US2554387A

US2554387A - Wire grip

Info

Publication number: US2554387A
Application number: US121717A
Authority: US
Inventors: James J Saul
Original assignee: Reliable Electric Co
Current assignee: Reliable Electric Co
Priority date: 1949-10-17
Filing date: 1949-10-17
Publication date: 1951-05-22
Anticipated expiration: 1968-05-22

Description

May 22, 1951 J. J. SAU.. y 2,554,387

WIRE GRIP Filed OGb. 17, 1949 Patented May 22, 1951 WIRE GRIP James J. Saul, Chicago, lll., assignor to Reliable Electric Company, Chicago, Ill., a corporation of Illinois Application October 17, 1949, Serial No. 121,717

3 Claims.

This invention relates to a wire grip of the type wherein wire gripping jaws cooperate with a tapering tubular shell to produce wire gripping action. The invention resides in the provision of means whereby the jaws are in a free or unbiased condition until such time as the end of the wire to be gripped passes completely through the jaws, thereby assuring gripping action throughout the entire length of the jaws.

The usual wire grip of this type has a resilient element such as a spiral spring that applies a continuous bias to the jaws. In other words, the spring continuously urges the jaws toward the small end of the tapering shell. When a wire or conductor is inserted in a grip of this kind, the end of the wire pushes the jaws against the spring and moves the jaws to a shell region of greater diameter. This permits radial ,expansion of the jaws so that the wire end may be pushed into and, in fact, completely through the jaws. Thereafter, the spring urges the jaws in the opposite direction to produce an initial gripping action between the jaws and the wire.' As the wire is normally under tension, the stress in the wire itself further moves the jaws into the shell taper, thereby increasing the gripping force to a sucient amount.

While in most cases a grip of this type functions in a satisfactory manner, experience has shown that difficulties resulting in faulty connections sometimes occur. Many wires used are of the stranded type, and occasionally a strand at the wire end becomes out of lay when the wire is inserted in the grip. Such an out of lay strand may enter the space between adjacent jaws with the result that proper relationship between the jaws and the wire is never established. A connection whereinvan out of lay strand. is disposed between adjacent jaws will withstand some tension, but it will ordinarily fail when subjected to normal and sometimes variable tension.

A more or less similar dii'iculty occasionally arises when solid wires are used. The cut end of such a wire may have a burr, a departure from proper wire shape. If the wire is inserted only part way through the jaws, the burr surface may engage one or more of the jaws. In this case, gripping occurs over a reduced area, and proper gripping relationship between the jaws and the wire is not established.

Accordingly, it is desirable to provide an arrangement whereby the jaws do not initially grip the wire until it is certain that the wire end has passed completely through, and perhaps beyond,

the gripping jaws. One object of the invention is to provide such an arrangement.

Another object is to provide a wire grip having a trigger element that initially holds the jaw biasing spring out of engagement with the jaws. The trigger element is actuated by engagement thereof by theend of an inserted wire. This engagement occurs only after the wire end has passed completely through and beyond the wire grippingv jaws.

Qther objects and advantages of the invention will be apparent as the description proceeds, reference being had to the accompanying drawing wherein one form of the invention is shown. It is to be understood that the description and drawing are illustrative only, and are not to be taken as limiting the invention except insofar as it is limited by the claims.

In the drawing:

Fig. 1 is a side view, partly in section, showing my improved wire grip embodied in a wire splice with the grip shown in engagement with a wire;

Fig. 2 is a sectional view showing the wire grip prior to nal engagement with a wire;

Fig. 3 is a sectional view on line 3 3 of Fig. l, and Fig. 4 is a sectional view on line 4-4 of Fig. 1. f

Referring to the drawing, my improved wire grip is illustrated as embodied in a line splice of the general type shown in U. S. Patent No. 2,138,913 to W. G. Fotsch. The grip, however, may equally well be used in other devices such as deadend connectors and the like.

The wire splice illustrated is symmetrical, so only a single half portion will be described in detail.

The left hand half of the splice comprises `a wire grip having a tubular shell 1. The left end oi?k shell 'I is tapered interiorly throughout a portion VIl, while adjacent shell portion 9 is generally non-tapering.

A plurality of gripping jaws I0, three jaws in the example shown, are contained within tapered portion 8. Jaws I0 are interconnected by means of an annular member I2 in such a manner that the jaws may oat radially of shell 'I and at the saine time may maintain a uniform circumferential spacing. Annular member I2 also insures uniform longitudinal motion ofv the jaws.

Jaws I0 and annular connecting member I2 may be of the type described in detail in U. S. Patent No. 2.2381138 to L. Jugle. Regardless of the particular structure used in the jaws and jaw connecting member, it is necessary that the latter be provided with an aperture of suflicient A trigger element 20 is located within the shell between jaws I0 and stop member I5. Trigger element 20 is a sleeve of spring metal material having a plurality of longitudinal Slots 2| (Figi. 2) extending inwardly from the end adjacent stop member I5. Sleeve portions 22 between the slots 2| are inclined toward the sleeve axis, the free ends of such portions being bent to form inwardly facing hooks 23.- These hooks arerv adapted to engage flange I'I of stop member I5 as `shown in Fig. 2.

The other end of spring 26 is seated against stop member I5.

The Various parts of the wire grip prior to connection to a wire are in the respective positions shown in Figp2. The hooks 23 of inclined sleeve portions 22 engage flange II of the stop member. Spring 2B is Vcompressed to a relatively high degree. Jaws I0 are normally disposed within taper portion 8, although they are free to move from an extreme position within the taper to the trigger element 20.

A wire 30, which may be of the stranded type as shown, is inserted into the tapered end of the shell. The wire pushes the jaws back as yfar as is necessary to expand them to permit wire passage. Since spring 26 is initially out of engagement with jaws I0, there is no bias on the jaws at 'this time. As shown in Fig. 2, the wire end, after passing through the jaws, enters trigger element 20. Continued inward positioning of the wire causes the wire end to engage the conical surface defined by the -inclined sleeve portions of the trigger element, thereby Iradially expandling the portions so that hooks 23 become disengaged from flange Il. This disengagement releases trigger element 20 so that spring 26 with a more or less snap action moves the element into engagement with jaws I0. The spring further functions to urge jaws I0 into the tapering end of the shell to eiect an initial gripping relation between the jaws and wire 30. Thereafter, the wire is properly sagged in, and that plus the normally present tension on wire .30 in- :creases the gripping action to an amount sufcient to provide a rm connection.

This arrangement insures that no gripping action will occur before the wire end has passed completely through the jaws. Since out of lay strands usually occur, if at all, at the wire end, it will be seen that such a strand cannot result in an improper connection with my improved grip. The same is true with respect to a burred end on a solid wire. Since the jaws engage the conductor throughout their length,- a connection of maximum resistance to separation is insured.

From the above description it is thought that the construction and advantages of my invention4 will be readily apparent to those skilled in the art. Various changes and modifications may be made without departing from the spirit or losfing the advantages of the invention.

Having thus described my invention, what I claim as new and desire to secure by Letters Patv ent is:

1. A wire grip comprising a tubular shell tapering interiorly toward one end, wire gripping jaws vwithin said shell, a stop member at the other "shell end, said .stop member having a flanged stud facing said jaws, a trigger element between said V`jaws, and said stop member, said trigger element comprising a sleeve of spring metal having a plurality of longitudinal slots extending inwardly from the end adjacent said stop member and an annular ange on .the other end, the sleeve porftions between said slots being inclined toward the sleeve axis with the portion ends being bent to form inwardly facing hooks adapted to engage lsaid anged stud, and a compressed spiral spring 'between said .stop member and said kannular flange whereby after release of said hooks from said flanged stud upon expansion of said sleeve portions by an inserted wire, the spring pressed trigger element forces said jaws into the tapering shell end in gripping relation with the wire.

2. A wire grip comprising a tubular shell tapering interiorly toward one end, wire gripping jaws within said shell, a stop member at the other shell end, a trigger element between said Yjaws andsaid stop member, said trigger element comprising a sleeve .of spring metal having Va plurality of longitudinal slots extending inwardly from the end adjacent said stop member and Van annular flange on the other end, the sleeve Vportions between said slots being inclined toward the sleeve axis with the portion ends being bent to form inwardly facing hooks adapted to engage said stop member', and a. compressed spiral spring between said stop member and said annular flange whereby after release of said hooks 'from said stop membel` upon expansion of said sleeve portions by an inserted wire, Athe spring pressed trigger element forces said jaws into the tapering shell end in gripping relation with the wire.

3. A wire splice comprising a pair of wire grips as dened in claim 2, the stop members of the two grips comprising a threaded plug to which the tubular shells are attached in end to end relation.

JAMES J. SAUL.

REFERENCES CITED The following references are of record in the Vrlle of this patent:

UNITED STATES PATENTS Number Name Date 296,169 Hill et al. Apr. 1, 1884 1,854,783 Cook Apr. 19, 1932 2,314,579 Frank Mar. 23, 1943