Form-2
THE PATENTS ACT, 1970
COMPLETE SPECIFICATION (SECTION 10)
A POLE SHAFT SUPPORT SYSTEM FOR CIRCUIT BREAKER AND THE LIKE".
LARSEN & TOUBRO LIMITED
L&T House, Ballard Estate,
Mumbai -400 001,Mharashtra State, India
An Indian company duly registered and incorporated under
Company's Act, 1956.

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

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Field of the Invention
The present invention relates to a pole shaft support system and in particular to a pole shaft support system for circuit breakers and the like adapted to take care of problems due to jamming/sluggishness of operating shaft resulting from wide ranging manufacturing variations in shaft, shaft support and mounting or the base unit supporting a circuit breaker and favour achieving optimal performance of the circuit breaker. The support system would favour avoiding the need for complex and cost extensive high precision and control in the manufacture of shaft, shaft support and mounting or the base unit supporting a circuit breaker and yet achieve optimal performance of the circuit breaker.
Background Art
Circuit breakers are usually well known and used to open or close the operating circuitry in various electrical installations.
Usually circuit breakers are multipolar. More than one pole is adapted to open and close by driving a common shaft commonly known as a pole shaft through the circuit breaker mechanism. The pole shaft thus has to bear the reaction forces of the multiple poles in normal as well as short circuit conditions. Hence, such pole shaft in circuit breakers are required to be well supported at multiple locations to facilitate such common action in operating the multiple poles of a circuit breaker. For the purpose the support of such pole shaft is desired such that the same would be adapted for a pole shaft movement which would be free of jamming or sluggishness so as to achieve a quick motion especially in order to cater to the required short circuit ratings/conditions.
It is, however, experienced that manufacturing variations in shaft, shaft support & mounting or base points are inevitable. These variations contribute to jamming and/or sluggishness of pole shaft movement. In particular, due to manufacturing limitations occasionally there may be unevenness on the shaft, support casing for the shaft or unevenness of the base surface to which the

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circuit breaker is secured. In such situations upon installation of the circuit breaker and supporting of the operating shaft with respect to the support casing the central axis of the pole shaft does not match with the axis of support casing. Although this difference is a fraction of a millimeter, it is enough to affect the desired shaft movement leading to jamming and/or sluggishness which in turn can critically affect the performance of the circuit breaker.
To avoid such problems or to control the same to the extent possible most manufacturers therefore have to take extra precaution in manufacturing operations or secondary manufacturing methods or adjustment based design so as to achieve requisite shaft freeness. All these alternatives involve additional manufacturing constraints which lead to lower repeat accuracy and therefore lesser throughput. Moreover, the manner of achieving such high precision and control over the manufacture involve high manufacturing cost/higher rejection rates which add on to the complexities and cost factor as far as desired easy installation and optimum performance of circuit breakers are concerned.
Objects of the Invention
It is thus the basic object of the present invention to provide for a pole shaft support system for a circuit breaker and the like which would be adapted to absorb manufacturing variations in shaft, shaft support casing as well as the base unit supporting the circuit breaker and also achieve desired optimal performance of the circuit breaker.
Another object of the present invention is directed to provide for a pole shaft support system for circuit breakers and the like which would be adapted to absorb problems of misalignment of shaft with respect to its casing/support due to manufacture variations in two axes, up and down or Y axis as well as forward and backward or Z axis thereby favouring the much required simplicity and flexibility in effective installation of pole shafts in circuit breakers.

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Yet another object of the present invention is to provide for a pole shaft support system for circuit breakers and the like having means for simple .easy and cost-effective installation of the same which would facilitate convenient and smooth operation of the pole shaft to activate the multiple poles of the circuit breaker without the need for complex and cost extensive manufacturing control and precision in providing shafts, casing and the base for such circuit breakers.
Yet further object of the present invention is to provide for a support system for circuit breakers which would be simple and cost-effective to manufacture and yet would facilitate optimal and effective installation of the pole shaft to operate the multiple poles free of problems of jamming or sluggishness and also achieve the required short circuit ratings.
Yet further object of the present invention is directed to a method of simple and easy installation of pole shaft in circuit breakers free of jamming and/or sluggishness problems by simple alignment of the central axis of the shaft with respect to the axis of the support casing involving Y and Z axis adjustments to thereby absorb variations in manufacture.
Summary of the Invention
Thus according to one aspect of the present invention there is provided a pole shaft support system for circuit breakers and the like comprising: of split rings and C shape region of the support casing for Y and/or Z axis adjustments for alignment of the pole shaft with respect to said casing and/or base for free rotating motion of the pole shaft.
In accordance with one aspect the said support casing is provided with a C shaper region for holding the shaft facing said base member which is provided with atleast one ring member having a central passage through which the pole shaft traverses for support, said ring member having an inner surface and an outer surface selectively provided such that the center of the inner surface is eccentric with respect to the center of the outer surface and adapted for selective disposition in said C shaped region of said support casing to achieve

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Y and/or Z-axis adjustments for alignment of the pole shaft with respect to said casing and/or base for free rotating motion of the pole shaft
The above support system for pole shaft of circuit breakers which operates the multiple poles by way of said selective provision of means for Y and/or Z-axis adjustments is adapted to absorb manufacturing variations and problems of misalignment of the shaft with respect to the casing. Additionally, the support casing which is also adapted for Y-axis adjustability is directed to add greater flexibility to the support system for free pole shaft movement.
Importantly, the above disclosed pole shaft support system for circuit breaker of the present invention therefore on one hand provides for optimal bearing of the reaction forces of the multiple poles in the normal as well as short circuit conditions by way of effective distribution of multiple support casings as above and on the other hand does not involve the complexities and cost of high precision and control required in avoiding manufacturing variations of the shaft, its casing or the base supporting the circuit breakers.
Importantly, the Y and Z-axis adjustments possible to absorb manufacturing variations by the present support system would avoid jamming or sluggishness of pole shaft movement and provide for a simple and cost-effective alternative to tackle manufacturing variations and achieve optimal performance of circuit breakers.
In accordance with yet another preferred aspect of the present invention comprising:
- a plurality of support casings adapted to support the pole shaft of a circuit breaker with respect to a base member, each said support casing comprising a C shaped region for holding the shaft facing said base and adapted for up and down Y-axis adjustments for alignment of the pole shaft with respect to the casing and/or base ;
- said C shaped region of the support casing comprising atleast one split ring member which together define a central passage through which the pole shaft traverses for support, said split ring member defining an inner

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surface and an outer surface selectively provided such that the center of the inner surface is eccentric with respect to the center of the outer surface and adapted for slidable and selective disposition in said C shaped region of said support casing to achieve Y and/or Z-axis adjustments for alignment of the pole shaft with respect to said casing and/or base for free rotating motion of the pole shaft.
Thus in accordance with as aspect the above support system of the invention the said ring member for the Y/Z-axis adjustment means for absorption of any manufacturing variation can comprise of split rings/continuous rings which when put together form a hollow cylinder whose inner axis is selectively maintained eccentric with respect to outer center. The extent of eccentricity is based on the measure of the extent of mismatch absorption capacity of the pole shaft support in the Y-Z plane. These split rings in turn are housed in a support casing which has a Y-axis adjustability and is firmly fastened on the base.
The system which is mounted on the base, holds the pole shafts at defined locations. Due to planer irregularities, the pole shaft axis generally does not match with the axis of the support casing. However, since the split bearings have eccentric inner axis, the two splits are adapted to easily assemble such that the misaligned axis of the pole shaft exactly matches with that of the split ring combination.
In such assembling, during the Z-axis alignment in case of any unwanted Y-axis misalignment, the system additionally includes Y-axis adjustability of the support casing such that the pole shaft gets supported in the least friction condition.
In accordance with another aspect of the present invention there is provided a method of mounting the operating pole shaft of a circuit breaker free of jamming and/or sluggishness problems using the support system of the pole shaft as discussed above comprising :

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selectively adjusting the Y-Z axis alignment of the pole shaft with respect to the support casing, by selective disposition of the ring member with or without further adjustment in the Y-axis by up and down movement of the support casing.
Brief description of the drawings
The details of invention, its objects and advantages are explained hereunder in greater detail in relation to non-limiting exemplary illustrations as hereunder:
Figure 1 is an illustration showing the pole shaft supported in main
mechanism which is anchored on the base;
Figure 2 illustrates in a side and a side perspective view support casing used
in pole shaft support system of the invention ;
Figure 3a shows the support casing of pole shaft support system of the
invention; and
Figure 3b shows the ring member as a split ring adapted to be slid into the C
shaped region of the shaft support casing in the system of the invention.
Reference is first invited to accompanying Figure 1 which shows a conventional circuit breaker mechanism (1) mounted on the base (2) at locations indicted by references 3a, 3b and 3c etc. The pole shaft (4) is shown supported at multiple locations using pole shaft support casings 5a, 5b and 5c.
In order that the pole shaft (4) rotates freely it is essential that it has a minimum of friction at the various support points which requires alignment of the center of the pole shaft and the pole shaft support casing for such purpose.
Due to unevenness in anyone or more of the base surface (2), the shaft (4) surface or the supports (5a/5b/5c) from manufacturing variations, when support casing (6) of pole shaft supports at 5a, 5b, 5c are rigidly fixed on base, the central axis of the pole shaft (4) does not match with the axis of the

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support casing (6). Though the difference is a fraction of a millimeter, it is enough to make shaft rotation quite imperfect for the application and affect the circuit breaker performance.
As discussed hereinbefore, in the pole shaft support system of the invention as shown in detail in Figures 2, 3a and 3b for circuit breakers the same comprises of plurality of support casings (6) each having a C-shaped region for holding the shaft. Split rings (7) and (8) are adapted to be slid into the region C of the casing (6) such that selectively provided eccentricity between their inner and outer surface take care of the cumulative unevenness/manufacturing variations of base and shaft.
As clearly illustrated further in Figs. 2 and 3, the combination rings (7 and 8) are adapted to be slid-in together at respective location such that they completely fill and compensate the axis unevenness. The extent of eccentricity is the measure of extent of the mismatch absorption capacity of the pole shaft supports in the Y-Z plane.
Since the combination rings are essentially an eccentric circular cylinder, Z-axis (9) positioned may not always give the correspondingly desired vertical or Y-axis (10) position. This is balanced by sliding the casing vertically up and down which is also adapted for such further Y axis displacement till desired free situation is attained.
The same process is repeated at every location of pole shaft support to achieve a well supported, freely rotating pole shaft.
The split rings are locked in the final position by any of the standard mechanical means.
It is also possible that instead of the two split rings, a continuous eccentric ring slid through the shaft and supported by the casing can also serve the same purpose.

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It is thus possible by way of the present invention to provide for a pole shaft support system for circuit breakers and the like which would be adapted to absorb wide manufacturing variations and achieve optimal performance of the circuit breaker. Importantly, the system of the invention is adapted to absorb variations in two axis, up and down or Y axis or forward and backward Z axis of the circuit breaker thereby facilitating a more selective and compact disposition of the operating shaft to favour its smooth and effective operation to activate the multiple poles of a circuit breaker.
The support system for circuit breakers of the invention is thus simple and cost-effective system which would facilitate effective assembling of the pole shaft to operate the multiple poles free of problems of jamming or sluggishness and also achieve the required short circuit ratings.

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WE CLAIM :
1. A pole shaft support system for circuit breakers and the like comprising of
split or continues ring member and C shape region of the support casing for
holding the shaft facing such that the center of the inner surface is eccentric
with respect to the center of the outer surface and adapted for selective
disposition in C shape region of said support casing to achieve Y an/or Z axis
adjustments for alignment of the pole shaft with respect to said casing and/or
base for free rotating motion of the pole shaft.
2. A pole shaft support system for circuit breaker & the like as claimed in 1 wherein said ring member for the Y/Z-axis adjustment means for absorption of any manufacturing variation comprise of split rings/continuous ring portions which together define a hollow cylinder whose inner axis is selectively maintained eccentric with respect to outer centre, the extent of eccentricity being based on the measure of the extent of mismatch absorption capacity of the pole shaft support in the Y-Z plane.
3. A pole shaft support system for circuit breaker & the like as claimed 1 wherein said split rings are adapted to be slid-in together at respective location within the pole shaft support such that they completely fill and compensate the axis unevenness.
4. A pole shaft support system for circuit breaker & the like as claimed in anyone of claims 1 to 4 wherein the extent of eccentricity is selected based on the measure of extent of the mismatch absorption capacity of the pole shaft supports in the Y-Z plane.
5. A pole shaft support system for circuit breaker & the like as claimed in anyone of claims 1 to 5 comprising means to lock the split rings in the final disposition in said casing with the help of screw.

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6. A pole shaft support system for circuit breaker & the like as claimed in anyone of claims 1 to 6 wherein it is possible that instead of the two split rings, a continuous eccentric ring slid through the shaft and supported by the casing can also serve the same purpose.
7. A pole shaft support system for circuit breaker & the like substantially as herein described and illustrated with reference to the accompanying figures.
Dated this 22nd day of July, 2002

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Abstract
A pole shaft support system for circuit breaker and the like using eccentric ring design, which along with the support casing compensates for the unequal gaps between mounting surface & pole shaft in circuit breakers.
To
The Controller of Patents The Patent Office At Mumbai.