US3891296A

US3891296A - Teeter terminal clamp

Info

Publication number: US3891296A
Application number: US404805A
Authority: US
Inventors: Charles E Gutshall
Original assignee: Elco Industries Inc
Current assignee: Elco Industries Inc
Priority date: 1973-10-09
Filing date: 1973-10-09
Publication date: 1975-06-24
Anticipated expiration: 1992-06-24
Also published as: DE2415344A1; GB1403166A; JPS5065894A; JPS5425627B2; AU6463274A; CA993075A

Abstract

The improved teeter terminal clamp for removably securing the terminal portion of a single conductor or two conductors of the same or different diameters comprises a screw-type fastener with an underhead surface having an integral frustoconical section; a clamping plate apertured and assembled loosely and tiltably on the shank adjacent the head, the plate having on the side adjacent the head an annular inner section, a marginal outer section and a frustoconical intermediate section joining the inner and outer sections, the intermediate section accommodating the frustoconical section of the underhead surface at an intermediate portion thereof when both are in registration, the plate also having on the other side complementary inner, outer and intermediate surfaces and a plurality of spaced ribs extending radially from the complementary intermediate surface towards the shank so as to define the aperture of the plate, the plate also having conductor-engaging, anti-pullout surface irregularities; and means for retaining the plate on the shank adjacent the head.

Description

United States Patent 1 [111 3,891,296 Gutshall June 24, 1975 [5 TEETER TERMINAL CLAMP curing the terminal portion of a single conductor or [75] Inventor: Charles Gutshall, Rockford "L two conductors of the same or different diameters comprises a screw-type fastener with an underhead [73] Assignee: EICO lnduSlrieS, nC., rd. 1- surface having an integral frustoconical section; a clamping plate apertured and assembled loosely and [22] Filed 1973 tiltably on the shank adjacent 'the head, the plate hav- [21] App]. No.: 404,805 ing on the side adjacent the head an annular inner section, a marginal outer section and a frustoconical intermediate section joining the inner and outer sec- [52] U.S. CI. 339/246 [51] Int. Cl H0lr 9/10 Hons mtermFdlate sectlon accommodatmg the [58] Field of Search 339/95 246 263; 151/37 frustoconical section of the underhead surface at an intermediate portion thereof when both are in regis- [56] References Cited tration, the plate also haing on thgother iifde compilementar inner, outer an mterme late su aces an a UNITED STATES PATENTS pluraliti of spaced ribs extending radially from the Poupitch complementary intermediate urface towards the 3,065,442 11/1952 Hubhell et a]. 339/246 Shank so as to define the aperture of the plate the plate also having conductor-engaging, anti-pullout surface irregularities; and means for retaining the plate on the shank adjacent the head.

Primary ExaminerJoseph H. McGlynn Attorney, Agent, or Firm-Neuman, Williams, Anderson & Olson [57] ABSTRACT The improved teeter terminal clamp for removably se- 9 Claims, 9 Drawing Figures I Z4 2 l TEETER TERMINAL CLAMP BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to terminal clamps of the threaded type which are employed to releasably secure the terminal portions of elongated members such as electrical conductors to a workpiece or to each other. More specifically, it relates to an improvement in teeter terminal clamps of the type shown in applicants U.S. Pat. No. 3,744,012 and featuring a clamping plate which teeters or tilts in order to accommodate and securely clamp either a single wire or two wires of the same or different size and in the case of a pair of wires to apply approximately equal clamping loads to each wire.

While the present invention is described with particular reference to threaded terminal clamps specifically designed to cope with the problem of clamping electrical conductors having different sizes or diameters, it should be understood that the invention is not necessarily limited thereto. The inventive conceptsset forth herein can be readily adapted to cope with equal-load clamping problems associated with elongated members in general, as those skilled in the art will recognize in the light of the present disclosure.

2. Description of the Prior Art The art relating to terminal clamps for electrical connectors is highly developed because of the long-existing need for improved means for releasably securing electrical leads, both solid and stranded, wires, cables and other connectors to one another and to terminal posts. This need is dictated in part by the cost, inconvenience and obvious hazards, including shock, electrocution, fire and other destructive consequences which can occur if a hot lead becomes unintentionally and unknowingly unfastened. This need is reflected in part in the establishment of various applicable performance standards by Underwriters Laboratories, Inc. It is reflected in part in the patent art in this field, typical of some of the prior art being U.S. Pat. Nos. 2,151,674, 2,304,711, 2,946,039, 3,050,706 and 3,509,517.

The need and the problems associated therewith are even more acute in connection with clamps which must be readily releasable, yet highly secure when fastening either one or two wires, including pairs of wires of different diameters. Some of the prior art terminal clamps have been specifically designed to have the versatility of accommodating a plurality of electrical wires having different diameters but approximately equal clamping loads. Various approaches include, for example, clamping plates which teeter or rock relative to the shank axis. To permit such teetering, the aperture in the plate may be oversized or, at least, elongated in a direction generally perpendicular to the axis of the wires being accommodated. Some of the prior art patents relating to terminal clamps for accommodating wires of different size include, for example, U.S. Pat.

Nos. 3,081,507, 3,177,456, 3,178,675, 3,191,140,.

3,238,495 and 3,509,521.

. Another problem which the prior art has attempted to solve is the inconvenience and cost of assembling the clamping devices on the threaded fasteners at the job site, particularly when the terminal clamps are very small in size and require a high degree of finger dexterity to install. A related problem arises when removing or unclamping the tenninal clamp to temporarily release, remove or replace the wires. The clamping plate may fall off the shank or even stick or otherwise remain attached to the wires which were clamped thereby.

To cope with these problems, terminal clamps have been fabricated with retaining shoulders or rings integrally formed on the shank itself. These retain the clamping plates on the shank so that the electrician has a preassembled device available for use. In addition, the shoulder positively lifts the plates from the wires as the shank is unthreaded. Prior art devices employing shoulders on the threaded shanks, although not necessarily for retaining terminal clamps, include, for example, U.S. Pat. Nos. 2,192,322, 3,141,722, 3,205,473,

3,372,366 and 3,398,393.

Prior art teeter terminal clamps, however, have suffered from one or more shortcomings. For example, some have been unduly complex, comprise a number of parts, are difficult to assemble or use or are quite costly to manufacture. Some have to be assembled on the job or require a nimble-fingered person to apply. Some are structurally weakened by virtue of the particular configuration required for the clamping function.

Some are lacking in performance characteristics and versatility, particularly in their ability to handle pairs of wires of different diameters with approximately equal holding power. Some do not retain the clamping plate prior to use, or fail to positively lift the clamping plate from the wires when the clamp is unscrewed from the wires, or otherwise require as many as two or more revolutions of the shank before the plate is released from the wires. Some also have the tendency to shave the wire when subjected to excessive pullout forces, thus decreasing the cross-sectional area and electrical conductivity capabilities and also creating short-circuit hazards and undesired contamination from the shavings.

Some, particularly the peakedfor rooftop types, are not well adapted to cope with stranded wire and lend themselves to flattening and related overtightening problems. The captured peak-type terminal clamp, wherein the threads or retaining collar are rolled on or otherwise added to the shank after assembly of the plate thereon, also have the additional disadvantage of an undesirably large space or gap along the.

shank between the undersurface of the head and the beginning of the threaded portion or collar.

One solution to these problems is disclosed in applicants U.S. Pat. No. 3,744,012. The design, however, may result in undesired proneness to die breakage, particularly when producing very small clamps. The present invention represents another solution having reduced proneness to die breakage and resulting in unexpectedly improved performance, particularly with respect to resistance to pullout. The attributes of the present invention are reflected in the following objects.

OBJECTS OF THE INVENTION It is therefore a general object of the present invention to provide an improved teeter terminal clamp overcoming many of the shortcomings and disadvantages of prior art types. It is another general object to provide a low-cost, simplified teeter terminal clamp which in certain embodiments comprises only two easy-to-manufacture components. It is another general object to provide a preassembled teeter terminal clamp which can be quickly and conveniently secured or released and does not require special skills to utilize.

It is a more specific object to provide an improved teeter terminal clamp which can be interchangeably employed to secure the terminal portions of a single wire or a pair of wires, and yet can be released therefrom without requiring many back off revolutions. It is another specific object to provide a clamp which can releasably secure a pair of wires of different sizes to one another or to a terminal post with substantially equal holding forces. It is another specific object to provide a terminal clamp capable of meeting accepted standards for secureness, pullout load and minimum torque at failure and which is not prone to cause shaving of the conductor under high pullout loading.

It is still another specific object to provide a teeter terminal clamp capable of coping with the problems peculiar to the clamping of stranded wire. It is still another specific object to cope with the problems peculiar to peaked or rooftop clamps. It is still another specific object to provide a teeter terminal clamp having a design which does not structurally weaken the components and which is not prone to cause die breakage.

These and other objects will become apparent as the description thereof proceeds.

SUMMARY OF THE INVENTION These objects are achieved by a teeter terminal clamp comprising a threaded shank having a head configured to receive a tool for rotating the shank and an apertured clamping plate loosely and teeterably assembled and retained on the shank adjacent the head. The head has an underhead surface with an integral frustoconical section extending outwardly from the underhead surface concentric with the shank axis and intermediate the inner and outer extremities of the underhead surface. In a specific embodiment, this frustoconical section may take the form of a downwarddepending substantially V-shaped embossment or protrusion.

The clamping plate, which is preferably generally rectilinear, has on the side adjacent the head a generally-annular, preferably discontinuous, inner section, a marginal outer section axially displaced from the head and radially displaced from the shank relative to the inner section, and a generally-frustoconical, preferably discontinuous, connecting section joining the inner and outer sections and complementary to the frustoconical section on the underhead surface but of larger diameter or larger major or minor axes. The two frustoconical sections are coordinated so that the extremity of the underhead section registers with an intermediate portion of the connecting section when the two are in registration, that is, when they are aligned and in contact. In practice, the inner and connecting sections of the plate tend to blend into each other as a single configuration.

On the other side, the clamping plate has a generally complementary configuration, including inner, outer and connecting surfaces, and features a plurality of spaced ribs extending radially from the connecting sur face towards the shank of the fastener so as to delimit the aperture. This allows the upper portion of the aperture to be flared outwardly for enhanced teeterability and wider clearances between the shank and the frustoconical section of the head, thus minimizing die breakage problems when heading the blank. The other side of the clamping plate also has wire-engaging, anti-slip surface irregularities, such as grooves or embossments,

portions of which are at least in part transverse to the axes of the wires being retained.

In a particular embodiment the clamping plate is retained on the threaded shank adjacent the head by an integrally-formed annular collar. At least the lower surface of the collar may be serrated so as to provide a torque-robbing character to the assembly to assure clutch out of the drive tool prior to strip out.

As will be apparent from the drawings, the present invention lends itself to a variety of embodiments. Some of these embodiments are specifically adapted to meet particular needs. As used hereinafter, the terms substantially circular, generally annular and the like are intended to encompass similar structural configurations. The concepts are manifestly applicable to such alternative configurations, as those skilled in the art will recognize in the light of this disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS The present invention will be more clearly understood from the following detailed description of specific embodiments read in conjunction with the accompanying drawings, wherein:

FIG. 1 is a fragmentary elevation view, partly in section, showing on a magnified scale a preferred embodiment of the teeter terminal clamp of the present invention prior to threading it into a workpiece for clamping purposes;

FIG. 2 is similar to FIG. 1 except that it shows the teeter terminal clamp after being threaded into a workpiece for clamping two conductors of different diameters;

FIG. 3 is an elevation view, on a slightly reduced scale as compared with FIGS. 1 and 2, of the headed blank prior to assembling the clamping plate and rolling the threads and retaining collar thereon;

FIG. 4 is a bottom plan view of the blank shown in FIG. 3;

FIG. 5 is a perspective view on an enlarged scale of the clamping plate of the embodiment of the present invention shown in FIG. 1;

FIG. 6 is an overhead plan view of the clamping plate of FIG. 5;

FIG. 7 is a bottom planview of the plate of FIG. 6;

FIG. 8 is a sectional view along the line 8-8 of FIG. 6; and

FIG. 9 is a sectional view along the line 9-9 of FIG. 6.

It should be understood that the drawings are not necessarily to scale and that the embodiments are sometimes illustrated by graphic symbols, phantom lines, diagrammatic representations and fragmentary views. In certain instances, details which are not necessary for an understanding of the present invention or which render other details difficult to perceive may have been omitted. It should be understood, of course, that the invention is not necessarily limited to the particular embodiments illustrated herein.

DETAILED DESCRIPTION OF THE DRAWINGS, INCLUDING PREFERRED EMBODIMENTS Referring to FIG. 1, the teeter terminal clamp of the present invention comprises shank 10 having threads 12 along at least a portion of the length thereof and generally circular head 14 at the upper terminal end as viewed in FIG. 1. Head 14 is slotted, as indicated by slot 16, to receive the blade of a screwdriver for rotation of the shank whereby the clamp may be tightened or loosened. Clamping plate 18 is loosely and teeterably assembled on shank adjacent the undersurface of head 14 by means of retaining collar 22. In alternative embodiments, clamping plate 18 may be generally U-shaped, as suggested by the opposed appendages 23 shown in phantom lines in FIG. 1; or the plate may be retained on the shank by a nut threaded on the shank. 1

Referring to FIG. 2, the undersurface 20 of head 14 and the contacting upper surface of clamping plate 18 are complementarily designed, as described in detail hereinafter, so as to clamp terminal ends of conductors having different diameters, such as

electrical leads

24 and 26 which are being clamped to workpiece 28 in support structure 30. Despite the difference in diameters of

leads

24 and 26, the clamping loads on these leads are substantially identical.

Referring to FIGS. 3 and 4, underhead surface 20 has .at least one, integrally-formed, substantially circular furstoconical section 32 flaring downwardly and outwardly from underhead 20 and concentric with the axis of shank 10 and intermediate the inner and outer extremities of underhead surface 20, that is, between the juncture of the shank with the underhead surface and the outer edge thereof. In the exemplar of FIGS. 14, the frustoconical section 32 comprises a V-shaped protrusion, although the outward portion could be solid as suggested by phantom line 32. As is apparent in FIG. 1, this frustoconical section registers with a generallyfrustoconical section on the upper surface of clamping plate 18 whereby the geometry is such that the clamping plate self-adjusts or tilts to accommodate a single conductor lead or conductor leads of different diameters as portrayed in FIG. 2. Manifestly, the clamp also will accommodate two leads having the same diameter.

Referring to FIGS. 5-9, clamping plate 18 comprises a generally-annular, discontinuous inner section 36 with discontinuous aperture wall 38, a marginal outer section 40, which is displaced axially from the head and radially from the shank in the completed assembly, and a generally-frustoconical, discontinuous connecting section 42 which joins inner section 36 and outer section 40, the discontinuities in the inner and connecting sections being equally spaced and in registration. As can be seen in FIGS. 1 and 2, connecting section 42 accommodates and complements the frustoconical section 32 on the undersurface 20 of head 14. In practice, inner section 36 and connecting section 38 blend into each other and in a sense can be considered an integral frustoconical protrusion complementarily accommodating the frustoconical section 32 on the undersurface 20 of head 14 in teetering relationship.

The aperture in plate 18 defined by inner wall 44, as well as discontinuous wall 38, may be circular or oblong with major and minor axes or otherwise slightly squared off. It is oversized relative to the shank diameter so that plate 18 can teeter, rock or tilt relative to the shank, and thus accommodate wires of different diameters. Discontinuous inner surface 38 of inner section 36 flares radially outwardly towards head 14 so as to enhance such teeterability and at the same time permit a larger diameter for frustoconical connecting section 42. This in turn permits the complementary frustoconical section 32 on the undersurface 20 of head 14 to be displaced farther from the shank. As those skilled in the metal forming arts will recognize, this larger displacement minimizes die breakage problems when heading blanks by conventional techniques.

When

frustoconical sections

32 and 42 are concentrically aligned and in contact, as portrayed in FIG. 1, the lower extremity of section 32 registers with frustoconical section 42 between the upper and lower limits thereof. As shank 10 is threaded into workpiece 28 in support 30 so as to clamp the conductor leads 24 and 26, the lower surface of the clamp contacts the leads; and, if uneven, the plate tilts in a fashion whereby frustoconical surface 32 is caused to slip or slide down frustoconical section 42 on the high side and to ride up on the frustoconical section 42 on the low side. This action continues until the lower surface of plate 18 (or embossments thereon) contacts both leads. Further tightening applies approximately equal loads to the leads.

The lower surface of clamping plate 18 is generally complementary to the upper surface and thus has an inner surface 49, outer surface 50 and connecting surface 51. The transitioning depression 50' results from the metal forming operation.

The lower surface also features wire-engaging, antislip surface irregularities or

embossments

52, 54, 56, 58, 60, 62, 64 and 66 thereon; which frictionally grip or otherwise imbed themselves into the wires to be clamped, thereby preventing the wires from being pulled out or shaken loose accidentally. It should be noted that in all instances the wire gripping embossments 52-66 are disposed perpendicular to the sides of the clamping plate so that in the normal clamping operation at least one and normally two embossments are at right angles to the axes of the leads being clamped. This disposition maximizes the anti-pullout characteristic.

At the same time, the clamping action does not injure or materially reduce the current carrying capacity of the leads, even under substantial pullout loads. This contrasts with certain prior art devices which tend to shave the leads under high pullout loads.

The

embossments

52, 54, 56, 58, 60, 62, 64 and'66 are formed by stamping or otherwise forming

complementary grooves

68, 70, 72, 74, 76, 78, and 82 on the upper surface 40 of plate 18. At the same time, the

upper comer portions

84, 86, 88 and 90 of plate 18 are stamped or otherwise formed so as to direct the corners downwardly producing

downward extremities

92, 94, 96 and 98, respectively.

Annular collar 22 preferably has a series of serrations 100 on the surface towards the workpiece. Such serrations may be of any appropriate form for sharply increasing the torque required to rotate the head 14 and shank 10 when the serrations engage the workpiece 28. As is shown in FIGS. 1 and 2 particularly, the serrations 100 in the preferred embodiment include a plurality of teeth inclined upwardly and outwardly of the shank l0 and of generally symmetrical form. As those skilled in the art will recognize, these will absorb a portion of the driving torque during the last stage of tightening whereby the driving too] can be set to assure clutch out before the threaded fastener is stripped out of the workpiece; such action is referred to herein as torquerobbing.

To assure that annular collar 22 is not pulled up inside the plate upon unthreading shank 10, and to limit the extentof unthreading required to lift plate 18 off the

wires

24 and 26,

ribs

102, 104, 106 and 108 are formed on the complementary undersurfaces of plate 18. These ribs, in effect, define or delimit the aperture in the plate. In practice, they are formed, at least in part, from the metal displaced from the discontinuities in the inner and connecting sections of the upper surface. I

In addition to acting as the contacting surfaces for annular collar 22 when unscrewing the clamp, ribs 102-108 also enhance the anti-pullout characteristics of the clamp. Moreover, the ribbing effect on the plate resulting from the formation of the ribs strengthens the plate whereby the plate thickness can be reduced as much as 20 percent without sacrifice of strength.

EXAMPLE An improved teeter terminal clamp is fabricated substantially in accordance with the embodimentof FIGS. 1-9, employing for the threaded fastener No. 1022 low carbon steel, heat treated to a Rockwell Hardness (C- scale) of about 30-40, and for the plate No. 1050 medium carbon steel, heat treated to a Rockwell Hardness (C-scale) of about 44-48. The screw size is No. with 32 threads per inch and a shank length of about /2 inch; and the plate is approximately a 7/16 inch square.

The resulting clamp is tested for pullout failure using a single strand of No. 8 solid copper wire, the clamp being tightened to a torque of 35 inch-pounds. For comparison, the same test is made using the embodiment of FIGS. l-ll of the aforesaid US. Pat. No. 3,744,0l 2. The results are set forth in the following table:

The design of the present invention is also superior to other prior art designs in pullout loading, resistance to wire shaving, or the like.

From the above description it is apparent that the objects of the present invention have been achieved. While only certain embodiments have been set forth, alternative embodiments and various modifications will be apparent from the above description to those skilled in the art. For example, the complementary frustoconical sections on the head undersurface and clamping plate upper surface, respectively, could under certain circumstances bereversed. These and other altematives are considered equivalents and within the spirit and scope of the present invention.

I claim:

1. A teeter terminal clamp for removably securing the terminal portion of at least one conductor comprising in combination:

a. a threaded shank having a head at one extremity and an entering end portion at the other extremity, said head being configured to cooperate with a tool whereby the shank may be rotated into or out of a threaded aperture, said head having an underhead surface with at least one, integral frustoconical section extending outwardly from said underhead surface concentric with the shank axis and between the inner and outer extremities of the underhead surface;

b. a clamping plate apertured to loosely and teeterably receive said shank, said plate having on the side adjacent said head agenerally-annular inner section with inner surface flaring radially outwardly towards said head, a marginal outer section axially displaced from the head and radially displaced from the shank relative to said inner section, and a generally-frustoconical connecting section joining said inner and outer sections, said connecting section accommodating said frustoconical section on the undersurface of said head whereby the extremity of said frustoconical section on the undersurface of said head registers with an intermediate portion of said connecting section when said frustoconical section on the undersurface of said head and said connecting section are aligned and in contact, said plate also having on the other side generally complementary inner, outer and connecting surfaces and including a plurality of spaced ribs extending radially from said connecting surface to the central aperture of said clamping plate so as to define the inner limits of the central aperture in said plate; said plate also having conductorengaging, anti-slip surface irregularities on said other side thereof; and

means for retaining said plate on said shank spacedly adjacent said head.

2. The clamp of claim 1 wherein said clamping plate is substantially rectilinear and said conductorengaging, anti-slip surface irregularities comprise intersecting embossments spacedly adjacent each of the four corners of the clamping plate substantially perpendicular to the sides thereof, outer comer portions intermediate said embossments being inclined away from said head.

3. The clamp of claim 1 wherein the aperture of said clampingplate has a major and a minor axis.

4. The clamp of claim 1 wherein said generallyannular inner section and said generally-frustoconical connecting section are spacedly discontinuous, the discontinuities being in alignment.

5. The clamp of claim 1 wherein said means for retaining said plate comprises an integrally-formed annular collar spaced from said head sufficiently to accommodate said clamping plate in loose relationship prior to tightening and of sufficient outer diameter to engage said spaced ribs when said plate is in contact with said annular collar.

6. The clamp of claim 5 wherein said integrallyformed annular collar has a plurality of torque-robbing serrations on the surface generally in the direction of said entering end portion.

7. The clamp of claim 6 wherein said plate has at least two opposed appendages extending from margins thereof away from said head and substantially alignable with the axis of said shank.

8. A teeter terminal clamp for removably securing the terminal portion of at least one conductor comprising on combination:

a. a threaded shank having a head at one extremity and an entering end portion at the other extremity, said head being configured to cooperate with a tool whereby the shank may be rotated into or out of a threaded aperture, said head having an underhead surface with at least one, integral frustoconical section extending outwardly from said underhead surface concentric with the shank axis and intermediate the inner and outer extremities of the underhead surface;

b. a substantially-rectilinear clamping plate centrally apertured to loosely and teeterably receive said shank, said plate having on the side adjacent said head a generally annular, spacedly-discontinuous inner section with inner surface flaring radially outwardly towards said head, a marginal outer section axially displaced from the head and radially displaced fron the shank relative to said inner section, and a generally frustoconical, spacedlydiscontinuous intermediate section joining said inner and said outer sections, said intermediate section accommodating said frustoconical section on the undersurface of said head whereby the extremity of said frustoconical section on the undersurface of said head registers with an intermediate portion of said intermediate section when said frustoconical section on the undersurface of said head and said intermediate section are aligned, said plate also having on the other side generally complementary inner, outer and intermediate surfaces and including a plurality of equally-spaced ribs extending radially from said intermediate surface to the central aperture in said plate so as to delimit the central aperture in said plate; said plate also having conductor-engaging, anti-slip intersecting embossments spacedly adjacent each of the four corners of the clamping plate and perpendicular to the sides thereof, outer corner portions intermediate said embossments being inclined away from said head; and

c. means for retaining said plate on said shank spacedly adjacent said head comprising an integrallyformed annular collar spaced from said head sufficiently to accommodate said clamping plate in loose relationship prior to tightening and having an outer diameter to engage said spaced ribs and prevent passage thereover.

9. The clamp of claim 8 wherein said integrallyformed annular collar has a plurality of torque-robbing surface serrations toward said entering end portion, and wherein the inner radial limit of said generallyannular inner section of said plate flares radially outwardly towards said head.

Claims

1. A teeter terminal clamp for removably securing the terminal portion of at least one conductor comprising in combination: a. a threaded shank having a head at one extremity and an entering end portion at the other extremity, said head being configured to cooperate with a tool whereby the shank may be rotated into or out of a threaded aperture, said head having an underhead surface with at least one, integral frustoconical section extending outwardly from said underhead surface concentric with the shank axis and between the inner and outer extremities of the underhead surface; b. a clamping plate apertured to loosely and teeterably receive said shank, said plate having on the side adjacent said head a generally-annular inner section with inner surface flaring radially outwardly towards said head, a marginal outer section axially displaced from the head and radially displaced from the shank relative to said inner section, and a generallyfrustoconical connecting section joining said inner and outer sections, said connecting section accommodating said frustoconical section on the undersurface of said head whereby the extremity of said frustoconical section on the undersurface of said head registers with an intermediate portion of said connecting section when said frustoconical section on the undersurface of said head and said connecting section are aligned and in contact, said plate also having on the other side generally complementary inner, outer and connecting surfaces and including a plurality of spaced ribs extending radially from said connecting surface to the central aperture of said clamping plate so as to define the inner limits of the central aperture in said plate; said plate also having conductor-engaging, anti-slip surface irregularities on said other side thereof; and c. means for retaining said plate on said shank spacedly adjacent said head.

2. The clamp of claim 1 wherein said clamping plate is substantially rectilinear and said conductor-engaging, anti-slip surface irregularities comprise intersecting embossments spacedly adjacent each of the four corners of the clamping plate substantially perpendicular to the sides thereof, outer corner portions intermediate said embossments being inclined away from said head.

3. The clamp of claim 1 wherein the aperture of said clamping plate has a major and a minor axis.

4. The clamp of claim 1 wherein said generally-annular inner section and said generally-frustoconical connecting section are spacedly discontinuous, the discontinuities being in alignment.

6. The clamp of claim 5 wherein said integrally-formed annular collar has a plurality of torque-robbing serrations on the surface generally in the direction of said entering end portion.

8. A teeter terminal clamp for removably securing the terminal portion of at least one conductor comprising on combination: a. a threaded shank having a head at one extremity and an entering end portion at the other extremity, saiD head being configured to cooperate with a tool whereby the shank may be rotated into or out of a threaded aperture, said head having an underhead surface with at least one, integral frustoconical section extending outwardly from said underhead surface concentric with the shank axis and intermediate the inner and outer extremities of the underhead surface; b. a substantially-rectilinear clamping plate centrally apertured to loosely and teeterably receive said shank, said plate having on the side adjacent said head a generally annular, spacedly-discontinuous inner section with inner surface flaring radially outwardly towards said head, a marginal outer section axially displaced from the head and radially displaced fron the shank relative to said inner section, and a generally frustoconical, spacedly-discontinuous intermediate section joining said inner and said outer sections, said intermediate section accommodating said frustoconical section on the undersurface of said head whereby the extremity of said frustoconical section on the undersurface of said head registers with an intermediate portion of said intermediate section when said frustoconical section on the undersurface of said head and said intermediate section are aligned, said plate also having on the other side generally complementary inner, outer and intermediate surfaces and including a plurality of equally-spaced ribs extending radially from said intermediate surface to the central aperture in said plate so as to delimit the central aperture in said plate; said plate also having conductor-engaging, anti-slip intersecting embossments spacedly adjacent each of the four corners of the clamping plate and perpendicular to the sides thereof, outer corner portions intermediate said embossments being inclined away from said head; and c. means for retaining said plate on said shank spacedly adjacent said head comprising an integrally-formed annular collar spaced from said head sufficiently to accommodate said clamping plate in loose relationship prior to tightening and having an outer diameter to engage said spaced ribs and prevent passage thereover.

9. The clamp of claim 8 wherein said integrally-formed annular collar has a plurality of torque-robbing surface serrations toward said entering end portion, and wherein the inner radial limit of said generally-annular inner section of said plate flares radially outwardly towards said head.