Claims:1. A motorized changeover switch system disconnector system (100) comprising
a first spur gear (30) fitted on a motor shaft (25) of a motor (10);
a motor support (20) providing the necessary holding arrangement to keep the motor (10) and the motor shaft (25) stable during rotation of motor (10);
a gear train including a plurality of spur gears operably coupled with the first spur gear (30);
an intermittent spur gear (60) having gear teeth on the total top half peripheral surface and intermittent gear teeth portion (65) of preset angle on the bottom half peripheral surface; the intermittent spur gear (60) coupled with the gear train including plurality of spur gears operably coupled with the first spur gear (30);
a spur gear (70) coupled with the intermittent gear teeth portion (65) of the intermittent spur gear (60); and
an output shaft (80) connecting the gear train to the changeover switch-disconnector (90); the output shaft (80) having top portion extended for manual operation of the system (100);
wherein, the engagement of the preset intermittent gear teeth portion (65) with the spur gear (70), drives the spur gear (70) and the output shaft (80), and in turn drives the changeover switch-disconnector (90); while the disengagement of the preset intermittent gear teeth portion (65) with the spur gear (70) allows to drive the changeover switch-disconnector (90) manually, independent of the gear train movable by the motor (10).
2. The motorized changeover switch disconnector system (100) as claimed in claim 1wherein the motor (10) is an electrically driven motor driving the gear train therein.
3. The motorized changeover switch disconnector system (100) as claimed in claim 1 wherein the intermittent gear teeth portion (65) is preset to the angle required to reduce the initial time lag for engagement and extent of over travel.
, Description:Field of the invention
The present invention generally relates to the gear system of motorized changeover switch disconnector, more particularly it relates to the intermittent gear arrangement in an electrically operating gear train of the changeover switch disconnector.
Background of the invention
Changeover switch disconnectors (CO-SD) are widely used to switch between the primary and backup power source, which comprises of two switch- disconnectors (SD) connected back-to-back. Changeover switch disconnectors have three stable positions such as ON-1, OFF, and ON-2 (based on the power source). Certain torque is required to drive the switch to these positions. Changeover switch-disconnector has a dead centre based mechanism. The contact system starts to move after the mechanism is operated to a particular angle to cross the dead centre. Electrically operating mechanism (EOM) is used to ease the operation by giving the required torque without manual effort. Electrically operating mechanism (EOM) is generally driven by a motor or solenoid which acts as the prime mover. In motorized changeover switch disconnector, the shaft of the CO-SD is operated through a gear arrangement coupled to a motor. Electrical supply to EOM is controlled through a control circuit which logically determines the command based on the current position of CO-SD. The gear arrangement is such that the power from the motor is effectively converted & transmitted to the driving shaft which operates the CO-SD. The Driving shaft is the connecting member between EOM and CO-SD, which transmits the torque generated by the EOM to the CO-SD. In the event of loss of control supply to operate the EOM, provision to operate the CO-SD manually by the operator is required. Such a provision should be such that the operator’s efforts are minimal.
A prior art patent EP2346055B1 discloses a switch operating device with traditional intermittent gear mechanism in which the driven gear is rotated for a particular angle and then fixed in same position till next set of teeth engage and drive it again. In this application, the driven gear is never independent of driver. The driven gear is maintained at the same position even in condition wherein it is disengaged. The input power to the intermittent gear is through the shaft and not through the gear teeth. There are cases where there is a need to isolate the driver gear from the driven gear during a particular period for reducing human effort, or for ease of operation. Motorized changeover switch disconnectors are operated by motor in electrically operated mechanism and manually through handle. During manual operation, there are chances where electrically operated mechanism (EOM) acts as an additional load i.e. the user needs to apply torque to drive the changeover switch disconnector as well as the EOM which is not needed and it becomes tougher for the user to operate. Secondly, if there is any breakage or damage of gear or jamming of gear train or motor then manual operation of CO-SD gets disabled. In high speed applications, precise control of the final output is not possible because of over travel due to system inertia. A stopper is needed to stop the gear train and final output shaft in case of over travel due to inertia. In systems where shaft is always connected to contact system through the mechanism, the force needed to drive the EOM gear train is borne by the changeover mechanism during manual operation. Also due to reduction of contact opening / contact velocity, increased wear and hence reduced performance is observed.
Thus, there exists a need for an improved system of intermittent gear arrangement inside EOM that overcomes the above mentioned drawbacks of the existing system.

Objects of the invention
The primary object of present invention is to provide an intermittent gear arrangement for manually operating the motorized changeover switch disconnector.
Another object of the present invention is to provide an intermittent gear arrangement for operating the motorized changeover switch disconnector independent of the electrically operating mechanism gear train.
Yet another object of the present invention is to provide an intermittent gear arrangement for manually operating the motorized changeover switch disconnector without any extra efforts.
Summary of the invention
The present invention, in one aspect, provides an intermittent gear mechanism for manually operating the motorized changeover switch disconnector independent of the electrically operating mechanism gear train. The gear arrangement in electrically operating mechanism is responsible for the conversion of torque delivered by the motor into the torque required by the changeover switch disconnector. Generally such gear system and changeover switch disconnector mechanism are always connected. This implies whenever the motor rotates, the changeover mechanism also rotates and the vice versa. Changeover switch disconnector is operable by electrically operating mechanism as well as manually through handle. In this approach of intermittent gear design, the electrically operating mechanism gets engaged with the changeover switch disconnector for a particular set angle sufficient to operate the switch and gets disengaged. After disengagement, changeover switch disconnector can be operated manually without extra efforts.

Brief description of the drawings
Figure 1 shows a complete construction of motorized changeover switch disconnector system with the internal construction of electrically operating mechanism, in accordance with the present invention;
Figure 2 shows the side view of gear train of the electrically operating mechanism in the changeover switch disconnector, in accordance with the present invention;
Figure 3 shows the rotating nature of the gear train of the electrically operating mechanism in the changeover switch disconnector, in accordance with the present invention;
Figure 4 shows the isomeric view of the intermittent gear in accordance with the present invention;
Figures 5, 6, 7, 8 show rotating stages of intermittent gear with its adjacent gears, 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 an intermittent gear mechanism for manually operating the motorized changeover switch disconnector system independent of the electrically operating gear train mechanism. Changeover switch disconnector system is operable by electrically operating mechanism as well as manually through handle. In an embodiment of the invention, an electrical motor acting as a prime mover drives the set of spur gears arranged to provide the torque necessary to satisfy the requirements of the equipment which the electrically operating mechanism drives. Novelty of the invention lies in that the gear train contains not only a series of standard spur gears but also an intermittent gear with a limited number of teeth. The electrical motor drives the gear train and the power is transferred continuously from one gear to another up till the intermittent gear. Power is transferred to the intermittent gear only when its gear teeth get engaged with the power transmitting spur gear in the gear train. Thus, in the approach of intermittent gear design, the electrically operating mechanism gets engaged with the changeover switch for a particular set angle sufficient to operate the switch and gets disengaged. After disengagement, the switch can be operated manually without extra efforts.
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 FIG. 1, 2 and 3, a complete construction of motorized changeover switch system disconnector (100) (hereinafter, ‘the system (100)’) with the internal construction of electrically operating mechanism, in accordance with the present invention is shown. The system (100) comprises of a motor (10) acting as a power source or prime mover; a motor support (20) providing the necessary holding arrangement to keep the motor (10) stable during rotation of motor shaft (25); a first spur gear (30) fitted on the motor shaft (25); a second spur gear (40) coupled with the first spur gear (30), a third spur gear (50) coupled with the second spur gear (40); an intermittent spur gear (60) coupled with the third spur gear (50); a fifth spur gear (70) coupled with the intermittent spur gear (60) and a output shaft (80) connecting the electrically operating mechanism to the changeover switch-disconnector (90), with the top portion of the output shaft (80) extended for manual operation of the system (100). Figure 2 shows the side view of electrically operating mechanism in the system (100), while Figure 3 shows the rotating nature of the electrically operating mechanism in the system (100) in accordance with the present invention. In one embodiment, when the motor (10) rotates anti-clockwise (as shown), the direction of rotation of respective gears is shown. The same occurs vice versa when the motor rotates in clockwise direction.
Referring to Figure 4, the isomeric view of the intermittent spur gear (60) in accordance with the present invention is shown. Top half portion of the side peripheral surface of the intermittent spur gear (60) is having gear tooth thereon, while the bottom half surface of the side peripheral surface of the intermittent spur gear (60) has intermittent gear portion (65) only for a preset angle necessary to just drive the fifth spur gear (70) to the desired angle. The extent of the angle to which the gear tooth are to be placed depends on the angle of rotation needed at the output shaft (80) and the gear ratio between the intermittent spur gear (60) and the fifth spur gear (70)’
Referring to Figures 5, 6, 7 and 8, the rotating stages of intermittent spur gear with its adjacent gears in accordance with the present invention are shown. Referring to figure 5, the intermittent spur gear (60) is engaged with the third spur gear (50), while the intermittent gear portion (65) unengaged with the fifth spur gear (70). Thus, at this stage, the intermittent spur gear (60) rotates with the third spur gear (50), but the fifth spur gear (70) remains idle.
Referring to figure 6, a condition in which the third spur gear (50) has rotated in anti-clockwise direction with respect to figure 5 is shown. The intermittent gear (60) also rotates but the fifth spur gear (70) remains idle as there is no engagement of intermittent gear portion (65) with the fifth spur gear (70).
Figure 7 shows the condition in which the intermittent gear (60) is driven by the third spur gear (50) and in turn drives the fifth spur gear (70) as at this stage, the intermittent gear portion (65) is engaged with the fifth spur gear (70). The output shaft (80) also rotates in line the fifth spur gear (70). This continues till the intermittent spur gear (60) is in contact on both sides effectively transmitting the torque.
Referring to Figure 8, the intermittent gear (60) rotates further, leaving the fifth spur gear (70) in its desired position. Further rotation of third spur gear (50) due to delayed cut off of input or inertial energy has no influence on the output shaft (80) as the intermittent spur gear (60) just rotates on its own without engagement with the output shaft (80). Figures 5, 6, 7 and 8 can be viewed in mirrored fashion for the rotation of gears in opposite direction.
In all the above referred figures, engagement portion is set at 30º providing an allowance of 330º for excess energy in the system to subside. This can be rearranged with intermittent gear sets at any required set of angles based on the need to reduce initial time lag for engagement and extent of over travel that may result in the system.
Gear arrangement in electrically operated mechanism is responsible for the conversion of the torque delivered by the motor (10) into the torque required by the changeover switch-disconnector (90). Generally, the gear system and the changeover switch disconnector (90) are always connected. This implies, whenever the motor (10) rotates, the changeover mechanism also rotates and vice versa. In the system (100), the electrically operated mechanism gets engaged with the changeover switch disconnector for a particular set angle sufficient to operate the changeover switch-disconnector (90) and gets disengaged. After disengagement, the changeover switch-disconnector (90) can be operated manually without any additional torque.
The equipment driven by the electrically operated mechanism can be a switch, switch disconnector, changeover switch disconnector or any device that requires a torque or rotational force to operate. The electrically operated mechanism that drives the changeover switch-disconnector (90)is for the purpose of illustration and it does not limit the applicability of the invention described.
Advantages of the present invention
• Manual operation of the changeover switch-disconnector (90) becomes easy to the user as it will operate the changeover switch disconnector mechanism only and not the electrically operating mechanism and its gear train or motor, due to disengagement of the intermittent spur gear (60) post completion of operation.
• Precise operation achieved at the output shaft (80) irrespective of inertial rotations of the gear train.
• Stopper to avoid over-travel of the gear Train due to its inertia is not required, which might damage the changeover switch disconnector mechanism / electrically operating mechanism components.
• Contact system operation does not get disturbed after dead centre during manual operation.
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, 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.