FORM 2
THE PATENT ACT 1970
&
The Patents Rules, 2003
COMPLETE SPECIFICATION (See section 10 and rule 13)

1. TITLE OF THE INVENTION:
"Leaf Spring Mechanism for Mounting and Un-mounting of Electrical Device"
2. APPLICANT:
(a) NAME: Larsen & Toubro Limited
(b) NATIONALITY: Indian Company registered under the
provisions of the Companies Act-1956.
(c) ADDRESS: LARSEN & TOUBRO LIMITED,
L&T House, Ballard Estate, P. O. Box: 278, Mumbai 400 001, India
3. PREAMBLE TO THE DESCRIPTION:
COMPLETE
The following specification particularly describes the invention and the manner in which it is to be performed.

Leaf Spring Mechanism for Mounting and Un-mounting of Electrical
Device
Field of the invention
The present invention relates to electrical switches and more particularly, to a leaf spring mechanism for mounting and un-mounting of an electrical device to/from a DIN-rail.
Background of the invention
An electrical device like a contactor or a miniature circuit-breaker (MCB) needs to be mounted on a DIN-rail for the purpose of an electrical installation. Thus, the electrical device needs to be locked with the DIN-rail firmly using a type of positive locking.
Generally, a DIN-clip or some kind of adaptor is used for locking and unlocking of the electrical device from the DIN-rail. In case of a single pole circuit breaker (hereinafter referred as "the breaker'), one can lock the breaker to the DIN-rail by pushing the DIN-clip towards the DIN-rail. Similarly, for unlocking the breaker from the DIN-rail one needs to pull the DIN-clip. In order to lock the breaker firmly with the DIN-rail, forceful pushing is required which is generally achieved by use of a spring in current technologies.
In other type of devices, a flexible metal wire strip or pin is used to support and engage with two sides of the DIN-clip. When the DIN-clip is pulled down by means of some tool or hand, bending of the wire strip is achieved. The metal wire strip is made up of a flexible material and works as a spring to pull down the DIN-clip. When the MCB is positioned on the DIN-rail, pressure applied on the DIN-clip by the tool or hand is released and the DIN-clip regains an original position because of the spring properties of the metal wire strip. Thus, the DIN-

clip gets locked with the DIN-rail and the MCB gets mounted on the DIN-rail. Opposite procedure is performed to unmount the MCB from the DIN-rail. However, use of tools and force many a times results in crack or breakage of external components of the electrical device.
Accordingly, there is a need for a leaf spring mechanism for mounting and unmounting of an electrical device to/from a DIN-rail.
Objects of the invention
An object of the present invention is to provide a simple mechanism for mounting and un-mounting of electrical devices.
Another object of the present invention is to avoid use of a pulling mechanism and tool like a screw driver.
Yet another object of the present invention is to save the material and tooling costs.
Summary of the invention
Accordingly, the present invention provides a leaf spring mechanism for mounting and un-mounting of an electrical device. The electrical device is mounted on a DIN-rail. The electrical device comprises a housing. The housing is configured with a protrusion on a back side thereof. The leaf spring mechanism is fitted inside the protrusion of the housing and operably engages with an upper edge of the DIN-rail. The leaf spring mechanism is capable of deforming between an expanded position and a normal position.
When the leaf spring mechanism is pressed against the upper edge of the DIN-rail by applying pressure on a surface thereof, the leaf spring mechanism acts as

a spring and gets expanded horizontally causing the protrusion of the housing to engage with the DIN-rail thereby mounting the electrical device on the DIN-rail. For un-mounting the electrical device from the DIN-rail, the leaf spring mechanism is pressed against the upper edge of the DIN-rail and the electrical device is pulled out.
Brief description of the drawings
Other features as well as the advantages of the invention will be clear from the following description.
In the appended drawings:
Figure 1 shows a front perspective view of an unlocked position of an electrical
device, in accordance with the present invention;
Figure 2 shows an exploded view of the unlocked position of the electrical device of figure 1;
Figure 3 shows a perspective view of a locked position of the electrical device mounted on a DIN-rail, in accordance with the present invention; and
Figure 4 shows a front view of a leaf spring mechanism in normal and expanded positions, in accordance with the present invention.
Detailed description of the invention
The foregoing objects of the present invention are accomplished and the problems and shortcomings associated with the prior art, techniques and approaches are overcome by the present invention as described below in the preferred embodiments.

The present invention provides a leaf spring mechanism for mounting and unmounting an electrical device from a DIM-rail. The leaf spring mechanism avoids use of a pulling mechanism and tool like a screw driver.
The present invention is illustrated with reference to the accompanying drawings, throughout which reference numbers indicate corresponding parts in the various figures. These reference numbers are shown in bracket in the following description.
Referring to figures 1-2, an electrical device (50) (hereinafter referred as "the device (50)") in an unlocked position in accordance with the present invention is shown. The device (50) comprises a housing (30). The housing (30) includes a protrusion (20) configured on a back side (not numbered) thereof. The protrusion (20) is adapted to receive a leaf spring mechanism (100) therein as shown in figure 1. In an embodiment, the shape of the protrusion (20) is designed so as to support the leaf spring mechanism (100) therein and to prevent from falling down therefrom due to gravity.
The device (50) is mounted on a DIN-rail (150). In an embodiment, the DIN-rail (150) and the leaf spring mechanism (100) are positioned offset from the device (50). In this position, the device (50) is not engaged to the DIN-rail (150) and the leaf spring mechanism (100) is in a normal position as shown in figure 4.
Referring to figure 3, a locked/mounted position of the device (50) is shown. In this position, the device (50) engages with the DIN-rail (150). An upper edge (120) of the DIN-rail (150) is pressed against the leaf spring mechanism (100) to rest thereon. Upon pressing against the edge (120) of the DIN-rail (150), the leaf spring mechanism (100) gets expanded in a transverse/horizontal direction as shown in figure 4 and provides space for the DIN-rail (150) to engage into the protrusion (20). In order to un-mount the device (50) from the DIN-rail (150), the upper edge (120) of the DIN-rail (150) is pressed against the leaf spring

mechanism (100) and the device (50) is pulled out from the DIN-rail (150). The device (50) in an unlocked position is shown in figure 2.
Again referring to figures 1-4, in an operation, when the leaf spring mechanism (100) is pressed against the upper edge (120) of the DIN-rail (150) by applying pressure on a surface (not numbered) thereof, the leaf spring mechanism (100) acts as a spring and gets expanded horizontally. The protrusion (20) of the device (50) then engages with the DIN-rail (150) thereby mounting the device (50) on the DIN-rail (150). In order to un-mount the device (50), the leaf spring mechanism (100) is pressed against the upper edge (120) of the DIN-rail (150) and the device (50) is pulled out.
Advantages of the invention
1. The leaf spring mechanism (100) provides a simple mechanism for mounting and un-mountingof the device (100).
2. The leaf spring mechanism (100) provides a grip on the DIN-rail (150) and does not require any additional clip mechanism and removing tool like a screw driver for the mounting and un-mounting operations.
3. The leaf spring mechanism (100) is easy to manufacture and saves material and tooling cost.
The foregoing descriptions of specific embodiments of the present invention have been presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the present invention to the precise forms disclosed, and obviously many modifications and variations are possible in light of the above teaching. The embodiments were chosen and described in order to best explain the principles of the present invention and its practical application, and to thereby enable others skilled in the art to best utilize the present invention

and various embodiments with various modifications as are suited to the particular use contemplated. It is understood that various omissions and substitutions of equivalents are contemplated as circumstances may suggest or render expedient, but such omissions and substitutions are intended to cover the application or implementation without departing from the spirit or scope of the claims of the present invention.

We Claim:
1. A leaf spring mechanism (100) for mounting and un-mounting of an electrical device (50), the electrical device (50) mounted on a DIN-rail (150), the electrical device (50) having a housing (30), the housing (30) being configured with a protrusion (20) on a back side thereof, characterized in that,
the leaf spring mechanism (100) being capable of fitting inside the protrusion (20) of the housing (30) and operably engaging with an upper edge (120) of the DIN-rail (150), the leaf spring mechanism (100) being capable of deforming between an expanded position and a normal position,
wherein, when the leaf spring mechanism (100) is pressed against the upper edge (120) of the DIN-rail (150) by applying pressure on a surface thereof, the leaf spring mechanism (100) acts as a spring and gets expanded horizontally causing the protrusion (20) of the housing (30) to engage with the DIN-rail (150) thereby mounting the electrical device (50) on the DIN-rail (150) and for un-mounting the electrical device (50), the leaf spring mechanism (100) is pressed against the upper edge (120) of the DIN-rail (150) and the electrical device (50) is pulled out.