US3015509A - Connector device - Google Patents

Description

Jan. 2, 1962 E. w. BOLLMEIER CONNECTOR DEVICE Original Filed March l, 1955 /M/E/v/Q En. WAYNE 5a ME/E2 p faq V.

United States Patent @tice 3,015,569 CONNECTOR DEVICE Emil Wayne Boilmeier, St. Paul, Minn., assignor to Minnesota Mining and Manufacturing Company, St. Paul, Minn., a corporation of Delaware Original application Mar. 1, 1955, Ser. No. 491,342, now Patent No. 2,890,266, dated June 9, 1959. Divided and this application .lune 8, 1959, Ser. No. 818,761

6 Claims. (Cl. 2S7--78) jacent mechanical parts. Such connectors are easily applied, either by hand or by mechanical means, to any of ths usual wire sizes employed in electrical circuitry.

Connector devices illustrating the principles of this invention are further described in connection with the drawing, in which:

FIGURE l represents a side elevation, partly in section, of a wire-connector including an insulating cover;

FIGURES 2 and 3 are cross-sections of the device of FIGURE l, as indicated; y

FIGURE 4 is a longitudinal cross-section of a modified connector without the insulating cover;

FIGURE 5 represents another modification, partly in section;

FIGURE 6 represents a further modification, partly in section, and FIGURES 7 and 8 represent sectional and rear end views of the article of FIGURE 6, as indicated;

FIGURES 9 and l0 represent a still further modification7 in partial section and in end elevation respectively; and

FIGURES 11 and 12 represent details of structures, shown in partial cross-section, which may be employed in place of those of FIGURES 3 and 7.

The device of FIGURE 1 includes a tapered tubular helical coil l0 of spring wire 11 located within a metal shell 12 which is open at the forward end of the coil. The shell 12 is circular in cross-section at the open end, tapering to a triangular cross-section adjacent the opposite end. The circular cross-section at the-forward end of the metal shell and insulating cover is illustrated at section 2 2 shown in FIGURE 2, the corresponding end turn of the coil being omitted for clarity. The triangular section at the rearward end of the Wire-connector is illustrated in section 3-3shown in FIGURE 3 of the drawing. The shell 12 terminates at the open end in a crimped edge 16, which is eflective in permanently retaining the Wire coil 10 within the confines of the shell.

The foremost endrturn of the coil 10, which is adjacent the opening in shell 12, khas an external diameter substantially equal to the internal diameter of the shell at the same area. Subsequent turns of the coil are reduced in diameter, to provide a coil tapered over about one-half its length and cylindrical over the remaining portion. The rearmost end turnof the coil 1.0 of FIG- URE l has an external diameter equal to the diameter of the largest circle which may be inscribed within the triangular cross-section of the shell 12 at that point, as illustrated in FIGURE 3; however the end turn may be of any desired smaller diameter in this modification. In-

Patented Jan. 2 1962 termediate turns are less in diameter than required to fit snugly within the shell and are therefore capable of expansion within the shell. The end of the rearmost turn is extended outwardly from the coil to form a pressure member 35, iitting closely withinl one of the corners of the triangular end of the shell 12. f

An external insulating sleeve 13 tits over the entire coil and shell assembly. The sleeve 13 terminates in a tubular portion 14 providing access to the open end of the metal shell. The material of which the sleeve 13 is made is electrically insulating in character and is liexible and elastic so that the sleeve clings tightly to the shell and so that the terminal tubular portion 14 may conform closely to the surfaces of the insulated Wires which are to be thrust therein.

As illustrated in FIGURE 4, the shell 42 of this modi- -fication of the connector is provided with a second axially centered opening at the triangular end, providing a free axial path through the entire structure. The device is illustrated without the insulating cover; and in this form it is suitable for making running splices as well as terminal or pigtail splices in electrical conductors and for attaching to wires or rods destined for non-electrical uses. However the insulating sleeve 13 of FIGURE l may equally well be applied to the modified device of FIG- URE 4, the closed end of the sleeve being then removed or opened where it is desired to make a running splice. Alternatively, a tubular elastic insulating member open at both ends may be employed with the device of FIG- URE 4, or the completed splice may be'covered with a protective and insulative layer of adhesive tape or compound. f

In the device of FIGURE 4 some or all of the turns or" the coil 40 are separated, whereas the turns of coil It) of FIGURE l are contiguous. Coil 4Q is placed Within the shell 42 under axial compression and expands to fit tightly against the subsequently crimped ends 46 and 47. The end 48 of the wire 41 at the foremost or largest turn is sharp-edged and digs into the metal of the shell 42., when the latter is turned in the removal direction, forming an angular recess against which the wire-end presses, thus permitting the removal of the connector from a splice. The coil terminates as in FIGURE 3.

FIGURE 5 represents a modiiication in which the coil 50 is not axially expanded and is shorter than the shell 52, and the forward-most turn of the coil is tapered as at 58. When the shell is turned in the removal direction, the tapered wire slides past the surface of the shell wall, thus preventing removal of the connector once it has been applied in connecting together a bundle of wires.

The coil 60 of the device of FIGURES 648 is substantially the same as coil 10 of FIGURE l except that the end portion 65 of the rearmost turn does not extend as far from the coil as does the pressure member 35 shown in FIGURE 3. The shell member 62 of FIGURE 6 likewise is similar at the foremost portion to the shell member 12 of FIGURE l, but diiiers at the rearward portion in being in the form of a small circle having opposing ns 63 and 64 as indicated in FIGURE 7. The tip 65 of the rearmost turn of the coil 60 abuts against one of the corners formed by the iin 63 in transmitting torque for advancing the unit onto a wire splice. The fins 63 and 64 are closed at the rearmost ends, and the corresponding rearmost portion v66 of the shell 62 is crimped over the rearmost turn of the coil 60, as indicated in FIGURE 8.

The two-part telescoped shell 92 of the device of FIG- URES 9 and 1G is in hexagonal form, this modification being designed for application with a wrench. The device is useful as a wire-connector, and may also be used as a self-locking nut on threaded rods or the like. The coil spring compression member is normally axially extended, and is inserted within the shell 92 under compression as the two halves of the shell are permanently forced together. The two end turns of the coil 90 will be seen to be of substantially identical diameter, the coil tapering to a smaller diameter at the central turns. Each of the endsof the shell is slotted as at 91 and the slotted portions upset as at 93 to produce internal angular recesses having sides against which the tips 95 of the helix 90 may press. Since the same construction exists at both ends of the connector, the latter may be applied and sub sequently removed as desired. rifhe radially contracting spring maintains the connector in firmly attached relationship to the wire-bundle or rod over which it is applied, until external ltorque is applied for removal.

Grooves or indentations 111 in the cylindrical shell 112 in FGURE ll provide an altcrnative type of angular recess for transmitting torque from the shell to the coil 110 through the wire-end 115. In this structure, as in FIGURE 9, both end turns may be of the same diameter, and the wireend is not extended. The structure is also applicable to coils having a smaller rearmost turn and contained in a tapered conical shell. A ribbed or fluted insulating cover may be placed over the metal shell if desired.

The rearmost turn of the coil 120 of FIGURE 12 is in the form of a triangle fitting snugly within the end portion of the shell 122., which corresponds to the shell 12 of PEG-URE 3. The tip of the wire 121 is here turned inward, rather than outward as in FIGURE 3, and bears against the ends of an inserted wire-bundle to indicate a `completed installation. The triangular form of the terminal turn provides for effective torque transmission without distortion of the shell such as is sometimes caused by the protruding wire-end 35 of FIGURE 3 or the wireend 65 of FIGURE 7 under excessive torque.

In operation in the splicing of insulated copper conductors, using the connector of FIGURE l, the tips of the conductors are first freed of insulation and are bundled or lightly twisted together. The bundle of wires is then pushed into the open end of the wire-connector, through the tubular portion 14 of the sleeve 13 and through the open end of the shell 112, while the entire connector is rotated. The angular shape of the rearward portion of the shell serves to provide an effective grip for manual or mechanical rotation of the connector and also serves to transmit the rotating movement to the coil by way of the pressure member 35. Pressure of the wire-ends against the interior or" the spring wire coil 10,

combining with the rotating movement of the coil, causes the central turns of the coil to expand under tension and to grip the wire-ends, with the result that the coil is screwed onto the wire-ends to form a compact and permanent splice. Electrical contact between the wire-ends and mechanical stability of the entire splice is permanently maintained, even under extreme intermittent tension and vibration, due to the high compression provided by the expanded spring wire coil. The fiexible coil is protected from deformation by the trough metal shell 12, which also serves as a smooth uniform base for the flexible elastic insulating cover. The insulating cover provides effective electrical insulation for the entire assembly; but this component of the structure is not relied upon either for mechanical protection of the connection or for mechanical advantage in the application of the device to the wire-ends. The entire structure is neat in appearance, having smooth contours and fitting tightly to the insulated portion of the wires.

A given size connector permits the connecting of a wide range of sizes and numbers of wires. For any given splice, a connector should be selected in which the helical coil has an entrance opening capable of accepting the bundlel of wire-ends and tapers to a diameter substantially less than that of a circle just capable of containing the bundle of wire-ends.

Application of the connector to wire splices may be accomplished either by hand or by mechanical operations. The shape of the wire-connector is such that the device may be easily applied and twisted with the lingers, or may readily be temporarily fitted into a suitably shaped socket in a speed wrench, thereby mechanically to provide the necessary twisting torque required for the appli# cation of the connector to the bundle of wire-ends.

The wire-oonnector of this invention is particularly adapted for forming end or pigtail splices between small `copper wires. It may, however, be employed with much larger copper or other metallic conductors or with wires or rods employed for other than electrical purposes.

Particularly for high speed mechanical application the connectors illustrated in FIGURE l may be provided in the form of a continuous bar or coil, with the sleeve 14 of each following connector engaging the triangular tip of the preceding connector. The har thus formed is fed into the applicator, each foremost member being removed and rotated onto successive wire-bundles.

The connectors of this invention may be pre-filled with insulating or protecting pastes or other flowable plastic material. Silicone greases, mineral oil greases, soft and plastic rubbery butadiene-styrene polymers, and other materials of analogous physical properties are useful. The inclusion of powdered zinc or aluminumA in such compositions is of assistance in providing improved electrical contact, particularly in the case of oxide-coated aluminum wires. The adherent greasy plastic material fills all voids around the conductor terminals and affords improved mechanical, chemical and electrical protection to the wire-splice. Softer materials may be retained within the connector by lightly sealing over the open end or ends, e.g. with hardened wax or with a thin membrane of the same composition as the insulating sleeve.

The several structures described andvillustrated, and other analogous modifications, may obviously be combined in other ways to provide additional specific but non-limiting structures and examples. f

What is claimed is as follows:

kl. A connector device capable of being threadably axially advanced over a wire or rod-like member to provide a firm compression grip thereon and comprising a tapered helical spring-wire fastening element and a rigid cover member centrally open at each end, said fastening element being retained within said cover member and having end turns fitting snugly within the corresponding ends of said cover member and having intermediate turns of a diameter less than the internal diameter of said cover member and expandable under spring tension as said connector device is advanced over said wire or rod-like member, said end turns terminating in wire-tips accessibly located for application of force thereagainst in threadably rotating said fastening ele-ment, said rigid cover member being provided at each end with a single inwardly extending projection for bearing against the corresponding wire-tip in transmitting torque from said cover member to said fastening element.

2. A connector device capable of being threadably axially advanced over a wire or rod-like member to provide a firm compression grip thereon and comprising a tapered helical spring-wire fastening element and a rigid cover member centrally open atleast at the forward end and having a single inwardly extending projection at least at the rearward end, said helical element being retained within said Vcover member and having a foremost turn snugly fitting within the forwardv section of said cover member, a rearmost turn snugly fitting within the rearward section and with the wire-tip in position for torquetransmitting pressure-contact with said projection, and a plurality of intermediate turns of a diameter less than the corresponding internal diameter of said cover memberv and expandable under spring tension as said conductor device is advanced over said wire or rod-like member.

3. A wire-connector comprising: a spring-wire helix having a plurality of convolutions providing a forward opening of enlarged diameter adapted to receive a wirebundle, a medial portion of substantial length having a bore of reduced diameter and expandable under spring tension produced on threadably advancing said helix onto a said wire-bundle, and a rearward end turn terminating arcuately in an end abutment; and a sheet-metal Shield encasing said helix in endwise compressive peripheral contact at the forward and rearward ends of said helix and having spaced clearance with said medial portion of Said helix for permitting expansion thereof, said shield having an internally extending projection lying in the arcuate path of said end abutment for engagement therewith in transmitting torque from said shield to said helix during threadable advance of said wire-connector.

4. Al wire-connector comprising: a plurality of convolutions of spring-wire forming a tapered continuous helix having a forwardopening of enlarged diameter adapted to receive a wire-bundle, a medial portion of which at least a substantial segment has a bore of reduced diameter and is expandable into threaded gripping relation about a wire-bundle inserted through said forward opening, and a trailing last convolution terminating arcuately in an end abutment; and a sheet-metal shield having a forward and a rearward inwardly shouldered opening encasing said helix in retaining endwise contact and having spaced clearance with the reduced-diameter medial portion of said helix, and said shield having an internally extending projection lying in the arcuate path of said end abutment for engagement therewith in transmitting torque from Said shield to said helix during threadable advance of said wire-connector along said wire-bundle.

5. A wire connector comprising: a plurality of convolutions of continuous spring wire formed into a helix having forward and rearward openings of enlarged diameter and having for a substantial portion of its medial length a bore of reduced diameter adapted to be expanded into threaded gripping relation about a wirebundle inserted at either of said openings, said helix having a leading rst convolution and a trailing last convolution each terminating arcuately in an end abutment; and a sheet metal shield having both a forward and a rearward inwardly shouldered opening encasing the helix in retaining endwise contact and having spaced clearance therewith at the medial portion thereof, said shield having an internal offset abutment lying in the arcuate path of the end abutment of each of said rst and last convoluticns for transmitting torque from said shield to said helix in either direction.

y6. A spring-connector comprising a plurality of convolutions of continuous spring-wire forming a helix having terminal openings of enlarged diameter and having for a substantial portion of its medial length a bore of reduced diameter adapted to be expanded against the resiliency of the medial convolutionsfof said helix and including a lea-ding rst convolution and a trailing last con- Volution each terminating arcuately in an end abutment; and a hexagonally contoured sheet metal shield having both a forward and a rearward inwardly shouldered opening accessibly encasing said helix in retaining endwise contact and having spaced clearance therewith at said medial convolutions to permit resilient expansion thereof and having an internal offset abutment lying in the arcuate path of the end abutment of each of said first and last convolutions for transmitting torque from said shield to said helix in either direction.

References Cited in the file of this patent UNITED STATES PATENTS 704,869 Fischer et al. July 15, 1902 1,657,253 Fortin Jan. 24, 1928 1,830,920 Sundh Nov. 10, 1931 2,022,946 Steampli Dec. 3, 1935 2,792,560 Bollemeier May 14, 1957 2,861,826 Schinske Nov. 25, 1958 FOREIGN PATENTS 678,944 Great Britain Sept. 10, 1952

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