US3503284A - Cable drill - Google Patents

Description

March 31, 1970 J. w. SWINEFORD 3,503,284

CABLE DRILL Filed April 30, 1968 l/V VE/V TOR. JOHN W. SWINEFORD A I forneys United States Patent O M 3,503,284 CABLE DRILL John W. Swineford, Glenshaw, Pa., assignor to Goss Gas, Inc., Glenshaw, Pa., a corporation of Pennsylvania Filed Apr. 30, 1968, Ser. No. 725,453

Int. Cl. B231) 45/06 US. Cl. 77-7 4 Claims ABSTRACT OF THE DISCLOSURE This patent discloses a cable drill that is substantially less expensive to manufacture than the ones that are now used and, at the same time, more advantageous, in that it 18 not necessary to use a vise or a pair of wrenches to tighten the drill bit into place and thus prevent it from failing to rotate with the handle of the cable drill when the drill is in use. The handle and the nut securing the drill bit thereto are made of plastic, and the drill bit used has a shoulder that is shaped to fit into the handle.

BACKGROUND OF THE INVENTION Field of the invention This invention relates to cable drills for use in cutting lead sheathing of telephone cables or the like.

Description of the prior art For about the last thirty years, it has been common to protect against moisture that might otherwise be contained in a lead-sheathed telephone cable by pressurizing the cable with dry nitrogen gas. In doing this, holes are drilled through the outer lead sheathing of the cable at spaced intervals along its length, the holes are tapped to provide internal threads, and suitable fittings from a gas-supply system are threaded into the openings.

One form of cable drill commonly used comprises five parts: body, nut, plug-ejector pin, compression spring, and bit. The body has a handle portion and a shaft portion, with the latter being hollow to contain the plugejeector pin, spring and bit, and being exteriorly threaded on its end remote from the handle so that the nut be secured to it. The plug-ejector pin is a piece of mild steel, generally cylindrical and with a shoulder near one end, upon which the spring bears. The handle portion of the body has an opening through which one end of the plug-ejector pin protrudes. The spring is a compression spring with squared ends, one end bearing on the shoulder of the plug-ejector pin and another end bearing on a shoulder of the bit. The bit is made of hardened alloy steel and is, typically, a double bit, being generally tubular in shape with teeth at each end and a centrally located shoulder against which the compression spring bears. When the teeth at one end of the bit become worn, the cable drill is disassembled and the bit is reversed to bring its other end into use. The nut, typically made of mild steel, has interior threads that mate with the exterior threads of the body. The handle portion of the body is about two inches in diameter, and its shaft portion is about two inches long; the drill bit cuts a hole about /5 inch in diameter.

Cable drills as described above have two main disadvantages. First, they are substantially more costly to manufacture than those of the present invention. Second, unless the nut is tightened to the body portion with the use of a vise or a pair of Wrenches, the shoulder of the bit is not securely enough held, so that when an attempt is made to drill through the lead sheathing of a telephone cable, the bit does not rotate with the handle and the desired cutting action is not obtained. In the field, it is frequently quite inconvenient to provide the required tightening.

3,503,284 Patented Mar. 31, 1970 SUMMARY OF THE INVENTION In accordance with the invention, the above-indicated disadvantages are overcome by providing a cable drill generally similar to that described above, but with the following exceptions. The body and nut are made of plastic. A drill bit having a shoulder of slightly dilferent shape is used; the shoulder is shaped to fit into recesses in the end of the shaft portion of the body remote from the handle. With this structure, mere hand-tightening of the nut will sufiice.

DESCRIPTION OF THE DRAWINGS DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to the drawings, and in particular to FIG. 1, there is shown a cable drill 2 comprising a body 4, an ejector pin 6, a compression spring 8, a nut 10, and a drill bit 12.

The body 4 has a handle portion 14 and a shaft portion 16, which is provided at the end remote from the handle portion 14 with exterior threads 18.

The ejector pin 6 is generally cylindrical and has, at the end near the handle 14, a shoulder 20 that bears against the spring 8.

The nut 10 secures the drill bit 12 to the remainder of the structure, causing the shoulder 22 of the drill bit 12 to be received within recesses 24, best seen in FIG. 2, of the shaft portion 16 of the body member 4. The nut 10 has internal threads 26 which mate with the external threads 18 of the shaft portion 16.

The body member 4 and the nut 10 are made of suitable thermoplastic or thermosetting resinous material. One example of a suitable material is a high-impact styrene-type rigid thermoplastic resin of the kind that is suitable for injection molding, extrusion, or calendering, such as that sold by the Marbon Chemical Division of Borg-Warner Corporation under the trademark Cyco lac. Other suitable materials will, of course, suggest themselves to those skilled in the art.

While I have shown and described herein a certain embodiment of my invention, I intend to cover as well any change or modification therein which may be made without departing from its spirit and scope.

I claim as my invention:

1. A cable drill comprising, in combination:

a body member having a handle portion and a shaft portion, said shaft portion having in the end thereof remote from said handle portion a shaped recess and having thread means in the vicinity of said end of said shaft portion remote from said handle portion,

a bit member having a shoulder portion adapted to be received snugly in said recess to prevent rotatory motion of said bit member with respect to said body member, and

a nut having thread means adapted to mate with said thread means of said body portion to secure said bit member within said body member.

2. A cable drill as defined in claim 1, characterized in that said shaft portion of said body member comprises a bore extending therethrough, said drill further comprising:

an ejector pin received in said bore and adapted to pass through said bit member to eject a plugof I material therefrom upon the completion of a drilling operation, said ejector pin having in the vicinity of said handle end of said body member ashoulder, compression spring received in said bore and encircling portions of said ejector pin and said bit, one end of said spring bearing upon said shoulder of said ejector pin and an opposite end of said spring bearing upon said shoulder portion of said bit memher.

.4 material therefrom upon the completion of a drilling operation, said ejector pin having in the vicinity of said handle end of said body member a shoulder, compression spring received in said bore and encircling portions'of said ejector pin and said bit, one end of said spring bearing upon said shoulder of said ejector pin and an opposite end of said spring bearing upon said shoulder portion of said bit member.

References Cited 3. A cable drill as defined in claim 1, characterized in 10 UNITED STATES PATENTS that said body member and said nut are made of shocke resistant resinous materiaL 1,881,787 10/1932 Mample et al. 77-7 4. A cable drill as defined in claim 3, characterized in that said shaft portion of said body member comprises a 15 FRANCIS Primary Exammer bore extending therethrough, said drill further comprising: U S Cl X R an ejector pin received in said bore and adapted to 77 69 71 pass through said bit member to eject a plug of

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