US3833953A

US3833953A - Dielectric tool

Info

Publication number: US3833953A
Application number: US00427236A
Authority: US
Inventors: J Fisher; D Heck
Original assignee: Illinois Tool Works Inc
Current assignee: Illinois Tool Works Inc
Priority date: 1973-12-21
Filing date: 1973-12-21
Publication date: 1974-09-10
Anticipated expiration: 1991-09-10
Also published as: CA1002791A; FR2255146B1; FR2255146A1

Abstract

A tool for use with electric wires and the like is disclosed. The tool comprises two intersecting arms and pivot means. Each arm includes a core member having a three-part work edge at one end and a triangular handle portion at the other end. Dielectric material covers substantially the entire core member of each arm, and forms a T-shaped arm handle with the core member being buried in the T base. The nose is tapered in two planes to permit use in restricted work areas.

Description

United States Patent 1191 1111 3,833,953 Fisher et al. Sept. 10, 1974 [54] DIELECTRIC TOOL 2,511,187 6/1950 Weidauer 30/341 x 1 1 nvenorn Julian nsner, Carpenersnne; 33322332? 1311328 wilfiijijiiiiiijf" I1II.. 3 6li4 i g Hwk, Deerfield, both of 3,082,652 3/1963 Marti 81/415 731 Assignee: Illinois Tool Works 1116., Chicago, Primwy laminae-James sm Attorney, Agent, or Firm-Olson, Trexler, Wolters, Bushnell & Fosse, Ltd. [22] Flled: Dec. 21, 1973 [21] Appl. No.: 427,236 [57] ABSTRACT A tool for use with electric wires and the like is dis- 152 us. 0 7/5.s, 81/415, 81/416, closed- The tool Comprises two intersecting arms and 42 pivot means. Each arm includes a core member having 51 1111. C1 B25b 7/02, B25b 7/06, B25b 7/22 a three-Part work edge at one end and a triangular 5 Field f Search 81/418, 5 416, 25 R, handle portion at the other end. Dielectric material 81/420 W54, 55, 3 30/341, 260. covers substantially the entire core member of each 29 H arm, and forms a T-shaped arm handle with the core member being buried in the T base. The nose is ta- [56] References Cited pered in two planes to permit use in restricted work UNITED STATES PATENTS areas 2,488,484 11/1949 Vander Clute 81/420 x 17 Claims, 7 Drfiwlng Figures 66 64' lbi ,1

74 I A I, 5-% rag 74 a 1 DIELECTRIC TOOL BACKGROUND OF THE INVENTION This invention relates generally to tools, and more particularly to tools such as pliers and the like.

It is the general object of the present invention to provide an improved, rugged, inexpensive plier-like tool especially adapted for working with electrical wires which will have a long service life.

It is also an object of the invention to provide a plierlike tool for use with hot electrical wires which discourages inadvertent shorts or electrical contact with nearby conductive objects when the tool user is manipulating the tool and an engaged wire.

Another object of the invention is to provide a tool especially adapted to cut insulated electrical wires, such as common 20 or 22 gauge copper wire, to strip surrounding insulation from the wire adjacent the cut end, and to manipulate the cut and stripped wire end.

Other objects and advantages of the invention will become apparent upon reading the following detailed description and upon reference to the drawings. Throughout the description, like reference numerals refer to like parts.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a plan or elevational view of the novel tool in its overall aspect;

FIG. 2 is a perspective fragmentary view showing the nose and pivot mechanism of the novel tool;

FIG. 3 is a sectional view taken substantially in the plane of line 33 in FIG. 1;

FIG. 4 is a sectional view taken substantially in the plane of line 4-4 in FIG. 1;

FIG. 5 is a sectional view taken substantially in the plane of line 5-5 in FIG. 1;

FIG. 6 is an exploded view similar to FIG. 2 an showing the tool arms and pivot parts in further detail; and

FIG. 7 is an exploded view showing the-arm core members used in the present novel tool.

\ with a preferred embodiment, it will be understood that it is not intended to limit the invention to that embodiment. On the contrary, it is intended to cover all alternatives, modifications and equivalents as may be included within the spirit and scope of the invention.

Turning first to FIG. 1, the novel tool It) may be considered to comprise two

opposed arms

11 and 12 interconnected for swinging motion about a common pivot axis. The tool 10 and each

constituent arm

11 and 12 can be further considered to have a nose portion 16, a pivot portion 17, and a handle portion 18. Surrounding the pivot portions 17 of the arms is a pivot mechanism 19 which functionally defines the tool pivot axis. Reference to FIGS. 4 and 5 in particular will reveal that each

arm

11 and 12 comprises a respective

metallic core member

21 or 22 and a surrounding dielectric member 23Ior 24. In accordance with one aspect of the invention, this

dielectric member

23 or 24 covers substantially the entire surface of the

core member

21 and 22 and prevents electrically conductive contact, except as explained below, between the

core members

21 and 22 and any nearby wire workpiece or other electrically conductive object.

In accordance with another aspect of the invention, the pivot mechanism 19 includes a tube nut 27, here formed of dielectric material similar to that used for the

cover members

23 and 24. The tube nut 27 has an axial portion 28 adapted to mate with

bores

29 and 30 formed in the arms II and 12 to provide a smooth, easy-acting pivoting action for the tool. In the illustrated embodiment, these

bores

29 and 30 are also formed of dielectric material and cover the

core member

21 and 22 at the respective bores.

To retain the

arms

11 and 12 and the tube nut 27 in interengagement, an annular flange 32 on the tube nut 27 is adapted to mate with an annular recessed seat 33 on one arm 11. Mating with the other arm 12 is a retainer device, here including a screw member 35 provided with relatively hard male threads 36. When the tool 10 is assembled, these hard metallic male threads 36 engage a relatively soft inner bore 37 of the tube nut 27, and such introduction forms mating female threads in the tube nut bore 27. When so constructed, the manufactured cost of the tool is lowered, and relatively permanent interconnection of the parts is encouraged. Surrounding the head 39 of the securing screw 35 is a dielectric washer 40 formed and adapted to engage an annular seat 41 on the opposite arm 12.

In accordance with yet another aspect of the invention, the

core members

21 and 22 each comprise metallic stampings of substantially uniform thickness to reduce the manufactured cost of the tool. It will be noted that the

core members

21 and 22, shown in FIG. 7 are each provided with respective nose portions 45 and 46, pivot portions 47 and 48 and handle portions 49 and 50.

It is a feature of the invention that the nose portions 45 and 46 are aligned with the respective handle portions 49 and 50, but the pivot portions 47 and 48 are offset with respect to the adjacent nose portions 45 and 46 and handle portions 49 and 50. This offset permits a layer of dielectric material 52 and 53 to be interposed between the

core members

21 and 22 and surface of the oppsite arm as shown in FIG. 4. In the illustrated embodiment, the pivot portion 17 of the tool is interposed between the nose portion 16 and the arm portion 18.

Extending away from the pivot portion 17 of the tool is the handle portion 18. In accordance with still another aspect of the invention, each

armhandle

23 and 24 includes a generally triangular core member 49 and 50, truncated at one end and imbedded within the surrounding layer of

dielectric material

57 and 58. The

dielectric cover portions

57 and 58 located on each

arm

11 and 12, respectively, each includes a flange portion 60 and 61, here made entirely of dielectric material, which extend perpendicularly to the core handle portions 49 and 50 along respective first edges 62 and 63,

handle

portion edges

65 and 66 extend along at least portions of the tool handle arms 18. These edges and the covering dielectric material are positioned to abuttingly engage one another. This abutting engagement prevents excessive closing strain from being applied to the tool parts. To permit the tool user to insert his finger between portions of the closed tool arm handles 18 and readily manipulate the tool,

tail portions

70 and 71 are formed outwardly adjacent the interior

abutting handle edges

65 and 66, and are spaced apart from one another and from the tail portion on the opposite arm when the tool is closed as illustrated in FIG. 1.

In accordance with a still further aspect of the invention, the nose 16 is tapered to a point 74 in two mutually perpendicular planes, as illustrated in FIGS. 1, 3 and 4. This nose shape permits insertion of the tool nose into restricted work areas such as electrical connection boxes and the like. Moreover, dielectric outer surfaces 75 are presented in the Work area to prevent electrical conduction should the nose 16 inadvertantly contact electrical potentials in the work area. Shock to the tool user is thus prevented, and inadvertant shorting between differing electrical potentials is avoided.

When the nose 16 is opened, as illustrated in FIG. 2, it can be seen that each arm is provided with a dielectric triangular

interior nose surface

77 and 78, and that the respective core member work edges 79 and 80 (see FIG. 1) protrude above the

interior nose surfaces

77 and 78. These work edges 79 and 80 are each located along the altitude of the respective

triangular surfaces

77 and 78 in abutting relationship with the opposite work edge. It is another feature of the invention that these work edges 79 and 80 each include serrated portions 83 and 84 adapted to grip a wire or other workpiece, recessed

planar portions

85 and 86 adapted to engage and strip insulation from a wire, and converging

edge portions

87 and 88 of substantially knife-edge cross-sectional aspect (see FIG. 3) adapted to cut the wire or other workpiece. The converging knife-

edge portion

87 and 88 can be formed by a coining operation, if desired. As illustrated in FIG. 2, stop members 89 and 90 are formed between the work edges 79 and 80 and the tool pivot mechanism 19 to prevent the wire or other workpiece from sliding too far toward the pivot and becoming jammed in the tool mechanism.

Pursuant to the invention, the three work edge configurations are arrayed in the order illustrated. Thus, by progressive movement of the tool, a wire workpiece can be cut, then stripped of insulation, and finally gripped for manipulation, all by relatively easy, uniform movement of the tool.

Manufacture of the

tool arm members

11 and 12 is relatively easy. After the

core members

21 and 22 are formed, they can be mounted or clipped in place within an injection mold cavity by attachment of the

core member

21 or 22 to a support at pre-designated clip points 9396. Complete arm production is then accomplished by injecting dielectric plastic material into the injection mold, thereby forming the illustrated arm and covering the core member except along a protected work edge 79 and 80 and at the clip points. These mold attachment clip points 9396 here include small

triangular areas

93 and 94 at the arm noses and small circular areas 95 and 96 adjacent the base of the arm handle. It is a feature of the invention that, when the clip points are located as described, they are located at positions which inhibit contact between the exposed metal of the core members and electrically charged workpieces at any point except the core member work edges 79 and 80. Inadvertent shock to the tool manipulator or shorting of a workpiece is thereby correspondingly inhibited.

The invention is claimed as follows:

1. A tool comprising a pair of intersecting arms each including a metallic core member and a dielectric cover member, and pivot means interconnecting the arms for swinging motion about a common axis, the pivot means including a dielectric tube nut having an axial portion adapted to mate with bores in the arms, and having an annular flange portion adapted to mate with an annular recessed seat on one arm, the pivot means further including retainer means adapted to engage the tube nut axial portion and dielectrically engage the opposite arm so as to retain the arms and the pivot means in their assembled position.

2. A tool according to claim 1 wherein said retainer means includes a dielectric washer means adapted to engage an annular seat on said opposite arm, and screw means for securing the washer means to the tube nut and on the arm seat.

3. A tool according to claim 2 wherein said screw means is provided with relatively hard male threads and said tube nut is provided with a relatively soft inner nut bore surface, the male screw threads upon introduction into the inner nut bore surface, forming mating female threads thereon.

4. A tool according to claim 1 wherein said dielectric cover member forms each arm pivot bore and covers each metallic core member at its respective bore.

5. A tool comprising a pair of intersecting arms and pivot means interconnecting the arms for swinging motion about a common axis, the arms each including a metallic core member and having at least one work edge, a dielectric cover member covering substantially the entire surface of the core member except the work edge, thereby inhibiting contact of the core member with other electrically conductive objects at any place except the work edge.

6. A tool according to claim 5 wherein each core member includes a nose portion, a handle portion aligned with the nose portion and a pivot portion offset from the nose and handle portions to permit a layer of dielectric material to be interposed between said core member and the surface of the opposite arm.

7. A tool according to claim 6 wherein said pivot portion is located between said nose portion and said handle portion.

8. A tool according to claim 6 wherein said core member comprises a metallic stamping of substantially uniform thickness.

9. A tool according to claim 6 wherein said core member includes a handle portion and said dielectric cover member includes a flange portion extending perpendicularly to said core handle portion at one edge thereof, thereby forming an arm handle portion of substantially T-shape in cross-sectional aspect.

10. A tool according to claim 5 wherein said work edge includes a serrated portion adapted to grip a wire workpiece, a recessed planar portion adapted to engage and strip insulation from a wire workpiece, and a converging edge portion of substantially knife-edge cross-sectional aspect adapted to cut a wire workpiece.

11. A tool according to claim wherein said recessed planar portion is located between said serrated portion and said converging edge portion, thereby permitting a wire workpiece to be cut, stripped of insulation, and gripped for manipulation by progressive movement of the tool.

12. A tool comprising a pair of intersecting arms and pivot means interconnecting the arms for swinging motion about a common axis, the arms each comprising a tool nose portion, a tool pivot portion and tool handle portion, and each arm further including a metallic core member and a dielectric cover member, each core member including a planar handle portion of substantially triangular shape, a first triangular edge extending along at least a portion of the tool handle exterior and a second triangular edge extending along at least a portion of the tool handle interior, that portion of the tool handle interior being positioned to abuttingly engage a corresponding tool handle interior portion on the opposite arm to prevent excessive closing strain from being applied to the tool parts.

13. A tool according to claim 12 wherein said dielectric cover member includes a flange portion extending perpendicularly to said planar core handle portion at said first triangular edge, thereby forming an arm handle portion of substantially T-shape in cross-sectional aspect, the core member being enclosed within at least the base of the T.

14. A tool according to claim 12 including a tail portion formed on said tool handle portion, the tail portion being formed to be spaced apart from the tail portion on the opposite arm when the tool is closed, thereby permitting the tool user to insert fingers between the portions of the closed tool arm handles for tool manipulation.

15. A tool comprising a pair of intersecting arms and pivot means interconnecting the arms for swinging motion about a common axis, the arms each including a metallic core member and a dielectric cover member, the assembled tool including a nose, a pivot and a handle, the tool nose being tapered to a point in two mutually perpendicular planes for insertion into restricted work areas, and presenting dielectric outer surfaces for preventing electrical conduction when the nose contacts electrically differing potentials in said restricted work areas.

16. A tool according to claim 15 wherein each arm is provided with a dielectric triangular interior nose surface and includes a work edge protruding above the interior nose surface and located along the altitude of the triangular surface in abutting relationship with the work edge protruding above the opposite arm nose surface.

17. A tool comprising a pair of intersecting arms and pivot means interconnecting the arms for swinging motion about a common axis, the arms each including a metallic core member having a work edge and an injection molded dielectric cover member covering the entire core member except the work edge and at least one clip point adapted to locate the core member within the injection mold during arm production, the exposed clip point being located on the arm at a position inhibiting contact between the clip point and an electrically charged workpiece.

Claims

11. A tool according to claim 10 wherein said recessed planar portion is located between said serrated portion and said converging edge portion, thereby permitting a wire workpiece to be cut, stripped of insulation, and gripped for manipulation by progressive movement of the tool.