US3822470A

US3822470A - Trimming tool for coaxial cables

Info

Publication number: US3822470A
Application number: US00308887A
Authority: US
Inventors: D Hildebrand
Original assignee: Individual
Current assignee: Individual
Priority date: 1972-11-22
Filing date: 1972-11-22
Publication date: 1974-07-09
Anticipated expiration: 1991-07-09

Abstract

A trimming tool for coaxial cables having a hand held supporting structure on which is rotatably mounted a circular member. Both the supporting structure and circular member have aligned apertures therein through which a cable to be trimmed is inserted. A cutter mechanism is fixedly mounted on the circular member for rotation therewith. Upon rotation of the circular member trimming of the cable takes place.

Description

ilnited States Patent 1191 Hildebrand 1 I Jul 9', 1974 [54] TOOL FOR 3,071,033 7 H1963 Felts 82/76 [76] Inventor: Donald A. Hildebrand, 7 Sunset Dr.,

Mtd. Rt. N0. 2 Rome N.Y. 13440 Emmmehprams S1HuSar Assistant Examiner-W. R. Briggs Fll'edi 1972 Attorney, Agent, or FirmHarry A. Herbert, Jr.; la 21 Appl. No.: 308,887 cob Efhch [52] US. Cl. 30/901, 82/76 4 I57], CT 51 Int. Cl B26!) 27/00 A mmmmglool for coaxlal Cables havmg a hand held [58] Field of Search .82/78 76 72 75- suppomng Structure on which is mtatably a 30/901 12 '3 7 circular member. Both the supporting structure and 7 circular member have aligned apertures therein [56] References Cited through which a cable to be trimmed is inserted. A cutter mechanism is fixedly-mounted on the circular UNITED STATES PATENTS member for rotation therewith. Upon rotation of the l lj3og thby "8812/97: circular member i i of the cable takes place 0 Son 2,346,314 4/1944 5 Claims, 8 Drawing Figures Lembitz et al 30/95 1 TRIMMING TOOL FOR COAXIAL CABLES 7 BACKGROUND OF THE INVENTION This invention relates generally to a trimming tool for coaxial cables, and, more particularly, to a trimming tool which cuts the outer conductor of a semi-rigid, solid sheathed coaxial cable or the outer covering and braid of flexible coaxial cables.

A coaxial cable usually takes the form of several insulated cable transmission lines and assorted power and service conductors within a protective and shielding sheath. Coaxial cable is also the common name for a single cable transmission-line, which has two conductors having the same axis, one surrounding but insulated from the other. Such coaxial cables give less attenuation at high frequencies than do other ordinary cables at the same length. Thus, they are usually used in connection with radio and other high frequency communication. Although .they are best known for their use in video relay for network television broadcasting, coaxial cables are also extensively used in raliable mechanical and electrical performance from the completed assembly.

Installing connectors is usually a hand operation and for flexible cables, the tools which are needed for this operation are a knife or razor blade, wire strippers, wire cutters and soldering or crimping tools. For rigid or semi-rigid solid sheath cables a tubing cutter, file or hacksaw is added to the list. These tools, however, are not capable of consistently producing the square cuts required to make reliable mechanical and electrical connections without extensive training and practice utilizing the above mentioned tools. In many instances distortion of the cable cross section takes place, along with nicking of conductors and the making of non square cuts with the use of tools heretofore in existence. For a solid-sheath or semi-rigid cable, the cutters of the past would swage cables similar to the operation of a pipe cutter, rather than neatly producing an exacting cut as required in connection operations.

SUMMARY OF THE INVENTION v ably mounted a circular member. Mounted on the circular member is a spring biased cutter and a stop mechanism which is utilized to limit the depth of cut from the cutter. A hand operated drive mechanism is utilized to rotate the circular member and cutter. The base member and the circular member each have a hole in.

their center aligned with one another in which a preselected bushing is secured.

The cable to be trimmed is inserted within the bushing so as to be properly centered for the cutter opera- 2 tion. In operation, thecutter is rotated by any one of several drive mechanisms described hereinbelow and actually cuts or files the solid sheath cable. The design of the cutting head allows for precise adjustment of the depth of the cut, eliminating nicked centerconductors. The arrangement set forth in this invention also allows for theuse of the tool in conjunction with various bushings thereby permitting the cutting of a range of cable sizes rather than restricting the instant invention use to 'a fixed single sized cable. Additionally, the tool can be readily produced in a motorized version with the motor being either hydraulic, pneumatic or electrically powered. Further a second or third cutter can be added to produce a two or three step cut on the cable and to accommodate a wide variety of connectors.

It is therefore an .object of this invention to provide a trimming tool for coaxial cables which may be hand operated and is capable or producing accurate, repeatable trimming of solid sheath coaxial cables.

It is another object of this invention to provide a trimming tool for coaxial cables which can be easily adapted to motorized operation for factory production line use.

A further object of this invention is to provide a trimming tool for coaxial cables'which is capable of cutting various cable sizes.

It is still another object of this invention toprovide a trimming tool for coaxial cables which is suitable for. use with either flexible cables or semi-rigid (solid sheath) cables.

It is still a further object of this invention to provide a trimming tool for coaxial cables which is economical to produce and which utilizes conventional, currently available components that lend themselves to standard mass producing techniques.

For a better understanding of the instant invention, together with other and further objects thereof reference is made to the following description, taken in connection with the accompanying drawing and its scope will be pointed out in the appended claims.

DESCRIPTION-OF THE DRAWING .of bushings utilized with the trimming tool of this invention;

FIG. 3 isan exaggerated front view of a modified cutter arrangement utilized with the trimming tool of this invention; v

FIG. 4'is a front view of a depth gauge capable of regulating the length of coaxial cable to be trimmed by the trimming tool of this invention;

FIG. 5 is a side elevational view of the depth gauge shown in FIG. 4 showing its relation to a cable to be trimmed by the trimming tool of this invention;

FIG. 6 is a front view of a modified hand drive means to be utilized with a trimming tool of this invention;

FIG. 7 is a front view of another modified hand drive means to be utilized'with the trimming tool of this invention; and

FIG. 8 is a front view of a motor drive means to be utilized with the trimming tool of this invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT thereof and a flat base member 16 at the other end on which is rotatably mounted a circular member 18. Within the central portion of base member 16 is an opening 20 through which a cable 21 to be trimmed is inserted in a manner to be described hereinbelow. Circular member 18 also has a central hole 22 therein aligned with hole 20 and is held in position spaced from member 16 by a plurality of bearings 24. Bearings 24 engagethe outer periphery of member 18 and allow for its rotation. It should be noted that the means of securing circular member 18 to base member 16, as shown in FIG. 1 is only a preferred mounting arrangement and can be varied within the scope of this invention. The rotation of circular member 18 takes place about an imaginary axis through the center of hole 20 within base member 16 and hole 22 within member 18. Furthermore, hole 22 within circular member 18 is of a size at least equal to the aperture 20.

Still referring to FIG. 1, circular member 18 has a circular pinion gear 26 mounted on the rear portion thereof. Gear 26 contains an aperture therein of a diameter at least as great as aperture 22 of member 18. Base member 16 has a rack gear 27 mounted on any suitable drive mechanism such as plunger 28 slidably mounted on base member 16. Upon movement of plunger 28 by the thumb of an operator the rack gear 27 engages pinion 26 and thereby causes rotation of circular member 18. Any suitable biasing means such as spring 30 is secured between base member 16 and plunger 28 in order to return plunger 28 to the position shown in FIG. 1, thereby allowing a repeatable sliding motion of plunger 28 to take place.

A cutter mechanism 31 is mounted on circular member 18 in a manner to be described hereinbelow. This cutter mechanism 31 comprises a cutter holder 32 pivotally secured to circular member 18 adjacent hole 22 and is biased toward hole 22 by any suitable biasing means such as spring 34. A cutter 36 is removably secured within holder 32 and can be manufactured of any suitable material such as a small piece of hacksaw blade, file, carborundum or diamond impregnated material. Any suitable adjustable stop means 38 isalso mounted on circular member 18 adjacent an edge 40 of holder 32 so as to regulate the depth of the cut produced by cutter 36. In the instant invention this adjustable stop means 38 is in the form of a screw 42 having a high number of threads per inch thereon utilized in conjunction with a nut 44 which is secured to the circu lar member 18. Since the cutter 36 is in the form of a straight edge, it must rotate at least 360 in order to make a cut completely around cable 21. The construction of the rack gear 27 and pinion gear 26 must therefore be of sufficient size to enable an operator with one sliding motion of plunger 28 to rotate the circular member 18 360.

FIG. 2 illustrates a typical bushing 50 which is inserted within the aperture 20 of base member 12 so as to accomodate a variety of sized cables. This bushing 50 (only one of which being shown in FIG. 2) is of a length L no greater than the width W measured from the outside surface of base member 16 to the outside surface of rotating circular member 18 and has approximately the same outer diameter 52 as the diameter of hole 20 so as to press fit therein. Each bushing 50, however, is made of a different inner diameter 54 which is matched to the size of corresponding cables to be trimmed; Furthermore, each bushing 50 has an outstanding element 56 thereon which engages the flat surface of base member 16 upon insertion into hole 20 so as to prevent bushing 50 from extending to or beyond the cutter 36 (FIG. 1) or cutters 63 (FIG. 3). In this manner any suitable cable 21 to be trimmed may be centrally located within the aperture 20 of base member 12 as well as aperture 22 of circular member 18.

A modified cutter mechanism 60 is shown in FIG. 3 and may replace the cutter mechanism 31 of FIG. 1. Cutter mechanism 60 although involving more elements than mechanism 31 is capable of trimming a cable 21 approximately twice as fast as cutter mechanism 31 shown in FIG. 1. This is due to the utilization of two holders 62 and cutters 63 mounted therein. The holders 62 are pivotally secured to circular member 18 at one end 64, and slidably secured to member 18 by block 67 and linkage 66 at the other end thereof. An adjustable stop means 68 similar to stop means 44 shown in FIG. 1 utilizes a spring 68 to maintain the tension of cutters 63 against any cable 21 to be trimmed. Since two'cutters 63 are utilized in this embodiment it is only necessary to rotate circular member 18 slightly more than 180 to make a complete cut. Thus, for the same plunger travel as in FIG. 1, the diameter of the pinion 26 can be doubled which will correspondingly reduce the thumb pressure or force required to operate the rack plunger 28.

FIGS. 4 and 5 illustrate a depth gauge 70 for the trimming tool 10 of this invention. The depth gauge 70 is made up of an L-shaped member 72 adjustably secured at one end thereof to base member 16 by adjusting screw 74. A guide post 76 best shown in FIG. 5 maintains member 72 in a position parallel to base member 16. Upon adjustment of screw 74 the distance between base member 16 and L-shaped member 72 can be varied so as to vary the insertion distance of cable 21 through aperture 20 in base member 16. This addition to the trimming tool 10 of this invention provides added speed and precision when a number of cable ends must be prepared for a single connector type. F urthermore, guide post 76 may be calibrated to provide settings for various connector types.

FIG. 6 shown an alternate hand driving mechanism 80 in which the thumb operated plunger 28 of FIG. 1 is replaced and operated by a trigger 81 fixedly secured to rack gear 27. This design may be more appropriate since in many instances more force can be applied by a finger other than the thumb.

FIG. 7 discloses the trimming tool 10 of this invention in which a squeeze-type handle 82 is pivotally secured by any suitable securing means 83 to base member 16. An extended portion 84 on handle 82 engages an upstanding element 86 on rack gear 27 so as to enable an operator to utilize all fingers when applying a force to rack gear 27.

FIG. 8 discloses how a lever 90 connected in any conventional manner to any reciprocal type motor 92 may replace the manual operating means. Lever 90 is secured to rack gear 27 in order to utilize a maximum force in reciprocating gear 27.

In operation, when a cable, 21 is to be trimmed, a proper sized bushing 50 corresponding to the size of the cable 21, is inserted within hole .of base member 16 until upstanding element 56 engages member 16. The cable 21 is then inserted within the aperture of bushing 50 to-the extent necessary for the desired cutting or trimming action to take place. With depth gauge 70 in place, adjustment of screw 74 determines the length of cable 21 to be, trimmed. As shown in FIG. 1, handle 14 is held by the fingers and palmof the hand, while the thumb is utilized to operate the rack plunger 28. Sliding movement of plunger 28 causes the rotation of pinion gear 26 as well as circular member 18 and the attached cutter mechanism 31 rotates about the cable axis. In general, it will be necessary to press the plunger 28 several times to complete a cut. This will be a function of the length and pitch of the rack gear 27, the pinion 26 diameter, tension in spring 34, the cutter type and design and the cable diameter andcable sheath material.

Although this invention has been described with reference to particular embodiments it will be understood to those skilled in the art that this invention is als'o capable of a variety of alternate embodiments within the spirit and scope of the appended claims.

As an example of an alternateembodiment, note that thebearings 24 may be eliminated by mounting rotating circular member 18, together with pinion gear 26, on a hollow shaft which would extend through base member 12'. This hollow shaft would be rotatably sup- 6 tween cutting planes, this adjustment meansbeing independently variable for each cutter set.

' Additionally, for designs using a motor, it'i's possible to assemble the handle 14 in ways which'allow thev motor to be mounted inside the handle. In this way, a set of handles incorporating different types of motors, such as hydraulic, pneumatic, rotary or reciprocating electric, could be made having identical exterior diported in base member 12 by means of any of several types of bearings, such as roller or ball bearings, the outer race of which would be non-rotatably fixed to the base member 12. This hollow shaft would accept bushings50, as previously described, said bushings being retained in place within the shaft by any of a variety of devices, such as spring clips fixed to the hollow shaft or to the bushing.

The alternate cutter configuration shown in FIG. 3 could be further modified to employ four cutters 63, arranged in a diamond formation. Also, a variety of biasing arrangements and depth-of-cut adjustment arrangements may be employed in any one or all of these cutter configurations. Furthermore, additional cutters, in any of the configurations described, may be fastened to rotating member 18, but located in one or more planes parallel to the front surface plane of member 18. Such added cutter planes would be spaced away from the original cutting plane by a distance appropriate to the type of cable and connector to be used. Some connector types require two or three step cuts to be made on the cable. The added cutting planes would allow all needed cuts to be made simultaneously. Various means may be used to attach additional cutter sets to rotating. member 18, such attachment to provide means for adjusting both depth of cut into the cable, and spacing bemensions and appropriately located and arranged protruding drive links, such that each handle is interchangeable with any other handle on the remainder of the tool. i

I claim:

1. A trimming tool for coaxial cables comprising a fixed supporting structure having a handle at one end thereof and a base member at the other end, a thin member rotatably mounted adjacent said base member by bearing means secured to said base member, an aperture located within said base member and an aperture located within said rotatable member, said apertures being aligned with one another, a cutter mechanism mounted on said rotatable member adjacent said aperture therein, said cutter mechanism having a pair of cutters pivotably secured to said rotatable member, means mounted on said rotatable member for biasing said cutters toward said aperture in said rotatable member, an adjustable stop means mounted on said rotatable member between said pair of cutters for limiting the depth of a cut produced by said cutter and drive means mounted on said supporting structure operably connected to said rotatable member for rotating said rotatable member whereby said cutter trims a cable inserted within said apertures of said tool when said roa hole therein aligned with said pair of apertures, said drive means comprising a rack gear slidably mounted on said supporting structure, said rack gear engaging said pinion gear causing rotation thereof under the action of a driving force and a means mounted on said supporting structure for biasing said rack gear against a the action of said driving force.

4. A trimming tool for coaxial cables as defined in claim 3 wherein said driving force is in the form of a motor.

5. A trimming tool for coaxial cables as defined in claim 1 further comprising a depth gauge mounted on I said supporting structure for limiting the depth of insertion of a cable through said pair of apertures.

Claims

1. A trimming tool for coaxial cables comprising a fixed supporting structure having a handle at one end thereof and a base member at the other end, a thin member rotatably mounted adjacent said base member by bearing means secured to said base member, an aperture located within said base member and an aperture located within said rotatable member, said apertures being aligned with one another, a cutter mechanism mounted on said rotatable member adjacent said aperture therein, said cutter mechanism having a pair of cutters pivotably secured to said rotatable member, means mounted on said rotatable member for biasing said cutters toward said aperture in said rotatable member, an adjustable stop means mounted on said rotatable member between said pair of cutters for limiting the depth of a cut produced by said cutter and drive means mounted on said supporting structure operably connected to said rotatable member for rotating said rotatable member whereby said cutter trims a cable inserted within said apertures of said tool when said rotatable member is rotated.

2. A trimming tool for coaxial cables as defined in claim 1 further comprising a bushing removably mounted within said aperture in said base member.

3. A trimming tool for coaxial cables as defined in claim 2 further comprising a pinion gear fixedly secured to said rotatable member, said pinion gear having a hole therein aligned with said pair of apertures, said drive means comprising a rack gear slidably mounted on said supporting structure, said rack gear engaging said pinion gear causing rotation thereof under the action of a driving force and a means mounted on said supporting structure for biasing said rack gear against the action of said driving force.

5. A trimming tool for coaxial cables as defined in claim 1 further comprising a depth gauge mounted on said supporting structure for limiting the depth of insertion of a cable through said pair of apertures.