FORM 2
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
PROVISIONAL SPECIFICATION
(See section 10 and rule 13)


TITLE OF THE INVENTION
A shock absorbing means for circuit breakers
APPLICANTS
Crompton Greaves Limited, CG House, Dr Annie Besant Road, Worli, Mumbai 400 030, Maharashtra, India, an Indian Company
Inventors
Bagade Vishal Vijay and Khedkar Parag Prabhakar, both of Crompton Greaves Limited, Technology Cell (S3), A-3 MIDC, Ambad, Nasik, Maharashtra, India, both are Indian Nationals

PREAMBLE TO THE DESCRIPTION
The following specification describes the invention


This invention relates to Seismic proof Damper for Circuit Breaker.
Dampers or Shock absorbers as they are popularly known are commonly used in automobiles, railways, machine, circuit breaker etc. These means absorb the vibrating energy to provide comfort, safety etc to the vehicles, machines. There are various types of shock absorbers which uses oil, air, electromagnetic, friction etc., as the medium to absorb energy. Rubber is also one of the commonly known medium which is used for absorbing the shock, vibrations etc. The oil type and air type dampers are more costly, the construction is complicated and are prone to leakage etc. Electromagnetic and friction type have capacity limitations.
GB Patent No. 910273 discloses an invention having a spring closing mechanism for switchgear of the kind in which such mechanism and the associated linkage in contained in a fixed framework or compartment external to the main circuit-breaker compartment, shock absorbing means for absorbing the shock otherwise imparted to the framework and closing mechanism by the release of the closing spring comprises a stack of disc-like shock absorber elements housed coaxially within a movable cylindrical shock absorber casing which is connected to a member which moves the casing in one direction for charging the closing spring and is driven by the spring in the return direction when the spring is released to impart the closing effort to the mechanism. However, the independence in modification of the shape of dampers depending upon the capacity of the circuit breaker is missing in the invention disclosed herein.
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US Patent No. 4891617 discloses an invention having a molded case circuit breaker is provided with rubber stop assemblies disposed between the contact assemblies adjacent the outside poles and the cover portion of the housing. The rubber stop assemblies are disposed such that they prevent the contact assemblies from damaging the cover. The stop assemblies include a dual purpose U-shaped bracket having two parallel sets of arms. The shock absorber assembly is mounted adjacent outside poles above the contact carrier but spaced away from the inside of the cover of the circuit breaker. Thus, when the contact arm is opened, it will stop against the shock absorber and not damage the circuit breaker cover. However, the constructions features of the assembly are designed to prevent the assembly from any damage but the patent does not highlight the strength of the assembly as well the overall life of the rubber stop, which again is a crucial parameter.
Hence to overcome all the disadvantages mentioned herein a shock absorbing means for circuit breakers is disclosed herein.
An objective of the invention is to provide a shock absorbing means to protect Circuit Breaker from Seismic Vibrations.
Another objective of the invention is to provide a shock absorbing means to protect circuit breaker from operational vibrations
Another objective of the invention is to provide a shock absorbing means, which can be simple in construction and cost effective arrangement for serving above purpose without change in actual circuit breaker.
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In accordance with the invention a shock absorbing means is mounted between housing of circuit breaker or the load which it is supporting and foundation. It consists of a cylindrical damping element made of rubber type material. The damping element is mounted coaxially on shaft which is free to move vertically in support bracket. An upper support disc facilitates mounting arrangement which is used to connect damper to housing base. Similarly a lower support disc is used to connect damper with foundation. The construction of the shoe plates and support discs is such that it facilitates approximately 10 degree free tilting in all directions. It acts as self aligning bearing. Due to this arrangement the seismic vibrations in directions other than vertical will also get absorbed in damping element. This is how a single damping element can be used to absorb earth excitations in all directions.
In accordance of the invention another embodiment of this invention the above mentioned damper assembly can be used with single set of Shoe plate & Support Disc at bottom of damper and shaft top portion directly connected to housing
In accordance with the invention in yet another embodiment of the above described configuration with single set of Shoe plate & support disc can be used with self aligning bearing at support bracket & shaft connection. This facilitates additional angular degree of freedom than that provided by lower support disc & shoe plate combination.
In accordance with the invention, an embodiment can be used with multiple damping elements with stepped shaft & single set of support plate - disc combination. Use of
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multiple damping elements provides higher damping capacity. As per load requirement the number of damping elements can be increased or decreased. The pitch difference in the rubber & metal discs can be changed. Due to this variation in pitch the discs come in contact one by one hence the damping effect increases or decreases with advancement of stroke. This variable damping is also called as differential damping effect.
In accordance with the invention, the shock absorbing means works in both tension and compression and the shock absorbing material can work in compression state.
In accordance with the invention, the construction of shock absorbing means can enable both types of shocks by compression only. The life of shock absorbing material can be more in compression state than in tension state.
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In accordance with the invention the shock absorbing means can be used in both directions i.e. upwards and downwards. The construction of shock absorbing means also facilitated variable damping effect.