Claims:We Claim:
1. A modular padlock unit (4) for a withdrawable circuit breaker (3), the withdrawable circuit breaker (3) being capable of racking movement within a withdrawable unit (2) by rotating a racking handle (5) inserted therein for moving the withdrawable circuit breaker (3) between a connected (ON), test, disconnected (OFF) and a maintenance position with respect to switchgear, the racking handle (5) capable of being removably engaging within a hexagonal socket of a racking screw (6) disposed within the withdrawable unit (2) for facilitating racking movement of the withdrawable circuit breaker therein, the withdrawable circuit breaker (3) along with the withdrawable unit (2) enclosed within a panel board (1) having a slot configured thereon, the modular padlock unit (4) comprising of:
a lock bracket (8);
a lock plate (10) configured to engage within the lock bracket (8) using a lock plate rivet (11), the lock plate (10) having a locking surface (15) configured thereon, the lock plate (10) capable of outward pulling movement for padlocking the withdrawable circuit breaker (3);
a shutter (9) configured to engage with the lock bracket (8) and the lock plate (10) using a shutter rivet (13), the shutter (9) operably connected to the lock plate (10) to allow or restrict insertion of the racking handle (5) within the withdrawable unit (2) based on the relative position of the lock plate (10), such that the shutter (9) restricts insertion of the racking handle (5) in response to outward pulling movement of the lock plate (10) thereby padlocking the withdrawable circuit breaker (3) and restricting movement thereof, the shutter further including a shutter profile (16) for preventing padlocking following insertion of the racking handle (5) in unlocked condition;
a shutter spring (14) operably connected to the shutter (9) for providing ingress protection; and
a reset spring (12) provided for regaining initial position of the lock plate (10) in unlocked condition,
wherein in response to outward movement of the lock plate (10), the locking surface (15) blocks the shutter (9), which in turn blocks the slot configured on the panel board (1) thereby restricting insertion of the racking handle (5) within the withdrawable unit (2) for racking movement of the withdrawable circuit breaker (3) therein and safeguarding operating personnel from potential hazards, such that resetting of the lock plate (10) using the reset spring (12) releases the locked condition thereby allowing insertion of the racking handle (5) within the slot to facilitate racking movement of the withdrawable circuit breaker (3) to move between anyone of the connected (ON), test, and disconnected (OFF) position.

2. The modular padlock unit (4) as claimed in claim 1, wherein the lock plate (10) can be padlocked at any one position selected from the connected (ON), test, disconnected (OFF), and maintenance position of the withdrawable circuit breaker (3).

Dated this 29th day of March 2017

Prafulla Wange
(Agent for Applicant)
IN-PA/2058 , Description:MODULAR PADLOCK UNIT FOR WITHDRAWABLE CIRCUIT BREAKER

Field of the invention
The present invention relates to low voltage draw-out type circuit breaker and switch board modules, and more particularly provides a padlocking arrangement for draw-out type circuit breakers.
Background of the invention
Withdrawable unit (Draw-out module) is an arrangement well known in the art, which is used to connect, test, and disconnect the withdrawable circuit breaker or MCCB (Molded Case Circuit Breakers) to the main bus and removal of the circuit breaker without unbolt or disturbing the termination. The withdrawable circuit breaker has three positions- Isolated, Test and Service. Once the withdrawable circuit breaker is put into the draw-out unit that is called as isolated position, SIC will get connected at Test condition and Power contacts get connected at Service condition. In the most common type of installation, a racking handle is inserted into the draw-out unit, and is further rotated to switch the withdrawable circuit breaker between any one out of the three positions. For safety reasons only the authorized persons are allowed to operate the draw-out to take the withdrawable circuit breaker from isolated position to test and connected positions or vice versa. In order to avoid the unauthorized movement of the withdrawable circuit breaker, existing system uses a padlock unit which arrests the rotation of the racking handle in the draw-out unit for restricting unauthorized movement of the circuit breaker at ON position.

However, existing systems for padlocking face following disadvantages. In existing systems, IP shutter and Padlock mechanism are independent which leads to more components and less reliability. Further, padlocking of the draw-out circuit breaker is not possible in the panel door closed condition, in case of the withdrawable circuit breaker enclosed within panel boards. Further, position of the padlock mechanism cannot be adjusted in existing system and padlocking is possible only at test and OFF positions of the withdrawable circuit breaker. Also, the existing systems for padlocking do not provide any provision for manual resetting of the padlock.

Therefore, there exists a need to provide a padlock arrangement for padlocking the withdrawable circuit breaker at desired positions. There is a need to provide a padlock unit which overcomes the above mentioned drawbacks of the existing systems and provides safeguard to the operating personnel against potential hazards.
Objects of the invention
The primary object of present invention is to provide a modular padlock unit for padlocking the withdrawable circuit breaker at different positions.
Another object of present invention is to prevent unauthorized movement of the withdrawable circuit breaker.
Yet another object of the invention is to provide Ingress protection IP40 to the withdrawable circuit breaker.
Yet another object of present invention is to provide a quick and a reliable padlocking of the withdrawable circuit breaker for safeguarding against unauthorized movement of the withdrawable circuit breaker.
Summary of the invention
The present invention provides a modular padlock unit for a withdrawable circuit breaker. The withdrawable circuit breaker is capable of racking movement within a withdrawable unit to move between a connected (ON), test, disconnected (OFF) and a maintenance position with respect to switchgear. The withdrawable circuit breaker moves within the withdrawable unit by rotating a racking handle inserted therein.
Particularly, the racking handle engages with a hexagonal socket of a racking screw disposed within the withdrawable unit. Upon engagement of the racking handle with the racking screw, the racking handle is rotated causing movement of the withdrawable circuit breaker within the withdrawable unit for changing position thereof. The withdrawable circuit breaker along with the withdrawable unit is enclosed within a panel board having a slot configured thereon.
The modular padlock unit, configured within the panel board, comprises of a lock bracket, a lock plate, a shutter, a shutter spring, and a reset spring. The lock plate engages within the lock bracket using a lock plate rivet. The lock plate further includes a locking surface configured thereon. The lock plate is capable of outward pulling movement for padlocking the withdrawable circuit breaker at desired position.
The shutter is configured with the lock bracket having the lock plate engaged thereon, using a shutter rivet. The shutter operably connects with the lock plate and is capable of allowing or restricting insertion of the racking handle within the withdrawable unit based on relative position of the lock plate. Particularly, the shutter blocks insertion of the racking handle when the lock plate is pulled outwards, and thereby padlocks the withdrawable circuit breaker at desired position by disallowing movement thereof. The shutter further includes a shutter profile which prevents padlocking when the racking handle is inserted in unlocked condition.
The shutter spring is operably connected to the shutter and provides ingress protection even after removing the locked condition by resetting the lock plate to initial position using the reset spring. Further, in event of failure of the reset spring, the padlocked condition can be released manually by moving the lock plate inside to regain its initial position.
Padlocking of the withdrawable circuit breaker involves pulling the lock plate outwards such that the locking surface blocks the shutter. Upon outward movement of the lock plate, the shutter moves thereby blocking the slot configured on the panel board such that insertion of the racking handle through the slot is restricted by the presence of the shutter disposed therein in response to outward movement of the lock plate. Hence, the circuit breaker gets padlocked at desired position and unauthorized movement is restricted. The padlocked condition can be released by the reset spring, or manually such that the locked surface moves thereby removing the block of the shutter and allowing insertion of the racking handle within the withdrawable unit through the slot for causing racking movement of the circuit breaker.
Brief description of the drawings
Figure 1 shows a withdrawable circuit breaker mounted within panel board, in accordance with the present invention;
Figure 2 is a sectional view of figure 1 with the racking handle, in accordance with the present invention;
Figure 3 shows the withdrawable circuit breaker mounted within panel board along with the modular padlock unit, in accordance with the present invention;
Figure 4 is a sectional view of figure 3;
Figure 5 shows the modular padlock unit, in accordance with the present invention;
Figure 6 is an exploded view of figure 5;
Figure 7 shows the modular padlock unit in padlocked condition, in accordance with the present invention;
Figure 8 shows the modular padlock unit in unlocked condition, in accordance with the present invention; and
Figure 9 shows the modular padlock unit in unlocked condition with the racking handle inserted in the racking screw, in accordance with the present invention.
Detailed description of the invention
The foregoing objects of the 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 embodiment.
The present invention provides a modular padlock unit for a withdrawable circuit breaker. The modular padlock unit restricts insertion of racking handle within the withdrawable unit at desired position of the withdrawable circuit breaker thereby safeguarding the operating personnel against potential hazards.
This 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 to 9, disclosed is a modular padlock unit (4), hereinafter referred to as “the padlock unit (4)” for a withdrawable circuit breaker (3). The withdrawable circuit breaker (3) is capable of racking movement within a withdrawable unit (2) to move between a connected (ON), test, disconnected (OFF) and a maintenance position with respect to switchgear (not shown). The withdrawable circuit breaker (3) moves within the withdrawable unit (2) by rotating a racking handle (5) inserted therein. Particularly, the racking handle (5) engages with a hexagonal socket of a racking screw (6) disposed within the withdrawable unit (2). After engagement of the racking handle (5) with the hexagonal socket of the racking screw (6), the racking handle (5) is rotated by an operator thereby causing linear movement of the withdrawable circuit breaker (3) within the withdrawable unit (2) to move the withdrawable circuit breaker (3) between any of the connected (ON), test, disconnected (OFF) and the maintenance positions, as desired. The padlock unit (4) is configured with the withdrawable circuit breaker (3) and is adapted for arresting insertion of the racking handle (5) within the withdrawable unit (2) at desired position of the withdrawable circuit breaker (3) thereby locking of the withdrawable circuit breaker (3) at the desired position. In an embodiment, the withdrawable circuit breaker (3) along with the withdrawable unit (2) and the padlock unit (4) is enclosed within a panel board (1) as shown in figures 1 and 2. The panel board (1) includes a slot configured thereon.
Figures 1 and 2 shows the unlocked condition of the padlock unit (4) in which the hexagonal socket in the racking screw (6) is exposed so that the racking handle (5) can be inserted into it to perform the racking operation. Particularly, the padlock unit (4) when in unlocked condition allows the racking handle (5) to be freely inserted through the slot of the panel board (1) and engage with the hexagonal surface of the racking screw (6) for causing racking movement of the withdrawable circuit breaker (3) within the withdrawable unit (2) by rotational movement of the racking handle (5). As shown in figure 2, in unlocked condition of the padlock unit (4), the racking handle (5) is inserted through the slot into the hexagonal surface of the racking screw (6) disposed within the withdrawable unit (2), and thereinafter the racking handle (5) is rotated to move the withdrawable circuit breaker (3) to any desired position. The padlock unit (4), when in unlocked condition, allows insertion of the racking handle (5) through the slot to move the withdrawable circuit breaker (3) to any desired position thereof.
However, in locked condition of the padlock unit (4), as shown in figure 3 and figure 4, insertion of the racking handle (5) through the slot within the withdrawable unit (2) is blocked by the padlock unit (4). In an embodiment, in locked condition of the padlock unit (4), the slot of the panel board (1) is blocked by the padlock unit (4) thereby restricting entry of the racking handle (5) within the withdrawable unit (2) to perform the racking operation.
Now, referring to figures 5 and 6, in accordance with the present invention, the padlock unit (4) comprises of: of a lock bracket (8), a lock plate (10), a shutter (9), a shutter spring (14), and a reset spring (12). The lock plate (10) engages within the lock bracket (8) using a lock plate rivet (11). The lock plate (10) further includes a locking surface (15) configured thereon. The lock plate (10) is capable of outward pulling movement for padlocking the withdrawable circuit breaker (3) at any desired position thereof.
The shutter (9) is configured along with, the lock bracket (8) having the lock plate (10) engaged thereon, using a shutter rivet (13). The shutter (9) is operably connected with the lock plate (10) and allows or restricts insertion of the racking handle (5) within the withdrawable unit (2) based on relative position of the lock plate (10). In an embodiment, the shutter (9) blocks insertion of the racking handle (5) within the slot of the panel board (1) when the lock plate (10) is pulled outwards, and thus padlocks/ locks the withdrawable circuit breaker (3) at the desired position by disallowing movement thereof within the withdrawable unit (2).The shutter (9) further includes a shutter profile (16) which prevents padlocking when the racking handle (5) is inserted in unlocked condition.
The shutter spring (14) is operably connected to the shutter (9) and provides ingress protection even in unlocked condition of the padlock unit (4) even after resetting the lock plate (10) to initial position using the reset spring (12). Further, in an event of failure of the reset spring (12), the padlocked/ locked condition of the padlock unit (4) can be released manually by moving the lock plate (10) inside to regain initial position thereof.
Now, Referring to figures 7 to 9, padlocking/locking of the withdrawable circuit breaker (3) using the padlock unit (4), involves pulling the lock plate (10) outwards so that the shutter (9)blocks the slot in the panel board (1) and does not allow the racking handle (5) to insert in the withdrawable unit (2) in padlocked condition. Pulling of the lock plate (10) outwards, also results in blocking of the shutter (9) by the locking surface (15) of the lock plate (10), in padlocked condition of the padlock unit (4). More specifically, upon outward movement of the lock plate (10), the shutter (9) moves thereby blocking the slot of the panel board (1) such that insertion of the racking handle (5) through the slot is restricted by the presence of the shutter (9) disposed therein in response to outward movement of the lock plate (10). Particularly, the racking handle (5) is blocked by the shutter (9) when inserted in padlocked condition of the padlock unit (4). Since insertion of the racking handle (5) is restricted, racking operation for movement of the withdrawable circuit breaker (3) gets arrested. Hence, the withdrawable circuit breaker (3) gets locked at desired position restricting any unauthorized movement thereof.
Referring to figure 8, the padlock unit (4) can be unlocked using the reset spring (12). In an embodiment, the reset spring (12) is adapted to retain initial position of the lock plate (10) thereby releasing the locked condition of the withdrawable circuit breaker (3). In another embodiment, manual resetting can be done in event of failure or absence of the reset spring (12). Thereinafter, even after resetting the lock plate (10) and releasing the lock, the shutter (9) still provides IP40 protection by the shutter spring (14). The shutter profile (16) prevents the padlocking when the racking handle (5) is inserted. The racking handle (5) is then inserted in unlocked condition, as shown in figure 9, wherein the shutter (9) allows insertion within the slot of the panel board (1) to perform racking operation of the withdrawable circuit breaker (3) for racking movement thereof. In unlocked condition, the lock plate (10), when the racking handle (5) is in inserted condition as shown in figure 9, the lock plate (10) cannot be operated or locked which ensures the foolproof of the padlock mechanism which is achieved by the shutter profile (16).
The padlock unit (4) prevents unauthorized operation of the withdrawable circuit breaker (3) and provides adjustable padlock with IP40 for the withdrawable unit (2). The lock plate (10) can be pulled out and padlocked at any position of the withdrawable circuit breaker (3). The shutter (9) aids to attain IP40 and prevents the insertion of the racking handle (5) when the withdrawable circuit breaker (3) is padlocked. Since the IP shutter and the padlock combined in the single mechanism, it decreases the number of components and increases the reliability. The padlock unit (4) helps in locking at all positions of the withdrawable circuit breaker (3) in the withdrawable unit (2). Further, position of the padlock mechanism can be adjusted which makes it suitable for different ratings. The padlock unit (4) helps in arresting the insertion of the racking handle (5) thereby arresting the racking operation in ON condition of the withdrawable circuit breaker (3).
Advantages of the present invention
1. The padlock mechanism and Ingress protection are integrated hence the reliability has increased.
2. The padlock unit (4) is versatile, that can be adapted to different frames which reduces the cost of the product.
3. The lock plate (10) can be reset even if the reset spring (12) fails.
4. The padlock unit (4) can be operated in closed door and open door condition of the panel board (1). The withdrawable unit (2) can be locked with three padlocks in open condition as well as in panel door closed condition.
5. The padlock unit (4) is modular and can be mounted and dismounted within the withdrawable unit (2) by end user.

The foregoing objects of the invention are accomplished and the problems and shortcomings associated with prior art techniques and approaches are overcome by the present invention described in the present embodiment. Detailed descriptions of the preferred embodiment are provided herein; however, it is to be understood that the present invention may be embodied in various forms. Therefore, specific details disclosed herein are not to be interpreted as limiting, but rather as a basis for the claims and as a representative basis for teaching one skilled in the art to employ the present invention in virtually any appropriately detailed system (100), structure, or matter. The embodiments of the invention as described above and the methods disclosed herein will suggest further modification and alterations to those skilled in the art. Such further modifications and alterations may be made without departing from the spirit and scope of the invention.