WO2016038561A2

WO2016038561A2 - Enhanced switch assembly

Info

Publication number: WO2016038561A2
Application number: PCT/IB2015/056930
Authority: WO
Inventors: Arun Kumar ARORA; Manoj Kumar JINDAL
Original assignee: MINDARIKA PRIVATE Ltd
Current assignee: MINDARIKA PRIVATE Ltd
Priority date: 2014-09-10
Filing date: 2015-09-10
Publication date: 2016-03-17
Anticipated expiration: 2017-03-10
Also published as: WO2016038561A3; IN2014DE02593A

Abstract

The present invention describes an electromechanical switch of a vehicle. Particularly, the present invention describes a contactless electromechanical switch assembly. The electromechanical switch assembly comprises a casing and a housing forming an encapsulation to accommodate a resiliently loaded magnet sub-assembly which is slidably supported on one or more guiding tracks formed in the housing. The magnet sub-assembly comprises an adapter and a socket accommodating a magnet. The electromechanical switch assembly also comprises a PCB assembly is accommodated in the housing and comprises one or more Hall sensors adapted to detect change in magnetic flux due to movement of the magnet sub-assembly, thus providing signal indicative of activation of brake light, cruise control etc.

Description

ENHANCED SWITCH ASSEMBLY

FIELD OF THE INVENTION

The present invention relates to an electromechanical switch assembly of a vehicle. Particularly, the present invention relates to a contactless electromechanical switch assembly for switching ON/OFF of functions like stop lamp, cruise control, etc., more particularly, the present invention relates to a magnet sub assembly of a contactless electromechanical switch assembly.

BACKGROUND OF THE INVENTION

Generally electromechanical switch assemblies are widely used in automobiles for switching (ON/OFF) various functions such as stop lamp function, cruise control function, etc. In contactless switches, one or more magnets are essentially required to del iver sufficient magnetic flux density to sensing element such as hall element or magneto resistive element or the like.

In the existing method, the magnetic part without magnetization is first assembled with the moving part by insert molding and thereafter magnetization is performed of the magnetic material. This process requires special purpose magnetization machines and tedious process control for magnetic properties and also a huge investment on equipment and operating cost.

JP5 194860 describes a method of magnet assembly with moving part wherein a magnet is snap locked directly with the moving part made of insulating resin. The locking of magnet is performed with a single lock only and further for the said lock to be flexible enough, both side of snap have been relieved and furthermore relieving height is more than half of the magnet length. In this case magnet will be press fitted in the three internal sides of the magnet holding part. This leads to weak holding of magnet in moving part. The problem with this type of method of magnet assembly with moving part is tilting of the magnet towards the snap lock due to flexibility of snap lock which provides less support to magnet with the wall aligning to snap lock due to height relief of that wall both side of snap lock. When magnet is tilted, it leads to insufficient magnetic flux to the sensor or hall element resulting in variation in switching point.

Another problem with this existing method of magnet assembly with moving part is that lock overlapping between lock and magnet is very small so as to hold the magnet firmly. This locking is between magnet having smooth surface and moving part (slider) having smooth finish. The said single lock provided herein can slide over the smooth surface of magnet under peak vibration condition and locking between the magnet and moving part can be partially or completely damaged resulting in the magnet falling down due to severe vibration condition. Thus, the prime function of said switch assembly would have failed.

SUMMARY OF THE INVENTION

The present invention provides an electromechanical switch comprising a casing comprising a hollow region and adapted to receive housing. The housing comprising an exterior and an interior, defined by a bottom wall, a top wall, two opposite side walls, a closed end wall and an open end. A resiliently loaded magnet sub-assembly accommodating a magnet disposed in the housing under a force of a spring, being slidably supported on one or more guiding tracks formed in the interior of the housing. The magnet sub assembly comprising an adapter and a socket accommodating a magnet. The socket is adapted to be fitted in a corresponding cavity in the adapter. The adapter comprising a cavity to receive the socket and a plurality of projections extending laterally towards the opposite side walls and the bottom wall of the housing. The switch comprises an actuating shaft having a proximal end being disposed in the interior of the housing so as to remain in contact with the magnet sub-assembly; and a distal end operatively coupled with brake pedal so that movement of the brake pedal causes actuation of the actuating shaft thereby allowing movement of the spring loaded magnet sub-assembly in longitudinal direction. The switch comprises a PCB assembly accommodated in the housing. The PCB assembly comprises one or more Hall sensors adapted to detect change in magnetic flux due to movement of the magnet sub-assembly and to provide signal indicative of activation of brake light and deactivation of cruise control etc.

BRIEF DESCRIPTION OF FIGURES

Further aspects and advantages of the present invention will be readily understood from the following detailed description with reference to the accompanying figures of the drawings. The figures together with a detailed description below, are incorporated in and form part of the specification, and serve to further illustrate the embodiments and explain various principles and advantages but not limiting the scope of the invention. In the accompanying drawings,

Figures 1 and 2 illustrate an electromechanical switch assembly according to an embodiment of the present invention.

Figure 3 illustrates a housing of an electromechanical switch according to an embodiment of the present invention.

Figures 4-7 illustrate a magnet sub assembly of the electromechanical switch according to an embodiment of the present invention.

Figure 8 illustrates the assembly sequence of magnet sub assembly according to an embodiment of the present invention.

Figure 9 illustrates sectional view taken along a plane parallel to and at some distance from rear end wall of the electromechanical switch.

Figures 10 and 11 illustrate actuation of electromechanical switch of the present invention. DETAILED DESCRIPTION OF THE PRESENT INVENTION

While the invention is susceptible to various modifications and alternative forms, specific embodiment thereof has been shown by way of example in the figures and will be described in detail below. It should be understood, however that it is not intended to limit the invention to the particular forms disclosed, but on the contrary, the invention is to cover all modifications, equivalents, and alternative falling with in the spirit and the scope of the invention as defined by the appended claims.

Before describing in detail the various embodiments of the present invention it may be observed that the novelty and inventive step that are in accordance with the present invention resides in the construction of electromechanical switch. It is to be noted that a person skilled in the art can be motivated from the present invention and modify the various constructions of electromechanical switch. However, such modification should be construed within the scope and spirit of the invention.

Accordingly, the drawings are showing only those specific details that are pertinent to understanding the embodiments of the present invention so as not to obscure the disclosure with details that will be readily apparent to those of ordinary skill in the art having benefit of the description herein.

The terms "comprises", "comprising", "including" or any other variations thereof, are intended to cover a non-exclusive inclusion, such that an assembly, mechanism, setup, that comprises a list of components does not include only those components but may include other components not expressly listed or inherent to such assembly, mechanism or setup. In other words, one or more elements in turn indicator control switch or assembly proceeded by "comprises" does not, without more constraints, preclude the existence of other elements or additional elements in the assembly or mechanism. The following paragraphs explain present invention and the same may be deduced accordingly. Accordingly, it is an aim of the present invention to address at least one of the problems associated with the prior existing switches.

Accordingly, the present invention provides a electromechanical switch comprising:

a casing comprising a hollow region and adapted to receive a housing; a housing comprising an exterior and an interior, defined by a bottom wall, a top wall, two opposite side walls, a closed end wall and an open end; a resiliently loaded magnet sub-assembly accommodating a magnet disposed in the housing under a force of a spring, being slidably supported on one or more guiding tracks formed in the interior of the housing; the magnet sub assembly comprising a an adapter and a socket accommodating a magnet;

the socket being adapted to be fitted in a corresponding cavity in the adapter;

the adapter, comprising a cavity to receive the socket and a plurality of projections extending laterally towards the opposite side walls and the bottom wall of the housing;

an actuating shaft has a proximal end being disposed in the interior of the housing so as to remain in contact with the magnet sub -assembly; and a distal end operatively coupled with brake pedal so that movement of the brake pedal causes actuation of the actuating shaft thereby allowing movement of the spring loaded magnet sub-assembly in longitudinal direction;

a PCB assembly accommodated in the housing; the PCB assembly comprises one or more Hall sensors adapted to detect change in magnetic flux due to movement of the magnet sub-assembly and to provide signal indicative of activation of brake light, cruise control etc.

In an embodiment of the present invention the magnet is accommodated in a slot formed in the socket wherein the slot for receiving the magnet may be partially open from upper side when in mounted condition for saving material and reducing cost of component.

In yet another embodiment of the present invention the magnet is accommodated in a slot formed in the socket wherein the slot for receiving the magnet may be covered from upper side when in mounted condition by an upper covering portion for preventing entry of contaminants like dust, water and humidity, thereby enhancing life of component.

In another embodiment of the present invention the socket is provided with a projection adapted to be received in a corresponding cutout formed on the adapter, for ensuring correct orientation of the socket on the adapter.

In still another embodiment of the present invention the magnet sub assembly is disposed in the housing under a force of a spring.

In yet another embodiment of the present invention the spring is accommodated in a cylindrical hole formed in the adapter and the said spring is located on a locating pin formed in the housing.

In a further embodiment of the present invention the magnet is a rectangular magnet.

In a further more embodiment of the present invention the slot is provided with one or more crushing rib for snugly accommodating the magnet therein.

In another embodiment of the present invention the cavity of the adapter is provided with mating ribs to firmly constrain the socket in the cavity in the mounted condition. In still another embodiment of the present invention a first guide track is formed on the side walls of the housing, extending longitudinally between the open end and the closed end wall of the housing; and a second guide track formed on the bottom wall of the housing, extending longitudinally between the open end and the closed end wall of the housing;

In one more embodiment of the present invention the magnet sub assembly is slidably supported on the first and second guide tracks by means of a plurality of projections extending laterally towards the opposite side walls and the bottom wall of the said housing.

The following description describes the present invention with reference to Figures 1 to 10 according to an embodiment of the present invention.

Figures 1 and 2 illustrate an electromechanical switch assembly (1) according to an embodiment of the present invention. Referring to Figures 1 and 2, the electromechanical switch assembly (1) of the present invention comprises a casing (2) and a housing (3) forming an encapsulation for accommodating various components of the switch assembly such as a shaft (4), a magnet sub assembly (5), a spring (6), a PCB sub assembly (7).

As shown in figure 2, the casing (2) has box shaped geometry, formed by side walls (8), an open end (9) and a rear end wall (10). One or more locking grooves (11) are provided on the side walls (8) for securing the casing (2) to the housing (3) for forming an encapsulation (1). The rear end wall (10) is incorporated with a hollow cylindrical trough (12) extending perpendicularly and outwardly from the rear end wall (10) of the casing (2). The hollow cylindrical trough (12) is adapted to receive the actuating shaft (4) in the longitudinal direction. The term 'longitudinal direction' herein refers to a direction perpendicular to the plane of the rear end wall (10). The actuating shaft (4) is a rigid structure having a proximal end (13) and a distal end (14) and is adapted to move longitudinally upon actuation of brake pedal (not shown in Figures).

The term 'proximal end' herein refers to an end of the shaft which is nearer to the magnet sub-assembly. The term 'distal end' herein refers to an end of the shaft which is located far from the magnet sub -assembly as compared to the proximal end.

A skilled artisan can envisage the construction of brake pedal and other components which transfers the actuation force from the brake pedal to the distal end (14) of the actuating shaft (4).

The distal end (14) is adapted to pass through the hollow cylindrical trough (12) of the casing (2). The distal end (14) of the actuating shaft (4) emerges from an open end (12a) of the hollow cylindrical trough (12) for contacting the brake pedal. The proximal end (13) of the actuating shaft (4) is disposed in the interior of the housing (3). The proximal end (13) is a rim shaped structure. The rim shaped structure is an extended diameter portion and provided with a first curved surface (13a) and a second flat surface (13b) opposite to the first surface (13a). The second surface (13b) is provided to abut with a stopping face of the rear end wall (10) under actuated condition of the electromechanical switch (as shown in Figure 10). The first curved surface (13a) of the proximal end (13) of the actuating shaft (4) remains in contact with the magnet sub-assembly (5). The magnet sub assembly (5) is resiliently disposed in the housing (3) and adapted to move in a longitudinal direction upon actuation by actuation shaft (4). The PCB sub assembly (7) is accommodated in the housing (3) so as to be located over the magnet sub assembly (5). The PCB sub assembly (7) comprises one or more Hall sensors or Hall element and is configured to detect magnetic flux or change in magnetic flux due to the movement of the magnet sub assembly (5) and to provide signal indicative of activation of brake light and deactivation of cruise control etc. Figure 3 illustrates a housing (3) of an electromechanical switch (1) according to an embodiment of the present invention. The housing (3) can be made of any suitable material preferably a thermoplastic material. Referring to Figure 3, the housing (3) comprises an exterior (3a) and an interior (3b). The interior (3b) of the housing (3) is defined by a hollow region (15) delineated by a bottom wall (16), a top wall (17), two opposite side walls (18, 19), a front open end (20) and a rear closed end wall (21). The housing (3) is provided with plurality of guiding tracks (22, 23) for slidably supporting the magnet sub assembly (5). As shown in Figure 3, a first guide track (22) is formed on the opposite side walls (18, 19) of the housing. The said first guide track (22) extends longitudinally between the open end (20) and the closed end wall (21) in the interior (13b) of the housing (3). A second guide track (23) is formed on the bottom wall (16) of the housing (3) and extends longitudinally between the open end (20) and closed end wall (21) in the interior (13b) of the housing (3).

Referring to Figure 3, the housing (3) is provided with a locating pin (24) extending towards the open end (20) from the rear end wall (21) of the housing (3) for locating the spring (6).

The housing (3) is provided with slots (25) extending longitudinally between the open end (20) and closed end wall (21) are formed on the side walls (18, 19). The slots (25) are sized to accommodate the PCB sub assembly (7). A plurality of apertures (26) is provided on the closed end wall (21) for projecting there through the terminals of the PCB sub assembly (7) for electrical connection. The exterior (3a) of the housing (3) is provided with one or more snaps (27) adapted to cooperate with the locking grooves (11) provided on the casing (2) for securing the housing (3) with the casing (2) to form an encapsulation (1).

Figures 4-7 illustrate a magnet sub assembly (5) of the electromechanical switch (1) according to an embodiment of the present invention. Referring to Figures 4-8, the magnet sub assembly (5) comprises an adapter (28) and a socket (29) accommodating a magnet (30). In an embodiment, the magnet (30) is a rectangular magnet. The socket (29) is a rigid structure having a slot (31) being sized to removably receive a magnet (30). The slot (31) is provided with one or more crushing ribs (32) to snugly hold the magnet (30) in the slot (31).

The adapter (28) is a rigid structure comprising side faces (33, 34), a bottom face (35) and an upper face (36). The upper face (36) is provided with a cavity (37) adapted to receive the socket (29). In an embodiment, mating ribs (38) are formed in the cavity (37) so as to firmly constrain the socket (29) in the cavity (37) in the mounted condition. The socket (29) can be secured with the adapter (28). For this purpose, a plurality of snaps (39) is provided on outer periphery of the socket (29) for facilitating mounting of the socket (29) on the adapter (28). A plurality of side locks (40) may be formed on the periphery of the upper face (36) to receive the corresponding snaps (39) provided on the socket (29).

In an embodiment, a projection (41) is formed on the socket (29) extending laterally outwardly from the socket (29). The term "lateral" herein refers to a direction perpendicular to the longitudinal direction in a plane perpendicular to the plane of the side walls; and a corresponding cutout (42) is formed on the upper face (36) of the adapter (28) for receiving the projection (41) of the socket (29) to ensure correct orientation of socket (29) when mounted on adapter (28).

In yet another embodiment of the present invention, as shown in figures 6 and 7, the slot (31) for receiving the magnet (30) may be covered from upper side when in mounted condition by an upper covering portion (cu). The thickness of the upper covering portion (cu) may vary between 0.4mm and 0.6mm. The upper covering portion (cu) may protect the magnet (30) in the slot (31) from dust, water, humidity and other contaminants when in the mounted condition. Figure 8 depicts the sequence of assembling the magnet sub-assembly wherein the magnet (30) is first inserted in the slot (31) of the socket (29). The socket (29) is then mounted in the cavity (37) on the adapter (28) to form the magnet subassembly.

Referring to figure 8 in a further embodiment, the upper covering portion (cu) may be avoided on the slot (31) for the purpose of saving cost in respect of extra material used in the upper covering portion (cu).

Figure 9 illustrates a sectional view of the electromechanical switch along a plane parallel to and at some distance from rear end wall of the electromechanical

In an embodiment, a plurality of projections (44, 45) is formed on the adapter (28) for slidably supporting the magnet sub assembly (5) on the guiding tracks (22, 23) formed in the housing (3).

The plurality of projections (44, 45) comprises primary projections (44) extending laterally from the side faces of the adapter (28). As shown in Figure 9, the primary projections (44) on the side faces of the adapter (28) laterally extend towards the opposite side walls (18, 19) in the interior of the housing (3) and are received in the first guide tracks (22) so as to slidably support the magnet sub assembly (5) in the longitudinal direction. Referring to figures 8 and 9, one or more secondary/auxiliary projections (45) are formed on the bottom face of the adapter (28) which extends towards the bottom wall (16) in the interior (3b) of the housing (3). The secondary/auxiliary projections (45) being received in the second guide track (23) and provide support to the magnet sub assembly (5) in the lateral direction.

Figures 10 and 11 illustrate actuation of electromechanical switch (1) of the present invention. As depicted in figure 10, the electromechanical switch is in non- actuated condition. In the non-actuated condition, the brake pedal remains in released state i.e. no force is applied on the brake pedal. The brake pedal is operatively coupled with the distal end of the actuating shaft so as to apply a force on the distal end (14) of the shaft (4) when the brake pedal is in released position. In this position, the second flat surface (13b) of the proximal end (13) of the actuation shaft (4) is not in contact with the rear end wall (10) of the casing (2). The first curved surface (13a) of the actuation shaft (4) is in point contact with the magnet sub assembly (5) due to its hemispherical geometry. The spring (6) which is resiliently in contact with the magnet sub assembly (5) is in compressed state in the non-actuated position of the switch (1). When the brake pedal is pressed or an external force is applied on the brake pedal, the force applied on the distal end (14) of the shaft by the brake pedal getting released. This is non-actuated or no switching condition of the switch.

Referring to Figure 11, when the brake pedal is pressed, the force of the brake pedal on the distal end (14) is removed, the spring (6) expands and pushes the magnet sub assembly (5) thereby resulting in a sliding movement of the magnet sub assembly (5) on the guiding tracks (22, 23). Movement of the magnet sub assembly (5) pushes the first curved surface (13a) of the actuation shaft (4) in longitudinal direction. In this position the second flat surface (13b) abuts with the stopping face (10a) of the rear end wall (10) of the casing (2) to restrict further movement of the actuation shaft (4). This is the actuated or switching condition of the said electromechanical switch.

ADVANTAGES OF THE PRESENT INVENTION

1. In the present invention the magnet in the magnet sub assembly is kept protected from dust, water and other contaminations. Thus enhancing work life cycle of the said electromechanical switch. One more advantage of the present invention is that the magnet in the magnet sub assembly is not in direct contact with surrounding temperature conditions protecting the magnet from the adverse effects of humidity on the magnet's mechanical and magnetic properties. Yet another advantage of the present invention is that the magnet can be easily mounted on the magnet sub assembly enhancing the serviceability of the said electromechanical switch.

Furthermore, an advantage of the present invention is the firm of the magnet with the adapter of the magnet sub-assembly.

Claims

We claim:

1. An electromechanical switch comprising: a casing comprising a hollow region and adapted to receive a housing; a housing comprising an exterior and an interior, defined by a bottom wall, a top wall, two opposite side walls, a closed end wall and an open end; a resiliently loaded magnet sub-assembly accommodating a magnet disposed in the housing under a force of a spring, being slidably supported on one or more guiding tracks formed in the interior of the housing; the magnet sub assembly comprising a an adapter and a socket accommodating a magnet;

the socket being adapted to be fitted in a corresponding cavity in the adapter;

a PCB assembly accommodated in the housing; the PCB assembly comprises one or more Hall sensors adapted to detect change in magnetic flux due to movement of the magnet sub -assembly and to provide signal indicative of activation of brake light, cruise control etc.

2. An electromechanical switch as claimed in claim 1 , wherein the magnet is accommodated in a slot formed in the socket.

3. An electromechanical switch as claimed in claims 1 and 2, wherein the slot for receiving the magnet may be partially open from upper side when in mounted condition.

4. An electromechanical switch as claimed in claims 1 and 2, wherein the slot for receiving the magnet may be covered from upper side when in mounted condition by an upper covering portion.

5. An electromechanical switch as claimed in claim 1 , wherein the socket is provided with a projection adapted to be received in a corresponding cutout formed on the adapter, for ensuring correct orientation of the socket on the adapter.

6. An electromechanical switch as claimed in claim 1, wherein the magnet sub assembly is disposed in the housing under a force of a spring.

7. An electromechanical switch as claimed in claims 1 and 4, wherein the spring is accommodated in a cylindrical hole formed in the adapter and the said spring is located on a locating pin formed in the housing.

8. An electromechanical switch as claimed in claim 1, wherein the magnet is a rectangular magnet.

9. An electromechanical switch as claimed in claim 2, wherein the slot is provided with one or more crushing rib for snugly accommodating the magnet therein.

10. An electromechanical switch as claimed in claim 1 , wherein the cavity of the adapter is provided with a mating ribs to firmly constrain the socket in the cavity in the mounted condition.

11. An electromechanical switch as claimed in claim 1, wherein a first guide track is formed on the side walls of the housing, extending longitudinally between the open end and the closed end wall of the housing; and a second guide track formed on the bottom wall of the housing, extending longitudinally between the open end and the closed end wall of the housing;

12. An electromechanical switch as claimed in claim 1, wherein the magnet sub assembly is slidably supported on the first and second guide tracks by means of a plurality of projections extending laterally towards the opposite side walls and the bottom wall of the said housing.