US2811612A - Load break interrupter - Google Patents

Description

Oct. 29, 1957 G. L. ATKINSON LOAD BREAK INTERRUPTER Filed Feb. 23, 1956 ATTORNEY Unite States Patet LOAD BREAK INTERRUPTER Gerald L. Atkinson, North Chili, N. Y., assignor to McGraw-Edison Company, a corporation of Delaware Application February 23, 1956, Serial No. 567,263

4 Claims. (Cl. 200-144) This invention relates to improvements in a load break interrupter for use in electric circuits.

The load break device herein disclosed is intended primarily for use in combination with a circuit breaker in substantially the same manner as disclosed in my copending application Serial No. 427,557, filed May 4, 1954, for Circuit Interrupter Devices and issued as Letters Patent No. 2,785,254, March 12, 1957. The device herein disclosed momentarily carries the full load of an electric line after the circuit breaker has been operated to open position and then quickly interrupts the load within the confines of an expulsion chamber thereby avoiding damage to conductive parts of the circuit breaker.

An object of this invention is to provide in an interrupter, a pair of arcing contacts which are rapidly separated to draw an are into an expulsion chamber prior to movement of the interrupter to open circuit position, the interrupter then moving to open circuit position under the control of the circuit breaker.

Another object is to provide a pair of arcing contacts which are separated relative to each other with a snap action movement to draw an are into an expulsion chamber.

A further object is to provide an interrupter in which the arcing contact is moved into an expulsion chamber with a snap action prior to movement of the interrupter to full open position and in which the arcing contact is automatically returned to closed position with a snap action movement when the interrupter is in open position.

It is also an object to provide for a load break interrupter, arcing contacts which when separating draw an are between areas thereon disposed at points oifset from the normal contact areas, thereby avoiding damage to the contact areas when the contacts are separated.

In the drawings:

Fig. l is a longitudinal sectional view of the interrupter as it appears when the circuit breaker is in either closed or full open position.

Fig. 2 is a similar view showing the relative position of the elements immediately preceding load breaking operations after the circuit breaker is disconnected.

The interrupter herein disclosed embodies a hinge member comprising a sleeve 11 having a threaded aperture 12, a threaded annular boss 13, and a pair of substantially parallel pivot arms 14 each provided with a pintle 15 pivotally mounted intermediate the ends of a pair of parallel circuit breaker bars (not shown). A tube 16 of insulating material, is threaded at one end into the threaded aperture 12 and is provided at the opposite end with a metal ferrule 17 having an aperture 18 concentric with the tube.

The tube 16 has a bore 19 terminating in a shoulder 20 adjacent to a smaller bore 21. Fitting snugly within the bore 19 is an insulating sleeve 22 composed of a material which, under the influence of heat, will generate or emit an arc extinguishing gas. The inner diameter of the sleeve 22 is substantially the same as that of the bore 21. As indicated, the diameter of the aperture 13 ice in the ferrule 17 is such as to provide an annular shoulder projecting inwardly of the bore 21.

A metallic tube 25 having vents 26 is threaded on the base 13 on the sleeve 11. A closure cap 27 is threaded on the upper end of the tube 25 and is provided with a centrally recessed portion 28 which receives a second metallic tube 29 extending to and engaging the upper end of the tube 16. The tube 29 is provided with a multiplicity of venting apertures 30. Secured to the exterior of the tube 29 by any suitable means, such as a rivet 31, is a resilient conductive strip 32 having its upper portion 33 projecting angularly into the interior of the tube 29 through an elongated aperture 34 and terminating in an arcuate latching end 35. The opposite end portion 36 of the strip 32 is provided with a contact block 37 secured thereto and positioned in a slot 38 to extend into the tube 29. For reasons which will be later apparent, the block 37 is beveled at 39.

The load break mechanism is mounted within the tubes 16 and 29 and is movable longitudinally thereof. This mechanism comprises an insulating rod 45 embodying arc extinguishing material, such as Lucite, a metallic rod 46 secured to the lower end of the insulating rod and having a cylindrical contact block 4'7 secured thereto adjacent the rod 45, and a metallic sleeve 48 surrounding the rod 46 and movable longitudinally thereof.

The upper end of the insulating rod 45 is provided with a latch member 50 secured thereto and having an annular groove receiving the latching end 35 on the resilient strip 32. intermediate the ends of the metallic rod as is an enlarged cylindrical portion 51, the function of which will hereafter become apparent. The lower end of the rod 46 is flanged at 52. The upper end of the metallic sleeve 48 is closed by an apertured cap 53 secured thereto in any suitable manner, such as welding and slideable on the rod 46. This cap is cylindrical and projects beyond the sleeve 48 to provide an annular shoulder.

The lower end of the sleeve 48 is capped by a latching member 54 having an annular groove 55 for receiving biased contact prongs (not shown). An expansion coil spring 6%), surrounding the rod 46, is positioned within the sleeve 48 and engages the flange 52 on the rod 46 and cap 53 on the sleeve 48. A second expansion spring 61 is positioned within the tube 16, surrounding the sleeve 48, and engages the cap 53 on the sleeve 48 and the flanged portion on the ferrule 17.

Normally, the springs 64) and 61 bias the elements of the load break mechanism to the relative positions illustrated in Fig. 1. When these relative positions prevail, the ioad break mechanism will be in either open or closed circuit positions relative to an electric line. Assuming that the mechanism is in closed position, then current will flow from the cap 54 to the pintles 15 through the sleeve .8, cap 5'3, spring as, rod 46, contact blocks 47 and 37, strip 32, tube 29, tube 25, sleeve 11 and arms 14.

Assuming again that the load break mechanism is pivotally mounted on a pair of spaced circuit breaker bars, as in my aforesaid Letters Patent No. 2,785,254, then operation of the circuit breaker to open position will cause the sleeve 4-8 to recede from the tube 16, as indicated in Fig. 2, by reason of the latched engagement of the cap 54 with a jaw contact (not shown).

As the sleeve 4% is withdrawn from the tube 16, it wiil, through the medium of the cap 53 at its upper end, compress the springs as and 61. Continued movement of tube 48 outwardly of the tube 16 will engage the cap 53 with enlarged cylindrical portion 51 on the rod 46 at which time the rod 46 will move with the sieeve 48 and withdraw the latch member 5% at the upper end of the 37 is beveled at one corner.

3 rod 45 from engagement with latching end 35 on the strip 32.

When the latch member 50 and latching end 35 are disengaged, the spring 60 takes over and separates the contact blocks 37 and 47 by moving the contact block 47 downwardly into the insulating sleeve 22 with a snap action movement, thus extending an are between the contact blocks and subjecting the arc to an arc extinguishing material evolved by heat of the are from the sleeve 22.

Subsequent to extinguishment of the arc, further movement of the sleeve 48 outwardly of the tube 16 will be opposed by the compacted spring 61 and compel the latching cap 54 to disengage the jaw contacts (not shown) whereupon the spring 61 will be released and, with a snap action movement, return the various movable elements to the relative relationship shown in Fig. 1.

It has previously been noted that the contact block It will now be noted that the cylindrical contact block 47 is provided with a tapered end adjacent the insulating rod 45. When the contact blocks 37 and 47 are separated in the manner previously described, the are established between them will play on beveled surface of the contact block 37 and the tapered end of the contact block 47, rather than between the contact surfaces of the blocks, thus avoiding burning and mutilation of the contact surfaces during load break op eration.

Preferably the sleeve 22 and rod 45 are composed of materials which will evolve an arc extinguishing material in the presence of an are. When the rod 45 is being drawn into the sleeve 22, an are established between the contact blocks 37 and 47 will be confined between the opposing surfaces of the rod and sleeve and the heat of the arc will cause arc extinguishing material to be evolved. To avoid pressure build up due to evolution of the arc extinguishing gases, the cylinder 29 is apertured at 30 to permit expansion into the space between the cylinders 29 and 20 and outwardly of the cylinder 20 at the openings 26.

Due to the fact that the cylinders 20 and 29, particularly cylinder 26, expose considerable surfaces to the hot gases and quickly reduce the temperature thereof, so that, in actual practice, the volume of gases escaping from the openings 26 in the cylinder 26 is considerably reduced from that generated in the presence of an arc.

From the foregoing it will be apparent that a novel load break interrupter has been disclosed, which provides a snap action interruption of electric circuit and extinguishment of an arc prior to movement of the interrupter to open circuit position and which, subsequent to movement of the interrupter, provides a snap action return of the load interrupting mechanism to its normal position for subsequent load interrupting operation.

It will also be apparent that a novel arrangement of arc interrupting contacts has been provided which, on separation of the contacts, disposes an arc therebetween at points thereon remote from the contact surfaces, thus avoiding burning and damage to the contact surfaces.

I claim:

1. In a load interrupter for an electric circuit, the combination with an insulating tube and a vented electrically conductive tube projecting from one end of and concentrically secured to said insulating tube, of a resiliently supported contact including a latch member projecting into said conductive tube, a cap secured to the other end of said insulating tube and apertured centrally thereof to provide an annular shoulder inward of said insulating tube, an elongated conductive sleeve projecting into said insulating tube through the aperture in said cap, a conductive latching contact closing the outer end of said sleeve and normally positioned adjacent said cap, a centrally apertured annular closure member closing the inner end of said sleeve and providing an annular shoulder radially of said sleeve and normally positioned at the juncture line of said insulating and conductive tubes, a first expansion coil spring in said insulating tube and surrounding said sleeve, said first spring engaging said annular shoulders on said cap and said closure member thereby biasing said sleeve inwardly of said insulating tube and maintaining said latching contact and closure member in said normal positions, a conductive rod projecting into said sleeve through the aperture in said closure member, a contact secured to said rod and normally adjacent said closure member exteriorly of said sleeve and electrically engaging the first mentioned contact, a flange on said rod and positioned in said sleeve remote from said closure member, said rod having intermediate its ends an enlarged element engageable with said closure member, a second coil spring within said sleeve and surrounding said rod, said second spring engaging said flange and closure member and normally biasing said rod inwardly of said sleeve to normally maintain said second contact adjacent said closure member, and latching means carried by said rod normally releasably engaging said latching member in said conductive tube.

2. In a load interrupter for an electric circuit, the combination with an insulating tube having exteriorly thereof at one end a stationary contact and latching means, of a sleeve extending into said tube from the other end thereof and having a latching contact exteriorly of said tube at said other end, said sleeve extending substantially the full length of said tube when innormal position, a rod extending into said sleeve from said one end of said tube and having contact normally engaging said stationary contact and having a latch member normally engaging said latching means, said rod extending substantially the full length of said sleeve, a first expansion spring in said sleeve and surrounding said rod, one end of said first spring engaging said sleeve at the end thereof adjacent said one end of said tube, the other end of said spring engaging said rod at a point thereon most remote from said contact, a second expansion spring in said tube and surrounding said sleeve, one end of said second spring engaging the end of said sleeve adjacent said one end of said tube and the other end of said second spring engaging said tube ad jacent said other end thereof, and inter-engageable means on said rod and sleeve effective to move said rod simultaneously with said sleeve subsequent to a predetermined relative movement therebetween.

3. In a load interrupter for an electric circuit, the combination with an elongated insulating member having at one end a stationary contact and latching means, of an elongated actuator carried by and movable longitudinally of said member, a movable contact normally engaging said stationary contact and including a latch releasably engaging said latching means, said movable contact and latch being movably mounted on said actuator, a first spring on said actuator having one end in engagement therewith and the other end in engagement with said movable contact, a second spring on said insulating member having one end thereof in engagement with said member and the other end thereof in engagement with said actuator, and means adapted to interengage said actuator and latch subsequent to a predetermined relative movement therebetween, whereby energy accumulated in said springs releases said latch and affords a snap action separation of said contacts and thereafter returns all movable elements to their normal positions for circuit closing operations.

4 In a load interrupter for an electric circuit, the combination with an insulating support having a stationary contact, an actuator movably supported by said support, and a contact carrier movably supported by said actuator and having a second contact normally engaging said stationary contact, releasable latch means normally holding said carrier immobile, inter-engageable means on said actuator and carrier operative subsequent to a relative predetermined movement therebetween to effect simultaneous movement thereof whereby to release said latch means, and spring means normally maintaining actuator and carrier immobile relative to said support and to each other, said spring means accumulating stored energy on movement of said actuator and quickly separating said contacts upon simultaneous movement of said actuator and carrier and thereafter returning said actuator and carrier to their positions normally maintained by said spring means.

References Cited in the file of this patent UNITED STATES PATENTS Heinrich Oct. 18, 1921 Allan Sept. 1, 1931 Seaman Sept. 8, 1936 Skeats July 20, 194-8 Driescher Feb. 9, 1954

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