US2792560A

US2792560A - Wire-connector

Info

Publication number: US2792560A
Application number: US343832A
Authority: US
Inventors: Bollmeier Emil Wayne
Original assignee: Minnesota Mining and Manufacturing Co
Current assignee: 3M Co
Priority date: 1953-03-23
Filing date: 1953-03-23
Publication date: 1957-05-14
Anticipated expiration: 1974-05-14

Description

May 14, 1957 E. w. BOLLMEIER 2,792,560

WIRE-CONNECTOR 3 Sheets-Sheet 1 Filed March 25, 1953 IN VEN TOR.

W, W 5% r y 7 E. w. BOLLMEIER 2,792,560

WIRE-CONNECTOR 3 Sheets-Sheet 2 Filed March 23, 1955 IN VEN TOR.

' May 14, 1957 E, w, BbLLMEIER 2,792,560

WIRE-CONNECTOR 3 Sheets-Sheet 3 Filed March 25, 1953 k; /36 w t" INVENTOR.

#TTOFNFYB United States Patent WIRE-CONNECTOR facturing Company, St. Paul, Minn., a corporation of Delaware Application March 23, 1953, Serial No. 343,832

Claims. (Cl. 33967) This invention relates to wire connectors for mechanically fastening the ends of solid or stranded electrical wires, guy-wires, rods, and analogous members to rivets, bolts, other rods or wires, etc. The connectors are easily and rapidly attached and form a strong and self-tightening connection with the wire or other member. Soldering or brazing is avoided. The connectors are fully effective with both aluminum and copper wires as well as wires or rods of iron or steel, wood, plastics, and various other materials. They have been found particularly effective in providing terminal lugs for solid or stranded alminum, copper, or alloy control cables, electrical conductors, and guy wires in aircraft.

In the drawings, Figure l is a plan view of the terminal lug component of one species of .my wire-connector, Figure 2 is a plan view, partly in section, of the compressor component of the same connector, and Figure 3 is an end elevation of the compressor component of Figure 2. Figure 4 is a side elevation, partly in section, of the article of Figure 1, and Figures 5 and 6 represent modification of the article of Figures 2 and 3. Figure 7 represents in perspective the assembled connector of Figures 1 and 2, together with a portion of a stranded insulated conductor to be connected thereto, and Figure 8 represents in perspective the completed assembly of connector and stranded conductor.

Figure 9 represents in perspective another species of my novel wire-connector ready for application in forming a T-connection between a bus bar and a solid insulated conductor, the completed assembly being shown in perspective in Figure 10. A further species of wire-connector is shown in perspective, ready for application in Figure 11 and as assembled on a conductor in Figure 12.

Other compressor components which may be substituted for those of Figures 2 or 5 in assemblies such as illustrated in Figures 7, 9 and 11 are represented in side elevation, partly in cross-section, in Figures 13 and 14; in plan view in Figures 19 and 21; and in perspective in Figures 16 and 23. Figure is a sectional end view of the compressor unit of Figure 14, and Figures and 22 represent end elevations of the compressor components of Figures 19 and 21 respectively. Figures 17 and 18, and also 24 and 25, represent, in perspective and in some instances partly cut away, applicator tools for use with compressor elements shown respectively in Figures 16 and 23.

The terminal lug 15 of Figures 1, 4, 7 and 8 is designed specifically for connection to a binding post or bolt as in attaching an end of an electrical conductor to an instrument panel or in fastening a guy wire to an anchorbolt. It consists of a fiat annular ring 10 forming one end of a solid shank member 11, the other end of the shank member being partly cut away and terminating in an externally threaded thin tubular section 12. The intermediate portion of the shank has a gradually increasing external transverse dimension and forms an inclined trough surface 13 extending from the lower inter'ior of the tubular section 12 to the upper exterior of 2,792,560 Patented May 14, 1957 the central shank section as shown. The upper surface of the shank extending from the upper portion of the trough surface 13 carries a series of low ridges 14.

The threads formed in the exterior surface of the tube 12 preferably have a semicircular cross-section designed to match the cross-section of the spring-Wire 20 of which the compressor component 26 of Figure 2 is constructed. This compressor component is made in the form of a short helix having a single forward turn 21 with an inside diameter substantially equal to the outside diameter of the tubular portion 12 of Figure l, and with several additional turns 22 of somewhat reduced diameter. The rearward turn terminates in a tangential extension 23 which in turn terminates in a single coil 24, thus forming a handle member 27. An arcuate notch, indicated in the drawing at 25, is formed in the wire 20 at the juncture of the handle member 27 and the rearward of coils 22, the notch preferably being at the end of the helix and in a plane passing through the longitudinal axis of the helix and parallel to the extended portion 23 of the handle 27, as is shown more clearly in Figure 3. The angle of arc of the notch, cc, is preferably slightly more than onethird the circumference of the wire 20, about 160 degrees being found most suitable, and for spring steel or equivalent wire the depth of the notch varies from about .002 inch, for wires of about .03 inch diameter, to about .005 inch for wires of about .10 inch or larger diameter.

The handle portion 57 of the compressor member of Figures 5 and 6 differs from that of Figures 2 and 3 in extending tangentially from the terminal coil at the notched area for a short distance and then making a right-angled turn to form a lever arm as shown, the change being necessitated by the addition to the compression member of an outer insulating cover 50, of which section 66 is shown in Figure 6. The tangential portion 61 of the handle member 57 is seen in Figure 6 to pass through a slot extending inwardly from the adjacent end of the cover 50, and indicated in the drawing at 62. The forward coil 51 and rearward coils 52 of Figure 5 correspond to

coils

21 and 22 of Figure 2. The arcuate notch 55 is at the end of the helix and in an axial plane parallel to the lever arm of the handle.

The connector of Figure 7 is assembled ready for use by screwing the helical compressor member 26 of Figure 2 on to the threaded tubular portion 12 of the lug of Figures 1 and 4. The full size of the forward coil 21 permits it to be easily started on the threaded tube 12. Pressure applied to the lever arm of the handle member to rotate the helix then advances the latter along the matching threaded tube, the movement being facilitated by expansion of the coils 22 under the pressure exerted.

In forming a connection between the connector 70 and the bare terminal portion 71 of the insulated stranded conductor 72 of Figure 7, the conductor tip is first inserted through the tubular section 12 carrying the compressor member 26, with the ends of the strands ac1 vancing along the inclined trough 13 and over the ridged portion of the shank 11. The combination of the stranded conductor and the intermediate portion of the shank pro vides a gradually increasing effective diameter which reaches a final value somewhat greater than the internal diameter of the compressor member in its unstressed condition.

The compressor member 26 is then caused to advance past the tubular portion 12 and the trough portion 13, and over the spread-out tips of the wire strands of the portion 71 of the conductor and the central ribbed shank section 11 of the connector, by a turning motion imparted through the handle member as before, the now substantially expanded helix finally coming to rest over the central shank portion and the tip portions of the wire strands The handle 27 is then easily removed, as illustrated in Figure 8, by sharply forcing the end coil 24 in a direction away from the fiat ring iii, in a plane of the longitudinal axis of the helix, andwith the tangential extension 23 approaching cross-section of the notched area and causing torsional breakage of the wire at that point.

The considerable tension of the expanded helical coi s 21, 22 holds the conductor strands in firm contact with the shank 11 of the lug, and the projections 14 assist in preventing slippage between conductor and lug. The resulting connection is strong and permanent, any attempted removal of the conductor merely serving to tighten the grip of the tensioned wire coils.

By the term effective diameter, as used hereinabove in connection with the combination of lug and conductor, is meant the diameter of the smallest circle which may be made to fit around the part or combination of parts under consideration, the cross-section of which may be, and usually is, irregular rather than circular.

Where a covered or insulated connection is desired, the completed connection may be wrapped with adhesive tape. Alternatively, the covered compression member 56 of Figure may be substituted for t e exposed member 26 of Figure 7 to provide a self-insulating connector.

covered by the insulating cap 50.

The connector 90 of Figures 9 and is designed for forming a T-joint between two wires or cables such as a bus-bar 100 and a solid insulated wire. The terminal lug 91 fits around the bus-bar 100, the free tip 92 then closely approaching or contacting the base 93. The trough-like shank 94 is tapered sufiiciently so that, with the end of the solid conductor 101 inserted through the eifective diameter of the shank and conductor together becomes greater than that of the tubular section connection with Figures 2 and 3. The connector is shown installed, and with the handle Q3 removed, in Figure 10, with the helix 97 serving both to bond the conductor 101 to the connector and to seal the terminal lug 91 around the bus-bar 160.

The compressor member 116 of the connector 110 of Figure 11 is situated so as to advance toward the wire 111 and away from the connecting lug 112 in forming a connection. The wire 111 is sealed within a plurality of fitted

segments

113, 114 by the tension of the expanded helical coil 117, as shown in the completed assembly of Figure 12. The edges of segment 114 of connector Ht} fall inside the edges of segment 113, as shown in Figure 12. The segments are circumferentially ridged on the inner surfaces, and are of such size and shape that the effective diameter of the unit at the tip and with the wire 111 in place is somewhat greater than that of the tubular shank 118, so that the coil 117 must expand in advancing from the position shown in Figure 11 to that of Figure 12. The segments may alternatively be fitted in the manner of the jaws of a collet chuck, the adjacent edges of the several sections being slightly separated from each other when the wire 111 is inserted and the sections pressed into place. The shank 118 may be externally threaded if desired, but the tension of the compressor member-116 is ordinarily suflicient to produce slight valleys and ridges in the shank surface, the compressor thus acting like a self-threading nut. In this structure, the compressor 116 is preferably preexpanded, placed around the shank 118, and then permitted to contract. Consequently the several coils of the helix normally are each of the same diameter. foremost coil or coils may be made greater than that of the rearward coils if desired. The wire of which the compressor unit is constructed is torsionally arcuately notched at point 126, so that the handle 119 may be re-' moved from the assembly by twisting, as previously described in connection with Figures 2 and 7, except that in this case the tip of the handle is pressed toward, rather than away from the connecting lug 112.

Figure 13 illustrates .another example of a compressor unit 13% which may be used to replace the insulated compressor 56 of Figure 5. A doubly expanding spring wire helix 132 is held within a plastic insulator shell 132, the rearward tip 133 of the helix 131 extending outwardly just sufficiently to engage the inner surface of the shell 132. Twisting the shell, which is facilitated by the presence of external ridges 134, then screws the helix forward and expands it against frictional resistance offered by an insert such as the combination of wires and

connector shank

8 or 10. Releasing the twisting force then permits the helix 131 to contract and tightly grip the enclosed inserts, thus forming a tight and completely insulated connection.

The forward tip 135 of the compressor helix 131 may also be somewhat extended so as to pres-s into the shell 132, in which case the helix may subsequently be removed from a connector by simply twisting the shell 132 in the reverse direction; or the tip 135 may be flattened or otherwise prevented from catching on the interior surface of the shell, in which case removal of the compressor unit by twisting becomes virtually impossible. In either case, the shell 132 may be removed by forcefully sliding it from the completed connection.

The insulated compressor member 13% is particularly useful as a component of a connector similar to that of Figures 7, 9 or 11. It is also useful for joining a plurality of wires, as in of parallel wire ends, having an appropriate effective diameter somewhat larger than the smallest internal diameter of the helix prior to application, is inserted within the forward end of the compressor helix 131 which is then screwed on to the bundle by twisting of the insulating cover 132. The tension imparted to the helix as it is twisted and expanded over the-bundle of wires is sufiicient to hold the wires in intimate contact and to prevent their removal. In order to provide complete insulative protection, the rearward end of the tubular insulating cover may for such applications he closed with a tightly-fitting plug 136, applied either before or after the splice is completed. The shell 132 may conveniently be made of tough resinous material, e. g. phenolic resin; or, where the application does not require electrical insulation, aluminum or copper or other suitable material may be used.

The compressor member of Fi ure 16 is quite similar to the compressor member 131 of Figure 13, except that only a single turn 1161 is expanded in diameter at the rearward end. Such a compressor is equally as effective as the doubly expanding compressor member 131 in the article of Figure 13; and either members may also be used without the insulating sleeve 132, for example by utilizing a removable applicator such as are illustrated in Figures 17 and 18. The applicator of Figure 17 consists of a tubular portion 171 and The bore of the tubular portion is slightly larger than the rearward coil fol of the compressor 169, but slightly smaller than the coil or coils, so that the applicator the length of the compressor.

thetubular portion 171 is broken ring sharp-edged paraxial lands with the extended wire tip of the extreme forward will slip over most of The interior surface of up into regularly occur However the diameter of the making a pig-tail splice. The bundle and grooves, forming coil 161 a ratchet ar-' rangcment by which an alternate forth-and-back twisting motion applied to the applicator member is converted to a forward screw motion in the compressor member. With the latter tightly in place on the connector or splice, the applicator member may be easily slid backwardly from the compressor member.

The split applicator 150 of Figure 18 operates in analogous fashion, and has the further advantage that it can be opened and removed from a wired connector or a running splice as well as from a pig-tail splice. The split applicator consists of two half-cylinders hingedly joined along one side and extended in an axial direction at the other. One of the half-cylinders is slightly smaller in radius than the other, thereby providing an interior paraxial shelf 181 against which the tip of the rearward coil 161 of the compressor member 160 presses during application.

Force may be applied to the compressor member in still other ways, for example by means of a short axial projection and an appropriate applicator tool as will now be described in connection with Figures 23-25. The compressor member 239 of Figure 23 terminates at the rearward end in an extended radial stub 231 which enters the slot 241 formed in the conical wall of the applicator tool 240 of Figure 24, shown partly in section, or rests against the side of the shelf 252 formed within the applicator tool 250 of Figure 25 by the bent-over edge of the springy sheet metal 251 of which tool 250 is constructed. As illustrated,

tools

240 and 250 are particularly useful, with compressor member 230, in forming pig-tail splices; however they may obviously be modified for application to the making of running splices and the fastening of wires or cables to terminal connectors, as has already been indicated in connection with the applicators 170 and 1841 of Figures 17 and 18.

Another means of applying the requisite force to the compressor member is illustrated in Figures 19 and 20, wherein the handle member 192 extends from the rearward coil 191 of the compressor member 190 with one edge substantially forming an extension of a radius of said coil, the spring wire of which the article is constructedbeing torsionally notched at the end of the helix and in the axial plane passing through the same extended radius, as shown at 193. After the compressor member 190 is in final position, for example in the position of the member 26 of Figure 8, the handle 192 is easily removed by sharply forcing the end portion 194 in the forward direction so as to press the handle toward a position parallel to the axis of the coil, thus providing the necessary breaking torque at the notched area.

The compressor member 210 of Figures 21 and 22 has a handle 212 formed from a radial extension of the rearward coil 211. In this case the handle is formed into a fish-tail shape, with a semicircular deviation around the extended axial bore of the coil to allow for the presence of the connected wire or cable, the torsional notch 213 being located at the end of the helix, in an axial plane parallel to the handle, and at a point on the terminal coil directly opposite the beginning of the radial extension. Removal of the handle is accomplished by pressure on the handle in the direction indicated by the arrow 214 of Figure 21.

Still a further modification of the compressor member is represented by Figures 14 and 15, which illustrate a compressor member 141 having a pre-stressed spring wire helix 151 within a suporting shell 142. The tip 143 of the enlarged forward coil 144 engages the edge of one of a number of shallow paraxial grooves formed in the interior wall of the tubular shell 142, thus preventing rotation of said forward coil but permitting sliding motion of the helix lengthwise within the shell. The handle member 145 has a portion 146 formed as a tangential extension of the rearward terminal coil 147 of the helix 151 and a lever arm portion 148 at right angles thereto and terminating in a loop 149. The shell 142 is slotted at the rearward end, as indicated at 150, to permit the entry of the tangential portion 146 of the handle 145. The spring wire of the helix 151 is arcuately notched at the point 153, at the end of the helix and in an axial plane parallel to the lever arm 148, as previously described in connection with Figures 5 and 6. The compressor member 141 is asembled by partially inserting the unstressed conical or cylindrical spring-wire helix into the tubular shell 142, then holding the shell while circumferentially rotating the handle 145 through the desired number of revolutions against the contraction of the helix and until the latter is substantially fully expanded within the confines of the shell 142, and then sliding the coil 151 further into the shell, with the handle member 146 entering the terminal slot 150 therein and thereby maintaining the coil in its fully stressed and expanded condition.

The assembly may then be placed in position as a component of a connector, being particularly effective when used in place of the bare compressor member 116 of Figure 11. However it may also be used with connectors similar to those of Figures 7 and 9, as well as for the production of pig-tail or running splices between wires. After all components of the connection or splice are in place, the handle 145 is torsionally snapped off at the notched area and the helix 151 immediately contracts and makes a strong, tight connection. Where the connection is a pig-tail splice and the cover 142 is electrically insulating, an insulating end plug 152 may be included to provide complete electrical insulation of the connection. Such a plug may be inserted either before or after the unit is applied.

It will be seen that many modifications and combinations of the several structures and component-s hereinabove described and illustrated may be derived without departing from the inventive concepts involved. The compression members described in connection with Figures 5, 13, 14, 16, 19, 21 and 23 are thus applicable in place of compression member 26 of Figure 7. These compression members may generally be cylindrical, or conical, or may comprise various combinations of these or other forms. The connector lug 15 of Figure 1, as also the connector lugs of Figures 9 and 11, may be modified to include two or more wire-engaging sections, and may be made with or without rings or other means for attaching to bolts, bus-bars, etc. The terminal lug 91 of the connector lug 90 of Figure 9 may be shaped for application to bars, rods, or other structures of diverse size and shape, or may be replaced by a flexible wire or cable member capable of conforming to any of a variety of shaped articles.

Likewise the materials of construction employed in the manufacture of my novel connectors are subject to wide variation, depending in part on the type of materials to be connected and the conditions under which the connectors and the connections made therewith are to be used. For connections involving copper or aluminum wires used as electrical conductors, I have obtained best results from Zinc-plated spring steel wire compressor members, the same being lightly lubricated with paramn wax containing at least about 5% of zinc stearate. Lubricated bare steel wire is also effective. Phosphor bronze has also given good results and requires no lubrication. Wires cr rods of other than circular cross-section may be used, although the circular cross-section is more readily available, more easily workable, and generally preferred.

Aluminum connector-lugs are particularly effective in the form shown in Figure 11, since the soft metal shank 113 is deformed sufficiently by the spring-wire helix .116 to provide partial threads along which the elix may advance. Copper is also suitable. Harder materials are better employed in connector lugs having pro-formed threaded areas.

Each of my compressor members employing an extension of the spring wire as the detachable handle membet is notched, as hereinbefore described and illustrated, with what I termed a torsional notch. In such a structure, the full diameter and strength of the wire is maintained over substantially the entire cross-sectional area involved in tensional or compressional stresses during tensioning of the helix. At the same time the crosssectional area of the wire is suiiiciently reduced and the surface sufiiciently weakened to provide for easy breakage and removal of the handle when a twisting torque is applied.

As previously noted, my torsional notch extends over slightly more than about one-third of the circumference of the wire and ranges in depth from about 0.002 to about 0.005 inch. A notch having a \/-shaped or U- shaped cross-section and extending over about 160 degrees of arc is preferred. It should be centered on the side of the wire halfway between the lines of maximum tension and compression set up during application of the compressor member. The following table provides ratios of wire diameter, D, and depth of notch, d, which have been found to produce optimum application and removal characteristics with such l60-degree notches when using spring steel or material of equivalent strength and rigidity.

Table I [Optimum relationship of notch depth and wire diameter, in inches.)

Wire diameter .035 .047 .072 .092 and higher. Notch depth .002 .003 .004 .005.

For larger wires or rods, a notch having a depth of .005 inch is adequate for torsional breakage provided a handle or tool is available with which sufficient torque may be applied. For example, the length of the handle member 27 as indicated by reference to Figure 2 should be considerably increased where spring wire substantially heavier than .05 inch in diameter is utilized.

What I claim is as follows:

1. A compressor member suitable for use in wireconnecting and comprising an expandable wire helix terminating in an outwardly extended and readily removable Wire handle member, the wire being lightly torsionally arcuately notched between said helix and said handle at a position endwise of the helix and in a plane passing through the axis of the helix and parallel to the handle; said handle being so arranged that the helix may be expanded by pressure applied on said handle member circumferentially of said helix, and being readily removable by twisting in a plane parallel to an axial plane of the helix to produce a twisting torque in said wire at the notched cross-section.

2. A covered compressor member suitable for use in wire-connecting and comprising an expandable wire helix terminating in an outwardly extended and readily removable wire handle member, and a tubular cover member surrounding said helix; the wire being lightly torsionally arcuately notched between said helix and said handle at a position endwise of the helix and in a plane passing through the axis of the helix and parallel to the handle; said handle passing through an aperture in the wall of said cover member and being so arranged that the helix may be expanded by pressure applied on said handle member circumferentially of said helix,

7 and terminating at the rearward end in an outwardly extended and readily removable wire handle member, the wire being lightly torsionally notched between the rearward terminal coil of said helix and said handle at a position endwise of the helix and in a plane passing groove in the shell,

53 through the axis of the helix the notch being substantially tending over a portion of the equal to about 160 degrees of arc, and said handle being readily removable by twisting in a plane parallel to an axial plane of the helix to produce a twisting torque in said wire at the notched cross-section.

4. A pre-stressed compressor member suitable for use in wire-connecting and consisting essentially of an expanded wire helix within a tubular insulating shell; said shell having at least one internal longitudinal groove and being slotted inwardly from one end; and said helix having an enlarged single forward coil with the end of the wire protruding and slidably fitting within a longitudinal and having a rearward coil terminating in a outwardly extended and readily removable wire handle member lying in substantially the same plane as said rearward coil, the wire being lightly torsionally ar cuately notched between said rearward coil and said handle at a position endwise of the helix and in a plane passing through the axis of the helix and parallel to the handle; said helix being expanded from a normally unstressed condition of lesser diameter to a highly stressed condition at a diameter approaching the inner diameter of the tubular shell, and being held in such expanded form by the restraining forces of the shell member on the forward and rearward coils of said helix; and said handle being readily removable by twisting in a plane parallel to an axial plane of the helix to produce a twisting torque in said wire at the notched cross-section.

5. An insulated compressor member suitable for use in wire-connecting and consisting essentially of a wire helix within a tubular insulating shell; said shell being open at least at the forward end and being provided with external handle means for applying torque thereto in applying said compressor member; said helix having a rearward coil and a forward coil of substantially the same external diameter as the internal diameter of said tubular shell, and having a plurality of smaller coils intermediate the end coils, forming an axial bore having a diameter less than the. effective diameter of the assembly over which the compressor member is designed to be placed; said rearward coil terminating in an end of said wire extending slightly beyond the outline of the coil and adapted to engage with the interior surface of the tubular insulating shell when torque is applied to the latter in applying the compressor member.

6. A tool adapted for the application of a spring-wire helix to a bundle of wires in forming a compression connection, the helix having a minimum internal diameter smaller than the eliective diameter of said bundle, the rearward coil of said helix terminating in and end of said spring-wire extending beyond the outline of said rearward coil; said tool comprising a tubular member, having at least one paraxial internal projection for slidably engaging the end of said rearward coil, and being provided with external handle means for applying torque; said tool being adapted to fit over said helix and to engage the extended end of said rearward coil thereof for positive rotation of the helix in a forward direction with concurrent expansion of diameter of the helix, and then to be slidably rearwardly removed from said helix.

7. in a wire-connector, the combination of a connect ing lug having a cylindrical section and a wire-engaging section axially adjacent thereto, an elastically expansible helix compressor member elastically enclosing at least a portion of said cylindrical section and capable of being advanced by screw action along said cylindrical section and over said wire-engaging section on manual twisting of the helix around the lug, and manually removable means for applying a twisting motion to the helix through the terminal coil thereof in the direction re quired' to expand the helix against the gripping force of and parallel to the handle, uniform in depth and excircumference of the wire the helix on the lug and to cause the helix to advance toward said wire-engaging section; the internal diameter of the helix in relaxed state being slightly less than the effective diameter of said cylindrical section and substantially less than the effective diameter of the combination of said wire-engaging section and a wire to be engaged therewith.

8. In a wire-connector, the combination of a connecting lug and an elastically expansible wire helix compressor member; said connecting lug having (a) a wire-engaging section of a size such that, when increased by combination with a wire to be engaged thereby, the effective diameter of the section and wire combined is substantially greater than the internal diameter of the relaxed compressor member, and (b) a cylindrical section axially adjacent said wire-engaging section and of an effective diameter slightly larger than the internal diameter of the relaxed compression member but smaller than the effective diameter of the combined wire and wire-engaging section; said compressor member having a multiple-turn helix portion and a manually removable torqueapplying handle formed of the outwardly extending wire of an end turn of said helix, said wire being lightly torsionally arcuately notched at the juncture of helix and handle; said wire helix compressor member being mounted around said cylindrical section with the handle at the end opposite said adjacent wire-engaging section, so that application of torque to said handle against the gripping force of said helix on said lug expands the helix and causes the helix to advance along the lug and over the combined wire and wire-engaging section; and said handle being readily removable by twisting in a plane parallel to an axial plane of the helix to produce a twisting torque in said wire at the notched cross-section.

9. In a wire-connector, the combination of: a connecting lug having a tapered wire-engaging section and, at the smaller end of the tapered section, an axially adjacent cylindrical section; and an elastically expansible wire helix compressor member provided at one end with manually removable handle means for imparting a screwing action to said helix along said lug and comprising an extension of the helix wire outwardly from the terminal coil of the helix, said wire being lightly torsionally arcuately notched at the juncture of said extension and said terminal coil to provide for manual removal of said handle by twisting in a plane parallel to an axial plane of the helix to produce a twisting torque in said wire at the notched cross-section; said tapered wire-engaging section being of a size such that it, in combination with a wire to be engaged therewith, provides an effective diam eter greater than that of said cylindrical section; and said compressor member being of a size and elasticity such that it may be screwed along said cylindrical section and over said combination of wire and wire-engaging section by manual application of torque at the trailing end of said helix through said handle means.

10. In a wire-connector, the combination of: a tubular connecting lug longitudinally slit along an end section to provide a wire-engaging section axially adjacent to a cylindrical section, the eifective diameter of said wire-engaging section when containing a wire-end to be engaged therein being greater than the efiective diameter of said cylindrical section; and an elastically expanded wire helix compressor member around said cylindrical section, the wire of said helix being outwardly extended from the terminal coil of said helix at the end opposite said wireengaging section to provide a handle member and being lightly torsionally arcuately notched at the juncture of said handle and said terminal coil to provide for manual removal of said handle; said compressor member being further elastically expansible over said wire-engaging section containing said wire-end by manual application of torque to said handle in a direction to cause said member to advance thereover by an expanding and screwing action, and said handle being readily removable by twisting in a plane parallel to an axial plane of the helix to produce a twisting torque in said wire at the notched cross-section.

References Cited in the file of this patent UNITED STATES PATENTS