawl lever 23 resumes its normal position through action of spring 28, nose 30 disengages switch ii. allowing it to close. The normal switching-in of the circuit breaker can now be effected by pivotal movement of armature l with contact 2. Abutment 24 then engages arm 23 and pusher lever i9 with shoulder 2! is taken out of contact with contact member 6.

In the event oi excessive temperature the bimetallic strip 33 moves in the direction of the arrow in Figure 1, moving key bolt 35 to the left, which rotates rod 34 so as to free the end of lever 33. The spring 43 is then abl to move

lever

39, 32 in a counter-clockwise direction, and the abutment 33 strikes pin M, which rotates pawl lever 23 to disengage ball lever i5, and the lever moves in a clockwise direction, movin push button iii to the left. The nose 3!] opens switch i i, to pivot contact l, as already described in the case of the short circuit release. When lever i5 oscillates into switching off position, its lever 28 engages abutment M and restores

lever

33, 32 to its original position with the end of lever 39 engaged against shaft 36, bimetallic strip 33 having returned to its original position.

In the embodiment of the invention described the position of the press button i2 visible from the outside of the switch casing indicates the condition of the switching mechanism. After a high speed operation brought about either by a short circuit or excess temperatures, the button projects a considerable distance from the casing, while with a normally closed circuit it is much closer to a flush position with the casing.

Referring now to the embodiment of the invention shown in Figure 2 of the drawings the parts numbered i to i3 and i5, i3, 25, 33, 33, 39, 35 are functionally identical to the similarly numbered parts in the embodiment of the invention shown in Figure 1, and their operation will be understood from the foregoing description.

In this embodiment of the invention (Figure 2) the push button i2 is connected by a toggle system with the bail lever i5. On the shaft iii of bail lever i5 there is freely rotatably mounted a swing arm or member 50 being spring pressed in a counter-clockwise direction by leaf spring 52 on lever i5 and having an abutment 5i to limit its angular motion with respect to lever 95. Arm 30 has a cross member 53 engageable by an abutment $3 on lever 55, and the cross member carries a pin 34 to engage the rear end of contact part i. Cross member 53 also carries a depending pin 55 adapted to engage an arm of the interference switch H. A spring 56 urges lever i5 in a clockwise direction against its stop 45.

The bimetallic strip 33 is apertured to receive a tie bolt 5'7 which is loosely arranged with respect thereto, and a head 58 on the tie bolt is adapted to engage member 33 when it moves in response to heat to the right, as indicated by the arrow. The tie bolt 51! is adjustably threadedly engaged at the upper end of a lever 58a which is adapted to turn rod 34, mounted for movement about its 1ongitudinal axis. Rod 34 is abutted by lever 39 and has a fiat end portion to permit escape of the lever when the rod is turned. Lever 58a is urged in a counter-clockwise direction against a stop 60 by a spring 59, and lever 39 is urged in a clockwise direction against rod 3&3 by a spring 69. Lever 33 is mounted for free rotation on shaft it,

and has an upper arm 48 to engage a pin 85 on the arm 50.

When the switch is closed. that is, when armature I is rotated in a clockwise direction from its position shown in Figure 2, the abutment 24 engages one of the toggle arms 48 and. keeps the toggle downwardly collapsed. One of the toggle arms 48 carries a pin 65 at its end for engagement with the lower end of lever I5, and the pin also serves as a guide member for the toggle by entering a slot 67 in a stationary portion of the device. When the toggle arms 48 are collapsed, as described above, the pin 56 is shifted to the left away from the end of lever I5. The lever I under the influence of spring 56 is rotated against stop 45, and spring 52 rotates arm 50 so that its abutment 5i engages lever I5, pin 55 being maintained clear of switch II.

On a normal switching-off operation when armature I is pivoted to its position shown in Figure 2, the stop 24 disengages its toggle arm 48, and the toggle straightens out under action of toggle spring 68. The pin 55 travels down slot 61 to its position shown in Figure 2, but does not engage lever I5, which is pivoted against its stop 45. When the armature I is again pivoted to switch in, toggle 48 is again collapsed by stop 24.

In the event of a short circuit, the contact part I is released by action of magnet 6 and armature 5, and in its motion to the right engages pin 54 toward the end of its movement and rotates swing arm 50 toward lever I5. Pin 55 opens switch II,

and swing arm 50 stops against abutment 49. The opening of switch II causes armature I with contact 2 to fall off, placing the members in open switch position. Toggle 48 then assumes its extended position. When the push button I2 is now depressed, pin 66 moves lever I5 in a counterclockwise direction and abutment 49 transfers the movement to arm 50, which, by pin 54, restores contact part I to its normal position, with projection 3 held by rod 4. Upon release of the push button I 2. spring 56 draws lever I5 back again against abutment 45, and arm 50 is drawn clear of contact part I by abutment 5i.

In the movement resulting from the depressicn of push button I2, interference switch II is cleared from pin on cross member 53 so that the subsequent normal switching-in brings armature I and contact 2 into closed position. With this movement stop 24 causes the toggle 48 to collapse, and the push button is then again inoperative upon lever I5.

In the event of overload the bimetallic strip 33 draws member 5'! in the direction of the arrow releasing arm 35 for pivotal action about axis I6 by spring BI. Arm 63 then engages pin 65 moving swing arm 55, opening interference switch II with pin 55. Armature I pivots and toggle 48 is allowed to assume extended position.

When the button I2 is now depressed to reswitch-in pin 56 pivots lever I5 to pivot arm 50 by abutment 49, and arm 39 is returned to lock position with respect to member 34 by means of pin 65, the member 34 having returned to its original position due to cooling of strip 33.

It will be apparent that in the embodiment of the invention just described, as in the case of the embodiment of Figure 1 of the drawings, the push button I2 is inoperative upon the mechanism until such time as there has been a high speed circuit breaking due to short circuit or excessive heating. By these mechanisms switching-off resulting from unintentional depressing of the buttons is prevented and service disturbances for such reasons are absolutely prohibited.

The invention in its broader aspects is not limited to the specific mechanisms shown and described but departures may be made therefrom within the scope of the accompanying claims without departing from the principles of the invention and without sacrificing its chief advantages.

We claim:

1. In an electric circuit breaker having a switch magnet and an interference switch in the circuit of the switch magnet, a moveable contact and a normally stationary contact latched in a normal position and biased to a tripped position when unlatched upon the occurrence of predetermined conditions, mechanism moved by movement of said normally stationary contact from normal to tripped position opening said interference switch in tripped position, means for returning said mechanism and said normally stationary contact to set position when said predetermined conditions are no longer present, said returning means being rendered inoperative upon said normally stationary contact by operative engagement with said moveable contact in switched-in position.

2. In an electric circuit breaker having a switch magnet and an interference switch in the circuit of the switch magnet, a moveable contact and a normally stationary contact latched in a normal and released to a tripped position upon short circuit, a lever moved by movement of said normally stationary contact from a normal to a tripped position engaging and openin said interference switch in tripped position, push button means interconnected with said lever for returning said normally stationary contact and said lever to set positions, said push button means being rendered inoperative upon said lever except in its tripped position by operative connection with said moveable contact in its switched-in position.

3. In an electric circuit breaker having a switch magnet and an interference switch in the circuit of the switch magnet, a moveable contact carried by the armature of said switch magnet and a normally stationary contact latched in a normal and released to a tripped position upon short circuit, a first lever moved by movement of said normally stationary contact from a set to a tripped position engaging and opening said interference switch in tripped position, a second lever for holding said first lever in set position having means for engaging said normally stationary contact to return it to a normal position, and abutment means between said armature and said engaging means preventing engagement of said engaging means with said normally stationary contact when said armature is in switch-closed position.

v 4. In an electric circuit breaker having a switch magnet and an interference switch in the circuit of the switch magnet, a moveable contact and a normally stationary contact latched in a normal and released to a tripped position upon short circuit, first lever means moved by movement of said normally stationary contact from a set to a tripped position engaging and opening said interference switch in tripped position, and a second lever having a set position to engage and hold said first lever in its set position and released position, said lever having means for engaging and returning said normally statio'nary contact from a tripped to a normal position.

5. In an electric circuit breaker having a switch magnet and an interference switch in the circuit of the switch magnet, temperature responsive means, a first lever moveable from a set to a tripped position to engage and open said interference switch in tripped position, a second lever to hold said first lever in set position and to return said first lever from tripped to set position, and a third lever actuated by said temperature responsive means to release said first lever from" said second lever allowing it to move to tripped position, said third lever being automatically returned by said second lever.

6. In an electric circuit breaker having a switch magnet and an interference switch in the circuit of the switch magnet, a moveable contact on the armature of said switch magnet and a normally stationary contact moveable upon short circuit from a normal latched to a released tripped position, means for opening said interference switch when said normally stationary contact moves to tripped position and means for returning said normally stationary contact to normal position, said last means including a toggle actuated returning lever and means on said armature for collapsing the toggle and rendering it inoperati e upon the returning lever when said contacts are closed.

7. In an electric circuit breaker having a switch magnet with an armature and an interference switch in the circuit of the switch magnet, temperature responsive means, mechanism actuated by said means to move from a set to a tripped position engaging and opening said interference switch in tripped position, and means for returning said mechanism to a set position including a toggle and means carried by said armature to engage and collapse said toggle rendering it in effective upon said mechanism when said armature is in attracted position with respect to said magnet.

8. In an electric circuit breaker having a switch magnet and an interference switch in the circult of the switch magnet, a moveable contact and a normally stationary contact latched in a normal position and biased toward a tripped position when unlatched upon the occurrence of predetermined conditions, mechanism actuated by movement of said normally stationary contact from a set to a tripped position opening said interference switch in tripped position, and means for returning said mechanism to set position when said predetermined conditions are no longer present, said returning means being operatively connected with said moveable contact to render said returning means inoperative upon said mechanism except when said moveable contact is in switched-out position.

KARL BOLLMANN. HANS MEIER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS