US2854648A - Electrical connector - Google Patents

Description

Sept. 30, 1958 ER Y 2,854,648

ELECTRICAL CONNECTOR Filed March 11, 1957 /d /5 INVEN'M l(. 0316 772 2 '77 a r rok/vz/ f United States Patent ELECTRICAL CGNNECTOR Quentin Berg, New Cumberland, Pa.

Application March 11, 1957, Serial 1510-6455249.

7 Claims. (Cl. 339276) This invention relates to electrical; connectors andhas particular reference to certain new. anduseful improvements for securing a connector'to the end of a wire.

It is a common practice to crimp a. ferrule of an electrical connector around the end of a wire for connecting the connector to the wire, and in some cases the: inside surface of the ferrule is provided; with a series of fine parallel grooves or the like extending-transversely of the wire so as to form wire gripping edges or ridgeswith the object of improving the grip between the wire and the ferrule. Such grooves have the disadvantage of necking the wire and often sever some of the strands of a stranded wire if such is used, and in addition have failed to achieve the purpose for which they are. used, namely the obtaining of uniformly good. quality electrical and mechanical connections between the'wire' and the ferrule.

The construction herein disclosed overcomes the foregoing difliculties and in addition to providing a uniformly good grip and connection between. the wire and theferrule provides certain unexpected and important advantages.

I have found that by forming or bending the metal stock which defines the ferrule so as toprovide metal stiffening corrugations or convolutions in the stock which extend transversely of the wire and with thecorrugations on one side of the ferrule offset from thoseon the other side of the ferrule, when the ferrule is crimped onto the end of the wire the offset corrugations on" the opposite sides of the ferrule will corrugate the wire without necking and will positively interlock the wire and the ferrule. Since the corrugations employed are of such. a character as to stifien the metal, it ispossible to use thinner metal stock without sacrifice to the security or electrical conductivity of the joint. In addition, the give or yieldability. created in the ferrule by the corrugations substan-' tially reduces the criticality of. the crimp height inthe applicator because the give of the corrugated metal stock compensates for excess travel of the crimping die. The yieldability imparted to the metal stock by the corrugations also makes it possible to use a given size ferrule for a large range of wire sizes, thereby eliminating substantial die costs and the expense of setting up-different sized dies in the same machine when different sized wires are to have connectors applied thereto.

A principal object of the invention therefore is to provide a new and improved ferrule for securing a connector to the end of a wire.

Other and further objects of the. invention will be apparent from the following description and claims and may be understood by reference. to the accompanying drawings, of which there is one. sheet, which by way of illustration show a preferred embodiment of the. invention and what I now consider to be the bestmode in which I have contemplated applying the principles of my invention.

Other embodiments of the invention may beusedtwithout.

departing from the scope of the present inventionas set forth in the appended claims.

In the drawings:

2,854,648 Patented Sept. 30, 1958 Fig. 1 is a plan view of a partially formed-connector embodying the invention;

Fig 2 isaplan view of the connector ready to have a wire; connected thereto;

Fig. 3 is a plan view of a connector with the wireconnected thereto Fig. 4 is a longitudinal sectional view taken alongthe: line --4 of Fig. 3'

Figs. 5, 6 and 7 are.sectional-views-.-through the crimping dies. of. an applicator,- and: the ferrule. of.- the; connector and illustratingrthemannerin which the'ferrule. is crimped; onto the wire; and;

Fig. 8 is an enlargedsectional view through a ferrule: as crimped around a; stranded: wire but-.with some of the: wire strands.- omitted;

The connectorelement: Ill-may be. formed from flat; brass or other suitable metal; stock, and; as; illustrated: is; a; disconnect type; of: connector providing. a. socket 12; The.

opposite. sides of. the. channel 16 are. provided: with integral upstanding'flanges- 18- which together with the bottom of the. channel form the ferrule. 14 when the flanges 18. are; crimped. around a wire. as illustrated in Figs. 3; 4 and 8.

The metal stock forming thebottom of the channel 16 and the flanges 18 is formed to provide metal stiffening corrugations or-convol'utionsZtl transversely of the chan nel 16. For .017 inch metal stockI have found that a corrugation depth of DOE-.008 inch provides excellent results; In any event, the corrugations should be of suihcientdepth to corrugatethe-wire when the ferrule is. crimped on the wire. The corrugations or convolutions employed are folds in the metal stock which serve to substantially increase the stiffness ofthe stock while at the same time creating a certain give or yieldability in the corrugated stock which flat stock does not have. The corrugations I- employ are not tobe confused withthefine grooves or ridges heretofore-formed ontheinner surfaces of ferrules made from flat as distinguished from corrugated stock and which grooves or ridges function merely as wire biting edges. The corrugations 20 in the flanges 18 are aligned with'each' other but are oflset from the corrugations in the bottom of 'the channel 16.

The connectors 10 are made in strip form'and are fed into an applicator which crimps the ferrule 14 around the wire to which it is to be connected. The wire may be either a stranded wire or a solid wire. In'assembling the wire to the ferrule the exposed end of a wire is seated in the channel 16, after which the flanges 18'are crimped over the wire seated in the channel.

Figs. 5, 6 and 7 show the anvil=24 and crimping die 26 of an applicator and the cooperation therebetween. in crimping the ferrule to thewire 22. As illustrated in Fig. 5; the free ends of the flanges 18 are crimped over and contact the wire which is seated in the channel; the ends of the flanges 18" contactinga centering projection 28 in the crimping die 26'. As the press closes. the'flanges 18 are folded over the wire 22 and then the ferrule is squeezed about the who so as toflatten the ferrule,- the projection 28 functioning to centerthe flanges 18 and keepthem from cocking whereby thefl'angesare simul taneously and evenly forced against the wire. As the press closes, the wire in the ferrule is squeezed between the corrugations in the ferrule, and since the corrugations in the flanges 18 are offset from the corrugations in the bottom wall of the ferrule, the wire within the ferrule is corrugated as illustrated in Fig. 4, and thereby positively interlocked with the ferrule. Since the corrugations in the opposite sides of the ferrule are offset from each other, the severing and/r necking (reduction in cross section) of the wire often experienced in the past is eliminated. The pressure applied to the ferrule 14 in crimping the same about the wire is sutficient to cause the metal of the wire and of the ferrule to .cold flow to its final form without eliminating the corrugations 20 in the metal of the ferrule. In crimping the ferrule about the wire 22, the ends of the flanges 18 are not forced into the wire as has been common heretofore, and thus the severing of strands of stranded wire usually experienced in the past because of this practice has been eliminated. The resulting shape of the crimped ferrule and wire as shown in Figs. 4 and 8 eliminates any tendency of the wire to shift or turn in the crimped ferrule.

While the corrugations 20 actually stiffen the metal, they also create in the corrugated ferrule a certain amount of give or yieldability which reduces the criticality of the crimp height in the applicator, the give of the corrugated crimp compensating for excess travel of the crimping die. The stiffening of the metal created by the corrugations minimizes or eliminates the relaxing of the grip of the crimped ferrule on the wire.

I have found that the yieldability imparted to the metal stock by the corrugations makes it possible to use a given size ferrule for a large range of wire sizes, thereby eliminating the substantial expense of making different sized dies, as well as the expense of setting up different sized dies in the applicator when different sized wires are to have connectors applied thereto. For example, the .construction herein disclosed makes it possible to construct a ferrule from .017 inch stock which can be applied to wires ranging in size from No. 22 to No. 14 inclusive. It has also been found that with the construction disclosed and for a given size connector, it is possible to use .017 inch stock instead of the .020 to .022 stock heretofore required. It is also preferable that the depth of the corru gations be less than the thickness of the metal stock.

The corrugations on the inside of the ferrule project into the bore of the ferrule and form wire gripping abutments 30 which face away from the connected wire end 32 of the ferrule for resisting axial separation of the wire and the ferrule after the wire is crimped in the ferrule. The construction disclosed provides a substantially more uniform and effective grip between the ferrule and the wire than obtained in the past, and in some cases on pull-out tests the wire breaks before pulling out of the ferrule.

The connector is additionally provided with a second pair of integral flanges 34 at the sides of the ferrule at the connected wire end thereof, such second pair of flanges straddling the insulation 36 covering the wire and having the free ends thereof crimped over and contacting the insulation as shown in Fig. 4 for directly and positively connecting the connector to the insulation. An integral portion 38 connects each flange 18 with a flange 34 and forms a means for stiffening the end of the ferrule 14 and the connector.

While I have illustrated and described a preferred embodiment of my invention, it is understood that this is capable of modification, and I therefore do not wish to be limited to the precise details set forth but desire to avail myself of such changes and alterations as fall within the purview of the following claims.

I claim:

1. An electrical connector element formed from flat metal stock and having an integral ferrule connected with a current conducting wire, said ferrule being formed prior to its connection with said wire to define a longitudinally extending channel having an opening along one side thereof for receiving the end of a wire to which it is to be connected, the opposite sides of said channel which define said opening being provided by lateral flanges which project from the bottom of said channel, the metal stock forming the bottom of said channel and said flanges being formed to provide stiffening corrugations in the metal transversely of the channel, the corrugations in said flanges being aligned with each other but offset from the corrugations in the bottom of said channel, the corrugations on the inside of the channel being formed to define wire gripping abutments for resisting axial separation of said Wire and said ferrule after the ferrule is crimped around said wire, a current conducting wire having its end seated in said channel, the free ends of said flanges being crimped over and contacting said end of said wire seated in said channel so as to squeeze said Wire end between the corrugations of said flanges and the corrugations in the bottom of said channel, thereby corrugating said wire end and positively interlocking the same with said ferrule.

2. An electrical connector element formed from flat metal stock and having a ferrule connected with a current conducting wire, said ferrule being formed to define a longitudinally extending channel for receiving the end of a wire to which it is to be connected, the metal stock forming the ferrule being formed to provide metal stiffening corrugations transversely of the channel, the corrugations in one side of said channel being offset from the corrugations in the opposite side of said channel, the corrugations on the inside of the channel being formed to define wire gripping abutments for resisting axial separation of said wire and said ferrule after the wire is crimped in said ferrule, a current conducting wire having its end seated in said channel, the corrugated sides of said channel being crimped over and contacting said end of said wire seated in said channel so as to squeeze said wire end between the oflset corrugations thereof, thereby corrugating said wire end and positively interlocking the same with said ferrule.

3. A device according to claim 1 wherein said connector element is provided with a second pair of integral flanges at the sides of said channel at the connected wire end thereof, said second pair of flanges straddling the insulation covering said wire and having the free ends thereof crimped over and contacting said insulation for directly and positively connecting said connector element to said insulation, said connector element having an integral portion at the side of the channel interconnecting each set of first and second flanges respectively and forming a means for stiffening the end of said ferrule and said connector element.

4. An article of manufacturing comprising an electrical connector element formedfrom flat metal stock and having an integral ferrule portion formed for connection with a current conducting wire, said ferrule portion being formed prior to its connection with said wire to define a longitudinally extending channel having an opening along one side thereof for receiving the end of a wire to which it is to be connected, the opposite sides of said channel which defines said opening being provided by integral flanges which project from the bottom of said channel, the metal stock forming the bottom of said channel and said flanges being formed to provide metal stiffening corrugations transversely of the channel, the corrugations in said flanges being aligned with each other but oilset from the corrugations in the bottom of said channel, the corrugations on the inside of the channel forming wire gripping abutments facing away from the connected wire end of the channel for resisting axial separation of said Wire and said ferrule after the wire is crimped in said ferrule.

5. An article of manufacturing according to claim 4 wherein the depth of said corrugations is less than the thickness of the metal stock of said connector element.

6. An electrical connector element formed from flat metal stock and having an integral ferrule crimped on a bare current conducting wire, said ferrule being formed prior to its crimping on said wire to define a longitudinally extending channel having an open side for receiving the end of a wire to which it is to be connected, the metal stock forming said channel being formed to provide metal stiffening corrugations transversely of the channel on opposite sides thereof and with the corrugations on one side out of alignment with those on the other side, the corrugations on the inside of the channel being formed to define wire gripping abutments engageable with said wire for corrugating the same when the ferrule is crimped on said Wire for resisting axial separation of said wire and said ferrule after the wire is crimped in said ferrule, a current conducting wire having its end seated in said channel, said channel being crimped over and contacting said end of said Wire seated in said channel so as to squeeze said Wire end between the corrugations thereof, thereby positively interlocking the wire with said ferrule.

7. An electrical connector element having one portion thereof formed for connection with a second connector element and an integral ferrule portion formed for connection with a bare current conducting wire, said ferrule portion being formed prior to its connection with said wire to define a longitudinally extending channel having an opening along one side thereof for receiving the end of a Wire to which it is to be connected, the metal stock forming said channel being corrugated transversely of the channel on opposite sides thereof with the corrugations on one side out of alignment with those on the other, the depth of said coriugations being less than the thickness of the metal stock and the corrugations on the inside of the channel forming wire gripping abutrnents engageable with said wire for c-orrugating the same when the ferrule portion is crimped on said wire for resisting axial separation of said Wire and said ferrule after the wire is crimped in said ferrule.

References Cited in the file of this patent UNITED STATES PATENTS 1,262,155 Zimmerman Apr. 9, 1918

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