FIELD OF INVENTION
The invention relates to terminals and particularly to terminals for electrical connections. More particularly, the invention relates to electrical terminals mountable on mounting rails and which are usable for feed through as well as ground connection and which can also be internally interconnected.
BACKGROUND OF THE INVENTION
Terminals for electrical connection and which are suitable for mounting on a mounting rail of internationally standard shape are known for decades. They are essentially electrical connectors which are devices for joining conductors in electrical circuits, coming from two or more different equipment or source. Such connections are generally non-permanent type and can be easily connected or disconnected several time without change in property of the conductor or electrical terminal.
From the point of view of electrical application, the electrical terminals either connect
(a) a conductor coming from one equipment or source to another, or
(b) a plurality of conductors from equipment or source to common potential called ground or earth.
There are three major types of mounting rail, also generally known as DIN rail:
i. Top hat section or type Ω, with hat-shaped cross section. ii. C section iii. G section
The mounting rail is made of metal, generally mild steel, which is electroplated for protection against atmospheric corrosion. The mounting rail, in additional to its basic use as mounting terminals, is also generally connected to the common potential, also called ground or earth potential. Essentially, mounting rail is good conductor of electricity and suitable for earthing connection.


Electrical terminals generally have a conducting link through which conductors get connected, either by the use of a screw connection or some kind of screw-less connection. Patent No: US4171861 gives a fair illustration of this prior art.
Electrical terminals which are used for connection to ground potential have another conducting part, which is connected to busbar and also to the mounting rail. Patent No: DE3339365, CN101533969 illustrate two different concepts for this application.
At times, several conductors need to be terminated on an electrical terminal and the sum total cross-section of conductors exceeds the capacity of the electrical terminal. In such a case, and in other situations needing inter connection, arrangements are designed by which more than one electrical terminal is interconnected. Patent No: DE3625240 illustrates this aspect and it becomes clear that a multi-legged plug is made use of, which is engaged in corresponding opening in the conducting link. Patent No: DE10324144 discloses an electrical terminal with modular grounding.
The electrical connection requirements are getting complex. Grounding requirements are also rising due to onset of electronics and therefore electromagnetic shielding in many products. A single electrical terminal is expected to facilitate feed through connection, as well as interconnection. Also, it should be possible to add ground connection in any electrical connection at a later date. For creating provisions of interconnection and ground connection, one generally needs to locally reduce the effective cross-section of busbar. From the performance point of view, on the other hand, the overall resistance of the busbar is critical so as to achieve optimum temperature rise and short circuit capability.
There is need to have a design which addresses the comprehensive need of feed through, optional grounding as well as intra-connection provision in a single electrical terminal. This need is difficult to be met without compromising performance and reliability. Particularly, the reliability of the ground connection is of significance and more particularly the reliability of earthing with modularity becomes an engineering challenge.


None of the prior arts address the electromechanical reliability aspect. Our inventive design addresses this need & thus solves this problem.
OBJECTIVE OF THE INVENTION
The objective is to invent an electrical terminal suitable for mounting rails, for feed through application and with a provision for grounding connection.
Another objective is to invent an electrical terminal suitable for mounting rails having a provision to add grounding at a later date at site.
Another objective is to invent an electrical terminal which has provision for intra connecting different electrical terminals.
Another objective is to have reliable grounding connection mechanically as well as electrically.
Another objective is to be able to add the grounding properly without the need of any tool or skill.
Another objective is to be able to remove the grounding with tool and minimum skill.
SUMMARY OF THE INVENTION
Our invention is an Electrical Terminal for feed through, ground and intra-connection. The electrical terminal is suitable for fixation on DIN type mounting rail. The electrical terminal is assembled in an insulating housing. The upper half of the insulating housing supports a conducting link and a plurality of connection device and has a plurality of openings through which conductors can be fixed. The insulating housing also has a plurality of plug openings through which intra-connection plug can reach a plurality of sockets in the conducting link. The conducting link has the sockets and a receptacle. The lower half of the insulating housing has a slit through which a grounding clamp can be assembled. The grounding clamp has four zones – a twin male connector, a plurality of one-sided lances, a hinge end and a latch end. The twin male connector is eccentrically placed in the grounding clamp. The grounding clamp provides a plurality of independent grounding contacts with the mounting rail. The electromechanical connection between conducting link and grounding clamp is auto adjusting type so as to ensure


reliable connection irrespective of manufacturing process and variations in fitment of grounding clamp in the insulating moulding. The grounding clamp can be assembled only in the correct orientation without any skill or tool and can be removed by a trained person with the application of a screw driver. The grounding clamp even if partially inserted during assembly gets properly fitted when mounted on mounting rail.
BRIEF DESCRIPTION OF DRAWINGS
Figure-1 shows an Electrical Terminal for feed through, ground and intra-connection, fixed on a DIN rail; while Figure-1A shows a DIN mounting rail
Figure-2 shows an insulating housing
Figure-3 shows a connecting link engaged with a grounding clamp through an engagement of a twin male connector and a receptacle
Figure-4 shows details of the connecting link. Figure-4A shows details of the receptacle as manufactured by punching process and Figure-4B shows receptacle after removal of a plurality of burr and creating a chamfer.
Figure-5 shows details of grounding clamp and an eccentrically placed twin male connector; while Figure-5A shows profile of the twin male connector.
Figure-6 shows the twin male connector engaged with the receptacle with a convex surface against a burnished area.
Figure-7 shows the insulating house and the grounding clamp in the direction of assembly Figure-8 shows an Electrical Terminal partially fixed on a DIN rail when the grounding terminal is not properly assembled.
DETAILED DESCRIPTION
The invention shall now be described with reference to the preferred embodiment, but the invention can be worked with several variations and should not be construed to be limited to the embodiment described.


Definitions:
Feed Through Electrical Terminal – An electrical terminal that connects a conductor coming from
one equipment or source to another conductor.
Grounding Electrical Terminal – An electrical terminal that connects a conductor from any
equipment or source to common potential called ground or earth.
Intra-connection – Connection between conducting links of a plurality of electrical terminals.
Other terms used are as per general engineering practices.
Figure-1 and 2 shows an Electrical Terminal (10) for feed through, ground and intra-connection. The electrical terminal (10) is suitable for fixation on a DIN type mounting rail (11). The electrical terminal (10) is assembled in an insulating housing (12). An upper half (21) of the insulating housing (12) supports a conducting link (41) and a plurality of connection device (18) and has a plurality of conductor openings (13) through which conductors can be fixed. The insulating housing (12) also has a plurality of plug openings (14) through which an intra-connection plug (not shown) can reach a plurality of sockets (42) in the conducting link (Figure-4). The conducting link (41) has the plurality of sockets (42) and a receptacle (43). A lower half (31) of the insulating housing (12) has a slit (15) through which a grounding clamp (51) can be assembled. The lower half (31) of the insulating housing (12) also has a plurality of one-sided openings (16).
Figure-3, 4 and 5 show the grounding clamp (51) connected to the conducting link (41) by way of an electrical and mechanical connection. The electrical and mechanical connection is formed by an engagement of receptacle (43) on the connecting link (41) with a twin male connector (52) on the grounding clamp (51).
Figure 4, 4A and 4B show details of the receptacle (43). The receptacle (43) is essentially a rectangular opening in the connecting link (41) which can be formed by any known manufacturing process. Punching process is one of the most economical processes of mass production but it leaves irregular inner walls. Notably a rollover (49) on the side of punching, and a fracture (48) and a burr (19) on the other side of the punching direction are hindrances to a


good electrical and mechanical connection formation. The smooth surface, generally known as burnished area (47), is limited to about 30% to 50% of the total area generated due to punching. In the preferred embodiment, the punching direction is maintained always from a side A (44). Consequently, the burr (19) is always created on a side B (45), which is removed by shaving or equivalent known process, so as to create an inclined plane termed as a chamfer (46) and which facilitates easy and complete entry of the twin male connector (52) in the receptacle (43).
The grounding clamp (51) has four zones – a twin male connector (52), a plurality of one-sided lances (54), a hinge end (56) and a latch end (57). The twin male connector (52) is eccentrically placed in the grounding clamp (51) so that the sockets (42) can be accommodated in the connecting Link (41).
The twin male connector in the grounding clamp (51) has an open bifurcation end. A plurality of prongs (55) of the open bifurcation has a convex surface (53) in the distal region of the twin male connector (52).
Figure 3, 6 and 7 shows that when the grounding clamp (51) is inserted in the insulating housing (12) from the slit (15), the twin male connector (52) enters the receptacle (43). When the plurality of one sided lances (54) on the grounding clamp (51) reach the one sided openings (16) on the insulating housing (12), the convex surface (53) of the twin male connector (52) rests on the burnished area (47). Open bifurcation facilitates the prongs (55) to bend towards each other minimally and at the same time the convex surface (53) exerts needed pressure on the burnished area (47). Consequently, a line contact is ensured between the convex surface (53) and the burnished area (47) which is a requisite for effective electrical connection.
The extent to which the grounding clamp (51) can enter the slit (15) is decided by the relative locations of the one sided lances (54) in the grounding clamp (51) and the one sided openings (16) in the insulating housing (12). Consequent to the convex surface (53), it is ensured that electrical contact in the form of the line contact is within the burnished area (47) and never in the roll over (49) or the fracture (48) despite general manufacturing variations.
The grounding clamp (51) provides a plurality of independent grounding contacts with the mounting rail at the hinge end (56) and at the latch end (57).
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A first earthing contact (61) and a second earthing contact (62) are formed at the hinge end while a third earthing contact (63) is formed at the latch end.
To mount the electrical terminal (10) on the DIN rail (11), a leg (58) in the insulating housing is hooked below an arm (17) of the DIN rail (11) and the electrical terminal (10) is turned down and pushed so that a projection (59) in the insulating housing is brought below another arm (20) and the electrical terminal is securely mounted on the DIN rail (11), Figure 1A and Figure 2.
In the event that the grounding clamp (51) is present but inadvertently not fully inserted in the slit (15), as illustrated by Figure 8, it is likely that that the electromechanical connection between the conducting link (41) and the grounding clamp (51) is not proper. In our embodiment, the construction of the leg (58), the projection (59), the first earthing contact (61), the second earthing contact (62) and the third earthing contact (63) is such harmonized that in the process of mounting the electrical terminal (10) on the DIN rail (11), the grounding clamp (51) is pushed so as to restore proper electromechanical connection between the connecting link (41) and the grounding clamp (51).
This is achieved as now described: Consequent to hooking the leg (58) below the arm (17) and turning down the insulating housing (12) of the electrical terminal (10), the second earthing contact (62) comes in contact with the DIN rail (11) early, and pushes the grounding clamp (51) towards the connecting link (41). As the action of turning down and pushing the electrical terminal (10) continues, the third earthing contact (63) comes in contact with the DIN rail (11) and further pushes up the grounding clamp (51) towards the connecting link (41). As the mounting of the electrical terminal (10) completes, the one sided lances (54) reach the one sided openings (16) and the proper electromechanical contact is made between the connecting link (41) and the grounding clamp (51). This can we well understood by referring to Figure 1,1A, 2 and 3.
In other words, the electromechanical connection between the conducting link (41) and the grounding clamp (51) is auto adjusting type so as to ensure reliable connection irrespective of manufacturing process and variations in fitment of grounding clamp (51) in the insulating housing (12).
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Consequent to eccentric placement of the twin male connector (52) on the grounding clamp (51), the grounding clamp (51) can be assembled only in the correct orientation without any skill or tool.
To remove the grounding clamp (51), a trained person needs to insert a screw driver or equivalent tool in the slit (15) on the same side as the one sided lances (54)/one sided openings (16) and disengage the one sided lances (54) from the one sided openings (16). In other words, the electromechanical connection cannot get disengaged inadvertently.
The electrical terminal (10) therefore provides reliable and proper rounding or earthing, which is crucial for proper functioning of most electrical and electronic circuits.
The electrical terminal (10) is a feed through terminal when there is only present the connecting link (41) with the connecting device (18). When a grounding clamp (51) is provided, the electrical terminal (10) becomes a ground terminal. On providing a plurality of intra-connection plug, the electrical terminal becomes an intra-connection terminal. The electrical terminal thus functions as any or all of the three kinds of terminals separately as well as collectively.
The connection device (18) shown in this embodiment is of a spring clamp type but the connection device can also be of screw clamp type or any other known type.
The punching process is described here for creating the receptacle and illustrating suitability of the design even with uneven partial surface; however, it is not a limitation of the design and the receptacle manufactured from any other process which provides 30% or more flat i.e. burnished area is suitable. Persons skilled in the art can appreciate that processes like fine blanking which can provide almost 80 -80% flat area are expensive but cannot provide better electrical contact, since the effective contact is always in the form of a line contact
Terms “Mounting rail” or “DIN type mounting rail” or “DIN rail” are used interchangeably.
Terms “electromechanical” and “electrical and mechanical” are used interchangeably.


We claim:
1. An Electrical Terminal (10) for feed through, ground and intra-connection, suitable for
fixation on a DIN type mounting rail (11), comprising of an insulating housing (12), a
conducting link (41) with a plurality of connection devices (18), the insulating housing (12)
having a plurality of openings (13) through which conductors can be fixed, characterized in
that:
a. a plurality of plug openings (14) is provided on the insulating housing (12) through
which an intra-connection plug reaches a plurality of sockets (42) in the conducting
link (41);
b. an auto adjusting electromechanical connection between the conducting link (41) and
a grounding clamp (51);
c. the grounding clamp (51) having an eccentrically placed twin male connector (52);
d. a receptacle (43) is provided on the conducting link (41);
e. the grounding clamp (51) assemble-able only in a correct orientation without skill or
tool and removable by a trained person with the application of a tool; and
f. the grounding clamp (51) even if partially inserted during assembly gets properly
fitted when mounted on the DIN type mounting rail (11).
2. The Electrical Terminal (10) as claimed in claim 1 wherein the grounding clamp (51) provides a plurality of independent grounding contacts with the DIN type mounting rail (11).
3. The Electrical Terminal (10) as claimed in claim 1 wherein the auto adjusting electromechanical connection is formed by an engagement of the receptacle (43) on the connecting link (41) with the twin male connector (52) on the grounding clamp (51).
4. The Electrical Terminal (10) as claimed in claim 1, wherein the receptacle (43) has a chamfer (46); and a burr (19) is shaved off for easy and complete entry of the twin male connector (52).
5. The Electrical Terminal (10) as claimed in claim 1 wherein the insulating house (12) at a lower half (31) has a plurality of one-sided openings (16) and a slit (15).

6. The Electrical Terminal (10) as claimed in claim 1, wherein the grounding clamp (51) has four zones – the eccentric twin male connector (52), a plurality of one-sided lances (54), a hinge end (56) and a latch end (57).
7. The Electrical Terminal (10) as claimed in claim 6, wherein the twin male connector (52) in the grounding clamp (51) has a plurality of prongs (55) of an open bifurcation having a convex surface (53) in a distal region of the twin male connector (52).
8. The Electrical Terminal (10) as claimed in claim 7, wherein the convex surface (53) of the twin male connector (52) rests on a burnished area (47) of the receptacle (43) in the connecting link (41) when the plurality of one sided lances (54) on the grounding clamp (51) reach a plurality of one sided openings (16) on the insulating housing (12).
9. The Electrical Terminal (10) as claimed in claim 8, wherein the open bifurcation facilitates the prongs (55) of the twin male connector (52) to bend towards each other minimally and at the same time the convex surface (53) exerts needed pressure on the burnished area (47) when the plurality of one sided lances (54) on the grounding clamp (51) reach the one sided openings (16) on the insulating housing (12).
10. The Electrical Terminal (10) as claimed in claim 8 wherein the grounding clamp (51) in a partially assembled state gets completely assembled and fitted by hooking a leg (58) below an arm (17) of the DIN rail (11) and turning down the electrical terminal (10), causing a second earthing contact (62) to come in contact with the DIN rail (11) early and pushing the grounding clamp (51) towards the connecting link (41), a third earthing contact (63) coming in contact with the DIN rail (11) and further pushing up the grounding clamp (51) towards the connecting link (41) till the one sided lances (54) reach the one sided openings (16).