FORM 2
THE PATENTS ACT, 1970
COMPLETE SPECIFICATION
(See Section 10)
MODULE LOCKING GUIDE
Numbered as dated
INVENTOR:
a) NILESH KAMALA PRASAD VARMA
APPLICANT:
LARSEN & TOUBRO LIMITED
L&T House, Ballard Estate, P.O. Box No. 278,
Mumbai 400 001, Maharashtra
INDIA.

MODULE LOCKING GUIDE
Technical field of the invention:
[0001] The present invention generally relates to the draw-out module locking and guiding device. More particularly it relates to the modular construction which is independent of the draw-out and panel assembly to achieve smooth draw-out mechanism with the provision of locking and unlocking the module.
Background of the invention:
[0002] The switchgear is a common name used for metal-enclosed power circuit breaker. The metal enclosed switchgear assembly is completely enclosed on all sides and top with sheet metal and contains stationary primary power circuit switching or interrupting devices with buses and connections. The switchgear generally contains circuit breakers of removable or rack out types and are contained in an individual grounded metal compartments. These Metal-enclosed switchgears are used in electric power distribution systems for the control and protection of circuits and equipment.
[0003] The circuit breakers found in switchgear, distribution centers, and service entrance equipments are of three types: molded case circuit breakers, insulated case circuit breakers, fixed or draw-out power circuit breakers. In an electrical power distribution field, draw-out type voltage circuit breakers are quite large and are usually housed in corresponding circuit breaker cells of switchgear. Some mechanical means, such as racking devices, are employed to rack-in or withdraw these large circuit breakers.


[0004] In certain types of low-voltage distribution switchboard and power assemblies it is frequently necessary to mount the individual circuit breakers within a protective metal enclosure in such a manner that the breakers can be drawn out of engagement with the panel board for replacement or test purposes and then be returned to its original connected position in a convenient and positive manner.
[0005] Switching devices are usually mounted on the front of the unit door so that the breaker can be removed or inserted without damaging a relay. Guide rails are provided so that the breaker will roll into proper position in the cubicle. The mechanism insures perfect alignment when the breaker is racked into its operating position. The guide rails are provided for racking out or removing breakers from an integral part of the cubicle. It provides a heavy duty rail to positively prevent breaker from rolling off the guide rail. The guide rails are necessary to ensure safe and aligned movement of the modules while racking it in and out, to avoid misalignment of the moving contact.
[0006] Circuit-breaker mounting assembles are equipped with a racking mechanism that properly positions the power circuit breaker and holds it rigidly in connected, test, and fully disconnected positions. The breaker modules are generally accessible for removal and replacement. The draw out modules should have manually actuated locking devices to prevent inadvertently while withdrawing the module from a compartment. The circuit breakers are provided with an integral racking mechanism. The breaker racking mechanism allows smooth and consistent breaker movement.
[0007] There are several mounting styles for panel boards and switchgear. Some devices are mounded on poles or racks. The draw out position of the assembly comprises a pair of guide rails and a pair of drive rails that are secured to the back of the circuit breaker housing.


[0008] The module locking using the guide rails uses metallic inserts, which require regular lubrication. It also results in scrapping of the external paint coating during regular alignment.
[0009] Hence there is a need to develop an improved locking and guiding device to replace the conventional bulky and costly rail mechanism for the draw-out modules.
[0010] Prior art discloses a draw out mechanism conventionally used comprised of a pair of bulky rail assembly with the racking nut for locking the module being screwed to the tray and rails being loaded with spring ball mechanism. All these summed up to form a costly and bulky mechanism. Also lubricating the rails added to the additional labour and input to the assembly functioning. Hence, it was not possible to use this in the panel where the matrix ideology of forming the panel with draw-out modules asked for the compact and light mechanism such that it can work even in cold or hot conditions where the lubricants used may either freeze out or melt respectively.
[0011] Hence there is a need to achieve smooth draw-out mechanism within the least available space, with a provision of locking and unlocking the module and at the same time to avoid the lubrication without affecting the functionality of the component. Hence there is a need to develop an improved locking and guiding means for the draw-out modules and to replace the conventional bulky and costly rail mechanism.
Objects of the invention:
[0012] The primary objective of the invention is to develop a module locking guide base to achieve smooth draw out mechanism in the least available space along with a provision of locking and unlocking the circuit breaker module into the panel matrix.


[0013] An additional objective of the invention is to design a draw-out module locking guide with final locking using racking nut.
[0014] Yet another objective of the invention is to develop a module locking guide base with metallic insert to avoid lubrication of the metallic inserts.
[0015] Yet another objective of the invention is to eliminate the conventional bulky and costly rail assembly for draw-out modules.
[0016] Yet another objective of the invention is to design a Module Locking Guide which is compact and light weight and can be easily handled to provide smooth guiding mechanism.
[0017] Yet another objective is to provide gradual engagement of the electrical contacts thereby avoiding impact loading.
[0018] Yet another objective of the invention is to develop a module locking guide which is independent of the draw-out module or panel assembly.
SUMMARY OF THE INVENTION:
[0019] The above discussed and other drawbacks and deficiencies of the prior art are overcome or alleviated by a module locking guide base to achieve smooth draw out mechanism.
[0020] The present invention generally relates to switchgear devices. It deals with draw-out module guiding/racking mechanism and draw-out module locking guide. The draw-out module is independent of the module locking guide to provide smooth racking


mechanism. The Module Locking Guide is used to guide the module or draw-out feeder comprising of circuit breaker and other electrical components integral to the module. The purpose of the component is to achieve smooth draw out mechanism in the least available space along with a provision of locking and unlocking the module into the panel matrix. The Module Locking Guide is a simple module guiding component along with a final locking using racking nut.
[0021] According one embodiment of the invention the draw out module assembly to be guided consists of a sheet metallic fabricated module or other module design. It houses electrical equipments and has a through slot at the bottom. The module being a moving assembly slides into the two side grooves of the Module Locking Guide. The module locking guide is fixed on the tray assembly through two countersunk screws and one small cylindrical protrusion.
[0022] According to one embodiment of the invention the module locking guide consists of an integral metallic insert which gets aligned with the racking screw. Racking screw being the integral part of the module. In order to avoid any hazards during module maintenance the entire length of the insert is provided with integral threads and the racking screw is provided with external threads. Both are positioned in such a way as to obtain sufficient clearance between the electrical contacts at the rear end or at the side of the module. This helps one to be fully safe while module is drawn out for maintenance.
[0023] According to another embodiment of the invention the material used for module locking guide base is a Nylon-66 with glossy black colour, whereas Integral insert is made of Stainless Steel of the Grade AISI - 304. Nylon-66 material is used to avoid greasing on the sliding portion and scrapping of the paint on the module. Stainless steel material is used to avoid corrosion and to give sufficient strength. The insert is


formed as an integral part of Module Locking Guide during manufacturing of the final component in the molding process.
[0024] According to one embodiment of the invention the draw-out moving assembly is initially placed at the opening of the Module Locking Guide such that the slot at the bottom of the module base frame gets engaged with the two side by side horizontal slots/grooves in the Module Locking guide. This is followed by a manual push to the module assembly such that it just gets the racking screw aligned properly with the insert in the 'Module Locking Guide'.
[0025] The draw out module slides into the locking guide through the racking action of the racking screw into the racking nut of Module Locking Guide'. The draw-out module can be similarly racked out by the by the reverse racking action of the racking screw thereby serving the locking and unlocking along with the alignment of the module assembly into the panel matrix.
BRIEF DESCRIPTION OF THE DRAWINGS:
[0026] Figure 1 shows a wire frame view of the 'module locking guide' with metallic insert.
[0027] Figure 2 shows a solid view of the module locking guide base with metallic insert.
[0028] Figures 3 illustrate the module locking guide and insert assembly.


[0029] Figure 4 shows the metallic insert that is to be inserted in to the module locking guide
[0030] Figure 5 illustrate the wire frame view of the module locking guide and insert assembly from different views.
[0031] Figure 6 shows the unmounted tray assembly.
[0032] Figure 7 illustrates integral modular screw arrangement with a cylindrical protrusion.
[0033] Figure 8 shows two side by side horizontal slots at the bottom of the sheet metallic module with module guide being inserted in to the slot.
[0034] Figure 9 illustrates the sliding of the module and the start of engagement of the racking screw with the module locking guide and the integral insert.
[0035] Figure 10 illustrates the final engagement of module with the tray assembly.
[0036] Figure 11 illustrates the final engagement of the racking screw with the integral insert in the guide base.
DETAILED DESCRIPTION OF THE EMBODIMENTS:
[0037] Figure 1 shows a disassembled view of module locking guide which comprises of module locking guide base (102) along with insert (106). It shows a wire


frame view of the module guide. Insert (106) which is shown separately in Figure 1 is to be inserted in to cylindrical hole (104) provided in module locking guide base (102). The Module Locking Guide is basically used to guide module (704, Figure 7) or draw-out feeder comprising of circuit breaker and other electrical components integral to the module (704, Figure 7).
[0038] Figure 2 shows a solid view of module locking guide base (102) with insert (106). The material used in module locking guide base (102) is a Nylon-66 which comprises of 30-50% of glass fiber, where as the percentage of the fiber glass used depends on strength and finish required. Module locking guide base (102) is made glossy black in colour. Nylon-66 material is used for the module locking guide to avoid greasing on the sliding portion and scrapping of the paint on the module. Integral insert (106) is made of Stainless Steel of Grade AISI - 304. Insert (106) is formed as an integral part of Module Locking Guide (102) during manufacturing of the final component in molding process. The stainless steel is used as a material for manufacturing integral insert (106) to avoid corrosion and to provide sufficient strength. The two grooves on the insert help in proper manufacturing and gripping of the insert in the final 'Module Locking Guide'.
[0039] Figure 3 and 4 shows the individual module locking guide (102) and the integral insert (106) separately. Module Locking Guide (102) is used to guide the module or draw-out feeder (704, Figure 7) comprising of circuit breaker and other electrical components integral to the module. The main purpose of using module locking guide (102) is to achieve smooth draw out mechanism in the least available space along with a provision of locking and unlocking module (704, Figure 7).
[0040] Figure 5 shows the wire frame view of the module locking guide (102) and insert (106) assembly form different views. Figure 6 shows the module locking guide base (102) with integral insert (106) mounted on the base tray (604). Two mounting screws (602A) and (602B) are used to mount the locking guide (102) with base tray

(604). The entire assembly with module locking guide and the tray provides smooth draw out mechanism for the switchgear or draw-out module (704, Figure 7).
[0041] Figure 7 illustrates integral modular screw (702) arrangement with a cylindrical protrusion. During unlocking and racking out of the assembly there are chances as to some electrical faults can occur, hence to avoid any hazard during module (704) maintenance the threaded length of the insert (106) with integral threads or racking screw (702) with external threads or both is so kept as to obtain sufficient clearance between electrical contacts at the rear end or at the side of the module. This helps one to be fully safe while module (704) is drawn out for maintenance. Figure 7 illustrates a perspective view of the module (704) that is to be guided along with the module locking guide assembly. The module locking guide assembly is placed on the tray (604) which helps in racking the module. The draw out module can be similarly racked out by the reverse racking action of the racking screw (702) thereby serving the locking and unlocking along with the alignment of the module assembly into the panel matrix. The draw out module assembly (704) to be guided consists of a sheet metallic fabricated module or other module design. It houses electrical equipments with a through slot (802) at the bottom of the sheet metallic module. This module (704) being a moving assembly slides into the two side grooves of the Module Locking Guide which is fixed on the tray assembly through two countersunk screws and one small cylindrical protrusion (702).
[0043] Figure 8 shows an opening slot (804) at the bottom of the draw-out module (704). The draw-out module (704) to be guided is placed at front of the module locking guide assembly. The module (704) being a draw-out moving assembly is initially placed at the opening (804) of the 'Module Locking Guide' such that the slot (802) at the bottom of the module base frame gets engaged with the two side by side horizontal slots or grooves in the 'Module Locking Guide'. Once the module (704) is aligned with the locking guide (102), it is followed by a manual push to the module assembly such that it


just gets the racking screw (702) aligned properly with the insert (106) in the 'Module Locking Guide' (102).
[0044] Figure 9 shows the sliding of the module (704) and the start of the engagement of the racking screw (702) with the module locking guide (102) and insert (106). The module being a moving assembly slides into the two side grooves of the Module Locking Guide which is fixed on the tray assembly through two countersunk screws and one small cylindrical protrusion. The draw-out module slides into the guide (102) through the racking action of the racking screw into the racking nut of Module Locking Guide1.
[0045] Figure 10 and 11 show the final engagement of the module (704) with the tray assembly. This assembly offers compact and light mechanism, such that it can work even in cold and hot conditions where the lubricants used may either freeze out or melt respectively. Further the guide is so designed as to maintain the sufficient clearance between electrical terminals while it is drawn out of the switchboard for maintenance.
[0046] Hence it is one of the objectives of the invention to achieve smooth draw out mechanism in the least available space along with a provision of locking and unlocking the module into the panel matrix. At the same time it avoids the lubrication required without affecting the functionality of the component. According to the preferred embodiment of the invention the module locking guide also helps in the precise alignment of the male terminal of the contact on the draw-out module with female terminal of the contact on fixed panel assembly. It also encourages the gradual engagement of the electrical contacts thereby avoiding impact loading.


CLAIMS:
What is claimed is:
1. A module locking and guiding device comprising of a module locking guide base and a stainless steel insert wherein said device is a molded assembly, wherein said stainless steel insert forms the inner screw/nut arrangement in the module locking guide base at the front part of the assembly so as to facilitate the locking, unlocking and racking of the draw-out module.
2. The device of claim 1, wherein said module locking guide base has two horizontal grooves, one on each side of the component, wherein said grooves facilitate movement of the draw-out module assembly.
3. The locking device of claim 1, wherein said movable draw-out module to be guided can be a sheet metallic fabricated module having a through slot at the bottom and housing some basic electrical equipments.
4. The locking device of claim 1, wherein said movable draw-out module to be guided further comprises of modular racking screw arrangement wherein said modular racking screw arrangement facilitates the racking-in and racking-out of said movable draw-out module into fixed panel assembly, wherein said panel assembly comprises of mechanical structure along with electrical bus-bar


arrangements and wiring arrangement, wherein said panel assembly further comprises of fixed and movable electrical modules.
5. The locking device of claim 1, wherein said module locking guide is fixed on a tray in the panel assembly by two countersunk screws wherein said tray is sheet metallic plate with the two longitudinal ribs and fixing arrangement for the module locking guide.
6. The device of claim 1, wherein said molded locking guide base further consists of two side grooves and one small cylindrical protrusion.
7. The device of claim 1 further comprises of two countersunk holes for its fixing to the tray in said panel assembly wherein said cylindrical protrusion at the bottom facia ensures proper positional fixing of said module locking guide on said tray.
8. The locking device of claim 1, wherein said movable draw out assembly is pushed inside said fixed panel assembly in order to be guided through the side grooves in said module locking guide so as to get racked into the insert of said module locking guide by the racking action of said racking screw arrangement.
9. The locking device of claim 1, wherein said movable assembly of draw out module can be racked out from fixed panel by the reverse racking action of the racking screw thereby serving the locking and unlocking along with the alignment of said movable draw out module assembly with the fixed panel assembly.


10. A device of claim 1, wherein said molded base is non-metallic with a stainless steel insert so as to avoid use of lubrication in movement of module and corrosion-less action of the screw.


ABSTRACT:
The invention deals with draw-out module guiding/racking mechanism and draw-out module locking guide. The Module Locking Guide is used to guide the module or draw-out feeder comprising of circuit breaker and other electrical components integral to the module. The purpose of the component is to achieve smooth draw out mechanism in the least available space along with a provision of locking and unlocking the module into the panel matrix. The module locking guide consists of an integral metallic insert which gets aligned with the racking screw. In order to avoid any hazards during module maintenance the entire length of the insert is provided with integral threads and the racking screw is provided with external threads. Both are positioned in such a way as to obtain sufficient clearance between the electrical contacts at the rear end or at the side of the module. This helps one to be fully safe while module is drawn out for maintenance.