US1879714A

US1879714A - Switching mechanism

Info

Publication number: US1879714A
Application number: US591314A
Authority: US
Inventors: Jr William M Scott
Original assignee: ITE Circuit Breaker Co
Current assignee: ITE Circuit Breaker Co
Priority date: 1932-02-06
Filing date: 1932-02-06
Publication date: 1932-09-27
Anticipated expiration: 1949-09-27

Description

w. M. SCOTT, JR 1,879,714

SWITCHING MECHANI SM Sept. 27, 1932.

Filed Feb. 6, 1952 2 Sheets-Sheet l I u v n11 uv INVENTOR.

BY Wig AATTORNEY.

Sept. 27, 1932. w T, JR 1,879,714

SWITCHING MECHANISM Filed Feb. 6, 1932 2 Sheets-Sheet 2 75; ATTORNEY.

Patented Sept. 27, 1932 UNITED STATES WILLIAM M.

CUIT BREAKER OF NEW JERSEY soon, as, or rnrnanatrnm,

COMPANY, or rmmmnnrnm, PENNSYLVANIA,

ASSIGNQR TO I-T-E CIR- A CORPORATION PENNSYLVANIA,

SWITCHING MECHANISM Application fled February 8, 1982. Serial No. 691,814.

My invention relates to switching mechanisms, and articularly to circuit breakers having auxiliary switchin means actuated thereby and in a predetermined time relation 6 therewith.

In accordance with my invention, an aux liary switch, as a switch for connecting a discharge resistance to the circuit controlled by the circuit breaker at the moment of open- 1' ing the breaker, and having the proper operating and timing characteristics, is adapted to be connected to the standard type of circuit breaker, and has the further a vantages of greater reliability, increased speed, simplicity of structure, and economy of manufacture; specifically, the discharge switch structure comprises a driving arm, or equivalent, secured to the operating mechanism, for example, the operating arm, of the main switch of a circuit breaker and rotated thereby, the driving arm having studs which engage an opening of special contour in a link member connected to the blade of the discharge switch to actuate the same.

The timing of the switches, in the embodiment illustrated, is such that with the circuit breaker in closed position, for a given initial movement of the operating mechanism, the blade of the discharge switch has a large travel so that it engages its complementary fixed contact before the contact resistance of the arcing contacts of the main switch has substantially increased, and during the remainder of the movement of the operating mechanism the main switch contacts have a large travel to open position, while the blade of the discharge switch has a relatively small travel to reach its final position; with the circuit breaker in open position, for a given initial movement of the operating mechanism, the blade of the discharge switch has a large travel so that it is disengaged from its complementary fixed contact before the main switch arcing contacts engage, and during the remainder of the movement of the operating mechanism the main switch contacts complete their closing action while the blade of the discharge switch has a small travel to reach a final open position.

My invention resides in the features of construction, combination and arrangement hereinafter described and claimed.

For a better understanding of the invention, and for illustration of one of the forms it may take, reference is had to the accompanying drawings, in which:

Fig. 1 shows a type of circuit to which the invention is particularly applicable;

Fig. 2 is a side elevational view of a circuit breaker embodying the features of the invention;

Figs. 3, 4 and 5 illustrate various positions of the main and discharge switches during the opening movement of the circuit breaker of Fig. 1;

Fi 6 illustrates one position of the switc es during the closing movement of the circuit breaker; and

Fi s. 7 to 12 show details of the discharge swi blade and operating parts.

Various electrical circuits have highly inductive characteristics which produce an opposition to current fiow at the moment they are connected to a source of power, and tend to maintain current flow at the instant of 7 disconnection from the source of power. This latter condition is especially pronounced in direct current circuits, and causes a voltage rise at the circuit terminals which may cause severe arcing and may even rise above the 90 safe voltage of the c1rcuit insulation. To prevent this potential increase reaching clangerous values, it has been the practice to employ a special switch to connect the circuit terminals to the ends of a resistance circuit so that the inductive discharge flows through this auxiliary circuit and the abrupt voltage rise is prevented. This reduces arcing at the terminals and eliminates the necessity of I uslng special insulaton for taking care of the maxlmum instantaneous voltage.

The relative time of making and breaking the contacts of the main switch and discharge switch should be fixed so that, during the opening of the main switch, the contact resistance never exceeds that of the special resistance circuit. In other words, the discharge switch must make contact before the main switch breaks, but preferably in as short a a time before as possible, because the resist- 10 ance circuit is connected across the power line during the overlap. For this reason it is essential that during the.closing of the main switch the discharge contacts should be disconnected before the main contacts engage. Fig. 1 shows a circuit with an inductive load, as the motor M, and with the discharge switch 20 in a position of engagement to connect the discharge resistance R in circuit before the resistance of the arcing contacts 5 and 6 is appreciably increased.

Referring now particularly to Fig. 2 of the drawings, there is shown'a switch panel 1 of slate Or other suitable insulating material, having fixed

contacts

2 and 3 extending through the anel, and adapted to be bridged by the mova le contact bridge 4, carried by an arm 7 pivoted at 8 to the bracket member 9 secured to and extending from the panel 1. The upper fixed contact 2 of the main switch is provided with a pivoted arcing contact 5, of carbon, or the like, adapted to engage the movable arcing contact of similar material 6 mounted upon the end of the spring arm 31 securedbetween the contact bridge 4 and its supporting arm 7. The supportlng arm is connected at 10 to a link 11, which link is pivotally connected by a toggle pin 12 to the operating arm or lever 13 which rotates about a rod or pin 14 in the bracket 9. The handle 15 is attached to the operating arm 13 for manual operation of the circuit breaker.

In the position shown in Fig. 2, the toggle pin 12 is below a straight line intersecting the,

pins 10 and 14 so that the outward force of the contact springs tends to rotate the operating arm 13 in a counter clockwise direction. This action is prevented by the hook latch 16. The clockwise movement of this latch releases the operating arm and permits the breaker to open under the influence of springs. This latch may be disconnected by hand or by an electrical tripping device.

The discharge switch is mounted on one side of the anel 1, and adjacent the main switch, and 1s 0 erated from an attachment or driving memher 23 fixedly secured, as by screws, to the operating arm 13. The discharge switch consists of a contact terminal 17, and a hinge terminal 18 to which is pivoted at 19 a switch blade 20. An extension of this blade has riveted to it a stud 21 which carries one end of the operating link 22, preferably, although not necessarily, composed of insulating material. The switch driving arm 23 is also co-pivotally mounted on pin 14 with the operating arm 13, and controls the position of the operating link 22.

For a better understanding of the action of the discharge switch, Figs. 3, 4, 5 and 6 show the discharge switch mechanism and the relative ositions' of the main circuit breaker and discharge switch contacts. The actuating structure for the main contacts is omitted arm carries two cam mem ers, as the studs or

crank pins

24 and 25, which extend horizontally into the apcrtured portion or irregularly sha ed'opening 26 in the operating link 22. he pin 14 also extends through an apertured portion or rectangular opening 27 in the link 22. At a convenient point 28 of the link, a biasing spring 29 is attached drawing the link downward by its attachment at 30 to the bracket 9, not shown. I

Fi 3 shows the main contacts of the circuit reaker closed, and the discharge switch open. When the breaker starts to open, the arm 23 is rotated counter-clockwise by the operating arm, and therefore the stud or crank pin 24 moves counter-clockwise and, as the notch 26 in the link opening 26 partly embraces the stud, the link 22 is forced to the left. This action moves the switch blade 20 into engagement with its contact 17. During this motion the stud 25 has been rotating with stud 24, but due to its relative position it has been rising while the stud 24 has been descending. This causes the stud 25 to come in contact with the upper surface of the opening 26, as shown in Fig. 4, and lift the notch clear of the stud 24, this action also extending spring 29. The horizontal motion of the link 22 is stopped shortly after this by the side of the slot 27 striking the pin 14. Further opening of the breaker has little effect upon the position of theswitch, but the studs continue to rotate to theposition shown in Fig. 5 where the stud 25 is shown as engaging the notch 26, while stud 24 is at the left side of the opening 26.

It is seen that the switch blade 20 is given its full motion during the early part of the circuit breaker opening movement, shown by Figs. 3 and 4, and that during the final breaker opening movement the switch is substantially stationary.

The contact of the discharge switch blade 20 with its contact terminal 17 is timed to make just before the contact resistance of the circuit breaker secondary contacts 5 and 6 increases due to their opening movement, as shown in Fig. 4. This prevents the introduction of excessive resistance into the circuit and the consequent dangerous voltage rise. Thus, for a given initial movement of the circuit breaker operating mechanism towards open position, the discharge switch blade has a large travel so that it engages its fixed contact 17 before the contact resistance of the arcing contacts 5 and 6 of the main switch has substantially increased, and during the remainder of the movement of the circuit breaker mechanism, the main switch contacts 4 and 6 have a large travel to open position, while the blade 20 of the discharge switch has a relatively small travel to reach its final closed position.-

The action of the discharge switch during the closing of the breaker is timed so that the stud 25 pulls the discharge switch open before the secondary contacts 5 and 6 engage, as shown in Fig. 6. The final closing action of the breaker has little effect on the discharge switch position. Therefore, for a given initial movement of the operating mechanism of the circuit breaker towards its closed position, the blade 20 of the discharge switch has a large travel so that it is disengaged from its fixed contact 17 while the main switch contacts 4 and 6 have a small travel, and during the remainder of the movement of the circuit breaker, the main switch contacts have a large travel to reach closed position, while the blade 20 of the discharge switch has a small travel to reach its full open position.

Figs. 7 and 8 show the details in side and end elevational views of the operating link 22;

Figs. 9 and 10 similarly show details of the driving arm 23;.and

Figs. 11 and 12 show charge switch blade.

It will be seen that only two members, viz., the driving arm 23 and the link 22, are'essential to actuate the auxiliary switch and give it the proper operating and timing characteristics, and that these members may be used with the standard type of circuit breaker without modifying the circuit breaker structure, andmay be connected to existing installations, is, furthermore, applicable to auxiliary switches for other purposes than to control discharge resistances, for example, to control signalling and interlocking devices, since different operating and timing characteristics may be readily obtained by changing the contour of the apertures or the camming surfaces in the link 22 and/ or the arrangement of the

studs

24 and 25 on arm 23. By suitably shaping the apertures or the camming surfaces of link 22, the link may be used with a driving member having rectilinear movement instead of rotary or arcuate motion, and the driving member 23 may be connected to various parts of the circuit breaker operating mechanism other than the operating arm,and still retain the features and advantages of the invention.

What I claim is:

1. In combination with a circuit breaker, an auxiliary switch, and means for actuating the auxiliary switch in accordancewith movement of the main switch, comprising a mem her having a plurality of apertures and means connected to the operating mechanism of the details of the disif desired. The arrangement main switch and engaging the apertured portions of said member.

2. In combination with a circuit breaker, an auxiliary switch, and means for actuating the auxiliary switch in accordance with movement of the main switch, comprising a link member having a plurality of apertures and means connectedto the operating arm of the main switch and engaging the apertured portions of said link member.

3. In combination with a circuit breaker, an auxiliary switch, and means for actuatin the auxiliary switch in accordance Wltfi movement of the main switch, comprising a driving member connected to the operating mechanism of the main switch, and a member connected to the movable contact element of the auxiliary switch and actuated by said driving member, one of said members having camming surfaces and the other having camming means engaging the camming surfaces.

4. In combination with a circuit breaker, an auxiliary switch, and means for actuating the auxiliary switch in accordance with movement of the main switch, comprising a driving member actuated by the operating mechanism of the main switch, a link member for controlling the position of the auxiliary switch and having an apertured portion, and a plurality of means on said driving member for engagingsaid apertured portion to control the position of said link member.

5. In combination with a circuit breaker, an auxiliary switch, and means for actuating the auxiliary switch in accordance with movement of the main switch, comprising a driving member actuated by the operating mechanism of the main switch, a link member for controlling the osition of the auxiliary switch and having camming surfaces, and a cam on said driving member for engaging said camming surfaces to actuate the link member.

6. In combination with a circuit breaker, an auxiliary switch, and means for actuating the auxiliary switch in accordance with movement of the main switch, comprising a driving member secured to the to gle mechanism of the main switch, a 1m member for controlling the position of the auxiliary switch and having camming surfaces at one end, and a stud on said driving member for engaging said camming surfaces to actuate the link member.

7. In combination with a circuit breaker, an auxiliary switch, and means for actuating the auxiliary switch in predetermined time relation with respect to movement of the main switch contacts, comprising an operating arm connected to the toggle mechanism of the main switch and adapted to rotate therewith, means comprising a link for controlling the position of the blade of the auxiliary switch, the link having an apertured portion and the operating arm having crank 45 the auxiliary switc an apertured ing crank pins for engaging the apertured portion to actuate said link.

8. In combination with a circuit breaker, an auxiliary switch, and means for actuating the auxiliary switch in predetermined time relation with respect to movement of the main switch contacts, comprising a driving lever connected to the operating arm of the main switch, and adapted to rotate therewith, a

1 link pivotally connected to the blade of the auxiliary switch and having an a ertured ortion with camming surfaces an means or engaging said camming surfaces for controlling the osition of said link.

9. In com ination with a circuit breaker, an auxiliary switch, and means for actuating the auxiliary switch in predetermined time relation with respect to'movement of the main switch contacts, comprising a bell-crank lever fixedly connected to the operating arm of the main switch and adapted to rotate therewith, a link pivotally connected to the blade of the auxiliary switch and having an apertured portion, the bell-crank lever havins for engaging the apertured ortion and controlling the position of said ink.

v 10. In combination with a circuit breaker, an auxiliary switch, and means for actuating the auxiliary switch in predetermined time relation with respect to movement of the main switch contacts, comprising a bell-crank lever fixedly connected to the operating arm of the main switch and co-pivotally mounted therewith, a link pivotally connected at one end to the blade of the auxiliary switch and having an apertured portion at another end, the bell crank lever having crank Plus. for engaging the apertured portion, the contour 40 of the aperture and the movement of the crank pins controlling the position of the auxiliary switch blade.

11. In combination with a circuit breaker, an auxiliary switch and means for actuating h in predetermined time relation with respect to movement of the main switch contacts, comprising a bell-crank lever fixedly. secured to the operating arm of the main switch and co-pivotally mounted therewith on a supporting pin, a link pivotally connected at one end to the blade of the auxiliary switch and having two apertured portions at its other end, the bell-crank lever having crank pins for engaging one of the apertured portions, and said supporting pin extending through the other apertured portion of the link, the contours of-the apertures and said crank pins and supporting pin controlling the position and limiting the travel of the link and auxiliary switch blade.

- 12. Circuit breaker structure comprising a main switch and an auxiliary switch, a link connected to the auxiliary switch and having portion, crank pinsactuated by the toggle mechanism of the main switch for engaging said apertured portion, the contour of the apertured portion coacting with the movement of the crank pins to actuate the auxiliary switch.

13. Circuit breaker structure com risin a main switch and an auxiliary switc a link connected to the auxiliary switch and having an apertured portion, crank pins actuated by the toggle mechanism of the main switch for engaging said apertured portion, the contour of the apertured portion coacting with the movement of the crank pins to actuate the auxiliary switch and cause it to close before the main switch opens, and to open before the main switch closes.

14. Circuit breaker structure comprisin a mainswitch having arcing contacts am? a discharge resistance controlling switch, a link pivotally connected to the discharge switch and having an apertured ortion, crank pins actuated by the toggle meciianism of the main switch for engaging said a ertured portion, the contour of the apertured portion coacting with the movement of the crank pins to actuate said discharge switch and cause it to close before the contact resistance of said arcing contacts substantially increases during opening movement of the circuit breaker, and to cause the discharge switch to open before the arcing contacts engage during closing movement of the circuit breaker.

15'. Switching mechanism comprising an operating mem r, a plurality of crank pins actuated by said member, a link for actuating amovable switch member. and having a recessed portion, the crank pins successively engaging said recessed portion upon movement of the operating member to control the position of the movable switch member.

16. Switching mechanism comprising an operating arm carrying a plurality of crank pins and rotatably mounted, a link for actuating a movable switch element and having an apertured portion, and a recess in the apertured portion, the crank pins successively engaging said apertured portion and said recess upon movement of the operating arm to control the position of the switch element.

17. Switching mechanism comprising an operating arm carrying a plurality of crank plns and rotatably mounted on a pin, a link for actuating a movable switch element and having'an apertured portion, and a recess in the apertured portion, the crank pins successively engaging said apertured portion and said recess upon movement of the operating arm to control the position of the switch element, the link also having an apertured ortion for engaging said mounting pin to limit the travel of the movable switch element.

18. In combination with an air circuit breaker, a switch for an auxiliary circuit, a link actuated by two crank pins rotating with a member of the circuit breaker operating mechanism for operating said 4 auxiliary switch, a spring for biasing the link to a given position, said crank pins passing through an opening in said link, the contour of said opening being such as to operate in conjunction with the link spring and crank pins to control said auxiliary switch and cause it to make contact before the circuit breaker disengages contacts during its opening movement, and to open before the breaker engages contacts during closure.

19. In combination, a supporting panel, a switch mounted thereon, an operating link therefor, a bracket mounted on said panel and having a pin parallel to said panel, the pin pivotally supporting a member with limited rotary motion, two crank pins attached to said rotatable member alternately engaging a notch in said operating link to engage said switch during initial rotary movement in one direction and maintain said switch in substantially one position during the remainder of said rotary movement, and to disengage said switch during initial rotary movement in the opposite direction and maintain said switch in substantially one position during remainder of said rotary movement.

' WILLIAM M. SCOTT, JR.