Comprising Such Spring Assembly

The invention relates to a spring assembly for biasing an armature of a switching device, such as a relay, and a switching device, such as an electromagnetic switching device, like a relay. A switching device, such as an electromagnetic relay, is a basic component of household appliances and is used in power plants and power grids as a switch or a protective device. Such electromagnetic devices comprise an electromagnet, a yoke or core, a movable armature which opens/closes the switch based upon a magnetic field produced by the electromagnet, and a spring assembly for biasing the armature. In a rest or initial position, no electric field is generated by the electromagnet, and the spring assembly biases the armature into either the closed or the open position of the switching device. When the electromagnet is energized and a magnetic field is produced, the armature is moved against the biasing force of the spring assembly into the activated position. The activated position is an open position in case of a closed switch in the initial position, and vice versa. To satisfy market demands, the development of electromagnetic switching devices, such as relays, is trending towards miniaturization, high reliability and so on. The spring assembly for such switching devices often requires a high manufacturing complexity and assembly of the switching device is laborious, leading to complex structures and low manufacturing and assembly efficiency.

Thus, it is the objective of the present invention to provide a spring assembly for biasing the armature of a switching device that has a simple construction and can easily, yet reliably, be mounted in the switching device.

According to the invention, the above problem is solved by a spring assembly for biasing an armature of a switching device, such as a relay, the spring assembly comprising a spring base and at least one spring arm that protrudes from the spring base for biasing the armature, wherein the spring base comprises at least one embossment for positioning the spring assembly in the switching device.

A switching device according to the invention comprises a spring assembly of the invention.

An embossment is a projecting elevation or bulge, such as a curved projection, raising out of the spring base. This is easy to manufacture and allows to simply mount and position the spring assembly with the switching device by pushing it into a corresponding receptacle. In the receptacle, the embossment positions the spring assembly in the switching device. The construction and manufacturing can surprisingly be simplified and be made more efficient by the present invention due to the embossment, i.e. a shape projecting above the surface of the spring base providing a press-fitting element.

The inventive solution can be improved through the following embodiments, which are advantageous on their own and can be combined arbitrarily as desired. In one embodiment, the at least one embossment is configured for press-fittingly positioning the spring assembly in the switching device. Here, the embossment provides a press-fit that positions and fixes the spring assembly in the switching device. No additional fixation means such as screws or rivets are necessary, thus minimizing the number of components needed and facilitating the mounting of the spring assembly. Further, due to the press-fitting provided by the embossment, no constructive restrictions with respect to mounting the spring assembly arise.

In one embodiment, the at least one embossment forms a protuberant pad which allows for evenly distributing the pressing forces for positioning over a desired surface area. Such a protuberant pad, e.g. in the design of a cushion bulging out of the spring base surface, results in a simple and compact construction and can be easily manufactured in a manner allowing to push-in the spring assembly for mounting and press-fittingly position it in the switching device.

The height of the embossment, i.e. the measure by which the embossment projects out of the base, can be greater than the thickness of the base material measured in the direction in which the embossment protrudes from the base. This provides a pressing force sufficient to fixingly position the spring assembly in the switching device. In a further embodiment, the spring base may comprise at least two embossments which advantageously provides the pressing forces at distinct positions of the spring base. The at least two embossments can be arranged spaced apart from each other, in particular spaced apart from each other in a direction perpendicular to an insertion direction in which the spring base is mounted in the switching device. Such a construction enhances stability by more evenly distributing the press-fitting positioning force over the area of the spring base.

For locking the spring assembly in its mounted position in the switching device, the spring base may comprise a base securing element. The base securing element avoids an unintentional demounting or removal of the spring assembly.

The base securing element may be a latching element that can be brought into engagement with a holding surface of the switching device. The latching element can, for example, be a notch, slot or recess to be connected with a corresponding counter element, such as a hook or nose. The latching element can be a deflectable projection. Such a resilient catch can be easily produced and allows for an efficient locking of the spring assembly in the switching device. Upon pushing the spring assembly into its position, the latching element is deflected. When the spring assembly reaches its final mounting position in the switching device, the latching element may spring back into its initial position, abutting against a holding surface in the switching device, thus securely locking the spring assembly against removal.

In one embodiment, a latching hook or arm may be provided on the spring base. The latching hook may be preferably provided at the edge of the spring base that faces in the insertion direction, i.e. the part of the spring base that points in the insertion direction and is thus first inserted upon mounting the spring assembly. Such a latching hook can easily be produced by bending back a hook section of the spring base, said hook section being the foremost part of the spring base facing in the insertion direction.

A very slim and compact design of a switching device can be achieved in an embodiment according to which the spring base is angular, comprising as a first leg a positioning area with the at least one embossment, and as a second leg a spring support area holding a proximal end of the at least one spring arm.

In a further embodiment, the spring base may comprise a spring rate adjustment section. The spring rate adjustment section defines the biasing force provided by the spring assembly biasing and acting on the armature in the switching device. This way, a single design of a spring base can be used, providing different spring rates customized for the switching device in which the spring assembly is used by merely adapting the spring rate adjustment section, while keeping the rest of the assembly the same. In the spring rate adjustment section, material may be removed from the spring base, thus lessening the spring rate of the assembly. In one embodiment that has an easy and compact construction, the spring base is provided with a cut-out, resulting in a through-hole. The form, area and positioning of the cut-out may efficiently adjust the spring rate of the spring assembly. The spring rate adjustment section may be arranged at the angle/elbow at which the first and second leg of the angular embodiment of the spring base meet.

In a further embodiment, the spring assembly comprises at least two spring arms. This design is particularly suited for a relay having an O-shaped armature, allowing to bias each of two arms of the armature. The distal ends of the at least two spring arms may point away from the same side of the spring base, in particular matching the design of an O-shaped armature.

A very compact design may be achieved in an embodiment, wherein two spring arms extend, at least in sections, oblique to each other. Such an oblique extension results in a V-shape, in which the spring arms do not extend parallel to each other. This design reduces the material required, compared to e.g. U-shaped designs. Further, the size of the spring base and/or the lengths of the spring arms can be reduced in an embodiment where two spring arms each comprise proximal orientation sections, one end of which orientation section is connected with the spring base, and which proximal orientation sections protrude away from the spring base oblique to each other. The proximal orientation section may extend up to the distal end of each spring arm. In another embodiment, a spring arm may, in addition to the proximal orientation section, comprise a distal section, wherein the distal sections of two spring arms run parallel to each other.

The assembly of the switching device can be facilitated and made efficient in an embodiment in which the at least one, preferably each, spring arm comprises an attachment element for connecting the spring arm with the armature. The attachment element may be arranged in a distal section or at the distal end of the spring arm, thus providing good leverage and force transmission for biasing the armature.

The attachment element may be connected with the armature using a material bond, such as welding or an adhesive joint. To facilitate such a material bond, the distal end of the at least one spring arm may be provided with an attachment section. Said attachment section may comprise a hole, through which the spring arm can be fixed on the armature by e.g. laser welding.

In another embodiment which allows for an easy assembly and reassembly of the spring assembly, the attachment element may be designed to engage the spring arm with the armature in a form fit. In such an embodiment, the attachment element may be a positive-locking element, such as a hook or nut. In one embodiment, the positive-locking element may be a deflectable latching element, such as a clip or clamp that may be brought into engagement with a part of the armature. A secure connection can be achieved in case the form-fitting positive-locking element surrounds the armature at at least two, preferably three, sides, with respect to the cross-section area of the armature. This also facilitates the biasing of the armature by the spring assembly. In another embodiment, which is compact and can be easily mounted without the need to significantly change the design of the armature, the attachment element is arranged on a lateral edge of the spring arm. Such a lateral arrangement, i.e. providing the attachment elements sideways, allows to provide the connection between the spring arm and the armature collaterally at an arbitrary position of the armature, e.g. an O-shaped armature. In order to make the manufacturing process simple, the spring assembly can be monolithically formed. It can be made from sheet material, having its elements, for example, be cut from sheet metal and be bent and punched to achieve the desired shape. In the switching device according to the present invention, comprising the spring assembly of the invention, the spring assembly can preferably be positioned press-fittingly in a spring base receptacle. The yoke may provide a limit for the spring base receptacle, so that the spring base may be engaged in a press-fit with the yoke. A positioning wall may provide an alternative or additional limit for the spring base receptacle. The positioning wall can be a continuous wall over the whole width of the spring base or the whole spring assembly. Alternatively, the positioning wall can be provided merely opposite the embossments.

In an embodiment of the spring assembly comprising a base securing element, said base securing element may be brought into engagement with the yoke as well, providing a very compact design. In the following, the inventive solution will be explained in more detail with reference to the drawings. The features shown in the advantageous embodiments can be combined arbitrarily as desired, and are advantageous on their own.

In the Figures:

Fig. 1 shows a perspective view of a first embodiment of the spring assembly; Fig. 2 shows a top view of the first embodiment of the spring assembly of Fig. 1 ;

Fig. 3 shows a rear view of the spring assembly of the first embodiment of Fig. 1, also schematically outlining its attachment with the armature of the switching device;

Fig. 4 shows a side view of the spring assembly of the first embodiment of Fig. 1 , also outlining the attachment of the armature and the positioning and locking of the spring assembly at the yoke of the switching device; and

Fig. 5 shows a schematic top view of a switching device according to the present invention, comprising the spring assembly of the first embodiment, as shown in Figs. 1 to 4.

In Figs. 1 to 4, an embodiment of a spring assembly 1 is shown. The spring assembly 1 is for biasing an armature 2 of a switching device 3, e.g. an electromagnetic switching device, like a relay 4. Such a switching device 3 comprises, in addition to the spring assembly 1 and the armature 2, an electromagnet 5 and a yoke or core 6 for attracting the armature 2, if the electromagnet 6 produces an electric field, against a biasing force BF provided by the spring assembly 1.

The spring assembly 1 comprises a spring base 7, and at least one spring arm 8 that protrudes from the spring base 7 for biasing the armature 2 into an initial or rest position. In said rest position, the at least one spring arm 8 moves the armature 2 away from the yoke 6 in the direction of the biasing force BF.

The spring base 7 comprises at least one embossment 9 for positioning the spring assembly 1 in the switching device 3. The at least one embossment 9 in the shown embodiment, is configured for press-fittingly positioning the spring assembly 1 in the switching device 3.

The spring assembly 1 is mounted in the switching device 3 by pushing it in an insertion direction ID into a mounting receptacle 10. In the shown embodiment, the mounting receptacle 10 is limited on one side by the yoke 6 and on the opposite side by the positioning wall 11 of the switching device 3. The insertion direction ID is opposite the direction of the biasing force BF. Thus, the spring assembly can be easily positioned in the switching device 3 by pushing its spring base 7 in the insertion direction ID into the mounting receptacle 10, in which it is positioned press-fittingly due to the at least one embossment 9 provided on the spring base 7. The positioning wall 11 can be a continuous wall over the whole width of the spring base 7 or the whole spring assembly 1. Alternatively, the positioning wall 11 can be provided merely opposite the embossments 9. To press-fittingly position the spring assembly 1, the width of the mounting receptacle WMR is smaller than the thickness of the spring base 7, including the height HE of the embossment 9, i.e. the measure by which the embossment 9 stands out from the spring base 7. If the height HE of the embossment 9 is equal to or slightly smaller than the width WMR of the mounting receptacle 10, the spring assembly may be positioned, however, not press-fittingly fixed. Upon pushing the spring base 7 into the mounting receptacle 10 in the insertion direction ID, the embossment 9 is compressed and, due to the compression, press-fittingly positions the spring assembly 1 in the switching device 3.

In the shown embodiment, the at least one embossment 9 forms a protuberant pad 12 that is designed as a cushion, bulging out of the spring base 7. In the shown embodiment, the spring base 7 comprises two embossments 9. The two embossments 9 are spaced apart from each other in a direction perpendicular to the insertion direction ID, in which the spring base 7 is mounted in the switching device 3. The two embossments 9 are arranged at opposite ends of the spring base 7.

The spring base 7 further comprises a base securing element 13 for locking the spring assembly 1 against removal in its mounting position in the mounting receptacle 10 of the switching device

3. In the shown embodiment, the base securing element 13 is a latching element 14, that is designed as a latching hook or finger 15, formed by a folded back hook section 16 of the spring base 7. The hook section 16 is provided at a distal edge 17 of the spring base 7 facing in the insertion direction ID. The hook section 16 is folded or bent back against the insertion direction ID, thus forming a deflectable hook or finger, comprising a stopping face 18 on the free end of the latching hook 15. The stopping face 18 points against the insertion direction ID. When mounting the spring assembly 1 in the switching device 3 by pushing its spring base 7 in the insertion direction ID into the mounting receptacle 10, the latching hook 15 is deflected and pressed against the spring base 7 until it passes the yoke 6 and engages and abuts with its stopping face 18 at the yoke 6. This way, the spring assembly 1 is secured in its mounting position and cannot be removed from the switching device 3 against the insertion direction ID, due to being locked at the yoke 6 (see e.g. Fig. 4).

In the shown embodiment, the spring base 7 is angular, comprising as a first leg 19 a positioning area 20, and as a second leg 21 a spring support area 22. The first leg 19 and second leg 20 are connected by an elbow 23. The positioning area 20 comprises the two embossments 9, as well as the base securing element 13, designed as a latching hook 15. At the spring support area 22, the proximal end 24 of the spring arm 8 is held. Such an angular spring base 7 provides a compact design, in which the spring arms 8 may be arranged in the area perpendicular to the insertion direction ID. The elbow 23 provides a spring characteristic allowing the second leg 21 to be deflected relative to the form-fittingly positioned first leg 19 that is locked in the mounting receptacle 10. In the shown embodiment, the spring base 7 further comprises a spring rate adjustment section 25. In the spring rate adjustment section 25, material is removed from the spring base 7. For removal, the material may be cut off in the spring base, producing a through-hole 26 that is arranged at the elbow 23. In the shown embodiment, material is removed from the elbow 23 and both the first leg 19 and the second leg 21 of the spring base 7. The form, design and position of the spring rate adjustment section 25 allows to provide a desired spring rate/biasing force BF that is optimized for the respective switching device 3.

In the shown embodiment, the armature 2 is O-shaped, designed as a frame, laterally surrounding, if viewed in the insertion direction ID, the electromagnet 5. The exemplary embodiment of the spring assembly 1 shown in the Figs comprises two spring arms 8 that both point away from the same side of the spring base 7. Such a design is particularly suited to bias parallel legs of an O-shaped armature 2. The two spring arms 8 each comprise a proximal orientation section 27, whose proximal end 24 is connected with the spring support area 22 of the spring base 7. The proximal orientation section 27 of the two spring arms 8 protrude away from the spring base 7, oblique to each other. That is, the two spring arms 8 extend, at least in sections, oblique to each other, designed in a V-shape.

Each spring arm 8 also comprises a distal attachment section 28, at which the spring arm 8 is connected with the armature 2 in a manner biasing the armature 2 in the direction of the biasing force BF in a very compact, yet efficient design. This can be seen in particular in Fig. 5. The distal attachment section 28 runs parallel, in the shown embodiment, and flush with parallel legs of the O-shaped armature in the insertion direction 10.

For connecting the spring arm 8 with the armature 2, the spring arm 8 comprises an attachment element 29. In the shown embodiment, the attachment element 29 is a positive-locking element 30, that is form-fitting ly connected with the armature 2. To do so, the positive-locking element 30 comprises a spring latching element 31 that is designed as a clip or clamp 32. The spring latching element 31 surrounds the armature 2 at at least two sides, namely at the side facing in the insertion direction ID, i.e. direction against the biasing force BF, and a lateral side, perpendicular to the biasing force BF.

The spring latching element 31 , in the shown embodiment, is arranged at a lateral edge 33 of the spring arm 8. It could likewise be arranged at the distal end 34 of the spring arm 8. This way, the spring arm 8 engages the armature 3 from three sides, as can be seen in Fig. 3, the sides facing in and against the biasing force BF/insertion direction ID, and one lateral side thereof. Connecting such an attachment element 29 with the armature 2 can simply be achieved by providing a clip 32 designed as a deflectable latching hook protruding from the spring arm 8 against the biasing direction BF. Pressing the clip 32 against the biasing force BF along the armature 2 brings it into engagement therewith.

In an alternative embodiment, which is not shown, the attachment element 29 may be designed as a flat attachment pad on the distal end 34. Such a pad may be provided with a hole, through which the spring arm 8 can be fixed on the armature, e.g. by laser welding or other ways of material bonding. Using a fastening means, such as a screw or rivet, is also possible.

In the shown embodiment, the spring assembly 1 of the present invention is monolithically formed. This can keep the manufacturing process of the spring assembly 1 simple. The spring assembly 1 can be made from sheet metal, that is cut out from a sheet of metal and subsequently bent and punched to achieve the desired shape, such as the shape of the exemplary embodiment shown in Figs. 1 to 5. REFERENCE NUMERALS

1 spring assembly

2 armature

3 switching device

4 relay

5 electromagnet

6 yoke/core

7 spring base

8 spring arm

9 embossment

10 mounting receptacle

11 positioning wall

12 protuberant pad

13 base securing element

14 latching element

15 latching hook/finger

16 hook section

17 distal edge

18 stopping face

19 first leg

20 positioning area

21 second leg

22 spring support area

23 elbow

24 proximal end of spring arm

25 spring rate adjustment section

26 through-hole

27 proximal orientation section

28 distal attachment section

29 attachment element

30 positive-locking element

31 spring latching element

32 clip/clamp

33 lateral edge

34 distal end of spring arm BF biasing force ID insertion direction HE height of embossment

WMR width of mounting receptacle