EMI shielding device

Abstract

The invention relates to an EMI gasket for mounting on a wall of a housing of an electrical appliance. The gasket includes a plurality of elements arranged in a row wherein two adjacent elements are interconnected by connection pieces. At least one of the elements includes a clamping section for clamping the device onto the housing and a shielding section to perform the shielding function. According to the invention, at least one element further includes a snapping member which serves as a barb for latching into a recess within the wall of the housing where the gasket is to be installed such that the gasket is locked on the wall thereby preventing unintentional movement of the gasket or even that the gasket is slipping off of the housing.

Claims

1. An EMI shielding device for mounting on a base, including a plurality of elements arranged in a row wherein two adjacent elements are interconnected, at least one element including a clamping section for clamping the device onto the base, characterized in that said at least one element includes a snapping member for latching into a recess of the base and for locking the EMI shielding device on the base.

2. The EMI shielding device according to claim 1, wherein each element has a strip-like shape including two or more bends.

3. The EMI shielding device according to claim 1, wherein at least one element includes a shielding section.

4. The EMI shielding device according to claim 1, wherein each clamping section includes a bend, a first clamping segment on one side of the bend and a second clamping segment on another side of the bend such that the base can be clamped between the two clamping segments.

5. The EMI shielding device according to claim 4, wherein the snapping member is formed by a section of the first clamping segment protruding towards the second clamping segment.

6. The EMI shielding device according to claim 5, wherein the section of the first clamping segment that forms the snapping member is an end section of the first clamping segment.

7. The EMI shielding device according to claim 6, wherein the shielding section, if present, is arranged at an end section of the second clamping segment.

8. The EMI shielding device according to claim 7, wherein the shielding section includes an arcuate section facing away from the snapping member.

9. The EMI shielding device according to claim 8, wherein the arcuate section points back to the bend of the clamping section.

10. The EMI shielding device according to claim 1, wherein all elements are identical in shape and size.

11. The EMI shielding device according to claim 1, wherein the device is made of a metal, preferably of beryllium copper.

12. The EMI shielding device according to claim 1 for mounting on an edge of a wall, particularly on the edge of a hole in the wall of a casing of an electrical appliance.

13. An electrical appliance with a casing including at least one wall, wherein an EMI shielding device according to claim 1 is mounted on an edge of the wall of the casing.

14. The electrical appliance according to claim 13, wherein the edge is formed by a hole in the wall for feeding a cable through the casing.

15. The electrical appliance according to claim 13, wherein the wall includes a recess and wherein the snapping member of said at least one element of the EMI shielding device is latched into the recess.

16. A method for mounting an EMI shielding device according to claim 1 on a base, including clamping the EMI shielding device on the base by slipping the device onto a wall of the base, characterized in that the method further includes locking the EMI shielding device on the base by latching the snapping member of at least one of the elements of the EMI shielding device that has such a snapping member into a recess of the base.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0046] The drawings used to explain the embodiments show:

[0047] FIG. 1 depicts an EMI gasket according to the prior art in a non-mounted state in a side view.

[0048] FIG. 2 shows the EMI gasket shown in FIG. 1 mounted on the edge of a wall.

[0049] FIG. 3 depicts an EMI gasket according to the invention in a perspective view.

[0050] FIG. 4 shows the EMI gasket shown in FIG. 2 in a side view in a non-mounted state.

[0051] FIG. 5 shows the EMI gasket shown in FIG. 2 in a side view mounted on the edge of a wall.

[0052] FIG. 6 shows another EMI gasket according to the invention in a side view.

[0053] FIG. 7 shows a front view of a first alternative embodiment of the EMI gasket shown in FIG. 6.

[0054] FIG. 8 shows a front view of a second alternative embodiment of the EMI gasket shown in FIG. 6.

[0055] FIG. 9 shows another EMI gasket according to the invention in a side view in a non-mounted state.

[0056] FIG. 10 shows the EMI gasket shown in FIG. 9 in a side view mounted on the edge of a wall.

[0057] FIG. 11-15 represents different examples of EMI gaskets according to the invention in a side view.

[0058] FIG. 16 is an electrical appliance including an opening and recesses for mounting an EMI gasket according to the invention.

[0059] FIG. 17 shows the electrical appliance shown in FIG. 16 with EMI gaskets mounted around the opening and latched into the recesses.

[0060] In the figures, the same components are given the same reference symbols.

PREFERRED EMBODIMENTS

[0061] FIG. 1 shows an EMI gasket 1 according to the prior art. The gasket 1 is shown and it is shown in a state where it is not mounted on a base, a wall or the like. The gasket 1 is shown in a side view in a direction parallel to the longitudinal extension of the gasket 1. FIG. 2 shows the same gasket 1 mounted on the edge of a wall 2 such as for example the wall 2 of a housing of an electrically driven device. Also in FIG. 2 the gasket 1 is shown in the same side view as in FIG. 1.

[0062] The gasket 1 includes a shielding part 3 and a clamping part 4. The clamping part 4 comprises a first clamping leg 4.1 and a second clamping leg 4.2 connected by a kink or bend 4.3. The shielding part 3 is connected to the end of the first clamping leg 4.1 opposite the bend 4.3 and includes several further bends and curves in order to best fulfill the required shielding function together with the shielding function of the clamping part 4.

[0063] The gasket 1 is mounted on the wall 2 by slipping it over the edge of the wall 2 such that the wall 2 becomes positioned between the two clamping legs 4.1, 4.2 as shown in FIG. 2. As can be seen by comparing FIGS. 1 and 2, the clamping part 4 is slightly deformed when the gasket 1 is slipped over the edge of the wall 2 such that the clamping legs 4.1, 4.2 are slightly pushed apart to provide enough room for the wall 2. Accordingly, the clamping part 4 is slightly stressed such that the wall 2 is clamped by the clamping legs 4.1, 4.2 and the gasket is mounted on the wall 2.

[0064] However, as can be seen from FIG. 2, the gasket is not locked in place and can be moved in each direction. It may even slide off the wall 2 unintentionally if someone or something snags on it. And although the second clamping leg 4.2 includes and a bended end section 5 which seems to be rather similar to the barb of a gasket according to the invention, it can be seen that this end section 5 may not latch into a recess or opening within the wall 2, if such a recess or opening would be present at all. Rather, the end section 5 is pressed away from the wall 2 when the gasket 1 is slipped over the edge of the wall 2.

[0065] FIG. 3 shows a first embodiment of an EMI gasket 11 according to the invention. In FIG. 4 the gasket 11 is shown in a side view and in FIG. 5 it is shown in the same side view mounted on the edge of a wall 12 that includes a recess 19. In FIG. 5 actually a cross section of the wall 12 is shown in order to more clearly show the principles of the invention.

[0066] The gasket 11 again includes a shielding part 13 and a clamping part 14 with two clamping legs 14.1, 14.2 interconnected by a bend 14.3. As can be seen, the gasket 11 is formed by a series of single elements 17 arranged in a row where two neighboring elements 17 are interconnected by connection pieces 18. In this case, two neighboring elements 17 are interconnected by two connection pieces 18. In FIG. 3, for reasons of convenience the gasket is shown to include only 13 elements whereas usually such a gasket includes clearly more elements.

[0067] In order to form the shielding part 13 of an element, the end section of an element that is connected to the first clamping leg 14.1 in this embodiment generally includes a large arc or bow which first leads away from the clamping part 14 but points back to back to the bend 14.3 of the clamping part 14.

[0068] At the end of the second clamping leg 14.2, each element of the gasket 11 includes a snapping member in the form of a barb 15. When slipping the gasket 11 onto the edge of the wall 12 for mounting it on the wall 12, the barb 15 is slightly pushed down, which in this case means away from the first clamping leg 14.1, such that the clamp formed by the clamping part 14 is slightly loaded thereby clamping the gasket 11 onto the wall 12. When the gasket 11 is further slipped onto the edge of the wall 12, the barb 15 latches into the recess 19 and thereby locks the gasket 11 on the wall 12.

[0069] In this way, the barb of the gasket 11 very much reduces the risk that that gasket is unintentionally moved out of place or even slipped off of the wall 12. It is however still possible to remove the gasket 11 without spending a great effort or without the risk of damaging the gasket 11 or the wall 12.

[0070] As also can be seen in FIG. 5, the clamping of the gasket 11 on the wall 12 is achieved by the first clamping leg 4.1 and the barb 15 itself.

[0071] FIG. 6 shows a second embodiment of an EMI gasket 21 according to the invention in a side view. The gasket 21 is simpler than the gasket 11 of the first embodiment. It also includes a shielding part 23 and a clamping part 24 with two clamping legs 24.1, 24.2. In this case, the first clamping leg 24.1 more or less corresponds to a straight strip and the second clamping leg 24.2 is shorter than the first clamping leg 24.1. Further, the tip of the barb 25 points back to the first clamping leg 24.1 bit it does point away from the bend 24.3 whereas the tip of the barb 15 in the first embodiment points back to the bend 14.3. The shielding part 23 also just includes a straight piece of the element that is connected to the first clamping leg 24.1 via a further bend of the element.

[0072] FIGS. 7 and 8 show front views in the direction of the arrow 6 of different alternatives 21′, 21″ for the particular shape of the elements of the gasket 21. In FIG. 7, the single elements 27′ of the alternative 21′ are rather long and narrow whereas the elements 27″ of the alternative 21″ are much wider compared to their length. Accordingly, in order to provide about the same length of a gasket, the number of elements 27′ needed in the gasket alternative 21′ is much higher than the number of elements 27″ needed in the alternative 21″.

[0073] Another aspect shown in FIGS. 7 and 8 is that the connection pieces 28′ can be short such as shown in the alternative 21′ or the connection pieces 28″ can be made wider and longer as shown in the alternative 21″.

[0074] FIGS. 9 and 10 show a third embodiment of an EMI gasket 31 according to the invention. The gasket 31 is largely identical to the prior art gasket 1 shown in FIG. 1.

[0075] The only difference is the end section of the second clamping leg 4.2 which is formed by a barb 35 instead of the simple end section 5 shown in FIG. 1. Unlike said end section 5, the barb 35 in this third embodiment can and does latch into a recess 39 of a wall 32 when mounted on that wall 32 as shown in FIG. 10. This is possible because the end section of the clamping leg 4.2 is bent towards the first clamping leg 4.1 and it is a bit longer such that it may still latch into the recess 39 although the wall 32 is clamped between the clamping legs 4.1, 4.2. In fact, what enables the latching of the barb 35 into a recess 39 of a wall 32 when mounted thereon, is the length of the tip of the barb 35. As can be seen in FIG. 9, in the non-mounted state, the distance 37 between the clamping leg 4.1 and the tip of the barb 35 is smaller than the distance 38 between the clamping leg 4.1 and that part 36 of the second clamping leg 42 closest to the clamping leg 4.1. And as shown in FIG. 10, the distance 37 is smaller than the distance 38 also when the gasket 31 is clamped onto the wall 32 and the barb 35 locked into the recess 39.

[0076] As also can be seen in FIG. 10, the clamping of the gasket 31 on the wall is not achieved by the first clamping leg 4.1 and the barb 35 but between the first clamping leg 4.1 and the part 36 of the second clamping leg 4.2 closest to the clamping leg 4.1.

[0077] In FIG. 11-15 side views of different examples of EMI gaskets according to the invention are shown.

[0078] FIG. 11 shows a gasket 41 with a clamping part 44 where the barb 45 is connected to one end of the clamping part 44 and the shielding part 43 is connected to the other end of the clamping part 44.

[0079] Another aspect of the gasket 41 is the shape of the shielding part 43 which is formed by an almost closed loop.

[0080] The clamping part 54 of the gasket 51 shown in FIG. 12 and the barb 55 are identical to the clamping part 44 and the barb 45 of the gasket 41. But the shielding part is much smaller.

[0081] The gasket 51′ shown in FIG. 13 is identical to the gasket 51 except for the barb 55′ which in this case has a tip that includes a further bent such that the barb 55′ is not formed by the end of an element but by a sharp bend.

[0082] The main difference of the gasket 61 compared to the other embodiments is the fact, that the shielding part 63 is not connected to the side of the clamping part 64 opposite to the barb 65 but that the shielding part 63 is connected to the barb 65.

[0083] The gasket 71 shown in FIG. 15 largely corresponds to the gasket 61. However, the shielding part 73 is much larger and is even bent around the whole clamping part 74.

[0084] FIG. 16 shows an electrical appliance 90 including a front wall 92. The front wall 92 includes an opening 93 for feeding cables into and/or out of the appliance 90. The wall 92 further includes a plurality of recesses 99.1, 99.2, 99.3, 99.4 of different shapes and sizes.

[0085] FIG. 17 shows the electrical appliance 90 of FIG. 16 but with EMI gaskets 91 mounted on the edges 93.1, 93.2, 93.3, 93.4 of the opening 93 within the front wall 92. The gaskets 91 are for example gaskets as the one shown in FIG. 6. Apart from their length the gaskets 91 are identical. However, to show the flexibility of the invention, the recesses 99.1, 99.2, 99.3, 99.4 are different for each edge 93.1, 93.2, 93.3, 93.4.

[0086] The wall 92 includes two long and wide recesses 99.1 near the first edge 93.1. When mounting a gasket 91 on the edge 93.1, the distance of the recesses 99.1 from the edge 93.1 is chosen such that the barbs of the gasket can latch into the recesses 99.1 before the gasket is fully slipped onto the edge 93.1. So the gasket can be moved in a direction perpendicular to the edge 93.1 while its barb is latched into the recesses 99.1. Further, as the recesses 99.1 do not extend along the whole edge 93.1, not all barbs of the elements of the gasket 91 can latch into one of the recesses 99.1 but at least some of them do latch into one of the recesses 99.1 thereby locking the gasket 91 on the edge 93.1. It may however be that the gasket may slightly move in a direction parallel to the edge 93.1. But those barbs that are latched into one of the recesses 99.1 prevent that the gasket can be moved too much and they particularly prevent that the gasket may slip off the edge 93.1.

[0087] The wall 92 includes one single, but narrow and long recess 99.2 near the second edge 93.2. When mounting a gasket 91 on the edge 93.2, the distance of the recess 99.2 from the edge 93.2 is chosen such that the barbs of the gasket 91 latch into the recess 99.2 before the gasket is fully slipped onto the edge 93.2. But since the recess 99.2 is rather narrow, the gasket may not be moved in a direction perpendicular to the edge 93.2 once the gasket is locked. And again, only the barbs of the inner elements of the gasket 91 can latch into the recess 99.2 but the barbs of the outer elements may not latch into the recess 9.2. However, the length of the recess 99.2 is adapted to the width of the elements such that the barbs of all middle elements just latch into the recess 99.2 and such that no movement of the gasket 91 in a direction parallel to the edge 93.2 is possible.

[0088] The wall 92 further includes four narrow and short recesses 99.3 near the third edge 93.3. When mounting a gasket 91 on the edge 93.3, the distance of the recesses 99.3 from the edge 93.3 is chosen such that the barbs of the gasket latch into the recesses 99.3 only when the gasket is fully or almost fully slipped onto the edge 93.3. So the gasket cannot be moved anymore in a direction perpendicular to the edge 93.3. Further, as the recesses 99.3 do not extend along the whole edge 93.3, not all barbs of the elements of the gasket 91 can latch into one of the recesses 99.3. In this case, the recesses 99.3 are adapted and arranged such that the barbs of just the first, the third, the sixth and the eighth element of the gasket 91 latch into the recesses 99.3. Since the length of the recesses 99.3 corresponds to the widths of the barbs, the gasket is locked and cannot move.

[0089] The wall 92 further includes a number of narrow and short recesses 99.4 near the third edge 93.4 that corresponds to the number of elements with barbs of the gasket 91 to be mounted. When mounting a gasket 91 on the edge 93.4, the distance of the recesses 99.4 from the edge 93.4 is chosen such that the barbs of the gasket exactly latch into the recesses 99.4 only when the gasket is fully or almost fully slipped onto the edge 93.4. So the gasket cannot be moved anymore in a direction perpendicular to the edge 93.4. Further, the barbs of all elements of the gasket 91 can latch into one of the recesses 99.4. And also in this case, the recesses 99.4 are adapted and arranged such that the barbs of just fit into the recesses 99.4 to lock the gasket on the edge 93.4.

[0090] In summary, it is to be noted that the invention enables to create gaskets that may not be accidentally or unintentionally be moved out of place or even slipped off of the device on which they are mounted. Be adapting the number and shape of the elements of a gasket including barbs and/or by adapting the recesses on the device on which the gaskets shall be installed, some movement may be allowed or even helpful but the invention prevents that a gasket accidentally or unintentionally is moved out of place or even slipped off of the device. The invention enables the creation of self-retaining EMI gaskets. Nevertheless, a gasket according to the invention can also be easily removed in necessary for example to enable repair or service work or just for replacing a gasket.