Information
-
Patent Grant
-
6262642
-
Patent Number
6,262,642
-
Date Filed
Thursday, December 30, 199924 years ago
-
Date Issued
Tuesday, July 17, 200122 years ago
-
Inventors
-
Original Assignees
-
Examiners
Agents
- Cantor Colburn LLP
- Horton; Carl B.
-
CPC
-
US Classifications
Field of Search
US
- 335 16
- 335 147
- 335 195
- 218 22
- 218 32
- 200 244
- 200 250
-
International Classifications
- H01H7500
- H01H7700
- H01H8300
-
Abstract
A rotary contact arrangement for circuit breakers of the type including a pair of contact springs arranged on each side of a rotary contact arm, as the contact springs interconnect between the rotors and the contact arm via a pair of U-shaped levers. The provision of the U-shaped levers provides uniform contact pressure between both pairs of fixed and moveable contacts to prevent contact erosion.
Description
BACKGROUND OF INVENTION
This invention relates to circuit breaker, and, more particularly, to a circuit breaker rotary contact arm arrangement.
Circuit breakers having a current interrupting module within a rotary contact arm arrangement whereby the circuit breaker movable contact arms are arranged at the opposite ends of the movable contact carrier are able to interrupt circuit current at a faster rate than circuit breakers having a movable contact carrier with a contact arranged at one end. U.S. Pat. No. 5,310,971 entitled Rotary Contact System for Circuit Breakers, describes a rotary contact arm that employs rollers between the contact springs and the contact arm to provide a uniform force distribution between the fixed contacts attached to the circuit breaker line and load straps and the movable contacts arranged at the opposite ends of the movable contact arm. One problem associated with a non-uniform force distribution between the fixed and movable contacts is the possibility of excessive contact erosion on the pair of contacts at the lower force points along the fixed contact surface.
U.S. patent application Ser. No. 09/384,908 filed Aug. 27, 1999 entitled Rotary Contact Assembly For High Ampere-Rated Circuit Breakers describes connecting the circuit breaker contact springs with the movable contact arm by means of pivotally-arranged links to compensate for contact wear and erosion over long periods of extensive circuit interruption.
SUMMARY OF THE INVENTION
In an exemplary embodiment of the invention, a rotary contact arrangement for circuit breakers of the type including a pair of contact springs arranged on each side of the rotary contact arm, has the contact springs interconnected between the rotors and the contact arm via a pair of U-shaped levers. The U-shaped lever sidearms interact with the perimeter surfaces of the rotors whereas the bights of the U-shaped levers interact with the shaped surfaces of the contact arm to insure uniform spring force between the fixed and movable contacts.
Uniform contact pressure between both pairs of fixed and movable contacts in a rotary type circuit breaker is provided without having to interpose rollers between the contact springs and the movable contact arm, especially when used in multi-pole circuit breakers that require a separate movable contact arm in each of the separate poles
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1
is a front perspective view of a rotary contact circuit breaker interior employing the rotary contact assembly according to one embodiment of the invention;
FIG. 2
is an enlarged front perspective view of the rotor assembly contained within the circuit breaker interior of
FIG. 1
; and
FIG. 3
is an enlarged front perspective view of the rotor assembly contained within the circuit breaker interior of
FIG. 2
with the rotor plate removed to depict the U-shaped levers in greater detail.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to
FIG. 1
, a rotor assembly
20
in a circuit breaker interior assembly is generally shown intermediate a line strap
11
and a load strap
12
and associated arc chutes
16
A,
16
B. Although a single rotor assembly is shown, it is to be understood that a seperate rotor assembly is employed within each pole of a multi-pole circuit breaker and that each operates in a similar manner. The arc chutes
16
A,
16
B are similar to that described in U.S. Pat. No. 4,375,021 entitled Rapid Electric Arc Extinguishing Assembly in Circuit Breaking Devices Such as Electric Circuit Breakers, which is incorporated by reference. Electrical transport through the circuit breaker interior proceeds from the line strap
11
to an associated fixed contact
13
B to a movable contact
14
B connected to one end of a movable contact arm
15
. The current transfers then to the opposite end of movable and fixed contacts
14
A,
13
A to the associated load strap
12
. The movable contact arm
15
moves a pivot
18
(pin) in unison with a rotor
17
upon articulation of the circuit breaker operating mechanism (not shown) by links
19
A,
19
B to move the movable contacts
14
A,
14
B between, CLOSED and OPEN positions. The rotor
17
responds to the rotational movement of the pivot
18
to effect the contact closing and opening function. An extended pin
25
provides attachment of the rotor
17
with the circuit breaker operating mechanism through links
19
A,
19
B to allow manual intervention for opening and closing the circuit breaker contacts in the manner described within the aforementioned U.S. patent application Ser. No. 09/384,908 filed Aug. 27, 2000.
Referring to
FIG. 2
, a rotor assembly
20
a first embodiment of the invention is generally shown as a single unitary assembly comprising a pair of opposing rotor plates
17
A,
17
B joined by a pair of extended cylinders
21
A,
21
B each having a passageway as shown at
22
. The rotor plates and cylinders are preferably fabricated from a glass-filled thermoset resin having good structural and electrical insulative properties and the central operating pivot
18
extends through both of the rotor plates as well as the movable contact arm
15
. The rotor plates
17
A,
17
B each include, on their opposing perimeters, a U-shaped retainer slot
28
and a sloping carrier slot
29
which includes a raised radial stop as shown at
30
. An opposing pair of contact springs
23
A,
23
B are guided along shaped carrier slots
29
at one end by spring pins
26
A, to which one end of the springs is attached and are retained at an opposite end by means of spring pins
27
B that are captured within U-shaped retainer slots
28
. An opposing pair of contact springs
24
A,
24
B are guided along shaped carrier slots
29
at one end by spring pins
26
B to which one end of the springs is attached and are retained at an opposite end by spring pins
27
A that are captured within U-shaped retainer slots
28
. The spring pins
26
A,
26
B and
27
A,
27
B cooperate with a pair of U-shaped levers
31
A,
31
B in the manner best seen by now referring to the rotor assembly
20
shown in
FIG. 3
with the rotor plate
17
A removed and the cylinders
21
A,
21
B sectioned to depict the U-shaped levers
31
A,
31
B in greater detail.
Referring now to
FIG. 3
, the U-shaped levers
31
A,
31
B connect with the central pivot
18
through apertures
41
,
42
and each define a pair of opposing sidearms
32
A,
32
B and
34
A,
34
B joined by bights
33
,
35
respectively. The spring pins
26
A,
27
A at the ends of the contact springs
23
A,
23
B extend through openings
36
at the ends of the sidearms
32
A,
32
B and terminate on the surface of the carrier slot
29
, as indicated at
39
. The bight
33
joining the sidearms
32
A,
32
B rides along the surface
1
SB of one end of the movable contact arm
15
. The bight
35
joining the sidearms
34
A,
34
B rides along the surface
15
A of the opposite end of the movable contact arm. It is to be understood that the spring pins
26
B,
27
B are arranged in as similar manner on the rotor plate
17
A, shown earlier in FIG.
2
.
The provision of the U-shaped levers
31
A,
31
B intermediate the rotor plates
17
A,
17
B and the surfaces
15
A,
15
B on the opposing ends of the movable contact arm
15
thereby allows the forces of the contact springs
23
A,
23
B and
24
A,
24
B to interact in feed-back relation, whereby a generally constant force is applied between the fixed and movable contacts
13
A,
14
A and
13
B,
14
B of FIG.
1
. The forces exhibited by the contact springs at one end of the movable contact arm are transmitted via interaction with the bight associated with the one end to the bight associated with the other end of the movable contact arm to adjust the position of the bight associated with the other end thereof. An increase in force between one pair of fixed and movable contacts at one end of the movable contact arms is accordingly reflected in a corresponding increase in force between the other pair of fixed and movable contacts resulting in a constant force between both pair of fixed and movable contacts through-out the operational life of the associated circuit breaker
Claims
- 1. A circuit breaker rotary contact arrangement comprising:a pair of opposing circular rotor plates, each of said rotor plates defining a carrier slot on a perimeter thereof; a movable contact arm intermediate said rotor plates, said contact arm defining a first movable contact at one end arranged opposite an opposing first fixed contact and a second movable contact at an end opposite said one end arranged proximate a second fixed contact; a pivot pin extending through said rotor plates and said movable contact arm, whereby said rotor plates and said movable contact arm rotate in unison; a pair of first contact springs, one of said first contact springs arranged on one side of said movable contact arm and another of said first contact springs arranged on an opposite side thereof; and a U-shaped lever intermediate said rotor plates, said U-shaped lever defining a pair of sidearms joined at one end by a bight, said bight arranged proximate a first shaped surface formed on said contact arm for providing a constant spring force between said first and second fixed and movable contacts.
- 2. The rotary contact arrangement of claim 1 including a spring retainer pin arranged through one end of each of said contact springs and through said sidearms, at an end of said sidearms opposite said bight, said retainer pin defining a pair of opposing retainer pin ends, said retainer pin ends being positioned within said rotor carrier slots.
- 3. The rotary contact arrangement of claim 2 wherein said rotor plates further define a retainer slot on said perimeter thereof and said contact springs include an additional spring retainer pin arranged through another end thereof, said additional spring retainer pin being arranged within said retainer slot.
- 4. The rotary contact arrangement of claim 2 including an additional U-shaped lever intermediate said rotor plates, said additional U-shaped lever defining a pair of additional sidearms joined at one end by an additional bight, said additional bight arranged proximate a second shaped surface formed on said contact arm.
- 5. The rotary contact arrangement of claim 4 including a pair of additional contact springs, one of said additional contact springs arranged on said one side of said movable contact arm and another of said additional contact springs arranged on said opposite side thereof.
- 6. The rotary contact arrangement of claim 5 including a first additional spring retainer pin arranged through one end of each of said additional contact springs and through said additional sidearms, at an end of said additional sidearms opposite said additional bight, said additional retainer pin defining a first pair of additional opposing retainer pin ends, said pair of opposing additional retainer pin ends being positioned within additional carrier slots on the rotor plates perimeters.
- 7. The rotary contact arrangement of claim 6 wherein each of said rotor plates further define a retainer slot on said perimeter thereof and said additional contact springs include a second additional spring retainer pin arranged through another end thereof, said second additional retainer pin defining a second pair of opposing additional retainer pin ends, said second pair of opposing additional spring retainer pin ends being arranged within said retainer slots.
- 8. A circuit breaker interior assembly comprising:a line strap arranged for connection with an electric circuit and a load strap electrically connecting with said line strap and arranged for electrically connecting with associated electrical equipment, said line and load straps being intermittently connected by a rotary contact arrangement, said rotary contact arrangement comprising a pair of opposing circular rotor plates, each of said rotor plates defining a carrier slot on a perimeter thereof; a pair of first and second arc chutes, said first arc chute proximate said line strap and said second arc chute proximate said load strap for quenching arcs occurring upon overcurrent transfer between said line and load straps; a movable contact arm intermediate said rotor plates, said contact arm defining a first movable contact at one end arranged opposite an opposing first fixed contact and a second movable contact at an end opposite said one end arranged proximate a second fixed contact; a pivot pin extending through said rotor plates and said movable contact arm whereby said rotor plates and said movable contact arm rotate in unison; a pair of first contact springs, one of said first contact springs arranged on one side of said movable contact arm and another of said first contact springs arranged on an opposite side thereof; and a U-shaped lever intermediate said rotor plates, said U-shaped lever defining a pair of sidearms joined at one end by a bight, said bight arranged proximate a first shaped surface formed on said contact arm for providing a constant spring force between said first and second fixed and movable contacts.
- 9. The circuit breaker interior of claim 8 including a spring retainer pin arranged through one end of each of said contact springs and through said sidearms, at an end of said sidearms opposite said bight, said retainer pin defining a pair of opposing retainer pin ends, said retainer pin ends being positioned within said rotor carrier slots.
- 10. The rotary contact arrangement of claim 9 wherein said rotor plates further define a retainer slot on said perimeter thereof and said contact springs include an additional spring retainer pin arranged through another end thereof, said additional spring retainer pin being arranged within said retainer slot.
- 11. The rotary contact arrangement of claim 9 including an additional U-shaped lever intermediate said rotor plates, said additional U-shaped lever defining a pair of additional sidearms joined at one end by an additional bight, said additional bight arranged proximate a second shaped surface formed on said contact arm.
Priority Claims (1)
Number |
Date |
Country |
Kind |
99308745 |
Nov 1999 |
EP |
|
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