FORM 2
THE PATENT ACT 1970
&
The Patents Rules, 2003
COMPLETE SPECIFICATION
(See section 10 and rule 13)
1. TITLE OF THE INVENTION:
"Screw-less termination assembly for modular electric devices"
2. APPLICANT:
(a) NAME: Larsen & Toubro Limited
(b) NATIONALITY: Indian Company registered under the
provisions of the Companies Act-1956.
(c) ADDRESS: Larsen & Toubro Limited
Electrical & Automation North Wing, Gate 7, Level 0, Powai Campus, Saki Vihar Road, Mumbai 400 072, INDIA
3. PREAMBLE TO THE DESCRIPTION:

COMPLETE
The following specification particularly describes the invention and the manner in which it is to be performed.

Screw-less termination assembly for modular electric devices
FIELD OF INVENTION
The present invention relates to electrical devices, such as circuit breakers, residual current circuit breakers, residual devices, accessories and contactors especially the modular and din rail mounted installations.
BACKGROUND OF THE INVENTION
The growing use of modular devices in electrical installation has made the distribution systems large with high quantities of these devices to be mounted. With the conventional screw tightening termination the time and efforts required for the installations are increasing.
The regular devices used in general use the screw types of clamping system to make a firm electrical connection between terminal and wire/cable. The required contact pressure is generated by tightening of the screw beyond electrical contact. The installation operation involves loosening the screw to make a cavity for wire or cable, inserting the cable and then tightening the cable. This consumes a lot of time. Also, there is chance of insufficient tightening and loosening over period of time.
There exist already some solutions to this effect but they have some drawbacks as mentioned below. The present invention gives the solution without these drawbacks. The solution involves a spring loaded clamping arrangement (spring clamp) and an actuation mechanism to operate the spring for inserting and releasing the wire.
Prior Methods, Apparatus, Developments and Publications

A lot of prior art exists in area of spring clamp or termination for this type of device. This can be found in publications such as US2713668, US2720634. These types of designs are generally used for the spring clamp. In presented invention the spring clamp is designed suitable to the architecture and space available. Also has additional feature for wire locking.
The other prior arts in the same area have been disclosed in US7510448B shows another such clamping connection which has completely different structure as compared to proposed design.
In this invention the problem of fast installation is solved. A clamp spring 12 rests against connecting conductor 18 and is actuated by a terminal cover part 22 which is pivoted on side 6 of the device. This arrangement provides leverage when user applies an actuating force on Pressure Surface 225. Also part 22 acts to partially cover terminal area and also provides suitable opening for wire insertion from front side.
Though the device allows a leverage for actuation. But here the actuation is suitable for hand operation and it is difficult to use tool for actuation.
Also there seem to be no provision of a test tab or a terminal to connect testing electrode from the front side of the product.
US7491098B1 -{Assignee General Electric Company, Schenectady NY USA).
This invention is also aimed at providing screw less terminal connection for the concerned devices. Here an actuator is required to be pushed by user (using a tool). It acts against a spring 5 directly. Spring is mounted inside terminal compartment 4 which in turn is connected to a current bar 3. The design claims to allow direct insertion of rigid wire through cavity 6. To insert flexible wire actuation of part 2 is required. For removal of both types of wires actuation of part 2 is required.

There is little or no mechanical advantage for user while applying load on actuator 2 as it acts directly on the spring 5. Hence user will experience a high operating force causing fatigue to the user.
This force keeps on increasing with actuator travel as the spring will deflect more and more.
Also there seem to be no provision of a test tab or a terminal to connect testing electrode from the front side of the product.
Objects of the invention
Object of the present invention is to provide a screw-less termination assembly for modular electric devices, which reduces the peak operating force and provides smooth operating force curve.
Another object of the present invention is to provide a screw-less termination assembly for modular electric devices, which enables test tab to be accessible from the front side.
Yet another object of the present invention is to provide a screw-less termination assembly for modular electric devices, which reduces the operating force and also make the force characteristic more flat with respect to actuator motion.
Summary of the invention
Accordingly, the present invention provides a wire clamping assembly for clamping wire against a terminal of a modular electric devices having a housing, a cover and a casing. The assembly having at least one cavity, an actuator, a rotating lever and a clamping spring disposed inside the housing and the cover. The cavity

provides opening for inserting an electric wire therethrough. The actuator with a test terminal and a opening configured on the casing for accessing the actuator for detaching the clamped wires. The rotating lever juxtaposition with the actuator, the rotating lever rotates upon activating the activator. The clamping spring is disposed between the slider and the terminal. The clamping spring enables to detachably secured wire against the terminal and for releasing the wire actuator is rotated manually thereby moving the lever and the slider to operate the clamping spring to release wire therethrough.
Brief description of the drawings
Figure 1 shows a perspective view of a modular electric devices in accordance with the present invention;
Figure 2 shows a exploded and assembly of the modular electric device of figure I;
Figures 3 and 4 shows enlarged views a wire clamping assembly of figure 2: and
Figures 5 and 6 shows an embodiment of an actuator of the modular electric device of figure 2.
Detail 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 embodiments.

The device comprises of a clamping arrangement wherein connecting wire (9) is secured against a terminal (10) by clamp springs (8) which are housed in a wire guide (11)
Actuation and release system having an actuator (4), a rotating Lever
(5) and it may or may not contain a slider (6)
Test terminal (7) mounted in moving actuator for provision of test
Please refer the attached sheet for part numbers and corresponding descriptions
Figure I shows the externals of the device here,
a, b -Heft and right sides of the devices respectively, c,d-> front and back sides of the device respectively e,f -> top and bottom sides of the device respectively
The External casing (1) of the product is made up of two elements, a housing (2) and cover (3). The casing (!) of the device has two cavities (la and lb) (number of cavities equal to number of wires required to be terminated or at-least one) on its top side e. Further, at least one cavity (la and lb), an actuator (4) with a test terminal (7), a rotating lever (5). clamp spring (8) and the terminal (10) are disposed inside the housing (2) and the cover (3) sequentially.
Also there is an actuation cavity (Ic) formed on front side c of the device placed very close to top side e of the device.
Figure 2 shows the internal structure of the device in un-actuated state. The terminal (10) is connected to internal current carrying part of the device. Set of clamp spring (8) is mounted in wire guide (3) and pressure arm (8a) of spring arm locks against a clamping side (10a) of terminal.

The actuator (4) is placed in casing of the product such that its front face is accessible through actuation cavity (1c) in the casing. The actuator (4) has two faces actuation face (4b) and load face (4c). Actuation face is aligned with front side c of the device in un-actuates state. The tool is pressed against the actuation face so as to push or actuate the mechanism. While the load face is disposed inside the casing. The actuation face (4b) also has a test cavity (4a) such that this cavity can be accessed from front side of the device. A test terminal (7) is placed in the actuator (4) just below the actuation face such that it moves along with actuator during its operation. In un-actuated state this test terminal (7) touches a terminal (10) at test contact (10c) and provides an external electrical contact from the test cavity (4a) on the actuator (4) for testing and maintenance purpose. When the actuator (4) is actuated the test terminal (7) loses its contact with the terminal (10). The motion of the actuator (4) is in front-back direction (perpendicular to front and back side of the device). The actuator (4) is guided either by providing supports from housing and cover or a separate component fixed rigidly in casing (not shown here).
The load face (4c) of the actuator (4) acts on an input arm (5a) of the lever (5). such as to rotate the lever (5) around an axis (12) (wherein it is pinned) perpendicular to the sides a and b of the device. The output arm (5b) of the lever
(5) may directly act in the clamp spring (8) but here it is shown to act on the slider
(6) first. The slider (6) is in the L shape with two arms (6a) and (6b). Lever's output arm 5b acts on first arm 6a of the slider where as second arm 6b of the slider acts on clamp spring (8) through a hole provided in terminal (10). The motion of the slider deflects the pressure arm (8a) of the clamp spring (8) away from the terminal (10) thus creating a space for wire insertion. Figure 4 shows the actuated state of the spring and mechanism along with inserted wire.
The lever (5) is located next to the actuator (4) and is also placed in casing (1) of the product such that it is pinned to rotate around an axis (12) which is perpendicular to left side (c) and right side (d) of the device. The motion of lever

(5) is transferred to the clamp spring via slider (6). The slider (6) is allowed to move in only front and back direction (perpendicular to front side and back side).
The reaction between the output arm (5 b) of the lever (5) and the first arm (6a) of slider (6) in un-actuated state is equivalent to clamp load of the spring against terminal or wire. This force is lower in un-actuated state and goes on increasing as spring deflects more and more.
Here the two arms (5a and 5b) of the lever are arranged in such a way that
line of action of force acting between the load face (4c) of the actuator (4) and input arm (5a) of lever (i.e. L1) is closer to lever's rotational axis (12) as compared to line of action of reaction between arm (5b) of lever and arm 6a of slider (i.e. L2) in un-actuated state. Thus during the initial travel of actuator the force required to operate the actuator is more than clamp load of the spring. (As shown in figure 3) But as the actuator slides further the line of action of force acting between the load face (4c) of the actuator (4) and input arm (5a) of lever moves away progressively from lever's axis of rotation at the same time line of action of reaction between arm b of lever and arm a of slider moves closer to lever's axis of rotation. (As shown in figure
5) - This gradually increases the total mechanical advantage available at the actuation face (4b) of the actuator reducing the actuation force as compared to increasing clamp load. The result of this arrangement is smooth force curve (lesser rise) with respect to travel of actuator as clamp spring force will keep on increasing.
With right lengths of lever arms, the peak value of actuation force can be effectively reduced as compared to peak value of clamp load.

The terminal has clamping side (10a) against which the clamp spring (8) locks the inserted wire. The clamping side is provided with hole (10b) through which second slider arm (6b) operates on the pressure arm (8a) of the spring. It also is provided with sharp locking protrusion (10d) which helps in better locking of the wire, (Refer fig 2 and 4)
As discussed earlier the clamp spring (8) has a pressure arm (8a) which is responsible for giving locking pressure on the wire (9) against terminal. The other side of the clamp spring (8) is used to fix the clamp spring in wire guide (II). The number of clamp springs is equal to numbers of wires required to be terminated.
The wire guide designed to guide the wire during insertion process. The wire guide has guide cavities (IIa) which are extended up to clamping arm of the spring. The guide cavities are locates in wire-guide such that they get aligned with wire cavities 1a and 1b provided in casing so that there is an extended and better guide for wires during insertion.
This also provides support to wire if the portion of the wire external to product is deflected laterally. The wire guide is mounted in casing rigidly. The central wall (11b) and outer walls (11e) create separates insertion spaces of two wires and provides an addition guide.
During the insertion of rigid wire the wire itself deflects the clamping arm of the clamp spring and does not need an actuation for insertion whereas insertion of flexible wire needs the prior actuation.
Both types of wire require actuation by actuator for their removal.
With little modification following variations are possible:

- Instead of plurality of clamp spring there can be a single clamp spring component having plurality of arms acting on the spring clamp independently.
- The explained design can have provisions for number of wires to be inserted. Jn that case the number of clamp spring or clamp spring arms will be equal to number of wires to be inserted.
There can be another variation of the actuator design Referring to figure 5 and 6. load face (4c) of actuator is curved with center of the curve designed in such a way that better control over distances of L1 and L2 from lever axis of rotation is obtained. This further helps in reduces peak actuation force required by user.
The embodiments were chosen and described in order to best explain the principles of the present invention and its practical application, 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 omission and substitutions of equivalents are contemplated as circumstance may suggest or render expedient. but such are intended to cover the application or implementation without departing from the spirit or scope of the present invention.

We Claim:
1. A wire clamping assembly for clamping wire against a terminal of a
modular electric devices having a housing, a cover and a casing, the assembly
comprising:
at least one cavity configured on the casing for inserting an electric wire therethrough;
an actuator with a test terminal disposed between the housing and the cover and a opening configured on the casing for accessing the actuator for detaching the clamped wires;
a rotating lever disposed between the housing and the cover and juxtaposition with the actuator, the rotating lever rotates upon activating the actuator; and
a clamping spring disposed between the housing and the cover and between the slider and the terminal, the clamping spring enables to detachably secured wire against the terminal and for releasing the wire actuator is rotated manually thereby moving the lever and the slider to operate the clamping spring to release wire therethrough.
2. The wire clamping assembly as claimed claim 1, further comprising a slider reciprocally disposed between the rotating lever and the clamping spring, the slider reciprocates on rotation of the rotating lever.
3. The wire clamping assembly as claimed claim 1, wherein the lever is pinned between spring and actuator to rotate there around.
4. The wire clamping assembly as claimed claim 1, wherein the actuator has straight load face of contact with the lever.

5. The wire clamping assembly as claimed claim 1, wherein the actuator has curved load face of contact with the lever.