F O R M 2
THE PATENTS ACT, 1970
(39 of 1970)
&
The Patents Rules, 2003
PROVISIONAL SPECIFICATION
(See section 10; rule 13)
1. Title of the invention. – “LOCKING ARRANGEMENT FOR MOUNTING / UNMOUNTING CIRCUIT BREAKER ON / FROM DIN RAIL”
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 describes the invention

FIELD OF INVENTION
The present invention relates to a locking / unlocking arrangement in DIN clip for mounting / unmounting circuit breakers on / from DIN rail. The invention, particularly, relates to a locking / unlocking arrangement in DIN clip adapted to mount or unmount low voltage circuit breakers, electrical or- electronic devices such as miniature circuit breaker (MCB), moulded case circuit breaker (MCCB) or any other modular devices and the like on or from the DIN rail. This ensures safe, hassle-free mounting and unmounting of the devices from the DIN rail, without causing any damage to it.
BACKGROUND AND PRIOR ART
Circuit Breaker needs to be mounted on Din Rail for the purpose of any electrical installation and for this device needs to be locked with the rail firmly. To achieve this some kind of positive locking is required.
Generally Din Clip or some kind of adaptor is used for locking and unlocking of device from Din Rail. If it is a single pole breaker one can lock the breaker to the rail by pushing the clip towards rail, same way for unlocking the device from the rail one need to pull the clip. Same procedure is being followed for multipole breaker which is time consuming and causes damages to the product too while locking/unlocking with the rail and it becomes extremely difficult for a individual to lock / unlock multipole device at a time.
US4900275 deals with the means to mount a split-case circuit breaker in closely spaced relationship to an elongated channel shaped rail having laterally spaced oppositely projecting
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abutment flanges. The circuit breaker shell defines a guide-way for receiving a resilient one-piece plastic latch-member having a T-shape. The base of the T has one end for engaging the end of the abutment flanges which is not engaged by the circuit-breaker shell and the other end of the T defines a slot for receiving a tool such as a screwdriver to facilitate the movement of the member. The resiliency of the plastic tends to return the latch towards its normal or latch position and is only overcome by the force exerted by the tool to move the latch to its released position in order to permit the breaker to be assembled with the rail or removed from the rail. Thus this invention only talks about one permanent position of the latch member, which is locked on to the rail, and one temporary position, achieved by putting a screwdriver, for unlocking the' breaker. The stay-put feature is not achieved.
US Patent Application No. 20050175402 describes an apparatus for detachably mounting a device to a rail. The rail has generally oppositely facing first and second edges, each having adjacent front and back faces. The apparatus includes a bracket on the device. The bracket has a recess for receiving the first edge of the rail. The recess includes a lip for engaging the back face of the rail adjacent the first edge. The apparatus also includes a clamp on the device. The clamp has a resilient wing for resiliently engaging the front face of the rail, proximal to the engagement between the rail and the lip. The apparatus further includes a latch for engaging the back face of the rail adjacent the second edge against the bias of the clamp. The stay-put feature is not achieved here as well as the life of this will be less compared to our invention which might render the breaker useless even before its electrical life finishes.
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Thus there is a need to provide for a locking arrangement in DIN clip for mounting / unmounting circuit breakers on / from DIN rail such that a number of-single pole breaker as well as multi-pole breakers can be locked / unlocked with the DIN rail easily by an individual without causing any damage to the device that too in less time and with a single screw driver.
The present inventors have found that a locking / unlocking arrangement comprising several components in operative integration with each other in a manner that hold of the DIN clip in a predetermined intermediate position is achieved such that DIN clip is in a meta-stable condition where a little push or pull is required to mount or unmount single pole or multi-pole device on or from the rail. The problems with the prior art and existing DIN clip or some kind of adaptor used for locking and unlocking of the device from the DIN rail can be overcome adopting the locking arrangement of the present invention.
OBJECTS OF INVENTION
Thus the one of the objects of the present invention is to provide a locking / unlocking arrangement on DIN clip for mounting or unmounting of low voltage circuit breakers, other switching devices and the like on or from the DIN rail.
Another object of the present invention is to provide a locking / unlocking arrangement which can hold the DIN clip in an intermediate position.
Yet another object of the present invention is to provide locking / unlocking of single pole breakers as well as multi-pole breakers in a less time.
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Further object of the present invention to provide a locking / unlocking arrangement wherein a single screw driver can be used to lock or unlock the device.
SUMMARY OF INVENTION
Thus according to one aspect of the present invention there is provided an arrangement for mounting and or unmounting circuit breakers, said arrangement comprising :
housing;
clip means encapsulated in said housing, said clip means being profiled having predetermined curvature and comprises plurality of slot means so as to arrest the circuit breaker with mounting channel means on the circuit breaker is mounted;
guide means operatively provided in the housing so as to restrain the clip means from over travel; and
spring means being provided in the slot means such that the clip means can be held in a predetermined metastable position.
DETAILED DESCRIPTION OF INVENTION
The arrangement of the present invention comprises a housing having a pair of walls extending from rear bottom side of the housing. The housing, and more particularly, the walls encapsulates a rectangular clip means which arrests the low voltage circuit breakers, electrical or electronic devices such as miniature circuit breaker " (MCB), moulded case circuit
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breaker (MCCB) or any other modular devices and the like with mounting channel / DIN rail. The walls are rectangular "C" shaped placed parallely to each other with angular chamfering done on extreme right hand corner in a manner that it is parallel to locking edge means of the said clip means.
In another embodiment of the present invention the rear bottom end of the housing comprises of extended projection means {herein described as "stopper") such that it guides the horizontal movement of the clip means and also acts as a stopper for the 'clip means so as to restrain the clip means from over travel.
In another embodiment of the present invention the rectangular clip means comprises a DIN clip having rectangular profile on front and predetermined angular curvature at its both ends. The said curvature possesses an inverse obtuse angle of approximately 120 degrees. The DIN clip comprises plurality of slot means comprising of tool slots and spring slot. The tool slot is oval-shaped so as to accommodate a tool (herein it is screw driver) to pull the clip down in mounted condition for unlocking the device from the mounting channel / DIN rail. The spring slot comprises predetermined rectangular opening / aperture in the clip at the front end of the clip so that it is able to accommodate spring means in vertical position. The spring means comprises compression spring .disposed vertically in between the din clip where one end of the spring is mounted on the stopper provided in the housing and the other side resting on the interior part of the spring slot (herein described as "spring resting wall") which is rectangular in shape having a protrusion which acts as a guiding surface for the compression spring on the rear front housing.
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Yet in another embodiment of the present invention the Din clip is chamfered in a angular manner (herein referred to as "locking edge") to arrest the mounting channel / DIN rail.
In another embodiment the arrangement of the present invention comprises plurality of singular projections (herein referred to as "chamfer for stay put") provided on either side of the clip. There are four chamfers two on each side of the clip i.e. two on front end of the clip and two on the rear end of the clip. The chamfers for stay put located on the front end are flat shaped projections while the chamfers at the rear end of the clip are angular projections, profiled angularly in a unique manner so as to provide, sliding motion of the chamfers into the DIN clip resting walls is possible. The angular profile in the DIN clip allows the DIN clip for rotation and the flat chamfer allows the clip to stay in the extended state.
BRIEF DESCRIPTION OF ACCOMPANYING FIGURES
Figure 1 illustrates an outline sketch showing the unlocked condition of the DIN clip in the present invention when the spring is compressed.
Figure 2 illustrates an outline sketch showing the locked condition of the DIN clip in the present invention when the spring is released.
Figure 3 illustrates an outline drawing showing the stay-put condition when the spring is charged and the clip is held in position by a chamfer in the present invention.
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Figure 4 illustrates the stay-put condition detailing the chamfer position, the tool slot and the spring slot in the DIN clip in the present invention.
Figure 5 illustrates an isometric view of spring and the interlocking arrangement of spring with the said clip in the present invention.
Figure 6 shows the isometric view of the used Compression Spring of the present invention.
DETAIL DESCRIPTION OF ACCOMPANYING FIGURES
Figure 1 is an outline drawing showing the unlocked condition of the DIN clip when the spring (as shown in Figure 5) is compressed. The MCB (or any other modular device) is not held on to the DIN rail (2) at this condition, since the locking edge (3) (indicated in figure 2) of the clip (1) stays back and the spring (4) (as shown in Figures 5 & 6} in the clip (1) is compressed.
Figure 2 illustrates the locked condition of the DIN clip (1), when the spring (4) is released. The MCB (or any other modular device) is held on to the DIN rail (2) firmly at this condition, since the locking edge (3) of the clip (1) locks the device housing (5) to the DIN rail (2) and the spring (4) (shown in figures 5 & 6) in the DIN clip (1) is released. This is a stable position of the DIN Clip assembly.
Figure 3 is an outline drawing showing the stay-put condition when the spring (4) is charged and the clip (1) is held in position by chamfer (6) because of its angular shape, which becomes parallel to the stoppers (not shown here) when tilted, thereby holding the clip in stay-put condition. The MCB (or any other modular device) is not held on to the DIN rail (2)
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firmly at this condition/ since the locking edge (3) of the DIN clip (1) is away from the rail (2), the clip (1) is tilted backward a little and the spring (4) in the clip (1) is charged. This is a metastable condition of the DIN Clip (1) and a little push forward ensures that the clip (1) no longer rests on the chamfer (6) and the clip (1) goes to locked condition.
Figure 4 shows the stay-put condition detailing the chamfer (6), the tool slot (7) and the spring slot (8) in the DIN clip (1) . Any tool (herein it is screw driver not shown in the figures) is inserted into tool slot (7) and the clip (1) is pulled up and pushed back where it rests against the chamfer (6), which restricts the DIN clip (1) to move back to locked condition, thereby making it remain metastable.
In figure 5 isometric view of the spring and the interlocking arrangement of spring with the said clip has been illustrated. Spring (4) {also shown in figure 6) is accommodated in the spring slot (8). On the spring resting walls (9) one side of spring (4) is mounted and the. other side is mounted on the stopper (not shown in the figures) provided in the housing (5).
Dated this 25th day of March, 2006.

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