F O R M 2

THE PATENTS ACT, 1970
(39 of 1970)
&
The Patents Rules, 2003
COMPLETE SPECIFICATION
(See section 10; rule 13)

1. Title of the invention: TERMINATION PITCH ADJUSTABLE TRANSMISSION SHAFT ASSEMBLY FOR MOVING CONTACT IN LV SWITCHGEAR PRODUCTS

2. Applicant(s):

(a) NAME : LARSEN & TOUBRO LIMITED
(b) NATIONALITY : An Indian Company
(c) ADDRESS : L & T House, Ballard Estate, Mumbai 400 001, State
of Maharashtra, India

3. PREAMBLE TO THE DESCRIPTION

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

FIELD OF THE NVENTION

The present invention relates to a transmission shaft for low voltage circuit breakers. More particularly, the invention is concerned about a termination pitch adjustable transmission shaft assembly for moving contact in lv switchgear products. The assembly reveals that how different electrical pole with different pole pitch are positively interlocked with each other to form a transmission shaft so that all the poles would be closed and opened simultaneously.

BACKGROUND OF THE INVENTION

In conventional system, poles are connected together by means of single rigid rod, which increases complexity in housing cover design also it is difficult to maintain adequate creepage distance and to give positive barriers to restrict internal gases which may cause internal flashover. In this conventional system it is difficult to assemble number of poles and carry out maintenance of specific electrical pole.

US6960731B2 discloses a separate actuating module is provided to couple adjacent poles. The additional coupler has Male features on end surfaces and female feature on contact supporting module; Because of such construction coupling between adjacent contacts supporting module (pole) is not possible without actuating module. So there is restriction on adjustability of termination pitch in switch. And switch can’t be operated without actuating module. Also this construction use 3 male features on actuating module and 3 female features on contact supporting module responsible for interlocking of poles. But because of manufacturing tolerances and clearances practically only one feature will engage to transmit torque between poles. So entire load will be taken by single feature, which may cause extra stress on the component, which will lead to breakage of that feature costing the basic functionality of actuating module.

US 5479143 discloses a adjacent contact system module is coupled together through a metal coupler. Provision of metal coupler can cause a potential danger of short-circuiting if not shielded/isolated properly during assembly. Being a critical component in torque transmission; needs dimensional accuracy; achieving it in metallic component will lead to increase in manufacturing cost.

US 6084489 uses Elongated pins to connect moving contact of all poles to form a drive shaft to make switch ON and OFF. A conducting bar or pin running throughout the entire length between various poles, may cause short-circuiting which is very dangerous.

Thus, there is a need to overcome the problems of the prior art. therefore, present inventors have developed a termination pitch adjustable transmission shaft assembly for moving contact in lv switchgear products to provide ease of asssembling, ease of maintenance, choice to connect number of poles, isolating load from supply, making and breaking all the poles simultaneously to avoid any damage to the load and reducing tooling cost.

OBJECTS OF THE INVENTION

An object of the present invention is to overcome the problems/disadvantages of the prior art.

Another object of the present invention is to provide a termination pitch adjustable transmission shaft assembly for moving contact in lv switchgear products.

These and advantages of the present invention will become readily apparent from the following detailed description taken in conjunction with the accompanying drawings.

SUMMARY OF THE INVENTION

According to one aspect of the present invention there is provided a termination pitch adjustable transmission shaft assembly for moving contact in lv switchgear products, said assembly comprising:
a cassette means;
plurality of rotor means ;
coupler means;
wherein said rotor means comprising a male feature and a female feature adapted to be operatively engaged with an identical or substantially identical female feature and male feature of another rotor means respectively so as to form transmission shaft means of a switch;
wherein said coupler means comprising a male feature and a female feature adapted to be operatively engaged with proximate pole means such that termination pitch adjustable transmission shaft being formed ensuring wide range of termination pitch.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS

Other features as well as the advantages of the invention will be clear from the following description.
In the appended drawings:
Figure 1 illustrates a Rotor Assembly
Figure 2 illustrates Side A of rotor
Figure 3 illustrates Side B of rotor
Figure 4 illustrates Male-female feature of rotor
Figure 5 illustrates Interlocking of rotor forming a transmission shaft
Figure 6 illustrates how adjacent pole gets engage with each other
Figure 7 illustrates adjacent pole in assembles condition with coupler

DETAILED DESCRIPTION OF THE ACCOMPANYING DRAWINGS

In the following detailed description, reference is made to the accompanying drawings that form a part hereof, and illustrate the best mode presently contemplated for carrying out the invention. Further functioning of the mechanism has been discussed below to describe the way the mechanism operates. However, such description should not be considered as any limitation of scope of the present unit. The structure thus conceived is susceptible of numerous modifications and variations, all the details may furthermore be replaced with elements having technical equivalence. In practice the materials and dimensions may be any according to the requirements, which will still be comprised within its true spirit.

According to the invention there is provided a termination pitch adjustable transmission shaft assembly for moving contact in lv switchgear products. Switch is combination of mechanism and number of poles connected side by side. One mechanism drives all the poles and therefore all poles are mechanically interlocked with each other for simultaneous ON/OFF operation. All poles are interlocked with each other through single integrated rotor of each cassette. Rotors (1) from adjacent pole engage with each other through Male (5) and Female feature (6) as shown in figure1. Male and female feature of side A as shown in figure 2 is 180 degree opposite to Male and Female feature of side B as shown in figure 3.

Figure 4 shows, after keeping poles side by side for assembly Male feature of one rotor comes in front of female feature of another rotor and vice versa. So Male, female feature of one rotor assembly engages with Female, male feature of adjacent rotor assembly respectively shown in figure 5 to form a transmission shaft of a switch, which can be drive through mechanism having identical male and female feature. As rotor (1) is a single mould component there is no radial play between Male and female feature of both end surfaces (Side A (7) and Side B (8)) of same rotor (1).

When same switch is to be used for application where different termination pitch is needed to terminate different sizes of cables/links, then coupler is placed in between the two poles which is having identical male and female features same as Side A (7) and Side B (8) of rotor (1) as shown in Figure6. This forms a transmission shaft as shown in figure7. This transmission shaft will be driven by Mechanism having identical male (5) and female features (6).

So the switch can be operated with and without coupler (13), ensuring wide range of termination pitch. This gives benefit to customer to offer different current rating from same cassette.

The Male (5) and Female features (6) are designed to have multiple driving surfaces and higher strength.

The surfaces are shown in figure 2 and figure 3. The features are identical in rotor and coupler. In assembled condition, surfaces 9A and 10A makes contact with surfaces 9B and 10B respectively. And surfaces 11A and 12A makes contact with surfaces 12A and 12B respectively. So during motion transmission, when transmission shaft is rotated in anticlockwise direction the surfaces 9A and 10A drives surfaces 9B and 10B respectively resulting into ON operation of switch. And when transmission shaft is rotated in clockwise direction the surfaces 11A and 12A drives surfaces 11B and 12B respectively resulting into OFF operation of switch.

As minimum 2 surfaces are provided to drive the transmission shaft, even after manufacturing tolerances and clearances at least one surface will come in contact with the other. So positive interlocking between adjacent poles with and without coupler is ensured. That is motion is transmitted between poles with minimal lag.

Even after providing multiple driving surfaces, the combined cross section is maintained for Male feature (5). So even if one surface comes into contact or multiple surfaces comes in contact to transmit torque for operation, entire cross section of Male feature (5) will take load of operation. So in this design strength of interlocking features have been ensured to retain basic functionality of interlocking features to drive shaft positively

ADVANTAGES OF THE INVENTION

1. Ease assembly.
2. Ease of maintenance
3. Choice to connect number of poles,
4. Isolating load from supply,
5. Making and breaking all the poles simultaneously to avoid any damage to the load
6. Reducing tooling cost.

WE CLAIM:

1. A termination pitch adjustable transmission shaft assembly for moving contact in lv switchgear products, said assembly comprising:
a cassette means;
plurality of rotor means ;
coupler means;
wherein said rotor means comprising a male feature and a female feature adapted to be operatively engaged with an identical or substantially identical female feature and male feature of another rotor means respectively so as to form transmission shaft means of a switch;
wherein said coupler means comprising a male feature and a female feature adapted to be operatively engaged with proximate pole means such that termination pitch adjustable transmission shaft being formed ensuring wide range of termination pitch.

2. Assembly as claimed in claim 1, wherein said rotor means further comprising plurality of end surfaces.

3. Assembly as claimed in claim 2, wherein said end surfaces comprising side A and side B.

4. Assembly as claimed in claims 2 and 3, wherein said side A comprising said male feature and said female feature of said rotor.

5. Assembly as claimed in claim 3, wherein side B comprising male and female feature about 180 degree opposite to said male and female feature of side A.

6. Assembly as claimed in claim any of preceding claims, wherein said male features being adapted to provide plurality of driving surfaces said side A.

7. Assembly as claimed in claim any of preceding claims, wherein said female features being adapted to provide plurality of driven surfaces of said side B.

8. Assembly as claimed in claim 1, wherein said coupler means is made up of plastic material and the like.

9. A termination pitch adjustable transmission shaft assembly for moving contact in lv switchgear products as herein substantially described and illustrated with the accompanying drawings.