US 3860320 A
A dangler cable for an electroplating barrel is connected to a ball-like cathode member by stripping the end portion of the cable and inserting the same in a sleeve which is pressed into an undersized tapered socket in the ball-like cathode member.
Claims available in
Description (OCR text may contain errors)
United States Patent 1191 Danner [451 Jan. 14, 1975 DANGLER CATHODE CABLE ASSEMBLY 1,113,973 9/1961 Germany 339/100 Inventor: Robert Banner warren, Mich 671,875 10/1963 Canada 339/100  Assignee: Joseph D. Kinnear, Warren, Mich.
Przmary Examiner-Joseph H. McGlynn  Flled: 9, 1973 Attorney, Agent, or Firm-Barnes, Kisselle, Raisch & 21 Appl. No.: 349,109 Choate  US. Cl 339/100, 339/273 F r  Int. Cl H0lr 11/20 ABSTRACT  Field of Search 339/100, 273
A dangler cable for an electroplating barrel is con-  Refer Cit d nected to a ball-like cathode member by stripping the UNITED STATES PATENTS end portion of the cable and inserting the same in a sleeve which is pressed into an undersized tapered socket in the ball-like cathode member.
FOREIGN PATENTS OR APPLICATIONS 14 Claims, 5 Drawing Figures 568,632 4/1945 Great Britain 339/276 T DANGLER CATHODE CABLE ASSEMBLY This invention relates to a dangler cathode cable assembly of the type used in electroplating barrels.
In electroplating processes employing rotating barrels there is usually provided a cable extending into the barrel through one or both ends thereof at the axis of rotation of the barrel, the cable having a ball-like cathode member secured to its free end within the barrel for conducting plating current through the electrolyte to the workpieces tumbling in the barrel. The ball-like cathode is commonly secured to the end of the cable by soldering, crimping or the like; but, in any event, with conventional practice several problems are frequently encountered with such connections. One of these problems resides in inability to obtain a reliably strong connection between the cathode and the cable in an economical manner. Another problem resides in the fact that with conventional cathode cable connections the corrosive electrolyte attacks the joint between the cable and the cathode and also, through capillary action or otherwise, flows axially through the cable and corrosively attacks the electrical connection between the other end of the cable and the power source (which is usually a bus bar.)
The present invention has for its object the provision of a connection between a cable and a cathode which eleiminates the above problems and also a method of producing the improved connection.
Other features, objects and advantages of the present invention will become apparent from the following description and accompanying drawing, in which:
FIG. 1 is a fragmentary view, with parts broken away, showing one end of a plating barrel employing a cathode dangler cable assembly embodying the present invention;
FIG. 2 is a fragmentary view, partly in section, illustrating the connection between the cable and the balllike cathode;
FIG. 3 is a plan view, partly in section, showing the sleeve member employed in the connection of this invention;
FIG. 4 is a fragmentary view, partly in section, show ing the manner in which the cable is rigidly connected to the cathode; and
FIG. 5 is a fragmentary view, partly in section, showing the manner in which the cathode is clamped and sealed to the cable sheath.
Referring to FIG. 1, an electroplating apparatus is generally designated at 10, this apparatus including an electrolyte tank 12 in which is supported for rotation a plating barrel 14 having a perforated cylindrical wall 16 and an end wall 18. Means (not illustrated) are provided for rotating barrel 14 about its longitudinal axis within tank 12. Wall 18 is provided with a central bushing 20 which is apertured to accommodate a dangler cable 22. Cable 22 is connected at one end to a bus bar 24 and its other end has a ball-like cathode member 26 secured thereto. The cable preferably includes a rotatable coupling 28 adjacent its connection with bus bar 24 which enables the cable to rotate about its longitudinal axis.
Referring to FIG. 2, cable 22 comprises a plurality of spirally wound groups ofwire strands 30 surrounded by an insulating sheath 32. The present invention is directed specifically to the manner in which cable 22 is secured to cathode member 26 with a strong and sealed connection therebetween. This connection utilizes a metal sleeve 34 having a cylindrical bore 36 at one end and an enlarged head 38 at its other end. Bore 36 has a diameter dimensioned to snugly receive the stripped end 40 of cable 22 and the enlarged head 38 forms a cylindrical socket 42 dimensioned for receiving with a snug fit the sheathed portion 44 of the cable directly adjacent the stripped end 40. It will be noted from FIG. 4 that the length of the stripped end 40 of the cable is slightly greater than the length of bore 36. The outer surface of the annular wall 46 of sleeve 34 is connected to the enlarged head by a shoulder 48. The outer surface 50 of wall 46 adjacent the upper end thereof is eylindrical and of uniform diameter while the outer surface 52 adjacent the lower end of bore 36 is of tapered configuration so that the tapered section of wall 46 is progressively thinner in a downward direction. The taper on surface 52 is relatively slight, preferably in the range of about 3 /2 in relation to the central axis of bore 36.
Referring now to FIG. 4, cathode 26 comprises a heavy ball-like member formed with a tapered socket 54. The length of socket 54 is somewhat greater than the length of wall 46. The taper of socket 54 corresponds to the taper of the surface 52 of wall 46. However, the transverse dimension of tapered socket 54 is determined such that the leading end of sleeve 34 is adapted to be freely inserted into socket 54 only partially as shown in FIG. 4. More specifically, the diameter of socket 54 at the upper end thereof is slightly larger (for example 0.050 inch) than the outer diameter of wall 46 at its lower end and is preferably slightly smaller (that is, about 0.010 inch to 0.015 inch) than the diameter of the cylindrical surface 50 of wall 46. It will be noted that wall 46 is relatively thin in relation to the thickness of the wall 56 of cathode 26 which surrounds socket 54. In comparison to wall 46, wall 56 is capable of withstanding exceedingly high stresses without substantial deformation. Within the lower end of socket 54 there is arranged an upwardly projecting pin 58 having a conical point 60 at its upper end.
To connect cable 22 and cathode 26 as shown in FIG. 2, the end of cable 22 is first stripped of sheathing as indicated at 40 and, with the stripped wire strands held as a tight bundle, the stripped end of the cable is manually inserted into and pressed through bore 36 so that sheath portion 44 is snugly embraced and seated in the enlarged socket 42. Sleeve 34 with the cable extending therethrough is then manually inserted into socket 54 of cathode 26 to the position shown in FIG. 4. The partially assembled sleeve and cathode are then positioned between upper and lower die plates 62, 64, respectively, in a suitable press. Die plate 62 has a downwardly opening socket 66 therein which snugly embraces the enlarged head 38 of the sleeve and is provided with a shoulder 68 adapted to bear downwardly upon the upper flat end 70 of the wall surrounding socket 42. Cathode 26 is supported on stationary die plate 64.
Die plate 62 is driven downwardly by the ram of the press with sufficient force to drive the sleeve 34 into socket S4 to the position shown in FIG. 2. As sleeve 34 is driven downwardly into socket 54 wall 46 is displaced radially inwardly around its entire periphery to tightly compress together the wire strands of the stripped end 40 of the cable within bore 36. It will be appreciated that when the cable is formed, although the wire strands are held somewhat tightly together by its sheath, the cross sectional area of the stripped end 40 is actually much greater than the cummulative cross sectional area of the individual wire strands. In view of the fact that approximately the lower half of wall 46 is tapered as at 52 and the upper half is cylindrical as at 50, when sleeve 34 is driven downwardly into socket 54 to the position shown in FIG. 2, where shoulder 48 abuts against the upper end face of cathode 26, the extent to which successive portions of wall 46 are displaced radially inwardly varies along the length of bore 36. More specifically, the relative dimensions of socket 54 and wall 46 are such that the maximum radial inward displacement of wall 46 occurs at the junction 72 between the tapered portion 52 and cylindrical portion 50 of wall 46. The radial inward displacement of wall 46 progressively diminishes in opposite directions from junction 72. Thus, when the sleeve is fully seated in socket 54, the outer surface of wall 46 conforms to the taper of socket 54 and the inner peripheral surface of wall 46 is generally uniformly curved in an axial direction as indicated at 74 so that the thickest portion thereof (the portion designated 76 in FIG. 2) registers axially with the location ofjunction 72 between the tapered portion 52 and cylindrical portion 50 of wall 46. Surface 76 has a smooth, continuous curvature so that there will be no tendency for abrupt shoulders to shear the wire strands as they are compressed radially.
The various dimensions of socket 54 and wall 46 can be determined in relation to the number and size of the wire strands in the cable so that the cross sectional area of the compressed wire strands at the section 76 is substantially equal to or is slightly less than the cummulative cross sectional area of the individual wire strands. The proper relative dimensions of the sleeve and cathode can be visually determined rather than mathematically. The proper amount of compression and radial displacement is achieved when the assembly is transversely sectioned in the plane of junction 72 and the cross section of the wire strands presents a substantially solid circular single metal conductor section as distinguished from a plurality of distinct individual wire strands. When the sleeve is compressed to this extent substantially all the interstices between the originally circular wires are eliminated and the stripped end of the wire is effectively clamped within sleeve 34 while the slight taper on socket 54 and the forced fit of the sleeve therein assures a tight and permanent connection between sleeve 34 and cathode 26. This tight permanent connection is enhanced by the provision of pin 58 which expands the lower free ends of the wire strands outwardly beyond the lower end of sleeve 34 and also displaces in a radially outwardly direction the lower end portions of the wire strands within the lower end of sleeve 34 while the latter is being displaced in a radially inward direction. As shown in FIG. 2, in the assembled condition the lower ends of the wire strands are spaced above the bottom of socket 54. This provides a desired tolerance in dimensions which would otherwise be critical if socket 54 were completely filled by the sleeve and wire conductor.
After sleeve 34 is assembled with cathode 26 the upper end of enlarged head 38 is tightly clamped in sealed relation with the sheath 32 surrounding the wire strands. The can be accomplished in the manner illustrated in FIG. 5. The assembled sleeve and cathode 26 are arranged between a base support (not illustrated) and a die plate 78 having a downwardly opening cylindrical socket 80 sized to snugly receive enlarged head 38 and tapered portion 82 of progressively decreasing cross section. The vertical extent of cylindrical socket 80 is less than the vertical extent of enlarged head 38 so that, as die plate 78 is forced downwardly under pressure, tapered portion 82 displaces the upper end portion of the wall of head 38 radially inwardly to embrace and tightly compress against rubber sheath 32 on cable 22.
The above described connection between the cable 22 and cathode 26 results in several very desirable advantages. In the first place, the sealed connection (generally designated 84 in FIG. 2) between the cathode and the cable effectively precludes any contact between the corrosive plating solution and the wire strands in the cable. Since the inwardly turned upper end of head 38 tightly clamps the cable sheath and since the sleeve is tightly compressed within socket 54,
the corrosive electroplating solution is effectively prevented from coming into contact with the wire strands. Furthermore, the manner in which the cable is attached to cathode 26 in no way impairs the strength of the individual wire strands, as is the case where the end of the cable is crimped to a terminal by conventional crimping tools. Tests have shown that the tensile strength of the connection is far in excess of that which is obtainable by soldering the end of the cable within a socket formed in cathode 26 or by utilizing a crimping operation. Furthermore, the present invention provides a method of connecting a cable to a cathode in a manner which is not only economical but also produces consistently uniform strong connections.
1. In combination, a sheathed electrical conductor cable having a stripped end comprising a plurality of wire strands and means securing the cable to a cathode comprising a metal sleeve having a bore therein which is circumferentially continuous throughout its length and through which the wire strands extend axially, means forming a sealed connection between the cable sheath and said sleeve, said cathode having a tapered socket therein, said sleeve having a tapered outer surface circumferentially surrounding said wire strands and in tight frictional engagement with said socket, said sleeve being subjected by said socket to radially inwardly compressive forces which are transmitted by said sleeve radially inwardly to said wire strands to an extent such that the cross sectional area of one circumferentially continuous portion of the stripped end of the cable within the cathode is substantially smaller than the cross sectional area of the wire portion of the cable disposed axially outwardly of the cathode, said one portion of said stripped end of the cable having the appear: ance of being substantially free of interstices between the wire strands so as to present in section the appearance of a single solid conductor, the taper of said socket being at an angle of not greater than 3% to the axis of the socket, said sleeve being retained in said socket solely by the frictional engagement between the interengaged tapered surfaces of said sleeve and socket.
2. In combination, a sheathed electrical conductor cable having a stripped end comprising a plurality of wire strands and means securing the cable to a cathode comprising a metal sleeve having a bore therein which is enlarged at one end of the sleeve, the sheathed portion of said cable extending into the enlarged portion of the bore, means forming a sealed connection between the cable sheath and said one end of the sleeve, said wire strands extending axially through the smaller bore portion, said smaller bore portion being circumferentially continuous throughout its length, said cathode having a tapered socket therein, said sleeve having a tapered outer surface around the smaller bore portion in tight frictional engagement with said socket, said sleeve being subjected by said socket to radially inwardly compressive forces whereby the smaller bore portion of the sleeve tightly grips the wire strands therein to an extent such that the cross sectional area of one portion of the stripped end of the cable within the cathode is substantially smaller than the cross sectional area of the wire portion of the cable disposed axially outwardly of the cathode, the smaller bore portion of said sleeve defining a passageway therethrough which is of reduced cross section adjacent said one portion of the stripped end of the cable relative to the cross section of the smaller bore portion at the leading end of the sleeve.
3. The combination called for in claim 2 wherein the taper of the socket is at an angle of not greater than 3V2 to the axis of the socket.
4. The combination called for in claim 2 wherein said portion of the sleeve bore of reduced cross section is disposed axially intermediate the ends of the smaller bore portion of the sleeve.
5. The combination called for in claim 4 wherein diametrically opposite sides of the smaller bore portion of the sleeve in axial section are defined by smooth continuous curves which converge from opposite directions at the portion of the sleeve bore of reduced cross section.
6. The combination called for in claim 2 wherein the free ends of the wire strands project into said socket beyond the leading end of the sleeve.
7. The combination called for in claim 6 wherein the free ends of the wire strands terminate short of the smaller end of the socket.
8. The combination called for in claim 6 including a pin projecting into said socket from the smaller end thereof, said pin having a diameter substantially less than the socket and extending axially into said free ends of the wire strands to expand them radially outwardly beyond the leading end of the sleeve.
9. The combination called for in claim 8 wherein said pin extends axially into the leading end of the sleeve.
10. The method of securing a cathode to the end of an electrical cable of the type having a plurality of wire strands enclosed in an insulating sheath which comprises, stripping the sheath from an end portion of the cable; inserting the stripped end portion of the cable into a metal sleeve having two concentric, axiallycontiguous bores therethrough connected by an annular shoulder, the bore adjacent the end of the sleeve into which the cable is inserted having a diameter sized to snugly receive an end portion of the cable with the insulating sheath thereon and the other bore being circumferentially continuous throughout its length and of a smaller uniform diameter sized to snugly receive the adjacent stripped end portion of the cable, the portion of the sleeve through which the smaller bore extends having an outer surface portion which tapers progressively to a smaller diameter in a direction away from the end of the sleeve through which the cable is inserted; thereafter, inserting the free end of the sleeve into a tapered socket in the cathode which is closed at its smaller end and has a diameter at its larger open end sized such that the sleeve is only partially freely insertable therein so that a substantial portion of the sleeve wall surrounding the smaller bore projects axially outwardly from the larger end of the socket; thereafter, applying sufficient axial force on the outwardly projecting portion of the sleeve to drive the sleeve into the tapered socket of the cathode a substantially greater distance, the cross sectional dimension of the cathode being sufficiently large to resist circumferential expansion so that the axially applied force causes the sleeve wall of the smaller bore to circumferentially contract as the sleeve is driven into said socket, the portion of the lastmentioned wall of the sleeve which is adapted to be driven into said socket being shaped in axial section such that said axially applied force causes the metal at one section of said wall to be displaced radially inwardly to a greater extent than the metal at the leading end of the sleeve wall and thus produce a smaller internal diameter at said section of the sleeve than at the leading end of said sleeve, the taper of said socket being such as to cause said sleeve to tightly compress and grip the stripped end of the cable and to cause the sleeve to be tightly locked in the socket of the cathode solely by friction; and circumferentially contracting the sleeve wall of the larger bore into tight sealing engagement with said insulating sheath.
11. The method called for in claim 10 wherein the taper on the sleeve corresponds generally with the taper of said socket.
12. The method called for in claim 10 wherein said one section of said sleeve wall is located axially intermediate the ends of said wall so that the metal in said wall at said section is displaced radially inwardly a greater extent than the metal on axially opposite sides thereof.
13. The method called for in claim 12 wherein the portion of the sleeve wall adapted to be driven into said socket has a cylindrical outer surface on the side of said intermediate section axially opposite the tapered portion of the wall, said cylindrical outer surface having a diameter at least as large as the larger end of said tapered socket so that said axially applied force causes the portion of the sleeve wall within said socket to be contracted radially substantially throughout its axial extent and imparts a smooth continuous curvature in axial section to said smaller bore.
14. The method called for in claim 13 wherein said cylindrical outer surface of said sleeve has a diameter at least slightly larger than the open end of the tapered socket.