FIELD OF INVENTION
[001] The present invention relates to the field of mounting means of electrical/electronic devices on din rail. The present invention more 5 particularly relates to an improved bi-stable snap-pusher for mounting of an electrical/electronic device on din rail.
BACKGROUND/PRIOR ART
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[002] In prior art several kind of snap-pushers have been proposed. Some of them require the user to pull a latch downwards continuously by a tool to disengage the locking, and simultaneously lift the device from din-rail. Such locking features usually require an excessive force as the device is pulled against the spring force, and also the user is 15 required to hold the device until it is removed from din-rail. Other kind of snap-pushers have spring action only due to plastic part of design which may be insufficient to lock the device properly, especially if din-rail is of slightly deviated size. This renders the known snap-pushers inefficient. 20
[003] Now, reference may be made to some prior patents hereinunder.
[004] Publication No. US9312667 (B2) discloses a device for locking to a DIN rail including a shaft defining an axis of rotation and first and 25 second rail-engaging members connected to the shaft. The rail-engaging members are each shaped to engage a DIN rail in a respective
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engaging position. The shaft is rotatable about the axis of rotation and thereby arranged to urge each rail-engaging member into its respective engaging position with a DIN rail positioned between the first and second rail-engaging members. Shaft portion may first be inserted through a spring before being passed through threaded bore. 5 Spring rests in spring guide and one end engages with lock whilst the other engages with guide.
[005] Publication No. EP1037347 (A1) is directed to a fixing device that has an opening on the attachment surface of the electrical unit 10 and a sprung synthetic sliding element that can be pressed into the opening that engages behind a longitudinal edge of the main profile bearer rail when latched in. The sliding element has an elongated sliding body with protruding spring arms that engage housing apertures to press the sliding element against the rail and a protrusion 15 for limiting inward movement when not installed.
[006] Publication No. US2002136599 (A1) is related to an electrical device that can be snapped onto a support rail by means of a compression spring orthogonal to the length of the rail and arranged 20 in a cylindrical housing. The housing opens to the outside, opposite the edge of the rail, via an opening adapted to the insertion of the spring during its assembly and comprises an elastic wall capable of transversal movement. Said wall comprising a bearing surface on the rail edge side on which the spring is buttressed or another similar 25 bearing surface that can be activated after the insertion of the spring.
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[007] Publication No. EP0451723 (A1) is pertinent to a quick fixing device to snap a line protection switch onto a hat-profile rail having a fixed tab and a movable tab, the latter of which is integrally formed on a slide. Located between the slide and the housing of the line protection switch is a helical compression spring which, in the first 5 position of the slide, is pressed into a first stable position, in which the slide is pressed against the hat-profile rail. The slide can be displaced from the first position into its second position (and back), in which the helical compression spring passes beyond a dead-point position and assumes a second stable position in the second position of the slide. 10
[008] Publication No. US2004115977 (A1) pertains an electric device with a modular construction, comprising at least one module, preferably several modules. Said module(s) is fixed onto a mounting rail. To mount or dismount a module in a simple manner, 15 the module is fixed onto the mounting rail using an adapter. Said adapter fulfils its fixing function by means of a bistable snap-on process.
[009] Publication No. EP2498353 (A1) discloses an appliance having a 20 fixation clamp including a carriage slidably mounted on a body of the appliance by a chassis, between raised and lowered positions. A latch of the carriage and the body are configured such that the carriage is locked against the body in raised position when the latch is in a rest position, and released from the body when the carriage is in raised 25 position and the latch is in bent position. A slide is separated from the carriage and slidably mounted in the carriage, where an upper end of the slide forms a lower jaw maintained on a horizontal support rail.
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[0010] However, none of the above can fulfill the requirements of the present invention, for which it is devised.
[0011] Hence the present invention has been proposed so as to provide a new and cost-effective bi-stable snap pusher such that it results in 5 better performance during mounting with application of very less force in the course of demounting. Further, it works efficiently by holding the circuit-breaker even on din-rails having slight deviations from standard size.
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OBJECTS OF THE INVENTION
[0012] The principal objective of the present invention is to provide an improved bi-stable snap pusher for mounting of an electrical/electronic device on din rail which leads to better 15 performance during mounting condition with requirement of very less force during demounting.
[0013] Another object of the present invention is to provide an improved bi-stable snap pusher for mounting of an electrical/electronic device 20 on din rail which works efficiently by holding the circuit-breaker even on din-rail having slight deviations from standard size.
[0014] Yet another object of the present invention is to provide an improved bi-stable snap pusher for mounting of an 25 electrical/electronic device on din rail which is cost effective.
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[0015] Still another object of the present invention is to provide an improved bi-stable snap pusher for mounting of an electrical/electronic device on din rail which is easy to assemble.
SUMMARY OF THE INVENTION 5
[0016] The present invention introduces an improved bi-stable snap-pusher for mounting of an electrical/electronic device on din rail. The bi-stable snap-pusher is provided with base and guide with a metallic spring resting between the same. So that devices can be easily 10 mounted and removed from din rail with less force requirement from the user. They efficiently hold onto the din-rail in installed position. Further, the spring force is sufficient to hold onto the din-rail efficiently, even if din-rail is slightly deviated from its standard size.
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BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
[0017] Further objects and advantages of this invention will be more apparent from the ensuing description when read in conjunction with the accompanying drawings of the exemplary embodiments and wherein: 20
Figure 1 shows: The rear view of MCB to be mounted on din-rail by means of snap-pusher of the present invention.
Figure 2 shows: Snap-pusher according to the present invention.
Figure 3 shows: Snap-pusher base part of the invention. 25
Figure 4 shows: Latching member part of snap pusher base and parts thereof.
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Figure 5 shows: Snap-pusher guide part as per the present invention.
Figure 6 shows: Rear view of snap-pusher guide part of the invention.
Figure 7 shows: Rear view of snap-pusher according to the present 5 invention.
Figure 8 shows: Locking teeth of guide engaged with the lower flange of the din-rail in accordance with the present invention.
DETAIL DESCRIPTION OF THE PRESENT INVENTION WITH 10 REFERENCE TO THE ACCOMPANYING DRAWINGS
[0018] The present invention is pertinent to an improved bi-stable snap-pusher for mounting of an electrical/electronic device on din rail. The din rail has two abutment flanges, laterally spaced opposite to 15 each other in order to support the mounting of devices such as MCB.
[0019] The MCB which is to be mounted on din-rail by snap-pusher comprises of two chassis covers; namely front and back. For the rear face of MCB, reference may be made to figure 1. The bottom corner 20 edges of both chassis covers have a flat cut 1 and a tapered part 2. The rear surface also has a projection 3 which is identical on both the chassis covers. To engage with the upper flange of din-rail, MCB chassis is provided with recess portion 4. For fitting snap-pusher on electrical device, the snap-pusher is pushed down until it is locked by 25 press-fitting action, thereafter it slides along the MCB edges until its walls meet the end 5.
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[0020] Referring to the figure 2, the snap-pusher according to the present invention includes base (100), guide (200) and metallic spring (300), wherein the base and guide both are made of resin preferably thermoplastic material without restricting ambit of the invention to the same. Thus, other materials readily apparent to a person skilled in the 5 art are understood to be within scope of the invention. There is provision of a central leg (111, 203) placed coaxially with the base and guide respectively. The spring (300) rests in between central leg (111) of base and central leg (203) of guide (200). Thus it is guided from both sides. This results in the stable spring’s assembly and design, making 10 it difficult to dislocate during operation.
[0021] Referring to the figure 3, said snap-pusher base (100) comprises of mounting flanges (101) on both sides disposed in parallel maintaining a gap therebetween. The inner sides of mounting flanges 15 constitute a tapered projection (102), which is inclined towards the central axis of snap-pusher.
[0022] Typically, in installed position the tapered surface (102) of said snap-pusher slides along the tapered part 2 of MCB edges and the 20 stepped projection 3 on MCB rear surface slides along lower part (103) of tapered projection (102). The base further has a latching member (104), inclined at an angle having a fixed hinge (105) about which it rotates. The latching member possesses elastic properties and springing action to facilitate operations. When the downward pressing 25 force is removed, it reverts to its original position. The latching member has a projecting part (dimple) (106) responsible for locking and unlocking, which projects downwards and is having a chamfer. So
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that when latching member is pressed inwards, it slips very gently over and beyond the projection 3 provided on device and brings snap-pusher to disengaged position. When snap-pusher is pushed up to working position, the projecting part (106) slides over the projection 3 on MCB. The latching member has a slanted part (107) having a hole 5 (108) and a protrusion (109) as shown in figure 4 serving as a space and support for a tool such as screw driver respectively. Electrician presses and pulls latching member by screw-driver if it cannot be reached by hand. The base has a plurality of legs (110) perpendicular to longitudinal axis of snap-pusher, which are lifted from the base. 10
[0023] For the guide (200), reference may be made to figure 5 and 6. It has five legs including two outer legs (201), two inner legs (202) and one central leg (203), co-axial with the leg (111) on the base. The outer two legs (201) have locking teeth (204) on front side at extreme end 15 thereof and (205) on rear side at intermediate portion thereof. It also has locking teeth (206) as in figure 8.
[0024] As discussed, the spring 300 is positioned between central legs (111, 203) of base and guide forming an efficient design as the spring 20 is properly guided from both sides, which in turn avoids any chances of the same getting dislocated during operation. The guide is slided over the base and gets fitted by snap-action. The outer legs (201) get slided under the legs (110) of base and get snap-fitted, with assistance from the locking teeth (204). 25
[0025] Further, referring to the figure 7, the base has cuts (112) on rear side and the fitment of guide with base is further supported as the
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locking teeth (205) on guide get engaged with the cuts (112) on base. The inner legs support in guiding the movement of guide in a stable manner and act as stopper in most compressed position of spring.
[0026] Furthermore, the invention provides more cost effective design. 5 The moulding material in latching member can be economized, as it does not have to support spring.
[0027] The bi-stable snap-lock according to the present invention has two locking positions: the lower or disengaged position, and the upper 10 or working position as shown in Figure 8. In upper position, the locking teeth (206) of guide are engaged with the lower flange of the din-rail. The spring (300) is compressed, and applies force in direction such that snap-pusher holds onto the din-rail efficiently. This is an advantage if din-rail is of slightly different dimensions (due to different 15 designers/manufacturing errors), say of slightly increased length as compared to the standard size, as the spring force is sufficient to appropriately mount the breaker.
[0028] Mounting can be carried out in two ways, either by engaging the 20 recess 4 of MCB with upper flange of din rail followed by rotating the MCB and pressing onto the din rail. This engages the locking teeth (206) with the lower flange of the din rail.
[0029] Other method is by engaging the recess 4 of MCB with the upper 25 surface of the din rail with snap pusher at disengaged position, then the snap pusher is dragged upwards so as to lock it in working position.
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[0030] In certain prior-arts, the latching member is pulled against the spring force which is acting in opposite direction on din-rail. This requires an excessive force on part of the user. In contrast the proposed design has an advantage that during demounting, user has 5 to apply minimal bending force. The latching member simply needs to be pressed inwards (to remove the interference caused by dimple). This simultaneously releases the spring force which is developed in the snap-pusher assembly and acting on din-rail. Thus the snap-pusher can be pulled to disengaged position. 10
[0031] The present invention is also associated with further advantage. For instance during demounting, the latching member is pressed inwards so as to remove the interference caused by projecting part/dimple (106) and is then dragged downwards to disengage the 15 locking teeth from din-rail. The complete MCB can now be moved upwards so as to remove it from din rail without disturbing any adjacent MCBs and without removing the incoming side bus bar.
[0032] Though the invention is explained by means of MCB for 20 understanding. However, it can be implemented to mount any electrical/electronic device on din-rail.
[0033] The user can replace a circuit breaker from a series of circuit breakers mounted on din rail and connected with a bus bar on 25 incoming side, without disturbing any other circuit breaker and/or their electrical connections and without removing the bus bar as well.
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Advantageous Features
– Improved performance during mounting with requirement of very less force during demounting.
– Works efficiently by holding the electrical/electronic device even on din-rail having slight deviations from standard size. 5
– Cost effective.
– Easy to assemble.
– No requirement of pulling the latch persistently for removal of device from the din-rail.
– Installer needs not to use a tool to forcibly disengage the din-10 clip from din rail flanges.
– Allows removal of device from din rail by using a tool in case the latching member cannot be accessed by hand.
– Stable assembly and design of snap pusher, which cannot be disturbed by mis-handling. 15
[0034] It is to be noted that the present invention is susceptible to modifications, adaptations and changes by those skilled in the art. Such variant embodiments employing the concepts and features of this invention are intended to be within the scope of the present 20 invention, which is further set forth under the following claims:-

WE CLAIM:
1. An improved bi-stable snap-pusher for mounting of an electrical/electronic device on din rail comprising of a base and guide with a spring therebetween, wherein the base comprises atleast two abutment flanges laterally spaced 5 opposite to each other with a latching member therebetween and said guide is having a plurality of legs, in which a central leg is placed co-axially with the central leg of base.
2. An improved bi-stable snap-pusher for mounting of an 10 electrical/electronic device on din rail as claimed in claim 1, wherein the spring rests between the central leg of said base and guide for being guided from both sides in a stable manner, in which the base has multitude of legs orthogonal to longitudinal axis thereof. 15
3. An improved bi-stable snap-pusher for mounting of an electrical/electronic device on din rail as claimed in claim 1 or 2, wherein the flanges, inner sides of which constitute a tapered projection inclined towards the central axis of the 20 snap-pusher.
4. An improved bi-stable snap-pusher for mounting of an electrical/electronic device on din rail as claimed in any of the preceding claims wherein the latching member forms an 25 inclined member having a fixed hinge of rotation, which possesses elastic properties and springing action.
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5. An improved bi-stable snap-pusher for mounting of an electrical/electronic device on din rail as claimed in claim 4 wherein the latching member is provided with a projecting part for locking and unlocking, which projects downwards and is having a chamber. 5
6. An improved bi-stable snap-pusher for mounting of an electrical/electronic device on din rail as claimed in any of the preceding claims wherein the latching member has a slanted part having a hole and a protrusion forming a space 10 and support for the tool respectively.
7. An improved bi-stable snap-pusher for mounting of an electrical/electronic device on din rail as claimed in any of the preceding claims wherein said plurality of legs of the 15 guide include two outer legs, two inner legs and the central leg, in which each of the outer legs is having locking teeth on front side at extreme end thereof and on rear side at intermediate portion thereof together with another locking teeth. 20
8. An improved bi-stable snap-pusher for mounting of an electrical/electronic device on din rail as claimed in any of the preceding claims wherein said locking teeth of the outer legs get snap-fit with the perpendicular legs on the base and 25 said another locking teeth of the guide are engaged with the lower flange of din rail, and wherein the inner legs support
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stable movement of guide and act as stopper in most compressed position of spring.
9. An improved bi-stable snap-pusher for mounting of an electrical/electronic device on din rail as claimed in any of 5 the preceding claims wherein said base has cut on rear side thereof for engaging with the locking teeth on rear side of the guide.
10. An improved bi-stable snap-pusher for mounting of an 10 electrical/electronic device on din rail as claimed in any of the preceding claims is associated with the advantageous features such as herein described.