1. Field of the Invention
This invention relates to tools for cutting armors and shields of cables. In particular, the invention relates to hand-held tools for cutting armors of cables.
2. Discussion of the Prior Art
A task of removing armored casings off armored and shielded cables is too well familiar to professional and amateurs. Used in a variety of industries, cutting armored cables require strong efforts usually associated with unpleasant cuts, nicked fingers and traumatized knees.
Hand-held tools for removing armored casings have addressed many of the known inconveniences over the years. Widely popular hand-held cable cutters manufactured by SEATEK CO. INC, the assignee of the present invention, have been disclosed in U.S. Pat. Nos. 3,851,387, 4,359,819, and 4,769,909, the disclosures of which are incorporated herein by reference. The tools disclosed in these patents have minimized the need for using hacksaws in the cutting of shielded conduits and allowed the user to cut the armor without the blade touching the conduit or cable materials below the armor. Field proven quality cutters disclosed in these patents accept BX cable from 14/2 to 8/4 and 3/8″ Flex as well as AC, MC & HCF cables.
In use, these tools allow the user to temporarily clamp the cable in the proper position and have its armored casing cut longitudinally by a circular saw. This operation takes only a few seconds. It is absolutely safe and does not damage the wires inside due to the unique built-in depth of cut stop.
Typically, the known cutters have a limited clamping range. To reliably engage cables having various outer diameters, the user operates a thump screw adjusting a distance between a clamping lever and the free end of clamping stud coupled to the thump screw.
Often the user operates a cutter under time and space constrains. Manual operation of the thump screw may add to the inconvenience experienced by the user. For example, balancing on the top of a ladder or crouched on a narrow support, the user may jeopardize his/her safety. Furthermore, a relatively simple and thus time-efficient operation of removing an armed casing may turn into a time-consuming, onerous experience.
As a rule, after a cable has been clamped, the user would generate an additional compressing force applied to clamping levers in order to displace a saw into the armored casing. Sometimes this force may be sufficient to crush the armor by the clamping stud. This, in turn, may damage cable material shielded by the armor.
A need thus exists for a cable clamping system associated with armor cutting tools and operative to automatically adjust a clamping range for differently sized cables.
A further need exists for armor cutting tools operative to minimize direct forces acting upon a clamped cable during cutting armored casings.
Still another need exists for improved, time saving, labor efficient and safe cutting techniques used for removing armored casings off differently dimensioned cables.
The present invention is directed to methods and tools that satisfy these needs. The invention includes a method of cutting an armored casing of variously dimensioned cable without a need to manually readjust a clamping mechanism configured to reliably hold the cable for further cutting operations. A cable is initially received in a cable-receiving channel of a lower housing member. Applying an initial external force to a handle causes a clamping stud to extend at the necessary distance sufficient to clamp the cable between the clamp and the wall of the cable channel.
Subsequently, the user applies an additional force greater than the initial force to displace upper member of the housing towards the lower member. As a consequence, a circular saw housed in the upper member of the housing penetrates the armored casing and produces a longitudinal cut.
Thus, the inventive cutting tool utilizes a system of levers amplifying the clamping motion of the clamping stud while retaining the necessary force to bias the clamped cable against a supporting surface during performing a cutting operation. The inventive tool eliminates a need for manually adjusting a distance between clamping surfaces.
The inventive tool includes two housing members resiliently biased away from one another and hingedly attached to one another. A handle is pivotally mounted on a distal end of one of the housing members and is resiliently biased away therefrom. The handle is operative to pivot in response to an initial force so that its free end, while moving towards the one housing member, causes the clamping stud to follow its displacement until a free end of the stud presses against the cable.
A resilient element is mounted between the handle and the housing member to bias these components away from one another. Having a module of resilience lower than a module of resilience of a spring element biasing the housing members, the resilient element coupled to the clamping is displaced in response to the initial force applied to the handle. Once the stud presses against the cable, a second force greater than the initial force is again applied to the handle and housing members so that the members move to a cutting position, in which the circular saw is enabled to cut the armored casing.
These and other features and aspects of the present invention will be better understood with reference to the following description, figures, and appended claims.
Reference will now be made in detail to several embodiments of the invention that are illustrated in the accompanying drawings. Wherever possible, same or similar reference numerals are used in the drawings and the description to refer to the same or like parts or steps. The drawings are in simplified form and are not to precise scale. For purposes of convenience and clarity only, directional terms, such as top, bottom, left, right, up, down, over, above, below, beneath, proximal, and distant may be used with respect to the drawings. These and similar directional terms should not be construed to limit the scope of the invention in any manner. The words “connect,” “couple,” and similar terms with their inflectional morphemes do not necessarily denote direct and immediate connections, but also include connections through mediate elements or devices. The terms “armor” and “armored casing” are used interchangeably.
Referring to
After reliably securing the armored cable 11 in the channel 22 in the clamping position, the user applies an additional compressive force displacing a housing member 16 relative to the lever handle 18 and causing a circular saw 30 to advance towards and penetrate the armored casing 13. Actuation of a saw handle 32 results in an axial cut of the armor 13.
Turning now to details of the inventive tool 10, the lever handle 18 has a distant end 40 pivotally attached to a distal end 44 (
The lever handle is resiliently loaded by a lever 20 configured as a leaf spring to resist the lever handle's displacement to the clamping position. Coupled to the housing 12 by its proximal end 38 (
The lever 20 has a longitudinal body extending angularly outwards from the housing 12 and terminating in the vicinity of the distal end 40 of the lever handle 18. A distal end 42 (
To clamp the armored cable 111, the clamping stud 24 is displaced towards the cable-receiving channel 22. Depending on an outer diameter of the cable 11, the clamping stud 24 projects into the channel 22 until its free end presses the cable 11 against the supporting surface of the channel 22. Once the cable 11 is reliably locked, the clamping operation is completed, and the armor 13 is ready to be cut.
Displacement of the clamping stud 24 is a result of application of the initial compression force F1 (
In accordance with one embodiment, the distal end 42 of the lever 20 has an opening traversed by a head 26 of the clamping stud 24, as shown in
Alternatively, as shown in
A further factor contributing to limited penetration of the stud 24 into the armored casing 13 (
The formation 62 may have various forms and dimensions. For example,
In accordance with a further aspect of the invention, instead of the longitudinal lever 20, a compression spring 80 (
Turning now the housing 12, it extends along the longitudinal axis A-A (
Housed in one of the members 14, 16 is a resilient element 46 (
Thus, the inventive tool 10 allows the user using one hand to automatically adjust a clamping position for various cable sizes. A further advantage of the inventive tool is the fact that the thin, flexible lever 20 can flex in the clamping position thus preventing crushing the armor by the clamping stud.
This document describes the inventive sound transfer methods and devices implementing these methods for illustration purposes only. Neither the specific embodiments of the invention as a whole, nor those of its features limit the general principles underlying the invention. In particular, the invention is not limited to a cable-cutting tool, but includes various clamping devices operating in accordance with the inventive principle. The specific features described herein may be used in some embodiments, but not in others, without departure from the spirit and scope of the invention as set forth. Many additional modifications are intended in the foregoing disclosure, and it will be appreciated by those of ordinary skill in the art that in some instances some features of the invention will be employed in the absence of a corresponding use of other features. The illustrative examples therefore do not define the metes and bounds of the invention and the legal protection afforded the invention, which function is served by the claims and their equivalents.