1. Field of the Invention
The present invention pertains to a method and apparatus for applying gasket strips to a surface. More particularly, the invention relates to an automated system using a robot guided head to manufacture gasket patterns, and is particularly suitable for applying gasket strips to circuit boards, covers, fixtures, cases components, etc.
2. Description of the Related Art
Electronic circuit boards may require some type of shielding to prevent interference from electromagnetic signals. The shielding can protect the circuits on a circuit board from signals generated from sources outside the circuit board, or protect components and circuits outside the circuit board from signals generated on the board itself. It may also be desirable to shield components and circuits on one part of the circuit board from components and circuits on another part of the same circuit board.
Shielding to prevent interference can be provided by applying an Electro-Magnetic Interference (EMI) shielding gasket to the circuit board. The gasket material usually has conductive characteristics to act as an effective shield against electromagnetic signals. Surrounding the component where the interference must be shielded, the gasket is typically compressed between the circuit board and a metal cover or case.
There are presently only a few methods of applying a shielding gasket to a circuit board, cover, or case. The first utilizes a molded gasket of the desired shape which is either glued in place, pressed onto a ridge (like a saddle), pressed onto a groove or channel, or uses the circuit board bolts to keep from shifting during use. Another method uses die-cut gasket patterns, but this is very expensive due to the high material waste. Additionally, both of these methods are extremely labor intensive, costly to redesign, and thus unpopular. They also limit the designer because changes to a design mid-production can be extremely costly.
Another method for shielding circuits is to place beryllium copper clips or pegs onto a cover that makes contact with the circuit board. These, however, are labor intensive, costly to redesign, and difficult to put on. An innovative method of applying gasket material that eliminates these shortcomings is desirable.
Gasket strips are also used in other industries. For example, automotive gaskets are used for sealing various engine parts to maintain gas and liquids, and in areas such as windshields to seal the environment from the car's interior. One device as disclosed in U.S. Pat. No. 4,759,810 to Jackson et al. applies precut lengths of gasket strips to a windshield. Because the gasket material must be precut, and an operator must load precut rolls of gasket in the device, it is not easily adaptable to different gasket patterns. Moreover, the device lays down a one piece continuous length of gasket to form the entire gasket pattern. This is not suitable for making complicated gasket patterns that may require many individual strips.
Accordingly, one object of the present invention is to provide a method and apparatus for applying gaskets that is less labor intensive.
Another object is to provide a method and apparatus for applying gaskets that is less expensive.
A further object of the invention is to provide a method and apparatus for applying gaskets that minimizes the gasket material required.
Another object of the invention is to provide an automated method and apparatus for forming complicated patterns of gasket strips.
Another object is to provide an automated method and apparatus capable of making different patterns of gaskets.
Additional objects, advantages and novel features of the invention will be set forth in part in the description which follows, and in part will become apparent to those skilled in the art upon examination of the following or may be learned by practice of the invention. The objects and advantages of the invention can be realized and attained by the method and apparatuses particularly pointed out in the appended claims.