US3056851A

US3056851A - Connector

Info

Publication number: US3056851A
Application number: US857099A
Authority: US
Inventors: William J Scott
Original assignee: Ideal Industries Inc
Current assignee: Ideal Industries Inc
Priority date: 1959-12-03
Filing date: 1959-12-03
Publication date: 1962-10-02
Anticipated expiration: 1979-10-02

Description

Oct. 2, 1962 w. J. sco'r'r 3,056,851

CONNECTOR Filed Dec. 3, 1959 IN V EN TOR.

nit tates atent r 3,055,851 CONNECTOR William J. Scott, Sycamore, ill, assignor to ideal industries, Inc., Sycamore, llll., a corporation of Delaware Filed Dec. 3, 1959, Ser. No. $57,099 it Claims. (3. l'7 i-=-8i) This invention is in the field of connectors of the screwon type and is a new and improved insulating cap with a connecting structure, constructed and arranged to be turned or screwed down over the stripped ends of a plurality of electric wires, for example, two or more, either stranded and/ or solid, of the same or different sizes, or otherwise.

A primary object of the invention is a new and improved electrical connector of the screw-on type.

Another object is a connector having a cap of a stifily flexible material constructed so that the stripped ends of the wires being connected will not pierce, penetrate or damage the end of the cap.

Another object is a connector protected against the stripped ends of the wires puncturing the end of the cap but without complicating manufacture or assembly.

Another object is a connector structure with a guide for the stripped ends of the wires to prevent the cap from being damaged or pierced.

Other objects will appear from time to time in the ensuing specification and drawings in which:

FIGURE 1 is a plan view of the connector;

FIGURE 2 is an end view; and

FIGURE 3 is a section along line 33 of FIGURE 2.

In the drawings, the connector has been shown with an insulating cap or cover which has been indicated generally at it) and may include a generally cylindrical body or shell 12 closed at one end by an end wall 14, which is preferably integral with the cap and generally open at the other end at 16, providing what shall be termed a generally open central bore 18. The bore of the cap or coil houses or encloses a wire coil 2t For purposes of illustration, the coil has been shown generally tapered with a large end 22, adjacent the open end of the cap and a small end 24 adjacent the closed end.

I may provide an enlarged or thickened portion 26 in the cap or shell generally at the open end which may be formed with a threaded inner surface or relief surface 28 on the inside, although this is not necessary. The threads may be molded directly into the inside, and the large end 22 of the coil meshes into the groove of the threads. I prefer to make the cap or shell out of nylon, or polyethylene, or any other suitable thermoplastic material which is tough but somewhat resilient and at the same time is a good dielectric and suitable for high temperature use.

The inner surface of the bore may remain somewhat cylindrical from the open end toward the end wall but the intermediate or middle turns of the coil have been shown as decreasing in diameter, or tapered, as at 29, so

that a clearance or spacing is provided at 30 throughout the majority or a substantial portion of the length of the coil with respect to the inner surface of the cap, although this is not necessary. This provides what is referred to as a free spring connector.

An extended and possibly distended turn 32 may be provided adjacent the small end of the coil to serve as a guide or pilot for the small end to center it relative to'the axial bore of the cap. The spacing, shown at 36, is not totally necessary and the coil may have a uniform pitch throughout its length.

The end at of the coil may be extended slightly or pulled away from the normal turns of the coil and an abutment 38 may be provided in or as an integral part Patented Oct. 2, 1962 of the shell or cap to function as a shoulder or anchor for the end of the coil. This abutment or shoulder may be of a suitable formation but it is preferred that it oppose the end of the coil to resist the normal rotative tendency of the coil, when the connector is being turned down over the stripped ends of a plurality of wires. The abutment may be a separate metal insert, but I find it easier to mold it as an integral part. The end 34 of the coil might be blunt, turned in or back, or otherwise suitably shaped, to engage the abutment regardless of its particular size, shape or disposition.

The open end of the cap may be provided with an enlarged, preferably integral skirt 40, which may be cylindrical and well rounded, as at 42, where it joins the shell or cap to function as a guide or funnel and also as a skirt to prevent arcing to a ground.

The end wall of the cap at the closed end of the bore is offset, as at 44, and moves into a tapered socket or cavity 36 behind the abutment 38. The depth of the socket 46 or cavity may varysomewhat and I position a steel or metal ball or sphere 48 in the form of an insert next to or in the socket which, as shown, has an outside diameter slightly greater than the inside diameter of the throat 5d of the coil to prevent the ball orsphere from coming out. As shown in FIGURE 3, the ball may fit loosely within the large or expanded turn 32 of the coil which pilots or centers the coil in the rear end of the cap.

The socket has a tapered inner wall 52 which is closed off by a rear wall 54 which has a diameter less than the ball diameter 48. Since the socket is tapered, it enlarges forwardly and the inside diameter of the socket at its entrance, say at the beginning of ofiset 44, is on the order of and possibly slightly greater than the ball diameter. Or it might be slightly less. But, in any event, the material is sufficiently distortable or flexible so that when the ball is pushed toward the socket, the sides will flex out somewhat at the socket entrance, and the ball may be forced in. The object of this is that when the stripped ends of the wires move through the throat 50 and contact the ball, the pressure developed will force the ball into the tapered socket where it will seat firmly. Thereafter, if the connector is backed off of the wires, the ball will stay in the socket.

This has the advantage that a connector of this type in use expands the throat 50 of thecoil. The throat may taken an enlarged set and could open up sufiiciently so that the ball would otherwise fall out. But this can only occur after the connector has been used at least once and possibly more. And when the connector has been used the ball will have been forced into the socket and will stay in place.

The use, operation and function of the invention are as follows:

therein in a suitable manner. The cap and coil, as a unit,

are then screwed down on the stripped ends of a plurality of electric Wires in a known manner. The coil functions like threads so that the cap and coil automatically feed down on the stripped ends of the wires and will compress the wires together and form grooves or threads thereon corresponding to the coil. The coil is interlocked to the cap so that when the cap is rotated, the coil will also be rotated.

When the coil is screwed down on the Wires, the stripped ends will eventually pass completely through the coil and will engage the end wall of the cap. The ends of the wires have normally been cut or snipped with electricians pliers or the like and are sharp or jagged. When the stripped ends contact the end wall of the cap, if the cap is thereafter turned an appreciable amount, the sharp ends of the wires may rip or drill through or otherwise mar the end wall which is plastic.

To prevent this, I position a ball insert or sphere or spherical object in the cavity or socket between the end of the coil and the end wall of the cap which functions as a deflector or guide, as well as a shield, for the end wall. This is to say that in addition to preventing direct contact between the sharp ends of the wires and the end wall, the

spherical object will deflect or guide the stripped ends in an outward direction and at the same time will bend the ends of the wires into a helical or circumferential direction so that even if the stripped ends were extended and could get past the sphere, they would not contact the end wall. At the same time, the stripped ends will pass between the throat of the coil and the forward convex face of the sphere and will become tightly interlocked resisting withdrawal.

In a connector of the particular type shown, the throat of the coil will expand when the stripped ends of the wires are inserted and in all probability will eventually come to an inside diameter which is greater than the outside diameter of the sphere. But this is of no consequence since the presence of the wires will prevent the sphere from coming out.

The use of a ball has the advantage that, in assembly, it does not have to be oriented. The ball can be merely dropped within the cap and then the spring may be in serted and turned into place until it is fully seated. The ball in no way interferes with the drive or interlock between the cap and coil since the abutment 38 is radially outside of the circumference of the ball. The ball may be totally free in the socket between the inner end of the coil and the end wall of the cap. But since its diameter is greater than that of the throat of the coil, it cannot get out. The ball has the additional advantage that it will rotate when contacted by the stripped ends of the wires and will provide a distributed area of contact under the thrust of the stripped ends, thereby spreading the load and preventing a failure. The ball does not have to be truly spherical but I want it to be self-orienting.

The ball may be simply dropped into the cap during manufacture and then the coil is screwed in and assembly is complete. In this condition the ball will be loose. But once the connector has been used the ball will be forced into the tapered socket and will thereafter stay in place.

It should be noted that the spacing is such that when loose, the ball is sufficiently behind the last turns of the spring, as at 24 and 50, so that a certain amount of cavity behind the throat 50 is available to accept the stripped ends of the wires when they come through the throat. In effect, I provide a certain amount of cavity behind the spring to allow for some misalignment of the wires. This also allows the connector to hold on to the minimum combinations. The ball is free prior to use of the connector and will actually rattle around a bit. But when the connector is turned upright with the bore up and the ball resting on the inlet of the tapered socket, there will be sufficient spacing between the top of the ball and the throat 70 such that the stripped ends of the wires can work their way in during assembly.

Since the ball is round, it deflects the wires on an angle other than what the connectors would ordinarily take. In fact, the wires actually bend around and become interlocked behind the coil. 7

While I have shown and described the preferred form and suggested several variations of my invention, it should be understood that several additional modifications, substitutions, alterations and changes may be made without departing from the inventions fundamental theme. The cross section of the wire may be round, square, or otherwise. I mentioned nylon as the material of the cap but it might be any other suitable material. With these and other modifications in mind, I wish that the invention be unrestricted, except as by the appended claims.

I claim: a

1. In an article of manufacture, a connector for joining the stripped ends of two or more electric wires and the like, including a cap of a stifiiy flexible plastic material capable of being penetrated by the wire ends with a generally central bore open at one end and closed by an end Wall at the other end, a generally cylindrical wire coil in the bore, an insert having the general shape of a sphere positioned between the inner end of the coil and the end wall of the cap and having a diameter greater than the inside diameter of at least a part of the coil, and means for holding the coil in the bore.

2. The structure of claim 1 further characterized in that the sphere is confined between the end wall of the cap and the inner end of the coil, and is otherwise free for movement.

3. The structure of claim 1 further characterized in that the inner end of the coil is provided with an enlarged turn and with a reduced turn forwardly thereof toward the open end of the cap to define a partial socket opposite and spaced somewhat from the sphere.

4. The structure of claim 1 further characterized in that the sphere has an outside diameter which, while greater than the inside diameter of at least a part of the coil, is less than the inside diameter of the bore.

5. The structure of claim 1 further characterized in that the end wall of the cap is formed into a socket inside the cap accepting the sphere.

6. The structure of claim 1 further characterized in that the end wall of the cap is formed into an inner tapered socket, the entrance to the socket opening into the bore of the cap and having an initial diameter on the order of the diameter of a sphere such that when the connector is screwed down on the stripped ends of a plurality of electric wires and the wires contact the sphere and push it into the socket, the sphere will become lodged in the socket in a tapered press fit.

7. In an article of manufacture, a connector for joining the stripped ends of two or more electric wires and the like, including a cap of a stifily flexible plastic capable of being penetrated by the wire ends with a generally central bore open at one end and closed at the other end by an end wall, a generally cylindrical wire coil in the bore, an insert positioned freely between the inner end of the coil and the end wall and having a circular exterior with an outside dimension greater than the inside dimension of at least a part of the coil, and means for holding the coil in the bore.

8. In an article of manufacture, a connector for joining the stripped ends of two or more electric wires and the like, including a cap of a stifily flexible plastic capable of being penetrated by the Wire ends with a generally central bore open at one end and closed at the other end by an end wall, a generally cylindrical wire coil in the bore, the end wall of the cap being formed into an inner socket, one end of the socket opening in the bore of the cap, and an insert positioned freely between the inner end of the coil and the socket in the cap and having an outside dimension slightly greater than at least a portion of the diameter of the socket such that when the connector is screwed down on the stripped ends of a plurality of electric Wires and the Wires contact the insert and force it toward the socket, the insert will become lodged in the socket in a press fit.

9. In an article of manufacture, a connector for joining the stripped ends of two or more electric wires and the like, including a cap of a stiffly flexible material otherwise capable of being penetrated by the wire ends with a generally central bore open at one end and closed by an end Wall at the other end, a generally cylindrical wire coil in the bore, means for holding the coil in the bore, and a deflector in the bore at the end wall for preventing the wire ends from penetrating the end wall having an outside dimension appreciably less than the inside dimension of the bore at the end wall.

5 6 10. The structure of claim 9 in which the deflector is 2,199,532 Weeks May 7, 1940 in the form of an insert formed separartely from mhe cap 2,308,286 Joyce Jan. 12, 1943 and coil. 2,890,266 Bollmeier June 9, 1959 3,001,002 Schinske "0-- Sept. 19, 196 1 References Cited in the file of this patent 5 FOREIGN PATENTS UNITED STATES PATENTS 2,110,45 Applegate 3, 19-33 2721928 Switzerland P 1951