Claims:We claim:
1. An arc chute assembly (100) for an electromagnetic contactor, the assembly (100) comprising:
atleast one arc chamber housing (50) having two side walls (10) with an L-shaped rib (7) configuration facing each other inwardly forming a slot therein, each side wall (10) on an inner side being configured with a slanting inner surface (5) having thickness gradually tapering from base to apex, and
atleast one de-ion plate (70) detachably coupling with the atleast one arc chamber housing (50) slot therein, the de-ion plate (70) on a bottom end being slanted from both the lateral sides to facilitate locking with the slanting inner surfaces (5) of the side walls (10) and a top end of the de-ion plate (70) being lanced from top side corners to couple with the L-shaped rib (7) of the arc chamber housing (50),
wherein de-ion plate (70) upon assembly in the arc chamber housing (50) provides maximum surface area to face the arcing between contacts of the electromagnetic contactor.

2. The assembly (100) as claimed in claim 1, wherein the arc chamber housing (50) is a flange-like partially open rectangular projection of an arc chamber.

3. The assembly (100) as claimed in claim 1, wherein the slanting inner surfaces (5) holds de-ion plate (70) firmly to prevent removal thereof from the slot during switching of contacts.

4. The assembly (100) as claimed in claim 1, wherein fitment of de-ion plate (70) in the arc chamber housing (50) enables two L-shaped ribs (7) to remain free from any mechanical stresses during successive braking operations of contactor thereby increase life span.
, Description:Field of the invention

The present invention relates to an arc extinguishing means assembly and more particularly, to an arc chute assembly associated with electric switching devices.

Background of the invention

The electromagnetic contactor is used as a switching device in switchgear for making and breaking of electric circuits. Typical electromagnetic contactor consists of a pair of separable contacts per pole enclosed within the housing, cover and arc quenching device. The arc extinguishing device or an arc quenching device has an arc chamber in which the arc drawn between the two contacts in a breaker contact system is extinguished or quenched. Hence, the design of an arc chamber is very important in this manner. The arc chamber consists of a pair of contacts and an arc chute. The arc chute includes a stack of closely spaced metallic plates called splitter / de-ion plates and two side walls. The metallic plates are generally made up of mild steel and have a groove on the contact side to pull an arc inside the arc chute. The mild steel is used for a splitter plate to pull an arc inside the arc chute due to its ferromagnetic properties. The arc pulled inside the arc chute is split by the splitter plates and extinguished. It is very important to cool the arc and to drag it away from contacts to quench or extinguish an arc effectively. The cooling of the arc is done by the splitter plates.

The US patent applications 2967921, 4568805, and 4375021 disclose the use of mild steel plates which are usually insulated from one another. The de-ion plates disclosed in the cited patents are composed of a ferromagnetic material having either ‘J’ or ‘U’-shaped forms. Parallel plates are grouped and assembled in housing with the help of insulated sheets. Figure 1 illustrates prior design from US patent no. 2967921, wherein the assembly ‘X’ shows parallel de-ion plates being grouped and assembled in housing with the help of insulated sheets. These assemblies are secured to the housing frame with the help of a bolt. Threads are provided in the housing wall itself so that bolt can be fitted inside it. The assembly of such invention requires additional fixing means have resulted in not only complicating the assembly process but also consume extra time in manufacturing.

Specifically, a US patent 7705263B2 teaches an arc chute assembly that comprises a housing having a lateral axis and a quenching portion disposed within the housing. The quenching portion includes, at least, two de-ion plates being spaced along the lateral axis of the housing and each having a cut portion wherein the cut portions are staggered along the lateral axis with respect to one another and are configured to mitigate an arc. The assembly is secured to the housing frame with the help of screw ‘Y’ as shown in Figure 2. The assembly of such invention requires additional fixing means have resulted in not only complicating the assembly process but also consume extra time in manufacturing.

Accordingly, there is a need of a simple and easy arc chute assembly for arc extinguishing device that overcomes the above-mentioned drawbacks of the prior art.

Objects of the invention

An object of the present invention is to provide a simple and time-saving assembly of arc chute assembly with fewer embodiments.

Another object of the present invention is to provide uniquely designed de-ion plates to assemble with an arc chamber without the use of any separate fixing means like screws, nuts or bolts.

Yet another object of the present invention is to avoid unnecessary additional cost for assembly of the arc chute.

Another object of the present invention is to provide cost effective assembly.

Summary of the invention

Accordingly, the present invention provides an arc chute assembly for an electromagnetic contactor. The assembly comprises atleast one arc chamber housing having two side walls with an L-shaped rib configuration facing each other inwardly to form a slot and atleast one de-ion plate removably coupling within the slot of the arc chamber housing. The side walls on the inner side are configured with a slanting inner surface having thickness gradually tapering from base to apex. The de-ion plate on a bottom end is slanted on the lateral sides to facilitate locking with the slanting inner surfaces of the side walls and a top end of the de-ion plate being lanced from top side corners to couple with the L-shaped rib of the arc chamber housing. The de-ion plate upon assembly in the arc chamber housing provides maximum surface area to face the arcing between contacts of the electromagnetic contactor. The arc chamber housing is a flange-like partially open rectangular projection of an arc chamber. The slanting inner surfaces holds the de-ion plate firmly and preventing removal thereof during switching of contacts.

Brief description of the drawings

Other features, as well as the advantages of the invention, will be clear from the following description.

In the appended drawings:

Figure 1 shows a side view of an arc chute assembly of a prior art;
Figure 2 show an isometric view of an arc chute assembly of another prior art;
Figure 3 shows a perspective view of an arc chute assembly, in accordance with the present invention;
Figure 4a shows an exploded view of the arc chute assembly, in accordance with the present invention;
Figure 4b shows a perspective view of the arc chute assembly of a de-ion plate within a slot of an arc chamber housing, in accordance with the present invention;
Figure 5 shows a front sectional view along A-A’ of the slot of the arc chamber housing, in accordance with the present invention, and
Figure 6 shows a perspective view of the de-ion plate, in accordance with the present invention.

Detailed description of the invention

The foregoing objects of the present invention are accomplished and the problems and shortcomings associated with the prior art, techniques and approaches are overcome by the present invention as described below in the preferred embodiment.

The present invention provides an arc chute assembly with a unique arrangement for a de-ion plate in an arc chamber housing of an electromagnetic contactor for an electric switching / circuit breaker device. The present invention serves the purpose of functioning without using extra fixing means for fixing the two functioning elements the de-ion plate and the arc chamber housing.

The present invention is illustrated with reference to the accompanying drawings, throughout which reference numbers indicate corresponding parts in the various figures.

Referring to figures 3 to 5, various views of an arc chute assembly (100) for an electromagnetic contactor (Not Shown) are illustrated. The arc chute assembly (100) comprises of atleast one arc chamber housing (50) (herein after ‘the arc chamber housing (50)’) and atleast one de-ion plate (70) (herein after ‘the de-ion plate (70)’).

The arc chamber housing (50) is a flange-like partially open rectangular projection of an arc chamber (Not numbered) which forms a slot (Not numbered) for insertion of the de-ion plate (70). The arc chamber housing (50) may be constructed with any material that may suitably withstand the inherent heat given off by a breaker assembly while not substantially interfering with the circuit breakers required magnetic properties. The arc chamber housing (50) has two side walls (10) with an L-shaped rib (7) configuration facing each other inwardly. Both the side walls (10) on an inner side are designed to have a slanting inner surface (5) with thickness getting gradual taper from base to apex so as to form a gradually increasing the slot area increasing from base to apex as shown in figure 4. The slanting angle of the inner surfaces (5) of the slot can be predetermined in accordance with the width of the de-ion plate (70) inserted therein. The slanting inner surfaces (5) holds the de-ion plate (70) firmly to prevent removal thereof from the slot during switching of contacts.

Referring to figure 6, the structure and profile of the de-ion plate (70) are illustrated. The de-ion plate (70) is a flat plate with made up of ferromagnetic material. The dimensions of the de-ion plate (70) are designed to detachably /removably couple with the slot of the arc chamber housing (50) as per the end use application. A bottom end of the de-ion plate (70) is slightly slanted on the lateral sides to facilitate locking of the de-ion plate (70) with the slanting inner surfaces (5) of the side walls (10) of the arc chamber housing (50). In preferred embodiment of the present invention, the range for slanting angle of inner surfaces (5) of the side walls (10) is up to 0.5 ° (Degree). A top end of the de-ion plate (70) is lanced from top side corners to couple with the L-shaped rib (7) of the arc chamber housing (50). The depth of lancing is determined in accordance with the width available in the slot of the arc chamber housing (50). In accordance with the present invention, the range for lancing is preferably up to 50 % of thickness of plate as per end use intended. Upon assembly, the lanced portion of de-ion plate (70) do not completely rest on the inner walls of L-shaped ribs, only half surface of the de-ion plate (70) touches to the inner walls of L-shaped ribs. Lesser surface area of de-ion plate (70) in touch with L-shaped rib (7) of the side walls (10) facilitates to prevent the transfer of stress to L-shaped ribs. Hence, proper resting of the de-ion plate (70) on the side walls (10) ensures that the internal stresses developed due to lancing operation will not pass on the L-shaped ribs (7). Thus, the fitment of the de-ion plate in the arc chamber housing (50) enables two L-shaped ribs (7) to remain free from any mechanical stresses during successive braking operations of contactor which results in increasing life span. The slanting inner surfaces (5) of arc chamber housing (50) and top lancing of the de-ion plate (70) ensure proper fitment of the de-ion plate (70) in assembled condition of the arc chute assembly (100).

In an alternate embodiment, an inner surfaces (Not Shown) of two side walls (Not Shown) is designed to be straight and a bottom end (Not Shown) of the de-ion plate (Not Shown) is straight on the lateral sides to facilitate locking of the de-ion plate (Not Shown) with the straight inner surfaces of the side walls (Not Shown) of the arc chamber housing (Not Shown).

The de-ion plate (70) upon assembly in the arc chamber housing (50) provides maximum surface area to face the arcing between contacts of the electromagnetic contactor. In an event of AC (Alternate Current) arcing, eddy currents are induced in the de-ion plate (70) to create the magnetic blast field which pulls the arc away from the contacts and consequently lengthens the arc such that arc resistance will increase to quench quickly. Proposed design of the present invention is for arrangement of single de-ion plate in the arch chamber which helps for extinguishing the arc. The arrangement of single de-ion plate is beneficial in those electromagnetic contactor designs where assembly space is the one of the main constraints.

Advantages of the invention

1. The arc chute assembly (100) provides a simple and time-saving assembly using fewer embodiments.
2. The arc chute assembly (100) facilitates a cost-effective assembly.
3. The arc chute assembly (100) avoids unnecessary additional cost for assembly of the arc chute.

The foregoing descriptions of specific embodiments of the present invention have been presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the present invention to the precise forms disclosed, and obviously many modifications and variations are possible in light of the above teaching. The embodiments were chosen and described in order to best explain the principles of the present invention and its practical application, and to thereby enable others skilled in the art to best utilize the present invention and various embodiments with various modifications as are suited to the particular use contemplated. It is understood that various omissions and substitutions of equivalents are contemplated as circumstances may suggest or render expedient, but such omissions and substitutions are intended to cover the application or implementation without departing from the spirit or scope of the claims of the present invention.