Abstract:
This invention relates generally to a method and apparatus for electroplating selected portions of a high contact force, high elastic response range pin-receiving and cylindrical electrical contact having a pair of spaced apart cantilever beams which extend forwardly from a base to a pin-receiving end. In accordance with the invention at least one plating cell is provided including a cavity type of enclosure thereof in general matching the outer contour of the lower portion and pin receiving end of the contact whereas plating solution is ejected towards the pin receiving end including at least one conducting device for electric current is provided adjacent to the opposite region of the contact for engaging with thereof whereas electric current is being conducted.

Description:
RELATED APPLICATIONS 
     This application claims the priority date of a prior filed application having Ser. No. 61/209,616 and filing date of Mar. 9, 2009 and entitled: Device to selective plate female and male electrical contacts. 
     INCORPORATION BY REFERENCE 
     Applicant(s) herein incorporate by reference, any and all U.S. patents and U.S. patent applications cited or referred to in this application. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of Invention 
     This invention relates to electroplating and more particular to the localized plating of different areas of a singular part with various metals. 
     2. Description of Related Art 
     The following art describes the present state of this field: 
     Electroplating is a coating process for metals to be applied onto a basis metal surface. The coating or plating process is accomplished by means of an electrolyte solution which enables the to be plated metal to be deposited from either metal chip anodes—same metal as to be plated—or neutral metal anodes for plating from the electrolyte through application of a current. The current is supplied by means of a rectifier or power supply. The current is variable whereby the voltage is low and constant. The positive terminal of the rectifier is connected to the anode and the negative terminal to the to be plated part or cathode. Both the anode and parts or cathode typically are fully submerged in the electrolyte. The electrolyte is water based with dissolved salts thus making the electrolyte conductive sustaining a relative low electrical resistance. Once current is applied to the now closed circuit the metal is being deposited onto the part&#39;s surface. In case of precious metal plating and specifically gold the gold is suspended in form of gold salts in the electrolyte. The current will enable the gold to be carried out of suspension and deposited onto the part. Whichever portion of the part is selected to be submerged in the electrolyte that is the portion, which will be plated with gold. These electrical contacts come in many configurations and sizes. When the contacts are being plated they are connected with a contactor for the application of current for the plating process. As there is a plurality of contacts being plated in one cycle it is essential that all contacts have a proper connection to the power supply via a contactor as such at least one contactor is assigned to one contact. Location and presentation of the contacts is accomplished with a pallet having an array of through holes arranged in an equally spaced array in such a way that the holes are in alignment vertically with locator sleeves in coaxial fashion provided by a locator plate below the pallet. When the holes of the pallet are properly aligned to be coaxial with the locator sleeves below a contact or other long cylindrical object can be inserted with its far end coming to rest on a locator ledge of the sleeve. Once all holes are filled with the components the plating process can commence. Thus the components can now be exposed to the electrolyte liquid for coating same components in a localized and predetermined area of the component. This type of plating process is commonly known as selective plating meaning that gold or other applicable precious metal is being deposited exclusively in strategic areas of the contact. Strategic areas are where the mating of female to male contact takes place for proper electric conductance once assembled in a connecting device. Specifically applicable to female contacts better known as socket contacts the selective plating as present art teaches does not minimize gold consumption. The reason for this is that the mating end of the contact is exposed to the electrolyte whole meaning that not exclusively the inside diameter or mating area is being plated with thick gold but the outer diameter is being plated with an even thicker layer of gold simultaneously. The reason for this is that the outer diameter of the contact is exposed to the electrolyte at a higher degree in terms of volumetric exchange thereof than the inside diameter of the contact thereby resulting in a higher plating efficiency for the outside diameter. Although prior art selective plating remains to be an economically viable process application it does not reduce gold consumption nearly to the degree as is desirable. 
     No prior art device is known to achieve discrete plating of female contacts as a method and apparatus for electroplating selected portions of the female contacts and specifically describing a method wherein aforesaid are plated simultaneously, consistently and accurately wherein all selected portions of the contacts not to be plated or at least to be plated with a minimum thickness remain so consistently not plated or at least plated by resulting in a minimum thickness respectively. 
     SUMMARY OF INVENTION 
     The present invention teaches certain benefits in construction and use, which give rise to the objectives described below. 
     This invention relates generally to a method and apparatus for electroplating selected portions of a high contact force, elastic response range pin-receiving and cylindrical electrical contact having a pair of spaced apart cantilever beams which extend forwardly from a base to a pin-receiving end. In accordance with the invention at least one plating cell is provided including a cavity type of enclosure thereof in general matching the outer contour of the lower portion and pin receiving end of the contact whereas plating solution is ejected towards the pin receiving end including at least one conducting device for electric current is provided adjacent to the opposite region of the contact for engaging with thereof whereas electric current is being conducted. 
     A primary objective of one embodiment of the present invention is to provide an apparatus and method of use of such apparatus that yields advantages not taught by the prior art. 
     A still further objective is to assure that an embodiment of the invention is capable of plating individual contacts thereby applying the plating to discreet areas of the contacts. 
     A still further objective is to assure that an embodiment of the invention is capable of plating the individual contacts simultaneously, complete and at high speed. 
     A still further objective is to assure that an embodiment of the invention is to assure that individual contacts are plated at a uniform thickness of plating. 
     A still further objective is to assure that an embodiment of the invention is that the individual contact can be plated at a higher thickness of the metal in areas where it is needed and not to include areas where it is not needed. 
     A still further objective is to assure that an embodiment of the invention is that preparation of the contacts for the plating process does not require skilled labor and is relatively easy to use. 
     A still further objective is to assure that an embodiment of the invention is that contacts of various dimensions and configurations respectively can be plated without the need for labor-intensive changes between production batches of contacts. Aforesaid shall result in maximization of efficiency, reduction in labor and reduction in capital expenditures for the plating equipment. 
     Other features and advantages of the embodiments of the present invention will become apparent from the following more detailed description, taken in conjunction with the accompanying drawings, which illustrate, by the way of example, the principles of at least one of the possible embodiments of the invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings illustrate at least one of the best mode embodiments of the present invention. In such drawings: 
         FIG. 1  is a front elevation view of a preferred embodiment of present invention showing a process tank with a receiving device having a contact engaged with conducting device. 
         FIG. 2  is a side elevation and partial cross sectional view taken along lines  2 - 2  respectively in  FIG. 1 . 
         FIG. 3  is a cross sectional view with breakaway feature taken along lines  3 - 3  respectively in  FIG. 2 . 
         FIG. 4  is a cross sectional view taken along lines  4 - 4  respectively in  FIG. 3 . 
         FIG. 5  is a cross sectional view taken along lines  5 - 5  respectively in  FIG. 4 . 
         FIG. 6  is a front elevation of a female contact having a cut away cross section view of the mating end. 
         FIG. 7  is a further front elevation of a female contact having a cut away cross section view of the mating end. 
     
    
    
     The above-described drawing figures illustrate the present invention in at least one of its preferred, best mode embodiments, which are further, defined in detail in the following description. Those having ordinary skill in the art may be able to make alterations and modifications in the present invention without departing from its spirit and scope. Therefore it must be understood that the illustrated embodiments have been set forth only for the purposes of example and that they should not be taken as limiting the invention as defined in the following. 
     DETAILED DESCRIPTION OF THE INVENTION 
       FIG. 1  is a front elevation of the present invention. An electrolyte reservoir  2  is straddled by a plurality of support members  30 . A plurality of stand offs  29  elevate the support members  30  which are attached to each other forming a frame  34  positioned above the electrolyte reservoir  2 . A plurality of receiving devices  20  preferably, plating cartridges, carry contacts  11  which are positioned in an upright attitude. A plurality of contactors  40  are fixed to an insulator platen  32  so that they are in coaxial alignment with the contacts  11 . A lower extremity of each contactor  40  is engaged with an upper extremity of one of the contacts  11  via reciprocating action of platen  32  by means of a plurality of compression springs  19  and the further reciprocating action of contactors  40  by means of compression springs  40 A. The upper extremities of the plurality of contactors  40  are connected to a minus pole of a power supply  9  via transmission leads  9 B. A transmission lead  9 A is connected to a plus pole of power supply  9  and is further connected to an anode  8 , as-shown, in  FIG. 2 . 
       FIG. 2  is a cross section in side elevation of the present invention. The electrolyte reservoir  2  is fully purged with electrolyte  14 . An electrolyte recirculation pump  12  comprises an outlet side connected to a compartment  4  by means of an outlet pipe arrangement  13 . The inlet side of the pump  12  is connected by means of an intake pipe arrangement  15 . The compartment  4  is placed internally within reservoir  2  and submerged in electrolyte  14 . Furthermore the compartment  4  is enclosed by means of an upper manifold  6  which supports the receiving devices  20 . Upon activation of pump  12  the electrolyte  14  is exhausted through the intake pipe arrangement  15  in a direction of flow indicated by arrow  12 A and expelled into compartment  4  via the outlet pipe arrangement  13  as indicated by arrow  12 B. The pressurization of the electrolyte  14  below the manifold  6  forces the electrolyte  14  to rise and flow through plating cartridges  20  to be expelled into electrolyte reservoir  2  as is shown in  FIG. 3  and  FIG. 4 . 
     Upon activation of a plating cycle, power supply  9  delivers an electric current via lead  9 A to anode  8 , and further via electrolyte  14  and plating cartridges  20  to contacts  11 , and still further via contactors  40  and solder connections  40 B, and transmission leads  9 B to the common (minus pole) of the power supply  9 , thereby closing the electric circuit. It is note-worthy to mention that the volume of electrolyte dispensed and the dispersion rate determines the length of the plating cycle and the uniformity of thickness of the plating applied over a given surface area. This can be easily controlled with the aid of a control valve, not shown, positioned in line with outlet pipe arrangement  13 . 
       FIG. 3  shows a partial cross section along the vertical plane of the present invention. The plating cartridge  20  comprises a cylindrical body  24  which is supported within through hole  6 A of manifold  6 . A sealing cap  22  is fastened by a plurality of fasteners  21  on the upper extremity of the body  24 . A circular seal  23  is sandwiched between groove  24 J in the upper extremity of the body  24  and the lower extremity of the sealing cap  22 , with the seal  23  mated into a respective groove  22 A. At the paint of engagement of the contactor  40  with the contact  11  contactor  40  urges the lower extremity of the contact  11  against land  25  of cavity  24 D thereby enveloping, in close proximity, the outer contour of the lower portion of the contact  11 . The inner diameter of the circular seal  23  is sized to be in immediate adjacency with the outer diameter of contact  11  thereby forming a hermetic seal. An electrolyte supply channel  24 A informs a through hole configuration along the vertical plane and is axially aligned with cavity  24 D. An electrolyte drain channel  24 B forms a through hole configuration along the horizontal plane and is slightly elevated in vertical distance above the lower extremity of the cavity  24 D and land  25 , and furthermore, as shown in  FIG. 4 , the axis of the drain channel  24 B converges with the axis of the electrolyte supply channel  24 A. As shown in  FIG. 2 , the electrolyte  14  is pressurized by means of pump  12  and therefore flows as indicated by arrow  26 A in  FIG. 3 , via the supply channel  24 A, to flood the lower extremity of contact  11  at a height equal to or slightly higher than the upper extremity of the drain channel  24 B. Specifically contact  11  at the point of adjacency with the circular seal  23  is provided with an airtight seal thereby preventing air from being evacuated from cavity  24 D below the circular seal  23 . This “airlock” prevents electrolyte  14  from rising higher than slightly above the drain channel  24 B prior to being discharged in direction of flow as indicated by arrows  26 C and  26 D.
         It is noteworthy to mention that a plating process is most efficient and uniform for as long as an adequate volume of electrolyte is constantly exposed to the surface to be plated. The critical area for best function of a female contact is that the lower portion of the inside mating area is plated in sufficient thickness with gold. With the described arrangement, a large volume of electrolyte is exposed to the inside diameter of contact  11  whereas the outside diameter thereof is sufficiently masked by the sleeve configuration of cavity  24 D providing a greatly minimized volume of electrolyte exchange on its surface. As such the thickness of gold is of a considerably lesser thickness on the outside diameter of contact  11 , also known as the “non-functional area,” and greatly increased in thickness on the inside diameter respectively thereof, also known as the “functional area.” A further critical requirement is that the vertical distance of the plating measured from the tip of contact  11  should be only slightly greater than a product specification might require. Therefore it is very conceivable that the vertical distance of drain channel  24 B, as measured from the land  25 , determines the height of the plating because as soon as the level of electrolyte  14 , supplied via supply channel  24 A, exceeds the total area of the opening of the drain channel  24 B, entrapped air prevents the level of electrolyte  14  from rising any further forcing it to evacuate via the drain channel  24 B. It is well known in industry that the prior art teaches the submerging of the contact to a given depth into an open reservoir of electrolyte wherein the depth is the vertical distance as measured from the bottom tip of the contact to the surface of the electrolyte at a ratio of 2.5 to 1 for the plating to take effect. This means that to achieve a specified plating thickness at the depth of 1, the contact has to be submerged into the electrolyte at 2.5 times the depth of 1. As a consequence, to achieve this it further means that a sufficient plating thickness at 1 necessitates an area of 1.5 in addition to 1 to be plated at a thickness equal to the thickness at 1. A primary reason for this is that the volumetric exchange of electrolyte is insufficient to produce a specified thickness of the plating at a given depth for any length of plating time unless the contact is sufficiently submerged in depth into the electrolyte. Negating the effect of an airlock as described above in addition to negating a targeted and dynamic volumetric electrolyte exchange enabled by the plating cartridge configuration furthermore negates the ability to limit the plating to areas where it is needed to satisfy a specified plating thickness at a specified area of contact  11 .       
     In preference for achieving optimized plating efficiency and a minimum of gold consumption respectively, a gap separates beams of the female contact  11  and are aligned with drain channels  24 C and  24 B as shown in  FIG. 3  and  FIG. 4  the latter showing a cross section view along line  4 - 4  of  FIG. 3 . Therefore, we have provided a means for sufficient drainage of the electrolyte  14  via drain channel  24 C in the direction of flow as indicated by arrows  26 F and  26 E respectively for maintaining an optimized volumetric exchange of the electrolyte  14  during the plating cycle. The automatic orientation of contact  11  is easily achieved by means of sensor equipment readily available in commerce. 
       FIG. 5  is a cross section along lines  5 - 5  on  FIG. 4  showing drain channels  24 B and  24 C respectively axially intersecting each other and supply channel  24 A. It is contemplated that a shut-off mechanism like a plug type feature may be used for disabling drain channel  24 B and  24 C respectively and can be provided as an optional feature advantageous for process performance under certain conditions such as when a required flow rate of electrolyte  14 , is needed in combination with the configuration of the contact  11 . Furthermore, as shown in  FIG. 4 , the gaps separating the opposing tines of contact  11  are axially aligned with the drain channel  24 B. 
       FIG. 6  shows a cut away cross section view of the mating end of contact  11  after being gold plated as is practiced with prior art. The plating is shown in heavy lines  11 C and  11 D respectively whereby the line thickness denominates the thickness of the plating. The plating  11 D is necessary for proper functioning of contact  11  when it is installed into a connecting device. 
       FIG. 7  shows a cut away cross section view of the mating end of contact  11  after the gold plating thereof performed with the present invention. The plating  11 E represents the functional area whereby the plating  11 F is the nonfunctional area respectively. The plating  11 F is shown in a lesser line thickness in comparison to  11 E for demonstrating the degree of plating thickness. The thickness of lines  11 D and  11 C ( FIG. 6 ) versus the plating thickness of lines  11 E and  11 F ( FIG. 7 ) are of differing thickness. Furthermore as is easily recognizable the plating depth as depicted by the length of lines  11 D and  11 C versus the length of lines  11 E and  11 F are of greatly unequal length. In retrospect prior art selective gold plating for contacts has a significant disadvantage in comparison to the present invention thereby rendering the present invention as a superior plating method in terms of minimizing gold consumption for selective plating of female contacts. 
     The enablements described in detail above are considered novel over the prior art of record and are considered critical to the operation of at least one aspect of one best mode embodiment of the instant invention and to the achievement of the above described objectives. The words used in this specification to describe the instant embodiments are to be understood not only in the sense of their commonly defined meanings, but to include by special definition in this specification: structure, material or acts beyond the scope of the commonly defined meanings. Thus if an element can be understood in the context of this specifications as including more than one meaning, then its use must be understood as being generic to all possible meanings supported by the specifications and by the word or words describing the element. The definitions of the words or elements of the embodiments of the herein described invention and its related embodiments not described are, therefore, in this specifications to include not only the combination of elements which are literally set forth, but all equivalent structure, material or acts for performing substantially the same function in substantially the same way to obtain substantially the same result. In this sense it is therefore contemplated that an equivalent substitution of two or more elements may be made for any one of the elements in the invention and its various embodiments or that a single element may be substituted for two or more elements in a claim. Changes from the claimed subject matter as viewed by a person with ordinary skill in the art, not known or later devised, are expressly contemplated as being equivalents within the scope of the invention and its various embodiments. Therefore, obvious substitutions now or later known to one with ordinary skill in the art defined to be within the scope of the defined elements. The invention and its various embodiments are thus to be understood to include what is specifically illustrated and described above, what is conceptually equivalent, what can obviously substituted, and also what essentially incorporates the essential idea of the invention. While the invention has been described with reference to at least one preferred embodiment, it is to be clearly understood by those skilled in the art that the invention is not limited thereto. Rather, the scope of the invention is to be interpreted only in conjunction with the appended claims and it is made clear, here, that the inventor believes that the claimed subject matter is the invention.