FORM 2
The Patents Act 1970
(39 of 1970)
&
The Patent Rules 2003
COMPLETE SPECIFICATION
(See Section 10 and rule 13)
TITLE OF THE INVENTION:
RACK-IN SYSTEM FOR DRAW-OUT TYPE CIRCUIT BREAKERS
APPLICANT: LARSEN & TOUBRO LIMITED
L&T House, Ballard Estate, P.O. Box No. 278,
Mumbai, 400 001, Maharashtra,
INDIA.
PREAMBLE OF THE DESCRIPTION:
THE FOLLOWING SPECIFICATION PARTICULARLY DESCRIBES THE INVENTION AND THE MANNER IN WHICH IT IS TO BE PERFORMED

A) TECHNICAL FIELD
[0001] The present invention generally relates to electrical power distribution system, and particularly to circuit breakers. The present invention more particularly relates to a rack-in system for draw-out type circuit breakers.
B) BACKGROUND OF THE INVENTION
[0002] It is known that in order to cater to the requirements of distribution and protection of the end application devices, incoming power is routed through various electrical monitoring and controlling devices (hence forth called as switching devices). The use of electrical devices is well known for making, breaking and to provide safety in a typical electrical distribution system. These switching devices are mounted inside an enclosure with all electrical connections made within the enclosure for the necessary distribution and finally the required power is delivered to the end application devices.
[0003] A circuit breaker primarily consists of fix part (which is mounted on panel) and moving part (which can be inserted and can be taken out by user). Moving part consists of adapter which has to be inserted in spring loaded withdraw-able contacts of fix part. Thus there must be some mechanism which will be used to overcome this force. It should also fit within required space and should provide sufficient mechanical advantage to user. With development in technology, there are more and more compact breakers coming in market with high electric performance (which requires higher spring force thus increases force required for rack-in operation). So achieving greater mechanical advantage and occupy least space are the main challenges.

[0004] With the advancement of technology and invention of various materials, switching devices have shown a trend to become smaller for an intended power distribution and protection. Also form the point of view of usage of floor space, trend is to use minimum space required for the distribution of power with the establishments.
[0005] Thus there exists a need for an arrangement for Plug-in and Draw out of the circuit breaker modules to provide for greater mechanical advantage. There also exists a need for an arrangement to provide for compactness so that it can be fitted in a minimum available space.
[0006] The above mentioned shortcomings, disadvantages and problems are addressed herein and which will be understood by reading and studying the following specification.
C) OBJECT OF THE INVENTION
[0007] The primary object of the present invention is to develop a rack-in and draw-out arrangement for circuit breaker.
[0008] Another object of the present invention is to develop a rack-in and draw-out arrangement for molded case circuit breaker which is compact.
[0009] Yet another object of the present invention is to develop a rack-in and draw-out arrangement for circuit breaker which has greater mechanical advantage.
[0010] Yet another object of the present invention is to develop a rack-in and draw-out arrangement for circuit breaker for increasing mechanical performance.

[0011] These and other objects and advantages of the present invention
will become readily apparent from the following detailed description taken in conjunction with the accompanying drawings.
D) SUMMARY OF THE INVENTION
[0012] The above mentioned shortcomings, disadvantages and problems are addressed herein and which will be understood by reading and
studying the following specification.
[0013] The various embodiments of the present invention provide a
rack-in and draw-out arrangement for circuit breaker. The arrangement of the rack-in and draw-out type of breaker includes a fix part which is mounted on the panel and moving part which is withdraw-able for maintenance purposes. A handle is provided to facilitate rack-in and rack-out operation. The handle is engaged from front side of the moving part, and engaged with an element in the rack-in system and further rotated to carry out rack-in operation. The rotary motion is converted to translator motion of moving part by achieving high mechanical advantage. The rack-in operation is done by rotating handle, known as rack-in handle. This motion needs to be transferred to worm and worm wheel. The front portion of worm is s shaped to accommodate portion of rack-in handle. The worm is engaged with a worm wheel where the worm wheel is mounted with its vertical axis. The rotation of rack-in handle causes worm wheel to rotate providing for a high mechanical advantage.
[0014] According to an embodiment of the present invention, the worm and the worm wheel is mounted in a closed casing. The casing allows the rotation of the worm and also acts as stopper. The casing also provides

sliding guide to rack and provides a closed casing for safeguarding the worm and the worm wheel from foreign or unwanted material such as dirt.
[0015] According to one embodiment of the present invention, the
shaft lis mounted in casing which provides rotation of worm wheel. A sector of the gear called pinion 1 is mounted on same shaft to receive the same motion as that of worm wheel. The pinion 1 is in engagement with rack which slides in guide provided in casing. There is one more sector gear, pinion 2 mounted on shaft 2 supported in casing. The pinion 2 supports rack from other side and rotate with respect to the rack 9. The rack is connected to fix part shaft via link 1 and link 2. The link 2 is welded on fix part shaft. The link 1 is riveted to link at one end with a rivet 2 and to the rack at other end with a rivet 1. Thus translation motion of rack is converted into rotary motion of fix part shaft.
[0016] According to an embodiment of the present invention, two
cams are welded at the ends of fix part shaft that engages with the drop pin. The moving part is placed on a rail assembly which contains a drop plate and a drop pin mounted on it. When fix part shaft is rotated, it pushes the drop pin, the rail assembly and the moving part. A rotating of rack-in handle thereby pushes the moving part in fix part against the force of the contact spring.
E) BRIEF DESCRIPTION OF THE DRAWINGS
[0017] The other objects, features and advantages will occur to those skilled in the art from the following description of the preferred embodiment and the accompanying drawings in which:

[0018] FIG. 1 illustrates a front view of the circuit breaker showing a rack-in handle according to an embodiment of the present invention.
[0019] FIG. 2 illustrates a top view of the rack-in arrangement for circuit breaker according to an embodiment of the present invention.
[0020] FIG. 3 illustrates a perspective view of the rack-in arrangement
showing the pinion and the shaft mountings for the circuit breaker according to an embodiment of the present invention.
[0021] FIG. 4 illustrates the prospective view of the draw-out circuit breaker without the breaker assembly showing the rack-in arrangement mounted on the fixed part according to an embodiment of the present invention.
[0022] FIG. 5 illustrates the sectional view of the draw-out type circuit breaker according to an embodiment of the present invention.
[0023] Although specific features of the present invention are shown in some drawings and not in others. This is done for convenience only as each feature may be combined with any or all of the other features in accordance with the present invention.
F) DETAILED DESCRIPTION OF THE INVENTION
[0024] In the following detailed description, reference is made to the accompanying drawings that form a part hereof, and in which the specific embodiments that may be practiced is shown by way of illustration. These embodiments are described in sufficient detail to enable those skilled in the

art to practice the embodiments and it is to be understood that the logical, mechanical and other changes may be made without departing from the scope of the embodiments. The following detailed description is therefore not to be taken in a limiting sense
[0025] The various embodiments of the present invention provide a rack-in and draw-out arrangement for circuit breaker.
[0026] FIG. 1 illustrates the front view of the circuit breaker showing the rack-in handle according to an embodiment of the present invention. The arrangement of the rack-in and draw-out type of breaker includes a fix part 1 which is mounted on the panel and moving part 2 which is withdraw-able for maintenance purposes. A handle 3 is provided to facilitate rack-in and rack-out operation. The handle 3 is engaged from a front side of moving part 2, engaged with an element in the rack-in system and rotated to carry out the rack-in operation. The rotary motion is converted to translator motion of moving part 2 by achieving high mechanical advantage. The rack-in operation is performed by a rotating handle 3, known as rack-in handle.
[0027] FIG. 2 illustrates the top view of the rack-in arrangement for circuit breaker according to an embodiment of the present invention. The rack-in motion from the rotating handle 3 is transferred to a worm 4 and a worm wheel 5. The front portion of the worm 4a designed in such a way to accommodate a portion of the rack-in handle 3. The worm 4 is in engagement with the worm wheel 5. The worm wheel 5 is mounted on its vertical axis. The shaft 6 is provided for the worm wheel 5. Thus a rotation of the rack-in handle 3 causes a rotation of the worm wheel.
[0028] FIG. 3 illustrates a perspective view of the rack-in arrangement showing the pinion and the shaft mountings for the circuit breaker according

to an embodiment of the present invention. The shaft 6 is mounted in the casing 7 with along its vertical axis to provide rotation of the worm wheel 5. The sector of gear called pinion 8 is mounted on same shaft 6, thereby receiving the same motion as that of worm wheel 5. The pinion 8 is in engagement with rack 9 which slides along a guide provided in the casing 7. There is one more sector gear, pinion 10 mounted on shaft 11 supported in casing 7. The pinion 10 supports rack 9 from other side and rotate with respect to the rack 9.
[0029] FIG. 4 illustrates the prospective view of the draw-out circuit breaker (without the breaker assembly) showing the rack-in arrangement mounted on the fixed part according to one embodiment of the present invention. FIG. 5 illustrates the sectional view of the draw-out type circuit breaker according to one embodiment of the present invention. The rack 9 is connected to a fix part shaft 19 via a link 12 and a link 13. The Link 13 is welded to the fix part shaft 19. The link 12 is riveted to the link 13 at one end with rivet 15 and to the rack 9 at other end with rivet 14. Thus the translation motion of rack is converted into rotary motion of the fix part shaft 19. There are two cams 16 welded at the ends of the fix part shaft 19 that engages with the drop pin 17. The moving part 2 is placed on the rail assembly 18 which contains the drop plate with a drop pin 17 mounted on it. When fix part shaft 19 is rotated, it pushes the drop pin 17, the rail assembly 18 and thus the moving part 2. The rotation of the rack-in handle 3 thus pushes the moving part 2 in the fix part 1 against a force of the contact spring.
[0030] The arrangement uses the worm 4 and the worm wheel 5 which helps in providing a higher force reduction. The worm wheel 5 is mounted with its axis in a vertical direction to provide compactness in the arrangement. The transfer of motion from a vertical axis direction to a

horizontal axis direction (fix part shaft 19) is done with the rack 9 and the pinion 8 as well as the set of links 12 and 13.
G) ADVANTAGES OF THE INVENTION
[0031 ] The present invention is related to using worm and worm wheel arrangement in combination with rack and pinion as well as some linkages which offer greater mechanical advantage. The rack-in and draw-out arrangement of the present invention is compact enough and can be fitted into space available at the bottom of the fixed part.
[0032] The rack-in and draw-out arrangement of the present invention provides less torque experience for the user. The rack-in and draw-out arrangement of the present invention improves the scope to use higher contact spring value thus increases electrical performance of breaker.
[0033] The rack-in and draw-out arrangement of the present invention
uses worm and worm wheel which helps in providing huge force reduction. Worm wheel of the present invention is mounted with its axis in vertical direction which provides compactness in the arrangement.
[0034] Although the invention is described with various specific embodiments, it will be obvious for a person skilled in the art to practice the invention with modifications. However, all such modifications are deemed to be within the scope of the claims.
[0035] It is also to be understood that the following claims are intended to cover all of the generic and specific features of the present

invention described herein and all the statements of the scope of the invention which as a matter of language might be said to fall there between.

CLAIMS
What is claimed is:
1) A rack-in system for draw-out circuit breakers, the system comprising;
a casing;
a worm mounted in the casing;
a worm wheel engaged to the worm; and
a handle attached to the worm and the worm wheel;
a rack and pinion arrangement; and
a linkage;
Wherein the worm wheel is mounted with an axis in a vertical direction
such a rotation of the handle causes the worm wheel to rotate providing a
rack-in and rack-out operation.
2) A rack-in system according to claim 1, wherein the casing is adapted to
function as a stopper for the worm wheel.
3) A rack-in system according to claim 1, wherein the casing provides as a
sliding guide for the rack.
4) A rack-in system according to claim 1, wherein the worm is provided with
a preset profile to accommodate the handle.
5) A rack-in system according to claim 1, further comprising a shaft
mounted in the casing with its vertical axis providing rotation of the
worm wheel.
6) A rack-in system according to claim 1, wherein one pinion is mounted on
one shaft and the shaft is mounted on the other side of the casing.

7) A rack-in system according to claim 3, wherein the pinion is engaged with
the rack which slides in guide provided in the casing.
8) A rack-in system according to claim 1, wherein the rack is connected to
the shaft with at least two links.
9) A rack-in system according to claim 8, wherein a first link is welded on
the shaft and a second link is riveted to the first link at one end and to the
rack at other end.
10) A rack-in system according to claim 1, wherein linkages are adapted to convert the translation motion of the rack into rotary motion of the shaft.
11) A rack-in system according to claim 1, further comprising at least two cams are welded at end sections of the shaft that engages with drop pin.
12) A rack-in system according to claim 1, wherein a moving part is placed on a rail assembly including a drop plate with drop pin mounted on drop plate.
13) A rack-in system according to claim 1, wherein a rotation of the rack-in handle pushes the moving part in the fix part against a contact spring force.

14) A rack-in system according to claim 1, wherein the linkages and the rack and pinion arrangement provides for the transfer of motion from vertical axis direction to horizontal axis direction.