US1939132A - Circuit breaker - Google Patents

Description

E. D. MOORE CIRCUIT BREAKER Dec. 12, 1933.

2 Sheets- Sheet 1 Original Filed March 12. 1929 Hm. m n m. u I n w I 9 I A. w v u t R u w K n 7 m 5 A z: my M B u r v E a v z E kw 2 l WWW/I Dec. 12, 1933. E. D. MOORE 1,939,132

CIRCUIT BREAKER Original Filed March 12, 1929 2 Sheets-Sheet 2 W t I nverilor 'DGA/PD. M001? A tlomey PatentedDec. 12, 1933 UNITED STATES PATENT OFFICE" CIRCUIT BREAKER Edgar D. Moore, Mansfield, Ohio, assignor to The Ohio Brass Company, Mansfield, Ohio, a corporation of New Jersey Original application March 12, 1929, Serial No. 346,435. Divided and this application April 22, 1930. Serial No. 446,377

8 Claims. (01. zoo-s9) 5 which can be opened or closed manually or can value flowing for a predetermined time and in which the elements oi. time and current will vary inversely.

Other objects of my invention will appear as my invention is further disclosed. This application is a division 01' my co-pending application Serial Number 346,435 filed March 12th, 1929.

In the drawings:-

Fig. 1 is a top plan view ofmy switch in what I would term neutral" position, that is, it is open and cannot be closed by moving the handle to the closed position. A cover is shown almost entirely broken away.

Fig. 2 is a partial plan view of my switch as shown in Fig. 1 and which position I term the set position, that is, the operation of the switch handle in either direction will either open or close the switch. As shown in Fig. 2, the switch is in the open set position and the automatic overload mechanism iif operated will return the mech-' anism to the neutral position shown in Fig. 1.

Fig. 3 is a partial plan view of my switch shown in the closed set position.

Fig. 4 is a side view with the cover broken away.

Fig. 5 is a side view of Fig. l to show the thermal control mechanism.

Figs. 6 and 7 are plan and edge views respectively of the operating handle and lever.

Figs. 8 and 9 are plan and edge views of a floating bell crank and latch.

Figs. 10 and 11 are plan and edge views respectively of the switch lever.

Fig. 12 is a plan view of the support member for the switch mechanism.

Figs. 13, 14 and are schematic views of the switch mechanism only and correspond with the positions of the mechanism shown in Figs. 1, 2, and 3 respectively.

In the preferred embodiment of my invention I provide a base 1 preferably of insulating material. Mounted upon the base are terminals 2 and 3 to which are connected the translating device such as an electric motor, a bank of lights, etc. Terminals 4 and 5 have connected thereto the leads from the source of power.

Mounted upon the base 1 is an electro-magnetic trip mechanism M comprising a soft iron core 6,

pole pieces '7 and 8, a pivoted armature 9 with a latch 10 and energizing coils 11 and 12.

Mounted upon the base 1 is also thermal mechanism T comprising a hairpin shaped element 13 M composed of what is known as thermal metal comprising two dissimilar metals possessing different co-efilcients or expansion and which are welded together. The adjacent ends 14 and 15 oi the thermal. element are rigidly secured to the base but the closed end is free to move and has 'secured thereto a contact element 16 arranged to contact with an adjusting screw 17 mounted in a standard 18 and secured to the base by the screw 19.

The thermal element .13 is so positioned that if its temperature is increased above normal, its free end will bend upwardly until finally the contact 16 will engage with the screw 17. The fixed ends of the thermal element 13 are connected to the posts 2 and 4 by means of the conductors 20 and 21 and are secured to the base and'the conductors 20 and 21 by means of the screws 22 and 23.'

Mounted also upon the base is a switching mechanism S and comprising a support 24 secured to the base by means of the screws 25. Fixedly secured to the upper side of the support 24 by means of the screw 25 is a member 26 having -a projecting arm 26' and pivotally mounted upon the projecting arm 26 of the member 26 is the floating bell lever 2'7 by means of the pin 28 about which the lever 27 pivots. The members 24 and 26 may both be of metal, either integral or separately formed, or the member 24 may be formed up as an integral part of the base.

Pivotally mounted upon the lever 2'7 by means of the pin 29 is the switch lever 30 having a contact 31 which will engage the contact 32 when the switch is closed. The contact 32 is mounted upon the standard 33 secured to the base by means of the bolt and nut 5. The lever 27 is provided with a catch 34 which engages with the latch 10 when the switch S is in the set position.

The member 26 has an arm 26" projecting in the opposite direction from 26' and pivotally mounted thereon by the pin 35 is the operating lever 35 having an insulated handle 36.

The blade 30 and arm 35 have upstanding members 37 and 38 respectively and to which are secured the ends of the spring 39. The various parts composing the switch are so dimensioned and positioned that the operating lever 35 will contact with the arm 26 when it is moved to the right or closing position of the switch and is thus limited in its movement when the switch is in either its set or neutral positions. The blade 30 will engage with the upturned end 40 of the lever 27 and its movement to the right or closing direction will also be limited when the switch is in the neutral (Fig. 1) position, but is not limited when the switch is in the set position.

The switch parts shown in Figs. 6 to 11 inclusive and the parts 26 and 33 can very easily and cheaply be made from stamped sheet material.

It will be noted that as the operating lever 35 is moved to the right or left, that its lower end is switched to the right or left hand side of the longitudinal line through the blade 30, thereby placing spring tension upon the member 30 either to the right or left of the axis of the blade 30, which in turn will cause the blade 30 to be moved to the right or left in accordance with the movement of the handle to the right or left. This movement is accomplished with a snap action thereby producing what may be termed a quick make and break of the contacts 31 and 32. The floating lever 27 is provided with a portion 41 which contacts with the member 38 on the oper- 5 ating lever.

When the switch mechanism is in the neutral position, the elements and engage and the parts 38 and 41 will engage and the member 30 will engage with the upper end of the armature 30 9 or the end of the pole piece 8, and such contacting of parts is due to the spring tension and the floating feature of the lever 27 which permits the various parts described to move into contacting position.

When the switch lever shown in Fig. 1 is moved to the left, the member 38 moves the member 41, which in turn pivots the lever 27 about the pin 28, thus forcing the catch 34 upwardly until finally 'it engages with the latch 10 and the spring 42 will 40 hold the latch in co-operative relation with the catch 34 until released electro-magnetically. This brings the parts into the relation shown in Fig. 2 and the handle is maintained to the left or in the off position and the switch blade likewise.

If it is desired to close the switch, the handle 36 is moved to the right and after the pin 38 has passed beyond the longitudinal axis of the blade 30, the spring tension then acts to quickly move the blade 30 to the right and bring the contacts 31 and 32 into engagement, thus closing the switch and maintaining the switch handle to the right, all as shownin Fig. 3. In this position the handle will be against the arm 26. The handle 36 may now be moved to the left or right alternately as desired to open and close the switch respectively.

In Figs. 13, 14 and 15 I have shown three schematic drawings to indicate the relative position of the various levers in the "neutral, the open "set and the closed set positions. It will 0 be noted in Fig. 13 that while the handle may be moved in the closed direction and against the end of the stop 26', thereby putting the spring under tension on the right hand of the blade 30, the blade 30 will be moved in the closed direction until it engages the end of the stop 40. Therefore, in the neutral position the movement of the handle to the right will not close the switch.

When the coil 11 or 12 is sufliciently energized to attract the armature 9 and if the switch is in 7b the closed set position, then the lever 2'7 will be released from its position shown in Fig. 3 and it will immediately drop to the position shown in-Fig. 1 and the switch will be opened. This is due to the pin 38 being fixed at the time and 7 the spring drawing downwardly on the pin 37 which forms part of the blade, which in turn is secured to the lever 27. I

The member 27 is provided with an important element 27' arranged to engage the lever 35 as the member 27 rotates about 28 from the closed set position in Fig. 3 and forces the lever 35 to the left about 35' thus moving the spring axis through the points 37-38, to the left of the pivot 29, thus throwing the blade 30 to the full open neutral position. Without the element 27' the blade 30 would move to a partially open neutral position from a closed set position.

Also, if the parts are in the closed set position as per Figs. 3 and 15 and the operator is holding the handle to the closed position and if the armature should be drawn out of engagement with the lever 27, then the spring will act to draw the blade downwardly and pivot the lever 27 about the pin 28 and the stop 40 will be moved to the left, thereby moving the switch blade 30 out of engagement with the fixed contact 33. From this it will be seen that it will be impossible to manually hold the switch closed it the current therethrough exceeds a predetermined amount.

It will be noted that when the switch is closed and connected to a source of power and to a translating device, that current will flow from the source of power lead connected to the post 4, through the thermal element 13 to the post 2, then through the translating device to the post 3, through the lead 44, coil 11 and through the switch parts which are all metallic to the post 5 to which the other power lead is connected.

The contacts 16 and 1'7 are normally open but if the current flowing through the element 13 is sufllcient and flows for a sumcient length of time, the element 13 will gradually heat and as it heats the free end will move upwardly until the contacts 16 and 17 engage, then current will flow from the power lead connected to the post 4, through the lead 21 and through the thermal element 13, support 18, through the lead 43 and the coil 12 and coil 11 and thence through the switch mechanism to the contact 5, which is the other source of power. This will throw the coil 11 and coil 12 in series across the source of power and will energize the magnet 6 so that it will draw the armature 9 away from the catch 34 and release the switch mechanism, permitting the switch to open if closed. The coil 12 I prefer to have of a number of turns of fine wire. The higher the current through the thermal element 13, the shorter will be the time required for the element 13 to heat to close the contacts 16 and 17 and vice versa.

The coil 11 which is preferably of a few turns of larger wire, is constantly in series with the power and translating circuits and it energizes the core in relation to the current flowing to the translating device, but if this current should suddenly reach or exceed a predetermined amount, then the magnet 6 would be energized sufllciently to attract the armature 9 and release the lever 27, permitting the switch to open if closed.

It will be noted that the switch 8 cannot be closed unless it is in the set" position, that is, the

position in which it can be influenced by the coils 11 and 12 and it cannot be returned to its neutral position only when it is in the closed set position.

My invention is particularly adapted for protecting small motors such as are used in operating washing machines, electric refrigerators, etc.,

although it may be used for other purposes as, for

instance,themainlightingloadofahouse or other building.

A fuse does not protect tinuous excessive overload because the fuse must be of such capacity that it will safely'withstand the starting current of the motor for a reasonably sustained length of time, and therefore, it will not protect the motor for a sustained overload below that of the starting current. For instance, if a motor has a starting current of 10 amperes, the fuse must be of such capacity as to withstand this starting current. If the normal load current is 5 amperes with a capacity to withstand 50% overload for a short time or 7% amperes, then the fuse would not blow for 7% amperes and the motor would be damaged.

In my invention the energization of the coil 12 through the operation of the thermal element will cause the circuit to be opened after a predetermined time for a predetermined load, therefore giving a protection to the motor which cannot be secured with a fuse, and as the time lag of the thermal element can be varied it can be so ad- Justed that the circuit will not be opened when starting the motor, but should it be attempted to start the motor with an excessive or stalling load thereon, then the coil 12 would be suificiently and quickly energized through operation of the element 13 to cause the switch to'open.

Also the energization of coil 11 under a sudden and heavy load offers protection to the thermal element, which for small motors I find must be made quite delicate and unless the current thereihrough is caused to cease almost instantly in case of an excess current therethrough, the thermal element is very likely to take a permanent kink and be thrown out of adjustment and therefore it will not function.

Devices have been made in the past in which the fuse is used in circuit with the translatin device and the thermal element, which under a sustained current will operate to short circuit the fuse and blow the same, thus opening the circuit but no such devices are now on the market as they are deficient as the fuse possesses a time lag in operation and before the same will blow, the thermal element is likely to be damaged as previously explained, but by employing the proper electromagnetically controlled cutout operated by the excess current, I am able to not only protect the translating device from such excessive current, but also protect the thermal element as such electromagnetic device is very rapid in its operation.

A fuse cannot be adjusted for an overload and for a sustained load but my device can be so adjusted and the values are independent of each other.

I claim:

1. A switch comprising a fixed contact engaged by a contact on a pivotally mounted contact lever, an operating lever, the contact lever pivotally mounted between the center and end of a support which is pivotally mounted between its ends and the operating lever mounted on a fixed member, the pivot points of the levers being spaced apart and the longitudinal axes of the levers being in parallel alignment only when the pivotally mounted contact lever is in a position intermediate its open and closed positions, a spring connecting the levers and having its longitudinal axes in parallel alignment with the axes of the levers when in alignment and at other times biased to move the contact lever to its open or closed positions, eiectro-magnetic means coma motor against con-,

prising an armature pivoted at one end arranged to engage one end of the support to hold the pivotally mounted support from pivoting in one direction and to permit the contacts to move out of engagement to open the switch in response to predetermined current conditions and the other end of the support to engage the contact lever to prevent the closing of the contacts'when the armature has released the support.

2. A quick-break switch comprising a base member, a fixed contact mounted thereon, an

pivotal point of the support and one end thereof and a stop secured to the support between its pivotal point and the other end of the support to engage the contact arm to prevent the contacts engaging when the switch mechanism is in its non-set" position, a manually operable lever pivotally mountedto move relative to the support member and to the contact arm to move the support member to its set position and an over center spring connecting the contact arm and the manually/operable lever to move the contact arm to its open" or its closed position when the said lever-is operated and the support member is'in its set" position and to move the support member to its non-set" position and actu ate the movable contact out of engagement with the fixed contact when the switch mechanism is tripped, and a pivotally mounted current responsive holding member arranged to automatically engage the support member when the support member is moved to its se position and releasably hold the support member in its set" position.

3. A switch comprising in combination a base, a fixed contact thereon and a movable contact to engage therewith and mounted upon a pivotally mounted switch member, a non-bendable pivotally mounted latch for holding the switch member in its switch-closing position and electro-magnetlc means to trip the said latch to disengage the switch member, a spring biased to move the switch member and separate the contacts and means on the switch member to engage the movable contact when the switch member is released to prevent closing'the contacts.

4. A switch comprising a fixed contact, a supporting member having two diverging arms and.

pivotally mounted to a fixed support at the point of divergence of the arms, a movable contact to engage with said fixed contact and pivotally mounted on one of the arms of the supporting member, an operating member movable to either a switch-opening or closing position, a spring connected to the movable contact and operating members and biased to move the supporting member to the opened or closed position with respect to the fixed contact, means to change the positions of the supporting and movable contact members to a neutral or a set" position as described, means to stop the movement of the operating means in a switch-closing direction when the parts are in either a set or a neutral position, means on the supporting member to prevent the contacts engaging when the operating member is moved in a switch-closing direction and the parts are in a neutral" position, the spring means biased to move the contacts into or out of engagement whenever the operating means moves to the switch-closing or opening positions respectively, and the parts are in the "set position and biased to automatically hold the contacts out of engagement while the parts are in their neutral" position and electrically-controlled means provided with an armature latch to engage the arm on which the movable contact is mounted to releasably hold the supporting member in its se position.

5. A switch device comprising a fixed contact, a pivotally mounted support comprising two connected and diverging arms pivoted at the point of divergence and'havinga neutral" and a set position, a switch lever pivotally mounted on the support between its pivotal point and the free end of one arm and carrying a contact to engage the fixed contact to close a circuit through the switch, an operating lever pivotally mounted independently of the support and switch lever to manually control the opening and closing of the switch, an overcent er spring connecting the two levers and operating the switch lever to its open or closed position upon movement of the operating lever only when the support is in the set" position and biased to move the support from the set position to the neutral" position, nonbendable pivotally mounted means to releasably hold the support in the set position and an electro-magnetic device to act upon the holding means to release the support when the said device is energized.

6. A switch comprising a fixed contact, a movable support pivoted at its center and having an operative and an inoperative position, a contact bearing lever pivoted on the support away from the said support pivot, the lever movable by hand to move the contact bearing lever about its pivot to engage and disengage the contacts and move the support to its operative position, a latch to releasably engage one end of the support to hold the support in its operative position, electro-magnetic means operative to release the latch when the said means is energized and a spring connecting the levers to operate the contact bearing lever in response to movement of the hand movable lever and to move the support from its operative position to its inoperative position.

7. An electric switch comprising a fixed contact, a supporting member pivoted adjacent its center to a fixed support and having its ends unsupported, a contact bearing lever pivoted on the supporting member between the pivotal point oi the supporting member and one of its ends, a manually operable member to move the supporting member about its pivot point and simultaneously reciprocate the contact lever and to engage the aforesaid end with an armature latch to hold the supporting member in its latched position, electro-responsive means having an armature latch adapted to be released, resilient means connecting the contact lever and the manually operable member to move and hold the contact lever out of engagement with the fixed contact when the manually operable member is moved in one direction and to move the contact lever into and hold it in engagement with the fixed contact when moved in the other direction providing the supporting member is in its latched position, the said other unsupported end of the supporting member being engaged by the contact lever to prevent the contacts engaging.

8. An electric switch comprising a fixed contact, a movable contact to engage and disengage the fixed contact, a support pivoted adjacent its center and having its ends unsupported, the support having an operative and an inoperative position and to which positions the movable contact is pivoted to alternately close and open the switch when the support is in its operative position and to move the switch to its open position when the support is in its inoperative position, an overcenter spring biased to actuate the movable contact to its open position and the support to its inoperative position, electro-responsive means having an armature-latch to engage with one end 01' the support to hold the support in its operative position and the other end of the support to be engaged by the movable contact when the support is in its inoperative position to prevent the movable contact engaging the fixed contact.

EDGAR D. MOORE.

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