CLIAMS:1. An auxiliary contact block for electrical contactor, the auxiliary contact block comprising:
a moving contact (3) further comprising
at least one screw (9) with at least one screw head (4) and at least one elongated body; and
at least one spring (5) surrounding the at least one elongated body; and
a stationary contact (1,2,10,20) comprising at least one conductor with at least one contact button (8) attached at its end.

2. The auxiliary contact block according to claim 1, wherein the movable contact (3) is stationary at one position.

3. The auxiliary contact block according to claim 1, wherein the at least one screw (9) is movable in translational motion.

4. The auxiliary contact block according to claim 1, wherein the at least one screw (9) is capable of rotating.

5. The auxiliary contact block according to claim 1, wherein the at least one contact button (8) is used to provide an electrical coupling.

6. The auxiliary contact block according to claim 1, wherein the at least one contact button (8) is stationary.

7. The auxiliary contact block according to claim 1, wherein the at least one contact button (8) is movable.

8. The auxiliary contact block according to claim 1, wherein the at least one screw (9) further comprises of a protrusion (6) to mechanical couple with the at least one wall (7).
,TagSPECI:TECHNICAL FIELD
The present subject matter described herein, in general relates to an electrical contactor in electrical circuits or switchgear’s and, more particularly, to a contact used as an auxiliary contact for electrical contactor in electrical circuits or switchgear’s.

BACKGROUND
It is common to use contact block having either Normally-closed (NC) or Normally-open (NO) contacts to control the current flowing in electrical circuit. The contact block generally consists of first pair of stationary contacts and pair of movable contacts attached to actuator. The actuator is biased such that movable contacts are either in closed or open position with relation to first stationary contacts. It is also known to have second pair of stationary contacts spaced apart from the first pair of stationary contacts such that the pair of movable contacts is located between the first and second stationary contacts, thus allowing the contact block to have one Normally-open contact and one Normally-closed contact. The extra set of stationary contacts increases the physical size of contact block and significantly increases the cost since two additional stationary contacts are required. If an application requires two contacts of same type (either NO or NC) it is common to stack contact blocks together. Since this adds additional cost of contact block, it would be desirable to have contact block which is comparable in cost to a single function contact block as described above and yet it is easily converted from Normally-open to Normally-closed contact or vice versa.

In other types of circuit control devices it is sometimes required to operate an additional control circuit by same operator as that of main circuit. For example contactor auxiliary circuit contacts are controlled by operator which moves along with movement of electromagnet of contactor. For these applications it is common to provide an auxiliary contact. The auxiliary contact is generally contained within an enclosure and includes a pair of stationary contacts, a pair of movable contacts mounted on actuator, a biasing spring, and a pair of wire terminal connectors. The auxiliary contact enclosure is mounted on the outside of the circuit control device enclosure in a location that permits access to primary contactor actuator such that the auxiliary contact can be operated simultaneously with the primary contactor.

The auxiliary contacts, like the contact blocks, are available in either a Normally-open or Normally-closed function and must be purchased separately as an accessory for the control device. This means that an inventory of both Normally-open and Normally-closed contacts is required separately to insure that the desired auxiliary contact is available when required. It would therefore be desirable to have a circuit control device with auxiliary contact that can be easily converted from Normally-open to a Normally-closed contact (or vice versa).

In prior contact block the contacts are either Normally-closed or Normally-open. These contacts cannot be converted to desired contacts. For example if some application requires two Normally-closed contacts, the user need to purchase two contact blocks, since one contact block contains one Normally-closed and one Normally-open contact only. Thus when user purchase two contact blocks he is getting two additional Normally-open contacts which is of no use to him. This will also add to additional cost and space.

In present technologies, the contact blocks are having either Normally-closed or Normally-open contacts to control the current flowing in electrical circuit. These blocks can be mounted on outer surface of electrical contactor and works simultaneously with the operation of contactor main contacts. The stationary contacts of contact block can be converted to either Normally-closed or Normally-open contacts by moving the actuator in translational movement. The actuator contains moving contacts which bridges the stationary contacts, thus forming either Normally-closed or Normally-open contacts.

So there exists a need to provide a solution to all the above mentioned problems, by providing a normally-closed contact that can be converted to Normally-open contact and vice-versa. Thus user can convert contacts according to need and using same contact block. Further, the proposed solution must be cost and time efficient as the additional cost and space is saved.

SUMMARY
This summary is provided to introduce concepts related to an auxiliary contact block for electrical contactor to provide normally-open or normally-closed electrical contact. This summary is not intended to identify essential features of the subject matter nor is it intended for use in determining or limiting the scope of the subject matter.

In one implementation, a normally-closed contact that can be converted to Normally-open contact and vice-versa is provided.

In one implementation, a user can himself convert contacts according to need and using same contact block.

In one implementation, a cost and time efficient solution is proposed.

In one implementation, the present invention discloses a provision to convert Normally-open contact to Normally-closed contact or vice-versa, by just rotation of the spring screw. Thus user will be able to use contacts as per requirement and need not to purchase the additional contacts to meet the requirement.

In one implementation, an auxiliary contact block for electrical contactor is disclosed. The electrical contactor comprises of a moving contact and a stationary contact. The moving contact further comprises of at least one screw and at least one spring. The at least one screw is further provided with at least one screw head (4) and at least one elongated body. The at least one spring is surrounds the at least one elongated body. The stationary contact further comprises of at least one conductor having at least one contact button attached at its end.

BRIEF DESCRIPTION OF THE DRAWINGS
The detailed description is described with reference to the accompanying figures. In the figures, the left-most digit(s) of a reference number identifies the figure in which the reference number first appears. The same numbers are used throughout the drawings to refer like features and components.

Figure 1 illustrates a general view of rotary convertible contact assembly using spring screw is shown, in accordance with an embodiment of the present subject matter.

Figure 2 illustrates the rotary convertible contact assembly using spring screw in first position (Normally-closed position) is shown, in accordance with an embodiment of the present subject matter.

Figure 3 illustrates the rotary convertible contact assembly using spring screw when operated from first position is shown, in accordance with an embodiment of the present subject matter.

Figure 4 illustrates the rotary convertible contact assembly using spring screw in second position when actuator rotated through 90 degree angle (Normally-open position) is shown, in accordance with an embodiment of the present subject matter.

Figure 5 illustrates the rotary convertible contact assembly using spring screw when operated from second position is shown, in accordance with an embodiment of the present subject matter.

Figure 6 illustrates the spring screw used in present invention is shown, in accordance with an embodiment of the present subject matter.

Figure 7 illustrates the contact block mounted on surface of electrical contactor as generally used in current technology (prior art) is shown, in accordance with an embodiment of the present subject matter.

DETAILED DESCRIPTION
Preferred embodiments of the present disclosure will be described herein below with reference to the accompanying drawings. In the following description, well-known functions or constructions are not described in detail to avoid obscuring the present disclosure in unnecessary detail.

The following description with reference to the accompanying drawings is provided to assist in a comprehensive understanding of exemplary embodiments of the invention as defined by the claims and their equivalents. It includes various specific details to assist in that understanding but these are to be regarded as merely exemplary. Accordingly, those of ordinary skill in the art will recognize that various changes and modifications of the embodiments described herein can be made without departing from the scope and spirit of the invention. In addition, descriptions of well-known functions and constructions are omitted for clarity and conciseness.

The terms and words used in the following description and claims are not limited to the bibliographical meanings, but, are merely used by the inventor to enable a clear and consistent understanding of the invention. Accordingly, it should be apparent to those skilled in the art that the following description of exemplary embodiments of the present invention are provided for illustration purpose only and not for the purpose of limiting the invention as defined by the appended claims and their equivalents.

It is to be understood that the singular forms “a,” “an,” and “the” include plural referents unless the context clearly dictates otherwise.

By the term “substantially” it is meant that the recited characteristic, parameter, or value need not be achieved exactly, but that deviations or variations, including for example, tolerances, measurement error, measurement accuracy limitations and other factors known to those of skill in the art, may occur in amounts that do not preclude the effect the characteristic was intended to provide.

Accordingly, present invention is an auxiliary contact block for electrical contactor to provide normally-open or normally-closed electrical contact is disclosed.

Construction of the connector assembly of the present invention is explained with reference to the accompanying figures.

List of components:
1. Stationary contact (1)
2. Stationary contact (2)
3. Moving contact (3)
4. Screw head (4)
5. Spring (5)
6. Protrusion on screw (6)
7. Enclosure wall (7)
8. Contact buttons (8)
9. Screw (9)
10. Stationary contact (10)
11. Contact block (11)
12. Contactor (12)
13. Stationary contact (20)

In one implementation, an auxiliary contact block for electrical contactor is disclosed. The electrical contactor comprises of a moving contact (3) and a stationary contact (1, 2, 10, 20). The moving contact (3) further comprises of at least one screw (9) and at least one spring (5). The at least one screw (9) is further provided with at least one screw head (4) and at least one elongated body. The at least one spring (5) is surrounds the at least one elongated body. The stationary contact (1, 2, 10, 20) further comprises of at least one conductor having at least one contact button (8) attached at its end.

In one implementation, the movable contact (3) is stationary at one position. The at least one screw (9) is movable in translational motion. Further, the at least one screw (9) is capable of rotating.

In one implementation, the at least one contact button (8) is used to provide an electrical coupling. The at least one contact button (8) is stationary. Further, in one example, the at least one contact button (8) may be movable.

In one implementation, the at least one screw (9) further comprises of a protrusion (6) to mechanical couple with the at least one wall (7).

The present invention discloses a convertible Normally-open or Normally-closed electrical contact using spring screw. The convertible contact comprises a movable contact supported between screw head and spring of the spring screw. The movable contact is fixed to first position and it can be moved to second position by moving the screw in translational motion and rotating to lock at this second position. Stationary contact module includes a pair of conductors; each with a stationary contact attached at its end is employed to complete electrical contact. By selectively moving the movable contact in either first or second position, either Normally-closed or Normally-open electrical contact can be achieved.

Referring now to figure 1 illustrates a general view of rotary convertible contact assembly using spring screw is shown, in accordance with an embodiment of the present subject matter. An exemplary assembly of the convertible contact is provided. The contactor comprises of the moving contact (3) and the stationary contact (1, 2, 10, and 20). The moving contact (3) further comprises of the at least one screw (9) and the at least one spring (5). The at least one screw (9) is further provided with the at least one screw head (4) and the at least one elongated body. The at least one spring (5) is surrounds the at least one elongated body. The stationary contact (1, 2, 10, 20) further comprises of at least one conductor having at least one contact button (8) attached at its end.

Referring now to figure 2 illustrates the rotary convertible contact assembly using spring screw in first position (Normally-closed position) is shown, in accordance with an embodiment of the present subject matter. In one implementation, the stationary contact (1) and the stationary contact (2) are bridged by moving contact (3). The contact buttons (8) are shown. The moving contact (3) is having contact buttons (8) on both side of its surface, while in case if stationary contacts (1, 2, 10 and 20) contact buttons (8) are on one side only. The contact buttons (8) are for better contact of current carrying conductors. The moving contact (3) is supported between screw head (4) and spring (5). The screw (9) can be pressed to move it in a translational motion and can also be rotated.

In first position moving contact (3) is bridging the stationary contacts (1) and (2). Thus there is electrical connection between stationary contact (1) and stationary contact (2). This forms the Normally-closed (NC) contact between stationary contacts (1 and 2) and moving contact (3). The position of protrusion (6) is above the enclosure walls (7). Since the motion of screw (9) is coupled with motion of Contactor Bridge (not shown in figure), when contactor operates it will move the screw (9) in translational motion. Since the spring (5) cannot go through walls (7) it restricts the moving contact (3) from touching lower stationary contacts (10 and 20) When screw (9) moves because of contactor action it moves in a direction shown by thick arrow in figure 3. This will move the moving contact (3) away from the stationary contacts (1 and 2) and consequently opens the contact (1) and (2). Thus Normally-closed contact will open as the contactor operates.

Referring now to figure 3 illustrates the rotary convertible contact assembly using spring screw when operated from first position is shown, in accordance with an embodiment of the present subject matter. In one implementation, figure 3 shows the rotary convertible contact when operated from first position so as to open the contacts. Thick arrow shows the translational motion of screw (9) and thus moving contact (3). Thus operating the screw (9) in a direction shown by thick arrow in figure Normally-closed contact can be opened.

Referring now to figure 4 and figure 5, illustrates the rotary convertible contact assembly using spring screw in second position when actuator rotated through 90 degree angle (Normally-open position) is shown, in accordance with an embodiment of the present subject matter, and the rotary convertible contact assembly using spring screw when operated from second position is shown, in accordance with an embodiment of the present subject matter, respectively.

In one implementation, figure 4 shows the rotary convertible contact assembly in second position. When application requires Normally-open contact it can be achieved by pressing the spring screw (9) and rotating the spring screw (9) in 90 degree angle. Thus making the protrusion (6) on the spring screw (9) to engage below the walls (7), shown in figure 4. The moving contact (3) can only move in translational motion, whereas screw can be rotated by 90 degree angle. These translational and rotary motions are shown by thick arrows in figure 4. In this position the moving contact (3) is in between the stationary contacts and is not touching any of stationary contacts (10 or 20). Thus there is no electrical connection between stationary contact (10) and stationary contact (20). This forms the Normally-open contact between stationary contacts (10) and (20). In this position when contactor operates, the spring screw ( 9) further moves down as shown in figure 5, bridging the stationary contacts (10) and (20) and thus making the electrical connection between them. Note that the spring (5) thickness is such that it will rest on walls (7) to maintain contact pressure. Thus Normally-open contact will close as the contactor operates.

In one implementation, figure 5 shows the rotary convertible contact when operated from second position so as to close the contacts. Thick arrow shows the translational motion of spring screw (9) and hence translational movement of movable contacts (3). Thus operating the spring screw (9) in a direction shown by thick arrow in figure 5 Normally-open contacts can be closed.

Referring now to figure 6 illustrates the spring screw used in present invention is shown, in accordance with an embodiment of the present subject matter. In one implementation, figure 6, shows the spring screw. It consists of spring supported between screw head and protrusion on screw.

Referring now to figure 7 illustrates the contact block mounted on surface of electrical contactor as generally used in current technology (prior art) is shown, in accordance with an embodiment of the present subject matter. In one implementation, the figure 7 shows the contact block (11) used in present technology. It is placed above the surface of contactor (12) and it contains inside it, the two pairs of stationary contacts and a pair of moving contacts (not shown in figure). The contact block (11) generally consists of one Normally-closed and one Normally-open contact. The movable contacts are supported on both ends of spring which is enclosed within a cavity inside the actuator. This actuator moves in translational direction so as to open or close the contacts. This assembly is enclosed within housing. The housing is mounted on the surface of contactor as shown in figure 6.

Exemplary embodiments discussed above may provide certain advantages. Though not required to practice aspects of the disclosure, these advantages may include those provided by the following features:

One feature of the invention is that, it provides a rotary convertible contact which can be selectively and easily changed between a Normally-open function and a Normally-closed function by the user. User need not to purchase separate Normally-open and Normally-closed contacts.

Another feature of the invention is that, the convertible contact of the present invention can be used as the primary contact of a contact block or an auxiliary contact of other circuit control devices.

Another feature of the invention is that, the method of operation of actuator is rotary plus translational as opposed to translational in prior designs.

Yet another feature of the invention is that, the number of stationary contacts and moving contacts are reduced thus reducing cost of assembly.

Still another feature of the invention is that, the user is provided with flexibility to choose required contact depending on his requirement or application.
Although implementations for an auxiliary contact block for electrical contactor to provide normally-open or normally-closed electrical contact have been described in language specific to structural features and/or the methods, it is to be understood that the appended claims are not necessarily limited to the specific features or methods described. Rather, the specific features are disclosed as examples of, an auxiliary contact block for electrical contactor to provide normally-open or normally-closed electrical contact.

It is intended that the disclosure and examples above be considered as exemplary only, with a true scope and spirit of disclosed embodiments being indicated by the following claims.