Tools – Wire stripper – Pivoted blade
Reexamination Certificate
1999-11-23
2001-12-04
Smith, James G. (Department: 3723)
Tools
Wire stripper
Pivoted blade
C030S090100
Reexamination Certificate
active
06324945
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to cable preparation tools, specifically to an improved tool and an accompanying method which, when utilized concurrently, prepare fully shielded cables for termination into connecting devices.
Improvements in telecommunications systems have resulted in the ability to transmit voice and/or data signals along transmission lines at increasingly higher frequencies. Several industry standards specify that multiple performance levels of twisted-pair cabling components have been established. The primary references, considered by many to be the international benchmarks for commercially based telecommunications components and installations, are standards ANSI/TIA/EIA-568-A (/568), Commercial Building Telecommunications Cabling Standard, and 150/IEC 11801 (/11801), Generic Cabling for Customer Premises.
Standards /568 and 11801, as well as other existing national and regional standards, specify use of category
3
,
4
and
5
cable and connecting hardware. In these specifications, transmission requirements for Category
3
components are specified up to 16 MHZ. Transmission requirements for Category
4
components are specified up to 20 MHZ. Transmission requirements for Category
5
components are specified up to 100 MHZ.
New standards are being developed continuously and currently it is expected that future standards will require transmission requirements of at least 600 MHZ. To achieve such transmission rates, fully shielded twisted pair cable, as shown generally at
10
in
FIG. 1
, will be necessary. Such cable contains individual insulated wires
16
that are paired with each pair being wrapped in a metallic foil
18
. Then the pairs are wrapped together in another layer of foil or screen
14
, and finally bound within an insulative jacket
12
.
The above referenced transmission requirements also specify limits on near-end crosstalk (NEXT). Telecommunications connectors are organized in sets of pairs, typically made up of a tip and ring connector. As telecommunications connectors are reduced in size, pairs are placed closer to each other creating NEXT between adjacent pairs.
To comply with the NEXT requirements, a variety of techniques are used in the art. U.S. patent application Ser. No. 09/047,046, now U.S. Pat. No. 6,224,423, incorporated herein by reference, describes an enhanced performance telecommunications connector, appearing generally at
20
in
FIG. 2
, which utilizes overlapping shield members to provide enhanced shielding and reduced crosstalk in the mating of fully shielded cable connectors.
FIG. 3
depicts an exemplary process for installing a cable
10
in a connector
20
. The cable is first prepared as shown in
FIG. 4. A
length (shown as A) of the cable jacket
12
is removed. Then, a second length (shown as B) of the metallic foil
18
is removed. As shown in
FIG. 3
, the individual wires
16
are aligned and then inserted into termination caps
22
. The termination caps
22
are then clamped down to terminate wires
16
on insulation displacement contacts in connector
20
.
Traditional methods of preparing fully shielded cable for connector installation require the installer to take measurements by hand, execute multiple stripping actions using several tools, including sharp blades, and arrange wires
16
by hand for insertion into connector. Distances A and B are typically hand measured by the installer. Conventional cable preparation tools, such as that illustrated in
FIG. 5
or that produced by Sargent Tool Company, commercially available as ‘8700 Easy Strip Compress Tool’, can be used to remove cable jacket
12
. Such conventional tools, however, fail to assist the installer in removing foils
18
and aligning inner wires for insertion into connector. A straight blade, such as a knife or scissors, is traditionally used to individually remove metallic foil
18
. Then the installer must visually align wires
16
by hand for insertion into termination caps
22
.
Prior art methods of cable preparation involve several tools, multiple steps and result in considerable installation time. Removal of metallic foil
18
by use of an open blade exposes the installer to safety hazards and threatens the severance of individual insulated wires
16
. Once wires
16
are exposed, the cable must be installed in the connector. Manual arrangement of wires
16
is time consuming and subject to installer error. If the wires are inserted improperly into the connector, the connector will fail to function properly and additional time and resources will be consumed in making the appropriate corrections. Hence, the need has arisen for a invention which allows a fast, simple, and safe method of preparing fully shielded cable for connector termination by use of one, low-cost tool.
SUMMARY OF THE INVENTION
The above-discussed and other drawbacks and deficiencies of the prior art are overcome or alleviated by the cable preparation tool and cable preparation method of the present invention. The cable preparation tool is designed for use with shielded cable including a plurality of pairs of wires, each pair of wires surrounded by a metallic foil. The tool includes first and second tool handles, a blade assembly, and a template assembly provided in one of said first and second tool handles. A method of preparing the shielded cable includes inserting the cable in a cutting portion of the tool and cutting the cable jacket using the tool. The outer cable jacket is removed and the pairs of wires are placed in the cutting portion of the tool. Each of the foils is cut in one step using the tool.
REFERENCES:
patent: Re. 30342 (1980-07-01), Perrino
patent: 3872746 (1975-03-01), Wittes et al.
patent: 4188702 (1980-02-01), Herbert
patent: 4480374 (1984-11-01), Meyer
patent: 4485696 (1984-12-01), Bieganski
patent: 4677702 (1987-07-01), Cairns
patent: 5009006 (1991-04-01), Sawyer et al.
patent: 5150522 (1992-09-01), Gwo-Jiang
patent: 5265339 (1993-11-01), Nilsson
patent: 5351333 (1994-09-01), Chambers
patent: 5402561 (1995-04-01), Cerquone et al.
patent: 5435029 (1995-07-01), Carlson, Jr. et al.
patent: 5713132 (1998-02-01), Tarpill
patent: 6058606 (2000-05-01), Hepworth
patent: 6224423 (2001-05-01), Yip et al.
patent: 0 376 505 A1 (1990-04-01), None
patent: 0 793 307 A2 (1997-09-01), None
patent: 0 871 270 A2 (1998-10-01), None
Lo Denny
Valentukonis David
Cantor & Colburn LLP
Shakeri Hadi
Smith James G.
The Siemon Company
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