|Publication number||US3743087 A|
|Publication date||Jul 3, 1973|
|Filing date||Aug 10, 1970|
|Priority date||Jul 3, 1968|
|Publication number||US 3743087 A, US 3743087A, US-A-3743087, US3743087 A, US3743087A|
|Original Assignee||Amp Inc|
|Export Citation||BiBTeX, EndNote, RefMan|
|Patent Citations (8), Referenced by (10), Classifications (11)|
|External Links: USPTO, USPTO Assignment, Espacenet|
United States Patent 191 Wise COLD FORMED PLASTIC CONNECTOR HOUSING  Inventor: Joseph Agusta Wlse,Mechanicsburg,
 Assignee: AMP Incorporated, Harrisburg, Pa.
 Filed: Aug. 10, 970 [211 App]. No.: 62,697
Related U.S. Application Data  U.S. Cl 206/56 AB, 174/87  Int. Cl. 13651! 73/02, HOlr 5/10  Field of Search 206/56 A, 56 AB, 206/65 F; 174/87  References Cited UNITED STATES PATENTS 2,872,505 2/1959 Ustin 174/87 2,526,277 10/1950 Rogoff... 174/87 2,823,249 2/1958 Curtiss 174/87 2,964,171 12/1960 Chadwick 206/56 AB 3,170,160 2/1965 Burniston 206/56 AB 3,241,658 3/1966 Anderson 206/56 AB 2,823,250 2/1958 OKeefe 174/87 1,736,379 11/1929 Sommer 174/87 [451 July 3, 1973 Raring, John R. Hopkins, Adrian J. La Rue and Jay L. Seitchik  ABSTRACT A method and means is disclosed featuring a cold forming of plastic bodies in the form of buttons, pellets or other simple shapes into more complex functional configurations for housing and insulating electrical terminals, mechanical fasteners and the like. The plastic bodies are integrally joined to a thin flexible carrier to facilitate processing. Cold forming is effected by dies brought to bear against the bodies with one of the dies carrying a connector element which forms part of the working die surface. The final forming of the housing deposits or embeds the connector element within plastic material. By making the initial molded configuration of a body topographically similar to the final configuration to reduce the extent of extrusion along a given axis the resulting housing may be made to better withstand subsequent deformation for crimping purposes to terminate electrical leads within the terminal and housing or mechanically fasten other elements together.
3 Claims, 6 Drawing Figures PAIENIEDJUL3 I975 SHEEI 1 BF 2 INVENTOR. JOSE PH AGUSTA WISE Pmmmm' ms SHEET 2 0F 2 INVENTOR. JOSEPH AGUSTA WISE BYW COLD FORMED PLASTIC CONNECTOR HOUSING RELATED CASES This case is a continuation-in-part of Ser. No. 742,427 filed July 3, 1968, and now US Pat. No. 3,606,000, in the name of Joseph Agusta Wise and entitled THERMOFORMED PLASTIC COVERED CONNECTORS, and a continuation of Ser. No. 800,682 filed Feb. 19, 1969 and entitled COLD FORMED PLASTIC CONNECTOR HOUSING and now of course abandoned.
BACKGROUND OF THE INVENTION Many types of electrical and mechanical connectors are comprised of a plastic insulating housing containing within at least a portion thereof a metal sleeve adapted to receive elements such as a wire or wires to be permanently joined by deformation of the sleeve through forces applied to the housing. One widely used device of such construction has a conically shaped plastic housing with a sleeve of metal contained in one end and with the other end open to receive the stripped ends of two or three wires which are then terminated together by a deformation of the sleeve of metal through forces applied to the plastic. U. S. Pat. No. 2,823,250 to M. F. OKeefe discloses an example of the foregoing.
By and large, with respect to connectors of the foregoing type, present-day manufacturing practice calls for a molding of the connector housing followed by insertion of the metal sleeve as a separate step. The housings are typically injection molded using molds containing 10, 20, 30 or more housing cavities; the large number being necessary for economy. Complex multicavity molds are expensive to build, to maintain and numerous problems attend production use caused by the required network of sprues, ventholes, and the like, leading to and from the cavities. A substantial amount of plastic scrap may be expected. Furthermore, since the plastic must be injected under relatively precise temperatures and pressures and caused to flow without sticking throughout the mold surfaces, set-up and close-down times are relatively long.
As an additional point, for high production usage, it is frequently desirable to place the loosepiece parts produced by injection molding on some form of carrier such as a tape capable of being utilized in an automatic machine. This adds to the cost of the product and substantially limits its utility.
SUMMARY OF THE INVENTION The present invention relates to a method and means for cold forming plastic into housings for electrical terminals, connectors, mechanical fasteners and the like.
It is an object of the present invention to provide a method for forming housings for electrical terminals, connectors and mechanical fasteners in a manner which is less expensive than heretofore available. It is another object to provide a method for forming plastic housings through the use of dies and cold working plastic material. It is yet another object to provide a method of cold working plastic material into a series of housings mounted on an integral carrier which may be utilized to advantage for inventory, transportation, and final installation by automatic equipment. It is still another object of the invention to provide an assembly of plastic and connector elements utilizing the connector element in conjunction with other die surfaces to form the plastic element into a housing for such assembly. It is a further object to provide a cold formed, multipart, preinsulated electrical terminal, connector or mechanical fastener.
The foregoing objects are attained by the invention through the use of dies, closed together against plastic bodies of a simple configuration into a more complex configuration defining housings without the usual application of temperature and/or pressure employed in injection molding or extrusion of a molten plastic base material. The web containing plastic bodies is premolded or otherwise formed in a strip to facilitate automatic manufacturing techniques much like a metal stamping operation. The finished housings formed on the web are in a preferred embodiment left joined thereto with the web then being used as a carrier for processing. In one embodiment metal sleeve elements are positioned on one of the pair of mating die surfaces to serve as part of the plastic working surface during cold extrusion with the sleeve being embedded to be left within the housing upon die separation. In a preferred embodiment of a terminal adapted to be crimped onto the ends of the wires the plastic body is given an initial shape which has been better found to withstand crimping forces applied thereto to deform the metal sleeve contained therewithin.
In the drawings:
FIG. 1 is a perspective view showing the invention method and means with a plastic web containing plastic bodies being fed from left to right past a die station; the dies being shown separated and the upper die being shown in partial section;
FIG. 2 is a side and elevational view showing a preferred body configuration;
FIGS. 3A, 3B, and 3C, show initial, intermediary and final positions of working dies, respectively, the upper dies being shown in partial section; and
FIG. 4 is a perspective view of a terminated electrical connector.
DESCRIPTION OF PREFERRED EMBODIMENT OF THE INVENTION Referring now to FIG. 1, a source of thermoplastic material 10 is shown being fed from the left toward and through a die station comprised of a pair of movable dies 20 and 32, supported and driven for reciprocating movement along the axis indicated by the arrows. The material 10 is comprised of a web 11 carrying discrete cylindrical bodies 12 suitably spaced to facilitate working of the metal. Each body 12 has a circular recess 13 in the bottom, as shown in FIG. 3A. The means for mounting and moving the material I0 and the dies 20 and 32 is not shown, but may be understood to be similar to means employed in the metal stamping arts, in terms of drive, displacement and feed. To the right of the tooling shown in FIG. 1 are finished assemblies 16, each comprised of a plastic housing 14 (formed from a body 12) containing a connector element in the form of a metal sleeve 18 locked therein. As can be discerned from FIG. 1, sleeves 18 are positioned on the lower die 20 prior to die closure and material forming.
The material forming operation is shown in FIGS. 3A, 3B and 3C. In FIG. 3A a plastic body 12 is shown positioned beneath the cavity 36 of upper die 32 with the lower die 20 moved to engage a lower recessed surface 13 of the body 12. The recess 13 serves to relieve the web from the forces applied to deform 12. The V- shaped section shown in phantom in FIG. 3A relates to an alternative plastic body configuration as depicted in FIG. 2, which will be discussed in greater detail hereinafter. As can be seen from FIG. 3A, lower die includes a generally cylindrical base portion 22 carrying a conical portion 24, which in turn carries a cylindrical portion 26. Extending from 26 is a cylindrical portion 30 of a diameter to receive sleeve 18, leaving a portion of 30 extending above the end of the sleeve. Sleeve 18 rests upon a step 28 which is the upper surface of 26. The dimensions of 30 relative to the dimensions of 18 are such that 18 is slidingly fitted thereon. Die cavity 36 has a complementary shape relative to the configuration of die element 20 while carrying a member 18 to define a desired housing shape. FIG. 3B shows die 20 moved upwardly relative to 32 to cause a forming of body 12 by an extrusion and working of the material thereof up into the cavity 36 and down against the surface of sleeve 18 and the upper portion of 30. FIG. 3C shows a completed closure of die 20 into cavity 36 with the material of 12 now worked into a final configuration forming a housing H of a connector assembly 16. As can be discerned from FIG. 3C, the material of 14 (12) is formed in around the lower edge portion of 18, such portion being shown as 19 in FIG. 3C. This serves to lock the sleeve within the housing. As can also be discerned from FIG. 3C, web 11 is left intact to form a strip. Web 11, as also shown left intact in FIG. 1, may be utilized as a carrier; not only for production purposes, but for storage, inventory, transportation and utilization in automatic equipment, as in an automatic terminal crimping machine. The strip carrying assemblies 16 may be reeled in some suitable fashion permitting large numbers of connectors to be carried in a relatively small space. The invention also contemplates that the carrier may be wider than that shown to position arrays of bodies in parallel for use with sets of die pairs mounted in parallel.
I have discovered that many plastic housing configurations of types previously formed by injection molding techniques may be essentially cold formed from a simple body or block of plastic directly in stamping dies to a high degree of accuracy while still maintaining characteristics in the plastic material adequate to achieve the function required for electrical connectors and mechanical fasteners. In an actual sample like that shown in FIGS. 1 and 3A-3C, the body 12 was approximately 0.425 of an inch in diameter and 0.210 of an inch high and was formed of Zytel No. 1.01, a readily available nylon product of E. I. Dupont deNemours Company Incorporated. In such actual embodiment the body 12 was initially molded along with web 11 of the same material approximately 0.010 of an inch in thickness and 0.625 of an inch in width. Based upon my experience with this thermoplastic material, other thermoplastic materials, including those in the polyolefin family, could be similarly worked. Cold forming by dies of the configuration shown was tried at relatively high rates (with a press running at 300 strokes per minute) or at very slow rates of forming (the flywheel of the die press being rotated manually through a cycle).
For terminals, connectors or fasteners which require deformation of a metal structure contained within a plastic housing it has been found preferable to utilize an original body shape which can be formed with minimum material working along the axis of material displaced by deformation. With respect to the assembly housing 16 heretofore discussed a preferred original body configuration is shown in FIG. 2. There a strip 40, includes a web 42 carrying a series of bodies 44, which are generally conical in shape and include an interior recess 46. Such recess reduces material working and relieves the web 42 from forces working 44. FIG. 3A shows a body 44 positioned between dies 20and 32. By having the original body of such configuration the plastic material is worked considerably less along the lengthwise axis of dies 20 and 32 then in the previous embodiment. As one result the plastic housing 16 is left with appreciably greater strength and resistance to cracking relative to crimping forces applied to the region of the housing surrounding sleeve 18. The arrows in FIG. 4 show the axis of force application used to crimp the connector. These forces are usually applied by a tool which inelastically deforms the plastic and sleeve 18 from a cylindrical configuration to a generally oval configuration relative to a cross-section taken through sleeve 18 and the housing relative to the length axis of the assembly.
In the embodiment shown in FIG. 1, bodies 12 and thus the complete assemblies 16 are joined by an integral web of plastic material 11. The invention contemplates the placement of bulk plastic bodies to form housings in series on a plastic web or carrier which is integral in the sense of being molded with the bodies or joined thereto by an adhesive or by plastic welding or the like. If a web having discrete plastic bodies joined thereto is used apertures in the web may be provided aligned with recesses like 13 and 46 to prevent the web from being torn by the dies in working the bulk material. The web may also be punched with slots if desired to provide processing and field use.
While not shown, it is contemplated that the formed assemblies may be severed from the web to be packaged in a loose-piece form if desired.
The invention, as heretofore described relative to specific connections, contemplates in one aspect the forming of plastic housings into which elements are inserted to provide an operable connector assembly. While metal sleeves have been disclosed as such elements, metal springs, clips or even plastic members such as nuts, washers and the like are contemplated. The invention also contemplates that in certain applications the housings may be formed prior to element insertion, the dies defining the final shape of the housing and the element fitted and secured therein as a separate step.
The invention as taught thus contemplates a carrier with simple body shapes usable to provide a variety of different housing shapes or a carrier with a specialized body shape usable for a specific housing as alternatives dependent upon preference and application requirements.
Havingnow disclosed my concept for a new method and means in terms intended to enable a preferred practice thereofin its several modes and embodiments, l define what is believed inventive through the appended claims.
I. As an article of manufacture, a thin web of flexible and reelable material carrying a series of discrete electrical connector assemblies thereon, each assembly comprising a generally tubular plastic housing projecting from one surface of said web and being closed at the end thereof remote from said web, and a metallic formable material for crimping the sleeve into engagement with conductors adapted to be inserted in said sleeve.
3. An electrical connector according to claim 2 in which the housings and web are of the same material with the open end of each of the housings being integral with the web.
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|U.S. Classification||206/717, 174/87|
|International Classification||B29C67/00, B29C63/00, B29C51/12|
|Cooperative Classification||B29C51/12, B29C63/00, B29C67/0029|
|European Classification||B29C63/00, B29C67/00F, B29C51/12|