FORM 2

CASE B

THE PATENTS ACT, 1970 (39 of 1970)
As amended by the Patents (Amendment) Act, 2005
&
The Patents Rules, 2003
As amended by the Patents (Amendment) Rules, 2006
COMPLETE SPECIFICATION (See section 10 and rule 13)
TITLE OF THE INVENTION
A self jigging vacuum interrupter and a method of manufacturing the same
INVENTORS
More Sachin and Kamble Deepak, both Indian nationals and both of Crompton Greaves Limited, Engineering Department, CG Global R&D Centre, Kanjur (East), Mumbai 400042, Maharashtra, India
APPLICANTS
Crompton Greaves Limited, CG House, Dr Annie Besant Road, Prabhadevi, Mumbai 400030, Maharashtra, India, an Indian Company
PREAMBLE TO THE DESCRIPTION
The following specification particularly describes the nature of this invention and the manner in which it is to be performed:

FIELD OF THE INVENTION
This invention relates to a self jigging vacuum interrupter and a method of manufacturing the same.
BACKGROUND OF THE INVENTION
A vacuum interrupter (VI) is a switching device used for interruption of fault current in power supply systems. It generally comprises a fixed side subassembly and a moving side subassembly vacuum tight brazed at the opposite ends of a ceramic bottle. The fixed side subassembly generally comprises a fixed side electrode, fixed side contact, fixed side end plate, fixed side seal cup and centre shield as discrete components. The moving side subassembly generally comprises a moving side electrode, moving side contact, moving side end plate, moving side seal cup, bellows, bellows shield, stacking ring, bush and arresting cap as discrete components. The fixed side subassembly is manufactured by introducing the fixed side electrode through the fixed side end plate and locating the fixed side end plate against a collar around the fixed side electrode followed by locating the centre shield on the fixed side endplate and around the fixed side electrode. The fixed side seal cup is located against the fixed side end plate by using a fixture. The fixed side end plate is brazed to the fixed side electrode, center shield and fixed side seal cup. The moving side subassembly is manufactured by inserting the bellows over the moving side electrode and locating one end of the bellows against a collar on the moving side electrode. Following this, the bellows shield is inserted over the bellows and its one end is located against the said one end of the bellows. The stacking ring is introduced over the moving side electrode and located against the said one end of the bellows shield and punched onto the moving side electrode. The moving side electrode is inverted and the moving side end plate is located against the other end of the bellows. The moving side seal cup is located against the moving side end plate with the help of a fixture. The said one ends of the bellows and bellows shield and the stacking ring are brazed to the moving side electrode. The other end of the bellows is brazed to the moving side endplate and the moving side seal cup is brazed to the moving


side endplate. The fixed side contact is located at the inner end of the fixed side electrode and brazed to it. Similarly the moving side contact is located at the inner end of the moving side electrode and brazed to it. The subassemblies are held at the opposite ends of a ceramic bottle with the help of fixtures and the respective seal cups are brazed to the ceramic bottle under evacuation of the ceramic bottle. The bush is inserted over the moving side electrode and the arresting cap is fitted over the bush against the moving side end plate. Manufacture of the above vacuum interrupter involves three stage brazing because of which the cycle time increases, productivity reduces and cost of manufacture increases. Manufacture is also complicated and cumbersome. As the subassemblies comprise large number of components and large number of joints, there are chances of leakage of vacuum through the joints during evacuation of the vacuum bottle. This may lead to improper evacuation of the ceramic bottle and increase the rejection rate of the vacuum interrupter and the cost of manufacture. Increased rejection rate also increases the material cost. Reliability of the vacuum interrupter is also reduced due to the large number of joints. Because of the use of the fixtures in the manufacture of the vacuum interrupter, the thermal mass increases thereby increasing the energy requirement. The three stage brazing also requires increased energy. Cost of manufacture of the vacuum interrupter also increases because of the increased energy requirement. Because of the use of the fixtures, throughput of the vacuum interrupters ie the number of vacuum interrupters that can be accommodated for brazing in a given batch reduces. As a result of this also, productivity reduces and cost of the vacuum interrupter increases. We have described in our Indian Patent Application No 1222/MUM/2006, a vacuum interrupter and a method of manufacture thereof. Such a vacuum interrupter also requires fixtures during assembly of the subassemblies and also during assembly of the subassemblies onto the ceramic bottle. Therefore, the problems associated with fixtures are encountered in such a vacuum interrupter also.
OBJECTS OF THE INVENTION
An object of the invention is to provide a self jigging vacuum interrupter which comprises reduced number of components and is economical.


Another object of the invention is to provide a self jigging vacuum interrupter which is simple in construction and easy to manufacture and is reliable.
Another object of the invention is to provide a method of manufacturing a self jigging vacuum interrupter, which method reduces cycle time of manufacture and cost of manufacture and increases productivity of the vacuum interrupter.
Another object of the invention is to provide a method of manufacturing a self jigging vacuum interrupter which method reduces the rejection rate and material cost and manufacturing cost and further increases productivity of the vacuum interrupter.
Another object of the invention is to provide a method of manufacturing a self jigging vacuum interrupter which method eliminates fixtures and increases throughput and reduces thermal mass and thermal energy requirement and cost of manufacture.
Another object of the invention is to provide a method of manufacturing a self jigging vacuum interrupter which method is simple and easy to carry out.
DETAILED DESCRIPTION OF THE INVENTION
According to the invention there is provided a self-jigging vacuum interrupter comprising a fixed side subassembly vacuum tight brazed at one end of a ceramic bottle and comprising a fixed side electrode passing through a fixed side end cup and brazed thereto, the fixed side end cup comprising locating means for locating the fixed side subassembly at the said one end of the ceramic bottle, the locating means being brazed to the said one end of the ceramic bottle and a fixed side contact brazed to the inner end of the fixed side electrode and a center shield located around the fixed side electrode and brazed to the fixed side end cup, the vacuum interrupter further comprising a moving side subassembly comprising a moving side electrode passing through a bellows with one end of the bellows located on the moving side electrode, a bellows shield disposed over the bellows with its one end located at one end of the bellows, a stacking ring


disposed over the moving side electrode and located against the said one end of the bellows shield, the said one ends of the bellows and bellows shield and the stacking ring being brazed to the moving side electrode, a moving side contact brazed to the inner end of the moving side electrode and a moving side end cup located at and brazed to the other end of the bellows and comprising a locator means for locating the moving side subassembly at the other end of the ceramic bottle, the locator means being brazed to the said other end of the ceramic bottle.
According to the invention there is also provided a method of manufacturing a self-jigging vacuum interrupter comprising :
i) assembling a fixed side subassembly by introducing a fixed side electrode through
a fixed side end cup comprising locating means and locating the fixed side end cup against a collar around the fixed side electrode, locating a fixed contact at the inner end of the fixed side electrode and locating a centre shield on the fixed side end cup around the fixed side electrode;
ii) assembling a moving side subassembly by introducing a bellows over a moving side electrode and locating one end of the bellows against a collar around the moving side electrode, locating a bellows shield over the bellows with its one end located against the said one end of the bellows, introducing a stacking ring over the moving side electrode and locating the stacking ring against the said one end of the bellows shield and punching the stacking ring onto the moving side electrode, locating a moving side contact at the inner end of the moving side electrode, inverting the moving side electrode and locating a moving side end cup comprising locator means against the other end of the bellows over the moving side electrode; and
iii) locating the fixed side subassembly and moving side subassembly at one end and the other end of a ceramic bottle with the help of the locating means and locator means respectively and brazing the fixed side end cup to the fixed side electrode, centre shield to the fixed side end cup, fixed contact to the fixed side electrode and locating means to the said one end of the ceramic body and further brazing the said one ends of the bellows and bellows shield and the stacking ring to the moving side electrode, other end of the bellows to the moving side end cup, moving side contact to the inner end of the


moving side electrode and locator means to the other end of the ceramic body under evacuation of the ceramic bottle.
The following is a detailed description of the invention with reference to the accompanying drawings, in which Figs 1 and 2 are crosssectional view and exploded view of a self-jigging vacuum interrupter according to an embodiment of the invention, respectively. The vacuum interrupter 1 as illustrated in the accompanying drawings comprises a fixed side subassembly 2 vacuum tight brazed tight brazed at one end of a ceramic bottle 3. The fixed side subassembly comprises a fixed side electrode 4 passing through a hole 5 in a fixed side end cup 6 and brazed thereto. The fixed side end cup comprises an outwardly obliquely bent L-shaped portion 7, the inner end of which is adapted to be located against the inner surface of the said one end of the ceramic bottle and the outer end of which is located at the said one end of the ceramic bottle and brazed thereto. 8 is a fixed side contact brazed to the inner end of the fixed side electrode. 9 is a centre shield located around the fixed side electrode and brazed to the fixed side end cup. 10 is a moving side subassembly comprising a moving side electrode 11 passing through a hole 12 at one end of a bellows 13 with one end of the bellows located against a collar 14 on the moving side electrode. 15 is a bellows shield disposed over the moving side electrode through a hole 16 at one end of the bellows shield and located over the bellows with said one end of the bellows shield located against said one end of the bellows. 17 is a stacking ring disposed over the moving side electrode and located against the said one end of the bellows shield. The said one ends of the bellows and bellows shield and the stacking ring are brazed to the moving side electrode. 18 is a moving side contact brazed to the inner end of the moving side electrode. 19 is a moving side end cup comprising an outwardly obliquely bent L-shaped section 20, the inner end of which is adapted to be located against the inner surface of the said other end of the ceramic bottle and the outer end of which is located at the said other end of the ceramic bottle and brazed thereto. The fixed side subassembly is assembled by introducing the fixed side electrode through the hole 5 in the fixed side end cup and locating the fixed side end cup against a collar 21 around the


fixed side electrode. The fixed contact 8 formed with a recess (not shown but can be seen in Fig 1) corresponding to the inner end of the fixed side electrode is located at the inner end of the fixed side electrode by engaging the inner end of the fixed side electrode in the recess in the fixed contact. The centre shield is located on the fixed side end cup around the fixed side electrode. The moving side subassembly is assembled by introducing the bellows over the moving side electrode through hole 12 at one end of the bellows and locating the said one end of the bellows against the collar 14 around the moving side electrode. The bellow shield is introduced over the moving side electrode through the hole 16 at one end thereof and located over the bellows with its one end located against the said one end of the bellows. The stacking ring 17 is introduced over the moving side electrode and located against the said one end of the bellows shield. The stacking ring is punched onto the moving side electrode. The moving side contact formed with a notch (not shown but can be seen in Fig 1) corresponding to the inner end of the moving side electrode is located at the inner end of the moving side electrode by engaging the inner end of the moving side electrode in the notch in the moving side contact. The moving side electrode is inverted and the moving side end cup is located against the other end of the bellows over the moving side electrode through a hole 22 in the moving side end cup. The fixed side subassembly and moving side subassembly are located at said one end and said other end of the ceramic bottle respectively with the help of the obliquely bent L-shaped portion and obliquely bent L-shaped section respectively. Under evacuation the fixed side end cup is brazed to the fixed side electrode and centre shield. The fixed contact is brazed to the fixed side electrode and the L-shaped bent portion is brazed to said one end of the ceramic body. The said one ends of the bellows and bellow shield and the stacking ring are brazed to the moving side electrode. The other end of the bellows is brazed to the moving side end cup. The moving side contact is brazed to the inner end of the moving side electrode. The L-shaped section is brazed to the other end of the ceramic body. The tapped holes 23 and 24, respectively at the outer ends of the fixed side electrode and moving side electrode are for connecting the fixed side electrode and moving side electrode to switching devices like vacuum switches.


The self jigging or self locating vacuum interrupter of the invention do not require the fixtures normally associated with manufacture of vacuum interrupters. It also reduces the number of joints and the number of components. Brazing is carried out only at the final stage of manufacture, namely at the time of brazing the subassemblies onto the ceramic bottle. Because of the single shot brazing, cycle time of manufacture and cost of manufacture are reduced and productivity is increased. As the number of joints have been reduced, rejection due to vacuum leakage is reduced and reliability of the vacuum interrupter is increased. Due to elimination of the fixtures, throughput ie number of vacuum interrupters that can be accommodated in a given batch of vacuum interrupters is increased and thermal mass and thermal energy requirement and cost of manufacture are reduced. The method of the invention is simple and easy to carry out. The construction of the vacuum interrupter is also made rendered simple and easy. The vacuum interrupter of the invention is also economical for the above reasons.
The locating means comprising the outwardly obliquely bent L-shaped portion and the locator means comprising the outwardly obliquely bent L-shaped section can be of different geometry / configuration integrated with the end cups. Such variations of the invention are obvious to those skilled in the art and the scope of the invention should be construed and understood accordingly.


We claim :
1. A self-jigging vacuum interrupter comprising a fixed side subassembly vacuum tight brazed at one end of a ceramic bottle and comprising a fixed side electrode passing through a fixed side end cup and brazed thereto, the fixed side end cup comprising locating means for locating the fixed side subassembly at the said one end of the ceramic bottle, the locating means being brazed to the said one end of the ceramic bottle and a fixed side contact brazed to the inner end of the fixed side electrode and a center shield located around the fixed side electrode and brazed to the fixed side end cup, the vacuum interrupter further comprising a moving side subassembly comprising a moving side electrode passing through a bellows with one end of the bellows located on the moving side electrode, a bellows shield disposed over the bellows with its one end located at one end of the bellows, a stacking ring disposed over the moving side electrode and located against the said one end of the bellows shield, the said one ends of the bellows and bellows shield and the stacking ring being brazed to the moving side electrode, a moving side contact brazed to the inner end of the moving side electrode and a moving side end cup located at and brazed to the other end of the bellows and comprising a locator means for locating the moving side subassembly at the other end of the ceramic bottle, the locator means being brazed to the said other end of the ceramic bottle.
2) The self jigging vacuum interrupter as claimed in claim 1, wherein the locating means comprises an outwardly obliquely bent L-shaped portion, the inner end of which is adapted to be located against the inner surface of the said one end of the ceramic bottle and the outer end of which is adapted to be located at the said one end of the ceramic bottle and brazed thereto and the locator means comprises an outwardly obliquely bent L-shaped section, the inner end of which is adapted to be located against the inner surface of the said other end of the ceramic bottle and the outer end of which is adapted to be located at the said other end of the ceramic bottle and brazed thereto.


3) A method of manufacturing a self-jigging vacuum interrupter comprising :
i) assembling a fixed side subassembly by introducing a fixed side electrode through
a fixed side end cup comprising locating means and locating the fixed side end cup against a collar around the fixed side electrode, locating a fixed contact at the inner end of the fixed side electrode and locating a centre shield on the fixed side end cup around the fixed side electrode;
ii) assembling a moving side subassembly by introducing a bellows over a moving side electrode and locating one end of the bellows against a collar around the moving side electrode, locating a bellows shield over the bellows with its one end located against the said one end of the bellows, introducing a stacking ring over the moving side electrode and locating the stacking ring against the said one end of the bellows shield and punching the stacking ring onto the moving side electrode, locating a moving side contact at the inner end of the moving side electrode, inverting the moving side electrode and locating a moving side end cup comprising locator means against the other end of the bellows over the moving side electrode; and
iii) locating the fixed side subassembly and moving side subassembly at one end and the other end of a ceramic bottle with the help of the locating means and locator means respectively and brazing the fixed side end cup to the fixed side electrode, centre shield to the fixed side end cup, fixed contact to the fixed side electrode and locating means to the said one end of the ceramic body and further brazing the said one ends of the bellows and bellows shield and the stacking ring to the moving side electrode, other end of the bellows to the moving side end cup, moving side contact to the inner end of the moving side electrode and locator means to the other end of the ceramic body under evacuation of the ceramic bottle.
4) The method as claimed in claim 3, which is carried out with a fixed side end cup
having locating means comprising an outwardly obliquely bent L-shaped portion, the
inner end of which is adapted to be located against the inner surface of the said one end


of the ceramic bottle and the outer end of which is adapted to be located at the said one end of the ceramic bottle and brazed thereto and with a moving side end cup having locator means comprising an outwardly obliquely bent L-shaped section, the inner end of which is adapted to be located against the inner surface of the said other end of the ceramic bottle and the outer end of which is adapted to be located at the said other end of the ceramic bottle and brazed thereto.

Abstract
A self-jigging vacuum interrupter (1) comprising a fixed side subassembly (2) vacuum tight brazed at one end of a ceramic bottle (3). The fixed side subassembly comprises a fixed side electrode (4) passing through a fixed side end cup (6) and brazed thereto. The fixed side end cup comprises locating means (7) for locating the fixed side subassembly at the said one end of the ceramic bottle. The locating means is brazed to the said one end of the ceramic bottle. A fixed side contact (8) is brazed to the inner end of the fixed side electrode and a center shield (9) is located around the fixed side electrode and brazed to the fixed side end cup. The vacuum interrupter further comprises a moving side subassembly (10) comprising a moving side electrode (11) passing through a bellows (13) with one end of the bellows located on the moving side electrode. A bellows shield (15) disposed over the bellows with its one end located at one end of the bellows. A stacking ring (17) is disposed over the moving side electrode and located against the said one end of the bellows shield. The said one ends of the bellows and bellows shield and the stacking ring are brazed to the moving side electrode. A moving side contact (18) is brazed to the inner end of the moving side electrode and a moving side end cup (19) is located at and brazed to the other end of the bellows. The moving side end cup comprises a locator means (20) for locating the moving side subassembly at the other end of the ceramic bottle. The locator means is brazed to the said other end of the ceramic bottle. Also a method of manufacturing the self-jigging vacuum interrupter (Fig 1).