Worm And Worm Wheel Drive For Energy Storing Device.


Updated about 2 years ago

Abstract

A worm and worm wheel drive for energy storing device, said device comprising: a worm gear adapted to be angularly displaced about its central axis, resulting in its rotation; a worm element adapted to be driven by a motor for its angular displacement along its angular displacement axis; a spring wheel adapted to be co-axially disposed on said worm gear, said spring wheel having a first diameter which is relatively lesser in diameter than said worm gear, said spring wheel further comprising an extended segment such that a second diameter (taken from the circumference of said extended segment to the non-extended circumference of said spring wheel) is greater than said first diameter of said spring wheel but lesser than the diameter of said worm gear; a latch adapted to engage with roller(s) at the circumference of said spring wheel in order to lock its position, said engagement depending upon pre-defined engagement parameters in relation to charging position; a spring adapted to be placed operatively below said worm gear; an end plate adapted to be located operatively beneath said spring, said spring extending operatively downwards to culminate into said end plate; a shaft / spring rod with a first end adapted to be coupled, indirectly, to said worm gear and a second end adapted to be connected to said end plate; and an eccentric element on said worm gear such that it can come into contact with an edge of said extended segment of said spring wheel.

Information

Application ID 2858/MUM/2012
Invention Field MECHANICAL ENGINEERING
Date of Application 2012-09-28
Publication Number 23/2014

Applicants

Name Address Country Nationality
CROMPTON GREAVES LIMITED CG HOUSE, 6TH FLOOR, DR. ANNIE BESANT ROAD, WORLI, MUMBAI - 400 030, MAHARASHTRA, INDIA. India India

Inventors

Name Address Country Nationality
TELI KUNAL CROMPTON GREAVES LTD, ANALYTICS CENTRE, GLOBAL R&D CENTRE, KANJURMARG (E), MUMBAI-400042, MAHARASHTRA, INDIA India India
ROY DEOSHARAN CROMPTON GREAVES LTD, ANALYTICS CENTRE, GLOBAL R&D CENTRE, KANJURMARG (E), MUMBAI-400042, MAHARASHTRA, INDIA India India
CHAVAN KETAN CROMPTON GREAVES LTD, ANALYTICS CENTRE, GLOBAL R&D CENTRE, KANJURMARG (E), MUMBAI-400042, MAHARASHTRA, INDIA India India
GUPTA VIJENDRA CROMPTON GREAVES LTD, ANALYTICS CENTRE, GLOBAL R&D CENTRE, KANJURMARG (E), MUMBAI-400042, MAHARASHTRA, INDIA India India
SHIVAKUMAR MEGHAVATH CROMPTON GREAVES LTD, ANALYTICS CENTRE, GLOBAL R&D CENTRE, KANJURMARG (E), MUMBAI-400042, MAHARASHTRA, INDIA India India

Specification

FORM 2
THE PATENTS ACT, 1970
(39 of 1970)
As amended by the Patents (Amendment) Act, 2005
AND
The Patents Rules, 2003
As amended by the Patents (Amendment) Rules, 2006
COMPLETE SPECIFICATION
(See section 10 and rule 13)
TITLE OF THE INVENTION
Worm and worm wheel drive for energy storing device.
APPLICANT(S):
Crompton Greaves Limited, CG House, Dr Annie Besant Road, Worli, Mumbai 400 030, Maharashtra, India, an Indian Company
INVENTOR(S):
Teli Kunal, Roy Deosharan, Chavan Ketan, Gupta Vijendra, Shivakumar Meghavath; all of Crompton Greaves Ltd, Analytics Centre, Global R&D Centre, Kanjurmarg (E), Mumbai-400042, Maharashtra, India, all Indian Nationals; all Indian Nationals.
PREAMBLE TO THE DESCRIPTION
The following specification particularly describes the nature of this invention and the manner in which it is to be performed:

FIELD OF THE INVENTION
This invention relates to the field of mechanical engineering.
Particularly, this invention relates to mechanical assemblies and mechanical engineering with respect to switchgear equipment.
Specifically, this invention relates to a worm and worm wheel drive for energy storing device.
BACKGROUND OF THE INVENTION
Switchgear equipment comprise circuit breaker mechanisms. Circuit Breaker mechanisms are used in electrical equipment, as an adjunct mechanism, for preventing said electrical equipment from current / voltage aberrations such as overload, short circuit, or the like. Basically, it is designed to detect a fault condition, and operates to interrupt the working of the associated electrical equipment upon detection, thereby saving its health.
Once a fault is detected, contacts within the circuit breaker must open to interrupt the circuit; some mechanically-stored energy (using something such as springs or compressed air) contained within the breaker is used to separate the contacts. Larger units have coils to trip the mechanism, and electric motors to restore energy to the springs.
A trip coil is a type of solenoid in which the moving armature opens a circuit

breaker or other protective device when the coil current exceeds a predetermined value. A closing coil is adapted to shut the circuit breaker completely.
In its working mode, if a power surge occurs in the electrical system, the breaker will trip. This means that a breaker that was in the "on" position will flip to the "off position and shut down the electrical power leading from that breaker. Essentially, a circuit breaker is a safety device. When a circuit breaker is tripped, it may prevent a fire from starting on an overloaded circuit; it can also prevent the destruction of the device that is drawing the electricity.
Figure 1 illustrates a schematic of the closing spring and its associated mechanism for charging, in a circuit breaker mechanism of the prior art.
In existing circuit breaker mechanisms, a Ratchet-pawl mechanism with motor is used to charge a closing spring. Charging time of the closing spring is a critical factor. It depends on torque required to charge the spring. Closing spring is guided in a metallic drum which is fixed to mechanism frame. Motor is used to charge the closing spring via the ratchet-pawl mechanism. It includes a ratchet wheel (12) adapted to be angularly displaced through its 360 degree rotation cycle. It further includes a co-axially (17) fitted drum (13), attached to it at its base. A shaft (14) is connected to the ratchet wheel, spaced-apart from the centre of the ratchet wheel, and hangs down into said drum. The drum, includes a co-axially fitted closing spring, which is compressed in its charged-up configuration. There is provided an end plate (15), at the operative bottom of the drum and spring, connected to the operative bottom end of the shaft.
This mechanism works as a slider crank mechanism. As the ratchet wheel angularly displaces, the connected shaft moves up and down (16). This connecting

shaft is used to transfer the forces from ratchet wheel to bottom of closing spring i.e. at the end plate. During the rotation of wheel, there is change in angle of connecting rod. This motion, brings the end plate operatively upwards, and this force results in the compression of the closing spring, thus charging it to be used, upon detection fault.
It has been observed that the goodness of a circuit breaker is a function of its charging time, the amount of torque / energy spent on charging, and the ease of charging. Also, in the above mechanism, that the shaft is tilted (not always coaxial) due to its connecting arrangement and the drum remains fixed, co-axially, which results in exulting lateral pressure on the inner waJJs of the drum, and causing friction, thereby requiring more energy to be spent on charging / compressing said spring.
The ratchet wheel, therefore, imparts potential energy to closing spring. Typically, the rod is adapted to be linearly displaced which is achieved by half rotation of the ratchet wheel. The ratchet wheel rotates incrementally by virtue of a teethed rim. Generally, it requires 15 seconds to complete the half rotation. Sometimes, there may be failures due to breakage of teeth due to relatively high stresses involved.
There is a need to obviate the concerns of the prior art.
US5280258A discloses a circuit breaker charging mechanism and its components
where in the rod is affixed at its bottom end to a pin to support spring and the
document.
US7696447 discloses a mounting assembly that includes connectors extending outwardly to mount the spring energy assembly.

Further, in prior art mechanisms, rachet-pawl mechanism, chain drive and cam-roller were used to charge the spring.
Due to the prior art arrangement, the following disadvantages of the existing practices were observed:
1. Energy storage per unit volume was less; so, more space was required for the mechanism;
2. Manufacturing of ratchet wheel was costly;
3. Failure of ratchet wheel (due to the single line contact between ratchet and pawl);
4. Eccentric cam shaft was required for ratchet pawl arrangement;
5. Special crank arrangement was required to avoid the bending of ratchet wheel;
6. Due to the slippage of pawl, reverse rotation of ratchet wheel was possible (result in failure of system).
OBJECTS OF THE INVENTION
An object of the invention is to provide a mechanism which increases energy storage per unit volume.
Yet another object of the invention is to reduce cost of manufacturing of ratchet wheel.
Still another object of the invention is to avoid failure of ratchet wheel (due to the single line contact between ratchet and pawl) in an energy storage mechanism.

An additional object of the invention is to eliminate the use of an eccentric cam shaft for ratchet pawl arrangement in an energy storage mechanism.
Still an additional object of the invention is to eliminate failure related to slippage of pawl in an energy storage mechanism.
Another additional object of the invention is to eliminate reverse rotation of ratchet wheel in an energy storage mechanism.
Yet another additional object of the invention is to provide an energy storage mechanism with reduction in linkages.
SUMMARY OF THE INVENTION
According to this invention, there is provided a worm and worm wheel drive for energy storing device, said device comprises:
a) a worm gear adapted to be angularly displaced about its central axis, resulting in its rotation;
b) a worm element adapted to be driven by a motor for its angular displacement along its angular displacement axis;
c) a spring wheel adapted to be co-axially disposed on said worm gear, said spring wheel having a first diameter which is relatively lesser in diameter than said worm gear, said spring wheel further comprising an extended segment such that a second diameter (taken from the circumference of said extended segment to the non-extended circumference of said spring wheel) is greater than said first diameter of said spring wheel but lesser than the diameter of said worm gear;

d) a latch adapted to engage with roller(s) at the circumference of said spring wheel in order to lock its position, said engagement depending upon predefined engagement parameters in relation to charging position;
e) a spring adapted to be placed operatively below said worm gear;
f) an end plate adapted to be located operatively beneath said spring, said spring extending operatively downwards to culminate into said end plate;
g) a shaft / spring rod with a first end adapted to be coupled, indirectly, to said worm gear and a second end adapted to be connected to said end plate; and
h) an eccentric element on said worm gear such that it can come into contact with an edge of said extended segment of said spring wheel.
Typically, said worm gear has a defined axis of installation with respect to said device.
Typically, said spring is an operative vertical closing spring, adapted to be compressed in order for storage of energy.
Typically, said device comprises a drum guide, spaced apart from said worm gear, adapted to house said spring.
Typically, said device comprises a drum guide adapted to envelope said spring with both spring and drum guide having a common axis.
Typically, said worm element engages with said worm gear to form a worm and worm wheel drive element.
Typically, said motor is connected to said worm element through bevel gears.

Typically, said spring wheel is superimposed on to said worm gear.
Typically, an operative upper end of said spring rod is attached to said spring wheel such that the point of attachment is offset from the centre of said spring wheel.
Typically, said spring wheel is adapted to independently rotate inside said worm gear.
Typically, said eccentric element is located at the edge of said worm gear. According to this invention, there is provided a method for energy storage using worm and worm wheel drive in an energy storing device, said method comprises the steps of: i. angularly displacing said worm element, in a first direction, by said motor; ii. angularly displacing said worm gear, in said first direction, by said worm
element; iii. engaging said eccentric element, on said worm gear, with said extended
segment of said spring wheel in order to simultaneously drive said worm
gear and said spring wheel from an operative bottom position to an operative
top position, thereby completing a first 180 degree angular displacement iv. linearly displacing said shaft / spring rod in an operative vertical linearly
upward direction, thus pulling said end plate towards worm gear, thereby
resulting in compression of said spring; v. reaching a final vertical upward displacement position for said end plate; and vi. locking said spring wheel using said latch after marginal angular
displacement of spring wheel.

Typically, said step of locking said spring wheel using said latch after marginal angular displacement of spring wheel comprising a step of locking said spring wheel using said latch after 7 degree (of clearance) of angular displacement of said spring wheel.
According to this invention, there is provided a method for energy release using worm and worm wheel drive in an energy storing device, said method comprises the steps of:
A. releasing said latch;
B. decompressing said spring due to release of compressed energy;
C. further angularly displacing said spring wheel, in said first direction, due to
release of said compressed energy, thereby completing a second 180 degree
angular displacement;
D. linearly displacing said shaft / spring rod in an operative vertical linearly
downward direction, thus pushing said end plate away from said worm gear,
thereby resulting in decompression of said spring; and
E. reaching a final vertical downward displacement position for said end plate.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
Figure 1 illustrates a schematic of the closing spring and its associated mechanism for charging, in a circuit breaker mechanism of the prior art.
The invention will now be described in relation to the accompanying drawings, in which:
Figure 2 illustrates a schematic of the worm and worm wheel drive in its discharged state;

Figure 3 illustrates a schematic of the worm and worm wheel drive in its charged state; and
Figure 4 illustrates another schematic view of the worm and worm wheel drive.
DETAILED DESCRIPTION OF THE ACCOMPANYING DRAWINGS
Figure 1 illustrates a schematic of the closing spring and its associated mechanism for charging, in a circuit breaker mechanism of the prior art.
According to this invention, there is provided a worm and worm wheel drive for energy storing device. This energy storage device may be used with switch gear equipment such as circuit breakers.
Figure 2 illustrates a schematic of the worm and worm wheel drive in its discharged state.
Figure 3 illustrates a schematic of the worm and worm wheel drive in its charged state.
Figure 4 illustrates another schematic view of the worm and worm wheel drive.
In accordance with an embodiment of this invention, there is provided a worm gear (23) adapted to be angularly displaced about its central axis, resulting in its rotation. Typically, said worm gear (23) has a defined axis of installation with respect to the entire arrangement and system. A latch (27) is provided which engages with the roller(s) at the circumference of the spring wheel (24) in order to

lock its position. Engagement of this latch depends upon pre-defined engagement parameters in relation to charging position.
In accordance with another embodiment of this invention, there is provided a spring (28) adapted to be placed operatively below said worm gear (23). Typically, said spring (28) is an operative vertical closing spring, which should be compressed in order for storage of energy. This stored energy is released in cases when a circuit breaker is to be operatively actuated.
In accordance with yet another embodiment of this invention, there is provided a drum guide (31), spaced apart from said worm gear (23), adapted to house said spring (28). Typically, said drum envelopes said spring (28) and both have a common axis.
In accordance with still another embodiment of this invention, there is provided an end plate (32) adapted to be located operatively beneath said spring (28). The spring (28) extends operatively downwards to culminate into the end plate (32).
In accordance with still another embodiment of this invention, there is provided a shaft (25) or spring rod (25) with a first end adapted to be coupled, indirectly, to the worm gear (23) and a second end adapted to be connected to the end plate (32). Typically, the axis of the shaft is in line with the axis of the drum guide (31) and spring (28), and hence, laterally offset with respect to the worm gear (23).
In accordance with an additional embodiment of this invention, there is provided a worm element (22) adapted to be driven by a motor (21) for its angular displacement along its angular displacement axis. The worm element (22) engages with the worm gear (23) to form a worm and worm wheel drive element (22, 23).

The motor (21) is connected to worm element (22) through bevel gears. According to one working embodiment, motor (21) angularly displaces in a clockwise direction. So, worm element (22) angularly displaces in an anticlockwise direction (first direction). This in turn drives the worm gear (23) in an anti-clockwise direction (same first direction).
In accordance with another additional embodiment of this invention, there is provided a spring wheel (24) adapted to be co-axially disposed on the worm gear (23). The spring wheel (24) is superimposed on to the worm gear (23). An operative upper end of the spring rod (25) is attached to the spring wheel (24) such that the point of attachment (33) is offset from the centre of said spring wheel. The spring wheel (24) has a first diameter which is relatively lesser in diameter than the worm gear (23). The spring wheel comprises an extended segment such that that the second diameter (taken from the circumference of the extended segment to the non-extended circumference of the spring wheel) is greater than the first diameter of the spring wheel (24) but lesser than the diameter of the worm gear (23). Spring wheel (24) can independently rotate inside the worm gear (23).
In accordance with yet another additional embodiment of this invention, there is provided an eccentric element (26) on the worm gear (23) such that it can come into contact with an edge of the extended segment of the spring wheel (24). This eccentric element (26) is located at the edge of the worm gear (23). When this eccentric element (26) comes in contact with (extended segment of) the spring wheel (24), both, worm gear (23) and spring wheel (24) angularly displace simultaneously as the eccentric element (26) on the worm gear (23) drives (by pushing) the extended segment of the spring wheel (24).

As the worm gear (23) angularly displaces about its axis, the associated shaft (25) linearly displaces up and down, thus pulling the end plate towards worm gear (23), and thereby resulting in compression of the spring (28).
As the worm gear (23) completes a first 180 degree angular displacement, the spring wheel (24) is also angularly displaced along with worm gear (23), so the shaft (25) linearly displaces in an operative vertical linearly upward direction, thereby pulling the end plate (32) with it. Therefore, the end plate (32) works towards compressing the spring (28). The end plate (32) reaches its final vertical upward displacement position.
The charging starts from position shown in Figure 2 of the accompanying drawings. For charging (storing energy in spring), motor (21) starts angularly displacing in clockwise direction. Hence, worm gear (23) angularly displaces in anticlockwise direction. At this position, the extension (26) on worm gear (23) is in contact with the spring wheel (24). So, spring wheel (24) is angularly displaced in anticlockwise direction with worm gear (23). The shaft or spring rod (25) linearly displaces operatively upwards, thereby forcing the end plate (32) to compress the spring (28). This results in spring charging.
After passing vertical position (top side), spring rod (25), due to compression forces acting, helps to angularly displace spring wheel (24) in anticlockwise direction, independently, and so now it rotates independently (no contact between worm gear (23) and spring wheel (24)). After some (marginal) angular displacement of spring wheel (24), it is locked by latch (27).
Preferably, the marginal angular displacement beyond the fully charged position is about 7 degrees (of clearance).

The position shown in Figure 2 of the accompanying drawings illustrates latch (27) locking the spring wheel (24) so that energy remains stored in spring (28). When latch (27) is triggered or released, the spring wheel (24) is angularly displaced in same direction (anticlockwise) due to release of compression forces. This action releases energy from spring and can transfer for charging tripping spring.
The Technical Advancement of this invention lies in providing a worm and worm wheel drive for energy storage such that there is provided a compact design with reduced number of linkages.
While this detailed description has disclosed certain specific embodiments of the present invention for illustrative purposes, various modifications will be apparent to those skilled in the art which do not constitute departures from the spirit and scope of the invention as defined in the following claims, and it is to be distinctly understood that the foregoing descriptive matter is to be interpreted merely as illustrative of the invention and not as a limitation.

We claim,
1. A worm and worm wheel drive for energy storing device, said device comprising:
a) a worm gear adapted to be angularly displaced about its central axis, resulting in its rotation;
b) a worm element adapted to be driven by a motor for its angular displacement along its angular displacement axis;
c) a spring wheel adapted to be co-axially disposed on said worm gear, said spring wheel having a first diameter which is relatively lesser in diameter than said worm gear, said spring wheel further comprising an extended segment such that a second diameter (taken from the circumference of said extended segment to the non-extended circumference of said spring wheel) is greater than said first diameter of said spring wheel but lesser than the diameter of said worm gear;
d) a latch adapted to engage with roller(s) at the circumference of said spring wheel in order to lock its position, said engagement depending upon pre-defined engagement parameters in relation to charging position;
e) a spring adapted to be placed operatively below said worm gear;
f) an end plate adapted to be located operatively beneath said spring, said spring extending operatively downwards to culminate into said end plate;
g) a shaft / spring rod with a first end adapted to be coupled, indirectly, to said worm gear and a second end adapted to be connected to said end plate; and
h) an eccentric element on said worm gear such that it can come into contact with an edge of said extended segment of said spring wheel.

2. The worm and worm wheel drive for energy storing device as claimed in
claim 1 wherein, said worm gear having a defined axis of installation with respect to said device.
3. The worm and worm wheel drive for energy storing device as claimed in claim 1 wherein, said spring is an operative vertical closing spring, adapted to be compressed in order for storage of energy.
4. The worm and worm wheel drive for energy storing device as claimed in claim 1 wherein, said device comprising a drum guide, spaced apart from said worm gear, adapted to house said spring.
5. The worm and worm wheel drive for energy storing device as claimed in claim 1 wherein, said device comprising a drum guide adapted to envelope said spring with both spring and drum guide having a common axis.
6. The worm and worm wheel drive for energy storing device as claimed in claim 1 wherein, said worm element engages with said worm gear to form a worm and worm wheel drive element.
7. The worm and worm wheel drive for energy storing device as claimed in claim 1 wherein, said motor is connected to said worm element through bevel
gears.
8. The worm and worm wheel drive for energy storing device as claimed in
claim 1 wherein, said spring wheel is superimposed on to said worm gear.

9. The worm and worm wheel drive for energy storing device as claimed in claim 1 wherein, an operative upper end of said spring rod is attached to said spring wheel such that the point of attachment is offset from the centre of said spring wheel.
10. The worm and worm wheel drive for energy storing device as claimed in claim 1 wherein, said spring wheel is adapted to independently rotate inside said worm gear.
11. The worm and worm wheel drive for energy storing device as claimed in claim 1 wherein, said eccentric element is located at the edge of said worm gear.
12. A method for energy storage using worm and worm wheel drive in an energy storing device of claim 1, said method comprising the steps of:
i. angularly displacing said worm element, in a first direction, by said
motor; ii. angularly displacing said worm gear, in said first direction, by said worm
element; iii. engaging said eccentric element, on said worm gear, with said extended
segment of said spring wheel in order to simultaneously drive said worm
gear and said spring wheel from an operative bottom position to an
operative top position, thereby completing a first 180 degree angular
displacement iv. linearly displacing said shaft / spring rod in an operative vertical linearly
upward direction, thus pulling said end plate towards worm gear, thereby
resulting in compression of said spring;

v. reaching a final vertical upward displacement position for said end plate;
and vi. locking said spring wheel using said latch after marginal angular
displacement of spring wheel.
13. The method for energy storage using worm and worm wheel drive in an energy storing device of claim 12 wherein, said step of locking said spring wheel using said latch after marginal angular displacement of spring wheel comprising a step of locking said spring wheel using said latch after 7 degree (of clearance) of angular displacement of said spring wheel.
14. A method for energy release using worm and worm wheel drive in an energy storing device of claim 1, said method comprising the steps of:
A. releasing said latch;
B. decompressing said spring due to release of compressed energy;
C. further angularly displacing said spring wheel, in said first direction, due
to release of said compressed energy, thereby completing a second 180
degree angular displacement;
D. linearly displacing said shaft / spring rod in an operative vertical linearly
downward direction, thus pushing said end plate away from said worm
gear, thereby resulting in decompression of said spring; and
E. reaching a final vertical downward displacement position for said end
plate.

Documents

Name Date
Form 18 [27-09-2016(online)].pdf 2016-09-27
Form-18(Online).pdf 2018-08-11
ABSTRACT1.jpg 2018-08-11
2858-MUM-2012-FORM 3.pdf 2018-08-11
2858-MUM-2012-Power of Attorney-190116.pdf 2018-08-11
2858-MUM-2012-FORM 2[TITLE PAGE].pdf 2018-08-11
2858-MUM-2012-CORRESPONDENCE.pdf 2018-08-11
2858-MUM-2012-FORM 1(15-3-2013).pdf 2018-08-11
2858-MUM-2012-FORM 1.pdf 2018-08-11
2858-MUM-2012-DRAWING.pdf 2018-08-11
2858-MUM-2012-CORRESPONDENCE(15-3-2013).pdf 2018-08-11
2858-MUM-2012-Correspondence-190116.pdf 2018-08-11
2858-MUM-2012-ABSTRACT.pdf 2018-08-11
2858-MUM-2012-FORM 2.pdf 2018-08-11
2858-MUM-2012-CLAIMS.pdf 2018-08-11
2858-MUM-2012-FER.pdf 2019-06-26
2858-MUM-2012-DESCRIPTION(COMPLETE).pdf 2018-08-11
2858-MUM-2012-AbandonedLetter.pdf 2020-01-30

Orders

Applicant Section Controller Decision Date URL