Buckles – buttons – clasps – etc. – Bale and package ties – hose clamps – Plastic band
Reexamination Certificate
1998-11-20
2001-02-13
Sakran, Victor N. (Department: 3626)
Buckles, buttons, clasps, etc.
Bale and package ties, hose clamps
Plastic band
C024S0170AP, C024S03050P
Reexamination Certificate
active
06185792
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates generally to a self-locking cable tie for securing a plurality of wires or similar articles. More particularly, the present invention relates to a bi-directional cable tie which allows strap insertion though the head in either direction.
BACKGROUND OF THE INVENTION
The use of cable ties to bundle a plurality of wires or similar articles has long been known. Basic cable tie construction includes an elongate cable tie strap having a tail at one end and a head at the other end. The head includes a central passage or aperture therethrough for accommodating a tail in an insertable fashion. The head supports a locking device adjacent the head aperture to securely lock the cable tie body within the aperture of the head to provide securement of the cable tie about the bundle of wires. In one type of cable tie construction, the locking device is a flexibly supported integrally formed pawl having plastic teeth which engage corresponding teeth on a cable tie body to provide locking engagement therebetween. As is typical of most cable ties, the tail of the cable tie is inserted into the head aperture uniquely in one direction. However, the art has also seen the use of bi-directional, or symmetrically-formed, cable ties which permit the cable tie tail to be inserted through the aperture in the head in either direction.
One such bi-directional cable tie is shown and described in co-pending commonly assigned U.S. application Ser. No. 08/689,466, filed Aug. 9, 1996, entitled “A Self-Locking Cable Tie Strap With Symmetrical Structure”, issued on Mar. 23,1999, as U.S. Pat. No. 5,884,367 which is herein incorporated by reference for all purposes. The cable tie of such construction may be particularly used with an automatic cable tie installing device where a plurality of cable ties held together in a reel. A cable tie from the reel may be fed from a dispenser to a cable tie installing gun for installation about a plurality of wires. The symmetrical construction of the cable tie permits the cable tie to be easily dispensed and aligned within the installation gun. As may be appreciated, in order to accommodate insertion of the cable tie tail from either direction, the pawl or locking device of the symmetrical cable tie must be sufficiently flexible to permit deflection in either direction. Such flexibility assures that the cable tie tail may be easily inserted through the aperture in the head in either direction.
While such flexible construction permits easy insertion, it has been found that in certain circumstances such cable ties may not exhibit sufficiently high resistance to withdrawal forces as may be required in certain applications. Additionally, the art has uniformly provided bi-directional cable ties having symmetrical withdrawal-resistance characteristics while ignoring circumstances where it may be desirable to provide a bi-directional cable tie exhibiting discretely selectable, or non-symmetrical, withdrawal-resistance characteristics depending upon which direction the cable tie strap is inserted through the head.
Accordingly, it is desirable to provide a cable tie having a self-locking feature in a symmetrical structure which exhibits ease of insertion of the cable tie strap into the aperture in either direction and yet provides suitably high resistance to withdrawal forces in order to maintain a self-locking configuration. Additionally, it is desirable to provide a self-locking feature in an asymmetrical structure which offers discretely-selectable resistance to withdrawal forces according to the direction of strap insertion.
SUMMARY OF THE INVENTION
It is an object of the invention to provide a bi-directional cable tie for bundling one or more articles.
It is another object of the invention to provide a bi-directional cable tie having improved performance characteristics.
It is still another object of the invention to provide a bi-directional cable tie having a fixed locking teeth capable of engaging the teeth on the other side of the strap body as those engaging the locking pawl.
It is yet another object of the present invention to provide a bi-directional cable tie providing asymmetric performance characteristics in that the hoop strength depends on the direction through which the strap body is inserted into the passageway.
It is even yet another object of the present invention to provide a bi-directional cable tie with the locking teeth of the locking pawl include an undercut strap engaging surface so as to increase the range of pawl deflection providing locking engagement between the pawl and the strap body.
In the efficient attainment of these and still other objects, the present invention provides a bi-directional cable tie for bundling one or more articles having a locking head at one end, a tail at the other end and an elongate strap body therebetween. The strap body includes opposing first and second major surfaces having a plurality of locking teeth formed on each major surface. The locking head includes a first opening, a second opening, and an elongate strap passageway extending therebetween in a direction substantially perpendicular to the strap body. The head also provides opposed shoulder and block surfaces extending along the passageway. The shoulder surface provides a first rotation stop surface adjacent the first opening and a second rotation stop surface adjacent the second opening. A deflectable locking pawl extends from the shoulder surface into the passageway across from the block surface. The locking pawl is substantially aligned with the strap body and is deflectable by the strap body upon insertion of the strap body in either direction through the passageway. The locking pawl also provides locking engagement with the strap body upon attempted withdrawal of the strap body in a direction opposite to the insertion direction. The locking pawl includes a locking portion having a first locking tooth facing both the first opening and the passageway and a second locking tooth facing both the second opening and the passageway, and an elongate pawl base including a first cantilever arm having a first free end extending towards the first opening and a second cantilever arm having a second free end extending towards the second opening. The pawl base is connected to the shoulder by a flexible hinge which defines the closed end of both a first notch bounded by the first cantilever arm and the first stop surface and opening towards the first opening of the head, and a second notch bounded by the second cantilever arm and the second stop surface and opening towards the second opening of the head. When the strap body is inserted through one end of the passageway it contacts the near locking tooth of the locking pawl and causes the locking pawl to translate and rotate about the flexible hinge towards the opposite end of the passageway so that the free end of the oppositely-extending cantilever arm engages its opposing rotation stop so as to close the notch opening towards the exit end of the passageway. Attempted withdrawal of the strap body back through the passageway causes the contacted locking tooth of the pawl to engage a locking tooth of the strap body and counter-rotate the locking pawl about the hinge to thereby force the strap body against the block surface of the head; and
The present invention also contemplates increasing the hoop strength of the cable tie of the present invention by providing one or more fixed locking teeth on the block surface of the cable tie head for engaging the locking teeth on the opposite surface of the strap as those engaging the deflectable pawl. In one embodiment of the present invention a fixed locking tooth is provided adjacent each opening so as to engage the strap upon withdrawal back through the adjacent opening. The fixed locking teeth are symmetrically provided so as to offer substantially the same performance characteristic regardless of the insertion direction of the strap body through the passageway in the head.
In another embodiment of the present invention a fixed locking
Nelson Andrew
Wells, Jr. Peter M.
Hoffmann & Baron , LLP
Sakran Victor N.
Thomas & Betts International Inc.
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