US2931008A

US2931008A - Electrically insulating devices

Info

Publication number: US2931008A
Application number: US639325A
Authority: US
Inventors: Abrams Ralph
Original assignee: Cambridge Thermionic Corp
Current assignee: Cambridge Thermionic Corp
Priority date: 1957-02-11
Filing date: 1957-02-11
Publication date: 1960-03-29
Anticipated expiration: 1977-03-29

Description

*si-TM March 29, 1960 R. ABRAMS ELECTRICALLY INSULATING DEVICES Filed Feb. 1l, 1957 United States Patent 2,931,008 a Patented Mar.y 29 19:60

4 Claims. (Cl. 339-213) This invention relates to composite insulators for use in` electrical installations, generally speaking of the lead through and connector types which can be mounted in apertures of supports such as panels or chassis and which are capable of receiving therewithin conducting means such as soldering lugs or jacks.

The principal object of the invention is to provide devices of the above character which are especially suited for the incorporation therein of superior electrically insulating materials of the types exemplified by polyfluoroethylene polymers which have little elastic tendency or memory to` return to an original shape after having been more or less suddenly deformed, or at least a tendency to become permanently deformed under continuous stress, but which on the other hand have a comparatively high tendency to gradual fiow due to low internal molecular friction. Such materials are ill suited for incorporation inconventionally designed and fabricated devices of the above type and it was found toV be quite important to find techniques for providing, in a commercially acceptable Way, assemblies which permit the safe use of such insulating materials, taking advantage of the above-mentioned electrical characteristics thereof.

Other objects are to provide improved insulating assemblies which can be manufactured with a minimum amount of molding, machining and assembling operations, to provide lead through insulators which incorporate insulating material of the above type without danger of losing their shape and which lend themselves for assembly with metal parts according to mass production techniques, to provide jack assemblies which make tight and positive connection, firmly engaging plugs for a long time without danger of loosening, with practically no contact resistance and at the same time easily removable, to porvide such devices which can be easily assembled or mounted on panels of widelyrvarying types, and to providek insulated assemblies of this type which lend themselves especially well to miniaturizing.

A brief summary indicating the nature and substance of the inventiomfor attainingthe above objects, charac- `terizes its principal aspects as follows.

Composite articles such as insulating mounts to which the invention is applied comprise an essentially cylindrical insulator body of material having the above-mentioned properties characteristic of polyfluoroethylenes such as appreciable tendency to flow due to low internal friction` and little tendency to return elastically to an original shape, this insulator body having an axial cavity and two transverse deformation faces one being preferably at an end of the insulator body and the other extending at an intermediate region; a metal insert with connecting means and a core that fits the cavity of the v insulator body and has a polygonal such as knurled or hexagonal portion; a metal mounting shell fitting around the insulator body; and on the pin and the shell insulator confining faces which contact, upon assembly, respective ones of the deformation faces ofthe insulator body such that the insulator material is forced to fill the space between pin andV shell and to bulge outwardly into the open space between the now contacting, confining and deformation faces. In this manner the insulator is on the one hand sufficiently deformed for permanently firm attachment by confinement between the faces, the pin core and, the shell, and on the other h and sufficiently restrained to prevent any flowing from such confinement. The polygonal portion of the insert pin becomes firmly lodged between` the faces and prevents rotational displacement.

In an important practical embodiment, the deformation faces are constituted by the two outer transverse surfaces of an axially recessed cylindrical head of the insulator body, and the confining faces are constituted by the inner transverse face of an axial end recess of the shelland byy a transverse face of a collar of the insert pin which yalso has a polygonal collar portion embedded between the faces to prevent rotational as well as axial displacement of the three components, with the aid of the bulge of the insulating body.

Inanother important practical embodiment, the deformation faces. are constituted by inner and outer transverse surfaces of an axially recessed cylindrical head of` ly prevented bythe confining faces and the bulge of the insulating body.

In an additional aspect, the invention is incorporated in a jack assembly with an insert having at one end jaws that are yieldingly forced together by a spring ring and having at the other end a lug or other conductor connecting means, with the, jaws confined within an open cavity portion of the insulator body and the shell, and with the lug protruding from the latter, the jaws and the lug being separated by a collar of the insert which provides on one side a confining face and forms on the other side the bottom of the open cavity portion for the jaws.

These and other objects and aspects of the invention will appear from the following description of two typical embodiments thereof illustrating its novel characteristics. This descripition refers to a drawing in which Fig. 1 a top view of a feed through insulatorr according to the invention;

Fig. 2 is a side elevation partly in section'on lines of Fig. 1, of the fully assembled feed through insuator;

Fig. 3` is a section on lines 2--12 of Fig. l of the components of the insulator during assembly prior to the final; securing and with the parts in preformed shape as yet not deformed by the assembling operation;

Fig. 4 is a top view of an insulated panel bushing jack according to the invention;

Fig. 5; is al side elevation partly in section on lines 5-5 of Fig. 4 of the fully assembled jack; and I Fig. 6 `is a section on lines 5'-5 of Fig. 4 of the components of the jack during assembly but prior to the final joining and with the parts in preformed shape as yet not deformed by the assembling operation. I

Fig. 3 shows the components of an assembly according to Figs. l and 2 in their preformed shape prior to` flanges 1,1.1 oran annular recess 11.2.', for soldering conductors'thereto. Itv will be understood that other r12 of the insert. The deformation faces of the insulator body are indicated at 26.1 and 26.2. The insulator body 2.1 is made of synthetic material of thepeculiar type for which, as mentioned above, the herein described construction-isespecially suited. This material comprises certain compounds of the polyethylene and especially of the polyfiuoroethylene type which have particularly favorable electrical and mechanical properties, such as polyethylene, polychlorotriuoroethylene and polytetrafluoroethylene resins commercially available under the trade names Alathon, `Teflon and Kel-F respectively. These be used instead of.`

materials exhibit peculiar properties which make them i unsuitable for conventional assembly with metal components. They are non-adhesive, inelastic in the sense that they have a poor memory of previous yshape and that they are of comparatively low viscosity in the sense that they have little internal friction so that they are easily deformable and have a tendency to flow around obstructing surfaces. The present invention utilizes the easy ow characteristics of such materials and also their low tendency elastically to return after deformation of an original shape for purposes of the pressurable assembly technique to be described below, by avoiding possibly detrimental effects of gradual flow.

The shell component 31 has a sleeve portion 32 with an outside thread 32.1, a sleeve head and flange portion 33 and, annularly extending therefrom a staking rim 35. The confining face of the head 33 is indicated at 36.1.

For assembling this feed through insulator, the three components are inserted into each other as indicated in Fig. 3. wardly towards and somewhat intothe head portion 23 of the insulator body 21, with the result lindicated in Fig. 2, namely with the insulating material being forced into the space between the confining faces 16.1 and 36.1

of the insert and the shell, respectively.l Thus, the insulating material of the above described character is deformed to assume the shape of the space between these confining faces 16.1 and 36.1 which after assembly convtact the deformation faces 26.1 and 26.2 of the insulator body which is forced to bulge outwardly at 26 (Fig. 2) into the opening between the confining faces of insert and shell. During the deformation of the insulator body it is also forced to flow around the hexagonal collar 16 which becomes thus embedded in the insulating material between the now contacting confining and deformation faces, as clearly shown in Fig. 2. The'polyg'onal collar prevents rotatory as well as axial loosening of the assembly. After assembly, the inner surface of the curved-in lip of the rim 35 and the contacting insulator surface also constitute confining and deformation faces, respectively. In this manner the insulating material is sufficiently deformed to become permanently and firmly attached to the two

metal parts

11 and 31 by confinement between the face 16.1 of the insert pin and the face 36.1 of the shell, but it is also sufficiently prevented from flowing from such confinement.

This assembly can be mounted in any convenient manner, for example by inserting it into a hole of a panel p such as indicated in Fig. 2 and -by fastening it therethrough with a nut or other fastening means. Conductors i can be joined to one or both lugs by soldering or any other means serving the purpose at hand; the solder lug collars or recesses 11.1, 11.2 can be omitted or replaced by appropriate joining means.

The jack assembly according to Figs. 4, 5, and 6 comprises, analogously to the previously described embodi- 76 Thereupon the rim 35 is pressurably forced inaoanoos ment, a pin or insert 61, an insulator body 71, and a shell 81.

The insert portion 61 has on its core portion a cylindrical collar 62 and on one side of this collar a jack device 63 with four jack fingers 63.1 to 63.4 (Fig. 4) which surround a cylindrical bore 63.5 for receiving a conventional plug contact (not shown) and have annular recesses 63.11 containing a spring ring 64 that forces the ngers 63.1 to 63.4 towards each other, thus frictionally confining the plug upon its insertion into bore 63.5.

`At the other side ofthe collar 62 is a solder lug 61.8

or other device suitable for connecting a conductor to the jack core and a somewhat wider shank portion 61.4 with a polygonal, here knurled part 61.5 thatfits the bore of the insulator body. Between portions 61.4 and 61.8 is an undercut shoulder 61.6, for the purpose to be explained below.

The insulator body 71 has a head portion 72, a sleeve lportion 72.1 and a flange portion 72.2. The head portion has an axial bore that fits Vthe core portion 61.5 of the insert, and the sleeveand flange portions have a wider cavity 72.5 which accommodates the jack whose collar 62 forms the bottom.

The shell portion 81 has a flange portion 81.2, a

conning sleeve portion 81.3 and, by way of example in this embodiment, an undercut shoulder 81.6 for fasten- 'ing to a support.

` This embodiment further requires an annular insulator confining means Such as a washer 91 whose hole 91.1

fits over the shank portion 61.4 of the core.

lIn this embodiment, the deformation faces appear at y71.1 and 71.2 of the insulating body 71, and the con- 'fining faces at 61.1 of the collar 62 of the insert and at 61.2 of the washer 91.

For assembling the jack device according to Figs. 4

Ato 6, the insulator and shell portions are firmly held at the jack end in a suitable support, and the washer 91 is pressed against the head portion 72 of the insulator whereupon the undercut shoulder 61.6 is staked or turned over to retain the washer in this position constituting a -thrust receiving portion of the insert 61, as clearly shown in Fig. 5. Again, as described above With reference to Fig. v2, the insulator body is pressurably retained with its deformation faces 71.1 and 71.2 of the insulator body v71 between the confining faces 61.1 and 61.2 of the 'insert pin 61 and the washer 91, respectively; the insulat- -ing material bulges out as shown at 76 of Fig. 5. The

knurled portion 61.5 prevents relative rotation, while axial loosening is mainly prevented by the confining faces. The insulator and shell portions which come into contact at 76.1 of the bulge also act to some extent as confining .and deformation faces. .Y f

. As indicated in Fig. 5,` this jack assembly can be mounted on a panel p by staking the undercut shoulder 81.6 over the panel.

While it is difiicult to forma fully satisfactory theoretical explanation of the behavior of the Vabove characterized polymers in assemblies of this type, it appears that nency can be reasonably expected.

It should be understood that the present disclosure is for the purpose of illustration only and that this invention includes all modifications and equivalents which fall 'within the scope of the appended claims.

I claim:v g l. A ,composite article suchk as an insulating mount,

rsf-JA.

comprising: an insulator body of material having physical properties characteristic of polyfluoroethylenes such as appreciable tendency to flow due to low internal friction and little tendency elastically to return after deformation to an original shape, said insulator body having a cylindrical cavity and two transverse deformation faces one at an end of the insulator body and the other extending at an intermediate region thereof; a metal insert having at one end connecting means, a core that fits said cavity of said insulator body, a transverse insulator confining face between said core and said connecting means, and at the other end a deformed thrust receiving portion; a metal mounting shell fitting around said insulator body at the region of said confining face of the insert short of said thrust receiving portion of the insert; and annular confining means between said insulator body and said thrust portion, said confining means being applied under pressure to contact said deformation faces of the insulator body with said confining face of the insert and with said annular confining means; such that said insulating material is forced to fill the space between the insert and the shell and to bulge outwardly into the open space between said confining means and said shell; whereby rthe insulator body is on the one hand sufficiently deformed to provide permanently firm attachment to the insert and the shell by confinement between the confining face, the confining means, the insert core, and the shell, and is on the other hand sufiiciently restrained to prevent flowing from such confinement.

2. A composite article such as an insulating mount having a central conductor surrounded by a insulator both of which are confined within a mounting member, comprising: an essentially cylindrical insulator body of material having physical properties characteristic of polyfiuoroethylenes such as appreciable tendency to fiow due to low internal friction and little tendency elastically to return after deformation to an original shape, said insulator body having an axial cavity and two transverse deformation faces one being an end face and the other being an internal face extending from said cavity therewithin; a metal insert means fitting into said cavity; a metal shell means fitting unconstrictedly cylindrical around said insulator body; and on said insert means two essentially transverse insulator body confining faces which contact with axial pressure respective ones of said end and internal faces of said insulator body with said shell means extending partly into the region between said deformation faces and said confining faces such that said insulator body is forced outwardly into the free opening between said confining faces and said shell means; whereby said insulator body is sufiiciently deformed for permanently firm attachment by confinement between the faces and the insert and shell means, and also sufficiently restrained to prevent liowing from such confinement.

3. Article according to claim l, wherein said transverse insulator confining face of the metal insert is constituted by a collar, rwherein said thrust receiving portion of the insert is constituted by a staked undercut shoulder, and wherein said annular confining means s constituted by a washer between said insulator body and said staked shoulder.

4l Article according to claim 2, wherein said metal insert means is of polygonal cross section in a region between said insulator body confining faces.

References Cited in the file of this patent UNITED STATES PATENTS 2,700,144 Flanagan Ian. 18, 1955 2,726,280 Demurjian n Dec. 6, 1955 2,785,219 Rudner Mar. 12, 1957