Buckles – buttons – clasps – etc. – Bale and package ties – hose clamps – Plastic band
Reexamination Certificate
2001-05-15
2003-03-11
Sakran, Victor (Department: 3677)
Buckles, buttons, clasps, etc.
Bale and package ties, hose clamps
Plastic band
C024S0170AP, C024S03050P
Reexamination Certificate
active
06530126
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of Invention
The present invention relates generally to a low thread force two piece cable tie. More particularly, the invention relates to a locking device for such a cable tie that has an integral protruding tang serving as an anchoring device.
2. Description of Related Art
Plastic cable ties having metal locking device inserts are well known in the art. Examples of such include U.S. Pat. No. 3,457,598 to Mariani and U.S. Pat. No. 5,517,727 to Bernard et al.
Cable ties of this type include a metal locking device partially embedded at an angle within a strap accepting channel of a cable tie head. The metal locking device is situated at an angle that allows insertion of a cable tie strap in an insertion direction, but allows for engagement of the locking device with the strap when it is pulled in a removing direction to prevent removal. The metal locking device of such cable ties is in the form of a cantilevered beam that is fixed at one end and extends into the strap accepting channel at the free end. Operation of such a cable tie will be described with respect to
FIGS. 1-3
, which show operation of a cable tie device according to copending U.S. Patent Application Ser. No. 09/858,049, the subject matter of which is incorporated herein by reference in its entirety.
The cable tie
100
of
FIG. 1
includes a strap
104
(partially shown) integral with a cable tie head
102
. Cable tie head
102
is formed with a locking device receiving cavity
180
and a strap accepting channel
122
having a strap entrance
168
and a strap exit
166
. Strap accepting channel
122
receives the leading end
112
of strap
104
. Locking device receiving cavity
180
receives a preformed metal locking,device
136
, which is formed from a corrosion resistant metal such as stainless steel.
Locking device receiving cavity
180
is provided to allow access to the anchoring region on the end wall for partial embedding of metal locking device
136
in a mounting slot
130
of the cable tie head
102
. Mounting slot
130
may be preformed in an interior surface of cavity
180
or may be partially formed as a result of pressing an end
134
of locking device
136
into the interior surface of cable head
102
. This defines a cantilever beam structure having a fixed end
134
and. a free end
138
that extends into strap accepting cavity
122
. Metal locking device receiving cavity
180
also allows for movement of locking device
136
.
As shown in
FIG. 1
, upon insertion of strap end
112
into the strap accepting channel, the free end of metal locking device
136
freely flexes due to the resiliency of the metal and the angle of the device to provide a low insertion force. Insertion of the cable tie strap continues to occur until strap
104
is sufficiently tight around an object to be constrained, such as an unshown cable bundle. Upon release of the strap, or through application of a withdrawal force on the strap, forces flex free end
138
of metal locking device
136
and cause a sharpened portion of free end
138
to begin to pierce strap
104
as shown in FIG.
2
. When free end
138
sufficiently rests upon the fulcrum point
142
, resistance to further withdrawal is attained up to a determinable tensile strength value, which is dependent on material selection and other variables.
Such a cable tie is sufficient for a single locking application (i.e., a single tightening operation). However, what occasionally happens is that after an initial tightening or attempt to withdraw the cable tie strap
104
, a subsequent tightening or re-threading action may be initiated to further cinch down the cable tie. As the free end
138
of metal locking device
136
has already partially penetrated the surface of strap
104
, it is possible that during these further re-thread attempts to advance the strap in the direction of exit
166
, the free end will not break free from strap
104
. Instead, the locking device
136
will remain partially embedded within the surface of strap
104
. In such cases, if the retention force of the fixed end
134
is less than the withdrawal force necessary to break away free end
138
from strap
104
, it is possible that fixed end
134
will be pulled out of slot
130
. This is undesirable and results in cable tie failure as shown in
FIG. 3
, in which metal locking device
136
is either completely removed or sufficiently withdrawn from slot
130
to adversely affect proper cable tie functioning. In this example, the retention force acting on fixed end
134
to resist removal is the frictional force between fixed end
134
and slot
130
. This retention force may be insufficient and is particularly problematic where the fixed end is oriented substantially parallel to the re-threading force acting on strap
104
toward exit
166
, as in this example.
There is a need for a two-piece cable tie having an improved anchor retention system for a metal locking device.
There also is a need for a method of easily forming a barbed tang on a metal locking device of a cable tie to serve as an anchor.
SUMMARY OF THE INVENTION
It is an object of the invention to provide a two-piece cable tie with a locking device that has improved anchoring force to resist removal during initial and subsequent re-threading.
It also is an object of the invention to provide a method of forming a barbed tang on a metal locking device of a cable tie.
It is further an object of the invention to punch one or more tangs onto a metal locking device so as to form a ramp that is in a direction conducive to installation but provides resistance to attempts to withdraw the device.
The above and other objects are achieved by a cable tie having an anchored metal locking device, comprising: a strap including a first end and a free end; a locking head secured to the first end of the strap, the locking head defining a strap accepting channel in the head having a strap entry end and a strap exit end, the locking head further including a metal locking device receiving cavity adjacent to and open toward the strap exit end of the locking head, the locking head further including a mounting slot having an inner support wall, an outer support wall and a, support slot communicating the mounting slot with the receiving cavity; and a metal locking device mounted through the metal locking device receiving cavity into the support cavity, the metal locking device having a free end positioned within the strap accepting channel and a fixed end having at least one bent tang protruding outwardly from a surface of the metal locking device. The fixed end having the at least one bent tang is insertable through the support slot. Upon such insertion, the inner support surface of the mounting slot resiliently urges at least a protruding edge of the at least one bent tang against the outer support surface to anchor the metal locking device within the mounting slot and resist withdrawal of the metal locking device in a direction towards the exit end of the strap accepting channel.
The invention also provides a method of forming a cable tie having an improved anchoring system comprising the steps of: forming a cable tie having a strap including a first end and a free end and a locking head secured to the first end of the strap, the locking head defining a strap accepting channel in the head having a strap entry end and a strap exit end, the locking head further including a metal locking device receiving cavity adjacent to and open toward the strap exit end of the locking head, the locking head further including a mounting slot having an inner support wall, an outer support wall and a support slot communicating the mounting slot with the receiving cavity; forming a metal locking device with a fixed end having at least one bent tang and a free end; initially mounting the metal locking device through the metal locking device receiving cavity into the mounting slot by inserting the fixed end through the support slot until the fixed end is urged against the inner support wall; and further inserting the metal locking d
Brownlee James A.
Caveney Jack E.
Krisel Robert J.
Leszczewicz Joseph P.
Clancy Christopher S.
McCann Robert A.
Panduit Corp.
Sakran Victor
Saltzman Jay A.
LandOfFree
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