WO2009025405A1

WO2009025405A1 - A fixing implement of shield case for pcb

Info

Publication number: WO2009025405A1
Application number: PCT/KR2007/004087
Authority: WO
Inventors: Nack Hwan Jeong
Original assignee: Pocons Co Ltd
Current assignee: Pocons Co Ltd
Priority date: 2007-08-17
Filing date: 2007-08-24
Publication date: 2009-02-26
Anticipated expiration: 2010-02-17
Also published as: KR20080006504A; JP2010537421A

Abstract

Disclosed is a fixing implement of a shield case for a PCB. The fixing implement comprises a plurality of fixing sections fixed onto the PCB, and a clamping section provided between the fixing sections to clamp the sidewalls of the shield case. The clamping section comprises a base, and a pair of elastic members extending from both sides of the base while facing each other to elastically clamp the sidewalls, so that the sidewalls inserted between the elastic members are fixed between the elastic members. The fixing sections are soldered to the PCB, the base has a spacer protrusion for spacing between bottom ends of the sidewalls and the base, and a curvature portion is provided in at least a part of the peripheral surface of the fixing section in order to increase a soldering area of the fixing section.

Description

A FIXING IMPLEMENT OF SHIELD CASE FOR PCB

Technical Field

[1] The present invention relates to a fixing implement of a shield case for a PCB

(printed circuit board). More particularly, the present invention relates to a fixing implement of a shield case for a PCB, which can facilitate exchange and repair work for electronic parts mounted on the PCB and can easily fix the shield case to the PCB covering the electronic parts to shield EMI (electromagnetic interference). Background Art

[2] In general, electromagnetic waves are useful for wireless communication or radar communication, but may also have a bad influence on the operations of electronic appliances. Such phenomenon is called EMI phenomenon . Such an EMI causes noise of electronic appliances and harmful for the human body.

[3] In order to solve these problems, a predetermined shield case is provided to cover electronic parts, such as semiconductor devices, mounted on a PCB in electronic appliances, thereby shielding EMI generated from the electronic parts such that the EMI does not exert influence upon the operation of the electronic appliance as well as other electronic appliances. Such a shield case generally has a box shape with an opened lower end portion to cover the electronic parts.

[4] Further, a shield case is generally installed on a PCB through fixing implements that clamp the sidewall of the shield case in a state in which the fixing implements are fixed onto the PCB.

[5] FIGS. 1 and 2 are views showing the structure of the conventional fixing implement.

[6] As shown in FIGS. 1 and 2, the fixing implements 1 are installed on a PCB 3 around electronic parts corresponding to sidewalls 2a of a shield case 2. Each fixing implement 1 comprises fixing sections 4 fixed to the PCB 3 and a pair of clamping sections 5 which can clamp the sidewall 2a of the shield case 2 such that the shield case 2 can be detachably coupled to the PCB 3.

[7] The fixing sections 4 are provided to both ends of the fixing implement 1 and between the clamping sections 5. Outer peripheral portions of the fixing sections 4 are soldered to the PCB 3.

[8] Each clamping section 5 comprises a base 5a and a pair of elastic members 5b that extend upward from both sides of the base 5a and face each other such that the sidewall 2a can be inserted between the elastic members 5b.

[9] The elastic members 5b are bent such that the longitudinal center portions of the elastic members 5b are convex toward the sidewall 2a inserted between the elastic members 5b. The clamping section 5 elastically presses and fixes the inner and outer surfaces of the sidewall 2a by using the elastic members 5b as the sidewall 2a is inserted between the elastic members 5b.

[10] Accordingly, when fixing the shield case 2 to the PCB 3 by using the fixing implements 1 having the structure as described above, the fixing implements 1 are coupled to the PCB 3 corresponding to the sidewalls 2a of the shield case 2 by soldering the fixing sections 4. In such a state, if the sidewalls 2a of the shield case 2 are inserted between the elastic members 5b forming the clamping section 5 of each fixing implement 1, the sidewalls 2a of the shield case 2 are clamped by the clamping section 5 of each fixing implement 1, so that the shield case 2 is simply fixed on the PCB 3.

[11] Further, in this state, if the user pulls up the shield case 2 to replace the electronic parts covered by the shield case 2, the sidewalls 2a of the shield case 2 are easily released from the clamping section 5 of each fixing implement 1. As a result, the shield case 2 can be easily separated. Disclosure of Invention Technical Problem

[12] However, the fixing implements 1 of the shield case for the PCB according to the prior art have the following problems.

[13] First, the fixing implements 1 may be fixed to the PCB 3 in a twisted state such that the sidewalls 2a of the shield case 2 do not match with a space between the elastic members 5b of the clamping section 5. In this case, when the sidewalls 2a of the shield case 2 are clamped by the clamping section 5, the clamping section 5 is twisted and thus the fixed sections 4 integrally formed with the clamping section 5 may be detached from the PCB 3. In order to prevent the problems, the area of the fixed sections 4 is preferably enlarged to increase the bonding force between the PCB 3 and the fixed sections 4. However, the area of the fixing implements 1 on the PCB 3 is excessively increased, and thus a space for installing electronic parts is decreased. Further, the space of the PCB 3 may not be efficiently used.

[14] In addition, in the case of the conventional fixing implement 1, the lower portions of the sidewalls 2a of the shield case 2 make contact with the base 5a of the clamping section 5. When the fixing structure of the shield case is applied to electronic appliances, which generate vibration during operation thereof, such as air conditioners or refrigerators, the lower portions of the sidewalls 2a of the shield case 2 frequently make collision with the base 5a of the fixing implement 1 due to the impact derived from the operation of the electronic appliances, so collision noises may excessively occur. Technical Solution

[15] An embodiment of the present invention provides a fixing implement of a shield case for a PCB, which can be firmly fixed onto the PCB without deteriorating the degree of space efficiency of the PCB.

[16] An embodiment of the present invention provides a fixing implement of a shield case for a PCB, which can effectively reduce contact noise with the shield case.

Advantageous Effects

[17] According to the fixing implement of a shield case for a PCB of the present invention, since the soldering area between fixing sections and a PCB is increased without substantially increasing the area of the fixing sections, the coupling force of the fixing implement relative to the PCB cane be increased without deteriorating the degree of space efficiency of the PCB.

[18] Further, according to the fixing implement of a shield case for a PCB of the present invention, since the sidewalls of the shield case are spaced apart from bases through spacer protrusions, which are provided in the bases of clamping sections, by the height of the spacer protrusions, collision noise between the shield case and the fixing implement can be efficiently suppressed at the starting of electronic appliances even if the fixing implement is applied to the electronic appliances. Brief Description of the Drawings

[19] FIG. 1 is a perspective view showing the structure of a fixing implement of a shield case for a PCB according to the prior art;

[20] FIG. 2 is a sectional view showing a state in which a sidewall of a shield case is cl amped by a clamping section of a fixing implement of the shield case for a PCB according to the prior art;

[21] FIG. 3 is a perspective view showing a PCB, at which a fixing implement of a shield case is installed, and the shield case separated from the PCB according to one preferred embodiment of the present invention;

[22] FIG. 4 is a perspective view showing the structure of a fixing implement of a shield case for a PCB according to one preferred embodiment of the present invention;

[23] FIG. 5 is a plan view showing the structure of a fixing implement of a shield case for a PCB according to one preferred embodiment of the present invention;

[24] FIG. 6 is a sectional view showing a state before a sidewall of a shield case is inserted into a clamping section of a fixing implement of the shield case for a PCB according to one preferred embodiment of the present invention;

[25] FIG. 7 is a sectional view showing a state in which a sidewall of a shield case is being inserted into a clamping section of a fixing implement of the shield case for a PCB according to one preferred embodiment of the present invention; and [26] FIG. 8 is a sectional view showing a state in which a sidewall of a shield case has been completely inserted into a clamping section of a fixing implement of the shield case for a PCB according to one preferred embodiment of the present invention. Best Mode for Carrying Out the Invention

[27] According to a fixing implement of a shield case for a PCB of the present invention, the shield case covers electronic parts fixed to the PCB in order to shield EMI (electromagnetic interference) generated from the electronic parts mounted on the PCB, and the fixing implement comprises: a plurality of fixing sections fixed onto the PCB; and a clamping section provided between the fixing sections to clamp the sidewalls of the shield case, wherein the clamping section comprises: a base; and a pair of elastic members extending from both sides of the base while facing each other to elastically clamp the sidewalls, so that the sidewalls inserted between the elastic members are fixed between the elastic members, wherein the fixing sections are soldered to the PCB, the base has a spacer protrusion for spacing between bottom ends of the sidewalls and the base, and a curvature portion is provided in at least a part of the peripheral surface of the fixing section in order to increase a soldering area of the fixing section.

[28] The spacer protrusion has a height of 0.03mm to0.05mm.

[29] Further, one spacer protrusion is provided in a central portion of the base.

[30] The spacer protrusion is formed by bulking a part of the base upward.

[31] The elastic members comprise first and second clamping sections to elastically clamp inner and outer surfaces of the sidewalls, and, when the first clamping sections are outwardly biased, the second clamping sections are inwardly biased to press the sidewalls, or vise versa.

[32] The first clamping sections are formed by bending the elastic members such that the elastic members protrude inward in the clamping section, the second clamping sections are formed by cutting the elastic members and are bent such that fixing ends thereof are fixed to the first clamping sections and free ends thereof are located inside the clamping section, and an interval between the second clamping sections is smaller than an interval between the first clamping sections.

[33] The second clamping sections are provided to clamp lower portions of the sidewalls.

[34] Further, the second clamping sections are downwardly inclined formed from the fixing ends to the free ends.

[35] The curvature portion has a concave shape in the fixing section to increase length of a peripheral surface of the fixing section without increasing an area in which the fixing section makes contact with the PCB.

[36] Further, two clamping sections are provided in such a manner that the clamping sections are spaced apart from each other in a longitudinal direction of the fixing implement, three fixing sections are provided at both ends of the fixing implement in the longitudinal direction and provided between the clamping sections, and the curvature portion is provided in the fixing sections located at the both ends of the fixing implement in the longitudinal direction. Mode for the Invention

[37] Hereinafter, a preferred embodiment of the present invention will be described with reference to accompanying drawings.

[38] FIGS. 3 and 4 are views showing a state, in which a shield case is separated from a

PCB, and the structure of a fixing implement, respectively, according to an embodiment of the present invention.

[39] As shown in FIGS. 3 and 4, electronic parts 40 such as semiconductor devices are mounted on one side of the PCB 30, and the shield case 20 for covering the electronic parts 40 to shield EMI of the electronic parts 40 is installed at an outer side of the electronic parts 40.

[40] Such a shield case 20 is detachably coupled to the PCB 30 through the fixing implements 10.

[41] The shield case 20 has a rectangular parallelepiped shape in which four sidewalls 21 are integrally formed with a top wall 22, and a bottom section thereof is opened to receive the electronic parts 40 therein. Such a shield case 20 may comprise a tin-plated steel plate for effectively blocking electromagnetic waves.

[42] Further, the fixing implements 10 are coupled to the PCB 30 around the electronic parts 40 so that the fixing implements 10 clamp the sidewalls 21 of the shield case 20 and fix the shield case 20 to be detachable from the PCB 30. Such fixing implements 10 are installed on the PCB 30 around the electronic parts 40 corresponding to the sidewalls 21 of the shield case 20. Stepped grooves 21a are formed at the lower ends of the central portions of the sidewalls 21, which are substantially clamped by the fixing implements 10, so that gaps are not formed between the PCB 30 and the lower ends of the sidewalls 21 at both sides of the stepped grooves 21a in a state in which the sidewalls 21 have been clamped by the fixing implements 10.

[43] Each fixing implement 10 comprises fixing sections 51 and 52 fixed to the PCB 30 and a pair of clamping sections 60 that can clamp the sidewall 21 of the shield case 20 such that the shield case 20 can be detachably coupled to the PCB 30.

[44] Referring to FIGS. 4 and 6, the clamping sections 60 are spaced apart from each other along the longitudinal direction of the fixing implement 10. In detail, two fixing sections 51 are provided at both ends of the fixing implement 10 and one fixing section 52 is provided between the clamping sections 60. The peripheral surfaces of the fixing sections 51 and 52 are soldered to the PCB 30, so that the fixing implement 10 is fixed onto the PCB 30.

[45] Such a fixing implement 10 is shifted into the PCB 30 in a state in which the fixing implement 10 is fixed to a nozzle (not shown) of SMT equipment by a vacuum, and then mounted on the PCB 30. Thus, the fixing section 52 of the fixing sections 51 and 52 forms a suction surface relative to the nozzle (not shown). Accordingly, in a state in which the fixing section 52 has been fixed to the nozzle (not shown) by the vacuum, both sides of the fixing section 52 preferably have shapes symmetrical to each other and the same weight such that the fixing implement 10 cannot be inclined.

[46] Further, each clamping section 60 comprises a base 70 forming a bottom and a pair of elastic members 80 and 90. The elastic members 80 and 90 extend upward from both ends of the base 70 and face each other such that the sidewall 21 can be inserted therebetween.

[47] The base 70 is spaced apart from the upper surface of the PCB 30 by a predetermined interval between the fixing sections 51 and 52 such that the base 70 can function as a buffer. When the shield case 20 is clamped by the clamping section 60, the base 70 prevents the impact from being applied to the PCB 30. A reference numeral 61 is a connection section, which is inclined to connect the base 70 to the fixing section 51 and to connect the base 70 to the fixing section 52.

[48] Accordingly, in order to fix the shield case 20 onto the PCB 30 by using the fixing implements 10, the fixing implements 10 are primarily coupled to the PCB 30 corresponding to the sidewalls 21 of the shield case 20 by soldering the fixing sections 51 and 52 to the PCB 30. In such a state, if the sidewalls 21 of the shield case 20 are inserted between the elastic members 80 and 90 forming the clamping section 60, the sidewalls 21 are clamped by the clamping section 60 of each fixing implement 10, so that the shield case 20 can be simply fixed onto the PCB 30.

[49] In this state, if the user pulls up the shield case 20 to replace the electronic parts 40 covered by the shield case 20, the sidewalls 21 of the shield case 20 are easily released from the clamping section 60 of each fixing implement 10. Consequently, the shield case 20 can be easily separated.

[50] In the fixing implement 10 according to the present embodiment, at least one of the three fixing sections 51 and 52 serves to increase the soldering area of the fixing section 51 or 52 soldered to the PCB 30, and has a curvature portion 53 at the peripheral surface thereof.

[51] Such a curvature portion 53 has a concave shape to increase the length of the peripheral surface without increasing an area in which the fixing sections 51 and 52 make contact with the PCB 30.Accordingly, the fixing implement 10 according to the present embodiment can be firmly fixed onto the PCB 30 without deteriorating the degree of space efficiency of the PCB 30.

[52] That is, the fixing implement 10 may be fixed onto the PCB 30 in a slightly twisted state such that the sidewalls 21 of the shield case 20 do not match with a space between the elastic members 80 and 90 of the clamping section 60. In such a case, when the sidewalls 21 of the shield case 20 are clamped by the clamping section 60, the clamping section 60 may be twisted and thus the fixing sections 51 and 52 integrally formed with the clamping section 60 may be separated from the PCB 30. However, according to the present embodiment, the length of the peripheral surface of the fixing section 51 or 52 soldered to the PCB 30 is increased through the curvature portion 53, so the soldering area of the fixing section 51 or 52 soldered to the PCB 30 is increased and the fixing implement 10 is firmly fixed onto the PCB 30. Thus, even if the clamping section 60 is slightly twisted because the shield case 20 is fixed to the fixing implement 10 in a state in which the sidewalls 21 of the shield case 20 are slightly twisted relative to the elastic members 80 and 90 of the clamping section 60, the fixing implement 10 can be stably fixed onto the PCB 30. Further, since an area occupied by the fixing section 51 or 52 on the PCB 30 is not substantially increased, the degree of space efficiency of the PCB 30 is not degraded due to the fixing implement 10.

[53] Further, the curvature portion 53 may also be formed at all of the three fixing sections 51 and 52. However, when too many curvature portions 53 are formed, the fixing implement 10 may not be easily manufactured. Accordingly, the curvature portion 53 is preferably formed only at the two fixing sections 51 arranged at both ends of the fixing implement 10. According to the present embodiment, the fixing sections 51 and 52 have a rectangular shape, respectively. The curvature portion 53 is formed only at distal end portions of the fixing sections 51 provided at both ends of the fixing implement 10 in the longitudinal direction.

[54] In the fixing implement 10 according to the present embodiment, in order to reduce collision noise between the shield case 20 and the fixing implement 10 when the electronic appliances operate, a spacer protrusion 71 is formed at the base 70 of the clamping section 60 to separate between the base 70 and the lower ends of the sidewalls 21 of the shield case 20 by a predetermined interval.

[55] In more detail, in the case of electronic appliances, in which vibration occurs at the starting of the electronic appliances, such as refrigerators or air conditioners employing the structure in which the shield case 20 is fixed to the fixing implement 10, the sidewalls 21 of the shield case 20 may frequently make collision with the base 70 of the clamping section 60 due to such vibration when the electronic appliances operate. In a case in which the lower ends of the sidewalls 21 make contact with the base 70, collision noise between the base 70 and the sidewalls 21 may excessively occur. [56] However, in the state in which the spacer protrusion 71 is provided at the base 70 as described above, even if the sidewalls 21 move downward while the shield case 20 is being swung due to such vibration occurring at the starting of the electronic appliances, the sidewalls 21 are spaced apart from the base 70 through the spacer protrusion 71 and thus the lower ends of the sidewalls 21 collide only with the spacer protrusion 71. Accordingly, the collision noise between the sidewalls 21 and the base 70 can be efficiently reduced.

[57] If such a spacer protrusion 71 has an excessive height, the sidewalls 21 may not be easily inserted between the elastic members 80 and 90. Thus, the spacer protrusion 71 preferably has a minimum height within the range of spacing between the sidewalls 21 and the base 70. In the present embodiment, the spacer protrusion 71 has a height of 0.03mm to 0.05mm.

[58] Further, the spacer protrusion 71 can be integrally formed with the base 70 by simply applying pressure to the bottom of the base 70 such that the part of the base 70 can protrude upward. In addition, one spacer protrusion 71 is formed at the central portion of the base 70 such that the spacer protrusion 71 can exactly support the lower ends of the sidewalls 21.

[59] In a case in which the sidewalls 21 are strongly clamped between the elastic members 80 and 90 of the clamping section 60, collision between the sidewalls 21 and the spacer protrusion 71 can be suppressed. To this end, in the present embodiment, the elastic members 80 and 90 have a structure capable of strongly clamping the sidewalls 21.

[60] In more detail, the elastic members 80 and 90 have first clamping sections 81 and 91, respectively, formed by bending the central portions of the elastic members 80 and 90 in the longitudinal direction thereof such that the first clamping sections 81 and 91 protrude toward the sidewalls 21 inserted therebetween.

[61] Accordingly, the clamping section 60 elastically presses and fixes the inner and outer surfaces of the sidewalls 21, which are inserted into the clamping section 60, through the first clamping sections 81 and 91.

[62] The interval between the elastic members 80 and 90 at the upper portions of the first clamping sections 81 and 91 is larger than the thickness of the sidewalls 21 such that the sidewalls 21 can be easily inserted into the clamping section 60, and then the interval between the elastic members 80 and 90 is gradually reduced in the downward direction.

[63] Further, second clamping sections 82 and 92 are formed at the central portions of the elastic members 80 and 90 in the longitudinal direction of the fixing implement 10 through a cutting process such that the second clamping sections 82 and 92 can press and fix the sidewalls 21 together with the first clamping sections 81 and 91. [64] The second clamping sections 82 and 92 are formed by cutting predetermined central portions of the elastic members 80 and 90 such that fixing ends 82a and 92a thereof can be fixed to the first clamping sections 81 and 91. After forming the second clamping sections 82 and 92 through the cutting process, the second clamping sections 82 and 92 are bent inward such that free ends 82b and 92b thereof are located inside the clamping section 60. Such second clamping sections 82 and 92 are downwardly inclined from the fixing ends 82a and 92a, which are fixed to the first clamping sections 81 and 91, to the free ends 82b and 92b such that the interval between the free ends 82b and 92b is smaller than the interval between the first clamping sections 81 and 91.

[65] As shown in FIG. 7, in a state in which the sidewalls 21 are inserted into the first clamping sections 81 and 91, the interval between the first clamping sections 81 and 91 is increased in the direction designated by arrow A and the free ends 82b and 92b of the second clamping sections 82 and 92 make contact with each other in the direction designated by arrow B. As the sidewalls 21 are continuously inserted into the second clamping sections 82 and 92, the sidewalls 21 are strongly clamped by the second clamping sections 82 and 92as shown in FIG. 8. Accordingly, the collision between the spacer protrusion 71 and the sidewalls 21 can be efficiently suppressed.

[66] Further, in the case in which the clamping section 60 clamps and fixes the sidewalls

21 through the first clamping sections 81 and 91 and the second clamping sections 82 and 92 as described above, even if the fixing implement 10 does not clamp the sidewalls 21 because the interval between the first clamping sections 81 and 91 becomes larger than the thickness of the sidewalls 21, the interval between the free ends 82b and 92b of the second clamping sections 82 and 92 maintains a narrow state. Accordingly, the second clamping sections 82 and 92 can continuously clamp the sidewalls 21.

Claims

[1] A fixing implement of a shield case for a PCB, in which the shield case covers electronic parts fixed to the PCB in order to shield EMI (electromagnetic interference) generated from the electronic parts mounted on the PCB, the fixing implement comprising: a plurality of fixing sections fixed onto the PCB; and a clamping section provided between the fixing sections to clamp the sidewalls of the shield case, wherein the clamping section comprises: a base; and a pair of elastic members extending from both sides of the base while facing each other to elastically clamp the sidewalls, so that the sidewalls inserted between the elastic members are fixed between the elastic members, wherein the fixing sections are soldered to the PCB, the base has a spacer protrusion for spacing between bottom ends of the sidewalls and the base, and a curvature portion is provided in at least a part of the peripheral surface of the fixing section in order to increase a soldering area of the fixing section.

[2] The fixing implement as claimed in claim 1, wherein the spacer protrusion has a height of 0.03mm to0.05mm.

[3] The fixing implement as claimed in claim 1, wherein one spacer protrusion is provided in a central portion of the base.

[4] The fixing implement as claimed in claim 1, wherein the spacer protrusion is formed by bulking a part of the base upward.

[5] The fixing implement as claimed in claim 1, wherein the elastic members comprise first and second clamping sections to elastically clamp inner and outer surfaces of the sidewalls, and, when the first clamping sections are outwardly biased, the second clamping sections are inwardly biased to press the sidewalls, or vise versa.

[6] The fixing implement as claimed in claim 5, wherein the first clamping sections are formed by bending the elastic members such that the elastic members protrude inward in the clamping section, the second clamping sections are formed by cutting the elastic members and are bent such that fixing ends thereof are fixed to the first clamping sections and free ends thereof are located inside the clamping section, and an interval between the second clamping sections is smaller than an interval between the first clamping sections.

[7] The fixing implement as claimed in claim 6, wherein the second clamping sections are provided to clamp lower portions of the sidewalls.

[8] The fixing implement as claimed in claim 6, wherein the second clamping sections are downwardly inclined formed from the fixing ends to the free ends.

[9] The fixing implement as claimed in claim 1, wherein the curvature portion has a concave shape in the fixing section to increase length of a peripheral surface of the fixing section without increasing an area in which the fixing section makes contact with the PCB.

[10] The fixing implement as claimed in claim 9, wherein two clamping sections are provided in such a manner that the clamping sections are spaced apart from each other in a longitudinal direction of the fixing implement, three fixing sections are provided at both ends of the fixing implement in the longitudinal direction and provided between the clamping sections, and the curvature portion is provided in the fixing sections located at the both ends of the fixing implement in the longitudinal direction.