WO2012123811A2

WO2012123811A2 - Emi/esd shield clip

Info

Publication number: WO2012123811A2
Application number: PCT/IB2012/000512
Authority: WO
Inventors: Motomu Kajiura; Takahisa Ishishita; Yasutoshi KADEMA
Original assignee: Fci; Fci Connectors Singapore Pte Ltd
Priority date: 2011-03-11
Filing date: 2012-02-28
Publication date: 2012-09-20
Also published as: WO2012123811A3

Abstract

The present invention provides a clip for mounting an EMI/ESD shield onto a circuit board. The clip has a first mounting member and a second mounting member arranged in a base plane for fixing to the circuit board and a first and second beams linking the first and second mounting members. The first and the second beams define a gap therebetween for receiving a portion of the shield. Each beam has an inner edge adjacent to the gap. The first beam includes a first tab projecting from the inner edge of the first beam into the gap. The first tab is deflectable to allow insertion of the portion of the shield into the gap and upon insertion of the portion of the shield into the gap, the first tab urges against the portion of the shield to prevent detachment of the shield from the circuit board.

Description

EMI/ESD Shield Clip

Field of the Invention

The present invention relates to a structure for mounting components to a circuit board and in particular, to a clip for mounting a shield cover to a circuit board. The present invention also relates to an assembly utilizing such clips. Background of the Invention

In electronic devices such as a mobile phone, some electronic components are sensitive to electromagnetic interferences (EMI) or electrostatic charges (ESD) and need to be protected in order to be properly functioning. To provide such protection, a metal shield is used to cover such sensitive components mounted onto a printed circuit board (PCB). Conventionally, such a metal shield is fixed to the PCB, e.g. by soldering.

Soldering process is time-consuming and with high cost. Removal of the metal shield must involve de-soldering process which is even less efficient to handle. It is therefore desirable to provide a device and system to allow easy mounting and removal of a cover or shield onto / from a circuit board without involving soldering / de- soldering process.

Summary of the Invention

In one embodiment according to the present invention, a clip is provided for mounting an EMI / ESD shield onto a circuit board. The clip has a first and a second mounting members arranged in a base plane for fixing to the circuit board and a first and second beams linking the first and second mounting members. The beams define a gap therebetween for receiving a portion of the shield. Each beam has an inner edge adjacent to the gap. The first beam includes a first tab projecting from the inner edge of the first beam into the gap. The first tab is resilient and defiectable to allow insertion of the portion of the shield into the gap and upon insertion of the portion of the shield into the gap, the first tab urges against the portion of the shield to prevent detachment of the shield from the circuit board.

For a better understanding of the present invention and its purpose and preferred embodiments, further description accompanied by figures is provided in detail below.

Brief description of the drawings

Fig. 1 is a perspective view of a shield assembly utilizing clips according to an embodiment of the present invention.

Fig. 2 is an exploded view of Fig. 1.

Fig. 3 is a partial enlarged view of Fig. 2.

Fig. 4 is a schematic perspective view showing a clip of Fig. 1.

Fig. 5 is a top view of Fig. 4.

Fig. 6 is a front view of Fig. 4.

Fig. 7 is a partial enlarged view of Fig. 1.

Fig. 8 is a cross-sectional view of Fig. 7 along A- A.

Fig. 9 is a cross-sectional view of Fig. 7 along B-B. Detailed Description of Preferred Embodiments

As shown in Figs 1, 2 and 3, on a printed circuit board (PCB) 20 there are mounted electronic components 22 which are sensitive to electromagnetic signal and / or electrostatic discharge and need to be protected. A metal shield 10 serves the purpose of protection which, can be mounted to PCB 20 and encloses electronic components 22 therein. To mount shield 10 to PCB 20, one or more clips 100 are provided, each having mounting members attached to PCB 20, and a clamping structure to hold shield 10.

Detailed structure and operation of clip 100 are illustrated below, in conjunction with Figs. 3 to 9.

As shown in Fig. 3 to 6, a clip 100 according to one embodiment of the present invention may be made from a single piece of metal sheet material, by stamping for instance. Clip 100 has a first mounting member 110 and a second mounting member 120 arranged in a base plane 102. First and second mounting members 110 and 120 may both be in the form of a pad suitable to be attached to PCB 20 by, e.g. surface mount technology (SMT) process. Although not shown in the figures, it should be appreciated that mounting members may alternatively be of a different form, e.g. soldering tails which may be mounted to the PCB by inserting into the through holes provided on the PCB. A first beam 130 and a second beam 140 are formed integrally with and connecting first and second mounting members 110 and 120. First and second beams 130 are separated from each other to form a gap 150 therebetween. Gap 150 is parallel to longitudinal direction 104 of clip 100.

First beam 130 has a first inner edge 132 adjacent to gap 150. First inner edge 132 may be of a stepped shape to form a pair of first shoulder portions 136 and a first recess 138 between first shoulder portions 136. Likewise, second beam 140 has a second inner edge 142 adjacent to gap 150. Second inner edge 142 may be stepped to form a pair of second shoulder portions 146 and a second recess 148 between second shoulder portions A first tab 134 is formed on first beam 130, and extends from first inner edge 132 into gap 150 towards second beam 140. A second tab 144 is formed on second beam 140, and extends from second inner edge 142 into gap 150 towards first beam 130. First and second tabs 134, 144 are positioned offset from the center of respective recesses 138, 148, and are arranged in a staggered manner along longitudinal direction 104 of clip 100. First tab 134 faces second recess 148, and second tab 144 faces first recess 138. In an embodiment shown in Fig. 5, first and second tabs 134, 144 extend beyond center line 106 of gap 150. In this way, first and second tabs 134, 144 both occupy more than half of the width of gap 150. One advantage of arranging first and second tabs 134, 144 in a staggered manner is that, in a process of fabricating clip 100 by stamping a metal sheet, the portion of the metal sheet at the location corresponding to second recess 148 provides materials to form the front portion of first tab 134, and the portion of the metal sheet at the location corresponding to first recess 138 provides materials to form the front portion of second tab 144. In applications where the mounting space available on a PCB for the clips is very limited, the clips is made in very tiny dimension, e.g. with an overall footprint of about 4.3mm length (L) by 1.5mm width (W) (Fig. 3). Utilizing sheet materials at the locations of the recesses to form part of the tabs allows the tabs to be formed with sufficient length and resiliency to provide the desired clamping effect. Arranging first and second tabs 134, 144 in a staggered manner allows first and second tabs 134, 144 to be formed extending beyond the gap center but without interfering with each other. First and second tabs 134, 144 can therefore possess sufficient resiliency for fixing and removal of the shield to / from the PCB.

In one embodiment, first and second beams 130, 140 are elevated above base plane 102, with first and second head and tail portions 130a, 130b, 140a and 140b of first and second beams 130 and 140 arranged perpendicular to base plane 102. This structure provides a space to accommodate first and second tabs 134, 144 which are bent downward toward base plane 102. In addition, gap 150 may be extended through first and second mounting members 110, 120 such that, gap 150 is formed across the full length of first and second beams 130, 140. In use, as shown in Figs. 3, 7, 8 and 9, one or more clips 100 are firstly mounted to PCB 20, with mounting members 110 and 120 fixed to PCB, by soldering for instance. Side wall 12 of shield 10 is then inserted into gap 150 of clip 100 and is hold to PCB 20 by being clamped by clip 100. First and second tabs 134, 144 are resilient and deformable such that, when side wall 12 of shield 10 is inserted into gap 150, side wall 12 urges against first and second tabs 134 and 144 and force first and second tabs 134 and 144 to deflect away from gap 150. Meanwhile, due to the resilient property, first and second tabs 134 and 144 are kept in contact with and apply force onto, side wall 12, hence to clamp shield 100 onto PCB 20 to protect electronic components 22 from electromagnetic interference and electrostatic discharge. With first and second beams 130, 140 bent down towards base plane 102, insertion of shield 100 into gap 150 becomes easier. However, one skilled in the art would appreciate that a clip with tabs not bent towards the base place can still clamp and mount a shield onto a PCB.

When it is desired to get access to components 22, in an inspection, rework or repairing operation for instance, shield 10 may be removed from PCB 20 by being pulled upwardly, i.e. away from PCB 20. When the pulling force is greater than the clamping force provided by clip 100, shield 100 can be detached from PCB 20, hence to uncover electronic components 22. Due to the resilience nature, when shield 10 is detached from PCB 20, first and second tabs 134 and 144 spring back to their original position and resume partial occupation in gap 150. Clip 100 is now in a condition for next time mounting of shield 10. Accordingly, a clip according to the present invention can provide solution to detachably mount a shield onto a PCB. Mounting and removal of the shield becomes easy and efficient, without involvement of any soldering / de-soldering process.

Although embodiments of the present invention have been illustrated in conjunction with the accompanying drawings and described in the foregoing detailed description, it should be appreciated that the invention is not limited to the embodiments disclosed. For example, the clip may have only one tab extending from one of the first and the second beams, and the only one tab extends into the gap and exerts force against the shield when the shield is inserted into the gap. Alternatively, depending on the physical dimensions available on the PCB, each beam may have two or more tabs extending into the gap. Therefore, the present invention should be understood to be capable of numerous rearrangements, modifications, alternatives and substitutions without departing from the spirit of the invention as set forth and recited by the following claims.

Claims

1. A clip for fixing a shield to a board, the clip comprising:

a first and a second mounting members arranged in a base plane for fixing to the board;

a first and a second beams linking to the first and second mounting members, the first and second beams defining a gap therebetween for receiving a portion of the shield, each beam having an inner edge adjacent to the gap; a first tab projecting from the inner edge of the first beam into the gap;

wherein the first tab is deflectable to allow insertion of the portion of the shield into the gap and

upon insertion of the portion of the shield into the gap, the first tab urges

against the portion of the shield to prevent detachment of the shield from the board.

2. The clip of claim 1, wherein the first tab extends beyond a center line of the gap.

3. The clip of claim 1, further comprising a second tab projecting from the inner edge of the second beam into the gap, wherein the second tab is deflectable to allow insertion of the portion of the shield into the gap and urge against the portion of the shield.

4. The clip of claim 3, wherein the first and second tabs are arranged in a staggered manner along a longitudinal direction of the clip.

5. The clip of claim 4, wherein the first beam has a first recess adjacent to the first tab, the second beam has a second recess adjacent to the second tab, the first tab is positioned facing the second recess and the second tab is positioned facing the first recess.

6. The clip of claim 5, wherein the first tab extends beyond a center line of the gap, and the second tab extends beyond the center line of the gap.

7. The clip of claim 4, wherein the inner edges of each of the first and second beams is stepped defining a pair of shoulder portions, a first recess is formed between the shoulder portions of the first beam, a second recess is formed between the shoulder portions of the second beam, and wherein the first tab is projected from the first recess of the first beam, and the second tab is projected from the second recess of the second beam.

8. The clip of claim 3, wherein the first and second beams are elevated from the base plane.

9. The clip of claim 8, wherein the first and second tabs are bent towards the base plane.

10. The clip of claim 9, wherein the first tab extends beyond a center line of the gap, and the second tab extends beyond the center line of the gap.