US2204528A - Circuit breaker - Google Patents

Description

J. H. BURNSIDE, 2D

CIRCUIT BREAKER June 11, 1940. v 2,204,528

Filed March 11, 1937 3 Sheets-Sheet 1 My .1 v 1 21 m a: 63 5.9 6%

INVENTOR. Jamesflflumwdgm 65 ATTORNEYS J n 1940- J. H. BURNSIDE. 2D

CIRCUIT BREAKER 5 Sheets-Shed 2 Filed March 11, 1937 Janiesliflurnszdqfi 111,5 ATTORNEYS June 11, 1940.

J. H. BURNSIDE, 2D 2,204,528

CIRCUIT BREAKER Filed March 11, 1957 5 Sheets-Sheet 3 Hi4 A-Hornys.

Patented June 11, 1940 UNITED STATES PATENT OFFICE CIRCUIT BREAKER York Application March 11,

19 Claims.

The present invention relates to circuit breakers and embodies, more specifically, an improved formv of a circuit breaker of the so-called plug type wherein the circuit breaker is adapted to be received within the standard form of receptacle now in use.

More particularly, the invention relates to the type of circuit breaker shown and described in applicant's co-pending application, Serial No. 104,895, filed October 9, 1936, for Circuit breaker, and this invention embodies certain important improvements by means of which the operation of breakers of this type is greatly facilitated.

An object of this invention is to provide a circuit breaker which is normally urged into an open position and held in closed position by an improved form of holding mechanism which is released by a bi-metal element, the holding mechanism being of such character as to cause it to hold the movable contact effectively in its closed position, at the same time permitting only a very slight pressure of the bi-metal element to release it from its holding position.

A further object of the invention is to provide an improved form of circuit breaker wherein the spring which urges the movable contact into an open position is effectively separated from the contact elements to prevent any injury to the spring by heat generated during operation.

A further object of the invention is to provide a circuit breaker of the above character having a spring to urge the same normally into an open position, the mechanism being of such character as to cause this spring to cushion the final opening motion of the movable breaker element.

A further object of the invention is to provide a circuit breaker of the above character wherein an eifective wiping contact is preserved between a central terminal of the breaker and the adjacent end of a movable contact-carrying spindle.

A further object of the invention is to provide an improved circuit breaker of the above character wherein a rotatable member is provided within the breaker for carrying the movable breaker contact and effectively inclosing certain of the breaker elements therein.

A further object of the invention is to provide a circuit breaker having an improved operating mechanism by means of which the movable breaker contact may be moved into a closed position, such mechanism preventing the movable contact from being held in a closed position under over-load conditions.

A further object of the invention is to provide an operatingmechanism for circuit breakers of 1937, Serial No. 130,262

the above character wherein the movable breaker contact is actuated thereby by motion of the operating means intermittently in a continuous direction.

Further objects of theinvention will be apparent as it is described in greater detail in connection with the accompanying drawings, wherem:

Figure 1 is a View in transverse section, taken on line |l of Figure 3, and looking in the direction of the arrows;

Figure 2 is a view in horizontal section, taken on line 2-2 of Figure 1, and looking in the direction of the arrows;

Figure 3 is a view in horizontal section, taken on line 33 of Figure 1, and looking in the direction of the arrows;

Figure4 is a view similar to Figure 3, showing the rotor in open position; V

Figure 5 is a View taken on the broken section line 55 of Figure 4;

Figure 6 is a plan view of the device in slightly reduced scale;

Figures 7, 8 and 9 are views in horizontal section taken on the line 4-4 of Figure 5 looking in the direction of the arrows, the said figures showing the mechanism in ofi, reset and on positions, respectively; 7

Figure 10 is a view in section showing the invention incorporated in an attachment plug.

Referring to the above drawings, a circuit breaker is shown as provided with a casing having a threaded portion 2i and formed with a partition 22. The threaded portion 2| is formed with a chamber 23 and receives a threaded shell 24, which is adapted to be threaded into a suitable socket or receptacle. A lower cover 25 is provided for the chamber 23 and carries a central terminal 26 to which a leaf spring 21 is secured. The leaf spring 21 is reversely bent and formed with a cup-shaped contact 28.

Within the partition 22 is received a spindle 29, the lower end of which is formed with a cap which is received within the cup-shaped wiper or contact 28. A coil spring 3| is secured at one end to the casing portion 2| and, at its other end, to the spindle 29, the function of this spring being to urge the spindle 29 normally into an open circuit position. In this connection, it is important to observe that the spring 3| is of such character as to expand against the cylindrical wall of chamber 23 when the spindle 29 approaches the final open circuit position, thus producing an efiective cushioning action upon spindle 29 at such time.

The interior of casing 28 receives a rotatable cylindrical member 32, which is secured to the top of spindle 29 to rotate therewith. A stationary contact 33 is provided in the inner portion of casing 20, this contact being carried by a currentccnduc 'ng member 34 having its lower portion 35 received within, and in electrical contact with, the shell 24. A graphite insert 36 is provided to prevent the destructive effect of arcing on the stationary contact 33.

The rotor 32 is formed with an inner chamber 31 and has secured thereto a cover plate 38 which encloses the mechanism within the chamber 31 to the-top of the spindle 29, which is received within the chamber 31, a conducting plate 39 is secured by means of a screw 40. This conducting plate 39 carries a bi-metal element 4|, the free end of which is formed with a curved pressure surface 42. A pigtail 43' connects the free end of the bi-metal element 4| with a movable contact 43 which is slidably received in the peripheral wall of the rotor 32. A spring 44 normally urges the contact 43 outwardly into the position shown in Figure 3, at which time the movable contact 43 engages the stationary contact 33. A graphite insert 45 is carried by the movable contact 43 to cooperate with the graphite insert 36 in preventing destructive arcing.

In order that the rotor may be held in a circuit-closing position, a detent 46 is slidably mounted therein and cooperates with a recess 41 in the wall of casing 20. This detent is moved axially by means of a toggle member 48, which is pivoted at 49 to the rotor 32. A spring 58 normally urges the toggle mechanism and detent into the position shown in Fig. 3, at which time the detent 46 engages the sloping surface 5| of recess 41 to prevent the opening of the circuit breaker. A shoulder 52 is provided by the recess 41 to engage the detent 46 and locate the mechanism in the closed position, as illustrated in Figure 3. It will thus be seen that an overload condition will cause the bi-metal element 4| to move outwardly and cause the pressure surface 42 to engage the toggle joint and release the same to permit the circuit breaker to open. Great accuracy results in view of the toggle mechanism by means of which a relatively slight force may be used to cause this opening motion, regardless of the friction or other conditions of wear between the detent 46 and the adjacent casing wall.

The movable contact 43 is provided with a pin 53 which is adapted to be engaged by -a latch 54 which is pivoted at 55 to the rotor 32. A spring 56 normally urges the latch into a pin-engaging position and the latch is formed with an upwardly extending arm 51 by means of which it may be released, as will be described hereinafter. The casing 28 is formed with a cam track 58 which serves to move the contact 43 inwardly into a latched position, as illustrated in Figure 4. The latch 54 holds the slide contact 43 securely in position so that when it slides past the recess 41 it will not engage the shoulder 52 thereof and thus make further rotation of the member 32 impossible.

Extending upwardly from the cover 38 is a central shaft 59, in the peripheral surface of which a groove 60 is formed, the groove being provided with a shoulder 6|.- cured to the shaft 59 and is provided with a head 63 upon which a pointer 64 is formed. Rotatably mounted upon the head 63 is a manually operable disc 65 which preferably is formed with its A pin 62 is se-' periphery lying contiguous to the periphery of the casing 28. Within the casing 28 a cover 66 is provided, the cover being formed with an upwardly projecting circular flange 61 having serrations 68 formed on its inner periphery. The manually operable member 65 is formed with a leaf spring 69 which is adapted to engage the serrations 68 and thus permit rotation of the member 65 in one direction only, (clockwise, as illustrated in Figure 8) Motion is transmitted between the member 65 and shaft 59 by means of a disc 18 which is pivoted at 1| to the under-side of the member 65. This disc is provided with a counter-clockwise bias by means of a spring 12 and is formed with an arm 13 which is adapted to engage the shoulder 6|. A second arm 14 is formed on the disc 10 and is pivotally connected to a toggle lever 15, the other end of which is pivoted at 16 to the lower side of the member 65. The central pivot 11 of the toggle member 15 extends downwardly and is adapted to engage a cam 18 having an inclined face 19 and a circular face 80. The cam 18 is formed upon the cover 66, as illustrated in Figure 5, and the toggle lever 15 is biased in the position shown in Figure 8 by means of a spring 8|. In this fashion, as illustrated in Figure 8, rotation of the member 65 causes arm 13 to transmit the motion of the member 65 to the shaft 59, thus turning the rotor 32. The cam 16 lies in the path of pin 11 to eifect a sequence of operations to be described hereinafter.

Also formed upon the member 65 and depending downwardly therefrom is a trip member 82 which is adapted to engage the arm 51 to release the latch 54 and brush 43 on the toggle lever 48 in order that the rotor 32 may be manually released.

Upon the member 65 is mounted a plate 84, being suitably secured to the member in such fashion as to prevent relative rotation with respect thereto. Plate 84 is provided with suitable indicia which have herein been indicated at 85, 86, 81 and 88.

In operation, and in the position illustrated in Figures '1 and 3, the circuit breaker is in its closed position, at which time pointer 64 points to indicia 86 (on). When excess current flows through the bi-metallic arm 4|, its pressure surface 42 moves the pin 83 on the toggle 48 outwardly, thus releasing the detent 46 and breaking the contacts 43 and 36. The tension in spring 3| causes the rotatable member 32- to rotate to the position shown in Figure 4, in which contact 43 is approximately 180 away from the position shown in Figure 3. During the rotation of the member 32, the contact 43 is moved inwardly by the cam surface 58 of the casing 28, until the latch 54 engages the pin 53.

To reset the circuit breaker, the member 65 is rotated in a clockwise direction. Such rotation of the member 65 causes the pin 11 to ride off the cam 18, at which time the toggle 15 assumes its normal position and the arm 13 engages shoulder 6|. Further rotation of the member 65 moves the rotor 32, eventually bringing the detent 46 into engagement with the recess 41, at which time the pointer 64 points to indicia 85 (reset). This last position is shown in Figure 9. The circuit, however, is still not closed since the latch 54 has not been released to allow the contact 43 to rest against contact 36. This operation is accomplished by further rotation of the member 65 so that the cam surface of the stop 82 will engage the arm 51, thus moving it radially outwardly and releasing the latch 54. At this point the pointer 64 points to indlcia 86 (on). The circuit breaker is now in the normal operating position and may be tripped by an overload, as described above.

The circuit may also be tripped manually by rotation of the member 65 beyond the on position. Such rotation causes the stop 82 to engage the pin 83 on the toggle 49, moving itoutwardly and thus releasing the detent 46 and breaking the circuit as described above.

In Figures 7, 8 and 9, the arrow found within the outline of the shaft 59 indicates the relative position of the movable contact 43. The arrow outside of the member 65 and at the bottom of the figures indicates the relative position of the stationary contact 33. From Figures 7, 8 and 9, it will be observed that the toggle and 8| and the plate 10 serve as the driving connection between the manually operable member 65 and the shaft 59. When the toggle 80 is in the position shown in Figures 7 and 8, the arm 13 on the plate 19 engages the adjacent shoulder on the shaft 59 forming the end of the cut-away portion 60. Turning the member 65 thus causes the shaft 59 to be turned and. such driving connection is maintained until the pin 11 at the mid point of the toggle 80 rides up on the cam 18 as illustrated in Figure 9. This results in breaking of the toggle and the aforesaid driving connection. The point at whichthis break occurs will be apparent from Figure 8 in which position the pin is just beginning to ride up on the surface of the cam. When the toggle is broken as illustrated 'at Figure 9, the manually operable member 65 has no driving or holding connection with the shaft 59 and the free tripping mechanism is thus unaffected by the member 65.

A further feature of the invention resides in the adaptation of a circuit breaker of the type above described for use in connection with an attachment cord. This is illustrated in Figure 10 wherein the prongs of an attachment plug 9|] are illustrated at 9| and 92. Prong 9| is formed with a central terminal 93 with which the contact 26 engages while the ,prong 92 is connected to one wire 94 of an attachment cord 95. The attachment cord may be carried by the plug by means of a threaded cap 96, the other wire 91 of the cord being soldered to the shell 24. A screw or other fastening element 98 may be provided to secure the casing 20 to the plug 90, recesses 99 and Hill being provided in order that the various elements may be countersunk within the plug and covered over by a suitable wax or other sealing element.

I claim:

1. A circuit breaker comprising a stationary and a rotatable contact, a rotatable spindle upon which the rotatable contact is secured, bi-metal controlled means to hold the rotatable contact in closed position, actuating means to move the rotatable contact into a circuit-closing position, a casing to enclose the contacts, a partition in the casing upon one side of which the contacts are disposed, said spindle being journalled in the partition, and a spring on the other side of the partition to urge the rotatable contact normally into an open position.

2. A circuit breaker comprising a stationary and a rotatable contact, a rotatable spindle upon which the rotatable contact is secured, bi-metal controlled means to hold the rotatable contact in closed position, actuating means to move the rotatable contact into a circuit-closing position, a

casing to enclose the contacts, a partition in the casing upon one side of which the contacts are disposed, said spindle being journalled in the partition, a spring on the other side of the partition to urge the rotatable contact normally into an open position, a terminal in the casing on the last-named side of the partition, and a wiping contact between the terminal and the adjacent end of the spindle.

3. In a circuit breaker, the combination of a fixed contact, a rotatable contact, manual means for moving the rotatable contact into closed circuit position, a spring normally urging the rotat' able contact into the open circuit position, bimetal controlled means for holding the rotatable contact releasably in the closed circuit position, a spring normally urging the rotatable contact into engagement with the fixed contact in the closed circuit position, latching means for holding the said rotatable contact releasably out of engagement with said fixed contact, and means for moving said rotatable contact into the latched position as the rotatable contact moves from the closed to the open circuit position.

4. A circuit breaker comprising a casing, a rotatable contact-carrying member in the casing, means to urge the member normally into an open position, means to move the member into a circuit closing position, a detent to hold the member in circuit-closing position, toggle mechanism to move the detent to a holding position, and means to engage the toggle mechanism to release the detent.

5. A circuit breaker comprising a casing, a rotatable control-carrying member in the casing, means to urge the member normally into an open position, means to move the member into a circuit-closing position, a detent on the member to hold the member in circuit-closing position, toggle mechanism to move the detent to a holding position, and means to engage the toggle mechanism to release the detent.

6. A circuit breaker comprising a casing, a rotatable contact-carrying member in the casing, means to urge the member normally into an open position, means to move themember into a circuit-closing position, a detent to hold the member in circuit-closing position, toggle mechanism to move the detent to a holding position, and bimetal means to engage the toggle mechanism to release the detent.

'7. A circuit breaker comprising a casing, a rotatable contact-carrying member in the casing, means to urge the member normally into an open position, means to move the member into a circuit-closing position, toggle mechanism to move the detent to a holding position, a shoulder on the casing to be engaged by the detent and stop the member in circuit-closing position, and means to engage the toggle mechanism to release the detent.

8. A circuit breaker comprising a casing, a rotatable contact-carrying member in the easing, means to urge the member normally into an open position, releasable means to hold the member in a circuit-closing position, a manually operable member, means movably mounted on the manual member to engage and move the rotatable member, and means to move the engaging means to prevent movement of the rotatable member thereby.

9. A circuit breaker comprising a casing, a. rotatable contact-carrying member in the easing, means to urge the member normally into an open position, releasable means to hold the mmber in a circuit-closing position, a manually operable member, a disc pivotally mounted on the manual member and having means thereon to engage the rotatable member, means to maintain the disc in engaging position, and means to render the last-named means ineffective to hold the disc in engaging position.

10. A circuit breaker comprising a casing, a rotatable contact-carrying member in the casing, means to urge the member normally into an open position, releasable means to hold the member in a circuit-closing position, a manually operable member, a disc pivotally mounted on the manual member and having means thereon to engage the rotatable member, toggle means to maintain the disc in engaging position, and means to render the last-named means ineffective to hold the disc in engaging position.

11. A circuit breaker comprising a casing, a rotatable contact-carrying member in the casing, means to urge the member normally into an open position, releasable means to hold the member in a circuit closing position, a manually operable member, a disc pivotally mounted on the manual member and having means thereon to engage the rotatable member, toggle means to maintain the disc in engaging position, and a cam to render the toggle means ineffective to hold the disc in engaging position.

12. A circuit breaker comprising a casing, a rotatable contact-carrying member in the casing, means to urge the member normally into an Open position, releasable means to hold the member in a circuit-closing position, a manually operable member, a disc 'pivotally mounted on the manual member and having means thereon to engage the rotatable member, toggle means to maintain the disc in engaging position, means to bias the toggle means and disc in an engaging position, and a cam to render the toggle means ineffective to hold the disc in engaging position.

13. A circuit breaker comprising a casing, a rotatable contact-carrying member in the casing, means to urge the member normally into an open position, releasable means to hold the member in a circuit-closing position, a manually operable member mounted coaxially of the said rotatable member, means mounted movably on the manual member to engage and move the rotatable member, and a trip member on the, manual member to engage the releasable means.

14. A circuit breaker comprising a casing, a rotatablecontact-carrying member in the casing, means to urge the member normally into anopen position, releasable means to hold the member in a circuit-closing position, a manually operable member mounted coaxially of the said rotatable member, means mounted movably on the manual member to engage and move the rotatable member, and a trip member on the manual member to engage the releasable means to hold the contact in an open position.

15. A circuit breaker comprising a casing, a rotatable contact-carrying member in the easing, means to urge the member normally into an open position, releasable means to hold the member in a circuit-closing position, a manually operable member means movably mounted on the manual member to engage and move the rotatable member, and means to permit motion of the manually operable member in one direction only.

16. A circuit breaker comprising a casing, a rotatable contact-carrying member in the casing means to urge the member normally into an open position, releasable means to hold the member in a circuit-closing position, a manually operable member means movably mounted on the manual member to engage and move the rotatable member indicating means on the manually operable member, and cooperating indicating means on the rotatable member for indicating the actual position of the contacts.

17. In a circuit breaker, a support having a fixed contact thereon, a rotor journaled on the support having a contact thereon, a spring con tinually urging the rotor to contact disengaging position when the contacts are engaged, a rotatable actuator for moving the rotor to contact engaging position, means mounted on the rotor and cooperating with the said support to hold the rotor in contact engaging position, and an excess current actuated element for releasing the said last mentioned means whereby the spring moves the rotor to contact disengaging position.

18. In a circuit breaker, a support having a fixed contact thereon, a rotor journaled on the support having a contact thereon, a spring continually urging the rotor to contact disengaging position when the contacts are engaged, a rotatable actuator for moving the rotor to contact engaging position, latching means for holding the rotor in contact engaging position, and an excess current actuated element carried by said rotor for releasing the said latching means, whereby the spring moves the rotor to contact disengaging position.

19. In a circuit breaker a support having a fixed contact thereon, a rotor journaled on said support having a contact thereon, a spring continually urging the rotor to contact disengaging position when the contacts are engaged, a rotatable actuator for moving the rotor to contact engaging position, means mounted on the rotor and cooperating with said support to hold the rotor in contact engaging position, and an excess current actuated element carried by said rotor for releasing said last mentioned means whereby said spring moves said rotor in contact disengaging position.

JAMES H. BURNSIDE, 2ND.

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