VIBRATION ISOLATORS FOR PRINTED WIRING BOARDS
A vibration isolator device for printed wiring boards. An example vibration isolator device includes a solder tab with an elastomeric material that is adhesively attached to a first side of the solder tab. The second side of the solder tab is attached to a printed wiring board. Solder paste is pre-applied to the printed wiring board prior to attachment of the vibration isolator device. The solder tab has a U-shaped cross section.
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Present vibration acoustic isolators for printed wiring boards (PWB) are typically too large to fit on small PWB's used with micro-electro mechanical systems (MEMS) gyros. Typical devices that are used for isolating PWB's from undesired shocks are used between a package that includes the PWB's and the device to which the package is mounted. This method is costly because of the number of steps for installation. Also, these isolators are large with respect to small printed wiring boards, thus occupying valuable space.
SUMMARY OF THE INVENTIONThe present invention provides a vibration isolator device for printed wiring boards. An example vibration isolator device includes a solder tab with an elastomeric material that is adhesively attached to a first side of the solder tab. The second side of the solder tab is attached to a printed wiring board.
In one aspect of the present invention, solder paste is pre-applied to the printed wiring board prior to attachment of the vibration isolator device.
In another aspect of the present invention, the solder tab has a U-shaped cross section.
In still another aspect of the present invention, a receiving groove is located on a side of a printed wiring board. The groove receives at least a portion of the elastomeric material.
In yet another aspect of the present invention, the tab is a solderable material. The solder tab and elastomeric material are extracted from a linear extension of a plurality of solder tabs with attached elastomeric material.
The system 20 includes one or more isolators 26 that attach to the PWB 24 and provide isolation between the PWB 24 and the base and walls 22 of the package. The isolator 26 includes a solder tab 30 and an elastic isolator 28. The isolators 26 may be formed in an elongated form supplied in a flexible reel. An operator cuts a portion of the isolator 26 from the reel for use prior to attachment to the PWB 24. In one embodiment, the solder tab 30 is brass or is a metal or other alloy having similar properties to brass for solderability. The elastic isolator 28 is a silicone based isolator or is a material having similar properties such as rubber cement. The elastic isolator 28 is adhesively attached to one side or a portion of one side of the solder tab 30. The elastic isolator 28 is attached using an adhesive or is directly attached to the solder tab 30 because it has adhesive properties.
The solder tab 30 is sized based on the thickness of the PWB 24 before it is attached to the PWB 24. The solder tab 44 is preformed into a cross sectional U-shape that is sized to be received by the PWB 24. Before the isolator 26 is attached to the PWB 24, a mask is applied to the PWB 24 based on the location where the solder tab 30 will come in contact with the PWB 24. Then, a solder paste, for example, lead Pb, tinSn, an oil-based resin or comparable adhesive material, is applied to the PWB 24 based on the applied mask. Then, the mask is removed after the application of the solder paste and the isolator 26 is placed onto the desired location on the PWB 24 either manually or by a pick and place automated machine (not shown). If the solder paste requires heat curing, then after the isolator 26 is attached to the PWB 24 and possibly after any electronic components are attached to the PWB 24, a heating process (e.g. IR reflow, wave process, or other known techniques) is applied to all, thereby simultaneously curing the electronic components and the isolators 26 to the PWB 24.
In one embodiment, the solder tab 30 of the isolator 26 is cut from the flat tape reel with a thickness greater than the thickness of the PWB 24. When the isolator 26 is to be attached to the PWB 24, a manual or automatic device bends the solder tab 30 around the edges of the PWB 24 in order to form a cross-sectional U-shape.
As shown in
In the present invention, the isolators can be moved on the board in relation to the board's center of gravity. This adjustability allows “tuning” of the board to eliminate vibration resonance nodes and improve on isolation performance parameters such as VRE (vibration rectification error).
While the preferred embodiment of the invention has been illustrated and described, as noted above, many changes can be made without departing from the spirit and scope of the invention. For example, the isolator described above may be for providing vibration isolation for a variety of support structures other than printed wiring boards. Accordingly, the scope of the invention is not limited by the disclosure of the preferred embodiment. Instead, the invention should be determined entirely by reference to the claims that follow.
Claims
1. An isolator apparatus comprising:
- a solder tab; and
- an elastomeric material adhesively attached to a first side of the solder tab,
- wherein a second side of the solder tab is attached to a support structure.
2. The apparatus of claim 1, further comprising a solder material positioned between the solder tab and the support structure.
3. The apparatus of claim 1, wherein the solder tab has a U-shaped cross section.
4. The apparatus of claim 1, wherein the solder tab is a solderable material.
5. The apparatus of claim 1, wherein the solder tab and elastomeric material are extracted from a linear extension of a plurality of solder tabs with attached elastomeric material.
6. The apparatus of claim 5, wherein the linear extension of a plurality of solder tabs with attached elastomeric material is provided on a reel.
7. The apparatus of claim 5, wherein the solder tabs are placed in desired positions on the support structure using an automated pick and place machine.
8. The apparatus of claim 1, wherein the support structure is a printed wiring board.
9. An isolator system comprising:
- one or more isolator devices comprising: a solder tab; and an elastomeric material adhesively attached to a first side of the solder tab;
- a support structure; and
- a package,
- wherein a second side of each solder tab is attached to a support structure and the support structure is mounted within the package such that only the elastomeric material makes contact with the package.
10. The apparatus of claim 9, wherein the support structure is a printed wiring board.
11. The system of claim 10, wherein the printed wiring board comprises a receiving groove located on one side, the groove configured to receive at least a portion of the elastomeric material.
12. The system of claim 10, wherein the one or more isolator devices are positioned on at least one of an edge or side of the printed wiring board based on center of gravity of the printed wiring board.
Type: Application
Filed: Aug 21, 2007
Publication Date: Feb 26, 2009
Applicant: HONEYWELL INTERNATIONAL INC. (Morristown, NJ)
Inventors: William P. Platt (Forest Lake, MN), Larren E. Boyd (Golden Valley, MN), James P. Turner (St. Paul, MN), Lori J. Armon (Minneapolis, MN)
Application Number: 11/842,456
International Classification: B65D 85/00 (20060101);