FORM2
THE PATENT ACT 1970 &
THE PATENTS RULES, 2003
COMPLETE SPECIFICATION
(section 10 and rule 13)
1. TITLE OF THE INVENTION:
"Spring clamp electrical terminal for quick installation of an electrical device"
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, Murnbai 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.

Spring clamp electrical terminal for quick installation of an electrical device Field of the invention
The invention relates to electrical switching devices and more particularly to a spring clamp electrical terminal adapted for quick installation of an electrical device.
Background of the invention
An electrical switching device connected in electrical installation generally includes an electrical terminal means or connecting means to establish an electrically conductive connection between the electrical conductor and the electrical device facilitated by a contact element of the metal part of the device and a mating contact element of the clamping spring. It is well known to use screw type of terminals for installation of the electrical device. In these type terminals, lot of time and efforts are required in connecting the terminals to the external conductors.
There are attempts seen in the art for using spring clamp type of electrical terminals to overcome the disadvantages of the screw type terminals. These electrical terminals utilize clamping springs for connecting the clamping spring to the metal part. The clamping springs normally have two types of legs, namely a clamping leg and a contact leg. However, the spring clamp type electrical terminals in the art normally have a terminal spring that is of U-shape. The U-shape shaped terminal springs essentially need the electrical conductor to be drawn against the conductor rail by the clamping legs. Also, the contact legs of these clamping springs are parallel to a direction of insertion of the electrical conductor to be connected.
Therefore, there exists a need to provide a spring clamp electrical terminal that overcomes all the drawbacks of the existing art.
Objects of the invention
An object of the present invention is to provide a spring clamp electrical terminal that enables simple but secure fixing of the clamping spring with the electrical conductor

facilitating a quick connection during installation and a quick removal during maintenance.
One more object of the present invention is to provide a spring clamp electrical terminal that is easy to manufacture, assemble & function.
Summary of the invention
Accordingly the invention provides a spring clamp electrical terminal assembly adapted to be positioned within a hollow body structure of an electrical switching device having a conventional terminal assembly mounted on a first side and the spring clamp terminal assembly mounted on a second side. The spring clamp terminal assembly comprises a clamping spring positioned on a metal part. The clamping spring is having an upward sloping portion and a downward vertical straight portion. The clamping spring is having a pair of contact legs and a pair of side clamping legs, The contact legs define a recess therein to facilitate insertion of an electrical conductor. The contact legs position substantially perpendicular to a direction of insertion of the electrical conductor. The spring is having a funnel shape that assists in insertion of the conductor within the recess.
The spring clamp terminal assembly includes an actuating lever that is having an actuating arm and a working arm interlinked through a pin mounted thereon. The actuating arm and the working arm form an obtuse angle there between that is in the range of about 145° to 175°. The actuating lever is having a slanted pressing tip that communicates with an actuating arm of the clamping spring. The actuating arm controls a downward movement of the spring between an unlatched position and a latched position to facilitate insertion of the electrical conductor within the recess.
Brief description of the Drawings:
Invention is described with reference to figures of the accompanying wherein:

Figure 1(a) is a front view of a miniature circuit breaker constructed in accordance with the present invention having a conventional terminal assembly on one side and a spring clamp terminal assembly on other side;
Figure 1(b) is a top view of the miniature circuit breaker of Figure 1 (a);
Figure 1(c) is a side view of the miniature circuit breaker of Figure 1(a);
Figure 2 is a detailed front view of a miniature circuit breaker of Figure 1 (a) having the conventional terminal assembly on one side and the spring clamp terminal assembly on other side;
Figure 3 is a detailed front view of a miniature circuit breaker of Figure 2 showing the spring clamp terminal assembly in an undamped position;
Figure 4 is a detailed front view of the miniature circuit breaker of Figure 2 showing the spring clamp terminal assembly in a clamped position;
Figure 5 is a detailed perspective view of the miniature circuit breaker of Figure 2 showing the spring clamp terminal assembly in the undamped position;
Figure 6(a) is a front view of the spring clamp terminal assembly of Figure 2 in the clamped position;
Figure 6(b) is a side view of the spring clamp terminal assembly of figure 6(a); and
Figure 6(c) is an isometric view of the spring clamp terminal assembly of figure 6(a).
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 embodiments.

For the better understanding of this invention, reference would now be made to the embodiment illustrated in greater depth in the accompanying figures and description herein below, further, in the following figures, the same reference numerals are used to identify the same components in various views/figures.
Referring to Figures 1(a), 1(b), 1(c) and 2, an electrical device 100 having a spring clamp electrical terminal assembly in accordance with the present invention is shown. The electrical device 100 is a miniature circuit breaker in this one particular embodiment that is having an insulating housing 1 and an insulating cover 2. The miniature circuit breaker is adapted to be installed using a DIN clip 3 on the DIN rail mounted on the panel. The miniature circuit breaker includes a knob 4. The miniature circuit breaker is configured to have electrical connections that are made on both sides, namely an incoming terminal and an outgoing terminal, to have an electrical supply. The circuit breaker 100 is having a first end and a second end. The first end of the circuit breaker 100 includes a conventional screw type terminal assembly 5, preferably located on the left side of the circuit breaker in this one particular embodiment. The second end of the circuit breaker includes a spring clamp terminal assembly 5A, preferably located on the right side of the circuit breaker in this one particular embodiment. However, it is understood that the spring clamp terminal assembly 5A may be positioned on both sides of the circuit breaker 100 in other alternative embodiments of the present invention. The spring clamp terminal assembly 5A includes a pair of contact legs 7, a base 8 and a clamping spring 9 adapted to be mounted within a hollow body structure defined within the housing 1. The contact legs 7 of the split ring are adapted to clamp the conductor by actuator operation within no time. A box clamp 10 is positioned in the proximity to the conventional screw type terminal assembly 5 on the left side of the circuit breaker 100 in this one particular embodiment. According to another embodiment of the spring clamp electrical terminal assembly 5A of the present invention, the conductor insertion is split into two to have better clamping force for both the conductors. This makes the spring clamp electrical terminal 5A to be used for high current ratings up to 40A by suitably dividing the total cross-section of the electrical conductor into two halves.

Referring to Figures 3-5, a detailed view of the miniature circuit breaker 100 is shown wherein the clamping spring terminal assembly 5A is having a first latched position and a second unlatched position. The clamping spring 9 is adapted to be mounted over a current bar/terminal conductor, in particular a metal part 11 that is configured to carry a current. The clamping legs 12 of the contact spring 9 are bent opposite to the mounting surface to form a curved portion near to the said one end. The clamping spring 9 is having an upward sloping portion after the curved portion and a downward vertical straight portion after the sloping portion that makes the spring to have a 'q' shape in this one particular embodiment.
As shown in Figures 6(a), 6(b) and 6(c), the clamping spring terminal assembly 5A is having a first end having a mounting surface that is at least partially split up along a centre portion to define a pair of side clamping legs 12. The pair of side clamping legs 12 are arranged essentially perpendicular to an insertion direction of the electrical conductor in this one particular embodiment. The contact legs 12 define a recess adapted to facilitate insertion of the electrical conductor to be connected. The contact legs 7 are split along a centre portion for insertion of a wire. The contact spring is having an actuating arm 13 adapted to communicate with an actuating lever 6.
The actuating lever 6 is supported in the hollow body structure of the enclosure 1. The actuating lever 6 is having an actuating arm 14 and a working arm 15 that are interlinked through a pin 16. The actuating arm 14 is positioned above the pin 16 and the working arm 15 is positioned below the pin 16. The actuating lever 6 is having an obtuse angular shape such that the angle between the actuating arm and the working arm is in the range of about 145° to 175° in this one particular embodiment. The said angle is configured to face towards the circuit breaker 100.
The lever 6 is adapted to be moved by the actuating arm 14 towards the body of the switchboard thereby causing the working arm 15 of the actuating lever 6 to move towards the sloping spring 9 thereby causing pushing down of the sloping spring 9 for downward movement of the vertical straight portion of the spring 9. The working arm 15 is having a lower end that includes a slanted pressing tip that communicates with the actuating arm 13 of the spring 9. In this position, the electrical conductor positioned on the surface below the vertical straight portion of the spring 9 enters into

the recess defined by the contact legs 7 and hold the conductor firmly by the spring action therein. However, it is understood here that the electrical connection can be achieved by directly inserting the conductor in the recess of the clamping spring 9 for solid conductors. A funnel shape 17 is given at a tip portion of the spring 9 to assist insertion of the conductor into the split space formed within the contact legs 7.
The insulating housing 1 includes an actuating opening for insertion of an actuating tool. A slot is made on the actuating arm 14 of the actuating lever 6 that is aligned in the direction of the spring force of the clamping leg 12 to enable the tip of the actuating tool to act on the slot of the actuating arm 14 for opening the clamping spring 9. However, it is understood that the actuating opening for insertion of an actuating tool results the spring clamp electrical terminal to be used for fine wire flexible conductors in which opening of the clamping spring 9 by inserting the electrical conductor is not possible. Moreover, an already clamped electrical conductor can be released again from the clamping site by opening the clamping spring 9 using the actuating tool.
In an alternative embodiment of the present invention, a second mounting section is punched out of the current bar opposite to a first punched area to better fix the clamping spring 9 on the metal part 11 preferably on the end of the recess opposite the mounting section. In this alternative embodiment, the contact legs 7 are placed over two mounting sections of the current bar. However, it is understood that the distance between the two mounting sections is chosen corresponding to the length of the recess in the clamping spring 9 so that the clamping spring 9 is fixed on the metal part 11 by the two mounting sections which have been inserted through the recess in the clamping spring 9. In this one alternative embodiment, the metal part 11 is made as a flat current bar that extends essentially parallel to the direction of insertion of the electrical conductor to be connected. It is understood here that the metal part 11 runs essentially perpendicular to the insertion direction of the conductor to be connected. This primary extension of the metal part 11 may be used for factory calibration & testing thereby eliminating the need for extra metal terminal.
In yet another embodiment of the present invention, the mounting section of the clamping spring 9 is bent down such that the mounting section, together with the end

of the clamping leg 12 of the clamping spring 9, forms an inlet funnel for the electrical conductor to be connected. The inlet funnel thus automatically positions the tip of an electrical conductor accurately that needs to be pushed through the conductor inlet opening into the insulating housing 1 to enable simple and exact connection of the electrical conductor to the spring clamp electrical terminal 5 A.
In further alternative embodiment of the present invention, a V-shaped partially split spring 9 is having the upwardly sloping portion and the vertically straight portion that may be utilized and rigidly fixed to the current bar to get the same result of the spring clamp as described herein as illustrated in Figures 3 to 6. In this one alternative embodiment, the V-shaped spring 9 is bent to an angle less than 90°at one end sloping upwardly and fastened rigidly to the current conductor of the switch thereby keeping the vertically straight portion to have two contact leg formed therein. In this alternative embodiment, the working arm 15 of actuating lever 6 presses on the sloping portion of spring 9 to cause the downward movement of the spring 9.
Advantages of the present invention
1. The spring clamp electrical terminal assembly 5A advantageously facilitates connection of the electrical conductor on the electrical switching device 100.
2. The spring clamp electrical terminal assembly 5A advantageously facilitates removal of the electrical conductor on the electrical switching device 100.
3. The spring clamp electrical terminal assembly 5A advantageously makes installation and removal operation of the electrical conductor simple and robust.
4. The spring clamp electrical terminal assembly 5A is easy to manufacture, assemble and function.
5. The spring clamp electrical terminal assembly 5A is advantageously facilitates splitting of the conductor insertion into two to have better clamping force. This makes the electrical switching devices to be used for high current ratings up to 40 A by suitably dividing the cross section of the electrical conductor into two parts.
6. The spring clamp electrical terminal assembly 5A is usable for fine wire flexible conductors in which opening of the clamping spring 9 by inserting the electrical conductor is not possible.

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, 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 spring clamp electrical terminal assembly positioned within a hollow body
structure of an electrical switching device having a conventional terminal assembly
mounted on a first side and the spring clamp terminal assembly mounted on a second
side, characterized in that, the spring clamp terminal assembly comprising:
a clamping spring positioning on a metal part, the clamping spring having an upward sloping portion and a downward vertical straight portion, the clamping spring having a pair of contact legs and a pair of side clamping legs, the contact legs defining a recess therein for facilitating insertion of an electrical conductor; and
an actuating lever having an actuating arm and a working arm interlinked through a pin mounted thereon, the actuating arm and the working arm forming an obtuse angle therebetween, the actuating lever having a slanted pressing tip communicating with an actuating arm of the clamping spring, the actuating arm controlling a downward movement of the spring between an unlatched position and a latched position for inserting the electrical conductor within the recess.
2. The spring clamp terminal assembly as claimed in claim 1, wherein the contact legs position substantially perpendicular to a direction of insertion of the electrical conductor.
3. The spring clamp terminal assembly as claimed in claim 1, wherein the spring is having a funnel shape that assists in insertion of the conductor within the recess.
4. The spring clamp terminal assembly as claimed in claim 1, wherein the said obtuse angle between the actuating arm and the working arm is in the range of about 145° to 175°.
5. The spring clamp terminal assembly as claimed in claim 1, wherein the spring isof'q'shape.
6. The spring clamp terminal assembly as claimed in claim 1, wherein the spring is of 'V shape.

7. The spring clamp terminal assembly as claimed in claim 1, wherein the clamping spring includes a second mounting section that is punched out of the electrical conductor to firmly fix the clamping spring on the metal part.