Adhesive bonding and miscellaneous chemical manufacture – Methods – Surface bonding and/or assembly therefor
Reexamination Certificate
1999-11-12
2003-05-13
Sells, James (Department: 1734)
Adhesive bonding and miscellaneous chemical manufacture
Methods
Surface bonding and/or assembly therefor
C156S073200, C156S073600
Reexamination Certificate
active
06562164
ABSTRACT:
The invention was not made by an agency of the United States Government nor under contract with an agency of the United States Government.
FIELD OF THE INVENTION
This invention relates generally to devices and methods used in the precision assembly of component parts, and specifically to devices and methods for terminating optical cables by connecting optical fibers to optical connectors.
BACKGROUND OF THE INVENTION
Numerous manufacturing processes involving the assembly of component parts require that a first component part be accurately placed within or inserted into a second component. Often these components are extremely small or fragile, and assembly requires devices and methods which are specifically designed to accommodate such components. Satisfactory assembly of these components also depends upon accurate alignment of the components relative to one another such that a precise fit between certain parts is achieved. Furthermore, accurate alignment of a first component and a second component which is to receive and form a union with the first component is also necessary to prevent jamming, fracturing, or breaking of one or both of the components. However, such precise alignment is often difficult and prohibitively expensive to attain because additional steps must be added to existing processes, or special devices must be designed and implemented to achieve acceptable results. Therefore, there is a need for devices and methods that promote precise alignment between components which can be quickly and inexpensively incorporated into existing manufacturing systems. The use of vibratory or wave energy to increase the accuracy and efficiency of existing systems achieves such a result.
Vibratory or wave energy at varying frequencies, amplitudes and power densities can be utilized at different phases of the manufacturing process. Firstly, vibratory or wave energy can be used for mixing two or more adhesive compounds without generating unwanted heat which may cause an adhesive mixture to cure prematurely. Furthermore, a mixing process utilizing vibratory or wave energy can effectively degas the mixed components if the mixed components are liquids. Secondly, vibratory or wave energy facilitates the flow of certain viscous liquids, such as adhesives, into small spaces where wetting of all surfaces is desired, and complete filling of the small space, without voids or gaps is necessary. Thirdly, vibratory or wave energy may be used to promote joining or alignment of close tolerance parts, particularly when these parts are small in size and fragile in nature. The application of vibratory or wave energy tends to naturally center a first part relative to a second part, when the first part must be inserted through an opening in the second part. This effect results from the tendency for a component, part, or other object to seek its lowest energy state. This tendency is a critical element in automating the assembly of fiber optic components, and may be equally useful in the assembly of close tolerance machinery, various electronic components, and other items of manufacture. Fourthly, vibratory or wave energy can be used to heat materials, and may be utilized in heat bonding or heat curing certain materials. Adhesives which normally take minutes or even hours to cure, can be heat-cured in just seconds with the application of vibratory or wave energy. Thus, vibratory or wave energy curing processes can greatly reduce the time required to assemble certain parts.
There are a variety of known uses for vibratory and wave energy in industrial processes. U.S. Pat. No. 4,176,909 to Prunier discloses a process for fixing a connector to a fiber optic cable by ultrasonically welding a connector made of a thermoplastic material to an optical cable while exerting radial compressive force on the assembly. U.S. Pat. No. 4,265,689 to Jeffrey discloses a method of joining glass objects utilizing ultrasonics. U.S. Pat. No. 4,339,247 to Faulkner et al. discloses a method of separating a dissolved gas from a liquid by means of an acoustic transducer. U.S. Pat. No. 4,548,771 to Senapati et al. provides a method for vulcanizing rubber by mean of applying ultrasonic energy. U.S. Pat. No. 4,867,817 to Kneafsey et al. provides a method for activating microencapsulated chemical compositions by sonication. U.S. Pat. No. 5,300,162 to Brockmeyer et al. discloses a process for producing an optical coupler by ultrasonically welding polymeric optical fibers to a plastic tube; and U.S. Pat. No. 5,690,766 to Zwick discloses a method of bonding an integrated circuit chip to a lead frame which includes the step of applying vibrations from an acoustic source to temporarily change adhesive rheology during the manufacturing process. However, the prior art does not address the use of vibratory energy to facilitate precision assembly of components or parts in an industrial process such as the assembly of fiber optic connectors.
Fiber optic technology plays a crucial role in modern communications. However, for fiber optic cables to be useful, optical fibers must be precisely aligned so that the signal from one cable passes to another cable with minimal loss of the signal. The fiber optics industry has developed a number of standard connectors that can be affixed to the ends of optical fibers for precisely positioning the ends of two optical fibers relative to one another. Attaching an optical connector to the end of a fiber optic cable is referred to as a termination. These terminations are produced in large quantities, and due to the extremely close tolerances between the fiber and the connector required for high transmission rates at the connection between fibers, such terminations must conform to exacting requirements to function properly. Optic fiber terminations are typically assembled by trained laborers who perform most or all of the steps manually. The assembly process requires much skill, and due to frequent technician error, the quality of terminations produced is not consistent. Therefore, devices and methods are needed which can effectively automate the assembly process thereby consistently producing high quality optical fiber terminations.
There are four primary aspects to the process for assembling fiber optic terminations: (a) preparing the adhesive or epoxy which is injected into the optical connector, (b) injecting the correct volume of adhesive into the optical connector, (c) accurately inserting the optical fiber into the optical connector, and (d) curing the adhesive within the optical connector following insertion of the optical fiber into the connector. Preparation and curing of the adhesive can be accomplished by utilizing vibratory or wave energy, as previously described. However, additional methods and devices are needed to accomplish the adhesive injection and fiber insertion steps.
As previously stated, the adhesive injection step is currently accomplished manually through the efforts of a skilled technician. Despite skill and training, these efforts still require guesswork, and can produce unacceptable numbers of nonfunctional terminations. Thus, there is a need for an automated adhesive injection system that consistently dispenses the correct amount of adhesive into an optical connector. Several methods are known regarding injection of adhesive into optical connectors. U.S. Pat. No. 5,815,619 to Bloom discloses a fiber optic connector which is hermetically terminated. U.S. Pat. No. 5,858,161 to Nakajima et al. provides a method for assembling a fiber optic connector which includes the use of a specially designed jig for injecting epoxy into a connector, and U.S. Pat. No. 5,913,001 to Nakajima et al. discloses a similar epoxy injection device. However, these methods and devices do not address the issue of automation of the injection process so to minimize technician inconsistency and error.
As with the adhesive injection step, insertion of an optical fiber into an optical connector is also accomplished manually. This manual process is time-consuming and the results are inconsistent and unpredictable;
Agans Thomas Richard
Ensminger Dale
Faulkner Lynn LeRoy
Fredette Lee
Mogren Malcolm Campbell
Battelle (Memorial Institute)
Miller Courtney J.
Richards William B.
Sells James
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