FORM 2
THE PATENT ACT 1970
&
The Patents Rules, 2003
COMPLETE SPECIFICATION (See section 10 and rule 13)
1. TITLE OF THE INVENTION:
Gear Linkage Mechanism for Switching 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,
L&T House, Ballard Estate, P. 0. Box: 278, Mumbai 400 001, India
3. PREAMBLE TO THE DESCRIPTION:
COMPLETE
The following specification particularly describes the invention and the manner in which it is to be performed.

Gear Linkage Mechanism for Switching Devices
Field of the invention
The present invention relates to a rotary mechanism for switching devices and more particularly, to a top mounted gear linkage mechanism for switching devices for example, low voltage switchgear products.
Background of the invention
Electrical switching apparatus such as a switch disconnector provides isolation and is capable of making, carrying and breaking currents under normal circuit conditions based on specified operating overload conditions for specific time. These apparatuses also operate under specified abnormal circuit conditions such as short circuit for a specified time. These are suitable for diverse applications in motor control centers, switchboards and as main switches in various equipments and machines. These switches are ideal for withstanding higher short circuit currents for short time duration.
In general, the electrical switching apparatus comprises a contact system and rotary mechanism to actuate the contact system. The contact system consists of a terminal and a rotor assembly. The rotor assembly includes a rotor, a moving contact, a magnetic cladding and a leaf spring. Since, the electrical switching apparatus is installed into a Distribution Box (DB) panel or a switch board panel, space is a constraint. Hence, this combination should be accommodated in the most optimum space possible. The rotary mechanism mounted on left or right side of the compact system tends to increase the overall size which is against the panel requirement.

The electrical switching devices available in the art are manual and hence operated solely by means of directly applied manual energy. As a result, the speed and force of the operation are dependent upon the action of the operator.
Accordingly, there is a need to provide a mechanism for switching devices that overcomes the problems in the prior art.
Object of the present invention
An object of the present invention is to provide a manually independent actuation of a contact system.
An object of the present invention is to reduce the space utilization in a distribution box panel.
Summary of the invention
Accordingly, the present invention provides a gear linkage mechanism for a switching device. The gear linkage mechanism comprises an enclosure, an arm, a shaft connector, a first gear, a second gear, a coupler and at least two linkages. The enclosure is mounted on a housing of a contact system. The enclosure supports the arm thereon. The arm includes a spring and a first pin. The spring is coiled on the arm with an end locked in the first pin. The arm moves to generate spring energy when an operator operates a switch of the switching device (200) to DEAD CENTRE position.
The shaft connector is positioned on the arm. The shaft connector (30) includes a second pin attached thereto. The shaft connector is adapted to rotate at DEAD

CENTRE position by utilizing spring energy thereby rotating the second pin. The second pin engages in a slot of the first gear at DEAD CENTRE position.
The first gear (40) is positioned horizontally on the enclosure. The gear includes a first slot and a second slot. The first slot connects the first gear to the shaft connector. The second slot is capable engaging the second pin at DEAD CENTRE position. The first gear is capable of being driven by the shaft connector via the second pin. The first gear drives the second gear post DEAD CENTRE position.
The second gear is positioned vertically on the enclosure. The second gear includes a third slot and a fourth slot for coupling to a rotor of the contact system. The second gear is coupled to the rotor of the contact system by the coupler. The coupler is connected to the second gear by the at least two linkages that converts vertical motion into horizontal motion. The at least two linkages includes a spacer positioned there between.
During an operation of the switching device from OFF position to ON position, the operator operates the switch till DEAD CENTRE position to cause movement of the arm to generate spring energy. The spring energy causes rotation of the shaft connector to drive the first gear via the second pin. The first gear post DEAD CENTRE position drives the second gear to drive the coupler that in turn drives the contact system rotor thereby causing the switching device to occupy ON position.
Brief description of the drawings
The objectives and advantages of the present invention will become apparent from the following description read in accordance with the accompanying drawings wherein.

Figures 1-2 show a switching device having a contact system and a top mounted gear linkage mechanism, in accordance with the present invention;
Figure 3 shows a top perspective view of the switching device of figure 1;
Figure 4 shows a side perspective view of the switching device of figure 1;
Figure 5 shows a side perspective view of the contact system and the top mounted gear linkage mechanism of figure 1 in OFF position without the enclosure;
Figure 6 shows a side perspective view of the contact system and the top mounted gear linkage mechanism of figure 1 in DEAD CENTER position without the
enclosure;
Figure 7 shows a side perspective view of the contact system and the top mounted gear linkage mechanism of figure 1 in ON position without the enclosure;
Figure 8 shows a perspective view of the top mounted gear linkage mechanism of figure 1 in OFF position;
Figure 9 shows a perspective view of the top mounted gear linkage mechanism of figure 1 in DEAD CENTRE position;
Figure 10 shows a perspective view of the top mounted gear linkage mechanism of figure 1 in ON position; and
Figures 11-13 show respective perspective views of a first gear, a second gear and a coupler of the gear linkage mechanism of figure 1.

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 a gear linkage mechanism for a switching device. The gear linkage mechanism is mounted on top of a contact system of the switching device to drive a rotor of a contact system in a manually independent operation. The gear linkage mechanism of the present invention is compact thereby utilizes lesser space in a distribution box panel.
The present invention is illustrated with reference to the accompanying drawings, throughout which reference numbers indicate corresponding parts in the various
figures.
Referring now to figures 1-10, there is shown a gear linkage mechanism (100) for a switching device (200), in accordance with the present invention. Specifically, the switching device (200) is a multi-pole switching device for example, a 3-pole switch disconnector having a pole width of 34.5 mm, a switch width of 67 mm, height of 114 mm and depth of 88.5 mm. However, it is understood that the dimensions of the switching device (200) may vary in other alternative embodiments of the present invention.
The switching device (200) comprises a modular contact system (180) and the gear linkage mechanism (100). The contact system (180) (refer to figures 5-7) includes a housing (160). The housing (160) includes a terminal (110), a rotor (120), amoving contact (130), a magnetic cladding (140) and a leaf spring (150). The contact

system (180) is actuated by the gear linkage mechanism (100). The gear linkage mechanism (100) is mounted on the housing (160) of the contact system (180). The gear linkage mechanism (100) (refer to figures 8-10) comprises an enclosure (10), an arm (20), a shaft connector (30), a first gear (40), a second gear (50), a coupler (60) and at least two linkages (70). The rotary mechanism (100) is assembled by using any suitable means known in the art.
The enclosure (10) of the gear linkage mechanism (100) is mounted on the housing (110) of the contact system (180) by means of screws placed at a position on the gear linkage mechanism (100) indicated by reference numeral 1 (shown in figures 8-10) and is inserted into the housing (160) of the contact system (180) as well. The arm (20) is supported on the enclosure (10). The arm (20) includes a spring (18) and a first pin (16). The spring (18) is coiled on the arm (20) such that an end (not numbered) of the spring (18) is locked into the first pin (16) and another end (not shown) of the spring (18) is connected to the second gear (50). The spring (18) remains in a pre-charged condition during OFF position of the switching device (200). The arm (20) moves when an operator operates a switch (not shown) of the switching device (200) till DEAD CENTRE position (refer to figures 6 and 9) during an operation of the switching device (200) from OFF position (refer to figures 5 and 8) to ON position (refer to figures 7 and 10). At the DEAD CENTRE position, the spring (18) is compressed the most due to the movement of the arm (20) resulting in generation of energy that is stored in the spring (18).After compression, the spring (18) drives the mechanism through the energy stored therein.
The arm (20) includes the shaft connector (30) positioned thereon. The shaft connector (30) includes a second pin (25) attached thereto. The shaft connector (30) is adapted to rotate in response to arm movement by utilizing spring energy. The

rotation of the shaft connector (30) in turn rotates the second pin (25) for engaging and driving the first gear (40).
The first gear (40) is positioned horizontally on the enclosure (10) and is capable of
being driven by the shaft connector (30) via the second pin (25). The first gear (40)
includes a first slot (42) and a second slot (44) (refer to figure 11). The first slot (42) is for attachment with the connector shaft (30). The second slot (44) of the first gear (40) is for engaging the second pin (25) therein. The second slot (44) in the first gear (40) is configured to receive the second pin (44) only at DEAD CENTRE position. The first gear (40) drives the rotation of the second gear (50).
The second gear (50) is positioned vertically on the enclosure (10). The second gear (50) includes a third slot (52) and a fourth slot (54) (refer to figure 12) for coupling to the rotor (120) of the contact system (180) through the coupler (60) (refer to figure 13). The coupler (60) is used for coupling the gear linkage mechanism (100) to the rotor (120) of the contact system (180) so that the energy from the gear linkage mechanism is transferred to the contact system (180). The coupler (60) is rigidly clinched onto the rotor (120). The coupler (60) is connected to the second gear (50) through the at least two linkages (70). The at least two linkages (70) includes a spacer (65) positioned there between. The spacer (65) is used so that the first gear (40) is not in a direct contact with the enclosure (10) and hence reduces friction. The at least two linkages (70) convert vertical motion of the second gear (50) into horizontal motion thereby rotating the rotor (120) of the contact system (180).
During the operation of the switching device (200) from OFF position to ON '
position, an operator operates a switch (not shown) from OFF position till DEAD CENTRE position. At DEAD CENTRE position, the arm (20) moves to generate

spring energy. The spring energy causes rotation of the shaft connector (30) that causes the second pin (25) to engage with the second slot (44) of the first gear (40). The second slot (44) in the first gear (40) is configured to receive the second pin (44) only at DEAD CENTRE position so that the rotor (120) of the contact system (180) moves only after the DEAD CENTER position. Thus the shaft connector (30) rotates the first gear (40) via the second pin (25) at the DEAD CENTRE position.
Post DEAD CENTRE position the first gear (40) drives the rotation of the second gear (50). The second gear (50) drives the coupler (60). The coupler (60) in turns drives the rotor (130) of the contact system (180) thereby turning the switch ON and causing the switching device (200) to occupy ON position.
Advantages of the present invention
1. The gear linkage mechanism (100) drives the contact system (180) by converting rotary motion in one direction to rotary motion in the direction perpendicular to the first direction of motion by using the gears (40, 50) and linkages (70) with higher efficiency.
2. By using linkages (70) for transmission of energy from vertical motion at the shaft connector (30) to horizontal motion of the rotor (120), complexity of the gear linkage mechanism (100) has been reduced resulting in less assembly time.
3. The slotted first gear (40) coupled indirectly to the rotor (120) of the contact system (180) through the linkages (70) and the coupler (60) helps to achieve intentional transmission delay and manual independency.
4. The gear linkage mechanism (100) is a compact mechanism mounted on top (housing (160)) of the contact system (180) to achieve better performance.

5. The gear linkage mechanism (100) is compact due to the use of bare minimum number of components and has also reduced the size of the switch due to the use of linkages (70).
The foregoing objects of the invention are accomplished and the problems and shortcomings associated with prior art techniques and approaches are overcome by the present invention described in the present embodiment. Detailed descriptions of the preferred embodiment are provided herein; however, it is to be understood that the present invention may be embodied in various forms. Therefore, specific details disclosed herein are not to be interpreted as limiting, but rather as a basis for the claims and as a representative basis for teaching one skilled in the art to employ the present invention in virtually any appropriately detailed system, structure, or matter. The embodiments of the invention as described above and the methods disclosed herein will suggest further modification and alterations to those skilled in the art. Such further modifications and alterations may be made without departing from the spirit and scope of the invention.

We Claim:
1. A gear linkage mechanism (100) for a switching device (200), the gear linkage mechanism (100) comprising:
an enclosure (10) mounted on a housing (110) of a contact system (180); an arm (20) supported on the enclosure (10), the arm (20) having a spring (18) coiled thereon and a first pin (16) locking an end of the spring (18) therein, the arm (20) moves to generate spring energy when an operator operates a switch of the switching device (200) to DEAD CENTRE position;
a shaft connector (30) positioned on the arm (20), the shaft connector (30) having a second pin (25) attached thereto, the shaft connector (30) adapted to rotate utilizing spring energy thereby rotating the second pin (25);
a first gear (40) positioned horizontally on the enclosure (10), the first gear (40) having a second slot (44) for engaging the second pin (25), the first gear (40) capable of being driven by the shaft connector (30) via the second pin (25);
a second gear (50) positioned vertically on the enclosure, the second gear (50) capable of being driven by the first gear (40) post DEAD CENTRE position;
a coupler (60) coupling the second (50) to a rotor (120) of the contact system (180); and
at least two linkages (70) having a spacer (65) positioned therebetween, the at least two linkages (70) connecting the coupler (60) to the second gear (50) thereby converting vertical motion into horizontal motion,
wherein, during an operation of the switching device (200) from OFF position to ON position, the operator operates the switch till DEAD CENTRE position to cause movement of the arm (20) to generate spring energy, the spring energy causes rotation of the shaft connector (30) to drive the first gear (40) via the second pin (25), the first gear (40) post DEAD CENTRE position drives the second

gear (50) to drive the coupler (60) that in turn drives the rotor (130) of the contact system (180) thereby causing the switching device (200) to occupy ON position.
2. The gear linkage mechanism (100) as claimed in claiml wherein, the second slot (44) of the first gear (40) receives the second pin (25) at the DEAD CENTRE position.
3. The gear linkage mechanism (100) as claimed in claiml wherein, the first gear (40) having a first slot (42) for connecting to the shaft connector (30).
4. The gear linkage mechanism (100) as claimed in claiml wherein, the rotor (120) of the contact system (180) rotates after the DEAD CENTRE position. .