US3683319A

US3683319A - Notched plate clasp apparatus

Info

Publication number: US3683319A
Application number: US84286A
Authority: US
Inventors: George Henry Vigeant; James Albert Kloth
Original assignee: AMP Inc
Current assignee: TE Connectivity Corp
Priority date: 1970-10-27
Filing date: 1970-10-27
Publication date: 1972-08-08
Anticipated expiration: 1989-08-08
Also published as: DE2152250C3; CA938360A; GB1362416A; AU3347771A; AU465068B2; SE366431B; DE2152250B2; ES198136U; NL7113690A; BE774374A; AT317330B; FR2113254A5; BR7106950D0; NL150956B; DE2152250A1; ES198136Y; JPS5527429B1

Abstract

A clasp apparatus including two pairs of cantilever flanges which provide resilient cantilever action to resiliently grip and clasp a length of strand material inserted therebetween. The flanges are provided with slicing edges which slice and partially penetrate into the strand material. The flanges are further mounted on webs spanning between uprights which themselves are deformable in resilient cantilever action for applying compression on the gripped and clasped strand material. Alternatively, the uprights may be provided with stiffeners for reducing the cantilever action thereof. The first pair of flanges cooperate with the second pair of partially compress a longitudinal portion of the strand material spanning between the pairs of flanges.

Description

United States Patent Vigeant et al.

[ 1 Aug. 8, 1972 [54] NOTCHED PLATE CLASP APPARATUS [72] Inventors: George Henry Vigeant; James Albert Kloth, both of St. Petersburg,

211 Appl. No.: 84,286

[52] US. Cl. ..339/97 R [51] Int. Cl. ..H0lr11/20 [58] Field of Search ..248/74 A, 316 R, 316 D; 24/255 C, 259 C, 257; 339/97 I, 97 R, 98, 99 R [56] References Cited UNITED STATES PATENTS 2,694,189 11/1954 Wirsching ..339/97 R 3,162,501 12/1964 Wahl ..339/98 FOREIGN PATENTS OR APPLICATIONS 1,144,346 3/1969 Great Britain ..248/316 D Primary Examiner-Donald A. Griffin Attorney-William J. Keating, Ronald D. Grefe, Gerald K. Kita, Frederick W. Raring and Jay L. Seitchik [57] ABSTRACT A clasp apparatus including two pairs of cantilever flanges which provide resilient cantilever action to resiliently grip and clasp a length of strand material inserted therebetween. The flanges are provided with slicing edges which slice and partially penetrate into the strand material. The flanges are further mounted on webs spanning between uprights which themselves are deformable in resilient cantilever action for applying compression on the gripped and clasped strand material. Alternatively, the uprights may be provided with stiffeners for reducing the cantilever action thereof. The first pair of flanges cooperate with the second pair of partially compress a longitudinal portion of the strand material spanning between the pairs of flanges,

14 Claims, 4 Drawing Figures PATENTEDAUB 8 1912 INVENTORS GEORGE HENRY VIGEANT JAMES ALBERT KLOTH NOTCI-IED PLATE CLASP APPARATUS FIELD OF THE INVENTION aiid resiliently grip and clasp, a length of strand materia BRIEF DESCRIPTION OF THE PREFERRED EMBODIMENTS According to one preferred embodiment, a notched plate clasp includes a first pair of uprights connected together by a web portion. The web portion is provided with an elongated notch extending generally parallel to the uprights. The web portion is deformed into a projecting dimple which defines two generally diagonally projecting flanges on either side of the notch.

A second pair of uprights is connected to the first pair of uprights by bight portions, and are connected to each other by a web portion having an elongated notch therein. In similar fashion, the web portion is dimpled to provide a diagonally extending flange on either side of the notch.

In operation, a length of strand material is inserted into both notches. During such insertion, the strand engages against the flanges on either side of the notches with the result that the flanges are resiliently deformed in cantilever action to widen the notches and allow insertion of the strand material therein. The resulting residual resilient cantilever action of the flanges tends to compress the flanges into gripping and clasping relationship on the strand material. The flanges associated with one notch cooperate with the flanges associated with the other notch to partially compress a longitudinal portion of the strand material spanning between the notches. Thus, such residual compression action provides relief for stresses encountered by the strand material during insertion thereof. As an additional feature, the flanges are provided with slicing edges which slice into and partially penetrate the strand material during insertion thereof, thereby insuring retention of the strand material.

In one preferred embodiment, the uprights are fixedly mounted to a base and themselves operate as cantilever beams which are resiliently deformed in cantilever fashion upon insertion of the strand material, and which provide residual resilient cantilever action for additionally gripping and clasping the inserted strand material.

In another preferred embodiment, the fixedly mounted uprights are each provided with a stiffening flange which substantially reduces or eliminates cantil- OBJECTS OF THE INVENTION It is therefore an object of the present invention to provide a notched plate clasp apparatus for gripping and clasping strand material upon insertion thereof in the apparatus.

Another object of the present invention is to provide a clasp apparatus with two pairs of resiliently deformable cantilever flanges, which resiliently clasp and grip a length of strand material therebetween.

A further object of the present invention is to provide a clasp apparatus with two pairs of resiliently deformable cantilever flanges which resiliently clasp and grip a strand material therebetween, and wherein the flanges are provided with slicing edges which slice and penetrate partially into the strand material upon insertion thereof in the clasp apparatus.

Yet another object of the present invention is to provide a clasp apparatus with resiliently deformable cantilever flanges respectively mounted on uprights which are resiliently deformable in cantilever action for applying compression on a strand material gripped and clasped between the flanges.

Yet a further object of the present invention is to provide a clasp apparatus with two pairs of flanges which resiliently clasp and grip a length of strand material therebetween, and wherein the first pair of flanges cooperate with the second pair to partially compress a longitudinal 'portion of the inserted strand material.

Still another object of the present invention is to provide a clasp apparatus having resiliently deformable flanges which resiliently clasp and grip a length of strand material therebetween, and wherein the flanges are mounted on uprights provided with stiffener flanges for either substantially reducing or effectively eliminating cantilever action of the uprights.

Still a further object of the present invention is to provide a clasp apparatus with two pairs of resiliently deformable cantilever flanges for resiliently clamping and gripping a strand material therebetween, and wherein each pair of the flanges is provided on a dimpled web portion extending between a pair of uprights with the flanges projecting diagonally toward each other.

It is yet another object of the present invention to provide a clasp apparatus with resiliently deformable flanges which grip a strand material in the form of an electrical conductor, together with slicing edges on the flanges which slice and penetrate through an insulation layer of the electrical conductor, thereby enabling the flanges to mechanically and electrically engage the conductor.

Other objects and many attendant advantages of the present invention will be apparent upon perusal of the detailed description thereof taken in conjunction with the accompanying drawing.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a perspective of a preferred embodiment of the notched plate clasp apparatus according to the present invention;

FIG. 2 is an elevation of the preferred embodiment illustrated in FIG. 1;

FIG. 3 is a section taken along "the line 3-3 of FIG. 2; and

FIG. 4 is a perspective of another preferred embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS With more particular reference to FIG. 1 of the drawings, there is shown generally at 1, a slotted plate clasp apparatus including a pair of

uprights

2 and 4 connected together by a web portion 6. As shown in FIG. 2, the web portion 6 is provided therein with an elongated notch 8 extending generally parallel with the

uprights

2 and 4 and terminating in a generally circular terminal end portion 10. The other end of the notch 8 communicates with generally L-

shaped notches

12 and 14 provided in the end 16 of the web 6 and located at one end of the notch portion 8. Together, the adjacent portions 12 and 14'define an enlarged recessed opening immediately adjacent to one end of the notch portion 8. Additionally, the

recessed portions

12 and 14 define

elongated flanges

18 and 20, shown in FIG. 1, which extend between the

recessed portions

12 and 14 and the circular end portion of the notch portion 8. Additionally, the

flanges

18 and 20 have substantially parallel sidewalls which define the sides of the notch portion 8. Additionally, the web portion 6 is provided with a bulged protuberance or dimple 22 extending laterally between the

uprights

2 and 4 and extending in partial encircling relationship around the sides of the elongated notch portion 8 and the circular end portion 10 of the notch portion. As shown in FIGS. l-3, the bulge portion 22 positions the

flanges

18 and 20 out of alignment with respect to each other. More particularly, the flanges l8 and 20 extend generally toward each other but project in mutually oppositely extending diagonal directions. Thus, the notch portion 8 defined between the

flanges

18 and 20 is located offset from an imaginary plane visualized as extending between the

uprights

2 and 4. As shown in FIG. 3, the

flanges

18 and 20 are provided respectively thereof with longitudinally extending sharpened cutting or slicing

edges

23 and 24 in opposed spaced relationship adjacent to the notch portion 8.

With reference to FIGS 1 and 3, a second pair of

elongated uprights

26 and 28 are located adjacent respectively to the

uprights

2 and 4. The second pair of uprights are similar in configuration to the

uprights

2 and 4 and are connected thereto by

bight portions

30 and 32. More particularly, the bight portion 30 connects one end portion of the upright 2 to a corresponding end portion of the upright 26. The bight portion 32 connects one end of the upright 4 to a corresponding end of the upright 28. A web portion 34 extends between the

uprights

26 and 28 and is similar in configuration to the web 6. A dimpled portion of the web 34 is provided with a notch portion 36 similar in configuration to the notch portion 8. Two diagonally projecting

flanges

38 and 40, of a configuration corresponding to the flanges l8 and 20, are provided with longitudinally extending opposed cutting or

slicing edges

42 and 44. As shown in FIGS. 1 and 2,

uprights

2, 4, 26 and 28 are fixedly secured, together with their web portions 6 and 34, to a base shown schematically at 46. For example, the base 46 may advantageously be a part of a housing for the notched plate clasp. As shown, each upright is fixedly mounted at only one end thereof.

In operation, a length of strand material 48 is inserted into the spaced

notch portions

8 and 36 with the

flanges

18, 20, 38 and 40 resiliently gripping and clasping the strand material 48. More particularly, the strand material may comprise an electrical conductor 50 provided with an electrical insulating outer sheath 52. Thus initially, the strand material 48 is positioned readily within the

recessed portions

12 and 14 which align the strand material 48 prior to insertion thereof into the

notch portions

8 and 36. As the strand material is inserted into the

notch portions

8 and 36, the

slicing edges

23, 24, 42 and 44 will slice through insulation sheath 52 and engage against and partially penetrate the electrical conductor 50. If the clasp l is manufactured from an electrical conducting material, the clasp will be mechanically and electrically secured to the conductor 50.

With reference to FIG. 3, a further feature of the invention will be explained in detail. More specifically, insertion of the strand material 48 will engage the flange 18 causing it to pivot or deflect in resilient cantilever action generally about the upright 2. Similarly, the flange 20 will be resiliently pivoted or deflected generally about the upright 4. In similar fashion, the flange 38 will pivot resiliently about the upright 26, and the flange 40 will be resiliently pivoted about the upright 28. Since the cantilever action of each of the flanges is resilient, a residual cantilever action will result, which will tend to pivot the flanges mutually toward one another in their respective directions as shown by the arrows in FIG. 3. Such residual cantilever action insures the strand material 48 to be resiliently gripped and clasped between the pair of

flanges

18 and 20 and also between the pair of

flanges

38 and 40. Additionally, a portion 54 of the strand material which spans between the spaced

notches

8 and 36 will be placed partially in longitudinal compression, resulting from the resilient stored energy of the flanges, 18, 20, 38 and 40 initially created upon inserting the strand andresiliently deforming the flanges to produce the described pivotal deflection. Thus, the resilient deformations of the flanges, and the corresponding stresses created by insertion of the strand, become partially relieved upon compression of the strand portion as described.

A further advantage of the present invention resides in the anchoring effect of the

flanges

18, 20, 38 and 40. More specifically, when the strand is placed in longitudinal tension, the flanges resiliently deform in the direction of the applied tension and thereby resiliently resist the tension. The flanges also anchor the strand in gripped relationship preventing pull-out thereof when longitudinal tension is applied thereto.

Since the

uprights

2 and 26 are each fixedly secured at one end thereof, they may act together as a single cantilever beam resiliently deformable in cantilever action in a direction laterally of said notches. However, to substantially reduce or, alternatively, effectively eliminate such cantilever action a stiffening flange 56 is provided longitudinally along the upright 2, and a corresponding stiffening flange 58 is provided longitudinally on the upright 26. In similar fashion, a stiffening flange 60 is provided longitudinally on the upright 4 and a corresponding stiffening flange 62 is provided longitudinally on the upright 28. Thus, by properly selecting the stiffening flanges with a desired degree of stiffness, one can either substantially reduce or effectively eliminate a tendency for cantilever action in the uprights.

With reference to FIG. 4, another preferred embodiment of the present invention will be described in detail, wherein the structural features which correspond to those in the embodiment illustrated in FIG. 1 are given primed numeral designations. Accordingly, an upright 2' is connected at one end thereof to a corresponding end of an elongated upright 26' by a bight portion 30'. An upright 4' is connected at one end thereof to an elongated upright 28 by a bight portion 32'. Each of the uprights is fixedly secured to a base shown schematically at 46. A web portion extending between the uprights 2' and 4' is provided with diagonally projecting flanges 18' and 20 immediately adjacent to an elongated notch 8 which is similar in configuration to the notch 8 of the embodiment of FIG. 1. However, the notch of the FIG. 4 embodiment is without the circular end portion 10 of the embodiment of FIG. 1. Additionally, the notch 8 is immediately adjacent to tapered

arcuate sidewalls

64 and 66 which function as replacements for the

recess portions

12 and 14 of the FIG. 1 embodiment. Flanges are provided on a web portion extending between the uprights 26' and 28 which correspond to the

flanges

38 and 40 of the FIG. 1 embodiment.

Upon insertion of a length of strand material 48, the flanges l8 and operate in similar fashion to the corresponding

flanges

18 and 20 of the FIG. 1 embodi ment. Additionally, the stiffening

flanges

56, 58, 60 and 62 of the FIG. 1 embodiment are eliminated from the embodiment illustrated in FIG. 4 with the result that the connected uprights 2' and 26 together act as a single cantilever beam. Additionally, the connected uprights 24' and 28' act as a single cantilever beam. Thus, upon insertion of the strand material 48' the

flanges

18 and 20 will operate in similar fashion to the

flanges

18 and 20. In addition, such insertion will engage the uprights causing them to resiliently pivot or deflect in cantilever action about their connection points to the base 46'. Such action pivots the uprights laterally apart. A residual cantilever action results from the resilient pivoting action which tends to pivot the uprights toward one another in the direction of the arrows illustrated in FIG. 4. Such residual cantilever action further provides compression forces on the inserted strand material 48'.

Thus, what has been provided is a notched plate clasp apparatus for gripping and clasping strand material. The clasp apparatus is provided with two pairs of resiliently deformable cantilever flanges which grip and clasp the strand material therebetween. The flanges are provided with slicing edges which slice and penetrate partially into the strand material upon insertion thereof in the apparatus. The flanges are provided on uprights which themselves operate as resilient cantilever beams. Alternatively, the uprights may be provided with stiffening flanges to eliminate or reduce cantilever action as desired.

Other embodiments and modifications of the present invention are to be covered in the scope of the appended claims. For example, the clasp of tee present invention may be advantageously stamped and formed from a single flat piece of malleable metal such as brass. Initially the central portion of the flat piece is punched out in the form of the

notches

8, 10, 12 and 14. Then the dimpled portions like the dimpled portion 22 is formed by stamping. The stiffening flanges 56, 58, 60 and 62 are then bent into position. Lastly, the metal piece is folded back over itself along the

bight portions

30 and 32 to form the uprights in parallel adjacent relationship. Since each flange and a corresponding dimple are formed immediately adjacent to a bight portion, considerable stresses are formed which might tend to shear the bight portion. However, since the metal piece is relatively malleable, plastic deformation will occur at the bight portion to relieve the encountered stresses and prevent shearing on an otherwise weakened area. The present invention is utilized to grip, clasp and slice a wide range of strand diameters, the degree of resilient deformations of the flanges and uprights being a direct result of the particular diameter of strand forcibly inserted in the notches of the invention. Thus the deformations will vary to accept strands of different diameters.

What is claimed is:

1. An electrical clasp apparatus for a length of electrically conducting strand material including:

a base,

a first pair of uprights cantilever mounted to said base,

a web between said first pair of uprights and including a first pair of resilient cantilever flanges defining a first notch portion therebetween,

a second pair of uprights cantilever mounted to said base and connected respectively to said first pair of uprights,

a second web between said second pair of uprights and including a second pair of resilient cantilever flanges defining a second notch portion therebetween, 7

said notch portions being capable of receiving a length of electrically conducting strand material forcibly inserted therein,

said cantilever flanges being resiliently deformable in cantilever action to result in residual cantilever action which provides compression forces on the inserted strand material,

and a stiffener flange on each of said uprights substantially reducing cantilever action thereof.

2. An electrical clasp apparatus for a length of electrically conducting strand material including:

a base,

a first pair of uprights cantilever mounted to said base,

a second web between said second pair of uprights and including a second pair of resilient cantilever flanges defining a second notch portion therebetween,

and wherein each of said first and second pairs of flanges includes a slicing edge thereon adjacent a corresponding notch portion for partially penetrating into a length of electrically conducting strand material inserted in said corresponding notch portion.

3. An electrical clasp apparatus for a length of electrically conducting strand material including:

a base,

a first pair of uprights cantilever mounted to said base,

and wherein said uprights are resilient to provide resilient cantilever action, the connected uprights being connected together at corresponding end portions thereof and acting together as a single cantilever beam resiliently deformable in cantilever action in a direction laterally of said notch portions.

4. An electrical clasp apparatus for a length of electrically conducting strand material including:

a base,

a first pair of uprights cantilever mounted to said base,

and wherein, said flanges of each respective pair thereof extend mutually toward each other in mutually oppositely extending diagonal directions.

5. An electrical clasp apparatus for a length of electrically conducting strand material including:

a base,

a first pair of uprights cantilever mounted to said base,

wherein, said webs are each dimpled to provide a bulged protuberance, and wherein, the flanges are positioned out of alignment with each other and on said protuberance.

6. A one-piece electrical terminal for connection to a length of electrically conducting strand material, comprising:

a malleable metal strip having a pair of first uprights,

a first web connecting said first uprights and provided with a conductor receiving first notch portion therein,

said metal strip having a pair of second uprights,

a second web connecting said second uprights and provided with a conductor receiving second notch portion therein,

one of said first uprights being connected to one of said second uprights to form a single first cantilever beam,

another of said first uprights connected to another of said second uprights to form a single second cantilever beam,

said first and second cantilever beams being resiliently deformable in cantilever action in a direction laterally of said corresponding first and second notch portions upon insertion of a length of electrically conducting strand material in said first and second notches.

7. The structure as recited in claim 6, wherein said first and second webs include electrical conductor slicing edges respectively adjacent said first and second notch portions for slicing into and partially penetrating into a length of strand material inserted into said first and second notch portions.

8. The structure as recited in claim 6, wherein, each of said first and second uprights includes a stiffening flange thereon to limit cantilever action of each of said cantilever beams.

9. The structure as recited in claim 6, wherein, each of said webs includes a pair of flange portions defining a corresponding conductor receiving notch portion of each of said webs, said flange portions being resiliently deformable in cantilever action upon insertion of a length of strand material in each of said notch portions to result in residual cantilever action for resiliently gripping and clasping said length of strand material.

10. The structure as recited in claim 9, wherein each of said flange portions includes a slicing edge thereon adjacent to a corresponding notch for slicing into and partially penetrating into a length of electrically conducting strand material inserted in said notch portions.

11. The structure as recited in claim 9, wherein said flange portions included on each of said webs extend toward each other in mutually oppositely extending diagonal directions, with the flange portions of said first web cooperating with the flange portions on said second web to compress a longitudinal portion of a length of strand material inserted into and spanning between said first and said second notch portions.

12. The structure as recited in claim 11, wherein each of said flange portions includes a slicing edge thereon adjacent to a corresponding notch for slicing into and partially penetrating into a length of electrically conducting strand material inserted in said notch portions.

13. The structure as recited in claim 6, wherein, each of said first and second webs are dimpled to provide a bulged protuberance.

14. The structure as recited in claim 6, and further including: a bight portion connecting one of said first uprights with one of said second uprights to form one of said cantilever beams, and a second bight portion connecting another one of said first uprights with another one of said second uprights to form said second cantilever beam.

Claims

1. An electrical clasp apparatus for a length of electrically conducting strand material including: a base, a first pair of uprights cantilever mounted to said base, a web between said first pair of uprights and including a first pair of resilient cantilever flanges defining a first notch portion therebetween, a second pair of uprights cantilever mounted to said base and connected respectively to said first pair of uprights, a second web between said second pair of uprights and including a second pair of resilient cantilever flanges defining a second notch portion therebetween, said notch portions being capable of receiving a length of electrically conducting strand material forcibly inserted therein, said cantilever flanges being resiliently deformable in cantilever action to result in residual cantilever action which provides compression forces on the inserted strand material, and a stiffener flange on each of said uprights substantially reducing cantilever action thereof.

2. An electrical clasp apparatus for a length of electrically conducting strand material including: a base, a first pair of uprights cantilever mounted to said base, a web between said first pair of uprights aNd including a first pair of resilient cantilever flanges defining a first notch portion therebetween, a second pair of uprights cantilever mounted to said base and connected respectively to said first pair of uprights, a second web between said second pair of uprights and including a second pair of resilient cantilever flanges defining a second notch portion therebetween, said notch portions being capable of receiving a length of electrically conducting strand material forcibly inserted therein, said cantilever flanges being resiliently deformable in cantilever action to result in residual cantilever action which provides compression forces on the inserted strand material, and wherein each of said first and second pairs of flanges includes a slicing edge thereon adjacent a corresponding notch portion for partially penetrating into a length of electrically conducting strand material inserted in said corresponding notch portion.

3. An electrical clasp apparatus for a length of electrically conducting strand material including: a base, a first pair of uprights cantilever mounted to said base, a web between said first pair of uprights and including a first pair of resilient cantilever flanges defining a first notch portion therebetween, a second pair of uprights cantilever mounted to said base and connected respectively to said first pair of uprights, a second web between said second pair of uprights and including a second pair of resilient cantilever flanges defining a second notch portion therebetween, said notch portions being capable of receiving a length of electrically conducting strand material forcibly inserted therein, said cantilever flanges being resiliently deformable in cantilever action to result in residual cantilever action which provides compression forces on the inserted strand material, and wherein said uprights are resilient to provide resilient cantilever action, the connected uprights being connected together at corresponding end portions thereof and acting together as a single cantilever beam resiliently deformable in cantilever action in a direction laterally of said notch portions.

4. An electrical clasp apparatus for a length of electrically conducting strand material including: a base, a first pair of uprights cantilever mounted to said base, a web between said first pair of uprights and including a first pair of resilient cantilever flanges defining a first notch portion therebetween, a second pair of uprights cantilever mounted to said base and connected respectively to said first pair of uprights, a second web between said second pair of uprights and including a second pair of resilient cantilever flanges defining a second notch portion therebetween, said notch portions being capable of receiving a length of electrically conducting strand material forcibly inserted therein, said cantilever flanges being resiliently deformable in cantilever action to result in residual cantilever action which provides compression forces on the inserted strand material, and wherein, said flanges of each respective pair thereof extend mutually toward each other in mutually oppositely extending diagonal directions.

5. An electrical clasp apparatus for a length of electrically conducting strand material including: a base, a first pair of uprights cantilever mounted to said base, a web between said first pair of uprights and including a first pair of resilient cantilever flanges defining a first notch portion therebetween, a second pair of uprights cantilever mounted to said base and connected respectively to said first pair of uprights, a second web between said second pair of uprights and including a second pair of resilient cantilever flanges defining a second notch portion therebetween, said notch portions being capable of receiving a length of electrically conducting strand material forcibly inserted therein, said cantiLever flanges being resiliently deformable in cantilever action to result in residual cantilever action which provides compression forces on the inserted strand material, wherein, said webs are each dimpled to provide a bulged protuberance, and wherein, the flanges are positioned out of alignment with each other and on said protuberance.

6. A one-piece electrical terminal for connection to a length of electrically conducting strand material, comprising: a malleable metal strip having a pair of first uprights, a first web connecting said first uprights and provided with a conductor receiving first notch portion therein, said metal strip having a pair of second uprights, a second web connecting said second uprights and provided with a conductor receiving second notch portion therein, one of said first uprights being connected to one of said second uprights to form a single first cantilever beam, another of said first uprights connected to another of said second uprights to form a single second cantilever beam, said first and second cantilever beams being resiliently deformable in cantilever action in a direction laterally of said corresponding first and second notch portions upon insertion of a length of electrically conducting strand material in said first and second notches.