Optical Fiber Access Tool

Stripping tools used for stripping tubes holding copper communications media have been known for many years. More recently, tube slitters have been developed for optical fiber cables. For instance, Genovese, et al, U.S. Pat. No. 4,947,549, disclose such a tool having blades mounted on opposing sides of a passage.

It has been observed in the cabling of optical fibers that when loosely tubed light waveguides proceed around a sheave, light waveguides tend to migrate towards the inside of the curve. This observation has led to various methods for obtaining excess fiber length. The present invention incorporates this feature in a novel manner into the tube slitting tool art. Therefore, the tube slitting tool according to the invention provides at least two elongated members having grooves therein and forming, when the elongated members are closed, a bore having a longitudinal axis for confining a tube therein. This bore is partly delimited by a first groove, the first groove in a plane containing the longitudinal axis of the bore; the first groove has an apex within the bore and the distance of the first groove from the longitudinal axis steadily increases proceeding away from the first groove apex in either direction in the bore along the longitudinal axis. A first blade, and optionally, a second blade mounted parallel to the first blade on an elongated member extends radially into the bore confronting the first groove apex when the elongated members are closed. By this construction, the tube slitting tool may be drawn along a tube for mid span access of a loose tube optical waveguide cable with the tube following the first groove in the bore. Since the optical waveguides within the tube will tend towards the first groove, the waveguides will tend to migrate away from the blade or blades.

In order to ease use of the tool and reduce friction as much as possible, the first or the first and second blades may be mounted extending from a second groove in an elongated member groove whose apex confronts the first groove apex and the second groove distance from the longitudinal axis steadily increases proceeding away from the second groove apex in either direction along the longitudinal axis. Thus, the entire bore flares outwardly from the position of the blade or blades.

The description of the preferred embodiment will be set out with reference to the drawing figures described below.

FIG. 1 is a perspective view of the tool in an opened position, with components separated slightly for clarity;

FIG. 2 is a perspective view of the tube in its closed position;

FIG. 3 is a side elevation view of the tool in its closed position; and,

FIG. 4 is a sectional view along lines 4-4 of FIG. 2.

The tool first elongated member (base) 8 is hinged and mounted to second elongated member 15 by dowel pins 10. Second elongated member 15 includes blade holder member 14 having slots 18 therein. Blades 13 are seated in blade slots 18 by the use of blade dowel pins 21. For machine production, it is preferable to seat blade dowel pins 21 in elongated member 17 so that a thicker metal is available for this purpose. Screws 6, 12 hold the components of second elongated member 15 together during use. First elongated member 8 and second elongated member 15 may then be closed, forming bore 19. Wing fastener 7, having washer 9, may be inserted through latch 16 to hold the tool closed during use. When the tool is closed, bore 19 is partially delimited by first groove 11 and second groove 17. When the tool is closed, blades 13 extend from second groove 17, blades 13 being parallel to each other and confronting the apex of first groove 11. Viewing the longitudinal section in FIG. 4, it is seen that blades 13 extend from the apex of second groove 17 to face the apex of first groove 11. All tool components should be formed from a rigid, durable metal.

Since the tool according to the invention is contemplated for use as a mid-span access tool, the arrows in FIGS. 2, 4 indicate the motion of the tool as it is pulled along buffer tube 48. The outer jacket and strength members of a cable should be removed over a length of buffer tube which is to be slit. As the tool is moved in the direction of said arrows, light waveguides 20 tend to approach the tube wall adjacent to first groove 11. This tendency is an important factor in keeping light waveguides 20 away from blades 13 as blades 13 slit the outer jacket of tube 48.

After the tube is slit, a ring (transverse) cut may be made in the tube in order to remove the slit section of tube.