US3625623A

US3625623A - Apparatus for boring radial holes in a coaxial cable

Info

Publication number: US3625623A
Application number: US15162A
Authority: US
Inventors: William A Rheinfelder
Original assignee: RJ Communication Products Inc
Current assignee: RJ Communication Products Inc
Priority date: 1970-02-27
Filing date: 1970-02-27
Publication date: 1971-12-07
Anticipated expiration: 1988-12-07

Abstract

Certain types of couplers utilized in tapping a coaxial cable intermediate along its length require boring a plurality of radial holes in the coaxial cable to closely regulated predetermined depths and without shorting the inner and outer conductors. Tool apparatus for boring such holes is provided and consists of a tool block having a cable-receiving channel disposed across one of its surfaces and a clamp member for securing a coaxial cable in the channel. A plurality of threaded apertures extend from the bottom of the channel through the tool block to the opposite surface. A hollow tubular tool holder is threaded along a portion of its length and provided with a stop shoulder adjacent the thread termination such that it may be introduced into the threaded apertures and screwed down until the shoulder abuts the tool block surface. A hollow cylindrical tool provided with peripheral teeth at one end is secured within the tool holder in a predetermined position such that, when the tool holder is screwed home, a circular cut of the desired depth is directed radially in the coaxial cable. Where a cut through the inner conductor is required, the surface of the tool block against which the tool holder shoulder abuts is undercut to the desired extent to permit the necessary deeper cut. Subsequently, a second nonthreaded tool holder, used in conjunction with a modified drill bit, is introduced into the tool block apertures after the circular cut has been made and twisted to remove the core.

Description

UnitedStates Patent [72] Inventor William A. Rheinielder Phoenix, Ariz.

[211 App]. No. 15,162

[22] Filed Feb. 27, 1970 [45] Patented Dec. 7, 1971 [73] Assignee RJCommunicatlon Products, Inc.

[54] APPARATUS FOR BORING RADIAL HOLES IN A COAXIAL CABLE 3 Claims, 8 Drawing Figs.

[52] US. Cl 408/97, 408/l0l. 408/l02 [5 l] Int. Cl. B23h 49/02 [50] Field 0! Search 408/97, 101, 102

[56] References Cited UNITED STATES PATENTS 1,638,230 8/l927 Alsaker- 408/102 X Primary Examiner-Francis S. Husar Attorney-Drumrnond, Cahill & Phillips ABSTRACT: Certain types of couplers utilized in tapping a coaxial cable intermediate along its length require boring a plurality of radial holes in the coaxial cable to closely regulated predetermined depths and without shorting the inner and outer conductors. Tool apparatus for boring such holes is provided and consists of a tool block having a cable-receiving channel disposed across one of its surfaces and a clamp member for securing a coaxial cable in the channel. A plurality of threaded apertures extend from the bottom of the channel through the tool block to the opposite surface. A hollow tubular tool holder is threaded along a portion of its length and provided with a stop shoulder adjacent the thread termination such that it may be introduced into the threaded apertures and screwed down until the shoulder abuts the tool block surface. A hollow cylindrical tool provided with peripheral teeth at one end is secured within the tool holder in a predetermined position such that, when the tool holder is screwed home, a circular cut of the desired depth is directed radially in the coaxial cable. Where a cut through the inner conductor is required, the surface of the tool block against which the tool holder shoulder abuts is undercut to the desired extent to permit the necessary deeper cut. Subsequently, a second nonthreaded tool holder, used in conjunction with a modified drill bit, is introduced into the tool block apertures after the circular cut has been made and twisted to remove the Core.

PATENTEUDEI: nan

SHEET 1 BF 3 INVENTOR.

WILLIAM A. RHEINFELDER ATTORNEYS PATENTED DEC 7 I971 SHEET 2 BF 3 INVENTOR. W|LL|AM, A RHEINFELDER BY ATTORNEYS PATENTEUHEB mn- 3525623 sum 3 or 3 'IIIII/IIII IF/III Bikini INVENTOR.

WILLIAM A. RHEINFELDER BY gz mx away/wo- ATTORNEYS APPARATUS FOR BORING RADIAL HOLES IN A COAXIAL CABLE This invention relates to cutting tools and, more particularly, to tool apparatus for boring closely controlled radial holes in coaxial cable.

The necessity for providing convenient connectors for coupling to a coaxial television cable has become more acute with the advent of cable television (CATV). Typically, a CATV system will utilize extensive antenna and receiving equipment for receiving and amplifying a television signal. The receiving equipment is connected to a main trunk which may also be provided with suitable repeaters to maintain signal strength along the cable. The main trunk link will usually service a number of feeder lines, and the latter will ordinarily be installed in a neighborhood and be positioned along the telephone poles or perhaps underground in the case of underground utility service. The feeder lines are typically coaxial cables having a single solid inner conductor of copper and a single solid tubular aluminum outer conductor with dielectric material between the two to maintain positioning. A plastic sheath will normally surround the cable.

The feeder lines are tapped at convenient locations to provide the appropriate television signal to individual dwellings through smaller coaxial cables called house drops. A house drop cable is usually formed of a single solid inner copper wire surrounded by a semiflexible plastic material which supports a braided copper outer conductor. The entire cable is covered with an insulating and weatherproofing sheath. The tap on the feeder line is normally installed by semiskilled personnel unacquainted with the complexities of high-frequency signal transmission and the problems that can be caused by improperly or poorly installed taps; further, the environment in which the tap or coupler exists dictates that the coupler be weatherproofed and be completely impervious to moisture and other elements.

A coaxial cable coupler which has been found especially useful for tapping such feeder lines is disclosed in my copending applications, Ser. No. 801,700, filed Feb. 24, I969, entitled Method and Apparatus for Coupling to a Coaxial Cable and Ser. No. 834,323, filed June 18, 1969, entitled Connector for Attachment to a Coaxial Cable. While the connector disclosed therein functions with highly desirable characteristics, the use of the referenced connector requires the prior boring of a plurality of radial holes in the coaxial cable to be tapped, and these holes must be carefully controlled as to depth while completely avoiding the shorting of the inner and outer conductors since the tapping operation typically occurs while the coaxial cable is carrying a signal. In a preferred embodiment, the coupler requires drilling three closely spaced radial holes in the coaxial cable with the center hole severing the inner conductor and both outer holes piercing only the outer conductor.

It is a broad object of this invention to provide tool ap paratus for boring closely controlled radial holes in a coaxial cable.

It is a more specific object of this invention to provide tool apparatus for boring a plurality of radial holes in a coaxial cable at predetermined mutual positions along the length of the cable and to predetermined depths.

These objects are achieved, according to a presently preferred embodiment of the invention, by providing a tool block having a cable receiving channel across one of its surfaces and a clamp member for securing a coaxial cable therein. Three spaced-apart threaded apertures extend from the bottom of the channel through the tool block to the opposite surface. The threaded apertures accommodate a tubular tool holder which is threaded along a portion of its length and which is provided with a shoulder adjacent the thread termination which abuts the tool block surface to limit precisely the depth to which the coaxial cable is penetrated. The boring operation is carried out by a hollow cylindrical tool secured within the tool holder in a predetermined position. The hollow cylindrical tool is provided, at its working end, with longitudinally directed saw teeth arranged in a circular pattern. The

tool holder is provided, on the unthreaded portion of its outer surface, with a hexagonal shape such that it may be screwed down with a wrench thereby making a circular cut to a predetermined depth in the coaxial cable. In the pattern contemplated, the center one of the three holes must be cut deeper than the outer holes in order to sever the inner conductor as well as penetrate the outer conductor. The additional cutting depth is effected by undercutting the surface of the tool block around the center aperture where the tool holder shoulder abuts the tool block surface. After a circular cut has been made, a core remains which is removed by using a second, nonthreaded work holder in conjunction with a modified drill bit which is introduced into the tool block apertures and twisted to ream the core out.

The subject matter of the invention is particularly pointed out and distinctly claimed in the'concluding portion of the specification. The invention, however, both as to organization and method of operation, may best be understood by reference to the following description taken in connection with the accompanying drawing, of which:

FIG. I is a perspective view of the tool block of the present invention showing the tool block clamp in position;

FIG. 2 is a cross-sectional view of the tool block of FIG. 1 taken along the lines 2--2;

FIG. 3 is a cross-sectional view of the tool block of FIG. 1 taken along the lines 33;

FIG. 4 is a perspective view of the cutting tool of the present invention;

FIG. 5 is a perspective cutaway view of the tool holder which accommodates the cutting tool of FIG. 4;

FIG. 6 is a plan view of the core removing tool;

FIG. 7 is a perspective cutaway view of the tool holder for the core removing tool illustrated in FIG. 6; and

FIG. 8 is a cross-sectional view of the tool block with a coaxial cable in place showing the cutting and reaming tools in position at the termination of cutting and core removing operations, respectively.

Referring now to FIG. 1, it will be observed that a tool block 1 has a channel 2 which extends across the whole of one of its surfaces. A clamp support member 3 is secured to the tool block 1 and extends upwardly beyond the surface in which the channel 2 is formed. The clamp support member 3 is provided with a plurality of apertures 4 for receiving a corresponding plurality of projections for guiding and securing a clamp member 5 in position. The clamp member 5 is provided with a channel 6 which, when the clamp member 5 is in position on the tool block I, complements the channel 2 in the tool block I to provide a passageway of substantially circular cross section. A threaded stud 7 projects upwardly from the tool block 1 through a hole in the clamp member 5 and receives a nut 8 which functions to tighten the clamp member 5 in position.

FIG. 2 is a cross section of the tool block I taken along the lines 2-2 of FIG. I and FIG. 3 is a cross section of the tool block 1 taken along the lines 3-3 of FIG. 1. The manner in which the clamp support member 3 is secured to the tool block 1 is best shown in FIG. 2 where it will be observed that a first bolt 9 and a second bolt (not shown) from the cutaway portion fixes the clamp support member 3 rigidly to the tool block 1. First, second and third threaded tool guide apertures 10, I1, and I2, extend through the body of the tool block I from the bottom of the channel 2 to the opposite surface 13 of the tool block I. The first and third tool guide apertures 10 and I2 terminate flush with the surface 13. However, the second tool guide aperture 11 is provided with an undercut I4 which creates a shoulder depressed below the surface 13. The reason for the undercut I4 will become apparent as the description proceeds. The passageway comprising the complementary channels 6 and 2 has an approximately circular cross section as may be seen in FIG. 2. The dimensions of the channels 2 and 6 are such that a coaxial cable to be tapped is held snugly within the passageway by tightening the nut 8 onto the stud 7.

The threaded tool guide apertures 10, 11, ad 12 receive a tool holder 21, shown in FIG. 5, containing a cutting tool 15 illustrated in FIG. 4. Referring to FIG. 4, the cutting tool 15 is a hollow tubular structure with a passageway 16 extending throughout its length. The working and of the tool 15 terminates in a plurality of circumferentially disposed sawteeth l7 brought to a sharp serrated leading edge 18 and extending rearwardly and outwardly. The area to the rear of the sawteeth 17 is machined to a smaller diameter to avoid shorting the outer conductor to the inner conductor in those boring operations in which the center conductor is secured. A pair of flat areas 19 and 20 disposed 90 apart, are provided at the rearward end of the cutting tool 15 for securing it in place within the tool holder 21 of FIG. 5.

Referring now to FIG. 5, the tool holder 21 generally comprises a hollow tubular structure provided with threads 22 cut into a reduced diameter portion of its length. The forward and rearward sections of the interior have, respectively, larger and smaller diameters such that the transition area between the two diameters effects an internal circumferential shoulder 23. The rearward external portion 24 of the tool holder 21 is in a hexagonal configuration to facilitate applying the necessary torque to perform the cutting operation as will be explained more fully below. An internally threaded washer 25 provides an external shoulder to control the depth to which the tool holder 21 may be screwed home. A threaded aperture 26 and a second threaded aperture (not shown in FIG. 5) receives set screws which are tightened against the flat areas 19 and 20 of the cutting tool 15 of FIG. 4 when the cutting tool 15 is inserted in the tool holder 21 and fitted against the internal shoulder 23.

FIG. 6 illustrates a second tool 27 generally comprising a drill bit with a specially configured leading edge 28 directed approximately 1 from normal to the longitudinal axis of the tool 27. A pair of

flat areas

29 and 30 are provided at the rearward end of the tool 27 for securing the tool within its work holder.

The work holder for receiving the tool 27 of FIG. 6 is depicted in FIG. 7, and generally comprises a hollow tubular structure having a circular external configuration along a first portion 31 of its length with the remaining rearward portion 32 having a hexagonal configuration. An undercut 33 between the portions 31 and 32 provides a positive seat on the forward face 34 of the portion 32. A first threaded aperture 35 and a second threaded aperture (not shown) disposed 90 from the aperture 35 are adapted to receive set screws for securing the tool 27 of FlG. 6 in position after it has been seated against the internal shoulder 36 within the bore of the tool holder 37.

The manner of using the tool apparatus is best understood with reference to FIG. 8 which depicts the first tool holder 21 with the tool 15 in place screwed home in the threaded tool guide aperture 11 and the second tool holder 37 with the tool 27 in place bottomed in the threaded tool guide aperture 12. It will be understood that the normal use of the

tool holders

21 and 37 is sequential rather than simultaneous, the latter shown in FlG. 8 merely for purposes of illustration. A coaxial cable 38 is inserted into the passageway comprising the channels 2 and 6 (FIGS. 1 and 2) and is fixed in place by tightening the clamp 5. The coaxial cable 38, shown in cross section in FIG. 8, consists of an inner conductor 39, an outer circumferential conductor 40, insulating dielectric material 41 separating the inner and outer conductors and an outer insulating cover 42. As previously noted, the tool apparatus is used to bore a center radial hole in the coaxial cable which penetrates the outer conductor and severs the inner conductor 39. This operation is performed by introducing the tool holder 21 into the center tool guide aperture 11 and screwing it down utilizing a suitable wrench on the hexagonally shaped rearward portion 24 of the tool holder. The tool holder 21 is thus screwed down until the washer 25 seats against the bottom of the undercut 14 at which point the penetration is substantially as shown in FIG. 8 where it will be observed that the sawteeth 17 of the cutting tool 15 have severed the inner conductor 39 leaving a core extending into the passageway 16 of the tool 15.

As previously noted, the center tool guide aperture 11 is flanked by outer

tool guide apertures

10 and 12 which are not provided with an undercut corresponding to the undercut 14. Thus, when the tool holder 21 is introduced into the

tool guide apertures

10 and 12, the surface 13 of the tool block 1 provides a stop limiting the depth of penetration short of the inner conductor 39 of the coaxial cable 38. In FIG. 8, the coaxial cable adjacent the tool guide aperture 12 has been bored in accordance with the requirement for the outer holes whereas the coaxial cable adjacent the tool guide aperture 10 has not yet been tapped.

In the normal sequence of operations, all three positions are first bored using the tool holder 21 in conjunction with the cutting tool 15 leaving three cores of material to be removed. The cores are removed by introducing the tool 27, in its tool holder 37, successively into the tool guide apertures 10, II and 12 and twisting in a clockwise direction, utilizing a wrench on the hexagonal surface 32, if necessary, to ream out the core material thereby providing a cleanly defined hole. The specially configured leading edge 28 of the tool 27 insures a substantially fiat bottom to the radial holes cut into the coaxial cable 38 for proper accommodation of the coupler subsequently attached after removal of the coaxial cable 38 from the tool block 1.

While the principles of the invention have now been made clear in an illustrative embodiment, there will be immediately obvious to those skilled in the art many modifications of structure, arrangement, proportions, the elements, materials, and components, used in the practice of the invention which are particularly adapted for specific environments and operating requirements without departing from those principles.

lelaim:

1. Apparatus for boring and clearing holes to a predetermined depth in a coaxial cable, comprising:

a. a tool block, said tool block being provided with a first channel extending across the full length of a first one of its surfaces, said first channel configured to substantially conform to a portion of the outer surface of a coaxial cable, a clamp member adapted for use with said tool block, said clamp member having a second channel disposed in parallel with and superimposed over said first channel, means for tightening said clamp member against said tool block, said first and second channels cooperating to form a passageway substantially conforming to the outer surface of a coaxial cable such that a second of coaxial cable disposed in said passageway is securely held when said clamp member is tightened against said block, a tool guide aperture extending through said tool block, said tool guide aperture disposed perpendicular to said first channel and said first surface, said tool guide aperture being threaded along at least a portion of its length;

b. a tool holder, said tool holder comprising a coaxially bored tubular structure having a threaded portion along its outer surface for threaded engagement with said tool guide aperture, the coaxial bore through said tool holder including first and second portions with corresponding first and second diameters, said first diameter being larger than said second diameter, a step transition between said first diameter and said second diameter providing an internal shoulder, circumferential external shoulder means on the periphery of said tool holder adjacent the terminus of said threaded portion for limiting the distance through which said tool holder may be threaded into said tool guide aperture; and

c. a tubular cutting tool adapted to be inserted into and fixed in said tool holder, a first end of said cutting tool configured in a plurality of longitudinally directed sawteeth arranged in a circular pattern, a second end of said cutting tool dimensioned to seat against said internal shoulder in said first tool holder to define the relative longitudinal relationship between said tool holder and said cutting tool.

2. Apparatus for boring and clearing holes to a predetermined depth in a coaxial cable, comprising:

a. a tool block, said tool block being provided with a first channel extending across the full length of a first one of its surfaces, said first channel configured to substantially conform to a portion of the outer surface of a coaxial cable, a clamp member adapted for use with said tool block, said clamp member having a second channel disposed in parallel with and superimposed over said first channel, means for tightening said clamp member against said tool block, said first and second channels cooperating to form a passageway substantially conforming to the outer surface of a coaxial cable such that a second of coaxial cable disposed in said passageway is securely held when said clamp member is tightened against said block, a plurality of tool guide apertures extending through said tool block, each of said tool guide apertures disposed perpendicular to said first channel and said first surface, each of said tool guide apertures intercepting said first channel symmetrically, each of said tool guide apertures being threaded along at least a portion of its length;

b. a first tool holder, said first tool holder comprising a coaxially bored tubular structure having a threaded portion along its outer surface for threaded engagement with any one of said plurality of said tool guide apertures, the coaxial bore through said first toolholder including first and second portions with corresponding first and second diameters, said first diameter being larger than said second diameter, a step transition between said first diameter and said second diameter providing an internal shoulder, circumferential external shoulder means on the periphery of said first tool holder adjacent the terminus of said threaded portion for limiting the distance through which said first tool holder may be threaded into one of said plurality of said tool guide apertures; and

c. a tubular cutting tool adapted to be inserted into and fixed in said first tool holder, a first end of said cutting tool configured in a plurality of longitudinally directed sawteeth arranged in a circular pattern, a second end of said cutting tool dimensioned to seat against said internal shoulder in said first tool holder to define the relative longitudinal relationship between said first tool holder and said cutting tool.

3. The apparatus of claim 2, which further includes:

a. a second tool holder, said second tool holder comprising a coaxially bored tubular structure, the coaxial bore through said second tool holder including first and second portions with corresponding third and fourth diameters, said third diameter being larger than said fourth diameter, a step transition between said third diameter and said fourth diameter providing an internal shoulder within said second tool holder, second external shoulder means on the periphery of said second tool holder for limiting the distance through which said second tool holder may be threaded into one of said plurality of said tool guide apertures; and I b. a reaming tool adapted to be inserted into and fixed in said second tool holder, said reaming tool dimensioned to seat against said internal shoulder within said second tool holder to define the relative longitudinal relationship between said second tool holder and said reaming tool.

Claims

1. Apparatus for boring and clearing holes to a predetermined depth in a coaxial cable, comprising: a. a tool block, said tool block being provided with a first channel extending across the full length of a first one of its surfaces, said first channel configured to substantially conform to a portion of the outer surface of a coaxial cable, a clamp member adapted for use with said tool block, said clamp member having a second channel disposed in parallel with and superimposed over said first channel, means for tightening said clamp member against said tool block, said first and second channels cooperating to form a passageway substantially conforming to the outer surface of a coaxial cable such that a second of coaxial cable disposed in said passageway is securely held when said clamp member is tightened against said block, a tool guide aperture extending through said tool block, said tool guide aperture disposed perpendicular to said first channel and said first surface, said tool guide aperture being threaded along at least a portion of its length; b. a tool holder, said tool holder comprising a coaxially bored tubular structure having a threaded portion along its outer surface for threaded engagement with said tool guide aperture, the coaxial bore through said tool holder including first and second portions with corresponding first and second diameters, said first diameter being larger than said second diameter, a step transition between said first diameter and said second diameter providing an internal shoulder, circumferential external shoulder means on the periphery of said tool holder adjacent the terminus of said threaded portion for limiting the distance through which said tool holder may be threaded into said tool guide aperture; and c. a tubular cutting tool adapted to be inserted into and fixed in said tool holder, a first end of said cutting tool configured in a plurality of longitudinally directed sawteeth arranged in a circular pattern, a second end of said cutting tool dimensioned to seat against said internal shoulder in said first tool holder to define the relative longitudinal relationship between said tool holder and said cutting tool.

2. Apparatus for boring and clearing holes to a predetermined depth in a coaxial cable, comprising: a. a tool block, said tool block being provided with a first channel extending across the full length of a first one of its surfaces, said first channel configured to substantially conform to a portion of the outer surface of a coaxial cable, a clamp member adapted for use with said tool block, said clamp member having a second channel disposed in parallel with and superimposed over said first channel, means for tightening said clamp member against said tool block, said first and second channels cooperating to form a passageway substantially conforming to the outer surface of a coaxial cable such that a second of coaxial cable disposed in said passageway is securely held when said clamp member is tightened against said block, a plurality of tool guide apertures extending through said tool block, each of said tool guide apertures disposed perpendicular to said first channel and said first surface, each of said tool guide apertures intercepting said first channel symmetrically, each of said tool guide apertures being threaded along at least a portion of its length; b. a first tool holDer, said first tool holder comprising a coaxially bored tubular structure having a threaded portion along its outer surface for threaded engagement with any one of said plurality of said tool guide apertures, the coaxial bore through said first tool holder including first and second portions with corresponding first and second diameters, said first diameter being larger than said second diameter, a step transition between said first diameter and said second diameter providing an internal shoulder, circumferential external shoulder means on the periphery of said first tool holder adjacent the terminus of said threaded portion for limiting the distance through which said first tool holder may be threaded into one of said plurality of said tool guide apertures; and c. a tubular cutting tool adapted to be inserted into and fixed in said first tool holder, a first end of said cutting tool configured in a plurality of longitudinally directed sawteeth arranged in a circular pattern, a second end of said cutting tool dimensioned to seat against said internal shoulder in said first tool holder to define the relative longitudinal relationship between said first tool holder and said cutting tool.

3. The apparatus of claim 2, which further includes: a. a second tool holder, said second tool holder comprising a coaxially bored tubular structure, the coaxial bore through said second tool holder including first and second portions with corresponding third and fourth diameters, said third diameter being larger than said fourth diameter, a step transition between said third diameter and said fourth diameter providing an internal shoulder within said second tool holder, second external shoulder means on the periphery of said second tool holder for limiting the distance through which said second tool holder may be threaded into one of said plurality of said tool guide apertures; and b. a reaming tool adapted to be inserted into and fixed in said second tool holder, said reaming tool dimensioned to seat against said internal shoulder within said second tool holder to define the relative longitudinal relationship between said second tool holder and said reaming tool.