Patent Application
20090235531
1. Field of the Invention
The present invention relates generally to apparatus for cutting the outer tube of steel conduit cables, and, more particularly, for cutting the outer tube of such conduit cables that contain electrical or optical cables.
2. Description of the Prior Art
The installation of electrical steel conduit cables on-site requires that the outer tube be cut to the required length for termination and pressure sealing. Such a tube has a relatively thin wall and cutting the tube requires a great deal of skill not to damage the electrical insulation inside the tubing. While a triangular file is often used for such cutting, the site conditions can prevent the technician gaining access to both view and perform the required 360° cut with a suitable filing action. If two cables exist in a side by side relationship, this task is doubly more difficult.
Conventional tube cutters require a lot of space and the cutting device often uses a hardened steel blade which rotates around the tube, cutting into the material by cold working and deformation of the tube wall material. This type of cutter causes a flow of material into the inside bore and can damage the cable insulation as a result of this “necking” and the sharp edge that then results when the cable is broken.
A tool would therefore be advantageous that performs a cutting action that notches the tubing without deformation to the tube bore and that it is able to be operated between at least two exiting cables in close proximity to one another. It would also be advantageous if the tool could produce a chamfer at the same time to allow seals to be fitted over the tubing without damaging the seals when fitted.
In accordance with the present invention, tube cutter apparatus is provided comprising a body which is generally cylindrical in shape and which has a bore through the body. The tube cutter apparatus further comprises a device to prevent lateral movement of the tube to be cut during a cutting operation, and a revolving unit containing a tool for cutting the tube.
In one embodiment, tube apparatus according to the present invention includes a bearing tube which defines a portion of the bore and through which the tube that is to be cut is inserted. A coupling radially surrounds a portion of the bearing tube and is in contact with the bearing tube. The coupling comprises at least one device to secure the tube to be cut in place when the tube is inserted in the bore and thereby prevent lateral movement of the tube during the cutting operation.
In one embodiment, the revolving unit of tube cutter apparatus in accordance with the present invention comprises a retaining flange proximate the coupling wherein the retaining flange also engages a portion of the load bearing tube. In this embodiment, the revolving unit also includes a rotary tool holder which is proximate the retaining flange and which is also in contact with a portion of the bearing tube, and the rotary tool holder includes a cutting tool for cutting the tube. The revolving unit of this embodiment additionally comprises an end flange proximate the rotary tool holder, and the end flange the retaining flange and the rotary tool holder are coupled together so that they may revolve as a unit.
Tube cutter apparatus in accordance with the present invention further comprises apparatus for setting the depth of cut of the cutting tool and for setting the point at which the cutting operation stops. In one embodiment, this apparatus includes a grub screw to set the depth of cut of the cutting tool and a second grub screw to set the stop point for the cutting tool.
A tube cutter according to the present invention produces a chamfered cut on the tube. This chambered end facilitates the attachment of seals to the end of the tube that has been cut.
In one embodiment, the securing device in the coupling comprises at least one socket cap screw.
In the accompanying drawings:
It will be appreciated that the present invention may take many forms and embodiments. In the following description, some embodiments of the invention are described and numerous details are set forth to provide an understanding of the present invention. Those skilled in the art will appreciate, however, that the present invention may be practiced without those details and that numerous variations and modifications from the described embodiments may be possible. The following description is thus intended to illustrate and not to limit the present invention.
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The revolving unit of tube cutter apparatus 10 in accordance with the present invention further includes an end flange 18 which is proximate to the rotary tool holder 14. The combination of end flange 18, rotary tool holder 14 and retaining flange 12 may be coupled together by using screws 19, and screws 24 may be utilized to further couple retaining flange 12 and rotary tool unit 14 together.
The revolving unit of tube cutter apparatus 10 further comprises devices for setting the depth of cut of the cutting tool and for setting the point at which the cutting tool will stop cutting the tube. In the embodiment illustrated in
By utilizing tube cutter apparatus 10 in accordance with the present invention, the cutting of two tubes which are in proximity to one another is facilitated. In addition, the cutting tool 16 produces a chamfered cut 30a on tube 30 as illustrated in
While the present invention has been described with respect to a limited number of embodiments, those skilled in the art, having the benefit of this disclosure, will appreciate numerous modifications and variations therefrom. It is intended that the appended claims cover all such modifications and variations as fall within the true spirit and scope of this present invention.
